JP3096372B2 - Two-terminal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type display device using two terminal elements.

[0002]

2. Description of the Related Art A liquid crystal display device is a typical display device replacing a CRT. A liquid crystal display device uses a liquid crystal as a display medium and applies a voltage to the liquid crystal layer to cause an electro-optical change in the liquid crystal, thereby displaying large-capacity characters and images. In this liquid crystal display device, a method using a two-terminal non-linear element or a three-terminal active element as a switching element has been actively studied and developed. The two-terminal element has a feature that the structure is simpler than the three-terminal element, so that the number of masks is small and the manufacturing process is simple.

A method using a two-terminal nonlinear element is roughly classified into a method using the nonlinearity of the capacitance of the two-terminal nonlinear element and a method using the nonlinearity of the electric resistance.

[0004] An attempt to display a liquid crystal using the non-linearity of the capacitance of a two-terminal non-linear element has been made by Gramair et al. For a liquid crystal element using a ferroelectric liquid crystal as a display medium.
l. Cryst. Liq. Cryst. 15 (197
1), and Tannas et al.
p. Digest (1973).

However, this method requires a large driving voltage, and the ferroelectric liquid crystal has a large temperature dependence of the dielectric constant.
Since the completed device also has a drawback that it has temperature dependency, it has not yet been put to practical use.

As a method of using the nonlinearity of the electric resistance of a two-terminal nonlinear element, Lechner has described in Proc. IE
EE59. (1971) proposed a method using a diode. Tran
s. Electron Devices ED-26
(1979) described a method using a ZnO varistor, and Baraff et al. Trans. Elect
ron DevicesED-28 (1981)
A method using IM (Metal Insulator Metal, metal-insulating layer-metal) has been proposed.

[0007] As a feature of MIM, Thin Fil
m Transistor (TFT)
Since the scanning lines and the signal lines are not disposed together on one substrate as in FT (abbreviated as FT), the ratio (opening ratio) of the pixel area in the screen can be made larger than that of the TFTs. There are few line defects caused by poor insulation at intersections with lines. In addition, the number of masks in the manufacturing process is small, and the manufacturing process is simple, so that the manufacturing yield is high. Since there is no generation of photoexcitation current which is a problem in TFTs and diodes using amorphous silicon, the MIM element is shielded from external light. It is unnecessary.

FIG. 7 shows an example of a basic structure of a display device having a conventional MIM. FIG. 7A shows one picture element portion of the matrix substrate. FIG. 7B shows a cross section of FIG.

A scanning line 12 is provided on a substrate 11.
2b is branched. This scanning line 12 and its electrode 1
An anodizing treatment is performed on the surface of 2b to form an insulating film 13 made of Ta ₂ O ₅ . A rectangular metal film piece 14 made of Ta or the like is formed so as to cover the anodized electrode 12b and cross the electrode 12b. A plurality of rectangular picture element electrodes 15 are formed so as to cover the electrodes 12b and the metal film pieces 14, respectively.

The three-layer structure of the electrode 12b, the insulating film 13 on the surface of the electrode 12b and the metal film piece 14 constitutes an MIM element. That is, the electrode 12b is the first metal of the MIM element,
The insulating film 13 on the surface of the electrode 12b corresponds to the insulating layer of the MIM element, and the metal film piece 14 corresponds to the second metal of the MIM element.

On the other hand, a plurality of opposing electrodes 16 are formed on the opposing substrate 17 at a width perpendicular to the scanning lines 12 of the pixel electrodes 15 on the base substrate 11 and at the same pitch as the arrangement pitch of the scanning lines 12. 16 ... are provided.

The counter substrate 17 and the base substrate 11
And the counter electrodes 16 are connected to the adjacent scanning lines 12, 1, 1 on the base substrate 11.
The two substrates 11 and 17 are adhered so as to run in parallel between the two, and after injecting a liquid crystal 18 as a display medium, sealing is performed to obtain a display panel.

[0013]

By the way, the two-terminal element is strongly required to have the following element characteristics.

That is, the voltage V applied to the insulating layer between the first metal and the second metal of the two-terminal element and the rise of the current I flowing between the two metals in response to the application of the voltage V are steep. In addition, it is required to have an IV characteristic that the symmetry of the current value is independent of the polarity of the applied voltage V, and that the symmetry of the IV characteristic be uniform for each pixel. I have.

