JPH0614126B2 - Method for manufacturing synthetic resin optical transmitter - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a synthetic resin optical transmission medium having a refractive index distribution that changes with the distance from the central axis.

[Technical background of the invention]

The transparent rod whose refractive index distribution is represented by the following formula (1) exhibits a convex lens action, and the light flux traveling in the transparent rod is meandering along the central axis. The period L is expressed by the following equation (2). Here, no is a refractive index on the central axis, n (r) is a refractive index at a point r from the central axis, and A is a positive constant (refractive index distribution constant).

When the refractive index distribution is represented by the following equation (3), it exhibits a concave lens action. Where B is a positive constant (refractive index distribution constant)
Is.

n (r) ＝ no (1 + 1 / 2Br ² ) (3) When molding the above-mentioned organic base material, first, the monomer Ma which forms the reticulated polymer Pa having the refractive index Na is prepolymerized and plastic flow In the general formula D = Kα ⁿ (4) (where D is the shear rate, α is the shear stress, K is the reciprocal of the plastic viscosity, and n is a constant), the value of n at 20 ° C. is 1. A viscous fluid exhibiting a plastic flow of 10 or more (hereinafter referred to as a prepolymer fluid) is obtained.
Then, this prepolymer fluid is put into an extrusion device, a constant voltage is applied to a piston moving motor of an extrusion device to continuously extrude the prepolymer fluid, and the prepolymer fluid is supplied to a molding device and heated while advancing through a passage in the molding device. The organic base material is obtained by polymerizing.

Monomer Mb forming a polymer having a refractive index different from Ma in this organic base material, and after being polymerized after being diffused in the liquid phase or the gas phase from the surface of the organic base material or simultaneously with the diffusion, the refractive index It is possible to manufacture a synthetic resin light transmission body in which the value changes continuously from the surface to the inside.

The method for continuously producing a synthetic resin optical transmission body as described above is described in Japanese Patent Application Nos. 58-120625 and 58-12062.
6, the Japanese Patent Application No. 58-120627 proposes the present inventors.
However, this method has the following problems. That is, although the extrusion device is composed of a cylinder and a piston, it is impossible to reduce the pitch error of the feed screw and the speed error of the motor to zero, and there is a limit to move the piston at a constant speed.

Further, there is a limit to the accuracy of the inner diameter of the cylinder, and it is expected that there will be variations.

Therefore, the volume velocity of the prepolymer fluid extruded from the extruder is unlikely to be constant.

Furthermore, since this prepolymer fluid is heated and polymerized to form an organic matrix, a volume change occurs and the rate of change is not always constant.

For this reason, the stability of the volume velocity of the organic base material is further reduced. Since the organic base material is pulled at a constant speed, if the volume speed of the organic base material changes with time,
The diameter of the organic base material also changes.

Further, when the monomer Mb forming a polymer having a refractive index different from that of the Ma polymer is diffused into the base material while the diameter of the organic base material is changed, the refractive index distribution may be changed. become.

From the above, in order to continuously manufacture a synthetic resin optical transmission body with constant quality, first, in order to stabilize the diameter of the organic base material,
Have to control.

[Purpose of occurrence]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for continuously producing the above synthetic resin optical transmission body with a stable wire diameter by eliminating the above-mentioned drawbacks of the prior art.

[Outline of Invention]

The method of the present invention to achieve the above-mentioned object, the pre-polymer fluid is pressure-fed to the molding means, the shape is maintained, and the organic base material in a state in which the additive can be diffused therein is continuously formed from the molding means. Extruding, continuously passing through the diffusion means and heating means to the continuously extruded organic base material, at this time, while the additive is diffused in the organic base material by the diffusion means, by the heating means In the method for producing a synthetic resin optical transmission body, in which the distribution of the additive in the organic base material is fixed by heating the organic base material, the diameter of the organic base material continuously extruded from the molding means is changed. By measuring in the vicinity of the outlet of the molding means and adjusting the amount of the propolymer fed to the molding means based on the measured value,
The gist is to control the diameter of the organic base material.

The present invention also provides a suitable apparatus for carrying out the above method,
Extruder for sending prepolymer fluid to forming means and extruding the formed base material, and extruding device for forming prepolymer fluid supplied from the extruding equipment and extruding base material, and formed by forming equipment Provided is an apparatus for manufacturing a synthetic resin optical transmission body, which comprises a base material diameter measuring device for measuring a diameter of a base material and a measuring device for controlling a prepolymer fluid discharge amount of the extrusion device according to a diameter measurement signal.

〔Example〕

An embodiment of a method for manufacturing a synthetic resin optical transmission body according to the present invention will be described below with reference to the drawings.

