Intraoral Scanner Lens Positioning for Precise 3D Dental Scans
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Solution Overview
Problem
In dental prosthesis and orthodontic procedures, obtaining accurate 3D models of the dental site is crucial for designing optimal prosthetics and appliances, but existing methods often face challenges with incomplete or undefined models, leading to suboptimal design and potential collisions or improper fit.
Innovation Solution
A positioning system using a linear actuator with a permanent magnet and conductive winding, coupled with a linear-motion bearing, allows precise translational movement of a lens within an optical device, enabling accurate 3D scanning by maintaining the lens axis centered and preventing movement normal to it, thus improving measurement accuracy and model completeness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the lens is allowed to move freely during scanning, then the scanning area can be adjusted, but the lens axis may deviate from the centered position, reducing measurement precision
Solution Approach 1:
The lens is mounted on a movable platform that can dynamically adjust its position along the optical axis to accommodate different scanning areas, while the linear-motion bearing dynamically maintains the lens axis centered during movement, resolving the contradiction between adaptability and precision
Solution Approach 2:
The linear-motion bearing acts as an intermediary mechanism between the movable lens platform and the fixed housing, enabling positional adjustment while constraining lateral deviations, thus maintaining measurement precision during scanning area changes
2Measurement precision
If a fixed lens position is used, then measurement precision is maintained, but the scanning area cannot be adjusted for different dental procedures
Solution Approach 1:
The lens positioning system transitions from a fixed to a dynamically adjustable configuration, where the lens can be moved along the optical axis using a linear actuator while the linear-motion bearing ensures the lens axis remains centered, achieving both precision and adaptability
3Measurement precision
If the lens is constrained to prevent movement, then positioning accuracy is maintained, but the ability to adjust focus and scanning parameters is limited
Solution Approach 1:
The lens positioning system is segmented into independent degrees of freedom: longitudinal movement along the optical axis for focus adjustment is permitted, while lateral movements are constrained by the linear-motion bearing, achieving both precision and operational flexibility
Solution Approach 2:
The system dynamically controls lens movement by allowing longitudinal displacement for focus adjustment while maintaining lateral constraint through the linear-motion bearing, resolving the contradiction between positioning accuracy and focus adjustment capability
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 system enhances the accuracy of 3D scanning by maintaining the lens axis centered and preventing movement normal to it, leading to more complete and accurate 3D models, which in turn improves the design and fit of dental prosthetics and orthodontic appliances.
Implementation Method 1
The inner element includes a permanent magnet and the outer element includes a conductive winding. A current driven through the conductive winding generates a magnetic field that interacts with the magnetic field generated by the permanent magnet to produce a force that moves the inner element in the longitudinal direction
Data Source
AI summary
A scanner includes a lens assembly comprising a lens having a lens axis and a positioning system to adjust a focal plane of the lens assembly. The positioning system includes an outer element, an inner element coupled to the lens assembly, and a linear-motion bearing that couples the inner element to the outer element.