JPH03184078A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To make a large-capacity display of high display quality by arraying striped electrodes on the mutually opposite surfaces of insulating substrates at right angles to each other and covering them with oriented films, and injecting specific ions into the oriented films above the transparent electrodes. CONSTITUTION:The transparent electrodes 3 are formed in stripes of transparent conductive films of ITO, etc., on the surfaces of the insulating substrates 1 and 2 and polyacetylene is used as an orienting agent and applied, and then baked to form the oriented films 4. Then Na<+> ions are injected selectively into the oriented films 4. The ions are injected only right above the striped transparent electrodes 3. Thus, the specific ions are injected into the orienting films 4 to decrease the resistance values of the oriented films 4 and then the voltage drops of the oriented films in the ON state become small, so a voltage applied to liquid crystal rises. Consequently, crosstalk and contrast are small and the large-capacity display of high display quality is made.

Description

[Detailed description of the invention]

[Summary] Regarding a method of manufacturing a liquid crystal display device to improve crosstalk and contrast in the liquid crystal display device and improve display quality, this method eliminates structural fluctuation factors of the liquid crystal display device with respect to applied voltage vs. brightness characteristics. For the purpose of The alignment film has a structure in which predetermined ions are implanted into the upper part of the transparent electrode. [Industrial Application Field] The present invention relates to a method of manufacturing a liquid crystal display device for improving crosstalk and contrast in the liquid crystal display device and improving display quality. [Prior Art] In a liquid crystal display device, various electrodes are formed on the surfaces of a pair of insulating substrates, an alignment film is formed thereon, the alignment film is subjected to a rubbing process, and then a liquid crystal is placed between the two substrates. Enclose. In the conventional liquid crystal display device described above, the brightness characteristics with respect to the voltage applied to the liquid crystal cell vary due to the data pattern and the rounding of the voltage waveform. When an off-voltage is applied, the characteristic of curve A in FIG. 2 is shown, and when the on-voltage is applied when the entire screen is displayed in white, the characteristic of curve B is shown. However, when white and black are mixed, the on-characteristic shifts between A and B. The line labeled C in the figure is an example. Furthermore, this shift amount is also affected by the rounding of the voltage waveform, and if the rounding is large, the effective value will decrease, resulting in a large shift. Therefore, as a result of various studies on this variation, the inventors of the present application found that when adjacent pixels alternately change to white and black, even if the waveform is almost completely unrounded, a shift of about 0.5V is still observed. However, if the alignment film is removed and the transparent conductive film is rubbed directly, if the waveform is not rounded,
It was found that the above fluctuation did not occur at all. [Problem to be solved by the invention] This mechanism is not necessarily clear, but when a voltage is applied, a displacement current flows through the liquid crystal cell, which is expressed as a capacitance in an equivalent circuit, and a voltage drop due to the resistance component of the alignment film occurs. As a result, the voltage applied to the liquid crystal cell decreases, causing the above-mentioned characteristics to shift. If no alignment film is present, this voltage drop does not occur, so it is understood that the above-mentioned shift does not occur. Conventional liquid crystal display devices have the above-mentioned problems, so
There are problems of occurrence of crosstalk and reduction of contrast, and these problems become more serious when the duty ratio is reduced in order to perform large-capacity display. The present invention attempts to solve such problems based on the above study results, and the present invention aims to solve such problems based on the above study results.
The purpose is to eliminate structural fluctuation factors of liquid crystal display devices. [Means for Solving the Problems] The present invention provides that striped transparent electrodes are arranged in directions orthogonal to each other on each of the opposing surfaces of a pair of insulating substrates that sandwich a liquid crystal, and an alignment film is provided thereon. In this structure, predetermined ions were implanted into the upper part of the transparent electrode of the alignment film to lower the resistance of the alignment film in the liquid crystal cell portion. [Function] By implanting predetermined ions into the alignment film to lower the resistance value of the alignment film, the voltage drop across the alignment film when turned on becomes smaller, so the voltage applied to the liquid crystal increases. Therefore, when a voltage with a smooth waveform is applied, a shift in brightness characteristics with respect to voltage can be eliminated. Therefore, even if the duty ratio is reduced, crosstalk is reduced, contrast is improved, and large-capacity display with high display quality is possible. [Example] An example of the present invention will be described below with reference to FIG. 1, along with a manufacturing method thereof.

[See FIGS. 1(al) and (b)] First, a transparent electrode 3 made of a transparent conductive film such as ITO is placed on the surface of a pair of insulating substrates 1°2 such as glass substrates.
After forming it into a stripe shape and applying it to a thickness of about 500 mm using polyacetylene as an alignment agent,
The alignment film 4 is formed by firing at a temperature of 0°C.

[See Figures (C1 and (d))] Next, as shown by arrows in the figure, Na+ ions are selectively implanted into the alignment film 4. The ion implantation is carried out only directly above the electrode 3. When implanting ions in this step, the ion acceleration voltage is approximately 100 KeV, and the dose is approximately 1X per 1 cm.
The number was 1016 pieces. The hatched area in the figure indicates the region into which ions were implanted.

[See (0) in the same figure] Next, both substrates 1.2 are placed facing each other with the alignment film 4 inside, and the liquid crystal 5 is sealed between them. In this example, ions were implanted only directly above the transparent electrodes 3 because if ions were implanted over the entire alignment film 4, there was a risk that the transparent electrodes 3 would become electrically conductive. In this way, the alignment film resistance of the liquid crystal cell portion can be lowered. It goes without saying that after the ion implantation is completed, the alignment film 4 is subjected to rubbing treatment as usual. In this way, the 6
4 (IX400 dots, thickness 6.8 μm liquid crystal panel was manufactured.As liquid crystal 5, FA4 manufactured by Chisso Corporation was manufactured.
116 was used. When evaluating the display quality using this panel, it was found that both crosstalk and contrast were significantly improved, and the display quality was improved, compared to the case without ion implantation. Note that the resistance of the alignment film is determined by the ion acceleration voltage and Icm
It can be adjusted by changing the number of ions to be implanted per 2 ions. [Effects of the Invention] As described below, according to the present invention, a large capacity display with high display quality and low crosstalk and contrast is possible.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of problems in the conventional technology. In the figure, 1.2 indicates the insulating substrate 3 is a transparent electrode, 4 indicates an alignment film, and 5 indicates a liquid crystal. (Glass substrate)

Claims (1)

[Claims] A pair of insulating substrates sandwiching a liquid crystal, each of the opposing surfaces of the insulating substrates has striped transparent electrodes arranged in directions perpendicular to each other, and an alignment film covering the striped transparent electrodes. , and a liquid crystal display device characterized in that the alignment film is formed by implanting predetermined ions into the upper part of the transparent electrode.