Image Sensor Near-Infrared Visible Light Pixel Array
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Solution Overview
Problem
Conventional image sensors require impractical physically moveable IR filters to achieve both visible light and near-infrared sensitivity, necessitating a cost-effective solution for simultaneous visible and near-infrared light sensitivity.
Innovation Solution
The implementation of image sensors with specific color filter patterns and pixel layouts that integrate both visible light and near-infrared sensitivity, allowing for custom-free processing and efficient signal processing to combine visible and near-infrared light information into a single output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a physically moveable IR filter is used to obtain near-infrared and visible light sensitivity, then both spectral ranges can be captured, but the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The pixel array is segmented into distinct near-infrared pixel groups and visible light pixel groups with different color filter patterns. NIR pixels use a first color filter pattern optimized for near-infrared transmission, while visible light pixels use a second color filter pattern optimized for visible spectrum transmission. This segmentation allows each pixel type to be optimized for its specific spectral range without requiring complex moveable filters.
Solution Approach 2:
Instead of using a moveable filter in the optical path (spatial dimension), the patent transitions to a fixed pixel-level filtering approach where different color filter patterns are assigned to different pixel groups in the array. This dimensional change from optical path filtering to sensor array patterning eliminates the need for mechanical filter components.
2Measurement precision
If custom pattern processing is implemented to handle mixed pixel outputs, then accurate image reconstruction is achieved, but processing complexity and computational requirements increase
Solution Approach 1:
The color filter patterns are pre-configured in a specific repeating 2×2 unit cell arrangement during sensor manufacturing. This preliminary arrangement of filters ensures that the raw pixel outputs follow a predictable, regular pattern that can be easily decoded by standard processing circuitry, eliminating the need for complex custom processing algorithms.
Solution Approach 2:
The patent uses a repeating unit cell pattern throughout the pixel array, creating homogeneity in the filter distribution. This uniform repeating pattern allows standard image processing algorithms to efficiently handle the data without requiring pixel-specific or region-specific processing logic, thereby reducing overall processing complexity.
3Adaptability or versatility
If separate color filter patterns are used for NIR and visible light pixels, then spectral selectivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs asymmetric color filter patterns within the 2×2 unit cell structure, where specific positions are assigned to NIR-optimized filters and visible light-optimized filters. This asymmetric but regular arrangement provides clear spectral selectivity while maintaining a simple repeating pattern that is tolerant to manufacturing variations.
Solution Approach 2:
The color filter structures serve dual purposes: they provide spectral filtering for their designated wavelength ranges while simultaneously forming a regular repeating pattern that simplifies manufacturing. The same basic filter structure is repeated throughout the array with only positional variations, allowing standardized fabrication processes to achieve both spectral selectivity and pattern accuracy.
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 image sensors to capture both visible and near-infrared light without the need for custom pattern processing, maintaining performance in various lighting conditions while minimizing additional processing requirements and costs.
Implementation Method 1
The image pixels contain a photodiode for generating charge in response to light
Data Source
AI summary
An image sensor may include an array of imaging pixels and an array of color filter elements that covers the array of imaging pixels. The array of imaging pixels may include visible light pixels that are covered by visible light color filter elements and near-infrared light pixels that are covered by near-infrared light color filter elements. The imaging pixels may be arranged in a pattern having a repeating 2×2 unit cell of pixel groups. Each pixel group may include a visible light pixel sub-group and a near-infrared light pixel sub-group. Signals from each pixel group may be processed to determine a representative value for each pixel group that includes both visible light and near-infrared light information.