JP2001051141A - Optical bus and signal processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a high-speed signal transmission between circuit boards and to obtain a signal light having a uniform luminous intensity in each circuit board. SOLUTION: A translucent medium 2 comprises a diffraction element 11 and a light lead-through element 12 provided in positions opposite to a light emitting element 6 and a light receiving element 8 on each circuit board 4. The diffraction element 11 separates a signal light 5 incident from the light emitting element 6 into two signal lights 5a and 5b, bends the signal light 5a toward the left end 2a of the translucent medium 2 and the signal light 5b toward the right end 2b of the translucent medium 2 at an angle α in the lateral direction of the translucent medium 2, and advances them within the translucent medium 2 while totally reflecting them by the reverse side and surface side thereof. The signal light 5a and signal light 5a form beam spots near the respective light lead-through bodies 12 of adjacent optical branching means on the right and left, respectively. The overlapping part with the lead-through body 12 of each beam sport is led out of the translucent medium 2 and received by the light receiving element 8, and the non-overlapping part with the lead-through body 12 is further advanced in the translucent medium 2 while being totally reflected to further form a beam spot near the light lead-through body 12 of the adjacent optical branching means on the left or the right.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical bus (optical data bus) for branching and transmitting an optical signal, and a signal processing device for performing signal processing including optical transmission by the optical bus.

[0002]

2. Description of the Related Art With the development of VLSI (Very Large Scale Integrated Circuit), the circuit functions of circuit boards (daughter boards) used in data processing systems have been greatly increased. Since the number of signal connections increases, a data bus board (motherboard) for connecting each circuit board with a bus structure employs a parallel architecture that requires a large number of connection connectors and connection lines.

In the parallel architecture, 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. However, signal delay caused by the capacitance between connection lines and the resistance of connection lines has been attempted. Therefore, the processing speed of the data processing system may be limited by the operation speed of the parallel bus. In addition, electromagnetic noise (EMI: Electromagnng) caused by increasing the density of connection wirings of the parallel bus.
Also, the problem of the occurrence of technic interference (E.E.I.E.I.E.I.E.I.E.I.E.I.E.I.E.I.E.I.C.

In order to solve such a problem and improve the operation speed of the parallel bus, an optical connection technique in a system called optical interconnection has been considered. As for the optical interconnection, see “Tadaji Uchida, 9th Circuit Packaging Academic Conference, 15C01, pp. 201-20
2 ”and“ H. Tomimiuro, et al. , “Pa
caging Technology for Op
physical Interconnects ", IEEE
Tokyo, No. 33 pp. 81-86,199
4], various forms have been proposed depending on the configuration of the system.

As one of the optical interconnections,
(1) JP-A-2-41042 discloses that a light emitting element and a light receiving element are arranged on both front and back surfaces of each circuit board incorporated in a system frame, and a space between the light emitting element and the light receiving element on an adjacent circuit board is spatially provided. An optically coupled optical bus for loop transmission between circuit boards is shown. In this method, the signal light transmitted from a certain circuit board is subjected to optical / electrical conversion on an adjacent circuit board, and further subjected to electrical / optical conversion on that circuit board, so that the signal light is transmitted to the next adjacent circuit board. Each circuit board is sequentially optically connected in series so that signal light is transmitted to all circuit boards incorporated in the system frame while repeating optical / electrical conversion and electrical / optical conversion on each circuit board. Transmitted.

Also, (2) Japanese Patent Application Laid-Open No. 61-196210 discloses a method of optically connecting circuit boards by an optical path constituted by a diffraction grating and a reflection element arranged on a plate. .

Further, as a method of transmitting data between circuit boards by an optical connection device having an optical branching means,
(3) JP-A-58-42333 discloses that data transmission between circuit boards is performed by arranging a plurality of circuit boards perpendicularly to an optical transmission path on which a half mirror is arranged. 4) Japanese Patent Application Laid-Open No. 4-134415 discloses that signal light is made incident from a side surface of a lens array in which a plurality of lenses are arranged two-dimensionally, and signal light is emitted from each lens. In Japanese Patent Application Laid-Open No. 63-1223, a plurality of optical couplers having different branching ratios are arranged in series in an optical fiber line so that the branching ratio increases in order from the starting end of the line, and the incident light is converted into light having substantially uniform intensity. It is shown that the signal is branched and output.

(5) As an optical coupler that can be used in the method of JP-A-63-1223, (6) IEEE
E Photonics Technology Le
ters, vol. 8, No. 12, Decembe
r (1996) "shows an optical fiber in which a V-groove is formed.

[0009]

However, (1)
In the method of Japanese Patent Application Laid-Open No. 2-41042, the signal transmission speed is
There is a problem that the speed depends on the light-to-electric conversion and the electric-to-light conversion of the light receiving element and the light emitting element on each circuit board. In addition, since light coupling between a light receiving element and a light emitting element on each circuit board via a free space is used for data transmission between adjacent circuit boards, interference (crosstalk) between adjacent optical transmission paths occurs. This may cause a data transmission failure. Further, it is conceivable that signal light is scattered by, for example, dust or the like due to the environment in the system frame, thereby causing data transmission failure.

[0010] (2) In the method disclosed in Japanese Patent Application Laid-Open No. 61-196210, light emitted from one point can be connected only to a fixed point, so that all circuit boards are comprehensively connected like an electric bus. There is a problem that cannot be connected.

(3) In the method disclosed in Japanese Patent Application Laid-Open No. 58-42333, since a plurality of half mirrors are used, the size of the apparatus is increased, and the optical alignment of the light emitting element and the light receiving element is performed for each half mirror. Is necessary. Moreover, the signal light that has passed through the half mirror has almost half the light intensity of the signal light before passing through. Therefore, by repeating light branching a plurality of times, the light intensity becomes weak, and the light receiving element However, there is also a problem that a sufficient light intensity cannot be obtained, and in some cases, signal transmission becomes impossible.

(4) In the method disclosed in Japanese Patent Application Laid-Open No. 4-134415, the closer the lens is to the light incident position, the larger the amount of emitted light becomes. Therefore, the intensity of the output signal light depends on the positional relationship between the incident position and the output position. There is a problem that variation occurs. In addition, since the ratio of light incident from the side surface of the lens array to escape from the opposing side surface is high, there is a problem that the utilization efficiency of the incident light amount is low.

(5) In the method disclosed in Japanese Patent Application Laid-Open No. 63-1223, an optical coupler is formed as a V-groove as described in the document of (6), and the size of the V-groove is adjusted to obtain an output light quantity. Can be adjusted, but it is very difficult to manufacture the optical coupler, and there is a problem that the utilization efficiency of the incident light amount is reduced.

Therefore, the present invention provides an optical bus for transmitting a signal between a plurality of circuit boards, without being limited by the speed of light / electric conversion and electric / light conversion of the light receiving element and the light emitting element on each circuit board. The signal can be transmitted between the circuit boards at high speed, the light use efficiency is high, the incident signal light can be branched into the output signal light having sufficient light intensity, and the uniformity can be obtained in each circuit board. A signal light having a light intensity can be obtained, the optical bus can be reduced in size, and the optical bus can be easily manufactured.

[0015]

According to the optical bus of the present invention, a plurality of light branching means each including a light incident portion and a light emitting portion are provided for a translucent medium. Separating the signal light incident on the light incident part into two signal lights, and directing one of the signal lights toward one end of the translucent medium via the respective light emitting parts on the one end side. And the other signal light is directed toward the other end of the light-transmissive medium, and is transmitted through the respective light-emitting portions on the other end side into the light-transmissive medium. The respective light emitting portions are arranged so that the signal light portion propagating in the light transmitting medium and incident on the light emitting portion from inside the light transmitting medium is out of the light transmitting medium. The light is emitted.

[0016]

In the optical bus of the present invention constructed as described above, the optical / electrical conversion and the electric / optical conversion are not performed on the way, so that the optical / electrical conversion of the light receiving element and the light emitting element on each circuit board is performed. Signals can be transmitted between circuit boards at high speed without being limited by the speed of electrical / optical conversion. Moreover, the light use efficiency is high, and the incident signal light can be split into the output signal light having sufficient light intensity.
Signal light having a uniform light intensity can be obtained on each circuit board.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment of Signal Processing Apparatus--FIG. 1] FIG. 1 shows an embodiment of a signal processing apparatus of the present invention provided with an optical bus of the present invention.

