JPH0670695B2 - Matrix type display device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matrix type display device capable of high-display quality and large-capacity display. More specifically, it relates to a matrix type display device using a non-linear element.

2. Description of the Related Art Conventionally, in the matrix type display device using the proposed nonlinear element, the display medium is most often liquid crystal. Therefore, the matrix type liquid crystal display device will be described below as an example.

Liquid crystal display devices are expanding their fields of application from displays such as watches and calculators to terminal displays and video displays, and what is needed there is the ability to realize high-quality, large-capacity displays. The methods are (1) simple matrix method and
(2) There is an active matrix method, and (2) is
There are (2a) a method using a three-terminal element such as a thin film transistor (TFT) and (2b) a method using a non-linear two-terminal element. Each method has merits and demerits, (1) has a difficulty in display quality, and (2a) has a drawback that the manufacturing process is complicated and the cost is high. (2b) can be manufactured by an easier process than (2a), and the cost can be reduced.

There are three types of matrix type liquid crystal display devices with nonlinear elements.

First, the first one is an apparatus using an element as shown in FIG. [For example, Eye Triple E, Transaction, Electron, Devices, Edy Volume 28, No. 6, 7
Page 36 (1981) (IEEETRANSATION ON ELECTRON DEVIC
ES Vol. ED-28, No. 6,736 (1981)]. FIG. 3 (a) is a sectional view of the configuration of the non-linear two-terminal element, and FIG. 3 (b) is a layout view of a liquid crystal display substrate using the same. In the figure (a), 101 is a substrate, 102 is a tantalum (Ta) layer,
103 is tantalum oxide (Ta ₂ O ₅ ) obtained by anodic oxidation with a thickness of about 400 to 700 Å, 104 is a display electrode or a pixel electrode,
Reference numeral 105 is a connection wiring for connecting tantalum oxide (Ta ₂ O ₅ ) which is a cause of the non-linear characteristic and the display electrode and is made of a chromium (Cr) layer. In FIG. 107 is a lead wire or bus bar, 108 is a terminal, 10
Reference numeral 9 is a display electrode or a pixel electrode.

The second one is a device using an element as shown in FIG. [For example, the Technical Report of the Television Society, announced on May 25, 1984]. This is a structure in which two amorphous silicon (a-Si) PIN diodes are connected in parallel in the reverse direction in a ring shape to realize a non-linear element. Fourth
FIG. 3A is a sectional view of the structure of this element, and FIG.
FIG. 3 is a layout view of a liquid crystal display substrate using this element. In this figure, the PIN diode is indicated by a symbol representing a normal PN diode. In FIG. 4, 201 is a substrate, 2
02 is the first electrode, 203 is N-type a-Si, 204 is I-type a-Si, 20
5 is P-type a-Si, 206 is a chromium (Cr) 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, 210 is a bus bar, and 211 is a display. Electrodes or picture element electrodes.

The third is an apparatus using the device as shown in Fig. 5 [eg Proceedings of the Six International Discplay Research Conference, p. 72 (Proc.6TH Int.Display Resear
ch Conf., pp72]. FIG. 5 (a) is a sectional view of the configuration of this type of non-linear two-terminal element, and FIG. 5 (b) is a layout view of a liquid crystal display substrate using the same. In the figure (a), 301 is a substrate, 302 is a lead wire made of a transparent conductor layer, etc., and 303 is a non-linear structure made of a compound of silicon (Si), nitrogen (N) and hydrogen (H) with a thickness of about 1000Å. A layer, 304 is a display electrode or a pixel electrode, 305 is a connection wiring for connecting the non-linear layer and the display electrode and is made of a chromium (Cr) layer, and in the figure (b), 306 is a non-linear two-terminal element, Reference numeral 307 is a lead wire or a bus bar, 308 is a terminal, and 309 is a display electrode or a pixel electrode.

By using these non-linear resistance elements, it is possible to realize a display capacitance that is significantly larger than that of a normal liquid crystal display. If expressed by the duty ratio, it is possible to display a sufficiently high contrast even when driving with a duty ratio of about 1/1000.

Problems to be Solved by the Invention 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. It must be designed less than 1/10 of that of the part. However, regarding the first non-linear element according to the above-mentioned conventional technique, the tantalum oxide has a large relative permittivity of 20 or more, so that the element has a fine shape, which significantly deteriorates the yield. It is the cause.

Next, the first, second, and third examples of non-linear elements
In the case of (1), a vacuum process such as vapor deposition or sputtering is required to form a layer from which nonlinear characteristics are derived. This lowers the production yield and increases the production cost.

