JPH0634804A - Gradient index type plastic optical transmitter - Google Patents

Abstract

PURPOSE:To continuously and efficiently manufacture the optical transmitter which has a desired refractive index distribution by forming the transmitter in a rectangular parallelepiped shape and approximating the refractive index distribution to a specific refractive index curve from the center axis layer of the optical transmitter toward both its thickness-directional surfaces. CONSTITUTION:This optical transmitter is a gradient index type plastic optical transmitter which converges light and is in the rectangular parallelepiped shape and also a gradient index type plastic optical transmitter which has a refractive index distribution approximated to the refractive index curve prescribed by an equation from the center axis layer to both its surfaces in the thickness direction of the optical transmitter. In the equation, n0 is the refractive index of the center axis part of the gradient index type optical transmitter and n(a) is the refractive index at a position part at a distance (a) from the center axis of the gradient index type optical transmitter toward the flanks. Further, (g) is the refractive index distribution constant of the gradient index type optical transmitter and (a) is the distance from the center axis of the gradient index type optical transmitter toward the flanks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a light converging lens and an optical IC.
The present invention relates to a gradient index plastic optical transmission body used in industry.

[0002]

2. Description of the Related Art Among cylindrical optical transmitters having a continuous refractive index distribution, glass-made optical transmitters have been proposed in Japanese Examined Patent Publication No. 47-816. Their low utility and high cost greatly limit their fields of use. For such a glass optical transmitter,
Several methods have been proposed for producing a plastic optical transmission body having a continuous refractive index distribution. For example,
(1) A synthetic resin body made of an ionic cross-linked polymer, in which the concentration of metal ions is continuously changed from the center to the surface thereof (Japanese Patent Publication No. 47-26913),
(2) A synthetic resin body produced from a mixture of two or more kinds of transparent polymers having different refractive indexes is treated with a specific solvent to partially dissolve and remove at least one of the constituent components of the synthetic resin body. Manufactured by (Japanese Patent Publication No. 47-28
No. 059), (3) Two kinds of monomers having different refractive indexes were produced by devising a polymerization method so that a refractive index distribution could be continuously formed from the surface to the inside (Japanese Patent Publication No. 54-3).
No. 0301), (4) A monomer having a refractive index lower than that of the polymer is diffused from the surface of the crosslinked polymer, and the monomer is arranged such that the content of the monomer continuously changes from the surface to the inside and then polymerized. With a refractive index distribution (Japanese Patent Publication Sho 5
No. 2-5857, Japanese Examined Patent Publication No. 56-37521), (5) A low molecular weight compound having a lower refractive index than the polymer is diffused from the surface of the reactive polymer and reacted to continuously form the inside from the surface. Which has a refractive index distribution (Japanese Patent Publication No. 57-29682), and (6) two or more unpolymerized resin compositions having different refractive indices are concentrically compound-spun and then subjected to diffusion treatment to obtain a refractive index. Polymerization and curing after distribution (WO91 / 05274, WO91 / 0527
5) etc.

[0003]

The gradient index optical transmission members produced by the above-mentioned method are all columnar materials, and several tens or more cylindrical optical transmission members are arranged in parallel in a line shape, The two substrates are bonded and sandwiched between them to assemble the image reading sensor, etc., but a special jig must be used to arrange many cylindrical optical transmission elements in parallel, which speeds up the assembly. Is hindering

[0004]

Therefore, the inventors of the present invention have heretofore developed the arrangement of a large number of rod-shaped optical transmitters when assembling an image reading array using a gradient index rod-shaped optical transmitter element. The present invention has been completed as a result of studies for the purpose of obtaining an optical transmission body that is significantly improved over the conventional one, and the gist of the present invention is that it has a light converging property and is a rectangular parallelepiped. It is a gradient index plastic light transmission body having a shape, and the thickness direction of the light transmission body extends from the central axis layer toward both side surfaces [Equation 1].

It is a graded-index plastic optical transmission body having a graded index distribution that is approximately similar to the graded index curve defined by the equation (1).

