Projector Assembly Using Positioning Protector for 3D Sensing
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Solution Overview
Problem
Standard PCB assembly technologies, such as Surface-Mount Technology, fail to provide the necessary accuracy for the precise orientation of projector modules in 3D sensing systems, leading to periodic patterns along epi-polar lines due to insufficient placement precision.
Innovation Solution
A method utilizing a protector or jig to accurately position projectors based on their optical positions rather than their pad shape, combined with a reflow process, ensures alignment accuracy of less than ±0.5°, using flexible positioning arms and a plastic protector that withstands reflow temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard PCB assembly technologies (SMT method) are used to mount projector modules, then the manufacturing process is simple and efficient, but the placement accuracy is insufficient (cannot guarantee required angle accuracy)
Solution Approach 1:
The patent introduces a positioning element as an intermediary component between the PCB and the projector module. This positioning element has a first shape that interfaces with the PCB pad and a second shape that interfaces with the projector module, enabling precise optical alignment while maintaining compatibility with standard PCB assembly processes. The positioning element mediates the interface between the standardized PCB mounting system and the precision-optical requirements of the projector.
Solution Approach 2:
The positioning element is pre-designed with specific geometric shapes tailored to the optical component's requirements before the assembly process. The first shape is customized to fit the PCB pad configuration, and the second shape is customized to match the projector module's mounting interface, enabling accurate placement without requiring complex real-time adjustment during assembly.
2Measurement precision
If standard SMT assembly is used for mounting projectors, then large-scale manufacturing is efficient, but the angle accuracy required for non-repetitive pattern projection cannot be achieved
Solution Approach 1:
The positioning element serves as a precision intermediary that translates the relatively coarse PCB pad geometry into the precise angular orientation required by the projector module. By incorporating the positioning element into the assembly process, high angle accuracy can be achieved without sacrificing manufacturing efficiency, as the positioning element can be integrated into standard SMT workflows.
Solution Approach 2:
The positioning element enables parameter transformation by converting the positional information from the PCB pad (first shape) into the precise angular orientation parameter required by the projector module (second shape). This parameter change allows the system to achieve high measurement precision while maintaining compatibility with high-volume manufacturing processes.
Data Source
AI summary
A method is provided for assembling a 3D sensing apparatus that comprises at least two projectors, wherein the assembling of the apparatus is carried out by ensuring that a pattern formed from a combination of images projected by each of the at least two projectors, is not formed along an epi-polar line or part thereof more than once. The method comprises the steps of: placing the at least two projectors at initial approximate physical positions within the 3D sensing apparatus; and, placing one or more projectors' protectors on top of the at least two projectors, thereby changing the projectors initial positions and automatically positioning them accurately in their pre-defined position and orientation by using the one or more projectors' protectors.