US Patent 8174205 Lighting devices and methods for lighting

A lighting device comprises groups of solid state light emitters, a sensor and circuitry. If the emitters are illuminated, the sensor is exposed to combined light from the groups, and senses only a portion of the combined light. The circuitry adjusts current applied to at least one of the emitters based on an intensity of the light sensed. Also, a device comprising emitters, a circuit board and a sensor, at least one of the emitters being positioned on the first circuit board and the sensor being spaced from the circuit board. Also, a lighting device comprising emitters, a sensor, and circuitry which adjusts current applied an emitters based on detection by the first sensor, the circuitry comprising a differential amplifier circuit. Also, a lighting device, comprising light emitters and circuitry which adjusts current applied to only some of the emitters based on ambient temperature. Also, methods of lighting.