Patent ID: 6307586
Filing Date: 2001-10-23
Classification: H01J,H04N

Abstract:
A camera comprising:a photocathode operable in a night mode wherein electrons are generated in response to incident light;a CMOS imager in spaced relation to said photocathode, said photocathode being positioned between the front side of said CMOS imager and an object being imaged, said CMOS imager comprising an array of pixels on the front surface of the CMOS imager for sensing electrons in said night mode;a power supply for energizing said photocathode in said night mode in response to a power supply control signal, said power supply comprising a gated power supply and said control signal comprising a gating signal having a duty cycle that increases as the light level decreases; anda power supply control circuit for providing said control signal to said power supply in response to the incident light level, wherein said power supply provides to said photocathode an average energy level that increases as the incident light level decreases.