A plurality of board connectors 3 are attached to the support board 1, and a power supply, a ground, and electric wiring for signal transmission, which are not shown in the figure, are provided.

A plate-shaped translucent medium 2 is attached to one side of one surface of the support substrate 1 along the direction in which the connectors 3 are arranged. For example, the translucent medium 2 has a refractive index of 1.51.
Is used.

A circuit board 4 is detachably mounted on each connector 3, and electrical wiring on the support board 1 is
Via the electronic circuit 4a on the circuit board 4 mounted on each connector 3.

Each circuit board 4 has a light emitting element 6 and a light receiving element 8 arranged at predetermined positions above the translucent medium 2 when the circuit board 4 is mounted on the connector 3.
The light emitting element 6 emits the signal light 5 and causes the signal light 5 to enter the light transmitting medium 2, and the light receiving element 8 receives the signal light 7 emitted from the light transmitting medium 2.

The light-transmitting medium 2 and the light-emitting element 6 and the light-receiving element 8 on each circuit board 4 will be described in the following first.
Or, as shown in the second embodiment, each circuit board 4
An optical bus 15 for transmitting an optical signal therebetween is formed.

[First Embodiment of Optical Bus ... FIGS. 2 to 1]
0] FIGS. 2A and 2B show a first embodiment of the optical bus of the present invention, wherein FIG. 2A is a top view, FIG. 2B is a sectional view taken along line AA 'of FIG. It is.

At a position on the light transmitting medium 2 facing the light emitting element 6 and the light receiving element 8 on each circuit board 4, a light branching means 10 including a diffraction element 11 and a light guide 12 is provided.

The diffraction element 11 separates the signal light 5 incident from the corresponding light emitting element 6 into two signal lights 5a and 5b, and separates the signal light 5a in the length direction (X direction) of the light transmitting medium 2.
Is bent toward the one end (left end) 2a of the translucent medium 2 at an angle α in the width direction (Y direction) of the translucent medium 2 so that the inside of the translucent medium 2 is totally reflected on the back surface and the front surface. While the signal light 5b is directed toward the other end (right end) 2b of the translucent medium 2 in the X direction and bent at an angle α in the Y direction, so that the entire inside of the translucent medium 2 is formed on the back surface and the front surface. It is assumed that the light travels while being reflected.

The light guide 12 serves to guide a part of the signal light beams 5a and 5b, which travel while totally reflecting inside the light transmitting medium 2, from the light transmitting medium 2, and have the same refractive index as that of the light transmitting medium 2. Is formed on the translucent medium 2 by printing in a strip shape. When a glass substrate having a refractive index of 1.51 is used as the translucent medium 2 as described above, for example, an acrylic resin having a refractive index of 1.51 is used as the light guide 12.

Further, a lens 13 is arranged on the light guide 12 in contact with the light guide. The lens 13 causes the signal light beams 5a and 5b derived from the light guiding member 12 to enter the corresponding light receiving element 8 as the signal light 7 and sets the focal length of the curved surface on the short side (X direction) to the light guiding member 12. And the focal length of the curved surface on the long side (Y direction) is made equal to the distance to the light receiving element 8.

An example of the diffraction element 11 and the light guide 12 is shown in FIG.
Except for the leftmost diffraction element and the rightmost diffraction element in the X direction, areas 11 of diffraction patterns different from each other
a and 11b. However, the width of the area 11a increases as the diffraction element on the right side increases (the area 11a
area 11a and area 1
The width (area) ratio of 1 b is changed for each diffraction element 11.
The leftmost diffractive element is the entire area 11b, and the rightmost diffractive element is the entire area 11a.

Thus, as shown in FIGS. 2A and 3, when the signal light 5 forms the beam spot 9 and enters the diffraction element 11, the portion of the signal light 5 incident on the area 11 a becomes: As the signal light 5a, the left end 2 of the translucent medium 2
The portion that is diffracted toward the a side and enters the area 11b of the signal light 5 is diffracted toward the right end 2b of the translucent medium 2 as the signal light 5b. The leftmost diffractive element diffracts only the signal light 5b, and the rightmost diffractive element diffracts only the signal light 5a.

