JPS62253193A - Matrix type display unit - 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 Field of Industrial Application The present invention relates to a matrix type display device that has high display quality and is capable of displaying a large capacity.

Furthermore, specifically, it is a matrix type display device using non-linear elements.

BACKGROUND OF THE INVENTION Conventionally, in matrix type display devices with non-linear elements that have been proposed, the display medium is most often liquid crystal. Therefore, a matrix type liquid crystal display device will be explained below as an example.

The field of application of liquid crystal display devices is expanding from displays for watches, calculators, etc. to displays for terminals and video displays, but what is required is the ability to realize high-quality, large-capacity displays. The methods include (1) simple matrix method;
(2) There is an active matrix method, and (2) further includes (2a) a method using a three-terminal element such as a thin film transistor (TPT), and (2b) a method using a non-linear two-terminal element. Each method has its advantages and disadvantages; method (1) has a problem with display quality, and method (2a) has a drawback that the manufacturing process is complicated and the cost is high. (2b) is an easier process than (2a) and can reduce costs.

There are two main types of matrix type liquid crystal display devices with non-linear elements.

The first one is a device using an element as shown in FIG. [I Triple E, Transaction,
Electron, Devices, Edie Volume 28, No. 6, 7
Page 36 (1981) (I [! Anal TR to N5A-
CTTON ON ELECTRON IIEV
ICES Vol, ED-28, Na6, 736 (1
981)) Figure 3fa) is a cross-sectional view of the configuration of a non-linear two-terminal element, and Figure 3(b) is a layout diagram of a liquid crystal display substrate using this. In the same figure (al), 101 is a substrate, 102 is a tantalum (Ta) layer, and 103 is about 400 mm thick.
~700 tantalum oxides ("r" az 05 ) obtained by anodic oxidation, 104 are pixel electrodes, 10
5 is a chromium (Cr) layer;
06 is a non-linear one-terminal element, 107 is a bus bar, 108
is a terminal, and 109 is a picture element electrode.

The second one is a device using an element as shown in FIG. [Television Society Technical Report, May 2, 1982
Announced on the 5th] This is two pieces of amorphous silicon (a-
3i) A non-linear element is realized by forming a configuration in which PIN diodes are connected in a ring shape in parallel and opposite directions. Figure 4 (Al is a cross-sectional view of the structure of this element, and Tbl in the same figure is a layout diagram of a liquid crystal display substrate using this element. In this figure, the PIN diode represents a normal PN diode. In Fig. 4, 201 is a substrate, 202 is a first electrode, 203 is an N-type a-3i, 204
is an I type a-3i, 205 is a P type a-3i, 206 is a chromium layer, 207 is a protective layer made of an insulator, 208 is a second electrode, 209 is a PIN diode connected in a ring shape, 2
10 is a bus bar, and 211 is a picture element electrode.

By using these non-linear resistance elements, it is possible to realize a display capacity much larger than that of a normal liquid crystal display. Expressed in terms of duty ratio, driving is possible even with a duty ratio of about 1/1000.

Problems to be Solved by the Invention When considering driving a display device using a non-linear two-terminal element, it is necessary to apply a sufficient voltage to the non-linear element. The capacitance must be designed to be about 1/10 or less of that of the picture element portion. However, in the first type of non-linear element according to the conventional technology mentioned above, the shape of the element is made fine because tantalum oxide has a high dielectric constant of 20 or more, but this significantly deteriorates the yield. It is the cause of this.

Adding to this is the fact that the manufacturing process includes at least three complex and time-consuming photolithography steps.

Next, in the second example of the non-linear element, one photolithography step is included at least five to six times.

This reduces the yield in production and increases production costs.

Therefore, there is a need for a device that can be manufactured through simple steps and has sufficiently large nonlinear current-voltage characteristics.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a pair of conductor layers having a gap, formed of a compound of arsenic (As) and selenium (Se), on a substrate. The present invention provides a matrix type display device having an element having a structure in which a semiconductor layer and a conductor layer are laminated.

Operation The present invention realizes an element exhibiting nonlinear current-voltage characteristics with the above-described configuration. This nonlinearity is caused by the barrier layer effect at the junction between the semiconductor layer and the conductor layer.
It is assumed that there are. When measuring the current-voltage characteristics of an actual element, it shows a characteristic that can be returned in the form T=A.■α. Here, A and α are constants. By interposing this element between the bus bar and each picture element electrode, it is possible to increase the ratio of the on voltage to the off voltage applied to the picture element part, making it possible to improve contrast characteristics. becomes.

