JPH07120771A - Liquid crystal display device with low-resistance electrode and preparation thereof - Google Patents

Abstract

PURPOSE: To produce a liq. crystal display device with low resistance electrodes reducing line resistance, suppressing line voltage drop between both sides and ensuring uniform display quality. CONSTITUTION: The entire surface of a glass substrate S with a formed ITO film 10 is coated with a photoresist, this photoresist is patterned by exposure through a Cr mask and development so that it is parted at prescribed intervals and the ITO film 10 is etched with an ITO etching soln. so as to form the same pattern as the pattern of the photoresist. The substrate S with transparent ITO electrodes 10 formed at prescribed intervals is subjected to prim. electroless plating and sec. electroless plating to form 1st and 2nd metallic films 12, 14 on both sides of each of the electrodes 10 and then the photoresist is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to Super Twisted Nematic.
c; referred to as "STN") liquid crystal display (LCD), and more specifically, Ni, Ni + Al, or Ni, Ni using electroless plating on both sides of the ITO electrode.
The present invention relates to a liquid crystal display element in which a plating film made of + Au is formed to improve display characteristic defects due to a potential difference between the drive IC side and the opposite side when a voltage is applied.

[0002]

2. Description of the Related Art With the recent spread of OA equipment and small portable TVs, liquid crystal displays (LCD), sensor elements, plasma display panels (PDP), in place of cathode ray tubes (CRTs) in conventional display devices,
Research on fluorescent display panels (VFD) and the like has been actively conducted, and some of them have been put to practical use.

Among them, the liquid crystal display is particularly lightweight, thin, low-value and low-power-consumption, and has good compatibility with an integrated circuit. Therefore, it is suitable for a laptop computer or a portable computer. In addition to the display on a pocket computer, it is expanding its use as a vehicle-mounted device and a color TV image.

In such a liquid crystal display element, two conductive plate materials are arranged in parallel, and liquid crystal is injected between them to display characters, numbers and other arbitrary patterns by an electro-optical effect. .

The liquid crystal display device manufactured in the above process is designed to display an image by utilizing the property of being oriented when a substance having galvanic anisotropy is placed in an electric field.
It has a structure in which a cholesteric or nematic liquid crystal is injected into a liquid crystal cell which is provided by surrounding the upper and lower glass substrates on which a transparent electrode and an alignment film are laminated with a sealing material.

When a voltage is applied to the transparent electrodes formed on the upper and lower glass substrates and an electric field is formed therebetween, the liquid crystal contained in the liquid crystal is oriented in a direction selected by the alignment film due to galvanic anisotropy. When it is twisted, the light incident from the outside is refracted in the molecule side direction. As a result, the portion where the twisted liquid crystal is present in the display area of the liquid crystal shows a difference in light transmittance from the portion where the twisted liquid crystal is not present, thereby enabling image display.

[0007]

Based on the above-mentioned matters, ITO (indium-tin-oxide) of a conventional liquid crystal display device is used.
The pattern structure will be described below with reference to FIGS. 1 (A) and 1 (B). Here, FIG. 1 (A)
Shows a plan view, and FIG. 1B shows a cross-sectional view.

As can be seen from FIG. 1, the conventional liquid crystal display element uses ITO as a transparent electrode on a glass substrate, and thus has a relatively large line resistance. That is, when a voltage is applied in the external module, a voltage is applied to the ITO pattern and the liquid crystal is twisted.
When the pattern length is 640 × 480 dots, the thickness is 0.2 μm and the width is 270 μm, so the length is 18 c.
It is about m.

As a result, a voltage difference is generated between the first stage portion and the last portion to which a voltage is applied, which causes a problem that good display characteristics cannot be obtained.

Further, when the driving IC is mounted only on one side as the LCD becomes larger, the ITO transparent electrode becomes thin and long, and at the time of voltage application, the voltage application side end (IC drive side) and the opposite side. There will be a potential difference between the ends.

The above-mentioned potential difference has a minimum line resistance of ITO of 10 to 30 Ω / c when only transparent electrodes are used.
m, the line voltage drop (Line Volt
There is a problem that the image drop occurs on both sides of the display screen, resulting in a defective image quality.

Therefore, the present invention has been made in consideration of the above points, solves the above problems, reduces the line resistance due to the line voltage drop between both sides of the transparent electrode, and obtains a uniform display quality. An object of the present invention is to provide a liquid crystal display device having a low resistance electrode and a method for manufacturing the same.

[0013]

In order to achieve the above-mentioned object, a liquid crystal display device of the present invention comprises an ITO transparent electrode formed on a glass substrate at a predetermined interval and both sides of the ITO transparent electrode. It has a low resistance electrode having a structure composed of the formed first and second metal films.

On the other hand, in the method for manufacturing a liquid crystal display device according to the present invention, a photoresist coating is applied to the entire surface of the disk-shaped glass on which the ITO film is formed, and then the photoresist is exposed and developed using a chrome mask, and the photoresist is provided at predetermined intervals. And patterning so as to be separated from each other, etching the ITO film using an ITO etching solution so as to have the same pattern as the photoresist, and forming a first layer on the substrate on which the pattern is formed. And second electroless plating to form the first and second metal films on both sides of the ITO film, and after the process, etching the photoresist.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

2 (A) to 2 (C) are a plan view and a sectional view showing an ITO pattern structure of a liquid crystal display device according to an embodiment of the present invention.

