JPH07151928A - Plastic optical transmission body - Google Patents

Abstract

PURPOSE:To provide a plastic optical transmission body capable of branching light propagated through the optical transmission body well without the insertion of such an optical system as a mirror. CONSTITUTION:As to this optical transmission body having a core part 1 which is constituted of transparent plastic and transmits the light 5, and having a clad part surrounding the core part 1: a white turbidity part 6 scattering and reflecting the light is provided on the part of the core part 1. Thus, the optical transmission body, a light transmission body, and an illuminator capable of uniformly scattering and reflecting the light in an optional direction can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic optical transmission body utilizing light scattering reflection.

[0002]

2. Description of the Related Art Conventionally, in an optical circuit element, as described in Japanese Patent Laid-Open No. 63-63007, a refractive index difference based on Snell's law is used for controlling transmission of light such as branching and coupling. A method or a method of providing an optical system such as a mirror or a lens in an optical transmission line is known. As disclosed in Japanese Patent Application Laid-Open No. 2-111922, a light guide used for a liquid crystal display or a light guide device for illuminating instrument panels, etc. has a reflector plate with a curved surface or unevenness. It is formed so that reflected light of uniform intensity can be obtained when viewed from the front.

[0003]

In the above-mentioned prior art, when the light is branched in the optical transmission medium, light leakage occurs if the light is branched at an angle less than the critical angle at which the light is not totally reflected. Therefore, the optical transmission line (core) also needs to have a gentle arc shape. In addition, since it is impossible to reflect the light at a right angle or form a small radius of curvature equal to or less than the critical angle, it is unsuitable for producing an optical transmission body having a compact or compact three-dimensional structure.

The method of installing an optical system such as a mirror and a lens in the transmission line has a problem that the number of reflections on the surface increases, so that highly accurate optical polishing is required for the end surface of the optical system and the configuration becomes complicated. there were.

Further, in the light guide portion of a liquid crystal display or the like, the intensity of the reflected light strongly depends on the viewing angle, and it is necessary to increase the intensity of the light source because the reflected light having a uniform intensity cannot be obtained unless it is viewed from the front. There was a problem such as.

An object of the present invention is to solve the above problems.
An object of the present invention is to provide an optical transmission body capable of optical branching at an arbitrary branching angle.

Another object of the present invention is to provide an optical transmission body having a light guide section in which the intensity of reflected light is less dependent on the viewing angle. Other purposes will be apparent from the description below.

[0008]

[Means for Solving the Problems] As a result of studying a method of efficiently scattering and reflecting light in a specific direction even at an angle equal to or less than a critical angle of light, as a result, a plastic polymer was introduced without introducing an optical system such as a mirror. The inventors have arrived at the present invention by finding means capable of scattering and reflecting light in a specific direction only by using the above method. The gist of the present invention is as follows.

(1) An optical transmission body made of transparent plastic, in which a cloudy portion where light is scattered and reflected is provided in a part thereof.

(2) The plastic optical transmission article as described in 1 above, wherein the cloudy portion is provided in a branch portion or a reflecting portion having an angle equal to or less than a critical angle of light.

(3) An optical transmission body having a core part for transmitting light and a clad part surrounding the core part, which is made of transparent plastic, in which a part of the core part scatters and reflects light, and a cloudy part. A plastic optical transmitter equipped with.

(4) An optical transmission body in which optical transmission lines provided in two or more layers of plastic substrates are connected by a plastic optical transmission body having a core and a clad, and light is applied to the connecting portion of the core. A plastic optical transmitter with a cloudy part that is scattered and reflected.

By providing the cloudy portion, it is possible to form a core portion which is reflected at a right angle or has a small radius of curvature equal to or less than the critical angle, and the optical circuit can be downsized or highly integrated by a multilayer structure. Further, it is possible to manufacture a light guide device having a wide viewing angle and capable of obtaining reflected light of uniform intensity. It is suitable for decoration display by mixing a pigment or the like in the cloudy portion to color it.

Known materials can be used as the organic monomer which is a raw material of the plastic optical transmission medium of the present invention. Particularly, a methacrylic acid ester derivative and an acrylic acid ester derivative are preferable. For example, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3,4,4, 5,
5-octafluoropentyl methacrylate, glycidyl methacrylate, ethylene glycol dimethacrylate, hydroxyethyl methacrylate, phenyl methacrylate, stearyl methacrylate, propyl methacrylate, butyl methacrylate, dimethylaminoethyl methacrylate, tridecyl methacrylate and the above acrylic ester, methyl-α- There are fluoro acrylate, trifluoroethyl-α-fluoro acrylate, pentafluoropropyl-α-fluoro acrylate, methyl-α-chloro acrylate and the like.

