JPS62145219A - Thin-film diode substrate for display device - Google Patents

Abstract

PURPOSE:To improve yield by forming a contact hole at a specific position after coating a diode with an interlayer insulating layer and forming an electrode newly on the interlayer insulating layer, bringing the electrode into contact with a lower layer electrode at the contact hole part, and using the newly formed electrode as an electrode for display. CONSTITUTION:A substrate 1, the 1st electrode 2, a light shield layer which prevents light from being incident on a semiconductor layer, the semiconductor layer 4 with PIN junction, the interlayer insulating layer 5 for insulating the 1st electrode 2 and the electrode 6 from each other, the 2nd electrode 6, and an interlayer insulating layer 7 which insulates the 2nd electrode and the 3rd electrode 8 are provided, and the 3rd electrode 8 is used as the display electrode. The interlayer insulating layer 5 is formed at the contact hole part 10 so as to make a ring-connection of the diode, and a contact hole part 11 is formed in the interlayer insulating layers 5 and 7 so as to connect the 1st electrode and the 3rd electrode 8. A hatched part encircled with a black frame is an effective display part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film diode for a display device that improves the display quality of a liquid crystal display device and expands the field of use of liquid crystals.

[Conventional technology]

Various display devices such as liquid crystal, EL, EC, FDP, and fluorescent displays have all reached the stage of practical use, and it can be said that the current goal is to display a high-density matrix. For display systems that have problems with multi-IJ drive, a so-called "active matrix" method using active additive elements is effective.

By using thin-film nonlinear resistance elements such as MIM and diodes in display devices, high-density and high-quality displays are possible, and thin-film nonlinear elements (active elements) are superior as active additive elements for display devices. It is well known. A diode element as an active element for a display device has a structure as shown in Fig. 7. In Fig. 7, 101 is a substrate;
102 is a first electrode, 106 is a semiconductor layer, 104 is an interlayer insulating layer, and 105 is a second electrode. 107 is an active element section;
108 is a contact hole portion.

[Problem that the invention seeks to solve]

However, in the conventional diode element shown in FIG. 7, the diode part, the wiring part for inputting signals to the diode, and the gaps between each wiring have signals different from those of the display electrodes, so they do not function as an effective display part. The effective display area of the display device was smaller than the total display area. The aperture ratio (effective display area/total display area) is a value often shown in liquid crystal displays, but when using the aperture ratio, it is about 70% to 80% when using active elements, and even larger In order to achieve this value, patterning accuracy and mask alignment accuracy are strictly required, which has the disadvantage of lowering yield and increasing cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a diode-equipped substrate for a display device that improves yield, is low in cost, and has a high density and a high aperture ratio.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention covers the diode with an interlayer insulating layer, then forms a contact hole at a predetermined position, forms a new electrode on the interlayer insulating layer, and connects the lower layer to the contact hole. The structure was such that the newly formed electrode was in contact with the electrode and used as the display electrode.

〔Example〕

FIG. 1 shows the structure of a thin film diode substrate for a display device according to the present invention.
is a cross-sectional view taken along line A-A' in Figure 1 (5), and Figure 1 (q is
Fig. 1 (This is a sectional view taken along line B-B of A. In Fig. 1,
1 is a substrate, 2 is a first electrode, 3 is a light shield layer for preventing light from entering the semiconductor layer, 4 is a semiconductor layer having a PIN junction, and 5 is a structure between the first electrode 2 and the second electrode 6. 6 is a second electrode; 7 is an interlayer insulating layer for insulating the second electrode 6 and the third electrode 8; 8 is the third electrode;
It is an electrode and is used as a display electrode. 10 is a contact hole portion of the interlayer insulating layer 5 formed for ring-connecting the diode, and 11 is a contact hole of the interlayer insulating layer 5 and 7 formed for connecting the first electrode 2 and the third electrode 8. Department. The area surrounded by a large black frame is the effective display area. FIG. 2 shows the structure of a thin film diode substrate for a display device when the present invention is not used.
A) is a plan view of the pixel section, FIG. 2 (Bl is a cross-sectional view taken along C-C in FIG.
FIG.

In FIG. 2, 21 is a substrate, 22 is a first electrode, 26 is a light shield layer, 24 is a semiconductor layer having a PIN junction, 2
5 is an interlayer insulating layer, 26 is a second electrode, 60 is a contact hole portion formed to connect the diode in a ring,
61 is a contact hole portion formed in the display electrode portion of the first electrode.

The hatched area surrounded by a large black frame is the effective display area.

Comparing FIG. 1 and FIG. 2, it can be seen that the effective display area in FIG. 1 is clearly larger. In addition, the contact hole between the third electrode 8 and the first electrode 2 in FIG. There is no need to strictly set the mask angle to 8 degrees.Furthermore, by making the first electrode 2, the second electrode 6, and the interlayer insulating layer 7 transparent, a bright display is possible. 3(A) is a plan view of the pixel portion, FIG. 3(B) is a cross-sectional view of FIG. 3(N), and FIG. 3(q is It is a sectional view of B-8 in the third position.

In FIG. 3, 41 is a substrate, 42 is a first electrode, 44 is a semiconductor layer having a PIN junction, 46 is a second electrode, and 47 is a connection between the first electrode 42, the second electrode 46, and the third electrode 48. An interlayer insulating layer for insulation, 48 a third electrode, and 51 a contact hole portion for connecting the first electrode 42 and the third electrode 48. In the embodiment shown in FIG. 3, the interlayer insulating layer 5, which requires strict mask alignment accuracy and patterning accuracy, in FIG. The purpose is to increase the resistance of the semiconductor layer on the electrode side, reduce the leakage current between the first electrode 42 and the second electrode 46, loosen the overall mask alignment accuracy and patterning accuracy, and improve yield and reduce cost. be.

