JPS6247001A - Production of optical element - Google Patents

Abstract

PURPOSE:To form an org. optical element having an optional refractive index distribution and optional size at a high grade and low cost by supplying a powder mixture material consisting of org. powder materials at varied mixing ratios to a molding device and forming a molding having the change in the mixing ratios in the radial direction. CONSTITUTION:The org. powder materials 1, 2 which are different from each other are put into vessels 3, 4. A fan 8 for blasting and a fan 9 for mixing are run and poppets 5, 6 are operated to release the materials 1, 2 into a transport pipe 7. The mixed org. powder material 10 is transported and is sent into a molding device 11 having a rotor shape. The space on the outside of the device 1 is sucked by a suction pump 16 through a discharge pipe 15. The material 10 is pressed to a filter 12 by centrifugal force and flow when the device 1 is rotated. The material 10 is then deposited on the filter 12 and a mixed org. powder layer 20 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing an organic optical element having an internal refractive index distribution with high quality and at low cost.

(Prior art) Conventionally, organic optical elements made of plastic lenses, etc.
It is widely used in the optical wave L'pj field because of its various advantages such as light weight, high V11 impact resistance, easy molding, no polishing required, inexpensive material, and low manufacturing cost. It has become.

In addition, such organic optical elements are generally required to have various performances such as being colorless, having no bubbles, being free from distortion, and having a high refractive index. At the same time, there is also a demand for a new optical element that has a refractive index distribution inside it, for example, in the optical axis direction or radial direction.

As a method for obtaining such an organic optical element having an internal refractive index distribution, for example, (1) diffusing an organic substance different from that of the optical element from the surface of the optical element once formed into the element; A method of forming a concentration gradient of the organic substance in an optical element, and (2) a method of copolymerizing different monomers to form a concentration gradient of the constituent monomer concentrations are known.

(Problem to be solved by the invention) The diffusion method in Section 42 (1) is a method in which the diffusion of organic matter is controlled by the temperature of the system, the concentration of organic matter, etc., and a concentration gradient of organic matter is formed within the optical element. However, this method is possible to some extent with thin optical elements because the diffusion of organic substances within the optical element is slow, but it cannot be applied industrially to relatively large optical elements, and the concentration on the surface is low. Although it can be controlled to some extent, it is almost impossible to control the central part of the optical element. Therefore, such a diffusion method cannot meet the demands of the conventional technology.An example of the method (2) above is to half-polymerize (incompletely polymerize) the raw monomer in a predetermined mold to form a gel-like molded product. In this method, the molded body is impregnated with other heptamers and copolymerized, but this method involves controlling incomplete polymerization of raw monomers, controlling the impregnated concentration of other monomers, and controlling the interaction between these heptamers. It is difficult to control copolymerization, and there are various restrictions such as monomers being limited to those that are copolymerizable with each other.

It is far from practical application.

Another copolymerization method involves mixing two or more monomers with different polymerization rates and photopolymerizing the mixture, first depositing a polymer made of monomers with a high polymerization rate on the wall of the container, then depositing a copolymer, and finally However, like the above-mentioned methods, it is difficult to control the various conditions in these methods, and their industrial value is low. Furthermore, in any of these methods, unreacted monomers exist in the system.

Another problem arises due to volatilization of the powder after molding.

Therefore, an object of the present invention is to provide an organic optical element of any size having any refractive index distribution with high quality and at low cost, without any particular restriction on the organic material used.

In order to solve the problems of the prior art as described above and achieve the purpose of the present invention, the inventor of the present invention, as a result of intensive research, prepared two or more types of organic powder materials and mixed them while changing the mixing ratio. The present invention was completed based on the finding that the above-mentioned problems of the prior art can be solved by manufacturing an optical element by supplying and molding the optical element.

(Disclosure of the Invention) That is, 1 the present invention uses two or more types of organic powder materials, supplies a powder mixture material with a varying mixing ratio to a molding machine, and molds the material in which the mixing ratio changes in the radial direction. This is a method for manufacturing an optical element, which is characterized in that the optical element is made into a material, and is solidified and made transparent as necessary.

