JPS63278001A - Plate lens - Google Patents

Abstract

PURPOSE:To combine a plate lens with another lens to use it most suitably and to facilitate various optical treatments by burying small lens parts, which consist of semispherical lens areas having a refractive index different from that of a synthetic resin plane plate and semispherical lens areas having a refractive index gradient, in the transparent synthetic resin plane plate having a uniform refractive index as one body. CONSTITUTION:Small lenses each of which consists of one or plural semispherical refractive index homogeneous lens area 2 having a refractive index different from that of a substrate 1 and a lens area 3 following this area 2 and having a refractive index gradient rare buried as one body in the surface of the transparent substrate formed with a synthetic resin having a uniform refractive index. Surface layers of surfaces where small lenses are formed on the plate lens have almost the same refractive index as semispherical areas 2. That is, these surface layers are uniformly constituted of a polymer having the same constitution as semispherical areas 2. Thus, this plate lens is convenient for the combinational use with another lens because the lens surface of this plate lens is flat, and the lens is easily subjected to various optical treatments.

Description

[Detailed Description of the Invention] [Field of Application in Industry A] The present invention relates to a flat plate lens, and in particular a flat plate lens formed of a synthetic resin flat plate made of a transparent body with a uniform refractive index and having a refractive index different from that of the flat plate. The present invention relates to a flat plate lens consisting of both a hemispherical lens region and a subsequent hemispherical lens region having a refractive index gradient.

[Prior Art] Conventionally, as a method of forming one lens portion or a plurality of lens portions in a line shape or matrix shape on a transparent flat plate made of synthetic resin,
Generally, a normal spherical lens is manufactured by protruding from a flat plate by means such as molding.

In addition, one or a plurality of hemispherical refractive index gradient lens portions having a refractive index distribution both in the optical axis direction and in a cross section including the optical axis are formed on a transparent flat plate made of synthetic resin in the form of a line or a matrix. Flat lenses are also known. Such a flat plate lens can be used as a peripheral device for optical communication, such as an optical coupling system between a light source and an optical fiber, or a parallel light conversion element for inserting an attenuator 1 branch circuit etc. in the middle of an optical fiber.
Alternatively, it is useful as an image transmission element in various optical system applications.

As a method for making a study of a flat lens as described above using a synthetic resin, a monomer (including a monomer mixture) Ma forming a reticular polymer (including a copolymer) Pa having a refractive index of Na, A substrate of a transparent gel object is made by partially prepolymerizing, an opening is provided in the lens part of the substrate surface and a mask is applied, and a polymer (component) having a refractive index Wb different from the refractive index Ha is inserted into the substrate through this opening. A method is known in which monomers (including monomer mixtures) Mb forming pb (including polymers) are diffused and copolymerized. In this case, if N a > N b, the lens portion formed in the substrate exhibits a concave lens effect,
If N a < N b, a convex lens effect is exhibited.

As another manufacturing method, there is a method in which a substrate of a transparent gel object similar to the above is made, a mask is applied only to the lens portion of the substrate surface, and the Mb is diffused and copolymerized from the periphery into the substrate. In this case, the lens portion formed in the substrate exhibits a convex lens effect if Na>Nb;
b indicates a concave lens effect.

[Problems to be Solved by the Invention] Among conventional flat plate lenses, in flat lenses formed by protruding a normal spherical lens on a flat plate by means such as molding, the spherical lens protrudes from the flat plate. This causes inconvenience when used in combination with other lenses, and it is difficult to perform various optical treatments on the lens.
It is also very difficult to use it in conjunction with fibers, etc.

In addition, gradient index type embedded flat plate lenses have the disadvantage that it is very difficult to form an ideal refractive index gradient from the surface layer, so post-processing such as polishing the surface layer is always required. However, it also has the disadvantage that the area of the embedded lens cannot be increased. The drawback that it is impossible to increase the area of this embedded lens portion is that if the area of the opening or mask portion provided in the substrate is increased in order to increase the area of the embedded lens portion, the This is caused by the progress of diffusion of monomeric Mb.・Furthermore, in this gradient index embedded lens, the power of the lens largely depends on the difference in the refractive index of the refractive index distribution, so in order to increase the power of the lens, the difference with the refractive index of the substrate must be extremely large. It is necessary to select a monomer Mb having a large value, but it is not easy to select such a material considering various characteristics in organic materials.

Means for Solving Problem E] The flat plate lens of the present invention has a hemispherical shape having a refractive index different from that of the flat plate in one or more parts of a synthetic resin flat plate made of a transparent body with a uniform refractive index. A small lens portion consisting of a lens region and a subsequent lens region having a hemispherical refractive index gradient is integrally embedded.

The flat plate lens of the present invention having such a configuration can be easily manufactured, for example, by the following method.