Furthermore, the manufacturing method of the non-linear element used in the display device according to the present invention is very simple. That is, the semiconductor layer and the upper conductor layer can be laminated on the lower conductor layer patterned on the substrate by successive vapor deposition using one mask.

Furthermore, since the compound of arsenic and selenium forming the semiconductor layer has a relatively small dielectric constant of 10 or less, the shape of the nonlinear element according to the present invention can be made relatively large.

From the above two points, an improvement in manufacturing yield can be expected.

EXAMPLE Hereinafter, an example of a matrix type display device of the present invention will be described with reference to the drawings.

As mentioned above, liquid crystal is the most commonly used display medium in matrix type display devices using non-linear elements, so the following description will mainly focus on liquid crystal display devices.

Further, in the following embodiments, the lower conductor layer 13, bus bar 12, and picture element electrode 15 shown in FIG. 2 were formed of the same material. In particular, when voltage attenuation due to electrode resistance is a problem, a highly conductive material may be used for the bus bar 12.

First, an example of the manufacturing process of a matrix type liquid crystal display panel with non-linear two-terminal elements will be described.

Obtain soda glass with transparent electrodes etched into a predetermined pattern, immerse this substrate in fuming nitric acid, wash with water, and dry.

Next, a mask made of a magnetic stainless steel plate with a thickness of about 30 μm with holes in a predetermined pattern and the substrate described in 1.
A Gohardt magnet was placed to bring the metal mask and substrate into close contact. This was placed in a vacuum chamber for vapor deposition, and a film was formed on the substrate by a resistance heating method. As a result, a substrate as shown in FIG. 2 was obtained.

Describe the vapor deposition method in detail. There are 4 molybdenum (MO) evaporation sources around the bottom of the vacuum chamber and 1 in the center, 5 in total.
It was installed so that each unit could be heated independently. The upper conductor layer material is placed in the central evaporation source, and the semiconductor layer material and appropriate amounts of arsenic and selenium compounds are placed in the four surrounding evaporation sources. The substrate was placed in the upper center of the vacuum chamber. Inside the tank I x 10-'Torr
When the air is exhausted to a certain level, one of the surrounding evaporation sources is heated, the shutter is opened, and when a predetermined film thickness is deposited, the shutter is closed. The film thickness was detected using a film thickness monitor using a crystal resonator. Subsequently, the surrounding evaporation sources were heated one after another, and each evaporation source was evaporated to the same thickness. Next, the central evaporation source was heated to deposit the film to a predetermined thickness. As a result, as shown in FIG. 1, it was possible to form an element having a structure in which the upper conductor layer was attached to the inside of the island on the island-shaped thin film of the arsenic and selenium compound semiconductor.

Before forming this substrate into a panel, the current-voltage characteristics of the device were measured.

Furthermore, after forming an alignment film on the substrate on which the non-linear two-terminal element was formed and the counter substrate on which the band-shaped transparent electrode was formed, they were subjected to a rubbing treatment, and the two substrates were bonded together to form a panel. and injected liquid crystal. The rubbing direction is
The liquid crystal molecules were designed to have a 90° twisted structure.

Through the above process, a liquid crystal display panel with a nonlinear two-terminal element was obtained.

(Example 1) A liquid crystal display panel with two non-linear terminals as shown in FIG. 1 was manufactured. The manufacturing method is as shown above.

Substrate 1 includes silicon dioxide (S +
A material coated with Oz) was used. The lower conductor layer 2 is 20
It was formed of two types: ITO and titanium (Ti) with a thickness of 0.00 mm. For each of them, the semiconductor layer 3 is a compound of arsenic and selenium, and the amount of arsenic is 1 atomic %, 5 atomic %, 10 atomic %,
25 atom%, 40 atom%, 50 atom%, 60 atom%, 8
Approximately 10001 of 9 types of 0 at% and 85 at%
It was vapor deposited. Furthermore, the upper conductor layer 4 has a thickness of approximately 50 mm.
0 tellurium films were formed.

