JPH03265823A - Optical spatial connecting method between packaged substrates - Google Patents

Abstract

PURPOSE:To obtain small-sized optical spatial connections with the large degree of freedom by applying an optical path converting function with polarization control to the connection part between the packaged substrates. CONSTITUTION:Light emitting element modules (1-1)-(1-4) which emit a single polarized parallel light are constituted by uniting light emitting elements, lenses, and polarizers and light receiving element modules (2-1)-(2-3), (3-1)-(3-3), (4-1) - (4-3), and (5-1) - (5-3) are constituted by uniting light receiving elements and lenses. Then signal light emitted by one light emitting element module has its plane of polarization controlled and also has its path converted depending upon the plane of polarization on its path. Consequently, elements on an optional packaged substrate 1 and the light receiving element modules can be coupled. Consequently, the light emitting elements and light receiving elements can be decreased in number and the small-sized optical spatial connections with the large degree of freedom are obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical space interconnection method for transmitting and receiving signals between mounting boards (wiring boards) in an electronic device using a light beam propagating in space. In particular, the present invention relates to an optical spatial connection method between mounting boards that aims to reduce the number of two light emitting elements and two light receiving elements and realize a compact optical spatial connection with a large degree of freedom.

[Conventional technology]

When it is necessary to send and receive signals between a plurality of boards (mounted substrates) mounted in an electronic device, it is necessary to provide wiring for signal sending and receiving between these boards. Conventionally, such inter-boat wiring was performed electrically. However, as devices become larger, the number of boards increases, and the speed of transmitted and received signals increases, inductance, stray capacitance, and electromagnetic induction generated in these electrical wirings have become problems. As a wiring method to solve these electrical wiring problems, an optical spatial wiring method has been proposed in which a parallel light beam propagating in space is used as a signal transmission medium (Noro et al., ``Multilayer Optical Wiring Board'').

(Patent Application No. 1983-206473).

FIG. 6 shows an explanatory diagram disclosed in the above proposal, and is an example in which connections between a plurality of boards (five in the illustrated example) are realized by the optical space connection method. In FIG. 6, 1 integrates a light emitting element and a lens.

a light emitting element module that converts signals generated on each mounting board 1-1 to 11-5 into a parallel light beam and radiates it into space; 2;
is a photodetector module that integrates a photodetector and a lens,
3 each represents a window for passing a parallel light beam. That is, (N-1,) light emitting elements and (N-1) light receiving elements are provided on each surface of N (N22) boards.

Another third.
If there is a fourth board (this may be ↓ or multiple), by providing a window that allows the light to pass through the third and fourth boards, it is possible to It is possible to exchange signals between any two boards among the boards.

[Problem to be solved by the invention]

In the optical space connection method according to the proposed technology described in 1., it is necessary to arrange on each board the same number of light emitting element modules and light receiving element modules as the number of boards to be connected.

That is, if the number of boards is N, then N(N-1) light emitting element modules and N(N-1) light receiving element modules are required. Therefore, as the number of boats increases,
Light emitting element module and light receiving element module on each boat.

The number of opto-electric conversion circuits connected to these modules also increases, and the power consumption of the optical space connection section increases.

There were problems such as an increase in the proportion of the board area occupied by the optical space connection section.

The purpose of the present invention is to solve the above-mentioned problems in the prior art.
It is an object of the present invention to provide an optical spatial connection method between mounting boards that can reduce the number of light emitting elements and light receiving elements, increase the degree of freedom in connection, and reduce the size of the connection part.

[Means to solve the problem]

In order to achieve the above object, there are two aspects of the present invention.

The following optical space connection method is used. Namely.

In the optical space connection method, which uses parallel light propagating in space to exchange signals between a plurality of N (N22) mounted boards, electrical signals are converted into signal light with only linearly polarized components on the surface of each mounted board. One light-emitting element that emits the signal light into space, and N-1 light-receiving elements that convert the incident signal light into an electrical signal are provided.

A polarization plane control element that rotates the polarization plane of the signal light passing twice on the path of the signal light from each light emitting element by an arbitrary angle under external control; an optical path converting element having a reflecting surface that transmits the P polarized light component parallel to the plane created by the plane, and reflects the perpendicular S polarized light component by changing its course by a right angle; A reflecting element is provided which rotates the polarization plane of the signal light that has advanced by 90 degrees and moves it backward toward the reflecting surface, and a polarization plane control element is also arranged between each optical path conversion element, and these polarization planes are rotated by 90 degrees. By controlling the rotation angle of the polarization plane with the control element, the signal light from the light emitting element of any mounting board is first changed by a right angle with the optical path conversion element for the own mounting board, and then the optical path for the other mounting board is changed. By making the incident light enter the element, and then changing the path by a right angle in the optical path conversion element that takes in the incident light and emitting it toward the light receiving element of the mounting board to be connected, optical space connection can be made between arbitrary mounting boards. This is the method to do so.

[Effect]

The main feature of the present invention is that the number of light emitting elements is reduced by applying the optical path conversion function by polarization control to the connection section between the mounting boards, and a compact optical space connection with a large degree of freedom is realized. This point clearly differs from the prior art.

〔Example〕

The present invention will be explained in detail with reference to the following two drawings.

Example 1 FIG. 1 shows an explanatory diagram of the optical path of the first example of the present invention, and
The figure shows a three-dimensional perspective view. In addition, in the first engineering drawing,
To facilitate the explanation of light paths.

The light emitting element and light receiving element in FIG. 2 are rotated by a right angle and are shown facing the optical path changing element. This embodiment is an example in which connection between any two of four mounting boards is realized. ]-1 to 1-4 are light emitting element modules that integrate a light emitting element, a lens, and a polarizer and emit a single polarized parallel light beam; 2-l to 2-3. :3-1~3-3
．． 4-1 to 4-3. 5-1 to 5-3 are light receiving element modules that integrate a light receiving element and a lens, 6-1 to 6-4 are polarizing beam splitters, and 7-1 to 7-4 are 1/ 4 wavelength plate,
8-Sat to 8-4 represent total reflection mirrors, respectively. A polarizing beam splitter transmits the polarized light component (P polarized light component) parallel to the plane formed by the normal line of the two reflecting surfaces and the incident parallel light,
The vertical component (S-polarized component) is an element that reflects the incident light in a direction perpendicular to it. 9-King~9-4.10-1~10
-3 is a polarization plane control element, specifically a liquid crystal switch.

Examples include ferroelectric switches. Also 111-11
-4 is a mounting board, and 2 is an optical path for transmitting a signal from the mounting board 1172 to 11-4.

Symbols 3 each represent an optical path when transmitting a signal from the mounting board 11-3 to the mounting board 11-1. The light-emitting element modules and light-receiving element modules on each mounted board are arranged one-dimensionally or two-dimensionally on the same plane, and their number is (N-1) on the upper side, where N is the total number of mounted boards. be.

The operation of this embodiment will be explained by taking as an example the case where a signal is transmitted from the mounting board 11-2 to 1↓-4, and the case where the signal 1-1-8 is transmitted from the mounting board 1↑-3. First, a case will be described in which a signal is transmitted from the knee 2 of the mounting board 1 to the knee 11-4. The electrical signal output from the mounting board 112 is converted into a single polarized parallel light beam E2 by the light emitting element module J--2, and is radiated into space. parallel light beam 1
2 is converted into S-polarized light by the polarization plane control element 9-2 and enters the polarization beam splitter 6-2. Since the signal light 12 incident on the polarizing beam splitter 6-2 has only an S-polarized component, the optical path is changed downward in the figure at right angles to the incident light, and the signal light 12 is emitted and enters the polarization plane control element 10-2. The polarization plane control element 10-2 rotates the polarization of the signal light 12 by 90 degrees, and
Emit as polarized light. The signal light 12 converted into P-polarized light passes through the polarization beam splitter 6-3 as it is, and enters the polarization plane control element 10-3. Polarization plane control element 10-3
rotates the polarization of the signal light by 90 degrees again.

Convert to S polarized light. Therefore, the signal light 12 is reflected in the right angle direction by the polarizing beam splitter 6-4, and the polarized light is rotated by 90 degrees after passing through the long plate 7-4, converted into P-polarized light, and polarized again. The beam is incident on the beam splitter 6-4. Since the signal light beam 2 has been converted into P-polarized light, it passes through the polarization beam splitter 6-4 as it is and is emitted to the left in FIG. The emitted signal light 12 is sent to the light receiving element module 5-
2, it is converted into an electrical signal and guided to the mounting board 11-4. Next, a case will be described in which a signal is transmitted from the mounting board 1-3 to the workpiece 1-1. The electrical signal output from the mounting board 11-3 is sent to the light emitting element module 1-3.

The polarization plane control element 9-3 causes the light to enter the polarization beam splitter 6-3 as a P-polarized parallel light beam. The input signal light 13 is transmitted to the polarizing beam splitter 6-3. ]]/
4 wavelength Wavelength 77 Gray 39 Reflected by splitter 6-3 4
The light is emitted upward in the figure. The polarization of the output signal light 13 is converted into P polarization by the polarization plane control element 10-2 and into S polarization by the polarization plane control element 10-1, and finally the signal light 13 is reflected by the polarization beam splitter 6-1 and sent to the light receiving element module 2-. 2. The light receiving element module 2-2 converts the signal light into an electrical signal and outputs it to the mounting board 11-1. As explained above, the signal light emitted from the two-light emitting element module can be arbitrarily changed by polarization control (switching between P-polarized light and S-polarized light) and path conversion depending on these polarization planes in the middle of its path. It is possible to combine with a light receiving element module on a mounting board. Therefore, according to this embodiment, the number of light emitting element modules and light emitting element driving electronic circuits is
It is now possible to reduce the number of electronic circuits to 1/(N-1) of the conventional number, and the number of electronic circuits related to optical spatial connections on the mounting board.
The optical system will be made smaller.

Example 2 An explanatory diagram of the optical path of the second embodiment of the present invention is shown in FIG.

In the first embodiment of the present invention, the polarization plane control element is used for S-polarized light,
Used as a switch for P-polarized light.

One-to-one connection between arbitrary mounting boards is realized. In the configuration of the first embodiment of the present invention, if the polarization plane control element has a function of rotating the polarization plane of incident light by an arbitrary angle, broadcast type connection is possible with the same configuration as in FIG. 1. An arbitrary angle rotation of the plane of polarization can be realized by adjusting the voltage applied to a ferroelectric switch, for example. FIG. 3 shows a second embodiment of the present invention that allows broadcast type connection. The configuration is the same as that in Fig. 1, except that polarization plane control elements (22-1- to 224, 23
-1 to 23-3) is used, which is different from Fig. 1. Reference numeral 24 indicates an optical path in the case of broadcast type connection from the mounting board 11-2 to all other mounting boards. Mounting base 4fi. 1.
The electrical signal No. 1 outputted from the light emitting element module 1-2 is converted into a single polarized parallel light beam 24 and radiated into space. The parallel light beam 24 is converted by the polarization plane control element 22-2 into a polarization plane having an angle of 30 degrees with the S polarization plane, and enters the polarization beam splitter 6-2.

The signal light 24 incident on the polarization beam splitter 6-2 is S
Contains polarized light components and P-polarized light components at a ratio of 2:l,
The S-polarized light component is emitted downward in the figure, and the P-polarized light component is emitted upward in the figure. The signal light emitted upward has its polarization plane rotated by the polarization plane control element 23-1 so that it becomes S-polarized light, is reflected by the polarization beam splitter 6-]-, and is guided to the light-receiving element module 21-. The polarization plane of the light emitted downward in the figure is converted by the polarization plane control element 23-2 so that it forms an angle of 45 degrees with the S-polarized light. The converted signal light has a P polarization component and an S polarization component in a ratio of ]:Y. Therefore, the polarizing beam splitter 6-3 outputs the P-polarized component of the incident light as it is in the direction shown in the figure, and guides the 2S-polarized component to the light-receiving element r-4-2. Polarized light having only P-polarized light component 2 The light emitted from the beam splitter 6-3 is converted into S-polarized light by the polarization plane control element 23-3, and guided to the light receiving element module 5-2. From the above, 9 light emitting element modules 1
This means that the signal light emitted from -2 is coupled to all other light receiving element modules. In this way, by using the configuration shown in FIG. 3, it is possible to realize a broadcast type connection in which the output signal light of any mounting board is coupled to the light receiving elements on all other mounting boards.

Of course, one-to-one connection between arbitrary mounting boards is also possible using the configuration of this embodiment. Therefore, according to this embodiment, it is possible to easily switch the connection form (one-to-one connection, broadcast type connection) and switch the connection terminal by external control, and it is possible to easily realize the switching of the connection form (one-to-one connection, broadcast type connection) and the connection terminal by external control. The degree of freedom in wiring has been greatly improved compared to the previous version.

Embodiment 3 An explanatory view of the optical path of a third embodiment of the present invention is shown in FIG. 4, and a three-dimensional perspective view is shown in FIG. 14-1 to 14-4 are quarter-wave plates for light reception, 15-1 to 1-5-4 are total reflection mirrors for light reception, and 16-1 to 16-4 are quarter-wave plates for light emission.]
- ] 7-1 to 17- are total reflection mirrors for light emission, 18-1 to
1-8-4 represents a condenser lens, and 19-1 to 19-4 represent light receiving elements, respectively. The positional relationship between these condensing lenses and the light receiving elements is such that each light receiving element is arranged at a lens focal position on the optical axis of each condensing lens. 20 again
is the optical path when transmitting a signal from the light emitting element 1-2 to the light receiving element 1-9-4, and 2]- is the optical path from the light emitting element 13 to the light receiving element t.
Each shows an optical path when transmitting a signal to 9-1. In this example, a reflection element consisting of a quarter-wave plate and a total reflection mirror is arranged separately for light emitted from the light emitting element module and for light incident on the light receiving element, and This embodiment differs from the first embodiment in that light is coupled to one light receiving element via a condensing lens. In this embodiment as well, the first aspect of the present invention. It is possible to realize the same functions as in the second embodiment, and moreover, both the number of light emitting elements and the number of light receiving elements can be set to N for the total number of mounted boards N. Therefore, the optical spatial connection of this embodiment can significantly reduce the proportion of the mounting board area occupied by the optical spatial connection section.

