Note: Descriptions are shown in the official language in which they were submitted.
115707~3
.
EL~CT~IC FLASH APPARA~'US
The present invention relates to a flash apparatus, and
more particularly to an electrlc ~lash apparatus.
BACKGROUND 0~ THE INV~NTION
In recent years, the flash apparatus has been widely em-
ployed in various kinds of optical apparatus which requires
light o~ the ~lash. Particularly, in the art of photography,
artificial light is used to illuminate an object to be photo-
graphed. One form of arti~icial light which into wide use is
so-called electric ~laæh device. In such devices, a flash tube
iæ provided in order to illuminate the object to be photographed.
l`he light from the ~lash tube can only be used to illuminate
the object to take a picture. When the ~lash light ~rom a
photoflash is used to illuminate the object to be photographed,
light and darkness appear on the photographic object in case
there is unevenness on the sur~ace of the photographic object.
~urthermore, when the ~lash light ~rom the photoYlash is em-
ployed as a direct-light for illuminating the photographic
object in a room or a photostudio, æhadow of the photographic
object is ~ormed behind thereof and it is, there~ore, not so
pre~erable to take a picture in a practical use.
In order to eliminate the disadvantages of the photo~lash
device, it ks known to take a picture by using means for gene-
rating bounce light. In taking a plcture by means of the
bounce light, there are, however, still disadvantages that
quantity of the light incidenting on the photographic object
iæ lowered compared with the predetermined value particulatly
when a re~lecting æurface such aæ a surface of celling is not
~,i
7~'7~3
so white, and that the photographic object can not be photo-
graphed so good when there is the unevenness on the surface
of the object to be photographed, because the reflected
light from the object does not, in part, incident on a film
of a camera.
To eliminate the above disadvantages, required
are various kinds of high price devices such as, for example,
a front light, an umbrella-shaped bounce light and a
backlight for removing the shadow appearing at the background
of the photographic object. This results in a package which
is sufficiently bulky as to preclude its use in portable, as
well as is costly and lmeconomical.
In accordance with a particular embodiment of the
invention there is provided an electric flash apparatus.
The apparatus has a circuit for charging a main capacitor
and a flash tube circuit actuated by the operation of a
trigger circuit when an electric charge is stored on the main
capacitor. Also provided are a plurality of flashing members,
each of which includes at least one flash tube, and a flash
control circuit arrangement for receiving light generated
from the flashing members and reflected from an object to be
photographed. The flash control circuit also converts the
light to an electric energy and automatically controls
flash-light quantity when the electric energy attains a
predetermined value. The flashing members comprise a first
flashing member adaptable to generate direct light with
respect to the object to be photographed and a second flash-
ing member adapt~ble to generate indirect light with respect
to the object. Means are provided for making the incident
direction of the second flashing member adjustable and means
~ - 2 -
;
~57V7B
are provided for adjusting flash light quantity such that
the flash light quantity of the first flashing member is
less than that of the second flashing member when the first
and second flashing members activate.
;' `''
~1570~8
BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is a detailed circuit diagram of a control circuit
arrangement of an electric flash apparatus according to the
present invention;
Fig. 2 is a schematic view of an electric flash apparatus
in accordance with the present invention;
~ig. 3 is an elevational-side view for explaining an oper-
ation, when a bounce photographing is performed by using an
electric flash apparatus in accordance with the present in-
vention; -
Fig. 4 is a graph æhowing a characteristic o~ the
quantity of light produced from an electric flash apparatus in
accordance with the present invention; and
Fig. 5 is a graph showing a characteristic o~ the quantity
of light and denoting an operation oi an electric ~lash appa- ;~
ratus according to the present invention.
DESCRIPTION OF THE PXEFERED EMBODIME~T OF THE INVENTION
Referring to Fig. 1 of the drawing, there is shown a
greatly simplified electric flash apparatus in accordance with
the present invention. The electric flash apparatus has a
flash housing, generally designated by numeral 10 which consists
of a first casing 11 and a second casing 12. The second casing ;
12 is pivotably connected to the iirst casing 12 by means of a
connecting member 14. ~he connecting member 14 is constructed
by a conventional ratch mechanism. The ratch mechanism is con-
structed by a pin 14a which is fixed on the second casing 12 and
which is pivotably engaged with the first casing 11, a ratch
gear 14b which is fastened to the second casing 12 together
with the pin 14a, a curved U-shaped plate spring 14c inserted
~57~78
into the first casing 11 and a enga~ing segment 14d which is
provicled between the plate spring 14c and the ratch gear 14a.
Accorclingly, the second casing 12 is rotatable as is shown by
an arrow 13 with respect to the ~irst casing 11. The ~irst
5 casing 11 is equipped with a light sensitive element 15 and a
~irst Plashin~ member 16 which includes a ~irst flash tube 17,
on a surface thereo~. The second casing 12 is also equipped
with a second flashin~ member 18 which includes a second flash
tube 19. Accomodated in the i'lash housing 10 is a flash con-
trol circuit arrangemellt which is constructed a~ shown in ~ig. 2.
As is best shown in Fig. 2, the flash control circuitarrangement comprises a power source circuit A, a electric
charge Etoring circuit B for supplying the electrical energy to
the ~lash tubes 1~ and 19, a trigger pulse generating circuit C
~or trig~ering the flash tube member, a ~lash tube circuit ~
~or generating a flash light, a switching circuit D for actua-
tin$ the ~lash tube circuit E, a quenching circuit F for ex-
tinguishing the flash tubes o~ the ~lash tube circuit E, a
quench trig~er si~nal generating circuit G for actuating the
quenching circuit F and a light-sensitive circuit H ~or actua-
ting the quench trigger si~nal generating circuit F.
In more detail, the power ~ource circuit A include~ a
battery 20, a manually operated switeh 21 and a resistor 22 con-
nected in series with the battery 20 by way of the switch 21.
The electric charge storin~ circuit B comprises a main ~torage
eapacitor 23 which i~ connected in parallel relationship to the
battery 20 through the switch 21 and the resistor 22 and a charg-
ing level indicating lamp in the form of a neon tube 25 which i9
conneeted in parallel with the main storage capacitor across a
resistor 25. When the main storage capacitor 23 is c~arged up
~lS7~78
to a predetermined charging voltage, the neon tube 25 lumi-
nesces and indicates the ready for flashing.
The trigger pulse generating circuit C includes a
trigger resistor 26, a trigger capacitor 27 and a trigger
transformer 28. In the trigger pulse generating circuit C,
one terminal of the trigger resistor 26 is connected to a
positive terminal of the battery 20 by way of the resistor
22 and the switch 21, One terminal of the trigger capacitor
27 is connected to the other terminal of the resistor 26 and
an input winding 28a of the trigger transformer 28 is con-
nected to the other terminal of the trigger capacitor 27,
The switching circuit D includes a trigger capacitor
29, a transformer 30, a synchronizing switch 31 and a switch-
ing element in the form of a first thyristor 32, a protecting
resistor 33, a gate resistor 34, a capacitor 35 and a resistor
36. The trigger capacitor 29 is connected to the trigger
resistor 26, and an input winding 30a of the pulse trans-
former 30 is connected between the input winding 28a and
capacitor 29. The synchronizing switch 31 is interposed
between a juncture of the resistor 26 and the capacitor 27
and a juncture of the input windings 28a and 30a. The pro-
tecting resistor 30 is interconnected between a negative
terminal of the battery 20 and a juncture of the synchronizing
switch 31 and the input winding 30a of the pulse transformer
30, An output winding 30b of the pulse transformer 30 is
connected between a gate electrode and a cathode electrode
of the first thyristor 32 through the gate resistor 34. The
switch 31 is mounted on a camera, and is closed in syn-
chronism with a camera shutter opening operation, enabling
flash tube to be fired by the well-known operation of flash
trigger circuit,
5 -
1157078
The flash tube circuit ~ comprises a first ilash tube 1'7,
a second ilash tube 19 and a current-limitting resistor 37 ~or
restrictin~ flash current ilowing the iirst flash tube ~7.
