JPS5959421A - Manufacture for plastic plane lens - Google Patents

Abstract

PURPOSE:To obtain surely a plane lens with stable quality by polymerizing the polymers with different refractive indexes on the base material containing protrusions and depressions, which making transparent gel-base material by partially polymerizing the monomer forming reticulated material. CONSTITUTION:Transparent gel-base material is made by partially polymerizing a monomer Ma forming the reticulated polymer Pa with refractive index Na. Then, e.g. the cone shape protrusions 2 projecting on the base material correspondingly to the lens part of refractive index distribution type, are formed at one side 1A of the base material as one body with the base material. The width D, at the root part of this protrusion 2 is caused to be consistent with the diameter of the predetermined lens part. Then, the monomer Mb forming the polymer Pb with the refractive index Nb different from the refractive index of the reticulated polymer, is diffused and polymerized into the base material from the forming surface-side of the protrusion 2. Next, the protrusion 2 is cut off on the same level as that of the plane part 1A of the base material and the plane is finished by polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a lens body in which a gradient index lens portion is formed in a transparent substrate made of synthetic resin.

flat? A refractive index distribution that changes approximately to the seventh power in the direction of the optical axis in a transparent substrate having a flat surface, and a refractive index distribution that gradually changes approximately to the square power as the optical axis moves away from the optical axis within at least one cross section including the optical axis. A flat plate lens is known in which a large number of gradient index lens portions having a gradient index are formed at intervals in a linear pattern.

The lens part may be a circular lens with a refractive index distribution as described above in all cross sections including the optical axis, or it may be a circular lens with a refractive index distribution that gradually changes as the distance from the optical axis increases within seven cross sections. In some cases, the lens is a so-called semi-cylindrical lens whose refractive index is constant regardless of the distance from the optical axis within a cross section perpendicular to this.

A series of flat lenses are used as image transmission elements in a variety of applications, such as the optical systems of copying machines and facsimile machines, or as optical coupling systems between light sources and optical fibers.

It is useful for peripheral devices for optical communications, such as parallel light conversion elements for inserting attenuators or branch circuits in the middle of optical fibers.

When manufacturing a flat lens as described above using a synthetic resin, monomers (monomer mixtures) forming a network polymer (including copolymers) Pa with a refractive index of Na are used as shown in Figure O9. A substrate 100 of a transparent gel object is made by partially polymerizing Ma (including Ma), and a mask 10.2 is applied by providing an opening 10/ in the lens portion on the substrate surface 100, and the above-mentioned refractive index Na and A known method is to carry out diffusion polymerization of monomers (including monomer mixtures) Mb to form polymers (including copolymers) pb with different refractive indexes Nb.

In this case, if Na>Nb, the lens portion 103 formed in the substrate will have a concave lens effect, and if Na<Nb, it will have a convex lens effect.

In addition, as shown in Figure 1, a substrate 70 of a transparent gel object similar to that described above is made using another method, and a mask 105 is applied to the lens portion of the substrate surface to limit the lens area.
There is also a method of diffusing a monomer that is polymerized with Nb and has a refractive index different from that of Na.

In this case, the lens portion 10B formed in the substrate exhibits a convex lens effect if Na>Nb.1. Na＞
Nb exhibits a concave lens effect.

In the conventional method as described above, monomer Mb is It enters between the mask and the gel substrate,
Monomer Mb diffuses over the entire surface of the gel substrate,
There is a problem that a lens body cannot be formed.

The present invention aims to solve the above-mentioned conventional problems and to provide a novel method for manufacturing a plastic flat lens that can avoid the problem of adhesion between a mask and a gel substrate in the manufacturing process of a gradient index flat lens. There is.

In the method according to the present invention, first, monomers (including monomer mixtures) M that form a network polymer (including copolymers) Pa
A transparent gel substrate is made by partially polymerizing a. At this time, a protrusion integral with the substrate or a recess with a sharp bottom is provided corresponding to the lens portion.

Preferred examples of the monomer Ma used in the present invention include diallyl phthalate and diallyl isotucrate.

Diallyl esters such as diallyl terephthalate, diethylene glycol bisallyl carbonate; triallyl trimellidate, triallyl phosphate.

