Off-Axis Parabolic Mirror Relay for Wide-Band Spectroscopy
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Solution Overview
Problem
Existing optical microscopes face challenges in performing measurements across a wide wavelength band due to chromatic aberration, particularly in regions like deep ultraviolet and near-infrared, where available lens materials are limited and cannot correct for aberrations effectively.
Innovation Solution
The optical microscope employs a configuration where the focal lengths of the first and second off-axis parabolic mirrors are equal, and specific ratios of distances between these mirrors and other optical components are maintained to ensure the light beam passes through the center of the objective lens' entrance pupil, minimizing changes in laser intensity and spatial resolution. Additionally, correcting lenses and a focus optical system with spherical mirrors are used to correct various aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lenses are used in the optical system to guide and focus light beams, then the optical system can be compact and easy to manufacture, but chromatic aberration occurs that prevents measurement in a wide wavelength band
Solution Approach 1:
The patent replaces the lens-based refractive optical system with a mirror-based reflective optical system. Specifically, off-axis parabolic mirrors are used to guide and focus light beams throughout the optical path, eliminating chromatic aberration since mirrors reflect all wavelengths equally. This substitution enables wide wavelength band measurement from deep ultraviolet to near-infrared regions while maintaining optical functionality.
Solution Approach 2:
The patent changes the fundamental optical parameter from refraction (lenses) to reflection (mirrors). By using off-axis parabolic mirrors with specific focal lengths and positioning them at precise distances, the system achieves aberration-free wide-band spectroscopic measurement. The parameter change from refractive index dependence to reflective geometry enables universal wavelength coverage.
2Adaptability or versatility
If multiple lens materials are combined to correct chromatic aberration, then measurement in wide wavelength band becomes possible, but the system becomes complex and many optical glasses are opaque in deep ultraviolet region
Solution Approach 1:
The patent eliminates the need for multiple lens materials by substituting the entire lens-based refractive system with a mirror-based reflective system. Off-axis parabolic mirrors correct all types of aberrations simultaneously without requiring material combinations, thereby simplifying the system while achieving wide wavelength band coverage including deep ultraviolet regions where most optical glasses are opaque.
3Productivity
If the beam spot is extended in one direction to illuminate the sample in a line form, then the measurement period is reduced and sample damage is prevented, but spatial resolution may be compromised
Solution Approach 1:
The patent segments the measurement process by extending the beam spot in one direction to illuminate a line of the sample simultaneously. This allows parallel measurement of multiple points along the line, effectively increasing measurement speed. The off-axis parabolic mirrors maintain focus quality across the extended beam profile, preserving spatial resolution while enabling rapid line-by-line scanning of the sample.
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 significantly reduces aberrations, enabling accurate spectroscopic measurements across a wide wavelength band from deep ultraviolet to near-infrared regions without compromising spatial resolution or laser intensity.
Implementation Method 1
a first relay optical system including a first off-axis parabolic mirror that is arranged in an optical path from the first scanner to the objective lens and reflects the light beam deflected by the first scanner and a second off-axis parabolic mirror that reflects the light beam reflected in the first off-axis parabolic mirror
Implementation Method 2
the objective lens configured to focus the light beam deflected by the first scanner
Implementation Method 3
the objective lens configured to focus the light beam deflected by the first scanner and cause the light beam to be made incident on the sample
Implementation Method 4
the spectroscope configured to spatially disperse the outgoing light emitted from an area on the sample onto which the light beam has been illuminated in accordance with the wavelength
Data Source
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AI summary
An optical microscope (100) according to one aspect of the present disclosure includes: a light source (10); a first scanner configured to scan a spot position of a light beam on a sample; an objective lens (21) configured to focus the light beam deflected by the first scanner and cause the light beam to be made incident on the sample; a spectroscope (31) including a slit on an incident side which an outgoing light emitted from an area on the sample onto which the light beam has been illuminated enters; a detector (32) configured to detect an outgoing light from the spectroscope (31); and a first relay optical system (300) including a first off-axis parabolic mirror (301) that is arranged in an optical path from the first scanner to the objective lens (21) and reflects the light beam deflected by the first scanner and a second off-axis parabolic mirror (302) that reflects the light beam reflected in the first off-axis parabolic mirror (301).