JPH0581887B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing a full-color liquid crystal display device, and particularly relates to a method for manufacturing a full-color liquid crystal display device, and in particular, a method for manufacturing a full-color liquid crystal display device, in which a transparent substrate is provided with a color filter pattern having poor heat resistance, and a color filter pattern having transparency and conductivity is formed on the color filter pattern of a transparent substrate. The present invention relates to a method of manufacturing a liquid crystal display device that can be driven efficiently and has excellent display quality by applying an electrode plate having a transparent electrode pattern with excellent properties.

(Prior Art) A conventional liquid crystal display device capable of displaying full color is shown in FIG. 3, and is constructed by sealing a liquid crystal 5 between two electrode plates.

The electrode plate on the viewer's side of the display device is also called a color filter, and has striped transparent electrodes 2, red R, green G, Color filter patterns for each color of blue B are provided in this order.
On the electrode plate on the opposite side, transparent electrodes 2 are provided in a stripe shape in a direction perpendicular to the transparent electrodes 2 on the electrode plate on the observer side, and both transparent electrodes 2, 2
By applying a voltage in a time division manner between them, the liquid crystal interposed at the intersection of these transparent electrodes 2, 2 is driven to perform color display.

By the way, in a monochrome liquid crystal display device, there is no color filter pattern for each color of red R, green G, and blue B, and the liquid crystal has a uniform thickness of 8 μm. However, in the above-mentioned full-color liquid crystal display device, the color filter patterns of the above-mentioned red R, green G, and blue B are interposed between the two transparent electrodes 2, 2, which increases the error in the thickness of the liquid crystal 5, and This lowers the voltage applied between both transparent electrodes 2, 2, making it difficult to set the appropriate thickness of the liquid crystal 5.

On the other hand, a full-color liquid crystal display device has also been proposed in which the positions of the color filter pattern and the transparent electrode 2 are exchanged, a color filter pattern is provided on the glass plate 1, and a transparent electrode 2 is provided on the color filter pattern ( (Refer to Japanese Patent Application Laid-Open No. 143725/1983).

(Problems to be Solved by the Invention) However, the transparent electrode 2 is generally composed of an ITO film or a NESA film, which improves conductivity and light transmittance, enables efficient driving, and provides excellent display quality. In order to manufacture the device, heat treatment is performed at 250 to 480 degrees Celsius during or after film formation, whereas the color filter pattern described above is generally constructed by dyeing resin with poor heat resistance, such as gelatin or gris, with dye. However, there was a problem in that both the resin and the dye constituting the color filter pattern were damaged during the heat treatment of the transparent electrode.

In addition, ion plating, sputtering,
A method of forming a transparent electrode at a low temperature without damaging the color filter pattern by a plasma-assisted film forming method such as plasma CVD is also known (see Japanese Patent Publication No. 40450/1983). However, transparent electrodes formed by these methods undergo large changes over time and heat, and lack reliability as transparent electrodes for display devices that are used for long periods of time, so they have not been put to practical use.

Therefore, the present invention forms a transparent electrode with excellent conductivity and transparency on the color filter pattern without damaging the color filter pattern with poor heat resistance, thereby efficiently driving a liquid crystal display device. Therefore, it is an object of the present invention to provide a liquid crystal display device that enables display of excellent quality.

(Means for Solving the Problems) That is, the present invention provides an electrode plate for a liquid crystal display device comprising a transparent substrate provided with a color filter pattern and a transparent electrode provided on the color filter pattern, and a substrate on the opposite side. In the method for manufacturing a liquid crystal display device, the color filter pattern of the transparent substrate is heat-sealed through a sealing material and the liquid crystal is sealed between the electrode plate for the liquid crystal display device and the opposite substrate. On top of the film, an oxygen-deficient thin film of 800 to 3000 angstroms thick, made of indium oxide and tin oxide, and having a transmittance of 83 to 60% for light at a wavelength of 550 nm using air as a reference, is provided at room temperature. An electrode plate is formed by etching a transparent electrode pattern, and then this electrode plate and the opposite substrate are stacked on the periphery with a sealing material interposed between them, and heat-sealed by heating to 180 to 250°C, simultaneously sealing the thin film. Transmittance 90
It is characterized by forming a transparent electrode as ~78%.

