JP2594955B2 - Liquid crystal display - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology effective when applied to a liquid crystal display device, in particular, a multi-gap type color liquid crystal display device.

[Conventional technology]

The display of each pixel in the liquid crystal display section is represented by a thin film transistor (TF
A multi-gap type color liquid crystal display device controlled by T) is known. This liquid crystal display device is configured such that liquid crystal is sealed in a space between a lower transparent glass substrate and an upper transparent glass substrate. On the inner surface (liquid crystal side) of the lower transparent glass substrate, a transparent pixel electrode provided for each pixel and a thin film transistor provided for each pixel for controlling a voltage applied thereto are provided. A color filter and a common transparent pixel electrode facing the transparent pixel electrode are provided on the inner surface (liquid crystal side) of the upper transparent glass substrate.

A spacer member is provided in a space between the lower transparent glass substrate and the upper transparent glass substrate and in a region where liquid crystal is sealed. The spacer member is configured to define the gap of the space, that is, the thickness of the liquid crystal. The spacer member is provided for appropriately controlling the shutter and the contrast of the liquid crystal display unit. The spacer member is formed of glass fiber, alumina particles, plastic, beads, or the like having a uniform size, and is dispersed in the liquid crystal.

In this type of multi-gap type color liquid crystal display device, the filter thickness is changed for each of the red, green, and blue color filters to change the gap of the liquid crystal. The control of the gap of the liquid crystal is performed to control the transmittance of the liquid crystal for each color. Usually, in the color filter, the blue filter is formed with the largest thickness, and the red filter is formed with the smallest thickness. Therefore, the gap in the liquid crystal is substantially defined by the thickness of the blue filter and the size of the space member formed in the region.

To seal the liquid crystal, a large-sized sealing spacer member obtained by adding the size of the spacer member to the film thickness of the blue filter is used. This sealing spacer member is disposed at a peripheral portion between the lower transparent glass substrate and the upper transparent glass substrate so as to remove the liquid crystal sealing opening. The sealing spacer member is covered with an epoxy resin material.

The liquid crystal display device is described in, for example, Nikkei Microdevice, November 1986, pp. 51-53.

[Problems to be solved by the invention]

In the above-described multi-gap type color liquid crystal display device, two types of spacer members, a spacer member in the liquid crystal and a sealing spacer member for sealing the liquid crystal, are used. For this reason, the present inventor has found a problem that it is extremely difficult to control the gap of the liquid crystal due to the processing accuracy of each spacer member of the liquid crystal display device.

An object of the present invention is to provide a technique capable of easily controlling a gap of a liquid crystal in a multi-gap type color liquid crystal display device.

Another object of the present invention is to provide a technique capable of achieving the above object and reducing the number of manufacturing steps.

The above and other objects and novel features of the present invention are as follows.
It will become apparent from the description of the present specification and the accompanying drawings.

[Means for solving the problem]

The outline of a typical invention disclosed in the present application is briefly described as follows.

In a multi-gap type color liquid crystal display device,
Among the color filters of the color filters, the color filter having the largest thickness is provided in the seal region, and the spacers of substantially the same size are provided in the regions corresponding to the color filters in the liquid crystal and the color filters in the seal region. A member is provided.

(Operation)

According to the above-described means, since the gap of the liquid crystal can be defined by the spacer members having substantially the same size, the gap of the liquid crystal can be easily controlled.

Hereinafter, the configuration of the present invention will be described together with an embodiment in which the present invention is applied to a multi-gap type color liquid crystal display device employing an active matrix system.

In all the drawings for describing the embodiments, components having the same function are denoted by the same reference numerals, and their repeated description will be omitted.

〔Example〕

FIG. 2 (a cross-sectional view of a main portion) shows a main portion of a liquid crystal display portion of a multi-gap type color liquid crystal display device according to an embodiment of the present invention.

As shown in FIG. 2, the liquid crystal display device has a thin film transistor TFT and a transparent pixel electrode ITO (indium oxide, indium oxide) on a surface inside (liquid crystal side) of a lower transparent glass substrate SUB1 having a thickness of about 1.1 [mm]. It has a pixel made of tin oxide (1).

The thin film transistor TFT mainly includes a gate electrode GT, an insulating film GI used as a gate insulating film, an i-type semiconductor layer AS used as a channel formation region, a source electrode SD1, and a drain electrode SD2.

