JP4277536B2 - Optical component, method for manufacturing the same, and image projection screen - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical article having a screen or an optical element for a projection television for projecting an image from an optical engine having a cell structure such as an LCD (Liquid Crystal Display) or DMD (Digital-Micromirror-Device).
[0002]
[Prior art]
An example of an optically useful fine concavo-convex pattern is a Fresnel lens. As a manufacturing method of the Fresnel lens, there are a hot press molding method, a casting method, an injection method, and the like. However, when these methods are used, when molding a large product, it takes a long time for heating and cooling, and productivity cannot be increased. Therefore, recently, a photopolymer method (2P method) in which an ultraviolet curable resin is interposed between the lens mold and the transparent resin base material and is cured in a short time by irradiating ultraviolet rays has a short manufacturing cycle and shape transferability. From the point, it has become mainstream (for example, refer to Patent Document 1).
[0003]
On the other hand, with the recent improvement in projector brightness, it is possible to distribute the extra front brightness to the horizontal or vertical viewing angle in order to make effective use of its performance. Improvement is becoming desired. For this reason, having an optically useful fine pattern (for example, Fresnel lens) only on one side is insufficient as a function, and a fine uneven pattern (for example, lenticular lens) having the function of expanding the vertical viewing angle is extruded. There has been proposed a method of forming a Fresnel lens by the 2P method using the substrate formed by the above (see Patent Document 2, for example).
[0004]
According to this method, when forming a lenticular lens or prism lens shape different from the Fresnel lens shape, it is performed by extrusion molding. Therefore, in the case of a large lot, a continuous shape such as a lenticular lens or prism lens shape is used. In addition, since a regular pattern can be completely formed, there is an advantage that productivity is good.
[0005]
However, in the case of a Fresnel lens for projection television, it is often a small lot and a wide variety, and if the shape of the lenticular lens or prism lens is formed by extrusion as described above, the productivity is lowered. The reason why productivity is lowered is that it is necessary to exchange rolls depending on the type (especially pitch) in an extruder, and the exchange is complicated. Further, when molding a small lot and a variety of products with an extruder, the resin pellets are likely to be wasted every time the roll is changed. In addition to the decrease in productivity, when a thermoplastic resin such as extrusion molding is used, due to the thermal process, the heat return phenomenon unique to the thermoplastic resin when molding the shape of a lenticular lens or prism lens causes a minute Producing a high-quality screen with a wide viewing angle in the vertical direction of the observation screen because it is difficult to transfer the pitch (specifically 0.3 mm or less) in a deep shape and it is difficult to transfer it sufficiently (insufficient transfer) There are aspects that are difficult to say.
[0006]
[Patent Document 1]
JP-A-61-177215 [Patent Document 2]
Japanese Patent Laid-Open No. 5-177215
[Problems to be solved by the invention]
The present invention has been devised in view of the above-mentioned problems, and is intended to solve the inconvenience when molding small lots of various products by extrusion molding, waste of resin, and inaccurate fine pitch reproducibility due to thermal processes. Therefore, an object of the present invention is to provide an optical article having an optical element such as a fine lenticular lens or a Fresnel lens having a prism lens shape with high quality and at low cost.
[0008]
[Means for Solving the Problems]
In order to achieve the above object in the present invention, first, in claim 1, in an optical article having an optically useful fine concavo-convex pattern formed on a translucent substrate, both surfaces of the translucent substrate are provided. The optical article is characterized in that a fine concavo-convex pattern is formed of an ultraviolet curable resin, and the ultraviolet curable resin is different on both sides.
[0009]
According to a second aspect of the present invention, in the optical article according to the first aspect, the fine concavo-convex pattern is formed of any one of a lenticular lens, a prism lens, a Fresnel lens, and a microlens array group. is there.
[0010]
According to a third aspect of the present invention, at least the following steps are provided. The method for manufacturing an optical component according to the first or second aspect is provided.
(A) The process of preparing the translucent base material and the shaping | molding die in which the inversion type | mold of the 1st fine uneven | corrugated pattern was formed.
(B) A first ultraviolet curable resin solution is filled between the translucent substrate and the mold, and the entire surface is exposed to ultraviolet rays from the translucent substrate side. The process of hardening.
(C) A step of releasing the mold on which the inverted mold of the first fine concavo-convex pattern is formed, and forming the first fine concavo-convex pattern on one surface on the translucent substrate.
(D) The process of preparing the translucent base material in which the 1st fine uneven | corrugated pattern was formed in one surface, and the shaping | molding die in which the 2nd fine uneven | corrugated pattern was formed.
