Patent ID: 6353217
Filing Date: 2002-03-05
Classification: G06F

Abstract:
A transmitter receiver comprising:a transmitter including pairs of light-emitting portions having directivity, the light-emitting portions being arranged such that the light-emitting central axes of each pair of light-emitting portions are inclined in the directions opposite to each other in the case where the light-emitting central axis is the direction in which the intensity of light emitted by the light-emitting portion is the strongest; a receiver including a light-receiving portion that receives light emitted by the pairs of light-emitting portions; and a detecting section that compares the intensities of light received by the receiver and detects a change in the relative angle between the receiver and the transmitter, wherein a mask is provided for masking the inclined side portions of the pairs of light-emitting portions that face the light-receiving portion because the light-emitting central axes are inclined.