JP2001305996A - Substrate for display device and method for manufacturing the same, as well as liquid crystal device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a panel substrate which is low in electric resistance in wiring and is high in the light transmittance of electrodes for display, and a liquid crystal device using the same. SOLUTION: The panel substrate 30 has a substrate 31, the plural electrodes 32 for display which are formed in parallel on the substrate 31 and a plurality of wiring 34 which are formed on the substrate 31 and are continuous with the electrodes 32 for display. The electrodes 32 for display and the wiring 34 have two-layered structures consisting of a transparent conductive layer 70 and a metallic layer 72. The width of the metallic layer 72 of the electrodes 32 for display is much narrower than the width of the transparent conductive layer 70.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a display device substrate used for a display device, a method of manufacturing the display device substrate, a liquid crystal device using the display device substrate, and an electronic device using the liquid crystal device. .

[0002]

2. Description of the Related Art In general, a simple matrix type liquid crystal device comprises a plurality of parallel display electrodes and wirings which are conductively connected to the respective display electrodes and apply a voltage, are formed on a substrate. One panel substrate is formed by arranging display electrodes on each substrate so as to face each other in a grid pattern.

In an active matrix type liquid crystal device having a structure in which a thin film diode (TFD) is formed so as to be attached to each pixel, an element substrate and a counter substrate, which are a pair of substrates, are arranged to face each other. Formed by In this case, T
An FD, a wiring connected to the TFD, and a pixel electrode as a display electrode are formed. Further, on the counter substrate, a plurality of parallel display electrodes and wirings that are conductively connected to the respective display electrodes and apply a voltage are formed. The element substrate and the counter substrate are arranged to face each other such that the pixel electrode on the element substrate and the display electrode on the counter substrate overlap.

[0004]

In the above-mentioned conventional liquid crystal device, the wiring connected to the display electrode has been increased in accordance with the so-called narrowing of the frame, in which the display is made finer and the area other than the display area is made as small as possible. Has a tendency to be particularly fine. In recent years, with the miniaturization of the wiring, the resistance of the wiring has increased, and the voltage drop of the voltage applied from the drive circuit in the wiring cannot be ignored.

In a simple matrix type liquid crystal device, an STN (Super Twisted Nematic) type liquid crystal is often used.
It is particularly susceptible to subtle changes in drive voltage.
Further, the wiring is continuously formed by being conductively connected to the display electrode, and is usually formed of a transparent conductive film, for example, an ITO (Indium Tin Oxide) film used for the display electrode, and is formed simultaneously with the display electrode. Is done. As a result, the display electrode and the wiring usually become a transparent conductive film having substantially the same thickness.

[0006] By the way, as described above, the line width of a wiring has been reduced due to miniaturization, but in order to reduce the resistance in the path of the wiring, it is conceivable to increase the thickness of the transparent conductive film. Can be However, increasing the thickness of the wiring increases the time required for film formation.
Further, when the thickness of the wiring is increased, the thickness of the display electrode formed at the same time increases, so that the light transmittance of the display electrode decreases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to reduce the electric resistance of wiring in a display device substrate, increase the light transmittance of a display electrode, and An object of the present invention is to achieve at least one of reducing time required for forming a display electrode and a wiring.

[0008]

(1) A display device substrate according to the present invention includes a plurality of display electrodes and a plurality of wirings for applying a voltage to the plurality of display electrodes. Wherein the wiring has a laminated structure of a transparent conductive layer made of the same layer of a transparent conductive layer as the display electrode, and a metal layer made of a metal having a lower resistance than the transparent conductive layer. I do.

In the display device substrate having the above structure, the wiring has a laminated structure of a transparent conductive layer and a metal layer. Therefore, the electric resistance of the wiring can be reduced as compared with the case where the wiring is formed only of the transparent conductive layer. it can. Therefore, a liquid crystal device using the present display device substrate is less likely to deteriorate display quality due to a voltage drop in wiring.

Further, since it is not necessary to increase the thickness of the transparent conductive layer in order to reduce the electric resistance of the wiring, the film in the transparent conductive layer of the display electrode, which is often formed simultaneously with the transparent conductive layer of the wiring. The thickness is not increased more than necessary. Therefore, the light transmittance of the display electrode can be increased as compared with the case where the electric resistance of the wiring is reduced only by increasing the thickness of the transparent conductive layer.

Furthermore, the thickness of the transparent conductive layer used for the display electrode and the wiring can be reduced as compared with the case where the electric resistance of the wiring is reduced only by increasing the thickness of the transparent conductive layer. Can be reduced in time required for the formation.

(2) In the display device substrate having the configuration described in the above item (1), the display electrode is made of a transparent conductive layer made of a transparent conductive layer and a metal having a lower resistance than the transparent conductive layer. It can have a laminated structure with a metal layer.

As described above, when the display electrode has a laminated structure of the transparent conductive layer and the metal layer, the electric resistance of the display electrode can be reduced as compared with the case where the display electrode is formed only of the transparent conductive layer. Further, since it is not necessary to increase the thickness of the transparent conductive layer in order to reduce the electric resistance of the display electrode, the light transmittance of the display electrode can be increased.

(3) In the display device substrate having the configuration described in the above item (2), it is desirable that the metal layer in the display electrode is narrower than the transparent conductive layer. In this case, the electric resistance of the display electrode can be reduced without substantially reducing the brightness of the display.

(4) In the display substrate having the configuration described in the above item (1) or (2), the display electrode is
The metal layer may have a laminated structure of the transparent conductive layer and the metal layer. In this case, the metal layer may partially have an opening in a portion of the laminated structure.

If the substrate for a display device of this configuration is used as a rear substrate of a pair of substrates constituting a liquid crystal device,
Since light passes through the opening of the display electrode and is reflected by the metal layer portion of the display electrode, a transflective liquid crystal device can be formed. Further, since the display electrode formed of the transparent conductive layer exists in the opening of the metal layer, the electric field applied to the liquid crystal in the region corresponding to the opening does not disturb.

(5) In the display device substrate according to any one of (1) to (4), the wiring is a wiring routed from an end of the display electrode along a periphery of the substrate. It can be. In general, the wiring is extended around the frame region of the peripheral portion of the substrate, so that the wiring distance becomes long. Therefore, if the wiring is formed by the laminated structure of the transparent conductive layer and the metal layer as in the present invention, the wiring resistance is reduced The effect is particularly great with regard to lowering the pressure.

(6) Next, a liquid crystal device according to the present invention is a liquid crystal device in which liquid crystal is sandwiched between a pair of substrates, and has a configuration described in the above (1) to (5). The device substrate is used as at least one of the pair of substrates. According to the liquid crystal device having this configuration, since the wiring has a laminated structure of the transparent conductive layer and the metal layer, the electric resistance of the wiring can be reduced as compared with the case where the wiring is formed only with the transparent conductive layer. Therefore, the possibility that the display quality is deteriorated due to the voltage drop in the wiring is low.

Further, since it is not necessary to increase the thickness of the transparent conductive layer in order to reduce the electric resistance of the wiring, the thickness of the transparent conductive layer of the display electrode, which is often formed simultaneously, is unnecessarily thick. Never be. Therefore, the light transmittance of the display electrode is higher than when the electric resistance of the wiring is reduced only by increasing the thickness of the transparent conductive layer.

Further, since the thickness of the transparent conductive layer used for the display electrode and the wiring is smaller than the case where the electric resistance of the wiring is reduced only by increasing the thickness of the transparent conductive layer, the formation of the transparent conductive layer is performed. Can be shortened.

(7) Next, the liquid crystal device according to the present invention is constituted by sandwiching a liquid crystal layer between the display device substrate having the structure described in the above item (4) and an opposing substrate opposed thereto. A transmission type display function using an opening of the metal layer as a light transmission part and a reflection type display function using a part of the metal layer as a light reflection part.

In the liquid crystal device having this configuration, since the wiring has a laminated structure of a transparent conductive layer and a metal layer, the electric resistance of the wiring can be reduced as compared with the case where the wiring is formed only by the transparent conductive layer. . Therefore, the possibility that the display quality is deteriorated due to the voltage drop in the wiring is low.

Further, since it is not necessary to increase the thickness of the transparent conductive layer in order to reduce the electric resistance of the wiring, the thickness of the transparent conductive layer of the display electrode, which is often formed simultaneously, is unnecessarily thick. Never be. Therefore, the light transmittance of the display electrode is higher than when the electric resistance of the wiring is reduced only by increasing the thickness of the transparent conductive layer.

Furthermore, the thickness of the transparent conductive layer used for the display electrode and the wiring is smaller than the case where the electric resistance of the wiring is reduced only by increasing the thickness of the transparent conductive layer. Can be shortened.

(8) Next, an electronic apparatus according to the present invention is characterized in that it has a liquid crystal device having the constitution described in the above item (6) or (7) as a display means. According to the electronic device having this configuration, it is possible to obtain an electronic device that has the above-described functions and effects of the display device and includes a display unit with high display quality.

(9) Next, a method of manufacturing a display device substrate according to the present invention is the method of manufacturing a display device substrate according to any one of the above items (1) to (5), A transparent conductive layer forming step of forming the transparent conductive layer on the substrate, a metal layer stacking step of stacking a metal layer on the transparent conductive layer, and an etching step of simultaneously etching the transparent conductive layer and the metal layer; It is characterized by having.

