Surface Profile Measuring Apparatus with Dynamic Light Flux Aperture
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Solution Overview
Problem
Conventional surface profile measuring apparatuses face challenges in accurately measuring curved surfaces and small areas due to variations in measurement values caused by changes in the cross section of the projection light flux, leading to increased errors and the need for multiple apparatuses or averaging processes.
Innovation Solution
A surface profile measuring apparatus with a changing section that adjusts the cross section of the light flux projected onto the sample, allowing for precise measurement of curved surfaces and small areas using a single apparatus by switching between large and small apertures, thereby minimizing measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large cross section of projection light flux is used to illuminate a curved surface, then the illumination area is increased, but the measurement precision deteriorates due to light scattering and inability to accurately receive specular reflection light
Solution Approach 1:
The patent applies the dynamics principle by making the cross section of the projection light flux changeable during measurement. The light flux cross section is dynamically adjusted to be small when measuring curved surfaces to prevent light scattering and improve measurement accuracy, while being large when measuring flat surfaces to increase illumination area and reduce measurement time. This dynamic adaptation resolves the contradiction between illumination area and measurement precision.
Solution Approach 2:
The patent applies parameter changes by varying the cross section size of the projection light flux based on the sample surface characteristics. The system changes the light flux parameter (cross section size) from large to small depending on whether the surface is flat or curved, thereby optimizing both illumination area and measurement precision for different measurement conditions.
2Measurement precision
If a small cross section of projection light flux is used to measure curved surfaces, then the measurement precision is improved, but the productivity decreases due to reduced illumination area requiring multiple measurements
Solution Approach 1:
The system dynamically adjusts the light flux cross section size based on the measurement requirements. When measuring curved surfaces, it uses a small cross section for high precision; when measuring flat surfaces, it switches to a large cross section to illuminate the entire area at once, thereby maintaining high productivity. This dynamic switching resolves the contradiction between measurement precision and productivity.
Solution Approach 2:
The patent changes the light flux cross section parameter adaptively: small cross section for curved surface measurement to ensure precision, and large cross section for flat surface measurement to maintain productivity. This parameter change strategy allows the system to optimize both precision and productivity for different measurement scenarios.
3Area of stationary object
If a fixed large aperture is used for illumination, then the illumination area is maximized for flat surfaces, but the device complexity increases when multiple apparatuses are needed for curved surfaces
Solution Approach 1:
The patent applies universality by designing a single measuring apparatus that can handle both flat and curved surfaces. The key is the changeable light flux cross section that adapts to different surface types, eliminating the need for separate apparatuses for flat and curved surface measurement. This multi-functionality reduces device complexity while maintaining large illumination area capability for flat surfaces.
Solution Approach 2:
The system uses a dynamic light flux cross section that can be adjusted between large and small sizes within a single apparatus. This dynamic capability allows one device to perform multiple functions (measuring both flat and curved surfaces), thereby reducing the overall device complexity compared to using separate fixed-aperture apparatuses for each surface type.
4Measurement precision
If multiple measurement positions are measured and averaging process is performed to reduce errors, then the measurement precision is improved, but the loss of time increases due to multiple measurements
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the light flux cross section size according to the sample surface characteristics before measurement begins. For curved surfaces, the system sets the light flux to a small cross section in advance, which prevents light scattering and ensures high measurement precision in a single measurement, thereby avoiding the time loss associated with multiple measurements and averaging processes.
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 easy and precise measurement of surface profiles on curved or small areas in a short time without requiring different apparatuses, reducing measurement variations and errors by adapting the light flux cross section based on the sample's surface characteristics.
Implementation Method 1
A light flux from a light source has passed through an illumination aperture
Implementation Method 2
a specular reflection component of light reflected on the sample surface is converged on a light receiving lens
Implementation Method 3
the light flux from the light source has passed through an illumination aperture having a rectangular opening in an aperture plate, is irradiated onto a sample surface through an illumination lens
Implementation Method 4
a specular reflection component of light reflected on the sample surface is converged on a light receiving lens, and the converged light is received on a light receiving device
Data Source
AI summary
A surface profile measuring apparatus of the invention has a changing section for changing the cross section of a flux of light to be projected onto a sample by a light projecting section in measuring a surface profile of the sample. The surface profile measuring apparatus having the above arrangement enables to measure the surface profile of the sample easily and precisely, without using different kinds of measuring apparatuses.