Microlens Array Structured Light Pattern Generation
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Solution Overview
Problem
Existing structured light systems face challenges in producing high contrast patterns over a large range of distances with minimal components, high intensity, and loose alignment tolerances while maintaining manufacturability and yield.
Innovation Solution
The proposed apparatus includes a microlens array and an illumination unit where the lens pitch, distance, and wavelength are optimized such that P^2 = 2LD/N, with N being an integer, allowing for high contrast structured light production without the need for precise alignment and complex optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional structured light systems use multiple complex optical components and precise alignment, then pattern quality can be improved, but device complexity and alignment difficulty increase
Solution Approach 1:
The patent extracts and eliminates unnecessary optical components from conventional structured light systems. By using a single lens array to perform both beam shaping and pattern projection, the system removes intermediate optical elements like beam expanders, spatial light modulators, and multiple relay lenses, thereby reducing device complexity while maintaining pattern quality
Solution Approach 2:
The single lens array serves multiple functions simultaneously: it acts as a beam shaper to collimate light from the source, a pattern generator to create the structured illumination, and a projection element to deliver the pattern to the target. This multi-functionality reduces the number of components needed while achieving the desired pattern contrast
2Manufacturing precision
If conventional systems require precise alignment of optical components, then pattern accuracy can be improved, but ease of manufacture and alignment tolerance worsen
Solution Approach 1:
The lens array is designed to self-align with the light source through its optical properties. The lens array automatically focuses and shapes the light from the source without requiring precise manual alignment, as the optical geometry inherently guides the light paths. This self-aligning behavior significantly relaxes assembly tolerances and simplifies manufacturing
Solution Approach 2:
The patent optimizes specific parameters of the lens array (focal length, lens diameter, spacing between lenses) to achieve a configuration where the system becomes insensitive to alignment variations. By carefully selecting these parameters, the design ensures that small deviations in assembly do not significantly affect pattern quality, thereby improving ease of manufacture
3Power
If the apparatus is designed for high intensity structured light, then illumination capability is improved, but contrast over large distance ranges may deteriorate
Solution Approach 1:
The lens array is designed to produce a dynamic light distribution that maintains pattern contrast across varying distances. The optical geometry creates a light field that adapts to different observation planes, ensuring that the structured pattern remains distinguishable whether the target is close or far from the apparatus, while maintaining high overall intensity
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 configuration achieves high contrast patterns over a wide range of distances with reduced component complexity and relaxed alignment requirements, enhancing manufacturability and yield while maintaining high intensity.
Implementation Method 1
a microlens array consisting of a plurality of lenses, one lens for each VCSEL. The micro-lens array serves to focus and direct the beams from the VCSEL array
Implementation Method 2
The present inventors have discovered that for certain selections of a lens pitch P of a microlens array (MLA) and of a distance D of the MLA to a light source illuminating the MLA... a contrast in structured light thereby produced is particularly strong
Data Source
AI summary
An apparatus for producing structured light comprises a first optical arrangement which comprises a microlens array (L1) comprising a multitude of transmissive or reflective microlenses (2) which are regularly arranged at a lens pitch P and an illumination unit for illuminating the microlens array. The illumination unit comprises an array (S1) of light sources (1) for emitting light of a wavelength L each and having an aperture each, wherein the apertures are located in a common emission plane which is located at a distance D from the microlens array. For the lens pitch P, the distance D and the wavelength L, the following equation applies P2=2LD/N, wherein N is an integer with N≥1. High-contrast high-intensity light patterns can be produced. Devices comprising such apparatuses can be used for depth mapping.