JP3242017B2 - Electrode substrate, method of manufacturing the same, liquid crystal element using the electrode substrate, and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode substrate having at least two types of electrodes, a method for manufacturing the same, a liquid crystal device using the electrode substrate, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, liquid crystal elements (hereinafter, referred to as "liquid crystal panels") for displaying information using liquid crystals have been used in various fields. First, an example of the structure of the liquid crystal panel will be briefly described with reference to FIG.

As shown in FIG. 1, the liquid crystal panel P ₁ has a pair of electrode substrates 1, 1 arranged so as to face each other.
These electrode substrates 1 and 1 are bonded together by a sealing material 2, and a liquid crystal 3 is held in an internal gap. Here, a ferroelectric liquid crystal panel using a ferroelectric liquid crystal as the liquid crystal 3 will be described as an example.

On the other hand, each electrode substrate 1 has a glass substrate 5, on the surface of which a transparent electrode 6 made of ITO (indium tin oxide) is formed. These transparent electrodes 6,.
It has a thickness of about 150 nm and is formed in a stripe shape by patterning (see FIG. 1B).
On the surface of these transparent electrodes 6, an insulating film 7 for preventing short circuit is formed by silicon oxide, titanium oxide or the like to a thickness of about 500 to 3000 °.
Further, an alignment control film 9 is formed on the surface thereof by a polyimide resin or the like.

Since the ferroelectric liquid crystal 3 generally uses chiral smectic liquid crystal (SmC *, SmH *), the upper and lower electrode substrates 1, 1 are less affected (the upper and lower electrode substrates 1, 1). intervals show orientation when etc.) spiral twisted in the liquid crystal molecular long axis direction in the very far beyond the 100 [mu] m, the cell thickness of the liquid crystal panel P _1,
By reducing the thickness to about 1 to 3 μm, such a twist in the major axis direction of liquid crystal molecules is eliminated (P213-P2).
34, N.M. A. CLARK etal, MCLC 19
83, Vol. 94).

By the way, such a liquid crystal panel P ₁
Since the transparent electrodes 6,..., 6,... Opposing each other are driven by applying a voltage, the liquid crystal 3 interposed between the transparent electrodes 6,. , But
The resistance value of the transparent electrodes 6,.
Ω, 200 × 10 ^{-8 to} 4000 × 10 ^-8 Ω in volume resistance
m and high. Therefore, propagation delay of the voltage waveform in the transparent electrode 6 is apt to occur, which has been an obstacle in achieving higher definition and larger area of the liquid crystal panel. In the case of a ferroelectric liquid crystal element, such a problem occurs when the liquid crystal thickness is 1 to 1.
This was particularly noticeable because the thickness was 2 μm, which is thinner than a TN type liquid crystal element.

Therefore, as a method of eliminating such a delay in the voltage waveform, a method of increasing the thickness of the transparent electrodes 6,... Is considered. However, according to this method, it takes time to form the transparent electrodes 6,. In addition, problems such as poor adhesion of the transparent electrodes 6,... To the substrate occur, and further, the transmittance is reduced, the transparent electrodes 6,... Are visually recognized, and the display quality of the liquid crystal panel is deteriorated. was there.

As another method for eliminating the delay of the voltage waveform, Cr (15 × 10 ⁻⁸ Ωm) or Mo (6 × 10 ⁻⁸ Ωm) is used.
There is a method of forming a low-resistance metal electrode such as Ωm) on the surface of the transparent electrode 6 (the surface on the side where the liquid crystal 3 is injected), but the metal electrode may be thickened for the following reasons. However, there is a limit to avoid delay of the voltage waveform. That is, the metal electrodes are arranged to face each other with the liquid crystal interposed therebetween, but the thickness of the metal electrodes is limited by the gap between the substrates.
Specifically, when the substrate gap is 1.1 μm, the thickness of the metal electrode cannot exceed 550 nm, and it is actually necessary to form an insulating film or the like on the surface of the metal electrode.
The metal electrodes were quite thin.