In addition, in the method of the third embodiment, each mounting board has one two-light emitting element, but the arrangement position in the -dimensional direction must be shifted sequentially for each board as shown in Figure 7. In this respect, the number of mounting boards that can be interconnected is limited. On the other hand, the positions where the two light emitting elements can be placed are arranged in a two-dimensional matrix of mXn (m and n are each 1 or more and m+n is 3 or more), and the radiation signal lines from the two light emitting elements are connected between each mounting board. By avoiding overlapping and dividing the reflecting elements accordingly, the light receiving element side remains configured to receive signal light into one light receiving element via a condensing lens, resulting in a total of m x n pieces. This makes it possible to interconnect the mounting boards, greatly increasing the degree of freedom in connection.

Further, the above-described two-dimensional arrangement method is also applicable to the above-described first and second embodiments of the present invention.

It can be applied to mutual connection when a large number of mounting boards are mounted, and a great effect can be exhibited.

5 16 The above-mentioned embodiments are applicable not only to interconnections between mounted boards, but also to optical output elements (surface-emitting lasers, array light-receiving elements,
It can also be applied to connections between optical bistable devices (optical bistable devices, etc.).

〔Effect of the invention〕

As explained above, according to the present invention, by applying the optical path conversion function by controlling the rotation angle of the polarization plane to the connection section between the mounting boards, N -While it was necessary to provide one light emitting element and N-l light receiving elements on each mounting board, 5
According to the method of claim J of the present invention, the number of light emitting elements can be set to two on the upper side of each mounting board, and according to the method of claim 2, the number of light receiving elements can also be set to one on each mounting board. This has the effect of making it possible to downsize the optical space connection section and increase the degree of freedom in connection.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the optical path of the first embodiment of the present invention. FIG. 2 is a three-dimensional perspective view of the embodiment shown in FIG. FIG. 3 is an explanatory diagram of the optical path according to the second embodiment of the present invention. FIG. 4 is an explanatory diagram of the optical path of the third embodiment of the present invention. FIG. 5 is a three-dimensional perspective view of the third embodiment. FIG. 6 is a perspective view showing the prior art. <Explanation of symbols> 6 Polarizing beam splitter 7・174 wavelength plate 8 Total reflection mirror 9.10・
... Polarization plane control element work 1 - Mounting board 14 - 174 wavelength plate for light reception 15 - Total reflection mirror for light reception ↓ 6 - 174 wavelength plate for light emission] 7 - Total reflection mirror for light emission 18 - Condensing lens ○ mark/light emitting element module ■ mark light receiving element module

Claims (1)

[Claims] 1. In an optical space connection method in which signals are exchanged between a plurality of N (N≧2) mounted boards using parallel light propagating in space,
On the surface of each mounting board, there is one light-emitting element that converts an electrical signal into signal light with only linearly polarized components and radiates it into space, and N-1 light-receiving elements that convert the incident signal light into an electrical signal. On the path of the emitted signal light from each light emitting element, there is a polarization plane control element that rotates the polarization plane of the passing signal light by an arbitrary angle under external control, and a polarization plane control element that rotates the polarization plane of the signal light passing through it by an arbitrary angle, and An optical path converting element has a reflecting surface in which polarized light components parallel to the plane formed by the normal line of the reflecting surface are transmitted, and perpendicular polarized light components are reflected by changing their course by a right angle. A reflection element is provided to rotate the polarization plane of the signal light traveling in a direction parallel to the light by 90 degrees and reverse the polarization plane toward the above-mentioned reflecting surface, and a polarization plane control element is also provided between each of the above-mentioned optical path conversion elements. The polarization plane rotation angle of these polarization plane control elements is controlled externally, and the signal light from any light emitting element is first changed by a right angle using an optical path conversion element for the own mounting board, and then transferred to another mounting board. By making the incident light enter an optical path converting element for the board, and then changing the course by a right angle again in the optical path converting element that takes in this incident light, and emitting it toward the light receiving element on the mounting board to be connected, it can be applied to any mounted board. An optical space connection method between mounted boards, which is characterized by optical space connection between them. 2. The number of light-receiving elements provided on the mounting board according to claim 1 is one for each mounting board, and the reflecting element is a part that receives signal light from a light-emitting element and reflects incident light to the light-receiving element. and a condenser lens is provided between the optical path converting element and the light receiving element so that each light receiving element is disposed at a focal position on the optical axis of each condensing lens. An optical spatial connection method between mounted boards, which is characterized by: