Lens Structure Closed-Loop Control for High-Speed Focusing
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Solution Overview
Problem
Conventional security zoom lenses have low rotational speed of the drive motor, slow adjustment speed of the lens, and short service life of the drive mechanism due to their open-loop control systems, leading to blurred images and mechanical wear issues.
Innovation Solution
A lens structure with a closed-loop control system using a position detection device, such as a magnetic or optical grating sensor, and a drive mechanism with a motor and screw, allowing real-time position feedback and precise adjustment of the lens group, independent of mechanical precision and wear, enabling high-speed movement and accurate targeting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an open-loop control system using stepping motor and screw is used, then the device complexity is reduced, but the reliability decreases due to step loss and mechanical wear
Solution Approach 1:
The patent introduces a position detection device that provides real-time feedback on the lens group's actual position to the control device. The control device compares this actual position with the target position and adjusts the drive motor accordingly, forming a closed-loop control system that eliminates step loss and improves reliability without significantly increasing complexity
Solution Approach 2:
The patent replaces the purely mechanical open-loop control system with an integrated system that uses position detection (optical or magnetic field detection) to monitor lens group position. This substitution of mechanical feedback with optical/magnetic detection methods improves reliability while maintaining acceptable device complexity
2Productivity
If the drive motor operates at high rotational speed, then the productivity increases, but the reliability decreases due to step loss and mechanical wear
Solution Approach 1:
The position detection device provides real-time feedback on the lens group's actual position, allowing the control device to adjust the drive motor's operation dynamically. This enables the system to operate at high speeds while maintaining accuracy and reducing mechanical wear through precise control, thereby improving both productivity and reliability
Solution Approach 2:
The patent implements dynamic control where the drive motor's operation is continuously adjusted based on real-time position feedback. This dynamic adjustment allows the system to optimize speed and accuracy during operation, improving productivity while reducing mechanical wear and step loss that would occur with fixed low-speed operation
3Productivity
If the lens adjustment speed is increased, then the productivity increases, but the manufacturing precision requirements increase
Solution Approach 1:
The position detection device provides real-time feedback on the lens group's actual position, allowing the control device to make precise adjustments regardless of the adjustment speed. This feedback mechanism enables high-speed operation while maintaining manufacturing precision, as the system can compensate for any positioning errors dynamically during operation
Solution Approach 2:
The patent uses preliminary position detection and feedback to ensure accurate positioning before the lens group reaches the target position during high-speed adjustment. This preliminary action allows the system to maintain precision during rapid movement by continuously monitoring and adjusting the position in advance
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 closed-loop control system enhances the rotational speed of the drive motor, improves lens adjustment speed, and extends the service life of the drive mechanism by providing real-time feedback and precise positioning, reducing the impact of mechanical wear and step loss, resulting in clear imaging and prolonged product lifespan.
Implementation Method 1
The magnetic grating sensor includes a magnetic head and a magnetic grating. The magnetic grating is extended along the first direction, and the magnetic head is configured to be movable along the first direction and is fixedly connected to the lens group.
Implementation Method 2
The optical grating sensor includes a ruler grating and an indicator grating. The ruler grating is extended along the first direction, and the indicator grating is configured to be movable along the first direction and is fixedly connected to the lens group.
Data Source
AI summary
Disclosed are a lens structure, a photographic device and a focusing method of lens. The lens structure includes a lens barrel, a lens assembly, a drive mechanism, a position detection device and a control device. The lens barrel is extended along a first direction. The lens assembly includes a lens group configured to be movable along the first direction. The drive mechanism is fixedly connected to the lens group and configured to drive the lens group to move along the first direction. The position detection device configured to detect a position of the lens group in real time. The control device is electrically connected to the position detection device and the drive mechanism, and is configured to control the drive mechanism to work according to the position detection device to adjust the position of the lens group.