Lens Driver Layout for Fast Focus and Heat-Safe Position Sensing
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Solution Overview
Problem
Existing lens driving apparatuses for portable electronic devices face challenges in achieving a compact size while maintaining high sensitivity and fast focus functionality, with position sensor accuracy often being compromised by high temperatures during the assembly process.
Innovation Solution
A lens driving apparatus comprising a holder, metal cover, carrier, sensing magnet, position sensor, coil, and driving magnet, with strategically arranged metal terminals and a compact design that includes a printed circuit board and leaf springs to enhance assembly efficiency and reduce temperature effects on the position sensor, allowing for precise displacement detection and fast focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a VCM with multiple essential elements is used for auto-focusing, then the focus function is achieved, but the lens assembly size increases
Solution Approach 1:
The patent combines multiple essential elements (driving magnet, sensing magnet, position sensor, coil) into a compact integrated structure where the driving magnet and sensing magnet are positioned on opposite sides of the carrier, and the position sensor is integrated with the holder structure. This merging of components achieves the focus function while minimizing the overall lens assembly volume.
Solution Approach 2:
The patent employs a nested arrangement where the carrier with coils is positioned within the holder, and the sensing magnet is positioned within the space defined by the holder structure. The position sensor is integrated into the holder, creating a nested configuration that maximizes space utilization and reduces the external dimensions of the lens assembly.
2Ease of manufacture
If the position sensor is placed near the welding area, then assembly is simplified, but the sensor accuracy is damaged by high temperature
Solution Approach 1:
The patent introduces a heat-resistant barrier or shielding structure between the welding area and the position sensor. This intermediary element protects the temperature-sensitive position sensor from the high temperatures generated during welding operations, allowing the sensor to maintain its accuracy while still enabling simplified assembly procedures.
Solution Approach 2:
The patent segments the assembly process into distinct temperature zones, with the position sensor located in a low-temperature zone away from the welding area. This spatial segmentation allows welding operations to proceed in high-temperature zones without compromising the position sensor accuracy, while still maintaining overall assembly simplicity.
3Volume of moving object
If the lens driving apparatus is made compact, then the device size is reduced, but the sensitivity and fast focus function are compromised
Solution Approach 1:
The patent optimizes the local quality of magnetic field distribution by strategically positioning the driving magnet and sensing magnet on opposite sides of the carrier at specific locations. This localized optimization of magnetic field strength and uniformity maintains high detection sensitivity and fast focus response even within a compact overall apparatus size.
Solution Approach 2:
The patent employs dynamic coil positioning and current control to maintain high sensitivity in the compact structure. The coils are positioned to maximize magnetic coupling with the driving magnet, and the system dynamically adjusts current distribution to optimize focus speed and detection sensitivity within the constrained compact volume.
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 solution enables a compact, high-sensitivity lens driving apparatus that maintains position sensor accuracy and facilitates fast focusing, while simplifying the assembly process and reducing the impact of high temperatures on the position sensor, thereby achieving a balance between size and functionality.
Implementation Method 1
The position sensor is disposed on the printed circuit board and corresponds to the sensing magnet for detecting a displacement parallel to the optical axis of the sensing magnet
Implementation Method 2
The coil is disposed on an outer surface of the carrier. One of the driving magnets is disposed in the metal cover and corresponds to the coil
Data Source
AI summary
A lens driving apparatus includes a holder, a metal cover, a carrier, a sensing magnet, a printed circuit board, a position sensor, a coil and at least one driving magnet. The metal cover is coupled with the holder and has an opening. The carrier is assembled to a lens assembly having an optical axis, wherein the carrier is disposed in the metal cover and is movable along a direction parallel to the optical axis. The sensing magnet is coupled with the carrier. The printed circuit board is disposed near to one of the four lateral sides of the holder. The position sensor is disposed on the printed circuit board and corresponds to the sensing magnet. The coil is disposed on an outer surface of the carrier. One of the driving magnet is disposed in the metal cover and corresponds to the coil.