(Detailed Description of the Invention) The present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory cross-sectional view of a liquid crystal display device using the electrode plate according to the present invention, and FIG. 2 is an explanatory view showing the planar positional relationship during the manufacturing process of the electrode plate according to the present invention.

As shown in FIG. 1, the electrode plate according to the present invention is used by being placed on the viewer's side of a liquid crystal display device, and includes a transparent substrate 21, color filter patterns R, G, and B, and a transparent electrode 23. is an essential requirement,
Preferably, an alignment film 24 for aligning the liquid crystal is further provided on the transparent electrode 23.

A conventionally known glass substrate can be used as the transparent substrate 21, and a metal pattern may be provided on the glass substrate. This metal pattern can be provided for various purposes. For example, 41, 42, and 43 in FIG. 2 are color filter registers for aligning colors when forming color filter patterns R, G, and B. It is a matching mark.

Also, 44 is a part of this metal pattern,
This is a connector alignment mark for aligning flexible printed circuit connectors and printed circuit boards when connecting them.

Furthermore, 45 is a part of this metal pattern, and is a terminal portion that connects the transparent electrode and the metal pattern in order to apply voltage from the printed circuit connector or printed circuit board to the transparent electrode 23 via this metal pattern. It consists of Since the printed circuit connector and the printed circuit board are connected to the transparent electrode 23 through the metal pattern, it is difficult to solder the transparent electrode 23.
Since the printed circuit connector and the printed circuit board can be soldered to the metal pattern without directly soldering the printed circuit connector and the printed circuit board to the metal pattern, the printed circuit connector and the printed circuit board can be connected reliably and firmly.

In addition, the metal pattern can be used to form a registration mark for printing a seal when sealing a liquid crystal between electrode plates, a mark for aligning both electrode plates, a product identification mark, and the like.

Such a metal pattern can be made of, for example, nickel, chromium, or the like. Further, in order to improve the adhesive strength between the transparent substrate 21 and this metal pattern, an undercoat such as SiO ₂ may be provided between the two.

Further, the color filter patterns R, G, and B according to the present invention color the light beams that pass through each pixel, and can be constructed by a conventionally known dyeing method. In this case, the color filter patterns R, G, and B are formed by dyeing resin such as gelatin or glue with dyes of red R, green G, and blue B, respectively, and as shown in FIG. The glass substrate 21 or the glass substrate 2 according to the pattern
1 on the metal pattern. Alternatively, this color filter pattern 21 may be formed by printing.

Note that the color filter patterns R, G, and B formed by this dyeing method have a thickness of 0.5 to 2 μm,
Color filter patterns R, G, and B formed by printing usually have a maximum thickness of about 5 μm, and the thickness is A corresponding step is created. A transparent electrode 23 is placed on top of this step.
When forming a transparent electrode, it is difficult to accurately control its electrical characteristics, resulting in variations in the resistance value of the transparent electrode 23.In order to prevent this variation and ensure stable driving of the transparent electrode, It is desirable to provide an overcoat layer with a thickness of about 0.2 to 2 .mu.m on the color filter patterns R, G, and B for smoothing. The transparent electrode provided on the surface smoothed by the overcoat layer has a stable resistance value, and therefore the resistance value can be easily controlled, which is advantageous for driving the transparent electrode.

The transparent electrode 23 according to the present invention is formed at a low temperature without damaging the color filter patterns R, G, B while maintaining the characteristics thereof, and has excellent transparency and conductivity. It is something. This transparent electrode is made by first forming a thin film of indium oxide and tin oxide with a thickness of about 800 to 3,000 angstroms in an oxygen-deficient atmosphere. This thin film has a transmittance of 83 to 60% for light with a wavelength of 550 nm using air as a reference, and as shown in the examples described later, a thin film with the desired transmittance can be obtained by appropriately selecting the film forming conditions. can be stably formed into a film.

