Alternating Row Infrared Filter for Image Sensor
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Solution Overview
Problem
Conventional image sensors struggle to capture quality images in normal and low light conditions due to the interference of infrared and near-infrared light, which affects their performance and output levels.
Innovation Solution
The implementation of near-infrared cut filters formed in a predetermined pattern over an array of photosensitive elements, allowing visible light to pass while filtering out near-infrared light, enabling improved sensitivity in low light conditions and accurate color capture in normal light conditions by selectively activating or deactivating filter regions of split pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared and/or near infrared blocking filter is used, then image quality in normal light conditions is improved, but sensitivity in low light conditions deteriorates
Solution Approach 1:
The image sensor array is divided into two distinct groups: first image sensor elements with infrared blocking filters for color imaging in normal light, and second image sensor elements without filters for sensitive detection in low light. This segmentation allows each subset to be optimized for its specific function, resolving the contradiction between color accuracy and sensitivity.
Solution Approach 2:
Different regions of the image sensor array have different optical properties - some pixels have infrared blocking filters while others don't. This local differentiation enables the system to simultaneously achieve both color accuracy (where filters are present) and sensitivity (where filters are absent), rather than requiring a uniform design that compromises one or the other.
2Reliability
If no infrared blocking filter is used, then sensitivity in low light conditions is improved, but color accuracy in normal light conditions deteriorates
Solution Approach 1:
The array is segmented into filter-equipped pixels for color imaging and filter-less pixels for sensitive imaging. By processing data from both subsets appropriately, the system achieves both color accuracy from the filtered pixels and sensitivity from the unfiltered pixels, eliminating the need to choose one over the other.
Solution Approach 2:
The patent combines the outputs of two different pixel types - those with infrared blocking filters and those without - into a single image. This merging allows the final image to benefit from both color accuracy (from filtered pixels) and sensitivity (from unfiltered pixels), resolving the contradiction between these two requirements.
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 solution enhances image sensor performance by allowing it to be sensitive in low light conditions while maintaining color accuracy in normal light, reducing blooming and improving image quality through selective filtering and exposure control.
Implementation Method 1
near-infrared cut filters formed in a predetermined pattern over an array of photosensitive elements... allowing visible light to pass while filtering out near-infrared light
Implementation Method 2
an image sensor having near-infrared cut filters formed over a portion of an array of photosensitive elements
Data Source
AI summary
An image sensor includes near-infrared cut filters formed over an array of photosensitive elements in a predetermined pattern. The near-infrared cut filters may be formed over one half of a photosensitive element in a split pixel arrangement, over one half the photosensitive elements in the array, over every other photosensitive element in the array, and/or in a checkerboard pattern.