JPH08179284A - Liquid crystal panel, production of liquid crystal panel and projection device - Google Patents

Abstract

PURPOSE: To provide a liquid crystal panel capable of obtaining sufficient transmissivity at the time of impressing voltage and high in contrast by using a microcapsule as a spacer for holding the gap between substrates of the liquid crystal panel. CONSTITUTION: Transparent conductive films (ITO film) 2, 6 are provided on two transparent glass substrates 1, 7. The spherical microcapsules having 13μm diameter is scattered on one of the glass substrates 1 as the spacer after the glass substrates 1, 7 are cleaned. After that, a sealing resin 5 is printed on the edge part of another substrate and both substrates 1, 7 are laminated and heated to cure the sealing resin 5. After that, a mixture of the liquid crystal 3, a photosetting resin 4 with a photosetting initiator is poured between the substrates 1, 7. Since the liquid crystals in the microcapsules are arrayed in the electric field direction like the outside liquid crystal at the time of impressing voltage by using the microcapsules as the spacer in this way, the transmissivity at the part of the spacer 8 is also increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel used for a liquid crystal display device or an optical shutter, a method for manufacturing the liquid crystal panel, and a projection device.

[0002]

2. Description of the Related Art A liquid crystal panel is thin, lightweight, and can be driven at a low voltage because of its advantages such as a wristwatch, an electronic desk calculator, and a computer.
Sonar computer, personal word processor
It is used for. But currently used TN
(Twisted nematic) type LCD panel and STN
Since a (super twisted nematic) type liquid crystal panel requires a polarizing plate, it has a poor transmittance and a poor light resistance. On the other hand, polymer dispersed liquid crystal (PDLC)
The panel does not have the above-mentioned drawbacks because a polarizing plate is unnecessary.

FIG. 4 shows a sectional view of an example of a conventional polymer dispersion type liquid crystal panel. The figure (a) shows the state when no voltage is applied, and the figure (b) shows the state when voltage is applied. In the figure, 1 and 7 are glass substrates, 2 and 6 are electrodes formed on the glass substrates 1 and 7, 3 is a liquid crystal, and 4 is a photocurable resin.

The polymer-dispersed liquid crystal panel having the above-mentioned structure is such that the liquid crystal is dispersed and held in the resin matrix between the glass substrates with electrodes, or the resin matrix is in the form of particles or network in the liquid crystal. As shown in FIG. 4 (a), when no voltage is applied, the molecules of the liquid crystal 3 are oriented in random directions, so that there is a difference in the refractive index between the resin 4 and the liquid crystal 3. Occurs, the light is scattered,
When a voltage is applied, as shown in FIG. 4B, the molecules of the liquid crystal 3 are aligned in the direction of the electric field, and the liquid crystal 3 and the resin 4 have the same refractive index, so that light is transmitted. It utilizes the phenomenon. The spacer 8 supporting both glass substrates 1 and 7 is a spherical insulator, specifically SiO 2.
₂ and benzoguanamine / melamine resin were used.

[0005]

However, since the conventional spacers do not transmit light, when used in a projection type panel, only the spacer portion is higher than other display portions when a voltage is applied. However, there is a drawback that the transmittance is lowered.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a liquid crystal panel having a high contrast and a method of manufacturing the liquid crystal panel and a projection apparatus which can obtain a sufficient transmittance when a voltage is applied.

[0007]

A liquid crystal panel according to the present invention is a space for maintaining a space between substrates of a liquid crystal panel in which a liquid crystal or a liquid crystal resin composite is sandwiched between a pair of substrates with electrodes.
Microcapsules are used as the server.

[0008]

According to the liquid crystal panel of the present invention, the microcapsules are used as spacers for keeping the distance between the substrates so that the liquid crystal inside the microcapsules is aligned in the direction of the electric field when a voltage is applied, like the liquid crystal outside the microcapsules. Therefore, since the transmittance of the spacer portion also increases, a good display with high contrast can be obtained.