In Fig. 1, a cylinder (1) cooled by cooling water contains a prepolymer fluid (30) used as a raw material for a synthetic resin optical transmission medium, and a piston (2) supplies a supply pipe. The above prepolymer fluid (3
0) can be pumped. Further, as shown in FIG. 2, this piston (2) is moved by a pushing motor (4) via a feed screw (21). Next, a through hole (3) having a diameter slightly larger than the outer diameter of the above-mentioned supply pipe (9) is formed at the center of the forming tool (12) as a forming means composed of a brass cylinder. Through hole
Further, a molded tube (13) made of a polytetrafluoroethylene tube having the same diameter as the through hole (3) is attached to the inside of (3). The prepolymer fluid (30) extruded from the supply pipe (9) passes through the polytetrafluoroethylene tube (13). Further, a jacket pipe (11) for passing warm water having a relatively high temperature and a jacket pipe (10) for passing warm water having a relatively low temperature are provided at the above and lower portions of the molding tool (12), respectively. There is a temperature gradient such that the temperature gradually increases from the lower part to the upper part of the ingredient (12).

Above the molding tool (12), a diffusion pipe (18) as a diffusion means.
The columnar organic base material (21) molded by the molding tool (12) is diffused in the diffusion tube (18) in a predetermined manner.

A circular tube (19) having transparent glass windows (14) and (15) for measuring the wire diameter of the organic base material is attached between the diffusion tube (18) and the molding tool (12). It's sandwiched.
The two windows (14) and (15) are mounted in parallel with each other with the organic base material (21) interposed therebetween.

A laser emitting part (7) and a laser receiving part (6) are installed on both sides of the circular tube (19) with a window, and the laser light (8) is transmitted through the window (14) by the sound or the organic base material (21). ) Is designed to scan in the direction across.

The light ray (8) transmitted through the base material (21) is detected by the light receiving section (6),
The diameter is calculated based on the time during which the amount of received light during scanning is reduced, that is, the scanning time through which the base material (21) is transmitted.

The laser light receiving unit (6) is connected to the wire diameter controller (5), and the deviation between the measured value and the set value of the wire diameter of the organic base material is sent to the wire diameter controller (5). Then, a control signal is calculated based on this input signal and is fed back to the drive voltage of the extrusion motor (4), and the extrusion speed of the piston (2) is measured so as to match the wire diameter of the organic base material with the set value.

The base material (21) continuously extruded from the molding tool (12) by the pressing force of the piston (2) has a shape-retaining property, and the additive can be diffused inside.

The base material (21) exiting the molding tool (12) then enters the diffusion tube (18). In this diffusion tube (18), the monomer that constitutes the base material
Monomers that form polymers with different refractive indices from Ma polymers
Mb is supplied in vapor or liquid state. This monomer Mb diffuses from the surface of the base material (21) to the inside, and a distribution is formed in the base material in which the concentration of Mb gradually decreases from the surface toward the center.

The base material (21) exiting the diffusion pipe (18) then enters the heating pipe (20) where it is heated to cause polymerization to proceed and the distribution of the monomer Mb diffused in the base material is fixed. .

The base material (21) whose polymerization is almost completed while passing through the heating pipe (20) is drawn out by the drawing rollers (16) and (17),
It is cut into a predetermined length by a cutting device (not shown).

The cut base material having a refractive index distribution inside is used for a lens, an optical transmission fiber, etc. by polishing both ends, or it is further heated and stretched to reduce the diameter and then subjected to the above treatment to produce a lens, an optical transmission fiber, etc. used.

As the monomer Ma to be a raw material of the transparent gel body as the organic matrix in the above-mentioned examples, a monomer having two or more kinds of allyl group, acrylic acid group, methacrylic acid group or vinyl group is used. The body can be used. Next, specific examples of the monomer Ma will be given.

(1), allyl compounds diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl esters such as diethylene glycol bisallyl carbonate: triallyl trimellitate,
Triallyl esters such as triallyl phosphate and triallyl phosphite: unsaturated acid allyl esters such as allyl methacrylate and allyl acrylate.

(2), compounds represented by R ₁ -R ₂ -R _{3 wherein} R ₁ and R ₃ are both vinyl group, acryl group, vinyl ester group or methacryl group: _one of R ₁ and R ₃ is A compound which is any one of four groups of a vinyl group, an acrylic group, a methacrylic group and a vinyl ester group, and the other one of the remaining three groups. Here, R ₂ can be selected from the divalent groups shown below.

(3), a mixture of the above (1) and (2) monomers, or at least one of five types of monovinyl compounds, vinyl esters, acrylic acid esters and methacrylic acid esters
A mixture of the seed and the monomer (or mixture thereof) of (1) or (2) above.

Further, examples of the monomer Mb include the following.

However, in the formula, X is a hydrogen atom or a methyl group, and Y is _{-CH = CH 2, - (CH} 2) lH (l = 1~8), i- propyl, i- butyl, s- butyl, t- butyl group, as well as Group selected from the group consisting of _{or, - {CF 2) a -F} (a = 1
~ 6), -CH ₂ (CF ₂ ) _b H b = 1 to 8), -CH ₂ CH ₂ O ・ CH ₂ CF ₃ ,-(CH ₂ CH ₂ O) _c CF ₂ CF ₂ H (c = 1 _{~4), -CH 2 CH 2 O} · CH 2 (CF 2) a F (a = 1~6), -CH 2 (CF 2) d O (CF 2) l F (d = 1~2, l = 1 to 4) and −Sl (OC ₂
H ₅ ) ₃ represents a group selected from the group consisting of.

