MEMS Auto-Focus Lens Module with Inverted Movable First Element
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Solution Overview
Problem
Conventional camera devices using MEMS actuators for auto-focusing face limitations as they cannot utilize the optical system designed for VCM actuators, necessitating a new power structure for high-resolution lens modules.
Innovation Solution
A lens module configuration comprising a sequence of lenses with specific refractive powers and aspherical surfaces, including a first positive lens, a second negative lens, a third positive lens with an inflection point, and a fourth negative lens, optimized for MEMS actuator-driven auto-focusing, with an iris positioned towards the object side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a VCM actuator is used for auto-focusing, then the lens barrel can reciprocate to perform auto-focusing, but the system cannot be adapted to MEMS actuators which can only shift one lens
Solution Approach 1:
Instead of making the entire lens barrel movable as in VCM systems, this patent inverts the approach by making only the first lens movable while keeping the lens barrel fixed. This inversion allows compatibility with MEMS actuators that can only displace a single lens, while still achieving auto-focusing functionality through the selective movement of the first lens element.
2Device complexity
If only one lens is shifted by MEMS actuator, then the actuator structure is simplified, but the optical system designed for VCM cannot be used
Solution Approach 1:
The patent applies local quality by giving the first lens different properties from the other lenses - specifically, the first lens is designed with movable mounting structure and specific optical characteristics (positive refractive power, aspherical surfaces) that enable it to be shifted by the MEMS actuator for auto-focusing, while the remaining lenses stay fixed in the lens barrel.
3Manufacturing precision
If aspherical surfaces are used on both object and image sides of each lens, then aberration compensation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs parameter changes by specifying precise aspherical surface parameters for each lens surface. The aspherical shapes are defined by mathematical expressions with specific coefficients that optimize aberration compensation. This allows achieving high manufacturing precision through controlled parameter specification rather than complex manufacturing processes.
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
Enhances image performance by providing effective aberration compensation and zoom functionality, ensuring improved image quality across various zoom positions.
Implementation Method 1
a first lens having a positive (+) refractive power and capable of moving for zooming operation
Implementation Method 2
a second lens having a negative (−) refractive power
Implementation Method 3
a third lens having a positive (+) refractive power and having an inflection point at an image surface
Implementation Method 4
a fourth lens having a negative (−) refractive power
Implementation Method 5
each of the first through fourth lens is aspherical on an object side surface and an image side surface
Data Source
AI summary
The present disclosure relates to a lens module, the module including a first lens having a positive (+) refractive power and capable of moving for zooming operation; a second lens having a negative (−) refractive power; a third lens having a positive (+) refractive power and having an inflection point at an image surface; and a fourth lens having a negative (−) refractive power.