Endoscope Optical Unit Voice Coil Motor Position Detection
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Solution Overview
Problem
Existing optical units in endoscopes face challenges in smoothly moving the movable lens portion relative to the fixed portion for zoom and focusing functions, often resulting in instability and reduced precision due to friction and leakage magnetic fields affecting detection accuracy.
Innovation Solution
The optical unit incorporates a voice coil motor with a coil and magnet arrangement, along with a biasing part and sliders, to move the movable lens portion along the optical axis, utilizing a cylindrical fixed portion with rail portions and a magnetic detector for precise position detection, reducing friction and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voice coil motor is used to move the movable lens portion for zoom and focusing functions, then the lens can be moved along the optical axis, but friction and leakage magnetic fields cause instability and reduced detection precision
Solution Approach 1:
A magnetic detector is introduced as an intermediary component to detect the position of the movable lens portion. The magnetic detector uses a magnetic field instead of direct mechanical contact, eliminating friction and leakage magnetic fields that affect stability and detection precision. The magnetic detector includes a detection element that senses the position based on magnetic field changes, providing stable and precise position feedback without mechanical interference.
2Ease of operation
If the movable lens portion is moved relative to the fixed portion for zoom and focusing, then optical adjustment is achieved, but friction affects movement smoothness and precision
Solution Approach 1:
The patent replaces the mechanical contact-based position detection system with a magnetic field-based detection system. The magnetic detector uses electromagnetic fields to sense position without mechanical contact between the movable lens portion and the fixed portion. This substitution eliminates friction that would otherwise affect movement smoothness and precision, allowing the movable lens to move freely while maintaining accurate position detection.
3Force
If a biasing part is added to generate biasing force for the movable portion, then the lens can be pushed toward the fixed portion, but device complexity increases
Solution Approach 1:
The biasing part is integrated into the existing voice coil motor assembly rather than being added as a separate external component. The magnetic detector and biasing part share the same structural space within the optical unit, with the biasing part positioned to exert force on the movable lens portion while the magnetic detector detects its position. This merging approach provides the necessary biasing force while minimizing increases in overall device complexity.
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 allows for smooth and precise movement of the movable lens, improving zoom and focusing capabilities while minimizing friction and leakage magnetic field influence, leading to enhanced optical unit performance and reduced part count for cost-effectiveness.
Implementation Method 1
a driver that includes a coil and a magnet, the driver being configured to move the movable portion in a direction of an optical axis of the lens relative to the fixed portion
Implementation Method 2
utilizing a cylindrical fixed portion with rail portions and a magnetic detector for precise position detection
Data Source
AI summary
An optical unit includes: a fixed portion; a movable portion arranged movably inside the fixed portion; a first slider arranged between the fixed portion and the movable portion, the first slider being configured to slide with a movement of the movable portion; a second slider arranged between the fixed portion and the movable portion, and at a position different from a position of the first slider, the second slider being configured to slide with the movement of the movable portion; a driver that includes a coil and a magnet; and a biasing part that is arranged outside the movable portion, the biasing part being configured to cause the magnet to generate a biasing force to push the movable portion toward the fixed portion.