JP2001277260A - Micro-lens array, its production method, and original board and display for producing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a micro-lens array, a method for producing the array stably in a good yield, and an original board and a display for the production of the array. SOLUTION: A process (B) in which a substrate is adhered to the original board having at least one lens array forming area and a flat area formed on the periphery of the lens array forming area on one surface through a light transmittable layer precursor, and the lens array forming area is transferred/ formed to/in the precursor and a process (C) in which the precursor is cured are included, and grooves or recessed parts are formed on a surface facing the flat area of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a microlens array, a method for manufacturing the same, a master for manufacturing the same, and a display device.

[0002]

2. Description of the Related Art As a method of manufacturing a microlens array used for a liquid crystal display panel or the like, Japanese Patent Application Laid-Open No. HEI 3-19800 is disclosed.
The method disclosed in Japanese Patent Application Laid-open No. 3 and Japanese Patent Application Laid-Open No. 5-303,093 is known. According to these, the resin was dropped on a master on which a number of concave portions corresponding to a number of convex lenses were formed, the resin was cured to form a light-transmitting layer, and the master was peeled off, whereby the concave portions were transferred. A microlens array having convex lenses can be manufactured. Japanese Patent Laid-Open No. 5-303,093 discloses that a metal plate is etched to form a master.

[0003]

SUMMARY OF THE INVENTION In the conventional manufacturing method,
After laminating the master and the substrate, the resin protrudes from the edges, causing defects and reducing the yield, or
There is a problem in that post-processing such as removal of the protruding resin is troublesome. An object of the present invention is to solve such a problem, and an object of the present invention is to provide a microlens array that is stable and has a high yield, a method of manufacturing the same, a master for manufacturing the same, and a display device.

[0004]

(1) In a method of manufacturing a microlens array according to the present invention, at least one lens array forming region and a flat region formed around the lens array forming region are formed in one. A step of bringing a substrate into close contact with a master having two surfaces via a light-transmitting layer precursor, transferring and forming the lens array formation region to the light-transmitting layer precursor, and curing the light-transmitting layer precursor A groove or a concave portion is formed in a surface of the substrate facing the flat region.

(2) In the microlens array manufacturing method of (1), the groove or the concave portion may be formed between an end of the substrate and the lens array forming region.

(3) (1) In the method of manufacturing a microlens array, the groove or the concave portion can be formed by machining.

(4) In the method of manufacturing a microlens array of (1), the groove or the concave portion may be formed by dry etching or wet etching.

(5) In the method of manufacturing a microlens array of (1), the groove or the concave portion may be formed by FIB (focused ion beam) processing or laser processing.

(6) The microlens array manufacturing master of the present invention comprises at least one lens array forming region,
And a flat region formed around the lens array forming region on one surface, and a convex portion is formed in the flat region.

(7) In the master for manufacturing a microlens array according to (6), the convex portion may be formed between an end of the master and the lens array forming region.

(8) A method of manufacturing a microlens array according to the present invention, wherein the master having at least one lens array forming region and a flat region formed around the lens array forming region on one surface. A step of bringing the substrate into close contact with the light-transmitting layer precursor through the light-transmitting layer precursor, transferring the lens array formation region to the light-transmitting layer precursor, and curing the light-transmitting layer precursor. The method is characterized in that a convex portion is formed in the flat region.

(9) In the method of manufacturing a microlens array according to (8), the projection may be formed between an end of the master and the lens array formation region.

(10) The microlens array according to the present invention is manufactured by any one of the above methods (1) to (5), (8) and (9).

(11) A display device according to the present invention includes the microlens array according to (10).

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

(Master for Manufacturing Microlens Array) FIG. 1
1 is a plan view of a master used in the present embodiment. The master 10 can be formed from a disk-shaped or rectangular base material. The master 10 forms at least one (in many cases, a plurality of) microlens arrays at a time. On one surface of the master 10, at least one (in many cases, a plurality of) lens array forming regions 12 corresponding to individual microlens arrays are formed. A flat region 18 is formed around each lens array formation region 12. The flat region 18 includes a plurality of lens array formation regions 12.
Are formed at intervals, the area between adjacent lens array forming areas 12 is also included. A plurality of concave portions 16 are formed in each lens array forming region 12. For example, a plurality of recesses 16 are formed in a matrix in a plurality of rows and a plurality of columns. The concave portion 16 has a shape corresponding to each convex lens of the microlens array.

