Compact Zoom Camera Optics With Dual Moving Lens Groups
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Solution Overview
Problem
Existing camera modules in portable terminals face challenges in achieving high magnification zooming with minimal digital degradation and compact size, while maintaining auto-focusing functionality, due to difficulties in designing optical systems that can move lenses within a small space.
Innovation Solution
A zoom optical system comprising a first, second, and third lens group, where the second and third groups are movable, with a total track length of less than 20 mm, effective focal length greater than 25 mm in telephoto, and f-number less than 4.2, utilizing D-cut lenses and glass lenses with refractive index greater than 1.7 and Abbe number greater than 60, to enable continuous magnification adjustment from wide-angle to telephoto.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a lens is moved to adjust distance between lens and image sensor for auto-focusing, then auto-focusing function is achieved, but it is not easy to design an optical system capable of moving in a small space
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with negative refracting power, second lens group with positive refracting power, third lens group with negative refracting power) that can move independently. This segmentation allows the auto-focusing function to be achieved through coordinated movement of specific lens groups rather than moving the entire lens assembly, thereby reducing the required space.
Solution Approach 2:
The patent utilizes a telephoto configuration where the third lens group is positioned closer to the image sensor than the second lens group. This dimensional arrangement allows the optical system to achieve telephoto functionality with a compact structure by optimizing the spatial distribution of lens groups along the optical axis.
2Adaptability or versatility
If magnification is increased through digital process, then zooming is achieved, but digital degradation occurs
Solution Approach 1:
The patent replaces digital zooming processes with an optical zooming system that uses movable lens groups to physically adjust the focal length and magnification. By using optical mechanisms (moving lens groups with specific refracting powers) instead of digital processing, the system achieves zooming without the associated digital degradation and information loss.
3Adaptability or versatility
If effective focal length is increased for telephoto, then zooming ratio is improved, but f-number increases reducing brightness
Solution Approach 1:
The patent optimizes the refracting powers and positions of the lens groups to achieve a balanced optical system. The second lens group has positive refracting power and the third lens group has negative refracting power, creating a telephoto configuration that achieves high effective focal length while maintaining a reasonable f-number ratio to preserve brightness.
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 system allows for high-resolution zooming with maintained brightness and compact size, achieving continuous magnification adjustment from 5 to 7.5 times with a low chief ray angle and reduced chromatic aberration.
Implementation Method 1
lenses included in the first lens group to fourth lens group include D-cut lenses
Implementation Method 2
The glass lens may have a refractive index greater than 1.7, or an Abbe number greater than 60
Implementation Method 3
a technology of moving a lens to adjust a distance between the lens and an image sensor is being attempted
Data Source
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AI summary
A zoom optical system according to an embodiment of the present invention includes a first lens group, a second lens group, a third lens group, and a fourth lens group which are sequentially disposed in a direction from an object side to an image side, wherein the second lens group and the third lens group are movable, a total track length (TTL) is less than 20 mm, and an effective focal length (EFL) in a telephoto is greater than 25 mm.