CMOS Image Sensor Pixel Layout for Accurate Phase Detection
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Solution Overview
Problem
In solid-state imaging devices with two photoelectric conversion devices under a single on-chip lens, output mixing reduces phase difference detection accuracy, and physical separation units interfere with photoelectric conversion, causing sensitivity loss and image quality degradation.
Innovation Solution
A solid-state imaging device with a pixel array unit featuring inter-pixel separation and light blocking units that protrude in a projecting shape to form a projection portion, improving phase difference detection accuracy while minimizing image degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a physical separation unit is provided between two photoelectric conversion devices, then output mixing is prevented and phase difference detection accuracy is improved, but the separation unit interferes with photoelectric conversion and reduces sensitivity
Solution Approach 1:
The pixel is divided into multiple photoelectric conversion devices (first and second photoelectric conversion devices) that are spatially separated. This segmentation allows each device to independently convert light without output mixing, improving phase difference detection accuracy while maintaining photoelectric conversion functionality through proper spatial arrangement
Solution Approach 2:
Different regions of the pixel are assigned different functions: the first and second photoelectric conversion devices are positioned to receive light for phase difference detection, while a third photoelectric conversion device is positioned to receive light for image capture. This local differentiation allows the system to achieve both accurate phase difference detection and maintain photoelectric conversion sensitivity without interference
2Adaptability or versatility
If multiple photoelectric conversion devices are embedded under one on-chip lens, then pupil-division is achieved and phase difference detection is enabled, but output mixing occurs and detection accuracy is reduced
Solution Approach 1:
The pixel is segmented into multiple photoelectric conversion devices with distinct spatial positions under a single on-chip lens. The first and second devices are positioned to capture divided pupil information for phase difference detection, while the third device is positioned to capture light for image formation, preventing output mixing while maintaining pupil-division capability
Solution Approach 2:
The on-chip lens acts as an intermediary that directs light to different photoelectric conversion devices based on their spatial positions. This intermediary structure enables pupil-division while preventing direct output mixing between devices, as each device receives specifically directed light paths
3Adaptability or versatility
If light-blocking structures are used for pupil-division, then phase difference detection is enabled, but information from blocked pixels cannot be used and interpolation is required
Solution Approach 1:
The patent replaces the mechanical light-blocking system with a photoelectric conversion-based system. Instead of blocking light to achieve pupil-division, the invention uses multiple photoelectric conversion devices positioned to naturally receive divided light paths. This substitution eliminates information loss from blocked pixels while maintaining pupil-division capability for phase difference detection
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
Enhances phase difference detection accuracy by preventing output mixing and maintaining image quality by physically separating photoelectric conversion areas without interfering with the conversion process.
Implementation Method 1
a plurality of photoelectric conversion devices being formed with respect to one on-chip lens in each of the plurality of pixels
Data Source
AI summary
The present technology relates to a solid-state imaging device and an electronic apparatus capable of improving the accuracy of phase difference detection while suppressing degradation of a picked-up image. There is provided a solid-state imaging device including: a pixel array unit, a plurality of pixels being two-dimensionally arranged in the pixel array unit, a plurality of photoelectric conversion devices being formed with respect to one on-chip lens in each of the plurality of pixels, a part of at least one of an inter-pixel separation unit formed between the plurality of pixels and an inter-pixel light blocking unit formed between the plurality of pixels protruding toward a center of the corresponding pixel in a projecting shape to form a projection portion. The present technology is applicable to, for example, a CMOS image sensor including a pixel for detecting the phase difference.