(Manufacturing Method of Master) FIG. 2 is a diagram showing a manufacturing process of the master used in the present embodiment. First, FIG.
As shown in (A), a resist layer 22 is formed on a substrate 20. The base material 20 is processed into the master 10. The concave portion 16 is formed by etching the substrate 20.
Therefore, the substrate 20 is not particularly limited as long as it is a material that can be etched, but silicon or quartz is
It is preferable because the recess 16 can be formed with high precision by etching. As the material for forming the resist layer 22, for example, a commercially available positive resist generally used in the manufacture of semiconductor devices, which is prepared by blending a diazonaphthoquinone derivative as a photosensitive agent with a cresol novolak resin, can be used as it is. Here, the positive resist is a substance that can be selectively removed by a developer when exposed to radiation according to a predetermined pattern. As a method of forming the resist layer 22, it is possible to use a method such as a spin coating method, a dipping method, a spray coating method, a roll coating method, and a bar coating method. next,
As shown in FIG. 2B, the mask 24 is
And only a predetermined area of the resist layer 22 is exposed by the radiation 26 via the mask 24. Mask 2
Reference numeral 4 denotes a pattern formed so that the radiation 26 is transmitted only in a region required for forming the concave portion 16 shown in FIG. The radiation 26 has a wavelength of 200 nm.
It is preferable to use light in the region of -500 nm. The use of light in this wavelength region makes it possible to use the photolithography technology established in the liquid crystal panel manufacturing process and the like and the equipment used therefor, and to reduce costs. Then, the resist layer 22 is irradiated with radiation 26.
After the development process is performed under predetermined conditions after the exposure, the exposed region 2 of the radiation 26 is exposed as shown in FIG.
Only in 8, a part of the resist layer 22 is selectively removed to expose the surface of the base material 20, and other areas remain covered by the resist layer 22. When the resist layer 22 is patterned in this manner, as shown in FIG.
Is etched to a predetermined depth. More specifically, isotropic etching is performed on a region of the base material 20 exposed from the resist layer 22 so that the etching proceeds in any direction. For example, isotropic etching can be performed by immersing the base material 20 in a chemical solution (etching solution) by applying wet etching. When quartz is used as the base material 20, etching is performed using, for example, an aqueous solution (buffered hydrofluoric acid) in which hydrofluoric acid and ammonium fluoride are mixed as an etchant. The recess 16 is formed in the base material 20 by performing the isotropic etching. Next, after the completion of the etching, the resist layer 22 is removed as shown in FIG. In the present embodiment, the master 10 is economical since once manufactured, it can be used as many times as the durability permits. In addition, the manufacturing process of the master 10 can be omitted in the manufacturing process of the second and subsequent microlens arrays, so that the number of processes and the cost can be reduced. In the above process, when forming the concave portion 16 in the base material 20, a positive resist was used. However, the area exposed to the radiation became insoluble in the developer, and the area not exposed to the radiation was exposed to the developer. A negative resist that can be selectively removed may be used. In this case, a mask whose pattern is inverted from that of the mask 24 is used. Alternatively, the resist may be directly exposed in a pattern by using a laser beam or an electron beam without using a mask. Further, instead of the resist, a metal such as gold or chromium, or Si or SiO ₂ may be used.

(Method of Manufacturing Microlens Array) FIG. 3
FIG. 3 is a diagram showing a method for manufacturing a microlens array according to an embodiment to which the present invention is applied.

