Low Expansion Glass Scale Grating Stability
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Solution Overview
Problem
Existing diffraction gratings, particularly those made of resin, suffer from chronological degradation and are sensitive to environmental temperature changes due to high thermal expansion coefficients, which affects their accuracy and stability.
Innovation Solution
A scale with a substrate made of low expansion glass (thermal expansion coefficient of 1×10−7/K or less) and gratings made of transparent inorganic materials (thermal expansion coefficient greater than 1×10−7/K) are used, along with a manufacturing method that forms these gratings on the substrate at a predetermined interval, providing enhanced environmental resistance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resin is used as grating material, then manufacturing ease is improved, but chronological stability and environment resistance deteriorate
Solution Approach 1:
The patent uses a composite structure combining low expansion glass substrate with transparent inorganic material gratings. This composite approach allows the substrate to provide dimensional stability while the inorganic grating material provides environmental resistance, resolving the contradiction between ease of manufacture and chronological stability.
2Ease of manufacture
If synthetic quartz is used as substrate, then processing ease is improved, but temperature stability deteriorates due to high thermal expansion coefficient
Solution Approach 1:
The patent changes the thermal expansion parameter by selecting low expansion glass with a thermal expansion coefficient of 1×10−7/K or less, which is one order of magnitude lower than synthetic quartz. This parameter change achieves superior temperature stability while maintaining compatibility with standard glass processing techniques.
3Temperature
If zero expansion glass is used as substrate, then temperature stability is improved, but processing difficulty increases
Solution Approach 1:
The patent applies local quality by forming gratings with different thermal expansion properties (transparent inorganic material with coefficient >1×10−7/K) on the low expansion glass substrate. This allows the substrate to maintain overall temperature stability while the grating regions provide the necessary optical functionality and etchability.
4Device complexity
If gratings are made of resin, then manufacturing simplicity is improved, but environment resistance deteriorates
Solution Approach 1:
The patent replaces organic resin gratings with inorganic material gratings that have superior environmental resistance. While inorganic materials may require more complex formation processes, they eliminate the chronological degradation and environmental sensitivity issues associated with organic materials, providing long-term stability.
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 suppresses chronological degradation and temperature-induced influences, ensuring the scale's accuracy and stability, while improving the yield and throughput of grating formation by maintaining a specific diffraction index relationship.
Implementation Method 1
a substrate that is made of low expansion glass of which a thermal expansion coefficient is 1×10−7/K or less
Implementation Method 2
scale gratings having a plurality of gratings that are arranged on a first face of the substrate at a predetermined interval
Data Source
AI summary
A scale includes: a substrate that is made of low expansion glass of which a thermal expansion coefficient is 1×10−7/K or less; and scale gratings having a plurality of gratings that are arranged on a first face of the substrate at a predetermined interval and are made of a transparent inorganic material of which a thermal expansion coefficient is more than 1×10−7/K.