Specular Surface Shape Measurement Without Beam-Splitting Optics
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Solution Overview
Problem
Existing surface shape measuring apparatuses for specular surfaces are often large in size due to oblique illumination and the use of semi-transparent mirrors, which increases their dimensions.
Innovation Solution
A surface shape measuring apparatus that illuminates the specular surface with a first light pattern and captures a second light pattern transmitted through the illuminator, using an imaging device aligned normal to the surface, without a splitting and merging optical system, and processes the positional deviation of the second light pattern to determine the surface shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oblique illumination is used to measure specular surface, then measurement capability is achieved, but apparatus size increases
Solution Approach 1:
Instead of using oblique illumination as in conventional techniques, this patent employs normal (perpendicular) illumination to illuminate the specular surface. The imaging device also captures images from the normal direction, inverting the conventional oblique arrangement. This inversion enables specular surface measurement while reducing apparatus size, as the illumination and imaging paths are aligned rather than separated at oblique angles.
2Adaptability or versatility
If semi-transparent mirror is used to split light paths, then inspection capability is improved, but apparatus size increases
Solution Approach 1:
This patent removes the semi-transparent mirror component from the optical system. By extracting this element, the patent eliminates the need for complex light path splitting and merging mechanisms. The illumination and imaging are performed directly along the normal direction without requiring beam splitting, thereby reducing apparatus size while maintaining inspection capability through alternative optical path design.
3Ease of operation
If splitting and merging optical system is disposed between specular surface and camera, then light path control is achieved, but apparatus size increases
Solution Approach 1:
The patent merges the illumination path and imaging path into a single normal direction alignment. Instead of using separate splitting and merging optical systems for different light paths, the illumination unit and imaging device are positioned to operate along the same normal axis, combining the optical paths and eliminating the need for additional beam splitting components, thus reducing apparatus size.
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
The apparatus is reduced in size and simplifies surface shape measurement by eliminating the need for oblique illumination and semi-transparent mirrors, while accurately determining the surface shape through positional deviation analysis.
Implementation Method 1
an imaging device configured to capture an image of a second light pattern which is light transmitted through the illuminator after the first light pattern from the illuminator is reflected by the specular surface
Data Source
AI summary
A surface shape measuring apparatus for measuring a specular surface includes an illuminator configured to illuminate the specular surface with a first light pattern, an imaging device configured to capture an image of a second light pattern which is light transmitted through the illuminator after the first light pattern from the illuminator is reflected by the specular surface, and a processing apparatus configured to acquire a positional deviation amount of the second light pattern from a predetermined position in the image captured by the imaging device, and to output information related to a surface shape of the specular surface acquired from the positional deviation amount.