Patent ID: 7755743

Claim:
A spatial information detection apparatus comprising: a light-emitting element ( 100 ) configured to emit an intensity-modulated light to a target space; a lighting signal generation circuit ( 10 ) configured to generate a lighting timing signal (E 1 ) which determines a lighting timing of said light-emitting element, a light-emitting element driving circuit ( 30 ) configured to output a light-emitting element driving signal (E 2 ) in response to said lighting timing signal for generation of said intensity-modulated light from said light-emitting element; a light-receiving element ( 200 ) configured to receive said intensity-modulated light reflected from an object in said target space; an information output circuit ( 300 ) configured to extract a light intensity of the light received at the said light-receiving element for each of a plurality of phase ranges (P 0 , P 1 , P 2 , and P 3 ), determine a relation between said intensity-modulated light from said light-emitting element and said intensity-modulated light received at said light-receiving element based upon a variation of said extracted light intensities, and output spatial information within said target space; a light-receiving element driving circuit ( 40 ; 40 A; 40 B) configured to output a plurality of light-receiving element driving signals D 2 which are out of phase relation from each other to said light-receiving element in order to activate said light-receiving element for each of said phase ranges; a detection signal generation circuit ( 20 ) configured to provide to said light-receiving element driving circuit a detection timing signal (D 1 ) for determination of a timing of generating said light-receiving element driving signal; and a timing synchronization circuit ( 70 ; 70 A; 70 B) configured to compare a cyclic variation associated with the output from said light-emitting element driving circuit with a cyclic variation determined by said detection timing signal, and modify at least one of said detection timing signal (D 1 ) and said lighting timing signal (E 1 ) in order to keep a constant phase difference between said cyclic variations.