As shown in FIGS. 2A and 2B and FIG. 3, the light guide 12 is provided at the position of the light branching means 10 corresponding to each circuit board 4 with the diffraction element 11 and the beam formed thereon. The position in the X direction with respect to the spot 9 is sequentially shifted. That is, the leftmost light guide is formed at the leftmost position of the leftmost diffractive element, and the rightmost light guide is formed at the rightmost position of the rightmost diffractive element.

In the optical bus having the above-described structure, the pulsed signal light 5 is emitted from the light emitting element 6 on a certain circuit board 4, and the diffraction element 11 of the corresponding light splitting means 10 on the light transmitting medium 2 is emitted. Then, a beam spot 9 is formed and incident, and a portion overlapping the area 11a of the beam spot 9 is diffracted as signal light 5a, and a portion overlapping the area 11b of the beam spot 9 is diffracted as signal light 5b.

The diffracted signal light 5a is bent toward the left end 2a of the translucent medium 2 in the X direction and bent at an angle α in the Y direction, and travels while totally reflecting inside the translucent medium 2, The beam spot S is located near the light guide 12 of the light branching means 10 on the left.
a is formed. Similarly, the diffracted signal light 5b is bent at an angle α in the Y direction toward the right end 2b of the translucent medium 2 in the X direction, and travels while being totally reflected inside the translucent medium 2, A beam spot Sb is formed near the light guide 12 of the light branching means 10 on the right.

The portion of the signal light 5a or 5b where the beam spot Sa or Sb overlaps with the light guide 12 is led out of the light transmitting medium 2 toward the lens 13 by the light guide 12 and the beam spot Sa or Sb is output. The portion where Sb does not overlap with the light guide 12 is not guided out of the light transmissive medium 2 and proceeds while being totally reflected inside the light transmissive medium 2, and further proceeds to the left or right adjacent light splitting means 10. A beam spot is formed near the light guide 12.

Since the focal length of the short side curved surface of the lens 13 is equal to the distance to the light guide 12, the signal light 5 from the left and right
b and 5a emit the lens 13 in parallel with each other, and since the focal length of the long side curved surface of the lens 13 is equal to the distance to the light receiving element 8, the signal light 5 from the light emitting element 6 on any circuit board 4 Is also bent toward the light receiving element 8.
Therefore, the signal lights 5 a and 5 b derived from the translucent medium 2 enter the light receiving element 8 as the signal light 7 for each circuit board 4 and are received by the light receiving element 8.

As described above, in the above-described optical bus, the light-to-electric conversion and the electric-to-light conversion are not performed on the way, and therefore, the light receiving element 8 and the light emitting element 6 on each circuit board 4 are not required.
Signals can be transmitted between the circuit boards 4 at high speed without being restricted by the speed of the optical / electrical conversion and the electrical / optical conversion.

In addition, the optical coupling between the circuit boards 4 is not optical coupling via a free space, but a translucent medium 2 is used, and a half mirror is used as the optical branching means 10, or an optical fiber line is used. Since the diffractive element 11 and the light guide 12 are formed on the translucent medium 2 instead of arranging the V-groove optical coupler, the light use efficiency is high, and the incident signal light 5 is converted to a light having sufficient light intensity. The signal light 7 can be branched into the outgoing signal light 7, the signal light 7 having a uniform light intensity can be obtained in each circuit board 4, the optical bus can be reduced in size, and the optical branching means 10 can be easily manufactured. can do. Of course, there is no occurrence of data transmission failure or signal transmission failure.

FIGS. 2 and 3 show the case where the angle α is constant and the light guides 12 of the light branching means 10 corresponding to the respective circuit boards 4 are formed as one piece. Is changed in several ways, and the light guides 12 of the light branching means 10 corresponding to the respective circuit boards 4 are respectively incident on the diffraction elements 11 of the other light branching means 10 and the signal light 5 diffracted.
a or 5b may be formed as a plurality of parts, each of which is individually derived.

For example, when six circuit boards 4 are mounted on the support board 1 as shown in FIG. 1, as shown in FIG. 4, the positions of the optical branching means corresponding to each circuit board are N1, N
2... N6, the angle α of the area 11a of the diffraction element 11 at the positions N2, N4, and N6 and the area 11b of the diffraction element 11 at the positions N1, N3, and N5 is α1.
The angle α of the area 11a of the diffraction element 11 at the position N3 and the area 11b of the diffraction element 11 at the position N4 is α2, and the area 1 of the diffraction element 11 at the position N5 is
The light derivation for deriving the signal light 5b incident on the area 11b of the diffraction element 11 at the position N1 and diffracted at the positions N2 to N6, where α3 is the angle α with respect to the area 11b of the diffraction element 11 at the position N1 and the position N2. As shown by shading the body 12, the light deriving bodies 12 at the positions N1 to N6 individually derive the diffracted signal light 5a or 5b by being incident on the diffractive element 11 at other positions. Formed as divided.

In this way, the signal lights 5a and 5b
Can propagate the signal lights 5 a and 5 b into the translucent medium 2 without interference by the light guide 12. The thickness of the translucent medium 2 is 10 mm, and the pitch of the circuit board 4 is 10
mm and the beam spot size on the diffraction element 11 is 2
mm (long axis) x 1 mm (short axis), the angle α
1, α2 and α3 are 11.3 °, 31.0 °,
It may be 38.7 °. The diffraction angle of the signal light beams 5a and 5b in the thickness direction of the translucent medium 2 may be 45 °.

The beam spot 9 of the signal light 5 has a Gaussian distribution light intensity distribution as shown in FIG. Therefore, in the example of FIG. 3 or FIG. 4, the ratio of the width (area) of the area 11a and the area 11b of each diffraction element 11 is 0: 5.
When the width of the light guide 12 corresponding to each diffractive element 11 is made uniform by changing linearly such as 1: 4, 2: 3, 3: 2, 4: 1, and 5: 0, each light emitting portion ( The intensity of the signal light 7 obtained at each emission position varies.

Therefore, for example, as shown in FIG.
When six circuit boards 4 are mounted on the beam spot 9, as shown in FIG. 5, the beam spot 9 is divided into five areas Ea, Eb, Ec, Ed, and Ee where the respective light intensities are equal to each other. As shown, the signal light incident on the diffractive element 11 at the position N1 and diffracted is the regions Ea, Eb, Ec, Ed, E of the beam spot 9 on the diffractive element 11 at the position N1.
e, the signal light portions from the positions N2, N3, N
As shown in FIG. 7, each of the signal lights derived from the light deriving bodies 12 of N4, N5, and N6 and incident on and diffracted from the diffraction elements 11 at the other positions N2 to N6 is similarly set. Areas 11a and 11b of the diffraction element 11 are formed, and the position and width of the light guide 12 corresponding to each diffraction element 11 are set. FIG. 7 shows a case where the angle α is set in the same manner as in the example of FIG.

According to the examples shown in FIGS. 6 and 7, the intensity of the signal light 7 obtained at each of the emission sections becomes substantially uniform. FIG. 8 shows positions N2 to N5 when the signal light 5 is incident on the diffraction element 11 at the position N1 and the signal light 7 is emitted from the light guide 12 at the positions N2 to N6 in the examples of FIGS. The relative output intensity at N6 is shown, and the variation of the output intensity is 10% or less.

As another example, as shown in FIG. 9, the beam spot 9 is divided into 15 regions of uniform width, and the position N
Regarding the signal light incident on the first diffraction element 11 and diffracted, the signal light portions from the first, sixth, and eleventh regions are located at positions N
The signal light portions from the three non-adjacent regions are respectively derived from the three divided light guides 12 at positions N2 to N6.
In the same manner, the signal light, which is derived from and is incident on the diffractive elements 11 at the other positions N2 to N6 and diffracted, forms areas 11a and 11b of each diffractive element 11 so that The corresponding position and number of light guides 12 (3 in FIG. 9) are set.

