Image Sensor Color Filter Layout for Balanced Sensitivity
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Solution Overview
Problem
Conventional imaging systems using color filters with red, green, and blue filters suffer from inadequate image quality due to differences in signal output levels from light beams passing through clear or yellow filters, which affect sensitivity.
Innovation Solution
A novel image sensor with multiple photoelectric conversion elements and individual color filters, including primary color filters that transmit light of corresponding and other primary colors with a higher transmittance than conventional filters, is used to generate color images by processing signals from these elements with different correction coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional color filters (red, green, blue) are used in imaging systems, then the system can capture color information, but the signal output levels from light beams passing through clear or yellow filters differ significantly, reducing sensitivity and image quality
Solution Approach 1:
The patent applies parameter changes by modifying the transmittance characteristics of color filters. Specifically, it uses primary color filters (red, green, blue) with adjusted transmittance parameters to allow each filter to transmit its corresponding primary color light with high transmittance (above lower limit) while maintaining controlled transmittance for other primary colors. This parameter adjustment resolves the signal level inconsistency problem while preserving sensitivity.
2Reliability
If clear or yellow filters are used instead of green filters to enhance sensitivity, then sensitivity improves, but the signal output level from pixels entered by light beams passing through these filters becomes different from other pixels, degrading image quality
Solution Approach 1:
The patent resolves this contradiction by changing the transmittance parameters of the green filter to a primary color filter with specific characteristics. The green filter is designed to transmit green light with high transmittance (above lower limit) while transmitting red and blue light with controlled transmittance. This parameter adjustment maintains sensitivity while ensuring signal level consistency across all color channels.
Solution Approach 2:
The patent applies local quality by making each color filter have differentiated transmittance characteristics tailored to its specific function. Each primary color filter (red, green, blue) has a unique transmittance profile optimized for its corresponding wavelength while maintaining appropriate transmittance for other wavelengths. This localized optimization ensures both high sensitivity for the target color and consistent signal levels across all channels.
3Reliability
If primary color filters with high transmittance for corresponding primary colors are used, then sensitivity improves, but the device complexity increases due to multiple individual color filters with different transmittance characteristics
Solution Approach 1:
The patent manages device complexity by systematically defining transmittance parameters for each color filter. Instead of using complex multi-layer filters, it employs primary color filters with clearly specified transmittance characteristics: high transmittance for the corresponding primary color (above lower limit) and controlled transmittance for other primary colors. This standardized parameter approach simplifies the overall filter configuration while maintaining high sensitivity.
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 enhances image sensor sensitivity by reducing signal level differences across photoelectric conversion elements, improving image quality even under varying ambient brightness conditions.
Implementation Method 1
multiple photoelectric conversion elements and multiple individual color filters to generate multiple colors
Data Source
AI summary
An image sensor includes multiple photoelectric conversion elements and multiple individual color filters to generate multiple colors. The multiple individual color filters are arranged corresponding to the multiple photoelectric conversion elements, respectively. At least one of the multiple individual color filters includes a primary color type individual color filter. The primary color type individual color filter allows light of a corresponding primary color to permeate. The primary color type individual color filter has a first given transmittance for one of other primary colors other than the corresponding primary color, at which one of the other primary colors permeates the primary color type individual color filter. The first given transmittance is higher than a lower limit of a transmittance improving a sensitivity of the image sensor.