Array Camera Spectral Filter Placement to Reduce Crosstalk
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Solution Overview
Problem
Array cameras face crosstalk phenomena due to light leakage between optical channels, degrading camera performance, which is exacerbated by the inclusion of spectral filters within the image sensor, increasing pixel stack height and complexity in manufacturing lenses with embedded filters.
Innovation Solution
Spectral filters are disposed outside of the constituent image sensor, either within or proximate to a glass substrate, reducing pixel stack height and allowing for various fabrication techniques, including polymer injection molding and precision glass molding, while maintaining effective spectral filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spectral filters are included within the image sensor, then spectral filtering capability is improved, but pixel stack height increases and manufacturing complexity increases
Solution Approach 1:
The spectral filter is extracted from the image sensor and relocated to a separate optical element (lens or cover glass) in the optical path. This extraction resolves the contradiction by maintaining spectral filtering capability while reducing pixel stack height and simplifying manufacturing, as the filter is no longer integrated within the sensor structure.
2Reliability
If spectral filters are embedded within lenses, then spectral filtering is achieved, but manufacturing complexity increases
Solution Approach 1:
The spectral filter is extracted from the lens structure and placed as a separate element (such as a filter layer on cover glass or a standalone optical element). This allows the lens to be manufactured using conventional molding techniques without the complexity of integrating embedded filters, while spectral filtering remains effective.
3Reliability
If array cameras use multiple focal planes with separate lens stacks, then imaging capability is improved, but crosstalk between optical channels increases
Solution Approach 1:
A spectral filter is introduced as an intermediary element in the optical path to selectively block stray light from reaching adjacent focal planes. This mediator prevents crosstalk between optical channels while maintaining the multi-focal-plane imaging capability, as the filter selectively transmits desired wavelengths to the correct focal plane.
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 configuration reduces crosstalk and allows for diverse manufacturing methods, enhancing image quality and camera performance by minimizing light leakage and simplifying lens fabrication.
Implementation Method 1
at least one spectral filter disposed within, or else proximate to, at least one glass substrate within the lens stack array
Data Source
AI summary
Systems and methods in accordance with embodiments of the invention implement array cameras and array camera modules that have spectral filters disposed outside of constituent image sensors. In one embodiment, an array camera module includes: a lens stack array including lens elements arranged to form a plurality of optical channels, each optical channel including a field-of-view that is shifted with respect to the fields-of-views of each other optical channel so that each shift includes a sub-pixel shifted view of the scene, a glass substrate located within an optical channel, and a spectral filter disposed within, or else proximate to, a glass substrate within the lens stack array; and an imager array including a plurality of focal planes, where each focal plane includes a plurality of rows of pixels that also form a plurality of columns of pixels, and where each focal plane does not include pixels from another focal plane.