Lens Array Pitch Divergence for Diffractive Optical Element Spot Overlap
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Solution Overview
Problem
In structured light systems, reducing the pitch between emitters to minimize cost and size leads to overlapping spots in the light pattern, and zero-order beamlets concentrate at a single spot, posing eye safety concerns.
Innovation Solution
An optical system with a lens array pitch larger than the emitter array pitch causes collimated beams to diverge, allowing the diffractive optical element to distribute them into zero-order beamlets that spread, preventing spot overlap and ensuring uniform power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pitch between emitters is reduced to minimize cost and size, then the emitter array size is reduced, but spot overlap occurs in the light pattern
Solution Approach 1:
A lens array is introduced as an intermediary component between the emitter array and the diffractive optical element. The lens array with a larger pitch than the emitter array acts as a mediator that redistributes the beams, preventing spot overlap while maintaining a compact emitter array design.
Solution Approach 2:
The system transitions from a direct one-to-one mapping between emitters and output spots to a many-to-many relationship by introducing the lens array dimension. This additional optical dimension allows multiple emitters to map to different output locations, preventing overlap even when emitters are closely spaced.
2Area of stationary object
If the pitch between emitters is reduced to minimize cost and size, then the emitter array size is reduced, but zero-order beamlets concentrate at a single spot causing eye safety concerns
Solution Approach 1:
The lens array serves as an intermediary that prevents zero-order beamlets from concentrating at a single spot. By redistributing the beams through its larger pitch structure, it disperses the energy across multiple locations, thereby mitigating eye safety risks while maintaining a compact emitter array.
Solution Approach 2:
The lens array segments the zero-order beamlets from concentrating at a single point. The larger pitch between lenses creates multiple distinct beam paths that separate the energy distribution, preventing concentration and reducing eye safety concerns.
3Manufacturing precision
If the pitch between lenses is made larger than the pitch between emitters to prevent spot overlap, then beam divergence occurs, but this allows uniform power distribution
Solution Approach 1:
The system changes the critical parameter from emitter pitch to lens pitch, making the lens pitch larger than the emitter pitch. This parameter change fundamentally alters the beam geometry, creating divergence that prevents spot overlap and enables uniform power distribution across the output pattern.
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
This design reduces emitter array size and cost while preventing spot overlap and ensuring uniform power distribution, addressing both cost and safety concerns.
Implementation Method 1
collimate each of the plurality of beams of light
Implementation Method 2
collimate and direct each of the plurality of beams of light
Implementation Method 3
the diffractive optical element diffracts a given beam of light such that diffracted orders of the given beam are transmitted by the diffractive optical element at different angles
Implementation Method 4
a pitch between lenses of the lens array is larger than a pitch between emitters of the emitter array in order to cause each of the plurality of beams of light to be directed such that the plurality of beams of light diverge after exiting the lens array
Data Source
AI summary
An optical system may include an emitter array to emit a plurality of beams of light, and a lens array. The lens array may be arranged to collimate and direct each of the plurality of beams of light. A pitch between lenses of the lens array may be larger than a pitch between emitters of the emitter array in order to cause the plurality of beams of light to be directed such that they diverge after exiting the lens array. The optical system may include a diffractive optical element to distribute each of the plurality of beams of light into a plurality of beamlets in association with creating a light pattern. The divergence of each of the plurality of beams of light may cause a plurality of zero-order beamlets, each corresponding to one of the plurality of beams of light, to diverge after exiting the diffractive optical element.