JPH11202141A - Optical bus and signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress dispersion in the quantity of light made incident on the signal light incident terminal of a light receiving element or the like even when the relative position relation between the incident position and emission position of the signal light is changed by providing cylindrical lenses respectively having focus in a light diffusing body on the end face side of a light transmission layer. SOLUTION: Cylindrical lenses 12 and 13 are provided at positions adjacent to the end faces 11b and 11c of a light transmission layer 11. The cylindrical lenses 12 and 13 have focus in a light diffusing body 11a. Then, these lenses are used both for turning the incident signal light toward the light diffusing body 11a and collimating the signal light diffused by the light diffusing body 11a. Thus, the signal light which is diffused by the light diffusing body 11a and, emitted from the cylindrical lenses 12 and 13 advances from the front of condenser lenses 17 and 21 toward these condenser lenses 17 and 21. Therefore, the dispersion in the quantity of light to be received by respective light receiving elements 16 and 20 caused by the arranging positions of light emitting elements 15 and 19 and light receiving elements 16 and 20 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical bus for transmitting signal light and a signal processing device using the optical bus.

[0002]

2. Description of the Related Art With the 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, a data bus board (mother board) 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. Although the parallel bus has been improved by increasing the number of connection lines and miniaturization, the operation speed of the parallel bus has been improved.However, due to the signal delay caused by the capacitance between the connection lines and the resistance of the connection lines, the processing speed of the system becomes parallel. It may be limited by the operating speed of the bus. In addition, electromagnetic noise (E
MI: Electromagnetic Interf
issue) is also a significant 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. For an overview of optical interconnection technology, see "Tadaji Uchida, 9th Circuit Packaging Academic Conference, 15C01, p.
p. 201-202 "and" Hisami Tomimuro. , "Current State and Trend of Optical Interconnection Technology", IEEE Tokyo
o Section Denshi Tokyo N
o. 33 pp. 81-86, 1994], various modes are proposed depending on the configuration of the system.

[0004] Among various types of optical interconnection techniques 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. An example is disclosed in which light emitting / receiving devices are arranged on both front and back surfaces of each circuit board, and light emitting / receiving devices on adjacent circuit boards incorporated in the system frame are spatially optically coupled. A serial optical data bus for loop transmission between circuit boards has been proposed. In this method, signal light transmitted from one circuit board is transmitted to an adjacent circuit board by light / light.
Each of the circuit boards is sequentially arranged in series so that the electrical conversion is performed, the electrical / optical conversion is performed once again on the circuit board, and the signal light is transmitted to the next adjacent circuit board. Is transmitted between all circuit boards incorporated in the system frame while repeating electrical / optical conversion. For this reason, the signal transmission speed depends on the optical / electrical conversion speed and the electrical / optical conversion speed of the light receiving / light emitting device arranged on each circuit board, and at the same time is restricted. In addition, since data transmission between each circuit board is performed by optical coupling via a free space by a light receiving / light emitting device arranged on each circuit board, it is arranged on both front and back sides of an adjacent circuit board. Optical alignment of the light emitting / receiving device is required and all circuit boards need to be optically coupled. Furthermore, since the optical fibers are coupled via a free space, interference (crosstalk) between adjacent optical data transmission lines occurs, and poor data transmission is expected. In addition, it is expected that data transmission failure will occur due to scattering of signal light due to an environment in the system frame, for example, dust or the like. Further, 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 the fixed boards is fixed.

A technique for transmitting data between circuit boards using a two-dimensional array device is disclosed in Japanese Patent Application Laid-Open No. 61-196210.
No. 6,086,045. The technique disclosed herein comprises a plate facing a light source having two parallel surfaces,
This is a method in which circuit boards are optically coupled via an optical path constituted by a diffraction grating and a reflection element arranged on the plate surface. In this method, light emitted from one point can be connected only to a fixed point, and all circuit boards cannot be exhaustively connected like an electric bus. Also,
Since a complicated optical system is required and it is difficult to perform positioning, etc., interference (crosstalk) between adjacent optical data transmission paths occurs due to the displacement of the optical element, and poor data transmission is expected. Since connection information between circuit boards is determined by a diffraction grating and a reflective element arranged on the plate surface, there are various problems, such as the inability to freely insert and remove the circuit board and low expandability.

Another technique for transmitting data between circuit boards using a two-dimensional array device is disclosed in Japanese Patent Laid-Open No. 4-1344.
No. 15 discloses this. This publication discloses a lens array composed of a plurality of lenses having a negative curvature on a base made of a transparent substance having a higher refractive index than air, and a light source for emitting light emitted from a light source from a side surface of the lens array. A data transmission system provided with an optical system is disclosed. This publication also discloses a method of forming a region having a low refractive index or a hologram in the base, instead of a plurality of lenses having a negative curvature. In these systems, light incident from the side surface of the substrate is distributed to the upper surface of the substrate from a plurality of lenses having the above-described negative curvature, a region having a low refractive index instead of the lens, or a hologram, and emitted. It is configured to: Therefore, it is conceivable that the intensity of the emitted signal varies depending on the positional relationship between the incident position of the light and the plurality of lenses, the region having a low refractive index instead of the lens, and the emitting position on the substrate surface on which the hologram is formed. Also, it is considered that the ratio of light incident from the side surface of the base body to escape from the side surface opposite to the incident surface is high,
The efficiency of light used for signal propagation is low. Furthermore, since it is necessary to dispose a plurality of lenses having a negative curvature formed on the surface of the substrate and a region where the refractive index is low or an area where the hologram is used instead of the lens, the light input element of the circuit substrate is disposed. There are various problems that the degree of freedom is small and the expandability of the system is low.

[0007]

To solve these problems, it is conceivable to employ an optical bus that diffuses, propagates, and emits the incident signal light. However, if such an optical bus is simply manufactured, When signal light is incident from a certain incident position, the emission direction of the signal light emitted from the optical bus varies depending on the emission position of the signal light. In addition, when attention is paid to a certain emission position, the emission direction of the signal light emitted from the emission position varies depending on the incident position of the signal light. Therefore, if the light receiving element is arranged opposite to the emission position to receive the signal light emitted from the emission position, the relative position between the incident position of the signal light and the emission position of the signal light causes the light from the emission position. The amount of emitted signal light received by the light receiving element varies. For this reason,
When it is necessary to detect light with a wide dynamic range and a signal processing device is configured using such an optical bus, it is necessary to design a circuit that is suitable for the wide dynamic range. Design is difficult, and there is a problem that power consumption increases and costs increase.

In view of the above circumstances, the present invention reduces the variation in the amount of signal light incident on the signal light incident end of a light receiving element or the like even if the relative positional relationship between the incident position and the emission position of the signal light changes. It is an object of the present invention to provide an optical bus that can be suppressed and a signal processing device that achieves low power consumption and low cost.

[0009]

According to a first optical bus of the present invention for achieving the above object, (1) signal light enters from one end face, propagates inside, and emits the signal light from the other end face. An optical bus main body comprising a light diffusing means for diffusing a signal light to a predetermined point in the optical bus main body. An optical path changing means for directing the light to the light diffusing means disposed at a predetermined point; and (3) a collimating means provided on the other end face for collimating the signal light diffused by the light diffusing means and emitted from the other end face. It is characterized by having.

A second optical bus according to the present invention that achieves the above object is: (1) a core layer that receives signal light from one end face, propagates through the inside, and emits the signal light from the other end face; An optical bus main body in which a core layer having a light diffusing means for diffusing signal light at a predetermined point in the core layer and a clad layer having a refractive index lower than that of the core layer are alternately laminated. 2) an optical path converting means for directing the incident signal light to the light diffusing means arranged at the predetermined point for each of the plurality of core layers constituting the optical bus main body provided on the one end face side; For each of the plurality of core layers constituting the optical bus main body provided on the other end face side, there is provided a collimating means for collimating signal light diffused by the light diffusing means and emitted from the other end face. Features You.

A first signal processing apparatus according to the present invention, which achieves the above object, comprises: (1) a base (2) a signal light emitting end for emitting signal light and a signal light emitted from the signal light emitting end. At least one of a circuit for generating a signal to be carried and a circuit for performing signal processing based on a signal carried by the signal light incident from which the signal light is incident and a signal light incident from the signal light incident end are mounted. A plurality of circuit boards; (3) an optical bus main body that receives signal light from one end face, propagates through the inside, and emits the signal light from the other end face, and transmits the signal light to a predetermined point in the optical bus main body. An optical bus main body provided with a light diffusing means for diffusing light, an optical path converting means provided on the one end face, for directing the incident signal light to a light diffusing means arranged at the predetermined point, and the other end face The light diffusing hand provided on the side An optical bus having a collimating means for collimating the signal light diffused by the other end face and emitted from the other end face. (4) The circuit board is provided with a signal light emitting end or a signal light incident end mounted on the circuit board. A signal processing device comprising: a plurality of substrate fixing portions fixed on the base in a state of being optically coupled to a bus.

A second signal processing apparatus according to the present invention, which achieves the above object, comprises: (1) a base (2) a signal light emitting end for emitting signal light and a signal light emitted from the signal light emitting end. At least one of a circuit for generating a signal to be carried and a circuit for performing signal processing based on a signal carried by the signal light incident from which the signal light is incident and a signal light incident from the signal light incident end are mounted. A plurality of circuit boards; (3) a light diffusion layer for injecting signal light from one end face, propagating through the inside and emitting signal light from the other end face, and diffusing the signal light to a predetermined point in the core layer; An optical bus body in which a core layer having means and a clad layer having a refractive index lower than the refractive index of the core layer are alternately stacked, and the optical bus body provided on the one end surface side, Each of the multiple core layers The optical path conversion means for directing the incident signal light to the light diffusion means arranged at the predetermined point, and the plurality of core layers constituting the optical bus main body provided on the other end face side, An optical bus having collimating means for collimating the signal light diffused by the light diffusing means and emitted from the other end face. (4) The circuit board is connected to a signal light emitting end or a signal light incident end mounted on the circuit board. Are provided with a plurality of substrate fixing portions that are fixed on the base in a state of being optically coupled to the optical bus.

