JPH01120531A - Liquid crystal element and its production - Google Patents

Abstract

PURPOSE:To decrease the coloration of a display part generated from a relation between refractive index anisotropy and gap and to obtain a liquid crystal element having wider visual angles by forming fine recesses on the oriented film or underlying layer on a substrate and forming ruggedness on the inside surface side of the substrate. CONSTITUTION:A transparent electrode 13 is formed on the substrate 11 and an orienting agent is coated on the electrode 13. Spherical materials 12 consisting of glass beads are then sprayed thereon and the orienting agent is cured by a heat treatment to form the oriented film 15. This oriented film is subjected to a rubbing treatment to remove the spherical materials 21 and to form the fine recesses 17 on the surface of the film 15. A transparent electrode 14 and an oriented film 16 are formed on the substrate 12. The glass beads as spacers 6 are then sprayed on the substrate 11 and a sealant consisting of a thermosetting resin is screen-printed to the peripheral part of the substrate 12. The substrates 11, 12 are then stuck to each other and thereafter, the resin is cured. An Np liquid crystal is sealed into the spacing between the substrates 11 and 12 to constitute the liquid crystal cell. This cell is sandwiched between polarizing plates 19, 20, by which the liquid crystal element is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention provides a liquid crystal element with less coloring in the display area caused by the relationship between refractive index anisotropy and the gap and with less viewing angle dependence, and a method for manufacturing the same. Regarding.

"Conventional technology" FIG. 6 shows the main parts of a conventional liquid crystal element.

In this liquid crystal element, a liquid crystal layer 1 is sandwiched between two glass substrates 4, 4 each having a transparent layer 711+12 and an alignment film 3, and the outer periphery thereof is sealed with a sealing material 5.
The gap between the glass substrates 4, 4 is regulated by a spacer 6.

In this liquid crystal element, fine irregularities 7 are formed on the inner surface of one glass substrate 4 in order to expand the viewing angle and reduce the coloring of the display area caused by the relationship between the refractive index anisotropy and the gap. It is formed.

The unevenness 7 of this liquid crystal element was formed by chemically etching the glass substrate 4 with hydrofluoric acid or by mechanically grinding.

[Problems to be Solved by the Invention] In the conventional liquid crystal element described above, the unevenness 7 provided on the glass substrate 4 has irregular height differences and periods, and also has steep rises and acute corners. Therefore, there were complaints that the coloring of the display section could not be sufficiently alleviated and the viewing angle could not be sufficiently expanded.

In addition, the conventional manufacturing method described above, in which unevenness is formed by etching the substrate surface with hydrofluoric acid or by mechanical grinding, requires many steps for surface treatment of the substrate, and there is a problem in that the management of the manufacturing process is complicated. Ta.

"Means for Solving the Problems" The liquid crystal element of the first invention has a slight recess formed in the alignment film formed on the substrate or in the underlayer provided between the alignment film and the substrate. It is something that

The base layer is a layer formed of a material with excellent light transmittance and good heat resistance. This underlayer may be provided between the substrate and the alignment film, and may be provided directly under the alignment film or between the substrate and the transparent electrode.

The base layer and the alignment film are formed of a material that is applied to the substrate in a fluid state and then hardened to become the base layer or the alignment film.

As the base agent and alignment agent for forming this base layer or alignment film, it is possible to use a substance that is cured by ultraviolet irradiation, but it is preferable to use a thermosetting substance, especially thermosetting Vit resin.

The recess provided in the alignment film or underlayer is 100 μm.
It seems desirable to form them at intervals of approximately Further, it is considered desirable that the depth of the recess is about 2 to 5 microns.

In the liquid crystal element of the first invention, recesses are provided in the alignment film or the underlying layer (thus, the unevenness is formed on the inner surface of the substrate, so compared to the case where the unevenness is directly provided on the substrate, the height difference and periodicity are It is possible to easily form unevenness that changes more uniformly and smoothly.

Further, in the liquid crystal element of the first invention, when a recess is provided in the base layer, the depth of the recess, that is, the difference in height of the unevenness can be appropriately set depending on the thickness of the base layer.

The manufacturing method of the second invention is a suitable method for manufacturing the liquid crystal element of the first invention. According to this manufacturing method, after applying an alignment film and a pliable alignment agent or a base agent to serve as a base layer on a substrate, a spherical substance is sprinkled on the coated base agent or alignment agent, and then the base agent or alignment agent is The agent is cured, and then the dispersed spherical material is removed.