Therefore, an element that can be manufactured by a simple process, is stable, and has sufficiently large non-linear current-voltage characteristics is expected.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a plurality of lead wirings and a plurality of lead wirings on at least one substrate constituting a display device. A display electrode provided, at least an organic material layer interposed between the lead wiring and each of the display electrodes, and electrically cascaded, and the organic material layer in the main chain or side chain At least one of the group consisting of anthracene, pyrene, phenanthrene, coronene, indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline, thiadiazole, triazole, and hydrazone compound, and a film-forming resin. And a matrix type display device formed by

Function The present invention realizes a non-linear current-voltage characteristic by means of the above-mentioned organic material layer and means for making an electrical connection thereto, that is, a non-linear element portion having a conductor layer-organic material layer-conductor layer structure. ing. Current real elements - Measurement of the voltage characteristic shows a characteristic that can be approximated in the form of I = A * V ^α. Here, A and α are constants. By interposing this element between the lead wiring and the display electrode, the ratio of the on-voltage and the off-voltage applied to the picture element portion can be increased and the contrast characteristic can be improved.

The material of the conductor layer is titanium (Ti), aluminum (A1), chromium (Cr), gold (Au), nickel (N).
i), silicon (Si), germanium (Ge), tin (Sn), tungsten (W), molybdenum (Mo), tantalum (T
a), tin (Sn) added indium oxide transparent electrode (ITO
Electrodes), a tin oxide transparent electrode to which antimony (Sb) is added, and the like are desirable because of stable properties and easy thinning.

The material forming the organic material layer varies depending on the type, but the relative permittivity of this type of material is relatively small, 20 or less. Therefore, the shape of the nonlinear element according to the present invention can be made relatively large. This can be expected to improve the manufacturing yield.

The organic material layer can be easily obtained by a coating method. Microfabrication of this layer is possible by irradiation with an oxygen (O ₂ ) ion shower or ultraviolet irradiation in air for a long time.

Embodiment An embodiment of the matrix type display device of the present invention will be described below with reference to the drawings.

As described above, the liquid crystal is most practically used as the display medium in the matrix type display device using the non-linear element. Therefore, in the following description, the liquid crystal display device will be mainly described.

As described above, one of the conductors connected to the organic material layer is a lead wiring, or a part thereof branched from the lead wiring, and the other conductor is a part of the display electrode or a connection to the display electrode. This is the target connection wiring. It was confirmed that the effect of the present invention is exhibited in any case,
In the present embodiment, one of the conductors is used as a lead wire in the following.
The case where the other conductor is a connection wiring will be described.

FIG. 1A is a sectional view of the configuration of the nonlinear two-terminal element according to this embodiment, and FIG. 1B is a plan view. In the figure,
Reference numeral 1 is a substrate, 2 is a lower conductor layer, that is, lead wiring, 3 is an organic material layer, 4 is an upper conductor layer, that is, connection wiring, and 5 is a display electrode, that is, a pixel electrode. FIG. 2 is a layout view of the matrix type display device substrate according to the present embodiment.
Is a lead wire, 12 is a non-linear two-terminal element, 13 is a display electrode,
That is, it is a pixel electrode.

In the following examples, the lead wirings 2 to 11 are the indium oxide transparent electrodes (ITO electrodes) to which tin (Sn) is added.
Therefore, the pixel electrode 13 was formed of a transparent indium oxide electrode (ITO electrode) to which tin (Sn) was added. In particular, when the attenuation of the voltage due to the electrode resistance becomes a problem, the lead wires 2 to 11 are made of a material having high conductivity, such as aluminum (A1).

Further, the organic material layer has a main chain or side chain of anthracene, pyrene, phenanthrene, polycyclic aromatic compound such as coronene or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole,
Oxadiazole, pyrazoline, thiadiazole, a compound having a nitrogen-containing cyclic compound such as triazole, at least one of the group consisting of hydrazone compounds, and a film-forming resin, was formed using a simple coating method,
Here, the case of a hydrazone compound will be described.

Obtain soda glass with ITO that has been etched into a predetermined pattern, immerse this substrate in fuming nitric acid, wash with water, and dry.

next, 8 parts of a hydrazone compound represented by the following structural formula, polysanphone resin (trade name: Udel P1700, Nissan Chemical Co., Ltd.)
12 parts) was dissolved in 500 parts of toluene to prepare a coating solution. The substrate was immersed in this solution, then naturally dried for 10 minutes, and further dried by heating at 100 ° C. for 1 hour. Then about 3
A mask made of 0 μm · meter magnetic stainless steel and having a predetermined pattern of holes is aligned with the substrate using an aligner, and a samarium / cobalt magnet is placed on the back surface of the substrate to form a metal mask and a substrate. Were brought into close contact with each other, and this was irradiated with ultraviolet rays in the air for 2 hours. Thus,
The unnecessary portion was decomposed with ozone (O ₃ ) or the like to obtain an organic material layer having a desired shape.

