Multi-Photodetector Pixel Structure for Miniaturized Imaging
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Solution Overview
Problem
Current image sensors face challenges in miniaturization due to the multiplicity of different types embedded in the same device, which affects their compatibility with modern electronic device constraints.
Innovation Solution
The image sensor design incorporates a pixel structure with three photodetectors (A, B, and C) per pixel, each with its own read circuit, fabricated on a CMOS substrate, allowing for efficient integration and operation in various modes such as time-of-flight and global shutter, enabling multiple functionalities within the same matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple different types of image sensors are embedded in the same device, then the device can perform multiple imaging functions (color, infrared, depth measurement), but the device size increases and compatibility with miniaturization constraints deteriorates
Solution Approach 1:
The patent combines multiple photodetector types (first photodetectors for visible light, second photodetectors for infrared, and third photodetectors for depth measurement) into a single pixel structure on one semiconductor substrate. This merging approach integrates multiple imaging functions that would traditionally require separate sensors, thereby reducing overall device volume while maintaining versatility.
Solution Approach 2:
Each pixel in the matrix is designed to perform multiple functions simultaneously through different photodetector types. The first photodetectors capture visible light for color imaging, second photodetectors detect infrared radiation for thermal or night vision, and third photodetectors measure depth via time-of-flight. This multi-functionality at the pixel level eliminates the need for multiple separate sensors.
2Adaptability or versatility
If multiple photodetectors are integrated in each pixel, then multiple imaging modes can be supported, but the manufacturing complexity increases
Solution Approach 1:
The pixel is segmented into distinct photodetector units (first, second, and third photodetectors) with dedicated readout circuits for each type. This segmentation allows each photodetector to be optimized for its specific function while maintaining a modular structure that simplifies the overall integration process. Each segment can be manufactured using standard CMOS processes, reducing manufacturing complexity despite the multi-functional requirement.
3Adaptability or versatility
If three photodetectors with read circuits are integrated per pixel, then time-of-flight and global shutter modes can be operated simultaneously, but the area occupied per pixel increases
Solution Approach 1:
The patent utilizes the third dimension (vertical stacking) by integrating photodetectors at different depths within the semiconductor substrate. The first, second, and third photodetectors are positioned at different vertical levels, allowing them to coexist within the same horizontal pixel footprint. This vertical integration dramatically reduces the area occupied per pixel while supporting multiple operating modes simultaneously.
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
This design enhances the image sensor's ability to operate in different imaging modes without loss of resolution, addressing miniaturization constraints and enabling integration of multiple functionalities in a single matrix, thus improving compatibility with modern electronic devices.
Implementation Method 1
a first photodetector (12A) capable of detecting photons incident on the pixel in the visible spectrum... a second photodetector (12B) capable of detecting photons incident on the pixel in the infrared spectrum
Implementation Method 2
a microlens (18) located directly above each color filter (30)... Each microlens (18) has a diameter substantially equal, preferably equal, to the side of the square jointly formed by the first and second photodetectors that it covers
Data Source
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AI summary
The present description relates to a pixel (10, 12, 14, 16) comprising a CMOS support (8) and at least two organic photodetectors (10A, 10B, 10C, 12A, 12B, 12C, 14A, 14B, 14C, 16A, 16B, 16C), in which a single lens (18) is directly above said organic photodetectors.