U.S. patent number 3,639,770 [Application Number 04/761,685] was granted by the patent office on 1972-02-01 for optoelectronic semiconductor device.
This patent grant is currently assigned to Telefunken Patenverwertungsgesellschaft mbH. Invention is credited to Walter Zizelmann.
United States Patent |
3,639,770 |
Zizelmann |
February 1, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
OPTOELECTRONIC SEMICONDUCTOR DEVICE
Abstract
An optoelectronic or photosensitive semiconductor device in
which a light-emitting element and a light-responsive element are
arranged in a common casing, the degree of photocoupling between
the two elements being dependent entirely on conditions exterior of
the casing. In one embodiment, the two elements are embedded in a
light-permeable mass, the boundary surface of which, together with
a medium surrounding the mass, forms a surface whose reflection
characteristic is dependent on the indices of refraction of the
mass and of the medium, the elements themselves being so arranged
that when the index of refraction of the medium is such that the
boundary reflects the light coming from the light-emitting element,
the reflected light is picked up by the light-responsive element,
with the amount of light being picked up being dependent on, and
thus an indication of, the medium surrounding the mass. In another
embodiment, light emitted by the light-emitting element is free to
exit the mass and, if reflected by an object outside the mass, is
picked up by the light-responsive element.
Inventors: |
Zizelmann; Walter (Alpirsbach,
DT) |
Assignee: |
Telefunken
Patenverwertungsgesellschaft mbH (Ulm/Donau,
DT)
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Family
ID: |
7558830 |
Appl.
No.: |
04/761,685 |
Filed: |
September 23, 1968 |
Foreign Application Priority Data
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Sep 27, 1967 [DT] |
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T 34891 |
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Current U.S.
Class: |
250/574; 250/239;
250/577; 257/724; 340/619; 356/136; 73/293; 250/551; 257/82;
257/725; 340/555; 356/133 |
Current CPC
Class: |
G01F
23/2925 (20130101); G01N 21/43 (20130101) |
Current International
Class: |
G01N
21/41 (20060101); G01N 21/43 (20060101); G01F
23/284 (20060101); G01F 23/292 (20060101); G01n
021/26 (); G01n 021/46 (); G02b 021/00 (); H01j
039/02 () |
Field of
Search: |
;250/239,218
;356/135,133 ;340/234,237,244 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Freeman-IBM Technical Disclosure Bulletin, Vol. 5, No. 1, June
1962.
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Primary Examiner: Lake; Roy
Assistant Examiner: Lafranchi; V.
Claims
I claim:
1. An optoelectronic semiconductor device comprising, in
combination:
a. a radiation-permeable mass selected from the group consisting of
resin, glass, and a mixture of resin and glass, and constructed in
the form of a closed casing having a hemispherical or conical
configuration having an index of refraction and defining an outer
boundary surface.
b. a radiation-emitting gallium-arsenide luminescence-type diode
embedded in said mass and arranged to emit a beam of radiation at
an angle of incidence with respect to said boundary surface which
is less than the critical angle at said boundary surface when said
boundary surface is surrounded by a liquid medium to permit
substantially all of the radiated beam to freely exit from said
mass, and greater than the critical angle at said boundary surface
when said boundary surface is surrounded by a gaseous medium to
reflect substantially all of the radiated beam as a function of the
index of refraction of said gaseous medium;
c. a radiation-responsive semiconductor element embedded in said
mass and arranged in the path of radiation reflected from said
boundary surface to receive same; and
d. a socket connected to said mass which mass enlarges toward said
socket, and leads extending through said socket and connected to
the radiation emitting diode and the radiation-responsive element,
the radiation emitting diode being arranged on said socket and said
radiation responsive semiconductor element being spaced from said
socket and supported on one end of one of said leads, which lead
extends beyond said socket and into said mass.
2. An optoelectronic semiconductor device comprising, in
combination:
a. a radiation-permeable mass forming a closed hemispherical
casing;
b. a radiation-emitting gallium-arsenide luminescence diode
embedded in said mass near the center of said hemispherical casing
and arranged to emit radiation which exits from said mass without
being reflected;
c. a radiation-responsive silicon photodiode embedded in said mass
near the center of said hemispherical casing and adjacent the
radiation-emitting diode and arranged to receive radiation emitted
by said radiation-emitting diode and reflected by striking an
opaque object to be detected outside of said mass; and
d. a socket connected to said mass and having a bottom surface on
which said diodes are mounted, which mass enlarges toward said
socket, and leads extending through said socket and connected to
said diodes.
3. An optoelectronic semiconductor device comprising, in
combination;
a. a radiation-permeable mass forming a closed casing;
b. a radiation-emitting element embedded in said mass;
c. a radiation-responsive element embedded in said mass for
receiving radiation emitted by said radiation-emitting element and
reflected back into the mass; and
d. a socket connected to said mass and having a bottom surface on
which at least said radiation-emitting element is mounted, which
mass enlarges toward said socket, and leads extending through said
socket and connected to said elements.
4. A device as defined in claim 3, wherein said
radiation-responsive element is mounted on said bottom surface.
5. A device as defined in claim 3 wherein said mass is
hemispherical or conical.
6. A device as defined in claim 3 wherein said radiation-emitting
element is a gallium-arsenide luminescence-type diode.
7. A device as defined in claim 3 wherein said radiation-responsive
element is a silicon photodiode, a phototransistor, or a
photoresistor.
Description
BACKGROUND OF THE INVENTION
There exist various types of photosensitive devices by means of
which the absence or presence of various types of objects can be
determined. Such devices include a light-emitting element and a
light-responsive element, which must be strategically placed so
that the light going from the former to the latter will follow a
path which cuts across the space occupied by the object the
presence or absence of which is to be determined. This creates a
number of difficulties, not only insofar as the placement of the
elements is concerned, but also insofar as manufacturing and
installation costs are concerned.
It is, therefore, the object of the present invention to provide a
way in which to overcome the above drawbacks.
BRIEF DESCRIPTION OF THE INVENTION
With the above object in view, the present invention relates to an
optoelectronic semiconductor device having a light-emitting element
as well as a light-responsive element, the two elements being
arranged in a common light-permeable casing in such a way as to
make possible the determination of a characteristic of the medium
surrounding the casing, or of an object next to the casing, from
the degree of the optoelectronic coupling between the two
elements.
Thanks to the fact that, in accordance with the present invention
and in contradistinction to the known prior art, the light source
as well as the light receiver or pickup are accommodated in a
common housing, the manufacture and construction of indicator
apparatus incorporating light-responsive elements is significantly
simplified and the cost and installation of this type equipment,
which is generally used for recording and counting, is reduced.
More particularly, the present invention resides in a
photosensitive device in which the light-emitting and
light-responsive elements are embedded in a common light-permeable
casing, the elements being so arranged that the amount of light
picked up by the light-responsive element is dependent on
conditions which are entirely exterior of the casing.
According to one embodiment of the present invention, the elements
are embedded in a mass, the boundary surface between the mass and
the medium surrounding the mass forming a surface whose reflection
characteristic is dependent on the indices of refraction of the
mass and of the medium, the index of refraction of the mass being
so selected and the elements being so arranged that when the medium
outside the mass is gaseous, light emitted by the light-emitting
element is reflected by the boundary surface so as to strike the
light-sensitive element, whereas, when the medium is a liquid,
virtually none of the light is reflected. In practice, the amount
of light which is reflected will depend on the index of refraction
of the liquid.
According to another embodiment, the light emitted by the
light-emitting element exits from the light-permeable mass but is
picked up if reflected by an opaque object outside of the mass.
Thanks to the above arrangement, the type of medium surrounding the
casing, or the presence of an object outside of the casing, can be
determined and the device can be used, for example, to respond to
and control a liquid level in that the output obtained from the
light-responsive element will depend on whether or not, and how
much, light strikes this element.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are sectional views of one embodiment of a device
according to the present invention which is suitable for indicating
and controlling liquid levels, the two figures showing the
operation of the device when the same is surrounded by two
different media.
