Prism Geometry for Surface Plasmon Resonance Measurement Accuracy
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Solution Overview
Problem
Surface plasmon resonance measuring apparatuses face issues with returning light entering the light source, leading to destabilization of light emission and measurement errors due to total reflection and scattering of the excitation light beam at the prism's output surface, which complicates adjustments and reduces measurement accuracy.
Innovation Solution
The optical member is designed with a light output surface angle and length configuration that prevents the excitation light beam from being irradiated onto the corners of the prism, ensuring it is not totally reflected at the light output surface, thereby eliminating returning light and stabilizing light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light shielding plate is provided to prevent returning light from entering the light source, then returning light is blocked, but the excitation light beam is also shielded
Solution Approach 1:
The patent extracts the harmful returning light from the optical path by carefully designing the prism geometry and light output surface angle to prevent total reflection at the output surface, thereby eliminating the need for a light shielding plate that would block the excitation beam
2Stability of the object's composition
If the excitation light beam is totally reflected at the light output surface of the prism, then the light beam is directed back into the prism, but the excitation light beam is scattered within the prism and measurement accuracy deteriorates
Solution Approach 1:
The patent changes the parameter of the light output surface angle to be smaller than the critical angle for total internal reflection, which prevents total reflection of the excitation beam at the output surface and eliminates scattering within the prism, thereby improving measurement accuracy
3Object-affected harmful factors
If adjustments to the angle of the excitation light beam are made to prevent returning light from entering the light source, then returning light is eliminated, but adjustments are sensitive and difficult for users to perform
Solution Approach 1:
The patent applies preliminary action by pre-designing the prism geometry and light output surface angle to prevent returning light generation in the first place, eliminating the need for user adjustments during operation
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 configuration enhances the accuracy of surface plasmon resonance measurements by preventing returning light from entering the light source, thus improving measurement precision and reducing errors.
Implementation Method 1
Plasmon sensors that utilize the principles of the surface plasmon resonance phenomenon using evanescent waves to quantitatively analyze substances within samples are known
Implementation Method 2
It is necessary to cause an excitation light beam to be totally reflected at the interface between a prism and a metal film provided thereon, in order to cause surface plasmon resonance to occur
Implementation Method 3
a light beam is caused to enter the interface between the prism and the metal film at an angle that satisfies conditions for plasmon resonance, to generate a strong electric field is generated on the metal film
Implementation Method 4
The fluorescent substance is strongly excited by the electric field, and the fluorescence generated thereby is measured
Data Source
AI summary
The shape of a prism is set such that an excitation light beam that enters the prism to cause surface plasmon resonance to be generated is not irradiated onto the corners of the prism after being totally reflected within the prism. The angle of a surface that the excitation light exits the prism is set to an angle at which the excitation light beam is not totally reflected. Thereby, the excitation light beam returning to a light source, and being scattered within the prism are prevented, and therefore the accuracy of measurements can be improved.