Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to an infrared irradiation device for
medical purposes utilizing the principle of genera-ting heat
emitted by a surface by applying electric potential to remote
sides of a variably conductive heating film preferably produced
by applying a synthetic resin dispersion blended with carbon
bl~ck to a substrate and subsequently insulating the exposed
~aak side of the heating film by polyurethane hard ~oam.
Irradiation devices for medical purposes working in the infrared
range have become known in many forms. Normally infrared lamps
are used in stationary or movably arranged infrared irradiation
devices. Such irradiation devices are best known in the form of
a conventional lamp with lamp stand and rigidly or movably
mounted radiation reflector in which the infrared bulb is
installed. `'
The manufacture and operation of these known irradiation devices
are relatively expensive, particularly since the infrared bulbs
have a limited service life. Moreover, it is very difficult to
vary and limit the radiation emission both regarding intensi-ty
and regarding the irradiated area, unless the irradiati.on is
carried out with irradiation devices especially designed for
treating specific parts of the body, e.g. devices developed
especially for irradiation of the eyes or of the ears. Even so
the handling of these devices is problematic. In particular ?
the patient must assume and maintain a qulte specific position
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~~ relative to the irradition device ove~ a longer period of
time which is normally required for treat~ent with infrared
radiation, in order that firstly the radiation intensity and
also the irradiated area itself always remain the same. There
are substantially no suitable devices available for treating
~he whole body, e.g. in intensive care hospital wards or in
ambulances after accidents or the like.
The initially mentioned principle for generatillg heat
utilizing an electrically conductive heating film of synthetic
resin dispersion and carbon black has been described in many
publications. However, in these instances ~ainly the problem
of heating rooms by means of flat heating elements is concerned
which may be used also for other pruposes, e.g. as electric
heating pads. Insofar such flat heating elements have been
proposed already for the medical fleld, but e~clusively for
the purpose of direct transfer of heat~
In one particular aspect the present inventlon provides
an infrared irradiation device for medical purposes utlllzlng
the principle of generatlng heat emltted by a surface by
applying electric potcntial to remote sides of a variably
conductive heating film produced by applying a synthetic
resin dispersion blended ~ith carbon black onto a substrate,
comprising in an upper part (la) of a housing (1) provided
with a handle (3) there is sequentially arranged a substrate
(4) of a material which, when giving off heat, emits a high
proportion of radiant heat, a heating film (5) with ~erminal
electrodes (9) connected to electric supply means (10), and
a highly effective heat insulating layer (6) 9 and adjacent
substrate ~4~, a lower part (lb) which serves as a spacing
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Such an irradiation device opens up new possibili~ies of
irradiation in the medical field, and the patient is thereby
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enabled to treat himself in his home without any difficulties
and problems, particularly also because the irradiation
devices o~ the invention can be manufactured at relatively
low cost.
~ he irradiation devices of the invention offer the
special advantage that they can be readily adapted to and
placed over the part of the body to be irradiated and
possibly fixed to the body itself, as will be explained
further below. This permit~ very uniform irradiation which
is precisely confined to the body region that is actually to
be treated. Since the irradiation device and the irradiated
body region form a substantially closed system which is
ef~ectively insulated by the heat insulating layer on the
back side of the heating film and at best provided with
ventilating openings, as will be explained further below,
nearly all the generated heat is converted to radiation in
the infrared range, and nearly all of said radiation is
supplied to the trea~ed body portion. This not only offers
the advantage that body portions outside the region to be
ereated are not automatically irradiated, too; ~he concentration
of the irradiation treatment also permits to work with
substsntially less electric power than that required by the
hitherto conventional
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irradiation devices using infrared bulbs. Thus, the irradia-tion
devices of -the invention can be operated withou-t disadvantage,
and with the advantage of avoiding accidents, at a lower voltage
of 24 voltsg for instance, which is delivered either by the mains
through a transformer or by a rechargeable battery or the like.
It will he shown in more detail further below -that the invention
permits in a simple way the individual design of irradiation
devices for treating the ear, the eye, the extremities, espe-
cially feet, knees or the like and the body as a whole, part-
icularly also the kidneys, the liver, the stomach, and parts of
the body af~licted by rheumatism. Also the use of the devices in
intensive care , ambulances and after accidents is readily
possible.
When a special irradiation is required, the substrate and, accord-
ingly, also the overlying layers are arched upwardly.
Particularly in cases where -the design of the irradiation device
requires a relative low spacing means, e.g. in cases where -the
irradiation device is designed in the manner of a bandage that
may be applied over the body portion to be treated, a detachable
grid will suitably be provided in the lower portion of the hous-
ing as protection against contact. A further embodimen-t of the
irradiation device of the invention is particularly important
in which the lower rim of the housing is provided with a cushion
of soft elastic material, e.g. foamed rubber with non porous
skin. This cushion has several functions. It i.nsulates the body
against the spacing means in case the latter is made from therm-
ally conductive material and may perhaps be heated up, too,
during the treatment. It acts as a seal of the irradiation system
and avoids undesirable escape of heat to the environment. With
an accordingly selected embodiment it primarily permits adaption
of the lower rim of the housing, namely of the spacing means, to
irregular body contours on which the spacing means is placed.
Finally, the cushion avoids any unpleasant pressure of edges as
the spacing means is placed on parts of the body.
The lower rim of the housing or the cushion itself should have
perforations or recesses allowing ventilation of the treated
body region.
A versatile infrared irradiation device according to the invent-
ion is obtained when the upper part and the lower part of -the
housing form two separate units~ and a desired and suitable
lower part may be selected from a set of differently designed
and equipped lower parts and exchangeably attached to the upper
part carrying the irradiation system. In this way a universal
upper part carrying the irradiation system can be at-tached to
differently designed lower parts so that the device will be
suited for treating various parts of the body, depending on -the
height of the spacing means and depending on the configuration
of the lo~-er rim.
~ccording to still another embodiment it is contemplated to apply
at least one housing with irradiation sys-tem especially for
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irradiation of the ear to a device resembling the strap of ear
phones. The device may be such that -the patient is able to hear
also during the period of treatment.
For a number of other applications it is advantageous to design
the housing with irradiation system in the form of an elongate
bandage whieh may be secured to the body and which is flexible
w.ithin certain limits at least in longitudinal direction for
irradiation of body portions in the region of the stomach, liver,
kidneys etc. The flexible embodiment requires the use of an
accordingly flexible metal sheet or the like as substrate.
In a further favorable embodiment it is contemplated to design
the housing with radiation system as an elongate trough with
oI~en bottom for heating the whole body in case ~f accidents, in
intensive care wards, etc. For such applications the irradiation
device may be divided into several sections in -transverse direct-
ion, if occasion arises.
~lereafter the invention will be explained in more detail by
means of examples with reference to the drawings in which
Fi~. 1 shows a lateral view of an infrared irradiation device,
partially in section;
Fi~. 2 is a lateral view of an infrared irradiation device with
exchangeable lower part;
Fig. 3 is a schematic illustration of the embodiment of an in-
frared irradiation device for convex body portions such
as elbow, knee ete.;
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Figs, ~ to 6 show various further possibilities
of designing infrared irradiation devices that ar~ suited
for special applications;
Fig, 7, which appears on the sheet o drawings
bearing Fig, 3, is a section through an infrared
irradiation device having a high elongate spacing means,
The irradiation device shown in Fig, 1 has a
plastic housin~ 1 which is subdivided into an uppèr part la
and a lower part-lb designed as spacing means with a
cushioned lower rim 2 which consists~ for instance, of a
soft elastic foamed rubber pro-file with non-porous outer
skin (or bettèr cleaning) and may have on its underside
openings 7 for ventilation of irradiated body portions~
The upper part la which is provided with a handle
3 for convenient and safe holding accommodates the
irradiation system proper. Seen from bottom to top~ this
system consists of a substrate ~ with a heating film 5 on
its back side with electrodes in spaced opposite relationship
which are connected to a flexible cord 10 with plug 13
extending through the housing 1 and possibly with a
transformer 11 to convert the power mains voltage to a lower
voita~e and switch 12, a thick polyurethane hard oam layer
directly overlying the heating film 5 which suitably fills
all of the upper part la.