The non-linearity of the current-voltage characteristics of the device was as significant as α-7 to α-15. Moreover, its capacity was also sufficiently small compared to the capacity of the liquid crystal layer.

A liquid crystal display panel was manufactured using these substrates, and the duty ratio was 1/1000. During matrix driving with a bias ratio of 1/7, a display with a contrast of 10:1 or more was achieved.

By the way, in the panel manufacturing process, it is necessary to heat the substrate to at least 90° C. during liquid crystal injection, alignment film formation, etc., but the arsenic component ratio of the arsenic and selenium compound constituting the semiconductor layer 3 is 10. The vitrification temperature of the element with no grooves at % was considerably lower, and the element was destroyed during heat treatment. Further, in a device with an arsenic component ratio of 85 atomic %, arsenic precipitation was observed, making it impractical.

From the above, it has been found that a compound of arsenic and selenium has satisfactory characteristics as a non-linear two-terminal element for a liquid crystal display device if the component ratio of arsenic is 10 atomic % or more and 80 atomic % or less. did.

(Example 2) A liquid crystal display panel with a nonlinear two-terminal element as shown in FIG. 1 was manufactured by the manufacturing method described above.

As the substrate 1, soda glass whose surface was coated with silicon dioxide (SiC2) was used. The lower conductor layer 2 has a film thickness of approximately 150 mm.
Two types of ITO or titanium were formed. For each, tellurium was used as the constituent material of the upper conductor layer 4, and the film thickness was approximately 200, 300, and 5.
00 people, 1000 people, 2000 people, 3000 people, 400 people
0, 5,000, and 8,000 people] species were vapor-deposited. The semiconductor layer 3 is made of diarsenic triselenide (A 32 S
83) was deposited approximately 20,001 times.

Electrical measurements were performed on the device under these conditions, but the nonlinearity of the current-voltage characteristics was extremely large, and the capacitance was smaller than the capacitance of the liquid crystal layer in the picture element electrode connected to the device. It was small enough.

When a liquid crystal display panel was manufactured using these substrates, the display contrast was 10=1 or more during matrix driving with a duty ratio of 1/1000 and a bias ratio of 1/7.

(Example 3) A liquid crystal panel with a nonlinear two-terminal element as shown in FIG. 1 was manufactured according to the manufacturing method described above.

As the substrate 1, soda glass whose surface was coated with silicon dioxide (Sing) was used. The lower conductor layer has a thickness of approx. 2
Two types of ITO and titanium were prepared for 500 people. For the two types, the upper conductor layer 4 is made of chromium (Cr), aluminum (Al), and titanium (Ti) with a film thickness of about 500, 1000, and 2000, respectively.
Three types were formed.

As the semiconductor layer 3, monoarsenic triselenide (ASS133
) was deposited approximately 20,001 times.

The electrical characteristics of the device manufactured under these conditions were measured, and the nonlinearity of the current-voltage characteristics was large, and the capacitance was sufficiently small, making it suitable for matrix drive. A liquid crystal display spring was fabricated using these substrates. During matrix driving with a duty ratio of 1/1000 and a bias ratio of 1/7, the display contrast was 10:1 or more.

(Example 4) According to the manufacturing method described above, a liquid crystal display panel with a nonlinear two-terminal element as shown in FIG. 1 was manufactured.

As the substrate 1, soda glass whose surface was coated with silicon dioxide (SiOz) was used. As the lower conductor layer 2, chromium (Cr) and aluminum (Al) with a film thickness of approximately 2000 mm are used.
Or tin oxide (SnO□) containing antimony (Sb)
formed. On top of that, as a semiconductor layer 3, 3 selenide 2
As the upper conductor layer 4, arsenic (A S is e 3) with a thickness of about 2,000 layers, and tellurium with a thickness of about 500 layers,
The layers were sequentially deposited by resistance heating.

The electrical characteristics of the device produced under the above conditions showed significantly nonlinear current-voltage characteristics, and the capacitance was sufficiently small.

When a matrix type liquid crystal display panel was manufactured using these substrates, the display contrast was 10: when driven at a duty ratio of 1/1000 and a bias ratio of 1/7.
There were more than 1.

(Example 5) According to the manufacturing method described above, a liquid crystal panel with a non-linear two-terminal element as shown in FIG. 1 was manufactured.

As the substrate 1, soda glass whose surface was coated with silicon dioxide (SiOz) was used. Two types of lower conductor layer 2 were prepared: ITO and titanium, each having a film thickness of about 2000 yen. For the two types, diarsenic triselenide (As2Se3) is used as the constituent material of the semiconductor layer 3, and the film thickness is approximately 300, 500, 1000, and 200.
0 people, 3000 people, 4000 people, 5000 people, 6000 people
A total of 8 types of humanoids were obtained by vapor deposition. Furthermore, a tellurium film having a thickness of approximately 400 mm was formed thereon as a two-part conductor layer 4.

The electrical characteristics of the devices manufactured under the above conditions all showed significantly nonlinear current-voltage characteristics, and the capacitance was sufficiently small.

When a matrix type liquid crystal display panel was manufactured using these substrates with non-linear elements, the duty ratio was 1/10.
00 and a bias ratio of 1/7, it showed good display quality with a display contrast of 10:1 or more.

In Examples 1 to 5, a method using a metal mask was used to pattern the semiconductor layer and the upper conductor layer, but elements with similar shapes could also be obtained by a lift-off method using a photoresist. .

In addition, FIG. 2 shows non-linear elements (al single stage, (bl
Although a two-stage structure is shown (in principle, a configuration with three or more stages is conceivable), as the number of stages increases, the dark value of the nonlinear characteristic can be increased. The optimum configuration should be selected in relation to the darkness value of the liquid crystal material.

Furthermore, although we took liquid crystal as an example of the display medium, similar effects can be obtained by using other devices such as electroluminescent devices (EL), electrophoretic devices, electrochromic devices, and plasma light emitting devices. Needless to say.

Effects of the Invention As explained above, the non-linear two-terminal element of the present invention has a simple structure, so it can be manufactured at a high yield, and furthermore, it has excellent non-linearity in terms of current-voltage characteristics. ing. Therefore, a matrix type display device using the element according to the present invention is capable of displaying a large capacity and can also realize good display quality.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a non-linear two-terminal element used in a matrix-type display device according to the present invention, and a plan view of the non-linear two-terminal element (al structure); FIG. Figure 3 (al and figure 4 fat are cross-sectional views of the structure of a non-linear two-terminal element used in a conventional matrix type display device, Figure 3 (bl and figure 4 (bl is a conventional matrix type display substrate) 1. Substrate, 2. Lower conductor layer, 3.
... Semiconductor layer, 4 ... Upper conductor layer, 11
... Electrode terminal, 12 ... Bus bar,
13... Lower conductor layer, 14... Lamination of semiconductor layer and upper conductor layer, 15... Picture element electrode, 1
01...Substrate, 102...Tantalum layer, 103...Tantalum oxide layer, 104...
...Picture element electrode, 105...Chromium layer, 106.
...Non-linear two-terminal element, 107...Bus bar, 108...Terminal, 109...
Picture element electrode, 201...Substrate, 202...
・First electrode, 203...N-type amorphous silicon,
204... Arch-shaped amorphous silicon, 205...
... P-type amorphous silicon, 206 ... chromium layer, 207 ... protective layer made of insulator, 208 ...
...Second electrode, 209...PIN diode, 210...Bus bar, 211...
...Picture element electrode. Name of agent: Patent attorney Toshio Nakao Hakaichi Meijyo
- Cze deaf＼Heri Kōyōjo 9 Figure 3 Figure 4? 10 0q (b)? ///

Claims (4)

[Claims] (1) On the substrate, a lower conductor layer having a gap in order, arsenic (As) and selenium (Se) placed on the gap and on the conductor layer.
), and an element having a structure in which an upper conductor layer is laminated on the semiconductor layer. (2) The matrix type display device according to claim (1), wherein the arsenic content of the arsenic and selenium compound constituting the semiconductor layer is 10 atomic % or more and 80 atomic % or less. (3) The lower conductor layer is indium oxide (In_2O_3) containing tin (Sn), tin oxide (SnO_2) containing antimony (Sb), chromium (Cr), aluminum (
The matrix type display device according to claim 1, characterized in that the display device is made of either Al) or titanium (Ti). (4) The upper conductor layer is made of tellurium (Te) and chromium (Cr).
, titanium (Ti), or aluminum (Al).