[0015]

[Function] Even if each of the monomers obtained by homopolymerizing the monomer, which is a component of the copolymer, is transparent, it may become opaque when two or more of them are copolymerized. This is a phenomenon in which each homopolymer undergoes phase separation on the order of wavelength of light and is caused by interface reflection based on the difference in refractive index between the two phases. Therefore, when a monomer having a large difference in refractive index is polymerized so as to have a stepwise composition distribution, a cloudy part is generated in a specific composition range. This cloudy portion has a scattering reflection effect.

Since the interface reflection is almost due to Mie scattering and Rayleigh scattering, the intensity of the reflected light does not have the angle dependence of the incident light as in the case of a normal reflecting plate. It is suitable when a wide viewing angle is a problem. It also enables right-angle branching, which was not possible with conventional optical branching devices.

[0017]

EXAMPLES The present invention will be described in detail based on examples.

Example 1 A white turbid portion is formed using a benzyl methacrylate monomer and a methyl methacrylate monomer. An optical circuit board having a two-layer structure as shown in the schematic perspective view of FIG.
An optical circuit board having a two-layer structure of 10 cm × 15 cm made of an injection-molded substrate 2 (also serving as a clad) of X resin: manufactured by Mitsui Petrochemical Co., Ltd. was prepared. As shown in FIG. 2, a hemispherical acrylic polymer is placed at the intersection of the substrate 2 where the light branching portion of the optical transmission core 1 is to be formed, and a turbid portion is formed using benzyl methacrylate monomer and methyl methacrylate monomer. Then, a 1.5 mm × 1.5 mm core portion was cast-polymerized. Benzoyl peroxide was added in an amount of 0.3% by weight as a polymerization initiator for the above monomers.

After curing, the branching portion 6 becomes a hemispherical cloudy portion, and the incident light 5 is transmitted through the core 1 and is split into four directions of up, down, left and right. As the transmitted light, a red LED with a wavelength of 660 nm was used. The transmitted light emitted from the LED was successfully transmitted to the upper and lower optical circuit boards. The upper optical circuit board has a small light-receiving / emitter-embedding element 3 in the middle thereof.

An optical fiber was connected to the emission end of the optical circuit board via the optical fiber connector 4, and the motor connected via the OE and EO circuits was driven.

Comparative Example 1 An optical circuit board having a two-layer structure similar to that of Example 1 was prepared. However, a hemispherical acrylic polymer was not used in the light branching portion, and a core was formed from a homopolymer of methyl methacrylate monomer. Most of the incident light leaked at the branch, and the system using this circuit board did not work.

Example 2 An optical circuit board made of TPX resin having a single layer structure of 10 cm × 15 cm as shown in the schematic perspective view of FIG. 3 was produced. As shown in Fig. 4, a wedge-shaped acrylic polymer was installed on the bent portion of the optical transmission body core that forms the cloudy portion, and the core 1 of 1.5 mm × 1.5 mm was poured using benzyl methacrylate monomer and methyl methacrylate monomer. Type polymerized. The polymerization initiator benzoyl peroxide was added in an amount of 0.3% by weight.

Light is transmitted through the core 1 and the white turbid portion 6 at the bent portion.
It was possible to drive the motor connected to the OE and EO circuits via the plastic optical fiber as in the first embodiment by transmitting the core 1 which was reflected by and was bent at a substantially right angle.

[Embodiment 3] A planar light guide as shown in the sectional view of FIG. 5 is used, an acrylic polymer plate is installed on the side where the cloudy portion 6 is formed, and benzyl methacrylate monomer and methyl methacrylate monomer are used. And polymerize 1
A planar light guide having a size of cm × 15 cm × 23 cm was produced.
The polymerization initiator was added in an amount of 0.3% by weight of benzoyl peroxide. When a white fluorescent lamp was used as the light source 7 and light was made incident by the reflecting mirror 8, the light emitted surface light with uniform intensity, and uneven light emission due to location was hardly observed.

[Comparative Example 2] A light source built-in light guide similar to that of Example 3 was produced using a mirror. The light guide body had a larger reflected light intensity on the surface closer to the light source part, and it was not possible to obtain a light emitting surface having a uniform light intensity.

[Embodiment 4] A branch portion, a bent portion, and
10 cm with an optical transmission core with three types of curved structure
A × 18 cm optical circuit board was prepared. An acrylic polymer plate was placed on each of the above three types of parts to form a cloudy part, and a core was formed using a benzyl methacrylate monomer and a methyl methacrylate monomer. The size of the cross section of the core 1 is 1.5 mm × 1.5 mm. The polymerization initiator was added in an amount of 0.3% by weight of benzoyl peroxide.

When light emitted from the red LED light source of 660 nm was made incident using a plastic optical fiber, excellent light emission was recognized from the other end face. The light incident side was replaced with the light emitting side, but the light intensity was almost unchanged.

[Embodiment 5] 10 cm × as shown in FIG.
A 25 cm instrument panel display was made. In the bent white turbid part of the optical transmission unit connected to the part you want to color-code the display,
An acrylic polymer chip prepared by adding 0.05% by weight of Rhodamine 6G dye was installed, and benzyl methacrylate and methyl methacrylate monomer were used, and 0.3% by weight of benzoyl peroxide was used as a polymerization initiator.
Add and polymerize. A 1.5V miniature bulb was used as the light source 7. Despite the light source of a miniature electric bulb of only 1.5 V, a good red display with uniform emission intensity was obtained.

[Sixth Embodiment] An outer diameter 20 as shown in FIG.
A rod-shaped lighting device having a size of mm × 50 cm was manufactured.
A mixed monomer of benzyl methacrylate monomer and methyl methacrylate monomer added with 0.3% by weight of benzoyl peroxide as a polymerization initiator was injected into a mold holding an acrylic rod in the central portion to cause polymerization, and the diameter of the rod central portion was about A 5 mm cloudy portion 6 was formed. Sunlight was used as a light source, and sunlight was incident from one rod end surface using a plastic optical fiber bundle (10 pieces) 9. Due to the sunlight, there was no heat generation in the light emitting part, and an illumination device with uniform light emission was obtained.

[0030]

According to the present invention, it is possible to obtain a plastic light transmission body, a light guide body, or a lighting device capable of uniformly scattering and reflecting light in an arbitrary direction.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a two-layer optical circuit board.

FIG. 2 is a schematic perspective view of a branch portion of a two-layer optical circuit board.

FIG. 3 is a schematic perspective view of a one-layer optical circuit board.

FIG. 4 is a schematic cross-sectional view of a bent portion of a one-layer optical circuit board.

FIG. 5 is a cross-sectional view of a light guide with a built-in light source.

FIG. 6 is a cross-sectional view of a characteristic measuring optical circuit board.

FIG. 7 is a plan view of an instrument panel display unit.

FIG. 8 is a schematic perspective view of a rod-shaped lighting device.

[Explanation of symbols]

1 ... Core (optical transmission unit), 2 ... Substrate (also clad), 3 ...
Element with built-in light receiving and emitting parts, 4 ... Optical fiber insertion connector,
5 ... Incident light, 6 ... White turbid part (scattering / reflecting part), 7 ... Light source, 8
… Reflector, 9… plastic optical fiber bundle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Ohara 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitate Works Ltd., Hitachi Research Laboratory (72) Shinichi Akasaka 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitate Works Co., Ltd. Hitachi Research Laboratory (72) Inventor Yasuhiro Koike 1-331-30 Ookayama, Meguro-ku, Tokyo 303

Claims (6)

[Claims] 1. A light transmission body made of transparent plastic, wherein a part of the light transmission body is provided with a cloudy portion for scattering and reflecting light. 2. The plastic optical transmission body according to claim 1, wherein the white turbid portion is provided in a branch path portion or a reflection portion having an angle equal to or less than a critical angle of light. 3. A light transmission body comprising a transparent plastic core portion for transmitting light and a clad portion surrounding the core portion, wherein a white turbid portion in which light is scattered and reflected is provided in a part of the core portion. A plastic optical transmission body characterized by being provided. 4. An optical transmission body in which optical transmission lines provided in a plastic substrate having two or more layers are connected by a plastic optical transmission body having a core and a clad, and light is scattered at the connecting portion of the core. A plastic optical transmission body having a white opaque portion that is reflected. 5. The plastic optical transmission article according to claim 1, wherein the cloudy portion is colored. 6. The plastic optical transmission article according to claim 1, wherein the cloudy portion is made of a copolymer.