Solid state image sensor suitable for touch screens
AssigneeSTMicroelectronics (Research & Development) Limited
InventorJeffrey M. Raynor
Life of this patent
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Abstract
Disclosed is a sensor apparatus comprising a plurality of pixels, a digital to analog converter for providing a ramp signal, A comparator for comparing the output level of each pixel to said ramp signal, and memory for storing the digital value that corresponds to said output level for each pixel, the sensor apparatus thereby converting the analog output level of each pixel to a digital value. The apparatus operates by providing an analog output that is sourced from the digital to analog converter used to provide said ramp signal.
Claims19
Apparatus including a sensor, comprising:
- a plurality of pixels,
- a digital to analog converter configured to provide a ramp signal,
- at least one comparator configured to compare an analog output level of each pixel to said ramp signal, and
- at least one memory configured to store the digital value that corresponds to said output level for each pixel, said sensor apparatus thereby converting the analog output level of each pixel to a digital value,
- wherein said sensor is operable to provide an analog output, said analog output being sourced from said digital to analog converter used to provide said ramp signal.
The apparatus comprising a plurality of pixels, the analog output level of each pixel being converted to a digital value, wherein said sensor is further operable to provide an analog output corresponding to said digital values.
Apparatus including a sensor, comprising:
- a pixel operable to generate an analog output level,
- a digital to analog converter operable in a first mode to provide a ramp signal and operable in a second mode to provide an analog output signal,
- a comparison circuit configured to compare the analog output level of each pixel to said ramp signal provided by said digital to analog converter when operating in the first and generate a digital output level, and
- a memory configured to store the digital output level,
- wherein said digital to analog converter, when operating in the second mode, receives the digital output level from the memory and converts the received digital output level to the analog output signal.
A method, comprising:
- generating an analog output level from a pixel;
- using a digital to analog converter to provide an analog ramp signal;
- comparing the analog output level to said ramp signal;
- producing, from the comparison of the analog output level to said ramp signal a digital output level;
- storing the digital output level in a memory;
- and
- using said digital to analog converter to convert the stored digital output level to an analog output signal.
Dependencies are inferred from the claim text.