JPH04156717A - Mutual interference preventing device for photosensor - Google Patents

Abstract

PURPOSE:To prevent the mutual interference of each photosensor by providing a means to let plural light emitting parts emit light successively by dividing time without letting them emit the light at a time. CONSTITUTION:A synchronizing pulse generating part 1 generates a synchronizing pulse for flickering the light of a light emission diode in a light emitting part 2, and the light emitting part 2 makes the light emission diode light by the signal of this synchronizing pulse. A light receiving part 3 converts the signal of the light from the light emitting part 2 into an electric signal, and a pulse signal separating part 4 compares the received electric signals by using the synchronizing pulse signal, and separates only a necessary signal. Sensor output 5 is the separated signal. By flickering respective photosensors as synchronizing them and staggering timing in this way, the mutual interference of each sensor can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for preventing mutual interference of photosensors, and more particularly to a device for preventing mutual interference between a large number of photosensors mounted in close proximity to each other.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional photosensor.

In FIG. 3, a plurality of light emitting sections 14 include light emitting elements, and are modulated by a sense amplifier section. A light receiving section 15 is installed corresponding to the light emitting section 14, each having a photo sensor, and the sensor output is sent to the sensor amplifier section 16.
is applied to

The conventional photosensor 4 of this type modulates the light from the light emitting section 14 to a specific frequency, and then transmits the light to the receiving section 15.
After receiving the signal, it is divided by a filter that allows only specific frequencies to pass through, thereby preventing interference with external light such as natural light.

[Problem to be solved by the invention]

In the conventional lighting device described above, when the distance between the photosensors is close, each photosensor emits light asynchronously, so even though interference from natural light can be prevented, interference from neighboring photosensors may cause light to emit light. The drawback is that when light enters, it interferes with each other.

SUMMARY OF THE INVENTION An object of the present invention is to provide a mutual interference prevention device for photosensors that solves the above-mentioned drawbacks and prevents interference from adjacent photosensors.

[Means to solve the problem]

The configuration of the mutual interference prevention device for photosensors of the present invention is such that a plurality of light emitting sections are provided, and a light receiving section consisting of a photosensor is provided corresponding to each of the light emitting sections, so that the plurality of light emitting sections do not emit light at the same time. It is characterized in that it is provided with means for dividing the light and emitting light one after another.

〔Example〕

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

FIG. 1 is a block diagram showing a mutual interference prevention device for photosensors according to an embodiment of the present invention.

In FIG. 1, in this embodiment, a synchronization pulse generating section 1 generates a synchronization pulse for blinking the light of a light emitting diode in a light emitting section 2. As shown in FIG. In the light emitting section 2, the light emitting diode is turned on by the signal of this synchronization pulse. The light receiving section 3 converts the light signal from the light emitting section 2 into an electrical signal. The pulse signal separation section 4 compares the received electrical signals using a synchronous pulse signal and separates only necessary signals. Sensor output 5 is a separate signal.

FIG. 2 is a timing diagram of FIG. 1, and the horizontal axis is the time axis. Waveforms 6, 8, and 1 are applied to the light emitting diodes of light emitting unit 2, respectively.
The lights are turned on one after another while shifting the time at a timing such as 0.12. The light receiving unit 3 should be able to receive signals at the same timing if the light is passing through, so the determination is made at the timings of arrows 7°, 9, 11, and 13, respectively, while the lights are on.

Since a large number of light emitting units 2 are not lit at the same time, there is no fear of mutual interference.

Furthermore, if the signal separation unit 4 receives sensor input only during this lighting period, it will not receive any natural light or the like outside of that period.

〔Effect of the invention〕

As described above, the present invention has the effect of preventing mutual interference between the respective sensors by synchronizing the adjacent photosensors and causing them to blink at different times.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a mutual interference prevention device for photosensors according to an embodiment of the present invention, FIG. 2 is a timing diagram of the embodiment of FIG. 1, and FIG. 3 is a block diagram of a conventional photosensor. 1... Synchronous pulse generating section, 2.14... Light emitting section, 3
．． 15... Light receiving section, 4... Signal separating section, 5... Sensor output, 6.8.10, 12... Waveform indicating that the light emitting section is lit, 7, 9, 11.13... - Arrow indicating the time of judgment of the light receiving section, 16...Sensor amplifier section.

Claims (1)

[Claims] A plurality of light emitting sections are provided, a light receiving section consisting of a photosensor is provided corresponding to each of the light emitting sections, and a means is provided for causing the plurality of light emitting sections to emit light one after another in a time-sharing manner instead of causing the plurality of light emitting sections to emit light simultaneously. A featured photo sensor mutual interference prevention device.