The gate electrode GT is formed of, for example, a composite film in which a Mo layer is laminated on a Cr layer in order to prevent disconnection. The gate electrode GT is formed integrally with and connected to a scanning signal line (horizontal signal line).

The i-type semiconductor layer AS is used as a channel forming region of the thin film transistor TFT. The i-type semiconductor layer AS is formed of an amorphous silicon film or a polycrystalline silicon film.

The source electrode SD1 and the drain electrode SD2 are separately provided on the i-type semiconductor layer AS. Source electrode SD
1. Each of the drain electrodes SD2 is configured such that when the bias polarity of the circuit changes, the source and the drain are switched in operation. That is, the thin film transistor TFT is bidirectional, like the FET.

Each of the source electrode SD1 and the drain electrode SD2 is, for example,
From the lower side in contact with the i-type semiconductor layer AS, a high impurity concentration
It is formed by sequentially laminating an n ⁺ type semiconductor layer, a Cr layer, and an Al layer. The n ⁺ -type semiconductor layer is formed of an amorphous silicon film or a polycrystalline silicon film, and is configured to reduce a contact resistance value with the i-type semiconductor layer AS. Cr layer is Al
It is formed as a barrier layer that prevents reaction with the layer. The Al layer has a low resistance value to increase the signal transmission speed, and is used as a main wiring material.

A transparent pixel electrode ITO1 provided for each pixel is connected to one source electrode SD1 of the thin film transistor TFT.
The transparent pixel electrode ITO1 constitutes one of the pixel electrodes of the liquid crystal display. The other drain electrode SD2 is formed integrally with and connected to a video signal line (vertical signal line).

On the thin film transistor TFT and the transparent pixel electrode ITO1,
A protective film PSV1 is provided. The protective film PSV1 is mainly formed to protect the thin film transistor TFT from moisture and the like, and is formed of a silicon oxide film or a silicon nitride film having high transparency and excellent moisture resistance.

On top of the protective film PSV1 on the thin film transistor TFT, an i-type semiconductor layer where external light is used as a channel formation region
A shielding film LS is provided so as not to be incident on the AS.
The shielding film LS is formed of, for example, an Al layer or a Cr layer.

The thin film transistor TFT is configured such that when a positive bias is applied to the gate electrode GT, the channel resistance between the source and the drain decreases, and when the bias is set to zero, the channel resistance increases. That is, the thin film transistor TFT is configured to control the voltage applied to the transparent pixel electrode ITO1.

The liquid crystal LC includes a lower alignment film ORI1, an upper alignment film ORI2 for setting the orientation of liquid crystal molecules, a spacer member SP1, and a sealing spacer in a space formed between the lower transparent glass substrate SUB1 and the upper transparent glass substrate SUB2. Defined and enclosed in member SP2.

The lower alignment film ORI1 is a protective film on the lower transparent glass substrate 1 side.
Formed on top of PSV1. The lower alignment film ORI1 is, for example,
It is formed of a photosensitive polyimide resin material.

On the inner (liquid crystal side) surface of the upper transparent glass substrate SUB2, a color filter FIL, a protective film PSV2, a common transparent pixel electrode ITO2, and the upper alignment film ORI2 are sequentially laminated.

The common transparent pixel electrode ITO2 has a lower transparent glass substrate SU
Facing the transparent pixel electrode ITO1 provided for each pixel on the B1 side,
It is configured integrally with another adjacent common transparent pixel electrode ITO2.

The color filter FIL is configured by dyeing a dyeing base material formed of a resin material such as an acrylic resin with a dye for each pixel. That is, the color filter FIL
Are red filter R, green filter G, blue filter B
Are arranged to face each other for each pixel. FIG. 2 shows only the blue filter B portion of the color filter FIL, but FIG. 1 (schematic sectional view) shows the arrangement of each color filter R, G, B.