FIG. 8 shows an IV characteristic curve of the conventional MIM element. As shown in this figure, the conventional MIM element has not obtained the symmetry of the IV characteristic. This is because the first metal of the MIM element is in contact with the insulating layer formed by anodic oxidation, while the second metal is formed on the insulating layer by sputtering or CVD. It is considered that the state of the interface between the first metal and the first metal and the state of the interface between the insulating layer and the second metal are different. It is also considered that an impurity penetrates into the insulating layer during the anodic oxidation of the first metal, and the impurity concentration is different between the vicinity of the interface of the first metal and the vicinity of the interface of the second metal.

As described above, the state of the interface between the insulating layer and the first metal and the state of the interface between the insulating layer and the second metal depend on the IIM of the MIM element.
The type of metal used in the MIM element is limited because it affects the -V characteristic. For example, in the case of a conventional MIM element using Ta ₂ O ₅ for the insulating layer, Cr, Ta, and Ti are used for the second metal, and when Al or ITO is used, the symmetry of the IV characteristic is obtained. Becomes significantly worse.

The IV characteristic of the MIM element is Pool-
The following formula is represented by the Frenkel current.

I = α · V · exp (β√V) ··· α = (nμq / d) · exp (-ψ / (kT)) ··· β = (1 / (kT)) √ (Q ³ / (πεd)) where q: charge n: carrier density
μ: mobility ψ: trap depth d: film thickness of insulating layer T: temperature ε: dielectric constant k: Boltzmann constant The β value shown by the equation indicates the steepness of the IV characteristics of this MIM element. The larger the value, the better the IV characteristics. For example, in the case of a MIM element using Ta ₂ O ₅ for the insulating layer, about 3
However, since the β value of the varistor, which is a kind of two-terminal element, is about 7 to 8, the MI using Ta ₂ O ₅ for the insulating layer is preferable.
In the case of the M element, the IV characteristics are inferior to this varistor.

However, when a semiconductor layer is used instead of an insulating layer such as Ta ₂ O _5, it is possible to form a two-terminal active element having a sharp IV characteristic. FIG. 9 shows a cross section of an example of a two-terminal element having a semiconductor layer. Examples of the semiconductor layer include zinc sulfide (ZnS), zinc selenide (ZnSe), and zinc oxide (ZnO).
A two-terminal element using S) for a semiconductor layer will be described.

A scanning line 22 which is a first metal of a two-terminal element is formed on a base substrate 21, and a ZnS semiconductor layer 24 is formed so as to cover the scanning line 22. Further, a picture element electrode 25 serving also as a second metal of the two-terminal element is superimposed on a part of the semiconductor layer 24.

FIG. 10 shows the IV characteristics of this two-terminal device. FIG. 10A shows the IV characteristics when the two-terminal element is not irradiated with light, and FIG. 10B shows the IV characteristics when the light is irradiated.
-V characteristics are shown. As can be understood from this figure, the IV characteristics of this device structure are steep and symmetric in both cases (a) and (b). Is steeper than when irradiating. This is for the following reasons.

There are two types of ZnS crystal structures, a zinc blende type structure and a wurtzite type structure. The bandgap of the zinc-blende structure is 3.4 eV, and the bandgap of the wurtzite structure is 3.7 eV, which is a wide wavelength band in the visible region (400 nm).
m-700 nm), the ZnS thin film is transparent.
However, a ZnS thin film formed by a sputtering method, a vacuum evaporation method, or the like has a polycrystalline structure with many crystal defects. In some cases, manganese (Mn) or a fluorinated compound is mixed with ZnS to stabilize the ZnS thin film. In this case, impurities such as manganese replace Zn. For this reason, it is considered that crystal defects and impurities generate a level between the band gaps to generate photoconduction, thereby causing a change in the IV characteristics of the two-terminal element.