In the case where such a metal electrode is formed, similarly to the case described with reference to FIG. 1, the metal electrode and the transparent electrode are covered with the alignment control film 9, and the liquid crystal molecules are coated with the alignment control film 9. They need to be arranged in a certain order. However, in such a case, unevenness due to the metal electrode occurs in the alignment control film 9. As the metal electrode becomes thicker, the irregularities become larger. Accordingly, there is a problem that an optical difference occurs between the concave portion and the convex portion, and the display quality of the liquid crystal panel is deteriorated. There is also a problem that the electric field responsiveness of the liquid crystal changes between the concave portion and the convex portion, so that crosstalk easily occurs. Further, there is a problem that the rubbing treatment of the alignment control film 9 cannot be performed uniformly due to the unevenness due to the metal electrode, and the alignment state is not uniform, and optical differences and crosstalk also occur. Such a problem was remarkable in a liquid crystal panel in which the pixel size was reduced for higher definition. Therefore, in order to avoid such a problem, the thickness of the metal electrode needs to be less than a predetermined value (actually, 250 nm or less).

Therefore, as another method for eliminating such a delay of the voltage waveform, a low-resistance metal electrode such as Cr or Mo is provided on the back surface (substrate side surface) instead of the front surface of the transparent electrodes 6,. The forming method is disclosed in JP-A-2-63019, JP-A-5-158182 and the like.

[0011] Figure 2 is a sectional view showing an example of the structure of a liquid crystal panel using the method, the liquid crystal panel P ₂
Has a pair of electrode substrates 10, 10 arranged substantially in parallel, as shown in FIG. This electrode substrate 10
Has a transparent glass substrate (substrate) 11 as shown in detail in FIG. 1B, and a metal electrode (first electrode) 12 having a thickness of about 1 μm, Are formed in stripes. These metal electrodes 12,... Are arranged with a predetermined gap therebetween, and a gap between these many metal electrodes 12,. The resin 13 forms one surface together with the metal electrodes 12,. On the surface formed by the metal electrodes 12,... And the resin 13, a large number of transparent electrodes (second electrodes) 6, also in the form of stripes, are formed. And an orientation control film 9. The transparent electrodes 6,... Correspond to the respective metal electrodes 12,.
Are arranged along each metal electrode 12,.

The pair of electrode substrates 10, 10
Are bonded by a sealing material 2, and a liquid crystal 3 is injected into the gap.

[0013] Next, the manufacturing method of the liquid crystal panel P _2, will be explained with reference to FIG. 3 (a) ~ (f) . (First Electrode Forming Step) First, on the surface of the glass substrate 11,
A thick metal layer 14 is formed by sputtering or the like.
(a)), the metal layer 14 is patterned by photolithography to form a striped metal electrode (first metal layer).
(See FIG. 3 (b). Hereinafter, a structure as shown in FIG. 3 (b) will be referred to as a "wiring board 15," and the metal electrodes 12,. The surface on the formed side is referred to as “wiring surface 15a”).

Then, the wiring surface 15a of the glass substrate 11 is subjected to a silane coupling treatment to ensure the adhesion between the glass substrate 11 and a UV curing resin 13 provided later. (Resin Supplying Step) In this step, a predetermined amount of UV curable resin 13L is dropped on a smooth surface of the mold glass 16 using a dispenser or other device (here, reference numeral “13L” indicates a state before curing). Liquid resin.
The cured resin is represented by the symbol “13S”, and when no particular distinction is required, it is simply referred to as “resin 13”.) The surface of the mold glass 16 on which the resin 13L is dropped and the wiring surface 15a of the wiring board 15 are The resin 13L is sandwiched between the mold glass 16 and the wiring board 15 (hereinafter, the structure constituted by the wiring board 15 and the mold glass 16 is referred to as a "pressurized body 17"). ").

Accordingly, the wiring surface 15 of the wiring board 15
a, ie, the metal electrodes 12,...
L will be filled. (Resin Hardening Step) Then, the pressurized body 17 is pressed by a press (not shown). In this pressurized state, the metal electrode 1
2 and the resin 13L supplied to the gap between the metal electrodes 12 are in contact with the smooth surface of the mold glass 16,
The gap between the metal electrodes 12,... Is filled with the UV curable resin 13L, and the liquid UV curable resin 13L and the metal electrodes 12,.

Then, in this pressurized state, the UV curable resin 13L of the pressurized body 17 is irradiated with ultraviolet light L from the glass substrate 11 side.
(Hereinafter, referred to as “UV light L”) to cure the resin 13L (see FIG. 4D). (Peeling Step) Next, the pressed body 17 is taken out of the press machine, and the mold glass 16 is peeled using a peeling device (not shown) (see FIG. 3E). (Second Electrode Forming Step) Thereafter, a large number of transparent electrodes 6,... Are formed so as to be in contact with the respective metal electrodes 12,. (Other steps) In addition, the electrode substrate 10 prepared by forming an insulating film 7 and an alignment control film 9, further a liquid crystal panel P ₂ by injecting liquid crystal 3 with bonding the pair of electrode substrates 10 and 10 create.

[0017]

The silane coupling treatment for improving the adhesion to the resin 13 is performed only on the surface of the glass substrate 11 and not on the surface of the mold glass 16. In the resin curing step described above, the adhesion between the resin 13L and the mold glass 16 is
Although it is weaker than the adhesion between the 3L-glass substrate 11, it has some adhesion. On the other hand, the above-mentioned UV curable resin 13L generally has a property of shrinking when irradiated with UV light L and cured. Therefore, UV curing resin 1
No. 3 is that it is partially peeled off from the surface of the mold glass 16 due to the shrinkage (in other words, a partially adhered portion remains), and the peeled portion is not restricted at all. , The shrinkage partially progressed, and as a result, dents 19,... (Hereinafter referred to as “wrinkle-like sinks 19,. FIG. 4 shows wrinkled sink marks 1
It is a figure which shows a mode of generation | occurrence | production of 9, ..., (a) is resin 13L
FIG. 3B is a view showing a state before the resin 13 is cured, FIG. 4B is a view showing a state after the resin 13 is cured, and FIG.

Therefore, when a liquid crystal panel is manufactured using such an electrode substrate 10, the alignment control film 9 in the surface of the transparent electrodes 6,... And in the effective optical modulation region (display region in the case of a display element) is formed. The surface of the liquid crystal 3 is also not smooth, and as a result, the alignment state of the liquid crystal 3 is not uniform, or the electric field is concentrated due to the local narrowing of the cell gap. There is a problem that unevenness occurs and image quality is reduced.

The permissible range of the unevenness due to the metal electrode itself is about 250 nm or less. However, in the effective optical modulation region, the above-described problem occurs even if the unevenness is 250 nm or less. This is because the metal electrode portion is shielded from light, whereas the effective optical modulation area is not literally shielded from light.

In the method described above, the metal electrodes 12,.
In order to ensure conductivity between the metal electrodes 12 and the transparent electrodes 6 in the resin curing step,
It is necessary to remove L, but in many cases, merely pressing the surface of the metal electrodes 12,... With the mold glass 16 does not sufficiently remove the resin, and the resin 13L remains on the electrode surface. In such a case, the contact resistance between the metal electrodes 12,... And the transparent electrodes 6,... Becomes large, causing a problem of delay of the voltage waveform, and a problem that high-definition display cannot be performed.

Accordingly, an object of the present invention is to provide an electrode substrate in which wrinkle-like sink marks do not occur in the resin and the surface of the second electrode is substantially smooth at least in the effective optical modulation region, and a method for manufacturing the electrode substrate. It is assumed that.

Another object of the present invention is to provide an electrode substrate and a method for manufacturing the electrode substrate, which prevent the occurrence of unevenness in optical state and crosstalk when used in a liquid crystal device.

Further, the present invention provides an electrode substrate for improving the contact state between the first electrode and the second electrode and preventing a delay of a driving waveform when used in a liquid crystal element, and a method for manufacturing the electrode substrate. The purpose is to do so.

Still another object of the present invention is to provide a liquid crystal device capable of coping with a large area and a high definition.

Another object of the present invention is to provide a liquid crystal element having excellent display quality.

[0026]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has a light-transmitting substrate, a plurality of first electrodes formed on the light-transmitting substrate, and a plurality of first electrodes. In an electrode substrate including a resin filled in a gap between the first electrodes and a plurality of second electrodes arranged so as to be in contact with the respective first electrodes, the thickness of the first electrodes is h ( n
m), and when the curing shrinkage of the resin is α (%), the surface roughness d (nm) of the first electrode is

[0027]

[Formula 5] d ≧ α · h / 1000.

In this case, it is preferable that the first electrode is a metal electrode and the same signal is applied to the first electrode and the second electrode. Further, the second electrode may be a transparent electrode. Further, the second electrode is formed by an ITO film.
You may do so.

Further, in the gap between the plurality of first electrodes,
A color filter arranged with the resin may be provided.

On the other hand, in the method of manufacturing an electrode substrate according to the present invention, a first electrode forming step of forming a plurality of first electrodes on a light-transmitting substrate, and filling a gap between the plurality of first electrodes with a resin. A resin supplying step, a resin curing step of curing the filled resin, and a second electrode forming step of forming a plurality of second electrodes so as to contact the first electrodes,
When the surface roughness d (nm) of the first electrode formed in the first electrode forming step is h (nm), the curing shrinkage of the resin is α (%), To

[0031]

[Formula 6] d ≧ α · h / 1000.

In this case, it is preferable that in the resin curing step, after the first electrode and the resin are pressed through a smooth plate-like member, the resin is cured. Further, the resin may be a resin that is cured by irradiating ultraviolet rays, and the resin may be irradiated with ultraviolet rays in the resin curing step.

A color filter forming step of forming a color filter in a gap between the plurality of first electrodes may be performed between the first electrode step and the resin supply step.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same parts as those shown in FIG.

First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 5 is a cross-sectional view showing the structure of the liquid crystal panel P _{3 according} to the present embodiment. As shown in FIG. 5A, the liquid crystal panel P ₃ has a pair of substantially parallel arrangements. The electrode substrate 20 is provided. Then, the electrode substrate 20 is
As shown in detail in (b), a transparent glass substrate (substrate) 11
On the surface of the glass substrate 11, a large number of metal electrodes (first electrodes) 22,... Are formed in a stripe shape. These metal electrodes 22,... Are arranged with a predetermined gap therebetween, and the gap is filled with a UV curable resin 13S. ing. On the surface, a large number of transparent electrodes (second electrodes) 6, also in the form of stripes, are provided.
Are formed, and an insulating film 7 and an orientation control film 9 are formed on the surface thereof. The transparent electrodes 6,... Are in contact with the respective metal electrodes 22,.
And the same signal is applied to these electrodes 6,... And 22,.

The pair of electrode substrates 20 are adhered to each other by the sealing material 2, and the gap between them is a liquid crystal 3.
Has been injected.

In the present embodiment, the size of the glass substrate 11 is 300 × 340 mm, and the transparent electrodes 6,... Are formed of an ITO film.

Further, the UV curable resin 13 has a curing shrinkage rate α as a resin which is cured by irradiating UV light.
Uses 10% of an acrylic monomer resin (manufactured by Nippon Kayaku Co., Ltd.) (α is about 6 to 10% for an acrylic resin and about 2 to 5% for an epoxy resin). Further, the metal electrodes 22 are formed of Al, and the thickness h is set to 2000.
nm, and the average surface roughness d is 20 nm.

That is, in this embodiment, the curing shrinkage of the UV curable resin 13 is set to α (%), and the metal electrodes 22,.
Are defined as h (nm), the surface roughness d (nm) of the metal electrodes 22,.

[0041]

[Formula 7] d ≧ α · h / 1000 = 10 · 2000/1000 = 20.

In this embodiment, the metal electrode 2
The average surface roughness d of 2,... Is preferably 200 nm or less from the viewpoint of uniforming the cell gap.

[0043] Next, a manufacturing method of the liquid crystal panel P _3, will be described with reference to FIG. (First Electrode Forming Step) First, an Al layer 23 was formed on the entire surface of the glass substrate 11 (see FIG. 6A). The Al layer 23 is formed by sputtering, and the thickness h of the Al layer 23 is
Is 2000 nm, and the average surface roughness d of the Al layer 23 is 2
It was set to 0 nm.

Here, an RF sputtering apparatus (model number 705 manufactured by Nidec Anelva Co., Ltd.) was used as the sputtering apparatus.
The substrate temperature during sputtering was set to 140 ° C., the sputtering time was set to 680 seconds, and Ar gas (2
(00 sccm, 3 mtorr) and the RF power density was 6 W / cm ² .

The average surface roughness d of the Al layer 23 was confirmed by a surface roughness meter (α-step 500 manufactured by Tencor Instruments) as follows. That is, the measurement length was set to 500 μm, and the height difference between the highest point and the lowest point of the Al layer 23 was measured at nine locations using a surface roughness meter, and the average was taken to be the average surface roughness d.

Thereafter, a photolithography method is performed,
The Al layer 23 was etched with a mixed acid to form striped metal electrodes (first electrodes) 22,... (See FIG. 3B. Hereinafter, a structure as shown in FIG. The surface on the side of the wiring substrate 25 on which the metal electrodes 22,... Are formed is referred to as a "wiring surface 25a." The width of the metal electrode 22 was 16 μm, and the pitch was 90 μm.

Further, the wiring substrate 25 is rotated at a rotation speed of 2000 rpm, and an adhesion enhancer (A-17 manufactured by Nippon Unicar Co., Ltd., which is a silane coupling agent) is applied to the wiring surface 25a.
4 was diluted to 5% with isopropyl alcohol), and the reinforcing agent was spin-coated on the substrate surface, and then baked at a temperature of 100 ° C. (Resin Supply Step) In this step, a liquid UV curable resin 13L is dropped on the wiring surface 25a of the wiring board 25, and FIG.
As shown in (c), the wiring surface 25a and the mold glass 16 are slowly brought into contact with each other so as not to entrap air bubbles, and are allowed to stand.
L (hereinafter, the structure shown in FIG. 6C is referred to as a “pressurized body 27”).

Thus, the wiring surface 25 of the wiring board 25
a, ie, the metal electrodes 22,.
L is filled, and the thickness of the resin 13L at this time is equal to the thickness h of the metal electrodes 22,. (Resin curing step) Then, when the pressed body 27 is pressed by a press (not shown), the surface of the metal electrodes 22,.
The resin 13L supplied to the gaps between the metal electrodes 22,... Is pressed through the smooth mold glass 16.

By the pressurization by the mold glass 16, the resin 13L is removed from the surfaces (at least the convex portions) of the metal electrodes 22,.

Then, after the pressurized body 27 is pressurized, U
When UV light L is applied to the V-cured resin 13L, the resin 13L
Are cured and shrink when cured. (Release Step) Then, when the curing of the resin 13 is completed, the mold glass 16 is peeled (see FIG. 3E). (Second Electrode Forming Step) Next, a number of transparent electrodes 6,... Are formed so as to be in contact with the respective metal electrodes 22,.
(f)). (Other steps) In addition, the transparent electrode 6, to form a surface on the insulating film 7 and an alignment control film 9 ... etc., to create a liquid crystal panel P _3.

Next, the effect of this embodiment will be described.

According to the present embodiment, in the resin curing step, the UV curable resin 13 that is cured and shrunk is replaced with the mold glass 16.
The wrinkle-like sink is prevented without being partially peeled off from the surface, and uniform sink occurs. This allows U
A substantially smooth surface is formed by the V-cured resin 13S, and the surfaces of the transparent electrodes 6,... Formed on the surface are also substantially smooth. Therefore, the alignment state of the liquid crystal 3 becomes uniform in the effective optical modulation region, and there is no unevenness in the optical state, no crosstalk or uneven driving, and the image quality is also improved. Here, as shown in FIG. 5 (b), irregularities remain on the surfaces of the metal electrodes 22,..., But the metal electrodes do not transmit light, so that they do not affect the image quality.

Further, according to the present embodiment, the metal electrodes 22,
Are set to 20 nm. Therefore, the metal electrodes 22,
, Even if the resin 13L is not completely removed from the surface of the metal electrodes 22, the projections on the surfaces of the metal electrodes 22,. As a result, the metal electrodes 22,.
And the transparent electrodes 6,... Are uniformly maintained over the entire surface of the electrode substrate, and the transparent electrodes 6,.
Are reduced. The present inventor has proposed transparent electrodes 6,.
When the resistance value (resistance value per 60 mm) of the metal electrodes 22,... Was measured, it was confirmed that the resistance was uniform and low at 50Ω over the entire substrate.

[0054] By using such a low-resistance electrode substrate in the liquid crystal panel P _3, latency issues of the voltage waveform at the time of the liquid crystal panel driving is resolved, also eliminates unevenness and crosstalk problems optical state As a result, it is possible to obtain a liquid crystal panel P ₃ capable of coping with a large area and high definition.

Further, in the present embodiment, it is not necessary to form the transparent electrodes 6 thick in order to eliminate the delay of the voltage waveform. Thus, the transparent electrode 6, without even the electrode from being recognized ... lowered transmittance, it is possible to improve the display quality of the liquid crystal panel P _3. Further, the film formation time of the transparent electrodes 6,... Is shortened, and the adhesion of the transparent electrodes 6,.

On the other hand, these metal electrodes 22,... Are formed on the back side (substrate side) of the transparent electrodes 6,.
Since a substantially smooth surface is formed together with the UV curable resin 13 (irregularities occur due to the shrinkage of the resin), even if these metal electrodes 22,... Are formed thickly, the surface of the alignment control film 9 has almost no irregularities. Does not occur. Then, the metal electrodes 22,.
Is formed, the problem of the delay of the voltage waveform is solved, and the surface of the alignment control film 9 becomes almost smooth, so that there is no concern about the occurrence of optical difference and crosstalk as described in the conventional example. . Further, the rubbing treatment can be performed uniformly, and the alignment state of the liquid crystal can be made uniform.

Next, a second embodiment according to the present invention will be described with reference to FIG.
An example will be described.

FIG. 7 is a sectional view showing the structure of the electrode substrate 30 according to the present embodiment. The electrode substrate 30 is arranged so as to be in contact with the gap between the metal electrodes 22 and the glass substrate 11. Are provided. The other configuration is the same as that described in the first embodiment.

The electrode substrate 30 is manufactured through a first electrode forming step, a color filter forming step, a resin supplying step, a resin curing step, a peeling step, a second electrode forming step, and the like. In the color filter forming step, a solution in which a pigment is dispersed in a photosensitive resin is applied by a roll coater, selectively exposed and developed, and etched to form color filters 31. Then, in the resin supply step, the resin 13L is supplied to the concave portion formed by the color filter 31 and the metal electrode 22. The other steps are the same as those described in the first embodiment.

Next, the effect of this embodiment will be described.

According to this embodiment, the same effects as those of the first embodiment can be obtained, and a liquid crystal panel having excellent color display quality can be obtained.

In the above-described embodiment, a sputtering method is used as a method for forming a metal film having a predetermined roughness. However, the method is not limited to the sputtering method. May be. Further, in the above-described embodiment, the substrate heating temperature during film formation was set to 140 ° C.
° C, but in the range of 180 to 300 ° C, preferably 10
The temperature may be in the range of 0 to 250 ° C., and can be appropriately set according to the required surface roughness. Further, the uppermost layer may be selectively etched by using a metal film as a multilayer structure.

In order to confirm the effect of this embodiment, the present inventors examined the occurrence of wrinkle-like sink marks by changing the surface roughness d and the thickness h of the metal electrodes 22,.
It was confirmed that wrinkle-like sinks did not occur when satisfying the above relationship. The results are shown in Table 1 (note that the symbol “○” in the table indicates that wrinkle-like sink marks did not occur, and the symbol “X” indicates that wrinkle-like sink marks occurred). Table 2 shows the film forming conditions for each metal electrode.

In the present embodiment, the occurrence of wrinkle-like sink marks was inspected by a defect inspection apparatus (manufactured by Admon Science) as follows. That is, the inspection is performed on the effective optical modulation area, but an image of a portion without wrinkle-like sink is stored in advance as a reference image, and CC
Enlarged image (50 to 2) of the inspection unit by the D image sensor
Then, the presence / absence of a shadow is determined by comparing the read image with the above-described reference image by image processing. If even one shadow is found in the effective optical modulation area, it is evaluated that “wrinkle-like sink marks have occurred”. In addition, the concave portion (wrinkle-like sink mark) that can be found by the present apparatus has a depth of 50 nm or more.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

As described above, according to the present invention,
In the step of manufacturing the electrode substrate, a resin is filled in a gap between the plurality of first electrodes by a thickness of the electrodes. Then, after the first electrode and the resin are pressed through a smooth plate-like member, the resin is cured. When the thickness of the first electrode is h (nm) and the curing shrinkage of the resin is α (%), the surface roughness d (nm) of the first electrode is

[0068]

[Formula 8] By setting d ≧ α · h / 1000, the resin does not partly peel off from the smooth plate-like member due to its curing shrinkage, and wrinkle-like sink marks do not occur. Is prevented. Thereby, the surface of the second electrode in the effective optical modulation region becomes substantially smooth.
Therefore, when this electrode substrate is used for a liquid crystal element,
The alignment state of the liquid crystal becomes uniform, and there is no unevenness in optical state or crosstalk, and the image quality is improved.

On the other hand, the surface roughness d (nm) of the first electrode
Is set to a predetermined value or more. Therefore, even if the resin is not completely removed from the surface of the first electrode by the pressurization using the smooth plate-like member as described above, at least the protrusion on the surface of the first electrode protrudes from the resin. Becomes Thereby, the contact state between the first electrode and the second electrode is uniformly maintained over the entire surface of the electrode substrate. When this electrode substrate is used for a liquid crystal element, the problem of voltage waveform delay during driving is solved, and the problems of optical state unevenness and crosstalk are also solved. As a result, a large area and high definition are achieved. Thus, a liquid crystal element that can cope with the development can be obtained.

On the other hand, when the first electrode is a low-resistance metal electrode, the resistance of the first electrode and the second electrode becomes low, and when a voltage having a predetermined waveform is applied to these electrodes. Is solved.
When this electrode substrate is used for a liquid crystal element, the problems of optical state unevenness and crosstalk are also eliminated, and as a result, a liquid crystal element that can cope with a large area and high definition can be obtained.

On the other hand, when the first electrode is a low-resistance metal electrode as described above, it is not necessary to form the high-resistance second electrode thick. Therefore, when this electrode substrate is used for a transmission type liquid crystal element, the display quality of the liquid crystal element can be improved without the transmittance of the second electrode being lowered and the electrode being recognized. Further, the film formation time of the second electrode is reduced, and the adhesion of the second electrode to the first electrode is also ensured.

On the other hand, by forming the first electrode on the substrate and filling the gap between the first electrodes with a resin, a substantially smooth surface is formed by the first electrode and the resin. For this reason, even if the first electrode is formed thick,
No noticeable unevenness occurs on the surface of the second electrode. Therefore, the problem of the delay of the voltage waveform is solved by forming the first electrode thick. Further, even when this electrode substrate is used for a liquid crystal element, the alignment state of the liquid crystal can be made uniform without concern about optical differences and occurrence of crosstalk.

Note that these effects can be obtained even if the second electrode is a transparent electrode or if the second electrode is formed of an ITO film.

On the other hand, the method of manufacturing the electrode substrate includes a first electrode forming step of forming a plurality of first electrodes on the substrate, and filling a gap between the plurality of first electrodes with a resin corresponding to the thickness of the electrodes. A resin supplying step, a resin curing step of curing the filled resin, and a second electrode forming step of forming a plurality of second electrodes so as to contact the first electrodes, and The surface roughness d (nm) of the first electrode formed in the first electrode forming step is determined by the thickness h (n) of the first electrode.
m) and the curing shrinkage of the resin is α (%),

[0075]

In the case where d ≧ α · h / 1000, the first electrode and the resin are pressed through a smooth plate-like member, and the resin is cured after the pressing. This prevents the resin from being partially peeled off from the smooth plate-like member due to its curing shrinkage, thereby preventing the occurrence of wrinkled sink marks. As a result, a substantially smooth surface is formed by the first electrode and the resin, and the surface of the second electrode in the effective optical modulation region becomes smooth. Therefore, by the method for manufacturing an electrode substrate according to the present invention, an electrode substrate suitable for a liquid crystal element can be obtained. When a liquid crystal element is manufactured using such an electrode substrate, the orientation of liquid crystal in the liquid crystal element is improved. The state becomes uniform, and nonuniformity of optical state and crosstalk do not occur, and the image quality becomes good.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing a general structure of a liquid crystal panel, and FIG. 1B is a diagram for explaining a shape of a transparent electrode.