The first ilash tube 17 is provided with a pair of rnain
current conducting electrode 17a, 17b and a trigger electrode
17c which is positioned adjacent but external to the ilash tube
17. The second flash tube 19 is al~o provided with a pair of
main current conducting electrodes l9a, l9b and a triggeI elec-
trode l9c which is also positioned adjacent but external to the
flash tube 19. As explained in the foregoing in Fig. 1, the
first flash tube 1'7 is arranged in the iirst ilashirlg menlber 16
which is mounted on the surface o~ the iirst casing 11, and the
second ilash tube 19 is arranged in the second flashing member
18 mounted on an end portion o~ the second cas~ng 12. One main
current conducting electrode l9a of the second flash tube 19 is
connected to one electrode of the main storage capacitor 23, and
the other main current conducting electrode l9b iB connected to
an anode electrode oi the thyristor S2 oi the switching circuit
D. The trigger electrode l9c of the second flash tube 19 is
connected to one terminal of an output winding 28b oi trigger
transformer 28. One main current conducting electrode 17a is
connected to the one electrode of the main storage capacitor 23
through the current-limitting re~istor 37, and the other main
current conductlng electrode 17b ls connected -to the anode oi
the thyristor -S2 together with the main current conducting
electrode l9b oi the second ilash tube 19 and, thereiore, the
electrode 17b and l9b are connected t~, th~ othe~ electrode o~
the main storage capacitor 2~ by way oi the f~r~ th.y~ 2.
.. 'rhe trigger electrode 17c of the Yir~t fla~æh tube 17 is connec
to the output winding 28b O~ e ~F1gger trans~ormer 28
r .
.
~lS7~1~8
together with the trigger electrode l9c of the second flash .:
tube 19, thence the first flash tube 17 and the second flash
tube 19 are simultaneously triggered by the triggering signal
from t.he triggering pulse generating circuit C.
T.here are certain criteria, in the flash tube circuit ~,
that must be met in both flash tubes 17 and 19. To operate
ef~ectively, the current to be supplied to the first fla~h tube
17 mu~t be a relatively low value compared with that to be sup-
plied to the second flash tube 19, in order to make the quanti~
of the flash light generated from the ~irst flash tu~e 17 to
smaller than that of the flash light from the second flash tube
19. 'l`o perform this requisition, the firæt flash tube 17 must
have a relatively low impedance compared with the second flash
tube 19. To provide such low impeda~ce, the first flash tube
l'j 17 should have a low gass pressure and a short electrode spacing.
On the other hand, when the ~ir~t ~lash tube 17 has a low im-
pedance compared with the second ~lash tube 19, an initiation of ~ :
flashing of the first flash tube 17 occurs earlier than that of
the second flash tube 19. To supply such low current and to
adjust the flash durations of the flash tubes 17 and 19, thecurrent-limitting resistor 37 is connected to the ~irst flash
tube 17. Additionally, although the flash tube ci~cuit ~ em-
ploys the resistor 37 a~ the current-limittin~ element, the in-
vention is not limitted to thi~, and a chorked-coil ~ay also be ~:
employed.
The quenching circuit F includes a quench tube 38 for
qu~nching the fiash tubes 17 and 19, a resistor 39, a commu-
tation capacitor 40 and a commutation resistor 41. The quench
tube 38 is connected to both electrodes of the main stGra~e
capacitor 23 through the resistor 39. The commutation capaci-
-- 7 --
, -
,
. . , . :. ~ .
.
~L15'7~)78
tor 40 is connected between a juncture of the resistor 39 and
the quench tube 38 and the anode electrode of the thyristor 32,
and the commutation resistor 40 is connected in parallel relation-
ship to the thyristor 32 between the anode electrode and the
cathode electrode thereof.