Next, this thin film was heated to 180 to 250°C without damaging the color filter patterns R, G, and B.
Heat to oxidize. At this time, the film composition changes due to oxidation, and the transmittance increases to 90 to 78%, and the electrical resistivity decreases (the conductivity increases), reducing the burden on the power source for driving the liquid crystal. Note that this heat treatment can be performed at the same time as sealing when assembling the liquid crystal display device.

(Function) As described above, according to the present invention, the color filter pattern is made of indium oxide and tin oxide, and has a thickness of 800 nm to 800 nm, which has a transmittance of 83 to 60% for light at a wavelength of 550 nm using air as a reference. A 3000 angstrom thin film in an oxygen-deficient state was provided at room temperature, and this thin film was etched onto the transparent electrode pattern to form an electrode plate. Next, this electrode plate and the opposite substrate were attached to the periphery via a sealing material. The transmittance of the thin film is increased to 90 at the same time as heat sealing by stacking and heating to 180 to 250℃.
~78% to form a transparent electrode, it can be formed without damaging the color filter pattern while maintaining its characteristics.In addition, it is a transparent electrode with excellent transparency, conductivity, and resistance to aging and heat. Can form electrodes.

Further, according to the embodiment described in claim 2, since the transparent substrate includes an overcoat layer with a smooth surface on the color filter pattern, the resistance value of the transparent electrode is stabilized. Therefore, it is easy to control the resistance value.

(Example) The present invention will be explained below with reference to Examples.

Example 1 A float glass plate with a size of 250 mm x 200 mm and a thickness of 1.1 mm was used as a transparent substrate.
A chromium film with a thickness of 500 angstroms and a nickel film with a thickness of 4000 angstroms were deposited. Next, the chromium film and nickel film were etched using the well-known photolithography method to form a metal pattern.

Next, on this metal pattern, a three-color filter pattern of red, green, and blue was formed in the form of a stripe pattern with a pitch of 300 μm. A well-known dyeing method was used for the color filter pattern, and Griyu was used as the resin.

Then, add 2 on this color filter pattern.
A thin film with a thickness of about 1100 angstroms was formed according to the original evaporation method. 99.99% purity as a vapor deposition source
using indium oxide and tin oxide, and the film forming conditions were as follows:
Substrate temperature: room temperature, oxygen partial pressure: 4×10 ⁻⁴ torr., high frequency voltage: 3 kV. The thin film thus formed contained 10 mol % of tin oxide, had a transmittance of 81% for light (wavelength 550 nm) using air as a reference, and a sheet resistivity of 65 Ω/□.

Next, this thin film was processed into a predetermined shape. The well-known photolithography method was used as a processing method, and etching was carried out by immersion in a 5% aqueous hydrochloric acid solution for 3 minutes. Its shape has a stripe shape with a pitch of 300 μm in the center so that the thin film is located on the color filter pattern, and the nickel film and the thin film overlap for a length of 5 mm at the terminal part, and the two contact each other. It has a conductive shape.

After drying the obtained substrate, it was manufactured by Hitachi Chemical Co., Ltd.
HL-1100 (polyimide material for alignment film) was applied except for the terminal portions and seal portions, and dried at 1500° C. for 1 hour to form an alignment film with a thickness of 600 angstroms.

Next, assuming the sealing of the liquid crystal display device with epoxy resin, we set the temperature to 180℃, which is the same as the temperature at the time of sealing.
C. for 1 hour to oxidize the thin film. When the above-mentioned light transmittance and sheet resistivity of the transparent electrode obtained by heat-treating the thin film were measured in the area where the alignment film was not formed, the light transmittance was 86% and the sheet resistivity was 32%.
Ω/□, and it was confirmed that both transparency and conductivity were improved by heat treatment.

Finally, a flexible printed circuit connector was connected to the terminal of the nickel film.
This flexible printed circuit connector uses a polyimide film as a base material, and a 25 μm thick copper foil circuit is formed on this base material at the same pitch as the nickel film terminals. For connection, 5μm thick copper foil circuit
solder is attached. The two were connected by applying pressure for 10 seconds using a hot press with a tip temperature of 220°C.

Example 2 A float glass plate with a size of 5 inches square and a thickness of 1.1 mm was used as a transparent substrate, and SiO ₂ with a thickness of 500 angstroms was sequentially deposited on this by sputtering method.
(silicon oxide) and a nickel film having a thickness of 3000 angstroms were formed, and a metal pattern of the nickel film was formed in the same manner as in Example 1.

Next, using the same material as in Example 1, a color filter pattern was formed on this metal pattern. However, the color filter pattern has a shape in which each color constitutes a dot of 190 μm vertically and 590 μm horizontally, and these dots are arranged at a pitch of 200 μm vertically, 480 dots horizontally.
The shape was such that 128 pieces were lined up at a pitch of 600 μm.

Next, on this color filter pattern, the same resin used for this color filter pattern is applied to a thickness of 0.5 μm, exposed and developed to expose the above-mentioned nickel film on the terminal part and seal part. The entire color filter pattern was coated to smooth the surface.

Next, a thin film with a thickness of about 1200 angstroms was formed on this smoothing layer by sputtering. Indium oxide and tin containing 5% by weight of tin oxide were used as targets, and the film formation conditions were as follows.
Substrate temperature: room temperature, argon flow rate: 80 SCCM, high frequency effective power: 300 W, oxygen partial pressure: 1 × 10 ^-5 torr. The resulting thin film had a transmittance of 83% for light (wavelength: 550 nm) using air as a reference, and a sheet resistivity of 42 Ω/□.

Next, using the photolithography method as in Example 1, it was processed into stripes with a line width of 170 μm and a pitch of 200 μm. However, this stripe shape is a pattern divided into upper and lower parts at the center.

Subsequently, in the same manner as in Example 1, an alignment film was formed and the thin film was oxidized by heat treatment. When the above-mentioned light transmittance and sheet resistivity of the thus obtained transparent electrode were measured at a portion where no alignment film was formed, the light transmittance was 88% and the sheet resistance was 27Ω/□. It was confirmed that both characteristics were improved.

(Effects of the Invention) According to the present invention, it is possible to form a transparent electrode that maintains the characteristics of the color filter pattern without damaging it, and has excellent transparency, conductivity, and resistance to aging and heat. As a result, the liquid crystal can be driven directly and stably without using a color filter pattern, and it can be driven efficiently with low resistance for a long period of time, making it possible to display full color with high brightness and excellent quality.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional explanatory diagram of a liquid crystal display device using an electrode plate according to the present invention, Fig. 2 is an explanatory diagram showing the planar positional relationship during the manufacturing process of the electrode plate according to the present invention, and Fig. 3 is an explanatory diagram of a conventional liquid crystal display device. FIG. 2 is a cross-sectional explanatory diagram of a liquid crystal display device using the electrode plate of FIG. 1, 21, 46... Transparent substrate, 3, 23... Transparent electrode, 24... Alignment film, 45... Metal pattern, 5, 25... Liquid crystal, R, G, B... Color filter pattern.

Claims (1)

[Scope of Claims] 1. An electrode plate for a liquid crystal display device comprising a transparent substrate provided with a color filter pattern and a transparent electrode provided on the color filter pattern and the opposite substrate are heated through a sealing material in the periphery. In a method for manufacturing a liquid crystal display device in which liquid crystal is sealed between the electrode plate for the liquid crystal display device and the opposite substrate, indium oxide and tin oxide are added on the color filter pattern of the transparent substrate. An oxygen-deficient thin film with a thickness of 800 to 3000 angstroms with a transmittance of 83 to 60% for light at a wavelength of 550 nm using air as a reference is provided at room temperature, and this thin film is etched onto the transparent electrode pattern to form the electrode. A plate is formed, and then this electrode plate and the opposite substrate are stacked on the periphery with a sealing material interposed between them, and the transmittance of the thin film is increased to 90% while heat-sealing by heating to 180 to 250°C.
A method for manufacturing a liquid crystal display device, characterized in that a transparent electrode is formed with a content of ~78%. 2. The method of manufacturing a liquid crystal display device according to claim 1, wherein the transparent substrate includes an overcoat layer having a smooth surface on the color filter pattern.