Imaging Sensor Transparent Area Pattern for SNR
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Solution Overview
Problem
Existing imaging sensors face challenges in achieving high signal-to-noise ratio (SNR), spatial resolution, contrast, and dynamic range across multiple spectral bands due to variations in photodiode sensitivity with wavelength, leading to sub-optimal use of well capacity and potential saturation.
Innovation Solution
The imaging sensor employs an array of identical light-detecting elements with a pattern of transparent areas that control the amount and direction of light reaching each element, allowing for tailored exposure times and preventing saturation, even in spectral bands with high sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If identical light-detecting elements are used across all spectral bands, then manufacturing simplicity is improved, but signal-to-noise ratio and dynamic range deteriorate due to varying photodiode sensitivity with wavelength
Solution Approach 1:
The patent applies local quality by making the transparent area size wavelength-dependent. Each light-detecting element has a transparent area size specifically tailored to its detected wavelength interval, compensating for varying sensitivity across the spectral range while maintaining identical photodiode structures throughout the array.
2Reliability
If exposure time is increased to improve signal-to-noise ratio in low sensitivity bands, then signal-to-noise ratio is improved, but saturation occurs in high sensitivity bands causing loss of spatial resolution and contrast
Solution Approach 1:
The patent resolves this contradiction by making the transparent area size wavelength-dependent. Elements detecting wavelengths with high sensitivity have smaller transparent areas that admit less light, preventing saturation even during long exposures. Elements detecting wavelengths with low sensitivity have larger transparent areas that admit more light, ensuring sufficient signal strength. This allows a single exposure time to achieve high signal-to-noise ratio across all spectral bands without saturation in any band.
3Reliability
If different sized micropixels are used to compensate for sensitivity variations, then signal-to-noise ratio is improved, but device complexity increases due to complex structure of differently shaped micropixels
Solution Approach 1:
The patent achieves local quality adjustment through the pattern of transparent areas rather than through complex micropixel structures. The transparent areas are selectively positioned and sized over the light-detecting elements, allowing control of light admission while maintaining a regular, manufacturable array structure with identical photodiodes throughout.
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 approach enables the acquisition of images with high SNR, spatial resolution, contrast, and dynamic range across a wide spectral range, without the need for complex structures or precise manufacturing controls.
Implementation Method 1
a pattern arranged on the array of light-detecting elements, wherein the pattern defines a plurality of transparent areas, each transparent area being associated with a corresponding light-detecting element... controlling a size of a transparent area... associated with a light-detecting element being arranged to detect a wavelength for which the light-detecting element has a high spectral response
Implementation Method 2
The array of light-detecting elements may be formed as an array of photodiodes in a complementary metal-oxide-semiconductor (CMOS) device... a spectral response of photodiodes varies with wavelengths
Data Source
Figure 1~2
Figure 3~4a
Figure 4b~5a
AI summary
An imaging sensor comprises: an array (108) of light-detecting elements (110), wherein each light-detecting element (110) in the array (108) of light-detecting elements (110) is arranged in the imaging sensor (106) so as to detect a respective wavelength interval, wherein the respective wavelength interval differs for different light-detecting elements; a pattern (114) arranged on the array (108) of light-detecting elements (110), wherein the pattern (114) defines a plurality of transparent areas (118), each transparent area (118) being associated with a corresponding light-detecting element (110) in the array (108) of light-detecting elements (110), wherein a size of a transparent area (118) among the plurality of transparent areas (118) is dependent of the corresponding light-detecting element (110) with which the transparent area (118) is associated.