JPH04125502A - Resin-made optical circuit board and its manufacture, and domestic electric appliance using the same - Google Patents

Abstract

PURPOSE:To obtain the inexpensive optical circuit board which has superior optical characteristics and large mechanical strength by constituting a clad part in two-layered structure of a substrate and a skin layer covering its surface. CONSTITUTION:The clad part is constituted in the two-layered structure of the substrate 1 and the skin layer 2 which covers its surface; and the substrate 1 of the clad part is formed of a material which has larger mechanical strength and higher heat resistance than the skin layer 2, which is formed of a material which has a lower refractive index than a core part 1. Consequently, only the skin layer positioned at the periphery of the core part is considered as to the low refractive index of the clad material 1 and an inexpensive material which is easily obtained in consideration of mechanical strength and heat resistance can be selected as the substrate material of the clad part 1 without considering the refractive index. Namely, the mechanical strength and heat resistance of the clad part of the optical circuit board are obtained with the substrate and the optical characteristics are realized with the skin layer; even when inexpensive fluororesin of several mum order in actual use is used for the skin layer, the price is made lower than before.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin optical circuit board, a method for manufacturing the same, and a household electrical appliance using the resin optical circuit board.

[Prior art] A core part that transmits light and a portion surrounding the core part! In addition, resin optical circuit boards consisting of a cladding portion with a lower refractive index than the core portion have recently been attempted to be used as circuit boards for household electrical appliances that contain a large amount of information, such as video tape recorders and personal computers. ing.

For example, the optical circuit board described above transmits the read signal as it is when the video signal is directly recorded on the tape as an optical signal, and when the video signal is recorded as an electrical signal, it is converted into an optical signal. This means replacing and transmitting the data.

The prior art related to optical circuit boards is, for example, disclosed in Japanese Patent Application Laid-open No. 5
No. 5-120004, No. 60-15606, No. 60-
No. 114811, No. 61-500941, No. 63-2
It is described in No. 50609 and No. 63-316805.

[Problem to be solved by the invention]

By the way, as mentioned above, a resin optical circuit board is composed of a core portion having a high refractive index and a cladding portion located around the core portion and having a lower refractive index than the core portion. .

The core part transmits light, and is required to be highly transparent, such as polymethyl methacrylate (PMMA). Additionally, plastic optical fibers connected to optical circuit boards generally use PMMA;
A has a refractive index of 1°49, which is lower than that of ordinary resins.

Therefore, when PMMA is used as the core material of an optical circuit board, it is necessary to use a fluororesin with a lower refractive index for the cladding part.

However, although fluororesins have a low refractive index (and have excellent optical properties as a cladding material), they have low mechanical strength, low heat resistance, and are also expensive.

The object of the present invention is to provide an optical circuit made of a resin that has a lower refractive index than the core part, excellent optical properties as a cladding material, high mechanical strength, high heat resistance, and, in addition, is inexpensive. The object of the present invention is to provide a board, a method for manufacturing the same, and a household electrical appliance using the resin optical circuit board.

[Means to solve the problem]

A resin optical circuit board according to the present invention includes a core portion for electrically transmitting light, and a cladding portion located around the core portion and having a lower refractive index than the core portion, the cladding portion comprising: It has a two-layer structure consisting of a substrate and a skin layer covering its surface, and the substrate of the cladding part is made of a material that has greater mechanical strength and high heat resistance than the skin layer, and the skin layer It is characterized by being made of a material whose refractive index is lower than that of the other parts.

In addition, the method for manufacturing a resin optical circuit board according to the present invention involves injection molding a mixture of a cladding substrate material with high viscosity and a skin layer material with low viscosity, and forming a surface of the substrate material with high viscosity and low fluidity. It is characterized by being coated with a skin layer material that has low viscosity and high fluidity.

Furthermore, the household appliance according to the present invention includes a core portion for electrically transmitting light, and a cladding portion located around the core portion and having a lower refractive index than the core portion, and the cladding portion is connected to a substrate. The substrate of the cladding part has a two-layer structure including a skin layer covering the surface thereof, and the substrate of the cladding part has greater mechanical strength (and is made of a material with high heat resistance) than the skin layer, and the skin layer has a It is characterized in that a resin optical circuit board made of a material with a lower refractive index than the core part is incorporated as a circuit board.

