Patent ID: 7645997

Claim:
A method of determining a relative position of a photodetection event, the method comprising: providing a substantially square photodetector having terminals T A , T B , T C , and T D at its corners, wherein said terminals T A and T C are diagonally opposite to each other, and wherein said terminals T B and T D are diagonally opposite to each other; measuring signals A, B, C, and D from terminals T A , T B , T C , and T D , respectively, responsive to said photodetection event; computing a first relative diagonal position X′ P of said photodetection event from said signals B and D; computing a second relative diagonal position Y′ P of said photodetection event from said signals A and C; computing a relative orthogonal X-Y position of said photodetection event from said relative diagonal positions X′ P and Y′ P ; providing said relative orthogonal X-Y position of said photodetection event as an output.