Zoom Optical System with Movable Lens Groups for Compact Camera Modules

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Solution Overview

Problem

Existing camera modules in portable terminals face challenges in implementing an auto-focusing function with zoom capabilities due to digital degradation at higher magnifications and the difficulty of designing a movable optical system in a small space.

Innovation Solution

A zoom optical system comprising a first lens group with fixed lenses, a second movable lens group, and a third movable lens group, allowing continuous adjustment of magnification and focus, with specific focal lengths and movement ratios to maintain a compact size and high resolution, and optionally including optical image stabilization and a right-angle prism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital process is used to increase magnification, then magnification can be increased, but digital degradation occurs

Engineering Contradiction:

ImprovemagnificationVSAvoidimage quality

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces digital magnification processing with a mechanical optical zoom system consisting of multiple movable lens groups. The second and third lens groups physically move to change the optical magnification ratio, providing true optical zoom without digital degradation while maintaining high image quality across different magnification levels.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If lens movement is implemented for auto-focusing, then focus adjustment is achieved, but device complexity increases

Engineering Contradiction:

Improvefocus adjustmentVSAvoidoptical system structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent designs the second and third lens groups to serve dual functions: the second lens group adjusts magnification while the third lens group adjusts focus. This multi-functional design allows the system to achieve both zoom and auto-focus capabilities without requiring separate dedicated mechanisms, thereby reducing overall device complexity while maintaining full functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If movable lens groups are added for zoom and focus, then magnification and focus adjustment are achieved, but space requirement increases

Engineering Contradiction:

Improvezoom and focus capabilityVSAvoidoptical system size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent employs a compact nested arrangement where the second and third lens groups are positioned in sequence within a confined space. The lens groups are designed to move along the optical axis in a nested configuration, allowing each group to have its own movement range while sharing the same spatial envelope. This nesting approach enables both zoom and focus functionality within a minimal overall volume suitable for portable terminals.

Inventive Principle:

Principle #7Nested doll (Nesting)

4Measurement precision

If focal length is increased for high magnification, then magnification is improved, but f-number decreases

Engineering Contradiction:

ImprovemagnificationVSAvoidf-number

Core Design Contradiction:

Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent uses asymmetric power distribution among the lens groups to resolve the magnification-f-number trade-off. The second lens group (zoom group) has asymmetric positive and negative power lenses arranged to provide magnification change, while the third lens group (focus group) has asymmetric design optimized for focus adjustment. This asymmetric configuration allows the system to achieve high magnification (up to 5x) while maintaining a relatively bright aperture (f/3.7 or less) by optimizing the power distribution and spacing of individual lens elements rather than using a symmetric design.

Inventive Principle:

Principle #4Asymmetry

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

Enables continuous zoom adjustment from low to high magnification with maintained high resolution and f-number, ensuring a compact and functional camera module for portable terminals.

Implementation Method 1

the fourth lens may have positive power and a highest power value among the first lens to the seventh lens

Methodology Applied

Scientific EffectLens refraction: Refraction

Implementation Method 2

The third lens may have negative power and a second highest power value among the first lens to the seventh lens

Methodology Applied

Scientific EffectLens refraction: Refraction

Data Source

PatentUS20240369811A1Optical system and camera module comprising optical system

Publication Date: 2024.11.07 LG INNOTEK CO LTD

AI summary

The zoom optical system includes a first lens group, a second lens group, and a third lens group which are serially arranged from the object-side towards the image-side. The first lens group includes a plurality of fixed lenses. The second lens group includes two movable lenses. The third lens group includes two movable lenses. Magnification is adjusted according to the movement of the second lens group. Focus is adjusted according to the movement of the third lens group. The focal length at maximum magnification is at least 13 mm. The f-number at maximum magnification is at most 3.7.