JPS63187280A - Matrix display device - 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] Industrial Application Field The present invention is a matrix consisting of a low-cost non-linear two-terminal element with a simple configuration and having high display quality such as high contrast, which is effective for use in video equipment, information equipment, etc. This invention relates to display devices.

2. Description of the Related Art In recent years, matrix display devices, particularly liquid crystal display devices, have been actively approached for large-capacity displays, especially image displays, in the information equipment field centered on computers and the video equipment field. It is attracting attention as a display that can realize affordable devices. A nonlinear two-terminal element is a two-terminal element that exhibits nonlinear current-voltage characteristics and exhibits constant voltage characteristics proximally in a relatively large voltage region. An example of a liquid crystal display device using a conventionally proposed non-linear two-terminal element will be described below with reference to the drawings.

Figure 2 (a) shows a non-linear two-terminal element (M T M element: M
FIG. 2 is an example of a cross-sectional view of the vicinity of a picture element on one side of the substrate of a liquid crystal display panel in which each picture element is provided with a metal-insulator-metal element (metal-insulator-metal element) for each picture element. A non-linear two-terminal element 46 is formed from the layer 42, an anodized tank layer 43, a pixel electrode layer 44, and a chromium layer 45. Terminal array. [For example, iTriple E, Transaction, ON, Electron, Devices, E.D. 2
Volume 8-No. 6-1981 (IEEE TRANSACTI
ONON ELECTORON DEVICES, V
OL, ED-28, NO, 6, 1981).

Society of Information Display (SID; 5ociety Fo
198 of r Information Display)
4th year international symposium technical papers (SID Inter)
National Symposium Digest
Of Tech-nical Papers) P2
O3-305) Figure 3 is an example of PIN diodes connected in a ring shape to form a non-linear two-terminal element.
al is a cross-sectional view of the configuration of a PIN diode, and FIG. 3(b) is a layout diagram of one side of the substrate of a liquid crystal display panel using this PIN diode. In FIG. 3 (bl), the PIN diode is shown with the usual PN diode symbol. On the substrate 51 are a first electrode layer 52, an N-type amorphous silicon 53,
Type amorphous silicon 54, N type amorphous silicon 55, chromium layer 56
, a protective layer 57 made of an insulator, a second electrode layer 58, and a PIN diode 59 connected in a ring shape.
A bus bar 60 and a picture element electrode 61 form a nonlinear two-terminal array. [For example, the Technical Report of the Television Society of Japan, published on May 25, 1980] In a normal liquid crystal display panel, the duty ratio is limited to about 1/200, but by using these nonlinear resistance elements, the duty ratio can be increased. 1
/1000 high quality liquid crystal display characteristics can be obtained.

FIG. 4 is an equivalent circuit diagram of a liquid crystal display panel using nonlinear two-terminal elements. In order for this panel to work properly,
The current needs to flow mainly through the path of the nonlinear resistor 70 and the capacitor 73 of the liquid crystal layer. In order for the non-linear two-terminal element to function properly, the non-linear resistance parallel capacitance 71 must be made small. Note that 72 is the resistance of the liquid crystal layer, 74 is a non-linear resistance element, and 75 is the liquid crystal layer.

FIG. 5 is a diagram showing the structure of a matrix display panel using nonlinear two-terminal elements. An alignment film 83 is formed on the surfaces of the substrate 80 having strip-shaped electrodes and the non-linear two-terminal element array substrate 81 that are in contact with the display medium 82, glass fibers or fine resin particles are scattered, spacers 84 are provided, and then a sealing material 85 is formed. The display medium 82 is filled in the gap formed by the spacer 84 to form a matrix display device.

Problems to be Solved by the Invention In order to drive, for example, a liquid crystal display device using a non-linear two-terminal element, it is necessary to apply a sufficient voltage to the non-linear element. To achieve this, the capacitance of the non-linear element must be designed to be about 1/10 or less of the capacitance of the liquid crystal layer. Regarding the first method based on the conventional technology, when the thickness of tantalum oxide is about 500 mm, the dark voltage is 7 to IIV and the nonlinear characteristics are also extremely suitable. The capacitance of the linear element increases. Therefore, it is somewhat disadvantageous to obtain high-quality liquid crystal display characteristics with a duty of 1) 500 to 1/1000, and for this reason, the shape of the nonlinear elements is made finer, but this causes a significant deterioration in the yield of arrays. In addition, the process of photolithography, which is more complicated and time-consuming, is performed at least three times, which not only deteriorates work efficiency (but also causes a significant cost increase). , one photolithography step is included at least five to six times, which causes deterioration of work efficiency, deterioration of yield, and further increases in cost.