After the force of the spherical material is removed, a large number of fine recesses are formed in the alignment film or the underlying layer.

Spraying of the spherical material may be carried out immediately after applying the base agent or alignment agent, but if necessary, it may be performed after some time has elapsed and the viscosity of the applied base agent or alignment agent has increased.

Further, it is desirable to scatter the spherical material as precisely as possible. As a result of the densely distributed spherical substances colliding with each other, the density of the recesses formed becomes more uniform.

Furthermore, it is desirable to use a material that does not easily adhere to the base agent or alignment agent and is difficult to break, such as glass or alumina, as the spherical material to be scattered.

To remove the dispersed spherical material, it is possible to use means such as spraying gas or the like onto the spherical material, or scraping it off in a fraudulent manner. Furthermore, when forming fine recesses in the alignment film, the spherical material can be removed at the same time during the rubbing process.

According to the manufacturing method of the second invention, uneven depressions are formed by pressing the sprayed spherical material, so unevenness with more uniform height difference and period is formed on the base layer or alignment film. Ru. In addition, the area around the recess that is formed is
Since the corners are rounded by appropriately adjusting the viscosity of the alignment agent or base agent, the formed unevenness changes smoothly.

Further, in the manufacturing method of the second invention, since the spherical material is removed after the base agent and alignment agent are cured, there is an advantage that clear recesses can be formed in the base layer and alignment film.

"Example" (Example 1) FIG. 1 shows a first example of the liquid crystal element of the first invention. This liquid crystal element is of the TN type, and is numbered 1 in the figure.
1 and 12 are glass substrates, respectively. Transparent electrodes 13 and 14 made of ITO (indium tin oxide) are provided on these substrates 11 and 12, respectively. Further, on the transparent electrode H, 14, an alignment agent Jrt-100 is applied.
(trade name; manufactured by Nitto Denko) alignment films 15° and 16 are provided.

The alignment film 15 provided on one substrate II is provided with a large number of minute recesses 17, and the recesses 17...
・As a result, unevenness is formed on the surface of the alignment film 15. The thickness of the alignment film 15 was a little over 3μ1, the interval between the recesses 17 was about 100μ, and the depth was about 3μ.

The gap between the substrates 11 and 12 is regulated by a spacer 6, and the gap between the two substrates If and 12 is sealed by a sealing material 5. Polarizing plates 19.20 are provided on the outer surfaces of the substrates 11.12.

Next, a method for manufacturing this liquid crystal element will be explained.

First, a transparent electrode 13 was formed by sputtering ITO onto a substrate 11 using a conventional method. Next, the transparent electrode 13 was coated with alignment agent JR-100 using a spinner. Then, on the applied alignment agent, spherical substances 21 each having a diameter of 100 μm were sprinkled as shown in FIG. Glass beads were used as the spherical substance 21. Next, the alignment agent was heat-treated and cured to form an alignment film 15.

Thereafter, the alignment film 15 was subjected to a rubbing treatment, and at the same time, the spherical substances 21 scattered thereon were removed. A large number of fine recesses 17 were formed on the surface of the alignment film 15.

On the other hand, a transparent electrode 14 and an alignment film 16 were formed on the substrate 12 by a conventional method.

Next, on one of the substrates 11, a particle size 1 that will become the spacer 6...
0 μ shoulder glass beads are scattered, a sealing material made of thermosetting resin is screen printed on the periphery of the other substrate 12, the substrates II and 12 are pasted together, and then the thermosetting resin is cured. Ta. Next, Np liquid crystal is sealed in the gap between the substrates 11 and 12 to form a liquid crystal cell, and this cell is attached to the polarizing plate 1.
9.20 and completed the liquid crystal element.

(Embodiment 2) FIG. 3 shows a second embodiment of the liquid crystal element of the first invention.

This liquid crystal element is different from that of the first embodiment in that a base layer 22 is provided between one substrate 11 and the transparent electrode I3, and fine recesses 17 are formed in this base layer 22. It is in the point where it is. The thickness of the base layer 22 is a little over 2 μ1, and the concave i$1
The depth of 7 is a little less than 2μ1, and the interval between recesses 17 is about 10
The shoulder was 0μ.

This base layer 22 is made of a mixed material of silica and thermosetting resin (
It is made of GCM-710 (trade name, manufactured by Japan Synthetic Rubber Co., Ltd.).

Next, I will explain the manufacturing method of this liquid crystal element.

