Zoom Lens Assembly with Endpoint Locking for VCM Collision Prevention
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Solution Overview
Problem
Lenses driven by a voice coil motor (VCM) are prone to breaking and deformation due to collisions when the zoom or focus group completes its operation and is not properly locked, leading to potential damage.
Innovation Solution
A zoom lens assembly with a fixing cartridge, mobile group, driving mechanism, position detection device, limiting mechanism, and control device, which includes a limiting portion that switches between locking and unlocking positions based on real-time position detection, using electromagnetic force for movement and closed-loop control to prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voice coil motor (VCM) is used to drive the zoom or focus group, then the lens can achieve precise movement and focusing, but the lens is prone to breaking and deformation due to collisions when the zoom or focus group completes its operation
Solution Approach 1:
The limiting mechanism is activated in advance to lock the mobile group at the endpoint of its movement stroke before any collision can occur. The control device receives position feedback and proactively engages the limiting portion to prevent the mobile group from exceeding its safe travel range, thereby eliminating the harmful collision effect before it can damage the lens.
Solution Approach 2:
The limiting mechanism acts as an intermediary safety device between the voice coil motor and the mobile group. It mediates the motion control by introducing a mechanical constraint that prevents the mobile group from moving beyond its designated range, thus protecting the lens from collision damage while allowing precise movement within the safe zone.
2Reliability
If a limiting mechanism is added to prevent collisions, then lens damage is prevented, but device complexity increases
Solution Approach 1:
The limiting mechanism is designed to be self-actuating through the interaction of spring elastic components and shape memory alloy. The shape memory alloy wire automatically changes its shape in response to temperature changes or electrical stimulation, causing the limiting portion to rotate and engage or disengage the locking groove without requiring complex external control systems, thereby reducing overall device complexity.
Solution Approach 2:
The patent replaces complex mechanical control systems with shape memory alloy technology. The shape memory alloy wire can change its shape in response to electrical or thermal stimuli, automatically controlling the limiting portion's position without requiring complex mechanical linkages or multiple actuators, thus simplifying the overall structure while maintaining reliable collision prevention.
3Measurement precision
If real-time position detection and closed-loop control are implemented, then precise positioning is achieved, but device complexity and cost increase
Solution Approach 1:
The control device receives real-time position feedback from position detection means (such as Hall sensors or encoders) and adjusts the voice coil motor's operation accordingly. This closed-loop feedback system ensures the mobile group reaches the precise target position and stops accurately, enabling the limiting mechanism to engage at the correct endpoint while maintaining simple and intuitive control logic.
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
Effectively prevents lens damage by ensuring precise positioning and locking of the mobile group, reducing the risk of collisions and deformation, even in the event of sudden power loss or impact.
Implementation Method 1
driving mechanism, configured to drive the mobile group to move forward and backward
Implementation Method 2
position detection device, configured to detect a relative position of the mobile group and the fixing cartridge in real time
Data Source
AI summary
Disclosed is a zoom lens assembly. The zoom lens assembly includes a fixing cartridge, at least one mobile group, a driving mechanism, a position detection device, a limiting mechanism, and a control device. The mobile group has a self-locking position during a movable stroke. The driving mechanism is configured to drive the mobile group to move forward and backward. The position detection device is configured to detect a relative position of the mobile group and the fixing cartridge in real time. The limiting mechanism includes a limiting portion provided movably. The limiting portion has a locking position and an unlocking position during a movable stroke, in the locking position, the limiting portion is configured to limit the mobile group to the self-locking position, and in the unlocking position, the limiting portion is configured to avoid the mobile group.