Diffractive Optical Element Uniform Light Spot Distribution
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Solution Overview
Problem
Diffractive optical elements used in coordinate measuring apparatuses face challenges in achieving uniform light spot density, leading to pincushion distortion and reduced detection sensitivity due to large diffraction angles, which affect the accuracy of three-dimensional measurements.
Innovation Solution
A diffractive optical element comprising two diffractive optical parts with specific diffraction angles and light spot distributions, where the first part generates diffracted lights that are input to the second part to create a uniform light spot density across a projection region, suppressing pincushion distortion and enhancing measurement sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a diffractive optical element is used to project light over a wide range with a large diffraction angle, then the light distribution range is improved, but the luminous energy of zero order diffracted light becomes large causing blurring and image deterioration
Solution Approach 1:
The patent divides the diffractive optical element into multiple diffractive patterns with different diffraction angles. By segmenting the diffraction function across multiple patterns, the system achieves wide light distribution while controlling zero-order light energy through the combined effect of multiple segmented diffraction zones.
2Area of stationary object
If the diffraction angle is increased to distribute light over a wide range, then the coverage area is improved, but the interval between light spots becomes longer reducing detection sensitivity
Solution Approach 1:
The patent employs diffractive optical patterns with asymmetric diffraction angle distributions. By using different diffraction angles in different regions or directions, the system optimizes light spot density distribution to maintain high detection sensitivity across the entire projection range while achieving wide area coverage.
3Measurement precision
If two diffractive optical elements are used to reduce zero order diffracted light, then the luminous energy distribution is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple diffractive optical patterns into a single integrated diffractive optical element. By merging multiple diffraction functions into one component, the system achieves improved luminous energy distribution and zero-order light suppression without increasing device complexity, as all diffractive patterns are fabricated together in a single element.
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 ensures a uniform distribution of light spots, improving the accuracy and sensitivity of three-dimensional measurements by reducing luminous energy fluctuations and pincushion distortion, thereby enhancing the precision of the measuring apparatus.
Implementation Method 1
a diffractive optical element that diffracts at least a part of incident light
Implementation Method 2
the diffracted light generated from the diffractive optical element is emitted at a predetermined angle from the diffractive optical element according to a diffraction grating formula
Data Source
AI summary
A diffractive optical element includes first and second diffractive optical parts to generate diffracted lights two-dimensionally with respect to incident light. The diffracted lights generated by inputting the incident light to the first diffractive optical part are input to the second diffractive optical part in order to generate the diffracted lights from the second diffractive optical part, wherein θ1≧θ2 and k1≧k2 stand or, θ1≦θ2 and k1≦k2 stand among θ1 and θ2 denote diffraction angles of the first and second diffractive optical parts, and k1 and k2 denote numbers of light spots of the diffracted lights generated by the first and second diffractive optical parts.