Microchip Channel Refractive Index Alignment for Laser Fluorescence
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Solution Overview
Problem
The side-entry method for laser-induced fluorescence detection in microchips is challenging due to difficulties in aligning lenses between channels, leading to reduced sensitivity and increased manufacturing costs, as well as limitations in channel density and disposability.
Innovation Solution
A microchip design with alternating channels of different refractive indices, where one channel acts as a concave lens and the other as a convex lens, allowing efficient laser beam propagation and alignment without the need for external lenses, enabling high sensitivity fluorescence detection and easy manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If external lenses are inserted between channels for laser beam alignment, then laser beam alignment precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The microchip channels themselves serve as the optical alignment elements. By designing channels with specific refractive indices and geometric configurations (e.g., trapezoidal cross-sections), the channels automatically guide and align the laser beam through refraction without requiring external lenses. This self-aligning mechanism eliminates complex lens insertion and positioning procedures.
Solution Approach 2:
The invention changes the refractive index parameter of the channel materials to achieve beam alignment. Channels are filled with materials having different refractive indices (e.g., n2 > n1 for concave lens effect, n3 > n2 for convex lens effect) to create optical path differences that naturally guide the laser beam through the channels in a linear array configuration.
2Measurement precision
If external lenses are used for laser beam alignment, then fluorescence detection sensitivity is improved, but manufacturing cost increases
Solution Approach 1:
The channels perform dual functions: sample transport and optical beam guidance. The same structural elements (channels) that carry the sample also serve as the optical alignment system through their refractive index properties, eliminating the need for separate lens components and reducing manufacturing steps.
Solution Approach 2:
By adjusting the refractive index parameters of channel materials and their geometric configurations, the system achieves optimal beam focusing and fluorescence detection sensitivity without requiring expensive precision lenses, thereby reducing overall manufacturing cost.
3Productivity
If laser beam is expanded to span multiple channels, then measurement throughput is improved, but laser beam strength density decreases
Solution Approach 1:
The laser beam is divided into multiple segments, with each segment directed into a specific channel through the refraction effects created by the alternating refractive index channels. This segmentation allows simultaneous irradiation of multiple channels while maintaining adequate beam strength density in each channel for sensitive fluorescence detection.
Solution Approach 2:
The invention uses the vertical dimension (depth) of the channel structure to achieve beam distribution. By creating refraction patterns through alternating refractive index channels, the system distributes the laser beam across multiple channels in the lateral dimension while maintaining beam intensity through the vertical refraction path.
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 design achieves high sensitivity fluorescence detection across multiple channels with a simple configuration, low manufacturing costs, and maintains channel density, while ensuring the microchip's disposability.
Implementation Method 1
a first channel filled with a first material having a refractive index n2 and a second channel filled with a second material having a refractive index n3 are mixed in the plurality of channels, and a relation of n213 is satisfied
Implementation Method 2
one channel acts as a concave lens and the other as a convex lens
Implementation Method 3
laser-induced fluorescence detection of a fluorescent analyte existing in a plurality of channels
Data Source
AI summary
Efficient simultaneous laser-irradiation-fluorescence detection is performed for a plurality of channels of a microchip and simple and highly sensitive parallel analysis of a plurality of samples is enabled. In a microchip 1 made of an optically transparent solid material m1 with a refractive index n1, a plurality of channels 2 filled with a material m2 with a refractive index n2 and a plurality of channels 3 filled with a material m3 with a refractive index n3 are alternately arranged in parallel on the same plane. Here, m1, m2 and m3 are selected such that a relation of n2<n1<n3 is satisfied. The material m2 is an optically transparent liquid suitable for targeted analysis. When a laser beam 4 is focused and irradiated perpendicularly to the individual channels 2 and 3 along the same plane, refraction of the laser beam 4 by the channels 2 and refraction of the laser beam 4 by the channels 3 are counterbalanced. For this reason, the laser beam 4 propagates linearly on the same plane and the individual channels 2 and 3 can be simultaneously and efficiently irradiated with the laser beam. Fluorescence emitted from the individual channels 2 and 3 is detected independently and simultaneously using a collimating lens 9, a filter and a diffraction grating 10, an imaging lens 11, a two-dimensional sensor 12, and a data analysis system 13, from a direction perpendicular to the same plane.