Auto Focus Control Apparatus Using Perpendicular Coil for Slim Camera Module
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Solution Overview
Problem
Conventional auto focus control apparatuses for camera modules are bulky due to the need for a screw portion and lack precise focus regulation, leading to increased module size and suboptimal preview image quality.
Innovation Solution
The auto focus control apparatus features a coil holder portion integrated perpendicular to the optical axis, eliminating the need for a screw and incorporating a lens guide and resilient means for precise linear movement of the lens barrel, allowing miniaturization and improved focus control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a screw portion is used for focus control, then focus regulation can be achieved, but the module size increases and preview image quality deteriorates
Solution Approach 1:
The patent removes the screw portion from the lens barrel structure, extracting the unnecessary mechanical fastening element. The coil holder portion is directly integrated into the lens barrel without requiring a screw, thereby reducing the overall module size while maintaining focus control functionality through electromagnetic actuation.
Solution Approach 2:
The coil holder portion is integrally formed with the lens barrel, merging two previously separate components (coil holder and lens barrel) into a single integrated structure. This eliminates the need for additional fastening mechanisms like screws, reducing module complexity and size while maintaining structural integrity for precise focus control.
2Device complexity
If manual focus adjustment is used, then module complexity is reduced, but focus precision and preview image quality are insufficient
Solution Approach 1:
The patent replaces manual mechanical focus adjustment with an electromagnetic actuation system. The coil and permanent magnet generate electromagnetic forces that precisely control the lens barrel position, achieving automated focus control with higher precision than manual adjustment while maintaining relatively simple module architecture.
Solution Approach 2:
The focus control mechanism changes the operational parameter from manual mechanical adjustment to electromagnetic force control. By varying the current through the coil, the electromagnetic force changes, enabling precise control of the lens barrel position and thus achieving accurate focus adjustment automatically.
3Ease of operation
If the coil is wound in the optical axis direction, then focus control is achieved, but the thickness of the camera module increases
Solution Approach 1:
The patent changes the winding direction of the coil from the optical axis direction (longitudinal) to a direction perpendicular to the optical axis (radial or circumferential). This dimensional change in coil winding orientation allows the electromagnetic force to still drive focus control while significantly reducing the axial thickness of the module.
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 results in a slim camera module capable of producing high-quality preview images by maintaining initial image resolution and enabling precise focus adjustment, enhancing the camera's ability to capture images without distortion.
Implementation Method 1
The voice coil motor method uses Lorentz forces generated by inductive magnetic forces of coils in magnetic fields formed by permanent magnets for linear movement
Implementation Method 2
Resilient members 6 are provided on the lower side of the lens barrel 3 for providing resilient forces so that the lens barrel 3 can be moved, in a linear fashion, in the direction of the optical axis A1
Data Source
AI summary
A miniaturized auto focus control apparatus for camera module includes: a sensor assembly having an image sensor mounted to a printed circuit board and an infrared filter provided on an upper portion of the image sensor; a lens housing to which a plurality of permanent magnets mounted to an upper portion of the sensor assembly are mounted; a coil mounted into the lens housing; a lens barrel to which a plurality of focus control lenses are mounted in the direction of an optical axis; a lens guide portion integrally provided in the lens housing and engaged on the outer side of the lens barrel to guide the lens barrel so that the lens barrel is moved linearly upward and downward in the direction of the optical axis according to electric fields of the coil and the permanent magnets.