United States Patent [19]
`Schöberl
`
`[11]
`[45]
`
`4,143,394
`Mar. 6, 1979
`
`[54] SEMICONDUCTOR LUMINESCENCE
`DEVICE WITH HOUSING
`[75] Inventor: Werner Schöberl,
`Massenbachhausen, Fed. Rep. of
`Germany
`
`[73] Assignee:
`
`Licentia
`Patent-Verwaltungs-G.m.b.H.,
`Frankfurt am Main, Fed. Rep. of
`Germany
`[21] Appl. No.: 817,518
`[22] Filed:
`Jul. 20, 1977
`[30]
`Foreign Application Priority Data
`Jul. 30, 1976 [DE] Fed. Rep. of Germany ....... 2634264
`[51] Int. Cl.” ...................... H01L 23/28; H01L 33/00
`[52] U.S. Cl. ........................................ 357/72; 357/17;
`313/500; 313/512
`
`[58] Field of Search ............................. 357/17, 72, 30;
`313/500, 512
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`1/1971 Johnson ................................. 357/17
`3,555,335
`2/1972 Zizelmann ............................. 357/72
`3,639,770
`3,694,902 10/1972 Apgar et al. ........................... 357/17
`3,883,772
`5/1975 Wako et al. ............................ 357/17
`4,047,075
`9/1977 Schoberl ................................ 357/72
`Primary Examiner—Andrew J. James
`Attorney, Agent, or Firm—Spencer & Kaye
`[57]
`ABSTRACT
`A semiconductor luminescence component comprises a
`light emitting element in a light transmitting casing, the
`casing having internal surfaces for total internal reflec
`tion for light rays emitted laterally by the light emitting
`element.
`
`12 Claims, 3 Drawing Figures
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`VIZIO 1020
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`U.S. Patent
`U.S. Patent
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`Mar. 6, 1979
`Mar. 6, 1979
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`4,143,394
`4,143,394
`
`
`
`FIG.3
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`VIZIO 1020
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`VIZIO 1020
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`1
`SEMICONDUCTOR LUMINESCENCE DEVICE
`WITH HOUSING
`BACKGROUND OF THE INVENTION
`The invention relates to a semiconductor lumines
`cence component with a light-transmissive casing. This
`type of component, which is formed usually by light
`emitting diodes, is already known. The light-emitting
`diode is cast in a plastic body which serves as a photo
`10
`conductor and has substantially the same cross-section
`over its entire length. The end face of this casing body
`remote from the semiconductor component serves as a
`light outlet surface, which is to be illuminated as well
`and as evenly as possible.
`SUMMARY OF THE INVENTION
`It is an object of the invention to provide a semicon
`ductor luminescence component in which, as far as
`20
`possible, all of the light emitted by the semiconductor
`component is visible evenly distributed over a relatively
`large light outlet surface.
`According to the invention, there is provided a semi
`conductor luminescence component comprising a semi
`25
`conductor light emitting element, a light transmitting
`casing for said semiconductor component defining sur
`faces providing total internal reflection for light rays
`from said semiconductor element laterally thereof.
`Further according to the invention, there is provided
`30
`a semiconductor luminescence component having a
`light-transmissive casing characterized in that the cas
`ing wall runs, in its lower casing part, at such an angle
`to the light rays escaping laterally from the semicon
`ductor component and falling on the casing wall, that
`35
`the light falling there is reflected back into the casing in
`a direction towards the casing end serving as a light
`outlet surface.
`BRIEF DESCRIPTION OF THE DRAWINGS
`The invention will now be described in greater detail,
`by way of example, with reference to the drawings, in
`which:
`FIG. 1 is a perspective view of a semiconductor lumi
`nescence component in accordance with the invention;
`45
`FIG. 2 is a perspective view of a different form of
`component in accordance with the invention, and
`FIG. 3 is a perspective view of yet another form of
`component.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`In a preferred form of the invention in a semiconduc
`tor luminescence component with a light-transmissive
`casing, it is proposed that the lower casing part of the
`55
`casing wall runs at such an angle to the rays of light
`originating laterally of the semiconductor component
`and meeting on the casing wall, that the light meeting
`there is reflected back into the casing in a direction
`towards the end of the casing serving as a light outlet
`surface.
`In one embodiment of the casing the light rays ema
`nating laterally from the semiconductor body, in the
`manner described, no longer emanate from the casing,
`but are reflected back by means of total reflection in the
`65
`interior of the casing to the light outlet surface. This
`means that loss of light resulting from the escape of
`parts of the light at the side faces of the casing is either
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`4,143,394
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`completely or partially avoided and thus a large degree
`of efficiency of the light-emitting diode is ensured.