FIGS. 3 and 4 are sectional views of another embodiment of a device
according to the present invention, the two figures showing the
operation of the device when used for counting and recording
passing objects.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings and first to FIG. 1 thereof, the same
shows a semiconductor device comprising a socket 1, through which
extend three electrode leads 2, 3, 4, which are electrically
insulated from the socket and from each other, there being a fourth
electrode lead 5 which is electrically conductively connected to
the metallic bottom of the socket 1. The lead 3 is shown as
extending upwardly beyond the bottom of the socket, there being a
light-responsive element 6 arranged at the top of lead 3, one
electrode of this element 6 being electrically connected with the
top of the lead 3. This element 6 is, for example, a silicon
photodiode or photoresistor, whose other electrode is connected, by
way of a thin connecting wire 7, with one of the other lead, such
as the lead 2 as shown in FIG. 1. If desired, the connecting wire 7
can be dispensed with by extending the lead 2 upwardly and by
bending the ends of leads 2 and 3 in such a way that the
light-responsive element 6 is between the ends of the two leads and
is thus electrically connected to both. In any event, the
light-responsive element is located generally above the center of
the socket.
A light-emitting element 9, for example, a gallium-arsenide
luminescence-type diode, is arranged in the region of the edge of
the bottom surface 8 of the socket and has one of its electrodes
electrically connected with another of the leads, e.g., the lead 5
as shown, the other electrode of the element 9 being connected to
the fourth lead 4 via a further connecting wire 7a.
The socket 1 as well as the electrode connections and the
semiconductor elements 6 and 9 are embedded in a light-permeable
mass 10, such as glass, synthetic resin, or a mixture of the two.
This light-permeable mass 10 thus forms a closed casing and, as
shown in FIG. 1, has a conical configuration which enlarges in the
direction from the top, as viewed in FIG. 1, toward the socket.
If, now, the element 9 is excited by means of an electric current
flowing therethrough, the element will emit a beam of light 11,
which will strike the boundary surface 13 between the
light-permeable mass 10 and the surrounding medium 12 at a very
large angle of incidence (this being the angle between the light
beam and the perpendicular to the boundary surface at the point of
incidence), namely, an angle of incidence which is but slightly
less than 90.degree.. If the medium 12 surrounding the casing 10 is
a gaseous medium, the angle of incidence will be greater than the
critical angle and the entire light beam 13 will be reflected at
the boundary surface 13 and will impinge on the light-sensitive
layer of the element 6, the precise position of which is such as to
be in the path of light emitted by element 9 and reflected by the
boundary surface 13. Thus, the light-sensitive characteristic of
the element 6 will be markedly affected by the large amount of
light which strikes the element 6 when the device is surrounded by
a gaseous medium.
If, however, the device is immersed in a liquid as shown in FIG. 2,
the angle of incidence will be less than the critical angle and the
boundary surface 13 between the casing 10 and the medium 12 will
not reflect the light beam 11; instead, the same will freely exit
the mass and pass through the boundary surface 13 and into the
liquid medium. The element 6 is thus not subjected to illumination
emanating from the element 9.
It will thus be seen that whether or not the arrangement is in a
liquid can be determined by measuring the characteristic of the
element 6, since this characteristic will be markedly different
depending on whether the casing 10 is surrounded by a gaseous or a
liquid medium. This can be done electrically, via the leads 2 and
3, in a manner well known in the art. The electrical output of this
measurement can then be used to give an indication of the height of
a liquid level, or for controlling switching systems, pumps,
motors, or the like, for example, for the purpose of controlling a
liquid level under various conditions, such as in washing machines,
in fountains, or in storage tanks containing water, gasoline, oil,
or any other liquid.
