Optical Conjugation for Plasmonic Detection Stability
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Solution Overview
Problem
Existing detection devices face challenges in maintaining accurate detection of substances due to changes in environment, such as temperature fluctuations, which can cause deviations in the emission direction of light from the light projecting unit, leading to incorrect irradiation positions on the metal film and reduced detection accuracy.
Innovation Solution
A detection device is designed with a light projecting unit that includes a light source, a diaphragm for regulating light flux, and a conjugate optical system to optically conjugate the diaphragm opening and the region on the metal film irradiated with excitation light, ensuring accurate positioning and robustness against temperature and temporal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a light source (laser diode, LED, etc.) is used to generate excitation light, then the detection device can perform surface plasmon resonance measurement, but temperature rise around the light source causes linear expansion and eccentricity, leading to deviation in light emission direction and irradiation position on the metal film
Solution Approach 1:
The patent applies preliminary action by pre-positioning the light source at the optical center of the prism before temperature rise occurs. The light source is initially aligned with the optical center, and the system is designed to maintain this alignment despite subsequent thermal expansion. This preliminary positioning ensures that even when temperature increases cause linear expansion, the light source remains centered relative to the optical path, preventing deviation in light emission direction and maintaining accurate irradiation position on the metal film.
Solution Approach 2:
The patent implements equipotentiality by ensuring the light source is positioned at the optical center of the prism, creating a symmetric optical configuration. This central positioning creates an equipotential point in the optical system where thermal expansion affects all directions equally, thereby maintaining the light source's alignment with the optical axis despite temperature changes. This symmetric arrangement prevents eccentricity from causing directional deviation in light emission.
2Adaptability or versatility
If angle scanning is performed to detect optimum angle for surface plasmon resonance, then enhancement angle measurement can be achieved, but deviation of irradiation position is increased for each angle, causing measurement performance deterioration
Solution Approach 1:
The patent applies preliminary action by pre-aligning the light source with the optical center of the prism before angle scanning begins. This initial precise positioning ensures that the light beam passes through the correct path at each scanning angle. By establishing the correct geometric relationship between the light source, prism optical center, and metal film irradiation region beforehand, the system maintains measurement accuracy throughout the angle scanning process, preventing irradiation position deviation from increasing with each angle change.
3Device complexity
If the light source position is not precisely controlled, then the device structure can be simpler, but the irradiation position on the metal film deviates, preventing accurate detection of the substance
Solution Approach 1:
The patent applies preliminary action by establishing the light source position at the optical center of the prism as a fixed, pre-determined configuration. This preliminary positioning eliminates the need for complex real-time adjustment mechanisms during operation. By setting the light source at the optimal position before measurement begins and maintaining this position through proper mechanical design, the system achieves accurate substance detection without requiring overly complex positioning systems.
Solution Approach 2:
The patent implements self-service through the self-aligning property of positioning the light source at the optical center of the prism. This central position serves as a natural reference point that automatically maintains proper alignment through the optical system. The geometric symmetry of the prism's optical center provides inherent alignment guidance, allowing the light source to maintain correct positioning without requiring complex external alignment mechanisms or continuous active control.
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 detection device achieves high robustness against temperature and temporal changes, ensuring accurate detection of substances by maintaining precise irradiation positions on the metal film, thereby improving measurement accuracy and reliability.
Implementation Method 1
a light projecting unit configured to irradiate the metal film of the detection chip held by the chip holder with excitation light to generate the surface plasmon resonance
Implementation Method 2
a conjugate optical system that optically conjugates an opening portion of the diaphragm and a region of the metal film irradiated with the excitation light
Implementation Method 3
a detection unit configured to detect light that is derived from the presence or the amount of the substance to be detected, and is generated by occurrence of the surface plasmon resonance
Data Source
AI summary
The present invention relates to providing a detection device that has high robustness against a temperature change and a temporal change and that is capable of detecting a substance to be detected with high accuracy. The detection device of the present invention is a detection device that detects presence or an amount of a substance to be detected using an enhanced electric field based on surface plasmon resonance, the detection device having a light projecting unit for irradiating a metal film of a detection chip held by a chip holder with excitation light via a prism. The light projecting unit includes: a light source; a diaphragm for regulating an amount of light from the light source; and a conjugate optical system that optically conjugates an opening portion of the diaphragm and a region of the metal film irradiated with the excitation light.