JPH09292502A - Flat type micro lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high numerical aperture by using a transparent resin material having thiol or sulfide bonds to fill recesses on the substrate surface. SOLUTION: Plural recessed parts 7 having the shape of almost a part of sphere or cylinder are arranged in one dimension or two dimensions on the surface of a substrate 6 consisting of a quartz glass or low expansion crystalline glass. These recessed parts 7 are filled with a transparent resin material 8 having a refractive index higher than that of the substrate so that the inside of the recessed parts 7 acts as a convex lens or a lenticular lens. The transparent resin material has thiol (R-S-H) or sulfide bonds (R-S-R'), wherein R, and R' are hydrocarbon groups. The hydrocarbon groups are preferably phenyl groups. As for the high refractive index resin 8, the mixture of polyisocyanate and polythiol (having 1.660 refractive index after hardened) can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat plate type microlens used for a liquid crystal display device or the like.

[0002]

2. Description of the Related Art A liquid crystal display device is used in a projector television (PTV). This liquid crystal display element is 2
Liquid crystal is injected into a gap formed between the glass plates, and a TFT (thin film transistor) made of amorphous silicon or polysilicon is formed on a surface of each glass plate in contact with the liquid crystal, corresponding to each pixel. In a PTV using a transmissive liquid crystal display element, irradiation light is applied to the liquid crystal display element from a xenon lamp, a metal halide lamp, or the like, and is transmitted to an emission side through a pixel opening of the liquid crystal display element. The formed image is projected on a screen via a projection lens.

[0003] In order to increase the ratio of the irradiating light transmitted through the liquid crystal display element by condensing the irradiating light to the pixel opening and to make the projected image brighter, two glass substrates constituting the liquid crystal display element are used. Japanese Patent Application Laid-Open No. 3-214101 proposes a technique in which a flat microlens is joined to a glass substrate on the side on which the irradiation light is incident so that the irradiation light is condensed on a pixel opening.

As a method of manufacturing such a flat plate type microlens, a method using an HF (hydrogen fluoride) type etchant is known. In this method, a mask having fine holes formed on a glass substrate is overlapped, and the glass substrate is immersed in an etchant liquid in this state, and isotropically etched with the etchant from the fine holes to form a hemispherical concave portion on the glass substrate. Then, except for the mask, the concave portion is filled with a high refractive index resin.

[0005]

As described above, the flat plate type microlens is often used as a part of the liquid crystal display device or in combination with the liquid crystal display device. Then, the liquid crystal display element has a TFT or the like incorporated therein as a constituent element, and if there is a large difference in thermal expansion as compared with this TFT, the function of the liquid crystal display element itself becomes defective. To show specific numerical values, there are α-SiTFT, low-temperature polySiTFT, and high-temperature polySiTFT as the TFT. However, the glass substrate suitable for α-SiTFT has a thermal expansion coefficient of about 45 × 10 ^-7 / ° C, which is low temperature polySiTFT. The coefficient of thermal expansion of a suitable glass substrate is 3
5 × a 10 ^-7 / ° C. approximately, the thermal expansion coefficient of the glass substrate suitable for high temperature polySiTFT is about 6 × 10 ^-7 / ℃.

As a glass substrate particularly suitable for high temperature polySiTFT, quartz glass (expansion coefficient α = 6 × 10) is generally used.
^-7 / ° C) is used. The numerical aperture (NA) of a microlens using a quartz glass substrate has a refractive index of 1.4 for quartz glass.
6 and the refractive index n of the high refractive index transparent resin material (n-1.
46). The numerical aperture (NA) of the microlens is increased in order to effectively collect the illumination light on the liquid crystal aperture window by using the microlens and increase the amount of transmitted light, thereby improving the brightness of the liquid crystal display element. Is essential.

Further, a relatively inexpensive low-expansion crystallized glass substrate (expansion coefficient α ~
0) has come to be used as a substrate for high temperature polySiTFT. As the low expansion crystallized glass substrate, Neoceram (registered trademark) (66SiO ₂ ) manufactured by Nippon Electric Glass Co., Ltd. is used.
.22Al ₂ O ₃ .4LiO ₂ .2ZrO ₂ .2TiO ₂ ) is known. Although this crystallized glass has a small expansion coefficient, it has a high refractive index (up to 1.54), and therefore has a high N of the microlens.
In order to realize A, a resin having a higher refractive index must be filled.

[0008]

In order to solve the above problems, according to the present invention, a plurality of substrates each of which has a substantially spherical surface or a substantially cylindrical shape is formed on the surface of a substrate made of quartz glass or low expansion crystallized glass. The recesses are arranged one-dimensionally or two-dimensionally, and these recesses are filled with a transparent resin material having a refractive index higher than that of the substrate, or the surface where the recesses are filled with a transparent resin material having a refractive index higher than that of the substrate is covered glass. In the flat plate type microlens in which the concave portion is a convex lens or a lenticular lens, the transparent resin material has a thiol (R—S—H) or a sulfide bond (R—S—R ′). did.

Hydrocarbons constituting the high refractive index resin include phenyl group, alkylene, polymethylene and the like, and high refractive index resin containing isocyanate group, acryloyl group and methacryloyl group is suitable.

Specific examples of the high-refractive-index resin include a mixture of polyisocyanate and polythiol (refractive index after curing = 1.660) and structural formulas shown in the following (Chemical formula 3) to (Chemical formula 10). A polymer having a monomer as a starting material can be used.