According to the manufacturing method of this configuration, the wiring can be formed by laminating the transparent conductive layer and the metal layer and patterning them by one etching.

(10) Next, a method of manufacturing a display device substrate according to the present invention is the method of manufacturing a display device substrate according to any one of the above items (1) to (5), A transparent conductive layer forming step of forming the transparent conductive layer on the substrate, a metal layer laminating step of laminating a metal layer on the transparent conductive layer, and the transparent conductive layer and the metal layer using a first photoresist film. A first etching step of simultaneously etching and patterning the layers, and exposing and developing the first photoresist film to form a second photoresist film having a predetermined pattern, and using the second photoresist film to form the metal And a second etching step of patterning by etching only the layer.

According to the manufacturing method having the above structure, the second photoresist film formed by exposing and developing the first photoresist film having the predetermined pattern used in the first etching process is used. After etching while leaving a part of the metal layer of the part to be the display electrode, the photoresist film is removed to form a display having a part where the transparent conductive layer and the metal layer are laminated and a part having only the transparent conductive layer. Electrode and wiring patterns can be formed.

According to such a process, a pattern in which a metal layer and a transparent conductive layer are partially laminated can be formed only by applying and removing the photoresist film once. This greatly reduces the number of steps as compared with the case where the application of the photoresist film and the removal of the photoresist film are each required twice when the transparent conductive layer and the metal layer are separately patterned. In addition, a wiring can be formed by laminating a transparent conductive layer and a metal layer and patterning them by a single etching.

(11) In the method of manufacturing a substrate for a display device according to the above mode (10), the metal layer in the display electrode is left only on an end of the transparent conductive layer by the second etching step. It is characterized by being etched so that According to the manufacturing method having this configuration, it is possible to pattern the display electrode whose electric resistance has been reduced by substantially reducing the number of steps without substantially reducing the brightness of the display.

(12) In the method for manufacturing a display device substrate according to the above mode (10), the metal layer in the display electrode may have an opening on the transparent conductive layer by the second etching step. Is characterized by being etched. According to the manufacturing method having this configuration, the display device substrate having the operation and effect described in the above item (4) can be manufactured with a small number of steps.

(13) Next, the liquid crystal device according to the present invention is a liquid crystal device in which liquid crystal is sandwiched between a pair of display device substrates. One of the display device substrates has a plurality of pixel electrodes and , A plurality of 2 formed in association with each of the pixel electrodes.
A terminal-type switching element, and the other display device substrate has a plurality of display electrodes arranged in a stripe shape facing the plurality of pixel electrodes, and a wiring connected to the display electrode. The plurality of display electrodes include a transparent conductive layer, and the wiring includes a transparent conductive layer formed of the same transparent conductive layer as the display electrode, and a metal formed of a metal having a lower resistance than the transparent conductive layer. It has a laminated structure with layers. Here, as the two-terminal switching element, for example, a TFD (Thin Film Diode) can be used.

(14) Next, the liquid crystal device according to the present invention is a liquid crystal device in which liquid crystal is sandwiched between a pair of display device substrates. One of the display device substrates has a plurality of pixel electrodes and a plurality of pixel electrodes. , A plurality of 3s formed in association with each of the pixel electrodes.
A terminal-type switching element, and the other display device substrate has a plurality of display electrodes arranged in a stripe shape facing the plurality of pixel electrodes, and a wiring connected to the display electrode. The plurality of display electrodes include a transparent conductive layer, and the wiring includes a transparent conductive layer formed of the same transparent conductive layer as the display electrode, and a metal formed of a metal having a lower resistance than the transparent conductive layer. It has a laminated structure with layers. Here, as the three-terminal switching element, for example, a TFT (Thin Film Transistor) can be used.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below more specifically with reference to the drawings.

(First Embodiment) FIG. 1 is an exploded perspective view schematically showing a liquid crystal device 10 as a display device according to the present invention. FIG. 2 is a sectional view schematically showing a sectional structure of the liquid crystal device 10 shown in FIG. As shown in these drawings, the liquid crystal device 10 includes a liquid crystal panel 14 as a display panel and a light guide plate 4 disposed on the back side of the liquid crystal panel 14.
4 having a backlight unit 40. Also,
The liquid crystal device 10 has a frame member (not shown) that protects the liquid crystal panel 14 and the backlight unit 40 and maintains a predetermined positional relationship.

In FIG. 2, the liquid crystal panel 14 is formed by arranging a first panel substrate 20 and a second panel substrate 30 so as to face each other, and these panel substrates are distributed between them. Spacer (not shown)
They are opposed to each other at a predetermined interval by the like. The first panel substrate 20 has a stripe-shaped display electrode 22 on one surface of a substrate 21 made of a transparent material such as glass or synthetic resin.
Formed as a substrate for a display device on the display surface side.

The second panel substrate 30 functions as a display device substrate in which stripe-shaped display electrodes 32 are formed on one surface of a substrate 31 made of a transparent material such as glass or synthetic resin. The display electrodes 22 of the first panel substrate 20 and the display electrodes 32 of the second panel substrate 30 are opposed to each other so as to form a lattice shape, and constitute a so-called simple matrix liquid crystal panel.

A seal member 19 is disposed on the periphery of the pair of panel substrates 20 and 30 in a substantially rectangular shape when viewed from the direction of arrow A in FIG. 2, and the two panel substrates 20 and 30 are bonded together by the seal member 19. You. A particle-shaped upper and lower conductive material 26 is mixed into the sealing material 19, and the wiring 36 on the second panel substrate 30 passes through the conductive material 26 through the conductive material 26.
The wiring 24 continuous with the display electrode 22 on the first panel substrate 20 is conductively connected. Thus, the voltage input from the terminal 39 can be applied to the display electrode 22.

In the gap between the first panel substrate 20 and the second panel substrate 30 surrounded by the seal member 19, a liquid crystal, for example, STN is passed through a liquid crystal inlet (not shown) provided in a part of the seal member 19. The liquid crystal 18 of the mold is filled. The liquid crystal injection port is sealed with a sealing material (not shown) after the liquid crystal injection processing.

The first polarizing plate 16 is disposed outside the first panel substrate 20, and the second polarizing plate 17 is disposed outside the second panel substrate 30. Further, the phase difference plate 12 is disposed between the first polarizing plate 16 and the first panel substrate 20. The phase difference plate 12 is composed of the second polarizing plate 17 and the second panel substrate 3.
0 or the first panel substrate 20
And the second panel substrate 30.

The liquid crystal panel 14 has a plurality of terminals 39 in an overhang region 38 where the second panel substrate 30 overhangs from the first panel substrate 20. Each terminal 39 is connected to a corresponding terminal of the wiring substrate 64 shown in FIG. 1, for example, a flexible substrate. A drive IC (not shown) for driving the display electrodes 22 and 32 (see FIG. 2) of the liquid crystal panel 14 is mounted on the wiring board 64, and the wiring board 64 connected to the output terminal of the drive IC. And the terminal 39 formed on the second panel substrate 30 are connected, and a driving voltage is applied to each of the display electrodes 22 and 32.

In the liquid crystal panel 14, the plurality of display electrodes 22 formed on the first panel substrate 20 and the second
A voltage difference between signals supplied to the display electrodes 32 of the panel substrate 30 is applied to the liquid crystal 18, the orientation of the liquid crystal molecules is controlled, and the display is turned on or off.

A mounting area for a driving IC is provided on the first panel substrate 20 or the second panel substrate 30 so that the driving IC
To the first panel substrate 20 or the second panel substrate 30
(Chip On Glass), and a signal or voltage may be supplied to a driving IC on a panel substrate via a flexible substrate.

In FIG. 2, the pair of panel substrates 20 and 30 are drawn widely apart, but this is for clarity of illustration, and actually, the pair of panel substrates 20 and 30 are actually illustrated. Face each other with a narrow gap of several μm to several tens μm. Further, the first polarizing plate 16 and the retardation plate 12 are drawn apart from the first panel substrate 20, and the second polarizing plate 17
Are drawn away from the second panel substrate 30, but in reality, the retardation plate 12 is almost in contact with the first panel substrate 20, and the second polarizer 17 is almost in contact with the second panel substrate 30. In this state, the first polarizing plate 16 is substantially in contact with the retardation plate 12. Further, although only a few stripe-shaped display electrodes 22 and 32 are shown, they are actually provided as a large number of stripe-shaped electrodes corresponding to the resolution of matrix display.

In FIG. 1, the backlight unit 40
Has a fluorescent tube 50 as a light source, a light guide plate 44, a lens sheet 42 as a light diffusion plate, a backlight fixing frame 56, and a reflector 60. An output terminal of an inverter (not shown) is connected to the fluorescent tube 50 via a connection unit 51, and a predetermined voltage is applied to the fluorescent tube 50 by the inverter.

The light guide plate 44 is made of, for example, a transparent synthetic resin, and a fluorescent tube 50 as a light source is arranged in a state almost in contact with the end surface 45. The light from the fluorescent tube 50 enters the light guide plate 44 from the end face 45 and propagates inside the light guide plate 44, and is emitted from the light exit surface facing the liquid crystal panel 14 to illuminate the entire display area of the liquid crystal panel 14. The light guide plate 44
Except for the substrate overhang region 38 of the liquid crystal panel 14, the liquid crystal panel 14 has a planar shape substantially corresponding to the planar shape of the liquid crystal panel 14.

The light guide plate 44 is formed to have a thick wedge-shaped cross section on the fluorescent tube 50 side. When the light guide plate 44 has such a shape, the light guide plate 44
The amount of light radiated toward the liquid crystal panel 14 is uniformized in the vicinity of the fluorescent tube 50 and at a position distant from the fluorescent tube 50.

The lens sheet 42 is disposed on the front side of the light guide plate 44, and irradiates uniform light to the entire display area of the liquid crystal panel 14 by diffusing light emitted from the light guide plate 44. Then, the reflector 60 covers the periphery of the fluorescent tube 50 except for the side of the light guide plate 44, and reflects the light from the fluorescent tube 50 toward the light guide plate 44. In FIG. 1, the fluorescent tube 50 is illustrated as extending outside the reflector 60, but in actuality, the fluorescent tube 50 is connected to the reflector 6.
It is assembled so that it can be housed inside the 0.

Power is supplied to the fluorescent tube 50 of the backlight unit 40 by an inverter (not shown).
Specifically, this inverter, for example,
A DC voltage of 250 V is output as an AC voltage of 250 V and 100 kHz and supplied to the fluorescent tube 50. Note that an LED is used as a light source instead of the fluorescent tube 50, and L
The ED may be arranged.

The backlight fixing frame 56 has a bottom portion 57 and fixes the backlight unit 40 from the back side. In addition, the backlight fixing frame 56 has a plurality of positioning portions 58 provided upright from the bottom portion 57. These positioning portions 58 are provided on the corresponding end faces 4 of the light guide plate 44.
6 and 47, and the light guide plate 4
4 are formed so as to abut against the end surfaces 46 and 47,
Thus, the light guide plate 44 is positioned at a predetermined position in a plane substantially parallel to the bottom surface portion 57.

The plurality of positioning portions 58 are provided on the light guide plate 4.
Of the end faces 4 where the fluorescent tube 50 is not disposed
6 and 47 are formed in a planar shape that almost covers them in close contact with each other. Then, the positioning portion 58 and the bottom portion 5
7 is formed with sufficient light reflectance on the side facing the light guide plate 44, so that light from the fluorescent tube 50 can be used with high efficiency. The backlight fixing frame 56
Is formed so that the above-described reflector 60 is integrated.

FIG. 3 is a plan view schematically showing a state where the first panel substrate 20 is viewed from the front side.
Are shown in a see-through state. FIG. 4 is a plan view schematically showing a state where the second panel substrate 30 is viewed from the front side. When the liquid crystal panel 14 shown in FIG. 1 is viewed from the display surface side, the second panel substrate 30 shown in FIG. 4 is superimposed on the back side of the first panel substrate 20 shown in FIG. The relationship is set such that the projecting area 38 of the second panel substrate 30 projects outside the first panel substrate 20. Note that the schematic cross-sectional structure of the liquid crystal panel shown in FIG. 2 is a cross-sectional structure along the line SS shown in FIG. 3 and FIG.

In FIG. 3, the first panel substrate 20 has a display electrode 2 formed as a predetermined pattern on a substrate 21.
2 and a wiring 24 extending from each display electrode 22. The display electrode 22 functions as one of a scanning electrode and a signal electrode. Further, an end of the wiring 24 is formed as a pad 25 which is a terminal to which the upper and lower conductive material 26 (see FIG. 2) is connected.

In FIG. 4, the second panel substrate 30 has a display electrode 32, a wiring 34 and a wiring 36. The plurality of display electrodes 32 are formed in parallel on the substrate 31 as a predetermined pattern. The display electrode 32 functions as the other of the scanning electrode and the signal electrode. The wiring 34 extends from each of the display electrodes 32, is routed along the periphery of the substrate 31, and has one end extending to the overhang region 38 of the second panel substrate 30 to be a terminal 39. The overhang area 38 is an area that protrudes from the opposing first panel substrate 20 in plan view.

One end 37 of the wiring 36 is connected to the upper and lower conductive material 2.
6, the pad 25 serving as a connection terminal at the end of the wiring 24 formed on the first panel substrate 20 and the pad 37 are connected to each other via the upper and lower conductive members 26. They are conductively connected to each other. The upper and lower conductive members 26 are conductive particles mixed in the sealing member 19 as shown in FIG. The other end of the wiring 36 also extends to the overhang region 38 to form an input terminal 39.

Each terminal 39 is formed as a part of the wiring 34, 36 and is electrically connected to the corresponding display electrode 22, 32. The display electrode 22 of the first panel substrate 20 is
The wiring 24 formed on the first panel substrate 20, the vertical conductive material 26, and the wiring 36 formed on the second panel substrate 30 are connected to corresponding input terminals 39.

In FIG. 3, an alignment film (not shown) made of, for example, polyimide is applied on the surface of the substrate 21 on which the display electrodes 22 and the like are formed so as to cover the display electrodes 22 and the like. Is rubbed at a predetermined angle. 4, an alignment film (not shown) made of, for example, polyimide is applied to the surface of the substrate 31 on which the display electrodes 32 and the like are formed so as to cover the display electrodes 32 and the like.
Further, the alignment film is rubbed at a predetermined angle.

FIG. 5 is an enlarged schematic plan view showing one display electrode 32 on the second panel substrate 30 and a wiring 34 continuing from the display electrode 32. FIG. 6A shows a wiring 3 according to the line FF in FIG.
FIG. 6B schematically shows a cross-sectional structure of FIG.
The cross-sectional structure of the display electrode 32 is schematically shown along line G.

In FIG. 5, the display electrode 32 and the wiring 3
4 indicates that the surface 72 is a metal layer made of a low-resistance metal such as aluminum. A region 70 of the display electrode 32 that is not shaded has a surface of ITO (Indium Tin Oxide).
And the like, indicating a transparent conductive layer made of a transparent conductive film.

As is clear from FIGS. 6A and 6B, the wiring 34 and the display electrode 32 are made of a transparent conductive layer 70 made of ITO and a metal having a lower resistance than the transparent conductive layer 70. It is formed by lamination with the layer 72. In addition,
In the display electrode 32, the transparent conductive layer 70 is formed over the entire width of the display electrode 32.
Is formed on one edge in the width direction of the transparent conductive layer 70 with a width much smaller than the width of the transparent conductive layer 70.

On the other hand, in the wiring 34, the transparent conductive layer 7
Both the 0 and the metal layer 72 extend over the entire width of the wiring 34 and are formed to have substantially the same width as each other. This makes it possible to sufficiently reduce the electric resistance of the wiring 34 that is generally formed to have a much smaller width than the display electrode 32. Although not shown, the second panel substrate 30
The other wiring 36 formed on the wiring 3 is also the wiring 3 shown in FIG.
4, the transparent conductive layer 70 and the metal layer 72
And are laminated with substantially the same width.

The wiring 24 and the display electrode 22 formed on the first panel substrate 20 shown in FIG. 3 facing the second panel substrate 30 shown in FIG.
4 and the display electrode 32, a laminated structure of a transparent conductive layer 70 made of ITO or the like and a metal layer 72 made of aluminum or the like can be used.

As described above, in the first panel substrate 20 and the second panel substrate 30 of this embodiment, that is, in the display device substrate, the wiring 24 in FIG. 3 and the wiring 34 and 36 in FIG. Layer 70 and metal layer 72
And the wirings 24, 34,
The electrical resistance of these wirings 24, 34, 36 can be reduced as compared with the case where 36 is formed only by the transparent conductive layer 70. Therefore, the liquid crystal device 10 using the panel substrates 20 and 30 according to the present embodiment can
The display quality is unlikely to degrade due to the voltage drop at 4,36.

Further, since it is not necessary to increase the thickness of the transparent conductive layer 70 in order to reduce the electric resistance of the display electrodes 22 and 23, the light transmittance of the display electrodes 22 and 32 can be increased. . In the display electrodes 22 and 32, the transparent conductive layer 70 is formed over the entire width of the display electrode 22 and the like, but the metal layer 72 is formed to have a much smaller width than the width of the transparent conductive layer 70. Therefore, the electric resistance of the display electrodes 22 and 32 can be reduced without substantially lowering the brightness of the display due to the presence of the metal layer 72.

In the first panel substrate 20 of FIG. 3, since the length of the wiring 24 is short, the wiring 24 and the display electrode 22 may be formed only of the transparent conductive layer 70 made of ITO. Further, since the length of the wiring 36 in FIG. 4 is also short, the wiring 36 may be formed only of the transparent conductive layer 70 of ITO.

By the way, in FIG. 3, the display electrode 22
Is often formed simultaneously with the transparent conductive layer 70 forming the wiring 24. In FIG. 4, the transparent conductive layer 70 forming the display electrode 32 is often formed simultaneously with the transparent conductive layer 70 forming the wiring 34 and the wiring 36. In the present embodiment, the wirings 24, 3
4 and 36 have a two-layer structure of the transparent conductive layer 70 and the metal layer 72, so that it is not necessary to increase the thickness of the transparent conductive layer 70 in order to reduce the electric resistance of the wirings 24, 34 and 36. Therefore, the transparent conductive layer 70 of the display electrode 22 formed simultaneously with the transparent conductive layer 70 of the wiring 24 and the display electrode 32 formed simultaneously with the transparent conductive layer 70 of the wiring 34 and the wiring 36 are unnecessarily thick. Never be. Therefore, only by increasing the thickness of the transparent conductive layer 70, the wirings 24, 3
The light transmittance of the display electrode 22 of FIG. 3 and the display electrode 32 of FIG. 4 can be increased as compared with the case where the electric resistance of the display electrodes 4 and 36 is reduced.

Further, in the liquid crystal device substrate of the present embodiment, compared to the case where the electric resistance of the wiring 24 of FIG. 3 and the wirings 34 and 36 of FIG. 4, the thickness of the transparent conductive layer 70 used for the display electrode 22 and the wiring 24 can be reduced, and the thickness of the display electrode 32 and the transparent conductive layer 70 of the wirings 34 and 36 in FIG. Therefore, the panel substrate 2
The time required for forming 0, 30 can be reduced.

Hereinafter, a method for manufacturing the first panel substrate 20 shown in FIG. 3 and the second panel substrate 30 shown in FIG. 4 will be described with reference to embodiments.

First panel substrate 20 and second panel substrate 3
0, a display electrode and a wiring formed by laminating a transparent conductive layer and a metal layer include a transparent conductive layer forming step, a metal layer laminating step, a first photoresist film forming step, a first etching step, It is manufactured including various processes such as a 2 photoresist film forming process and a second etching process.

FIGS. 7A to 7 are schematic cross-sectional views illustrating a manufacturing process for the second panel substrate 30.
7A shows a transparent conductive layer forming step and a metal layer laminating step, FIG. 7B shows a first photoresist film forming step, and FIG. 7C shows a first etching step. FIG. 7D shows a second photoresist film forming step, and FIG. 7E shows a second etching step. 7A to 7E, the manufacturing process of the display electrode 32 is shown on the left side, and the manufacturing process of the wiring 34 is shown on the right side. The display electrode 32 and the wiring 34
Although only one manufacturing process is shown for each, a large number are actually formed simultaneously.

First, in a transparent conductive layer forming step shown in FIG. 7A, for example, an IT is formed on a transparent substrate 31 made of a transparent material such as glass by sputtering or the like.
A transparent conductive layer made of O is formed. Next, in the metal layer laminating step also shown in FIG.
On the metal layer 0, a metal layer 72 made of, for example, aluminum is laminated.

Then, in a first photoresist film forming step shown in FIG. 7B, a photoresist film is applied,
The display electrode 32 and the wiring 34 are exposed and further developed.
The first photoresist film 74 having a predetermined pattern corresponding to the above pattern is formed.

Next, in the first etching step shown in FIG. 7C, the transparent conductive layer 70 and the metal layer 72 are simultaneously etched using the first photoresist Then, the wiring electrode 34 is patterned into a shape in plan view.

Then, in the second photoresist film forming step shown in FIG. 7D, the first photoresist film 74 remaining on the metal layer 72 is again applied to the region where the display electrode 32 is formed. After exposure and development, the transparent conductive layer 7
A second photoresist film 76 having a predetermined pattern is formed by removing the photoresist film in a region where 0 is to be formed. In the second photoresist film 76, in the region where the wiring 34 is formed, the photoresist film is left as it is.

Next, in a second etching step shown in FIG. 7E, only a part of the metal layer 72 in a region corresponding to the display electrode 32 is etched and patterned using the second photoresist. This etching is
The etching is performed at an etching rate different from that of the first etching step, and a part of the metal layer 72 is etched without substantially etching the transparent conductive layer 70.

Finally, the second photoresist film 76 is removed by, for example, ashing to obtain the structure shown in FIG.
The wiring 34 and the display electrode 32 shown in FIGS. 6A and 6B are formed.

As described above, according to the method of manufacturing a panel substrate according to the present embodiment, the first photoresist film 74 having the predetermined pattern used in the first etching step shown in FIG. Then, using the second photoresist film 76 formed by the development, the second etching process shown in FIG. (2) By removing the photoresist film 76, the display electrode 32 including the transparent conductive layer 70 and the thin metal layer 72 can be formed.

According to such a process, the display electrode 32 having the thin metal layer 72 can be formed only by applying and removing the photoresist film once. This greatly reduces the number of steps as compared with the case where the transparent conductive layer 70 and the metal layer 72 are separately patterned, in which the application of the photoresist film and the removal of the photoresist film are each required twice. .

Further, according to the panel substrate manufacturing method of the present embodiment, the wiring 34 can be formed by laminating the transparent conductive layer 70 and the metal layer 72 and patterning them by one etching.

In the above description, the second panel substrate 3
Although the method for manufacturing the panel substrate according to the present invention has been described by taking the display electrode 32 and the wiring 34 of 0 as an example, the wiring 36 also has the same structure as that of the wiring 34 and has a laminated structure of a transparent conductive layer and a metal layer. Wiring can be formed. Further, the display electrodes 22 and the wirings 24 of the first panel substrate 20 shown in FIG. 3 can be formed by the same manufacturing method as that of the second panel substrate 30, although the display electrodes and the wirings have different pattern shapes. .

Further, in the present embodiment, FIG.
The transparent conductive layer 70 constituting the display electrode 32 as shown in FIG.
The upper metal layer 72 is arranged only by the end of the transparent conductive layer 70. However, if there is no problem in the light transmittance of the display electrode, the arrangement position of the metal layer 72 is not the end of the transparent conductive layer 70. For example, it may be near the center.

(Second Embodiment) In the first embodiment described above, a case where a transmission type liquid crystal device is formed using a panel substrate, that is, a display device substrate, has been described as an example. On the other hand, in the present embodiment, one panel substrate in the first embodiment,
For example, the second embodiment differs from the first embodiment in that a panel substrate having a structure in which a metal layer of a display electrode has a slit is used instead of the second panel substrate 30. The other points are configured in the same manner as in the first embodiment, and a description of those points will be omitted. In the drawings, the same elements as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

FIG. 9 is a schematic plan view showing a second panel substrate 80 used in the present embodiment, and corresponds to FIG. 5 in the first embodiment. FIG. 10 shows a cross-sectional structure taken along line GG of FIG. 9, and corresponds to FIG. 6B in the first embodiment. In the present embodiment, a transflective liquid crystal device is formed by using the second panel substrate 80 instead of the second panel substrate 30 in the first embodiment.

In the second panel substrate 80, the display electrode 82 has a two-layer structure of the transparent conductive layer 70 and the metal layer 72 over the entire area thereof, and a plurality of slits 84 as openings are formed in the metal layer 72. The distribution is provided. Then, as a material of the metal layer 72, a highly reflective material such as aluminum, copper, silver or gold is used. Thus, even when the slit 84 is provided in the metal layer 72, the display electrode 82
Since the transparent conductive layer 70 is provided also in the region of the slit 84, an appropriate electric field can be applied to the liquid crystal also in the region of the slit 84 regardless of the size of the slit 84.

In the case of such a transflective liquid crystal device, in the case of transmissive display, illumination light from the back side of the second panel substrate 80 is passed through the slit opened in the metal layer 72. Since light is transmitted through the liquid crystal layer 80 and enters the liquid crystal layer 18, a transmissive display can be performed. On the other hand, in the case of the reflective display, the light transmitted through the liquid crystal layer 18 from the first panel substrate 20 facing the second panel substrate 80 can be reflected on the surface of the metal layer 72, so that the reflective display is performed. be able to.

In the present embodiment, a voltage can be applied to the liquid crystal layer 18 by the metal layer 72 as long as the slit 84 is small, regardless of whether the display is a transmission type display or a reflection type display. When the slit 84, which is an opening, is enlarged, the slit 7 is formed not by the metal layer 72 but by the transparent conductive layer 70 in the area of the slit.
2 will be driven.

In the liquid crystal device 10 using the panel substrate 80 according to the present embodiment, there is a low possibility that the display quality is deteriorated due to a voltage drop in the wiring 34 and the display electrode 82. Further, since the wiring 34 and the display electrode 82 have a two-layer structure of the transparent conductive layer 70 and the metal layer 72, the thickness of the transparent conductive layer 70 is increased in order to reduce the electric resistance of the wiring 34. The transparent conductive layer 70 of the display electrode 82 that is not necessary and is often formed simultaneously with the transparent conductive layer 70 of the wiring 34
Does not become unnecessarily thick. Therefore, the light transmittance of the display electrode 82 can be increased.

Further, since the thickness of the transparent conductive layer 70 can be reduced, the time required for forming the panel substrate 80 can be reduced.

In the present embodiment, the method for manufacturing the display electrode 82 is the same as the manufacturing method described with reference to FIG. 7, in which the transparent conductive layer forming step, the metal layer laminating step, and the first photoresist film forming step are performed. It comprises various steps such as a step, a first etching step, a second photoresist film forming step, and a second etching step. Therefore, after the transparent conductive layer 70 and the metal layer 72 are simultaneously etched by the first photoresist 74, the first photoresist 74 is exposed and developed again to form a pattern of the second photoresist 76, and the slits 84 of the metal layer 72 are formed. Is etched.

(Third Embodiment) In each of the above embodiments,
Although the case where the present invention is applied to a simple matrix type liquid crystal device has been illustrated, the present invention can also be applied to an active matrix type liquid crystal device using a two-terminal switching element such as a TFD. Such an active matrix type liquid crystal panel is composed of, for example, an element substrate and a counter substrate, which are a pair of substrates facing each other with a TN type liquid crystal layer interposed therebetween.

Here, the element substrate includes, for example, a plurality of wirings arranged in a stripe, a TFD provided for each pixel along the wirings, and a transparent conductive layer connected to the wirings via the TFDs. Formed by the pixel electrode. On the counter substrate facing the element substrate, wide display electrodes are formed in a stripe shape so as to intersect with the arrangement of the pixel electrodes on the element substrate side.

The above-mentioned element substrate and the above-mentioned counter substrate are bonded so that the pixel electrode on the element substrate and the display electrode on the counter substrate are opposed to each other with the liquid crystal interposed therebetween, whereby a liquid crystal device is formed. . In this liquid crystal device, one of the wiring on the element substrate and the display electrode on the counter substrate functions as a scanning electrode, and the other functions as a signal electrode.

Also in such an active matrix type liquid crystal device of the TFD system, the wiring formed on the display substrate constituting the opposing substrate is formed according to the present invention by a laminated structure composed of a transparent conductive layer and a metal layer. Thereby, the same operation and effect as those of the above-described embodiment can be obtained.

The TFD type active matrix liquid crystal device will be described below with reference to the drawings.

FIG. 12 is an enlarged view showing a main part of a TFD type active matrix type liquid crystal device using a display device substrate according to the present invention, particularly, several pixels. The overall structure of the liquid crystal device can be set, for example, as shown in FIG. The liquid crystal device 1 is an active matrix type liquid crystal device using a two-terminal type active element TFD (Thin Film Diode) as an active element, and uses a reflective display and an illumination device using external light such as natural light. This is a transflective liquid crystal device of a type capable of selectively performing the transmissive display, and a COG (Chip On Glass) type liquid crystal device of a type in which a liquid crystal driving IC is directly mounted on a substrate.

In the liquid crystal device 1, in FIG. 15, a first panel substrate 2a and a second panel substrate 2b are bonded together by a sealing material 3, and furthermore, the first panel substrate 2a, the second panel substrate 2b and the sealing material 3 It is formed by enclosing a liquid crystal in an enclosed gap, that is, a cell gap. In addition, the liquid crystal driving ICs 4a and 4b are directly mounted on the surface of the substrate overhang portion 38 of the one panel substrate 2a which protrudes outside the other panel substrate 2b.
The second panel substrate 2b is a substrate on which a TFD is formed, that is, an element substrate, and the first panel substrate 2a is a substrate facing the element substrate, that is, a counter substrate.

In the internal region of the second panel substrate 2b surrounded by the sealing material 3, a plurality of pixel electrodes are formed in a dot matrix arrangement in the row direction XX and the column direction YY. A stripe-shaped electrode is formed in an inner region of the first panel substrate 2a surrounded by the sealing material 3, and the stripe-shaped electrode is arranged to face a plurality of pixel electrodes on the second panel substrate 2b side.

A portion sandwiching the liquid crystal is formed by a stripe-shaped electrode on the first panel substrate 2a and one pixel electrode on the second panel substrate 2b, and a plurality of these pixels are surrounded by the sealing material 3. The display area V is formed by arranging them in a dot matrix in the internal area to be formed. The liquid crystal driving ICs 4a and 4b control the orientation of the liquid crystal for each pixel by selectively applying a scanning signal and a data signal between opposed electrodes in a plurality of pixels. The light passing through the liquid crystal is modulated by the alignment control of the liquid crystal, and an image such as a character or a number is displayed in the display region V.

FIG. 12 shows a display area V in the liquid crystal device 1.
Are enlarged in cross-sectional structure of several of the plurality of pixels constituting the pixel. FIG. 13 shows a cross-sectional structure of one pixel portion.

In FIG. 12, the first panel substrate 2a is
Substrate 6a formed of glass, plastic, etc.
And a light reflecting film 61 formed on the inner surface of the substrate 6a.
And a color filter 62 formed on the light reflection film 61, and a transparent striped display electrode 63 formed on the color filter 62. An alignment film 71a is formed on the display electrode 63 as shown in FIG. A rubbing process is performed on the alignment film 71a as an alignment process. The display electrode 63 is formed of a transparent conductive material such as ITO (Indium Tin Oxide).

The second panel substrate 2b opposed to the first panel substrate 2a includes a substrate 6b formed of glass, plastic, or the like, and a TFD as an active element functioning as a switching element formed on the inner surface of the substrate 6b. (Thin Film Diode) 67 and a pixel electrode 69 connected to the TFD 67. As shown in FIG. 13, an alignment film 71b is formed on the TFD 67 and the pixel electrode 69, and a rubbing process is performed on the alignment film 71b as an alignment process. The pixel electrode 69 is made of, for example, ITO
(Indium Tin Oxide) and the like.

The color filter 62 belonging to the first panel substrate 2a has R (red), G (green), B (blue) or C (cyan) at a position facing the pixel electrode 69 on the second panel substrate 2b. It has one of the color picture elements 62a of each color such as M (magenta) and Y (yellow), and has a black mask 62b at a position not opposed to the pixel electrode 69.

In FIG. 13, the distance between the first panel substrate 2a and the second panel substrate 2b, ie, the cell gap, is maintained by the spherical spacers 54 dispersed on the surface of one of the substrates, and the dimension is maintained. Liquid crystal L is sealed in the cell gap.

As shown in FIGS. 13 and 14, the TFD 67 is formed on a first metal layer 65, an insulating layer 66 formed on the surface of the first metal layer 65, and formed on the insulating layer 66. And the second metal layer 68. As described above, the TFD 67 has a laminated structure including the first metal layer / insulating layer / second metal layer, so-called MIM (Metal Insulator Met).
al) It is composed of a structure.

The first metal layer 65 is formed of, for example, tantalum alone or a tantalum alloy. First metal layer 6
When a tantalum alloy is used as 5, for example, tungsten, chromium, molybdenum,
Elements belonging to Groups 6 to 8 in the periodic table such as rhenium, yttrium, lanthanum, and dysprolium are added.

The first metal layer 65 is formed integrally with the first layer 79a of the line wiring 79. The line wiring 79 is formed in a stripe shape with the pixel electrode 69 interposed therebetween, and functions as a scanning line for supplying a scanning signal to the pixel electrode 69 or a data line for supplying a data signal to the pixel electrode 69.

The insulating layer 66 is made of, for example, tantalum oxide (Ta ₂ O ₃ ) formed by oxidizing the surface of the first metal layer 65 by anodic oxidation.
When the first metal layer 65 is anodized, the surface of the first layer 79a of the line wiring 79 is also oxidized at the same time, and a second layer 79b made of tantalum oxide is similarly formed.

The second metal layer 68 is formed of a conductive material such as Cr. The pixel electrode 69 is formed on the surface of the substrate 6b such that a part thereof overlaps the tip of the second metal layer 68. Note that an underlayer may be formed on the surface of the substrate 6b using tantalum oxide or the like before forming the first metal layer 65 and the first layer 79a of the line wiring. This prevents the first metal layer 65 from peeling off from the base by heat treatment after the deposition of the second metal layer 68,
This is for preventing impurities from diffusing into the metal layer 65.

In FIG. 12, a retardation plate 52a is mounted on the outer surface of the substrate 6a by bonding or the like, and a polarizing plate 53a is mounted on the phase difference plate 52a by bonding or the like. A retardation plate 52 is provided on the outer surface of the substrate 6b.
b is attached by sticking or the like,
A polarizing plate 53b is mounted on the “b” by bonding or the like.

For example, STN (Super Twisted Nematic)
When a liquid crystal or the like is used, wavelength dispersion may occur in light passing through the liquid crystal and coloring may occur in a display image. Phase difference plate 5
Reference numerals 2a and 52b denote optically anisotropic bodies used to remove such coloring, and are constituted by a film formed by uniaxially stretching a resin such as polyvinyl alcohol, polyester, polyetheramide, or polyethylene. it can.

The polarizing plates 53a and 53b are film-shaped optical elements having a function of emitting linearly polarized light in one direction with respect to the incidence of natural light.
It can be formed by sandwiching between (cellulose triacetate) protective layers. The polarizing plates 53a and 53b are usually arranged so that their transmission polarization axes are different from each other.

The light reflecting film 61 is formed of a light reflecting metal such as aluminum, for example, and is provided at a position corresponding to each pixel electrode 69 belonging to the second panel substrate 2b, that is, at a position corresponding to each pixel. Opening 49 is formed.

The display electrodes 63 shown in FIG. 12 extend in the column direction YY in FIG.
5, the pad 25 is electrically connected to the output terminal of the liquid crystal driving IC 4b mounted on the substrate overhang portion 38. The wiring 24 has, for example, a two-layer structure including a transparent conductive layer 70 and a metal layer 72 laminated thereon, as shown in FIG. In addition, if necessary, the display electrode 63 is also provided as shown in FIG.
It has a two-layer structure including a wide transparent conductive layer 70 and a narrow metal layer 72 laminated thereon.

Since the liquid crystal device 1 according to the present embodiment is configured as described above, when the liquid crystal device 1 performs a reflection type display, the liquid crystal device 1 is viewed from the viewer side, that is, from the second panel substrate 2b side in FIG. External light entering the inside of the liquid crystal device 1 is
After passing through the liquid crystal L, the light reaches the light reflection film 61, and the reflection film 61
And is supplied to the liquid crystal L again. The orientation of the liquid crystal L is controlled for each pixel by a voltage applied between the pixel electrode 69 and the stripe-shaped display electrode 63, that is, a scanning signal and a data signal. The light is modulated for each pixel, whereby an image such as a character or a number is displayed on the observer side.

On the other hand, when the liquid crystal device 1 performs a transmissive display, an illuminating device disposed outside the first panel substrate 2a, a so-called backlight 59, emits light. 52a, substrate 6a, light reflection film 61
Is supplied to the liquid crystal L after passing through the opening 49, the color filter 62, the display electrode 63, and the alignment film 71a. Thereafter, display is performed in the same manner as in the case of the reflective display.

As described above, in the present embodiment, the wiring 2 connected to the display electrode 63 formed on the counter substrate 2a is formed.
Since 4 has a laminated structure of the transparent conductive layer 70 and the metal layer 72, the electric resistance of the wiring 24 can be reduced as compared with the case where the wiring 24 is formed only of the transparent conductive layer 70. Therefore, the liquid crystal device 1 has a low possibility that the display quality is deteriorated due to the voltage drop in the wiring 24.

In addition, since it is not necessary to increase the thickness of the transparent conductive layer 70 in order to reduce the electric resistance of the wiring 24,
The thickness of the transparent conductive layer 70 of the display electrode 63, which is often formed simultaneously with the transparent conductive layer 70 of the wiring 24, does not become unnecessarily thick. Therefore, the light transmittance of the display electrode 63 can be increased as compared with the case where the electric resistance of the wiring 24 is reduced only by increasing the thickness of the transparent conductive layer 70.

Furthermore, the thickness of the transparent conductive layer 70 used for the display electrode 63 and the wiring 24 can be reduced as compared with the case where the electric resistance of the wiring 24 is reduced only by increasing the thickness of the transparent conductive layer 70. In addition, the time required for forming the counter substrate 2a, that is, the display device substrate can be reduced.

(Fourth Embodiment) The present invention relates to a thin film transistor (TFT: ThinFi
The present invention can also be applied to an active matrix liquid crystal device having an lm transistor attached to each pixel. In this liquid crystal device, for example, an element substrate on which a TFT is formed and a counter substrate facing the element substrate are formed by a TN (Twisted Nema).
tic) type liquid crystal layers and the like.

On the element substrate, for example, a scanning line and a data line intersecting with each other, a TFT having a gate connected to the scanning line and a source connected to the data line,
And a pixel electrode made of a transparent conductive layer connected to the drain of the pixel. A wide display electrode, that is, a common electrode is formed in a stripe shape on the counter substrate so as to overlap with the horizontal arrangement of pixel electrodes.

In this liquid crystal device, the level of the common voltage applied to the display electrode is switched for each pixel row, that is, for each horizontal scanning period and for each vertical scanning period, so that the liquid crystal between the pixel electrode and the display electrode is switched. AC drive. This driving method
This is called 1H common swing drive.

Also in such an active matrix type liquid crystal device of the TFT type, the wiring formed on the display substrate constituting the opposing substrate is formed according to the present invention by a laminated structure composed of a transparent conductive layer and a metal layer. Thereby, the same operation and effect as the above-described embodiment can be obtained.

The TFT active matrix liquid crystal device will be described below with reference to the drawings.

FIG. 17 shows a circuit configuration of the liquid crystal device according to the present embodiment. In this figure, an active matrix area 110 includes pixel TFTs 108 in N rows × M columns.
Are arranged, and N scanning lines connected to the gate electrodes of these pixel TFTs and M (= m × n) signal lines connected to their source regions are formed. These M
Analog switch TFTs (20-11 to 20-n
m) is connected.

The analog switch TFT is divided into n blocks with m adjacent blocks as one block, and the analog switch TFTs (20-11, 20-12 to 20-1m) are the first block. -21, 20-22 to 20-2m) is the second block, and ... (20-n1, 20-n2 to 20-nm) is n
Be the first block. The adjacent analog switch TFTs (20-11, 20-1) included in the same block
The gate electrodes 2 to 20-1m) are commonly connected by a first wiring 22-1. Similarly, each block (20-21, 20-2
The gate electrodes of the (20-n1, 20-n2 to 20-nm) analog switch TFTs are the first wirings, respectively.
Connected in common by 22-2,……, 22-n.

The analog switch TFTs (20-11, 20-21,..., 20-
The source region of n1) is commonly connected by the second wiring 24-1. Similarly, the analog switch TFT (20-1
2,20-22, ~, 20-n2) ... ...... (20-1m, 20-2m, ~, 20-nm)
, Are the second wirings 24-2,..., 24-m
Connected in common.

As described above, the analog switch TFT is divided into n blocks each having m pieces, and the ON / OFF of the analog switch TFT is controlled by a control signal applied to the first wiring, thereby reducing the number of terminals of the signal line to 1 / n. can do. That is, when there is no analog switch TFT, the number of terminals of the M signal lines can be reduced to m (= M / n). Then, the data driver has m second wirings 24-1 to 24-m
, The number of data drivers and the number of terminals can be reduced, and downsizing and cost reduction of the device can be achieved.

In the liquid crystal device of this embodiment, the second wiring 24-
Analog switch TFT 20-11 to 20 through 1 to 24-m
It is desirable that the amplitude of the input signal supplied to the -nm source region be 5 V or less. By doing so, the amount of shift of the threshold voltage of the analog switch TFT can be reduced, whereby reliability can be ensured and display quality can be improved.

FIG. 22 shows a measurement result regarding the relationship between the shift amount of the threshold voltage of the analog switch TFT and the operation time. The selection signal Vg is set to 20 V, and the load capacitance C is set to about 10 pF so as to be equal to the load capacitance of a standard liquid crystal panel. The operating frequency f is set to 320 kHz.

In the liquid crystal device of the present embodiment, an analog switch TFT divided into n blocks is provided to reduce the number of data drivers or the number of terminals.
Since the number is reduced to n, the time allowed for charging and discharging the pixel electrode is shorter than usual. For this reason, the operating frequency f is also increased. 10V amplitude corresponding to the input signal supplied to the analog switch TFT (that is, Vd =
When a square wave signal of 10 V) is applied, the shift characteristic of the threshold value is indicated by "G", and the amplitude of the 5 V amplitude (that is,
When a rectangular wave signal (Vd = 5V) is applied, the signal becomes as shown by "H".

When Vd = 10 V, the threshold voltage shifts by 1 V in about 200 hours. On the other hand, when the amplitude of the input signal applied to the source region of the analog switch TFT is 5 V, that is, when Vd = 5 V, 1
The shift amount of the threshold voltage can be maintained at 1 V or less until about 0000 hours.

If the shift amount of the threshold voltage is larger than 1 V, the amount of writing data to the pixel electrode becomes insufficient, that is, the potential of the pixel electrode cannot be set to a desired potential, and therefore, the contrast ratio decreases. Such a problem arises. In particular, for example, when the threshold voltage of the analog switch TFT is about 1 V, if the threshold voltage shifts by about 1 V to the minus side, the analog switch TFT enters the depletion mode, and the analog switch TFT turns off. Even in the state, current leaks, which leads to deterioration of display characteristics.

In order to ensure sufficient reliability of the liquid crystal device, the shift amount of the threshold voltage must be maintained at 1 V or less for at least about 1000 hours, and 1 V or less for about several thousand hours. Is desirable. In the case of Vd = 10V, the shift amount becomes larger than 1V in about 200 hours as shown in FIG.
This causes a problem in securing reliability. In the liquid crystal device of this embodiment, the amplitude of the input signal of the analog switch TFT is set to 5 V or less,
The electric field concentration at the end of the source region can be reduced. As a result, the shift amount of the threshold voltage can be kept at 1 V or less until about 10,000 hours, and the reliability can be secured while keeping a sufficient margin. Further, the amplitude of the input signal is 5 V
By setting as follows, the difference in the punch-through voltage of the analog switch TFT can be reduced, and the DC applied voltage to the liquid crystal can be reduced.

In FIG. 22, in order to properly compare with Vd = 10V, Vg = Vg = 5V.
The measurement is performed at 20V. However, Vd =
5 V, that is, when the amplitude of the input signal is 5 V, Vg
= 15V, the same write performance as Vd = 10V and Vg = 20V can be ensured. In this case, the shift amount of the threshold voltage is further reduced as compared with that shown by "H" in FIG. 22, and the reliability is improved. Further, in order to further improve the reliability, it is desirable that Vd = 3 V or less. It should be noted that Vd = 5V in "I" of FIG.
The measurement results at an operating frequency of 32 kHz are also shown for reference.

Next, in the liquid crystal device of this embodiment, the pixel T
It is desirable that the FT and the analog switch TFT be formed of polycrystalline silicon or single crystal silicon and be formed integrally on a glass substrate. Analog switch T
An input signal is applied to the FT, and display characteristics deteriorate unless charging / discharging of the pixel electrode is completed within a predetermined period. Therefore, it is necessary to reduce the on-resistance of the analog switch TFT.
In particular, when the number of data drivers is reduced by dividing the analog switch TFT into n blocks, the demand for reducing the on-resistance becomes more severe. However,
Amorphous silicon TFTs, that is, amorphous silicon TFTs, have very low mobility, and although they can be used for pixel TFTs, they cannot be used for analog switch TFTs because of the above-mentioned problem of on-resistance.

In the present embodiment, the pixel TFT and the analog switch TFT are formed of polycrystalline silicon or single crystal silicon, which has a much higher mobility than amorphous TFTs. Thereby, the pixel TFT and the analog switch TFT
In practice, it is possible to form a single unit on a glass substrate. By integrally forming the pixel TFT and the analog switch TFT on a glass substrate, the external dimensions of the liquid crystal device can be reduced, and the cost of the device can be reduced.

Next, a manufacturing method and a device structure in the case where a pixel TFT and an analog switch TFT are integrally formed will be described with reference to FIG. First, the glass substrate 13
Base insulating film 13 for preventing diffusion of impurities from zero
After depositing 2 on the glass substrate 130, a polycrystalline silicon thin film 134 is deposited. Improving the crystallinity of the polycrystalline silicon thin film 134 is necessary for increasing the field effect mobility. Therefore, a polycrystalline silicon thin film is recrystallized using laser annealing, a solid phase growth method, or the like, or an amorphous silicon thin film is crystallized to be polycrystalline silicon. After patterning the polycrystalline silicon film 134 into an island shape, a gate insulating film 136 is deposited.

Next, the gate electrode 13 is made of, for example, a metal.
After that, an impurity such as phosphorus ions is doped on the entire surface. Next, an interlayer insulating film (SiO ₂ ) 140 is formed, a signal line or the like is formed of a metal thin film 142 of, for example, aluminum (Al), a pixel electrode 144 is formed of a transparent conductive film such as ITO, and a passivation film 146 is formed. If formed, the pixel TFT is connected to the analog switch T
A substrate integrally formed with the FT is completed. The liquid crystal device is completed by subjecting the substrate to an orientation process, facing the opposite substrate 135, which has been similarly subjected to the orientation process, with a gap of several μm therebetween and sealing the liquid crystal L in the gap.

For example, as shown in FIG. 3, a display electrode 22 is formed on the surface of the counter substrate 135 on the liquid crystal L side, and the pad 2 of the wiring 24 extending from the display electrode 22 is formed.
5 is connected to a terminal from an external circuit. Also, the wiring 24
Is formed by a two-layer structure including a transparent conductive layer 70 and a low-resistance metal layer 72, as shown in FIG. The display electrode 22 is also formed as necessary, as shown in FIG. 6B, by a two-layer structure including a wide transparent conductive layer 70 and a narrow low-resistance metal layer 72.

The liquid crystal device 101 shown in FIG. 17 can be formed, for example, in the appearance shown in FIG. In FIG.
The portion indicated by the broken line is the display screen, that is, the active matrix area 160. The liquid crystal material is sandwiched between the color filter substrate 162 and the TFT substrate 164. Area 1
At 66, an analog switch TFT and its wiring are arranged.

The data driver 170 has a TAB (Tape Aut).
(Omated Bonding) Tape 168 is used. Then, the data driver 172 and the scanning driver 174 are similarly mounted using the TAB tape 168.

On the circuit board 176, the data driver 1
Wirings, capacitors, and the like for supplying signals to 70 and 172 and the scanning driver 174 are provided. In some cases, a control circuit for controlling the data driver and the scanning driver is also provided.

In the embodiment shown in FIG. 19, half of the analog switch TFTs are arranged above and below the active matrix area 160, respectively. Therefore, the M signal lines shown in FIG. 17 are wired in a so-called comb-like shape from both the upper and lower sides. The data driver and the scanning driver are mounted on the same side of a liquid crystal panel having a structure in which the color filter substrate 162 and the TFT substrate 164 are bonded to each other. With such a configuration, the liquid crystal device of the present embodiment can have a very small outer dimension L3, and therefore can be suitably used for portable devices such as a mobile phone and a portable electronic terminal.

As described above, in the liquid crystal device 101 of the present embodiment, in order to make the threshold voltage shift amount of the analog switch TFT appropriate, an input signal supplied to the source region of the analog switch TFT is used. Is desirably 5 V or less. However, in this case, the following problem occurs when a normal driving method is used.

FIG. 21 shows a normal drive waveform for performing the field inversion drive. Liquid crystal it is necessary to AC drive needs to be polarity inverted every predetermined period a signal V _S applied to the signal line around a predetermined electric potential V _C. Therefore the amplitude of V _S as shown in FIG. 21 is very wide. And since the conventional TN liquid crystal it is necessary to apply a voltage of about ± 5V, the amplitude of V _S is also required about 10V. Note that the potential Vcom to be applied to the counter electrode, in order to compensate for the penetration voltage produced when the pixel TFT is turned off, has a potential lower ΔV than the center potential V _C of V _S. Here, the relationship of the average value of ΔV = V _C −Vcom is established.

[0147] In the driving waveform shown in FIG. 21, it is necessary to increase the amplitude of _{V S} and about 10V. Therefore, it is necessary to increase the amplitude of the input signal of the analog switch TFT, and the amplitude of the input signal cannot be reduced to 5 V or less. Therefore, in the present embodiment, as shown in FIG. 20, driving is performed in which the polarity of the potential applied to the counter electrode with respect to the input signal is inverted every horizontal scanning period.
Common swing drive).

[0148] In Figure 21, although the polarity of _{V S} was then inverted every field around the _{V C,} the 1H common swing driving, the polarity of the Vcom is inverted every one horizontal scanning period, the _{V S} There is no need to perform polarity inversion. Therefore, it is possible to reduce the amplitude of V _S. This makes it possible to reduce the input signal of the analog switch TFT to 5 V or less while maintaining the display quality. Further, the data driver can be operated at a lower operating voltage, and can be formed by a manufacturing process with a withstand voltage of 5 V, so that the size, the power consumption, and the cost of the data driver can be reduced.

As described above, according to the 1H common swing drive,
The improvement of the reliability of the analog switch TFT and the low operation voltage of the data driver can be compatible. In FIG. 20,
To prevent the adverse effect of penetration voltage, thereby hold the relation of the average value of the average value -Vcom average value = V _S of [Delta] V.

As described above, in this embodiment, the stripe-shaped display electrodes 22 as shown in FIG. 3 are formed on the counter substrate 135 of FIG. The wiring 24 connected to the display electrode 22 has a laminated structure of a transparent conductive layer 70 and a metal layer 72 as shown in FIG. Therefore, the electric resistance of the wiring 24 can be reduced as compared with the case where the wiring 24 is formed only of the transparent conductive layer 70,
Therefore, the possibility that the display quality of the liquid crystal device is reduced due to the voltage drop in the wiring 24 is reduced. Further, since it is not necessary to increase the thickness of the transparent conductive layer 70 in order to reduce the electric resistance of the wiring 24, the transparent conductive layer of the display electrode 63 that is often formed simultaneously with the transparent conductive layer 70 of the wiring 24 is not necessary. The film thickness at 70 does not become unnecessarily thick. Therefore, the light transmittance of the display electrode 63 can be increased as compared with the case where the electric resistance of the wiring 24 is reduced only by increasing the thickness of the transparent conductive layer 70.

Further, the thickness of the transparent conductive layer 70 used for the display electrode 63 and the wiring 24 can be reduced as compared with the case where the electric resistance of the wiring 24 is reduced only by increasing the thickness of the transparent conductive layer 70. In addition, the time required for forming the counter substrate 2a, that is, the display device substrate can be reduced.

(Fifth Embodiment) FIGS. 8A, 8B, and 8C show the liquid crystal device 10 shown in FIG. 1, the liquid crystal device 1 shown in FIG. 15, the liquid crystal device 101 shown in FIG. 17, and the like. 1 shows an embodiment of an electronic device used as a device. FIG.
(A) shows a mobile phone 88 having a liquid crystal device 10 and the like above its front surface. FIG. 8B shows a wristwatch 92,
A liquid crystal device 10 and the like are provided as a display unit in the center of the front surface of the main body. FIG. 8C illustrates a portable information device 96 including a display unit including the liquid crystal device 10 and the like, and an input unit 98.

Each of the above-described electronic devices is, for example, a display information output source 86, as shown in FIG.
It is configured to include various circuits such as a display information processing circuit 87, a clock generation circuit 89, and the like, and a display signal generation unit 93 including a power supply circuit 91 for supplying power to those circuits. For example, in the case of the portable information device 96 shown in FIG. 8C, a display signal generated by the display signal generation unit 93 based on information input from the input unit 98 is supplied to the display unit. Thus, a display image is formed.

The electronic devices in which the liquid crystal device 10 and the like according to the present embodiment are incorporated include a mobile phone, a wristwatch,
Not limited to portable information devices, various electronic devices such as a notebook computer, an electronic organizer, a pager, a calculator, a POS terminal, an IC card, a mini disk player, and the like can be considered.

(Other Embodiments) The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and various modifications may be made within the scope of the invention described in the claims. Can be modified.

For example, in each of the above-described embodiments,
The example in which the transparent conductive layer was formed of ITO and the metal layer was formed of aluminum was shown. However, the material for forming the transparent conductive layer only needs to have high light transmittance and sufficient conductivity, and may be, for example, tin oxide or silver. Further, the transparent conductive layer may be a semi-transmissive film having a semi-transmissive function of performing both light transmission and light reflection. The material for forming the metal layer only needs to have sufficient conductivity, and may be, for example, chromium, copper, silver, or gold.

Further, in the liquid crystal panel of each of the above-described embodiments, a color filter may be formed on one inner surface of a pair of substrates to form a color display device. The color filter is preferably formed below the display electrode.

In each of the embodiments described above, the STN type liquid crystal panel is described as the liquid crystal panel. However, the liquid crystal panel is not limited to this, and TN
(Twisted Nematic) type, guest host type, phase transition type,
Various types of liquid crystal panels such as a bistable TN (Bi-stable Twisted Nematic) type and a ferroelectric type can be used. Further, the display electrode is not limited to a stripe shape, but may be a character shape such as an icon.

Further, in the embodiment shown in FIG.
The transmission type liquid crystal device has been exemplified. However, the present invention can be applied to a reflective display device. In such a liquid crystal device, a reflective plate is disposed on the back side without using a backlight unit, or one of the display electrodes is formed as a reflective electrode.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention or within the equivalent scope of the claims.

[0161]

As described above, according to the present invention, since the wiring has a laminated structure of the transparent conductive layer and the metal layer, the wiring can be formed as compared with the case where the wiring is formed only of the transparent conductive layer. Can be reduced in electric resistance. Therefore, in the liquid crystal device using the display device substrate of the present invention, the possibility that the display quality is deteriorated due to a voltage drop in the wiring is low.

Since it is not necessary to increase the thickness of the transparent conductive layer in order to reduce the electric resistance of the wiring, the film in the transparent conductive layer of the display electrode, which is often formed simultaneously with the transparent conductive layer of the wiring, is not necessary. The thickness is not increased more than necessary. Therefore, the light transmittance of the display electrode can be increased as compared with the case where the electric resistance of the wiring is reduced only by increasing the thickness of the transparent conductive layer.

Further, the thickness of the transparent conductive layer used for the display electrode and the wiring can be reduced as compared with the case where the electric resistance of the wiring is reduced only by increasing the thickness of the transparent conductive layer. Can be reduced in time required for the formation.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a liquid crystal device according to the present invention in an exploded state.

FIG. 2 is a sectional view showing a sectional structure of the liquid crystal device shown in FIG. 1 in an exploded state.

FIG. 3 is a plan view showing one panel substrate constituting the liquid crystal device shown in FIG.

FIG. 4 is a plan view showing another panel substrate constituting the liquid crystal device shown in FIG.

5 is an enlarged plan view showing one display electrode and wiring on the panel substrate shown in FIG. 4;

6A is a cross-sectional view illustrating a cross-sectional structure of a wiring according to line FF in FIG. 5, and FIG. 6B is a cross-sectional view illustrating a cross-sectional structure of a display electrode along line GG in FIG. is there.

FIGS. 7A to 7E are cross-sectional views illustrating a manufacturing process of the panel substrate by exemplifying a part of the panel substrate;

8A and 8B are diagrams showing an embodiment of an electronic device according to the present invention, wherein FIG. 8A shows a mobile phone, FIG. 8B shows a wristwatch, and FIG. 8C shows a mobile information device.

9 is an enlarged plan view showing a modification of one display electrode and wiring on the panel substrate shown in FIG. 4;

FIG. 10 is a cross-sectional view showing a cross-sectional structure of the display electrode according to line GG of FIG. 9;

FIG. 11 is a block diagram illustrating an example of an electric control system of the electronic device.

FIG. 12 is an exploded perspective view showing a main part of another embodiment of the liquid crystal device according to the present invention.

13 is a cross-sectional view illustrating a cross-sectional structure of a main part of the liquid crystal device of FIG.

FIG. 14 shows one TFD used in the liquid crystal device of FIG.
FIG.

15 is a perspective view showing an external shape of the liquid crystal device of FIG.

FIG. 16 is a plan view illustrating one of the display device substrates included in the liquid crystal device of FIG.

FIG. 17 is a circuit diagram showing a circuit structure of still another embodiment of the liquid crystal device according to the present invention.

18 is a cross-sectional view illustrating a cross-sectional structure of a main part of the liquid crystal device illustrated in FIG.

19 is a plan view showing an external shape of the liquid crystal device shown in FIG.

FIG. 20 illustrates a method 1H for driving the liquid crystal device illustrated in FIG.
FIG. 6 is a diagram illustrating a driving waveform for realizing the common swing driving method.

FIG. 21 is a diagram showing driving waveforms for realizing a field inversion driving method which is a general driving method of a TFT type active matrix liquid crystal device.

FIG. 22 is a graph showing the results of measurements performed to confirm the relationship between the shift amount of the threshold voltage and the operation time.

DESCRIPTION OF SYMBOLS 1 Liquid crystal device 2a, 2b substrate (display device substrate) 3 Sealing material 6a, 6b substrate 10 liquid crystal device 14 liquid crystal panel 20, 30, 80 panel substrate (display device substrate) 21, 31 substrate 22, 32, 82 Display electrode 24, 34, 36 Wiring 63 Display electrode 70 Transparent conductive layer 72 Metal layer 74 First photoresist film 76 Second photoresist film 82 Display electrode 84 Slit 88 Cellular phone (electronic device) 92 Watch (Electronic equipment) 96 Portable information equipment (Electronic equipment) L LCD

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/3205 H01L 49/02 49/02 21/88 A

Claims (14)

[Claims] 1. A display device substrate comprising: a plurality of display electrodes; and a plurality of wirings for applying a voltage to the plurality of display electrodes, wherein the wirings are formed of a transparent layer of the same layer as the display electrodes. A display device substrate, having a laminated structure of a transparent conductive layer made of a transparent conductive layer and a metal layer made of a metal having a lower resistance than the transparent conductive layer. 2. The display electrode according to claim 1, wherein the display electrode has a laminated structure of a transparent conductive layer made of a transparent conductive layer and a metal layer made of a metal having a lower resistance than the transparent conductive layer. Display device substrate. 3. The display device substrate according to claim 2, wherein a width of the metal layer in the display electrode is smaller than a width of the transparent conductive layer. 4. The display electrode according to claim 1, wherein the display electrode has a laminated structure of the transparent conductive layer and the metal layer, and the metal layer is partially opened in a part of the laminated structure. A substrate for a display device, comprising: 5. The display device according to claim 1, wherein the wiring is a wiring drawn from an end of the display electrode along a periphery of the substrate. Substrate. 6. A liquid crystal device having a liquid crystal sandwiched between a pair of substrates, wherein the display device substrate according to claim 1 is used for at least one of the pair of substrates. A liquid crystal device characterized by comprising: 7. A liquid crystal layer sandwiched between the display device substrate according to claim 4 and an opposing substrate opposed thereto,
A liquid crystal device having a transmission type display function using an opening of the metal layer as a light transmission part and a reflection type display function using a part of the metal layer as a light reflection part. 8. An electronic apparatus comprising the liquid crystal device according to claim 6 as display means. 9. The method of manufacturing a display device substrate according to claim 1, wherein the transparent conductive layer is formed on the substrate, and the transparent conductive layer is formed on the substrate. A method for manufacturing a display device substrate, comprising: a metal layer laminating step of laminating a metal layer on a layer; and an etching step of simultaneously etching the transparent conductive layer and the metal layer. 10. The method of manufacturing a display device substrate according to claim 1, wherein the transparent conductive layer is formed on the substrate, and the transparent conductive layer is formed on the substrate. A metal layer laminating step of laminating a metal layer on a layer; and a first patterning step of simultaneously etching and patterning the transparent conductive layer and the metal layer using a first photoresist film.
An etching step, forming a second photoresist film having a predetermined pattern by performing exposure and development of the first photoresist film, and etching and patterning only the metal layer using the second photoresist film. 2. A method for manufacturing a display device substrate, comprising: two etching steps. 11. The display device according to claim 10, wherein the metal layer in the display electrode is etched by the second etching step so as to be left only on an end of the transparent conductive layer. Method of manufacturing substrates. 12. The display device substrate according to claim 10, wherein the metal layer in the display electrode is etched so as to have an opening on the transparent conductive layer by the second etching step. Manufacturing method. 13. A liquid crystal device in which liquid crystal is sandwiched between a pair of display device substrates, wherein one of the display device substrates is formed with a plurality of pixel electrodes and each of the pixel electrodes. The other display device substrate includes a plurality of display electrodes arranged in a stripe shape facing the plurality of pixel electrodes, and a wiring connected to the display electrodes. The plurality of display electrodes include a transparent conductive layer, the wiring is a transparent conductive layer made of the same transparent conductive layer as the display electrode, and a lower resistance than the transparent conductive layer A liquid crystal device having a laminated structure with a metal layer made of metal. 14. A liquid crystal device in which liquid crystal is sandwiched between a pair of display device substrates, wherein one of the display device substrates is formed with a plurality of pixel electrodes and each of the pixel electrodes. The other display device substrate includes a plurality of display electrodes arranged in a stripe shape facing the plurality of pixel electrodes, and a wiring connected to the display electrodes. The plurality of display electrodes include a transparent conductive layer, the wiring is a transparent conductive layer made of the same transparent conductive layer as the display electrode, and a lower resistance than the transparent conductive layer A liquid crystal device having a laminated structure with a metal layer made of metal.