Moving object detecting photointerrupter and electronic device using the same

Abstract

A moving object detecting photointerrupter comprises one light emitting element for emitting light, at least two light receiving elements for receiving and detecting light emitted from the light emitting element and reflected off a moving object, and a detecting means for detecting movement of the moving object based on detection output from the light receiving elements when the light reflected off the moving object is received.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing an embodiment of a moving object detecting photointerrupter according to the present invention.

FIG. 2 is a cross-section showing the moving object detecting photointerrupter of FIG. 1.

FIG. 3 is a plane view showing approximate relative positions of a light emitting chip and a light receiving chip in the moving object detecting photointerrupter of FIG. 1.

FIG. 4 is a plane view showing the light receiving chip of the moving object detecting photointerrupter of FIG. 1.

FIG. 5 is a plane view showing the light emitting chip and the light receiving chip on lead frames in the moving object detecting photointerrupter of FIG. 1.

FIG. 6 is a graph showing changes in detection output of the light receiving elements of the light receiving chip when a moving object moves in front of the moving object detecting photointerrupter of FIG. 1.

FIG. 7 is a block diagram showing the light emitting element of the light emitting chip, the light receiving elements of the light receiving chip, and an arithmetic circuit in the moving object detecting photointerrupter of FIG. 1.

FIG. 8 is a timing chart showing a light emission drive signal and a light signal of the light emitting element, detection output of the arithmetic circuit, and so on in the moving object detecting photointerrupter of FIG. 1.

FIG. 9( a) and FIG. 9(b) are timing charts showing the light emission drive signal of the light emitting element, ambient light, the detection output of the arithmetic circuit, and so on in the moving object detecting photointerrupter of FIG. 1.

FIG. 10 is a plane view showing a conventional device in which two sensors have been arranged side by side.

FIG. 11 is a front view showing the device of FIG. 10.

FIG. 12 is a graph showing the detection output of each sensor in the device of FIG. 10.

Claims

1. A moving object detecting photointerrupter comprising one light emitting element for emitting light,at least two light receiving elements for receiving and detecting light emitted from the light emitting element and reflected off a moving object, anda detecting means for detecting movement of the moving object based on detection output from the light receiving elements when the light reflected off the moving object is received.

2. The moving object detecting photointerrupter according to claim 1, wherein the areas of light receiving regions of the light receiving elements are the same.

3. The moving object detecting photointerrupter according to claim 1, wherein an optical system is set for each of the light receiving elements in accordance with the area of the light receiving region of each of the light receiving elements.

4. The moving object detecting photointerrupter according to claim 1, wherein the light receiving elements have a plurality of light receiving regions.

5. The moving object detecting photointerrupter according to claim 1, wherein the detecting means obtains a difference in light reception start timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects movement of the moving object when the difference in the light reception start timings is equal to or greater than a prescribed value.

6. The moving object detecting photointerrupter according to claim 1, wherein the detecting means obtains a difference in light reception start timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects movement of the moving object when the difference in the light reception start timings falls within a prescribed range.

7. The moving object detecting photointerrupter according to claim 5 or claim 6, wherein the detecting means detects the movement of the moving object based on the detection output of the light receiving elements regardless of the sequence of the light reception start timings of the light receiving elements receiving light reflected off the moving object.

8. The moving object detecting photointerrupter according to claim 5 or claim 6, wherein the detecting means obtains the sequence of the light reception start timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects the direction of movement of the moving object based on the sequence.

9. The moving object detecting photointerrupter according to claim 5 or claim 6, wherein the detecting means obtains the sequence of the light reception start timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects movement of the moving object only when the sequence matches a prescribed sequence.

10. The moving object detecting photointerrupter according to claim 1, wherein the detecting means obtains a difference in light reception end timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects movement of the moving object when the difference in the light reception end timings is equal to or greater than a prescribed value.

11. The moving object detecting photointerrupter according to claim 1, wherein the detecting means obtains a difference in light reception end timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects movement of the moving object when the difference in the light reception end timings falls within a prescribed range.

12. The moving object detecting photointerrupter according to claim 10 or claim 11, wherein the detecting means detects the movement of the moving object based on the detection output of the light receiving elements regardless of the sequence of the light reception end timings of the light receiving elements receiving light reflected off the moving object.

13. The moving object detecting photointerrupter according to claim 10 or claim 11, wherein the detecting means obtains the sequence of the light reception end timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects the direction of movement of the moving object based on the sequence.

14. The moving object detecting photointerrupter according to claim 10 or claim 11, wherein the detecting means obtains the sequence of the light reception end timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects movement of the moving object only when the sequence matches a prescribed sequence.

15. The moving object detecting photointerrupter according to claim 1, wherein the detecting means obtains light reception start timings of the light receiving elements and light reception end timings of the light receiving elements receiving light reflected off the moving object based on the detection output of the light receiving elements, and detects movement of the moving object based on the light reception start timings and the light reception end timings.

16. The moving object detecting photointerrupter according to claim 1, wherein the detecting means detects the movement of the moving object based on the detection output of the light receiving elements when light emitting timing of the light emitting element and light reception timings of the light receiving elements match continuously a plurality of times.

17. The moving object detecting photointerrupter according to claim 16, wherein the detecting means maintains a detection state if a high-frequency light that does not match the light reception timing enters when the light emitting timing of the light emitting element and the light reception timings of the light receiving elements match.

18. The moving object detecting photointerrupter according to claim 16, wherein the detecting means does not detect the movement of the moving object if a high-frequency light that does not match the light reception timing enters when the light emitting timing of the light emitting element and the light reception timings of the light receiving elements match.

19. The moving object detecting photointerrupter according to claim 1, wherein a collimating lens is provided to the light-emitting side of the light emitting element or the light-incident side of the light receiving elements.

20. An electronic device, wherein the moving object detecting photointerrupter according to claim 1 is used.