Fifth Lens Inversion for Compact Optical Imaging

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Solution Overview

Problem

Conventional lens systems for digital cameras face challenges in miniaturization due to the need for larger diameters of lenses with positive refractive power to achieve high-resolution imaging, which hinders product size reduction and image quality improvement.

Innovation Solution

A lens system with a fifth lens having negative refractive power and a convex image-side surface, which diverges light rays, allowing for a larger image on the imaging surface with a smaller lens size, facilitating product miniaturization while maintaining or exceeding image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a lens with positive refractive power is used to converge light rays, then image quality is improved, but lens diameter needs to be larger which hinders product miniaturization

Engineering Contradiction:
Improveimage qualityVSAvoidlens diameter
Core Design Contradiction:
Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The patent inverts the conventional approach by using a lens with negative refractive power instead of positive refractive power for the fifth lens. This inversion allows the lens to diverge light rays rather than converge them, enabling the use of a smaller lens diameter while still achieving the desired imaging performance and facilitating product miniaturization.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the refractive power parameter of the fifth lens from positive to negative. This parameter change fundamentally alters the light ray behavior and enables the system to achieve compact dimensions while maintaining image quality, directly resolving the contradiction between lens size and imaging performance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a lens with positive refractive power is used, then light rays are converged, but a larger lens diameter is required which increases product size

Engineering Contradiction:
Improvelight convergence functionVSAvoidproduct size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent applies inversion by switching from positive to negative refractive power for the fifth lens. This changes the light ray behavior from convergence to divergence, allowing the system to achieve compact product size while maintaining reliable imaging function through the modified optical path.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

By changing the refractive power parameter from positive to negative, the patent enables the fifth lens to diverge light rays instead of converging them. This parameter change allows for a smaller lens diameter and reduced product size while preserving the essential imaging function.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If the fifth lens has positive refractive power, then a larger diameter lens is needed to obtain a larger image, but this contradicts product miniaturization goals

Engineering Contradiction:
Improveimage sizeVSAvoidlens diameter
Core Design Contradiction:
Area of stationary objectVSVolume of moving object

Solution Approach 1:

The patent inverts the conventional design by using negative refractive power for the fifth lens. This inversion changes the light ray divergence pattern, allowing the system to produce a sufficiently large image on the imaging surface while using a smaller lens diameter, thus achieving both image size requirements and product miniaturization.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the refractive power parameter of the fifth lens from positive to negative, which fundamentally alters the image formation characteristics. This parameter change enables the system to achieve the desired image size with a compact lens diameter, resolving the contradiction between image size and product miniaturization.

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 proposed lens system effectively reduces the height and width of the lens system by 30%, achieving high image quality resolution and enabling smaller product sizes for applications in mobile devices without compromising image size or quality.

Implementation Method 1

a fifth lens having negative refractive power and having a convex image-side surface, a function of which is to diverge light rays

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3667387B1Lens system, image capture apparatus and device
Publication Date: 2023.04.26 HUAWEI TECH CO LTD
  • EP3667387B1 patent drawingFigure 1
  • EP3667387B1 patent drawingFigure 2
  • EP3667387B1 patent drawingFigure 3

AI summary

This application relates to the field of optical imaging technologies, and discloses a lens system and an image photographing apparatus and device, so as to obtain a larger image on an imaging surface, thereby facilitating product miniaturization. The lens system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens that are sequentially arranged in an optic axis direction from an object side to an image side, where the first lens has a positive refractive power, the second lens has a negative refractive power, the third lens has a negative refractive power, the fourth lens has a positive refractive power, and the fifth lens has a negative refractive power and has a convex image-side surface.