device for measurement of a ljuspunkts mode with integrated function to eliminate the effect of stray light

摘要

PCT No. PCT/SE95/01021 Sec. 371 Date Mar. 14, 1997 Sec. 102(e) Date Mar. 14, 1997 PCT Filed Sep. 11, 1995 PCT Pub. No. WO96/08702 PCT Pub. Date Mar. 21, 1996A photodetector for measuring the position of an incident light beam on an active surface area of the detector includes an inactive area and a concentric stray light absorbing area, both of which outwardly surround the light-absorbing active area. All light incident on the stray light-absorbing area and the inactive area will generate a photoelectric current which is conducted to an earth ground via an electrode in the stray-light area. An electrical signal from the active area representing a position of the measured light in the active area will be unaffected by any stray light incident on the detector externally of the active area.