JP2001074960A - Optical data bus and signal processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the variance in transmission efficiency caused by the positional relationship between a light emitting part and a light accepting part. SOLUTION: The signal light R emitted from the light emitting part 24A is diffused by a light diffusing part 28A and changed for its optical path in an optical path changing part 30A to propagate almost parallel to the boundary face L. The signal light R is transmitted through a core layer 16 and accepted at a specified angle on the light accepting face of each light accepting element. The signal light Q1 emitted from a light emitting part 24B is diffused by a light diffusing part 28B, changed into almost parallel to the boundary face L by an optical path changing part 30B and accepted at a specified angle by the accepting face of each light accepting element. The signal light Q2 is changed in the same way. Thus, the signal light always enters the each light accepting element at the same angle so that the variance in the transmission efficiency caused by the positional relationship between the light emitting part and the light accepting part can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical data bus for transmitting signal light and a signal processing device for performing signal processing including transmission and reception of data using the optical data bus.

[0002]

2. Description of the Related Art With the recent development of very large scale integrated circuits (VLSI), circuit functions of circuit boards (daughter boards) used in data processing systems have been greatly increased.
As the number of signal connections to each circuit board increases as circuit functions increase, the data bus board (motherboard) that connects each circuit board (daughter board) with a bus structure requires a large number of connectors and connection lines. Parallel architecture has been adopted.

[0003] Here, the operation speed of the parallel bus has been improved by promoting parallelization by increasing the number of connection lines and miniaturizing the connection lines. The processing speed of the system may be limited by the operating speed of the parallel bus. In addition, the problem of electromagnetic noise due to the increase in the density of parallel bus connection wiring is also a major constraint on improving the processing speed of the system.

In order to solve such a problem and improve the operation speed of the parallel bus, use of an in-system optical connection technique called optical interconnection has been studied.

[0005] The outline of the optical interconnection technology is described in "Seiji Uchida, 9th Circuit Packaging Academic Lecture Meeting 15C
01, pp. 201-202 "and" Hisami Tomimuro. Current Status and Trends of Optical Interconnection Technology, IEEE Tokyo
o Section Denshi Tokyo No.
33 pp. 81-86, 1994], various forms are proposed depending on the configuration of the system.

[0006] Among various types of optical interconnection technologies proposed in the past, Japanese Patent Application Laid-Open No. 2-41042 discloses an optical data transmission system using a high-speed, high-sensitivity light emitting / receiving device applied to a data bus. Examples are disclosed. Here, a light-emitting / light-receiving device is arranged on both front and back surfaces of each circuit board, and a loop between the circuit boards is formed by spatially coupling light-emitting / light-receiving devices on adjacent circuit boards incorporated in the system frame with light. Serial optical data buses for transmission have been proposed.

Here, a signal light sent from a certain circuit board is subjected to optical / electrical conversion on an adjacent circuit board, and is further subjected to electrical / optical conversion on that circuit board, and then to the next adjacent circuit board. The signal light is transmitted between all the circuit boards incorporated in the system frame while repeating the photoelectric conversion on each circuit board.

For this reason, the signal transmission speed depends on the light / electric conversion / electricity / electricity of the light receiving / light emitting device arranged on each circuit board.
It depends on the light conversion speed and at the same time is constrained. In addition, since data transmission between each circuit board uses optical coupling with a free space therebetween, optical alignment of light emitting / receiving devices arranged on both front and back surfaces of an adjacent circuit board is performed. All circuit boards must be optically coupled. Further, since the optical data transmission paths are coupled via a free space, interference (crosstalk) between adjacent optical data transmission paths occurs, and data transmission failure is expected. In addition, it is expected that data transmission failure occurs due to scattering of signal light due to an environment in the system frame, for example, dust or the like. Furthermore, since the circuit boards are arranged in series, if any one of the boards is removed, the connection is interrupted there, and an extra circuit board is required to compensate for the disconnection. That is, there is a problem that the circuit board cannot be freely inserted and removed, and the number of circuit boards is fixed.

On the other hand, a data transmission technique between circuit boards using a two-dimensional array device is disclosed in Japanese Patent Application Laid-Open No. 61-196.
No. 210 discloses this.

[0010] The technology disclosed herein includes a plate having two parallel surfaces and opposed to a light source, and a circuit between a circuit board and an optical path formed by a diffraction grating and a reflection element arranged on the plate surface. Are optically coupled.

In this method, there is a problem that light emitted from one point can be connected to only one fixed point, and it is not possible to connect all circuit boards comprehensively like an electric bus. In addition, an integrated complex optical system including a diffraction grating and a reflection element is required, and positioning is difficult.
There is a problem that interference (crosstalk) between adjacent optical data transmission paths occurs due to the displacement of the optical element, and data transmission failure is expected. Furthermore, since the connection information between the circuit boards is determined by the diffraction grating and the reflection element arranged on the plate surface, the circuit boards cannot be freely attached and detached, and there is a problem that the expandability is low.

Another technique for data transmission between circuit boards using a two-dimensional array device is disclosed in
No. 34415. The technology disclosed herein is a lens array in which a plurality of lenses having a negative curvature are formed on a surface of a transparent material having a higher refractive index than air, and a light emitted from the light source. An optical data bus composed of an optical system for allowing light to enter from the side surface of the lens array is described. In addition, a method using a region having a low refractive index or a hologram instead of a plurality of lenses having a negative curvature is also disclosed.

In this method, the light incident from the side surface is distributed on the surface from a plurality of lenses having the negative curvature, a low refractive index region instead of the plurality of lenses having a negative refractive index, or a hologram constituted portion, and the light is emitted. Used. Therefore, it is conceivable that the intensity of the output signal varies depending on the positional relationship between the incident position and a plurality of lenses, a region having a low refractive index instead of the lens, or the output position on the surface of the hologram. Also,
It is considered that the rate at which light incident from the side surface escapes from the opposite side surface is high, and the efficiency of light used for signal propagation is low. Further, since it is necessary to dispose a plurality of lenses having a negative curvature formed on the surface, a region having a low refractive index instead of the lens, and a position of the hologram, the circuit substrate is disposed. There are various problems that there is no degree of freedom and the expandability is low.

As means for solving these problems, JP-A-10-123350 and JP-A-10-20667 are disclosed.
No. 7 discloses a sheet-shaped optical data bus. This method diffuses and propagates the signal light incident on the common signal path, so that a plurality of circuit boards having light receiving and emitting parts can be securely optically coupled by simple mounting, and precise optical No alignment is required. In addition, the number of circuit boards and the mounting position can be freely changed, and a highly expandable and highly flexible system can be constructed. In addition, since the transmission path is used, it has an environment resistance against dust and the like, and has an advantage that it is resistant to a temperature change and the like because optical positioning is not required.

In the optical data buses disclosed in JP-A-10-123350 and JP-A-10-206677, light is diffused in all directions. It is released where there is no. Further, the optical data bus disclosed in this publication does not describe the relative positional relationship between the signal light incident portion and the signal light emitting portion, and collects the signal light emitted to a place where there is no light receiving element. There is no description that light is transmitted to improve the transmission efficiency of signal light. Therefore, the light intensity at the light receiving section is
It becomes very weak, and there is a problem in high speed and low power consumption.

In order to solve this problem, as disclosed in Japanese Patent Application Laid-Open Nos. H10-62657 and H11-142691, a signal provided on an arbitrary side of a sheet-shaped optical data bus is disclosed. The signal light incident by the light incident part is diffused in the light diffusion part corresponding to each incident part,
A method has been proposed in which the signal propagates to a signal light emitting unit disposed opposite to an optical transmission layer formed by forming an optical optical data bus. In this method, the signal light is transmitted through a sheet-like optical transmission line by controlling the diffusion distribution of light in a light diffusion section corresponding to each incident section by arranging the signal light incidence section and the signal light emission section. Since light can be effectively guided in the direction of the light emitting portion, the light transmission efficiency of the sheet-shaped optical data bus is improved, and high speed and low power consumption can be achieved.

[0017]

However, the following new problem arises even if a method of controlling the diffusion distribution of light in accordance with the arrangement of the signal light incidence portion and the signal light emission portion is used.

That is, as shown in FIG. 6, the light receiving element 60 disposed in the signal light emitting section receives a signal light P from a light emitting element 62 disposed in a plurality of signal light incident sections in response to a bus control signal. However, since the physical relative positions of the plurality of signal light incident portions with respect to the signal light emitting portion are different, the signal light P is at a different angle with respect to the light receiving surface of the light receiving element 60 arranged in the signal light emitting portion. Incident. This light receiving element 60 includes
Although a condenser lens 64 for efficiently condensing the signal light P emitted from the signal light emitting section is provided, since the incident angle to the light receiving element 60 is different, the light collecting efficiency of the light receiving element 60 is reduced. A drop (blur) occurs, and the transmission efficiency varies depending on the positional relationship between the signal light incident portion and the signal light emitting portion.

