Index-Matched Liquid Reduces Backside Reflections
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Solution Overview
Problem
Existing systems face difficulties in reducing backside reflections of electromagnetic radiation from samples when a beam is incident at an oblique or normal angle, especially in systems with continuously moving samples, which complicates the characterization of surface films.
Innovation Solution
A system comprising a sample, a means for supporting the sample with matched refractive indices or an index-matched liquid interface, and a detector to minimize backside reflections by positioning the support under the sample near the incidence location, allowing the beam to impinge at an oblique or normal angle and reflect into the detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a beam of electromagnetic radiation is caused to impinge on the surface of a sample at an oblique or normal angle, then surface reflection characterization is enabled, but backside reflections complicate the results and make characterization difficult or impossible
Solution Approach 1:
An index-matched liquid is introduced as an intermediary substance between the sample and the support means. This liquid has a refractive index that matches both the sample and the support means, creating gradual refractive index transitions that eliminate abrupt interfaces and thereby eliminate backside reflections while preserving surface reflection measurements
2Device complexity
If the sample and means for supporting it have different refractive indices, then support structure is simplified, but backside reflections develop and complicate measurements
Solution Approach 1:
The index-matched liquid serves as a mediator layer between the sample and support means, allowing the support structure to remain simple while the liquid eliminates backside reflections through refractive index matching. This maintains structural simplicity without sacrificing measurement precision
3Measurement precision
If a deformable means for supporting a sample is used with a rigid sample, then good contact is achieved reducing backside reflections, but system complexity increases
Solution Approach 1:
A deformable support means is used that can dynamically adapt its shape to conform to the rigid sample surface. This dynamic deformation capability allows the support to achieve intimate contact with the sample, eliminating air gaps and backside reflections, while the deformability itself is a simple property of the support material
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 approach effectively reduces backside reflections, enabling accurate characterization of surface films by isolating the surface reflections from the sample's backside reflections, even in systems with continuous relative motion between the sample and its support.
Implementation Method 1
When a beam of electromagnetic radiation is caused to impinge on the surface of a sample at an oblique or normal angle, reflected electromagnetic radiation from said sample generally contains components not only from its surface, but also from the backside thereof. The effect of said backside reflections can be difficult to model, and makes characterization of surface films far more difficult, even essentially impossible. It is therefore desirable to reduce or eliminate the presence of said backside reflections.
Implementation Method 2
Said means for supporting a sample and said sample can be characterized by a selection from the group consisting of: having substantially matched indices of refraction; and having liquid present at the interface therebetween which is substantially index matched to that of said sample.
Data Source
AI summary
A system for reducing reflections of a beam of electromagnetic from the back of a sample, including methodology of use.