The connection wiring was formed by a vapor deposition method using a metal mask. Thus, a substrate as shown in FIG. 2 was obtained.

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

Furthermore, the substrate on which the nonlinear two-terminal element is formed and the strip-shaped
After forming an alignment film on each of the counter substrates having ITO formed on the surface, a rubbing treatment was performed, and the two substrates were bonded to each other to form a panel, and a liquid crystal was injected. The rubbing direction was such that the liquid crystal molecules had a 90 ° twist structure.

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

The non-linearity of the current-voltage characteristic of the device was as remarkable as α = 8 to 11. Further, its capacity was sufficiently smaller than that of the liquid crystal layer. Further, the non-linearity was not impaired by the light irradiation.

When a liquid crystal display panel was manufactured using this substrate, a display with a contrast of 10: 1 or more could be realized during matrix driving with a duty ratio of 1/1000 and a bias ratio of 1/7.

Further, although the liquid crystal is taken as an example of the display medium, the same effect can be obtained by using an electroluminescent device (EL), an electrophoretic device (EPID), an electrochromic device, a plasma light emitting device, or the like. Needless to say.

EFFECTS OF THE INVENTION As described above, the non-linear two-terminal element of the present invention has a simple structure, and therefore can be manufactured with a high yield, and further has excellent non-linearity with respect to current-voltage characteristics. Therefore, the matrix type display device using the element according to the present invention can display a large capacity and can realize good display quality.

[Brief description of drawings]

FIG. 1 is a sectional view (a) of a nonlinear two-terminal element used in a matrix type display device according to the present invention and a plan view (b), and FIG. 2 is a layout view of a substrate for a matrix type display device according to the present invention. FIGS. 3 (a), 4 (a) and 5 (a) are sectional views showing the configuration of a non-linear two-terminal element used in a conventional matrix type display device, FIGS. 3 (b) and 4 (). FIG. 5B and FIG. 5B are layout diagrams of the non-linear two-terminal element used in the matrix type display device in the conventional example. 1 ... substrate, 2 ... lower conductor layer, that is, lead wiring,
3 ... Organic material layer, 4 ... Upper conductor layer, that is, connection wiring, 5 ... Display electrode, that is, pixel electrode, 11 ... Lead wiring, 12 ... Non-linear two-terminal element, 13 ... Display electrode, that is, Pixel electrode, 101 ... Substrate, 102 ... Tantalum (Ta)
Layer, 103 ... Tantalum oxide (Ta ₂ O ₅ ) obtained by anodic oxidation with a thickness of about 400 to 700Å, 104 ... Display electrode or pixel electrode, 105 ... Tantalum oxide (Ta that causes non-linear characteristics) _{2 0 5} ) and the connection wiring that connects the display electrode, 106 …… Non-linear two-terminal element, 107 …… Lead wiring or bus bar, 108 …… Terminal, 109 …… Display electrode or pixel electrode, 20
1 ... Substrate, 202 ... First electrode, 203 ... N-type a-Si, 204
...... I-type a-Si, 205 ...... P-type a-Si, 206 …… Chromium (Cr) layer, 207 …… Protective layer made of an insulator, 208 …… Second
Electrode, 209 ... PIN diode connected in a ring, 210
...... Bus bar, 211 …… Display electrode or pixel electrode, 301
...... Substrate, 302 ...... Lead wiring consisting of transparent conductor layer, etc. 303 ・ ・ ・ Thickness about 1000Å Silicon (Si) and Nitrogen (N)
A non-linear layer formed of a compound of hydrogen and hydrogen (H), 304 ... Display electrode or pixel electrode, 305 ... Connection wiring connecting the non-linear layer and the display electrode, 306 ... Non-linear two-terminal element, 3
07-lead wiring or bus bar, 308-terminal, 309
...... Display electrode or pixel electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Ota 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Akira Minobe 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A plurality of lead wires, a plurality of display electrodes provided for each of the lead wires, and a space between the lead wires and each of the display electrodes on at least one substrate constituting a display device. And an organic substance layer which is electrically connected in series, and the organic substance layer has anthracene, pyrene, phenanthrene, coronene, indole, carbazole, oxazole, isoxazole, thiazole in the main chain or side chain. , Imidazole,
A matrix-type display device comprising at least one of the group consisting of a pyrazole, an oxadiazole, a pyrazoline, a thiadiazole, a triazole, and a hydrazone compound, and a film-forming resin.