That is, first, a raw material monomer or monomer mixture Ma for a synthetic resin flat plate made of a transparent material with a uniform refractive index is prepolymerized to form a semi-polymer flat plate having one or more hemispherical recesses on the surface. form. At this time, the polymer conversion rate of the semi-polymer plate ranges from 10 to 90%.

A suitable range is preferably 20 to 80%.

Through the whole or part of the surface having this hemispherical recess,
When it becomes a polymer or copolymer, the refractive index N of the above flat plate is
A monomer or monomer mixture Mb having a refractive index Nb different from that of a is diffused into the hemispherical recess and copolymerized to be fixed. As a result, a homogeneous lens having a refractive index different from that of the flat substrate is formed in the hemispherical recess, and the region of the flat substrate following the recess is filled with the above-mentioned diffusing monomer or monomer mixture. A gradient refractive index type lens can be formed by concentration distribution, and a small lens portion consisting of both a homogeneous lens and a gradient refractive index type lens can be integrally embedded in the hemispherical concave portion, and the flat lens of the present invention can be formed. is easily manufactured.

In this case, the refractive index of each raw material mass or monomer mixture is
If Nb>Na, a convex lens is formed, and if Nb>Na, a concave lens is formed. In the present invention, the surface on which such a lens is formed is made of a copolymer having a uniform composition.

[Function] The flat plate lens of the present invention has a completely smooth lens surface, unlike a flat plate lens which is formed by protruding a normal spherical lens on a flat plate by conventional molding or other means, so it is easy to assemble with other lenses. This is convenient when used together, and it is easy to perform various optical treatments on the lens. In addition, it can be easily joined to fibers and the like.

The present invention is also suitable when it is desired to use only a part of a flat plastic plate as a lens while keeping it as a flat plate.
The range of applications can be expanded beyond the previously proposed uses.

In addition, since the flat lens of the present invention has a completely smooth lens surface and a uniform composition, it can be used for various surface modifications such as hard coating or anti-reflection using coating or vacuum technology. is also very convenient.

Furthermore, since the small lens portion of the flat plate lens according to the present invention is composed of both a homogeneous refractive index lens having a refractive index different from that of the substrate and a gradient refractive index lens, the thickness of the small lens portion can be reduced. without making it too big,
Further, the power of the lens can be increased without increasing the refractive index difference too much.

Holding such a flat plate lens of the present invention on a semi-polymer substrate having one or more concave portions, a monomer or a monomer mixture having a refractive index different from that of the substrate when turned into a polymer, When produced by diffusion and copolymerization,
The region having a refractive index different from that of the substrate and the substrate are chemically strongly bonded by copolymerization, and good adhesion and adhesion can be obtained.

Furthermore, monomers or monomer mixtures that have a refractive index different from that of the substrate when formed into polymers diffuse and enter along the surface shape of the substrate. By molding with a mold, no complicated post-processing such as polishing and removing the surface layer is required, which is extremely advantageous.

In this way, the flat plate lens of the present invention can be manufactured by special machining,
Any size without the need for polishing etc.

It is possible to mass-produce lenses with high power easily and at low cost.

[Example] Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIGS. 1(a), 1(b), and 1(C) are each schematic cross-sectional views showing one embodiment of a flat lens according to the present invention. The flat lenses shown in FIGS. 1(a), (b), and (C) each have one or more substrates on the surface of a substrate 1 made of a transparent synthetic resin with a uniform refractive index. A small lens consisting of both a hemispherical homogeneous refractive index lens region 2 having different refractive indexes and a subsequent lens region 3 having a refractive index gradient is integrally embedded, as shown in FIG.
Figure 1 (a) shows one in which one small lens is formed on one side of the substrate 1, Figure 1 (b) shows one in which a large number of small lenses are formed on one side of the substrate 1, and Figure 1 (c) shows one in which one small lens is formed on one side of the substrate 1. In this example, two small lenses are formed facing each other on both the front and back surfaces of the substrate 1. Therefore, the surface layer of each flat lens on which the small lenses are formed has a refractive index that is almost the same as that of the hemispherical region 2, that is, it is uniformly made of a polymer having almost the same composition as that of the hemispherical region 2. It is composed of

Next, a preferred manufacturing example of such a flat lens will be described. Note that the flat lenses shown in FIGS. 1(a) to (C) differ only in the number of small lenses formed and can be manufactured by the same method, so in the following,
Illustrating the method for manufacturing the flat lens shown in FIG. 1(a),
Explain in detail.

First, as shown in FIG. 2(a), a mold 5 having a hemispherical convex portion 4 having desired dimensions on its surface is prepared. The mold 5 may be made of glass, metal, or synthetic resin, preferably tetrafluoroethylene, which has good mold releasability, or may be one whose surface is coated with a suitable mold release agent.

Furthermore, a spacer made of rubber or the like is sandwiched between this mold 5 and a flat plate 6 having a smooth surface made of the above-mentioned material and fixed with clips 8. Then, as shown in FIG. 2(b), A monomer or monomer mixture Ma9 forming a network polymer or copolymer Pa having a refractive index Na is completely filled between the mold 5 and the spacer -7 using a syringe or the like.

Thereafter, this monomer Ma is prepolymerized by means such as heating, and the semi-polymer transparent gel body 9 has self-shape retention properties and has a polymer conversion rate of preferably 10 to 90%, particularly 20 to 80%.
′ is obtained.

Thereafter, the clip 8 is removed and the mold 5 having the convex portion is removed from the semi-polymer transparent gel body 9'.

Next, as shown in FIG. 2(C), a very thin spacer 10 is placed on the spacer 7, a mold 11 having a smooth surface similar to the mold 6 described above is set, and the mold is fixed again with the clips 8. Then, in the formed space 12, a monomer or a monomer mixture Mb forming a network polymer or copolymer pb having a refractive index Nb different from the refractive index Na of the network polymer or copolymer Pa is molded. Completely fill the space between 11 and spacer 10 using a syringe or the like.

Thereafter, as shown in FIG. 2(d), by heating or other means,
The above monomer M is transferred to the semi-polymer 9' consisting of the monomer Ma in the mold.
By completing the copolymerization while promoting the diffusion of b13, and then removing the molds 11 and 6 and the spacers 7 and 10, a desired flat lens as shown in FIG. 1(a) can be obtained. . This flat lens can be used as is without any post-processing.

In addition, in the present invention, the network polymer or copolymer P of the substrate
Suitable examples of the monomer Ma used to form a include diallyl esters such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diethylene glycol bisallyl carbonate; triallyl trimellidate, triallyl phosphate, and phosphorous acid. Examples include, but are not limited to, triallyl esters such as triallyl; unsaturated acid allyl esters such as allyl methacrylate and allyl acrylate; and vinyl esters such as divinyl phthalate, divinyl isophthalate, and divinyl terephthalate. Any monomer or monomer mixture that produces a transparent network polymer can be used.

゛The network polymer or copolymer Pa formed from such monomers Ma is a homopolymer obtained from the above-mentioned monomer Ma, or a copolymer obtained from two or more of the above-mentioned monomers. Polymers, and copolymers of these monomers Ma with monomers such as styrene, methacrylic acid esters, vinyl benzoate, and the like can be mentioned. ' On the other hand, the monomer or monomer mixture Mb used for forming the small lenses has a refractive index N when polymerized or copolymerized.
If b is different from the refractive index Na of the polymer or copolymer Pa of the monomer or monomer mixture Ma, even if it polymerizes to form a linear polymer or copolymer. ,
It may also form a network polymer or copolymer.

Examples of such a monomer or monomer mixture Mb include diallyl phthalate and diallyl isophthalate.

Vinyl benzoate, styrene and methacrylic esters such as methyl methacrylate, benzyl methacrylate, 2,2,2-trifluoromethacrylate, acrylic esters, vinyl acetate, vinyl chloride, acrylonitrile, butadiene or mixtures thereof are preferred. Can be used for

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

Production Example 1 As monomer Ma, diethylene glycol bisallyl carbonate (refractive index Na when turned into a polymer is 1.50)
'01) was selected as the initiator, and benzoyl peroxide (B
After adding 3% by weight of PO), as shown in Figure 2(b), use a syringe to add
A device consisting of a mold 5 having a hemispherical convex portion 4 of 5 mm and a thickness of 3 mm, a glass mold 6, and a spacer 7 was completely filled.

Thereafter, this device was placed in a constant temperature bath and maintained at 77°C for 57 minutes to obtain a semi-polymer transparent gel body 9' with a conversion rate of about 35%. Next, after carefully removing the mold 5 having the hemispherical convex portion 4, a very thin spacer 10 is placed on the spacer 7.
Figure 2 (C)
I set it like this.

After that, diallyl phthalate (refractive index Nb when it becomes a polymer is 1.572) as the monomer Mb is completely filled with a syringe from between the mold 10 and the spacer 11, and then placed in a constant temperature bath. , 5 hours at 50t, 4 hours at 60℃, 70
C. for 8 hours and then at 80.degree. C. for 7 hours to complete the copolymerization while promoting the diffusion of monomer Mb.

Finally, the molds 6 and 11 and spacers 7 and 10 were removed to obtain a desired planar convex lens having a smooth surface as shown in FIG. 1(a).

The refractive index of the homogeneous refractive index portion of this flat lens was 1.542 due to the diffusion (mutual diffusion) of the monomer Ma from the semi-polymer. The depth of the gradient index lens area is 4mm.
, the refractive index difference was 0.03.

