Standard-Light Generator for Submicron Straightness Measurement
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Solution Overview
Problem
Conventional straightedges cannot achieve submicron-order straightness measurement accuracy due to limitations in laser beam divergence and energy distribution, making it impractical for high-precision flatness measurements in manufacturing devices.
Innovation Solution
A standard-light generator with a circular-ring-shaped light transparency slit and a light shielding plate, where a light source is positioned on the slit axis, and a photoreceiver is used to specify the center position of a diffraction-interference beam pattern for accurate straightness measurement, reducing measurement errors and stray light issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional laser beam is used for straightness measurement, then the measurement can be performed, but the measurement precision is limited to micrometer order due to beam divergence and large cross-section diameter
Solution Approach 1:
The invention segments the light beam by passing it through a circular aperture, dividing the beam into a central core region and peripheral regions. This segmentation allows selective utilization of the central portion of the beam for measurement, effectively reducing the functional beam diameter while maintaining the original light source properties.
Solution Approach 2:
The invention applies local quality by focusing measurement on the central region of the beam cross-section where energy distribution is most stable and symmetric. The circular aperture selectively transmits only the central portion, creating a localized measurement zone with superior precision characteristics compared to the entire beam cross-section.
2Measurement precision
If the incident position of the laser beam is specified for measurement, then measurement can be performed, but measurement errors occur due to asymmetry in energy distribution and difficulty in precisely locating the beam center
Solution Approach 1:
The invention deliberately introduces asymmetry in the form of a circular aperture that creates a symmetric diffraction pattern. The circular geometry provides a well-defined center point that is inherently easier to locate with high precision compared to the asymmetric energy distribution of the original laser beam, thus simplifying center determination while improving accuracy.
Solution Approach 2:
The circular aperture acts as an intermediary element between the laser beam and the measurement system. It transforms the difficult-to-locate beam center into an easily identifiable diffraction pattern center, serving as a mediator that simplifies the position specification task while maintaining measurement integrity.
3Measurement precision
If conventional straightedges are used for flatness measurement, then measurement can be performed, but submicron-order precision cannot be achieved due to mechanical limitations
Solution Approach 1:
The invention replaces the mechanical straightedge system with an optical measurement system. Instead of relying on mechanically fabricated straightedges with inherent precision limits, the system uses light diffraction patterns to establish a reference, thereby achieving submicron-order precision that transcends mechanical manufacturing capabilities.
Solution Approach 2:
The invention changes the fundamental parameter from mechanical dimension (straightedge geometry) to optical parameter (diffraction pattern). This parameter transformation enables precision measurement at the submicron level by utilizing wave optical properties rather than mechanical tolerances, fundamentally overcoming the precision limits of conventional straightedges.
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 enables high-accuracy straightness measurement beyond conventional limits, providing a reliable standard for longer-range measurements without the limitations of mechanical standards, achieving submicron-order precision and minimizing measurement errors.
Implementation Method 1
irradiating the whole area of the light transparency slit with light from the light source, observing irradiance by diffraction light waves from the light transparency slit
Implementation Method 2
observing irradiance by diffraction light waves from the light transparency slit... specifying a position at which the irradiance has a peak due to interference of the diffraction light waves
Data Source
Figure 1
Figure 2(1)~2(2)
Figure 3
AI summary
A standard-light generator for straightness measurement has a light source, and a light shielding plate disposed at a position irradiated with light from the light source. The light shielding plate has a circular-ring-shaped light transparency slit. The light source is disposed on a slit axis through the center of the circumference of the light transparency slit and perpendicular to the light shielding plate, and directed so that the whole area of the light transparency slit is irradiated with light from the light source. In measuring straightness, observed are irradiances by diffraction light waves from the light transparency slit on a first, second and third observation planes respectively different in distance to the light shielding plate. Each position of each irradiance peak due to interference of the diffraction light waves is specified.