High dynamic range image sensor
An imaging device in accordance with the present disclosure comprises of a pixelated array of semiconductor detector elements, each of the pixels in the array having an in-pixel integrated circuit, the integrated circuit having a comparator, a readout decoder block, and an address arbitration control block. The readout decoder block reads out the integrated signals of the pixels. The address arbitration control block determines the pixel address of the pixels charging beyond a threshold voltage, the threshold exceedance determined by the comparator. The addressed pixels are provided a timestamp for each of the pixels integrating beyond the threshold voltage, the timestamp provided by an off-pixel time-to-digital converter (TDC), the value of the timestamp corresponding with the accumulated charge of the pixel.
1. A imaging device, the device comprising:
a pixelated array of detector elements, each of the pixels in the array having an integrated circuit, the integrated circuit having a comparator;
a readout decoder block, the readout decoder block reads out the integrated signals of the pixels;
an address arbitration control block, the address arbitration control block determines the pixel address of the pixels charging beyond a threshold voltage held by the comparator; and
wherein the addressed pixels are provided a timestamp by an off-pixel time-to-digital converter (TDC), the timestamp corresponding with the accumulated charge of the pixel, and wherein the address arbitration control block causes an offset voltage to be applied to the charge accumulation of pixels reaching the threshold voltage and the digital counter counts the number of times the offset is applied.
2. The device of claim 1 , wherein the integrated circuitry of the pixel to stops further charge accumulation for those pixels integrating beyond the threshold voltage, thereby holding the accumulated charge corresponding to the timestamp for readout by the readout decoder block.
3. The device of claim 1 , the device further comprising a digital counter.
4. The device of claim 3 , wherein the address arbitration control block resets pixels reaching the threshold voltage and the digital counter counts the number of times the pixel is reset.
5. The device of claim 1 , wherein digital logic stores a binary value corresponding to the threshold comparator status.
6. The device of claim 1 , wherein the comparator services a column of the pixels.
7. The device of claim 1 , wherein a plurality of time-to-digital converter is employed, the time-to-digital converters each associated with a column of pixels.
8. The device of claim 1 , wherein the voltage threshold is adjustable individually or in the aggregate.
9. The device of claim 1 , wherein the pixelated array is made from a material from the group consisting of indium gallium arsenide (InGaAs), silicon (Si), mercury cadmium telluride (HgCdTe), indium antimony (InSb), a group III-V, II-VI super lattice, quantum well detector, or any combinations thereof.
10. The device of claim 1 , wherein the pixelated array is made from semiconductor nanocrystals.
11. The device of claim 1 , wherein the device circuits and detector elements are made within the same substrate.
12. The device of claim 1 , wherein the pixelated array is thinned to less than 500 microns thickness and optical radiation enters the device from the side opposite from that containing circuits.
13. The device of claim 1 , wherein the circuits of the device are fabricated using CMOS processing.
14. The device of claim 1 , wherein the circuits of the device are fabricated in separate wafers and electrically connected.
15. The device of claim 1 , wherein the gain-bandwidth properties of a passive signal paths is adjustable, individually or in aggregate.
16. The device of claim 15 , wherein the gain-bandwidth properties of the passive path is adjusted based on the pixels reaching the threshold voltage.
17. The device of claim 1 , wherein the detector is sensitive to electromagnetic radiation regions from the group consisting the x-ray, ultraviolet, visible, near-infrared, short infrared, mid-infrared, long infrared, or combinations thereof including laser-lines within those regions.