HDR Image Sensor with Interleaved Grey Filters for Motion Artifact Reduction
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Solution Overview
Problem
Standard image sensors have a limited dynamic range, leading to information loss when capturing scenes with luminance beyond their range, and existing HDR techniques suffer from artifacts due to moving objects during multiple exposures.
Innovation Solution
A high-dynamic-range (HDR) color image sensor with a silicon substrate and interleaved pixel arrays, featuring a color filter layer and a dynamic-range extending layer with grey filters to attenuate light, allowing for simultaneous capture of both bright and dim areas without artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple exposures are merged to increase dynamic range, then the captured dynamic range is improved, but artifacts are introduced due to moving objects between exposures
Solution Approach 1:
The pixel array is divided into two interleaved subsets: first pixels without grey filters and second pixels with grey filters. This segmentation allows simultaneous capture of different exposure levels within a single frame, eliminating motion artifacts while maintaining extended dynamic range.
Solution Approach 2:
The patent transitions from temporal dimension (multiple exposures over time) to spatial dimension (interleaved pixel arrays in space). By distributing different exposure levels across spatially separated pixels captured simultaneously, the system achieves HDR without the temporal artifacts of moving objects.
2Device complexity
If standard image sensors are used, then device complexity is reduced, but dynamic range is limited
Solution Approach 1:
The pixel array is segmented into two interleaved subsets with different optical characteristics. This segmentation enables extended dynamic range by combining pixels with different light attenuation properties, achieving HDR capability while maintaining a relatively simple monolithic sensor structure.
Solution Approach 2:
The sensor employs a composite structure combining pixels with and without grey filters in an interleaved pattern. This composite approach integrates multiple functional characteristics (high sensitivity and low sensitivity to light) within a single sensor array, achieving extended dynamic range without requiring multiple separate sensors.
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 HDR color image sensor effectively extends the dynamic range, enabling the capture of detailed images with both bright and dim portions of a scene without information loss, improving image quality and reducing artifacts.
Implementation Method 1
a dynamic-range extending layer disposed on the color filter layer and including grey filters disposed above the second plurality of pixels to attenuate light propagating toward the second plurality of pixels
Implementation Method 2
The first color filters are configured to selectively transmit light of a first color range. The second color filters are configured to selectively transmit light of a second color range
Data Source
AI summary
A method for manufacturing a high-dynamic-range color image sensor includes (a) depositing a color filter layer on a silicon substrate having a photosensitive pixel array with a plurality of first pixels and a plurality of second pixels, to form (i) a plurality of first color filters above a first subset of each of the plurality of first pixels and the plurality of second pixels and (ii) a plurality of second color filters above a second subset of each of the plurality of first pixels and the plurality of second pixels, wherein thickness of the second color filters exceeds thickness of the first color filters, and (b) depositing, on the color filter layer, a dynamic-range extending layer including grey filters above the second pixels to attenuate light propagating toward the second pixels, combined thickness of the color filter layer and the dynamic-range extending layer being uniform across the photosensitive pixel array.