JPH0519980U - Target object movement detection device - Google Patents

Abstract

(57) [Summary] [Purpose] It can be used to notify the driver that the preceding vehicle has started, such as when the vehicle has stopped after being stopped due to traffic congestion, etc.
The overall purpose is relatively simple construction. [Structure] Light control circuit 2 activated by operating switch 1
The drive continuation signal b and the amplification command signal c are input to the light emitting element drive circuit 3, the drive current d is supplied to the light emitting element 4 when the drive continuation signal b is turned on, and light is emitted during the on period of the amplification command signal c. When the drive current d to the element 4 is gradually increased and its light emission is gradually increased and the light receiving signal e from the light receiving element 5 reaches a preset value, an amplification command signal from the light control circuit 2 c is turned off, and when the received light signal e decreases or disappears, a notification is given.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a movement detecting device for a target object. For example, when your own car approaches and stops after a car (front car) that is stopped due to traffic jam, the front car will start without realizing it, and you will be rushed to notice yourself from the car behind you. May start the car. The present invention is designed to notify the driver that the preceding vehicle has started in such a case.

[0002]

[Prior Art]

 Conventionally, a device using ultrasonic waves has been used as a notification means in such a case. This is to emit an ultrasonic pulse forward at regular time intervals, receive the ultrasonic pulse reflected from the target object, that is, the vehicle in front, and compare the time interval of this received pulse with the time interval of the emission pulse. When this is different, it is notified that the preceding vehicle has gone away.

[0003]

[Problems to be solved by the device]

 A conventional device using ultrasonic waves requires a complicated circuit configuration such as a storage unit that stores the time interval of the emitted ultrasonic pulse and a comparison unit that compares the time interval of the emitted pulse with the time interval of the received pulse. There was a problem. The present invention proposes a movement detection device for a target object that avoids these problems and achieves the object with a simple circuit configuration.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in the present invention, an optical control circuit 2 is provided, which is activated by a trigger signal a based on the operation of the switch 1 to output a drive continuation signal b and an amplification command signal c, The light emitting element drive circuit 3 is provided to supply the drive current d to the light emitting element 4 by inputting the drive continuation signal b 1, and gradually increase the drive current d to the light emitting element 4 by inputting the amplification command signal c. When the light receiving signal e from the light receiving element 5 reaches a preset value by turning the amplification command signal c off from the light control circuit 2 off and the light receiving signal e decreases , The notification information is output.

[0005]

【Example】

 An example of a movement detecting device for a target object according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of this device, and FIG. 2 is an explanatory diagram of its operation. By operating the switch 1 shown in FIG. 1, a trigger signal a (FIG. 2a) is generated, which is input to the light control circuit 2 to be activated. By this activation, a drive continuation signal b (FIG. 2b) and an amplification command signal c (FIG. 2c) are obtained from the light control circuit 2, and both signals b and c are input to the light emitting element drive circuit 3 of the next stage. .

The light emitting element drive circuit 3 controls the light emission of the light emitting element 4. The light emitting element 4 is made to emit light while the drive continuation signal b is being input (hereinafter, referred to as an on period), and the drive continuation signal b is turned off. The driving state of the light emitting element drive circuit 3 is controlled so as to stop the light emission. Further, during the ON period of the amplification command signal c, the output d (FIG. 2d) from the light emitting element drive circuit 3 to the light emitting element 4 is gradually increased, that is, the light emission amount of the light emitting element 4 is gradually increased (the light emission is gradually When the amplification command signal c is turned off, the drive control is performed so that the amount of light emitted from the light emitting element 4 becomes constant thereafter.

The light from the light emitting element 4 is reflected by the front target body 7, is received by the light receiving element 5, is converted into a light receiving signal e (FIG. 2 e), and is input to the light receiving detection circuit 6. The magnitude of the received light signal e is determined in relation to the intensity of the emitted light and the reflection condition from the target body 7, and gradually increases as the light emission amount of the light emitting element 4 gradually increases. In this case, the light emitted from the light emitting element 4 may be modulated and demodulated by the light reception detection circuit 6 so that only the light from the light emitting element 4 of its own can be selected. For easy understanding, the output d and the received light signal e are shown as sinusoidal waveforms in FIG.

When the light reception signal e reaches a certain value (preset threshold value), the light reception detection circuit 6 outputs a detection signal f (FIG. 2f), that is, the detection signal f is turned on, and this is sent to the light control circuit 2. The amplification command signal c is input and turned off. As a result, the amount of light emitted from the light emitting element 4 becomes constant. This light emission is continued as long as the drive continuation signal b from the light control circuit 2 is on.

In this state, when the target body 7 moves away or the target body 7 disappears, the amount of light received by the light receiving element 5 decreases, so the detection signal f from the light receiving detection circuit 6 is turned off. Therefore, the movement of the target 7 can be detected by detecting the change of the detection signal f from ON to OFF. The means for detecting the change of the detection signal f from ON to OFF can be constituted by a conventionally known technique, and since it is not particularly related to the gist of the present invention, its detailed description will be omitted.

Therefore, by installing this device in a vehicle, if the switch 1 is pushed when the vehicle comes close to the front vehicle and is stopped, the operation of this device is started, and the light receiving element 5 is activated when the front vehicle moves away. Since the amount of light received by the light receiving device decreases, this is detected by the detection signal f from the light receiving detection circuit 6. This notifies that the preceding vehicle has started. In the above description, the case where this device is used in a vehicle has been described, but the device according to the present invention can also be used when detecting the movement of another target object.

[0011]

[Effect of the device]

 According to the movement detecting apparatus of the target object according to the present invention, the object can be achieved by a circuit configuration that only detects the intensity of received light and controls the intensity of light emission, and can be configured relatively easily as a whole. effective.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of a movement detecting device of a target body according to the present invention.

FIG. 2 is a waveform diagram used to describe the operation of FIG.

Claims (1)

[Scope of utility model registration request] 1. A light control circuit which is activated by operating a switch and outputs a drive continuation signal and an amplification command signal, and a drive current is supplied to a light emitting element by the input of the drive continuation signal, and an amplification command signal is input by the amplification command signal. The light-receiving element drive circuit that gradually increases the drive current to the light-emitting element to gradually increase the light emission, and the light-receiving signal from the light-receiving element that receives the light emitted from the light-emitting element and reflected by the target body are input. And a light-reception detection circuit that turns off the amplification command signal from the light control circuit when the light-reception signal reaches a preset value.