JPS6022179A - Light emitting diode display - 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 (Technical Field) The present invention relates to a high-definition, large-capacity, low-voltage display device, and particularly to a light-emitting diode display device that achieves this at low cost.

(Prior Art) As shown in FIG. 1, a conventional display device using light emitting diodes includes an insulating substrate 11, a light emitting diode chip 2, a vertical wiring 3 electrically connected to one terminal of the light emitting diode chip 2, It consists of an insulator 4 made of hardened epoxy resin or the like, and a horizontal wiring 5 electrically connected to the other terminal of the light emitting diode chip.

The purpose of the above-mentioned conventional technology is to arrange the individual light emitting diode elements one by one on a substrate,
This realizes a two-dimensional large screen display device. However, since it is assumed that the light emitting diodes, which are display elements, are physically separated from each other up to at least the part including the PN junction surface, the process of wiring the rows and columns for the matrix spring is complicated and expensive. It was also expensive.

(Object of the Invention) In order to eliminate these drawbacks, the object of the present invention is to provide a plurality of parallel band-shaped electrodes perpendicularly to each other on the light emitting surface and the back surface of a light emitting diode consisting of a large-area PN junction. a plurality of strip-shaped thin film layers forming a second PN junction with the base of the light emitting diode between the parallel strip-shaped electrodes;
Further, it is an object of the present invention to provide a light emitting diode display device with high definition, large capacity, and simple structure, which is formed by providing a strip-shaped auxiliary electrode on the strip-shaped thin film layer, and will be described in detail below.

(Embodiment of the Invention) FIGS. 2, 3, and 4 are diagrams for explaining a first embodiment of the present invention.

First, Fig. g2 shows a light emitting diode display device according to the first embodiment of the present invention.

In Figure 2, 401 is an N-type GaAsxPl-X (0(x('1)) substrate, and 4θ2 is an N-type GaAsxP1-
x A uniform P-type layer formed on one side of the substrate, 403 is an N-type layer aA sz P 1-x A number of parallel strip-shaped P-type layers with a predetermined width on the other side of the substrate, 40
4 is a strip-shaped anode electrode having a predetermined width on the P-type layer 402, 405 is a strip-shaped cathode electrode having a predetermined width on the N-type layer 401, and 406 is a strip-shaped cathode electrode having a predetermined width on the second P-type layer group 406. It is an auxiliary electrode with This light-emitting diode matrix panel is different from the conventional one in which the light-emitting diode elements serving as each pixel point are formed physically independently as shown in FIG. Furthermore, desired PN junctions 402, 403 and electrodes 404, 405, 406 can be formed all at once using only general semiconductor manufacturing equipment. Before explaining the operation of this panel, we will explain the electrode i4 during high-speed, large-current operation in Figure 3.
Turn dependence will be explained using the case of this panel.

In FIG. 3, the arbitrary N-type layer 4 of the strip-shaped anode electrode 404
01 and the P-type layer 402 in the forward direction through a current limiting resistor (R1) and a switch S that controls the energization time, and then the switch S is connected for a predetermined short time. The light-emitting area obtained when the opening is closed is a portion 402 indicated by ■■ in FIG. This means the following.

(1) The thickness of the N-type layer 401 is approximately 171 μm compared to approximately 400 μm.
In the P-type layer 402 having a thickness of approximately 00 times, separation between the band-shaped anode electrodes 404 is possible.

(2) In the N-type layer 401, which is about 100 times as thick as the P-type layer 402, the strip cathode electrode 40
Separation of 5 is not possible.

The intended display of this display device is that in such a case, the display can be performed by selectively emitting light only at the intersection where the selected X and Y electrodes intersect, so this display device cannot be used as is. . Figure 4 shows the first embodiment of the present invention.
4, the operation of the first embodiment of the present invention will be described in detail, focusing on the effect of the auxiliary electrode 403, which is the third electrode. The light emitting diode display device shown in FIG. 4 includes, in addition to each part of the light emitting diode matrix panel explained in FIG.
4 side switch SX1 + SX2 r...SXn,
Switch S Yl-s on each strip cathode electrode 405 side
S Y2 s...SY, power supply E1, current limiting resistor R
1% power source E2, current limiting resistor R2, control unit 408, switch S X 1 * based on control from the control unit 408
S x2...X selector 4 that turns SX on and off
09, switch SY based on the control of the control unit 408
1, SY2 t... Consists of each part of the Y selector 410 that turns on and off SYm.

In FIG. 4, in addition to the external three-part circuit shown in FIG.
A negative voltage of the power source E2 is supplied through the second PN junction 411 between the second P-type layer 403 and the N-type layer 401.
Under such electrical conditions, for example, open the switch 5X218Y3 for a short time to connect the first P-type layer 402 and N-type layer 4Ql. The operation when flowing I unidirectional current to the PN junction 412 is as follows.
Due to the reverse bias effect of the second PN junction 411, a space charge layer (depletion layer 2:) is generated in the N-type layer 401 near the second PN junction 411.
One selected electrode Y of the strip cathode electrodes 405
The injected electrons ○ move directly upward as shown by arrows in the figure, avoiding the barrier of the depletion layer 2. Finally, the electrode X passes through the first PN junction 412 near one selected electrode
reach. Therefore, as a result, the current in the jI direction flows selectively only in the area where the electrodes X and Y intersect, and 1. Only the portion indicated by P in FIG. 4 will emit light.

As explained above, instead of constructing a large number of light emitting diode elements mechanically or geometrically separated one by one, one large area light emitting diode is constructed on both the front and back principal surfaces. By forming a large number of predetermined simple matrix electrode lines, it is possible to obtain a matrix consisting of a large number of light emitting diode elements two-dimensionally, and only one type of external electrical conditions are required for driving. It is sufficient to prepare a reverse bias power source for the PN junction, which requires almost no power, and there is an advantage that a large capacity light emitting diode display device can be easily realized at a low cost.

In the first embodiment, N-type GaAsxP4. -
Even if the configurations of the layer and the P layer are completely reversed and the potential applied to the auxiliary electrode is positive, exactly the same effect will be produced. Further, as the N- or P-type substrate, other ■-■ group compound semiconductors such as GaAs*GaP, AtP, AAAs, or mixed crystals containing these may be used.

(Effects of the Invention) The present invention enables large capacity and high performance by forming a large-area PN junction in a plane on a compound semiconductor substrate and forming anodes, cathodes, and auxiliary electrodes in the matrix direction. Since a display device with high brightness, high reliability, and low voltage can be obtained at a low cost, it can be used in the field of display devices for all electronic devices.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional light emitting diode display device, and FIGS. 2 to 4 are diagrams for explaining a first embodiment of the present invention. 401...N-type GaAS1-xPn (0<X<1)
Substrate (N-type layer), 402...first P-type layer, 403...
- Second P-type layer, 404... strip-shaped anode electrode, 40
5... Strip cathode electrode, 406... Auxiliary electrode, 4
0B...Control unit, 409...X selector, 410.
・・Y selector, SX, ~SXn, sy, ~SYm...
・Switch, El + E2...Power supply, R1r R2
...Current limiting resistance. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A substrate of an N-type (or P-type) compound semiconductor, a thin film layer of the P-type (or N-type) compound semiconductor laminated on one metal surface of the substrate, and a thin film layer on the thin film layer. a plurality of first strip-shaped electrodes formed in parallel to the substrate; a plurality of second strip-shaped electrodes formed on the other surface of the substrate in parallel in a direction perpendicular to the first strip-shaped electrodes; a plurality of strip-shaped thin film layers of P-type (or N-type) compound semiconductors formed between the second strip-shaped electrodes; a third strip-shaped electrode formed on each of the strip-shaped thin film layers; and the third strip-shaped electrodes. a first power source whose negative electrode (or positive electrode) is connected to the electrode and whose positive electrode (or negative electrode) is connected to the second strip-shaped electrode; Selectively connect the positive electrode (or negative electrode) of the second power source to the strip-shaped electrode, and connect the negative electrode (or positive electrode) of the second power source to the second strip-shaped electrode corresponding to the position where light is to be emitted. A light emitting diode display device comprising a switch means.