Reflection Optical Encoder Scale With Chromium Low-Reflectance Regions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional reflection-type optical encoder scales do not sufficiently reduce reflectance in the red/near infrared region, leading to potential false detections and reduced detection accuracy.
Innovation Solution
The optical encoder scale features low reflection regions with a three-layered structure comprising a metallic chromium film, chromium oxide film, and chromium nitride film, arranged in specific orders, to reduce reflectance to 10% or less in the wavelength range of 550 nm to 950 nm, and high reflection regions with a metallic chromium film or silver alloy film to enhance reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional multilayered structures including SiO2 and Ti are used to reduce reflectance in low reflection regions, then reflectance is reduced, but manufacturing cost increases due to expensive materials and multiple raw materials required
Solution Approach 1:
The invention changes the material parameters by replacing expensive SiO2 and Ti materials with chromium-based materials (Cr, Cr2O3, CrN), achieving the same reflectance reduction effect while lowering manufacturing costs and simplifying material requirements
Solution Approach 2:
The invention uses composite chromium-based materials (combination of Cr, Cr2O3, and CrN layers) to achieve effective reflectance reduction, maintaining detection accuracy while reducing dependency on expensive and varied raw materials
2Ease of manufacture
If conventional low reflection region structures are used, then manufacturing is simpler, but reflectance in the red/near infrared region is not sufficiently reduced leading to false detections
Solution Approach 1:
The invention employs a composite structure of chromium metal film, chromium oxide film, and chromium nitride film in specific layer combinations, achieving sufficient reflectance reduction in the red/near infrared region while maintaining manufacturing feasibility through a standardized three-layer configuration
Solution Approach 2:
The invention applies specific chromium-based material combinations only to the low reflection regions, maintaining manufacturing simplicity while locally achieving the required reflectance reduction to prevent false detections
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 configuration significantly increases the reflectance difference between high and low reflection regions, preventing false detections and improving detection accuracy by ensuring a high signal-to-noise ratio.
Implementation Method 1
a chromium oxide film and a chromium nitride film which are placed on a metallic chromium film... capable of sufficiently reducing reflectance on low reflection regions
Implementation Method 2
a chromium oxide film and a chromium nitride film which are placed on a metallic chromium film... to reduce reflectance to 10% or less
Implementation Method 3
the high reflection regions have higher reflectance of incident light... the high reflection regions include a metallic chromium film or a silver alloy film
Data Source
Figure 1A~2
Figure 3A~3B
Figure 4A~4C
AI summary
A main object of the present disclosure is to provide a reflection-type optical encoder scale capable of sufficiently reducing the reflectance on a low reflection region. The present disclosure achieves the object by providing a reflection-type optical encoder scale comprising a high reflection region and a low reflection region alternately placed on a substrate, wherein the low reflection region includes a low reflection portion including a metallic chromium film formed on the substrate, and a chromium oxide film and a chromium nitride film randomly formed on the metallic chromium film; and the high reflection region has higher reflectance of incident light from opposite side to the substrate of the reflection-type optical encoder scale, than the low reflection region.