JPH06222204A - Plastic concave cylindrical lens and its manufacture - Google Patents

Abstract

PURPOSE:To provide a concave micro-lens that has ever been developed using high polymerization resin composition and a specified high polymerization method. CONSTITUTION:A parallel light is applied on a flat resin composition which is formed with a mixture of a transparent polymer (A) and a monomer (B) capable of melting the polymer (A) and making high polymerization under the condition that a photomask with a cylindrical lens forming mask is applied to form scattered light parts 2 on the resin composition. Then scattered light is radiated with the photomask removed to form concave cylindrical lens parts 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic one-concave cylindrical lens that can be used in liquid crystal displays, optical communication devices, optical information processing devices, etc.

[0002]

2. Description of the Related Art Conventionally, a plastic cylindrical lens has been manufactured by injection molding using a mold, casting molding, or polishing a plastic original plate.

[0003]

However, in the production of the micro-cylindrical lens by such a method, it is not only extremely difficult to produce the micro-cylindrical lens, but also it is difficult to form an array of a large number of micro-cylindrical lenses. Further, in order to provide the micro-cylindrical lens with an image forming function, it is necessary to stack two cylindrical lenses with good symmetry. The present inventors have achieved the present invention as a result of earnest efforts to develop a cylindrical lens that can be easily arrayed and has at least one concave surface and good optical axis symmetry.

[0004]

The present inventors have found that polymers
(A) and the polymer (A) are dissolved, and a flat resin composition shaped a mixture of the photopolymerizable monomer (B) is irradiated with parallel light when irradiated with parallel light. Utilizing the fact that the layer structure is formed along the direction to scatter light to form a translucent body, and a plate-shaped resin coated with a photomask having a mask portion for forming a cylindrical lens portion as shown in FIG. The composition was first irradiated with parallel light to be semi-transparently polymerized and cured. At this time, polymerization shrinks due to the polymerization of the semitransparently cured portion, and the uncured portion corresponding to the mask portion becomes a concave cylindrical portion. In this state, the mask is removed, and the uncured portion is irradiated with diffused light to be transparently cured, whereby a light scattering portion as shown in the perspective view of FIG. We have succeeded in developing a plastic one-sided concave cylindrical lens consisting of a symmetric micro cylindrical lens part.

In the present invention, since parallel light is used for manufacturing a cylindrical lens, a lens having very good optical axis symmetry can be formed.

Monomers used in the practice of the present invention
(B) needs to be photopolymerizable, and among them, radical polymerizable ones are most suitable. Specific examples of the radically polymerizable monomer include methyl methacrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 2,2,3,3,4,4,5,5-octa Fluorinated alkyl (meth) acrylates such as fluoropropyl (meth) acrylate, 2,2,3,4,4,4-hexafluoropropyl (meth) acrylate and 2,2,2-trifluoroethyl (meth) acrylate ( (meth) acrylates having a refractive index of 1.43 to 1.62, for example, ethyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth).
Acrylate, hydroxyalkyl (meth) acrylate, alkylene glycol di (meth) acrylate, trimethylolpropane di or tri (meth) acrylate, pentaerythritol di, tri or tetra (meth) acrylate, diglycerin tetra (meth) acrylate, dipenta In addition to erythritol hexa (meth) acrylate, etc., diethylene glycol bisallyl carbonate, fluorinated alkylene glycol poly (meth) acrylate, urethane (meth) acrylate, etc. can be used alone or in combination of two or more. It is also possible to mix styrene, chlorostyrene, vinyl acetate and the like with the monomer (B).

Further, as the photoinitiating catalyst used for photopolymerizing these monomers (B), benzophenone, benzoin alkyl ether, 4'-isopropyl-2-hydroxy-2-methyl-propiophenone, 1-hydroxycyclohexyl phenyl ketone, benzyl methyl ketal, 2,2-diethoxyacetophenone, chlorothioxanthone, thioxanthone compound, benzophenone compound, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, N-methyldiethanolamine ,
Examples include triethylamine and the like.

It is also possible to use a thermal initiation catalyst in combination in order to complete the polymerization of the monomer (B). A peroxide catalyst is usually used as the thermal initiation catalyst.

Polymers used in the practice of the present invention
As (A), any polymer can be used as long as it is soluble in the above-mentioned monomer (B). Specific examples thereof include polymethylmethacrylate (n = 1.49), polymethylmethacrylate copolymer (n = 1.47 to 1.50), poly-4-methylpentene-1 (n = 1.46), ethylene / vinyl acetate copolymer (n = 1.46 ~ 1.50), polycarbonate (n =
1.50 ~ 1.57), polyvinylidene fluoride (n = 1.42), vinylidene fluoride / tetrafluoroethylene copolymer (n = 1.42)
42 to 1.46), vinylidene fluoride / tetrafluoroethylene / hexafluoropropene copolymer (n = 1.40 to 1.4)
6), polyfluorinated alkyl (meth) acrylate polymers and the like.

The resin composition used for carrying out the present invention needs to be shaped into a flat plate, and preferably has a viscosity of 10,000 poises or more, preferably 25,000 poises or more at room temperature.

Examples of the light source used for curing the flat resin composition in the present invention include a carbon arc lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a low pressure mercury lamp, a chemical lamp, a xenon lamp, a metal halide lamp, and a laser beam. However, in the step of irradiating the first parallel light, it is necessary to convert the light from these light sources into parallel light through the collimator lens before irradiating.