Production Example 2 Diethylene glycol bisallyl carbonate was selected as the vehicle mass Ma, and after adding 3% by weight of diisopropyl peroxydicarbonate (IPP) as an initiator,
As shown in FIG. 2(b), a syringe is used to completely fill the device consisting of a tetrafluoroethylene mold 5 having a hemispherical convex portion 4 with a diameter of 10 mm and a thickness of 3 mm, a glass mold 6, and a spacer 7. did.

Thereafter, this device was held in a programmed drying oven, and the temperature was raised from 30°C to 60°C over 20 minutes, then held at 60°C for 20 minutes, and then lowered from 60°C to 30°C over 20 minutes. By heating, a semi-polymer transparent gel body 9' having a conversion rate of about 40% was obtained. And a mold 5 having a hemispherical convex portion 4
After carefully removing the spacer 7, a 0.5 mm thick spacer 10 is placed on the spacer 7, and a glass mold 1 with a smooth surface is placed.
1 was set as shown in FIG. 2(C).

Thereafter, 2,2,2-)-lifluoroethyl methacrylate (3FMA) (refractive index when 31 is combined is 1.4221) is used as the monomer Mb in mold 11 and spacer 10.
After completely filling the space with a syringe, the temperature was raised from 40°C to 60°C over 8 hours in a programmed drying oven.
to 70°C, then 70°C over an additional 4 hours.
After raising the temperature from 1 to 80°C, the mixture was heated at 80°C for 4 hours to complete the copolymerization while promoting the diffusion of monomer Mb.

Finally, remove mold 6.11 and spacer 7.10,
A desired planar concave lens having a smooth surface as shown in FIG. 1(a) was obtained.

The refractive index of the homogeneous refractive index portion of this flat lens was 1.445 due to the diffusion (mutual diffusion) of the monomer Ma from the semi-polymer. The depth of the gradient index lens region is 2mm.
, the refractive index difference was 0.05.

[Effects of the Invention] As described in detail above, the flat lens of the present invention has a flat lens surface, so it is convenient when used in combination with other lenses.

■ It is also easy to perform various optical treatments on the lens.

■ Can be easily joined to fibers, etc.

■ It is also suitable when it is desired to use only a part of a flat plastic plate as a lens, and the range of applications can be expanded beyond the conventionally proposed uses.

It has the following effects.

In addition, since the lens of the present invention has an extremely smooth lens surface and a nearly uniform composition, it can be used for various surface modifications such as hard coating or anti-reflection using coating or vacuum technology. It is also very convenient.

The small lens portion of the flat plate lens according to the present invention is composed of both a refractive index homogeneous lens having a refractive index different from that of the substrate and a subsequent refractive index gradient lens, so that the thickness of the small lens portion can be made very large. The power of the lens can be increased without increasing the refractive index difference or increasing the refractive index difference.

The lens of the present invention can be mass-produced easily and at low cost in any size and lens power without requiring post-processing such as special machining or polishing.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the flat plate lens of the present invention. FIG. 2 is a sectional view showing an example of manufacturing a flat lens according to the present invention. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Refractive index homogeneous lens region, 3...Refractive index gradient type lens region, 4...Semispherical convex part, 5...Type, 6.11
...Model with a smooth surface, 7.10--Spacer, 8...Clip, 9
... Monomer or monomer mixture Ma. 9'... Semi-polymer transparent gel body, 12... Space. Agent: Patent attorney Koko Shigeno [Figure (b)

Claims (4)

[Claims] (1) A hemispherical lens region having a refractive index different from that of the flat plate and a hemispherical refractive index gradient following it in one or more parts of a synthetic resin flat plate made of a transparent material with a uniform refractive index. A flat lens characterized in that a small lens portion consisting of a lens region is integrally embedded. (2) Prepolymerize the raw material monomer or monomer mixture for a synthetic resin flat plate made of a transparent material with a uniform refractive index, and coat the surface with 1
or forming a semi-polymer plate having a plurality of hemispherical recesses;
A monomer or a monomer mixture having a refractive index different from that of the flat plate when formed into a polymer or copolymer is passed through the entire or part of the surface of the flat polymer plate having hemispherical concave portions. By diffusing into the recess and copolymerizing and fixing, a homogeneous lens having a refractive index different from that of the flat base material is formed in the hemispherical recess, and in the region of the flat base material following the recess, 2. The planar lens according to claim 1, which is manufactured by forming a refractive index gradient lens by the concentration distribution of the diffusing monomer or monomer mixture. (3) The flat lens according to claim 2, wherein the semi-polymer flat plate has a polymer conversion rate of 10 to 90%. (4) The flat lens according to claim 3, wherein the semi-polymer flat plate has a polymer conversion rate of 20 to 80%.