Light Irradiation Apparatus Using Diffraction Grating and Scanning Mirror
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Solution Overview
Problem
Conventional light irradiation apparatuses for splitting white light into multiple wavelengths with a time difference require complex configurations, making them expensive and impractical for applications like wafer thickness measurement.
Innovation Solution
A light irradiation apparatus comprising a white light source, a diffraction grating for splitting white light into multiple wavelengths, and a light selector using a pinhole mask and optical path conversion mirrors, such as galvanoscanners or polygon mirrors, to select specific wavelengths with a time difference, resulting in a simpler and more cost-effective configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional spectroscopic means are used to split white light into multiple wavelengths with a time difference, then the wavelength separation function is achieved, but the device configuration becomes complicated and expensive
Solution Approach 1:
The patent replaces conventional complex spectroscopic means with a diffraction grating combined with a scanning mirror system. The diffraction grating disperses white light into multiple wavelengths spatially, and the scanning mirror sequentially selects different wavelengths by changing its reflection angle, achieving time-resolved wavelength selection with a much simpler mechanical-optical system.
Solution Approach 2:
The patent introduces dynamic wavelength selection through a scanning mirror that changes its angle over time. By dynamically adjusting the mirror angle, the system sequentially directs different wavelengths from the diffraction grating to the detector, enabling time difference measurement between multiple wavelengths without requiring complex static optical paths for each wavelength.
2Device complexity
If conventional spectroscopic means are used to split white light, then accurate wavelength measurement is achieved, but the cost of the device increases
Solution Approach 1:
The patent substitutes expensive conventional spectroscopic instruments with a cost-effective combination of diffraction grating and scanning mirror. The diffraction grating provides precise wavelength-dependent spatial separation, and the scanning mirror enables sequential wavelength selection, achieving accurate wavelength measurement at a fraction of the cost of traditional spectroscopic systems.
Solution Approach 2:
The patent introduces a scanning mirror as an intermediary component between the diffraction grating and the detector. This intermediary dynamically redirects different wavelengths at different times, enabling precise wavelength measurement through temporal separation while using inexpensive optical components instead of expensive spectroscopic instruments.
3Reliability
If a simple light splitting configuration is used, then the device cost is reduced, but the ability to split white light into multiple wavelengths with time difference is compromised
Solution Approach 1:
The patent employs periodic scanning of the mirror to achieve time-resolved wavelength separation. The mirror angle is periodically changed to sequentially direct different wavelengths from the diffraction grating to the detector, creating a time difference between wavelength measurements. This periodic action enables multi-wavelength analysis with temporal resolution using a simple optical configuration.
Solution Approach 2:
The patent uses dynamic mirror scanning to convert a static optical system into a time-resolved measurement system. By dynamically changing the mirror angle over time, the system achieves temporal separation of wavelengths, maintaining reliable time difference measurement capability while keeping the optical configuration simple and inexpensive.
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
Enables the efficient and cost-effective splitting of white light into multiple wavelengths with a time difference, suitable for applications like wafer thickness measurement, by using a straightforward optical system that reduces complexity and costs.
Implementation Method 1
a diffraction grating that splits white light emitted from the white light source into light rays of a plurality of wavelengths
Implementation Method 2
a first focusing mirror that reflects the light rays of the plurality of wavelengths split by the diffraction grating
Data Source
AI summary
A light irradiation apparatus that splits white light into light rays of a plurality of wavelengths to apply the light ray includes a white light source, a diffraction grating that splits white light emitted by the white light source into light rays of a plurality of wavelengths, and a light selector that selects a light ray of a specified wavelength from the light rays of the plurality of wavelengths split by the diffraction grating.