JP2003098402A - Optical mounting substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an electronic instrument simplly, in lightweight and small size for transmitting information by using an optical signal between electronic equipment boards. SOLUTION: An electronic equipment board 2a provided with an integrated circuit and a light emitting part 21a and an electronic equipment board 2b provided with an integrated circuit and an integrated circuit 22a with a light receiving terminal are attached to a light guide plate 3a for transmitting the optical signal R between the integrated circuit 21a with the light-emitting terminal and the integrated circuit 22a with the light receiving terminal. The electronic equipment board 2a and the electronic equipment board 2b are attached across the light guide plate 3a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical mounting board, and more particularly to a method for increasing the density and size of the optical mounting board and an expanding method.

[0002]

2. Description of the Related Art Conventionally, in a circuit board on which various integrated circuits (ICs) such as CPU and memory and system LSI are mounted, performance such as operating frequency (or processing speed) and circuit function of CPU and memory are provided. Each I with the improvement of
It has become necessary to transmit electric signals in electric wiring such as a data bus connecting Cs in a bus structure at high speed.

Therefore, the bus connecting the ICs must be
The operating speed of the bus is being improved by shortening the electrical wiring length and promoting differential transmission.

However, in the method of shortening the wiring distance, various problems such as impedance mismatch and crosstalk occur, and when the wiring distance has to be lengthened due to a change or addition of a system, high speed transmission is impossible. The signal delay causes the system processing speed to be limited by the operating speed of the bus.

That is, when the distance between the ICs according to the operating frequency of the CPU reaches a limit and a high-speed CPU is mounted on a board and signals are transmitted at high speed by electric wiring, the wiring length and It can only be achieved in a fixed shape.

Also in the circuit board used in the image forming apparatus or the like, even when the image reading clock becomes faster with the increase in the resolution of the CCD, similarly, the pattern design of the electric wiring becomes very difficult. Become.

Electromagnetic noise (EMI: Electo) due to high density of bus connection wiring and high speed of system.
The problem of "romantic interference" is also a major limitation for improving the processing speed of the system. In particular, in a substrate such as a high-density mounting (MCM: multi-chip module) or a system LSI, since the data transfer speed (electric signal transmission speed) is increased,
EMI countermeasures become difficult.

Therefore, in order to solve such a problem and to improve the operating speed of the bus, an optical transmission technique is used in the circuit board and a portion for high-speed transmission in the board or between the boards is
Attempts have been made to convert electrical signals into optical signals for transmission. As one of the attempts, a technique is known in which a light guide plate having an optical element is attached to an electric component substrate having an optoelectronic element to form an optical mounting substrate, and information is transmitted in the electric component substrate via the light guide plate. There is.

[0009]

By the way, in the conventional method of transmitting information through the light guide plate attached to the electric component board, the electronic component such as an integrated circuit can be attached only to one surface of the electric component substrate. There is a problem that it is difficult to increase the density of the substrate and downsize the electronic device. Further, in the conventional optical mounting board, in order to transfer information between different electric mounting boards, it is necessary to connect these electric mounting boards with a conductive wire, an optical fiber or the like. There is a problem in that it is costly and it is difficult to reduce the size and weight of these electronic devices.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical mounting substrate which facilitates downsizing, weight reduction and function expansion of electronic equipment. .

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is an optical device which is attached to an electronic equipment main body and which transmits information between a plurality of electronic components or electronic circuits by optical signals. In the mounting substrate, among the light emitting unit that converts an electrical signal into an optical signal and emits the optical signal, and the light receiving unit that receives the optical signal and converts the optical signal into an electrical signal,
An electrical component board having both or one of them, made of a light-transmissive material, attached to the electrical component board,
A light guide plate for transmitting the optical signal is provided, and the electrical component board and the light guide plate are alternately superposed and connected in the thickness direction.

According to the first aspect of the present invention, an electronic device for transmitting a large amount of information between or within the electronic substrate can be formed in a lightweight and small size, and the electronic device can be easily and inexpensively manufactured. be able to. Further, by covering the incident portion and the emission portion of the optical signal of the light guide plate with the electrical equipment substrate, it is possible to reduce the failure of the optical mounting substrate due to the attachment of dust to the light guide plate.

According to a second aspect of the present invention, in the optical mount board according to the first aspect, at least one of the two electrical component boards mounted on both sides of the one light guide plate emits light. And a light receiving unit is provided on the other electrical component board, the light emitting unit and the light receiving unit are arranged at positions not overlapping each other, and the optical signal emitted from the light emitting unit is the light guide plate. And is transmitted to the light receiving unit via the.

According to a third aspect of the present invention, in the optical mounting board according to the first aspect, at least a light emitting portion is provided on one surface of one of the electrical component boards, and at least a light receiving portion is provided on the other surface. The light emitting unit and the light receiving unit are arranged at positions where they do not overlap with each other, the electrical component board is sandwiched between the two light guide plates, and the optical signal emitted from the light emitting unit is on the light emitting unit side. Emitted from the light guide plate of
It is characterized in that the light is received by the light receiving portion after penetrating the electrical equipment substrate and entering the light guide plate on the light receiving portion side.

According to a fourth aspect of the present invention, in an optical mounting board which is attached to an electronic equipment main body and carries out information transmission between a plurality of electronic components or electronic circuits by optical signals, the electrical signals are converted into optical signals, A light emitting unit that emits an optical signal,
An electric component board having a light receiving part for receiving an optical signal and converting the optical signal into an electric signal, and a light guide plate made of a material having a light-transmitting property, which is attached to the electric component board and transmits the optical signal, And a light emitting section is provided on one surface of the electrical component substrate, and a light receiving section for receiving an optical signal emitted by the light emitting section is provided on the other surface.

According to the invention described in claim 4, an electronic device for transmitting a large amount of information between or within the electronic substrate can be formed in a lightweight and small size, and the electronic device can be easily and inexpensively. Can be created.

According to a fifth aspect of the present invention, in the optical mounting board according to the fourth aspect, the light emitting portion and the light receiving portion are arranged at positions not overlapping each other, and an optical signal emitted from the light emitting portion is generated. The optical signal is transmitted to the light receiving unit via the light guide plate, and the optical signal penetrates through the electrical board in the process of transmission.

According to a sixth aspect of the present invention, in an optical mounting board which is attached to an electronic equipment main body and transmits information between a plurality of electronic components or electronic circuits by optical signals, the electrical signals are converted into optical signals, A light emitting unit that emits an optical signal,
An optical board having both or one of a light receiving section for receiving an optical signal and converting the optical signal into an electric signal; and an optical board made of a material having a light-transmitting property. And a light guide plate for transmitting the light, and one light guide plate is connected to the electric component board by bridging at least two or more of the electric component boards, and the light guide plate transmits light between different electric component boards. A signal is transmitted.

According to the sixth aspect of the present invention, it is possible to manufacture an electronic device that transmits a large amount of information between the electric component boards in a small size, a light weight and a low cost.

According to a seventh aspect of the present invention, in the optical mounting board according to the fifth aspect, the two or more electrical component boards are arranged at mutually different angles, and the light guide plate is two.
It is characterized in that it has a curved shape at a bridge portion between a plurality of electrical equipment substrates.

According to an eighth aspect of the present invention, in the optical mounting board according to the sixth or seventh aspect, at least one or more of the electrical components out of the at least two or more electrical components substrates to which the light guide plate is connected. The substrate is detachably connected to the light guide plate.

According to a ninth aspect of the present invention, in the optical mounting board according to the eighth aspect, at least one or more of the electrical component boards connected to the light guide plate are detachably connected to the light guide plate. While having a light emitting portion that emits an optical signal toward the light receiving portion provided on the other electrical component board, when the other electrical component board is not connected to the light guide plate, the light emitting portion outputs an optical signal. It is characterized by not emitting light.

According to a tenth aspect of the present invention, there is provided an optical mounting board which is attached to an electronic device body and which transmits information between a plurality of electronic components or electronic circuits by an optical signal. A main optical mounting board for transmitting information between electronic circuits by optical signals; and an optical mounting module detachably connected to the main optical mounting board for transmitting information between a plurality of electronic components or electronic circuits by optical signals, The main optical mounting board and the optical mounting module are provided with a light emitting section for converting an electrical signal into an optical signal and emitting the optical signal, and receiving the optical signal and transmitting the optical signal as the electrical signal. Among the light receiving parts for converting into, the electrical component board having both or one of them, and a light guide plate made of a light-transmissive material and attached to the electrical component board for transmitting the optical signal. In addition, when the main optical mounting board and the optical mounting module are connected, the electrical mounting board provided on the main optical mounting board and the electrical mounting board provided on the optical mounting module are electrically connected. With
The light guide plate provided on the main optical mounting substrate and the light guide plate provided on the optical mounting module are optically connected.

According to the tenth aspect of the present invention, an electronic device for transmitting a large amount of information between electrical equipment substrates can be manufactured in a small size, a light weight, and a low cost, and a function expansion substrate provided with an optical data bus in the electronic device. It becomes extremely easy to expand the functions by using the above and to apply a memory module having an optical data bus.

According to an eleventh aspect of the present invention, in the optical mounting board according to the tenth aspect, the two light-emitting parts provided on the main optical mounting board are connected to the optical mounting board.
One or both of a light emitting section and a light receiving section provided in one or more optical mounting modules, and a light receiving section and light emission provided in the two or more optical mounting modules connected to the main optical mounting substrate. A plurality of optical paths for transmitting an optical signal are provided between the optical path and both or any one of the sections, and the optical path lengths of the optical paths are equal to each other.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of a preferred embodiment of the present invention will be specifically described with reference to the drawings.

(First Embodiment) First, the structure of the optical mounting board of the present invention will be described with reference to FIG. FIG. 1 is a side sectional view showing a configuration of an optical mounting board according to a first embodiment of the present invention. The optical mounting board 1 of the present embodiment is configured by, for example, two electrical component boards 2a and 2b being attached to the light guide plate 3a so as to sandwich the light guide plate 3a.

On one of the electric component boards 2a, an integrated circuit section,
An IC 21a with a light emitting terminal is provided, which includes a light emitting portion that converts an electric signal transmitted from the integrated circuit portion into an optical signal R and emits light toward the light guide plate 3a side. Further, the other electrical component board 2b has a light receiving terminal provided with an integrated circuit portion and a light receiving portion for receiving the optical signal R emitted from the light guide plate 3a, converting the optical signal R into an electric signal, and transmitting the electric signal to the integrated circuit portion. The IC 22a is provided. Furthermore, in addition to the IC 21a with the light emitting terminal and the IC 22a with the light receiving terminal, electronic components, conducting wires, etc. are attached to the electric component boards 2a, 2b as necessary.

Here, the light emitting terminal-equipped IC 21a and the light-receiving terminal-equipped IC 22a are arranged at positions where they do not overlap each other when the optical mounting board 1 is formed. Further, an IC 21a with a light emitting terminal and an IC 22a with a light receiving terminal
When the optical mounting board 1 is formed, is attached to the light guide plate 3a so as to face outward. By mounting the IC 21a with the light emitting terminal and the IC 22a with the light receiving terminal in such an orientation, the IC 21a with the light emitting terminal and the IC 2 with the light receiving terminal
Since the heat generated during the operation of the 2a is easily released, it is possible to reduce the size and weight of the electronic device provided with the optical mounting board 1 and to easily maintain the electronic device.

The light emitting portions respectively provided in the IC 21a with a light emitting terminal and the IC 21b with a light emitting terminal described later are formed of, for example, a semiconductor laser having a predetermined emission wavelength and output intensity. Further, the light receiving portions provided in the IC 22a with a light receiving terminal and the IC 22b with a light receiving terminal described later respectively,
For example, it is formed by a phototransistor having a light receiving diameter capable of receiving the signal light R.

Further, holes 24a1 and 24b1 through which the optical signal R passes are appropriately formed in the electrical component boards 2a and 2b at positions overlapping the light emitting portion of the IC 21a with a light emitting terminal and the light emitting portion of the IC 22a with a light receiving terminal. ing.

The light guide plate 3a is the IC 21a with the light emitting terminal.
Is an optical data bus for transmitting an optical signal R from the IC 22a with the light receiving terminal, and its main body is a plate-like body made of a material having high translucency and a high refractive index, for example, a thickness of about 5 mm. is there. The light guide plate 3a has optical elements 31a1 and 31a having a shape of, for example, a triangular prism that totally reflects the optical signal R.
a2 is an IC2 with a light emitting terminal when the optical mounting board 1 is formed.
The light emitting portion 1a and the light receiving portion of the IC 22a with the light receiving terminal are provided so as to overlap with the light receiving portion.

The optical elements 31a1, 31a2 and the optical elements 31b1, 31b2, ... The light signal R emitted from the light emitting terminal ICs 21a, ... Reaches the light receiving terminal ICs 22a, .. Let
The material, shape, installation method, etc. of the optical elements 31a1, ... Are design matters and are appropriately determined according to the optical paths taken by the optical signals R, R ,.

The light guide plate 3a is different from the electric component boards 2a and 2b.
It is attached by means of a screw, an adhesive or the like so as to be sandwiched between the electric component boards 2a and 2b. At this time, it is possible to efficiently inject and emit the signal light R between the electric component board 2a and the light guide plate 3a and between the light guide plate 3a and the electric component board 2b and to radiate electronic components on the electric component boards 2a and 2b. Spacers 23, 23, ... Are inserted so that a certain distance is provided.

Next, the information transmission in the above-mentioned optical mounting board 1 will be described. The optical signal R emitted from the IC 21a with the light emitting terminal toward the light guide plate 3a is the IC 2 with the light emitting terminal.
The light passes through a hole 24a1 formed at a position overlapping with the light emitting portion of 1a and enters the light guide plate 3a substantially vertically. The optical signal R incident on the light guide plate 3a is transmitted by the optical element 31a1 to the optical element 31a2.
The light is totally reflected toward the side and proceeds in the light guide plate 3a. The optical signal R is totally reflected toward the electrical component substrate 2b side by the optical element 31a2 installed at a position overlapping with the light receiving portion of the IC 22a with the light receiving terminal, and is emitted from the light guide plate 3a. The optical signal R emitted from the light guide plate 3a passes through a hole 24b1 formed in a position overlapping with the light receiving portion of the IC 22a with a light receiving terminal and is received by the IC 22a with a light receiving terminal.

In this way, the optical mounting board 1 is mounted on the electrical component board 2a,
If the light guide plate 3a, which is an optical data bus, is sandwiched by 2b, electronic components such as integrated circuits can be attached to both sides of the light guide plate 3a, so that only one side of the light guide plate 3a has an electrical component board. It is possible to manufacture an electronic device that transmits a large amount of information between substrates in a lightweight and small size as compared with the case where the device is attached. In addition, in the optical mounting board 1 according to the present invention, most of the light guide plate 3a is covered with the electrical component boards 2a and 2b, so that the dust caused on the light guide plate 3a can be prevented from causing a failure in the optical data bus. You can Further, in the optical mounting board 1 according to the present invention, as compared with the case where a conductive wire or an optical fiber is used for information transmission between the electric component boards 2a and 2b,
Since the steps required for connecting the electric component boards 2a and 2b can be reduced, the electronic device can be manufactured more simply and inexpensively.

The optical mounting board 1 according to this embodiment is not limited to the above. For example, as shown in FIG. 2, the optical mounting board 1 is provided with an IC 21a with a light emitting terminal on one surface,
Electrical equipment board 2a having IC 22a with light receiving terminals on the other surface
The light guide plates 3a and 3b are attached to both surfaces of the IC, the IC 21a with the light emitting terminal emits the optical signal R toward the light guide plate 3a side, and the IC 22a with the light receiving terminal receives the optical signal R emitted from the light guide plate 3b. It may be configured to.

In the embodiment shown in FIG. 2, the electrical equipment substrate 2a is
A hole 24a1 through which the optical signal R passes is formed. Here, the position where the hole 24a1 is formed is a design item, and is appropriately determined in consideration of the arrangement of electronic components and the like attached to both surfaces of the electrical component board 2a. Further, an optical element 31a1 is installed on the light guide plate 3a at a position overlapping the light emitting portion of the IC 21a with a light emitting terminal, and an IC 2 with a light receiving terminal is provided on the light guide plate 3b.
The optical element 31b2 is installed at a position overlapping the light receiving portion 2a. Furthermore, when the optical mounting board 1 of the light guide plate 3a and the light guide plate 3b is formed, it is located at a position overlapping the hole 24a1.
Optical elements 31a2 and 31b1 are installed, respectively. Also in this embodiment, the IC 21a with the light emitting terminal and the IC 22a with the light receiving terminal are installed at positions not overlapping with each other.

In the embodiment shown in FIG. 2, the information transmission between the one surface and the other surface of the electrical equipment substrate 2a is performed by the light guide plates 3a and 3b.
By transmitting the optical signal R via the. IC with light emitting terminal
The optical signal R emitted from 21a enters the light guide plate 3a, is totally reflected by the optical element 31a1 toward the optical element 31a2 side, and travels in the light guide plate 3a. Further, the optical signal R is totally reflected by the optical element 31a2 toward the light guide plate 3b side, emitted from the light guide plate 3a, and penetrates the electrical component substrate 2a through the hole 24a1 to enter the light guide plate 3b. The optical signal R is generated by the optical element 31b1 provided at a position overlapping the hole 24a1.
The light is totally reflected toward the second side and travels inside the light guide plate 3b. Further, the optical signal R is totally reflected toward the IC22a with the light receiving terminal by the optical element 31b2 provided at a position overlapping with the light receiving portion of the IC22a with the light receiving terminal, emitted from the light guide plate 3b, and received by the IC22a with the light receiving terminal. .

When the optical mounting board 1 is constructed as shown in FIG. 2, the electronic mounting board 2a can be formed with high density by mounting electronic parts on both surfaces of the electric mounting board 2a, and the optical mounting board 1 can be formed with high density. it can. Therefore, this optical mounting board 1
It is possible to fabricate an electronic device equipped with a light-weight, small-sized and inexpensive device.

Further, the optical mounting board 1 according to the present embodiment is
.. and two or more light guide plates 3a, 3b, ... Are provided, and these electric component boards 2a, 2b, ... And light guide plates 3a, 3b ,. Good. For example, as shown in FIG. 3, the optical mounting board 1
Alternatively, the three electrical component boards 2a, 2b, and 2c and the three light guide plates 3a, 3b, and 3c may be alternately stacked with the spacers 23 interposed therebetween and attached to each other.