For this reason, a technique has been proposed to solve this problem by providing a light shielding layer in an active element that generates photoconduction. For example, in the case of a TFT element, Japanese Patent Application Laid-Open No. 55-77782 discloses 2
The case of a terminal element is described in JP-A-4-221930. However, the technology of providing the light-shielding layer described in these documents is to provide the light-shielding layer and the element separately, and the number of steps for providing the light-shielding layer increases, resulting in an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In a display device having a two-terminal element having a semiconductor layer, the abruptness of the IV characteristic of the two-terminal element is improved. An object is to simplify the forming process while maintaining stability.

[0025]

According to the present invention, there is provided a two-terminal display device comprising: a plurality of scanning lines arranged in parallel on a substrate;
A plurality of first electrodes branched from the respective scanning lines; an insulating film formed on the substrate covering the respective scanning lines and the respective first electrodes; and an insulating film formed on the insulating film and intersecting with the respective first electrodes. And is covered by each first electrode when viewed from each first electrode side.
A semiconductor layer formed in a region smaller than each first electrode so as to cover each semiconductor layer so as to cover each semiconductor layer with an area larger than a plane region of each semiconductor layer. An electrode, a picture element electrode electrically connected to each of the second electrodes, a counter substrate disposed to face the substrate, and a display having electro-optical characteristics sealed between the substrate and the counter substrate. A medium and a counter electrode formed on the inner surface of the counter substrate for applying a voltage to the display medium between the pixel electrodes on the substrate to cause optical modulation. The film is a two-terminal display device that electrically insulates the first electrode and the second electrode, thereby achieving the above object.

Further, the two-terminal display device of the present invention comprises a plurality of scanning lines arranged in parallel on the substrate, a plurality of first electrodes branched from each scanning line, and a plurality of first electrodes intersecting each first electrode. hand,
And covered by each first electrode when viewed from each first electrode side.
A semiconductor layer formed in a region smaller than each first electrode so as to be hidden, an insulating film formed on the substrate so as to cover each scanning line and each semiconductor layer, and A second electrode formed on the semiconductor layer so as to cover each semiconductor layer so as to cover the semiconductor layer with an area larger than a plane area of the semiconductor layer, a picture element electrode electrically connected to each second electrode, A counter substrate disposed to face the substrate, a display medium having electro-optical characteristics sealed between the substrate and the counter substrate,
A counter electrode formed on the inner surface of the counter substrate so as to apply a voltage to the display medium between the pixel electrodes on the substrate to cause optical modulation, and an insulating film, A two-terminal display device for electrically insulating the first electrode and the second electrode, thereby achieving the above object.

Further, the two-terminal display device of the present invention comprises a plurality of scanning lines arranged in parallel with each other on a substrate, a plurality of first electrodes branched from each scanning line, each scanning line and each first line. A first insulating film that covers the electrodes and is formed on the substrate, and a first insulating film on the first insulating film that intersects each first electrode and that is viewed from each first electrode side; Covered by the first electrode
A semiconductor layer formed in a region smaller than each first electrode so as to cover each scanning line and each semiconductor layer, and a second insulating film formed on the first insulating film so as to cover each scanning line and each semiconductor layer. On the insulating film of the above, with an area larger than the plane region of each semiconductor layer,
A second electrode formed so as to intersect each semiconductor layer so as to cover each semiconductor layer, a pixel electrode electrically connected to each second electrode, and a counter substrate disposed to face the substrate. A voltage is applied to the display medium between the display medium having electro-optical characteristics encapsulated between the substrate and the counter substrate and each pixel electrode on the substrate to cause optical modulation. And a counter electrode formed on an inner surface of the counter substrate, thereby achieving the object described above.

Preferably, the semiconductor layer is formed of a Zn compound.

[0029]

A two-terminal element is formed between a first electrode and a second electrode with a semiconductor layer and an insulating film sandwiched in a direction perpendicular to the substrate. In addition, since the planar region of the semiconductor layer is formed with a smaller area than the first electrode and the second electrode, both electrodes also function as a light shielding layer for the semiconductor layer.

[0030]

Embodiments of the present invention will be described below.

(Embodiment 1) FIG. 1A shows one picture element portion of a substrate having a two-terminal element according to Embodiment 1 of the present invention. FIG. 1B shows a cross section taken along line AA ′ in FIG.

