3D Optical Sensor Assembly for Thermal Expansion Isolation
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Solution Overview
Problem
3D optical sensing devices face instability due to thermal expansion, leading to mechanical distortion and performance degradation, particularly in stereo 3D sensing modules where precise alignment of optical elements is crucial.
Innovation Solution
The solution involves an electro-optical module (EOM) with a combination of a metal stiffener, isolating material, and flexible cables to maintain the relative position of optical components, using a junction PCB with a single hard connection and soft connections to manage thermal expansion and external forces, ensuring structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the camera modules are firmly connected to the enclosure using multiple mechanical anchors, then the structural stability is improved, but the thermal expansion forces cause deformation of the enclosure and stiffener, leading to misalignment of optical elements
Solution Approach 1:
The patent extracts the harmful constraint by reducing the number of mechanical anchors from multiple to a single anchor point. This removes the source of deformation caused by thermal expansion forces while maintaining the necessary structural support for the camera modules.
Solution Approach 2:
The patent introduces a flexible membrane as an isolating material between the enclosure and the camera modules. This membrane allows thermal expansion to occur without transmitting deformation forces to the optical elements, while still providing isolation and support.
2Stability of the object's composition
If the PCB is fastened to the enclosure with multiple screws, then the mechanical stability is improved, but the thermal expansion of the PCB pushes against the anchors, causing deformation of the mechanical structure
Solution Approach 1:
The patent removes the harmful multiple-screw anchoring system and replaces it with a single anchor point. This eliminates the mechanism by which PCB thermal expansion causes structural deformation, while maintaining adequate mechanical support.
Solution Approach 2:
The patent changes the mechanical connection parameters from rigid multiple-point attachment to a single-point attachment with flexible isolation. This allows the system to accommodate thermal expansion without transmitting deforming forces to the enclosure structure.
3Strength
If the metal stiffener is used to maintain dimensional stability, then the structural rigidity is improved, but the stress from manufacturing processes causes slow deformation over time, leading to performance deterioration
Solution Approach 1:
The patent removes the metal stiffener component that causes long-term reliability problems. By eliminating this element, the system avoids the stress-related deformation issues that arise from manufacturing processes like CNC machining or injection molding.
Solution Approach 2:
The patent replaces the metal stiffener with a composite structure using isolating materials and flexible membranes. This composite approach provides the necessary structural support while avoiding the stress accumulation and deformation issues inherent in rigid metal components.
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 solution effectively maintains the relative position of optical elements, preventing deformation and ensuring consistent performance over time and temperature changes, thereby enhancing the stability and accuracy of 3D sensing.
Implementation Method 1
Thermal expansion e.g., by heat generated by the module or heat generated outside the module, might lead to mechanical distortion which leads to tiny movements of the optical elements
Implementation Method 2
These thermal expansion forces might be extremely high. This in turn would lead to deformation of the mechanical structure and consequently degrade the performance of the electro optical module
Data Source
AI summary
An electro-optical (EOM) included within an enclosure is provided. The EOM comprises at least two camera modules, and configured to determine depth of a target by using a block matching algorithm operative to match pixels derived from an image captured by one of the camera modules with pixels derived from an image captured by another of the two camera modules. The EOM is characterized in that it comprises: a first isolating material located between the EOM and its enclosure, and configured to prevent structural forces from being developed due to deformation of the EOM enclosure; a main processor baseboard PCB to which each of the camera modules is connected; and one or more flat cables connecting the EOM enclosure with the main processor baseboard PCB, wherein the one or more flat cables are placed in an “s” shape within the EOM enclosure.