JPS63250183A - Light emitting diode display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Background of the Invention Light emitting diodes (LEDs) are generally mounted on a pair of electrodes or terminals and encapsulated with a transparent coating material, which may be a transparent or colored epoxy resin. It consists of coated or dip-coated semiconductor chips. When a bias voltage is applied to LE[), it produces visible light. Because of its small size, relatively high durability, and relatively low power consumption, it replaces resistive filament type lamps in many applications. However, LEDs only produce a very limited amount of light or a limited intensity of light, and increasing the size of the conductor chip or increasing the bias voltage will not result in any practical improvement in their light-emitting capabilities. I won't give it.

Analysis shows that the coating on the semiconductor chip of an LED unit tends to absorb some of the light emitted by the chip, thereby reducing the amount of visible light produced by the LED unit. In order to do this, the known LED lo shown in FIG. It is encapsulated with a transparent epoxy coating 13 called epoxy. In this arrangement, a portion of the light that would be lost in an LED unit without a reflector is reflected to become visible, and the total amount of visible light produced by the LED unit is improved.

Nevertheless, even with the above-mentioned improvements, the considerable amount of light emitted by semiconductor chips still cannot be completely converted into visible light.

Therefore, it is a primary object of this invention to provide an improved LED display that provides a relatively large amount of visible light.

Another object of this invention is to provide an improved LED display device that provides better display capabilities at a relatively low cost.

SUMMARY OF THE INVENTION The LED display device of the present invention generally comprises a semiconductor chip capable of emitting visible light when a voltage is applied, the semiconductor chip is fixedly mounted on a pair of electrodes, and the semiconductor chip is fixedly mounted on a pair of electrodes. A reflector is provided having a cylindrical cavity. The cylindrical cavity of the reflector is filled with a transparent material, such as an epoxy resin, and the upper portion of the filled material is formed into a solid coating, generally in the shape of a hemispherical or parabolic shape. In a preferred embodiment, the reflector has a generally flat upper surface;
And in other preferred embodiments, the reflector has an arcuate concave upper surface. In yet another preferred embodiment, the reflector is provided with a plurality of cylindrical cavities, each of which includes one or more semiconductor chips, and each of the cylindrical cavities is provided with a respective solid transparent hemispherical coating. , which is optionally integrally connected with another hemispherical cladding to form the LED display into an integral solid state unit.

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the LED display device of the invention is schematically illustrated in FIGS. 2 and 3. FIG. 20 LED display devices
(FIG. 2), a base plate 21 having a pair of electrodes 22 in the form of printed wiring; a cylindrical cavity 25 in which a semiconductor chip 23 mounted on the pair of electrodes 22; It consists of a generally disk-shaped reflector 24 having a cylindrical opening to form a cylindrical opening, and a generally hemispherical solid cladding 26 filling the cylindrical cavity 25 to enclose the semiconductor depth 23. The solid coating 26 is made of a transparent material such as an epoxy resin that may be selectively colored or uncolored, and forms a generally hemispherical protrusion over the cylindrical cavity 25 in which the semiconductor chip 23 is placed. The base plate 21 also has a pair of mounting protrusions 28 electrically connected to a pair of electrodes 22 .

In order to make the LED display device shown in FIG.
3 is the electrode 2 of the base plate 21 which is a printed wiring board.
2 is first attached. The base plate 21, onto which the semiconductor chip 23 is easily mounted, is then placed in a first mold, not shown, and the reflector 24 is then placed in a first mold, not shown.
is placed on the base plate 21 and the cylindrical cavity or opening 25 is aligned or positioned to mount the semiconductor chip 23. A second mold with a cavity of the same shape as the solid coating 26 is then placed between the semiconductor chip 23 and the reflector 2.
4 is placed with the hollow side down on top of the first mold so as to cover the base plate 21 with the mold. A coating material in liquid state, which may be an epoxy resin, is then filled into the cavity of the second mold through a filling gate of the second mold, not shown. A final curing process is performed to harden the coating material and complete the LED display coating mold.