~'he lower part lb may have holes 8 to provide
additional possibilities for ventilation, Furthermore~ a
grid 15 of poorly heat-conductive material may be
detachably installed in spaced
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relation from the substrate 4 in the lower part lb, as additional
protection against contact.
An infrared irradiation device designed in this manner is suited,
for instance, for infrared irradiation of the ear, of th~ eye,
or of other body portions, depending on the selected size and
output of the device. The patient himself or an operator places
the device on the body region to be irradia-ted and safely holds
it in the selected position by means of the handle 3. A few
seconds after the power has been turned on by means of switch 12
the heat commences to radiate from the substrate 4 as soon as the
heating film 5 on its back side has been heated by -the supplied
power. In any event, a control should be provided at the device
itself or in the electric cord 10 by means of which the desired
radiation intensity may be selected by variation of the applied
voltage.
The sandwiched radiation system may be manufac-tured by a tech-
nique known on principle which may follow -the below indicated
procedure, for instance:
First the substrate 4 is produced which ~ owing to the -type of
material selected for the substrate 4 or owing ~o a suitable
coating - gives off an ex-traordinarily high amount of radiation
on its front side, i.e. the portion of the heat emanated by
radiation as the substrate is heated up is as high as possible.
Also an enamel~coated substrate 4 may be employed, since enamel
forms a hygienic, antibacterialj and toxicologically
unobjectionable coating. On the back side of the substrate ~
there is provided an electrically insulating film, if necessary.
The substrate may consist, for instance~of epoxide-coatecl steel
sheet. Directly on the back side of the substrate 4 or on the
electrically insulating ~ilm the heating film 5 is applied which
consists of a synthetic resin dispersion blended with carbon
n black, e.g. the BAS~ product Acronal, and carbon black. The two
electrodes 9 provided at opposi-te ends of the substrate 4 are
embedded in the heating film S. In a mold suitably corresponding
to the upper part la the polyurethane hard foam layer 6 is
formed by direct application on the heating film 5. The thus
formed radiation unit is inserted into the plastic housing 1
which, in this embodiment, is suitably made of one piece, where-
upon the electric cord 10 is connected to the electrodes 9.
The heating film 5 is adjusted such that a tempera-ture that
should not exceed 50 to 60C,~with 70C. as the uppermost limit,
is reached at the front face of the substrate 4. Yet, in some
applicati.ons it may be necessary to admit also tempera-tures up
to 90C. which requires an accordingly safe design of ~he device
in order to exclude any burning hazard. In this case the extra-
ordinarily effective polyurethane hard foam layer 6 or its s-tab-
ility sets the limit for the uppermost temperature level.
.
The heating film 5 is preferably connected to low voltage of
24 volts, at best SO volts, and the voltage should be variable
in order to permit variation of the radiation intensity.
In the example shown in Fig. 2 the radiation unit is likewise
accommodated in the upper part la, while the lower part lb is
one component of a set of exchangeable lower parts which are
designed and equipped for various applications. In the present
example the lower par~ lb is suited for accommodating an insert
18 whi~h may be opened and filled with active substances such as
plant extracts or the like, but which is constructed such that
the radiation from the radiation unit may largely traverse the
insert 18. To this end the insert 18 suitably has the form oE a
grid~ or it occupies only part of the free cross section of the
lower part lb. The lower part lb can be screwed into the upper
portion, for instance, by means of a threaded portion 19. It may
also be secured thereto by clamping.
Fig. 3 shows an embodiment of an infrared irradiation device
which is suited, for instance, for treating the knee. To this
end the irradiation unit has a corresponding arch. Such an arch
or dome is preferred also when a sort of radiation focussing on
a relatively small body region is to be achieved.
