Lens Drive Device Stopper Corner Chamfering
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Solution Overview
Problem
Conventional lens drive devices for camera modules in mobile phones are prone to breakage and distortion due to drop impacts, and they generate scrap easily due to the design of stopper convex portions which collide with the frame, leading to chipping and increased size.
Innovation Solution
A lens drive device with at least three stopper convex portions on the lens holder and corresponding stopper concave portions on the frame, where the convex intersection corners are chamfered or have an R curved surface to prevent collision, and the use of a magnet component to limit lens holder movement without increasing parts, along with elastic members and vibration absorption members to prevent resonance and improve focus accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stopper convex portions are designed with sharp corners to limit lens holder movement, then the stopping function is effective, but the corners collide with the frame during drop impacts causing chipping, breakage, and scrap generation
Solution Approach 1:
The patent applies curvature by forming an R-shaped curved surface at the corner portion of the stopper convex portion instead of using sharp corners. This curved surface prevents direct contact between the stopper corner and the frame's concave portion during drop impacts, eliminating chipping and breakage while maintaining the stopping function. The curved geometry allows impact forces to be distributed along the curved surface rather than concentrated at a sharp corner.
2Reliability
If eight stopper convex portions are provided in the circumferential direction to limit both upward and downward movement, then the stopping coverage is complete, but the device size increases and complexity rises
Solution Approach 1:
The patent extracts only the essential stopping function by providing stopper convex portions at only three locations (0°, 120°, and 240° positions) in the circumferential direction rather than eight positions. The chamfered corner design enhances the stopping effectiveness at these reduced positions, allowing the device to maintain reliable movement limitation with fewer components, thereby reducing device complexity and size.
3Manufacturing precision
If stopper convex portions with sharp corners are used to precisely limit lens holder axial movement, then the positioning precision is high, but the corners are prone to chipping and scrap generation during handling and drops
Solution Approach 1:
The patent applies curvature by forming an R-shaped curved surface at the corner portion of the stopper convex portion. This curved geometry maintains precise positioning function while preventing stress concentration at sharp corners during handling and drop impacts, thereby eliminating chipping and scrap generation without sacrificing positioning precision.
Solution Approach 2:
The patent applies preliminary action by forming chamfered surfaces at the corner portions of the stopper convex portions before assembly. These chamfered surfaces pre-position the stopper corners away from direct contact with the frame's concave portions, preventing impact damage during handling and drops while maintaining accurate lens holder positioning.
4Strength
If the frame and lens holder are designed with rigid structures to maintain structural integrity, then the mechanical strength is high, but drop impacts cause breakage and distortion due to impact force concentration
Solution Approach 1:
The patent applies curvature by forming an R-shaped curved surface at the corner portion of the stopper convex portion. This curved geometry prevents direct impact between rigid components during drops, distributing impact forces along the curved surface rather than concentrating them, thereby preventing breakage and distortion while maintaining structural integrity.
Solution Approach 2:
The patent applies beforehand cushioning by designing the stopper convex portion with chamfered corner surfaces that prevent direct contact with the frame's concave portions. This design cushioning effect protects the rigid frame and lens holder structures from impact forces during drops, preventing breakage and distortion.
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 design enhances durability by preventing breakage and distortion, reduces scrap generation, achieves downsizing, and improves focus accuracy by limiting lens holder movement and absorbing vibrations, thus preventing resonance and blur during image capture.
Implementation Method 1
a convex intersection corner between the first convex end surface and the convex side surface is provided with one of a chamfering portion and an R curved surface portion so as not to touch a concave intersection corner between the concave bottom surface and the concave side surface
Implementation Method 2
The frame may be provided with a magnet component constituting a part of the drive portion in the light axis direction
Implementation Method 3
along with elastic members and vibration absorption members to prevent resonance and improve focus accuracy
Implementation Method 4
along with elastic members and vibration absorption members to prevent resonance and improve focus accuracy
Data Source
AI summary
A lens drive device includes a lens holder capable of holding at least one lens and a frame arranged around the holder and holding the holder relatively movable along a light axis of the lens. At least three stopper convex portions protruding toward the frame are formed on an outer circumference of the holder. Stopper concave portions housing each of the stopper convex portions are formed on the frame correspondingly to the stopper convex portions. A convex intersection corner between the first convex end surface and the convex side surface has a chamfering portion or an R curved surface portion to avoid touching a concave intersection corner between the concave bottom surface and the concave side surface.