Inner Layer Measurement Using Dynamic Optical Filters
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Solution Overview
Problem
Existing inner layer measurement devices suffer from decreased spatial resolution due to the longer wavelength of near infrared light, which is affected by diffraction, leading to inaccurate measurements.
Innovation Solution
The method employs a light interferometer with a short pass filter and a long pass filter that change their cutoff wavelengths based on position, emitting both first and second irradiation lights with different wavelength bands to improve spatial resolution by adjusting the peak wavelength and bandwidth according to the depth of the semitransparent body's layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If near infrared light is used for measuring deeper layers of the semitransparent body, then the penetration depth is improved, but the spatial resolution deteriorates due to diffraction
Solution Approach 1:
The measurement process is segmented into multiple wavelength bands: visible light (400-700nm) for surface and shallow layers, and near infrared light (700-2000nm) for deeper layers. This segmentation allows each wavelength band to be optimized for its specific depth range, resolving the contradiction between penetration depth and spatial resolution.
Solution Approach 2:
The system dynamically switches between different wavelength bands based on the depth of the layer being measured. The light source can adjust its peak wavelength and bandwidth according to the measurement depth, using visible light for high-resolution surface measurements and near infrared light for deeper penetration when needed.
2Measurement precision
If visible light with shorter wavelength is used, then the spatial resolution is improved, but the penetration depth deteriorates
Solution Approach 1:
The visible light spectrum is segmented and selectively used for measuring surface and shallow layers where high spatial resolution is required. The system divides the measurement task into depth-specific wavelength bands, assigning visible light to superficial measurements and near infrared light to deeper measurements.
Solution Approach 2:
The system changes the wavelength parameter of the irradiation light based on the measurement depth. By adjusting the peak wavelength and bandwidth of the light source, the system optimizes the balance between spatial resolution and penetration depth for each specific measurement scenario.
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 enhances the spatial resolution of inner layer measurements by using visible light for surface layers and near infrared light for deeper layers, resulting in improved XYZ resolution compared to traditional methods.
Implementation Method 1
Each of the short pass filter and the long pass filter is capable of transmitting the light and has properties of changing a cutoff wavelength in response to the position at which the light is transmitted
Implementation Method 2
the interference microscope applies a phase modulation of the degree of a wavelength of light to a difference in an optical path length between measurement light and reference light
Implementation Method 3
the longer wavelength of near infrared light, which is affected by diffraction
Data Source
AI summary
In an inner layer measurement method, first irradiation light and second irradiation light having a peak wavelength longer than that of the first irradiation light are formed by changing at least one of a position where light emitted from a lamp is transmitted through a short pass filter and a position where light emitted from a lamp is transmitted through a long pass filter. Then, a first XY sectional surface of a semitransparent body is measured by irradiating the first XY sectional surface with the first irradiation light. A second XY sectional surface positioned on a layer deeper than the first XY sectional surface is measured by irradiating the second XY sectional surface with the second irradiation light. Each of the short pass filter and the long pass filter can transmit the light and has properties of changing a cutoff wavelength according to the position where the light is transmitted.