Lens Driving Structure for Temperature-Stable Autofocus Calibration
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Solution Overview
Problem
Existing camera modules face challenges in suppressing defocusing caused by temperature variations and require complex calibration for auto-focusing feedback driving, especially in micro-scale, low-power applications like smartphone cameras.
Innovation Solution
A lens moving apparatus with a housing, bobbin, coil, magnets, and position sensors is designed, where the housing's structure and adhesive members help maintain consistent magnetic field detection across temperature changes, allowing for easy calibration and reduced defocusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a voice coil motor (VCM) is used in existing camera modules, then the motor can drive the lens for auto-focusing, but the technology is difficult to apply to micro-scale, low-power camera modules
Solution Approach 1:
The patent replaces the traditional voice coil motor (VCM) mechanical system with a magnetic field-based driving system. The apparatus uses a magnet assembly and coil assembly that generate magnetic fields to drive the lens barrel for auto-focusing, eliminating the need for complex mechanical VCM components. This substitution enables micro-scale camera modules to achieve auto-focusing functionality with reduced size and power consumption while maintaining reliability.
Solution Approach 2:
The patent changes the operating parameters of the driving system by using magnetic field intensity and coil current control instead of mechanical force. The control unit adjusts the current through the coil assembly to generate appropriate magnetic fields that move the lens barrel to desired positions, enabling precise auto-focusing in a compact configuration suitable for mobile devices.
2Volume of moving object
If the camera module is mounted in a small electronic product like a smartphone, then the device becomes compact and portable, but the camera module frequently receives shocks and undergoes fine shaking
Solution Approach 1:
The patent introduces a position sensor assembly as an intermediary between the lens barrel and the control system. The position sensor continuously monitors the lens barrel position and provides feedback to the control unit, which adjusts the magnetic field to compensate for shocks and vibrations. This feedback mechanism enables the camera module to maintain focus stability despite external disturbances in compact smartphone applications.
Solution Approach 2:
The patent implements a feedback control system where the position sensor detects lens barrel position and the control unit adjusts coil current accordingly. This closed-loop feedback mechanism allows real-time compensation for shocks and vibrations, maintaining auto-focusing accuracy in compact camera modules subjected to mobile device environmental conditions.
3Adaptability or versatility
If temperature varies in the ambient environment, then the camera module operates in different thermal conditions, but defocusing of the lens occurs
Solution Approach 1:
The patent uses the position sensor assembly to provide continuous feedback on lens barrel position under varying temperature conditions. The control unit adjusts the magnetic field generation through the coil assembly to compensate for thermal expansion or contraction effects, maintaining focus stability across different ambient temperatures in compact camera modules.
Solution Approach 2:
The patent dynamically adjusts magnetic field parameters through coil current control to compensate for temperature-induced changes in lens and housing dimensions. By changing the electrical parameters (current) rather than mechanical dimensions, the system maintains focus accuracy across temperature variations in portable devices.
4Measurement precision
If complex calibration is performed for auto-focusing feedback driving, then focus accuracy can be improved, but the calibration process becomes time-consuming and difficult
Solution Approach 1:
The patent enables the camera module to perform self-calibration through its feedback control system. The position sensor and control unit work together to automatically establish the relationship between coil current and lens barrel position without requiring complex external calibration equipment or procedures. This self-service calibration simplifies manufacturing while maintaining focus accuracy in compact camera modules.
Solution Approach 2:
The patent uses the feedback control system to automatically calibrate the auto-focusing mechanism during manufacturing or initial operation. The position sensor provides real-time position data that the control unit uses to establish the current-position relationship, enabling accurate focus control without complex manual calibration procedures in compact camera modules.
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 apparatus effectively suppresses lens defocusing due to temperature variations and facilitates easy calibration for auto-focusing feedback driving, improving image stability and focus accuracy in camera modules.
Implementation Method 1
a first position sensor disposed on the outer circumferential surface of the bobbin
Implementation Method 2
a first coil disposed on an outer circumferential surface of the bobbin; a first magnet disposed on the outer circumferential surface of the housing
Data Source
AI summary
An embodiment includes: a housing including an upper surface, a lower surface, an inner surface, and an outer surface located at the side opposite to the inner surface; a bobbin accommodated in the housing; a first coil disposed at an outer surface of the bobbin; a first magnet disposed at the outer surface of the housing; a second magnet disposed in the housing so as to be spaced apart from the first magnet; and a first position sensor disposed at the outer surface of the bobbin, wherein a first part of the housing is positioned between the second magnet and the inner surface of the housing.