As shown in FIG. 3A, the light transmitting layer precursor 32 is transferred to the concave portion 16 and the flat region 18 of the master 10.
Place on the surface on which is formed. As shown in FIG. 3B, the substrate 34 and the master 10 are brought into close contact with each other via the light-transmitting layer precursor 32, so that the light-transmitting layer precursor 32 is spread to a predetermined region. As shown in FIG.
A layer made of the light transmitting layer precursor 32 is formed between the substrate and the substrate. This layer becomes the light transmissive layer 40 when solidified. FIG. 4A is a plan view of the substrate 34 used in this embodiment, and FIG. 4B is a plan view of the substrate 34 shown in FIG.
It is a line sectional view. A groove or recess 14 is provided in advance on a surface of the master 10 facing the flat region 18. The groove or recess 16 may be any surface as long as it faces the flat region 18, but is preferably between the end of the substrate 34 and the lens array formation region 12 as shown in FIG. By doing this,
When spreading the light transmitting layer precursor 32 in the steps of FIGS. 3B to 3C, the light transmitting layer precursor 3
2 can be prevented from protruding. If the light-transmitting layer precursor 32 protrudes, a removal step is required, and it also causes contamination and lowers the yield. As a method for forming the groove or the concave portion 14, machining may be used. Further, dry etching or wet etching may be used. Alternatively, it may be formed directly by FIB (focused ion beam) processing or laser processing. The shape of the groove or the concave portion 16 is shown in FIGS.
The light-transmitting layer precursor 32 can be prevented from protruding. Since the dimensional accuracy of the groove or recess 16 is not so required, it can be provided by simple means. Here, the light-transmitting layer precursor 32
Was placed on the master 10, but was placed on the substrate 34 or the master 1
0 and the substrate 34. Master 10
The light-transmitting layer precursor 32 may be applied to a predetermined region on one or both of the substrate 34 and the substrate 34 in advance. If necessary, when the master 10 and the substrate 34 are brought into close contact with each other via the light-transmitting layer precursor 32, the light-transmitting layer precursor 32 is connected via at least one of the master 10 and the substrate 34. Pressure may be applied. By applying pressure, the time required for the light transmissive layer precursor 32 to spread to a predetermined area can be shortened, so that workability is improved, and the light transmissive layer precursor 32 is reliably filled in the recesses 16. Here, the light-transmitting layer precursor 32 is preferably a liquid or a liquefiable substance. By using the liquid state, it becomes easy to fill the plurality of recesses 16 on the master 10 with the light transmitting layer precursor 32. As the liquid substance, a substance that can be cured by applying energy can be used, and as the liquefiable substance, a plastic substance can be used. The light-transmitting layer precursor 32 is not particularly limited as long as it has required characteristics such as light transmission when the light-transmitting layer 40 is formed. Is preferred. As the resin, a resin having energy curability or a resin having plasticity is easily obtained, and is preferable.
It is desirable that the resin having energy curability be curable by application of at least one of light and heat. For the use of light and heat, a general-purpose exposure apparatus, a heating apparatus such as a baking furnace or a hot plate can be used, and the equipment cost can be reduced. Examples of such an energy-curable resin include an acrylic resin, an epoxy resin, a melamine resin, and a polyimide resin. In particular, an acrylic resin is preferable because it can easily be cured by irradiation with light by using various commercially available precursors and photosensitive agents (photopolymerization initiators). Specific examples of the basic composition of the photocurable acrylic resin include a prepolymer or oligomer, a monomer, and a photopolymerization initiator. As the prepolymer or oligomer, for example, acrylates such as epoxy acrylates, urethane acrylates, polyester acrylates, polyether acrylates, spiroacetal acrylates, epoxy methacrylates, urethane methacrylates,
Methacrylates such as polyester methacrylates and polyether methacrylates can be used. As the monomer, for example, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone, carbitol acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, Monofunctional monomers such as dicyclopentenyl acrylate and 1,3-butanediol acrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, ethylene Bifunctional monomers such as glycol diacrylate, polyethylene glycol diacrylate, and pentaerythritol diacrylate, trimethylol Propane triacrylate, trimethylol propane trimethacrylate, Pentaerisuri tall triacrylate, polyfunctional monomers such as dipentaerythritol hexaacrylate available. As the photopolymerization initiator, for example, 2,2-dimethoxy-2
Acetophenones such as phenylacetophenone, α-
Hydroxyisobutylphenone, p-isopropyl-α
Butylphenones such as -hydroxyisobutylphenone, p-tert-butyldichloroacetophenone, p
-Tert-butyltrichloroacetophenone, α, α
-Halogenated acetophenones such as -dichloro-4-phenoxyacetophenone, benzophenones such as benzophenone, N, N-tetraethyl-4,4-diaminobenzophenone, benzyls such as benzyl and benzyldimethylketal, benzoin, benzoin alkyl ether and the like. Benzoins, oximes such as 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, xanthones such as 2-methylthioxanthone and 2-chlorothioxanthone, radicals such as Michler's ketone and benzylmethylketal Generated compounds are available. If necessary, a compound such as an amine may be added to prevent curing inhibition by oxygen, or a solvent component may be added to facilitate coating. The solvent component is not particularly limited, and various organic solvents,
For example, propylene glycol monomethyl ether acetate, methoxymethyl propionate, ethoxyethyl propionate, ethyl lactate, ethyl pyrpinate, methyl amyl ketone and the like can be used. These materials are preferable because they have good releasability from silicon or quartz, which is excellent as a material of the master 10 in that high-precision etching is possible. As the resin having plasticity, for example, a resin having thermoplasticity such as a polycarbonate resin, a polymethyl methacrylate resin, and an amorphous polyolefin resin can be used.
