JPS6350897B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical signal transmission device that transmits signals from a rotating body side to a stationary side in a non-contact manner.

Conventionally, as means for transmitting information obtained on the rotating body side to the stationary side, a contact method using a slip ring, a non-contact method using radio waves, or sound waves have been used. The former has many problems in terms of lifespan and noise generation, while the latter requires a complicated device and inevitably increases in size.

On the other hand, a device has already been proposed in which a light emitting diode is attached to the rotating body and a signal is transmitted to the light receiving diode on the stationary side via an optical guide.

However, with this type of device, there are extremely difficult manufacturing problems such as the creation of the optical guide and the precision of its installation, so it is difficult to say that it is a truly practical device.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical signal transmission device that has a simple configuration and transmits signals with a high S/N ratio, in order to eliminate the various drawbacks of conventional devices as described above.

First, the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram for explaining the principle of the present invention. In FIG. 1a, 1 is an optical fiber according to the present invention, 20 is the core of this optical fiber, and 2 is a low refractive index cladding covering the core. At both ends of the fiber, semiconductor light emitting elements (semiconductor lasers or light emitting diodes) 3 and 4 are arranged within a solid angle determined by the numerical aperture. Furthermore, both light-emitting elements are provided with reflective cavities 5 and 6, respectively, which provide mirror surfaces or completely scattering reflection. Therefore, the light from both light emitting elements introduced into the optical fiber is reflected infinitely, and optically performs a kind of integrating sphere function. When micro-windows 7 (the shape is a slit, circle, or ellipse, whichever suits the purpose is chosen) are opened at predetermined intervals as shown in the figure in the cladding of such an optical fiber, the intensity of light emitted from the window is , expressed in polar coordinates as shown by a solid line 8 and a dotted line 9. The former is light from element 3, and the latter is light from element 4.
corresponds to each light emitted from the 10 is a semiconductor light-receiving element (for example, a pin diode) having a condensing lens, for example, a fisheye lens 11. Therefore, if the optical fiber moves in the direction of the arrow, light emission from the light emitting element 3 causes the light receiving element 1 to move.
The light intensity received by the light emitting element 4 varies within the range shown by the solid line in FIG. Therefore, the light intensity received by the light receiving element 10 due to the light emission from both the light emitting elements 3 and 4, that is, the output electric signal of 10, is approximately as shown by the dashed line, and the comparison is made regardless of the movement of the optical fiber. It becomes a uniform value. Also, the size and interval of the side micro-windows 7 are selected in this way.

Next, FIG. 2 shows another configuration example of the present invention. This shows an example in which the semiconductor light emitting device 3 is arranged only at one end of the optical fiber 1, and in this case,
At the other end, a mirror surface or a perfect diffuse reflector 5 is directly placed. If the side micro-windows 7 are arranged at predetermined intervals from the left end to the right end, and the openings (micro-window diameters or slit widths) are gradually enlarged, the output electrical signal of the light-receiving element 10 will be
The value is approximately equal to the position of the fiber. Also, the window shape and dimensions and window spacing are selected accordingly.

FIG. 3 is a diagram showing the configuration of an embodiment of the optical device according to the present invention. In the figure, 12 is a rotating body, which rotates in the direction of the arrow in the figure. An optical fiber 1 is installed on the rotating body as shown in the figure. The light receiving element 10 placed on the stationary side 12' corresponds to the side micro-window 7 and is placed close to it so as to receive substantially the entire amount of light scattered from the micro-window 7. Reference numeral 13 denotes an electric signal source for commonly driving the light emitting elements 3 and 4, and this signal is subjected to pulse code modulation according to the physical quantity to be measured. Note that 16 is an amplifier.

Furthermore, the fiber 1 is arranged as shown in FIG.
They are arranged in a ring shape as shown by the arrows in the figure, with the points in contact with each other, and the ends are pulled out in a vertical direction to the bottom surface of the drum-shaped rotating body 12 and connected to the light emitting elements 3 and 4. In this way, the side micro-windows are arranged approximately on the same circumference.

In the above description, the case where the light emitting element and the light receiving element each have one channel has been described, but in the case where multiple channels are required, for example, there is a continuously rotating positron CT. (N. Nohara, IEEE, NS
−27 p1128/1136, 1980).

FIG. 5 shows an embodiment in which a multi-channel light emitting element is used, and FIG. 6 shows the arrangement relationship between the light emitting element and the light receiving element group in the case of multi-channel. Each optical fiber 1 has the required number of 5th fibers.
As shown in the figure, the signal sources 13, 13', . . . are arranged in a ring shape on the rotating body side, and signal sources 13, 13', . . . are independently coupled to each one (only two are shown in the figure). On the other hand, the stationary side light receiving elements 10, 10' are also arranged as multi-channels as shown in FIG. 6 so as to be optically coupled to the optical fiber group.

Here, the light receiving elements 10, 10' are connected to a switch means (semiconductor circuit) 14, and this switch means 14 corresponds to the rotation angle by output signal pulses from an angle encoder 15 coupled to the rotating body 12. can be switched. That is, while the optical fiber 1 is optically coupled to the element 10,
The switch 14 is connected to the element 10 side, and is connected to the 10' side when the fiber 1 begins to optically couple with the element 10'. 16 is an amplifier; 1
7 is a multiplexer, and each channel is sequentially switched in synchronization with rotation by the angle encoder 15 as well.

Therefore, no matter what position the fiber 1 is in, the output channels 18,1 of the multiplexer 17
8', . . . always provide output signals at terminals corresponding to the signal sources 13, 13', .

Next, FIGS. 7 and 8 show other embodiments of the present invention. If the amount of light from the small windows of the optical fiber is insufficient, connect the two fibers 1 and 1' as shown in Fig. 7, and shift the side small windows in the direction that they are adjacent to each other as shown in Fig. 7. If this is done, the light intensity distribution 8 expressed in polar coordinates will become as shown in FIG. 8, and a distribution suitable for the solid angle of convergence of the light receiving element 10 and sufficient intensity will be obtained. Thus, S/
Light with a good N ratio is exchanged.

As described above, in the present invention, the necessary number of side micro-windows are formed in the optical fiber at positions corresponding to predetermined intervals, so one or two micro-windows are formed.
A linear light source can be easily obtained using just one edge light source. Therefore, since the light emitting/light receiving elements can use minute single elements, high-speed response (M
Hz) signal transmission becomes possible. Moreover, since optical coupling can be performed positionally continuously, non-contact signal transmission such as S/N ratio can be realized.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams for explaining the principle of the present invention, FIGS. 3 and 4 are diagrams showing the configuration of an embodiment of the present invention, and FIGS. 5 and 6 are diagrams for explaining the principle of the present invention. FIG. 7 and FIG. 8 are diagrams showing still other embodiments of the present invention.

Claims (1)

[Claims] 1. An optical fiber installed in an annular shape on a rotating body and having a row of micro-windows formed in a cladding that is an outer covering part, and a semiconductor light emitting element attached to both ends or one end of the optical fiber. , an electric signal source for driving the light emitting element is provided on the rotating body side, and one or more semiconductors are arranged close to the row of micro-windows of the optical fiber and receive the modulated light from the rotating body side. An optical signal transmission device characterized in that a light receiving element is provided on a stationary side.