As shown in FIG. 6, the light emitting element 62 and the light receiving element 60 are arranged to face each other with the optical bus main body 66 interposed therebetween. In addition, only transmission in the direction of arrow A in the figure can be performed between the light receiving elements 60 arranged on another side opposite to this one side. When the light-emitting / light-receiving elements are arranged in pairs on the other side opposite to one side of the optical bus main body 66 instead of the light-emitting element 62 and the light-receiving element 60, the direction of the arrow A in FIG. Can be transmitted in both directions.
6 cannot be transmitted between the light emitting element and the light receiving element arranged on one side.

Therefore, the present invention reduces the variation in transmission efficiency caused by the positional relationship between the light emitting unit and the light receiving unit, and reduces the variation in transmission efficiency regardless of the positional relationship between the light emitting unit and the light receiving unit. It is an object to provide an optical data bus capable of transmitting signal light and a signal processing device using the optical data bus.

[0021]

According to the first aspect of the present invention, there is provided an optical data bus in which a core layer and a cladding layer having a refractive index smaller than that of the core layer are alternately laminated, and signal light is transmitted in the core layer. An optical bus main body for transmission, a light diffusing portion formed on the cladding layer and diffusing the signal light incident from the center of the bottom surface of the optical bus main body, and a light diffusing portion formed on the boundary surface between the core layer and the cladding layer. And an optical path changing unit that transmits the signal light into the core layer by making the optical path of the signal light substantially parallel to the boundary surface.

According to this configuration, the signal light incident from the center of the bottom surface of the optical bus main body is diffused by the light diffusion portion formed in the cladding layer. The signal light diffused by the light diffusing unit is made substantially parallel to the boundary surface by an optical path changing unit formed on the boundary surface between the core layer and the cladding layer,
Transmit in the core layer.

For this reason, all the signal light incident on the optical bus main body is substantially parallel to the interface between the core layer and the cladding layer, so that the optical paths of the signal light transmitted through the core layer always have the same angle. Can be changed to

Further, the signal processing device according to claim 2 is
An optical bus main body for transmitting signal light in the core layer and a plurality of cladding layers having a refractive index smaller than the refractive index of the core layer alternately laminated, and a signal light incident on the center of the bottom surface of the optical bus main body. And a light diffusion portion formed on the cladding layer and diffusing the signal light incident from the center of the bottom surface of the optical bus body,
An optical path changing unit formed at an interface between the core layer and the cladding layer and transmitting the signal light into the core layer by making an optical path of the signal light diffused by the light diffusing unit substantially parallel to the interface; A light receiving unit disposed on the outer edge and receiving the signal light whose optical path has been changed by the optical path changing unit; a generating circuit including the light receiving unit and generating a signal to be carried by the signal light incident on the optical bus main body; and an optical bus main body A plurality of circuit boards on which at least one of a processing circuit that performs signal processing based on a signal carried by the signal light emitted from the core layer is mounted, and a signal generated by the generation circuit or a signal processed by the processing circuit And a transmission unit for transmitting the signal to the light emitting unit.

According to this configuration, the signal light emitted from the light emitting section enters the optical bus main body from the bottom center of the optical bus main body. This signal light is diffused by a light diffusion part formed in the cladding layer. Thereafter, the optical path of the signal light is made substantially parallel to the boundary surface between the core layer and the clad layer by the optical path changing unit, and is transmitted in the core layer. The signal light transmitted in the core layer always enters the light receiving unit at the same angle. When the signal light is received by the light receiving unit, a signal carried by the signal light incident on the optical bus body is generated by the generation circuit of the circuit board, or a signal carried by the signal light received by the light receiving element. Signal processing is performed based on Then, these signals are transmitted to the light emitting unit by the transmission means.

Therefore, in such a signal processing device, since the signal light always enters the light receiving element at the same angle,
Transmission and reception of signal light with little variation in signal strength between a plurality of circuit boards becomes possible, and there is no need to adjust the signal level between the circuit boards. Further, a light emitting element having a resistance amount can be used, and low power consumption can be realized.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical data bus and a signal processing device according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a signal processing device according to the present embodiment.