In the preceding discussion, it was assumed that the liquid is a
clear liquid. If, however, the liquid is not clear but a
light-dispersing such as milk, some of the light emanating from the
element 9 will strike the element 6. The amount of this light will
depend on the opaqueness or cloudiness of the liquid, so that the
characteristic of the element 6 can be used as a measure of the
light-dispersing characteristic of the liquid. Thus, the purity or
cloudiness of the liquid surrounding the casing 10 can be
determined, as this will affect the light sensitive characteristic
of element 6.
The following is an illustrative and not limitative example of the
embodiment described above. The light-responsive element 6 is a
silicon diode, and the element 9 is a GaAs luminescence diode. The
mass 10 is made of epoxy resin and has an index of refraction of
about 1.5. In normal operation the excitation current applied to
element 9 is 100 m.A. DC. When the arrangement is surrounded by air
and the maximum light from element 9 is reflected by the boundary
surface 13 to impinge on element 6, the output current is 9 .mu.A.;
when the arrangement is submersed in clear water, the output
current of element 6 is 1 .mu.A. With the arrangement being
submersed in milk, there was obtained an output from elements 6 of
13 .mu.A.; in water with a milk content of 10 percent, the output
was 2 .mu.A.; in water with a milk content of 50 percent, the
output was 7 .mu.A.; in oil and in gasoline, the output was the
same as in water (about 1 .mu.A.).
FIG. 3 shows another embodiment of a device according to the
present invention wherein both the light-emitting and the
light-responsive elements 9' and 6', which may again be constituted
by a gallium-arsenide luminescence diode and a silicon photodiode,
respectively, each having one of their electrodes in direct
electrical contact with the bottom surface 8' of the socket 1. The
two elements 6', 9', are arranged generally in the center of the
bottom surface, the same normally being circular. In this
embodiment, the lead 5' is electrically connected with the socket
while the other two leads, namely 2' and 3', are insulated from the
socket and contact the other electrodes of the two semiconductor
elements, respectively. The light-permeable mass 10', in which the
other components are embedded or which, if made of resin, may be
molded to the other components, is shown as arching upwardly in a
substantially hemispherical configuration.
If, now, as shown in FIG. 3, the element 9' is excited and puts out
a light beam 11', the same strikes the spherical boundary surface
14 between the mass 10' and the surrounding medium 12-- normally
air-- at practically a right angle, so that if there is nothing
near the device which would reflect the light, the element 6' will
receive virtually no light. If, however, an opaque object 15 is
moved past the arrangement in the direction of the arrow 15a, as
shown in FIG. 4, a portion 16 of the light beam 11' is reflected
and will strike the element 6', which responds by changing its
characteristic as the result of the impinging light. In this way,
the passage of an article can be noted, the output signal of the
device being applied to any suitable recording apparatus or
counter, or otherwise be processed to utilize the information.
In both the above-described device as well as in that described in
connection with FIGS. 1 and 2, the light emitting element can be
energized to emit alternating light, so as to make the device as
independent as possible from ambient light conditions.
The following is an illustrative and not limitative example of the
embodiment described in connection with FIGS. 3 and 4, the same
incorporating similar light-emitting and light-sensitive elements
and a similar light-permeable mass as that which described in
conjunction with the specific example of the embodiment of FIGS. 1
and 2. When no light from element 9' was reflected on element 6',
the output of the latter was 100 .mu.A.; when an opaque plate was
passed within a distance from the element of approximately 0.5 mm.,
sufficient light was reflected onto the element 6' to obtain from
it an output of 300 .mu.A.
It will be understood that the above description of the present
invention is susceptible to various modifications, changes and
adaptations. For example, the precise spatial location of the
light-emitting and light-responsive elements can be varied, as can
the shape and composition of the light-permeable mass, and the
number of leads, the latter depending on whether the elements will
have a common lead and/or the number of electrodes of the elements.
For instance, if the light-sensitive element is a phototransistor
instead of a diode, an additional lead will be provided.
The terms "light-emitting," "light-responsive" and
"light-permeable" as used throughout the instant specification and
claims, are intended to comprehend not only visible light but also
invisible light and other radiation having characteristics which
are technologically and scientifically equivalent to light
radiations.
* * * * *