Measuring Scale Held by Pneumatic Suction on Grid Supports
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Solution Overview
Problem
Existing methods for securing a scale to a substrate for position measurement are prone to errors due to interference from contaminants and air bubbles with pneumatic suction, and optical contact bonding methods struggle to maintain homogeneous contact pressure, especially in large-area scales.
Innovation Solution
A scale is secured to a substrate using two-dimensionally distributed supports with a mutual period less than the scale's thickness, preventing optical contact bonding and ensuring a sealed space for homogeneous pneumatic suction, which maintains constant contact pressure and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pneumatic suction is used to hold the scale against the substrate, then the scale can be secured to the substrate, but contaminants and air bubbles interfere with the connection causing length changes and measurement errors
Solution Approach 1:
The invention divides the contact area into multiple discrete support points arranged in a grid pattern, rather than using continuous contact. This segmentation allows pneumatic suction to act at multiple localized points, preventing contaminants and air bubbles from interfering with the entire connection while maintaining stable holding forces across the scale surface.
2Reliability
If optical contact bonding elements are used to secure the scale, then the scale can be fastened to the substrate, but the contact pressure is not homogeneous over the entire measuring graduation plane
Solution Approach 1:
The invention uses pneumatic suction forces distributed across multiple support points to hold the scale against the substrate. This pneumatic approach provides homogeneous contact pressure across the entire measuring graduation plane, eliminating the non-uniform stress distribution inherent in optical contact bonding methods while maintaining secure fastening.
3Area of stationary object
If large-area optical contact bonding elements are used, then the scale can be secured over a large area, but disturbances in the contact face cause detachment of the entire bonding element
Solution Approach 1:
The invention segments the large contact area into multiple discrete support points arranged in a grid pattern. This segmentation ensures that disturbances at any single contact face cannot propagate to detach the entire bonding element, as each support point operates independently. The grid arrangement maintains large-area coverage while preventing cascade failures.
4Reliability
If the scale rests on the substrate with pneumatic suction, then the scale can be held in place, but air bubbles and contaminants cause changes in length and location of measuring graduation
Solution Approach 1:
By dividing the contact interface into multiple discrete support points, the invention prevents air bubbles and contaminants from forming continuous layers between the scale and substrate. The segmented support structure ensures that even if minor contamination occurs at individual points, it cannot cause systematic length changes or shifts in the measuring graduation across the entire scale.
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 approach ensures stable and accurate position measurement by preventing length changes and maintaining high measurement accuracy, with uniform holding forces and preserved surface smoothness, avoiding the drawbacks of large-area contact bonding.
Implementation Method 1
the scale is held on the substrate by pneumatic suction
Implementation Method 2
a suction conduit is provided outside the measuring graduation and is intended to force the scale, over its entire length, against the substrate with a constant contact pressure
Data Source
AI summary
An assembly including a substrate and a scale held on the substrate, wherein the scale has a measuring graduation, and the scale is held on the substrate by pneumatic suction. The scale is braced on the substrate via two-dimensionally distributed, spaced-apart supports, which are disposed facing a measurement area defined by the measuring graduation and wherein adjacent ones of the supports are spaced apart from one another at a mutual period that is less than a thickness of the scale. In addition, the supports have a structure such that a connection by optical contact bonding between the supports and the scale and/or between the supports and the substrate is prevented at least in the measurement area. A space between the scale and the substrate is sealed off from surroundings by a sealing structure.