Patent ID: 8823684
Filing Date: 2014-09-02
Classification: G06F

Abstract:
1. A position detection system that uses a shadow of an object to detect a position of the object, comprising: a light source group including light sources that emit light onto said object; a light receiving sensor in which light receiving elements that measure a light intensity distribution of said light, which has been changed by a shadow generated by said object, are arranged; and a phosphor that fluoresces in response to invisible light, which is said light arranged on an optical path of said light of said light source to said light receiving element, wherein said phosphor emits by fluorescence, in response to the invisible light received, light of a second wavelength that is different from light of a first wavelength at which a photoelectric conversion body included in said light receiving element generates a largest reverse bias current upon light reception, and wherein said photoelectric conversion body satisfies condition formulas A to C below: where, Cs1: a reverse bias current that the photoelectric conversion body initially generates upon receipt of light of the first wavelength Ce1: a reverse bias current that the photoelectric conversion body generates after having received the light of the first wavelength for a prescribed period of time RCR1: a characteristic change rate of the photoelectric conversion body calculated using Cs1 and Ce1 when the photoelectric conversion body receives light of the first wavelength Cs2: a reverse bias current that the photoelectric conversion body initially generates upon receipt of light of the second wavelength Ce2: a reverse bias current that the photoelectric conversion body generates after having received the light of the second wavelength for a prescribed period of time RCR2: a characteristic change rate of the photoelectric conversion body calculated using Cs2 and Ce2 when the photoelectric conversion body receives light of the second wavelength.