JPH0576141U - Wireless two-way optical communication device - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the light emission signal from being directly received by the light receiving part due to the light wraparound phenomenon. This wireless two-way optical communication device sends a control signal, which is an intermittent signal of light, from a control unit (11) of a remote control device to a control device via a light emitting unit, and transmits the light from the control device. A response signal composed of an intermittent signal is received by the light receiving unit of the control unit (11) through the light receiving unit, a part of the control signal sent from the control unit (11) is received, and the duty of the control signal is changed. It is provided with a sneak inhibition circuit (21) for canceling a signal received by the light receiving unit due to a sneak phenomenon.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a wireless bidirectional optical communication device.

[0002]

[Prior Art]

 Optical communication does not cause problems such as impedance matching, parasitic capacitance, and restrictions on installation location, which are problems in wired communication.Therefore, it is necessary to control air conditioners for coolers, household appliances such as channel controls for TVs and video equipment, or It has also come to be used as a device for investigating the current state of equipment inside a device such as a vending machine installed in various places without the operator directly opening and closing the device.

[0003]

[Problems to be solved by the device]

 In such optical communication, bidirectional communication is often performed, and in such a bidirectional optical communication data transmission system, the light emitted from the light emitting unit of the remote control device is received by the light receiving unit of the control device itself. There was a case in which a direct reception, a so-called wraparound phenomenon, occurred and a malfunction occurred.

FIG. 3 shows an example of a light transmitting / receiving section of a remote control device used in a conventional bidirectional optical communication data transmission system. In FIG. 3, a control signal CS sent from a control section (CPU) 11 is shown. Is taken into the modulator 12 of the light emitting unit according to the clock CK, and after being modulated here, the output transistor 13 arranged on the output side is turned on / off to make the light emitting diode 14 blink, and the control device To the optical control signal LCS. In this case, a part of the light control signal LCS sent from the light emitting diode 14 is diffusely reflected and is received by the light receiving diode 15 which constitutes the light receiving portion due to the above-mentioned wraparound phenomenon, and is received by the control portion 11 via the amplifier 16. It is sent and the control unit 11 operates as if it received a signal from a control device. In particular, this becomes a problem when the device is miniaturized and the light emitting diode 14 and the light receiving diode 15 are located close to each other.

[0005]

[Means for Solving the Problems]

 In order to solve such a problem, in the present invention, the control unit of the remote control device sends a control signal composed of an intermittent signal of light to the control device via the light emitting unit, and the intermittent control of light from the control device is performed. In a wireless two-way optical communication device in which a response signal composed of a signal is received by the light receiving unit of the control unit via the light receiving unit, a part of the control signal sent from the control unit is received, A wireless bidirectional optical communication device is provided, which is provided with a sneak-in prohibition circuit that changes the duty of a control signal and cancels the signal received by the light receiving unit by a sneak-through phenomenon.

[0006]

[Action]

 With this configuration, the control unit does not receive an erroneous signal due to the light wraparound phenomenon that occurs when the control unit wirelessly sends the optical control signal to the control device, and the erroneous operation of the control unit can be prevented. .

[0007]

【Example】

 FIG. 1 shows an embodiment of a bidirectional optical communication device according to the present invention, and particularly shows a portion of a light emitting and receiving portion of a remote control device corresponding to FIG. Therefore, the reference numerals used in FIG. 1 are the same as those in FIG. 3, and the same reference numerals are used.

In FIG. 1, a sneak prevention circuit 21 characterized by the present invention is arranged between the light emitting portion and the light receiving portion. The sneak-in prohibition circuit 21 includes an integration circuit composed of resistors 21a and 21b, a diode 21c, and a capacitor 21d, a hysteresis circuit composed of amplifiers 21e and 21f, and a logic negation circuit (inverter) 21g. , AND gate 21h.

In such a configuration, for example, when a rectangular pulse having a duty ratio of 50% shown in FIG. 2A is transmitted from the control unit 11, this is transmitted via the modulator 12 and the transistor 13. It is sent to the light emitting diode 14 and is sent to the control device 50 as an intermittent signal of light. The rectangular pulse shown in FIG. 2A sent from the control unit 11 is also sent to the sneak-in prohibition circuit 21, and is an integrating circuit configured by resistors 21a and 21b, a diode 21c, and a capacitor 21d. The waveform can be changed to that shown in FIG.

The output of the integrating circuit shown in FIG. 2B is changed to the waveform shown in FIG. 2C due to the hysteresis characteristic of the amplifiers 21e and 21f. This output is sent to the logical sum circuit 21h. The output from the logical NOT circuit 21g is also supplied to the logical sum circuit 21h.

By the way, a part of the intermittent signal of the light transmitted from the light emitting diode 14 of the light emitting portion is received by the light receiving diode 15 of the light receiving portion due to the so-called wraparound phenomenon, and is transmitted to the amplifier 22, where it is processed. The time is delayed by the time d (see FIG. 2D), inverted by the logical NOT circuit 21g (see FIG. 2E), and the inverted signal is sent to the logical OR circuit 21h. The logical sum circuit 21h calculates the logical product of the waveforms shown in (c) and (e) of FIG. 2 and sends it to the control unit 11 as an output. In this case, the sneak signal shown in FIG. 2 (e) is output from the hysteresis circuit by changing the duty ratio of the TTL level by the integrator circuit and the hysteresis circuit of the sneak prevention circuit 21 and the waveform of FIG. 2 (c). Since the control unit 11 is adjusted so as to cancel the above, the control unit 11 is controlled when the data is transmitted from the control unit 11, that is, when the control unit 11 sends the signal shown in FIG. In this case, it is possible to prevent the reception signal from being supplied as shown in FIG.

[0012]

[Effect of the device]

 As described above, according to the wireless two-way optical communication device of the present invention, the control unit receives the signal due to the light wraparound phenomenon that occurs when the control unit wirelessly sends the optical control signal to the control device. And the malfunction of the control unit can be prevented. As a result, the light emitting diode and the light receiving diode can be brought close to each other, and the device can be downsized. Further, as in the present embodiment, a simple circuit configuration is provided by canceling the signal generated by changing the duty ratio of the TTL level by using the integrating circuit and the hysteresis circuit in the sneak-in prohibition circuit and the signal by the sneak. It is possible to solve the problems described above and obtain a bidirectional optical communication device that is strong against external light other than data and electrical noise. Further, according to the present invention, it is not necessary to distinguish the time of data transmission from the time of data reception by software, and the load on software can be lightened.

[0013]

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a wireless bidirectional optical communication device according to the present invention, and particularly showing a part of a light transmitting / receiving part of a remote control device.

FIG. 2 is a waveform diagram showing a waveform of each part of FIG.

FIG. 3 is a system diagram showing an embodiment of a conventional wireless bidirectional optical communication device.

[Explanation of symbols]

 11 Control part 12 Modulator 13 Transistor 14 Light emitting diode 15 Light receiving diode 16, 21e, 21f, Amplifier 21h OR circuit 21a, 21b Resistor 21c Diode 21d Capacitor 21g Logical NOT circuit

Claims (1)

[Scope of utility model registration request] 1. A control signal of an intermittent light signal is sent from a control unit of a remote control device to a control device via a light emitting unit, and a response signal consisting of an intermittent light signal from the control device is sent via a light receiving unit. In a wireless bidirectional optical communication device adapted to be received by a light receiving unit of the control unit, a part of a control signal transmitted from the control unit is received, and the duty of the control signal is changed to cause the light receiving unit by a wraparound phenomenon. A wireless bidirectional optical communication device comprising a sneak-in prevention circuit for canceling a signal received at.