First, GCM manufactured by Japan Synthetic Rubber was applied to one of the substrates 11 using a spinner. Next, spherical material 21... was sealed and sprinkled with glass beads having a diameter of 100 μm on the applied GCM. After that, the GCM was hardened by heat treatment, and then purified air was blown onto the spherical material 2.
1... was removed to form a base layer 22. Fine recesses 17 were formed on the surface of the formed base layer 22.

Next, a transparent mold 1 was formed on this base layer 22 in the same manner as in Example 1.
ii13 was provided, and then an alignment agent JR-100 was applied and baked to form an alignment film 15.

Thereafter, the same processing as in Example 1 was performed to complete the liquid crystal element of the second example.

The surface roughness, viewing angle dependence, and display color of the liquid crystal element of Example 2, the liquid crystal element of Example 2, and the conventional liquid crystal element were examined.

(Surface roughness) The roughness of the surface of the alignment film 15 for the liquid crystal element of the first embodiment, the surface of the base layer 22 for the liquid crystal element of the second embodiment, and the surface roughness of the substrate 4 for the conventional liquid crystal element. Measured by crude juice. The results are shown in Figure 4.

From the results shown in FIG. 4, it was confirmed that the unevenness provided in the liquid crystal element of the present invention changes smoothly and has a substantially uniform period and height difference.

(Viewing angle dependence) The liquid crystal element was set horizontally, and the viewing angle was sequentially changed from the normal direction to observe display quality such as changes in display color and contrast.

The results are shown in Table 1.

Note to Table 1 ○: Display quality is the same as the viewing angle of 0° △: Display quality is lower than the viewing angle of 0° It was found that the viewing angle dependence was further improved.

(Display Color) The display color of the liquid crystal element when the liquid crystal element was irradiated with standard light source C specified by the International Commission on Illumination (CrE) was measured and plotted on an (xy)-chromaticity diagram.

The results are shown in Figure 5.

From the results shown in FIG. 5, it was revealed that the liquid crystal element of the present invention had a display color closer to the light source color and less coloring than the conventional liquid crystal element.

"Effects of the Invention" As explained above, in the liquid crystal element of the first invention, unevenness is formed on the inner surface side of the substrate by forming minute depressions in the alignment film or underlayer provided on the substrate. Therefore, it is possible to form irregularities on the inner surface of the substrate with a uniform period and height difference that change smoothly.

Therefore, according to the first aspect of the invention, it is possible to provide a liquid crystal element in which the display portion is less colored due to the relationship between the refractive index anisotropy and the gap and has a wider viewing angle.

Further, in the manufacturing method of the second invention, after applying an alignment agent to become an alignment film or a base agent to become a base layer on a substrate, a spherical substance is sprinkled on the coated base agent or alignment agent, and then the base agent is applied. Alternatively, since the liquid crystal element is manufactured by curing the alignment agent and then removing the dispersed spherical material, it is possible to efficiently manufacture the liquid crystal element of the first invention with little display coloration and low viewing angle dependence. can.

Furthermore, according to the manufacturing method of the second invention, the unevenness can be formed on the inner surface side of the substrate by an extremely simple process of dispersing the spherical material and then removing the spherical material, thereby simplifying the manufacturing process of the liquid crystal element. It has the advantage of being easy to manage.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of Example 2 of the liquid crystal element of the first invention, FIG. 2 is a cross-sectional view showing the state of the process of manufacturing the liquid crystal element of the same example, and FIG. Second liquid crystal element of the invention
A cross-sectional view showing an example, FIG. 4 is a graph showing the results of measuring the roughness of the uneven surface of the first example, the second example, and a conventional liquid crystal element, and FIG. 5 is a graph showing the display color. An (xy)-chromaticity diagram showing the results of the investigation, and FIG. 6 is a sectional view showing the main parts of a conventional liquid crystal element. DESCRIPTION OF SYMBOLS 11... Substrate, I5... Alignment film, I7... Fine recessed part, 21... Spherical substance, 22... Base layer.

Claims (3)

[Claims] (1) A liquid crystal element characterized in that a large number of minute recesses are formed in an alignment film formed on a substrate or in a base layer provided between the alignment film and the substrate. (2) The liquid crystal wire according to claim 1, wherein the alignment agent or base agent forming the alignment film or base layer is applied in a fluid state and then subjected to a curing treatment. Child. (3) After applying an alignment agent that will become an alignment film or a base agent that will become a base layer on the substrate, a spherical substance is sprinkled on the coated base agent or alignment agent, and then the base agent or alignment agent is hardened. , a method for manufacturing a liquid crystal element, characterized in that the sprayed spherical substance is then removed.