As shown in FIG. 1, the signal processing device 10
A disk-shaped optical data bus main body 12 having a diameter of 50 mm is provided. The optical data bus body 12 has a refractive index of 1.4.
9. a core layer 14 (light transmission layer) made of polymethyl methacrylate (PMMA) having a thickness of 1 mm and having high light transmittance;
The transparent medium 18 is formed by laminating nine layers of a clad layer 16 having a refractive index of 1.34 and a fluoropolymer material (for example, Cytop manufactured by Asahi Glass Co., Ltd.).

The optical data bus body 12 is connected to the main circuit board 2
0 (motherboard) by a base fixing portion (not shown).

The core layer 14 may be formed of a translucent plastic material such as polycarbonate (PC) or polystyrene (PS) instead of the PMMA. A fluorine-containing polymer material can be used.

Further, for the core layer 14, a quartz glass material can be used in addition to a plastic material. On the other hand, P ₂ O ₅ ,
It is also possible to use a quartz-based material whose refractive index is controlled using Al ₂ O ₃ , B ₂ O _3, or the like.

As shown in FIG. 2, a signal light incident portion is formed at the center of the bottom of the optical data bus main body 12. A surface-emitting type laser diode array 22 is embedded in the main circuit board 20 below the signal light incident portion.

The laser diode array 22 includes m × n or m × m (m and n are integers of 1 or more) light emitting units 2.
In the present embodiment, a total of nine light-emitting portions 24 arranged in three rows vertically and horizontally are two-dimensionally arranged.

As described above, by arranging the light emitting sections 24 in three rows each vertically and horizontally, the area occupied by the laser diode array 22 can be reduced as compared with a case where the light emitting sections 24 are arranged in a straight line, for example.

As shown in FIG. 3, a diffusing portion 26 is provided on each of the light-transmitting portions 24 of the laser diode array 22 and on the transparent medium 18 having a different layer.

The diffusion section 26 is composed of a transmission type diffusion layer 28 in which a silica-based white pigment is mixed into polyester, and a diffusion layer 2.
8 and an optical path changing portion 30 formed at a position facing each other with the core layer 14 on the upper side in the stacking direction.

As shown in FIG. 4, this optical path changing unit 30
Has an inclined surface 32 in which the cladding layer 16 is formed so as to protrude inside the core layer 14, and the center of the inclined surface 32 is
It is formed toward the side.

The inclined surface 32 constituting the optical path changing unit 30
Tangent S to the interface L between the core layer 14 and the cladding layer 16
Is formed in a shape in which α gradually increases from 20 degrees to 60 degrees toward the center of the optical path changing unit 30.

As shown in FIG. 1, a signal light emitting portion is formed at the peripheral portion of the optical data bus main body 12.
Eight sub-circuit boards 34 are arranged on the outer periphery of the signal light emitting section. A light receiving element 36 is mounted on a part of each sub-circuit board 34, and is optically coupled to the signal light emitting section of the optical data bus main body 12 via the light receiving element 36.

Each of the sub-circuit boards 34 has a generating circuit 44 for generating a signal to be carried by the signal light incident on the optical data bus main body 12, and a signal to be carried by the signal light received by the light receiving element group 36. And at least one of the processing circuits 46 is mounted.

Further, as shown in FIG.
Is provided with a first transmission line 38 for transmitting a signal generated by the generation circuit 44 of the sub-circuit board 34 to the light emitting unit 24. The transmission line 38 is electrically connected to each of the sub-circuit boards 34, and is also connected to a control chip 40 which controls the right to acquire the optical data bus main body 12. Further, a second transmission line 42 is connected from the control chip 40 to each light emitting unit 24.

The core layer 14 and the laser diode 22
The number of the light-emitting portions 24 is nine, but the number is not limited thereto. For example, two light beams having different light emission intensities and wavelengths may be multiplexed and transmitted in one core layer 14. There is a case where one light emitting unit 24 corresponds.

Next, the operation and effect of the signal processing device of the present embodiment will be described.

Of the nine light emitting units of the laser diode array 22 which are two-dimensionally arranged in three rows and three columns, as shown in FIGS. 3 and 4, the light emitting unit 24A located at the center is used for synchronization. A clock signal light R is transmitted. This signal light R is
The light is diffused by the light diffusing portion 28A formed in the lowermost clad layer 16. Then, the signal light R enters the lowermost core layer 18, and the optical path of the signal light is changed by the optical path changing unit 30A. Note that the remaining eight light emitting units 24 function for transmitting data signal light.

As a result, the optical path of at least a part of the signal light R is changed substantially parallel to the boundary surface L between the core layer 14 and the cladding layer 16, and the inside of the core layer 14 is directed toward the signal light emitting portion. To propagate. The signal light R always enters the light receiving surface of the light receiving element 36 of each sub-circuit board 34 at the same angle and is received by the light receiving element 36.

Thereafter, when the clock signal light R is received, the signal generated by the generation circuit 44 of the sub-circuit board 34 is transmitted to the control chip 40 via the first transmission line 38. At this time, while only the sub-circuit board 34 that has generated the signal in the generation circuit 44 transmits the signal, the other seven sub-circuit boards 34 are in the receiving state.

Next, when the signal light Q1 is emitted from the light emitting section 28B based on the signal, the signal light Q1 enters the inside of the optical data bus main body 12, and is diffused by the light diffusing section 28B. Then, the diffused signal light Q1 is supplied to the optical path changing unit 30B.
As a result, the optical path is made substantially parallel to the boundary surface L between the core layer 14 and the clad layer 16, and the clock signal R is transmitted in 8-bit parallel in the core layers 14 other than the core layer 14 to which the clock signal R has been transmitted.

The signal light Q1 passes through the signal light emitting portion of the optical data bus main body 14, and always enters the light receiving surface of the light receiving element 36 of each sub-circuit board 34 at the same angle. In the sub-circuit board 34 having the light receiving element 36 on which the signal light Q1 is incident, the processing circuit 46 performs signal processing based on the signal carried by the received signal light Q1.

Similarly, the signal light Q2 emitted from the light emitting section 24C is diffused by the light diffusing section 28C and then reflected by the optical path changing section 30C. Then, the signal light Q
The second optical path is substantially parallel to the boundary surface L between the core layer 14 and the cladding layer 16 and always enters the light receiving surface of the light receiving element 36 at the same angle.

As described above, according to the optical data bus used in the signal processing device 10 of the present embodiment, the signal light is transmitted to the light receiving surface of the light receiving element 36 disposed at the signal light emitting portion of the optical data bus main body 12. Are always incident at the same angle.
Further, even when a condensing lens (not shown) for condensing the signal light emitted from the signal light emitting portion to the light condensing element is used, the light-collecting efficiency depending on the incident angle is reduced. I will not do it.

Therefore, regardless of the connection position of the sub-circuit board 34 connected to the optical data bus, signal light having a uniform intensity can be transmitted efficiently.

Further, according to the signal processing device 10 using the optical data bus, it is possible to transmit and receive signal light having a small variation in signal strength between the plurality of sub-circuit boards 34. There is no need to adjust the signal level between the two. Further, the light emitting element 24 with a low light quantity can be used, and low power consumption can be realized.

Next, a signal processing device according to a second embodiment of the present invention will be described.

In the following description, the same components are denoted by the same reference numerals, and will not be described. FIG. 5 shows an optical data bus main body 54 used in the present embodiment.

Each light emitting section 2 of the laser diode array 22
4 and in different layers of the permeable medium 18,
A diffusion unit is provided.

This diffusion portion is a reflection type diffusion layer 50 in which silica-based white pigment is mixed into polyester, and an optical path changing portion formed at a position facing the diffusion layer 50 with the core layer 14 below in the stacking direction. 52.

The optical path changing portion 52 has a linear inclined surface T formed by projecting the cladding layer 16 inside the core layer 14.
The core of which is the core layer 14 and the cladding layer 16
Are formed in parallel to the boundary surface L. Assuming that the angle between the inclined surface T forming the optical path changing portion 52 and the boundary surface L between the core layer 14 and the cladding layer 16 is α, α is 2
It is formed in the range of 0 to 60 degrees.

Next, the operation of the present embodiment will be described.

When the clock signal light R is emitted from the light emitting section 24A, the signal light R enters the optical data bus main body 12, passes through the optical path changing section 52A as it is in the stacking direction, and passes through the light diffusing section 50A. Reflected and diffused.

The optical path of the signal light R is reflected by the inclined surface T of the optical path changing portion 52A, and the optical path of the signal light R is
Are substantially parallel to a boundary plane L between the two. Then, the signal light R is emitted from the signal light emitting portion and always enters the light receiving surface of the light receiving element 36 at the same angle.

The signal generated by the generation circuit 44 of the sub-circuit board 34 is transmitted through the transmission line 38, and the signal light Q1 is emitted from the predetermined light emitting section 24B via the control chip 40. Further, the signal light Q1 emitted from the light emitting unit 24B travels to the core layers 14 other than the lowermost core layer 14, and is reflected and diffused by the light diffusion unit 50B.
The core layer 14 is reflected by the inclined surface T of the optical path changing portion 52B.
The light is transmitted through the core layer 14 substantially parallel to the boundary surface L between the core layer 14 and the cladding layer 16. Then, the light receiving element 3 of the signal light emitting unit
6 is always incident on the light receiving surface at the same angle.

Similarly, the signal light Q2 emitted from the light emitting section 24C enters the optical data bus main body 12, and is reflected and diffused by the light diffusing section 50C. Then, the signal light Q2
Is changed substantially parallel to the boundary surface L by the light path changing path 52C. The light receiving element 3 of each sub-circuit board 34
6 are incident on the light receiving surface at the same angle.

In this embodiment, the same effects as in the first embodiment can be obtained.

[0064]

According to the optical data bus of the present invention, it is possible to reduce the variation in the transmission efficiency caused by the positional relationship between the light emitting unit and the light receiving unit. Further, signal light can be transmitted in all combinations regardless of the positional relationship between the light emitting unit and the light receiving unit.

Further, according to the signal processing device, it is possible to transmit and receive signal light with a small variation in signal strength between a plurality of sub-circuit boards, and therefore it is necessary to adjust the signal level between the respective sub-circuit boards. Disappears. Further, a light emitting element with a low light quantity can be used, and low power consumption can be realized.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a signal processing device according to a first embodiment of the present invention.

FIG. 2A is a plan view of an optical data bus used in a signal processing device, and FIG. 2B is a side view of the optical data bus.

FIG. 3 is a cross-sectional view of the optical data bus taken along the line AA ′ of FIG. 2;

FIG. 4 is a diagram illustrating an optical path of signal light transmitted through an optical data bus.

FIG. 5 is a diagram illustrating an optical path of signal light transmitted through an optical data bus used in a signal processing device according to a second embodiment of the present invention.

FIG. 6 is a plan view of a conventional optical data bus.

[Explanation of symbols]

 Reference Signs List 10 signal processing device 12 optical data bus main body (optical bus main body) 14 core layer 16 clad layer 24 light emitting section 28 light diffusing section 30 optical path changing section 34 sub-circuit board (circuit board) 36 light receiving element (light receiving section) 38 first Transmission line (transmission means) 40 Control chip (transmission means) 42 Second transmission means (transmission means) 44 Generation circuit 46 Processing circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nori Takanashi 430, Nakaicho, Ashigara-gun, Kanagawa Prefecture Green Tech Nakai Fuji Xerox Co., Ltd. F-term (reference) 2H047 KA02 KB08 LA00 MA07 QA05 TA00 5E338 AA00 BB75 CC01 CC10 5K002 BA02 BA07 DA10 FA01 GA07

Claims (2)

[Claims] 1. An optical bus main body for transmitting signal light in the core layer by alternately laminating a core layer and clad layers having a refractive index smaller than the refractive index of the core layer; A light diffusion portion for diffusing the signal light incident from the center of the bottom surface of the optical bus main body; and An optical path changing unit for transmitting the signal light into the core layer substantially in parallel with the optical data bus. 2. An optical bus body for alternately laminating a core layer and clad layers having a refractive index smaller than the refractive index of the core layer to transmit signal light in the core layer, and a bottom center of the optical bus body. A plurality of light emitting portions for injecting signal light into the optical bus; a light diffusing portion formed in the cladding layer and diffusing the signal light incident from the center of the bottom surface of the optical bus main body; and a boundary surface between the core layer and the cladding layer. An optical path changing unit that is formed and transmits the signal light into the core layer by making an optical path of the signal light diffused by the light diffusion unit substantially parallel to the boundary surface; and disposed at an outer edge of the core layer. A light receiving unit configured to receive the signal light whose optical path has been changed by the optical path changing unit; a generating circuit including the light receiving unit; and generating a signal to be carried by the signal light incident on the optical bus main body; and the optical bus main body Signal light emitted from the core layer A plurality of circuit boards on which at least one of a processing circuit that performs signal processing based on a signal is mounted; and a transmission unit that transmits a signal generated by the generation circuit or a signal processed by the processing circuit to the light emitting unit. And a signal processing device comprising: