Segmented Color Filter Array for CMOS Image Sensor Sensitivity
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Solution Overview
Problem
As the number of effective pixels in CMOS image sensors increases, the size of the image sensor does not proportionally increase, leading to reduced light reaching each pixel, which undermines image sensitivity while also limiting color reproducibility.
Innovation Solution
An image photographing device and method that includes a filter unit with complementary and primary color filters, a white filter, and an infrared filter to selectively pass and limit light wavelengths, allowing the image sensor to combine filtered results and calculate color components, thereby enhancing sensitivity without compromising color reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of effective pixels is increased to achieve higher resolution, then the resolution is improved, but the amount of light reaching each pixel is reduced, which undermines sensitivity
Solution Approach 1:
The filter array is segmented into multiple filter types (complementary color filters and primary color filters) arranged in a specific pattern. This segmentation allows different pixel groups to receive different filtered light information, enabling the system to maintain high resolution while improving light utilization efficiency through the combined processing of multiple filter responses.
2Measurement precision
If primary color filters (RGB) are used to enhance color reproducibility, then color reproducibility is improved, but sensitivity is limited because only 1/3 of total light is passed through
Solution Approach 1:
The patent merges the functionality of complementary color filters and primary color filters into a single filter array structure. By combining the light-passing advantage of complementary color filters with the color-selective advantage of primary color filters, the system achieves both improved sensitivity and maintained color reproducibility through integrated multi-filter processing.
Solution Approach 2:
The patent adds a new dimension to traditional color filtering by incorporating both complementary color and primary color filter responses. Instead of relying solely on the traditional RGB primary color filtering approach, the system utilizes an additional filtering dimension that captures more light information while preserving color accuracy through mathematical processing of multiple filter responses.
3Illumination intensity
If complementary color filters are used to improve sensitivity by passing 2/3 of light, then sensitivity is improved, but color reproducibility is reduced
Solution Approach 1:
Different regions of the filter array have different filter qualities - some regions use complementary color filters optimized for light transmission, while other regions use primary color filters optimized for color selection. This local differentiation allows the system to optimize for both sensitivity and color reproducibility in different spatial locations, with the final image reconstructed through processing of these locally optimized responses.
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
The solution effectively increases the amount of light reaching each pixel, enhancing image sensitivity while maintaining color reproducibility, even with increased pixel density without a corresponding increase in image sensor size.
Implementation Method 1
a filter unit including a first filter region to selectively pass through a complementary color of a predetermined color from the incident light, a second filter region to limit the incident light to a predetermined visually observable color light, a third filter region which passes the incident light in wavelength ranges at least beyond the visually observable color light, and a fourth filter region to limit the incident light in an infrared wavelength range
Implementation Method 2
the image sensor detects the light collected by the lens and converts the detected light into an electrical image signal
Data Source
AI summary
An image photographing device and method, with the image photographing device enhancing image sensitivity. The image photographing device may include a lens unit, a filter unit including a first filter region which filters a complementary color of a predetermined color from light incident through the lens unit, a second filter region limiting the incident light to a predetermined primary color, a third filter region which passes all wavelength bands of the incident light, and a fourth filter region which filters outs an infrared wavelength band of the incident light, and an image sensor unit detecting light that passed through the filter unit and sensing an image.