JP2002022976A - Optical/electronic printed circuit board and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical/electronic printed circuit board of high reliability, a high density and a small size which simplifies the wiring work and allows the management of the bent parts of optical fibers as well, by laying the optical fibers into grooves formed in a photosensitive resin layer. SOLUTION: The photosensitive resin layer 3 is formed on at least one surface of the printed circuit board 2 formed with electronic circuit patterns 1 and is formed with the groove patterns corresponding to optical waveguide patterns by an exposure and development method. The optical fibers 5 are mounted and fixed into the grooves 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical / electronic printed wiring board and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional printed wiring board has electronic components mounted thereon and an electronic circuit conductor pattern for transmitting an electric signal is provided on one side or in multiple layers. For some high-speed circuit applications, electronic components and optical / electronic components are mixed on a printed wiring board, and after components are mounted, optical / electronic components are connected by optical fibers and optical wiring is performed.

[0003]

When a high-speed signal is transmitted to a conventional printed wiring board consisting only of electric conductor patterns, the signal waveform is distorted due to the influence of crosstalk from adjacent lines and reflection of the transmission signal. In addition, malfunctions occur, radiation noise is large, and the influence on other electronic devices is great. Also, in designing a high-speed circuit pattern of a printed wiring board, complicated wiring layout, pattern width, pattern spacing, and the like, require advanced wiring design techniques.

Further, when electronic components and optical / electronic components are mixedly mounted on a conventional printed wiring board and the optical / electronic components are connected by optical fibers after the components are mounted, the wiring connection of the optical fibers becomes complicated, There is a problem that the mounting density does not increase due to the extra fiber length. Furthermore, the optical fiber jumps out of the printed wiring board upward or toward the edge of the board, and extra space is required, and excessive pressure may be applied during the connection and handling of the optical fiber, causing breakage. As the radius becomes smaller, the optical transmission loss increases. Therefore, special care must be taken when connecting and handling the optical fiber.

In recent years, a method of manufacturing an optical fiber wiring board by inserting an optical fiber into a groove formed by screen printing is known (for example, Japanese Patent Application No. 10-198441). The method of forming a groove using printing has the following problems. The resin portions on both sides of the groove are bleeding or dripping, and the edge of the groove cannot be formed clearly. Therefore, insertion and temporary fixing of the optical fiber may not be performed, causing a problem. Fluctuations in the groove width are large. For example, when the groove width is 150 μm, a fluctuation of ± 30 μm or more occurs. In addition, the printing thickness varies greatly, for example, the thickness 1
In the case of 00 μm, a variation of ± 20 μm or more occurs. In particular, it is difficult to form continuous grooves at a narrow pitch. For example, in order to manufacture a fiber wiring board using an optical connector having an optical fiber connection pitch of 250 μm and an optical fiber having an outer diameter of 125 μm, a groove pitch of 250 μm is required.
Although a groove having a groove width of 130 μm is required, bleeding and dripping occur, and such a groove cannot be formed.

[0006]

SUMMARY OF THE INVENTION The present invention has been studied to solve the problems of the prior art, and has the following features. A photosensitive resin layer 3 having a groove pattern is formed on at least one surface of a printed wiring board 2 on which an electronic circuit pattern 1 is formed.
A photosensitive resin layer 3 having a groove pattern is formed on at least one surface of an optical / electronic printed wiring board on which an electronic circuit pattern 1 is formed, and an optical fiber 5 is mounted in a groove 4. And an optical / electronic printed wiring board in which the optical fiber 5 is coated with a resin 6, and an optical / electronic printed wiring board in which the optical fiber 5 is composed of only a core material and a clad material without a coating protective material.

Further, a photosensitive resin layer 3 is formed on at least one surface of the printed wiring board 2 on which the electronic circuit pattern 1 is formed, and a groove pattern corresponding to the optical waveguide pattern is formed by an exposure / development method. A method for manufacturing an optical / electronic printed wiring board in which an optical fiber 5 is mounted and fixed therein, a photosensitive resin layer 3 formed on at least one surface of a printed wiring board 2 on which an electronic circuit pattern 1 is formed, and an exposure / development method After forming a groove pattern corresponding to the optical waveguide pattern, mounting and fixing the optical fiber 5 in the groove 4, the optical fiber 5 is coated with a resin 6, a method of manufacturing an optical / electronic printed wiring board, and the optical fiber 5 is coated. This is a method for manufacturing an optical / electronic printed wiring board comprising only a core material and a clad material without a protective material. Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 shows an optical / electronic printed wiring board 2 according to the present invention.
0 is a perspective view, and FIG. 2 is a sectional view taken along the line AA in FIG. A photosensitive resin layer 3 having a groove pattern is formed on a printed wiring board on which an electronic circuit pattern 1 is formed. The photosensitive resin layer 3 may be formed on all of one surface, all of both surfaces, or may be formed only on a necessary portion of one surface.

An optical fiber 5 is mounted and fixed in the groove 4. The peripheral surface of the optical fiber 5 is not covered and protected, and is composed of only a core material and a clad material. Examples of the optical fiber include a silica-based optical fiber and a polymer-based optical fiber, but are not particularly limited. A plurality of optical fibers may be mounted and fixed in the groove 4.

The means for mounting and fixing the optical fiber 5 in the groove 4 may be fixed by an adhesive such as an epoxy adhesive or a photosensitive adhesive, or fixed by a tape with an adhesive.

The printed wiring board includes, but is not particularly limited to, organic base materials such as glass epoxy and glass polyimide and ceramic base materials, and is not particularly limited. Either way, the groove 4 may be formed on both sides in addition to one side.

The photosensitive resin layer 3 is made of a resin which cures only by ultraviolet rays, a resin which cures by heating after irradiation of ultraviolet rays, or a resin which reacts by irradiation with an electron beam. The photosensitive resin layer 3 in FIG. 2 is formed by applying a photosensitive liquid resin or laminating a photosensitive film.

Further, as shown in FIG. 3, a solder resist layer 7 may be separately formed, and the photosensitive resin layer 3 may be formed thereon.

FIG. 4 is a cross-sectional view of an optical / electronic printed wiring board 22 in which a photosensitive resin layer 3 is formed in the same manner as FIG. .

FIG. 5 shows an optical / electronic printed wiring board 2 of the present invention.
0 is a cross-sectional view schematically showing a manufacturing method of No. 0. First, a photosensitive resin layer 3 is formed on the surface of a printed wiring board 2 on which an electronic circuit pattern 1 has been formed. Next, using a mask 9 corresponding to the groove pattern for mounting an optical fiber, ultraviolet rays, an electron beam, or the like is irradiated and cured, followed by development to form the grooves 4.
Thereafter, the optical fiber 5 is mounted and fixed in the groove 4.
Although not shown, a pattern corresponding to the component mounting pattern and the component mounting hole is naturally formed on the mask 9 in order to provide an opening.

FIG. 6 is a cross-sectional view of an optical / electronic printed wiring board 23 showing still another embodiment.
The optical fiber 5 is fixed in the groove 4 and filled with a resin 6.

[0017]

【Example】

Example 1 A photosensitive liquid resin was spray-coated on a surface of a printed wiring board having an electronic circuit pattern formed on one surface of a glass epoxy substrate so as to have a thickness of 70 μm. Next, using a mask corresponding to the opening for component mounting, in addition to the groove pattern for mounting the optical fiber, the substrate is exposed to ultraviolet rays and developed, and the groove pitch is 250 μm and the groove width is 135 μm
An m-shaped groove pattern and an opening for component mounting were formed, and were heated and cured. As a result of measurement, the groove width was 135 ± 10μ
m and thickness were 70 ± 10 μm. Thereafter, a quartz optical fiber having an outer diameter of φ125 μm without a coating protective material such as a plastic material was mounted and fixed in the groove using a photosensitive adhesive to obtain an optical / electronic printed wiring board of Example 1. .

[0018]

EXAMPLE 2 A solder resist was applied to the surface of a printed wiring board having an electronic circuit pattern formed on one surface of a glass epoxy substrate, and a photosensitive liquid resin was spray-coated to a thickness of 70 μm. It was manufactured in the same manner as in Example 1 to obtain an optical / electronic printed wiring board of Example 2.

[0019]

Example 3 An electronic circuit pattern was formed on one surface of a glass epoxy substrate, and a photosensitive resin film was laminated to form a photosensitive resin layer having a thickness of 70 μm. Next, in addition to a groove pattern for mounting an optical fiber, using a mask corresponding to an opening for mounting a component, the substrate is exposed to ultraviolet rays and developed, and a groove pattern having a groove pitch of 250 μm and a groove width of 135 μm and a component mounting are formed. Openings were formed and heated to cure. As a result of the measurement, the groove width was 135 ± 10 μm and the thickness was 7
It was 0 ± 5 μm. Thereafter, a quartz optical fiber having an outer diameter of φ125 μm without a coating protective material such as a plastic material was mounted and fixed in the groove using a photosensitive adhesive to obtain an optical / electronic printed wiring board of Example 3. .

[0020]

Fourth Embodiment A quartz optical fiber is mounted and fixed in a groove using a photosensitive adhesive in the same manner as in the first embodiment, and a photosensitive resin is further filled in the groove and on the optical fiber to protect the optical fiber. An optical / electronic printed wiring board of Example 4 was obtained.

[0021]

According to the present invention, the signal transmission speed can be improved by forming a part of the metal wiring, which is the signal transmission circuit of the conventional printed wiring board, with an optical fiber, and malfunction due to noise from the surrounding signal lines can be prevented. Can also be
There is an effect that the noise is not radiated from the optical fiber to the outside, and the reliability is improved. Also, there is an effect that complexity of designing a high-speed circuit pattern of a printed wiring board can be eliminated.

Further, since optical wiring between the optical and electronic parts is performed by mounting and fixing the optical fiber in advance in the groove formed by the photosensitive resin layer on the printed wiring board, many optical fibers can be easily wired. It can be laid out in order and high density,
The optical fiber does not jump out of the printed wiring board in the upward direction or the board edge direction, and a high-density, small-sized optical and electronic printed wiring board can be provided.

Further, by using an optical fiber comprising only a core material and a clad material without a coating protective material, the density can be further increased. The groove pattern exposes the photosensitive resin layer.
Since it is formed by development, the optical fiber wiring pattern can be easily changed, and there is also an effect that a highly accurate groove pattern can be formed.

Further, since the optical fiber is mounted in the groove of the photosensitive resin layer formed on the surface of the printed wiring board, the damage of the optical fiber can be prevented and the handling is easy. In addition, the bending portion of the optical fiber where optical transmission loss is likely to occur due to handling can be regulated and controlled by the bending radius of the groove. Further, by filling the groove with an optical fiber and then filling it with a resin, it is possible to provide an optical / electronic printed wiring board with further improved reliability against the influence of pressure and humidity.

In addition, the present invention employs a method in which a photosensitive liquid resin is applied or a photosensitive resin film is laminated to form a photosensitive resin layer and a groove is formed by exposure and development. Edge can be formed clearly,
It is possible to obtain a highly accurate groove with small variations in width and thickness. Therefore, the work of mounting the optical fiber in the groove can be easily performed, and the yield can be improved.
Also, grooves continuous at a narrow groove pitch, for example, groove pitch 2
A groove of 50 μm and a groove width of 130 μm can also be formed.

[Brief description of the drawings]

FIG. 1 is a perspective view of an optical / electronic printed wiring board according to the present invention.

FIG. 2 is a configuration sectional view taken along line AA in FIG.

FIG. 3 is a configuration sectional view showing another embodiment.

FIG. 4 is a configuration sectional view showing another embodiment.

FIG. 5 is a schematic cross-sectional view illustrating a method for manufacturing an optical / electronic printed wiring board according to the present invention.

FIG. 6 is a configuration sectional view showing another embodiment.

FIG. 7 is a perspective view of a conventional optical / electronic printed board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic circuit pattern 2 Printed wiring board 3 Photosensitive resin layer 4 Groove 5 Optical fiber 5 'Optical fiber 6 Resin 7 Solder resist layer 8 Coating protective material 9 Mask 11 Electronic component 12 Optoelectronic component 20 Optical / electronic printed wiring board 21 Optical Electronic printed wiring board 22 Optical / electronic printed wiring board 23 Optical / electronic printed wiring board 30 Optical / electronic printed board

Claims (6)

[Claims] 1. A printed wiring board on which an electronic circuit pattern is formed, a photosensitive resin layer having a groove pattern formed on at least one surface, and an optical fiber mounted in a groove. Optical and electronic printed wiring boards. 2. A photosensitive resin layer 3 having a groove pattern is formed on at least one surface of a printed wiring board 2 on which an electronic circuit pattern 1 is formed, and an optical fiber 5 is mounted in a groove 4. An optical / electronic printed wiring board characterized by being coated with a resin 6. 3. The optical / electronic printed circuit board according to claim 1, wherein the optical fiber comprises only a core material and a clad material having no coating protective material. 4. A photosensitive resin layer 3 is formed on at least one surface of a printed wiring board 2 on which an electronic circuit pattern 1 is formed, and a groove pattern corresponding to an optical waveguide pattern is formed by an exposure / development method. A method for manufacturing an optical / electronic printed wiring board, wherein an optical fiber 5 is mounted and fixed in the inside. 5. A photosensitive resin layer 3 is formed on at least one side of a printed wiring board 2 on which an electronic circuit pattern 1 is formed, and a groove pattern corresponding to an optical waveguide pattern is formed by an exposure / development method. A method for manufacturing an optical / electronic printed wiring board, comprising: mounting and fixing an optical fiber 5 inside the optical fiber; and coating the optical fiber 5 with a resin 6. 6. The method for manufacturing an optical / electronic printed wiring board according to claim 4, wherein the optical fiber comprises only a core material and a clad material having no coating protective material.