JPS61195310A - Photoelectric converting device - Google Patents

Abstract

PURPOSE:To place the photo-couplers adjacent to one another to minimize device size by providing a selective circuit for selective activation of adjacent photo-couplers with a relative shift in timing. CONSTITUTION:The photo-couplers mounted on a rotating member 1 on which 4-bit codes are formed are sequentially and time-sharingly selected by the selecting circuit 6. The coupler 2 is first selected, a light emitting element 2a is lighted, a gate circuit 12 is opened and the output of a light receiving element 2b is produced through an inverter 8 at the gate circuit 12. Since the other gate circuits 13-15 are closed, the output is not produced even when one of the elements 3b-5b is sensitized by the detour of light from the light emitting element 2a. Since the neighboring photo-couplers are selectively activated with a relative shift in timing, the system is not affected by light detour from the other elements so that the size may be reduced while the electric source may be of a limited capacity because of split type activation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoelectric conversion device such as a rotary encoder.

[Prior art] For example, in a rotary encoder using a photocoupler, a through hole representing a 4-bit code is formed in a disc, and four sets of photocouplers are arranged in parallel across the disc to encode the code. reading.

[Problems to be solved by the invention] In the above, since light wraps around from the through hole,
The interval between each bit could not be reduced much, making it difficult to miniaturize. Moreover, the photocoupler's light-emitting element and light-receiving element are required to have strong directivity, and optical axis alignment is also required to be highly accurate.

The present invention aims at downsizing by allowing photocouplers to be arranged adjacently or in contact with each other.

[Means for Solving the Problems] According to the present invention, at least adjacent photocouplers are operated with timings shifted from each other.

[Embodiment] In the drawings, reference numeral 1 denotes a rotating body constituting a moving body, which has a 4-bit code formed by slits 1a, 1a, and rotates about an axis 1b. 2 to 5 are light emitting elements 2a to 5a and light receiving elements 2b to 5b, respectively.
It is a photocoupler consisting of 6 is a selection circuit that sequentially selects the photocouplers 2 to each other in a time-sharing manner; 7 is a timing pulse generator that generates a timing pulse for selection of the selection circuit 6; 8 to 11 are inverters, and 12 to 15 are gate circuits.

In the above configuration, when the photocoupler 2 is first selected by the selection circuit 6 and the light emitting element 2a is turned on, the gate circuit 12 is simultaneously opened. Therefore, the light receiving element 2 at this time
An output of b is generated from the gate circuit 12 via the inverter 8. Now, since the other gate circuits 13, 14, and 15 are closed, the photocouplers are close to each other, and the light emitting element 2
Even if any of the light-receiving elements 3b to 5b is sensitive to the wraparound of light from a, no output is generated from them.

Next, when the photocoupler 3 is selected and its light emitting element 3a lights up, the gate circuit 13 is opened and the output of the light receiving element 3b at this time is generated.

Similarly, the output of the photocoupler 4.5 is generated sequentially from the gate circuit 14.15.

In this way, by operating each photocoupler sequentially in a time-sharing manner, erroneous data will not be generated even if light from other photocouplers wraps around, and each photocoupler can be placed close to each other or in parallel. can be set up.

In the above embodiment, each photocoupler was operated one by one, but in general, the only problem is the wraparound of light from adjacent photocouplers, so adjacent photocouplers are operated at different timings. That's fine. For example, the photocouplers 2 and 4 are operated simultaneously, and at the next timing, the photocouplers 2 and 4 are operated simultaneously. According to this, since only two systems of timing pulses are required, the data reading speed becomes faster, and even if the rotational speed of the rotating body 1 is high, the data can be read accurately.

The present invention provides rotary encoders, card readers, etc.
It can be applied to any photoelectric conversion device that optically reads information.

[Effects] According to the present invention, since at least adjacent photocouplers are selectively operated by shifting the timing, each photocoupler is not affected by the wraparound of light from other photocouplers, and each photocoupler can be operated in close proximity. They can be arranged side by side or in contact with each other, allowing for miniaturization. In addition, since each photocoupler is operated separately, a small-capacity power supply is required.

[Brief explanation of drawings]

The drawing is an electrical circuit diagram showing an embodiment of the present invention. 1... moving object, 2~5L...photo coupler, 2a to 5a... light emitting element, 2b to 5b...light receiving element, 6...Selection circuit that's all

Claims (1)

[Claims] A photoelectric conversion system in which a plurality of photocouplers each consisting of a light-emitting element and a light-receiving element are arranged in parallel, and a moving body on which desired information is formed by a light passage control section is moved between the light-emitting element and the light-receiving element of each of the photocouplers to read the information. In the device,
A photoelectric conversion device comprising a selection circuit that selectively operates at least adjacent photocouplers at different timings.