[0013]

Embodiments of the present invention will be described below. FIG. 1 shows an optical bus according to a first embodiment of the present invention;
FIG. 3 is a diagram showing a circuit board arranged around the optical bus. The optical bus 10 includes a flat optical transmission layer 11 for transmitting signal light. This optical transmission layer 11 is an optical bus 10
Of the main body. One end face 11b and the other end face 11c of the light transmission layer 11 are signal light input / output end faces that both serve to input signal light and output signal light. The optical transmission layer 11 converts the signal light incident from the end faces 11b, 11c into opposite end faces 11c, 11b, respectively.
A light diffuser 11a for diffusing signal light is provided at the center of the light transmission layer 11.

The optical bus 10 has a cylindrical lens 12 having a cylindrical lens surface at a position adjacent to the end faces 11b and 11c of the optical transmission layer 11, respectively.
13 are provided. This cylindrical lens 1
Reference numerals 2 and 13 have the same focal length.
Each of the cylindrical lenses 12 and 13 has a focus on the light diffuser 11a. Cylindrical lens 12, 1
3 has both functions of an optical path changing means for directing the incident signal light to the light diffuser 11a and a collimating means for collimating the signal light diffused by the light diffuser 11a; Each cylindrical lens 12,
The operation of 13 will be described later.

On the optical bus 10 shown in FIG. 1, four circuit boards 14 are arranged facing the cylindrical lens 12, and four circuit boards 18 are arranged facing the cylindrical lens 13. . These circuit boards 14 and 1
Numeral 8 is arranged so as to extend perpendicularly to the paper surface of FIG. On each of the circuit boards 14 and 18, light emitting elements 15 and 19 for emitting signal light, light receiving elements 16 and 20 for receiving signal light, and the cylindrical lens 1 are provided.
A condenser lens 17 for converging the signal light collimated by each of the light receiving elements 2 and 13 toward each of the light receiving elements 16 and 20;
21 are provided.

As a material of the light transmission layer 11 and the cylindrical lenses 12 and 13, for example, polymethyl methacrylate (PMMA) can be used. In order to manufacture the optical transmission layer 11 and the cylindrical lenses 12 and 13 using this PMMA, for example, a mold for each of the optical transmission layer and the cylindrical lens into which the PMMA is poured is prepared, and the mold is heated to a temperature at which the PMMA is sufficiently melted. , And P is sufficiently heated and in a molten state
The MMA may be poured into the mold, cooled slowly over time, and then removed from the mold. Optical axis Hereinafter, how the light emitting element emits signal light and the signal light enters the light receiving element will be described.

FIG. 2 and FIG. 3 are explanatory diagrams thereof.
1 shows the left half (on the side of the cylindrical lens 12) of the optical bus 10 shown in FIG. 1 and a circuit board 14 arranged opposite to the cylindrical lens 12, and FIG.
The right half of the optical bus 10 shown in FIG.
2) and a circuit board 18 arranged to face the cylindrical lens 13. Here, a case where signal light is incident from the cylindrical lens 12 will be described.

As shown in FIG. 2, the signal light 31 (here, the signal light emitted from the light emitting element 15 is a signal light traveling parallel to the optical axis 35) is emitted from the light emitting element 15. Then, the signal light 31 enters the cylindrical lens 12. Here, since the cylindrical lens is used, the optical path of the signal light 31 is not converted in the thickness direction of the optical transmission layer 11, but since the cylindrical lens 12 has a focus on the light diffuser 11a, the signal light 31 The light 31 travels in the width direction of the optical transmission layer 11 (the end face 11 b
(Longitudinal direction) becomes the signal light 32 whose optical path has been converted so as to be directed to the light diffuser 11a.

As described above, the cylindrical lens 12
Since the optical path is not changed in the thickness direction of the light transmission layer 11, high precision is required for optical alignment between the cylindrical lens 12 and the end face 11 b of the light transmission layer 11 in the thickness direction of the light transmission layer 11. In addition, alignment of the cylindrical lens 12 can be easily performed. For the same reason, the positioning can also be easily performed on the cylindrical lens 13 disposed on the end face 11c side of the optical transmission layer 11 of the optical bus 10.

