Camera Module Sensing Yoke for Compact Autofocus Position Measurement
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Solution Overview
Problem
The miniaturization of camera modules in mobile communication terminals and smartphones poses challenges in reducing the size of actuators for autofocusing and optical image stabilization while maintaining precise position measurement, as hall sensors used for this purpose are difficult to miniaturize and increase manufacturing costs.
Innovation Solution
A camera module design incorporating a sensing yoke and sensing coil configuration, where the sensing yoke is made of stainless steel and has a body unit and extension units extending in the optical axis direction, allowing for precise position measurement of the lens module while maintaining a compact form factor, thereby improving sensing sensitivity and control performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hall sensors are used for position measurement, then measurement precision is improved, but device size increases and manufacturing cost increases
Solution Approach 1:
The patent replaces the mechanical hall sensor system with an electromagnetic sensing system consisting of a sensing coil and magnetic member. This substitution eliminates the need for complex mechanical structures while achieving precise position measurement through electromagnetic induction, thereby reducing overall device size while maintaining measurement accuracy.
Solution Approach 2:
The patent changes the measurement approach from direct magnetic field sensing (hall sensor) to electromagnetic induction sensing (sensing coil detecting changes in magnetic flux). This parameter change in the sensing mechanism allows for more compact design while preserving measurement precision, as the coil-based system requires less space than traditional hall sensor assemblies.
2Measurement precision
If hall sensors are used for position measurement, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive hall sensors with a more cost-effective electromagnetic sensing system using simple coils and magnetic members. These components are generally less expensive to manufacture and assemble, reducing overall manufacturing costs while maintaining the required measurement precision for lens module positioning.
Solution Approach 2:
The patent employs inexpensive magnetic members and sensing coils that can be easily manufactured and replaced if necessary. These components are simpler and cheaper than hall sensors, allowing for cost-effective production while achieving the same functional outcome of precise position measurement.
3Volume of moving object
If actuator size is reduced for miniaturization, then device size is reduced, but position measurement precision deteriorates
Solution Approach 1:
The patent replaces mechanical position measurement mechanisms with an electromagnetic sensing system that can achieve high precision in a compact form. The sensing coil and magnetic member configuration provides accurate position feedback without requiring large mechanical structures, enabling miniaturization while preserving measurement precision.
Solution Approach 2:
The patent transitions from mechanical dimension-based measurement to electromagnetic field-based measurement. By utilizing the electromagnetic dimension rather than mechanical displacement, the system achieves precise measurement capabilities in a reduced physical footprint, allowing actuators to be smaller without sacrificing measurement accuracy.
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 design enables precise measurement of the lens module position, enhancing the control performance of the camera module while minimizing its size, thus addressing the challenges of miniaturization and cost associated with traditional hall sensors.
Implementation Method 1
a position measuring unit including a sensing yoke disposed on the carrier and a sensing coil facing the sensing yoke
Implementation Method 2
a focus adjusting unit including a magnet disposed on the carrier and a coil disposed to face the magnet
Data Source
AI summary
A camera module includes a carrier accommodating a lens module, a housing accommodating the lens module and the carrier, a focus adjusting unit configured to move the lens module and the carrier in an optical axis direction, and a position measuring unit including a sensing yoke mounted on the carrier and a sensing coil facing the first sensing yoke. The sensing yoke includes a body unit and an extension unit extending in the optical axis direction from the body unit.