Patent ID: 8749524
Filing Date: 2014-06-10
Classification: G01B,G01C,G06F

Abstract:
1. An apparatus with a position detection function which detects a position of a target object, the apparatus comprising: a translucent portion; a plurality of detection light sources that emit detection light toward the translucent portion, the plurality of detection light sources having a plurality of first light-emitting elements and a plurality of second light-emitting elements; a light detector that receives reflected light that is created by the target object when the target object reflects the detection light; a light source driver that selectively turns on the plurality of first and second light-emitting elements; and a position detector that detects the position of the target object based on the received reflected light by the light detector, wherein in a plan view, the plurality of first light-emitting elements are located on a first circumference with a first diameter so as to around the light detector, the plurality of second light-emitting elements are located on a second circumference with a second diameter that is shorter than the first diameter so as to around the light detector, and the first and second circumference have a same center, the plurality of first light-emitting elements and the plurality of second light-emitting elements alternately emit the detection light with same intensity, the position detector detects that the target object is located closer to the first circumference than the second circumference when first intensity of the reflected light emitted by the plurality of first light-emitting elements is larger than second intensity of the reflected light emitted by the plurality of second light-emitting elements, and the position detector detects that the target object is located closer to the second circumference than the first circumference when the first intensity of the reflected light emitted by the plurality of first light-emitting elements is smaller than the second intensity of the reflected light emitted by the plurality of second light-emitting elements.