Luminescence Sensor Substrate Optical Redirection
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Solution Overview
Problem
Fluorescence-based optical chemical and biological sensors face low fluorescence collection efficiency due to total internal reflection and low numerical aperture of detection optics, which limits optical detection performance and requires a trade-off between substrate patterning and fluorescence collection enhancement.
Innovation Solution
Incorporating an optical redirection element into the lower surface of the sensor substrate to preferentially transmit and redirect supercritical angle light out of the substrate, allowing for its collection by a detector without affecting the continuous nature of the upper surface, using refractive or reflective elements like paraboloidal, ring lens, Fresnel, or spherical structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical elements are integrated onto the top surface of the substrate to collect supercritical angle fluorescence, then fluorescence collection efficiency is improved, but the continuous nature of the sensor's top surface is affected which is not optimal for patterning sensor sites
Solution Approach 1:
The patent inverts the conventional approach by placing optical redirection elements on the bottom surface of the substrate instead of the top surface. This allows supercritical angle fluorescence to be redirected from below without interfering with the top surface continuity needed for sensor site patterning, thereby resolving the contradiction between improving fluorescence collection efficiency and maintaining ease of patterning operation
Solution Approach 2:
The patent moves the optical element integration from the two-dimensional top surface plane to the bottom surface, utilizing the third dimension (depth/substrate thickness) to separate the optical collection function from the sensor patterning function. This dimensional relocation allows both functions to coexist without interference
2Measurement precision
If the numerical aperture of the detection optics is increased to improve fluorescence collection, then fluorescence collection efficiency is improved, but the complexity and cost of the detection system increases
Solution Approach 1:
The patent extracts the light redirection function from the detection optics and implements it through passive optical elements (Fresnel lenses, microlens arrays) integrated into the substrate itself. This transfers the collection enhancement burden from the complex detection optics to simpler substrate-integrated elements, thereby improving fluorescence collection efficiency while reducing detection system complexity
Solution Approach 2:
The patent introduces intermediary optical elements (Fresnel lenses, microlens arrays) as mediators between the fluorescence emission sites and the detection optics. These intermediaries pre-condition the light paths by redirecting supercritical angle fluorescence, making the subsequent detection process more efficient without requiring high numerical aperture optics
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
Enhances fluorescence collection efficiency by redirecting supercritical angle light out of the substrate for detection, enabling higher optical detection performance while maintaining the substrate's upper surface for sensor site patterning, and allowing for increased sensor site density and cost-effective fabrication.
Implementation Method 1
The preferential transmission of the supercritical angle light may in certain arrangement provide a redirection of the supercritical angle light through a refraction process, the optical redirection element providing a refractive optical element
Implementation Method 2
a significant proportion of the emitted fluorescence being trapped within the substrate by total internal reflection (TIR)
Data Source
AI summary
A sensor comprising a substrate (100) having a first surface (105) and a second surface (110) is described. The first surface has at least one sensor site (115) provided thereon. The substrate is configured such that on excitation of a sample provided at the sensor site, luminescence originating from the sensor site propagates into the substrate, the second surface of the substrate being configured to selectively transmit the luminescence propagating within the substrates at angles greater than the critical angle out of the substrate where it may be detected by a detector (160) provided below the substrate.