Furthermore, in the second electrodes 6 and 46 shown in FIGS. 1 and 3, and in FIG. It is possible to prevent disconnection of electrodes or deterioration of the device during the process of forming devices, particularly liquid crystal cells, and to improve the durability of the diode, thereby improving reliability. FIG. 4 particularly shows the structure when the present invention is applied to a thin film diode substrate for enlarged transparent display, FIG. 4(A) is a plan view of the pixel portion, and FIG. 4 (q is a sectional view taken along B-8 in FIG. 4 (AJ). In FIG. 4, 61 is a substrate;
62 is a first electrode, 66 is a light shield layer, 64 is a semiconductor layer, 65 is an interlayer insulating layer, 66 is a second electrode, 67 is an interlayer insulating layer, and 68 is a third electrode, which is used as a display electrode.

70 is a contact hole formed for ring-connecting the diodes, and 71 is a contact hole for connecting the first electrode 62 and the third electrode 68. The hatched area surrounded by a large black frame is the effective display area. In FIG. 4, a light shield layer 66 is provided to prevent light from entering the semiconductor 64 in order to enlarge and transmit the image, and the second electrode 66 is replaced with an opaque electrode (metal film). ) to prevent light from entering. Furthermore, by arranging the gap between the third electrodes (display electrodes) 68 on the second electrode 66, a structure is created in which leakage of light at the gap is prevented and the contrast ratio is increased.

FIG. 5 shows an example in which the diode substrate of FIG. 4 is used, liquid crystal is formed into cells, and the liquid crystal shutter is used as a magnifying glass projection display device. In FIG. 5, 81 is a liquid crystal shutter unit made of a diode substrate, 82 is a liquid crystal shank cord for inputting signals to each liquid crystal shutter unit, 86 and 84 are polarizing plates, 85 is a green light, 86 is a liquid crystal shank cord for inputting signals to each liquid crystal shutter unit; is a red light, 87 is a blue light, 8
8 Light cord for inputting signals to each light, 8
9 is a power source that outputs a signal to each code, and 90 is a screen for displaying an enlarged image. Red, green, and blue lights 86, 85, 87 and a high-density liquid crystal shutter 81 are combined, and the liquid crystal shutter 81 and polarizing plate 86, 84 are separated so that the heat from the polarizing plate 86, 84 is not transmitted to the liquid crystal shutter 81, and By cooling the liquid crystal/shutter 81, even when high-intensity light is incident, a good transparent image can be obtained without impairing the performance of the liquid crystal.

FIG. 6 is a diagram showing a ring connection of diodes of the present invention.

〔Effect of the invention〕

As is clear from the above description, the present invention provides a first electrode,
A third electrode is formed in contact with the first or second electrode by a semiconductor layer having a PIN junction, a second electrode, an interlayer insulating layer, and a contact hole formed at a predetermined position in the interlayer insulating layer. By using three electrodes as display electrodes, good display can be achieved without making the overall mask alignment accuracy and patterning accuracy strict. Furthermore, by utilizing the present thin film diode substrate in a liquid crystal display device, high-density display, large-sized display, and enlarged transparent display become possible, and it is believed that the present invention will contribute to the development of liquid crystal display devices.

[Brief explanation of drawings]

1, 3, and 4 show the structure of the display part of the thin film diode substrate for a display device of the present invention, and FIG.
Figure 3 (Al) and Figure 4 (Al are the plan views of the pixel section, respectively, Figure 1 (Bl (q), Figure 3 (B) (C) and Figure 4 (Bl (C) are the plan views of the Figure (~, Figure 3 (
5) and Figure 4 (A-A, B-B cross-sectional view of N, Figure 2 shows the structure of the display part of a conventional thin film diode substrate for display devices, Plan view, Figure 2 (Bl
(C) An explanatory diagram showing an enlarged transparent display system using the thin film diode substrate for a display device of the present invention, FIG.
FIG. 7 is a circuit diagram showing diode ring connection, and a cross-sectional view showing the structure of a general thin film diode for display devices. 1... Substrate, 2... First electrode, 6...
...Light shield layer, 4...Semiconductor layer, 5.
...Interlayer insulating layer, 6...Second electrode, 7.
...Interlayer insulating layer, 8...Third electrode patent applicant Citizen Watch Co., Ltd. 1"?+-':"" -
! ,”':,. Figure 1 z knee\. Figure 2 Figure 3 (C)

Claims (4)

[Claims] (1) A first electrode formed on a substrate, a semiconductor layer having a PIN junction formed on the first electrode, a second electrode formed on the semiconductor layer, and the first electrode or , an interlayer insulating layer having a contact hole on the second electrode, and the contact hole in the interlayer insulating layer
A thin film diode substrate for a display device, characterized by having a third electrode in contact with the electrode. (2) The thin film diode substrate for a display device according to claim 1, wherein the thin film diode is connected in a ring. (3) At least one of the first electrode and the second electrode, and a third
2. A thin film diode substrate for a display device according to claim 1, wherein the electrodes are made of a transparent conductor. (4) The thin film diode substrate for a display device according to claim 1, wherein the third electrode is a display electrode.