Focal Plane Array Light Shielding for Stray Light Suppression
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Solution Overview
Problem
Imaging systems face challenges in effectively blocking stray light, which can lead to artifacts, noise, and distortion in captured images.
Innovation Solution
The implementation of a focal plane array with a light shield or alignment frame that couples to the focal plane array, aligns optical elements, and blocks stray light by absorption or scattering, ensuring that only desired electromagnetic radiation reaches the detector array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light shield is added to block stray light, then image quality improves, but device complexity increases
Solution Approach 1:
The light shield is integrated within the focal plane array structure itself, with light-blocking features formed as part of the substrate or overlay layers. This nesting approach allows the light shield to be incorporated without adding separate external components, thereby blocking stray light while minimizing increases in device complexity.
Solution Approach 2:
The light-shielding function is merged with the focal plane array structure by forming light-blocking features using the same substrate material or overlay layers that make up the detector array. This combining of functions allows stray light blocking to be achieved without requiring separate light shield components.
2Measurement precision
If optical elements are added for filtering electromagnetic radiation, then detection precision improves, but alignment precision requirements increase
Solution Approach 1:
Alignment features are pre-formed during the fabrication process of the focal plane array, creating reference structures that guide the positioning of optical elements. This preliminary action establishes alignment references before the optical elements are attached, reducing the need for complex post-assembly alignment procedures.
Solution Approach 2:
Alignment features act as intermediary structures between the substrate and optical elements, providing a standardized interface that simplifies positioning. These features serve as mediators that translate fabrication tolerances into precise optical alignments, reducing the direct alignment precision requirements.
3Reliability
If the focal plane array substrate is made transmissive for desired wavelengths, then detection capability improves, but stray light blocking becomes more difficult
Solution Approach 1:
The substrate exhibits different optical properties in different regions: it is transmissive in areas where detection is needed and opaque or light-blocking in areas where stray light must be prevented. This spatial variation in optical quality allows the substrate to simultaneously enable detection capability while preventing stray light penetration through localized light-blocking features.
Solution Approach 2:
The substrate's transmissivity, which initially allows stray light to penetrate and cause harm, is converted into a benefit by using the same substrate material to create light-blocking features. The substrate's ability to be patterned with both transmissive and blocking regions transforms the potential harm of transmissivity into the benefit of selective wavelength filtering.
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 significantly reduces stray light interference, improving image quality by minimizing artifacts and noise, and allowing for precise alignment of optical elements with the detector array.
Implementation Method 1
The light shield is coupled to the FPA and configured to block a second portion of the electromagnetic radiation
Implementation Method 2
an optical element for filtering the first portion of electromagnetic radiation as the first portion approaches the detector array
Data Source
AI summary
Techniques are disclosed for optical imager devices, systems, and methods. In one example, an imaging system includes a focal plane array (FPA) and a light shield. The FPA includes a detector array configured to detect a first portion of electromagnetic radiation and generate a detector signal based on the first portion. The FPA further includes a readout circuit coupled to the detector array and configured to receive the detector signal. The light shield is coupled to the FPA and configured to block a second portion of the electromagnetic radiation. Related devices and methods are also provided.