The thickness of each color filter of the same color is substantially uniform. That is, the gap of the liquid crystal LC of the pixel displaying the same color is configured to be uniform, and the control of the shutter and the control of the contrast of the liquid crystal display unit can be appropriately performed. The color filter FIL changes the thickness of the color filter for each color, that is, for each of the red filter R, the green filter G, and the blue filter B.
Is changing the gap. That is, this liquid crystal display device employs a multi-gap method. The control of the gap of the liquid crystal LC for each color filter is performed to control the transmittance of the liquid crystal LC for each color. Normally, the red filter R has the smallest film thickness (for example, 10,000 to 15000 [Å]), and the green filter G has an intermediate film thickness (for example, 15,000 to 20,000).
[Å]), the blue filter B is formed with the thickest film thickness (for example, 20,000 to 25000 [Å]).

The color filter FIL is provided not only in the area where the liquid crystal LC is sealed (in the liquid crystal display unit) but also as shown in FIGS. 1 and 2 at the peripheral edges of the lower transparent glass substrate SUB1 and the upper transparent glass substrate 2, respectively. It is also configured in a sealing area for sealing the liquid crystal LC. The color filter FIL formed in the seal area is provided with a blue filter B having the largest film thickness among the color filters.

The method of manufacturing the color filter FIL will be briefly described with reference to FIGS. 3 to 5 (simulated partial cross-sectional views showing respective manufacturing steps).

First, a dyed base material is formed on the entire surface of the upper transparent glass substrate SUB2, and only the dyed base material in the red filter forming region is left by photolithography. Thereafter, the dyed base material is dyed with a red dye and fixed with an aqueous tannic acid solution or the like to form a red filter R as shown in FIG.

Next, the dyed base material is formed again on the entire surface of the upper transparent glass substrate SUB2 covering the red filter R, and only the dyed base material in the green filter formation region is left by photolithography. Then, like the red filter R,
The remaining dyed base material is dyed with a green dye and subjected to a fixing treatment to form a green filter G as shown in FIG.

Next, on the entire surface of the upper transparent glass substrate SUB2, which covers the red filter R and the green filter G, a dyeing base is formed again, and only the dyeing base in the blue filter forming region is left by photolithography. . At this time, the dyed base material is formed on the surface of the upper transparent glass substrate SUB2 in the region where the liquid crystal LC is sealed and in the sealing region. Thereafter, the remaining dyed base material is dyed with a blue dye and subjected to a fixing treatment in the same manner as described above to form a blue filter B as shown in FIG.

The protective film PSV2 is provided in order to prevent the dye obtained by dyeing the color filter FIL into different colors from leaking into the liquid crystal LC. The protective film PSV2 is formed of, for example, a transparent resin material such as an acrylic resin or an epoxy resin.

The space member SP1 is provided in a region where the liquid crystal LC is sealed, and is substantially uniformly dispersed. As shown in FIGS. 1 and 2, a space member SP1 formed in a region corresponding to the blue filter B defines a substantial gap of the liquid crystal LC.

The sealing space member SP2 is provided in a region where the thickest blue filter B is formed in the sealing region. The sealing space member SP2 is formed in substantially the same size as the sealing member SP1.
This sealing space member SP2 is the same as the space member SP1.
In the same manner as described above, a substantial gap of the liquid crystal LC is defined. This sealing spacer member SP2 is made of a sealing material S
Protective film PSV of lower transparent glass substrate SUB1 covered by L
1. The protective film PSV2 of the upper transparent glass substrate SUB2 is bonded to each. Space member SP1, Seal space member SP
2 is made of glass fiber, alumina particles, beads, etc., and has a size (diameter) of, for example, about 70,000 [0000]. The sealing material SL is formed of, for example, an epoxy resin material. Since the epoxy resin material has poor adhesion to the polyimide resin material, the upper alignment film ORI1 and the lower alignment film ORI2 are not formed in the sealing material SL formation region. Further, the gap in the region where the blue filter B is formed in the liquid crystal LC and the gap in the region where the blue filter B is formed in the sealing region are slightly different from each other by an amount corresponding to the alignment films ORI1 and ORI2. Since the film thickness of ORI1 and ORI2 is formed as thin as 500 to 700 [Å], for example,
It does not affect the control of the gap of the liquid crystal LC.

As described above, in the multi-gap type color liquid crystal display device, among the color filters of the color filter FIL,
A blue filter B having the thickest film thickness is provided in the seal region, and a spacer member SP1 is provided in a region corresponding to each color filter R, G, B in the liquid crystal LC, and in a region corresponding to the blue filter B in the seal region. By providing the sealing space member SP2 of substantially the same size as the space member SP1, the gap of the liquid crystal LC can be defined by each of the spacer member SP1 and the sealing space member SP2 of the same size. In addition, the gap of the liquid crystal LC can be easily controlled.

