JPH06160609A - Biconcave faced cylindrical lens made of plastic and its production - Google Patents

Abstract

PURPOSE:To provide the cylindrical lens made of plastic having a lined concave faced lens part. CONSTITUTION:A photomask having a cylindrical lens pattern is pressed to a flat planar material formed by molding a mixture composed of a polymer (A) and a monomer (B) which can form a polymer varying in refractive index from this polymer (A) and this material is irradiated with parallel rays of light from the photomask surface; thereafter, the photomask is removed and further, the material is irradiated with diffused light in this state, by which the flat planar resin compsn. is cured and the biconcave lens-shaped cylindrical lens part 1 is formed within the flat planar surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic biconcave cylindrical lens that can be used in liquid crystal displays, optical communications, optical information processing, etc., and a method for manufacturing the same.

[0002]

2. Description of the Related Art A cylindrical lens made of plastic has hitherto been manufactured by molding a plastic or polishing a plastic plate.

[0003]

However, it is difficult to form a lens array in a lens manufactured by such a method for manufacturing a cylindrical lens. Further, in order for the cylindrical lens to have a double-sided image forming function, optical axis symmetry of the light entrance / exit surface of the cylindrical lens is required, and it is necessary to accurately superpose lens members having two symmetries. , This work was extremely difficult.

[0004]

Means for Solving the Problems The inventors of the present invention have made earnest efforts to develop a cylindrical concave lens having a biconcave surface and good optical axis symmetry. It was

The gist of the present invention is to provide a flat plate-like product comprising a polymer (A) and a uniform transparent mixture of the polymer (A) and a photopolymerizable monomer (B). A photomask having a linear mask portion as shown in FIG. 3 is brought into contact with the resin composition of FIG. 3 on a plane, and parallel rays are irradiated to polymerize and cure a portion of the flat resin composition other than the mask portion. Let it be done. At this time, portions of the flat plate other than the photomask are hardened to be semitransparent, and the mask portion forms line-shaped concave portions having optical axis symmetry. In this state, the photomask is removed, and the entire flat plate is irradiated with diffused light to cure the uncured portion, whereby the cylindrical lens of the present invention can be obtained.

As shown in the sectional view of FIG. 1 and the perspective view of FIG. 2, the cylindrical lens of the present invention has a light scattering portion 2 in a flat plate, and both sides of the flat plate are concave and have optical axis symmetry. It has a line-shaped transparent plastic cylindrical lens portion 1.

The lens portion of the cylindrical lens of the present invention uses photopolymerization by parallel light at the initial stage of photopolymerization of a flat plate of the photopolymerizable composition in the manufacturing process thereof.
The optical axis symmetry of the formed lens portion is extremely good.

The monomer (B) used in the practice of the present invention must be photopolymerizable and have the ability to dissolve the polymer (A). Of these, radical polymerizable ones are most suitable. Is. Specific examples of the radical photopolymerizable monomer (B) include methyl methacrylate, 2,2,
3,3-tetrafluoropropyl (meth) acrylate, 2,
2,3,3,4,4,5,5-octafluoropropyl (meth) acrylate, 2,2,3,4,4,4-hexafluoropropyl (meth) acrylate
Acrylate, fluorinated alkyl (meth) acrylate (n = 1.37 to 1.44) such as 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, dipentaerythritol hexa (meth) acrylate, etc., as well as diethylene glycol bisallyl carbonate,
Examples thereof include fluorinated alkylene glycol poly (meth) acrylate, urethane-based (meth) acrylate, styrene, chlorostyrene, vinyl acetate, etc. These monomers (B) may be used alone or as a mixture of two or more kinds. You can

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

Further, in order to complete the polymerization of the monomer (B), a thermal initiation type catalyst may be incorporated together, and a peroxide type catalyst is usually used as this thermal initiation type catalyst.

As the polymer (A) used in carrying out the present invention, any polymer can be used as long as it is soluble in the monomer (B) and forms a transparent resin composition. For example, polymethylmethacrylate (n =
1.49), polymethylmethacrylate copolymer (n = 1.47)
~ 1.50), poly-4-methylpentene-1 (n = 1.46), ethylene / vinyl acetate copolymer (n = 1.46 to 1.50), polycarbonate (n = 1.50 to 1.57), polyvinylidene fluoride (n =)
1.42), vinylidene fluoride / tetrafluoroethylene copolymer (n = 1.42 to 1.46), vinylidene fluoride / tetrafluoroethylene / hexafluoropropene copolymer (n =
1.40 to 1.46), polyfluorinated alkyl (meth) acrylate polymers and the like.

In order to produce an opaque cured resin by irradiating a resin composition of the polymer (A) and the monomer (B) with parallel light, the refractive index of the polymer (A) and the monomer ( The difference from the refractive index of the resin obtained by polymerizing B) is at least 0.001 or more, preferably 0.00
It is necessary to make it 5 or more.

In order to produce the cylindrical lens of the present invention using the resin composition, it is necessary to mold the resin composition into a flat plate having no optical distortion. In order to produce a flat resin composition having no optical distortion, the viscosity of the resin composition at room temperature is preferably 10,000 poises or more, and more preferably 25,000 poises or more.

As a light source that can be used when the resin composition is irradiated with light to be cured, a carbon arc lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a low pressure mercury lamp, a chemical lamp, a laser beam or the like can be used. The light emitted from these light sources is usually diffused light, and in order to obtain parallel light using these light sources, the light from these light sources may be passed through a collimating lens.