[0012]

The present invention has not been developed yet.
A plastic single-concave cylindrical lens having a light scattering portion as shown in (1) and a microcylindrical lens portion having at least one flat surface concave and having optical axis symmetry. Since the plastic cylindrical lens manufactured according to the present invention uses parallel rays in its manufacturing process, it is possible to form a cylindrical lens portion having very good optical axis symmetry. Further, this lens can be manufactured by a very simple method, and the manufacturing cost thereof is low, and there is a great merit that it is light.

Hereinafter, the present invention will be described in more detail with reference to examples.

[0014]

Example 1 Polymethylmethacrylate 50 parts by weight, benzylmethacrylate 10 parts by weight, methylmethacrylate 33
Parts by weight, 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate 7 parts by weight, 1-hydroxycyclohexyl phenyl ketone 0.25 parts by weight, and a mixture is heated and kneaded at 70 ° C to dissolve. Then, a resin composition was prepared. The viscosity of this composition was 100,000 poise at 25 ° C. This composition is sandwiched between polyester films, thickness 0.5mm, length 3cm, width 5
It was shaped like a mm flat plate. This flat shaped object is covered with a photomask as shown in FIG. 2 which has a mask portion with a length of 5 cm and a width of 1 mm which is vapor-deposited with chrome, and is irradiated with ultraviolet rays using a parallel beam type light source device (UT-501C manufactured by Ushio Inc.) did. The irradiation intensity at this time was 30 mW / cm ² , and the irradiation time was 20 minutes.
At this time, the flat resin composition portion irradiated with the parallel light became translucent, and polymerization contraction occurred, and the mask portion (lens forming portion) became concave. After that, the photomask is further removed, and the flat resin composition is irradiated with scattered light with a 40 W chemical lamp to polymerize and cure the uncured portion, and the cylindrical lens portion is transparently cured while retaining the concave portion. did it. The produced double-sided concave product had a lens function. The depth of this recess is about 2
It was 50 μm.

[0015]

Example 2 The same resin composition as that used in Example 1 was sandwiched between polyester films and shaped into a flat plate having a length of 5 cm, a width of 5 cm and a thickness of 0.5 mm. A photomask having a width of 6 cm and a length of 6 cm having a stripe pattern having a width of the mask portion of 1.0 mm and a width of the transparent portion of 0.4 mm is applied to the flat resin composition, and light irradiation is performed in the same manner as in Example 1. It was The obtained cylindrical lens has a lens part of 1.0 mm and a light diffusion part of 0.4 m.
It was an m 2 cylindrical plastic lens array with both sides concave made of plastic. The depth of the concave surface of this cylindrical lens was 40 μm on both surfaces. Moreover, each cylindrical lens had uniform performance.

[0016]

[Comparative Example 1] Same thickness as that produced in Example 1 0.5 mm
The plate-shaped resin composition of (1) was irradiated with light from a 40 W chemical lamp for 20 minutes while a photomask similar to that used in Example 1 was applied. At that time, formation of an opaque portion was not observed in the light-irradiated portion of the flat resin composition.

[0017]

Example 3 A resin mixture consisting of 50 parts by weight of polymethylmethacrylate, 30 parts by weight of methylmethacrylate, 20 parts by weight of 2,2,3,3-tetrafluoropropylmethacrylate and 0.25 part by weight of 1-hydroxycyclohexylphenylketone was used. A resin composition was prepared by heating and kneading at 0 ° C. to dissolve. This resin composition had a viscosity of 125 thousand poise at 25 ° C. This resin composition was sandwiched between polyester films and shaped into a flat plate having a length of 3.5 cm, a width of 3.5 cm and a thickness of 1 mm. A width having a stripe-shaped pattern having a mask portion width of 0.5 mm and a transparent portion width of 0.2 mm on the flat resin composition 3.
A photomask of 5 cm 3 and a length of 3.5 cm was applied, and by the same operation as in Example 1, first, parallel light was irradiated and then scattered light was irradiated except for the photomask. Lens section 0.5 mm,
A flat plastic biconcave cylindrical lens array with a light diffusing section of 0.2 mm was produced. The depth of the concave surface of this cylindrical lens was 25 μm on each side. Also, each lens had uniform performance.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a plastic micro-cylindrical lens of the present invention.

FIG. 2 is a plan view showing an example of a photomask used for making the cylindrical lens of the present invention.

[Explanation of symbols]

 1 ………… Concave cylindrical lens part 2 ………… Diffusion part 3 ………… Mask part of photomask 4 ………… Transparent part of photomask

Claims (2)

[Claims] 1. A light-scattering portion in the plane of a plastic flat plate,
A plastic aspherical cylindrical lens having a microcylindrical lens portion having at least one concave surface of the flat plate surface and having optical axis symmetry. 2. A polymer (A) and the polymer (A) are dissolved,
And, in a state in which a photomask having a mask portion for forming a micro-cylindrical lens is applied to a plate-shaped resin composition comprising a photopolymerizable monomer (B), the resin composition is irradiated with parallel light. The first step of curing the light irradiation part semi-transparently and forming a minute concave surface having a lens function in the mask part by polymerization shrinkage, and then irradiating the flat resin composition with diffused light in the state where the photomask is removed Then, in the first step, a portion having an uncured lens ability is cured, and a method for producing a plastic micro-cylindrical lens, characterized in that: