Position Measuring Device With Segmented Linear Scales
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Manufacturing linear scales longer than 3 meters with special materials like Zerodur is difficult, posing a challenge for precise position measurement in large-sized substrate processing apparatuses.
Innovation Solution
A position measuring device utilizing multiple linear scales and scale heads that are activated and deactivated alternately to measure the position of a movable member, allowing for accurate displacement measurement beyond 3 meters by using a plurality of linear scales arranged in a line with gaps between them, and activating/deactivating scale heads accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single long linear scale is used for position measurement, then measurement precision is improved, but manufacturing difficulty increases significantly
Solution Approach 1:
The patent divides a long linear scale into multiple shorter linear scales (first linear scale, second linear scale, etc.) arranged in sequence. Each linear scale can be manufactured separately using conventional techniques, avoiding the manufacturing difficulties of single long scales while maintaining continuous position measurement capability across the entire range.
2Length of stationary object
If multiple linear scales are used to extend measurement range, then measurement range is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple linear scales and multiple scale heads into an integrated position measuring device. The controller coordinates the multiple scale heads to read from appropriate linear scales based on position, merging their functions into a unified measurement system that extends the measurement range while managing complexity through centralized control.
Solution Approach 2:
The patent implements dynamic activation and deactivation of scale heads based on the position being measured. Scale heads are selectively activated or deactivated opposite to each other depending on which linear scale is currently being read, optimizing system performance and reducing unnecessary operational complexity.
Data Source
AI summary
A position measuring device and a position measuring method for accurately measuring a position of a movable member using a plurality of linear scales are provided. The position measuring device comprises a first linear scale elongated in a first direction, a second linear scale elongated in the first direction and separated from the first linear scale, and a head structure including a first scale head and a second scale head that are spaced apart from each other, wherein the head structure reads the first linear scale or the second linear scale while moving in the first direction, wherein the first scale head and the second scale head are activated or deactivated opposite to each other.