JP2000111929A - Liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent disconnection of transparent electrodes, caused by the compression with a foreign matter, even if the foreign matter was mixed in the space between substrates in the sticking process of the substrates of the production step. SOLUTION: Transparent electrodes 2a, 2b are each covered with metal electrodes 4a, 4b. When the width of the transparent electrodes 2a, 2b are set to be T1 and the width of the metal electrodes 4a, 4b are set to be T2, T1 is adjusted to be not exceeding 50 μm and T2 is adjusted to be not less than 0.15×T1 at the narrow part of the width of the transparent electrodes 2a, 2b so that at least 15% of the surfaces of the transparent electrodes 2a, 2b are covered by the metal electrodes 4a, 4b. Thereby, even if the foreign matter was mixed in the space between substrates in the sticking process of the substrates of the production step, the foreign matter is accepted with the metal electrodes 4a, 4b and the formation of clack in or disconnection of the transparent electrodes 2a, 2b can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a liquid crystal device having a liquid crystal and electrodes for driving the liquid crystal.

[0002]

2. Description of the Related Art Conventionally, liquid crystal panels (liquid crystal elements) for displaying various information by using liquid crystals have been used in various fields, but in recent years, resolution, contrast, reliability and response speed have been high. There is a demand for a liquid crystal panel that can display multi-tone images quickly and can display colors.

One type of such a liquid crystal panel is an active matrix type, in which a TFT is provided for each pixel.
The liquid crystal is driven by providing such a switching element.

Another type of liquid crystal panel is a simple matrix type. This type of liquid crystal panel P ₁
As shown in FIG. 1, a pair of glass substrates 1a and 1b arranged at a predetermined distance from each other are provided, and the surface of each of the glass substrates 1a and 1b is made of ITO (indium.
The transparent electrodes 2a and 2b made of tin oxide) are formed in a stripe shape. Further, metal electrodes 4a and 4b made of aluminum or copper are formed so as to cover a part of the transparent electrodes 2a and 2b, and further, alignment films 6a and 6b are formed. In the gap between the pair of glass substrates 1a and 1b, a spacer 7 is arranged to define a gap between the substrates, and the liquid crystal 3 is further interposed therebetween. In addition, as shown in FIG. 2, the above-mentioned transparent electrodes 2a and 2b are arranged so as to be orthogonal to each other to form a matrix electrode.

[0005] In the production of the liquid crystal panel P ₁ is * each glass substrate 1a, on the surface 1b, the transparent electrode 2a by a sputtering method or a photolithography method, 2b is formed, and * Metal electrodes 4a, 4b Ya After the alignment films 6a and 6b are formed, * the pair of glass substrates 1a and 1b are attached to each other, and the liquid crystal 3 is injected into the gap between the substrates.

[0006] The liquid crystal panel P _1, since it is produced as compared with the active matrix type is simple, its application to a high-definition liquid crystal panels on a large screen is expected. Further, the metal electrodes 4a and 4b lower the wiring resistance to prevent a delay in the voltage waveform in a large-screen liquid crystal panel, and thereby provide uniform switching characteristics of liquid crystal molecules over the entire display area. Secured.

[0007]

[SUMMARY OF THE INVENTION Incidentally, in the case of the liquid crystal panel P ₁ of the simple matrix type as described above, the transparent electrode 2a by properly photolithography without causing disconnection, 2
Even if b is formed, if the foreign matter 5 is mixed in the gap between the substrates in the step of bonding the pair of glass substrates 1a and 1b (hereinafter referred to as “substrate bonding step”), the foreign matter 5 The transparent electrodes 2a and 2b may be disconnected due to the pressure applied in the substrate bonding step.

In particular, since the transparent electrodes 2a and 2b are formed of a hard and brittle material such as ITO (Indium Tin Oxide), disconnection easily occurs. In recent years, high definition of liquid crystal panels has been desired, and transparent electrodes 2a,
Although it is necessary to narrow the width of 2b, disconnection was also likely to occur in that case. Further, when colorizing the liquid crystal panel, as shown in FIG. 5, color filters 10R, 10G, 10B are provided between the transparent electrode 2b and the glass substrate 1b.
It is necessary to arrange a resin film such as the above. However, if the above-described foreign matter 5 is mixed in the substrate bonding step, the transparent electrode 2b is pushed by the foreign matter 5 and bent while denting the resin film. As a result, disconnection was likely to occur.

When the transparent electrodes 2a and 2b are disconnected as a result, regardless of any reason, the electrodes 2a and 2b are disconnected.
All the liquid crystals 3 in the portion along 2b are not switched,
There is a problem that line defects occur and image quality deteriorates.