[0009]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In this liquid crystal panel manufacturing method, as shown in FIG. 1, transparent conductive films (ITO films) 2 and 6 are formed on two transparent glass substrates 1 and 7. This glass substrate 1,
After cleaning No. 7, spherical microcapsules having a diameter of 13 μm were sprayed as spacers 8 on one glass substrate 1. As a method of microencapsulation, an aqueous solution of gum arabic at 55 ° C. and an aqueous solution of gelatin at 55 ° C. are prepared,
E-7 (manufactured by BDH) as a liquid crystal was added to an aqueous solution of gum arabic and emulsified. After the gelatin aqueous solution was added to the emulsion thus produced with stirring, the pH was adjusted to 4.5 with hydrochloric acid, and formaldehyde was added to the emulsion while adjusting the pH to 9.0 with sodium hydroxide solution. An encapsulated gelatin-gum arabic complex was obtained.

After that, the edge of the other glass substrate 7 is shielded.
The seal resin 5 is printed, both of the glass substrates 1 and 7 are attached, and heated to cure the seal resin 5.

Thereafter, the liquid crystal 3 is placed between the glass substrates 1 and 7.
E-7 (manufactured by BDH) as 80 (which later becomes small droplets)
wt%, 1.8 wt% of polyester acrylate as a photocurable resin (ultraviolet curable resin) 4 and 18 wt% of 2-ethylhexyl acrylate, and Darocur-1173 (manufactured by Merck) as a photocuring initiator. Of 0.2 wt% was injected.

After injection, the liquid crystal panel is exposed to ultraviolet rays of 50 mw / cm ²
The liquid crystal 3 (which will later become small droplets) is phase-separated from the photo-curable resin 4 by irradiating the liquid crystal for 5 minutes to form a state in which the liquid crystal 3 droplets are dispersed in the photo-curable resin 4 and at the same time the photo-curable resin 4 is dispersed. After curing the resin 4, Loctite 352A is used as a sealing resin in the injection port.
(Manufactured by Nippon Loctite) was applied, the display area was shielded from light so that the display area was not exposed to light, and the sealing resin was cured by irradiating only the sealing portion with ultraviolet rays at 55 mw / cm ² for 90 seconds. For comparison, the spacer 8 is made of SiO 2.
A liquid crystal panel in which _two particles were sprayed was also produced.

A projection device shown in FIG. 2 has been developed using these liquid crystal panels. As shown in FIG. 2, the light emitted from the light source 11 (metal halide lamp) passes through the UV / IR cut filter-12, and then the dichroic mirror-13.
Blue, green and red are separated by a, 13b and 13c, respectively, and are incident on the liquid crystal panel 14a, 14b and 14c. After that, through the lenses 15a, 15b, 15c and the apertures 16a, 16b, 16c, the projection lens system 17
It is incident on a, 17b, and 17c. A drive circuit (not shown) is connected to the liquid crystal panel. When an image was projected using this device, display unevenness was observed in the liquid crystal panel in which SiO ₂ particles were dispersed as a spacer because the transmittance of the spacer portion was lowered when a voltage was applied. On the other hand, in the case where the microcapsule is used as the spacer, the liquid crystal in the microcapsule is aligned in the electric field direction like the liquid crystal outside the microcapsule when a voltage is applied.
A high contrast liquid crystal panel showing sufficient transmittance was obtained. When microcapsules are used as spacers in FIG. 3 (when no voltage is applied (a) and when voltage is applied (b))
Shows the operating state of.

(Embodiment 2) By applying pressure to a liquid crystal panel using the liquid crystal microcapsules produced by the first embodiment as a spacer to break the microcapsules,
The liquid crystal enclosed inside diffused into the panel. As a result, a liquid crystal panel without a spacer was obtained, and a liquid crystal panel showing a uniform display was obtained.

(Example 3) Instead of the microcapsules produced according to the first example, the same resin as the resin of the liquid crystal resin composite and liquid crystal E-7 (BDH) were used in the microcapsules.
Microcapsules encapsulating a mixture of the same) were used.
After the liquid crystal panel was produced, pressure was applied to the liquid crystal panel to break the microcapsules, so that the liquid crystal and resin enclosed therein were diffused into the panel. After that, the liquid crystal (which will become small droplets later) and the photo-curable resin are phase-separated by irradiating with ultraviolet rays to make the liquid crystal droplets dispersed in the photo-curable resin and at the same time cure the photo-curable resin. did. As a result, a liquid crystal panel without a spacer was obtained, and a liquid crystal panel showing a uniform display was obtained.

In the present invention, a mixture of polyester acrylate and 2-ethylhexyl acrylate was used as the photocurable resin, but 2-hydroxyethyl acrylate was used.
Or trimethylolpropane triacrylate, etc., and not only photocurable resin but also thermosetting resin or thermoplastic resin may be used for the reaction by heat. Regarding liquid crystal, E-8 (BDH) and ZLI4792
(Merck KK) or TL202 (Merck KK) may be used, and the polymerization initiator may also be Irgacure 184 (Ciba-Gaigi) or Irgacure 651 (Ciba-Gaigi). That is, the present invention is effective regardless of the liquid crystal material or the resin material.

Alternatively, an active matrix substrate in which an active element is provided on one of the electrode substrates may be used. Further, a method of using a spacer made of polymer dispersed liquid crystal has been devised (Japanese Patent Laid-Open No. 165016/1993). However, in a spacer made of polymer dispersed liquid crystal, liquid crystal droplets are dispersed in a polymer. It is a retained spacer, and the microcapsules of the present invention are totally different in that the encapsulated substance therein is liquid crystal only or a mixture of liquid crystal and resin (uncured).

[0019]

According to the liquid crystal panel of the present invention, a microcapsule is used as a spacer for maintaining a space between substrates of a liquid crystal panel in which a liquid crystal or a liquid crystal resin composite is sandwiched between a pair of substrates with electrodes. As a result, it is possible to obtain a liquid crystal panel with a high contrast that can obtain a sufficient transmittance when a voltage is applied.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a liquid crystal panel according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of a projection device according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing this operating state. FIG. 3A is a sectional view showing a state of the liquid crystal panel in the first embodiment of the present invention when no voltage is applied. FIG. 3B is a sectional view showing a state of applying voltage.

FIG. 4A is a cross-sectional view showing a conventional polymer-dispersed liquid crystal panel when no voltage is applied. FIG. 4B is a cross-sectional view showing a condition when a voltage is applied.

[Explanation of symbols]

 1, 7 Glass substrate 2, 6 Electrode 3 Liquid crystal 4 Photocurable resin 5 Seal resin 8 Spacer 11 Light source 12 UV / IR cut filter 13a, 13b, 13c Dichroic mirror 14a, 14b, 14c Liquid crystal Panel 15a, 15b, 15c Lens 16a, 16b, 16c Aperture 17a, 17b, 17c Projection lens system

Claims (7)

[Claims] 1. A liquid crystal panel characterized by using microcapsules as a spacer for maintaining a space between substrates of a liquid crystal panel in which a liquid crystal or a liquid crystal resin composite is sandwiched between a pair of substrates with electrodes. 2. The liquid crystal panel according to claim 1, wherein the substance encapsulated in the microcapsules is liquid crystal or a mixture of liquid crystal and resin. 3. A spacer for maintaining a space between a pair of substrates with electrodes.
A microcapsule is installed between the two substrates as a server, and a liquid crystal and a resin or a mixture of the liquid crystal and the resin is sandwiched between the two substrates, and phase separation of the liquid crystal and the resin is performed by light irradiation or heating. A method for manufacturing a liquid crystal panel, which comprises: 4. The method for manufacturing a liquid crystal panel according to claim 3, wherein the substance enclosed in the microcapsules is liquid crystal or a mixture of liquid crystal and resin. 5. A spacer for maintaining a space between a pair of substrates with electrodes.
A microcapsule is installed between the two substrates as a server, and a liquid crystal and a resin or a mixture of the liquid crystal and the resin is sandwiched between the two substrates, and phase separation of the liquid crystal and the resin is performed by light irradiation or heating. After performing the
A method for manufacturing a liquid crystal panel, characterized by destroying a server. 6. The method of manufacturing a liquid crystal panel according to claim 5, wherein the substance encapsulated in the microcapsules is liquid crystal or a mixture of liquid crystal and resin. 7. A projection apparatus comprising: the liquid crystal panel according to claim 1 or 2, a light generating means, a drive circuit for applying a signal to the liquid crystal panel, and an optical component for projecting light. .