JPS61215521A - Production of liquid crystal apparatus - Google Patents

Abstract

PURPOSE:To obtain the titled apparatus having an excellent display quality by using a photosensitive polyimide as a spacer material, thereby making <=3mum a thickness of the liquid crystal layer and making an uniformity and ensuring a high rate responsibility and a bistability of the titled apparatus. CONSTITUTION:The liquid crystal apparatus having an optical modulation system is produced by arranging a transparent electrodes 4, 5 and an orientated film 6, 7 performed the orientation treatment on each facing surfaces of the two electrodes 2, 3, and adhering under a pressure each other through a sealing material 9, and enclosing a ferroelectricity chiral smectic liquid crystal 10 in a cell space limitted by the sealing material 9. The spacer 8 is formed on the electrode substrate 3 by a pattern forming method. The thickness (d) of the liquid crystal layer between the electrode substrates 2, 3 is limitted by the spacer 8. The spacer 8 composes of the photosensitive polyimide high molecular film. The photosensitive polyimide material is preferably a photosensitive polymer obtd. by reacting a diamine compd. having a photosensitive group in a molecule and a tetracarboxylic acid anhydride. The photosensitive polyimide high molecular film is formed on a whole surface of the electrode substrate 3, and then optically cured an optical polyimide film by irradiating a light.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to, for example, a light modulation type liquid crystal device in which a liquid crystal having ferroelectricity is sealed. Concerning how to send money.

Gastric San technology Conventional display devices using liquid crystals include twist
The nematic field effect type is common, and is widely used in electronic desktop calculators, digital watches, etc. However, despite improvements in liquid crystal materials, cells, driving methods, etc., it lacks high-speed response, and its response is difficult to achieve when used in TV image displays, portable combinator display devices, and optical shutter devices, which have recently been attracting attention. There was a problem with sexuality.

In order to solve this problem regarding responsiveness, light modulation display devices using ferroelectric chiral smectic liquid crystals have been used, but it is generally difficult to obtain the memory properties that are characteristic of such ferroelectric liquid crystal materials. In order to achieve this, it is necessary to ensure a thickness of the liquid crystal layer of 1 to 3 μm. However, as spacers that define the thickness of the liquid crystal layer, glass fiber, toughened alumina powder, glass and plastic beads, etc. have been conventionally used, and such spacers usually have a thickness of 5μ or more, and do not meet the desired thickness. 1~3μ
It has not been easy to maintain a uniform thickness of the liquid crystal layer due to the inability to obtain dimensions of - and variations in spacer dimensions.

Problems to be Solved by the Invention In summary, especially in light modulation type display devices using ferroelectric liquid crystal materials, conventional spacers cannot ensure the thickness of the liquid crystal layer to be 3μ or less; Unable to maintain uniform thickness.

Therefore, it was not possible to ensure high-speed response and bistability.

The purpose of the present invention is to solve the above-mentioned technical problems, reduce the thickness of the liquid crystal layer to 3μ or less, and make the thickness uniform to ensure high-speed response and bistability, thereby improving display quality. An object of the present invention is to provide a method for manufacturing a liquid crystal device that can achieve the following objectives.

Means for Solving the Problems The present invention forms a spacer made of photosensitive polyimide on the surface of at least one of a pair of electrode substrates facing each other, and defines a space between the electrode substrates by the spacer. This is a method for manufacturing a liquid crystal device characterized in that a liquid crystal is sealed in a space.

According to the present invention, by using photosensitive polyimide as the material of the spacer, the thickness of the liquid crystal layer can be secured to 3μ or less, and the accuracy of the thickness can be improved. I can do it.

Embodiment FIG. 1 is a sectional view of a liquid crystal device 1 according to the present invention. A light modulation type liquid crystal device 1 has transparent electrodes 4 and 5 and alignment films 6 and 7 that have been subjected to an alignment process disposed on mutually opposing surfaces of two electrode substrates 2 and 3, and is arranged with a sealing material 9 in between. The cell space is defined by the sealing material 9 and the dielectric smectic liquid crystal 10 is sealed in the cell space defined by the sealing material 9.