According to this example, the signal light 7 obtained at each emission part is obtained by synthesizing the signal light portion from the region where the intensity of the beam spot 9 is low and the signal light portion from the region where the intensity is high. Therefore, as in the examples of FIGS. 6 and 7, the intensity of the signal light 7 obtained at each emission unit becomes substantially uniform. FIG. 10 shows positions N2 to N6 when the signal light 5 is incident on the diffraction element 11 at the position N1 and the signal light 7 is emitted from the light guide 12 at the positions N2 to N6 in the example of FIG.
Indicates the relative emission intensity, and the variation of the emission intensity is 1
0% or less. However, the number of regions of the beam spot 9 and the number of divisions of the light guide 12 for one emission unit are
It is desirable to set it to 3 or more.

[Second Embodiment of Optical Bus ... FIGS. 11 to 1
4] FIG. 11 shows a second embodiment of the optical bus of the present invention.

As shown in FIG. 1, six connectors 3 are attached to the support substrate 1, a translucent medium 2 is attached to one side of one surface of the support substrate 1, and a light emitting element is attached to each connector 3. The circuit board 4 on which the light receiving element 6 and the light receiving element 8 are mounted is mounted.

The portions of the light emitting elements 6 on each circuit board 4 are input portions M1, M2,.
11 are output units N1, N2... N6,
(A) and (B) are side views when the signal light 5 is incident on the translucent medium 2 from the input units M2 and M4, respectively, and FIG.
(C) is a top view when the signal light 5 is incident on the translucent medium 2 from the input unit M4.

In this embodiment, a light splitting means 20 comprising a prism array 21 and a cutout portion 22 is provided at a position on the light transmitting medium 2 facing the light emitting element 6 and the light receiving element 8 on each circuit board 4.

The prism array 21 is provided so that the position of the translucent medium 2 in the width direction (Y direction) is sequentially shifted by the width for each corresponding light emitting element 6, and the signal light 5 incident from the corresponding light emitting element 6 is provided. Separated into two signal lights 5a and 5b,
The signal light 5a is directed to one end (left end) 2a of the light-transmitting medium 2 in the length direction (X direction) of the light-transmitting medium 2, and is bent in the light-transmitting medium 2 without bending in the Y direction. The signal light 5b is made to travel while being totally reflected by the front surface, and the signal light 5b is directed to the other end (right end) 2b of the light transmissive medium 2 in the X direction. It is assumed that the light is advanced while being totally reflected by the surface.

The notch 22 is for guiding a part of the signal light beams 5a and 5b, which travel while being totally reflected in the translucent medium 2, from the translucent medium 2. For those corresponding to the output portions N2 to N5, two are formed on both sides of the corresponding prism array 21, and for those corresponding to the output portion N1 or N6, one are formed on the right or left side of the corresponding prism array 21. I do.

Prism array 21 and notch 22
Further, FIG. 12 (FIG. 12A is a side view,
(B) is a top view, (C) is another side view),
Except for the leftmost prism array and the rightmost prism array in the X direction, the prism array 21 includes prisms 21a and 21b having different directions from each other. However, the right prism array is prism 2
The ratio of the numbers of the prisms 21a and 21b is changed for each prism array 21 so that the number of 1a increases (the number of prisms 21b decreases). The leftmost prism array includes only the prism 21b, and the rightmost prism array includes only the prism 21a.

That is, the ratio between the number of prisms 21a and the number of prisms 21b in each prism array 21 is determined by the input unit M
1, M2, M3, M4, M5, M6 in the order of 0: 5
1: 4, 2: 3, 3: 2, 4: 1, 5: 0.

As shown in FIGS. 12A and 12B, when the signal light 5 forms the beam spot 9 and enters the prism array 21, the prism 21 of the signal light 5
a portion of the signal light 5a traveling toward the right end of the light transmitting medium 2 is separated as a signal light 5a traveling toward the left end of the light transmitting medium 2.
Is separated as The leftmost prism array separates only the signal light 5b, and the rightmost prism array separates only the signal light 5a.

The width of the notch 22 in the X direction is the number of circuit boards 4 connectable to the translucent medium 2 (6 in FIG. 11).
And the size of the beam spot 9.

Further, as shown in FIGS. 12A and 12C, a lens 23 is disposed on the cutout portion 22. The lens 23 causes the signal light beams 5a and 5b derived from the cutout portion 22 to enter the corresponding light receiving element 8 as the signal light 7 and has a focal point on the light receiving surface of the light receiving element 8.