The scanning line 2a and the first branching in a direction perpendicular to the scanning line 2a on the insulating base substrate 1 such as glass.
An electrode 2b is formed. The scanning line 2a and the first
An insulating film 3 is formed over the entire surface of the substrate so as to cover the electrode 2b. A semiconductor layer 4 is formed in contact with the insulating film 3 and crossing the first electrode 2b.

Each of the first electrodes 2b extends along the scanning line 2a.
A pixel electrode 5 having a rectangular shape is formed on the insulating film 3 in correspondence with the above. Each pixel electrode 5 has one overhang 6, and each overhang 6 is formed on the insulating film 3 so as to cover the semiconductor layer 4 on the corresponding first electrode 2 b. I have. A portion in which the terminal portion of the first electrode 2b, the insulating film 3, the semiconductor layer 4, and the overhanging portion 6 of the picture element electrode 5 are vertically stacked constitutes a two-terminal element. That is, the overhang portion 6 is the second electrode of the two-terminal element according to the first embodiment. (Hereinafter, the overhanging portion 6 is referred to as a second electrode 6) Further, the pixel electrode 5 and the second electrode 6
And an alignment film 7 is formed over the entire surface of the base substrate 1.

The opposing substrate 9 disposed opposite to the base substrate 1 is made of an insulating substrate such as glass, and the inner surface of the opposing substrate 9 is formed on the inner surface of the base substrate 1 in a direction parallel to the scanning lines 2a.
And a plurality of counter electrodes 8, 8 ... each having a width covering each pixel electrode 5 is formed corresponding to the arrangement of the picture element electrode 5. An alignment film 7 is formed over the entire inner surface of the counter substrate 9 so as to cover the counter electrode 8 . The liquid crystal 10 is interposed between the base substrate 1 and the counter substrate 9 as described above.

Such a liquid crystal display device is manufactured as follows. First, an insulating base substrate 1 such as glass
A conductive thin film is formed thereon by a sputtering method.
The material of the thin film may be a conductive material that does not transmit light, and examples thereof include Ta, Al, Ti, and Nb. In Example 1, Ta was used. In addition, for thin film formation, C
It is also possible to use a forming method such as a VD method and an evaporation method.

Subsequently, the conductive thin film is patterned into a predetermined shape to obtain a scanning line 2a and a first electrode 2b branched from the scanning line 2a. The scanning line 2a and the first electrode 2b
And an insulating film 3 is formed on the entire surface of the base substrate 1 by a sputtering method. In the first embodiment, the insulating film 3 is
Although Ta ₂ O ₅ was used, any material may be used as long as it electrically insulates the first electrode 2 b and the second electrode 6. In addition, for example, oxides such as silicon oxide, aluminum oxide, and titanium oxide, or aluminum nitride And nitrides such as silicon nitride.

Next, on the insulating film 3, the first electrode 2b
And the semiconductor layer 4 is laminated with a predetermined thickness. In Example 1, zinc sulfide (ZnS) was used for the semiconductor layer 4. As a method for forming the ZnS film, a sputtering method, C
There are thin film forming methods such as a VD method and a vapor deposition method. In the first embodiment, a sputtering method is used.

As a target of the sputtering method,
Using a high purity ZnS powder spread on quartz glass, this target is set in an RF sputtering apparatus.

Although an element can be formed only with a ZnS film, manganese (M) is used to stabilize the electrical characteristics of the element.
Trace elements such as n) can also be injected into the ZnS film. In the first embodiment, manganese (Mn) is injected into the ZnS film.
A powder mixed with 0.5 wt% based on the weight of S was used.

Other substances that can be added to the ZnS film for the same purpose include rare earth elements such as copper (Cu), terbium (Tb), samarium (Sm), and europium (Eu), and oxidation of these rare earth elements. Thing, hooker thing, carbonate,
There are phosphate, oxalate, chloride, bromide, iodide, nitrate and the like.

An Ar gas was used as a sputtering gas, and the sputtering conditions were as follows.

Substrate temperature 250 ° C. Gas pressure 10 Pa Input power 750 W Next, the ZnS film of the semiconductor layer 4 is patterned in a rectangular shape on the first electrode 2 b. At this time, the width of the rectangular first electrode 2b in the width direction is smaller than the width of the first electrode 2b so that the semiconductor layer 4 does not protrude from the first electrode 2b.