There are, of couræe, certain criteria that must be met in
quench tube 38. To operate effectively, the quench tube 38
must have a ~urther low impedance compared with the second flash
tube 19. The second flash tube 19 has a minimum impedance o~
typically 1.5 to 2 oh~s. Thus, the quench tube 38 should have
an impedance near 0.~ oh~. To provide such low impedance, the
quench tube 38 also should have a low gass pressure and a short
electrode spacing. '~he electrodes 38a and 38b must be capable
o~ carrying a very high current for short time. The tube 38
must be capable o~ bei~g triggered rapidly and easily into con-
duction over the range which voltage of the ~lash -tubes 1'7 and
19 changes during the flash. The quench tube includes a trigger
electrode 38c spaced midway between the two main electr~des
38a and 38b.
The quench trigger signal generating circuit G comprises
a qugnch trigger transformer 42, two series connected resistors
3 and 44, a second switching element in the form of ~he thy-
ristor 45 whose anode electrode i9 connected an lnput winding
42a o~ the quench trans~ormer 42, and a quenching capacitor 46
which is co~nected in parallel with the re3istor 44. An ou~put
winding 42b of the quenching transformer 42 is interconnected
be-tween the trigger electrode 38c of the quench tube 38 and a
juncture of the input winding and the anode electrode o-f the
thyristor 45.
The li~ht sensitive circuit ~ comorises a light sensitive
-- 8 --
~'7~)'78
element in the form of a phototransistor 47, a capacitor 48
whose one electrode is connected to the positive electrode of
the battery 20, a zener diode 49 connected between the capaci-
tor ~8 and the photocell 47, a gate resistor 50 connected a
gate electrode of the thyristor 45 and the photocell 47, paral-
lelly connected resistor 51 and capacitor 52, and a protecting
resistor 53.
A circuit constructed in accordance with the fore-
going description operates as follows:
When the switch 21 is closed, the electric charge is
stored on the main storage capacitor 23 from the battery 20 by
way of the switch 21 and the resistor 23. Simultaneously the
triggering capacitors 27 and 29 are charged from the battery
20 through the trigger resistor 26. The electric charge is also
accumulated on the capacitors 40, 46 and 48 from the battery 20.
In thus conditions, the operation of the flash tube circuit E is
initiated by the closing of switch 31 of the switching circuit
D in synchronism with the camera shutter opening operation,
enabling flash tubes 17 and 19. When the switch 31 is closed,
the electric charge of the trigger capacitor 27 is discharged
through the switch 31 and the input winding 28a of the trigger
transformer 28, and the electric charge of trigger capacitor 29
is simultaneously discharged through the switch 31 and the in-
put winding 30a of the trigger transformer 30. By the discharge
of capacitor 26, a triggering pulse is generated from the out-
put winding 28b of the trigger transformer 28. And, at the
same, a gating pulse appears from the input winding 30b of the
pulse transformer 30, by discharging of the capacitor 29.
The stored voltage on the main storage capacitor 23
also appears across the electrodes 17a and 17b of the first
fla~h
h
llS7S)'78
tube 17 and across the l9a and l9b of the second flash tube 19.
The triggering pulse from the output winding 28b of
the trigger transformer 28 is applied to the trigger electrodes
17c cmd l9c of the tubes 17 and 19. The firing pulse from the
output winding 30b of the trigger transformer 30 is applied to
the gate electrode of the first thyristor 32 and the thyristor
32 is turned on. When the thyristor 32 becomes conductive, the
first flash tube 17 initiates a flash discharge between the
electrodes 17a and 17b, and, at the same time the second flash
tube 19 also initiates a flash between the electrodes l9a and
l9b, because each trigger electrode 17c and l9c is commonly
connected to the output winding 28b of the trigger transformer
28. Under normal operations heretofore, the flash continues
until the main storage capacitor 23 has discharged through the
tubes 17 and 19 to the point where the voltage will no longer
support the flash across the tubes 17 and 19. That usually
requires about several millisecond of time.
The light sensitive circuit H senses the flash light
from the tubes 17 and 19, and automatically adjusts the maximum
time duration of the flash produced across the tubes 17 and 19.
The maximum time duration of flash remains at that time deter-
mined by the discharge of the main storage capacitor 23 through
the first and the second flash tubes 17 and 19.