[0011]

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[0012]

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[0013]

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[0014]

[Chemical 6]

[0015]

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[0016]

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[0017]

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[0018]

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[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a sectional view of a liquid crystal display device incorporating a flat plate type microlens using a glass substrate according to the present invention, FIG. 2 is a plan view of the flat plate type microlens, and FIG. 3 is a plan view of the flat plate type microlens. FIG. 2A is an enlarged cross-sectional view of a main part, in which FIG. 1A shows a type in which a high refractive index resin is exposed on one surface of a substrate, and FIG. 2B shows a type in which a high refractive index resin is sandwiched between two substrates. .

The liquid crystal display element 1 comprises a pair of glass substrates 2 and 3
The liquid crystal 4 is injected and filled between the glass substrate 2 and the counter electrode 2
The TFT 3a is formed on the surface of the glass substrate 3 on the side in contact with the liquid crystal 4.

Then, a flat plate type microlens 5 is bonded to the glass substrate 2, and the flat plate type microlens 5 is formed on a glass substrate 6 having the composition of the present invention by a wet etching using HF as an etchant to form a hemispherical concave portion 7. Are formed corresponding to the pixels, and the concave portion 7 is filled with the high refractive index resin 8 to form the lens portion. Further, a groove 9 is formed on the outer peripheral portion of the glass substrate 6, and a surplus when the recess 7 is filled with the high-refractive-index resin 8 is received by the groove 9, and the high-refractive-index resin from the outer periphery of the flat plate type microlens 5 is received. 8 is trying not to stick out. Note that the high refractive index resin 8 may be used as an adhesive between the glass substrate 2 and the flat microlens 5.

Incidentally, in the example shown in FIG.
Although the flat plate type microlens 5 is bonded to the above, the liquid crystal may be injected between the flat plate type microlens 5 and the glass substrate 3 without providing the glass substrate 2.

Further, as shown in FIG. 3B, the structure of the flat microlens 5
It is also possible to bond many glass substrates 10 on the surface on which is formed and sandwich the high refractive index resin 8 between these glass substrates 6 and 10 to form a flat plate type microlens having a structure in which the high refractive index resin 8 is not exposed. Is.

[0024]

As described above, according to the flat plate type microlens according to the present invention, since the high refractive index resin having relatively high heat resistance is used, a high numerical aperture (NA) can be realized. it can. As a result, the illumination light is condensed on the opening window of the liquid crystal, the amount of transmitted light is increased, and the brightness of the liquid crystal display element can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a liquid crystal display device incorporating a flat plate type microlens using a glass substrate according to the present invention.

FIG. 2 is a plan view of the flat plate type micro lens.

FIG. 3 is an enlarged sectional view of a main part of the flat plate type micro lens,
Among them, (a) shows a type in which a high refractive index resin is exposed on one surface of a substrate, and (b) shows a type in which a high refractive index resin is sandwiched between two substrates.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element, 2, 3 ... Glass substrate which comprises a liquid crystal display element, 4 ... Liquid crystal, 5 ... Flat micro lens, 6,
Reference numeral 10: a glass substrate constituting a flat microlens;
... recess, 8 ... high refractive index resin.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08F 22/24 MMV C08F 22/24 MMV 28/04 MNR 28/04 MNR (72) Inventor Kenji Morio 3-5-11 Doshu-machi, Chuo-ku, Osaka-shi, Osaka Prefecture Nippon Sheet Glass Co., Ltd. (72) Inventor Daisuke Arai 3-5-11, Dosho-machi, Chuo-ku, Osaka City, Osaka Prefecture (72) Inventor, Nippon Sheet Glass (72) Takashi Kishimoto 3-5-11 Doshumachi, Chuo-ku, Osaka-shi, Osaka Prefecture Nippon Sheet Glass Co., Ltd. (72) Inventor Kenichi 3-5-11, Dosho-machi, Chuo-ku, Osaka City, Osaka Prefecture Nippon Sheet Glass Co., Ltd.

Claims (6)

[Claims] 1. A plurality of recesses each having a shape of a part of a substantially spherical surface or a part of a substantially columnar shape are arranged in a one-dimensional or two-dimensional shape on a surface of a substrate made of quartz glass or low-expansion crystallized glass. A transparent resin material having a refractive index higher than that of the substrate, or by providing a cover glass on the surface of the recess filled with a transparent resin material having a refractive index higher than that of the substrate, a concave lens is formed as a convex lens or a lenticular lens. The flat plate type microlens, wherein the transparent resin material has a thiol (R—S—H) or a sulfide bond (R—S—R ′). However, R and R'are hydrocarbon groups, S is sulfur, and H is hydrogen. 2. The flat plate microlens according to claim 1, wherein the hydrocarbon group (R, R ′) is a phenyl group (—C ₆ H ₅ ). 3. The flat plate type microlens according to claim 1, wherein the hydrocarbon group (R, R ′) is (—CH _{2
CH 2 -), (- CH} 3 CHCH 2 -), (- CH 2 CH 2
CH ₂ -) plate type microlens, which is a alkylene or polystyrene whose general formula is expressed as (-C _n H _2n), such as. 4. The flat plate microlens according to claim 1, wherein the transparent resin material contains an isocyanate group (—N═C═O). 5. The flat plate type microlens according to claim 1, wherein the transparent resin material contains an aliphatic unsaturated acyl group such as an acryloyl group or a methacryloyl group represented by the following (Chemical Formula 1). A flat plate type microlens characterized by that. Embedded image 6. The flat plate type microlens according to claim 1, wherein the transparent resin material contains an epoxy group represented by the following (Chemical Formula 2). Embedded image