In the first embodiment, an LED device is illustrated with a reflector having only one cylindrical cavity, but a plurality of reflectors are also provided to correspond to a plurality of LED chips mounted on a base plate. cylindrical cavities may be provided,
And it should be understood that each cylindrical cavity is provided with a hemispherical solid coating 26.

FIGS. 4 and 5 show a second example of the LED display device of the present invention.
, which includes a hemispherical solid coating 2 filling a cylindrical cavity 25 to encapsulate a semiconductor chip 23.
6 is the same as the first embodiment except that it has an outskirt 27 that covers the entire reflector 24, and the reflector 24 has a notch or m1 opening 2 as shown in FIG.
9 may be provided, whereby the coating material 26 is bonded to the base plate 21 so as to fix the reflector 24 on the base plate 21 without using a separate adhesive method for gluing the reflector i 24 on the base plate 21. Can be contacted or adhered to.

FIG. 6 shows a third embodiment of the LED display device of the present invention. In this embodiment, a reflector 24A having an arcuate concave upper surface 24B as shown in FIG. 7 is used instead of having a planar upper surface as in the first embodiment. The generally hemispherical solid coating 26 covers the entire area or portion of the cylindrical cavity or aperture 25 and the concave surface of the reflector 24A. The arrangement of the cylindrical cavity or opening 25 for placing the semiconductor chip 23 therein remains as in the first embodiment.

In use, a portion of the light emitted by the semiconductor depth 23 is randomly reflected by the cylindrical wall surface of the cylindrical opening 25, and the randomly reflected light is randomly emitted through the hemispherical covering 26. The light that is randomly reflected and emitted and the remaining part of the light that is emitted directly from the semiconductor chip 23 is the effective visible light emitted by the LED without a reflector, which has a cylindrical cavity in which the semiconductor chip is placed.
Make it bigger than.

8 and 9 show a fourth embodiment of the LED display device of the invention, which comprises a base plate 21 having on one side a plurality of pairs of electrodes 22A in the form of printed wiring; is mounted on each pair of electrodes 22A, and a plurality of semiconductor chips 23-23 are arranged in such a manner that each of the semiconductor chips 23 is disposed in one cylindrical opening 25. a generally circular reflector 24R having a corresponding plurality of cylindrical apertures 25-25, each cylindrical aperture 25 being filled with a solid coating material, which also includes a respective respective cylinder 24R having a semiconductor chip 23 therein. formed into a generally hemispherical protrusion 26 over the aperture 25;
The hemispherical protrusions 26 are provided with an outskirt 27-27 connecting the hemispherical protrusions 26-26 to form an integral covering over the entire reflector 24R. A notch 29 is conveniently provided on the reflector 24R to ensure that the material is in contact with the base plate 21, so that the reflector 24R has a separate bond for bonding the reflector 124R onto the base plate 21. It is fixed on the base plate 21 without the need for any method.

FIG. 10 shows the improved LE[) display of this invention.
A fifth embodiment of the device is shown, which includes a base plate 21 having a plurality of semiconductor chips 23, a circular reflector 24L having a plurality of cylindrical openings 25 corresponding to the semiconductor chips 23, and a plurality of reflectors 24L. 2 cylindrical openings
5 and a concave arcuate upper surface 248 coated with a solid transparent coating having a plurality of protrusions 26 corresponding to 4-i. This embodiment is the same in construction as the third embodiment except that the upper surface of the reflector is concave. The device of this embodiment provides better results in reflecting the light emitted by the LED.

Although the preferred embodiment employs a cylindrical cavity or aperture, the cylindrical cavity or aperture may be replaced by an inverted conical cavity or aperture to provide different visual performance of the device. It should further be noted that the integral formation of a solid transparent coating with multiple protrusions provides better mechanical integration and reduces manufacturing costs.

Although the preferred embodiment has been illustrated and described using one semiconductor chip in each cylindrical cavity and a generally circular reflector, one semiconductor chip in each cylindrical cavity is used to increase the intensity of the light.
It should be understood that more than one semiconductor chip can be placed and the reflector can be rectangular or any other shape. Other modifications may be made without departing from the scope and spirit of the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a conventional LED unit. FIG. 2 is an enlarged schematic cross-sectional view of the first embodiment of the LED display unit of the present invention. FIG. 3 is an enlarged exploded perspective view of the LED display unit of FIG. 2 without a solid coating. FIG. 4 is an enlarged schematic sectional view of a second embodiment of the LED display unit of the present invention. FIG. 5 is an enlarged exploded perspective view of the LED display unit of FIG. 4 without a solid coating. FIG. 6 is an enlarged schematic cross-sectional view of a third embodiment of the LED display unit of the present invention. 7 is a perspective view of a reflector employed in the LED display unit of FIG. 6. FIG. FIG. 8 is an enlarged schematic cross-sectional view of a fourth embodiment of the LED display unit of the present invention. FIG. 9 is an enlarged exploded perspective view of the LED display of FIG. 8 without a solid coating. FIG. 10 is an enlarged schematic cross-sectional view of a fifth embodiment of the LED display device of the present invention. In the figure, 10.20 is an LED, 12.24 is a reflector, 13.26 is a coating, 21 is a base plate, 22 is an electrode, 23 is a semiconductor chip, 25 is a cavity, 27 is an outskirt, 28 is a protrusion, 29 is a notch or opening. Procedural amendment (formality) 1. Indication of the case Patent Application No. 7576.5 of 1988 2, Title of the invention 1 Indication device 3, Person making the amendment Relationship with the case ° Patent applicant address Qinhua South Road, Taipei City, Taiwan, Republic of China 253L12
tl1 Name: Taipei Guangbo Electronics Co., Ltd. Representative: Zheng Yuwen 4, Agent address: 2-8-1 Hirano-cho, Higashi-ku, Osaka City, Hirano-cho Yachiyo Building voluntary amendment 6, drawing plan subject to amendment 7, amendment As per the attached sheet. That's all 10 Figure 2 Figure 3 Figure 4 Flash 91!11

Claims (6)

[Claims] (1) a semiconductor chip capable of emitting visible light when a voltage is applied; a pair of electrodes to which the semiconductor chip is mounted; a reflector having a cylindrical hole in which the semiconductor chip is disposed; a solid coating formed in a generally hemispherical protrusion over a cylindrical hole, the solid coating having a portion filling the cylindrical hole. (2) The light emitting diode display device according to claim 1, wherein the solid coating has an outskirt that covers the entire reflector. (3) wherein the electrode is formed in printed wiring on a base plate and the reflector has an aperture allowing the solid coating to extend therefrom into contact with the base plate. The light emitting diode display device according to item 2. 4. The light emitting diode display of claim 3, wherein the reflector has an arcuate concave upper surface. (5) A light emitting diode display device including a base plate, a plurality of pairs of electrodes formed in printed wiring on one side of the base plate, and a plurality of semiconductor chips, each of which is supplied with a voltage. a reflector capable of emitting visible light and soldered onto a respective pair of each of said pairs of electrodes and further having a plurality of cylindrical holes corresponding to said semiconductor chip; A reflector is fixed on the base plate, each of the plurality of semiconductor chips is disposed in a corresponding one of the plurality of cylindrical holes of the reflector, and further covers the reflector and is mounted on the base plate. a solid transparent coating securing said reflector to said solid transparent coating, said solid transparent coating defining said cylindrical aperture and a plurality of generally hemispherical protrusions;
Filling over and corresponding to the cylindrical holes, the solid transparent coating is integrated with the plurality of hemispherical protrusions.
A light emitting diode display device formed into a single integrated unit. (6) The light emitting diode display device according to claim 1 or 5, further comprising a plurality of semiconductor chips arranged in one cylindrical hole of the reflector.