Accordingly, an object of the present invention is to provide a liquid crystal element which suppresses the occurrence of cracks and disconnections in the first electrode and the occurrence of line defects.

Another object of the present invention is to provide a liquid crystal device capable of high definition.

It is a further object of the present invention to provide a liquid crystal device capable of high definition and colorization.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a pair of substrates arranged at a predetermined distance apart from each other and a supporter for at least one of the pair of substrates. A plurality of first electrodes, a plurality of metal second electrodes formed so as to cover a part of the first electrodes, and a liquid crystal disposed in a gap between the pair of substrates. In the device, the width of the first electrode at an arbitrary cross section is T1, and the width of the second electrode at the cross section is T1.
2 and at least in a section where T1 ≦ 50 μm,

[0014]

[Formula 3] T2 ≧ 0.15 · T1 is satisfied.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the present invention will be described.

The liquid crystal device according to the present invention, as shown by reference numeral P ₂ or P ₃ in FIG. 3 and FIG. 5, a pair of substrates 1a arranged in a state in which at a predetermined distance comprises a 1b, these A plurality of first electrodes 2a or 2b are supported on at least one of the pair of substrates 1a or 1b. A plurality of metal second electrodes 4a and 4b are formed so as to cover a part of the first electrodes 2a and 2b.
The liquid crystal 3 is arranged in the gap between a and 1b.

When the width of the first electrode 2a, 2b at an arbitrary cross section is T1, and the width of the second electrode 4a, 4b at the cross section is T2, at least T1
≦ 50 μm,

[0018]

[Formula 4] T2 ≧ 0.15 · T1 is satisfied.

In this case, the above formula may be satisfied in a portion extending over substantially the entire length of the first electrodes 2a and 2b.

The substrates 1a and 1b include transparent substrates such as glass substrates.

Further, the plurality of first electrodes 2a, 2b may be formed in a stripe shape, and the first electrodes 2a, 2b in a stripe shape are formed on each of the pair of substrates 1a, 1b. The first electrodes 2a and 2b in the form of stripes may be arranged orthogonally to form a matrix electrode (see FIGS. 4 and 6). Further, as the first electrodes 2a and 2b, a transparent electrode made of ITO (indium tin oxide) or the like can be used.

The second electrodes 4a and 4b may be made of aluminum or copper.

Further, a resin film may be formed between the first electrode (for example, 2b) and a substrate (for example, 1b) supporting the first electrode (see FIG. 5). As this resin film, color filters 10R, 10G, 10
B, and a protective film 11 formed so as to cover the color filters 10R, 10G, and 10B.

Further, the width of the first electrodes 2a, 2b may be 50 μm or less.

Next, a method of manufacturing the above liquid crystal element will be described.

In manufacturing a liquid crystal element, first, one substrate 1a is formed by sputtering or photolithography.
First, a plurality of first electrodes 2a are formed.

Thereafter, the second electrode 4a is formed so as to cover a part of the first electrode 2a.

Further, the substrate 1a on which the electrodes 2a and 4a are formed and the other substrate 1b are bonded to each other with a predetermined distance therebetween, and the liquid crystal 3 is injected into a gap between the pair of substrates 1a and 1b. I do.

Next, the operation and effect of this embodiment will be described.

According to the present embodiment, the first electrodes 2a, 2
b is at least a narrow portion (that is, T1 ≦ 50
μm, which is inherently susceptible to disconnection), at least 15% of the width of the second electrode 4a,
4b. Therefore, even if a foreign substance indicated by reference numeral 5 in FIG. 1 is mixed in the substrate gap in the substrate bonding step in the stage of manufacturing the liquid crystal element, the first electrodes 2a and 2b are connected to the second electrodes 4a and 4b. 4b, cracks and disconnections caused by the foreign matter 5 are suppressed. As a result, generation of line defects is suppressed, and good image quality can be maintained.

Further, according to the present embodiment, the width of the first electrodes 2a and 2b is not limited in terms of preventing occurrence of line defects, and a high-definition liquid crystal element can be obtained.

Further, when the colorization of the liquid crystal element is performed, it is necessary to arrange resin films such as color filters 10R, 10G and 10B between the first electrode 2b and the substrate 1b as shown in FIG. If the foreign matter 5 is mixed in the substrate bonding step as described above, the first electrode 1b is pushed by the foreign matter 5 and bends while depressing the resin film. Become. But,
When the second electrode 4b is formed so as to cover a part of the first electrode 1b as in the present embodiment, disconnection of the first electrode 1b is suppressed even in a liquid crystal element performing such a color display.

According to the present embodiment, the first electrode 2
Since the second electrodes 4a and 4b are arranged together with the electrodes a and 2b, the wiring resistance can be reduced and the delay of the voltage waveform can be prevented. Accordingly, uniform switching characteristics of the liquid crystal molecules are secured over the entire display area.