Further, a thin film of Al is formed on the entire surface of the substrate on the insulating film 3 covering the semiconductor layer 4 by a sputtering method, and the second electrode 6 is formed by patterning. There are other methods for forming a thin film, such as a CVD method and a vapor deposition method.

The second electrode 6 is patterned so as to cover the ZnS film. The material of the second electrode 6 may be any conductive material that does not transmit light.
Was used, but Ta, Ti, Nb or the like can be used. In this manner, the area of the planar region of the semiconductor layer 4 is
By making the area of the electrode 2b and the area of the second electrode 6 smaller than each other, the semiconductor layer 4 is not irradiated with light and no photoconduction occurs, so that the electrical characteristics of the element can be stabilized.

Subsequently, an ITO film is laminated on the entire surface of the substrate so as to cover these elements, and is patterned to form the pixel electrodes 5. The pixel electrode 5 is provided with an overhanging portion, and patterning is performed so that the overhanging portion intersects the second electrode 6. This is a case of manufacturing a transmission type display device,
In the case of a reflection type display device, since a non-transmissive light type material is used for the pixel electrode 5, it can be formed simultaneously with the second electrode 6 using the same material.

Finally, an alignment film 7 is formed on the entire surface of the base substrate 1 covering all of the above elements. After curing, the alignment film 7 is subjected to an alignment process.

On the other hand, as the opposing substrate 9, a transparent conductive ITO film is formed on the surface of an insulating substrate such as glass.
This ITO film is patterned to form a plurality of opposing electrodes 8, 8.
... is formed. The counter electrode 8 is formed in a line shape having a width covering each pixel electrode 5 on the base substrate 1 in parallel with each other. An alignment film 7 is formed on the entire surface of the counter substrate 9 so as to cover the counter electrodes 8, 8,..., And after the alignment film 7 is cured, an alignment process is performed.

The two substrates 1 and 9 of the base substrate 1 and the opposing substrate 9 are placed such that the surface on which the pixel electrodes 5 are formed on the base substrate 1 and the surface on which the opposing electrodes 8 are formed on the opposing substrate 9 face each other.
In addition, the scanning lines 2a and the opposing electrodes 8 are bonded so as to be parallel to each other. Finally, the liquid crystal 1 is placed between the substrates 1 and 9.
0 is injected and sealed to obtain a liquid crystal display device.

Such a liquid crystal display device operates as follows. FIG. 3 shows an equivalent circuit corresponding to one pixel of a liquid crystal display device having two terminal elements. 2 have respective terminal element and the liquid crystal layer capacitor, connected in series between the capacitor C _D and the capacitance C _L of the liquid crystal layer of the two-terminal element and the first electrode 2 and the counter electrode 7 of the two-terminal element Form an equivalent circuit.

[0050] When both ends of a voltage V of the first electrode 2 and the counter electrode 8 is applied, the voltage V _D applied to the two-terminal device the voltage V becomes as volume divided by the following equation.

[0051] _{V D = V · C L /} (C L + C D) ··· In addition, the voltage V _L applied to the liquid crystal capacity C _L is expressed by the following equation.

V _L = V · C _D / (C _L + C _D ) From the formula, when C _L >> C _D , the value of V _D approaches V and a sufficient voltage is applied to the two-terminal element. . The voltage V _D applied to the two-terminal element is a threshold voltage V _TH unique to the two-terminal element.
Is exceeded, the two-terminal element becomes conductive. At this time, the liquid crystal capacitance _CL is charged by the voltage _VL shown in the equation, and the electric charge is accumulated.

Meanwhile, when the voltage V _D applied to the two-terminal device is smaller than its second terminal device-specific threshold value voltage V _{T H} 2-terminal element is turned off. Even when the two-terminal element is turned off, the charge accumulated in the on state drives the liquid crystal.

The two-terminal element I- of the first embodiment
FIG. 4 shows the V characteristic curve. As can be seen from the figure, the rise of the current is sharp and the symmetry is good.

In the first embodiment, the insulating film 3 is formed between the first electrode 2 b and the semiconductor layer 4. However, the structure in which the insulating film 3 is formed between the semiconductor layer 4 and the second electrode 6. However, it shows the same operation as above. FIG. 2 shows this element structure.

