Chemical Sensor Waveguide Crosstalk Reduction
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Solution Overview
Problem
Existing biomolecule detection methods face challenges in sensitivity and accuracy due to inadequate light guidance and crosstalk issues, as well as material limitations that degrade light transmittance and sensitivity, particularly in structures without defined surface binding for organic molecule probes.
Innovation Solution
A chemical sensor with a substrate, optical layer, and intermediate layer, featuring waveguides that guide fluorescence to photodiodes, a reflection surface for angle-independent detection, and a spectral filter to attenuate excitation light, ensuring high accuracy and preventing crosstalk by using a tapered waveguide and color filters for multidirectional analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If isotropic light is emitted from the organic molecule probe without an optical guidance system, then the structure is simple, but the light quantity reaching the detector is insufficient and sensitivity is low
Solution Approach 1:
A micro lens is introduced as an intermediary optical element between the probe and the solid state image pickup element. The micro lens collects isotropic fluorescence light and focuses it onto the photodetector, significantly improving light collection efficiency and detection sensitivity without requiring a complex optical system
Solution Approach 2:
The patent transitions from planar probe arrangement to three-dimensional integration by positioning the micro lens above the probe area and the solid state image pickup element below, creating a vertical optical path that efficiently guides fluorescence light from the isotropic emission to the detector
2Measurement precision
If no optical guidance system is provided, then the device structure is simple, but crosstalk between adjacent detection elements occurs
Solution Approach 1:
The micro lens acts as an optical intermediary that confines and directs light paths. By focusing fluorescence light from specific probe areas onto corresponding photodetector elements, it prevents light from spreading to adjacent detectors, thereby eliminating crosstalk without requiring complex isolation structures
Solution Approach 2:
The detection system is segmented into discrete probe areas, each with its own micro lens and corresponding photodetector element. This segmentation creates independent detection channels that prevent optical interference between adjacent measurement zones
3Ease of operation
If a light transmissive top gate electrode is formed on the micro lens, then electrical control is enabled, but light transmittance is degraded and sensitivity is reduced
Solution Approach 1:
The patent extracts the gate electrode function from the optical path by forming the gate electrode on the side surface of the micro lens rather than on its top surface. This allows electrical control of the micro lens while preserving its light transmittance properties, as the gate electrode no longer blocks the optical path
Solution Approach 2:
The gate electrode is repositioned from the top surface (blocking the optical path) to the side surface of the micro lens. This spatial relocation enables simultaneous achievement of electrical control functionality and optimal light transmittance for fluorescence detection
4Measurement precision
If the organic molecule probe binding surface material is not defined, then material selection is flexible, but detection accuracy cannot be improved through uniform probe binding
Solution Approach 1:
The patent applies different surface treatments to different regions of the substrate: the probe binding area receives a specific surface treatment (such as oxygen plasma treatment or coating with binding-promoting material) to ensure uniform probe attachment, while other areas maintain their original properties. This localized quality enhancement improves detection accuracy without requiring complex treatment of the entire device
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 high-accuracy detection of biomolecules by effectively guiding and isolating fluorescence, improving signal-to-noise ratio and preventing crosstalk, thus enhancing the sensitivity and precision of biomolecule detection.
Implementation Method 1
The optical layer has a waveguide which guides fluorescence to a photodiode
Implementation Method 2
The waveguide has a spectral filter formed therein which attenuates excitation light
Implementation Method 3
The waveguide may be surrounded by a reflection surface having light reflectiveness
Implementation Method 4
fluorescence to a photodiode... fluorescence generated by binding a target material to an organic molecule probe disposed in the organic molecule probe disposition area is detected by the solid state image pickup element
Data Source
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AI summary
[Object] To provide a chemical sensor, a biomolecule detection apparatus, and a biomolecule detection method capable of detecting a biomolecule with high accuracy. [Solving Means] A chemical sensor according to the present invention includes a substrate, an optical layer, and an intermediate layer. On the substrate, a plurality of photodiodes is arranged in a planar form. The optical layer is laminated on the substrate and has a waveguide formed therein which guides incident light to each of the photodiodes. The intermediate layer is laminated on the optical layer and has a probe holding area formed thereon for each waveguide, and the probe holding area is capable of holding a probe material.