JPH0534669A - Polymer dispersion type liquid crystal display device - Google Patents

Abstract

PURPOSE:To miniaturize the display device constituted by combining a polymer dispersion type liquid crystal display element and louvers by reducing the thickness over the entire part thereof and to attain higher efficiency by eliminating the light loss by the reflection at the boundary between the liquid crystal display element and the louver member. CONSTITUTION:This display device is constituted of the liquid crystal display element constituted by interposing the louver parts 13a between counter electrode substrates 11 and 12 and packing a liquid crystal part 15 formed by microcapsulating a liquid crystal material and dispersing and holding the capsules into a polymer matrix into the spacings of the louver parts 13a and a rear surface light source body (EL lamp). The liquid crystals in the capsules array orderly in the parts impressed with an electric field. The liquid crystals array disorderly in the parts not impressed with the electric field. The light transmitted through the orderly arraying liquid crystal parts advances rectlinearly as it is. This light is absorbed on the wall surfaces of the louver parts and is admitted dark without emitting to the front surface side. The incident light scatters in the disorderly arraying liquid crystal parts and, therefore, the light which is not absorbed in the louver parts emits to the front surface side and is eventually admitted bright.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using a polymer dispersion type liquid crystal display device in which liquid crystals are microcapsules (small spheres) in a polymer matrix and dispersed and held.

[0002]

2. Description of the Related Art In a polymer dispersion type liquid crystal display device in which liquid crystal is dispersed and held in a polymer matrix, the scattering and transmission of light incident on the liquid crystal display device can be controlled by an electric field effect, and the liquid crystal is sealed between substrates. Since it is easy to increase the area as compared with a liquid crystal cell type display element, its application range is wide not only for displays but also for light control such as lighting adjustment of windows, and it is currently attracting attention. .

The liquid crystal used in the above-mentioned liquid crystal display device is mainly a nematic liquid crystal (in addition to this, a liquid crystal such as a cholestic liquid crystal or a smectic liquid crystal is also possible), which has a structure in which this liquid crystal is dispersed and held in a polymer matrix. The specific structure thereof is determined by the materials of the matrix and the liquid crystal, the conditions for forming the element, etc., and various kinds are known at present.

For example, as shown in Japanese Patent Publication No. 58-501631, etc., polyvinyl alcohol (PVA), which is a polymer having a hydroxyl group, is used as a matrix, and nematic liquid crystal (Δε> 0) is used as a dispersion medium in water. As a means for emulsifying and forming an emulsion, liquid crystal is microencapsulated in PVA and held. Further, Japanese Patent Laid-Open No. 60-252687 discloses a means of using latex as a matrix and emulsifying the liquid crystal with the latex in water to form an emulsion, and as a result, obtaining latex-incorporated liquid crystal.
Further, Japanese Patent Publication No. 61-502128 discloses a means for dispersing and retaining liquid crystal microdroplets by a phase separation method using an epoxy resin as a matrix.

As a display device using this liquid crystal display element, a device combined with a louver is known. Specifically, as shown in U.S. Pat. No. 4,591,233, a louver member is arranged on the back surface of a sheet-like liquid crystal display element, and a light source is arranged on the back surface of the louver member. Light that travels straight from the body to the front side is blocked by the louver member, so when the microcapsule-shaped liquid crystals are aligned (electric field is applied), the incident light travels straight and becomes a dark color display. In the aligned state (state in which no electric field is applied), incident light is scattered and displayed brightly on the front side. Therefore, a desired bright / dark display is performed by selectively energizing the counter electrode of the liquid crystal display element.

[0006]

In the liquid crystal display device using the above-mentioned louver, since the louver member has a structure in which the sheet-shaped liquid crystal display device is laminated, the entire structure becomes thicker, and the liquid crystal display device is further increased. Reflection occurs at the interface between the louver member and the louver member, resulting in a large amount of light loss and inefficiency. In addition, as for the back light source, the entire display device is thickened in a normal lighting device, and unevenness in display brightness is likely to occur. Therefore, the present invention proposes a liquid crystal display device which can be made very thin as a whole.

[0007]

In a polymer dispersion type liquid crystal display device according to the present invention, a louver portion is interposed between counter electrode substrates, and a liquid crystal material is microencapsulated in a gap between the louver portions to form a polymer matrix. It is characterized by comprising a liquid crystal display element filled with a liquid crystal part which is dispersed and held, and a back light source body provided on the back surface of the liquid crystal element. Further, particularly in the above-mentioned display measure, an EL lamp is adopted as a back light source.