Means for Solving the Problems In order to solve the above-mentioned problems, the matrix display device of the present invention includes a fourteenth body layer having gaps sequentially on the substrate, and a plurality of second conductor layers provided for each of the conductor layers. a semiconductor layer consisting of a first inorganic insulating layer and a compound of arsenic (As) and selenium (Se) interposed between a conductive layer, the first conductive layer, and the second conductive layer and electrically connected in cascade; A display medium is sandwiched between a nonlinear two-terminal element array having a composite layer of a second inorganic insulating layer, and a second substrate having a strip-shaped electrode.

Operation The present invention realizes nonlinear current-voltage characteristics by the semiconductor layer, that is, the nonlinear element portion consisting of the conductor layer-inorganic insulator layer one-half layer-inorganic insulator layer-conductor layer structure. are doing.

It is currently assumed that this nonlinearity is caused to a large extent by the semiconductor layer. When measuring the current-voltage characteristics of an actual device, it shows a characteristic that can be approximated in the form I=A ・ ■“, where A and α are constants. By doing so, it is possible to increase the ratio of the on-voltage to the off-voltage applied to the picture element part, and it is possible to improve the contrast characteristics.Also, it is possible to increase the ratio of the on-voltage and off-voltage applied to the picture element part, and it is possible to improve the contrast characteristics. The dielectric constant of the compound (Se) is I
Due to the relatively small size of less than O, the shape of the ratio linear element can be made relatively large, and an improvement in yield can be expected. For example, a semiconductor layer is placed on a first conductor layer (usually a lead wire) patterned on a substrate, and then a second conductor layer (usually a part of a pixel electrode, or between the semiconductor layer and the pixel). It is possible to laminate (connection wiring connecting electrodes) by forming a film twice and performing photolithography twice in one step. However, considering that the shape of the nonlinear element can be made relatively large and that substrate heating is not required when the semiconductor layer is formed by vapor deposition, the manufacturing method of the nonlinear element used in the display device according to the present invention It turns out that it is simple. That is, the formation of the semiconductor layer on the first conductor layer patterned on the substrate is easily achieved by using a metal mask and performing mask alignment and vapor deposition. Further, the second conductor layer may also be easily formed by subsequent mask vapor deposition, depending on what constitutes the second conductor layer.

Furthermore, the inorganic insulating layer is responsible for relaxing the stress between the substrate and the semiconductor layer, contributing to uniformity of characteristics, and providing a more stable non-linear two-terminal element. Furthermore, by having a symmetrical structure of conductor layer - inorganic insulator layer - semiconductor layer - inorganic insulator layer - conductor layer structure, electrically symmetrical characteristics can be obtained, which greatly contributes to the stability of the liquid crystal. I can do it. As described above, it is possible to realize a liquid crystal display device with high display quality at low cost without reducing yield.

Embodiment Hereinafter, a matrix display device according to a typical embodiment of the present invention will be described with reference to the drawings.

As mentioned above, the first conductor layer is the lead wiring or a part thereof branched from the lead wiring, and the second conductor layer is a part of the picture element electrode or a connection for the purpose of connection to the picture element electrode. It's the wiring. Although it has been confirmed that the effects of the present invention are exhibited in any case, in this example, the following describes the case where the first conductor layer is a lead wiring and the second conductor layer is a part of a picture element electrode. shall be stated.

FIG. 1(a) shows a cross-sectional view of the structure, and FIG. 1(b) shows a plan view. In FIG. 1, 1 is a substrate, and after the first conductor layer 2 formed on the substrate 1 is battened and an inorganic insulating film 3 is formed on the entire surface of the substrate except for the lead terminal portion, a thickness of about 30 μm is formed. Alignment is performed using a mask made of magnetic stainless steel plate with predetermined holes and an aligner, and a samarium-cobalt magnet is placed from the back side of the board to bring it into close contact.
Thereafter, this is placed in a vacuum chamber for vapor deposition, and a semiconductor N4 is formed on the substrate by a resistance heating method. Thereafter, an inorganic insulating film 5 is again formed on the entire surface of the substrate except for the lead terminal portion, and then a second gA body layer 6 is formed by low-temperature sputtering. The substrate 1 has a first conductor layer 2 made of quartz glass, soda glass, etc.
The semiconductor layer 4 is formed of an alloy of arsenic and selenium, such as indium oxide (ITO) containing tin, tin oxide containing antimony, chromium, aluminum, titanium, etc. Further, the second conductor layer 6 is made of tellurium, chromium, aluminum, or the like. After measuring the current-voltage characteristics of the non-linear two-terminal element array obtained as described above, and performing alignment treatment on the surfaces of the non-linear two-terminal element array and the transparent substrate with strip-shaped electrodes, respectively. The two substrates were bonded together to form a panel, and a display medium was injected to form a liquid crystal display panel.

In one embodiment of the present invention, the substrate 1 shown in FIG. 1 is made of soda glass coated with silicon dioxide (SiO2), and the first conductor layer 2 is made of ITOl or titanium with a thickness of approximately 2000 nm. Two types of (Ti) were formed. For each of them, the semiconductor layer 4 is a compound of arsenic and selenium, with arsenic of 1 atomic %, 5 atomic %, 10 atomic %, 25 atomic %, 40 atomic %,
A total of nine types of 50 atomic %, 60 atomic %, 80 atomic %, and 85 atomic % were deposited, and the second conductor layer 6 formed a tellurium film with a thickness of approximately 500 atomic %. a first inorganic insulator layer;
Approximately 300 yttrium oxide (yz (h)) was deposited on each of the second and second inorganic insulator layers. The capacitance of the liquid crystal layer was also sufficiently small compared to the capacitance of the liquid crystal layer.When a liquid crystal display panel was manufactured using these substrates, the duty ratio was 1/1000.
, when driving a matrix with a bias ratio of 1/7, 10
: Display with a contrast of 1 or more was confirmed.

By the way, in the panel manufacturing process, formation of an alignment film,
When injecting the liquid crystal material, it is necessary to heat the substrate to at least 90°C, but if the arsenic and selenium compound constituting the semiconductor layer 4 has an arsenic content of 10 at%, it is necessary to heat the substrate to at least 90°C. The device was destroyed during heat treatment due to the significantly lower temperature. Further, in a device with an arsenic component ratio of 85 atomic %, arsenic precipitation was observed, making it impractical.

From the above, in a compound of arsenic and selenium, arsenic is 1
It was confirmed that if it is 0 at.% or more and 80 at.% or less, it has satisfactory characteristics as a non-linear two-terminal element for liquid crystal display.

In another embodiment of the present invention, the substrate 1 shown in FIG.
Soda glass is coated with silicon dioxide (SiO□), and the first conductor layer 2 is ITOl with a thickness of approximately 1500 mm.
Alternatively, two types of titanium (Ti) were formed. For each, the second conductor layer 6 was coated with a tellurium film with a film thickness of 200 and 30.
A total of nine types were deposited with 0, 500, 1,000, 2,000, 3,000, 4,000, 5,000, and 8,000 people. The semiconductor layer 4 is 3 selenide 2
About 100 people deposited arsenic (As2Se), and about 50
0 aluminum oxide (AlZ03) was formed. The nonlinearity of the current-voltage characteristics of the nonlinear two-terminal device obtained as described above was extremely large and symmetrical, and the capacitance was also sufficiently small compared to the capacitance of the liquid crystal layer. When a liquid crystal display panel was manufactured using these substrates, the duty ratio was 1/1000 and the bias ratio was 1/7.
During matrix driving, display with a contrast of 10:1 or more was confirmed.

In another embodiment of the present invention, the substrate 1 shown in FIG.
Soda glass is coated with silicon dioxide (SiO2), and the first conductor layer 2 is ITOl with a thickness of about 2,500 mm.
Alternatively, two types of titanium (Ti) were formed. For each of them, a total of six types of chromium (Cr) and aluminum (Al7 films) each having a film thickness of 500, 1,000, and 2,000 layers are deposited on the second conductor layer 6, and the semiconductor layer 4 is made up of three layers.
About 1,500 people deposited arsenic selenide (AszSe2). Approximately 500 yttrium oxide (Y203) was formed in each of the first inorganic insulating layer and the second inorganic insulating layer. The nonlinearity of the current-voltage characteristics of the nonlinear two-terminal device obtained as described above was extremely large and symmetrical, and the capacitance was also sufficiently small compared to the capacitance of the liquid crystal layer. When a liquid crystal display panel was manufactured using these substrates, a display with a contrast of 10:1 or more was confirmed during matrix driving with a duty ratio of 1/1000 and a bias ratio of 1/7.

In another embodiment of the present invention, the substrate 1 shown in FIG.
Soda glass is coated with silicon dioxide (SiO□), and the first conductor layer 2 is ITOl with a thickness of approximately 2000 mm.
or titanium (Ti), and the semiconductor layer 4 for each of them is made of diarsenic triselenide (AszSe: +
) were deposited with film thicknesses of 300, 500, 1,000, 2,000, 3,000, 4,000, 5,000, and 6,000, respectively.

A 400-layer tellurium coating is formed on the second conductor layer 6, and the first
About 300 magnesium fluoride (M g F z ) was formed in each of the inorganic insulating layer and the second inorganic insulating layer. The nonlinearity of the current-voltage characteristics of the nonlinear two-terminal device obtained as described above was extremely large and symmetrical, and the capacitance was also sufficiently small compared to the capacitance of the liquid crystal layer. When a liquid crystal display panel was manufactured using these substrates, the duty ratio was 1/1000. During matrix driving with a bias ratio of 1/7, display with a contrast of 10:1 or more was confirmed. Note that when the thickness of the inorganic insulating layer exceeds 1000 Å, it becomes difficult to electrically connect the first conductive layer, the semiconductor layer, and the second conductive layer.
Furthermore, if the thickness is less than 100 Å, pinholes will occur, causing short circuits. Therefore, the film thickness is 100 to 1
Approximately 000 people is suitable.

In the embodiments of the present invention, a metal mask was used as a method for battening the semi-quartet layer and the second conductor layer, but even if a lift-off method using a photoresist was used,
It should also be noted that similar results can be obtained when using other than liquid crystal compositions as the display medium, such as electrophoretic display devices (EPID), electroluminescent display devices (EL), electrochromic display devices (E CD), etc. Not even.

Effects of the Invention As described above, the matrix display device of the present invention includes a first conductor layer having gaps on a substrate, a first inorganic insulating layer, and a semiconductor made of a metal compound of arsenic (As) and selenium (Se). By having a structure in which a layer, a second inorganic insulator layer, and a second conductor layer are laminated, it is possible to perform a simple process without using a single photolithography process or a lift-off process as shown in the example. A non-linear two-terminal array for matrix display that does not cause defects such as peeling during the process and has highly symmetrical current-voltage characteristics and more stable characteristics has been obtained, greatly improving work efficiency and yield. In addition, it was possible to realize a matrix display device with high display quality at low cost.

[Brief explanation of the drawing]

FIG. 1 (al is a cross-sectional view of the configuration of a non-linear two-terminal element for liquid crystal display according to the present invention, FIG. 1 (bl is a plan view thereof, and FIG. 2 (
al and Fig. 3 [al is a cross-sectional view of the structure of a conventional non-linear two-terminal element, Fig. 2 (bl and Fig. 3 fb) is a layout diagram of a conventional non-linear two-terminal element, and Fig. 4 is a cross-sectional view of a conventional non-linear two-terminal element. FIG. 5, an equivalent circuit diagram of a liquid crystal display panel with terminal elements, is a configuration diagram of a matrix display panel using non-linear two-terminal elements. DESCRIPTION OF SYMBOLS 1...Substrate, 2...First conductor layer, 3.
...First inorganic insulator layer, 4...Semiconductor layer, 5...Second inorganic insulator layer, 6...Second conductor layer. Name of agent: Patent attorney Toshio Nakao Haka1 person! 1 board 6 - 2nd station eyebrow Figure 2 @ Figure 3 Figure 4 Figure 5

Claims (6)

[Claims] (1) A first conductor layer having gaps sequentially on the substrate, a plurality of second conductor layers provided for each of the conductor layers, interposed between the first conductor layer and the second conductor layer, and electrically conductive. A non-linear structure comprising a composite layer of a first inorganic insulating layer, a semiconductor layer made of a compound of arsenic (As) and selenium (Se), and a second inorganic insulating layer, which are cascade-connected. A matrix display device characterized in that a display medium is sandwiched between a two-terminal element array and a second substrate having strip-shaped electrodes. (2) The matrix display device according to claim (1), wherein in the arsenic and selenium compound constituting the semiconductor layer, the component ratio of arsenic is 10 atomic % or more and 80 atomic % or less. (3) The first conductor layer is indium oxide (In_2O_3) containing tin (Sn), tin oxide (SnO_2) containing antimony (Sb), chromium (Cr), aluminum (A
1), or titanium (Ti). (4) The second conductor layer is indium oxide (In_2O_3) containing tin (Sn), tellurium (Te), aluminum (
The matrix display device according to claim 1, wherein the matrix display device is made of any one of Al), chromium (Cr), and titanium (Ti). (5) Yttrium oxide (Y_2O_3) inorganic insulator layer
), aluminum oxide (Al_2O_3), or magnesium fluoride (MgF_2). (6) The matrix display device according to claim (1), wherein the display medium is made of any one of a liquid crystal composition, an electrophoretic display element, an electroluminescent display element, and an electrochromic display element.