Such a resin is plasticized by heating to a temperature equal to or higher than the softening point to be in a liquid state, and is sandwiched between the master 10 and the substrate 34 to form a layer, as shown in FIG. By bringing the master 10 and the substrate 34 into close contact with each other via the light-transmitting layer precursor 32, the light-transmitting layer precursor 32 has a shape corresponding to the concave portion 16 of the master 10. That is, the concave portions 16 can be transferred to the light transmitting layer precursor 32 to form the convex portions 38. Then, a solidification process corresponding to the light-transmitting layer precursor 32 is performed. For example, when a photo-curable resin is used, light is irradiated under predetermined conditions. Thereby, the light transmitting layer precursor 32 is solidified, and the light transmitting layer 40 can be formed as shown in FIG. When forming the light-transmitting layer 40 with a photocurable substance, the substrate 3
At least one of the master 4 and the master 10 needs to have optical transparency. Alternatively, when a plasticized resin heated to a temperature equal to or higher than the softening point is used as the light-transmitting layer precursor 32, it can be solidified by cooling. As described above, by forming the light transmitting layer precursor 32 from a substance curable by application of energy or a substance having plasticity, when the precursor 32 is applied to and closely adhered to the master 10, it is formed on the master 10. The light transmitting layer precursor 32 is filled up to the minute portion of the recess 16 that has been formed. Then, when the light transmitting layer 40 is formed by being solidified by performing a solidification treatment corresponding to the light transmitting layer precursor 32,
The concave portion 16 of the master 10 can be precisely transferred to the light transmitting layer 40. The substrate 34 is not particularly limited as long as it satisfies optical properties such as light transmittance required for a microlens array and characteristics such as mechanical strength. It is possible to use a substrate or a film made of glass or a plastic such as polycarbonate, polyarylate, polyethersulfone, polyethylene terephthalate, polymethyl methacrylate, and amorphous polyolefin. Next, as shown in FIG.
The light transmissive layer 40 and the substrate 34 are peeled off. If the light-transmitting layer 40 alone can satisfy the characteristics such as mechanical strength required for the microlens array, the substrate 34 is unnecessary. You may peel off. This peeling step may be before or after peeling the light-transmitting layer 40 from the master 10. The light transmissive layer 40 has a plurality of convex portions 38 corresponding to the concave portions 16 of the master 10, so that it becomes a microlens array having convex lenses. If the master 10 manufactures a plurality of products, the light transmitting layer 40
Since a plurality of microlens arrays are integrated, individual products can be obtained by cutting the microlens arrays into individual pieces. Next, FIG. 5 is a diagram showing a modification of the master according to the embodiment to which the present invention is applied. In FIG.
Has a convex portion 15 formed in a flat region 18 formed around the lens array forming region 12. By doing so, the light-transmitting layer precursor 3 in the steps of FIGS.
When spreading 2, the light-transmitting layer precursor 32 can be prevented from protruding from the edge of the substrate 34. If the light-transmitting layer precursor 32 protrudes, a removal step is required, and it also causes contamination and lowers the yield. The convex portion 15 may be located anywhere within the flat region 18, but is preferably located between the end of the master 10 and the lens array forming region 12. Since the dimensional accuracy of the protrusion 15 is not so required, it may be provided in advance by machining or etching. Further, it may be directly bonded to the master 10 or bonded with an adhesive. FIG. 6 is a diagram illustrating a part of a liquid crystal projector as an example of a display device to which the microlens array according to the present invention is applied. This liquid crystal projector has a light valve 80 incorporating a microlens array manufactured by the method according to the above-described embodiment.
And a lamp 90 as a light source. The microlens array includes a light transmitting layer 4 on which a plurality of convex portions 38 are formed.
0. The convex portion 38 is a convex lens. The microlens array includes a convex lens and a lamp 90.
It is arranged so as to be concave when viewed. The light transmitting layer 81 is provided on the surface of the microlens array where the convex portions are formed.
Are formed. Light is refracted by the interface between the microlens array and the light transmitting layer 81. On the light transmitting layer 81, a black matrix 82, an electrode film 83, and an alignment film 84 are formed. A TFT substrate 85 is provided with a gap from the alignment film 84. TFT substrate 85
Are provided with transparent individual electrodes 86 and thin film transistors 87, on which an alignment film 88 is formed. Further, the TFT substrate 85 is formed by aligning the alignment film 88 with the alignment film 8
4 and are disposed opposite to each other. A liquid crystal 89 is sealed between the alignment films 84 and 88, and a thin film transistor 87 is formed.
The liquid crystal 89 is driven by the voltage controlled by. According to this liquid crystal projector,
Since the light 92 emitted from the lamp 90 is condensed by the lens constituted by the convex portion 38 for each pixel, a bright screen can be displayed. It is assumed that the light refractive index na of the light transmitting layer 81 and the light refractive index nb of the light transmitting layer 40 forming the microlens array are na <na.
nb. By satisfying this condition, light is incident from a medium having a large refractive index to a medium having a small refractive index, and the light 92 is refracted away from the normal to the interface between the two media, that is, is refracted at an angle and condensed. I do.
Then, the screen can be brightened.