The principles of the invention will now be explained in more detail with reference to the accompanying drawings, which schematically illustrate one preferred embodiment of the invention.

FIG. 1 shows a preferred method for mixing two types of organic powder materials while changing the mixing ratio and supplying the mixture to a molding machine. 2 represents a particular organic powder material, 2 is present in the container 4;
5 and 6 represent poppets that adjust the mixing ratio of the organic powder materials 1 and 2 by adjusting the amounts of the organic powder materials 1 and 2 released. Poppets 5 and 6 are.

This is an example of a preferred means for supplying organic powder materials 1 and 2 from containers 3 and 4.

7 is a transport pipe for the organic powder material, and 8 is a blower fan for moving the organic powder material therein. 9 is a mixing fan for mixing organic powder materials 1 and 2, and 10 is an organic powder material mixture consisting of organic powder materials 1 and 2.

For convenience of explanation, two types of organic powder materials will be used.

Different organic powder materials 1 and 2 are placed in containers 3 and 4.
Put in. Rotate the ventilation fan 8 and the mixing fan 9,
Poppets 5 and 6 are actuated to discharge organic powder materials 1 and 2 into transport tube 7. The organic powder materials 1 and 2 are directed by the blowing fan 8 to the mixing fan 9 on the downstream side, thereby being transported in a mixed state 10.

The mixing ratio of organic powder materials 1 and 2 in this mixed state IQ can be arbitrarily controlled by poppets 5 and 6.

The mixed organic powder material IO is transported and fed into a rotor-shaped former 11, a preferred example of which is shown diagrammatically in FIG. The space outside the molding device 11 is also suctioned through the exhaust pipe 15 by a suction pump 16 .

A filter 12 is provided on the side of the molding device 11, and when the molding device 11 is rotated, the mixed organic powder material 10 is pressed against the filter 12 by centrifugal force and flow.

A mixed organic powder material 10 is deposited on the filter 12 to form a mixed organic powder layer 20. This mixed organic powder layer 2
0 will have a distribution of mixing ratios adjusted by the popents 5 and 6 illustrated in FIG. Therefore, ho.

The organic powder material t can be prepared by adjusting the pastes 5 and 6.
The mixing ratio of -11 and 2 can be freely changed.

In the above method, the temporary coagulant 17. For example, it is preferable to spray a liquid such as water or an organic solvent, a solution or dispersion of various polymers, etc. in the form of a mist from the supply pipe 18 using the spray device 19. This is to prevent the mixed organic powder layer 20 from collapsing after stopping. When injecting the temporary coagulant 17, it is desirable to temporarily stop the supply of the organic powder materials 1 and 2. These temporary coagulants may be unnecessary depending on the type of organic powder material.

In addition, since the pressure difference between the inside and outside of the molding machine is large, filter 1
2 is preferably made of a highly rigid stainless steel sintered body or supported by a highly rigid filter case.

Based on the above principles, the organic powder material 1 and the organic powder material 2 used can be used regardless of their type, particle size, specific gravity, etc.
It is extremely easy to obtain a molded product in which the amount of ingredients is arbitrarily changed. In some cases, the molded product can be used as is, but in many cases, it can be used as an optical element with a refractive index distribution in the radial direction by further solidifying and making it transparent according to conventional methods. Become.

The above is the principle of the present invention, but in the present invention, two or more types of organic powder materials are used according to the above principle,
Any different types of organic particles can be used as long as they are particles that can be deposited by a filter before solidification, can be finally solidified, and can be made transparent in some cases.

A typical example is a conventionally known polymer that can be used as an optical element, such as trifluoroethyl (meth)acrylate (in this specification, (meth)acrylate is meant to include both acrylate and methacrylate). (same as manufactured), trifluoroisopropyl (meth)acrylate, 2-methoxyethyl (meth)
Acrylate, butyl (meth)acrylate, methyl (
meth)acrylate, cyclohexyl-α-bromoacrylate, P-cyclohexylphenyl (meth)acrylate, O-glolobenzyl (meth)acrylate, β
- Homopolymers made of (meth)acrylate monomers such as naphthyl (meth)acrylate, or (meth)acrylate polymers such as copolymers of these monomers with each other or with other vinyl monomers: vinylhexyl ether, propionic vinyl, 4-methyl - Homopolymers consisting of vinyl heptadons such as 1-pentene, vinylidene fluoride, isobutyne, (meth)acrylonitrile, styrene, p-isopropylstyrene, vinylnaphthalene, vinylcarbazole, ethylene, propylene, butadiene, isoprene, and these monomers Vinyl polymers such as copolymers consisting of these monomers and other monomers; Cellulose polymers such as cellulose acetate and nitrocellulose; polytrimethylene glycol carbonate, poly 2; 2-bis(4-oxydiphenyl); Polycarbonate polymers such as propane carbonate; polyester polymers (9) such as polyethylene terephthalate and polybutylene terephthalate; polyamide polymers such as nylon 6, nylon 66, and nylon 612; polyurethane polymers or polymer main components as described above. Blend polymers and the like can be suitably used.

The above-mentioned polymers are particularly preferred examples in the present invention, but in addition to these, cross-linked polymers made by cross-linking the above-mentioned polymers, thermosetting resins such as phenol resins, melamine resins, urea resins, alkyd resins, and thermosetting resins are also available. Fine powder of cured resin can also be used.

Among the various polymers mentioned above and polymers not exemplified, particularly preferred in the present invention are amorphous polymers having high transparency, such as (meth)acrylic polymers, styrene polymers, and polycarbonate polymers.

One of the features of the present invention is that the various polymers described above can be used in any combination regardless of their type. That is, in the conventional method, it was not possible to use monomers that do not have copolymerizability with each other, and it was also impossible to use a vinyl polymer and a condensation type or polyaddition type polymer together, but the method of the present invention Such various restrictions do not exist at all.

The above examples are particularly preferred examples in the present invention, and any other organic materials can of course be used as subcomponents for these organic powders.

For example, if these subcomponents are powders, they can be used as a type of organic powder material mentioned above, and if they are liquids such as aqueous solutions or dispersions, they can be used as a type of temporary coagulant, or they can be used as a type of temporary coagulant. It is also possible to impregnate the molded product afterwards.

The organic powder materials used in the present invention as described above are as follows.

It may be of any particle size or shape, but considering the ease of transport and mixing and the homogeneity of the resulting molded product, the particle size is about 1 to 3004 m, preferably about 1 to 5 Bm. Those having an average particle size are preferred.

The organic powder materials used in the present invention as described above have two different types.
It is necessary to use it as a mixture of more than one kind, and the number of components does not matter as long as there are two or more kinds. For example, if two kinds of components are used and the mixing ratio of both components is changed as explained in the above principle Alternatively, in the case of three components, one of them may be mixed at a constant mixing ratio while the mixing ratio of the other two components may be varied.

In the above principle, one preferred method for mixing the organic powder materials to be used is exemplified, but the present invention is not limited to the above-mentioned method as long as the mixing ratio of two or more organic powder materials changes. do not have.

For example, a method of constantly supplying a certain component A and changing the amount of addition of another component B and another component C while changing the mixing ratio in the resulting mixture can be used at any time. be.

Furthermore, the method of mixing these organic powder materials is not limited to the above-mentioned method, but any method may be used as long as it is possible to mix two or more organic powder materials by freely changing the mixing ratio. . For example, if there are many ingredients to be mixed, you can increase the number of containers and hoppets accordingly, or mix organic powder materials in a certain ratio in advance.
It may be placed in one container and mixed with other organic powder materials in a transport tube. Furthermore, as exemplified above, the containers may be arranged perpendicularly to the transport pipe instead of parallel to the transport pipe, and other methods for transporting organic powder materials include using a screw such as in an extruder. Any method can be used, such as a method in which the organic powder material is transported simultaneously with mixing, a method using air or other carrier gas, a fluidized bed method, etc.