A spacer 8 is patterned on one electrode substrate 3, and the thickness d of the liquid crystal layer between the electrode substrates 2 and 3 is defined by this spacer 8. A pair of polarizers 11 and 12 are arranged on both external sides of the transparent substrates 2 and 3,
By applying and releasing a predetermined voltage to the upper and lower transparent electrodes 4.5, a light shutter function can be achieved, for example.

Referring to FIG. 2, the molecules 10a of the ferroelectric chiral smectic liquid crystal 10 have a helical structure arranged at a tilt angle θ with respect to the helical axis direction indicated by the arrow a. . The liquid crystal molecules 10a have spontaneous polarization in a direction perpendicular to each molecule. Now, when an electric field E equal to or higher than a certain critical electric field is applied to the upper and lower electrode substrates 2 and 3, the helical structure of the liquid crystal molecules 10m is dissolved, and the liquid crystal molecules 10a all point in the same direction. Since the alignment is due to spontaneous polarization, the liquid crystal molecules 10m have two alignment directions depending on the calculation directions E and -H.The liquid crystal molecules 10m have a long and narrow shape, and are birefringent with different refractive indexes in the long axis direction and the short axis direction. Polarizers 11 are placed above and below the electrode substrate 2°3 to show the
．． By arranging 12 orthogonally, it is possible to obtain an optical modulation device that performs switching based on electric field polarity. This change in the arrangement of the liquid crystal molecules 10m only changes the orientation of the molecules within the layer, so it is not accompanied by a change in the layer W# structure as in the Twisted Y-Wintermatic field effect type, and therefore provides a high-speed response. It is something that has a nature.

Furthermore, even in a steady state where no electric field is applied, it is possible to eliminate the helix by making the thickness d of the liquid crystal layer thinner than the helical pitch of 10 m of liquid crystal molecules. In this case as well, the liquid crystal molecules 10a exhibit two alignment directions and exhibit bistability. However, if an electric field E is applied, all the liquid crystal molecules 10m become aligned with the tilt angle θ with respect to the helical axis direction a, resulting in a bistable orientation as shown in Figure 2 (2). can be obtained, but this state continues to be maintained even when the electric field is turned off. On the other hand, the electric field −E
is applied, all liquid crystal molecules 10a move in the helical axis direction a
The molecular arrangement is tilted by the tilt angle −θ,
A stable orientation as shown in FIG. 2(2) can be obtained, and this state continues to be maintained even when the electric field is turned off. In this way, by reducing the thickness d of the liquid crystal layer, high-speed response and bistability can be obtained at the same time.

The optical modulation method using the above birefringence phenomenon is shown in Figure 2 (
The relationship between the incident light intensity Io and the transmitted light intensity I in 2) is
The relationship in Figure 2 (3) is expressed by the second equation.
It is shown by the formula.

I=O...(1) I=(I o/2)・(S 1n24θ)・(S
in2g −(Δn・d/in) ) ・・
・(2) Here, Δn represents the refractive index anisotropy of the ferroelectric chiral smectic liquid crystal 10, d represents the thickness of the ferroelectric chiral smectic liquid crystal layer, and θ represents the ferroelectric chiral smectic liquid crystal layer. Represents 10 helical tilt angles.

The state shown in Fig. 2 (2) is
The profile for the case of e, 550ne+ and V650n- is shown in Figure 3, and θ=
It is clear that the transmitted light intensity ■ when π/8 is strongly dependent on Δn−d and the wavelength ^. Therefore, in the visible light wavelength region, Δn-d needs to be set in the range of 0.2 to 0.3, which makes it possible to obtain a good display element without coloring. Further, since the refractive index anisotropy Δn of the ferroelectric smectic liquid crystal 10 is generally about 0.1 to 0.2, the optimal value for the thickness d of the liquid crystal layer is 1 to 3 μ-. In addition, in order to obtain a bistable state, the value of the thickness d of the liquid crystal layer must be smaller than the helical pitch of the ferroelectric smecti liquid crystal 10, and from this point of view, the thickness of the liquid crystal layer must be It is understood that it is appropriate to choose d between 1 and 3 .mu.-.