However, in the formula, R ₄ is-(CH ₂ ) _f -CH ₃ (f = 0 to 2),-(CH ₂ ) _g H
(g = 1-3), as well as Represents a group selected from the group consisting of

A mixture of the monomers (6), (4) and (5).

Any of the above (1) to (3) as the monomer Ma and any of (4) and (6) as the monomer Mb can be combined.

Further, in order to adjust the gelling state of the transparent gel object,
(3) A method of adding a monomer having one unsaturated group to the crosslinkable monomer Ma and a method of adding a chain transfer agent such as CB _r4 , CCl ₄ , and mercaptans, or A method of using both is effective.

[Test example]

Next, an example of controlling the organic base material by the method of controlling the wire diameter of the organic base material in the production of the synthetic resin optical transmission body according to the present invention will be described.

Diethylene glycol bisallyl carbonate (CR-3 in which 3.0% by weight of benzoyl peroxide (BPO) was dissolved
9) was heated at 75 ° C. for 65 minutes and prepolymerized to prepare a prepolymer fluid. This prepolymer fluid has a viscosity of about 1000 cps (20 ° C) and n
Is a viscous fluid with a value of n = 1.20. This prepolymer fluid was placed in the cylinder (1) and placed in a polytetrafluoroethylene tube (13) having a diameter of 4 mm and a length of 200 mm which penetrated the molding tool (3) at 6.3 × 10 ^-2 ml / min. It was continuously fed at a constant flow rate.

78 ° C for the upper jacket pipe (11) of the molding tool (12)
Warm water of 58 ° C. flows into the lower jacket pipe (10), and a temperature gradient is gradually increased from the lower part to the upper part of the molding tool (12). While passing through the Teflon tube (13) for 40 minutes, the prepolymer fluid was gelled and formed into an organic matrix with a diameter of about 4 mm.

This organic matrix is composed of 25% by weight of acetone insoluble component (reticulated polymer), 5% by weight of acetone soluble and methanol insoluble component (linear polymer), acetone soluble and methanol soluble component (monomer).・ Quantity) 70% by weight.

The organic base material was pulled up into the diffusion tube (18) by the pulling up rollers (16) and (17) at a constant rate of 0.52 cm / min.

When a He-Ne laser with an output of 1 mW is scanned by a sound emission from the laser emission part through the windows (14) and (15) of the circular tube (19) through this organic base material, the change in the amount of received light can be detected by the amount of received light. The wire diameter is measured.

From the wire diameter measuring device, a deviation output is generated in proportion to the deviation between the measured wire diameter of the organic base material and the set value. This deviation output is sent to the wire diameter controller (5), PID control calculation is performed, and the drive voltage sent to the extrusion motor (4) is determined. In this case, the P, I, and D coefficients were 30%, 7 minutes, and 0.1 minutes.

By performing the above feedback control operation, the deviation of the wire diameter of the organic base material was improved from ± 60 μm to ± 5 μm with respect to the measured value of 4.00 mm. Further, the polymerization was completed, and the deviation of the diameter of the synthetic resin optical transmission body that came out from the pull-up rollers (16) and (17) as a product and was improved from ± 80 μm to ± 15 μm.

〔The invention's effect〕

As described above, according to the method for controlling the wire diameter of the organic base material in the production of the synthetic resin optical transmission body according to the present invention, it is possible to continuously produce the organic base material having a regular wire diameter, and thus the diameter. Further, it is possible to stably and continuously manufacture a synthetic resin transmission body having uniform optical performance.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of an apparatus for carrying out the present invention,
FIG. 2 is an enlarged view of a main part of the apparatus shown in FIG. In the reference numerals used in the drawings, (1) ... cylinder, (2) ... piston (3) ... through hole, (4) ... extrusion motor (5) ... wire diameter controller, (6) ... Laser receiver (7) Laser emitter (8) Laser light (9) Supply tube (10), (11) Hot water jacket tube (12) Molding tool (13 ) …… Molded tube (14) …… Wire diameter measurement window, (15) …… Wire diameter measurement window (16) …… Pulling motor, (17) …… Pulling motor (18) …… Diffusion tube , (19) …… Circular tube with window (20) …… Heat treatment tube, (21) …… Feed screw.

Claims (1)

[Claims] 1. A prepolymer fluid is pressure-fed to a molding means to continuously extrude from the molding means an organic base material which is in a state of retaining a shape and allowing an additive to diffuse therein. The organic base material is continuously passed through a diffusing means and a heating means, and at this time, the additive is diffused in the organic base material by the diffusing means, and the organic base material is heated by the heating means. In the method for producing a synthetic resin optical transmission medium in which the distribution of the additive in the organic base material is fixed, the diameter of the organic base material continuously extruded from the forming means is measured near the outlet of the forming means. ,
A method for producing a synthetic resin light transmission body, characterized in that the diameter of the organic base material is controlled by adjusting the amount of the propolymer fed to the molding means based on the measured value.