Further, as shown in FIG. 5, the blue filter B provided in the seal region can be formed in the same manufacturing process as the blue filter B in the region where the liquid crystal LC is sealed (in the liquid crystal display unit). , The step of forming the blue filter B provided in the first embodiment can be eliminated, and the number of manufacturing steps can be reduced.

In the liquid crystal display device, the respective layers on the lower transparent glass substrate SUB1 side and the upper transparent glass substrate SUB2 side are separately formed, and then the upper and lower transparent glass substrates SUB1 and SUB2 are overlapped, and the liquid crystal 11 is sealed therebetween. Assembled by.

The central part of FIG. 2 shows a cross section of one pixel portion. The left side shows a cross section of a portion where the lead wiring exists at the left peripheral portion of the transparent glass substrates SUB1 and SUB2. The right side shows a cross section of a portion on the right peripheral portion of the transparent glass substrates SUB1 and SUB2 where no lead wiring exists. The lead wires are the gate electrode GT and the source electrode S of the thin film transistor TFT.
It is formed in the same manufacturing process as D1 and the drain electrode SD2.

The common transparent pixel electrode IT on the upper transparent glass substrate SUB2 side
O2 is connected to a lead wiring layer formed on the lower transparent glass substrate SUB1 side by a silver paste material SIL at at least one position.

Polarizing plates POL are formed on the outer surfaces of the lower transparent glass substrate 1 and the upper transparent glass substrate 12, respectively.

As described above, the invention made by the inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and can be variously modified without departing from the gist thereof. Of course.

For example, the present invention can be applied to a multi-gap type color liquid crystal display device employing a time division driving method.

〔The invention's effect〕

The effects obtained by the representative inventions among the inventions disclosed in the present application will be briefly described as follows.

In a multi-gap type color liquid crystal display device,
It is possible to easily control the gap of the liquid crystal.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a multi-gap type color liquid crystal display device according to one embodiment of the present invention, FIG. 2 is a main part cross-sectional view showing a specific configuration of the color liquid crystal display device, FIG. 5 to FIG. 5 are schematic cross-sectional views of the color liquid crystal display device for each manufacturing process of the color filter. In the figure, SUB1 ... upper transparent glass substrate, SUB2 ... lower transparent glass substrate, FIL ... color filter, R, G, B ... color filter, SP1 ... space member, SP2 ... ... seal space member, SL ... seal material, LC ... liquid crystal, TFT ... thin film transistor.

Claims (4)

(57) [Claims] 1. A liquid crystal display device in which a gap between spaces is controlled by interposing a spacer member between a lower substrate and an upper substrate on which a color filter is formed, and a liquid crystal is sealed in the space. One is transparent, and among the color filters of the color filter, a color filter having the largest film thickness is provided on the surface of the upper substrate in the seal region for sealing the liquid crystal, and further covers the thin film transistor, and the lower substrate The protective film on the side and the color filter are covered, and a protective film on the upper substrate side is provided in the seal region for sealing the liquid crystal, while the alignment films on the upper and lower substrate sides are in the seal region. A thin film, wherein a spacer member of substantially the same size is provided in a region corresponding to each color filter in the liquid crystal and the color filter in the seal region without being formed. The liquid crystal display device of the transistor system. 2. A color filter comprising a red filter, a green filter and a blue filter, wherein a blue filter having the largest film thickness is provided in the sealing region. A thin film transistor type liquid crystal display device according to claim 1. 3. A spacer member provided in the seal region is covered with a seal material made of an epoxy resin material, a protective film on a lower substrate side is made of a silicon oxide film or a silicon nitride film, 3. The protective film according to claim 1, wherein the protective film is made of an acrylic resin material or an epoxy resin material, and the upper and lower substrate side alignment films are made of a polyimide resin. The liquid crystal display device of a thin film transistor system according to the above. 4. The thin film transistor according to claim 1, wherein the color filters in the sealing region are formed in the same manufacturing process as the color filters in the liquid crystal. Liquid crystal display device.