[0034]

The present invention will be described below in more detail with reference to examples.

Example 1 In this example, a liquid crystal panel (liquid crystal element) P ₂ shown in FIGS. 3 and 4 was prepared.
The first electrodes 2a and 2b are formed in stripes on the surfaces of the glass substrates 1a and 1b, respectively.
And the first electrode 2b were arranged so as to be orthogonal to each other to form a matrix electrode. In addition, each first electrode 2
The second electrodes 4a and 4b are arranged so as to cover a part of the electrodes a and 2b, and the alignment films 6a and 6b are arranged so as to cover the electrodes 2a, 4a and 2b and 4b. Further, a spacer 7 was disposed in the gap between the substrates to define the gap.

Glass substrates are used for the substrates 1a and 1b, and the transparent electrodes 2a and 2b as the first electrodes are made of ITO.
(Indium tin oxide) and its width T
1 was 39 μm.

The metal electrodes 4a and 4b as the second electrodes
Was made of aluminum having a thickness of about 2000 °, and was formed into a stripe shape having a width T2 of 6 μm.

That is, in this embodiment,

[0039]

[Formula 5] T2 = 6 μm ≧ 0.15 · 39 μm = 0.15 · T1 is satisfied.

The spacer 7 has an average particle diameter of 1.
Silica beads of about 1 μm were used. Further, the alignment film 6
A polyimide film was used for a and 6b, and the thickness was set to about 200 °. As the liquid crystal 3, a ferroelectric liquid crystal exhibiting a chiral smectic phase was used.

Next, a method for manufacturing the liquid crystal panel P _2.

First, an ITO film is formed to a thickness of 700 ° on the surface of the glass substrate 1a by a sputtering method.
This ITO film was patterned by a photolithography method to form a transparent electrode 2a.

Next, an aluminum film was formed by a sputtering method so as to cover the transparent electrode 2a, and the aluminum film was patterned by a photolithographic etching method to form a metal electrode 4a.

Further, a polyimide forming solution is applied to the surfaces of the electrodes 2a and 4a by a spinner.
The alignment film 6a was formed by baking at a temperature of 70 ° C. for 1 hour. Rubbing treatment (uniaxial orientation treatment) was performed on the alignment film 6a by rubbing a rubbing cloth such as nylon in one direction. As a result, a uniaxial orientation axis having an orientation regulating force substantially in the same direction as the rubbing direction was provided.

The surface of the other glass substrate 1b is also
The transparent electrode 2b, the metal electrode 4b, and the alignment film 6b were formed in the same manner as described above.

Next, the pair of glass substrates 1a, 1
The ferroelectric liquid crystal 3 was injected into the gap between the substrates by a vacuum injection method.

Next, the effect of this embodiment will be described.

[0048] was to drive the liquid crystal panel P ₂ created in this embodiment, the line defect was not found at all.

[0049] In Example 2 This example was prepared a liquid crystal panel (liquid crystal device) P ₃ shown in FIGS.

That is, on one glass substrate 1b, three color filters 10R of red, green and blue in the form of dots are provided.
10G and 10B are arranged, and the color filters 10R and 1R are arranged.
The protective film 11 was formed so as to cover 0G and 10B. The transparent electrode 2b as the first electrode is formed on the surface of the protective film 11, and the metal electrode 12b as the second electrode is not in a stripe shape but in the color filters 10R, 10G,
It was formed to have a window-shaped opening corresponding to 10B. The width T1 of the transparent electrode 2b was fixed at 50 μm, and the minimum width T2 of the metal electrode 12b was 8 μm.

On the other glass substrate 1a, a transparent electrode 2a as a first electrode is directly formed on the surface thereof, and a metal electrode 12a as a second electrode is formed in a stripe shape so as to cover a part of the transparent electrode 2a. Formed. The transparent electrode 2a
Has a thickness of 700 ° and a width T1 of 50 μm. The metal electrode 12a has a thickness of 1500 °,
The width T2 was constant at 12 μm.

That is, in the present embodiment, the relationship between the transparent electrode width T1 (= 50 μm) on the side where the color filters 10R, 10G and 10B are formed and the metal electrode width T2 (= 8 μm) is as follows.

[0053]

[Formula 6] T2 = 8 μm ≧ 0.15 · 50 μm = 0.15 · T1. The relationship between the other transparent electrode width T1 (= 50 μm) and the metal electrode width T2 (= 12 μm) is as follows.

[0054]

[Formula 7] T2 = 12 μm ≧ 0.15 · 50 μm = 0.15 · T1 Other configurations are the same as those in the first embodiment.

Next, the effect of this embodiment will be described.

