Voice Coil Motor Optical Unit for Endoscope Actuator Miniaturization
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Solution Overview
Problem
Existing endoscope technologies face challenges in miniaturizing and weight-reducing the actuator for moving lenses while maintaining accurate and efficient zoom functionality, particularly in the design of optical units with movable lens groups.
Innovation Solution
The optical unit incorporates a cylindrical fixing member, a movable member with a voice coil motor and magnets, and a rotation restricting member, allowing the movable member to slide along the central axis while preventing rotation, enhancing driving efficiency and enabling quick operation of the movable lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional actuator is used to move the movable lens group, then the zoom function can be achieved, but the actuator becomes large and heavy, reducing miniaturization efficiency
Solution Approach 1:
The patent replaces conventional mechanical actuators with a voice coil motor that utilizes electromagnetic force. The coil generates a magnetic field that interacts with the magnet attached to the movable lens group, directly producing linear motion without mechanical transmission components. This substitution eliminates complex mechanical structures, significantly reducing the actuator's size and weight while maintaining reliable zoom operation through precise electromagnetic control.
2Reliability
If the movable member is free to rotate, then manufacturing and assembly are simpler, but magnetic adsorption issues occur between the coil and magnet, reducing driving efficiency
Solution Approach 1:
The patent applies preliminary anti-action by introducing the rotation restricting member before magnetic adsorption can occur. This member prevents rotational movement of the movable lens group relative to the tube lens, ensuring that the magnet and coil remain in proper alignment. By preventing rotation in advance, the design eliminates magnetic adsorption issues that would otherwise reduce driving efficiency, while maintaining a relatively simple overall structure.
3Shape
If magnets are arranged radially on the movable member, then compact design is achieved, but rotation about the central axis causes misalignment and reduces precision
Solution Approach 1:
The rotation restricting member is positioned to prevent rotational movement before misalignment can occur. It contacts the movable lens group or its holder to constrain rotational degrees of freedom, ensuring that the magnet's radial arrangement maintains precise alignment with the coil throughout operation. This preliminary prevention of rotation preserves both the compact radial design and the required manufacturing precision.
4Weight of moving object
If the voice coil motor design is implemented, then miniaturization and weight reduction are achieved, but the movable member requires rotation restriction to prevent harmful magnetic adsorption
Solution Approach 1:
The rotation restricting member is extracted as a separate, dedicated component rather than being integrated into existing structures. This extraction allows for simple implementation - a standalone element that contacts the movable lens group to prevent rotation. By separating this function into its own component, the overall complexity remains low while achieving the weight reduction benefits of the voice coil motor design without suffering from magnetic adsorption issues.
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 improves driving efficiency, allows for accurate and miniaturized lens movement, and reduces the weight and size of the actuator, while preventing magnetic adsorption issues, thus enabling cost-effective and stable zoom operations.
Implementation Method 1
a voice coil motor including a coil arranged in the fixing member and magnets arranged on the movable member and magnetically polarized in a direction intersecting with the central axis, the voice coil motor being capable of moving the movable member relative to the fixing member along a direction of the central axis
Data Source
AI summary
An optical unit includes: a cylindrical fixing member configured to retain at least one of an object-side fixed lens group and an image-side fixed lens group; a cylindrical movable member configured to retain a movable lens group between the groups and arranged on a radial-direction inner side of the fixing member slidablly with respect to the fixing member, the cylindrical movable member having a same central axis as the cylindrical fixing member; a voice coil motor including: a coil arranged in the fixing member; and magnets arranged on the movable member and magnetically polarized in a direction intersecting with the central axis, the voice coil motor being capable of moving the movable member relative to the fixing member along a direction of the central axis; and a rotation restricting member configured to restrict rotation of the movable member about the central axis with respect to the fixing member.