Triallyl esters such as triallyl phosphite; unsaturated acid allyl esters such as allyl methacrylate and allyl acrylate; divinyl phthalate, divinyl inphthalate,
Examples include, but are not limited to, vinyl esters such as dibyl terephthalate, and any monomer that produces a transparent network polymer can be used.

Further, the network polymer used in the present invention is a homopolymer obtained from the monomer Ma as described above.

or copolymers obtained from two or more of these monomers, and copolymers of these monomers Ma with monomers such as styrene, methacrylic acid ester, or vinyl ammonium fluoroate, etc. is appropriate.

In the present invention, the protruding portion that is formed integrally with the substrate surface so as to protrude above the substrate serves a masking function when the monomer that changes the refractive index of the substrate is diffused and double-polymerized into the substrate.

Further, when a concave portion with a sharp lower base is provided, the lower base of the concave corresponds to the conventional masking opening, and the portion of the substrate located above the lower base performs the masking function.

The protrusion or recess is formed locally in a location where the gradient index lens portion is to be provided, and the plan view shape of the cross section parallel to the substrate surface at the base of the protrusion or the recess is shaped into the shape of the lens. Almost match. For example, when forming a circular lens, the cross section of the protrusion or recess is circular, and when forming a semicylindrical lens, it is formed into an elongated protrusion or groove.

There are no particular restrictions on the side shape of the protrusion, and it may be, for example, a cone that tapers from the base to the upper end.

In addition to having a shape like a truncated cone, the shape may have seven shapes with a uniform diameter or width from the base to the upper end. Further, in some cases, the diameter or width may be larger at the upper end than at the base.

However, when producing a gel substrate with protrusions according to the present invention by casting using a mold, it is convenient to make the protrusions tapered at the upper end so that they can be easily removed from the mold.

When a recess is provided instead of a protrusion, it is desirable to have a relatively large entrance width for the recess so as to facilitate cast molding, and to provide a taper that continuously narrows toward the bottom.

Next, a polymer (
A monomer (including a copolymer) forming Pb (including a polymer mixture) 14b is diffused and polymerized, and then the substrate surface is planarized so as to remove the protrusions or recesses.

The monomer Mb used in this process may be one that polymerizes to form a linear polymer or one that forms a network polymer.

As such monomer Mb, styrene, methacrylic acid ester, atarylic acid ester, vinyl a-acid, hinyl chloride, acrylonitrile, butadiene, or a mixture thereof can be suitably used.

Next, the present invention will be described in detail based on embodiments shown in the drawings.

First, as shown in the figure, a monomer Ma forming a network polymer pa having a refractive index of Na is partially polymerized to form a transparent gel substrate.
Create.

At this time, a conical protrusion 2 is integrally formed between the substrates as an example of protruding onto the substrate surface in correspondence with the gradient index lens portion on one side of the substrate 1A.

The diameter at the base of this protrusion m2 is approximately matched to the diameter of the intended lens portion.

If the height HIK of the protruding part of the mouth is too small, when the monomer that changes the refractive index is diffused, the diffusion rate will be almost uniform over the entire surface of the glass plate, and the optical axis (substrate Since the refractive index distribution proportional to the distance from the surface normal (the surface normal) becomes sufficiently narrow, it is desirable that H] be less than /mm.

Next, from the side where the protrusion 1 is formed, the refractive index N of the network polymer pa is different from the refractive index Na, for example smaller than Na.
JitffKMb forming polymer Pb of b is diffused into the substrate and polymerized.

At this time, monomer Mb diffuses into the interior from the plane part /A of the substrate / and the surface part 2A of the protrusion part -, and in the process,
In the base of the protrusion -, the diffusion and permeation of the monomer is delayed compared to the plane part/A-direction F part, so the concentration distribution of the monomer Mb is 1, that is, the same -Irr (the distribution plane connecting the refractive index parts is O/
As shown in the figure, a hemispherical swelled distribution is formed just below the base of the protrusion 1s, 2σ).

Next, adjust the protrusion d''1 to the level (b) of the flat part of the board/A.
Section 2 is cut out and polished to a flat surface.

As a result, light ll1ll perpendicular to the substrate surface enters the substrate.
I3, and a refractive index distribution in which the refractive index power increases continuously by 1 in the direction of the optical axis 3, and a refractive index distribution in which the refractive index power decreases as it moves away from the optical axis 3 in a virtual plane parallel to the substrate surface. A lens portion l having a convex lens action is formed.

If a monomer Mb having a refractive index of Na<Nb is used in the process described in item 1, the lens portion l will have a concave lens effect.

Another embodiment of the present invention is shown in the diagram.

In this example, a transparent gel substrate 10 is made by partially polymerizing the monomer Ha that forms the refractive index NaO network polymer pa, and the substrate 10 is formed at the same time as the tJ molding or after the substrate is formed by drilling, etc. , to the gradient index lens part;
/ to form.

If the depth H2 of this concave portion // is too small, when the monomer that changes the refractive index is diffused, the diffusion rate will be almost uniform over the entire substrate surface, and the optical axis (four plate surfaces Since the refractive index distribution proportional to the distance from the normal line cannot be sufficiently obtained, it is desirable to set H2 to 7 mm or more.

Next, from the forming surface side of the recessed portion //, for example, NaJ: a smaller refractive index Nb than the refractive index Na of the net-like combined body Pa.
forming a polymer pb of 1i51f1. The body +4b is diffused into the substrate and incorporated.

At this time, +)'Lm body Mb is the entire inner wall surface of the recess //
It diffuses into the substrate from A, but 1・bottom//B"1
Street J, li & nihei? 7 Virtual Plane 7.2 Funeral 1
1 (The concentration distribution of body Mb is highest at Fi 戊//B, and as it moves away from the [bottom//B of the eye, the diffusion from the inner wall surface//A is delayed accordingly, so the concentration decreases.

In this way, by polishing etc., the above virtual surface /,,! If you remove the IOA for -1 board tfl1 and move it downwards -4, the remaining board part 10B will have a light rlal that is the center line of the concave part //.
+ / 3, and this light has a refractive index distribution in which the refractive index is continuous in the 4i+l+ direction and changes like 'c', and F'l on the substrate surface.
'7r virtual reality is 9111! A lens portion/da is formed having a refractive index distribution in which the refractive index JJi changes continuously as it moves away from I/ and Te.

In this case, if the refractive index relationship is Na>Nb, this lens portion /q has a concave lens effect, and if Na<tvb, it has a convex lens effect.4. It has a river.

By providing a large number of conical protrusions (or inverted conical recesses) at intervals on a single substrate as described above, a plastic plate lens constituted by a 1iil gradient index lens arrangement can be obtained. but? Tl will be done.

In addition, as shown in Fig. 71 or Fig. It is also possible to manufacture a tJj index distribution type surface lens equivalent to the Kamapoko 1 lens or the Kira lens.

Above (/this method of the present invention explained (・koyo11!4zo)1
．． ), [It is necessary to mask the foreign material < , l1ii The refractive index changes due to the diffusion of the ill 17j body, which increases the feeding rate due to the unevenness of the substrate itself.) -C
ll1i(3) How to do 1 - Since there is C, there is K as before.
J+ (flat lenses of stable quality can be reliably manufactured without causing problems such as defective formation of the lens portion due to poor adhesion between the plate and the mask layer).

Furthermore, by selecting the striped shape of the protrusions or recesses, it is extremely easy to control the refractive index distribution in the direction perpendicular to the optical axis.

Example / Diethylene glycol bisallyl carbon + Iζ nate (O
R-J9) Km oxidized Henzoino b (BPO) by weight 3
903) Opening force [1
Heat it, and in the figure]) 1 == J mm + H
]=” ” m was prepared. The surface K1 of this gel object. /, 3-) 1) Hydrin (-)Roro7°rohydrin methacrylate (4'FMA) was brought into contact and held at SOoC for 60 minutes, then the temperature was raised to O'CK/maintained during the evening sky. Next, the iMA that had been hardened 17 together with the hardened object was scraped off along with the protruding part of the object, and the remaining part was polished.
A block made of OR-39 was obtained in which UFMA was diffused in parts other than the center. The central part of this block has a 6-o convex lens and t
J, and the focal length was approximately 1 fCm.

Example! Diethylene glycol bisallyl carbonate-1 (OR
-39) and 3% by weight of bency peroxide/BPo)
Dissolve it, pour it into a mold, and heat it for 90 minutes at O''C.
A gel object having a diameter of mm was prepared. Hensyl methacrylate-1 (B
ZMA) was brought into contact and held at 50°C for 60 minutes, then the temperature was raised to go'c and held for 73 hours.

Next, the hardened BZM fi with the gel object was scraped off to the position of surface 7.2 in the square diagram, the remaining part was layered, and a block made of 0R-39 with the center K BZI A diffused was made. It was good. The center of this block is a convex lens with a focal length of approximately iocm.

Example 3 Henzyl peroxide (BPO) was dissolved at 3% by weight in Allyl Iso7 Taret (110AIP) and poured into a mold.
Heated for 110 minutes at oC, DI = 3 at o/Fig.
A gel body with H1=47 mm was prepared. The surface i of this gel object on the side where the protrusion - is provided? iu
? m /, /, 3-) IJ Hydropar 70 loprovir methacrylate (4 (FMA) in contact with SOo
C and held for 90 minutes, then wetted and held for S hours. Next, the surfaces of the flat parts of these resin bronzes were polished. Inside the focus lll'i separation! A convex lens of mm was generated. Next, after removing the protruding parts of this resin block and polishing them, the focal length of this lens was 10CT11 and f7.

Example: Dissolve 3% by weight of hensoil peroxide (BPO) in (DAIp), pour into a mold and heat at 0°C for 0 minutes.
A gel object was prepared in which H2=LJ mm and H2=LJ mm. The concave portion of this gel object//on the forming surface/, /, 3
-) Contact with IJ Hydro Nogu-70 Lob Pill Methacrylate (GFMA) and hold at 0°C for 60 minutes,
The temperature was then raised to O''C and held for 75 hours.Then, the concave portion//forming surface of this resin block was heated to the concave portion//
After scraping and polishing until it completely disappeared, the block had a single concave lens at the center '1f1, with a focal length of approximately 77 mm.

[Brief explanation of the drawing]

Figures 7 to 3 show an embodiment of the present invention. Figure 7 is a side sectional view of the substrate after the cadaver diffusion treatment, Figure 2 is a cutaway perspective view of the same essential parts, and Figure 3 is Figures 7 to 7 show other embodiments of the present invention; a side sectional view of a single M1 body j7, a side sectional view of a substrate after being subjected to destruction treatment; The fragmented perspective view of the main part, the side cross-sectional view, the off view, and the cross-sectional view of the obtained flat lens are the substrate tit shape when a flat lens with a semicylindrical lens function is made by the method of the present invention. 9 and 0 are cross-sectional views showing a conventional method for manufacturing a gradient index plane lens. /, 10...Substrate -...Protrusion 3...
...optical axis, /<7 ...gradient index lens section // ...concave portion Fig. 1 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 8 Prisoner Fig. 9 Fig. 103I ○31o3 Figure 10 +06 106 106 Procedural Amendment/Indication of Case Patent Application Sho, lt7-/701. ! ;Method of manufacturing No. 1 plastic flat lens 3 Relationship with the case of the person making the amendment Patent applicant address 4-8 Doshomachi, Higashi-ku, Osaka-shi, Osaka Name Name
(3oo) Nippon Sheet Glass Co., Ltd. Representative Toga
Nobuo Yuri Agent 7 Contents of the amendment 1) In the 12th line of page 1.2 of the specification tube, the text ``zo/shi substrate'' should be amended to ``gel substrate.'' s) gfl thin 4@paper+%”@wa*”cT? r l:
'Na) N9 hiih3M fs 'N. (Nl,, I'm going to go to bed tonight. PL2

Claims (1)

[Claims] A single transparent plastic substrate having both a refractive index distribution that gradually changes in the optical axis direction and a refractive index distribution that gradually changes as the distance from the optical axis increases within at least one cross section that includes the optical axis. A reticular polymer (including a copolymer)
A transparent gel substrate is made by partially polymerizing the monomers (including monomer mixtures) that form the gel, and at this time, a protrusion integral with the substrate or a recess with a sharp bottom is formed to correspond to the lens part. A monomer (including a monomer mixture) that forms a polymer (including a copolymer) having a refractive index different from that of the network polymer on the substrate surface including the protrusion or recess is provided. A method for manufacturing a plastic flat lens, comprising the steps of diffusing and polymerizing, and then flattening the substrate surface to remove the protrusion or surrounding portion.