`The semiconductor casing may be constructed in
`different ways. As an example, the casing is plate
`shaped in its upper part and has a constantly rectangular
`cross-section. The casing narrows at its lower part, at
`least at two opposite side faces, by an angle which is
`selected so that the light rays meeting these faces are
`reflected back into the inside of the casing in a direction
`towards the light outlet surface.
`In a very narrow plastics casing, as is required for the
`purpose of forming illuminating lines, the two narrow
`sides of the casing wall will preferably run at an angle of
`approximately 70° to the surface, in the lower part of
`the casing, carrying the semiconductor component.
`In another embodiment the casing may be con
`structed so as to be square in its upper part in which the
`edges of the casing are substantially of equal length.
`With this casing shape, the lower part of the casing, on
`which the rays of light originating laterally of the semi
`conductor component fall, will preferably be tapered in
`pyramid shape.
`Furthermore, the casing may be cylindrical in its
`upper part with constant circular or eliptical cross-sec
`tion. In its lower part the casing is then tapered coni
`cally, whereby the angle and beginning of the tapering
`is selected at the casing sleeve surface such that the light
`rays originating laterally of the semiconductor compo
`nent, which would otherwise penetrate the casing wall
`and thus be lost, are reflected back into the inside of the
`casing. The angle of tapering is preferably 70° with
`respect to the plate or surface carrying the semiconduc
`tor component.
`The casing preferably comprises polycarbonate or
`epoxy resin and contains 1 to 5% powdered glass for
`the purpose of improving illumination. The light outlet
`surface is provided with a fine structure or is roughened
`in order to achieve even illumination. The remaining
`casing sleeve surfaces, particularly the sleeve surfaces,
`which serve for the purpose of reflecting light rays, are
`very smooth however.
`In another embodiment a thin diffusing lens may be
`set on the end of the casing serving as a light outlet
`surface, the diffusing lens dividing the light up evenly.
`Then it is sufficient if powdered glass is incorporated
`only into the diffusing lens. Furthermore, it is possible
`to tint either the glass disc only or the entire casing
`body with colour pigments in order to improve the
`contrast. A further increase in light output may be
`achieved if the light outlet surface is convexly curved in
`the shape of a lens. The diffusing lens may be shaped so
`that it has an outer flange by which it is mounted on the
`casing of the luminescence component or with which it
`may be tensioned.
`Referring now to the drawings, FIG. 1 shows the
`semiconductor body 4 of the light emitting diode fixed
`to the end of a supply pin 5. At the same time, one
`region of the semiconductor component is connected to
`this supply pin 5 so as to be electrically conductive. The
`second region of the semiconductor component is con
`nected so as to be electrically conductive, via a thin
`contacting wire 7, to the end face of a further contact
`pin 6 which runs parallel to the supply pin 5. The casing
`of the light-emitting diode is shaped like a plate and
`surrounds the ends of the supply pins 5 and 6 as well as
`the semiconductor component 4 with the supply wire 7.
`The casing comprises polycarbonates or epoxy resin,
`for example, and has a rectangular cross-section. Ac
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`cordingly the casing has two large outer surfaces lying
`layer of plastics to air by means of total internal reflec
`parallel to each other. The two narrow sides 2 of the
`tion. .
`casing also run parallel to each other at the part of the
`What is claimed is:
`casing bordering the light outlet surface 10. At the
`1. In a semiconductor luminescence component in
`height of the component and in a part lying thereabove,
`cluding a light-transmissive casing having an end sur
`these side surfaces 3 are angled so that the rays of light
`face serving as a light outlet surface, and a semiconduc
`8 originating laterally from the semiconductor compo
`tor light-emitting element cast in said casing opposite
`nent 4 are reflected at the smooth wall 3 and are de
`said light outlet surface, the improvement wherein said
`flected to the light outlet surface 10. The angle by
`casing has an upper casing part adjacent said light outlet
`which the side surfaces 3 are inclined in the lower part
`surface followed by a lower casing part in which said
`of this casing body is approximately 70° to the surface
`semiconductor element is located; wherein said upper
`carrying the semiconductor body. The light outlet sur
`casing part has a constant cross section; and wherein the
`face is formed by the end of the casing body remote
`side wall of said casing extends, in said lower casing
`from the semiconductor component. In order to obtain
`part, at such an angle to the light rays escaping laterally
`a uniform distribution of light, this end 10 is roughened
`from the semiconductor element and falling on the cas
`or is slightly structured on its surface. On the other
`ing side wall, that the light falling there is reflected back
`hand a diffusion plate 9 may be set on the end face 10,
`into the casing in a direction towards said casing end
`the diffusion plate ensuring uniform distribution of light
`surface serving as a light outlet surface.