As can be seen from FIG. 2, the liquid crystal display device according to the present embodiment has ITO transparent electrodes (10) formed on a glass substrate S at a predetermined interval, and formed on both sides of the ITO electrodes. The first and second metal films (12, 1)
4) has a structure consisting of

This structure is formed by STN using electroless plating.
It lowers the line resistance, which is closely related to LCD.
In the manufacturing method, first, a photoresist is coated on the entire surface of the disk glass S on which the ITO film is formed, and then exposed and developed using a chrome mask so that the photoresists are separated from each other at a predetermined interval. Pattern.

Then, an ITO etching solution is used to form an ITO film having the same pattern as the photoresist.
The film (10) is etched, but at this time, since the ITO etching solution does not etch the photoresist,
The ITO film under the photoresist remains as it is, and only the other part is etched, and the glass of the etched part appears on the surface.

Subsequently, the pattern is plated by an electroless Ni plating method. Here, since the Ni plating does not form a plating on the glass and on the photoresist component, the plating is formed only on the ITO portion.

At present, the metal used in the electroless plating is Ni seed or Au, and in this embodiment, since the Au electroless plating is performed again on the Ni-plated pattern, the ITO film is formed. Ni (12) and Au (14) are formed on both sides of (10).

At this time, the Ni and Au metal films formed on both sides of the ITO film (10) have the same thickness as the ITO film, or are formed so that the corners on both sides are partially covered. It will consist of one of the selected ones.

On the other hand, the Ni and Al plating film can be formed as Ni and Ni and Al (Ni + Al) or Ni and Ni and Au (Ni + Au) other than this.

After the above steps, the photoresist formed on the ITO film (10) is removed to complete the liquid crystal display device according to the present invention. here,
The plating amount of Ni becomes proportional to the time (the time of putting in the electroless plating solution).

In the case of B / W (Black and White) STN, the width of the ITO film (10) is 270.
The distance between the ITO films (10) is 30 μm.
m, the thickness is about 2000 ⌒ when the line resistance is 15Ω.

On the other hand, the film thicknesses of Ni and Au plating are each 0.05 to 3 μm.

As a result, in the class higher than the B / W STN LCD, a normal twisted nematic (TN) is used.
In case of STN, 300Ω, in case of STN 10-15Ω /
The resistance value (sheet resistance) that was □ will be reduced.

[0028]

As described above, according to the present invention,
By forming the Ni and Au plating films on both sides of the ITO transparent electrode, the line resistance can be reduced and the line voltage drop between both sides of the transparent electrode can be significantly reduced, and uniform and good display quality can be obtained.

Further, according to the method of manufacturing a liquid crystal display element of the present invention, the step of forming the first and second metal films on both sides of the ITO transparent electrode by electroless Ni plating or the like is included, and the line resistance is reduced. Therefore, it is possible to suppress an increase in the cost of the manufacturing process, significantly reduce the line voltage drop between both sides of the transparent electrode, and obtain uniform and good display quality. Further, according to the present invention, the primary and secondary electroless platings preferably contribute to the reduction of the line resistance when Ni or Au metal is used. The effects of the present invention can be similarly achieved by the manufacturing methods according to claims 4 to 6.

[Brief description of drawings]

1A and 1B are ITO of a conventional liquid crystal display device.
It is the top view and sectional drawing which showed the pattern structure.

2A to 2C are a plan view and a cross-sectional view showing an ITO pattern structure of a liquid crystal display device according to an embodiment of the present invention.

[Explanation of symbols]

 S glass substrate 10 ITO film 12 Ni 14 Au

Claims (6)

[Claims] 1. A low resistance electrode comprising an ITO transparent electrode formed on a glass substrate at a predetermined interval, and first and second metal films formed on both sides of the ITO transparent electrode. Liquid crystal display device. 2. A photoresist is coated on the entire surface of the disk-shaped glass on which the ITO film is formed, and then exposed and developed using a chrome mask so that the photoresists are separated from each other at a predetermined interval. Patterning, etching the ITO film using an ITO etching solution to have the same pattern as the photoresist, and forming a primary and secondary electroless plating layer on the patterned substrate. A liquid crystal display device having a low resistance electrode, comprising: a step of forming first and second metal films on both sides of the ITO film; and a step of removing the photoresist after the step. Production method. 3. The primary and secondary electroless plating is N
The method for manufacturing a liquid crystal display device having a low resistance electrode according to claim 2, wherein the liquid crystal display device is made of i or Au metal. 4. The first metal film and the second metal film are formed of any one selected from Al and Ni, Ni and Al and Ni, Ni and Ni and Au. A method of manufacturing a liquid crystal display device having a low resistance electrode according to claim 2. 5. The method according to claim 2, wherein the first metal film Ni and the second metal film Al are each formed to a thickness of 0.05 to 3 μm. A method for manufacturing a liquid crystal display device having a low resistance electrode. 6. The first and second metal films formed on both sides of the ITO film are formed to have the same thickness as the ITO film, or the corners on both sides are partially covered. The method for manufacturing a liquid crystal display device having a low resistance electrode according to claim 2, wherein the method comprises forming one of the selected ones.