H04N 25/772

Definition

(Für diese Definition ist die deutsche Übersetzung noch nicht abgeschlossen)

Addressed sensors with pixels or group of pixels comprising A/D, V/T, V/F, I/T or I/F converters. The converters should be at least partially implemented in the pixel array.

Stacked chip structures in which a pixel or a group of pixels is connected to an A/D converter implemented on a different chip.

This group does not cover image sensors in which a column of pixels is connected to an A/D converter.

A/D converters can be of any type and can be specifically designed for photoelectric pixel circuits and/or to work in combination with other pixel elements like transfer gates, reset gates, source followers, etc. A/D converters can be used to convert the image signal from the pixel to a digital value. A/D converters can be used to generate a digital value for controlling different characteristics of the pixel like its exposure time or sensitivity.

Some pixels circuits comprising converters provide an analogue and a digital output or a multiplexed digital and analogue output.

The converters convert current or voltage levels to signals with different frequency – current to frequency (I/F) converter or use voltage-controlled oscillator to perform voltage to frequency conversion (V/F).

The converters convert the signal from the photo sensor to a time-dependent signal (V/T or I/T converter). These circuits are sometimes called ADC using pulse width modulation (PWM). A comparator measures the duration of the exposure time needed for the pixel to reach a predetermined threshold. The duration of the pulse corresponds to the pixel level. The duration of the pulse can be converted to a digital value by using a counter or to analogue signal using a ramp signal.

The converters are ADC converters that count the number of exposure periods. These circuits are sometimes also called voltage to frequency converters or ADC using pulse frequency modulation (PFM). The duration of each exposure period is defined by a control circuit that determines when the signal from the photodiode reaches a predetermined threshold. The control circuit normally performs a reset operation and starts the new exposure period. Note that a part of or the entire control circuit can be implemented outside the pixel array.

The converters are part of photon counting pixels that generate one-bit signals corresponding to a detected photon, and the number of detected photons for a predetermined time is counted to provide a digital value (Details for such pixel circuits can be found in groups G01T 1/24, G01J 1/46 as a part of a radiation measuring system).

The converters are single slope ADCs (Details of single slope ADCs as such can be found in group H03M 1/56).

The converters are flash type ADCs.

The converters are sigma delta ADCs.

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