Mixing Grating Optical Position Sensor Compact Design
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Solution Overview
Problem
Existing optical position measuring devices are bulky and require complex adjustments due to the need for separate combining and focusing elements, which increases the structural size and component count, limiting their compactness and ease of use.
Innovation Solution
A compact optical position measuring device that integrates the phase-shifting and focusing functions into a single mixing grating, reducing the number of components and simplifying adjustments, while maintaining the necessary optical properties through a diffractive component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate combining element and focusing element are used, then the optical functions are properly fulfilled, but the device size and component count increase
Solution Approach 1:
The patent combines the combining element and focusing element into a single diffractive component (grating) that performs both functions simultaneously. The grating structure is designed to both combine the interferential beams and focus them onto the detector elements, eliminating the need for separate optical components and reducing overall device complexity.
Solution Approach 2:
The diffractive component is designed as a multi-functional element that serves multiple purposes: it acts as a combining element for interferential beams, a focusing element for directing beams to detectors, and a diffractive element for beam manipulation. This universal component approach reduces the total number of parts while maintaining all necessary optical functions.
2Manufacturing precision
If separate combining element and focusing element are used, then the optical paths are properly controlled, but the structural volume increases
Solution Approach 1:
By merging the combining and focusing functions into a single grating component, the patent significantly reduces the structural volume required for the optical system. The integrated design eliminates the space needed for multiple separate elements and their associated mounting structures, resulting in a more compact device.
Solution Approach 2:
The patent replaces a mechanical optical system (requiring multiple physical components with precise mechanical alignment) with a diffractive optical system where the grating structure inherently controls beam paths through its periodic pattern. This substitution reduces mechanical complexity and device volume while maintaining precise optical control.
3Reliability
If more components are used for combining and focusing, then the optical performance is maintained, but the adjustment complexity increases
Solution Approach 1:
The integration of combining and focusing functions into a single grating component dramatically simplifies adjustment procedures. Instead of requiring separate alignment of multiple optical elements, the patent achieves proper optical performance through the inherent design of the grating structure, reducing assembly and adjustment complexity.
Solution Approach 2:
The diffractive grating is designed to automatically perform both combining and focusing functions through its fixed periodic structure, eliminating the need for manual adjustment of multiple components. The system is self-aligning in the sense that the grating's geometric structure inherently provides the required optical functions without requiring complex mechanical adjustment mechanisms.
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 enables a more compact and cost-effective position measuring device with reduced mass and complexity, capable of detecting relative movements in various directions with improved sensitivity and reduced signal noise.
Implementation Method 1
at least three pairs of interfering partial beams of rays then propagate further in different spatial directions and are focused on one detector element each with the aid of a focusing element
Implementation Method 2
interferential determination of the relative distance between two objects that can be moved relative to one another
Data Source
Figure 1a~1b
Figure 1a'
Figure 2a~2b
AI summary
The present invention relates to an optical position measuring device for the interference-based determination of the relative distance between two objects that are movable relative to each other along at least one measuring direction. In this device, a beam emitted by a light source is split into at least two partial beams, which then strike one or more gratings along separate beam paths and thereby undergo distance-dependent phase shifts. The partial beams are superimposed at a mixing grating, and subsequently, at least three pairs of interfering partial beams propagate in different spatial directions. The mixing grating further focuses each pair of interfering partial beams onto a detector element, so that at least three position-dependent, phase-shifted incremental signals can be detected by the detector elements (Fig. 1a).