An example of the ferroelectric liquid crystal 10 is as follows:
As shown in table #41.

(The following is a margin.) FIG. 4 is a sectional view taken along the section line ff-IV in FIG. 1. On the electrode substrate 3, there is a 3μ-
A number of spacers 8 having the following uniform thickness are formed. The thickness of the spacer 8 defines the thickness d of the liquid crystal layer.

The spacer 8 is made of a photosensitive polyimide polymer film.

A suitable material for this photosensitive polyimide is, for example, a photosensitive polymer obtained by reacting a diamine compound having a photosensitive group in its molecule with a tetracarboxylic anhydride.

To pattern the spacers 8, first, a polymer film made of photosensitive polyimide is coated over the entire surface of one electrode substrate 3 by a spinner coating method or a roll coater method. form. The thickness of this polyimide film is in the range of 1 to 3 μ-.The polyimide film is photocured at any position by irradiation with light.The remaining portion of the polyimide film other than the photocured portion is removed. As shown in FIG. 4, a plurality of dot-shaped polyimide films having a uniform thickness of 3 μm or less are formed.

After patterning the spacers 8 made of a photosensitive polyimide film on the electrode substrate 3 in this way, the alignment film 7 is subjected to an alignment process, and an epoxy adhesive is applied to the outer edge 13 of the alignment film 7 over the entire circumference in the circumferential direction. A sealing material 9 such as the following is applied.

Thereafter, it is stacked on the other electrode substrate 2 that has been subjected to the alignment treatment and adhered to each other using a sealing material 9 to form a cell space, and a ferroelectric chiral smectic liquid crystal 10 is sealed in the cell space. The thickness d of this liquid crystal layer is
Since the thickness is equal to the thickness of the spacer 8 and uniformly 3 μm or less, the high-speed response and bistability of the ferroelectric smectic liquid crystal 10 are ensured. Therefore, a light modulation type liquid crystal device with excellent display quality can be obtained.

The shape of the spacer 8 is not limited to the dot shape as described above, but may be a longitudinal shape extending in the longitudinal direction.
In addition, the number, shape, and arrangement pattern of the spacers 8 can be arbitrarily selected depending on the mode of light irradiation to the photosensitive polyimide film, so it is possible to design and change the design according to the type of liquid crystal cell very smoothly. .

In the above-described embodiment, the spacer 8 made of photosensitive polyimide is used in a light modulation type liquid crystal device using ferroelectric smectic liquid crystal; It may also be configured to be used in a liquid crystal device.

Effects As described above, according to the present invention, by using photosensitive polyimide as the material of the spacer, the thickness of the liquid crystal layer can be made uniform to 3 μm or less. Therefore, high-speed response and bistability are ensured, and a liquid crystal device with excellent display quality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a liquid crystal device 1 according to the present invention, FIG. 2 is a diagram schematically showing 10 m of liquid crystal molecules, and FIG.
Transmitted light intensity l of IL type Kaiful Smectic liquid crystal 10
FIG. 4 is a cross-sectional view of the electrode substrate 3 on which spacers 8 are provided. 1... Liquid crystal device, 2, 3... Electrode substrate, 4, 5...
・Transparent electrode, 8... Spacer, 10... Ferroelectric chiral smectic liquid crystal

Claims (1)

[Claims] A spacer made of photosensitive polyimide is formed on the surface of at least one of a pair of electrode substrates facing each other, a space between the electrode substrates is defined by the spacer, and a liquid crystal is sealed within this space. A method for manufacturing a liquid crystal device.