Solid-State Imaging Element Electrode Embedding for Charge Transfer
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Solution Overview
Problem
Solid-state imaging apparatuses face challenges in charge transfer efficiency due to reduced photon sensitivity and false color generation caused by miniaturization of pixel size and the use of color filters, leading to decreased signal-to-noise ratio and interpolation errors.
Innovation Solution
A solid-state imaging element with a photoelectric conversion layer, insulation layer, and a pair of electrodes where the first electrode is embedded in the insulation layer to facilitate two-dimensional charge movement, improving charge transfer efficiency by allowing independent voltage application to the readout and accumulation electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If pixel size is miniaturized to increase resolution, then the number of pixels increases, but charge transfer efficiency decreases and sensitivity is reduced
Solution Approach 1:
The electrode is divided into a first electrode and a second electrode that are independently controllable. The first electrode is embedded in the insulation layer to extract charges vertically, while the second electrode is positioned on the opposite side to extract charges horizontally, enabling segmented charge extraction paths that improve transfer efficiency in miniaturized pixels
Solution Approach 2:
The first electrode is embedded within the insulation layer at a depth that allows it to access charges from the photoelectric conversion layer, creating a three-dimensional electrode configuration. This vertical embedding adds a depth dimension to charge extraction, enabling efficient charge collection from reduced-size pixels
2Measurement precision
If color filter is used for colorization, then color separation is achieved, but sensitivity is reduced due to light absorption
Solution Approach 1:
The pixel is segmented into multiple photoelectric conversion regions with different spectral sensitivities (red, green, blue regions). Each region is associated with independently controllable electrodes, allowing simultaneous photoelectric conversion of multiple wavelengths without color filter absorption losses
Solution Approach 2:
The photoelectric conversion layer is designed to simultaneously convert multiple wavelengths of light in different spatial regions. The multi-electrode configuration allows universal charge extraction for all color channels (R, G, B) through the same photoelectric conversion layer, eliminating the need for wavelength-selective color filters
3Loss of information
If interpolation processing is performed between pixels, then false colors are generated, but color accuracy deteriorates
Solution Approach 1:
Each pixel is segmented into multiple independently controllable photoelectric conversion regions (red, green, blue regions) with dedicated electrode control. This allows direct measurement of all color components at each pixel location, eliminating the need for interpolation and preventing false color generation
4Device complexity
If single electrode configuration is used, then device complexity is reduced, but charge transfer efficiency decreases
Solution Approach 1:
The electrode system is segmented into a first electrode embedded in the insulation layer and a second electrode on the opposite side, with independent voltage control. This segmentation enables separate control of charge extraction paths, improving transfer efficiency while maintaining manageable device complexity through systematic design
Solution Approach 2:
The electrodes are configured to apply voltages that can be dynamically adjusted to control charge movement. The first and second electrodes can independently apply electric fields to guide charges along optimal paths, enabling dynamic optimization of charge transfer efficiency based on operating conditions
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 charge transfer efficiency and reduces reset noise, improving imaging quality by enabling complete depletion of charge accumulation sections and reducing false color artifacts.
Implementation Method 1
a photoelectric conversion layer; photoelectrically converting light
Data Source
AI summary
A solid-state imaging element according to an embodiment of the present disclosure includes: a photoelectric conversion layer; an insulation layer provided on one surface of the photoelectric conversion layer and having a first opening; and a pair of electrodes opposed to each other with the photoelectric conversion layer and the insulation layer interposed therebetween. Of the pair of electrodes, one electrode provided on a side on which the insulation layer is located includes a first electrode and a second electrode each of which is independent, and the first electrode is embedded in the first opening provided in the insulation layer to be electrically coupled to the photoelectric conversion layer.