(E) a second ultraviolet curable resin solution between a translucent substrate having a first fine concavo-convex pattern formed on one surface and a mold having an inverted mold of the second fine concavo-convex pattern formed thereon Satisfying the above, exposing the entire surface from the translucent substrate side, and curing the second ultraviolet curable resin solution.
(F) The mold on which the inverted mold of the second fine concavo-convex pattern is formed is released, and the first fine concavo-convex pattern is formed on one surface of the translucent substrate, and the first fine concavo-convex pattern is formed on the other surface. The process of producing the optical component in which the uneven | corrugated pattern was formed.
[0011]
According to a fourth aspect of the present invention, there is provided an image projection screen characterized by using the optical article according to the first or second aspect.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1 to 3, in the optical component of the present invention, the first fine concavo-convex pattern (31 a, 31 b and 31 c) and the second fine concavo-convex pattern (32 a) are formed on both surfaces of the translucent substrate 11. The first fine concavo-convex pattern (31a, 31b and 31c) and the second fine concavo-convex pattern (32a) are formed from different ultraviolet curable resins. The first fine concavo-convex pattern (31a, 31b, and 31c) and the second fine concavo-convex pattern (32a) are configured by any of a lenticular lens, a prism lens, a Fresnel lens, or a microlens array group. The component 10 is an example in which the first fine concavo-convex pattern 31a is a combination of a lenticular lens and the second fine concavo-convex pattern 32a is a Fresnel lens. The optical component 20 in FIG. 3 and the second fine concavo-convex pattern 32a in combination with a Fresnel lens. In the optical component 30 of FIG. 3, the first fine concavo-convex pattern 31c is a microlens array and the second fine concavo-convex pattern 32a is a Fresnel lens. This is an example of combination.
The reason why the ultraviolet curable resin in which the first fine uneven pattern and the second fine uneven pattern are different will be described later.
[0013]
The optical component of the present invention is produced by a 2P method using a mold having an inverted mold of the first and second fine concavo-convex patterns and an ultraviolet curable resin solution.
4A to 4F show an example of the manufacturing process of the optical component of the present invention.
Hereinafter, a method for manufacturing an optical component of the present invention using a lenticular lens as the first fine concavo-convex pattern 31a and a Fresnel lens as the second fine concavo-convex pattern 32a will be described.
First, a translucent substrate 11 and a mold 21 on which an inversion mold of the first fine uneven pattern 31a is formed are prepared (see FIG. 4A).
Here, as the translucent substrate 11, for example, an acrylic resin, an MS resin, a polycarbonate resin, a polyester resin, a polystyrene resin, a polyolefin resin, a vinyl chloride resin, a polyimide resin, or a sheet and film or glass made of a blend of the above resins. A board etc. can be used. From the viewpoint of releasability from the mold 21, a flexible acrylic resin, polycarbonate resin, polyester resin, MS resin and the like are preferable from the viewpoint of light transmittance and flexibility.
The molding die 21 is made of a processed base material such as copper or brass by a fo-etching method, mechanical processing, laser processing or the like.
[0014]
Next, the first ultraviolet curable resin solution 31 is filled between the translucent substrate 11 and the mold 21, and the entire surface of the translucent substrate 11 is exposed to ultraviolet rays with a UV lamp, whereby the first ultraviolet rays are exposed. The curable resin solution 31 is cured and molding is performed (see FIG. 4B).
As the first ultraviolet curable resin solution 31, in addition to urethane (meth) acrylate and / or epokin (meth) acrylate oligomer to be a base resin, a reaction diluent is added for the purpose of improving the physical properties of the base resin, Furthermore, the composition containing the photoinitiator component so that it may harden | cure with an ultraviolet-ray is mentioned.
Moreover, in order for the 1st ultraviolet curable resin solution 31 to harden | cure, it is necessary for the radiation wavelength range from an ultraviolet lamp and the functional wavelength range of a photoinitiator to be near.
[0015]
Next, the mold 21 is released to form a first fine concavo-convex pattern 31a (lenticular lens) on one surface of the translucent substrate 11 (see FIG. 4C).
[0016]
Next, the translucent base material 11 on which the first fine concavo-convex pattern 31a (lenticular lens) is formed on one surface and the mold 22 on which the reversal mold of the second fine concavo-convex pattern 32a is formed are prepared. (Refer FIG.4 (d)).