More specifically, when the flash light is reflected
into the phototransistor 47 from the object being photographed,
the resistance of the phototransistor 47 decreases rapidly
following the incident flash of light. Since the decay time of
the conductivity of photocell 47 is low relative to the flash
interval, the photocell 47 in and of itself effect_vely inte-
grates the incident light, converting that incident light intoa voltage
-- 10 --
~57~
.
signal of increasing magnitude appearing at the protecting
resistor 53, thence to the zener diode 49. When the signal at
zener diode 49 has reached a predetermined and fixed breakdown
voltage, the zener diode 49 becomes suddenly conductive and a
voltage is developed across the resistor 50 producing a sharp
pulse of energy to the gate electrode of the thyristor 45.
The sharp pulse applied to the gate electrode of the thyristor
45 causes that thyristor 45 to become suddenly conductive,
effectively short-circuiting the capacitor 48. This, in turn,
causes the capacitor 48 to discharge, thereby applying a sharp
pulse of energy to the input winding 42a of the quench trans-
former 42. The transformer 42 transmits the triggering pulse
from the output winding 42b thereof to the triggering electrode
38c of the quench tube 38, That triggering pulse causes the
quench tube 38 to become instantaneously conductive.
When the quench tube 38 becomes conductive, electric
charge of the commutation capacitor 40 also discharges through
the quench tube 38 and the commutation resistor 41, and thereby
the voltage is induced between both terminals of the commuta-
tion resistor 41 so as to be positive polarity at the cathode
electrode side of the first thyristor 32, after a time interval
decided by a time constant of the capacitor 40 and the resistor
41. This induced voltage at the resistor 41 causes the first
thyristor 32 to turn off. When the first thyristor becomes
non-conductive, the first and the second flash tubes 17 and l9
are simultaneously and instantaneously extinguished, because
the main current conducting electrode 17b and l9b of each flash
tubes 17 and 19 are commonly connected to the anode electrode
of the first thyristor 32.
In this case, since the quench tube 38 is the much
lower
, ......... _ . _
78
impedance, when conductive, than do the first flash tube 17
and the second flash tube 19, almost all of the stored energy
in main storage capacitor 23 is discharged through the current
limiting resistor 39 and the quench tube 38, causing the first
flash tube 17 and the second flash tube 19 to be extinguished
at such time as sufficient light has been reflected onto the
photocell 47 to effect the initiation of the quenching.
Fig. 3 shows an example of bounce photographing in a
room or photo-stu~io, by using the electric flash apparatus in
accordance with the present invention. As is best shown in
Fig~ 3, the flash housing 10 is mounted on a camera 54. The
first flashing member 16 of the first casing 11 is directed
toward an object to be photographed such as, for example, a
man 55. The second casing 12 is set with a suitable angle with
respect to the first casing 11, and the second flashing member
18 is directed toward a ceiling 56 with a desired angle with
respect to a surface of the ceiling 56, in order to apply the
reflected flash light to the object to be photographed. That
is to say, a flash light 58 from the first flashing member 16
is directed toward the man 55, and, on the other, a flash light
59 from the second flashing member 18 i9 directed toward the
surface of the ceiling 56. The flash light 59 reflects at the
surface of the ceiling 56 and forms the bounce light. One
reflected light 59a of the flash light 59 incidents on the man
55, and other reflected light 59b of the flash light 59 incident
on a background such as, for example, a wall 57 of the room.
The one reflected flash light 59a is superimposed with the
flash light 58 from the first fla3hing member 16 and, on the
other hand, the reflected light 59b gets rid of the shadow in
the background of the man 55.
, . . ~
~s~
As dlscussed in the ~asegoing, quantity oi the fla~h
light 59 is set 80 as to be greater than that oi the ilash `
light 58 produced irom the iirst flash tube 17 by connecting
the current-limitting resistor 37 thereto (see Fig. 1), as
is best shown in ~'ig. 4. Fig. 4 shows characteri~tics of
ilash light quantity ~ on the order of Beam Candle Per ~econd
(BCP~) with re~pect to Time T on the order oi Milliseco~d(l~S).
In Fig. 4, a curve 60 denote3 a ilash light characteristic oi
the first light tube 17, a curve 61 designates a ilash light
characteristic of the second ilash light tube 19 and a curve
62 illustrates the resultant quantities which is the 8um 0
the ~lash lights oi the iirst tube 17 and the second flash
tube 19. A~ is apparent from the curve 62 in ~ig. 4, a total
amount oi the flash light produced irom the flash apparat~s
in accordsnce with the present invention becomes greater thsn
that oi the conventional ilash apparatus which has only one
ilashlng member.
Accordingly, the photographing mode shown in Flg. 3,
brightness in the ob~ect to be photographed æuch as the man
55 increases and i8 made uniiorm. The ilash duration~ oi the
iirst ila~h tube 17 and the second ila~h tube 19 is determined
to the time interval 21 aB i8 shown ln Fig. 5. The tlme in-
terval '~1 i8 presel~cted in synchronlsm with the shutter
operation of the camera 54. The ilash duratlon~ oi the tube~
17 and 19 are synchronised and set at the time point Tl, and
each oi the tubes 17 and 19 are simultaneously extingui~hed
at the time '1`1 a8 is shown in Flg. 5. Accordingly, the un-
neces~ary ilashing o~ the tube~ 17 and 19 sre avoided and,
thereiore, the ~lashing periormance is enhanced, and thereby
the rated capacity oi the main storage capacitor 23 is made
~i~573~7~
small, although the apparatus is equipped with the first
flash tube 17 and the second flash tube 19. Furthermore, as
as the total quantity of the flash light is summed by the
light from first flashing member 16 and the second flashing
member, the total quantity of light incident on the photo-
graphic object and, as a result, the catch light is duly
obtained in the photographic object. Additionally, the
direct light to be directed toward the object to be photo-
graphed from the first flashing member 16 includes a direct
light which is directly directed to the object from the
flash tube and a direct light which is directed toward the
object from the flash tube by way of a reflecting member
such as a reflecting mirror. Furthermore, the bounced light
includes an indirect light which is directed toward the
ceiling from the flash tube and which is reflected from the
ceiling, and an indirect light which is generated from the
flash tube and thereafter is reflected from a reflecting
member positioned in the vicinity of the flash tube.
The electric flash apparatus described herein-
above and illustrated by the Figures has the advantage ofbeing very certain in operation and of enabling numerous
discharges of flash tubes to be effected without replacing
the various elements, since the triggering circuit member C
is constructed by only one trigger transformer 28 and only
one triggering capacitor 27,
The electric flash apparatus described hereinabove
has, moreover, advantage that the circuit construction is
- simplified and smallized, since the switching circuit D is
commonly and effectively used for a plurality of flash tubes
of the flash tube circuit E.
- 14 -
`l ~ 57~
As is apparent from the hereinabove description,
according to the present invention, the following advantages
are obtained.
An advantage over the prior art flash apparatus
is that the invention provides a new electric flash apparatus
which can perform the bounce photographing by means of setting
an angle between a first casing and a second casing to the
desired value since the first casing and the second casing
are rotatably connected to each.
Another advantage of the invention is that both of
a first flashing member and a second flashing member can also
be used as a direct-light source by directing the both of
- 14a -
~7~78
them toward the object to be photographed and, as a result,
the qu;~ntity of an incident light to the object increases to
that extent.
A further advantage of the invention is that an electric
~lash apparatus is convenient to take a photograph, particular-
ly to taking a picture by employing a bounce light because a
~lash housing is rotably constructed by a first casing and a
second casing, each o~ the casing has a ~lashing member.
In view of the above, it will be seen that the several
objects of the invention are achieved and other advantageous
results attained.
While a pre~ered embodiment of the invention has been
shown and described, it will be apparent to those skilled in
the art that modifications can be made without departing
from the principle and spirit o~ the invention, the scope oY
which is de~ined in the appended claims. Accordingly, the
foregoing embodiment is to be considered illustrative, rather
than restricting of the invention and those modiYications
which come within the meaning and range o~ equivalency oY
the claims are to be included herein.
