JPH0481817A - ferroelectric liquid crystal panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ferroelectric liquid crystal panel used for liquid crystal display devices, optical gloss, tar, etc.

Conventional technology Conventional liquid crystal panels form a transparent conductive film on a glass substrate, then
After printing and curing a horizontal alignment film made of polyimide, polyvinyl alcohol, etc., a rubbing process was performed, and ferroelectric liquid crystal was injected between these substrates.

Problems to be Solved by the Invention However, in the conventional liquid crystal panel described above, since the liquid crystal molecules are horizontally aligned from the initial state, they are affected by the uniaxial regulating force at the substrate interface due to rubbing, and it is difficult to achieve good bistability. It was difficult to obtain.

The present invention solves the above problems, and aims to provide an excellent ferroelectric liquid crystal panel having good bistability.

Means for Solving the Problems In order to achieve the above object, the present invention provides a structure in which the dielectric anisotropy is strongly negative between a pair of substrates with electrodes, in which an alignment film on at least one of the substrates is subjected to vertical alignment treatment. Filled with dielectric liquid crystal,
A voltage is applied to bring it into a horizontally aligned state.

Effect of the present invention Due to the above-described structure, the liquid crystal in the portion away from the substrate interface is horizontally aligned, but the liquid crystal near the substrate interface is vertically aligned, so it is less susceptible to the effects of uniaxiality due to liquid crystal rubbing. It exhibits bistability.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of an embodiment of the present invention, and as shown in the figure, two substrates 1.8 made of transparent glass or the like are used.
An electrode 2.7 made of a transparent conductive film (ITO III) is formed thereon. After cleaning this glass substrate 1.8, a vertical alignment agent (a 0.3% solution of n-octadecyltriethoxine in isopropyl alcohol) was applied thereon as a vertical alignment film 3.6 using a spinner. A rubbing process is performed using a rubbing cloth made of rayon. Thereafter, SiC2 powder with a diameter of 2 μm is sprinkled as a spacer 9 on the surface of one glass substrate I on which the vertical alignment film 3 is provided, and sealing resin is applied to the edge of the surface of the other glass substrate 8 on which the vertical alignment film 6 is provided. 4 and print both these substrates 1,
8 are attached so that their vertically oriented *36 faces face each other, and the sealing resin 4 is cured by heating. Thereafter, vacuum evacuation is performed, and ferroelectric liquid crystal 5 is injected between the two glass substrates 1 and 8 while being heated. , : After slowly cooling the baffle to room temperature and sealing the injection port, heat it again until the liquid crystal shows a cholesteric phase. 7. Cool slowly to room temperature while applying an alternating electric field of ±IOV・10 . When the liquid crystal panel prepared in this way was observed using a polarizing microscope, it was found that by applying a voltage in the cholesteric phase, the strong taN liquid crystal molecules changed from a vertically aligned state to a horizontally aligned state, resulting in a chiral smear exhibiting ferroelectricity. It was observed that the Cutinok C phase also showed a good horizontal alignment state. FIG. 2(b) shows the transmittance when a voltage waveform as shown in Part 2(a) is applied to this liquid crystal panel and a conventional liquid crystal panel using polyimide for the alignment films of the upper and lower substrates. In the figure, Vk indicates a write pulse, α indicates the transmittance of this embodiment using a vertical alignment agent as the alignment film, and β indicates the transmittance of the conventional example using polyimide as the alignment film.

As is clear from FIGS. 2(a) and 2(b), when polyimide is used as the alignment film, the response time is long and sufficient transmittance is not obtained even during memory operation.

This is thought to be because the binding force of the alignment film on the liquid crystal molecules in the rubbing direction is too strong, making it difficult for the liquid crystal molecules near the substrate interface to move, and also because the liquid crystal molecules return to the rubbing direction during the non-selective pulse period. It will be done. On the other hand, when a vertical alignment agent is used as the alignment films 3 and 6, the molecules of the ferroelectric liquid crystal 5 near the substrate interface are considered to be vertically aligned, so they are less susceptible to the effects of uniaxiality due to rubbing.
Even during the non-selective pulse period, the ferroelectric liquid crystal 5 does not return to the rubbing direction and maintains the memory state, so it exhibits sufficient transmittance.

In this example, both substrates 1 and 8 were subjected to vertical alignment treatment, but this vertical alignment treatment may be applied to only one of substrates 1 or 8, and n as a vertical alignment agent may be used.
- The explanation was given using octadecyltriethoxine run as an example, but if it vertically aligns liquid crystal molecules, DMOAP
It is also possible to use other surfactants such as (N,N dimethyl-N-octadecyl-3-aminopropyltrimethoxysilyl chloride). Further, the vertical alignment films 3 and 6 may be formed after performing the rubbing process.

As described above, according to the above embodiment, the ferroelectric liquid crystal 5 is sealed in the panel and horizontally aligned by applying a voltage in a heated state, so that the transmittance is not easily affected by uniaxiality due to rubbing, and the transmittance is sufficient. This has the effect of being able to obtain the following.

Effects of the Invention As is clear from the above examples, the present invention provides a ferroelectric liquid crystal with negative dielectric anisotropy between a pair of electrode-attached substrates in which an alignment film on at least one substrate is subjected to vertical alignment treatment. is encapsulated and placed in a horizontally aligned state by applying a voltage.
A liquid crystal panel exhibiting good bistability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a ferroelectric liquid crystal panel in an embodiment of the present invention, FIG. 2(a) is a voltage waveform diagram applied to the liquid crystal panel, and FIG. 2(b) is a diagram of the voltage waveform applied to the liquid crystal panel. FIG. 3 is a characteristic diagram showing the relationship between response time and transmittance. l8...Substrate, 2゜7...Electrode, 6...Vertical alignment film, 5...Ferroelectric liquid crystal.

Claims (2)

[Claims] (1) A ferroelectric liquid crystal with negative dielectric constant anisotropy is sealed between a pair of electrode-attached substrates in which the alignment film on at least one substrate has been subjected to vertical alignment treatment, and a voltage is applied to bring it into horizontal alignment. Ferroelectric liquid crystal panel. (2) Claim 1 wherein the ferroelectric liquid crystal is in a cholesteric phase.
The described ferroelectric liquid crystal panel.