`on the surface. The diffusing lens 9 contains 1 to 5%
`2. A component as defined in claim 1, wherein said
`powdered glass for better distribution of light as well as
`20
`casing has the shape of a plate in its upper part with a
`colour pigments for increasing contrast. If the diffusing
`constant rectangular cross-section, and tapers in its
`lens 9 is to be dispensed with, the particles of the pow
`lower part at least at two opposite side surfaces by an
`dered glass may be distributed in the casing body 1 in
`angle which is selected such that the meeting rays of
`the stated concentration, with the casing body also
`light falling thereon are reflected back into the interior
`preferably being tinted with colour pigment for the
`of the casing in a direction towards said light outlet
`purpose of increasing the contrast.
`surface.
`A casing body 1 is shown in FIG. 2 which is square
`3. A component as defined in claim 2, wherein said
`in its upper part and for example has a square cross-sec
`casing comprises two narrow sides running at an angle
`tion. With this type of casing, all four side surfaces 3
`of approximately 70° to a surface carrying said semicon
`may be tapered off in the lower part so that the light
`30
`ductor component in said lower casing part.
`falling on these surfaces is reflected back into the square
`4. A component as defined in claim 1, wherein said
`casing body. The lower casing part tapers preferably in
`casing comprises a square upper part and a tapered
`pyramid shape whereby the inclination of the side sur
`pyramid shaped lower part.
`.
`faces 3 is approximately 70°. The point of transition
`5. A component as defined in claim 1, wherein said
`between the square part of the casing 1 and the pyra
`35
`casing comprises a cylindrical upper part and a coni
`mid-shaped casing part must be selected so that the
`cally tapered lower part.
`largest possible part of the light escaping laterally from
`6. A component as defined in claim 5, wherein said
`the semiconductor body 4, which light runs parallel or
`lower part of said casing tapers conically at an angle of
`at a small angle only to the bearing surface of the semi
`conductor body, is reflected back to the light outlet
`approximately 70°.
`-
`•
`7. A component as defined in claim 1, wherein said
`surface 10. Thus it is ensured that as little light as possi
`casing comprises a polycarbonate or an epoxy resin and
`ble escapes through the side surfaces of the casing and
`contains 1 to 5% powdered glass for improving illumi
`thus is lost in terms of light output. .
`nation.
`Another embodiment is shown in FIG. 3 in which the
`8. A component as defined in claim 1, wherein said
`upper casing part is cylindrical. This casing part has a
`45
`light outlet surface is roughened and said remaining
`constant cross-section which is circular or eliptical. The
`casing surfaces are very smooth.
`lower casing part 3 tapers conically in a downward
`9. A component as defined in claim 1 and comprising
`direction whereby the tapering angle is again approxi
`a thin diffusing lens roughened at the surface, arranged
`mately 70°. The point of transition between the casing
`on the end of said casing and containing powdered glass
`part 1 and the casing part 3 is selected so that the largest
`and colour pigments for the purpose of improving con
`possible proportion of the light emitted laterally by the
`semiconductor body is reflected on to the end light
`traSt.
`10. A component as defined in claim 1, wherein said
`outlet surface of the luminescence semiconductor com
`light outlet surface is convexly curved in the shape of a
`ponent.
`With the embodiment of the casing body of a light
`11. A component as defined in claim 1, and compris
`emitting diode in accordance with the invention it is
`ing a diffusing lens with an outer flange for mounting
`possible to illuminate, in a unidorm manner, relatively
`said lens on said casing.
`large rectangular, square or round illuminating surfaces,
`12. A component as defined in claim 1 wherein the
`which are formed by the ends of the casing body. With
`side walls of said casing are smooth and said casing is
`one embodiment a good illuminated surface of the size
`formed of a plastic material such that the side walls
`10 × 10 mm can be obtained. The advantage of the
`define surfaces providing total internal reflection for
`arrangement in accordance with the invention lies in the
`fact that no special metalisation or reflecting coating
`impinging rays from said semiconductor element with
`need be applied to the reflecting wall surfaces. The
`out the need for an external reflective coating.
`reflection takes place in the present case at the border
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`lens.
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