Light-trapping image sensors
Granted: January 2, 2024
Patent Number:
11862651
A light-trapping image sensor includes a pixel array and a lens array. The pixel array is formed in and on a semiconductor substrate and including photosensitive pixels each including a reflective material forming a cavity around a portion of semiconductor material to at least partly trap light that has entered the cavity. The cavity has a ceiling at a light-receiving surface of the semiconductor substrate, and the ceiling forms an aperture for receiving the light into the cavity. The…
Shallow trench isolation (STI) structure for CMOS image sensor
Granted: January 2, 2024
Patent Number:
11862509
A shallow trench isolation (STI) structure and method of fabrication includes forming a shallow trench isolation (STI) structure having a polygonal shaped cross-section in a semiconductor substrate of an image sensor includes a two-step etching process. The first step is a dry plasma etch that forms a portion of the trench to a first depth. The second step is a wet etch process that completes the trench etching to the desired depth and cures damage caused by the dry etch process. A CMOS…
Flare-suppressing image sensor
Granted: January 2, 2024
Patent Number:
11860383
Embodiments disclosed herein reduce petal flare. A flare-suppressing image sensor includes a plurality of pixels including a first set of pixels and a second set of pixels. The flare-suppressing image sensor further includes plurality of microlenses, where each microlens is aligned to a respective one of the first set of pixels. The flare-suppressing image sensor further includes plurality of sub-microlens, where each microlens array is aligned to a respective one of the second set of…
HV driver for rolling clamp in image sensor
Granted: December 12, 2023
Patent Number:
11843884
An imaging system includes a pixel array with pixel circuits, each including a photodiode, a floating diffusion, a source follower transistor, and a row select transistor. The imaging system further includes rolling clamp (RC) drivers, each coupled to a gate terminal of a row select transistor of one of the pixel circuits and each including first and second PMOS transistors coupled between a clamp voltage and the gate terminal of the row select transistor of the one of the pixel…
Optical fingerprint sensor with spoof detection and associated method
Granted: December 12, 2023
Patent Number:
11842563
An optical fingerprint sensor with spoof detection includes a plurality of lenses, an image sensor including a pixel array that includes a plurality of first photodiodes and a plurality of second photodiodes, and at least one apertured baffle-layer having a plurality of aperture stops, wherein each second photodiode is configured to detect light having passed through a lens and at least one aperture stop not aligned with the lens along an optical axis. A method for detecting spoof…
CMOS image sensor pixel for high dynamic range capturing
Granted: November 28, 2023
Patent Number:
11830894
An image sensor element includes a transfer transistor TX, a LOFIC select transistor LF, a photodiode PD, and a first overflow path OFP. The transfer transistor TX outputs a readout signal from a first end. The LOFIC select transistor LF includes a first end connected to a second end of the transfer transistor TX, and a second end connected to a capacitor. The photodiode PD is connected in common to a third end of the transfer transistor and a third end of the LOFIC select transistor LF.…
CMOS image sensor with LED flickering reduction and low color cross-talk
Granted: November 7, 2023
Patent Number:
11810928
CMOS image sensor with LED flickering reduction and low color cross-talk are disclosed. In one embodiment, an image sensor includes a plurality of pixels arranged in rows and columns of a pixel array that is disposed in a semiconductor substrate. Each pixel includes a plurality of large subpixels (LPDs) and at least one small subpixel (SPD). A plurality of color filters are disposed over individual subpixels. Each individual SPD is laterally adjacent to at least one other SPD.
Pixel-array substrate
Granted: November 7, 2023
Patent Number:
11810931
A pixel-array substrate includes (i) a semiconductor substrate including a photodiode region and a floating diffusion region, and (ii) a vertical-transfer-gate structure that includes a trench and a gate electrode. The trench is defined by a bottom surface and a sidewall surface of the substrate each located between a front substrate-surface and a back substrate-surface thereof. The trench extends into the substrate. In a cross-sectional plane perpendicular to the front substrate-surface…
Pointed-trench pixel-array substrate and associated fabrication method
Granted: November 7, 2023
Patent Number:
11810940
A pointed-trench pixel-array substrate includes a floating diffusion region and a photodiode region formed in a semiconductor substrate. The semiconductor substrate includes, between a top surface and a back surface thereof, a sidewall surface and a bottom surface defining a trench extending into the semiconductor substrate away from a planar region of the top surface surrounding the trench. In a cross-sectional plane perpendicular to the top surface and intersecting the floating…
Endoscope imager and associated method
Granted: October 10, 2023
Patent Number:
11782256
An endoscope imager includes a system-in-package and a specularly reflective surface. The system-in-package includes (a) a camera module having an imaging lens with an optical axis and (b) an illumination unit. The system-in-package includes (a) a camera module having an imaging lens with an optical axis and (b) an illumination unit configured to emit illumination propagating in a direction away from the imaging lens, the direction having a component parallel to the optical axis. The…
Pixel-array substrate and associated method
Granted: October 10, 2023
Patent Number:
11784206
A pixel-array substrate includes a floating diffusion region and a first photodiode formed in a semiconductor substrate. A top surface of the semiconductor substrate defines a trench 1A and a trench 1B each (i) extending into the semiconductor substrate away from a planar region of the top surface between the trench 1A and the trench 1B and (ii) having a respective distal end, with respect to the floating diffusion region, located between the floating diffusion region and the first…
Method for passivating full front-side deep trench isolation structure
Granted: September 26, 2023
Patent Number:
11769779
A method for forming a deep trench isolation structure for a CMOS image sensor includes providing a trench that extends from a first side toward a second side of a semiconductor substrate. The trench has an opening on the first side and a bottom and sides. A conformal layer of B-doped oxide is deposited on the bottom and sides of the trench and is less than half a width of the trench leaving a depthwise recess in the trench. A second material is deposited on the conformal layer of…
Readout architecture for indirect time-of-flight sensing
Granted: September 26, 2023
Patent Number:
11770633
A time-of-flight sensor includes a pixel array of pixel circuits. A first subset of the pixel circuits is illuminated by reflected modulated light from a portion of an object. A second subset of the pixel circuits is non-illuminated by the reflected modulated light. Each pixel circuit includes a floating diffusion that stores a portion of charge photogenerated in a photodiode in response to the reflected modulated light. A transfer transistor transfers the portion of charge from the…
Trimming control circuit for current integration ramp DAC settling assist circuit
Granted: September 26, 2023
Patent Number:
11770634
A ramp generator includes an operational amplifier having an output to generate a ramp signal. An integration current source is coupled to a first input and a reference voltage is coupled to a second input of the operational amplifier. A feedback capacitor is coupled between the first input and the output of the operational amplifier. A monitor circuit is coupled to the first and second inputs of the operational amplifier to generate an output flag in response to a comparison of the…
High dynamic range CMOS image sensor pixel with reverse biased metal-insulator-metal lateral overflow integration capacitor for reduced image lag
Granted: September 19, 2023
Patent Number:
11765484
A pixel circuit includes a transfer transistor is coupled between a photodiode and a floating diffusion to transfer the image charge from the photodiode to the floating diffusion. A lateral overflow integration capacitor (LOFIC) includes an insulating region between a first metal electrode and a second metal electrode that is coupled to a first reset transistor and selectively coupled to the floating diffusion. A second reset transistor and a bias voltage source are coupled to the first…
Image sensor with on-chip occlusion detection and methods thereof
Granted: June 20, 2023
Patent Number:
11683598
An imaging system including an image sensor coupled to a controller to image an external scene is described. The controller includes logic storing instructions that when executed causes the imaging system to perform operations including capturing images, including a first image and a second image, of an external scene, and generating reduced representations of the images including a first reduced representation associated with the first image and a second reduced representation…
Resettle timing for low power pixel readout
Granted: June 20, 2023
Patent Number:
11683611
A pixel readout circuit includes an analog to digital converter coupled to the bitline output of the pixel circuit. A switch is coupled between the bitline output of the pixel circuit and a reference voltage. The switch is pulsed on and off a first time to settle the bitline to the reference voltage prior to an autozero operation of the analog to digital converter. The switch is pulsed on and off a second time to settle the bitline to the reference voltage after the autozero operation…
Image sensor with three readout approach for phase detection autofocus and image sensing pixels
Granted: June 20, 2023
Patent Number:
11683607
An imaging device includes a plurality of photodiodes arranged in a photodiode array to generate charge in response to incident light. The plurality of photodiodes includes first and second photodiodes. A shared floating diffusion receives charge transferred from the first and second photodiodes. An analog to digital converter (ADC) performs a first ADC conversion to generate a reference readout in response to charge in the shared floating diffusion after a reset operation. The ADC is…
Circuit and method for image artifact reduction in high-density, highpixel-count, image sensor with phase detection autofocus
Granted: June 20, 2023
Patent Number:
11683604
An image sensor includes an array of multiple-photodiode cells, each photodiode coupled through a selection transistor to a floating diffusion of the cell, the selection transistors controlled by respective transfer lines, a reset, a sense source follower, and a read transistor coupled from the source follower to a data line. The array includes phase detection rows with phase detection cells and normal cells; and a compensation row of more cells. In embodiments, each phase detection row…
Nine cell pixel image sensor with phase detection autofocus
Granted: June 20, 2023
Patent Number:
11683602
An imaging device includes a pixel array of 1×3 pixel circuits that include 3 photodiodes in a column. Bitlines are coupled to the 1×3 pixel circuits. The bitlines are divided into groupings of 3 bitlines per column of the 1×3 pixel circuits. Each column of the 1×3 pixel circuits includes a plurality of first banks coupled to a first bitline, a plurality of second banks coupled to a second bitline, and a plurality of third banks coupled to a third bitline of a respective grouping of…
