JPS5829019B2 - Optical relay method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical relay system for mobile objects.

FIG. 1 is a configuration diagram for explaining a typical optical relay system.

In FIG. 1, an output signal from a TV camera 1 is input to a light transmitter 2, and passes through an amplifier circuit 2a and a modulation circuit 2b to a drive circuit 2.
The light emitting diode 2d is driven by the light emitting diode 2d, and the light is projected into space by the lens 2e, and reaches the light receiver 3.

The light receiver 3 is arranged optically opposite to the light transmitter 2, and the incident light is focused on a photodetector 3d by a lens 3e, and the output signal of the photodetector 3d is sent to a preamplifier circuit 3.
c, the demodulation circuit 3b, the amplifier circuit 3a, the signal is outputted, and received by the video monitor 4.

FIG. 2 is a diagram showing a concept of an application form of the optical relay method shown in FIG. Vehicle 5 coming
Emits light towards.

A light receiver 3 is mounted on the vehicle 5 facing in the direction of movement of the vehicle, and incident light from the light transmitter 2 modulated by the output signal of the TV camera 1 is transmitted to the video monitor 4 via the light receiver 3. Received.

In this case, the light projection angle 2f of the light transmitter 2 is set to an angle that satisfies the incident light intensity required by the light receiver 3 when the distance between the light transmitter 2 and the light receiver 3 is maximum. If the light receiver 3 does not deviate from the light projection angle 2f, the intensity of light incident on the light receiver 3 increases as the vehicle 5 approaches the light transmitter 2, so automatic gain control is performed in the amplifier circuit 3a of the light receiver 3. There is a limit to saturation of the photodetector 3d, etc.

Furthermore, if the light transmission direction of the light transmitter 2 is fixed, when the vehicle 5 approaches the light transmitter 2, the light receiver 3 will often deviate from the light projection angle 2f. If necessary, as shown in Figure 3, the output signal of the camera 1 is divided into multiple video signal systems by the video signal splitter 6, and a light transmitter 2.2', 2'' is connected to each system. It is necessary to expand the relay range.

The present invention solves the above-mentioned drawbacks of the optical relay system and provides an optical relay system that enables relaying over a wide range with one light transmitter.

FIG. 4 shows an embodiment of the present invention, in which an output signal from a TV camera 1 is input to a light transmitter 2, and a distance measuring device 7 is input to the light transmitter 2.
Distance information up to the vehicle 5 is supplied from the vehicle 5, and the projection angle of the light transmitter 2 is controlled using the distance information as a variable.

That is, compared to the projection angle 2f when the vehicle 5 is at the position shown in the figure, when the vehicle 5 is at a position 5' above the distance, it becomes an angle 2f' which is twice 2f, and when the vehicle 5 is at a position 5'' above the distance Sometimes 2F
The projection angle is controlled to be 2f'' which is four times the angle of .

When the distance between the light transmitter 2 and the light receiver 3 is constant, the intensity of the incident light on the light receiver 3 is inversely proportional to the light projection angle of the light transmitter 2, so the relationship between the distance and the light projection angle is expressed as above. Once set, receiver 3
The intensity of the incident light remains at a constant level regardless of the distance.

Therefore, the amplifier 3a of the light receiver 3 does not require extensive automatic gain control, and there is no fear that the photodetector 3d etc. will be saturated at short distances.

Furthermore, as is clear from FIG. 4, the increase in the light projection angle due to the proximity of the vehicle 5 acts to prevent the light receiver 3 from deviating from the light projection angle 2f. It can cover a wide relay range.

FIG. 5 shows an embodiment of the projection angle control mechanism, in which the light emitting diode 2d is held by an adjustment mechanism 8 so as to move back and forth on the optical axis of the lens 2e.
In contrast to the projection angle 2f when the beam is near the focal point of the lens 2e, the projection angle becomes 2r'' at a position 2d'''' moved toward the lens.

The adjustment mechanism 8 is driven by a servo motor 9 and a servo amplifier 10.

The output signals of the position detection potentiometer 2 mechanically combined with the adjustment mechanism 8 and the distance measuring device 7 are input to the comparison/discrimination circuit 11, and a signal such that the difference between the two signals becomes O is sent to the servo amplifier 10. control is performed so that the distance between the light transmitter and light receiver and the light projection surface are inversely proportional to each other.

FIG. 6 shows an embodiment in which the light emitting diode 2d is moved away from the optical axis of the lens 2e to a position 2d'' on the lens 2e side, and the projection angle 2f'' is such that it spreads to one side as shown in the figure. This corresponds to the embodiment shown in FIG.

In this embodiment, a method in which the distance measuring device 7 is provided has been described, but if the speed change of the vehicle 5 is a constant pattern, the speed change up to the vehicle 5 programmed according to the control pattern based on information from the distance measuring device 7 is It is also possible to replace the method with a method of controlling the projection angle 2f in time series based on the distance information.

Further, in this embodiment, an example in which the light transmitter is fixed and the light receiver is moved has been described, but the present invention can be similarly applied to a case where the light transmitter is moved.

As explained above, according to the present invention, a wide relay range can be covered with one light transmitter.

[Brief explanation of drawings]

Figure 1 is a configuration diagram for explaining a typical optical relay system.
Figure 2 is a conceptual diagram of one application form of the optical relay system in Figure 1, Figure 3 is a conceptual diagram of the optical relay system in Figure 1 applied to a wide range of relays using conventional technology, and Figure 4 is a conceptual diagram of the application of the optical relay system in Figure 1. A conceptual diagram for explaining an embodiment of the invention, and FIGS. 5 and 6 are configuration diagrams for explaining a projection angle control mechanism in an embodiment of the invention. 1...TV camera, 2...Light transmitter, 2
d, 2d'. 2d''...Light emitting diode, 2e...
・Lens, 2f, 2f', 2f'', 2f
″′...=...Emission angle, 3...Receiver, 7...
...Distance measuring device, 8...Adjustment mechanism.

Claims (1)

[Claims] 1. In a method in which light modulated by an electrical signal is emitted by a light transmitter through a lens provided on the light transmitter, the light is received by a light receiver, and then demodulated to obtain the original electrical signal. means for measuring the distance between the light source and the light receiver and generating an output signal corresponding to the distance; and means for controlling the projection angle of the light transmitter so as to be inversely proportional to the distance using the output signal. An optical relay system characterized by the following.