2A is a cross-sectional view for explaining another conventional structure of a liquid crystal panel, and FIG. 2B is a detailed cross-sectional view showing a structure of an electrode substrate.

FIG. 3 is a view for explaining a conventional method for manufacturing an electrode substrate.

FIG. 4 is a diagram illustrating a problem in a conventional electrode substrate.

5A is a cross-sectional view for explaining a structure of a liquid crystal panel as one embodiment of the present invention, and FIG. 5B is a detailed cross-sectional view showing a structure of an electrode substrate.

FIG. 6 is a diagram illustrating a method for manufacturing an electrode substrate.

FIG. 7 is a sectional view for explaining the structure of an electrode substrate according to a second embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 2 sealing material 3 liquid crystal 6, transparent electrode (second electrode) 7 insulating film 9 alignment control film 11 glass substrate (translucent substrate) 13, 13L, 13S UV curing resin (resin) 16 type glass (smooth plate shape) member) 20 electrode substrate 22, ... metal electrode (first electrode) 23 metal layer 25 wiring board 27 to be pressure body 30 the electrode substrate 31, ... color filter P ₃ LCD panels

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Haruo Tomino 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-2-63019 (JP, A) JP-A-4 -55823 (JP, A) JP-A-6-347810 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1343

Claims (11)

(57) [Claims] A light-transmitting substrate; a plurality of first electrodes formed on the light-transmitting substrate; a resin filled in a gap between the plurality of first electrodes; A plurality of second electrodes arranged so as to be in contact with each other, wherein the thickness of the first electrode is h (nm) and the curing shrinkage of the resin is α (%). An electrode substrate, wherein the surface roughness d (nm) of the first electrode satisfies the following equation: d ≧ α · h / 1000 2. The electrode substrate according to claim 1, wherein the first electrode is a metal electrode, and the same signal is applied to the first electrode and the second electrode. 3. The electrode substrate according to claim 1, wherein the second electrode is a transparent electrode. 4. The electrode substrate according to claim 1, wherein said second electrode is formed of an ITO film. 5. The electrode substrate according to claim 1, further comprising: a color filter disposed together with the resin in a gap between the plurality of first electrodes. 6. A first electrode forming step of forming a plurality of first electrodes on a translucent substrate, a resin supplying step of filling a resin between the plurality of first electrodes, and a step of filling the filled resin. A resin curing step of curing, and a second electrode forming step of forming a plurality of second electrodes so as to contact the first electrodes,
The surface roughness d (nm) of the first electrode formed in the first electrode forming step, the thickness of the first electrode is h (nm), and the curing shrinkage of the resin. A method for producing an electrode substrate, characterized in that when the ratio is α (%), d ≧ α · h / 1000. 7. In the resin curing step, after the first electrode and the resin are pressed through a smooth plate-like member,
The method for manufacturing an electrode substrate according to claim 6, wherein the resin is cured. 8. The method for manufacturing an electrode substrate according to claim 7, wherein the resin is a resin that is cured by irradiating ultraviolet rays, and the resin is irradiated with ultraviolet rays in the resin curing step. 9. A color filter forming step of forming a color filter in a gap between the plurality of first electrodes between the first electrode step and the resin supply step. Item 7. The method for manufacturing an electrode substrate according to Item 6. 10. A liquid crystal element having a liquid crystal sandwiched between a pair of electrode substrates, the electrode substrate comprising: a light-transmitting substrate; a plurality of first electrodes formed on the light-transmitting substrate; A resin filled in a gap between the plurality of first electrodes; and a plurality of second electrodes arranged so as to be in contact with the respective first electrodes, and a thickness h (nm) of the first electrodes is provided. ), The curing shrinkage ratio α (%) of the resin, and the surface roughness d (nm) of the first electrode satisfy the following expression: d ≧ α · h / 1000. 11. A step of forming a plurality of first electrodes on a light transmitting substrate, a step of filling a gap between the plurality of first electrodes with a resin, and a step of curing the filled resin.
Forming a plurality of second electrodes so as to be in contact with each of the first electrodes, wherein the thickness h (nm) of the first electrodes and the cure shrinkage of the resin α (%), surface roughness d (nm) of the first electrode
Satisfies the following formula: d ≧ α · h / 1000.