Fabry-Pérot Light Sensor Stack for Damage-Free Spectral Detection
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Solution Overview
Problem
Existing light sensors manufactured using thin-film technology face damage to photo-sensitive elements due to the formation of Fabry-Pérot filters, which is a challenge in acquiring spectral information without harming these elements.
Innovation Solution
A light sensor design with an upper and lower reflective element, a photo-sensitive element, and a spacer element forming a resonance structure, where the spacer element is arranged between the reflective elements, allowing for different materials distribution to control resonance wavelengths without affecting the photo-sensitive element during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Fabry-Pérot filters are formed on photo-sensitive elements using thin-film technology, then spectral information can be acquired, but the photo-sensitive elements are damaged or harmed during manufacturing
Solution Approach 1:
The patent inverts the conventional manufacturing sequence by forming the spacer element and lower reflective element before depositing the photo-sensitive element. This reversal prevents the photo-sensitive element from being exposed to damaging high-energy particle beams during subsequent thin-film deposition processes, while still enabling Fabry-Pérot filter formation for spectral detection.
Solution Approach 2:
The spacer element is formed in advance before the photo-sensitive element is deposited. This preliminary action establishes the structural framework and optical cavity spacing needed for Fabry-Pérot filter operation, allowing the photo-sensitive element to be deposited afterward without undergoing damaging manufacturing processes.
2Measurement precision
If the spacer element uses at least two different materials with different distributions for different pixels, then resonance wavelengths can be controlled for spectral resolution, but the manufacturing process becomes more complex
Solution Approach 1:
The spacer element incorporates at least two different materials with spatially varying distributions tailored to specific pixel requirements. This local differentiation enables precise control of resonance wavelengths for different spectral bands while maintaining a relatively simple overall structure that can be manufactured using standard thin-film deposition techniques.
Solution Approach 2:
The patent controls resonance wavelengths by changing the material composition and distribution within the spacer element. By varying the effective refractive index through different material distributions, the optical path length and resonant conditions are tuned for different pixels without requiring complex geometric structures.
3Adaptability or versatility
If photo-sensitive elements are formed using thin-film technology for extended wavelength ranges, then detection capability is improved, but the elements become more susceptible to damage during subsequent manufacturing steps
Solution Approach 1:
The manufacturing sequence is inverted so that photo-sensitive elements are deposited first when the substrate is most stable, before subsequent high-energy thin-film deposition processes. This protects the photo-sensitive elements from damage while maintaining their extended wavelength detection capabilities enabled by thin-film technology.
Solution Approach 2:
The patent protects photo-sensitive elements by completing their deposition beforehand, before exposing them to potentially damaging manufacturing processes. This timing strategy cushions the fragile photo-sensitive elements from harmful effects while preserving their enhanced spectral detection capabilities.
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
Facilitates the manufacturing of a light sensor that can detect spectral information without damaging the photo-sensitive elements, enabling flexible manufacturing and improved spectral resolution with reduced manufacturing complexity.
Implementation Method 1
the stack of layers define a resonance structure between the upper reflective element and the lower reflective element for providing a resonance of light dependent on a wavelength of the light
Implementation Method 2
Fabry-Pérot filters may be used for defining wavelength bands of the pixels. A Fabry-Pérot filter uses two reflective surfaces which are spaced apart such that constructive interference of light having traveled different number of times between the reflective surfaces may be formed
Implementation Method 3
By changing an effective refractive index of a material between the two reflective surfaces, a resonant wavelength of the Fabry-Perot filter is changed
Implementation Method 4
A light sensor may thus comprise photo-sensitive element(s) forming an array of pixels, wherein different pixels may be configured to detect different wavelength bands in order to acquire spectral information
Data Source
AI summary
A light sensor for spectrally resolved light detection, said light sensor comprises: an upper reflective element; a lower reflective element; a photo-sensitive element therebetween; a spacer element, configured to form the lower reflective element or arranged between the upper and the lower reflective element; wherein the elements form a stack of layers which define a resonance structure between the upper and the lower reflective element for providing a resonance of light; wherein the spacer element comprises at least two different materials, a distribution of which is different between different pixels in an array of pixels such that a resonance wavelength is different for different pixels; and wherein for a plurality of pixels, geometrical structures smaller than the resonance wavelength are defined by the at least two different materials.