[0008]

In the liquid crystal display element, the liquid crystal in the capsule is aligned at the electric field application portion, and the liquid crystal in the capsule is not aligned at the electric field non-application portion. Therefore, the light from the back light source unit arranged on the back surface of the liquid crystal display element is absorbed by the louver wall surface except for the obliquely emitted light, and the light passing through the aligned liquid crystal portions goes straight on. ,
It does not appear on the front side and is dark. Further, since the incident light is scattered in the non-aligned liquid crystal portion, the light not absorbed by the louver portion is emitted to the front side and is recognized brightly. Therefore, by selectively energizing the counter electrode, a desired bright / dark display is performed.

[0009]

EXAMPLES Next, examples of the present invention will be described. The liquid crystal display device according to the present invention includes a liquid crystal display element 1 and a back light source body 2.
The liquid crystal display element 1 will be described in accordance with its manufacturing process. The transparent electrode (ITO) 12 is formed on the transparent substrate 11, and the photosensitive resin 13 is applied thereon (FIG. 1: a).
Next, masking 1 corresponding to the shape of the louver portion 13a
4 is applied, and light is obliquely irradiated to expose the photosensitive resin 13 to light (FIG. 1: b). Further, after the photosensitive resin 13 has been photosensitized, the masking 14 is removed, the exposed portion or the non-exposed portion is etched, and the side surface of the residual resin is blackened after the etching to form the louver portion 13a (FIG. 1: c). ). When the louver portion 13a is formed, liquid crystal 5 is added to the matrix polymer separately and stirred, and the liquid crystal portion 5 is filled in the gap of the louver portion 13a and solidified, and then the substrate 11 having the ITO 12 is laminated to form the element 1. (FIG. 1: d). The display device is the element 1
The back light source body 2 formed of an EL lamp is laminated on the back side of the.

The display drive of the display device is performed by turning on the rear light source 2 and selectively energizing the ITO 12.
The emission of the white light of the back light source 2 to the front side is performed by the louver portion 13a as a light-shielding function and the capsule liquid crystal 1 of the liquid crystal display element 1.
It is determined by the action of the transmitted light of 51. Specifically, as shown in FIG. 2, the capsule liquid crystal 151 in the electric field application portion (ON portion) is aligned, and the incident straight-ahead light is absorbed by the louver portion 13a as it is and does not exit the surface side of the liquid crystal display element 1. Since the capsule liquid crystal 151 is in a non-aligned state in the electric field non-applied portion (OFF portion), the incident light does not go straight but becomes scattered light, and is emitted to the surface side. Therefore, as shown in FIG. 3, bright and dark display is performed by the electric field application portion of the liquid crystal display element 1, and predetermined display is performed by selectively energizing the counter electrode.

In the above-mentioned embodiment, an EL lamp is adopted as the rear light source body 2. Especially, by adopting this EL lamp, there is an advantage that the entire apparatus becomes thin and no unevenness occurs. The present invention is not limited to the above-mentioned embodiment, but at least the louver portion may be included in the display element, the manufacturing means thereof is arbitrary, and the rear light source is also limited to the EL lamp. Alternatively, any illumination mechanism may be adopted as long as it emits visible light.

[0012]

As described above, according to the present invention, in the polymer dispersion type liquid crystal display device, in particular, the louver portion is internally provided in the display element, and the capsule liquid crystal is filled and held by the polymatrix in the gap of the louver portion. Since the entire device can be formed thin and the interface between the louver portion and the liquid crystal display element does not exist, the light efficiency is also improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a liquid crystal display in an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of the liquid crystal display element.

FIG. 3 is an explanatory diagram of an operation of the device.

[Explanation of symbols]

1 Liquid crystal display element 11 board 12 Counter electrode (ITO) 13 Photosensitive resin 13a Louver part 14 Masking section 15 LCD 151 LCD capsule 2 Rear light source (EL lamp)

Claims (2)

[Claims] 1. A liquid crystal display element comprising a louver portion interposed between counter electrode substrates, and a liquid crystal portion filled with a liquid crystal material in which a liquid crystal material is microencapsulated and dispersed and held in a polymer matrix in a gap between the louver portions, and the liquid crystal. A polymer dispersion type liquid crystal display device comprising a back light source body provided on the back surface of an element. 2. The polymer dispersion type liquid crystal display device according to claim 1, wherein an EL lamp is adopted as a back light source.