Note: Descriptions are shown in the official language in which they were submitted.
972S
The present invention relates to high frequency excited
electrodeless discharge lamps, and more particularly to improve-
ments in the composition of the fill materials thereof which/
when excited, emit light that is particularly rich in the near
ultraviolet light range.
This application is a divisional application of copend-
ing application No. 400168 filed March 31, 1982.
Near ultraviolet light sources which are often used for
processes involving photochemical reactions, such as photoengrav-
0 ing, have co~only comprised high pressure metal vapour electricdischarge lamps which have a pair of discharge electrodes disposed
within the envelope thereof. Such electric discharge lamps have
generally comprised fill materials including halides of gallium,
etc., and thus have been called metal halide lamps. This type
of conventional metal halide lamps is disadvantageous, however,
in that the stabilization time, i.e., the length of time that the
lamp requires to attain the stable state of light emission after
it is turned on, is relatively long, i.e., as long as about three
minutes. Thus, when this type of conventional metal halide lamps
is used in the photoengraving process in which exposure and pre-
paration steps follow one after another at short intervals of one
minute, the lamps cannot be turned off during the preparation
steps between the exposure steps.
~17~72S
It has thus been necessary to keep the lamp continuously
turned on behind a shutter during all of the operations of
the photoengraving process, opening the shutter during the
exposure steps in which the light is required. This causes
much loss of electric power. Thus, the so-called instant
,
stabilization type ultraviolet light sources have been much
needed. Further, conventional metal halide lamps constitute
high electrical loads and the life thereof has been limited
to about a thousand hours. This relatively short life is
due, for example, to the stains originating from the
electrodes which accumulate on the inner surface of the
envelope of the lamp.
Thus, light sources have already been proposed in
which electrodeless lamps are exciting by high frequency
waves, especiall~ microwaves. These elecirodeless discharge
lamps enjoy longer life than the conventional lamps with
discharge electrodes, because a main factor limiting the
life of the conventional lamps has been the comsumption of
the electrodes and the stains resulting therefrom. A further
advantage of the electrodeless lamp is that there is no
thermal loss at the discharge electrodes, and that it is
easier to apply greater electric power to the lamp from the
time of turn-on, because the irnpedance of the discharge in
the electrodeless lamps vaires little from the time it is
turned on till it attains the stable sta~e. Also, the
stabilization time of -the electrodeless lamps is shorter
because the electric discharge thereof concentrates near the
inner surface of the envelope of the lamp.
li7972~i
Although the electrodeless discharge lamps have
_ _
many advantages as above described, they have not been
satisfactory as near ultraviolet light sources. That is,
the conventional fill materials thereof did not give enough
light output in the near ultraviolet range, especially in
. ~
the range of 350 to 450 nm length. Such conventional fill
materials are disclosed, for example, in U.S. patent 4,001,632
issued to Haugs~aa et al. on Jan. 4, 1977 as examples I
through III in column 5 thereof.
The mechanism of light emission, however, is
substantially the same in the electrodeless discharge lamps
as in the conventional discharge lamps having discharge
electrodes. Namely, the light emitting metal contained in
the fill material sealed in the envelope of the lamp is
vapourized and excited by the high frequency waves to emit
light. Thus, when higher light emission is required in a
particular wave length range, fill materials comprising
substantially the same kind of light emitting metals must be
sealed in the envelope in the electrodeless lamps as in the
conventional lamps having discharge electrodes. The light
emission in the case of the conventional metal halide lamps
having discharge electrodes, however, concentrates near the
axis between the discharge electrodes, which are situated at
the two end portions of the envelope, in contrast to the
case of the electrodeless discharge lamps in which the light
emission extends to the meighbourhood of the inner surface
of the envelope even when the vapour pressure within the
envelope of the lamp is high.
-- 3
:1~79~ZS
Thus, the amounts of fill materials which are suitable
for the conventional metal halide lamps and which are suitable
for the electrodeless lamps are different even when fill materials
including the same kind of metals are used.
Thus, the present invention provides an improved high
frequency excited electrodeless lamp which emits light that is
particularly rich in the near untraviolet range, especially in
the range of 350 to 450 nm wavelength. More particularly, the
present invention provides fill materials for the high frequency
excited electrodeless discharge lamps which give sufficient light
emission in the near ultraviolet range, especially in the 350 to
450 nm wavelength range.
In copending application No. 400168 the fill material
sealed within the light transmitting envelope of the electrode-
less lamp comprises a rare gas, mercury, a halogen, and a metal
selected from the group consisting of iron, nickel, cobalt,
palladium, and the mixtures thereof. The fill material comprises,
per one cubic centimeter of the volumetric content of the envelope
of the lamp, mercury in an amount from 7 to 55 preferably from
17.6 to 41.3 and more preferably around 25, micromoles, the metal
selected from the group in the total amount from 0.1 to 2.3, pre-
ferably from 0.38 to 1.91 and more preferably from 0.5 to 1, micro-
moles, and the halogen in a total amount ranging from 0.2 to 6.2
micromoles in terms of atoms or
-- 4 --
11797~5
irons thereof. Preferabl~, the amount of halogen atoms
measured in terms of micromoles per one cubic centimeter of
the content of the envelope exceeds twice the amount of the
metal selected from the group measured in the same terms,
by an amount ranging from 0.02 to 2.0 micromoles. That is,
it is preferable that there is enough h~logen for changing
all the metal selected from the group into the halide thereof.
It is further preferred that the raregas is present in the
envelope at a pressure ranging from lO to 200, preferably
from 20 to 150 and more preferably from 30 to 130, torr.
The micromole unit used in the above measurements
is equal to lO 6 moles. The mole unit is the SI unit which is
equivalent to the former corresponding units such as gram-atom
or gram-molecule.
According to the present invention,
the fill material sealed within the envelope of the lamp
comprises a rare gas, mercury, a halogen, and a rare earth
metal selected from the group consisting of dysprosium,
holmium, thulium, scandium, and the mixtures thereof. It is
preferred that the fill material comprise, for each one cubic
centimeter of the content of the envelope, mercury in an
amount ranging from 5 to 55 preferably from 17.6 to 53,
micromoles, a rare earth metal in a total arnount ranging
from 0.05 to 0.6 preferably from 0.13 to 0.39 ar~d more
preferably around 0.25, micromoles, and halogen in a total
amount ranging from 0.15 to 0.62 micrornoles in terms of atoms
thereof. It is preferred that the amount of halogen atoms
atoms measured in terms of micromoles per one cubic centimeter
of the volumetric content of the envelope exceed three times
1 ~ 79 ~ ~
the amount of rare earth metal measured in the same terms.
That is, it is pre~erred that there be enough halogen to
combine with all the rare earth metal present in the envelope
to form the halide thereof.
n the invention, the halogen may
~e iodine, bromine, or a mixture thereof, and the rare gas
may be argon.