In order to produce the cylindrical lens of the present invention, a flat-shaped molded product of the above-mentioned resin composition is provided, for example, as shown in FIG.
~ A photomask as shown in Fig. 5 is brought into contact, and parallel light rays are irradiated from the upper surface of the photomask to cure the portions of the flat resin composition other than the mask portion while making them opaque, and at the same time, the flat resin composition mask is used. Part is formed with an optical axis symmetric type uncured concave lens part, and then the photomask is removed, and the entire surface of the plate-shaped resin composition is irradiated with diffused light to be completely cured, whereby the cylindrical object of the present invention is obtained. It can be a lens.

[0016]

The present invention has never been developed,
The cylindrical lens portion 1 is provided in a flat plate having a light scattering portion 2 as shown in FIG. 1, and both surfaces of the flat plate of the cylindrical lens portion are concave and are made of a transparent body having optical axis symmetry. Since the plastic biconcave cylindrical lens of the present invention uses parallel rays,
The optical axis symmetry is very good. It can also be produced by a very simple method.

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

[0018]

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. A resin composition having a viscosity at 25 ° C. of 100,000 poise was prepared. This resin composition was sandwiched between polyester films and shaped into a flat plate having a thickness of 0.5 mm, a length of 3 cm and a width of 5 mm. As shown in FIG. 3, a line mask portion having a length of 5 cm and a width of 1 mm was abutted on the flat shaped object by a chromium vapor deposition method, and a parallel light beam type light source device (manufactured by Ushio Inc., It was irradiated with ultraviolet rays using UT-501C).
The irradiation intensity at this time was 30 mW / cm ² , and the irradiation time was 20 minutes. The part of the resin composition irradiated with the parallel light became semitransparent and the mask part became concave. After this, remove the photomask from the flat resin composition surface,
When the uncured portion was polymerized and cured by irradiating it with a 40 W chemical lamp, it could be cured transparently while holding the linear concave portion. The produced double-sided concave portion had a lens function. The dent of this concave portion was about 50 μm on both sides from the flat portion.

[0019]

Example 2 The resin composition used in Example 1 was 5 cm in length,
It was shaped into a flat plate with a width of 5 cm and a thickness of 0.5 mm. This flat shaped object has a line-shaped mask width of 1.0 mm and a transparent area of 0.4 mm.
A photomask having a width of 6 cm and a length of 6 cm as shown in FIG. A flat plastic biconcave cylindrical lens array having a width of the cylindrical lens portion of 1.0 mm and a light diffusion portion of 0.4 mm could be manufactured. The concave indentation of this cylindrical lens was 40 μm on both sides. Also, each lens had uniform performance.

[0020]

Comparative Example 1 The photomask used in Example 1 was brought into contact with the 0.5 mm thick flat plate resin prepared in Example 1, and diffused light irradiation was performed for 20 minutes with a 40 W chemical lamp. At that time, no concave surface was formed and no opaque portion was formed.

[0021]

Example 3 A mixture of 50 parts by weight of polymethyl methacrylate, 30 parts by weight of methyl methacrylate, 20 parts by weight of 2,2,3,3-tetrafluoropropyl methacrylate and 0.25 parts by weight of 1-hydroxycyclohexyl phenyl ketone was added at 65 ° C.
Was heated and kneaded and dissolved to prepare a resin composition. This resin composition had a viscosity at 25 ° C. of 125,000 poise. This resin composition is sandwiched between polyester films,
It was shaped on a flat plate with a length of 3.5 cm, a width of 3.5 cm, and a thickness of 1 mm. In this flat shaped object, the width of the mask part is 0.5 mm and the width of the transparent part is 0.
Figure 4 with 5mm length and 5cm width with 2mm mask pattern
A photomask as shown in (1) was brought into contact with the substrate, and the same photopolymerization operation as in Example 1 was performed. A flat plastic biconcave cylindrical lens array having a lens portion width of 0.5 mm and a light diffusion portion width of 0.2 mm could be manufactured. The concave indentation of this cylindrical lens was 25 μm on both sides. Also, each lens had uniform performance.

[0022]

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a cylindrical lens of the present invention.

FIG. 2 is a perspective view showing an example of a cylindrical lens of the present invention.

FIG. 3 is a plan view of an example of a photomask.

FIG. 4 is a plan view of an example of a photomask.

FIG. 5 is a plan view of an example of a photomask.

[Explanation of symbols]

 1 …………………… Cylindrical lens part 2 …………………… Light opaque part 3 …………………… Mask part of photomask 4 …………………… Light-transmitting part of photomask 5 …………………… Photo mask

Claims (2)

[Claims] 1. A plastic double-sided concave cylindrical body, wherein a transparent cylindrical lens portion having concaves on both sides of the flat plate and having optical axis symmetry is formed in a plastic flat plate having a portion for scattering light. lens. 2. The polymer (A) and the polymer (A) can be dissolved and photopolymerized, and the refractive index of the obtained polymer is different from that of the polymer (A). The plate-shaped resin composition in which a uniform mixture with the monomer (B) is shaped is irradiated with parallel light while being in contact with a photomask having one or more linear light-impermeable parts. The part other than the mask part is semi-transparently cured, and the part other than the mask is polymerized to form a minute concave surface with concave lens function in the masked part, then remove the photomask from the flat plate surface and A method for manufacturing a plastic cylindrical lens, which comprises irradiating diffused light onto the surface of the flat plate to photopolymerize and cure the uncured portion.