A preferred method for producing the rectangular parallelepiped gradient index plastic optical transmission article of the present invention will be described. First,
Transparent polymer (I) having appropriate refractive index and the polymer (I)
And a monomer (II) capable of forming a transparent polymer having an appropriate refractive index, and m (an integer of m ≧ 2) of the polymer composition. When the refractive index of the cured product of the combined composition is n ₁ , n ₂ , n ₃ ...... n _m , n ₁ > n ₂ > n ₃ >
......> providing a polymer composition satisfying the n _m the relationship, n ₁
The innermost layer is a polymer having a refractive index of, each layer is laminated and discharged so that the refractive index of the layers on both sides of the layer decreases symmetrically, and monomer diffusion treatment is performed between the layers, from the rectangular parallelepiped central axis layer, The refractive index distribution type optical transmission article which is the object of the present invention can be obtained by making the refractive index distribution close to the quadratic curve distribution toward both outer surfaces thereof and curing the distribution.

The polymer (I) having good transparency used for carrying out the present invention constitutes the substrate of the optical transmission body of the present invention, and a plurality of resin compositions containing the polymer are subjected to a composite extrusion molding method. As a result of ensuring extrusion stability when laminating into a prismatic shape, and a component necessary for keeping the thickness of each layer constant, for example, a homopolymer of methyl methacrylate or methyl methacrylate and other comonomers. Copolymer, polystyrene, styrene copolymer, polycarbonate,
Examples thereof include poly-4-methylpentene-1, fluorinated alkyl methacrylate polymer and the like. Monomers copolymerizable with these monomers include ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2- Hydroxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2- (n-butoxy) ethyl (meth) acrylate, glycidyl (meth) acrylate,
2-Methylglycidyl (meth) acrylate, phenyl (meth) acrylate, monofunctional methacrylates such as benzyl (meth) acrylate, acrylates, 2,2,
2-trifluoroethyl (meth) acrylate, 2,2,3,3-
Tetrafluoropropyl (meth) acrylate, 2,2,3,
3,3-pentafluoropropyl (meth) acrylate, 2,
2,3,4,4,4-hexafluorobutyl (meth) acrylate, 2,2,3,3,4,4,5,5-octafluoropentyl (meth)
Examples thereof include fluorinated alkyl (meth) acrylates such as acrylate, acrylic acid, methacrylic acid, styrene, chlorostyrene and the like.

Among these transparent polymers (I), polymethylmethacrylate and methylmethacrylate-based polymers are mixed with these polymers to form a phase with a monomer used to change the refractive index of the resin composition. It has the advantages of good solubility and good transparency of the cured product obtained by curing these resin compositions.

As the monomer capable of dissolving the polymer (I) having good transparency, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl ( (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2- (n-butoxy) ethyl (meth) acrylate, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, Monofunctional methacrylates or acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate, Fluorinated alkyl acrylates such as 2,2,2-trifluoroethyl acrylate, styrene, chlorostyrene, methacrylic acid, acrylic acid, etc. Other alkylene glycol (Meth) acrylate, trimethylolpropane di or tri (meth) acrylate, pentaerythritol di-, tri- or tetra (meth) acrylate, diglycerol tetra (meth)
Acrylate, dipentaerythritol hexa (meth)
In addition to acrylates, polyfunctional methacrylates such as diethylene glycol bisallyl carbonate and fluorinated alkylene glycol poly (meth) acrylates,
Examples thereof include acrylates.

In the present invention, a polymer (I) having good transparency and a monomer (I) which can dissolve the polymer to form a polymer having good transparency
In order to form a mixture of the mixture with I) into a rectangular parallelepiped, it is preferable to use a rectangular parallelepiped molding apparatus as shown in FIG. 1, for example. In FIG. 1, 1 is a composite nozzle for forming a composite laminated rectangular parallelepiped, 2 is an extruded uncured multilayer laminated rectangular parallelepiped, and 3 is a monomer which exists in each layer constituting the rectangular parallelepiped and is mutually diffused between adjacent layers. To provide a continuous refractive index distribution between the respective layers, 4 is a hardening treatment part for hardening the uncured formed multi-layered rectangular parallelepiped, 5 is a take-up roller, and 6 is made according to the present invention. It is a graded index plastic light transmitter.

When the uncured monomer present in the resin composition is to be cured, a heat curing catalyst and / or a photocuring catalyst is interposed in the mixture, and heat treatment or light irradiation treatment is carried out. Is good. As the thermosetting catalyst, a generally used peroxide catalyst can be used, and as the photocuring catalyst, benzophenone, benzoin alkyl ether, 4′-isopropyl-2-hydroxy-2-methyl-propiophenone, 1- Hydroxycyclohexyl phenyl ketone, benzyl methyl ketal, 2,
2-diethoxyacetophenone, chlorothioxanthone,
Thioxanthone compounds, Benzophenone compounds, 4-
Examples thereof include ethyl dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, N-methyldiethanolamine and triethylamine.

The light source used for photopolymerization is 150 to 600 nm
It is possible to use a carbon arc lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a low-pressure mercury lamp, a chemical lamp, a xenon lamp, a laser beam, etc.

[0012]

According to the present invention, a rectangular parallelepiped gradient index plastic optical transmission medium can be continuously and efficiently manufactured, and its industrial merit is extremely large. Further, according to the present invention, in the gradient index plastic optical transmission medium, by changing the refractive index of the component of each layer and by changing the thickness of each layer, it is very difficult with the conventionally developed technique. A refractive index distribution type optical transmission body having a refractive index distribution of

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

[0014]

Example 1 Polymethylmethacrylate ([η] = 0.5
6, measured in MEK solvent at 25 ° C) 50 parts by weight, benzyl methacrylate 35 parts by weight, methyl methacrylate 15 parts by weight,
Heat-kneaded 0.2 parts by weight of 1-hydroxycyclohexyl phenyl ketone and 0.1 parts by weight of hydroquinone at 70 ° C. was used as a stock solution for the first layer (central axis layer), and polymethylmethacrylate ([η] = 0.43, in MEK solvent) 50 parts by weight, 50 parts by weight of methyl methacrylate, 0.2 parts by weight of 1-hydroxycyclohexyl phenyl ketone, and 0.1 parts by weight of hydroquinone were heated and kneaded at 70 ° C. for the second layer (both sides of the first layer). ), Polymethylmethacrylate ([η] = 0.43, measured in MEK solvent at 25 ℃)
48 parts by weight, 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate 37 parts by weight, methyl methacrylate 15 parts by weight, 1-hydroxycyclohexyl phenyl ketone 0.2 parts by weight, hydroquinone 0.1 parts by weight 70 parts by weight What was heated and kneaded at 0 ° C. was used as a stock solution of the third layer (layers on both side surfaces of the second layer).
The undiluted solution of each of these layers was formed using a rectangular parallelepiped forming nozzle (3rd
Layer): (Second Layer): (First Layer): (Second Layer): (Third Layer)
(Layer) = 1: 2: 3: 2: 1 was extruded at a discharge ratio of 1: 2, and laminated and shaped so as to be bilaterally symmetrical. After that, it passes through the mutual diffusion treatment part (total length 50 cm, 25 ° C), the monomers existing in each layer are mutually diffused between layers, and then it passes through the curing treatment part, and the rectangular parallelepiped plastic with a thickness of 2.4 mm. Got When the refractive index in the thickness direction of the plastic was measured by an interphaco interference microscope (Carl Zeiss, Germany), the refractive index of the central axis layer part was 1.513, and the refractive index of both side surface layer parts was 1.473. The refractive index continuously decreased from the axial layer portion to both side surface portions, and the value of the refractive index distribution constant g obtained by the least square method was 0.192 (mm ^-1 ).

[0015]

[Embodiment 2] The refractive index in the thickness direction of a rectangular parallelepiped plastic having a thickness of 2.4 mm obtained in exactly the same manner as in Embodiment 1 except that the total length of the interdiffusion treated portion is changed to 100 cm. The layer portion had 1.508 and the side surface portions had 1.479, and the value of the refractive index distribution constant g determined by the least square method was 0.163 (mm ^-1 ). Thus, the refractive index distribution could be easily changed by changing the mutual diffusion treatment time.

[0016]

[Third Embodiment] A thickness of 2.4 m prepared in exactly the same manner as in the first embodiment, except that the temperature of the mutual diffusion treatment section is changed to 30 ° C.
The refractive index in the thickness direction of the rectangular parallelepiped plastic of m is
The value of the refractive index distribution constant g obtained by the least squares method is 1.502 for the central axis layer and 1.485 for both side surfaces.
It became 0.125 (mm ^-1 ). Thus, the refractive index distribution could be easily changed by changing the temperature of the mutual diffusion processing part.

[0017]

Fourth Embodiment In the first embodiment, the discharge ratio of the undiluted solution from the rectangular parallelepiped forming nozzle is (third layer) :( second layer) :( first layer).
(Layer): (second layer): (third layer) = 1: 2: 4: 2: 1 except that the thickness of 2.4 mm rectangular parallelepiped plastic obtained in exactly the same manner, The central axis layer portion was 1.515 and both side surface portions were 1.481, and the value of the refractive index distribution constant g obtained by the least squares method was 0.177 (mm ^-1 ).
By changing the discharge ratio in this way, the refractive index distribution could be easily changed.

[0018]

[Example 5] The refractive index in the thickness direction of a rectangular parallelepiped plastic obtained by shaping a rectangular parallelepiped plastic to a thickness of 3.6 mm in exactly the same manner as in Example 1 except that the discharge speed of the stock solution is changed. , The central axis layer part is 1.515,
Both side surface portions were 1.469, and the value of the refractive index distribution constant g obtained by the least square method was 0.137 (mm ^-1 ). Thus, the refractive index distribution could be easily changed by changing the thickness of the rectangular parallelepiped plastic.

[0019]

Example 6 In Example 1, the stock solution composition of the first layer was changed to polymethylmethacrylate ([η] = 0.56, 25 in MEK solvent).
50 parts by weight, benzyl methacrylate 20 parts by weight, methyl methacrylate 30 parts by weight, 1-hydroxycyclohexyl phenyl ketone 0.2 parts by weight, hydroquinone
0.1 parts by weight of the composition, and the undiluted composition of the third layer is 48 parts by weight of polymethylmethacrylate ([η] = 0.43, measured at 25 ° C in MEK solvent), 15 parts by weight of methylmethacrylate, 2,2,
37 parts by weight of 3,3-tetrafluoropropyl methacrylate,
The refractive index in the thickness direction of a 2.4 mm-thick rectangular parallelepiped plastic obtained in exactly the same manner as in Example 1 except that the composition was changed to 0.2 part by weight of 1-hydroxycyclohexyl phenyl ketone and 0.1 part by weight of hydroquinone was obtained. Was 1.499, both side surfaces were 1.478, and the value of the refractive index distribution constant g determined by the least square method was 0.139 (mm ^-1 ).

[0020]

[Embodiment 7] The first layer forming undiluted solution used in Example 1 was directly used as the first layer forming undiluted solution, and the first layer used in Example 6 was used.
The layer forming stock solution was used as the second layer forming stock solution, the second layer forming stock solution used in Example 1 was used as the third layer forming stock solution, and the third layer forming stock solution used in Example 6 was used as the second stock forming solution. The four-layer forming stock solution was used, and the third-layer forming stock solution used in Example 1 was used as the fifth-layer forming stock solution. (Fifth layer): (Fourth layer): (Third layer):
(Second layer): (First layer): (Second layer): (Third layer):
(4th layer): (5th layer) = 1: 1: 2: 3: 4: 3:
Example 1 except that layered shaping was performed at a discharge ratio of 2: 1: 1.
The refractive index in the thickness direction of a rectangular parallelepiped plastic having a thickness of 2.4 mm obtained in the same manner as
Both side surface portions were 1.459, and the value of the refractive index distribution constant g obtained by the least squares method was 0.230 (mm ^-1 ).

[0021]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a shaping device that can be usefully used for making a rectangular parallelepiped gradient index optical transmission body of the present invention.

[Explanation of symbols] 1 Nozzle for forming a composite laminated cuboid 2 ………… Extruded uncured multilayer laminated cuboid 3 ………… Mutual diffusion treatment part 4 ………… Curing treatment part 5 …… ...... Take-off roller 6 ………… A rectangular parallelepiped type gradient index plastic optical transmission body of the present invention

Claims (1)

[Claims] 1. A gradient index plastic optical transmission body having a rectangular parallelepiped shape, and [Numerical formula 1] [Numerical formula 1] from both sides of the central axis layer of the optical transmission medium in the thickness direction. A rectangular parallelepiped gradient index plastic optical transmission body having a gradient index distribution approximately similar to the gradient index curve defined in.