Devices and methods for obtaining three-dimensional shape information using polarization and time-of-flight detection pixel cells
Granted: January 9, 2024
Patent Number:
11871132
In some embodiments, an imaging system is provided. The imaging system comprises an image sensor, a light source, control circuitry, and function logic. The image sensor comprises a pixel array that includes a plurality of polarization pixel cells and a plurality of time-of-flight pixel cells. The light source is configured to emit light pulses to an object. The control circuitry is coupled to the light source and the pixel array, and is configured to synchronize a timing of the emission…
Signal-charge estimator and method
Granted: January 9, 2024
Patent Number:
11871129
A method for estimating a signal charge collected by a pixel of an image sensor includes determining an average bias that depends on the pixel's floating-diffusion dark current and pixel-sampling period. The method also includes determining a signal-charge estimate as the average bias subtracted from a difference between a weighted sum of a plurality of N multiple-sampling values each multiplied by a respective one of a plurality of N sample-weights.
Image sensor with elevated floating diffusion
Granted: January 9, 2024
Patent Number:
11869906
A pixel cell with an elevated floating diffusion region is formed to reduce diffusion leakage (e.g., gate induced drain leakage, junction leakage, etc.). The floating diffusion region can be elevated by separating a doped floating diffusion region from the semiconductor substrate by disposing an intervening layer (e.g., undoped, lightly doped, etc.) on the semiconductor substrate and beneath the doped floating diffusion region. For instance, the elevated floating diffusion region can be…
Thin, multi-lens, optical fingerprint sensor adapted to image through cell phone displays
Granted: January 9, 2024
Patent Number:
11869267
A multiple-lens optical fingerprint reader for reading fingerprints through a display has a spacer; and multiple microlenses with concave and convex surfaces in a microlens array, each microlens of multiple lenses focuses light arriving at that microlens from a finger adjacent the display through the spacer forms an image on associated photosensors on a photosensor array of an image sensor integrated circuit. A method of verifying identity of a user includes illuminating a finger of the…
Electrical isolation in pixel-array substrates using combination of doped semiconductor guard rings and overlapping isolation trenches
Granted: January 2, 2024
Patent Number:
11862678
A pixel-array substrate includes a semiconductor substrate with a pixel array, a back surface, and a front surface, and a guard ring formed of a doped semiconductor, enclosing the pixel array, and extending into the semiconductor substrate from the front surface, the back surface forming a trench extending into the semiconductor substrate, the trench overlapping the guard ring. A method for reducing leakage current into a pixel-array includes doping a semiconductor substrate to form a…
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…
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…
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…
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.…
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…
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…
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.
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…
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…
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…
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…
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…