The light diffuser 1 included in the light transmission layer 11
1a is a signal light that has entered the end face 11b of the optical transmission layer 11 and has reached the light diffuser 11a.
1c (see FIG. 1) and diffuses over the entire length of the end face 11c, while the light diffuser 1 is incident from the end face 11c.
1a is a light-transmissive light diffuser that diffuses the signal light toward the end face 11b of the optical transmission layer 11 over the entire length of the end face 11b.
, The signal light 32 propagating toward the light diffuser 11a, as shown in FIG.
The spread signal light 33 spreads toward 1c (here, the spread signal light 33 spread by the light diffuser 11a is indicated by four arrows). The diffused signal light 33 propagates while spreading in the width direction of the optical transmission layer 11 (longitudinal direction of the end face 11 c), and enters the cylindrical lens 13. here,
Since the cylindrical lens is used, the diffusion signal light 33 incident on the cylindrical lens 13 is collimated only in the width direction of the light transmission layer 11 in the width direction and the thickness direction (that is, in the width direction). Only the signal light 34 that travels in parallel with the optical axis 36 becomes the signal light 34 (here, the collimated signal light 34 is indicated by four arrows). The signal light 34 propagates from the front of the condenser lens 21 of each circuit board 18 toward the condenser lens 21 and is condensed by the condenser lens 21. Is received at.

As described above, the cylindrical lens 13
Since the thickness direction of the optical transmission layer 11 is not collimated, high precision is not required for optical alignment between the cylindrical lens 13 and the light receiving element 20 in the thickness direction of the optical bus 10, and the position of the light receiving element 20 is not required. The alignment can be easily performed. For the same reason, the positioning of the light receiving element 16 disposed on the cylindrical lens 12 side can be easily performed.

In this case, one of the four circuit boards 14 shown in FIG.
In the case where the signal light 31 is emitted from the circuit board 14 other than the circuit board 14, the signal light is also transmitted to the light diffuser 11 a by the cylindrical lens 12 through the cylindrical lens 12. Is converted and diffused by the light diffuser 11a toward the end face 11c, and the diffused signal light is collimated by the cylindrical lens 13 only in the width direction of the light transmission layer 11,
The light is received by each light receiving element 20. In the above description, the case where the signal light is emitted from the circuit board 14 arranged on the left side of FIG. 1 and the signal light is received by the circuit board 18 arranged on the right side has been described. When the signal light is emitted from the circuit board 18 disposed on the right side of the light diffuser 11, the signal light is transmitted to the light diffuser 11 a by the cylindrical lens 13.
The optical path is changed so as to go to. The signal light whose optical path has been converted is diffused toward the end face 11b by the light diffuser 11a, and the diffused signal light is
Is collimated only in the width direction of the light transmission layer 11. The collimated signal light is applied to each circuit board 14
The light propagates from the front of the condenser lens 17 toward the condenser lens 17, is condensed by the condenser lens 17, and the collected signal light is received by the light receiving element 16.

That is, no matter which light emitting element emits the signal light, the signal light diffused by the light diffuser 11a and emitted from the cylindrical lenses 12, 13 is collected from the front of the condenser lenses 17, 21 respectively. It proceeds toward the lenses 17 and 21. Therefore, the variation in the light quantity of the signal light received by each light receiving element due to the arrangement position of the light emitting element and the light receiving element is suppressed.

The operation of the optical bus 10 shown in FIG.
The operation will be described in comparison with the operation of an optical bus (comparative example) not provided with a collimating means for collimating and emitting signal light. FIG. 4 is a plan view showing an optical bus having no collimating means. The optical bus 40 includes an optical transmission layer 41 for transmitting the signal light and a light diffusion layer 42 for diffusing the signal light toward the inside of the optical transmission layer 41. It is adhered to the end face of the layer 41. The optical bus 40 receives signal light from an end face 43 on the light diffusion layer 42 side and emits the signal light from an end face 44 opposite to the end face 43. Further, the end face 43 of this optical bus 40
Are arranged along the three light emitting elements 45, 46, 47,
Along the end face 44 of the optical bus 40, four light receiving elements 48, 4
9, 50 and 51 are arranged. In addition, this end face 44
Between the light receiving elements 48, 49, 50, and 51, a condenser lens 52, which condenses the signal light emitted from the end face 44.
53, 54 and 55 are provided.

Here, the three light emitting elements 45, 46, 47
When the signal light is emitted from one of the light emitting elements (here, the light emitting element 45), of the signal light diffused by the light diffusion layer 42, the signal light 56 propagating toward the condenser lens 52 is Since the light enters the condenser lens 52 from the front with respect to the condenser lens 52, the signal light 56 condensed by the condenser lens 52 efficiently enters the light receiving element 48,
The signal light 57 propagating toward the condenser lens 53 enters the condenser lens 53 obliquely with respect to the condenser lens 53. Therefore, compared to the amount of light incident on the light receiving element 48,
The amount of light incident on the light receiving element 49 decreases. Light receiving element 5
For each of 0 and 51, although the signal lights 58 and 59 propagate toward the condenser lenses 54 and 55, respectively.
The amount of light incident on each of the light receiving elements 50 and 51 further decreases. Also, the four condenser lenses 52, 53, 54, 5
5, focusing on one certain condensing lens, depending on which of the three light emitting elements 45, 46, and 47 emits the signal light, the incident direction of the signal light incident on the condensing lens is determined. Variation, and as a result, the amount of incident light varies.

