Auto-focus Actuator Dust Barrier Design
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Solution Overview
Problem
Existing camera module designs with auto-focus actuator units fail to effectively prevent dust from reaching the infrared cut filter during lens focusing, as the dust barrier solutions in prior art either act downstream or are structurally compromised, allowing dust to bypass or adhere to the filter.
Innovation Solution
An auto-focus actuator unit with a dust barrier integrated on the top surface of the bottom plate, maintaining vertical overlap with the lens carrier throughout its travel, ensuring no path is opened for dust to exit the actuator unit, and optionally featuring a bottom recess to secure the lens carrier and enhance sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a dam member is provided to protect the IR cut filter from dust, then the filter is partially protected, but the dust can still climb over the obstacle and reach the filter
Solution Approach 1:
The invention transitions from a 2D dam member structure to a 3D dust barrier structure that extends vertically from the bottom plate. The dust barrier has a height dimension that maintains overlap with the lens carrier throughout its travel range, creating a three-dimensional containment structure that completely blocks dust migration paths rather than merely obstructing them at the filter level.
Solution Approach 2:
The dust barrier is positioned upstream in the dust migration path, preventing dust from exiting the actuator unit before it can reach the lens carrier or filter. By blocking the dust path at the bottom plate level rather than at the filter level, the invention takes preliminary protective action that eliminates the need for downstream obstruction.
2Adaptability or versatility
If the lens carrier is lifted up for macro focusing, then focusing capability is improved, but a path opens up allowing dust to reach the filter
Solution Approach 1:
The dust barrier height is specifically designed to maintain vertical overlap with the lens carrier throughout its entire dynamic travel range from infinity to macro focusing positions. As the lens carrier moves dynamically during focusing operations, the dust barrier continuously adapts by maintaining overlap, ensuring the dust path remains blocked at all focusing positions.
Solution Approach 2:
The dust barrier acts as an intermediary structure between the lens carrier and the external environment. It creates a protective interface that allows the lens carrier to move freely for focusing while preventing dust from following the carrier's motion path to reach the filter.
3Object-affected harmful factors
If the dam member projects upwards from the base, then dust obstruction is provided, but coupling with the actuator unit becomes difficult
Solution Approach 1:
Instead of projecting the dust barrier upward from the base (external approach), the invention integrates the dust barrier directly onto the top surface of the bottom plate (internal approach). This inversion of the design approach allows the dust barrier to be incorporated within the actuator unit structure, facilitating easier coupling with the housing frame and lens carrier while maintaining effective dust blocking.
Data Source
AI summary
An auto-focus actuator unit including a lens carrier slidably received within a stationary housing frame for a reciprocating motion provided by an actuator is described. The housing frame being carried by a bottom plate provided with an opening, in correspondence with one or more lenses carried by the lens carrier, and with a dust barrier projecting towards the lens carrier and having such a height as to maintain a vertical overlap with the lens carrier over the whole travel of the latter.