Ceramic Position Detecting Member with Roughened Light-Receiving Surface
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Solution Overview
Problem
Existing position detection systems face errors due to irregular reflections and shedding particles obstructing the optical path, which affect the accuracy and reliability of position detection.
Innovation Solution
A position detecting member with a ceramic surface layer having a larger average root mean square slope on the light-receiving surface compared to the back surface, reducing reflectance and increasing contrast, while minimizing shedding and irregular reflections, is used. This surface is made of materials like composite ceramics with aluminum oxide, carbides, or silicon carbide, and is designed to absorb light effectively, reducing temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resin-based scale portion is used with black and white coatings, then position detection is enabled, but shedding particles obstruct the optical path and cause detection errors
Solution Approach 1:
The patent applies composite materials by using a ceramic base portion (aluminum oxide or similar ceramic) instead of resin, combined with a black chromium oxide coating layer. This composite structure eliminates shedding particles while maintaining the low reflectance needed for position detection, directly resolving the contradiction between measurement precision and harmful shedding factors.
2Object-generated harmful factors
If a smooth surface is used on the light-receiving surface, then shedding is reduced, but irregular reflections occur and contrast decreases
Solution Approach 1:
The patent applies local quality by creating a surface with controlled irregularities only on the light-receiving surface (black chromium oxide coated area) while keeping the back surface smooth. The light-receiving surface has intentional roughness to reduce irregular reflections and improve contrast, while the back surface remains smooth to prevent shedding, thus resolving the contradiction locally.
3Object-generated harmful factors
If ceramic material is used for the base portion, then shedding particles are eliminated, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-coating the ceramic base portion with black chromium oxide on the light-receiving surface before final assembly. This preliminary coating process simplifies the overall manufacturing by integrating the low-reflectance property directly into the base portion, eliminating the need for separate resin components and reducing assembly steps.
4Illumination intensity
If the light-receiving surface has high reflectance, then more light is available for detection, but erroneous recognition increases due to irregular reflections
Solution Approach 1:
The patent applies color changes by coating the light-receiving surface with black chromium oxide, which has very low reflectance across the visible spectrum. This black coating absorbs incident light rather than reflecting it irregularly, eliminating erroneous recognition while the ceramic material ensures sufficient light transmission for detection, resolving the contradiction between illumination intensity and measurement precision.
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 solution enhances the accuracy and reliability of position detection by reducing erroneous recognition and shedding, allowing for continuous and precise operation with improved aesthetic quality and product value.
Implementation Method 1
designed to absorb light effectively, reducing temperature increases
Implementation Method 2
an average value of root mean square slopes (RΔq) on the light-receiving surface in a roughness curve is larger than an average value of root mean square slopes (RΔq) on the back surface
Data Source
AI summary
A position detecting member includes a base portion including a light-receiving surface having a black color tone and a back surface located on an opposite side to the light-receiving surface. A surface layer portion including at least the base portion is made of ceramic. An average value of root mean square slopes (RΔq) on the light-receiving surface in a roughness curve is larger than an average value of root mean square slope (RΔq) on the back surface.