That is, the amount of light incident on the light receiving element varies depending on the relative positional relationship between the position of the light emitting element that emits the signal light and the position of the light receiving element that receives the signal light. On the other hand, since the optical bus 10 shown in FIG. 1 includes the cylindrical lenses 12 and 13 for collimating and emitting the signal light, the signal emitted from each of the cylindrical lenses 12 and 13 is independent of the position of the light emitting element. Light is collected from the front of the condenser lenses 17 and 21 respectively.
Incident on. For this reason, as compared with the optical bus 40 shown in FIG. 4, variation in the amount of signal light incident on the light receiving element is suppressed.

Note that the cylindrical lenses 12 and 13 constituting the optical bus 10 have cylindrical lens surfaces, and thus have a cylindrical lens function. For example, instead of the cylindrical lenses 12 and 13, for example, A lens having a Fresnel lens surface acting as a cylindrical lens may be provided. Since the lens has a Fresnel lens surface, the thickness of the lens can be reduced.

The optical bus 10 includes a light transmission layer 11 and a cylindrical lens 12, which are separate members.
Although the optical bus 13 is used, the optical bus may be formed by integrally forming the optical transmission layer and the cylindrical lens by processing the end face of the optical transmission layer 11 into the shape of a lens surface that functions as a lens. The optical bus 10 includes a light transmitting type light diffuser 11a, and the light diffuser 11a
Although the signal light incident from the end faces 11b and 11c of the light transmission layer 11 is diffused toward the opposite end faces 11c and 11b, the signal light is transmitted in all directions instead of the transmissive light diffuser 11a. A light diffuser for diffusing light may be provided. When a light diffuser that diffuses signal light in all directions is provided, the signal light incident on the optical bus is converted into cylindrical lenses 12 and 13.
The light can be emitted from both at the same time, and the signal light emitted from the light emitting element mounted on a certain circuit board can be transmitted to all the light receiving elements mounted on all other circuit boards.

The optical bus 10 is provided with cylindrical lenses 12 and 13 so that the optical bus 10
The optical path is converted so that the signal light is directed toward the light diffuser 11a only in the width direction among the thickness direction and the width direction of
Although the collimator is collimated only in the width direction out of the thickness direction and the width direction of the optical bus 10, the signal light incident on the optical bus 10 propagates toward the light diffuser 11a, or the optical bus 10 and the light receiving element Is adjusted so that the signal light emitted from the optical bus 10 propagates toward the light receiving element, the signal is transmitted in both the thickness direction and the width direction of the optical bus 10. Light is light diffuser 1
The optical path may be changed so as to propagate toward 1a, or the signal light may be collimated in both the thickness direction and the width direction of the optical bus 10.

FIG. 5 is a diagram showing an optical bus according to a second embodiment of the present invention and a circuit board disposed around the optical bus. The light transmission layer 11 shown in FIG.
However, the light transmission layer 61 shown in FIG. 6 includes a light diffuser 61a near one end face 61b. The optical bus 60 shown in FIG.
b, 61c each side cylindrical lens 6
2 and 63 are provided. The cylindrical lens 62
The length of the light transmission layer 61 in the width direction is shorter than that of the cylindrical lens 63. The focal lengths f _a and f _b of these cylindrical lenses 62 and 63 are different from each other, and f _a <f _b . Each of the cylindrical lenses 62 and 63 has a focus on the light diffuser 61a.

In the optical bus 60 shown in FIG. 5, three circuit boards 64 are arranged to face the cylindrical lens 62, and four circuit boards 65 are arranged to face the cylindrical lens 63. . The circuit boards 64 and 65
Like the circuit boards 14 and 18 shown in FIG. 1, a light emitting element, a light receiving element, and a condenser lens are mounted (the light emitting element, the light receiving element, and the condenser lens are not shown).

Even if the focal lengths of the cylindrical lenses 62 and 63 of the optical bus 60 are different from each other, the optical path of the signal light can be adjusted by adjusting the position of the light diffuser 61a provided in the optical transmission layer 61. The signal light can be directed toward the light diffuser 61a and collimated and emitted from the signal light diffused by the light diffuser 61a. Thus, as long as the focal points of both the two cylindrical lenses are located at the light diffuser, the light diffuser may be located at any position in the light transmission layer.

FIG. 6 is a perspective view showing an optical bus according to the third embodiment of the present invention. The optical bus 70 includes a core layer 71,
Laminate 7 composed of clad layer 72 and light absorbing layer 73
4 is provided. The core layer 71 corresponds to the optical bus 10 shown in FIG.
The optical transmission layer 11 has the same structure as that of the optical transmission layer 11, and a light diffuser (not shown) for diffusing signal light is provided at a predetermined point in the core layer 71. The cladding layer 72
Has a refractive index lower than that of the core layer 71, and the cladding layer 72 is formed on the front and back surfaces of the core layer 71. The light absorbing layer 73 prevents light transmitted through the core layer 71 from leaking from the cladding layer 72 and entering another core layer 71.
The cladding layers 72 on which the core layers 71 are formed are alternately stacked.