Figs. 4, 5 and 6 illustrate further embodiments of the infrared
irradiation device of the invention.
In the example of an infrared irradiation device shown in Fig. 7
the housing of the device has been designed substantially
entirely as`upper part la with the already described radiation
system in the form of an elongate hollow structure closed at its
upper end. In this way the inner heat supplying surface of the
radiation device may be substantially enlarged, The polyure-
thane hard foam insulation has a non-slipping surface so that
the provision of special handles or the like may possibly be
foregone. The cushioned lower rim 2 has recesses 7 in its con-
stricted region 20 with variable ~pening widths. When more
hea~ is desired, a certain pressure on the cushioned lower rim
will at least partially close the openings 7. Vice versa~ the
pressure can be entirely or partially relieved when warm air
is to escape from the interior la and the radiation is to be
less intensive.
It is assumed that the mode of effect of the infrared irrad-
iation devices is due to the following circumstances:
The penetrability of animal and human tissue by electromagnetic
radiation is dependent less on the type of skin (apar-t from
extremely highly pigmented skin) than on the wavelength of
the applied radiation. Within the range from visible light
~violet ~ 380 nm wavelength to red - 750 nm wavelength) up to
long infrared waves (black-body tèmperature radiator of 40C.
- 9259 nm wavelength of the radiation maximum) -the pene-trab
ility increases with the wavelength. 1 nm 1 x 10 9 m. To
attain a high degree of penetration one must consequently use
long-wave infrared "light".
In turn, the radiation maximum of the wavelength depends on
the temperature of the radiator in the known infrared
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irradiation devices and in the devices of the invention, in
accordance with Wien's displacement law, since said infrared
irradiation devices may be regarded as black-body radiators
for the emitted radiation.
When the surface temperature for th~ infrared irradiation de-
vices of the invention is 50C., for instance, the radiation
maximum of the wavelength is 8972 nm. On the other hand, when
a known infrared irradiation lamp is employed, two different
radiation maxima of wavelength occur which are associated to
two different ranges of emission 9 namely to the red-hot heating
filament having a temperature of about 1700C. and to -the glass
envelope of the bulb having a temperature of about 200C. The
1700C. radlation has a wavelength maximum of 1468 nm and
amounts to about 25% of the total radiation with longer and
shorter wavelengths - according to Planck's radiation law.
The corresponding data for the 200C. radiation are 6126 nm
and 75~.
The depth of penetration of the radiation is about proportion-
al to the square root of the radiation maximum of the wavelength.
Therefrom it follows that the 50C. radiation of the infrared
irradiation device penetrates into the body tissue 2.472 times
deeper than the 1700C. radiation and 1.21 time.s deeper than
the 200C. infrared irradiation lamp. This implies tha-t with
equal depth of penetration with the types of irradiation under
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comparison the infrared irradiation lamp additionally emits
heat mainly absorbed in the skin strata, which may be harmful
and even may cause burns, if -the deep penetra-tion is maximized.
In other words, with equal heating of -the surface the deep
penetration in the infrared irradiation device of the invent-
ion can be substantially intensified without any ha~ard of
burning the skin, which permits far more intensive irradiation
and thus a better -therapeutical effect.
It is another advantage of the invention that, on account of
the comparatively larger radiation surface, a lower radiation
output density per unit area is sufficient which results in
the relatively lower surface temperature of the radiant area,
in accordance with the Stefan-Boltzmann law. The known infra-
red irradiation lamps, on -the other hand, may cause burns in
case they are accidentally touched. This risk hardly exists
with the infrared irradiation devices oE the inventlon clue -to
the substantially lower surface temperature. ~t best a 1st
degree burn (skin reddening) but in no case a 2nd degree or
even 3rd degree burn may occur. The radiation of heat from a
large area according to the inven-tion offers the further ad-
van-tage that the radiation output density is applied with
utmost uniformity over the body surface being -trea-ted.
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