Four-Group Zoom Optics for Compact High-Resolution Camera Modules

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Solution Overview

Problem

Existing camera modules in portable terminals face challenges in achieving auto-focusing and zooming functions due to the difficulty in designing a movable optical system within a small space, leading to reduced resolution and digital degradation at higher magnifications.

Innovation Solution

A zoom optical system comprising a first, second, third, and fourth lens groups, where the second and third lens groups are movable, with specific focal length and movement stroke definitions, and lenses with controlled refractive power and abbe numbers to maintain high resolution and enable continuous zooming from wide to telephoto modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a movable lens system is designed to achieve auto-focusing and zooming functions, then magnification adjustment capability is improved, but device complexity and difficulty of design increase due to space constraints in portable terminals

Engineering Contradiction:

Improvemagnification adjustment capabilityVSAvoidoptical system design complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The optical system is divided into four distinct lens groups (first, second, third, and fourth lens groups) with specific functions. The second and third lens groups are designated as movable groups to achieve zooming, while the first and fourth groups remain fixed. This segmentation allows independent optimization of each group's properties and simplifies the overall control mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic optical system where the second and third lens groups can move along the optical axis to adjust magnification from wide-angle to telephoto modes. The movement distances of these groups are specifically controlled according to defined relationships, enabling continuous zooming functionality while maintaining focus.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If digital zooming is used to increase magnification, then magnification capability is improved, but resolution decreases and digital degradation occurs

Engineering Contradiction:

Improvemagnification capabilityVSAvoidimage resolution

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces digital zooming with a mechanical optical zooming system. By physically moving the second and third lens groups, the system achieves true optical magnification without the resolution loss and digital degradation associated with digital zooming. The optical system maintains high resolution across the entire zoom range from 5× to 10×.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If lens movement is implemented to achieve zooming function, then magnification adjustment is improved, but system size and weight increase

Engineering Contradiction:

Improvezooming functionVSAvoidoptical system weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent optimizes the physical parameters of the lens groups, including their diameters, movement distances, and focal lengths. The second and third lens groups are designed with specific diameter constraints and movement stroke relationships that enable zooming while minimizing overall system size and weight. The movement stroke of each group is precisely controlled to achieve the required zoom range without excessive displacement.

Inventive Principle:

Principle #35Parameter changes

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 continuous adjustment of magnification from 5× to 10× while maintaining high resolution, reducing chromatic aberration, and minimizing system size and weight, suitable for integration in portable devices.

Implementation Method 1

a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 which are sequentially arranged in a direction from a subject side to an image side

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

the second lens group and the third lens group are movable, and an effective focal length (EFL) in a wide angle mode is defined by an expression below

Methodology Applied

Scientific EffectFocal length adjustment: Lens

Implementation Method 3

The at least two lenses included in the second lens group may have abbe numbers defined by an expression below: |ABBE3−ABBE4|>10

Methodology Applied

Scientific EffectChromatic aberration correction: Refraction

Data Source

PatentUS12504609B2Optical system and camera module comprising same

Publication Date: 2025.12.23 LG INNOTEK CO LTD

AI summary

A zoom optical system according to an embodiment of the present invention comprises a first lens group, a second lens group, a third lens group, and a fourth lens group which are sequentially arranged in a direction from a subject side to an image side, wherein each of the first lens group to the fourth lens group includes at least two lenses, the second lens group and the third lens group are movable, and an effective focal length (EFL) in a wide angle mode is defined by an expression below.5.5<EFLwideHimage⁢D<6.5.Here, EFLwide is the EFL of the zoom optical system in the wide angle mode, and HimageD is a half value of a diagonal length of a pixel area of an image sensor.