Five-Group Imaging Lens Camera Shake Correction

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Solution Overview

Problem

Existing imaging lenses for electronic cameras face challenges in achieving high camera shake correction performance while maintaining compactness and effectively correcting aberrations, especially at low shutter speeds and for short-distance imaging.

Innovation Solution

The design incorporates a five-group lens configuration with specific refractive power distributions and movement trajectories for the lens groups, including a third lens group moved intersecting the optical axis for camera shake correction, and conditional expressions to optimize focal lengths and Abbe numbers, ensuring effective aberration correction and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the amount of movement of the lens group for camera shake correction is increased, then camera shake correction performance is improved, but the size of the lens system in radial direction increases

Engineering Contradiction:

Improvecamera shake correction performanceVSAvoidlens system size in radial direction

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies parameter changes by optimizing the refractive powers and positions of lens groups. Specifically, it sets the refractive power of the third lens group (camera shake correction group) to have a specific relationship with the overall focal length, and positions the aperture stop at a calculated distance from the third lens group. This allows achieving effective camera shake correction with controlled lens system dimensions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the third lens group movable in a direction intersecting the optical axis for camera shake correction, while the first lens group remains stationary and the second and fourth lens groups move along the optical axis for focusing. This dynamic configuration allows the system to correct camera shake without increasing radial size.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the imaging lens is designed for short-distance imaging with high magnification, then imaging capability at close distances is improved, but aberration correction becomes more difficult

Engineering Contradiction:

Improveshort-distance imaging capabilityVSAvoidaberration correction

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the lens system into five distinct lens groups with specific functions: first group (positive, stationary), second group (negative, focuses), third group (positive, camera shake correction), fourth group (positive, focuses), and fifth group (negative). This segmentation allows each group to be optimized for its specific function while working together to correct aberrations across the imaging range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by assigning specific optical characteristics to different lens groups. The third lens group has specific refractive power and position optimized for camera shake correction, while other groups have characteristics optimized for their focusing and aberration correction functions. This localized optimization enables effective aberration correction throughout the imaging range including short distances.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If a rear lens group configuration is used for camera shake correction, then the lens can be attached to mirror-less cameras, but space for attaching the lens becomes difficult to secure

Engineering Contradiction:

Improvecompatibility with mirror-less camerasVSAvoidspace for attaching lens

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent implements dynamics by positioning the camera shake correction mechanism (third lens group) within the lens system rather than at the rear, allowing it to be integrated into the lens structure itself. This enables the lens to function with mirror-less cameras while maintaining compact dimensions suitable for attachment spaces.

Inventive Principle:

Principle #15Dynamics

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

This configuration enables efficient camera shake correction and minimizes aberration variations from infinity to close distances, achieving high image quality and compactness, suitable for short-distance imaging and mirror-less cameras.

Implementation Method 1

a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10295801B2Imaging lens and imaging apparatus

Publication Date: 2019.05.21 FUJIFILM CORP

AI summary

The imaging lens includes, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power. In a case of changing focus from an object at infinity to an object at the closest distance, the first lens group is immovable, and the second lens group and the fourth lens group are moved in an optical axis direction along different trajectories from each other. The third lens group is moved in a direction intersecting the optical axis to perform camera shake correction.