Lens Drive Support Structure for AF Oscillation Control
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Solution Overview
Problem
Conventional camera modules with auto focus (AF) and optical image stabilization (OIS) functions suffer from oscillation due to natural vibrations and spatial restrictions that limit the length of the elastic member.
Innovation Solution
A lens driving device with a modified support member design, featuring non-parallel support units with varying elastic moduli and orientations, including a first support unit with a lower elastic modulus disposed closer to a sensor, minimizes oscillations by optimizing the elastic member's shape and length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the elastic member length is increased to reduce oscillation, then the oscillation resistance improves, but the spatial restriction prevents sufficient length
Solution Approach 1:
The support member is nested within the limited space between the bobbin and housing, utilizing the available spatial volume efficiently. The elastic member is configured to extend along the optical axis direction, nesting its length within the constrained z-direction space rather than requiring lateral space.
Solution Approach 2:
The elastic member is oriented primarily in the optical axis direction (z-axis), transitioning from lateral expansion to axial extension. This dimensional reorientation allows the elastic member to achieve sufficient length for oscillation resistance without violating lateral spatial restrictions of the camera module.
2Measurement precision
If the support member shape is modified to reduce oscillation, then the AF control precision improves, but the device complexity increases
Solution Approach 1:
Different portions of the support member are designed with different properties: the first support unit has a lower elastic modulus to reduce oscillation, while the second support unit has a higher elastic modulus for structural stability. This local differentiation of material or geometric properties optimizes performance without requiring complete redesign of the entire support structure.
Solution Approach 2:
The support member features non-parallel support units with different orientations and elastic moduli, creating an asymmetric structure. The first support unit is oriented differently from the second support unit, allowing differential mechanical response that reduces oscillation while maintaining structural integrity.
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 effectively reduces oscillation phenomena during auto focus feedback control, ensuring stable AF and OIS performance by securing a sufficient length for the elastic member.
Implementation Method 1
a support member elastically connecting the bobbin and the housing
Implementation Method 2
a sensor sensing a position of at least one of the bobbin and the housing
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
1. A lens driving device, comprising: a base (1500); a bobbin (1210) disposed on the base (1500); a first coil (1220) disposed on an outer peripheral surface of the bobbin (1210); a magnet (1320) facing the first coil (1220); and a lower support member (1900) coupled to the bobbin (1210), characterized in that the bobbin (1210) comprises a support portion (1820) supporting the first coil (1220), a separating space (1830) is formed in the support portion (1820), the lower support member (1900) comprises an outer side portion (1911), an inner side portion (1912) coupled to a lower surface of the bobbin (1210), and a connecting portion (1913) connecting the outer side portion (1911) and the inner side portion (1912), a first part of the first coil (1220) is exposed through the separating space (1830) when viewed from a bottom side of the bobbin (1210), and at least a part of the connecting portion (1913) overlaps the first part of the first coil (1220) in an optical axis direction.