Optical Encoder Two-Dimensional Displacement Detection
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Solution Overview
Problem
Existing displacement sensor configurations for detecting two-dimensional displacement of a scale light imaging configuration relative to a one-dimensional scale grating are overly complex.
Innovation Solution
A displacement sensor configuration with a simpler structure, utilizing a scale grating and a scale light imaging configuration that includes an illumination portion, imaging configuration with deflecting elements and a telecentric imaging portion, and detectors to output and receive scale light components along specific optical paths, allowing for the detection of displacements in multiple directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a displacement sensor configuration is used to detect two-dimensional displacement of a scale light imaging configuration relative to a one-dimensional scale grating, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a second optical path inclined at an angle to the first optical path, enabling detection in a second dimension (Z-direction) in addition to the primary X-direction measurement. This dimensional extension allows two-dimensional displacement detection while maintaining a relatively simple sensor structure by adding only one additional optical path and detector portion.
Solution Approach 2:
The detector is divided into first and second detector portions, each receiving light from different optical paths. This segmentation allows independent processing of signals from different measurement dimensions, enabling two-dimensional displacement detection through separate signal channels that can be processed independently.
2Measurement precision
If multiple optical paths are used to detect displacement in multiple directions, then measurement accuracy is improved, but structural complexity increases
Solution Approach 1:
Both the first and second optical paths use identical components (illumination portion, imaging configuration, and detector portions), allowing the same optical structure to serve multiple measurement functions. This multi-functionality enables accurate two-dimensional displacement detection while avoiding the need for different specialized optical paths for each measurement direction.
Solution Approach 2:
The second optical path is intentionally inclined at an angle relative to the first optical path, creating an asymmetric configuration that enables sensitivity to displacement in different directions. This asymmetric arrangement of otherwise identical optical components allows the system to detect both X-direction and Z-direction displacements with comparable accuracy.
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
Enables the detection of two-dimensional displacement with a simpler structure, providing displacement signals indicative of movements along multiple directions, enhancing the accuracy and efficiency of displacement measurement.
Implementation Method 1
the scale grating defining a set of diffraction planes corresponding to a set of diffractive order angles corresponding to a plane wave perpendicularly incident onto the scale grating
Implementation Method 2
the imaging configuration comprises deflecting elements and a telecentric imaging portion; the telecentric imaging portion has an optical axis that is arranged along the third direction
Data Source
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AI summary
Disclosed is a displacement sensor configuration, comprising a scale grating disposed in a first direction; and a scale light imaging configuration which includes first and second optical paths and a detector including first and second detector portions. The imaging portion inputs a first scale light component output by the scale grating along the first optical path and transmits the first scale light component to the first detector portion, the imaging portion inputs a second scale light component output by the scale grating along the second optical path and transmits the second scale light component to the second detector portion, the first detector portion is configured to output a first displacement signal indicative of a displacement along the first direction, and the second detector portion is configured to output a second displacement signal indicative of a displacement along a second direction perpendicular to the first direction.