Integrated Infrared Optical Filter-Sensor for Stray Light Rejection
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Solution Overview
Problem
Existing optical detectors in the infrared spectral range face challenges in effectively removing stray light while being simple, cost-efficient, and reliable, particularly in applications requiring multiple filters to avoid cross-talk and maintain sensitivity to transmissivity, absorption, emission, and reflectance.
Innovation Solution
The optical detector incorporates an optical filter with a semiconducting substrate, a sensor layer of photoconductive materials, and an interlayer to enhance stray light rejection, using long pass filters and photoconductive materials like PbS, PbSe, and quantum dots, with an evaluation device for signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate filters are used to remove stray light in different spectral ranges, then the effectiveness of stray light removal is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines multiple filter functions (UV, VIS, and NIR stray light removal) into a single integrated optical filter structure. This single filter simultaneously performs spectral selection for infrared detection while blocking stray light across multiple wavelength ranges, thereby maintaining high reliability in stray light removal while reducing device complexity compared to using multiple separate filters
Solution Approach 2:
The optical filter is designed with multi-functional capability to handle multiple spectral ranges (UV, VIS, NIR) and perform both wavelength selection and stray light rejection in a single component. This universal filter replaces what would traditionally require multiple specialized filters, simplifying the overall detector architecture while maintaining comprehensive stray light removal effectiveness
2Device complexity
If an optical filter is integrated directly with the sensor layer, then the device complexity is reduced and cost is lowered, but the effectiveness of stray light removal may be compromised
Solution Approach 1:
The patent merges the optical filter and sensor layer into an integrated structure where the filter is positioned in direct optical contact with the sensor. This integration maintains effective stray light removal by ensuring that filtered light reaches the sensor without additional interfaces that could cause reflections or scattering, while simultaneously reducing device complexity by eliminating separate filter assemblies and mounting mechanisms
Solution Approach 2:
The integration approach transitions from a multi-component assembly to a planar, layered structure where the optical filter and sensor layer are combined in a two-dimensional configuration. This dimensional simplification reduces the third-dimensional complexity of the detector while preserving the optical filtering functionality through direct layer stacking
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 provides a cost-effective and reliable detector capable of effectively filtering stray light, maintaining sensitivity to infrared radiation, and generating accurate sensor signals for transmissivity, absorption, emission, and reflectance measurements.
Implementation Method 1
the optical filter is designed for allowing an incident light beam received by the first surface to pass through the optical filter to the second surface, thereby generating a modified light beam by modifying a spectral composition of the incident light beam
Implementation Method 2
the sensor layer comprises a photosensitive material being deposited on the second surface of the optical filter, wherein the sensor layer is designed to generate at least one sensor signal in a manner dependent on an illumination of the sensor layer by the modified light beam
Data Source
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AI summary
The invention relates to an optical detector (110) for an optical detection, in particular, of radiation within the infrared spectral range, specifically, with regard to sensing at least one optically conceivable property of an object (112). More particular, the optical detector (110) may be used for determining transmissivity, absorption, emission, reflectance, and/or a position of at least one object (112). Further, the invention relates to a method for manufacturing the optical detector (110) and to various uses of the optical detector (110). The optical detector (110) comprises - an optical filter (114) having at least a first surface (116) and a second surface (118), the second surface (118) being located oppositely with respect to the first surface (116), wherein the optical filter (114) is designed for allowing an incident light beam (120) received by the first surface (116) to pass through the optical filter (114) to the second surface (118), thereby generating a modified light beam (122) by modifying a spectral composition of the incident light beam (120); - a sensor layer (128) comprising a photosensitive material (130) being deposited on the second surface (118) of the optical filter (114), wherein the sensor layer (128) is designed to generate at least one sensor signal in a manner dependent on an illumination of the sensor layer (128) by the modified light beam (122); and - an evaluation device (140) designed to generate at least one item of information provided by the incident light beam (120) by evaluating the sensor signal. The optical detector (110) constitutes an improved simple, cost-efficient and, still, reliable detector for detecting optical radiation, especially within the infrared spectral range, specifically with regard to sensing at least one of transmissivity, absorption, emission and reflectance. Hereby, the optical detector (110) is capable of effectively removing stray light as far as possible.