[Effect]

Therefore, in the resin optical circuit board according to the present invention, the cladding portion located around the optical transmission core portion has a two-layer structure of the substrate and the skin layer covering the surface of the substrate. According to the authors, unlike conventional optical circuit boards, a single-layer cladding cannot simultaneously satisfy all of the requirements for optical, mechanical, and thermal properties, and is therefore expensive. Unlike the conventional cladding material, the low refractive index of the cladding material only needs to be considered for the skin layer located around the core. It is possible to select inexpensive materials that are easy to use and that take into account heat resistance and heat resistance. In other words, the mechanical strength and heat resistance of the cladding portion of the optical circuit board should be provided by the substrate, and the optical characteristics should be provided by the skin layer.

In actual use, the skin layer described above may be on the order of several A1 m, and the amount of resin used therein is sufficient. Therefore, even if an expensive fluororesin is used for the skin layer, the price of the optical circuit sheet metal body can be made cheaper than before.

In addition, the resin optical circuit board according to the present invention is manufactured by injection molding a mixture of a cladding substrate material with high viscosity and a skin layer material with low viscosity, and molding the mixture on the surface of the substrate material with high viscosity and low fluidity. On the other hand, the main purpose of this method is to coat the skin layer material with low viscosity and high fluidity. According to this method, it is possible to simultaneously shorten the work process and save labor. can. In other words, when making two layers of different types of synthetic resin materials, usually one
The method of the present invention requires two steps: after forming a layer, and then overlaying this one layer with another layer. On the other hand, it is possible to coat a skin layer material with low viscosity (high fluidity), and according to this molding method, the cladding part can be molded in one step, which shortens this type of work process and reduces work. Labor saving can be achieved at the same time.

Furthermore, when the optical circuit board is applied as a circuit board for a home appliance with a large amount of information, such as a video tape recorder or a microcomputer, all the effects produced by the optical circuit board described above can be enjoyed. This type of product can be obtained which is excellent in terms of equipment reliability and economical efficiency.

〔Example〕

Each embodiment of the present invention will be described below.

1st Embodiment In FIG. 2, l indicates a substrate of a cladding part constituting an optical circuit board, and this substrate 1 is made of polycarbonate (hereinafter referred to as
PC) was mixed with carbon black and molded using an injection molding machine 4 and a mold 5 shown in FIG.

In addition, in FIG. 5, 3 indicates the resin for the substrate.

After molding the substrate 1, the substrate 1 is immersed in an emulsion of the skin layer resin using a fluorine-containing methacrylate resin (hereinafter abbreviated as FMMA) as a skin layer. As shown in the figure, a cladding portion was obtained in which an I Niskin layer 2 was formed on a substrate I.

On the other hand, polymethyl methacrylate (hereinafter abbreviated as PMMA) was used as the core material, and the core portion of the optical circuit board was obtained by injection molding in the same manner as the cladding portion.

Note that the clad part and the core part were molded using separate molds, and then the clad part was attached to the upper surface layer of the core part to obtain an optical circuit board.

That is, in the resin optical circuit board according to the present invention, the cladding portion located around the optical transmission core portion has a two-layer structure of the substrate 1 and the skin layer 2 covering the surface thereof, According to this, unlike conventional optical circuit boards, a single-layer cladding section cannot simultaneously satisfy all of the requirements for optical properties, mechanical properties, and thermal properties, and is expensive. Unlike, the low refractive index as a clad material,
Only the skin layer 2 located around the core part needs to be considered, and therefore, the substrate material of the cladding part does not take into account the refractive index (mechanical strength and heat resistance are taken into consideration).
It is possible to select inexpensive materials that are easy to use. Also,
In actual use, the skin layer 2 described above may be on the order of several micrometers, and the amount of resin used therein is sufficient. Therefore, even if an expensive fluororesin is used for the skin layer 2, the price of the optical circuit sheet metal body can be made cheaper than before.

The optical signal from the optical circuit board obtained as described above can be extracted only from the core part, and this is because the light leaking from the core part is absorbed by the carbon black and the parts outside the core part are This is because light cannot be transmitted.

Second Embodiment In FIG. 3, reference numeral 1 indicates a substrate of a cladding part constituting an optical circuit board, and reference numeral 2 indicates a skin layer. In this embodiment, PC is used for the substrate 1, and FMMA is used for the skin layer 2. A cladding portion was obtained through the same procedure as in the first example.

On the other hand, as in the first example, PMMA was used as the core material, and the molding method thereof was the same as in the first example.

In the case of this example, since carbon black is not included in the substrate 1, it has been experimentally confirmed that the optical signal from the optical circuit board obtained as described above leaks to areas other than the core. Since the strength of the optical signal between the core and other parts differs greatly, there was no problem in actual use by appropriately selecting the threshold of the transmission signal.

Third Embodiment In FIG. 4, 1 indicates a substrate of a cladding part constituting an optical circuit board, and 2 indicates a skin layer.
As in the first example, PC mixed with carbon black was used for the skin layer 2, and FMMA was used for the skin layer 2, and a cladding part was obtained through the same procedure as in the first example.

On the other hand, as in the first example, PMMA was used as the core material, and the molding method thereof was the same as in the first example.

In this embodiment, the difference from the first embodiment (Fig. 1) is that the core mounting part is not only attached to one side of the cladding part.
This is achieved by forming convex portions corresponding to the core portions on both surfaces of the mold cavity surface.

The configuration of the optical circuit board in this example is as described above, and the optical signal from the optical circuit board made as described above is as follows.
The light can only be extracted from the core sections provided on both sides of the cladding section. This is because the light leaking from the core sections on both sides of the optical circuit board is absorbed by the carbon black, and the light is not transmitted anywhere other than the core section. Therefore, according to this embodiment, it is possible to prevent crosstalk between the core parts provided on both sides of the optical circuit board, and when the core parts are provided on both sides of the optical circuit board in this way, The circuit arrangement density can be increased compared to the case where the core portion is provided on one side of the board.

By the way, as mentioned above, the structure that prevents crosstalk between the negative core part and other core parts and increases the circuit arrangement density of the core part with respect to the optical circuit board is as shown in FIG. This can be achieved not only by arranging both sides of the optical circuit board facing each other, but also by narrowing the distance between adjacent core parts on the same side of the optical circuit board, or by embedding the core parts in the cladding part. good.

In the first to third embodiments, the cross-sectional shape of the core mounting portion formed in the cladding portion of the optical circuit board is square. There is no problem in adopting a circular shape.

Further, in the first to third embodiments, after the substrate l of the cladding part constituting the optical circuit board is injection molded, the cladding part is obtained by immersing the substrate l in an emulsion of the skin layer resin. However, according to this method, two steps are required: molding the substrate 1 and immersing the substrate 1 in an emulsion of the skin layer resin.

On the other hand, if injection molding is performed by mixing materials with different fluidity, that is, a substrate material with high viscosity and a skin layer material with low viscosity, the viscosity will be lower than the surface of the substrate material with high viscosity and low fluidity. It is possible to cover the skin layer material with low fluidity, and according to this molding method, the cladding part can be molded in one step, achieving shortening of the work process and labor saving at the same time. be able to.

Furthermore, when injection molding the substrate 1 constituting the front rad portion, the skin layer material may be placed inside the mold and then the substrate material may be injection molded.

Further, in the first to third embodiments, the core material of the optical circuit board is injection molded onto the cladding part, but instead of this, the core part may be obtained by casting. Good too.

Fourth Embodiment FIG. 6 is a plan view of a recorder chassis showing a fourth embodiment in which the optical circuit board according to the present invention is applied to a video tape recorder, which is a household electrical appliance.

In Fig. 6, 100 is the core part of the optical circuit board, 200 is the cladding part, 6 is the cabstan motor of the video tape recorder, 7 is the capstan motor mounting base, 8 is the tape guide guide hole, and 9 is the rotary drum hole. It shows.

Therefore, when the video signal is directly recorded on the tape as an optical signal, the optical circuit board transmits the read signal as it is, and when the video signal is recorded as an electrical signal, the optical circuit board transmits the read signal as it is. When the optical circuit board according to the present invention is used as a circuit board for a household electrical appliance with a large amount of information, such as a video tape recorder or a personal computer, the first to third All the effects described in the embodiments can be enjoyed.

[Effects of the Invention] The present invention is as described above, and the resin optical circuit board according to the present invention has a structure in which the cladding portion located around the optical transmission core portion is connected to the substrate and its surface as described above. It has a two-layer structure with a covering skin layer, and according to this, unlike conventional optical circuit boards, the cladding part composed of one layer has optical properties, mechanical properties, and thermal properties. Unlike the case where it is not possible to satisfy all of the above conditions at the same time and the price is high, the low refractive index of the cladding phase only needs to be considered for the skin layer located around the core, and therefore the cladding phase has a low refractive index. As the substrate material, it is possible to select an easily available and inexpensive material that takes into consideration mechanical strength and heat resistance without considering the refractive index.

In other words, the mechanical strength of the gland part in the optical circuit board,
It is sufficient that the substrate has sufficient heat resistance, and that the skin layer has sufficient optical properties. The skin layer described above may have an actual value on the order of several micrometers, and the amount of resin used therein is sufficient to be extremely small. Therefore, even if an expensive fluororesin is used for the skin layer, the price of the optical circuit sheet metal body can be made cheaper than before.

In addition, the resin optical circuit board according to the present invention can be manufactured by injection molding a mixture of a cladding substrate material with high viscosity and a skin layer material with low viscosity. The purpose of this method is to coat the surface with a skin layer material that has low viscosity (high fluidity), and this method simultaneously achieves shortening of this type of work process and labor saving. In other words, when creating two layers of different types of synthetic resin materials, there are usually two steps: first forming one layer, and then overlaying this one layer with another layer. However, in the method of the present invention, a skin layer material with low viscosity and high fluidity can be coated on the surface of a substrate material with high viscosity and low fluidity, and this molding method has the following advantages: According to this method, the cladding portion can be formed in one step, and it is possible to simultaneously achieve shortening of this type of work process and labor saving.

Furthermore, when the optical circuit board is applied as a circuit board for a home appliance with a large amount of information, such as a video tape recorder or a microcomputer, all the effects produced by the optical circuit board described above can be enjoyed. This type of product can be obtained which is excellent in terms of both reliability, equipment reliability, and economy.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a resin optical circuit board showing a first embodiment of the present invention, FIG. 2 is a perspective view of the substrate 1 before forming the skin layer 2 shown in FIG. 1, and FIG. The figure is a perspective view of a resin optical circuit board showing a second embodiment of the present invention, FIG. 4 is a longitudinal sectional view of a resin optical circuit board showing a third embodiment of the invention, and FIG.
The figure is a schematic configuration diagram of an injection molding machine used to carry out the present invention, and FIG. 6 shows a fourth embodiment in which the resin optical circuit board according to the present invention is applied to a video tape recorder, which is a household electrical appliance. It is a top view of the chassis for recorders. 1. Clad board of resin optical circuit board, 2. Skin layer of the same. Agent: Patent attorney Akio Takahashi (and one other person) Figure 1: Resin optical circuit board cladding board 2...
・・・Same 7th layer diagram diagram diagram diagram diagram

Claims (1)

[Claims] 1. In a resin optical circuit board comprising a core portion for electrically transmitting light and a cladding portion located around the core portion and having a lower refractive index than the core portion, the cladding portion is , has a two-layer structure consisting of a substrate and a skin layer covering the surface thereof, the substrate of the cladding part is made of a material having greater mechanical strength and high heat resistance than the skin layer, and the skin layer is A resin optical circuit board characterized in that it is made of a material having a lower refractive index than the core part. 2. The resin optical circuit board according to claim 1, wherein a light absorbing substance is mixed into the substrate constituting the cladding part. 3. The resin optical circuit board according to claim 2, wherein the light absorbing substance mixed into the substrate constituting the cladding portion is carbon black. 4. A cladding substrate material with high viscosity and a skin layer material with low viscosity are mixed and injection molded, and the surface of the substrate material with high viscosity and low fluidity is coated with the skin layer material with low viscosity and high fluidity. A method for manufacturing a resin optical circuit board, characterized in that: 5. It consists of a core part that electrically transmits light, and a cladding part located around the core part and having a lower refractive index than the core part, and the cladding part is combined with a skin layer covering the substrate and its surface. It has a two-layer structure, and the substrate of the cladding part is made of a material with higher mechanical strength and higher heat resistance than the skin layer, and the skin layer is made of a material with a lower refractive index than the core part. A household electrical appliance characterized by incorporating the constructed resin optical circuit board as a circuit board.