[0056] was allowed to drive the liquid crystal panel P ₃ created in this embodiment, the line defect was not found at all.

[0057] (Comparative Example) This comparative example was prepared a liquid crystal panel P ₄ shown in FIGS.

That is, the upper and lower transparent electrodes 2a and 2b are
In each case, the thickness was 700 ° and the width T1 was constant at 39 μm. Also, metal electrodes 20a and 20b as second electrodes
Has a stripe shape on both the top and bottom, and its thickness is 2300Å.
And the width T2 was 4 μm.

That is, in this comparative example, the relationship between the transparent electrode width T1 and the metal electrode width T2 is:

[0060]

[Formula 8] T2 = 4 μm <0.15 · 39 μm = 0.15 · T1

The other configuration was the same as that of the second embodiment.

[0062] was to drive the liquid crystal panel P ₄ created in this comparative example, the line defect is found numerous.

[0063]

As described above, according to the present invention,
The first electrode has at least a narrow portion (ie, T1
In a portion where ≤50 μm, which is inherently liable to be disconnected, a portion having a width of 15% or more is covered with the second electrode. Therefore, even if foreign matter is mixed in the gap between the substrates in the substrate bonding process at the stage of manufacturing the liquid crystal element, the first electrode is protected by the second electrode, and cracks and disconnections caused by the foreign matter are generated. Is suppressed. As a result, generation of line defects is suppressed, and good image quality can be maintained.

Further, according to the present invention, the width of the first electrode is not limited in terms of preventing occurrence of line defects, and a high-definition liquid crystal element can be obtained.

Further, when colorizing the liquid crystal element, it is necessary to dispose a resin film such as a color filter between the first electrode and the substrate. If mixed, the first electrode may be bent by being pressed by a foreign substance while depressing the resin film, and as a result, the possibility of disconnection may increase. However, when the second electrode is formed so as to cover a part of the first electrode as in the present invention, disconnection of the first electrode is suppressed even in a liquid crystal element performing such a color display.

Further, according to the present invention, since the second electrode is arranged together with the first electrode, the wiring resistance can be reduced and the delay of the voltage waveform can be prevented. Accordingly, uniform switching characteristics of the liquid crystal molecules are secured over the entire display area.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of a conventional liquid crystal panel.

FIG. 2 is a view taken in the direction of the arrow H in FIG. 1;

FIG. 3 is a cross-sectional view illustrating an example of a structure of a liquid crystal panel according to the present invention.

FIG. 4 is a view taken in the direction of the arrow I in FIG. 3;

FIG. 5 is a sectional view showing another example of the structure of the liquid crystal panel according to the present invention.

FIG. 6 is a view taken in the direction of arrow J in FIG. 5;

FIG. 7 is a cross-sectional view illustrating a structure of a liquid crystal panel created as a comparative example.

FIG. 8 is a view as seen from the arrow K in FIG. 7;

[Explanation of symbols]

1a, 1b Glass substrate (substrate) 2a, 2b Transparent electrode (first electrode) 3 Ferroelectric liquid crystal (liquid crystal) 4a, 4b Metal electrode (second electrode) P ₂ liquid crystal panel (liquid crystal element) P ₃ liquid crystal panel (liquid crystal element)

Claims (8)

[Claims] A pair of substrates arranged at a predetermined distance, a plurality of first electrodes supported by at least one of the pair of substrates, and a part of the first electrodes. A liquid crystal device comprising a plurality of second electrodes made of metal formed on a substrate and liquid crystals arranged in a gap between the pair of substrates, wherein a width of an arbitrary cross section of the first electrode is T1, The liquid crystal element according to claim 1, wherein, when the width of the second electrode is T2, at least a cross section satisfying T1 ≦ 50 μm satisfies the following expression: T2 ≧ 0.15 · T1. 2. The liquid crystal device according to claim 1, wherein the following formula is satisfied: T2 ≧ 0.15 · T1 in a portion extending substantially over the entire length of the first electrode. 3. A matrix electrode, wherein the plurality of first electrodes are formed in stripes on each of the pair of substrates, and the first electrodes in stripes formed on the respective substrates are arranged so as to be orthogonal to each other. The liquid crystal device according to claim 1 or 2, wherein: 4. The liquid crystal device according to claim 1, wherein the substrate and the first electrode are transparent. 5. The liquid crystal device according to claim 1, wherein a resin film is formed between the first electrode and a substrate supporting the first electrode. 6. The liquid crystal device according to claim 5, wherein the resin film is a color filter. 7. The liquid crystal device according to claim 5, wherein the resin film is a color filter and a protective film formed to cover the color filter. 8. The liquid crystal device according to claim 1, wherein the width of the first electrode is 50 μm or less.