A cylindrical lens 75 is provided on one end face of the laminated body 74, and a cylindrical lens 76 is provided on the opposite end face. Each of the cylindrical lenses 75 and 76 has, for each of the core layers 71, an optical path conversion unit for directing the incident signal light to the light diffuser included in the core layer 71, and collimates the signal light diffused by the light diffuser. It has both functions of the collimating means. Each cylindrical lens 7
Each of the lenses 5 and 76 has a focal point for all the light diffusers included in each core layer 71, and the focal lengths thereof are all equal.

In the optical bus 70 thus configured, when signal light enters the cylindrical lenses 75 and 76, the optical path is converted so that the signal light travels toward the light diffuser only in the width direction of each core layer 71. You. Therefore, as described with reference to FIG. 2, the positioning of the cylindrical lens can be easily performed. The signal light diffused by the light diffuser by the cylindrical lenses 75 and 76 is collimated only in the width direction of the light transmission layer 71. Therefore, as described with reference to FIG. 3, it is possible to easily perform the alignment of the light receiving element that receives the signal light emitted from the cylindrical lenses 75 and 76.

Further, since the optical bus 70 includes the plurality of optical transmission layers 71, signal light composed of bits corresponding to the respective optical transmission layers 71 can be transmitted and received as parallel signals. Further, since the optical bus 70 has the clad layer 72 laminated between the optical transmission layers 71, crosstalk of signal light between the adjacent optical transmission layers 71 is suppressed.
Since the light absorption layer 73 is provided in addition to the light absorption layer 2, the crosstalk of the signal light is more efficiently suppressed.

FIG. 7 is a perspective view showing an optical bus according to a fourth embodiment of the present invention. In describing the optical bus shown in FIG. 7, the same components as those of the optical bus 70 shown in FIG. 6 are denoted by the same reference numerals, and the optical bus 70 shown in FIG.
Only the differences from the above will be described. The optical bus 80 includes a stacked body 82, and the light absorbing layer 81 included in the stacked body 82 has an edge projecting beyond the core layer 71 and the clad layer 72. The optical bus 80 includes cylindrical lenses 83 and 8 having the same structure as the cylindrical lenses 12 and 13 included in the optical bus 10 shown in FIG.
4 is provided. These cylindrical lenses 83 and 84
Are arranged alternately with the protruding portions of the light absorbing layer 81 for each of the core layers.

As described above, the cylindrical lens 83,
By arranging 84 at the protruding portion of the light absorbing layer 81, it is possible to prevent the light that has entered the cylindrical lenses 83, 84 from leaking from the cylindrical lenses 83, 84 and entering the adjacent cylindrical lenses 83, 84.
FIG. 8 is a perspective view illustrating a signal processing device according to an embodiment of the present invention.

This signal processing device 90 has an optical bus 70 shown in FIG.
1 (an example of the substrate according to the present invention). Further, the signal processing device 90 includes a plurality of circuit boards 96. On each circuit board 96, a light receiving / emitting element 94 composed of a pair of a light emitting element and a light receiving element, and an electronic circuit 95 are mounted. The light emitting / receiving element 94 emits signal light,
The electronic circuit 95 is an element for receiving signal light,
The circuit includes both a circuit for generating a signal to be carried by the signal light emitted from the light receiving / emitting element 94 and a circuit for performing signal processing based on the signal carried by the signal light received by the light receiving / emitting element 94. . The circuit board 96 is in a state where the light receiving / emitting element 94 mounted on the circuit board 96 is optically coupled to the cylindrical lenses 75 and 76 of the optical bus 70 by the board fixing portion 93 provided on the motherboard 91. Is fixed on the motherboard 91. Further, on the motherboard 91, a control circuit 92 for controlling the operation of the electronic circuit 95 mounted on each circuit board 96 is mounted.

The signal processing device 90 thus configured
When the electronic circuit 95 generates an electric signal to be carried by the signal light emitted from the light receiving / emitting element 94 according to a command from the control circuit 92 mounted on the motherboard 91, the electric signal is converted into a signal light by the light receiving / emitting element 94 Is converted. The signal light enters the cylindrical lens 75 (or the cylindrical lens 76) of the optical bus 70, and its optical path is converted toward a light diffuser (not shown) provided in each optical transmission layer 71 of the optical bus 70. You. The signal light whose optical path is converted is diffused by the light diffuser and collimated by the cylindrical lens 76 (or the cylindrical lens 75) only in the width direction of the light transmission layer 71. The collimated signal light is received by the light receiving / emitting element 94, converted into an electric signal, and subjected to signal processing.

Since the signal processing device 90 includes the optical bus 70 having the above-described configuration, the relative position of the cylindrical lenses 75 and 76 between the position where the signal light is incident and the position where the signal light is emitted. Even if the positional relationship changes, variation in the amount of signal light incident on the light receiving / emitting element 94 is suppressed. Therefore, there is no need to detect light having a wide dynamic range, and the circuit design of the electronic circuit 95 is facilitated. Therefore, the processing speed of the signal processing device can be increased and the power consumption can be reduced.

Further, in the signal processing device 90, each of the circuit boards 96 is fixed to the board fixing portion 93, and at the same time, the light receiving / emitting elements 94 mounted on the circuit board 96 are optically coupled to the optical bus 70. It does not require delicate alignment. The signal processing device 90 includes an optical bus 70 having a laminated structure. Instead of the optical bus composite 70, a single-layer optical bus 10 as shown in FIG. You may comprise.

In this signal processing device 90, a light receiving / emitting element 94 composed of a pair of a light emitting element and a light receiving element is mounted on each circuit board 96, and the light emitting element and the light receiving element are respectively mounted on different circuit boards. The signal processing device may be configured to be mounted.

[0044]

Embodiments of the present invention will be described below. The optical bus 10 having the configuration shown in FIG. 1 was used as an example of the optical bus, and the optical bus 40 having the configuration shown in FIG. 4 was used as a comparative example of the optical bus. Optical bus 1 of this embodiment and comparative example
For the 0,40 light transmission layers, polymethyl methacrylate (PMMA) molded to a thickness of 0.5 mm was used. Further, as the cylindrical lenses 12 and 13 included in the optical bus 10 of the embodiment, those manufactured using PMMA which is the same material as the material of the light transmission layer 11 were used. less than,
An experimental method performed using each of the optical buses of the example and the comparative example will be described, and then the experimental results will be described.

FIGS. 9 and 10 are explanatory diagrams of the experimental method. As shown in FIG. 9, the optical bus 10 of the embodiment receives the signal light 100 from a position A near the side surface of the optical transmission layer 11 of the cylindrical lens 12 and receives the signal light 1.
00 was diffused by the light diffuser 11a, and the intensity of the signal light emitted from the cylindrical lens 13 was measured.

As shown in FIG. 10, the optical bus 40 of the comparative example receives the signal light 200 from the position X near the side surface 41a of the light transmission layer 41 of the light diffusion layer 42, and And the intensity of the signal light emitted from the end face 44 of the optical transmission layer 41 was measured. FIG. 11 is a graph showing the result. The horizontal axis of this graph is the emission angle θ. In the optical bus 10 of the embodiment, the signal light propagates in the direction of the optical axis 13a of the cylindrical lens 13 in the optical bus 10 according to the embodiment. 9 with respect to the angle .theta.
In the optical bus 40 of the comparative example, the light diffusion layer 42
Is an angle θ (see FIG. 10) between each signal light that is diffused and propagates toward the end face 44 of the optical transmission layer 41 and the signal light 201 that travels in parallel with the side surface 41a of the optical transmission layer 41. The vertical axis of the graph indicates the intensity of the signal light. In the optical bus 10 of the embodiment, the intensity of the signal light having an angle θ with the signal light 101 (see FIG. 9) is represented by the signal light 101. Of the optical bus 4 of the comparative example.
At 0, the intensity of the signal light having an angle θ with the signal light 201 (see FIG. 10) is indicated by a relative value with the intensity of the signal light 201 being 100.

As can be seen from the graph of FIG. 11, the variation of the intensity of the signal light due to the emission angle is smaller in the optical bus 10 of the embodiment than in the optical bus 40 of the comparative example. For this reason, it is not necessary to detect signal light having a wide dynamic range, and it is understood that the use of the optical bus of the present invention can provide a signal processing device with low power consumption and low cost.

[0048]

As described above, according to the optical bus of the present invention, even if the relative positional relationship between the incident position and the outgoing position of the signal light changes, the signal light enters the signal light incident end of the light receiving element or the like. Variations in the amount of incident signal light can be suppressed. Further, according to the signal processing device of the present invention, low power consumption and cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an optical bus according to a first embodiment of the present invention and a circuit board disposed around the optical bus.

FIG. 2 is a diagram showing a left half of the optical bus shown in FIG. 1 (on the side of the cylindrical lens 12) and a circuit board disposed so as to face the cylindrical lens 12.

FIG. 3 is a diagram showing a right half of the optical bus shown in FIG. 1 (on the side of the cylindrical lens 13) and a circuit board arranged so as to face the cylindrical lens 13.

FIG. 4 is a top view showing an example of an optical bus without a collimator.

FIG. 5 is a diagram illustrating an optical bus according to a second embodiment of the present invention and a circuit board disposed around the optical bus.

FIG. 6 is a perspective view showing an optical bus according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing an optical bus according to a fourth embodiment of the present invention.

FIG. 8 is a perspective view illustrating a signal processing device according to an embodiment of the present invention.

FIG. 9 is an explanatory diagram of an experimental method performed using the optical bus of the example.

FIG. 10 is an explanatory diagram of an experimental method performed using an optical bus of a comparative example.

FIG. 11 is a graph showing a change in intensity of signal light with respect to an emission angle.

[Explanation of symbols]

10, 40, 60, 70, 80 Optical bus 11, 41, 61 Optical transmission layer 11a, 61a Optical diffuser 11b, 11c, 43, 44, end face 12, 13, 62, 63, 75, 76, 83, 84 cylindrical Lens 14, 18, 64, 65, 96 Circuit board 15, 19, 45, 46, 47 Light emitting element 16, 20, 48, 49, 50, 51 Light receiving element 17, 21, 52, 53, 54, 55 Condensing lens 31, 32, 33, 34, 56, 57, 58, 59, 1
00, 101, 200, 201 signal light 35, 36 optical axis 42 light diffusion layer 71 core layer 72 clad layer 73, 81 light absorption layer 74, 82 laminate 90 signal processing device 91 motherboard 92 control circuit 93 substrate fixing portion 94 Light emitting device 95 Electronic circuit

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H04B 10/26 10/14 10/04 10/06 (72) Inventor Kenichi Kobayashi 430 Nakai-cho Sakai-gun, Kanagawa Prefecture Green Tech Nakai Fuji Xerox Co., Ltd. (72) Inventor Masanori Hirota 430 Nakaicho, Nakai-cho, Ashigara-gun, Kanagawa Prefecture Inside Fuji Xerox Fuji Xerox Co., Ltd. Shinobu Koseki 430 Nakai-cho, Nakai-machi, Ashigara-gun, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd.

Claims (8)

[Claims] 1. An optical bus body for receiving signal light from one end face, propagating through the inside and emitting the signal light from the other end face, and diffusing the signal light to a predetermined point in the optical bus body. An optical bus main body provided with light diffusing means, provided on the one end face side, an optical path conversion means for directing incident signal light to a light diffusing means arranged at the predetermined point, and on the other end face side An optical bus, comprising: a collimating means provided for collimating the signal light diffused by the light diffusing means and emitted from the other end face. 2. A light diffusion means for injecting signal light from one end face, propagating through the inside and emitting the signal light from the other end face, and diffusing the signal light to a predetermined point in the core layer. An optical bus main body comprising a core layer having: and a cladding layer having a refractive index lower than the refractive index of the core layer, the optical bus main body being provided on the one end surface side, the optical bus main body comprising: For each of the plurality of core layers, the optical path converting means for directing the incident signal light to the light diffusing means disposed at the predetermined point, and the plurality of optical layers provided on the other end face side, constituting the optical bus main body. An optical bus, comprising: a collimator for each of the core layers, for collimating signal light diffused by the light diffuser and emitted from the other end face. 3. The light according to claim 1, wherein the optical path conversion means performs an optical path conversion function only in the width direction of the optical bus in the width direction and the thickness direction. bus. 4. An optical bus according to claim 1, wherein said optical path changing means has a Fresnel lens surface. 5. The optical bus according to claim 1, wherein the collimating means performs a collimating action only in the width direction of the optical bus in the width direction and the thickness direction. 6. The apparatus according to claim 1, wherein said collimating means has a Fresnel lens surface.
The mentioned optical bus. 7. A base, a signal light emitting end for emitting signal light, a circuit for generating a signal to be carried by the signal light emitted from the signal light emitting end, a signal light incident end for receiving the signal light, and the signal A plurality of circuit boards on which at least one of a circuit for performing signal processing based on a signal carried by the signal light incident from the light incident end is mounted; An optical bus main body that emits the signal light from an end face, the optical bus main body including light diffusion means for diffusing the signal light to a predetermined point in the optical bus main body, and the optical bus main body is provided on the one end face side; An optical path changing means for directing the incident signal light to a light diffusing means disposed at the predetermined point, and a signal light provided on the other end face side and diffused by the light diffusing means and emitted from the other end face. Collimating means for collimating An optical bus provided, and a plurality of substrate fixing means for fixing the circuit board on the base such that a signal light emitting end or a signal light incident end mounted on the circuit board is optically coupled to the optical bus. And a signal processing device. 8. A base, a signal light emitting end for emitting signal light, a circuit for generating a signal to be carried by the signal light emitted from the signal light emitting end, a signal light incident end for receiving signal light, and the signal A plurality of circuit boards on which at least one of a circuit for performing signal processing based on a signal carried by the signal light incident from the light incident end is mounted; A core layer that emits signal light from an end face, the core layer including light diffusion means for diffusing signal light to a predetermined point in the core layer, and a cladding layer having a refractive index lower than the refractive index of the core layer; Are alternately stacked, and for each of a plurality of core layers constituting the optical bus main body provided on the one end surface side, light diffusion is performed in which the incident signal light is disposed at the predetermined point. Light path changing hand to means And a collimating means provided on the other end face side, for each of a plurality of core layers constituting the optical bus main body, for collimating signal light diffused by the light diffusing means and emitted from the other end face. A plurality of substrate fixing portions for fixing the optical bus and the circuit board on the base in a state where a signal light emitting end or a signal light incident end mounted on the circuit board is optically coupled to the optical bus. A signal processing device comprising: