Unified Image-Depth Pixel Structure With Vertical Transfer Gates
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Solution Overview
Problem
Existing image and depth sensors face challenges due to the structural differences between image pixels and depth pixels, leading to inefficiencies when integrated on the same semiconductor substrate, such as the need for distinct pixel types and modes of operation for image and depth data acquisition.
Innovation Solution
A sensor design featuring an array of identical pixels with a doped semiconductor substrate, where each pixel includes a portion laterally delimited by a vertical insulation structure, multiple doped regions, and transfer gates, allowing for the selective acquisition of image or depth data by controlling the transfer gates and readout circuits to operate in rolling shutter or global shutter modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If image pixels and depth pixels are integrated on the same semiconductor substrate, then the sensor can acquire both images and depth maps, but the structural differences between image pixels and depth pixels cause various problems and reduce integration efficiency
Solution Approach 1:
The patent implements a pixel array where all pixels are identical in structure, capable of performing both image acquisition and depth map acquisition functions. The same pixel structure with photodetectors, transfer gates, and readout circuits handles both functionalities by controlling the transfer gates in different modes, eliminating the need for separate image pixels and depth pixels with different structures.
Solution Approach 2:
The patent merges the previously separate image pixel structure and depth pixel structure into a single unified pixel design. The pixel array uses identical pixels for both functions, combining what were previously distinct components into one integrated structure that operates in different modes depending on the acquisition type.
2Reliability
If distinct pixel types are used for image and depth acquisition, then each pixel type can be optimized for its specific function, but the integration on the same substrate becomes inefficient and increases device complexity
Solution Approach 1:
The patent creates universal pixels that perform both image and depth acquisition functions. Instead of having specialized image-optimized pixels and depth-optimized pixels, the same pixel structure handles both tasks by controlling the transfer gates differently, maintaining functional capability while improving integration efficiency.
Solution Approach 2:
The patent changes the operational parameters of the identical pixel structure to achieve different functions. By controlling the transfer gates in different states and sequences, the same physical pixel structure adapts to perform either image acquisition or depth map acquisition, optimizing both functions through parameter control rather than structural differentiation.
3Measurement precision
If separate image pixels and depth pixels are used, then image quality and depth accuracy can be independently optimized, but power consumption increases and simultaneous illumination for depth map acquisition is not possible
Solution Approach 1:
The patent uses identical pixels for both image and depth acquisition, allowing the sensor to maintain high measurement precision for both functions while reducing power consumption. The unified pixel structure eliminates redundant circuitry and allows simultaneous illumination for depth maps, as the same pixels are used for both purposes rather than requiring separate dedicated depth pixels.
Solution Approach 2:
The patent enables continuous and simultaneous operation of image and depth acquisition using the same pixel array. By controlling the transfer gates appropriately, the sensor can perform depth map acquisition with simultaneous illumination while maintaining image acquisition capabilities, ensuring continuous useful action without the power overhead of separate pixel systems.
4Productivity
If identical pixels are used for both image and depth acquisition, then integration efficiency improves and power consumption reduces, but the pixels must be controlled in different modes to achieve both functions
Solution Approach 1:
The patent implements identical pixels that serve dual purposes through controlled operation of transfer gates. The same pixel structure with transfer gates handles both image and depth acquisition by switching between different control modes, achieving high integration efficiency while managing control complexity through a unified gate control mechanism.
Solution Approach 2:
The patent uses dynamic control of the transfer gates to enable the identical pixels to switch between image acquisition mode and depth map acquisition mode. The transfer gates are dynamically controlled with different timing and states depending on the desired function, allowing the static pixel structure to perform dynamic, multi-functional operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the acquisition of either color or black-and-white images and depth maps using identical pixels, improving integration efficiency and reducing power consumption by allowing simultaneous illumination for depth map acquisition, thus overcoming the limitations of traditional sensors.
Implementation Method 1
a first vertical transfer gate surrounding the first region; and at least two assemblies. Each assembly comprises: a second region of the first conductivity type more heavily doped than the substrate, and a second vertical transfer gate arranged opposite a corresponding portion of the first transfer gate
Implementation Method 2
An image sensor enables to acquire images, for example, color or black-and-white, of a scene
Implementation Method 3
a doped semiconductor substrate of a first conductivity type, each pixel comprising: a portion of the substrate laterally delimited by a vertical insulation structure
Data Source
AI summary
A sensor includes pixels supported by a substrate doped with a first conductivity type. Each pixel includes a portion of the substrate delimited by a vertical insulation structure with an image sensing assembly and a depth sensing assembly. The image sensing assembly includes a first region of the substrate more heavily doped with the first conductivity type and a first vertical transfer gate completely laterally surrounding the first region. Each of the depth sensing assemblies includes a second region of the substrate more heavily doped with the first conductivity type a second vertical transfer gate opposite a corresponding portion of the first vertical transfer gate. The second region is arranged between the second vertical transfer gate and the corresponding portion of the first vertical transfer gate.