Curved Imaging Sensor Substrate for Tight-Radius Stress Relief
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Solution Overview
Problem
Curved imaging sensors face challenges in being curved to tighter radii of curvature without breaking or experiencing imaging degradation due to strain and stress concentrations, which are exacerbated by non-linear strain when spherically curving flat imaging sensors.
Innovation Solution
An architected substrate with low-amplitude wrinkling is coupled to the imaging sensor, reducing strain energy and stress concentrations by adjusting the stress distribution, allowing for curvature without degrading imaging performance, even in large-format sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a flat imaging sensor is curved to a tighter radius of curvature, then the imaging system size is reduced and operational window is extended, but the strain and stress concentrations increase causing breakage and imaging degradation
Solution Approach 1:
The patent applies parameter changes by modifying the physical and mechanical properties of the substrate through architectural design. The substrate transitions from a uniform flat structure to an architected structure with varying stiffness parameters, allowing it to accommodate curvature while managing stress distribution. This enables the sensor to be curved to tighter radii without breaking by changing the substrate's mechanical response characteristics.
Solution Approach 2:
The patent employs composite material principles by creating an architected substrate that combines regions of different stiffness. This heterogeneous structure allows the substrate to flex and curve while maintaining structural integrity in critical areas. The composite architecture enables the sensor to withstand the stresses of tight curvature without degradation.
2Device complexity
If a flat imaging sensor is spherically curved, then curved focal plane is achieved eliminating need for complex optics, but non-linear strain causes output shift and imaging degradation
Solution Approach 1:
The patent applies local quality by creating regions of different stiffness within the substrate architecture. These localized stiffness variations are strategically positioned to counteract the non-linear strain distribution that occurs during spherical curving. By making different parts of the substrate have different mechanical properties, the patent compensates for strain-induced output shifts and maintains imaging uniformity across the curved focal plane.
3Productivity
If the imaging sensor is curved to tighter radius, then frame rate and operational window are enhanced, but stress concentrations cause breakage and performance degradation
Solution Approach 1:
The patent applies beforehand cushioning by designing the architected substrate to preemptively manage stress concentrations before they can cause damage. The substrate's architectural features are positioned in advance to absorb and distribute stresses that will arise during tight curving, preventing breakage and performance degradation before they occur. This proactive stress management enables reliable operation at enhanced frame rates.
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 enables imaging sensors to be curved to tighter radii without breakage or performance degradation, maintaining uniform illumination and reducing stress concentrations, thus enhancing the operational window and frame rate of imaging devices.
Implementation Method 1
the architected substrate imparts a low-amplitude wrinkling phenomenon onto the imaging sensor that reduces deleterious strain while allowing the imaging sensor (e.g., the FPA) to remain near the spherical focal surface for accurate imaging
Implementation Method 2
the total strain energy in the imaging sensor may be reduced by alleviating the compressive strain therein through the low-amplitude wrinkling that occurs during the curving
Data Source
AI summary
An imaging sensor package includes: an imaging sensor; and an architected substrate coupled to a bottom surface of the imaging sensor. The architected substrate has local stiffness variations along an in-plane direction of the architected substrate, and the imaging sensor and the architected substrate are curved.