Abstract: In one embodiment, apparatus for integrating a quantity of light is provided with a photosensor, an integration capacitor, and a transfer amplifier. The transfer amplifier has i) an input coupled to receive a voltage determined by the integration capacitor, and ii) an output. The apparatus is further provided with a first switch to pull the integration capacitor to a precharge voltage, and a second switch to couple the integration capacitor to the photosensor, to discharge the integration capacitor in proportion to a quantity of light that is incident on the photosensor. Other embodiments are also disclosed.

Abstract: In one embodiment, light having a first spectrum is filtered from a mixed light. Light having a second spectrum, different from the first spectrum, is also filtered from the mixed light. An intensity of the light having the first spectrum, and an intensity of the light having the second spectrum, are then sensed. From the sensed intensities of the lights having the first and second spectrums, an intensity of light having a third spectrum is estimated.

Abstract: In one embodiment, a light measurement is acquired from each of a plurality of illumination zones. Each light measurement is digitized, and values derived from the digitized light measurements are stored, proximate to where the light measurements are acquired. The values derived from the digitized light measurements are then transmitted to a central control system, and light emitted by the illumination zones is regulated based on determinations made by the central control system. In some cases, the light measurements may be acquired and transmitted via a light sensor package having: a light sensor providing an analog output proportional to received light; an analog-to-digital converter to convert the analog output of the light sensor to a digital value; a memory to store a value derived from the digital value; and an addressable communication interface to transmit the stored value to an external control system.

Abstract: The color sensing circuit includes a light detector to receive light and to generate a signal that is dependent on the received light. The light detector includes a first electrode coupled to a first node and a second electrode coupled to a second predetermined signal. A storage device is provided that includes a first node and a second node coupled to the second predetermined signal. A first switch is provided that selectively couples the first node with the first electrode of the storage device based on a charge control signal. A signal processing circuit is provided that includes a first electrode and an output to generate an output signal that represents the light received by the light detector. A second switch is also provided that selectively couples the first electrode of the storage device with the first electrode of the signal processing circuit based on an evaluate control signal. The signal processing circuit selectively asserts the charge control signal and evaluate control signal.

Abstract: In one embodiment, light having a first spectrum is filtered from a mixed light. Light having a second spectrum, different from the first spectrum, is also filtered from the mixed light. An intensity of the light having the first spectrum, and an intensity of the light having the second spectrum, are then sensed. From the sensed intensities of the lights having the first and second spectrums, an intensity of light having a third spectrum is estimated.

Abstract: In one embodiment, a user-selected color point is received. RGB tristimulus values are then derived for the color point. It is also determined whether the user-selected color point is outside a color selection range of the LED light source and, if so, an error flag is set. Pulse width modulated signals for a plurality of LED drivers for the LED light source are also generated. In another embodiment, tristimulus values representing a color of light produced by an LED light source are received. The received tristimulus values are then compared to tristimulus values corresponding to a user-identified color point. In response to the comparison, pulse width modulated signals are generated for a plurality of LED drivers for the LED light source. After a predetermined number of repetitions of these actions, an error flag is set if the user-selected color point has not been achieved by the LED light source.

Abstract: In one embodiment, light is detected using a photodetector. If the detected light is causing the photodetector to saturate, one or more liquid crystal light valves are adjusted to filter the amount of incident light on the photodetector.

Abstract: Optical feedback for controlling color of light from a light source is provided. Incident optical energy of the light is detected as a function of discrete steps of wavelength. For each discrete step of wavelength, an X, Y and Z tristimulus subvalue is produced. All the X, Y and Z tristimulus subvalues for all the discrete steps are summed together to produce an X, Y and Z tristimulus value for the light. The X, Y and Z tristimulus values are used as feedback in controlling color of the light generated by the light source.

Abstract: Method and apparatus for compensating for variations in the output signal of a color sensor due to varying temperature of the color sensor. The color sensor receives light and generates an output signal that is based on the received light. The temperature compensation mechanism measures the temperature of the color sensor and uses the measured temperature to selectively adjust the output signal of the color sensor to generate a compensated output signal that is not dependent on temperature of the color sensor.