In the optical bus having the above-described configuration, the pulse-like signal light 5 is emitted from the light-emitting element 6 on a certain circuit board 4, and the prism array 21 of the corresponding light splitting means 20 on the translucent medium 2. To form a beam spot 9 and enter
A portion of the beam spot 9 overlapping with the prism 21a is separated as the signal light 5a, and the prism 2 of the beam spot 9 is separated.
The portion overlapping 1b is separated as signal light 5b.

The separated signal light 5a travels toward the left end 2a of the translucent medium 2 in the X direction without being bent in the Y direction while being totally reflected inside the translucent medium 2 to be adjacent to the left. A beam spot is formed in the vicinity of the notch 22 of the light branching means 20 of FIG. Similarly, the separated signal light 5b travels toward the right end 2b of the translucent medium 2 in the X-direction and without being bent in the Y-direction while totally reflecting inside the translucent medium 2,
A beam spot is formed in the vicinity of the notch 22 of the light splitting means 20 on the right side.

The portion of the beam spot of the signal light 5a or 5b that overlaps the notch 22 is the notch 2
2 and the lens 23, the portion that is derived from the light-transmitting medium 2 toward the light-receiving element 8 and does not overlap with the notch 22 of the beam spot of the signal light 5 a or 5 b is not extracted from the light-transmitting medium 2. Further, the laser beam proceeds while being totally reflected in the translucent medium 2, and further forms a beam spot near the cutout portion 22 of the adjacent light branching means 20 on the left or right side.

Since the lens 23 has a focal point on the light receiving surface of the light receiving element 8, the signal light 5 from the light emitting element 6 on any circuit board 4 changes its direction toward the light receiving element 8. Therefore, the signal lights 5a and 5b derived from the translucent medium 2 are converted into signal lights 7 for each circuit board 4 as light receiving elements 8
And is received by the light receiving element 8.

In the optical bus according to the second embodiment, similarly to the optical bus according to the above-described first embodiment, no optical / electrical conversion and electric / optical conversion are performed on the way, and therefore Signals can be transmitted between the circuit boards 4 at high speed without being restricted by the speed of the light / electric conversion and the electric / light conversion of the light receiving element 8 and the light emitting element 6.
Light utilization efficiency is high, the incident signal light 5 can be split into outgoing signal light 7 having sufficient light intensity, and the signal light 7 having uniform light intensity can be obtained in each circuit board 4. The bus can be reduced in size, and the optical branching means 20 can be easily manufactured.

FIG. 12 shows an example in which the ratio of the number of prisms 21a and 21b of each prism array 21 is changed, but the width of each of the prisms 21a and 21b is made uniform. Since FIG. 9 shows the light intensity distribution as shown in FIG. 5, the beam spot 9 is divided into a plurality of regions where the respective light intensities are equal, as shown in FIG. The width of the beam spot 9 may be made equal to the width of each divided area of the beam spot 9. According to this, the intensity of the signal light 7 obtained at each emission unit becomes substantially uniform.

In this embodiment, the thickness of the translucent medium 2 is 5 mm, the width is 3 mm, the pitch of the circuit board 4 is 11 mm, and the beam spot size on the light branching means 20 is 5 mm.
(Long axis) × 0.5 mm (short axis)
When the notch 22 is provided with a lens, the notch 22 has a length of 3 mm in the width direction of the translucent medium 2, a width of 1 mm in the length direction of the translucent medium 2, a vertex angle of 90 °, and a prism array. 21
Is formed by integrally forming a lens for collimating a light beam from a high-refractive material having a refractive index of 1.93, and setting the apex angle of each of the prisms 21a and 21b to 60 °, thereby separating the separated signal light. The angles of 5a and 5b with respect to the back and front surfaces of the translucent medium 2 are 45 °.

FIG. 14 shows that in this embodiment, the signal light 5 is made incident from the input sections M1, M2, M3, respectively, and the output sections N2 to N6, the output sections N1, N3 to N6, and the output sections N1, N2, N4 respectively. -N6 indicates the relative emission intensity at each emission position when the signal light 7 is emitted,
The variation of the emission intensity is 10% or less.

[0064]

As described above, according to the present invention, the signal between each circuit board is not restricted by the speed of light / electric conversion and electric / light conversion of the light receiving element and the light emitting element on each circuit board. High-speed transmission, high light use efficiency, the incident signal light can be split into the outgoing signal light of sufficient light intensity, and the signal light of uniform light intensity can be obtained in each circuit board. In addition, the optical bus can be downsized, and the optical bus can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a signal processing device of the present invention.

FIG. 2 is a diagram showing a first embodiment of the optical bus of the present invention.

FIG. 3 is a diagram illustrating an example of a diffraction element and a light guide.

FIG. 4 is a diagram showing another example of the diffraction element and the light guide.

FIG. 5 is a diagram showing a light intensity distribution of a beam spot.

FIG. 6 is a diagram showing still another example of the diffraction element and the light guide.

FIG. 7 is a view showing still another example of the diffraction element and the light guide.

FIG. 8 is a diagram showing relative emission intensities at respective emission positions in the examples of FIGS. 6 and 7;

FIG. 9 is a view showing still another example of the diffraction element and the light guide.

FIG. 10 is a diagram showing a relative emission intensity at each emission position in the example of FIG. 9;

FIG. 11 is a diagram showing a second embodiment of the optical bus of the present invention.

FIG. 12 is a diagram illustrating an example of a prism array and a cutout portion.

FIG. 13 is a diagram showing another example of the prism array.

FIG. 14 is a diagram showing a relative emission intensity at each emission position in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Support board 2 ... Translucent medium 3 ... Connector 4 ... Circuit board 4a ... Electronic circuit 5, 5a, 5b ... Signal light 6 ... Light emitting element 7 ... Signal light 8 ... Light receiving element 9 ... Beam spot 10 ... Light branching means DESCRIPTION OF SYMBOLS 11 ... Diffraction element 11a, 11b ... Area 12 ... Light guide 13 ... Lens 20 ... Light splitting means 21 ... Prism array 21a, 21b ... Prism 22 ... Notch part 23 ... Lens

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Hamada 430 Sakai Nakaicho, Ashigara-gun, Kanagawa Prefecture Inside Green Tech Nakai Fuji Xerox Co., Ltd. (72) Inventor Hidenori Yamada 430 Border, Nakai-cho, Ashigara-gun, Kanagawa Prefecture Green Tech Nakai Fuji Xerox Co., Ltd.F-term (reference)

Claims (8)

[Claims] 1. A plurality of light splitting means each comprising a light incident portion and a light emitting portion are provided for a translucent medium, and each of the light incident portions transmits signal light incident on the light incident portion. The signal light is separated into two signal lights, and one of the signal lights is directed toward one end of the light-transmitting medium, and propagates into the light-transmitting medium via the respective light emitting portions on the one end side. The other signal light is directed to the other end of the light-transmitting medium, and propagates into the light-transmitting medium via the respective light-emitting portions on the other end. An optical bus, wherein the emission unit is configured to emit a signal light portion that propagates in the light transmitting medium and enters the light emitting unit from inside the light transmitting medium to outside the light transmitting medium. 2. The optical bus according to claim 1, wherein said respective light incident portions and said respective light emitting portions are provided on the same surface of said translucent medium. 3. The optical bus according to claim 1, wherein the one and the other signal lights propagate while being totally reflected in the light transmitting medium. 4. The optical bus according to claim 1, wherein each of the light incident portions is a diffractive element, and the one and the other signal lights are bent in a width direction of the translucent medium. bus. 5. The optical bus according to claim 1, wherein each of said light incident portions is a prism array. 6. The optical bus according to claim 1, wherein each of the light emitting portions is a light guide formed on the translucent medium. 7. The optical bus according to claim 1, wherein each of the light emitting portions is a cutout formed in the translucent medium. 8. An electronic circuit for generating an electric signal,
And a transmission unit having an element for converting the generated electric signal to an optical signal and emitting the same, an element for converting an incident optical signal to an electric signal, and an electronic circuit for processing the converted electric signal. A plurality of circuit boards on which at least one of the plurality of circuit boards is mounted; and the optical bus according to any one of claims 1 to 7, wherein the plurality of circuit boards are optically coupled to at least one of the transmission unit and the reception unit. A signal processing device comprising: