Transparent Plate Shape Measurement Using Reflection Spot Separation
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Solution Overview
Problem
Conventional methods for measuring the surface shape of transparent flat plates, such as JP-A-2009-128098, require complex setups and struggle to accurately separate and identify first and second surface reflection images, leading to difficulties in determining the exact surface shape.
Innovation Solution
A shape measuring apparatus and method that uses an image pick-up section with a perpendicular optical axis to capture and separate reflection spot groups from the first and second surfaces of the transparent flat plate, estimating the first surface reflection spot group and calculating the inclination angle to determine the surface shape in cross sections perpendicular to the image separation direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex pattern design and multiple line sensors are used to separate reflection images, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts and separates the first surface reflection image from the second surface reflection image by utilizing the different positions of reflection spot groups. By identifying and isolating the first surface reflection spot group from the image, the system eliminates the interference from the second surface reflection, achieving accurate surface shape measurement without requiring complex pattern designs or multiple sensors.
Solution Approach 2:
The patent segments the reflection images into distinct first surface reflection spot groups and second surface reflection spot groups. By dividing the image into separable components based on their spatial positions, the system enables independent analysis of each reflection type, allowing accurate measurement of the first surface shape while excluding the second surface reflection interference.
2Measurement precision
If complex pattern designs are used to separate reflection images, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent simplifies the measurement process by extracting only the essential first surface reflection spot group from the image, eliminating the need for complex pattern designs. The system automatically identifies and isolates the relevant reflection information, making the operation straightforward while maintaining high measurement precision.
3Measurement precision
If conventional reflection image separation methods are used, then surface shape can be measured, but reliability deteriorates due to difficulty in identifying first surface reflection
Solution Approach 1:
The patent enhances reliability by extracting and focusing exclusively on the first surface reflection spot group, which contains the accurate surface shape information. By isolating this specific reflection component and excluding the second surface reflection, the system ensures consistent and reliable identification of the first surface reflection, eliminating ambiguities in measurement.
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 allows for a simple and accurate measurement of the surface shape of transparent flat plates, ensuring precise determination of surface features like fine waviness without the need for complex equipment or pattern designs.
Implementation Method 1
an image pick-up section which is arranged such that an optical axis of the image pick-up section is perpendicular to a direction of extending of a linear pattern arranged above a transparent flat plate serving as a measurement object, the image pick-up section being configured to capture an image of two reflection spot groups of the pattern generated by a first surface and a second surface of the transparent flat plate
Data Source
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AI summary
A simple construction is allowed to achieve accurate measurement of the surface shape of a transparent flat plate. A shape measuring apparatus includes: an image pick-up section 2 that is arranged such that an optical axis becomes perpendicular to a direction of extending of a linear pattern X arranged above a transparent flat plate 3 serving as a measurement object and that captures an image of two reflection spot groups of the pattern X reflected in a first surface M1 and a second surface M2 of the transparent flat plate 3 and generates an image containing two reflection images separated in a direction perpendicular to the direction of extending; a first surface reflection spot group estimating section that estimates from the image a first surface reflection spot group A of the pattern X generated by the first surface M1 of the transparent flat plate 3 by using a positional relation of the transparent flat plate 3, the pattern X, and the image pick-up section 2; an inclination angle calculating section that calculates an inclination angle of the first surface M1 of the transparent flat plate 3 at an estimated position of the first surface reflection spot group A by using the positional relation of the transparent flat plate 3, the pattern X, and the image pick-up section 2; and a surface shape determining section that determines a shape of the first surface M1 of the transparent flat plate 3 based on the calculated inclination angle.