As described above, by setting the plane area of the semiconductor layer 4 of the two-terminal element to be smaller than the area of the first electrode 2b and the area of the second electrode 6, the semiconductor layer 4 is not irradiated with light.
Since no photoconduction occurs, the electrical characteristics of the element are stabilized.

(Embodiment 2) FIG. 5 shows one pixel portion of a liquid crystal display device according to Embodiment 2 of the present invention. FIG. 5A shows the plan configuration, and FIG. 5B shows the cross-sectional configuration. The plan configuration is the same as that of the first embodiment, and thus the description is omitted. In the cross-sectional configuration, the same elements as those in the first embodiment will be described with the same reference numerals.

The structure of the base substrate 1 of the first embodiment is such that the second electrode 6 is formed on the semiconductor layer 4.
In the second embodiment, the semiconductor layer 4 is formed by the first insulating film 3a.
And a second insulating film 3b, and a second electrode 6 is formed on the second insulating film 3b so as to cover the semiconductor layer 4. The pixel electrode 5 formed on the insulating film 3 in the first embodiment (corresponding to the first insulating film 3a in the second embodiment) is formed on the second insulating film 3b in the second embodiment. Is done.

In manufacturing the substrate according to the second embodiment,
The steps up to the formation of the semiconductor layer 4 are the same as in the first embodiment. In the second embodiment, after the formation of the semiconductor layer 4, first, a second insulating film 3b is laminated on the first insulating film 3a so as to cover the semiconductor layer 4. Hereinafter, a method of forming the second insulating film 3b in contact with the ZnS film of the semiconductor layer 4 will be described.

Using a silicon target as a sputtering target, sputtering was performed in an Ar gas atmosphere under the following conditions.

Substrate temperature 250 ° C. Gas pressure 8 Pa Input power 750 W When the second insulating film 3 b is formed using SiN _X , subsequently, the pixel electrode 5 is formed on the second insulating film 3 b,
Thereafter, a display device was manufactured by the same process as in Example 1.

The second method of driving the two-terminal device according to the second embodiment in which the second insulating film 3b is formed so as to cover the ZnS film of the semiconductor layer 4 and the second electrode 6 is formed on the second insulating film 3b is non-linear in the capacitance of the two-terminal device. FIG. 6 shows the QV characteristics of the two-terminal device according to the second embodiment. As shown in this figure, it can be understood that the QV characteristics according to the second embodiment are also steep, and in particular, the symmetry is good. The type of both insulating films 3a and 3b is not particularly limited, but in order to further improve the symmetry of the QV characteristic, the types of the insulating films 3a and 3b in contact with both sides of the ZnS film of the semiconductor layer 4 are the same. More preferably,

Also in the second embodiment, by setting the planar area of the semiconductor layer 4 of the two-terminal element to be smaller than the area of the first electrode 2b and the area of the second electrode 6, the semiconductor layer 4 is not irradiated with light, Since no conduction occurs, the electrical characteristics of the element are stabilized.

[0064]

As described above, according to the present invention, a two-terminal element having a structure in which a semiconductor layer and an insulating film are interposed between a first electrode and a second electrode is used. IV characteristics are steeper and better in symmetry than a two-terminal element having a structure in which an insulating layer is interposed between the two terminals. In addition, since the planar region of the semiconductor layer is smaller in area than the first electrode and the second electrode, and the semiconductor layer is covered with both electrodes and is not irradiated with light, photoconduction does not occur. Therefore, the electrical characteristics of the element are stabilized, and the reliability of the display characteristics can be improved.

Further, since both electrodes function as a light-shielding layer and there is no need to separately provide the electrode and the light-shielding layer, the device can be manufactured easily and with a high yield. Therefore, a low-cost two-terminal display device can be stably provided.

[Brief description of the drawings]

FIG. 1 is a picture element section of a liquid crystal display device according to a first embodiment of the present invention. (A) is a plan view, (b) is a cross-sectional view taken along line AA 'of (a).

FIG. 2 is a diagram showing a pixel portion of a liquid crystal display device according to a modification of the first embodiment of the present invention. (A) is a plan view, (b) is a line B in (a)
Sectional drawing by -B '.

