Photoelectric Conversion Element Spatial Separation Sensitivity
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Solution Overview
Problem
Conventional CMOS linear image sensors suffer from reduced sensitivity due to the area occupied by pixel circuits, particularly in reduction optical systems, and struggle with high-speed color reading due to shared pixel circuits among colors.
Innovation Solution
A photoelectric conversion element with light-receiving elements in a light-receiving area and pixel circuits in a non-light-receiving area, allowing for independent operation and maximizing the photo diode area, enabling simultaneous reading of multiple colors and increased pixel pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pixel circuits are formed within the pixel area, then the device complexity is reduced and integration is improved, but the photo diode area is limited and sensitivity deteriorates
Solution Approach 1:
The patent moves the pixel circuit from the two-dimensional pixel plane to a third dimension by forming it in a non-light-receiving area below the light-receiving layer. This spatial separation allows the photo diode to occupy the entire light-receiving area while the circuit operates in a separate region, resolving the contradiction between integration and sensitivity.
Solution Approach 2:
The patent divides the sensor structure into distinct functional layers: a light-receiving area containing only photo diodes for maximum light capture, and a non-light-receiving area containing pixel circuits for signal processing. This segmentation allows each component to be optimized independently without compromising the other.
2Device complexity
If a common pixel circuit is shared among multiple colors (R, G, B), then the device complexity is reduced, but the reading speed is limited and high-speed color reading cannot be realized
Solution Approach 1:
The patent assigns dedicated pixel circuits to each color channel (R, G, B) rather than sharing a common circuit. This segmentation allows parallel processing of multiple color signals simultaneously, eliminating the sequential reading bottleneck and enabling high-speed color image acquisition.
Solution Approach 2:
By providing separate pixel circuits for each color, the system can continuously process all color channels in parallel without waiting for sequential processing, maintaining continuous useful action across all color channels and achieving high-speed reading.
3Area of moving object
If the pixel size is reduced for reduction optical system, then the device miniaturization is achieved, but the photo diode area becomes even more limited and sensitivity deteriorates further
Solution Approach 1:
The patent relocates the pixel circuit to a non-light-receiving area in a different spatial zone, allowing the photo diode within each miniaturized pixel to maintain its light-receiving area without being encroached upon by circuit components. This enables small pixel sizes while preserving sensitivity.
Solution Approach 2:
The patent creates different functional zones with distinct properties: the light-receiving area is optimized for maximum light capture with no circuit interference, while the non-light-receiving area is optimized for circuit operation. This local quality differentiation allows miniaturization without sensitivity loss.
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 configuration enhances sensitivity and allows for faster image reading by maximizing the photo diode area and eliminating the need for shared pixel circuits, enabling simultaneous reading of R, G, and B colors without color shift.
Implementation Method 1
a plurality of light-receiving elements that generates a charge for each pixel according to an amount of received light
Data Source
AI summary
A photoelectric conversion element comprises: a plurality of light-receiving elements that generates a charge for each pixel according to an amount of received light; and a plurality of pixel circuits that operates so as to derive the charge generated by the plurality of light-receiving elements from the plurality of light-receiving elements for each pixel. The plurality of light-receiving elements is arranged in a light-receiving area that receives light from outside, and the plurality of pixel circuits is provided in a non-light-receiving area that does not receive the light from outside.