Diffraction Optical Element Uniform Light Distribution
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Solution Overview
Problem
Existing diffraction optical elements face challenges in generating a desired light pattern with uniform light quantity distribution due to issues with 0th-order diffracted light, particularly when divergent light is incident with a large divergence angle, leading to overlap and difficulty in processing and design limitations.
Innovation Solution
A diffraction optical element combining divergence angle converting and light beam splitting functions to adjust the divergence angle of incident light and split it into multiple beams with different divergence angles, reducing the impact of 0th-order diffracted light and allowing for uniform light quantity distribution and desired light patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If parallel light is incident on a diffraction optical element, then light spots can be generated, but 0th-order diffracted light with large light quantity is emitted making other light spots unrecognizable
Solution Approach 1:
The patent segments the incident light beam into multiple diffracted light beams with different propagation directions by using a diffraction optical element with a specific phase distribution. This segmentation separates the 0th-order diffracted light from other diffracted orders, allowing individual control and recognition of each light spot by adjusting detection sensitivity for different directional ranges.
2Object-generated harmful factors
If divergent light with large divergence angle is incident on a diffraction optical element, then 0th-order diffracted light optical density is reduced, but other diffracted lights also become divergent causing overlap and inability to generate desired light pattern
Solution Approach 1:
The patent applies local quality by creating a phase distribution that varies at different spatial locations across the diffraction optical element. The phase modulation is designed such that different regions of the element produce diffracted lights with different divergence characteristics, allowing the 0th-order light to have reduced optical density while other diffracted lights maintain appropriate convergence to form the desired light pattern without overlap.
3Object-generated harmful factors
If multiple diffraction optical elements are stacked to suppress 0th-order diffracted light, then 0th-order light is reduced, but alignment problems and pattern generation limitations occur
Solution Approach 1:
The patent integrates multiple functions into a single diffraction optical element by designing a phase distribution that simultaneously achieves 0th-order light suppression and desired light pattern generation. The element performs both the function of reducing 0th-order diffracted light optical density and the function of generating specific light patterns with proper divergence control, eliminating the need for multiple stacked elements and their associated alignment complexities.
4Measurement precision
If gain is adjusted higher to recognize weaker light spots, then light spots become recognizable, but blur occurs around 0th-order light spot
Solution Approach 1:
The patent performs preliminary action by pre-separating the 0th-order diffracted light from other diffracted light spots through directional segmentation before detection. By designing the phase distribution to emit 0th-order light in a specific direction distinct from other light spots, the system enables clear recognition of weaker light spots at appropriate gain levels without blur, as the 0th-order light does not overlap with other spots even when gain is adjusted.
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 generation of light patterns with uniform light quantity distribution on a detection surface, facilitates easy processing even with large divergence angles, and allows for overall irradiation with adjustable light intensity, enhancing design flexibility and reducing stray light.
Implementation Method 1
a divergence angle converting function of converting a divergence angle of incident light based on diffraction effect and a light beam splitting function of splitting an incident light beam into a plurality of light beams based on diffraction effect
Data Source
AI summary
To make it possible to emit a light pattern with a uniform light quantity within a detection surface in spite of 0th-order diffracted light included therein or to emit a light pattern for overall irradiation with a uniform light quantity distribution, without limiting a degree of freedom for design of the emitted light pattern.In a diffraction optical element according to the invention, a divergence angle converting function that is a function of converting the divergence angle of incident light due to diffraction effect and a light beam splitting function that is a function of splitting an incident light beam into a plurality of light beams due to diffraction effect are combined so that incident light as divergent light is split into a plurality of diffracted lights with different divergence angles from the divergence angle of the incident light and the diffracted lights is emitted.