Further, as a method for molding the mixture obtained as described above, one example is shown in FIG. 2 in the explanation of the principle, but the present invention is not limited to such an illustrative method. Alternatively, high pressure can be used, for example, without the illustrated suction pump 16 and by providing a compressor upstream of the transport line. That is, the method of the present invention can employ any molding method that can continuously deposit and mold the mixed organic powder in the radial direction. In addition, by heating the molding machine to an appropriate temperature during or after molding,
It is also possible to increase the strength of the molded product by individually firing the molded product of the mixed organic powder material or by removing the solvent in the temporary coagulant, thereby making subsequent steps easier.

As described above, a molded product in which two or more different organic powder materials exist in layers in the radial direction with varying abundance ratios can be obtained, but the molded product can be used as it is as a material for optical elements. is removed from the molded product and used as is. On the other hand, since organic powder materials are used as materials, in many cases, in order to improve the strength of the molded product,
Furthermore, when transparency is insufficient, it is preferable to perform solidification and transparency treatments to improve the transparency. For example, it is preferable that the molded product is heat-treated 17 at an appropriate temperature of about 80 to 250°C to sinter or fuse the organic powder particles and to make the whole transparent.

According to the present invention as described above, a desired refractive index distribution is achieved despite the drawbacks of the prior art, such as limitations on various materials, limitations on the size of the obtained optical element, expensive equipment, and the need for time. Various problems such as not being able to obtain the desired product and the product being extremely expensive were easily solved.

That is, according to the present invention, the organic powder material used may be any organic material, and there is no need to suspend it in a dispersion medium, and there is no need to remove the medium after shaping. Furthermore, it is clear that the number of components to be mixed is not limited in any way, and it is possible to provide a molded product that changes (regardless of whether it is linear, curved, or stepwise) depending on the mixing ratio of the components.

Therefore, by solidifying and making transparent such a molded product as necessary, the refraction in the radial direction can be increased to a sufficient degree.
An organic optical element having i can be provided at low cost by fL in a cylinder. And 1.4: The organic optical element obtained by the invention is useful for various optical applications such as optical fiber materials, optical fibers, lenses, etc.;

Next, examples will be given to further concretely put the present invention to practical use. In addition, in the text, the part or % is 'fK by ノ (quasi).

Example 1 The raw materials are powders of polyvinylidene chloride and polyvinylidene fluoride. According to the method described above, polyvinylidene fluoride powder is placed in one container and a powder mixture of polyvinylidene fluoride and polyvinylidene chloride (mixing ratio 1:2) is placed in the other. While flowing the carrier gas through the transport pipe, turn the blower fan and mixing fan, and operate the bovent provided in the container. Polyvinylidene fluoride powder and a powder mixture of polyvinylidene fluoride and polyvinylidene chloride ratio 1:2) respectively into a transport tube.

At this time, the control is performed. The total discharge amount of the two containers is kept constant, and only polyvinylidene fluoride powder is discharged at first. After a while, a mixed powder of polyvinylidene fluoride and polyvinylidene chloride is released. The amounts released from the two containers are gradually changed so that only the mixed powder of polyvinylidene fluoride and polyvinylidene chloride is released at the end of molding. During this time, the blower fan and mixing fan are operated and the former is rotated.

Then, use a suction pump to reduce the pressure outside the molding machine. Finally, a temporary coagulant is ejected to complete the molding.

In this way, a disc-shaped molded product is obtained. This means that the abundance ratio of polyvinylidene fluoride increases successively toward the outer circumference, and the abundance ratio of polyvinylidene n-chloride increases successively toward the center.

The abundance ratio of polyvinylidene chloride is from 0 to 67ta6 from the outer periphery toward the inside.

This molded product was fused in a heating furnace according to the heating program shown below while performing a degassing operation using a vacuum pump to obtain an optical element of the present invention (71).

(]) The molded body is placed in a furnace, degassed using a vacuum pump, and held for 30 minutes.

(2) Raise the temperature to 250°C I7 and hold for 2 hours in a degassed state.

(3) Incubate at 265°C under a pressure of 30 kg/cm'.
- Warm and keep degassed for 3 hours.

(4) Allow to cool naturally.

(5) Return to normal pressure.

When the refractive index distribution of the organic optical palm r of the present invention, which was smoothed in the above steps, was determined, it was found that the /:ii fold in the center is a disc-shaped optical element that becomes smaller toward the outside. ,
This is useful as an optical element.

Example 2 I! (Ne-1 is powder of polystyrene and poly-tert-butylmethacrylate 1. In one container of the apparatus shown in FIG. 1, a 1:1 mixture of polystyrene and poly-tert-butyl methacrylate-1 (A ) on the other hand, and l of polystyrene and polytert-butyl methacrylate on the other hand:
4. Add powder mixture (B). While the carrier gas is flowing through the transport pipe, a blower fan and a mixing fan are turned, a poppet provided in the container is operated, and A and B are discharged into the transport pipe, respectively.

At this time, the poppet is controlled. The total amount of discharge from the two containers is kept constant, and only A is discharged at first. After a while, B is released. The amounts released from the two containers are gradually changed, and only B is released at the end of molding.

During this time, the blower fan and mixing fan are operated and the former is rotated. Then, a suction pump is used to reduce the pressure outside the molding machine, and finally, a temporary coagulant is jetted out to complete the molding.

In this way, a disc-shaped molded product is obtained. This is because polystyrene has a higher abundance ratio toward the outer circumference, and polytetra has a higher abundance ratio toward the center.
The abundance ratio of rt-butyl methacrylate is excellent.

The abundance ratio of polystyrene is 50% from the outer periphery to the inner part.
% to ~20%.

This molded product was fused while being compressed in a desired heating furnace using the heating program shown below to obtain an optical element of the present invention.

(1) The molded body is placed in a furnace in a wet state, degassed using a vacuum pump, and held for 30 minutes.

(2) 50'C! The temperature was raised to 150°C and kept in a degassed state for 1 hour.

(3) The temperature was raised to 100° C. under a pressure of 30 kg/crn' and maintained in a degassed state for 2 hours.

(4) Allow to cool naturally.

(5) Return to normal pressure.

When we measured the refractive index distribution of the organic optical element of the present invention obtained through the above steps, we found that it was a disc-shaped optical element with a large refractive index of 1.53 near the outer periphery and a small refractive index of 1.49 near the center. This is useful as an optical element.

Example 3 Raw materials were butyl acrylate-methyl methacrylate 1:
1 copolymer (A) and polyβ-naphthyl methacrylate (B). In the apparatus of FIG. 1, A is placed in one container and B is placed in the other.

Thereafter, in the same manner as in Example 2, a disk-shaped molded product is obtained in which B is 100% near the outer periphery and A and B are present in an abundance ratio of about 50% near the center.

This molded product was compressed and fused in a desired heating furnace using the heating program shown below to obtain an optical element of the present invention.

(1) Place the compact into a furnace in a horizontal state, degas it using a vacuum pump, and hold for 30 minutes.

(2) Raise the temperature to 50'C and hold for 1 hour in a degassed state.

(3) Raise the temperature to 80°C under a pressure of 30 kg/cm' and keep it in a degassed state for 2 hours.

(4) Allow to cool naturally.

(5) Return to normal pressure.

When we measured the refractive index distribution of the organic optical element of the present invention obtained through the above steps, we found that it was a disc-shaped optical element with a large refractive index of 1.63 near the outer periphery and a small refractive index of 1.48 near the center. This is useful as an optical element.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining the method of the present invention. 1: Material ・ 2; Material 3.4; Container 5.6; Poppet 7; Transport pipe
8; Blowing fan 9; Mixing fan IO: Condition of materials 1 and 2 11: Molding'A 12. Filter 13, mechanical seal 14, bearing (hair ring) 15, exhaust port 16. Suction pump 17: Temporary coagulant 18; Supply path 19; Ejection device 20; Molded product (deposited layer) Patent applicant Canon Co., Ltd. agent Patent attorney Notice 1) Yang Hiro・'-1': ! ′
l −

Claims (1)

[Claims] (1) A powder mixture using two or more organic powder materials with varying mixing ratios is supplied to a molding machine to form a molded product with a varying mixing ratio in the radial direction, and solidified as necessary. and a method for manufacturing an optical element characterized by making it transparent.