Optical position detecting device and recording medium
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Abstract
The position of a light blocking object is detected not only within a display screen, but also outside the display screen. With the use of the function of detecting the position in a region outside the display screen, it becomes possible to provide virtual buttons in this region and detect dust around a light retro-reflector. Dirt on the light retro-reflector is detected based on the levels of light receiving signals of optical units.
24 Citations
6 Claims
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1-4. -4. (canceled)
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5. An optical position detecting device comprising:
- a light retro-reflector provided outside a predetermined region;
at least two optical transceivers, each including an optical scanning unit for angularly scanning light in a plane substantially parallel to the predetermined region and a light receiving unit for receiving reflected light from a portion of said light retro-reflector irradiated with the scanning light;
a detector for detecting a position of a light blocking object present in a region optically scanned by said optical scanning units, based on scanning angles of said optical scanning units and results of receiving light by said light receiving units; and
a cover for covering said optical transceivers, said optical position detecting device being characterized by further comprising;
a measuring unit for measuring a base potential of a light receiving signal in said light receiving unit;
a comparing unit for comparing the measured base potential with a predetermined potential; and
a judging unit for making a judgment that said cover is dirty when the measured base potential is higher than the predetermined potential.
- a light retro-reflector provided outside a predetermined region;
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6-9. -9. (canceled)
Specification