Solid-State Imaging Electrode Overlap for Filterless Color Sensing
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Solution Overview
Problem
Solid-state imaging apparatuses face challenges in improving imaging characteristics due to reduced sensitivity and signal noise ratio caused by miniaturization of pixel size, leading to absorption of green and blue light by color filters in red pixels and the generation of false colors through interpolation processing.
Innovation Solution
A solid-state imaging element with a first electrode and a second electrode, where the electrodes overlap partially with an insulation layer in between, enhancing the transfer efficiency of charges generated by photoelectric conversion, allowing for improved imaging characteristics without the need for color filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is miniaturized to increase resolution, then the number of pixels increases, but sensitivity and signal-to-noise ratio are reduced
Solution Approach 1:
The first electrode is divided into multiple electrodes arranged in a matrix pattern, where each electrode corresponds to a specific pixel region. This segmentation allows each electrode to independently collect charges from its corresponding pixel, maintaining high collection efficiency even as pixel size decreases and pixel density increases.
Solution Approach 2:
The patent introduces a vertical stacking dimension by placing the first electrode matrix above the photoelectric conversion layer with a predetermined gap, rather than having electrodes in the same plane. This three-dimensional arrangement allows charges to be collected vertically from beneath, increasing collection efficiency without occupying lateral pixel space and thereby maintaining sensitivity despite pixel miniaturization.
2Loss of information
If color filters are used for colorization, then color information is obtained, but green and blue light are absorbed in red pixels, reducing sensitivity
Solution Approach 1:
The patent removes color filters from the optical path entirely, replacing them with a direct photoelectric conversion approach. The photoelectric conversion layer converts incident light of all wavelengths directly into charges, which are then collected by the electrode matrix. This extraction of the color filter component eliminates the absorption losses that would otherwise reduce sensitivity.
Solution Approach 2:
The patent replaces the optical-mechanical color filter system with an electrical detection system. Instead of using physical filters to separate wavelengths optically, the system uses the photoelectric conversion layer to generate charges from all wavelengths, followed by electrical signal processing to extract color information, thereby substituting an optical-mechanical approach with an electrical one that maintains higher sensitivity.
3Loss of information
If interpolation processing is performed between pixels, then color signals are generated, but false colors are produced
Solution Approach 1:
The electrode is segmented into multiple independent electrodes arranged in a matrix, with each electrode directly corresponding to a pixel location. This segmentation enables direct charge collection at each pixel without requiring interpolation between adjacent pixels, as each pixel has its own dedicated collection electrode. The segmented electrode structure provides spatially resolved color information that eliminates interpolation artifacts and false colors.
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 improves the transfer efficiency of charges and enhances imaging characteristics by eliminating potential barriers between electrodes, thereby reducing noise and improving image quality.
Implementation Method 1
a photoelectric conversion layer provided between the first electrode and the second electrode
Implementation Method 2
the first electrode has, at least in a portion, an overlap section where the plurality of electrodes overlap each other with a first insulation layer interposed therebetween. This makes it possible to improve transfer efficiency of charges generated by photoelectric conversion
Data Source
AI summary
A solid-state imaging element according to an embodiment of the present disclosure includes a first electrode including a plurality of electrodes, a second electrode opposed to the first electrode, and a photoelectric conversion layer provided between the first electrode and the second electrode, and the first electrode has, at least in a portion, an overlap section where the plurality of electrodes overlap each other with a first insulation layer interposed therebetween.