The electrical component substrate 2a of the optical mounting substrate 1 according to the embodiment shown in FIG. 3 is formed at a position overlapping the light emitting terminal IC 21a for emitting the optical signal R toward the light guide plate 3a and the light emitting portion of the light emitting terminal IC 21a. The hole 24a1 is provided. The light guide plate 3a is provided on the electronic component substrate 2a with a light emitting terminal IC2.
IC 21a with light emitting terminal attached to the side opposite to 1a
Optical element 31a1 installed at a position overlapping the light emitting portion of
And an optical element 31a2 installed at a position overlapping holes 24b2 and 24c3 described later.

The electric component board 2b is attached to the light guide plate 3a on the side opposite to the electric component board 2a. Electrical board 2b
Is attached to the surface on the side of the light guide plate 3a and has an IC 21b with a light emitting terminal for emitting an optical signal R toward the side of the light guide plate 3b, and a hole 24b1 formed at a position overlapping the light emitting portion of the IC 21b with a light emitting terminal, And a hole 24b2. Here, the drilling position of the hole 24b2 is appropriately determined in consideration of overlapping with a hole 24c3 described later and the arrangement of electronic components and the like mounted on the electrical component board 2b. The light guide plate 3b is attached to the opposite side of the electric component board 2b from the light guide plate 3a,
An optical element 31b1 installed at a position overlapping with a light emitting portion of an IC 21b with a light emitting terminal provided on the electrical board 2b;
An optical element 31b2 provided at a position overlapping a hole 24c2 described later is provided.

The electric component board 2c is attached to the light guide plate 3b on the side opposite to the electric component board 2b. The electrical component substrate 2c is installed on the light guide plate 3b side and includes an IC 22a with a light receiving terminal and an IC 22b with a light receiving terminal for receiving the optical signals R, R emitted from the light guide plate 3b. Further, the electrical component board 2c has a hole 24c1, a hole 24c2, and a hole 24c3 which are formed at a position overlapping with the light receiving portion of the IC 22b with a light receiving terminal.
And a hole 24c4 formed at a position overlapping the light receiving portion of the IC 22a with a light receiving terminal. The position where the hole 24c2 is formed is appropriately determined in consideration of the arrangement of electronic components and the like attached to the electrical component board 2c. Further, the position of the hole 24c3 to be formed is appropriately determined in consideration of the fact that it overlaps with the hole 24b2 described above and the arrangement of electronic components and the like attached to the electrical component board 2c.

The light guide plate 3c is mounted on the side opposite to the light guide plate 3b with respect to the electrical equipment substrate 2c. The light guide plate 3c is
The optical element 31c1 installed at a position overlapping the light receiving portion of the IC 22a with a light receiving terminal provided on the electrical component board 21c, and the optical element 31 installed at a position overlapping the hole 24c2 described above.
c2, an optical element 31c3 installed at a position overlapping the holes 24b2 and 24c3 described above, and an optical element 31c4 installed at a position overlapping the light receiving portion of the IC 22a with a light receiving terminal provided on the electrical component board 21c. There is.

Information transmission in the optical mounting board 1 of the embodiment shown in FIG. 3 will be described. The optical signal R emitted from the IC 21a with a light emitting terminal provided on the electrical component board 2a is provided with a light receiving terminal provided on the electrical component substrate 2c that is located away from the electrical component substrate 2a via the light guide plates 3a, 3b, 3c. IC2
The light is received by 2a.

The optical signal R emitted from the IC 21a with the light emitting terminal enters the light guide plate 3a through the hole 24a1, is totally reflected by the optical element 31a1 toward the optical element 31a2 side, and travels inside the light guide plate 3a. Further, the optical signal R is the optical element 31a2.
Then, the light is totally reflected toward the light guide plate 3c, emitted from the light guide plate 3a, penetrates the electrical equipment substrate 2b through the hole 24b2, enters the light guide plate 3b, and penetrates the light guide plate 3b almost vertically.
At c3, it penetrates the electrical equipment substrate 2c and enters the light guide plate 3c.
The optical signal R incident on the light guide plate 3c is totally reflected by the optical element 31c3 toward the optical element 31c4 side and travels inside the light guide plate 3c, and is further totally reflected by the optical element 31c4 toward the IC22a side with the light receiving terminal. It is emitted from the light plate 3c. Light guide plate 3
The optical signal R emitted from c passes through the hole 24c4 and is received by the IC 22a with a light receiving terminal.

Further, in the optical mounting board 1 shown in FIG. 3, the transmission of the optical signal R between the IC 21b with the light emitting terminal and the IC 22b with the light receiving terminal mounted on the electrical boards 2b and 2c which are close to each other is performed by the light guide plates 3b and 3c. Through. At this time, the optical signal R is transmitted through the hole 24b1, the optical element 31b1, and the optical element 3
1b2, hole 24c2, optical element 31c2, optical element 31
c1 and the hole 24c1 are transmitted.

In the embodiment shown in FIG. 3, the optical signal R is transmitted from the above-mentioned IC 21a with the light emitting terminal toward the IC 22a with the light receiving terminal.
Information can be transmitted between distant electric component boards, as in the case of transmitting a plurality of electric component boards 2a,
A plurality of optical signals R, R, ... Can be transmitted between 2b ,. Therefore, it is not necessary to connect the boards by conductors or optical fibers for the number of signals transmitted between the boards as in the past, so that an electronic device for transmitting a large amount of information between the boards can be easily and inexpensively manufactured. At the same time, it becomes easy to reduce the weight and size of this electronic device.

(Second Embodiment) Next, with reference to FIG. 4, an optical mounting board 1 according to a second embodiment of the present invention will be described. In each of the embodiments described below, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 4, the optical mounting substrate 1 according to the second embodiment is composed of an electrical component substrate 2a having electronic components such as integrated circuits on both sides, and a light guide plate 3a. The electrical board 2a is attached to the surface on the light guide plate 3a side, and the IC 2 with a light emitting terminal that emits the optical signal R toward the light guide plate 3a side.
1a is attached to the surface opposite to the light guide plate 3a, and is formed at a position overlapping with the light receiving terminal IC22a for receiving the optical signal R emitted from the light guide plate 3a and the light receiving portion of the light receiving terminal IC22a. And holes 24a1.

The light guide plate 3a includes an optical element 31a1 installed at a position overlapping the light emitting part of the IC 21a with a light emitting terminal and an optical element 31a2 installed at a position overlapping the light receiving part of the IC 22a with a light receiving terminal.

Next, transmission of the optical signal R in the optical mounting board 1 according to the second embodiment will be described. With light emitting terminal I
The optical signal R emitted from C21a enters the light guide plate 3a, is totally reflected by the optical element 31a1 toward the optical element 31a2, and travels inside the light guide plate 3a. Further, the optical signal R is totally reflected by the optical element 31a2 toward the electrical component substrate 2a and emitted from the light guide plate 3a toward the electrical component substrate 2a side. The optical signal R emitted from the light guide plate 3a passes through the hole 24a2 and is received by the IC 22a with the light receiving terminal.

According to the optical mounting board 1 of the second embodiment, it is not necessary to provide wiring for information transmission on the electric component board 2a, so that the electric component board 2a can be formed with high density. As a result, the electrical component board 2a can be formed with high density, and the optical mounting board 1 can be manufactured in a lighter weight, smaller size, and cheaper.

The optical mounting board 1 according to this embodiment is not limited to the above. The IC 22a with the light receiving terminal may be attached to the light guide plate 3a side of the electrical component substrate 2a, and the IC 21a with the light emitting terminal may be attached to the side opposite to the light guide plate 3a, or both the light emitting section and the light receiving section are attached to the integrated circuit section. Other electronic components may be attached to both surfaces of the electrical component board 2a.

(Third Embodiment) A third embodiment will be described with reference to FIG.
The configuration of the optical mounting board 1 according to the embodiment will be described. The optical mounting board according to the present embodiment includes two electrical component boards 2a and 2b arranged substantially in the same plane, and these electrical component boards 2
and a light guide plate 3a connected to the electrical equipment substrates 2a and 2b in a form of bridging a and 2b.

An IC 21a with a light emitting terminal for emitting an optical signal R toward the light guide plate 3a and a hole 24a formed in a position overlapping the light emitting portion of the IC 21a with a light emitting terminal are formed in the electrical equipment substrate 2a.
1 and are provided. Further, the electrical component board 2b has an IC with a light receiving terminal for receiving the optical signal R emitted from the light guide plate 3a.
22a and a hole 24b1 formed at a position overlapping the light receiving portion of the IC 22a with a light receiving terminal. Further, the IC 21a with the light emitting terminal and the IC 21a with the light emitting terminal are attached to the surfaces of the electrical component boards 2a and 2b opposite to the light guide plate 3a.

The light guide plate 3a is attached to the electric component boards 2a and 2b in a form of bridging the electric component boards 2a and 2b. The light guide plate 3a includes an optical element 31a1 installed at a position overlapping the light emitting part of the IC 21a with a light emitting terminal, and an optical element 31a2 installed at a position overlapping the light receiving part of the IC 22a with a light receiving terminal.

Next, transmission of the optical signal R in the optical mounting board 1 according to the third embodiment will be described. With light emitting terminal I
The optical signal R emitted from C21a passes through the hole 24a1,
The light enters the light guide plate 3a substantially vertically, is totally reflected by the optical element 31a1 toward the optical element 31a2, and travels through the light guide plate 3a. Further, the optical signal R is transmitted by the optical element 31a2 to the electrical board 2b.
The light is totally reflected toward the side and emitted from the light guide plate 3a.
The light passes through 1 and is received by the IC 22b with a light receiving terminal.

In this way, the electric component boards 2a and 2b are connected to the light guide plate 3
The light guide plate 3a bridges the electrical equipment substrates 2a, 2
By transmitting information between b, the electrical component boards 2a, 2
A large amount of information can be transmitted without connecting b with a conductor or an optical fiber. Therefore, in the optical mounting board 1 according to the present embodiment, it is possible to easily and inexpensively manufacture an electronic device that transmits a large amount of information between the substrates, and to reduce the size and weight of the electronic device.

The optical mounting board 1 according to the present embodiment is
It is not limited to that shown in FIG. For example, as shown in FIG. 6, an electric component board 2a having an IC 21a with a light emitting terminal and having a light guide plate 3a attached thereto, and an electric component board 2b having an IC 22a having a light receiving terminal and having a light guide plate 3c attached thereto are provided as a light guide plate. The form may be crosslinked at 3b. At this time, the optical signal R emitted by the IC 21a with the light emitting terminal is transmitted to the light guide plates 3a, 3
The signals b, 3c are sequentially transmitted and received by the IC 22a with a light receiving terminal.

Further, as shown in FIG. 7, the electrical equipment substrate 2a having the IC 21a with a light emitting terminal is attached to one surface of the light guide plate 3a, and the IC 2 with a light receiving terminal is attached to the other surface of the light guide plate 3a.
The electrical equipment substrate 2b provided with 2a may be attached. The structure shown in FIG. 7 is basically similar to the structure shown in FIG. 1, but the two electrical component boards 2a, 2b are
The positions of are shifted from each other so that they do not completely overlap.

The number of substrates mounted on the light guide plate 3a is not limited to two, and three or more electrical component substrates 2a, 2b, ...
However, the light guide plate 3a may be attached so as to be crosslinked.

Further, the light guide plate 3a to which the electric component boards 2a and 2b are attached is not limited to a flat plate. The optical mounting board 1 according to the present embodiment may have a structure in which the light guide plate 3a is bent at a bridge portion between the electric component board 2a and the electric component board 2b installed at different angles as shown in FIGS. 8 and 9. . At this time, in this bridge portion, the optical signal R transmitted in the light guide plate 3a is totally reflected at the boundary surface between the light guide plate 3a and the outside.
For example, the bridging portion may have an arcuate cross section as shown in FIG. 8, or the bridging portion may be an inclined surface having an appropriate angle as shown in FIG. Furthermore, FIG. 8 and FIG.
Also in the optical mounting board 1 according to the embodiment, the light guide plate 3a may have a structure in which three or more electric component boards 2a, 2b, ... Are bridged.

In this way, the light guide plate 3a is connected to the electrical equipment substrate 2a,
By forming the structure in which the bridge portion between 2b is bent, a large amount of information can be transmitted without connecting the electric component boards 2a, 2b, ... Attached at different angles with a conductor wire or an optical fiber. Further, it is possible to create the optical mounting board 1 corresponding to the shape of the electronic device body (case or the like).

Further, the electric component boards 2a and 2b are the light guide plates 3a.
It may be detachably attached to.
As a result, a function can be easily added to the electronic device including the electrical component board 1, and the electronic device can be easily disassembled.

Further, as shown in FIG. 10, in the optical mounting board 1 having a structure in which the electrical equipment substrate 2b is detachably attached to the light guide plate 3a, the IC 2 with the light emitting terminal is provided.
Only the electrical component substrate 2a provided with 1a is attached to the light guide plate 3a, and the optical signal R emitted by the IC 21a with the light emitting terminal is emitted.
Electrical board 2b provided with an IC 22a with a light receiving terminal for receiving light
In the case where is not attached to the light guide plate 3a, the light emitting terminal-equipped IC 21a may have a function of not emitting the optical signal R to the light emitting terminal-equipped IC 21a.

Whether or not the electrical component board 2b is attached to the light guide plate 3a is detected, for example, when the electrical component board 2b is connected to the light guide plate 3a, the electrical component board 2a and the electrical component board 2b are electrically connected. It may be performed in the form of being performed. In this case, the IC 21a with the light-emitting terminal outputs the optical signal R only when the electric signal from the electric component board 2b is detected.
Is to be emitted.

As a detection method other than the above-mentioned method,
There is a method in which the IC 21a with a light emitting terminal and the IC 22a with a light receiving terminal are provided with both functions of emitting an optical signal and receiving an optical signal, and the IC 21a with a light emitting terminal and the IC 22a with a light receiving terminal communicate with each other. In this case, when the IC 21a with the light emitting terminal emits the optical signal R, the response optical signal R'is emitted from the IC 22a with the light receiving terminal, and the IC 21a with the light emitting terminal continues only when it detects the response optical signal R '. Then, the optical signal R is emitted.

By doing so, in the state where the electrical equipment substrate 2b is not attached to the light guide plate 3a, the light emitting terminal-equipped I
C21a does not emit an unnecessary optical signal. As a result, it is possible to prevent a person such as a user of the electronic device from hitting the unnecessary optical signal, and the electronic device can be used safely.

In the electrical component board 1 according to the present invention, the conditions under which the ICs 21a with light emitting terminals, ... Do not emit the optical signal R are not limited to the above. For example, in FIG. 10, when the electrical equipment substrate 2b is attached to the light guide plate 3a, but the electrical equipment substrate 2b is not attached with the light receiving terminal IC 22a for receiving the optical signal R transmitted from the light emitting terminal IC 21a. The light emitting terminal-equipped IC 21a may not emit the optical signal R.

(Fourth Embodiment) An optical mounting board 1 according to a fourth embodiment will be described with reference to FIG. Fourth
The optical mounting board 1 according to the embodiment is the main optical mounting board 11
And optical mounting modules 4, 4, ....

The main optical mounting board 11 of the optical mounting board 1 according to the fourth embodiment is composed of an electrical component board 2a and a light guide plate 3a. The electrical equipment substrate 2a includes a light emitting terminal-equipped IC 21a that emits an optical signal R toward the light guide plate 3a, and a light emitting terminal-equipped IC 21a.
A hole 24a1 formed at a position overlapping the light emitting portion of 21a.
, And slots 25, 25, ... For detachably mounting the optical mounting modules 4, 4, ... On the main optoelectronic substrate 11.
Connectors 26, 26 for electrically connecting the electrical component board 2a and the electrical component board 5 provided in the optical mounting module 4,
... and is configured.

The light guide plate 3a comprises an optical element 32, optical elements 33, 33, ... And optical elements 31a1, 31a ,. The optical element 32 is an IC2 with a light emitting terminal.
An IC with a light emitting terminal installed at a position overlapping the light emitting portion of 1a
The optical signal R emitted by 21a is branched into, for example, three directions and reflected to appropriately branch the optical signal R into a plurality of optical signals R, R, .... The optical element 33 is branched by the optical element 32, totally reflects the optical signal R that has arrived, and the optical element 31a
Transmit to 1. The mounting positions and angles of the optical elements 33, 33, ... Are the same optical paths for the optical signals R, R, ... Branched by the optical element 32 and transmitted to the ICs 52, 52 ,. It is decided to reach the respective ICs 52, 52, ... With a light receiving terminal through the length. Since the optical element 31a1 reflects the optical signal R transmitted from the optical element 33 toward the light guide plate 6 described later, the optical element 31a1 is installed at a position overlapping the slot 25 provided in the electrical component substrate 2a.

Further, the optical mounting module 4 according to the fourth embodiment comprises an electrical equipment substrate 5 and a light guide plate 6. The electrical equipment substrate 5 is provided at a position where it overlaps with the light receiving portion of the IC 52 with a light receiving terminal because the IC 52 with a light receiving terminal for receiving the optical signal R emitted from the light guide plate 6 and the optical signal R received by this IC 52 with a light receiving terminal are passed. And a terminal 55 for electrically connecting the electrical component board 2 and the electrical component board 5.

The light guide plate 6 is, for example, a flat plate having a high light-transmitting property and a high refractive index, and is provided with an optical element 61. The optical element 61 is installed at a position overlapping with the optical element 31a1 installed on the light guide plate 3a and the light receiving part of the IC 52 with light receiving terminal, and is an optical signal incident from the end of the light guide plate 6 inserted into the slot of the electrical component substrate 2a. The R is reflected and transmitted to the IC 52 with a light receiving terminal. The end of the light guide plate 6 facing the light guide plate 3a is formed in a substantially flat shape so that the optical signal R emitted from the light guide plate 3a can enter the light guide plate 3a.
It is installed so as to be substantially parallel to a.

The optical mounting module 4 is formed by connecting the above-mentioned electrical equipment substrate 5 and light guide plate 6 with a screw, an adhesive or the like. At this time, between the electrical equipment substrate 5 and the light guide plate 6,
A spacer 5 for providing an interval such that the signal light R can be efficiently incident and emitted and the electronic components on the electrical component board 5 can be radiated.
3, 53, ... Are inserted.

Next, the connection between the main optical mounting board 11 and the optical mounting modules 4, 4, ... Is described. The optical mounting module 4 is detachably connected to the optical mounting substrate 1 by inserting the light guide plate 6 into the slot 25 in the direction of the arrow in the drawing. By this connection, the light guide plate 3a and the light guide plate 6,
, ... Form an optical data bus. At the same time, by inserting the terminal 55 into the connector 26, the electrical component board 2
a is also electrically connected to the electrical component substrate 5 to supply drive power for the electronic components provided on the electrical component substrate 5, or the electrical component substrate 2
It is possible to transmit an amount of electric signals between a and the electric component board 5 without using an optical data bus.

Further, information transmission by the optical data bus provided in the main optical mounting board 11 and the optical mounting modules 4, 4, ... Connected as described above will be described. The optical signal R emitted from the IC 21a with the light emitting terminal passes through the hole 24a1 and enters the light guide plate 3a substantially vertically. The incident optical signal R is diffused and reflected by the optical element 32 and branched into a plurality of optical signals R, R, ... And the optical elements 33, 3 inside the light guide plate 3a.
3. Go to the side. The branched optical signal R is totally reflected by the optical element 33 toward the optical element 31a1 and travels inside the light guide plate 3a. Further, the optical signal R is totally reflected by the optical element 31a1 toward the light guide plate 6 and is emitted from the light guide plate 3a to guide the light guide plates 6, 6 ,.
It is incident on the edge from. The optical signal R incident on the light guide plate 6 is reflected by the optical element 61 toward the IC 54 with the light receiving terminal, passes through the hole 54, and is received by the IC 52 with the light receiving terminal. Also,
The optical paths R, R, ... Branched by the optical element 32 until the optical signals R, R, ... reach the ICs 52, 52, ... With light receiving terminals have the same value for the above-mentioned reason. , 52, ... Are synchronized with the optical signals R, R ,. In this way, information can be transmitted from the electric component board 2a of the optical mount substrate 1 to the electric component boards 5, 5, ... Of the optical mount modules 4, 4 ,.

As described above, in the present embodiment, the optical mounting modules 4, 4, ... Can be easily attached / detached to / from the main optical mounting substrate 11 both electrically and optically. As a result, in an electronic device equipped with the main optical mounting board 11, it becomes extremely easy to expand the functions by the function expansion board having the optical data bus and to apply the memory module having the optical data bus.

Further, in the optical mounting board 1 according to the present embodiment, the IC 21a with a light emitting terminal and the ICs 5 with a plurality of light receiving terminals are provided.
By making the optical path lengths between 2, 52, ...
The optical signals R, R, ... Received by the ICs 52, 52, ... With light receiving terminals can be synchronized, and the optical signals can be transmitted at a higher speed.

The main optical mounting board 11 and the optical mounting modules 4, 4, ... Of the optical mounting board 1 according to this embodiment are not limited to the above-mentioned examples. For example, the optical mounting module 4 may be provided with an IC with a light emitting terminal, and information may be transmitted from the optical mounting module 4 to the optical mounting board 1. Between the main optical mounting board 11 and the optical mounting module 4. The information may be mutually transmitted by.

The electric component boards 2a, 2b, ... Provided in the electric component board 1 according to the present invention may be electrically connected to each other. As a result, it is possible to supply electric power to the electrical component boards 2a, 2b, ... And to transmit an amount of data that does not require the use of an optical data bus as an electrical signal.

Further, the optical mounting board 1 and the optical mounting module 4 according to the present invention have the above-described electrical component boards 2a, 2b, ...
Are not limited to those in which the light guide plates 3a, 3b, ... Are attached to each other at appropriate intervals, and the electrical component boards 2a, 2b ,.
The light guide plates 3a, 3b, ... May be in close contact with each other.

Further, the light emitting portion and the light receiving portion according to the present invention are not limited to those integrally formed with the integrated circuit portion, and those different from the integrated circuit portion may be electrically connected to electrical parts such as an integrated circuit. You may connect to.

The means for penetrating the electrical signal R through the electrical component boards 2a, 2b, ... Is not limited to the holes 24a1, .. For example, the portions through which the optical signal R of the electrical component boards 2a, 2b, ... Members may be applied. By this,
It is possible to more effectively prevent dust from adhering to the light guide plates 3a, 3b, ....

[0087]

As described above, according to the present invention,
It is possible to form the optical mounting board for transmitting a large amount of information between the electric equipment boards or within the electric equipment board with high density and small size. Therefore, it is possible to form a lightweight and small-sized electronic device that transmits a large amount of information between or within the electrical component boards.

Further, by covering the light incident portion and the light emitting portion of the light guide plate with the electrical equipment substrate, it is possible to reduce the failure of the optical mounting substrate due to the attachment of dust to the light guide plate.

Further, in the case of transmitting information between two or more electric component boards, when assembling an electronic device equipped with these electric component boards, the step of connecting the electric component boards with a conductor wire or an optical fiber is omitted. Therefore, this electronic device can be easily and inexpensively manufactured.

Further, according to the seventh aspect, the light guide plate bridging the two or more electric component boards has a bent structure, so that the electric component boards can be formed in accordance with the shape of the electronic apparatus main body.

According to the eighth aspect of the present invention, by attaching the electrical mounting board of the optical mounting board to the light guide plate in a detachable manner, it is possible to easily add a function to the electronic equipment equipped with the optical mounting board, The equipment can be easily disassembled.

Further, according to the present invention, since the light emitting section provided in the optical mounting substrate does not emit the unnecessary optical signal, the human being such as the user of the electronic device receives the unnecessary optical signal. It is prevented from hitting. Therefore, safety is ensured during use of this electronic device.

According to the tenth aspect of the present invention, the optical mounting module is detachably connected to the optical mounting board, so that in an electronic device equipped with this optical mounting board, function expansion by means of a function expansion board equipped with an optical data bus is possible. Therefore, the application of the memory module having the optical data bus becomes extremely easy.

Further, according to the eleventh aspect, by synchronizing the optical path lengths of the light emitting portion on the optical mounting board and the plurality of ICs with light receiving terminals on the optical mounting module, the information transmitted to these optical mounting modules is synchronized. Can take

[Brief description of drawings]

FIG. 1 is a side sectional view of an optical mounting board 1 according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of an optical mounting board 1 of another example of the first embodiment.

FIG. 3 is a side sectional view of an optical mounting board 1 according to another example of the first embodiment.

FIG. 4 is a side sectional view of an optical mounting board 1 according to a second embodiment of the present invention.

FIG. 5 is a side sectional view of an optical mounting board 1 according to a third embodiment of the present invention.

FIG. 6 is a side sectional view of an optical mounting board 1 of another example of the third embodiment.

FIG. 7 is a side sectional view of an optical mounting board 1 of another example of the third embodiment.

FIG. 8 is a side sectional view of an optical mounting board 1 of another example of the third embodiment.

FIG. 9 is a side sectional view of an optical mounting board 1 of another example of the third embodiment.

FIG. 10 is an optical mounting board 1 of another example of the third embodiment.
FIG.

FIG. 11 is an optical mounting board 1 according to a fourth embodiment of the present invention.
3 is a side sectional view of the optical mounting modules 4, 4, ... And a bottom view of a main part of the optical mounting board 1. FIG.

[Explanation of symbols]

1 Optical mounting board 2a, 2b, 2c, 5 Electrical board 3a, 3b, 3c, 6 light guide plate 4 Optical mounting module 11 Main optical mounting board 21a, 21b IC with light emitting terminal 22a, 22b, 52 IC with light receiving terminal

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H037 BA02 BA11 CA37 DA06 DA39                 2H047 KA02 LA09 MA07                 5F041 AA47 CB33 DA35 EE25                 5F073 AB25 AB29 EA27 EA29 FA30                 5F088 AA01 BA15 BA16 EA08 JA03                       JA14 KA10

Claims (11)

[Claims] 1. A light emitting section for converting an electric signal into an optical signal and emitting the optical signal in an optical mounting board which is attached to an electronic device main body and carries out information transmission between a plurality of electronic components or electronic circuits by the optical signal. And an electric component board having both or one of a light receiving unit for receiving an optical signal and converting the optical signal into an electric signal; and a light-transmitting material, which is attached to the electric component board, A light guide plate for transmitting an optical signal, and the electric component board and the light guide plate,
An optical mounting board, characterized in that they are alternately stacked and connected in the thickness direction. 2. The optical mounting board according to claim 1, wherein one of the two electrical component boards mounted on both surfaces of one light guide plate is provided with at least a light emitting portion, and the other is provided. At least the light receiving portion is provided on the electrical board, the light emitting portion and the light receiving portion are arranged at positions not overlapping each other, and an optical signal emitted from the light emitting portion is transmitted to the light receiving portion via the light guide plate. Optically mounted substrate characterized by being transmitted. 3. The optical mounting board according to claim 1, wherein at least a light emitting portion is provided on one surface of one of the electrical component boards,
At least the light receiving portion is provided on the other surface, the light emitting portion and the light receiving portion are arranged at positions not overlapping each other, and the electrical component substrate is sandwiched between the two light guide plates. The emitted optical signal is emitted from the light guide plate on the light emitting unit side into the air, penetrates the electrical equipment substrate, enters the light guide plate on the light receiving unit side, and then is received by the light receiving unit. Optical mounting board. 4. An optical mounting board which is attached to an electronic equipment main body and carries out information transmission between a plurality of electronic parts or electronic circuits by optical signals, which emits the optical signals by converting the electrical signals into the optical signals. And a light receiving plate for receiving an optical signal and converting the optical signal into an electric signal, and a light guide plate made of a material having a light-transmitting property and attached to the electric device substrate for transmitting the optical signal. And an optical mounting board provided with a light emitting section on one surface of the electrical board and a light receiving section for receiving an optical signal emitted by the light emitting section on the other surface. . 5. The optical mounting board according to claim 4, wherein the light emitting unit and the light receiving unit are arranged at positions not overlapping each other, and an optical signal emitted from the light emitting unit is passed through the light guide plate. The optical mounting board, wherein the optical signal is transmitted to the light receiving unit, and the optical signal penetrates through the electrical equipment substrate during the transmission process. 6. A light emitting section for converting an electric signal into an optical signal and emitting the optical signal in an optical mounting board which is mounted on an electronic equipment body and transmits information between a plurality of electronic parts or electronic circuits by an optical signal. And an electric component board having both or one of a light receiving unit for receiving an optical signal and converting the optical signal into an electric signal; and a light-transmitting material, which is attached to the electric component board, A light guide plate for transmitting an optical signal, and one light guide plate has at least 2
An optical mounting board, characterized in that at least one electrical board is bridged and connected to the electrical board, and an optical signal is transmitted between the different electrical boards by the light guide plate. 7. The optical mounting board according to claim 6, wherein the two or more electric component boards are arranged at different angles from each other, and the light guide plate is bent at a bridge portion between the two electric component boards. An optical mounting substrate having a shape. 8. The optical mounting board according to claim 6 or 7, wherein at least one or more of the electrical component boards among the at least two or more electrical component boards to which the light guide plate is connected are detachably attached to the conductive substrate. An optical mounting board, which is connected to an optical plate. 9. The optical mounting board according to claim 8, wherein at least one of the electrical component boards connected to the light guide plate is provided on another electrical component board detachably connected to the light guide plate. And a light emitting portion that emits an optical signal toward the light receiving portion, and the light emitting portion does not emit an optical signal when the other electrical substrate is not connected to the light guide plate. Mounting board. 10. An optical mounting board which is attached to an electronic equipment main body and carries out information transmission between a plurality of electronic components or electronic circuits by an optical signal, wherein the optical mounting board carries out information transmission between a plurality of electronic components or electronic circuits. A main optical mounting board for performing an optical signal; and an optical mounting module detachably connected to the main optical mounting board for transmitting information between a plurality of electronic components or electronic circuits by an optical signal. An optical mounting substrate and the optical mounting module, a light emitting unit that converts an electrical signal into an optical signal and emits the optical signal,
An optical component board having both or one of a light receiving unit for receiving an optical signal and converting the optical signal into an electric signal; and a light-transmitting material, which is attached to the electrical component board, A light guide plate for transmitting the light, and an electrical component board provided on the main optical mount board when the main optical mount board and the optical mount module are connected, and an electrical component provided on the optical mount module. Optical mounting, wherein the substrate is electrically connected, and the light guide plate provided on the main optical mounting substrate and the light guide plate provided on the optical mounting module are optically connected. substrate. 11. The optical mounting board according to claim 10, wherein the two or more optical mounting modules connected to the optical mounting board from one light emitting portion provided on the main optical mounting board are provided. And / or one or both of the light emitting section and the light receiving section, and both or one of the light receiving section and the light emitting section provided in the two or more optical mounting modules connected to the main optical mounting board. A plurality of optical paths for transmitting an optical signal are provided between the optical mounting board and the optical path, and the optical path lengths of the optical paths are equal to each other.