FIG. 3 is an equivalent circuit of one pixel of the two-terminal display device according to the present invention.

FIG. 4 is an IV characteristic diagram of the two-terminal element according to the present invention.

FIG. 5 is a picture element section of a liquid crystal display device according to a second embodiment of the present invention. (A) is a plan view, (b) is a cross-sectional view taken along line CC ′ of (a).

FIG. 6 is a graph showing QV of a two-terminal element according to a second embodiment of the present invention.
Characteristic diagram.

FIG. 7 is a picture element section of a conventional two-terminal liquid crystal display device.
(A) is a plan view, (b) is a cross-sectional view taken along line DD ′ of (a).

FIG. 8 is an IV characteristic diagram of a conventional two-terminal display element.

FIG. 9 is a cross-sectional view of a two-terminal element having a semiconductor layer.

FIG. 10 is an IV characteristic diagram of a two-terminal element having a semiconductor layer. (A) is an IV characteristic diagram when the element is irradiated with light.
(B) is an IV characteristic diagram when the element is not irradiated with light.

[Description of Signs] 1 Base substrate 2a Scan line 2b First electrode 3 Insulating film 3a First insulating film 3b Second insulating film 4 Semiconductor layer (ZnS film) 5 Pixel electrode 6 Second electrode (Picture electrode extension) 7) Alignment film 8 Counter electrode 9 Counter substrate 10 Liquid crystal (liquid crystal layer)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1362 G02F 1/13 101 H01L 49/02

Claims (3)

(57) [Claims] A plurality of scanning lines disposed in parallel with each other on a substrate, a plurality of first electrodes branched from the respective scanning lines, and a plurality of scanning lines and the first electrodes. The formed insulating film, and on the insulating film, intersecting with each of the first electrodes and being covered by each of the first electrodes when viewed from each of the first electrodes.
A semiconductor layer formed in a region smaller than each first electrode as described above, and a second formed crossing each semiconductor layer so as to cover each semiconductor layer with an area larger than the plane region of each semiconductor layer.
An electrode; a pixel electrode electrically connected to each second electrode; a counter substrate disposed to face the substrate; and a display having electro-optical characteristics sealed between the substrate and the counter substrate. A medium, and a counter electrode formed on the inner surface of the counter substrate for applying a voltage to the display medium between the pixel electrodes on the substrate to cause optical modulation. A two-terminal display device, wherein the film electrically insulates the first electrode and the second electrode. 2. A plurality of scanning lines arranged in parallel with each other on a substrate, a plurality of first electrodes branched from each scanning line, and a plurality of first electrodes intersecting each other and extending from each first electrode side. When you see
A semiconductor layer formed in a region smaller than each first electrode so as to be covered by each first electrode ; an insulating film formed on the substrate so as to cover each scanning line and each semiconductor layer; A second electrode formed above and crossing each semiconductor layer so as to cover each semiconductor layer with an area larger than the plane area of each semiconductor layer; and a second electrode electrically connected to each second electrode. A pixel electrode, a counter substrate disposed opposite to the substrate, a display medium having electro-optical characteristics sealed between the substrate and the counter substrate, and each pixel electrode on the substrate. A counter electrode formed on the inner surface of the counter substrate to apply optical voltage by applying a voltage to the display medium between the first electrode and the second electrode; Two-terminal display device that electrically insulates the display. 3. A plurality of scanning lines arranged in parallel with each other on a substrate, a plurality of first electrodes branched from each scanning line, and a plurality of scanning lines and each first electrode. A first insulating film formed on the first insulating film, the first insulating film intersects with each first electrode, and is covered by each first electrode when viewed from each first electrode side;
A second insulating film formed on the first insulating film so as to cover each scan line and each semiconductor layer; A second electrode formed on the insulating film and having a larger area than the plane area of each semiconductor layer and intersecting each semiconductor layer so as to cover each semiconductor layer; A pixel electrode, which is electrically connected to the substrate, a counter substrate disposed to face the substrate, a display medium having electro-optical characteristics encapsulated between the substrate and the counter substrate, and each picture on the substrate. A two-terminal display device comprising: a counter electrode formed on an inner surface of the counter substrate so that a voltage is applied to the display medium between the counter substrate and the display medium to cause optical modulation.