Image Sensor Selective Light Shielding for Reference Pixels
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Solution Overview
Problem
Current image sensors face challenges in achieving improved electrical characteristics and accuracy, particularly in consumer electronic devices, where high performance and low power consumption are required, and there is a need for enhanced light management and noise reduction.
Innovation Solution
The image sensor design incorporates a light shield layer with openings to allow light to reach only the light-receiving pixels, while shielding reference pixels, and features a micro-lens array that overlaps both types of pixels, along with a semiconductor substrate and photoelectric conversion elements, to optimize light transmission and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference pixels are exposed to light for signal generation, then signal strength is improved, but noise from unwanted light increases
Solution Approach 1:
The patent applies local quality by creating spatially differentiated light exposure conditions: light-receiving pixels are exposed to light through openings in the light shield layer, while reference pixels are shielded from light. This selective light exposure allows each pixel type to perform its specific function optimally - light-receiving pixels generate signal while reference pixels measure dark current without light interference.
Solution Approach 2:
The patent segments the pixel array into functionally distinct regions: light-receiving pixels for signal generation and reference pixels for dark current measurement. The light shield layer with selective openings further segments the light path, directing light only to light-receiving pixels while blocking it from reference pixels, thereby eliminating cross-contamination of light exposure between the two functions.
2Use of energy by moving object
If micro-lenses are added to improve light transmission, then light management is enhanced, but device complexity increases
Solution Approach 1:
The micro-lenses in the patent serve multiple functions simultaneously: they focus incident light onto the photoelectric conversion elements, enhance light transmission efficiency, and work in conjunction with the light shield layer to direct light selectively to light-receiving pixels. This multi-functionality improves light management without requiring additional separate components.
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 accuracy and efficiency of image sensors by providing improved light management and noise reduction, leading to better performance in consumer electronic devices with reduced power consumption and compact size.
Implementation Method 1
a photoelectric conversion layer including a plurality of first photoelectric conversion elements and a plurality of second photoelectric conversion elements
Implementation Method 2
an array of micro-lenses on the photoelectric conversion layer, each of the micro-lenses overlapping at least one of the first photoelectric conversion elements and at least one of the second photoelectric conversion elements
Data Source
AI summary
An image sensor includes a photoelectric conversion layer including a plurality of first photoelectric conversion elements and a plurality of second photoelectric conversion elements adjacent to the first photoelectric conversion elements. A light shield layer shields the second photoelectric conversion elements and has respective openings therein that provide light transmission to respective ones of the first photoelectric conversion elements. The image sensor further includes an array of micro-lenses on the photoelectric conversion layer, each of the micro-lenses overlapping at least one of the first photoelectric conversion elements and at least one of the second photoelectric conversion elements.