Further details of the present invention will
become more apparent from the following detailed description
of the preferred embodiments, taken in conjunction with the
accompanying drawings, in which:
Fig. 1 is a schematic cross-sectional view of the
microwave generating device in which the electrodeless
aischarge lamp according to the present invention may be
disposed;
Fig. 2 is a cross-sectional view of an electrodeless
lamp accoring to the present invention;
Fig. 3 shows the curve representing the relationship
between the near ultraviolet output of an electrodeless lamp
and the iron iodide content sealed in the envelope thereof,
wherein the fill material sealed in the envelope of the lamp
comprises the elements iron, iodine, mercury, and aryon, and
wherein the mercury and argon contents are fi~ed;
Fig. 4 shows the curve representing the relationship
between the near ultraviolet output of an electrodelsss lamp
and the mercury content sealed in the envelope thereof,
wherein the fill material sealed in the envelope comprises
1:179725
the elements iron, iodine, mercury, and argon, and wherein
the iron, iodine, and argon contents are fixed;
Fig. 5 shows the curve representing the relationship
between the near ultraviolet output of an electrodeless lamp
and the dysprosium iodide content sealed in the envelope
thereof, wherein the fill material sealed in the envelope
comprises the elements dysprosium, iodine, mercury, and
argon, and wherein the mercury and argon contents are
substantially fixed;
Fig. 6 shows the curve representing the relationship
between the near ultraviolet light output of an electrodeless
lamp and the mercury content sealed in the envelope thereof,
wherein the fill material thereof comprises the elements
dysprosium, iodine, mercury, and argon, and the dysprosium,
iodine, and argon contents are fixed.
- -- Fig. 7 shows the curves representing the variations
of the near ultraviolet light output and the starting time
against the mole fraction of bromine with respect to the
total molar content of bromine and iodine included in the
fill material of an electrodeless lamp.
In the drawings like reference numerals represent
like components.
Referring now to Fig. 1 and 2 of the drawings, a
construction of an electrodeless discharge lamp according to
the present invention is described, together with that of a
microwave generating device in which the lamp according to
the present invention may be disposed.
~797~S
The microwave gener~ting devlce of Fig. 1 comprises a
magnetron 1 generating a microwave of 2450 MHz and having an
output power of 700 W. The magnetron 1 is disposed at an end
portion of a wave guide 3, and has a magnetron antenna 2 from
which the microwave is radiated into the wave guide 3. The wave
guide 3 opens into a cavity 4 enclosed by cavity wall 5 and a
metallic mesh plate 11 at a microwave feeder opening 6. The
cavity wall 5 is formed of a substantially semispherical aluminum
plate and the inner surface thereof forms a light reflecting
surface. The metallic mesh plate 11 is a stainless steel rnesh
plate manufactured by the etching method, and transmits about 85
percent of light therethrough but not the microwave generated
by the magnetron 11. The electrodeless lamp 7 comprises a
spherical envelope 7a formed of light transmitting quartz and a
pair of rod-shaped projections 7b and 7c formed of the same
material and integral therewith. The spherical envelope 7a has
a thickness of 0.5 mm and an inner diameter of 30 mm, thus en-
closing a spherical space of about 14.1 cm , in which an inert
gas, metals, etc., are sealed in a certain composition according
to the present invention, as will be described in detail herein-
after. The projections 7b and 7c have d length of 10 mm and a
diameter of 3 mm, and the electrodeless lamp 7 is supported at
these projections 7b and 7c by supporting members (not shown)
formed on the cavity wall 5. A ventilator fan 8 disposed at an
end of a ventilating duct 9 introduces cooling air into the duct
9 from outside the housing 12 which accommodates .he magnetron 1,
the wave guide 3, etc., and thus cools the magnetron 1 and the
electrodeless lamp 7.
1179725
The operation of the microwave generating device
of Fig. 1 will be described, together with that of an ~
electrodeless lamp according to the present invention. The
microwave generated by the magnetron 1 is radiated into the
wave guide 3 from the magnetron antenna 2, and then is
propagated through the wave guide 3 and radiatéd into the
cavity 4 from the feeder opening 6, thereby forming a microwave
electromagnetic field in the cavity 4. Thus, the electrodeless
lamp 7 is placed in the microwave electromagnetic field
established in the cabity 4, and the inert gas, which is
sealed in the lamp 7, for starting the electric discharge
within the lamp 7, begins to discharge, thereby beating the
inner surface of the envelope 7a of the electrodeless lamp
7. Thus, the metals aeposited on the inner surface of the
envelope 7a of the lamp 7 begin to evaporate, filling the
space within the envelope 7a with metal vapor. Thus, the
electric discharge within the envelope 7a is now carried out,
for the main part thereof, by the metal vapor, and is stabilized
when the metal vapor discharge takes place, the metal vapor emits
light having the emission spectra characteristic of the metals.
This light emitted from the metal vapors is utilized as a
light source. Further, in order to effectively utilize the
light emitted from the electrodeless lamp 7, the inner surface
of the cavity wall 5 is made light reflecting, and the front
of the cavity 4 is covered by the metallic mesh plate 11 which
transmits light but not microwaves. Thus substantially
all the light emitted from the electrodes lamp 7 is radiated
_ g _ .
1~7972S
forward through the mesh plate 11. Further, as it is '
necessary to remove heat generated in the~magnetron 1 and
the lamp 7, the ventilating fan 8 takes in the outside air,
which then blows through the duct 9, the opening 10, the
wave guide 3, the feeder opening 6, and the cavity 7, and is
exhausted from the cavity 7 through the mesh plate 11. `
We have conducted a series of experiments to
determine the optimum composition of the fill material of
an electrodeless discharge lamp which can be used as near an
ultraviolet light source. In all the experiments described
hereinbelow, the electrodeless discharge lamp 7 of Fig. 2
having the physical construction and dimensions described
hereinabove was used and placed in the microwave generating
device of Fig. 1. Thus, the volumetric content of the
envelope 7a is 14.1 cubic centimeters, and it should be
understood that when the amounts of substances-contained in
the fill material of the lamp 7 are expressed in terms of
micromoles per cubic centimeter, the actual molar amounts of
the substances contained in the fill material are obtained
by multiplying the values expressed in terms of micromoles
per cubic centimeter by the factor of 14.1 cubic centimeters.
Further, it should be obvious that when electrodeless
discharge lamps having a larger or smaller volumetric content
are used, the actual amounts of the substances of the fill
material should be increased or decreased in proportion to
the volumetric content of the envelope. The physical
construction and the dimensions of the electrodeless lamp 7
of Fig. 2 were described hereinabove only for exemplary
- 10 -
~.J 79725
purposes, and the scope of the invention is not limited to
.
the particular form or dimensions of--the lamps-of-Fig. 2. -:-
In all the experiments described hereinbelow,
except for the last one of Fig. 7, the light outpu~ of the
lamp 7 in the near ultraviolet range of 355 to 425 nm has
._.
been measured on an arbitary scale, in which the electrodeless
discharge lamp formerly developed in our laboratory and
including gallium as the light emitting metal scored a value
65.
Referring now to Figs. 3 and 4 of the drawings,
the first series of experiments in which the fill material
o~ $he lamp 7 comprising the elements iron, iodine, mercury,
an~ argon, is described.
Fig. 3 shows the dependence of the light output on
the iron iodide content of the fill material. Namely, fixed
amounts of argon and mercury, i.e., argon at pressure of 100
torr as the starter rare gas and mercury in an amount of 120
mg (or 42 micromoles per cubic centimeter of the content of
the envelope 7a) as the buffer gas were sealed in the envelope
7a of the lamp 7. Further, a variable amount of iron iodide
(FeI2) was sealed in and the dependance of the light output
of the lamp 7 on the amount of iron iodide was measured.
Thus, the fill material used in this experiment comprised
fixed amounts of the elements mercury and argon, and variable
amounts of the elements iron and iodine. The amount of
iodine in terms of moles was two times that of iron. The
elements iron and iodine could of course be sealed in the
form of metallic iron and mercury iodide (HgI2), keeping the
~17~72S
ratio of the amount of these elements in terms of moles at
1:2. - - -- -
- As shown in Flg. 3, the light output in the near
ultraviolet range increases rapidly at first with increase
in the amount of iron iodide sealed in the envelope 7a, and
reacXes a maximum when the amount of iron iodide is between
0.5 and 1.0 micromoles per cubic centimeter. An amount of ~~~~
iron iodide between 0.1 and 2.3 micromoles per cubic
centimeter is practically feasible. When the amount of iron
io~ide sealed in the envelope 7a is less than O.1 micromoles,
it is difficult to seal in the precise predetermined amount
of iron iodide due to measurement errors and fluctuations in
t~e parameters in the manufacture of the lamp, and thus the
near ultraviolet light outputs of the product lamps vary
considerably from each other. Further when the amount of
~ron iodide sealed in the envelope 7a exceeds 2.3 micromoles
per cubic centimeter, the discharge within the envelope 7a
becomes unstable and fluctuates, presenting a striped pattern
therein.
Fig. 4 shows the dependance of the near ultraviolet
light output of the electrodeless lamp 7 upon the mercury
content of the fill material thereof. The argon gas was
sealed at fixed pressure of 100 torr as the starter gas, and
iron in the fixed amount of 0.63 micromoles per cubic
centimeter was sealed in the envelope 7a as the light emitting
metal, together with mercury iodide in the fixed arnount of
0.62 micromoles per cubic centimeter. The amounts of these
substances were fixed at these values while the amount of
- 12 -
1:1'797ZS
- .
.
mercury sealed in the envelope was changed and the depenaance
, . . . . ....................... . .............. _--
of the light output of the lamp 7 on the amount of mercury
was measured. Thus, in this experiment of Fig. 4, the fill
material comprised the elements iron and iodine in the fixed
amounts of 0.63 and 1.24 micromoles per cubic centimeter,
., - ,- . - . ~
respectivély, and also a fixed amount of argon at a pressure
of 100 torr in the envelope 7a.
As shown in Fig. 4, the light output of the lamp 7
increases at first rapidly with an increase in the amount of
mercury sealed in the envelope 7a, and reaches a maximum
when the amount of mercury is at about 25 micromoles per
cubic centimeter. The light output decreases gradually when
the amount of mercury is increased beyond about this value.
The amount of mercury in the range of from 7 to 55 micromoles
is practically feasible. The reason is that when ~he amount
of mercury is less than 7 micromoles per cubic centimeter,
the light output is not sufficient, and, on the other hand,
when it exceeds 55 micromoles per cubic centimeter, the
light emission in the envelope 7a presents a striped pattern
and becomes unstable with fluctuation.
Further experiments were conducted changing the
pressure of argon gas in the envelope 7a of the lamp 7, the
fill materials of which comprised the same elements as in
the case of the experiments of Figs. 3 and ~. Namely, iron
in the fixed amount of 0.63 micromoles per cubic centimeter
and mercury iodide in the fixed amount oE 0.62 micrornoles
per cubic centimeter were sealed in the envelope 7a, and the
pressure of argon gas in the envelope 7a was changed from 1,
through 5, 10, 40, 100, and 200, to 300 torr.
- 13 -
~17g~25
When the pressure of argon gas is at 1 torr, the
., , ._.
discharge within the envelope extinguished before it reached
the stable state, and when the pressure of argon gas is at
300 torr, the lamp 7 did not start light emission. Thus, it
was found preferable to limit the pressure of argon in the
envelope 7a within the range of ~rom 10 to 200 torr. As the
result of further experiments~ it was found that a more
preferalbe range of the pressure of argon in the envelope 7a
in the case where the fill material comprises iron, iodine,
mercury and argon is between 20 and 150 torr, and a still
more preferable range thereof is between 30 and 130 torr.
~ With regard to the iodine content in the fill
material, an amount thereof necessary to form the sufficient
amount of iron iodide should be sealed in the envelope 7a.
When the iodine is sealed in the envelope 7a in the form of
mercury iodide, the maximum amount of i-odine which can be
sealed in is 1.25 mg, or 6.2 micromoles per cubic centimeter.
The reason of this is that when the amount of iodine in the
fill material exceeds this maximum of 6.2 micromoles per
cubic centimeter the light emission in the envelope 7a
becomes uneven, and the discharge within the envelope 7a
unstable with fluctuations. Thus, the amount of iodine in
the fill material should not be less than 0.2 micromoles per
cubic centimeter, which is necessary to form the minimum
permissible amount of iron iodide of 0.1 micromoles per
cubic centimeter, and not more than 6.2 micromoles per cubic
centimeter. Further, it is preferred that the amount of
iodine measured in terms of micromoles per cubic centimeter
- 14 -
1i7.~7Z~
.. . . . .
exceeds 2 times the a unt of iron measured in the same
terms. Namely, it is preferable that the amount of iodine
exceeds the amount thereof which is necessary to combine
with all the iron present in the fill material. The preferable
excess amount of iodine is from 0.02 to 0.2 micromoles per
cubic centimeter.
Thus, in view of the experiments described above
and also in view of further experiments, we conclude as
follows with regard to the fill materials of an electrodeless
discharge lamp which comprises a rare gas, mercury, a halogen,
and a metal selected from the group consisting of iron,
nickel, cobalt, palladium, and the mixture thereof.
The fill material should comprise, per one cubic
centimeter of the content of the envelope of the lamp mercury
in an amount from 7 to 55 preferably from 17.6 to 41.3 and
more preferably around 2S, micromoles, the metal selected
from the group in overall amount from 0.1 to 2.3, preferably
from 0.38 to 1.91 and more preferably from 0.5 to 1, micromoles,
and the halogen in an overall amount ranging from 0.2 to 6.2
micromoles. Preferably, the amount of halogen measured in
terms of micromoles per one cubic centimeter of the content
of the envelope exceeds twice the amount of the metal selected
from the group measured in the same term by an amount ranging
from 0.02 to 2.0 micromoles. That is, it is preferable that
there is enough halogen for changing all the metal selected
from the group into the halide thereof. It is further
preferred that the rare gas is present in the envelope at a
pressure ranging from 10 to 200 preferably from 20 to 150
and more preferably from 30 to 130, torr.
11'~97ZS
The micromole unit used in the above measurements --~
of the substances involved is equal to 10 6 moles. The mole -;
unit is the SI unit which is equivalent to the former
corresponding units such as gram-atom or gram-molecule
units.
~ ~ Referring now to Figs. 5 and 6 of the~drawings,
the second series of experiments in which the fill material
of the lamp 7 comprised the elements dysprosium, iodine,
mercury, and argon, is described.
Fig. 5 shows the dependence of the light output on
the dysprosium iodide content of the fill material. Namely,
fixed amounts of argon and mercury, i.e., argon at a pressure
of 100 torr as the starter rare gas and mercury in the
amount of 100 mg as the buffer gas were sealed in the envelope
7a of the lamp 7. Further, variable amounts of dysprosium
and mercury iodide were sealed in and the dependence of the
light output of the lamp 7 on the amount of dysprosium
iodide (DyI3) was measured. Namely, variable amounts of
dysprosium and mercury iodide were sealed in the envelope
7a, while keeping the ratio thereof in terms of moles at
1:1.5~ Thusr the ratio of the amounts of dysprosium and
iodine in terms of moles was kept at 1:3, i.e~, there was
just enough iodine to conbine with all the dysprosium to
form dysprosium iodide~ Thus, the fill material used in
this experiment comprised substantially fixed amounts of the
elements mercury and argon, and variable amounts of the
elements iron and iodine.
11~9725
As shown in Fig. 5, the light output in the near
ultraviolet range increases rapidly at first with an increase
in the amount of dysprosium iodide sealed in the envelope
7a, and reaches a maximum when the amoun~ of dysprosium
ioaide is about 0.25 micromoles per cubic centimeter. An
,, ,, , , ,, ,, .. , , .. . . , . .. ,, . . .. . . . . .. ,. . .. , . . ..... ... ... . . _,
amount of dysprosium iodide between 0.05 and 0.6 micromoles
per cubic centimeter is practical. When the amount of
dysprosium iodide sealed in the envelope 7a is outside this
range, the light output does not improve comspicuously.
Fig. 6 shows the dependence of the near ultraviolet
light output of the electrodeless lamp 7 upon the mércury
content of the fill material thereof. The argon gas was
sealed at fixed pressure of 100 torr as the starter gas, and
dysprosium in the fixed amount of 0.26 micromoles per cubic
centimeter was sealed in the envelope 7a as the lisht emi'tins
metal, together with mercury iodide in the fixed amount of
0.39 micromoles per cubic centimeter. The amounts of these
substances were fixed at these values, while the amount of
mercury sealed in the envelope was changed and the dependence
of the light output of the lamp 7 on the amount of mercury
was measured. Thus, in this experiment of Fig. 6, the fill
material comprised the elements dysprosium and iodine in the
fixed amounts of 0.26 and 0.78 micromoles per cubic centimeter,
respectively, and also a fixed amount of argon at a pressure
of 100 torr in the envelope 7a.
As shown in Fig. 6, the light output of the lamp 7
increases rapidly at first with an increase in the amount of
mercury sealed in the envelope 7a, and saturated when the
- 17 -
~lt~97~
amount of mercury is at about 50 micromoles per cubic centimeter.
The light output is substantially constant when the amount
of mercury is increased beyond about this value. The amount
of mercury in the range of from 5 to 55 micromoles is
practically feasible. The reason is that when the amount of
.. , . . , . . . . . . , . ................... . . .-- -- . - -
mercury is less than 5 micromoles per cubic centimeter, the
light output is not improved sufficiently, and, on the other
hand, when it exceeds 55 micromoles per cubic centimeter,
the light emission in the envelope 7a presents a striped
pattern and becomes unstable with fluctuation.
With regard to the iodine content in the fill
material, an amount thereof necessary to form sufficient
amount~of dysprosium iodide DyI3 should be sealed in the
envelope 7a. When the iodine is sealed in the envelope 7a
in the ~or~ of mercury iodide, the maximum amount of iodine
which can be sealed in is 1.25 mg, or 6.2 micromoles per
cubic centimeter. The reason of this is that when the
amount of iodine in the fill material exceeds this maximum
of 6.2 micromoles per cubic centimeter, the light emission
in the envelope 7a becomes uneven and the discharye within
the envelope 7a becomes unstable with fluctuations. Thus,
the amount of iodine in the fill material should not be less
than 0.15 micromoles per cubic centimeter, which is necessary
to form the minimum permissible amount of dysprosium iodide
of 0.05 micromoles per cubic centimeter, and not more than
6.2 micromoles per cubic centimeter. Further, it is preferred
that the amount of iodine measured in terms of moles per
cubic centimeter exceeds 3 times the amount of dysprosium
- 18 -
~ ~.7~372S
. .
measured in the same terms. Namely, it is preferable that
the-amount of iodine exceeds the amount--thereof which is~
~necessary to combine with all the dysprosium present in the
fill material.
Thus, in view of the experiments described above
and also in view of further experiments, we conclude as
- follows with regard to the fill materials of an electrodeless
discharge lamp which comprise a rare gas, mercury, a halogen,
and a metal selected from the group consisting of dysprosium,
holmium, thulium, scandium, and the mixtures thereof.
The fill material should comprise for each one
cubic centimeter of the content of the envelope, mercury in
an amount ranging from 5 to 55 preferably exceeding 17.5,
micromoles, a rare earth metal in an overall amount ranging
from 0.05 to 0.6 preferably from 0.13 to 0.39 and more
preferably around 0.25, micromoles, and halogen in an overall
amount ranging from 0.15 to 0.62 micromoles. It is preferred
that the amount of halogen measured in terms of micromoles
per one cubic centimeter of the volumetric content of the
envelope exceed three times the amount of the rare earth
metal measured in the same terms. That is, it is preferred
that there be enough halogen to combine with al1 the rare
earth metal present in the envelope to form the halide
thereof.
Referring to Fig. 7 of the drawings, a third
series of experiments is now described.
In the envelope 7a of the electrodeless discharge
lamp 7, a fill material was sealed which comprises mercury
- 19 -
3L~7972S
.
in the amount of 100 mg, iron in the amount of 0.3 mg, and
. .
argon as the rare gas at the pressure of 60 torr. The fill
material further comprised 3 mg of mercury iodide in the
first experimental example. In the second experimental
example, the fill material comprised 2 mg of mercury iodide
. . . - -- ~ ' ' ~ ' ' ~' ~ ~ ~ ' '~ ~-- --
nd 1 mg of mercury bromide. In the third experimental
example, the fill material comprised 1 mg of mercury iodide
and 2 mg of mercury bromide. In the fourth experimental
example, the fill material comprised 3 mg of mercury bromide.
Thus, in addition to the fixed amounts of mercury, iron, and
argon, all four examples comprised, mercury iodide and/or
mercury bromide in the fixed total amount of 3 mg, but in
variable mole fractions thereof. The lamp 7 was placed in
the microwave generating device of Fig. 1, and the light
output thereof in the near ultraviolet ~a~e lensth ranse of
350 to 450 nm and the starting time, i.e., the time required
by the lamp after it is turned on to attain 80 per cent of
the light output of stable light emission state thereof were
measured.
The abscissa in Fig. 7 represents the mole fraction
of bromine with respect to the total molar content of iodine
and bromine in percent, i.e.,
Ml
Ml + M2 X 100, ,
wherein Ml and M2 are the amounts of bromine and lodine
respectively, in terms of moles. The ordinate of Fig. 7
represents the light output of the lamp in an arbitary scale
and the starting time in seconds. The solid line T represents
the starting time and the dotted line P represents the light
output.
- 20 -
1~L797;~S
.
As shown in Fig. 7, the starting times of the lamp
- . . . . . ..
7 in the cases where the fill material comprises solely
iodine or bromine, respectively, are 13.5 and 1~.2 seconds.
The starting time is reduced when both bromine and iodine
are included in the fill material, and when the mole fraction
of bromine is chosen between 10 and 77.5 per cent, the
starting time is reduced under 10 seconds. The reason why
the starting time can be reduced by utilising two halogen
elements instead of only one is that the vapour pressure of
the halides of the light emitting metal comes to be the sum
of the vapour pressures of two kinds of halides of the
m~ ~1, and thus the appropriate vapour pressure of the
halides of the metal is reached at a time when the temperature
of the surface of the envelope 7a of the lamp 7 is lower
th~n that at the stable state thereof.
As shown further in Fig. 7, the light output in
the wave length range of 350 to 450 nm is increased when
both iodine and bromine are included in the fill material,
as compared to the case in which only iodine or bromine is
included. The light output of the lamp the fill material of
which includes only mercury as the light emitting metal was
31.0 in this arbitary scale, and thus the maximum light
output of the lamp used in this experiment scored 3.2 times
as much as that conventional lamp.
In the experiments described above, the light
emitting metal was iron, and the halogen iodine and bromine.
By further experiments, however, it was confirmed that the
starting time is reduced when combination of halogens other
- 21 -
1~7~372S
than bromine and iodine are used, i.e., when, for example,
- . . - . . .......................... . ...
the combination of iodine and chlorine, of bromine and
chlorine, or of iodine, bromine, and chlorine is used.
Further, the starting time of the lamp 7 is expected to be
reduced when light emitting metal other than iron is used.
.. .. ............ . . . . .... ..
.. . . . . . .
- ~2 -
~7~3725
Example I
. ,- - , , " , ~ ~
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprises iron in the amount of
0.5 mg or 0.63 micromoles per cubic centimeter, mercury
iodide (HgI2) in the amount of 4 mg, or 0.62 micromoles per
.. . . . . ............ . . . . . .
cubic centimeter, mercury in the amount of 118 mg, and argon
at the préssure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 120 mg, or 42.4 micromoles
per cubic centimeter. The amount of iodine in terms of
atoms was 1.24 micromoles per cubic centimeter which was
less than two times the amount of iron measured in the same
terms, by an amount of 0.02 micromoles per cubic centimeter. -
Namely, there was a shortage of 0.02 micromoles per cubic
centimetsr of iodine to combine with all the iron presen~ ln
the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 206 in
an arbitary scale, which is 4.12 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 17.0 seconds.
- 23 -
~ - -
1^.~79~725
.
.. .. .. . . .. . . . .. ..
Example II
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised palladium in the amount
of 1.0 mg, iodine in the amount of 4 mg, mercury in the
amount of 118 mg, and argon at the pressure of 100 torr.
.. . . . .
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 103 in
an arbitary scale, which is 2.1 times as much as that of the
lamp 7 the fll 1 material of whlch includes only mercury.
The startinq time on the other hand was 19.0 seconds.
- 24 -
- ~7972S
Example III
In the envelope 7a having the volumetrie eontent
of 14.1 eubie eentimeters of the lamp 7 of Fig. 2, the fill
material was sealed whieh comprised iron in the amount of
0.3 mg or 0.38 micromoles per eubie eentimeter, mereury
ioaide in the amount of 2.5 mg, or 0.3g mieromoles per eubie
eentimeter,..mereury in the amount of 99 mgi~ and--argon--at the~
pressure of 100 torr. Thus, the fill material eomprised
mereury in the total amount of 100 mg, or 35.3 mieromoles
per eubie eentimeter. The amount of iodine atoms was 0.78
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.01 micromoles per cubie eentimeter. Namely, there was an
excess of 0.01 micromoles per cubie centimeter of iodine to
com~ine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above w~s placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 196 in
an arbitary scale, which i.s 3.92 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 16.5 seconds.
- 25 -
:1~79~25
Example IV
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromol~s per cubic
centimer, mercury in the amount~of 98 mg, and argon at the
pressure of lO0 mg, or 35.3 micromoles per cubic centimer.
The amount of iodine atoms was 1.72 micromoles per cubic
centimer which exceeded two times the amount of iron measured
in the same terms, by an amount of 0.06 micromoles per cubic
centimeter. Namely, there was an excess of 0.06 micromoles
per cubic centimeter of iodine to combine with all the iron
present in the fill material.
The lamp 7 including 'he fill material as descriDea
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 216 in
an arbitary scale, which is ~.32 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 17.5 seconds.
- 26 -
~xample V
- In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
1.0 mg or 1.29 micromoles per cubic centimeter, mercury
iodide in the amount of 8.0 mg, or 1.24 micromoles per cubic
- , . . . :. . , ,, ,=., .
centimeter, mercury in the amount of 97 mg, and argon at the
pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35.3 micromoles
per cubic centimeter. The amount of iodine atoms was 2.48
micromoles per cubic centimeter which was less than two
times the amount of iron measured in the same terms, by an
amount of 0.08 micromoles per cubic centimeter. Namely,
there was a shortage of 0.08 micromoles per cubic centimeter
of iodine to combine with all the iron present in the fill
material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 210 in
an arbitary scale, which is 4.20 times as much as that o~
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 18.0 seconds.
- 27 -
1:1797~S
Example VI
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
1.5 mg or 1.91 micromoles per cubic centimeter, mercury
iodide in the amount of 12.0 mg, or 1.87 micromoles per
cubic centimeter, mercury in the amount of 95 mg, and argon -
at the pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35.3 micrornoles
per cubic centimeter. The amount of iodine atoms was 3.74
micromoles per cubic centimeter which was less than two
times the amount of iron measured in the same terms, by an
amount of 0.08 micromoles per cubic centimeter. Namely,
there was a shortage of 0.08 micromoles per cubic centimeter
of iodine to combine with all the iron present in the fill
material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 196 in
an arbitary scale, which is 3.92 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 18.0 seconds.
- 28 -
- - -
- ~17~3~25
Example VII
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 4.0 rng, or 0.62 micromoles per cubic
centimeter, mercury in the amount of 98 mg, and argon at the
pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35.3 micromoles
per cubic centimeter. The amount of iodine atoms was 1.24
micromoles per cubic centimeter which was less than two
times the amount of iron measured in the same terms, by an
amount of 0.42 micromoies per cubic centimeter. Namely,
there was a shortage of 0.42 micromoles per cubic centimeter
of ioaine to combine with all tne iron preseni in ine fill
material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 206 in
an arbitary scale, which is 4.12 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 17.0 seconds.
- 29 -
~ ~.7~3725
Example VIII
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 7.0 mg, or 1.10 micromoles per cubic
centimeter, mercury in the amount of 97 mg, and argon at the
pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, 35.3 or micromoles
per cubic centimeter. The amount of iodine atoms was 2.20
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.54 micromoles per cubic centimeter. Namely, there was an
excess of 0.54 micromoles per cubic centimeter of iodine to
comblne with all the iron present in the fill material.
The lamp 7 including the fili material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 210 in
an arbitary scale, which is 4.2 times as much as that of the
lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 16.5 seconds.
- 30 -
9~25
Example IX
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 10.0 mg, or 1.56 micromoles per
cubic centimeter, mercury in the amount of 96 mg, and argon
at the pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35.3 micromoles
per cubic centimeter. The amount of iodine atoms was 3.12
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.73 micromoles per cubic centimeter. Namely, there was an
excess of 0.73 micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range-of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 206 in
an arbitary scale, which is 4.12 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 15.0 seconds.
- 31 -
9725
., ,
~xample X
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 15.0 mg, or 2.34 micromoles per
cubic centimeter, mercury in the amount of 93 mg, and argon
at the pressure of lOOtorr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35 . 3 micromoles
per cubic centimeter. The amount of iodine atoms was 4.68
micromoles per cubic centimeter which exceeded two times the
a~lou~t of iron measured in the same terms, by an amount of
3.01 micromoles per cubic centimeter. Namely, there was an
excess of 3.01 micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave lcngth range of 35b to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 190 in
an arbitary scale, which is 3.80 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 15.0 seconds.
- 32 -
1~'79~725
Example XI
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2,the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromoles per cubic
centimeter, mercury in the amount of 48 mg, and argon at the
pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 50 mg, or 17.6 micromoles per
cubic centimeter. The amount of iodine atoms was 1.72
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.06 micromoles per cubic centimeter. Namely, there was an
excess 0.06 of micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 203 in
an arbitary scale, which is 4.06 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 13.0 seconds.
- 33 -
79725
Example XII
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the ~ill
material was sealed which compried iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromoles per cubic
centimeter, mercury in the amount of 68 mg, and argon at the
pressure of lO0 torr. Thus, the fill material comprised
mercury in the total amount of 70 mg, or 24.7 rnicromoles per
cubic centimeter. The amount of iodine atoms was 1.72
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.06 micromoles per cubic centimeter. Namely, there was an
excess of 0.06 micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
4~5 nm and the starting time, i.e.~ the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 212 in
an arbitary scale, which is 4.24 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 16.0 seconds.
- 34 -
~9725
Example XIII
In the envelope 7a having the volumetric conten~
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromoles per cubic
centimeter, mercury in the amount of 88 mg, and argon at the
pressure of lO0 torr. Thus, the fill material comprised
mercury in the total amount of 90 mg, or 31.8 micromoles per
cubic centimeter. The amount of iodine atoms was 1.72
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.06 micromoles per cubic centimeter. Namely, there was an
excess of 0.06 micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
l, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 215 in
an arbitar~ scale, which is 4.30 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 17.5 seconds.
- 35 -
lI~7~7Z5
Example XIV
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromoles per cubic
centimeter, mercury in the amount of 98 mg, and argon at the
pressure of 20 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35.3 micromoles
per cubic centimeter. The amount of iodine atoms was 1.72
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.06 micromoles per cubic centimeter. Namely, there was an
excess of 0.06 micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 220 in
an arbitary scale, which is 4.4 times as much as that of the
lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 22.0 seconds.
- 36 -
~1797Z5
Example XV
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromoles per cubic
centimeter, mercury in the amount of 98 mg, and argon at the
pressure of 40 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35.3 micromoles
per cubic centimeter. The amount of iodine atoms was 1.72
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.06 micromoles per cubic centimeter. Namely, there was an
excess of 0.06 micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time/ i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 218 in
an arbitary scale, which is 4.36 times as much as that of the
lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was l9.S seconds.
- 37 -
:~17972~
Example XVI
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromoles per cubic
centimeter, mercury in the amount of 98 mg, and argon at the
pressure of 80 torr. Thus, the fill material comprised
mercury in the total amount o~ 100 mg, or 35.3 per cubic
centimeter. The amount of iodine atoms was 1.72 micromoles
per cubic centimeter which exceeded two times the amount of
iron measured in the same terms, by an amount of 0.06 micromoles
per cubic centimeter. Namely, there was an excess of 0.06
micromoles per cubic centimeter o~ iodine to combine with
all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 216 in
an arbitary scale, which is 4.32 as much as that of the lamp
7 the fill material of which includes only mercury. The
starting time on the other hand was 18.0 seconds.
- 38 -
~ ~79725
Example XVII
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromoles per cubic
centimeter, mercury in the amount of 98 mg, and argon at the
pressure of 120 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35.3 micromoles
per cubic centimeter. The amount of iodine atoms was 1.72
micromoles per cubic centimeter which exceeded two times the
amount of iron measured in the same terms, by an amount of
0.06 micromoles per cubic centimeter. Namely, there was an
excess of 0.06 micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
~ho~e was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm an~ the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 214 in
an arbitary scale, which is 4.28 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 16.0 seconds.
- 39 -
~ ~797~5
Example X~III
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the ~ill
material was sea;ed which comprised iron in the amount of
0.65 mg or 0.83 micromoles per cubic centimeter, mercury
iodide in the amount of 5.5 mg, or 0.86 micromoles per cubic
centimeter, mercury in the amount of 98 mg, and argon at the
pressure of 150 torr. Thus, the fill material comprised
mercury in the total a unt of 100 mg, or 35.3 micromoles
per cubic centimeter. The amount of iodine atoms was 1.72
micromoles per cubic centimeter which exceeded two times the
amD~nt of iron measured in the same terms, by an amount of
0.06 micromoles per cubic centimeter. ~Namely, there was an
excess of 0.06 micromoles per cubic centimeter of iodine to
combine with all the iron present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range o~ 350 to
425 nm ar.d the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stab~e state light emission, were measured. The light
output thus measured during the stable state scored 213 in
an arbitary scale, which is 4.26 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 16.0 seconds.
- 40 -
1~L7'~7~S
Example XIX
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised dysprosium in the amount
of 0.6 mg or 0.26 micromoles per cubic centimeter, mercury
iodide in the amount of 4.0 mg, or 0.62 micromoles per cubic
centimeter, mercury in the amount of 118 mg, and argon at
the pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 120 mg, or 42.4 micromoles
per cubic centimeter. The amount of iodine in terms of
atoms was 1.24 micromoles per cubic centimeter which exceeded
thre~ times the amount of dysprosium measured in the same
terms, by an amount of 0.46 micromoles per cubic centimeter.
Namely, there was an excess of 0.46 micromoles per cubic
centimeter of iodine to combine with all the dysprosium
present in the fill material.
The lamp 7 including the fill material as described
above was place~ in the microwave generating device of Fig.
1, an~ the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 186 in
an arbitary scale, which is 3.72 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 22.0 seconds.
:~1797~S
Example XX
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised scadium in the amount of
0.3 mg, mercury iodide in the amount of 4 mg, mercury in the
amount of 118 mg, and argon at the pressure of 100 torr.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 152 in
an arbitary scale, which is 3.04 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 20.0 seconds.
- 42 -
-~l'79~2S
Example XXI
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised dysprosium in the amount
of 0.3 mg or 0.13 micromoles per cubic centimeter, mercury
iodide in the amount of 2.0 mg, or 0.31 micromoles per cubic
centimeter, mercury in the amount of 119 mg, and argon at
the pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 120 mg, or 42.4 micromoles
per cubic centimeter. The amount of iodine atoms was 0.62
micromoles per cubic centimeter which exceeded three times
the amount of dysprosium measured in the same terms, by an
arnount of 0.23 micromoles per cubic centimeter. Namely,
there was an excess of 0.23 micromoles per cubic centimeter
of iodine to combine with all the dysprosium present in the
fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1~ and the light output in the wave length range of 350 to
425 nm ~lld the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 162 in
an arbitary scale, which is 3.24 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 22.0 seconds.
- 43 -
2S
Example XXII
In the envelope 7a having the volumetrie content
of 14 .1 cubic centimeters of the lamp 7 of Fig. 2, the f ill
material was sealed which comprised dysprosium in the amount
of 0. 9 mg or 0.39 micromoles per cubic centimeter, mercury
iodide in the amount of 4.0 mg, or 0.62 micromoles per cubie
centimeter, mercury in the amount of 118 mg, and argon at
the pressure of 100 torr. Thus, the fill material comprised
mereury in the total amount of 120 mg, or 42.4 micromoles
per eubie eentimeter. The amount of iodine atoms was 1.24
mieromoles per cubic centimeter which exceeded three times
the amount of dysprosium mesasured in the same terms, by an
amount of 0. 07 micromoles per cubic centimeter. Namely,
there was an excess of 0. 07 micromoles per cubic centimeter
of iodine to combine with all the dysprosium present in the
fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 144 in
an arbitary scale, which is 2.88 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 17.0 seconds.
- 44 -
~7~7ZS
Example XXIII
In the envelope 7a having the volumetrie eontent
of 14.1 eubie eentimeters of the lamp 7 of ~ig. 2, the fill
material was sealed whieh eomprised dysprosium in the amount
of 1.2 mg or 0.52 micromoles per cubic centimeter, mercury
iodide in the amount of 6.5 mg, or 1.015 micromoles per
eubie eentimeter, mercury in the amount of 117 mg, and argon
at the pressure of 100 torr. Thus, the fill material comprised
mereury in the total amount of 120 mg, or 42.4 mieromoles
per cubic centimeter. The amount of iodine atoms was 2.03
mieromoles per eubie eentimeter which exeeeded three times
the amount of dysprosium measured in the same terms, by an
amount of 0.47 micromoles per cubic centimeter. Namely,
there was an excess of 0.47 micromoles per cubic centimeter
of iodine to combine with all the dysprosium present in the
fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the l~mp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 96 in an
arbitary scale, whieh is 1.92 times as much as that of the
lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 15.5 seconds.
- ~5 -
79725
Example XXIV
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised dysprosium in the amount
of 0.6 mg or 0.26 micromoles per cubic centimeter, mercury
iodide in the amount of 4.0 mg, or 0.62 micromoles per cubic
centimeter, mercury in the amount of 48 mg, and argon at the
pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 50 mg, or 17.6 micromoles per
cubic centimeter. The amount of iodine atoms was 1.24
micromoles per cubic centimeter which exceeded three times
the amount of dysprosium measured in the same terms, by an
amount of 0.46 micromoles per cubic centimeter. Namely,
there was an excess of 0.46 micromoles per cubic centimeter
of iodine to combine with all the d~sprosium present in the
fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The liyht
output thus measured during the stable state scored 162 in
an arbitary scale, which is 3.24 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 15.0 seconds.
- - ~6 -
1~7'~7~C;
Example xxV
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised dysprosium in the amount
of 0.6 mg or 0.26 micromoles per cubic centimeter, mercury
iodide in the amount of 4.0 mg, or 0.62 micromoles per cubic
centimeter, mercury in the amount of 73 mg, and argon at the
pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 75 mg, or 26.5 micromoles per
cubic centimeter. The amount of iodine atoms was 1.24
micromoles per cubic centimeter which exceeded three times
the amount of dysprosium measured in the same terms, by an
amount of 0.46 micromoles per cubic centimeter. Namely,
there was an excess of 0.46 micromoles per cubic centimeter
of iDdine to combine with all the dysprosi~m present in the
fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and th~ light output in the wave length range of 350 to
425 nm ~nd the starting time, i.e., the length of time that
~he lalllp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 170 in
an arbitary scale, which is 3.4 times as much as that of the
lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 18.0 seconds.
- 47 -
~7972S
Example XXVI
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. Z, the fill
material was sealed which comprisea dysprosium in the amount
of 0.6 mg or 0.26 micromoles per cubic centimeter, mercury
iodide in the amount of 4.0 mg, or 0.62 micromoles per cubic
centimeter, mercury in the amount of 98 mg, and argon at the
pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 100 mg, or 35.3 micromoles
per cubic centimeter. The amount of iodine atoms was 1.24
micromoles per cubic centimeter which exceeded three times
the am~unt of dysprosium measured in the same terms, by an
amount of 0.46 micromoles per cubic centimeter. Namely,
there was an excess o~ 0.46 micromoles per cubic centimeter
of iodine to combine with all the aysprosium present in the
fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 182 in
an arbitary scale, which is 3.64 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 22.0 seconds.
- 48 -
7ZS
Example XXVII
In the envelope 7a having the volumetrie content
of 14.1 cubie centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which cornprised dysprosium in the amount
of 0.6 mg or 0.26 micromoles per cubic centimeter, mercury
iodide in the amount of 4.0 mg, or 0.62 micromoles per cubic
centimeter, mercury in the amount of 148 mg, and argon at
the pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 150 mg, or 53.0 micromoles
per cubic centimeter. The amount of iodine atoms was 1.24
micromoles per cubic centimeter whieh exceeded three times
the amount of dysprosium measured in the same terms, by an
amount of 0.46 micromoles per cubie eentimeter. Namely,
thexe was an excess of 0.46 micromoles per cubic centimeter
of iodine to eombine with all the dysprosium present in the
fill material.
The lamp 7 including the fill material as described
above was plaeed in the microwave generating deviee of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 194 in
an arbitary scale, which is 3.88 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 23.0 seconds.
- 49 -
~ 3
Example XXVIII
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised dysprosium in the amount
of 0.6 mg or 0.26 micromoles per cubic centimeter, mercury
iodide in the amount of 2.0 mg, or 0.31 micromoles per cubic
centimeter, mercury in the amount of ll9 mg, and argon at
the pressure of lO0 torr. Thus, the fill material comprised
mercury in the total amount of 120 mg, or 42.4 micromoles
per cubic centimeter. The amount of iodine atoms was 0.62
micromoles per cubic centimeter which was less than three
times the amount of dysprosium measured in the same terms,
by an amount of 0.16 micromoles per cubic centimeter.
Namely, there was a shortage of 0.16 micromoles per cubic
centimeter of iodine to combine with all the dysprosium
present in the fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
l, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state~scored 183 in
an arbitary scale, which is 3.66 times as much as that of
the lamp 7 the fili material of which includes only mercury.
The starting time on the other hand was 22.0 seco~ds.
- 50 -
li'79725
Example XXIX
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised dysprosium in the amount
of 0.6 mg or 0.26 micromoles per cubic centimeter, mercury
iodide in the amount of 6.0 mg, or 0.935 micromoles per
cubic centimeter, mercury in the amount of 117 mg~ and argon
at the pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 120 mg, or 42.4 micromoles
per cubic centimeter. The amount of iodine atoms was 1.8 7
micromoles per cubic centimeter which eY.ceeded three times
the amount of dysprosium measured in the same terms, by an
amount of 1. 35 micromoles per cubic centimeter. Namelyj
there was an excess of 1. 35 micromoles per cubic centimeter
of iodine to combine with all the dysprosium present in the
fill material.
The lamp 7 including the fill material as described
above was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 186 in
an arbitary scale, which is 3.72 times as much as that of
the lamp 7 the fill material of which includes only mercury.
The starting time on the other hand was 22.0 seconds.
-- 51 --
~7~725
Example xxx
In the envelope 7a having the volumetric content
of 14.1 cubic centimeters of the lamp 7 of Fig. 2, the fill
material was sealed which comprised dysprosium in the amount
of 0.6 mg or 0.26 micromoles per cubic centimeter, mercury
iodide in the amount of 12.0 mg, or 1.875 micromoles per
cubic centimeter, mercury in the amount o 115 mg, and argon
at the pressure of 100 torr. Thus, the fill material comprised
mercury in the total amount of 120 mg, or 42.4 micromoles
per cllbic centimeter. The amount of iodine atoms was 3.75
micromoles per cubic centimeter which exceeded three times
the amount of dysprosium measured in the same terms, by an
amount of 2.97 micromoles per cubic centimeter. Namely,
there was an excess of 2.97 micromoles per cubic centimeter
of iodine to combine with all the dysprosium present in the
fill material.
The lamp 7 including the fill material as described
abbve was placed in the microwave generating device of Fig.
1, and the light output in the wave length range of 350 to
425 nm and the starting time, i.e., the length of time that
the lamp 7 required to attain 80 percent light emission of
the stable state light emission, were measured. The light
output thus measured during the stable state scored 160 in
an arbitary scale, which is 3.2 times as much as that of the
lamp 7 the f ill material of which includes only mercury.
The starting time on the other hand was 22.0 seconds.
- 52 -
72~
In the examples described above, examples I and
III through XVIII relates to the case in which the fill
material comprises iron as the light emitting metal, and
examples XIX and XXI through XXX to the case in which the
fill material comprises dysprosiurn as the light emitting
metal.
In the examples I and III through VI, the iron
content of the fill material was changed, and iodine was
included in the fill material in the form of mercury iodide
(HgI2), in the amount substantially sufficient to combine
with all the iron present in the fill material to form iron
iodide (FeI2). Namely, when the lamp is excited by the
microwave and turned on, the ioaine contained in the mercury
iodide reacts with iron and forms iron iodide. When the
iron iodide thus formed ranges from 0.38 to 1.91 micromoles
per cubic centimter, the light output scored not less than
90 percent of the maximum light output attainable (example
XIV) in the case in which the fill material comtains iron as
the light emitting metal.
In the examples I and VII through X, the content
of iron was fixed, while that of mercury iodide was varied
so that the amount of iodine varied frorn the cases in which
there was a shortage of iodine to combine with all the iron
present, to the cases in which there was an axcess of iodine
to combine with all the iron present. When the excess
amount of iodine in terms of atoms is not more than 2.0
micromoles per cubic centimer, the light outputs not less
than gO percent of the maximum light output were scored.
- 53 -
1179725
When the amount of iodine is less than the amount thereof
sufficient to combine with all the iron present in the fill
material, there remains the metallic iron, as the amount of
iron iodide formed is limited by the amount of iodine present
in the fill material. In this case, the light output is
proportional to the amount of iron iodide formed in the
envelope 7a, and the inner surface of the envelope 7a formed
of quart~ of the lamp 7 tends to lose transparency in less
operation time thereof than in the case in which an excess
iodine is present. Thus, the preferred amount of iodine in
excess of the amount necessary to combine with all the iron
pr~sent in the fill material is from 0.02 to 0.2 micromoles
per cubic centimeter of the volumetric content of the envelope
7a.
In the examples XI through XIII, the contents of
irQn ~nd mercury iodide in the fill material were fixed,
while that of mercury was changed. When the amount of
mercury in the fill material was from 17.6 to 4i.3 micromoles
per cubic centimeter, the light output of the lamp 7 scored
not less than 90 percent of the maximum light output attainable
in the cas~ in which the fill material includes iron as the
light emitting metal.
In the exarnples I and XIV through XVIII, the
contents of iron, mercury iodide, and mercury in the fill
material were fixed, while the pressure of argon was changed.
When the pressure of argon was from 20 to 150 torr, the
light output of the lamp 7 was not less than 95 percent of
the maximurn light output attainable in the case in which the
- 54 -
-~79725
light emitting metal is iron, which maximum is attained in
example XIV. In example XIV, however, the discharge in the
envelope 7a tended to be extinguished before it reaches the
stable state of light emission. It was found that the
preferred pressure of argon in the envelope 7a was from 30
to 130 torr.
In the examples XIX and XXI to XXIII, dysprosium
content was varied, while iodine in the form of mercury
iodide was sealed in the envelope 7a in an amount sufficient
to combine with all the dysprosium present in the fill
material. When the amount of dysprosium was not less than
0.13 micromoles per cubic centimeter and not more than 0.39
micromoles per cubic centimeter, the lamp 7 scored not less
than about 70 percent of the maximum light output attainable
in the case in which the fill material included dysprosium
as the light emitting metal.
In the examples XIX, and XXIV through XXVII, the
dysprosium and the mercury iodide contents were fixed, while
the me~ ry content was varied. When the amount of mercury
in the fill material is from 17.6 to 53.0 micromoles per
cubic centimeter, then the lamp 7 scored not less than about
80 percent of the maximum light output attainable in the
case in which the fill material comprised dysprosium as the
light emitting metal.
In the examples XIX and XXVIII through XXX, the
amount of dysprosium and the total amount of mercury were
fixed, while the excess amount of iodine was varied. These
examples also scored not less than 80 percent of the maximum
- 55 -
~ ~797ZS
light output attainable in these cases. When the mercury
iodide content was less than the amount which contains
sufficient amount of iodide to combine with all the dysprosium
present in the fill material, i.e., when an excess amount of
dysprosium is present with respect to the amount of iodine,
the envelope 7a formed of quartz lost transparency thereof
in a shorter operational time than in the case in which
iodine is sealed in excess with respect to the amount of
dysprosium. Thus, it is preferred that iodine is sealed in
excess of the amount necessary to combine with all the
dysprosium present in the fill material.