[Brief description of the drawings]

FIG. 1 is a diagram showing a master used for manufacturing a microlens array according to an embodiment to which the present invention is applied.

FIGS. 2A to 2E are cross-sectional views showing a method of manufacturing a microlens array manufacturing master according to an embodiment to which the present invention is applied, along the steps.

FIGS. 3A to 3C are cross-sectional views illustrating a method of manufacturing a microlens array according to an embodiment to which the present invention is applied, along the steps.

FIG. 4 is a diagram illustrating an example of a substrate according to an embodiment to which the present invention is applied;

FIG. 5 is a diagram showing another example of the master according to the embodiment to which the present invention is applied;

FIG. 6 is a diagram showing a display device incorporating a microlens array according to an embodiment to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Master disk 12 Lens array formation area 14 Groove or concave part 15 Convex part 16 Concave part 18 Flat area 32 Light transmissive layer precursor 40 Light transmissive layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 11:00 G02F 1/1335 530 F-term (Reference) 2H091 FA29X FB04 FC26 GA01 LA30 2H096 AA28 HA11 HA17 HA23 JA04 4F202 AA21 AA44 AH75 CA01 CB01 CD18 CD24 CK85 4F204 AA21 AA44 AH75 EA03 EB01 EK18

Claims (11)

[Claims] A substrate is brought into close contact with a master having at least one lens array formation region and a flat region formed around the lens array formation region on one surface via a light transmitting layer precursor. Transferring the lens array formation region to the light transmitting layer precursor, and curing the light transmitting layer precursor, including a groove or a groove on the surface of the substrate facing the flat region. A method for manufacturing a microlens array in which concave portions are formed. 2. The method of manufacturing a microlens array according to claim 1, wherein said groove or recess is formed between an end of said substrate and said lens array formation region. 3. The method of manufacturing a microlens array according to claim 1, wherein said groove or recess is formed by machining. 4. The method of manufacturing a microlens array according to claim 1, wherein said grooves or recesses are formed by dry etching or wet etching. 5. The method of manufacturing a microlens array according to claim 1, wherein the groove or the concave portion is formed by FIB processing or laser processing. 6. A micro-device having at least one lens array formation region and a flat region formed around the lens array formation region on one surface, wherein a convex portion is formed in the flat region. Master for manufacturing lens arrays. 7. A master for manufacturing a microlens array according to claim 6, wherein said convex portion is formed between an end of said master and said lens array forming region. 8. A substrate is brought into close contact with a master having at least one lens array forming region and a flat region formed around the lens array forming region on one surface via a light transmitting layer precursor. Transferring the lens array forming region to the light transmitting layer precursor, and curing the light transmitting layer precursor, and forming a convex portion in the flat region. A method for manufacturing a lens array. 9. The method of manufacturing a microlens array according to claim 8, wherein said convex portion is formed between an end of said master and said lens array forming region. 10. A microlens array manufactured by the method according to claim 1. 11. A display device having the microlens array according to claim 10.