Diffractive Optical Element Uniform Light Spot Distribution
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Solution Overview
Problem
Diffractive optical elements used in three-dimensional measuring devices generate speckle patterns with light spots of varying intensity, leading to density inhomogeneity on the projection plane, resulting in regions without light spots and inaccurate measurements due to degradation in resolution.
Innovation Solution
A diffractive optical element with concaves and convexes that diffract light in two dimensions, ensuring an average distance between light spots within a specific range, thereby avoiding large regions without light spots and achieving uniform light spot distribution, and a measuring device employing this element for accurate three-dimensional measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a speckle pattern is generated by a diffractive optical element, then light spots are formed on the projection plane, but density inhomogeneity of light spots arises and large regions without light spots are generated
Solution Approach 1:
The diffractive optical element is designed with locally varied concave and convex structures where each local region has specific depth and shape characteristics. The concaves and convexes have different depths (first depth and second depth) and shapes to control the phase of diffracted light, creating uniform light spot distribution across different regions of the projection plane
Solution Approach 2:
The invention changes the physical parameters of the diffractive optical element by controlling the depth and shape of concaves and convexes. By varying the depth (first depth for convexes, second depth for concaves) and shape parameters, the phase distribution of diffracted light is controlled to achieve uniform light spot density across the projection plane
2Measurement precision
If light spots are projected onto the measurement object, then three-dimensional measurement is performed, but measurement accuracy degrades in regions without light spots
Solution Approach 1:
The diffractive optical element creates locally optimized light spot patterns where each region of the projection plane receives appropriate light spots. This ensures that every local region of the measurement object is illuminated with sufficient light spots for accurate three-dimensional measurement, eliminating measurement gaps
3Speed
If conventional diffractive optical elements are used, then light diffraction is achieved, but large regions without light spots are generated causing resolution degradation
Solution Approach 1:
The invention optimizes the spatial parameters of the diffractive optical element by controlling the depth and shape of concaves and convexes. This parameter optimization ensures efficient light diffraction while simultaneously achieving uniform light spot distribution, preventing resolution degradation in the measurement system
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 suppresses light spot density inhomogeneity, allowing for accurate and high-resolution three-dimensional measurements by ensuring a uniform distribution of light spots across the projection area, enhancing the measurement sensitivity and reducing the size of the measurement optical system.
Implementation Method 1
a diffractive optical element having concaves and convexes and diffracting incident light in two dimensions so as to generate diffracted light
Implementation Method 2
the diffractive optical element has a reflecting layer composed of a material for reflecting light and the diffracted light is reflected light reflected by the reflecting layer
Data Source
AI summary
To provide a diffractive optical element and a measuring device capable of generating light spots of dispersive type. The problem is resolved by providing a diffractive optical element having concaves and convexes and diffracting incident light in two dimensions so as to generate diffracted light, wherein when the number of a part of light spots formed by the diffracted light is denoted by n, an average distance W to the nearest neighbor in the light spots normalized by an area of a region onto which the light spots are projected falls within a range of 1/(2×n1/2)<W<1/(n1/2).