[0017]
Next, a second ultraviolet curable resin solution is formed between the translucent base material 11 on which the first fine concavo-convex pattern 31a is formed and the mold 22 on which the reversal mold of the second fine concavo-convex pattern 32a is formed. 32, and the entire surface of the first fine concavo-convex pattern 31a is exposed to ultraviolet rays with a UV lamp to cure the second ultraviolet curable resin solution 32 and perform molding (see FIG. 4E).
[0018]
Next, the mold 22 is released, and the first fine concavo-convex pattern 31a (lenticular lens) is formed on one surface of the translucent substrate 11, and the second fine concavo-convex pattern 32a (Fresnel lens) is formed on the other surface. ) Is obtained (see FIG. 4F).
[0019]
When selecting the first ultraviolet curable resin solution and the second ultraviolet curable resin solution used in manufacturing the optical article, it is necessary to make the functional wavelength ranges different from each other. That is, in the step of curing the second ultraviolet curable resin solution with ultraviolet rays, ultraviolet light is irradiated from the first fine concavo-convex pattern side, so that the functional wavelength range of the second ultraviolet curable resin solution is the first ultraviolet curable type. The wavelength is longer than the functional wavelength range of the resin solution.
[0020]
Specifically, the first fine concavo-convex pattern surface and the second fine concavo-convex pattern surface formed on both surfaces of the translucent substrate 11 such as durability, strength, and hardness are controlled by the base resin. If it is desired to make the difference between the first ultraviolet curable resin and the second ultraviolet curable resin different, the functional wavelength of the second ultraviolet curable resin is set to the first ultraviolet curable resin. The one that is longer than the functional wavelength of the mold resin is selected.
[0021]
On the other hand, the physical properties governed by the base resin, such as durability, strength, and hardness, are the same on the first fine concavo-convex pattern surface formed on both surfaces of the translucent substrate 11 and the second fine concavo-convex pattern surface. In order to achieve this, only the photopolymerization initiator in the ultraviolet curable resin solution is different from the front and back, and the functional wavelength of the photopolymerization initiator contained in the second ultraviolet curable resin solution is changed to the first ultraviolet light. A material that is longer than the functional wavelength of the photopolymerization initiator contained in the curable resin solution is selected.
[0022]
Further, when the first ultraviolet curable resin solution and the second ultraviolet curable resin solution are made the same composition, a photopolymerization initiator having a functional wavelength region on the long wavelength side and a functional wavelength region on the short wavelength side. By using a mixture of a plurality of types of photopolymerization initiators, both photopolymerization initiators react at the time of curing the first UV curable resin solution, and long at the time of curing the second UV curable resin solution. Both sides can be efficiently cured by the reaction of the photopolymerization initiator having a functional wavelength region on the wavelength side. Further, this case is preferable because there is an advantage that the UV resin can be shared.
[0023]
On the other hand, the UV resin itself has a light absorbing action and absorbs ultraviolet rays in a short wavelength region, so that the ultraviolet curable resin layer used for the first fine uneven pattern on the translucent substrate 11 is thick. When an ultraviolet curable resin that absorbs light in the functional wavelength range is used, curing of the ultraviolet curable resin solution used for the second fine concavo-convex pattern surface is insufficient.
[0024]
That is, if the same UV curable resin on both surfaces of the translucent substrate 11 is used, the ultraviolet curable resin itself absorbs ultraviolet rays, and the ultraviolet curable resin layer having the second fine uneven pattern is cured. Is insufficient or the curing speed is significantly reduced.
[0025]
The difference in the light absorption action of the ultraviolet curable resin itself as described above varies depending on the type of the base resin and the type of the photopolymerization initiator. Therefore, by appropriately selecting these, the light absorption region can be selected to some extent, and the curing rate It is possible to prevent a decrease in the above.
[0026]
About the manufacturing method of the optical components 20 and 30, since it is produced in the almost same process as the optical component 10, it abbreviate | omits here.
[0027]
In the method for producing an optical component of the present invention, an ultraviolet curable resin solution is UV cured and molded to form a fine uneven pattern such as a Fresnel lens or a lenticular lens. Therefore, the fine uneven pattern can be transferred with good reproducibility, and It has the merit that it can be manufactured with high productivity even in small lots and many varieties.
[0028]
In addition, by controlling the light absorption region, shifting the light absorption region between the ultraviolet curable resin solution on the first fine concavo-convex pattern surface and the ultraviolet curable resin solution on the second pattern surface, and changing the order of pattern formation The pattern can be formed efficiently. Furthermore, since the pattern is formed by the 2P method using an ultraviolet curable resin on both sides, the fine concavo-convex pattern can be accurately transferred.
[0029]
5 to 7 show examples of an image projection screen using the optical article of the present invention.
The image projection screen 100 of FIG. 5 is an example in which the optical component 10 of the present invention in which a lenticular lens and a Fresnel lens are formed on both surfaces of a translucent substrate 11 and a lenticular screen are combined, and light rays diffuse in the vertical direction. By having a lenticular lens having such an action on the light source side, the viewing angle in the vertical direction on the observation surface is enlarged.
[0030]
The image projection screen 200 in FIG. 6 is an example in which the optical component 20 of the present invention in which a prism lens and a Fresnel lens are formed on both surfaces of a translucent substrate 11 and a lenticular screen, and the light beam is diffused in the vertical direction. By having a prism lens having an appropriate function on the light source side, the viewing angle in the vertical direction is enlarged on the observation surface.
[0031]
The image projection screen 300 of FIG. 7 is an example in which the optical component 30 of the present invention in which a microlens array and a Fresnel lens are formed on both surfaces of a translucent substrate 11 and a lenticular screen are combined. By using a microlens shape, it has an effect of diffusing light rays not only in the vertical direction but also in the horizontal direction, and an image projection screen that is bright at every corner on the observation surface.
[0032]
【The invention's effect】
Since the optical component of the present invention is produced by ultraviolet curing and mold-molding an ultraviolet curable resin solution, a fine uneven pattern such as a Fresnel lens or a lenticular lens can be reproduced with high accuracy.
Further, in the method of manufacturing an optical component according to the present invention, the light absorption region is controlled, and the light absorption region between the ultraviolet curable resin solution on the first fine uneven pattern surface and the ultraviolet curable resin solution on the second pattern surface is formed. By shifting and changing the order of pattern formation, it is possible to efficiently form a fine uneven pattern, and it is possible to easily cope with the production of many kinds of small lots, and there is little waste of materials during production.
Furthermore, the image projection screen using the optical component of the present invention is bright on every corner on the observation surface, and can enlarge the viewing angle in the vertical direction.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an example of an optical article of the present invention.
FIG. 2 is a schematic configuration diagram showing an example of the optical article of the present invention.
FIG. 3 is a schematic configuration diagram showing an example of the optical article of the present invention.
4A to 4F are schematic cross-sectional views showing an example of a method for producing an optical article of the present invention.
FIG. 5 is a schematic configuration diagram showing an embodiment of an image projection screen of the present invention.
FIG. 6 is a schematic configuration diagram showing an embodiment of an image projection screen of the present invention.
FIG. 7 is a schematic configuration diagram showing an embodiment of an image projection screen of the present invention.
[Explanation of symbols]
10, 20, 30: Optical component 11: Translucent base material 21, 22: Mold 31, 32 ... UV curable resin solutions 31a, 31b, 31c: First fine uneven pattern 32a ... Second fine concavo-convex pattern 100, 200, 300... Image projection screen

Claims (1)

In an optical article for projection television applications in which an optically useful fine concavo-convex pattern is formed on a translucent substrate, the fine concavo-convex pattern is formed of an ultraviolet curable resin on both surfaces of the translucent substrate, A method for producing an optical article, wherein the functional wavelength range of the ultraviolet curable resin is different on both sides,
The method for manufacturing an optical component according to claim 1, comprising at least the following steps.
(A) The process of preparing the translucent base material and the shaping | molding die in which the inversion type | mold of the 1st fine uneven | corrugated pattern was formed.
(B) The first ultraviolet curable resin solution is filled between the translucent substrate and the mold, and the entire surface is exposed from the translucent substrate side to cure the first ultraviolet curable resin solution. Process.
(C) The process of peeling the shaping | molding die in which the inversion type | mold of the 1st fine uneven | corrugated pattern was formed, and forming a 1st fine uneven | corrugated pattern in one surface on a translucent base material.
(D) The process of preparing the translucent base material in which the 1st fine uneven | corrugated pattern was formed in one surface, and the shaping | molding die in which the 2nd fine uneven | corrugated pattern was formed.
(E) The first ultraviolet curable resin between a translucent substrate having a first fine concavo-convex pattern formed on one surface and a mold having an inverted mold of the second fine concavo-convex pattern. Filling the second ultraviolet curable resin solution having a functional wavelength region longer than the functional wavelength region of the solution, exposing the entire surface from the translucent substrate side, and curing the second ultraviolet curable resin solution .
(F) The mold on which the reversal mold of the second fine concavo-convex pattern is formed is peeled off, and the first fine concavo-convex pattern is formed on one surface of the translucent substrate and the first fine concavo-convex pattern on the other surface. The process of producing the optical component in which the pattern was formed.

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