Stacked Organic Image Sensor Pixels for High SNR Resolution
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Solution Overview
Problem
Existing solid-state imaging devices face challenges in achieving a high signal-to-noise (S/N) ratio at high sensitivity levels without compromising resolution, due to complex processes and high production costs associated with small pixel sizes and reduced photon sensitivity.
Innovation Solution
A solid-state imaging device is designed with a first photoelectric conversion unit having pixels tilted at 45 degrees and a second unit with Si semiconductor pixels arranged below, allowing for increased sensitivity and resolution through the use of organic and Si semiconductor photoelectric conversion units, along with filters and lenses to optimize light conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to increase the number of pixels, then resolution is improved, but sensitivity becomes much lower due to fewer photons entering each pixel per unit time
Solution Approach 1:
The patent transitions from a two-dimensional pixel arrangement to a three-dimensional stacked structure with multiple photoelectric conversion units at different depths. This vertical stacking allows each pixel to capture light across multiple wavelengths simultaneously, increasing photon capture efficiency without reducing spatial resolution.
Solution Approach 2:
The imaging device is segmented into multiple photoelectric conversion units, each optimized for specific wavelength ranges (e.g., green, red, blue). This segmentation allows specialized photoelectric conversion materials to be used for each unit, improving overall sensitivity while maintaining high resolution through the stacked architecture.
2Measurement precision
If three-layer vertical spectroscopy is implemented with RGB photoelectric conversion units stacked vertically, then resolution is improved with circular zone plate characteristics in wider Nyquist domain, but device complexity increases due to large numbers of transistors, floating diffusions, and plugs required for signal reading
Solution Approach 1:
The patent merges multiple photoelectric conversion functions into a stacked vertical structure where signal reading circuits can be shared across multiple photoelectric conversion units. This reduces the overall number of transistors and floating diffusions required compared to implementing separate reading circuits for each unit.
Solution Approach 2:
The stacked photoelectric conversion units are designed with universal signal reading mechanisms that can handle multiple wavelength channels through shared circuitry. This multi-functional approach reduces device complexity by eliminating redundant transistors and floating diffusions that would be required if each unit had dedicated reading circuits.
3Measurement precision
If pixel size is reduced, then the number of pixels increases, but production costs increase due to complicated processes
Solution Approach 1:
By moving to a three-dimensional stacked architecture, the patent achieves high resolution without requiring extremely small pixel dimensions. This allows manufacturing processes to operate at more manageable scales, reducing complexity and cost while still delivering high-resolution imaging performance.
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 achieves a high S/N ratio at high sensitivity levels without decreasing resolution, simplifies the production process, and reduces production costs by utilizing larger pixels and optimized light conversion techniques.
Implementation Method 1
a first photoelectric conversion unit that converts light of a first wavelength and has respective pixels two-dimensionally arranged... The light of the first wavelength is green light, and the first photoelectric conversion unit is formed with an organic photoelectric conversion film
Implementation Method 2
a second photoelectric conversion unit that converts light of a second wavelength and has respective pixels two-dimensionally arranged... The second photoelectric conversion unit and the third photoelectric conversion unit are formed with Si semiconductors
Data Source
AI summary
The present disclosure relates to a solid-state imaging device that can achieve a high S/N ratio at a high sensitivity level without any decrease in resolution, and to an electronic apparatus. In the upper layer, the respective pixels of a photoelectric conversion unit that absorbs light of a first wavelength are tilted at approximately 45 degrees with respect to a square pixel array, and are two-dimensionally arranged in horizontal directions and vertical directions in an oblique array. The respective pixels of a photoelectric conversion unit that is sensitive to light of a second or third wavelength are arranged under the first photoelectric conversion unit. That is, pixels that are √{square root over (2)} times as large in size (twice as large in area) and are rotated 45 degrees are arranged in an oblique array. The present disclosure can be applied to solid-state imaging devices that are used in imaging apparatuses, for example.