Projector Optical Alignment for Low-Distortion 3D Patterns
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical 3D imaging systems face issues with pattern distortions and optical propagation deviations due to imperfect alignment of VCSEL-array and refractive optical lens stack, leading to distorted dot patterns and inhomogeneous dot intensity distributions, which negatively impact 3D sensing solutions relying on grid-structured spot patterns.
Innovation Solution
A method for aligning optical components of a projector that includes emitter array alignment and transfer device alignment, utilizing a camera to evaluate intensity distributions and pattern centers, and adjusting orientations and positions to minimize distortions and ensure perpendicular alignment, thereby generating a projected pattern with minimal distortion and homogeneous spot distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If VCSEL-array and refractive optical lens stack are aligned using active alignment process with auxiliary camera and transparent target plate, then alignment can be performed, but pattern distortions and optical propagation deviations occur due to indirect determination of optical center point
Solution Approach 1:
The patent replaces the mechanical alignment process with an optical alignment method. Instead of using mechanical mounting and indirect optical center determination through transparent target plates, the invention uses optical beams from the VCSEL-array itself to directly determine the optical center position and align the lens stack, eliminating mechanical alignment errors and pattern distortions
Solution Approach 2:
The patent introduces optical beams as an intermediary to transfer alignment information. The optical beams serve as a mediator between the VCSEL-array and the lens stack, allowing precise determination of the optical center position and enabling accurate alignment without direct mechanical contact or indirect optical methods
2Reliability
If refractive optical lens stack is tilted to compensate for translational error, then optical propagation tilt can be corrected, but pattern distortion becomes more pronounced
Solution Approach 1:
The patent uses the optical center position determined from the VCSEL-array pattern as a copy or reference to align the lens stack. By copying the precise optical center location information and using it to position the lens stack, the method achieves accurate alignment without requiring compensatory tilting that would cause pattern distortion
Solution Approach 2:
Instead of tilting the lens stack to compensate for translational errors (the conventional approach), the patent inverts the approach by precisely positioning the lens stack based on the optical center position determined from the VCSEL-array, eliminating the need for compensatory tilting and its associated pattern distortions
3Ease of manufacture
If alignment is performed without direct optical center determination, then manufacturing process can be simplified, but distortion occurs in the dot pattern affecting 3D sensing performance
Solution Approach 1:
The patent replaces complex mechanical alignment procedures with a simplified optical method. The optical center position is directly determined using optical beams and pattern evaluation, eliminating the need for mechanical mounting adjustments and transparent target plates while achieving superior alignment precision and eliminating dot pattern distortions
Solution Approach 2:
The VCSEL-array performs self-alignment by using its own optical beams to determine the optical center position. The system uses itself as the alignment reference, eliminating the need for external auxiliary cameras and transparent target plates, thereby simplifying the manufacturing process while achieving high precision alignment
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 method reduces pattern distortions and improves homogeneity, enhancing the performance and robustness of 3D sensing systems by minimizing error sources and eliminating the need for active alignment during system production, resulting in higher projector yield and cost savings.
Implementation Method 1
Each of the VCSELs is configured for generating at least one light beam
Implementation Method 2
a refractive optical lens stack
Implementation Method 3
the reflected pattern is recorded and evaluated
Data Source
AI summary
Disclosed herein is a method for alignment of optical components of a projector for illuminating at least one object with at least one illumination pattern including a plurality of illumination features. The projector includes at least one array of emitters. Each of the emitters is configured for generating at least one light beam. The projector includes at least one transfer device configured for generating the illumination features from the light beams impinging on the transfer device.