Hybrid Optical Lens Diffractive Refractive Aberration Correction

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Solution Overview

Problem

Optical lenses in sensors face challenges in reducing size without compromising optical quality, as size reduction leads to increased optical aberrations such as chromatic and spherical aberrations, and existing hybrid structures do not adequately address these issues.

Innovation Solution

A hybrid optical lens design combining a sub-wavelength grating lens with a refractive lens, where the sub-wavelength grating lens has a focal length inversely dependent on wavelength, reducing the overall wavelength dependence and allowing for improved correction of chromatic and spherical aberrations while minimizing build height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the size of optical lenses is reduced, then the build height of the sensor is reduced, but optical quality deteriorates due to increased chromatic and spherical aberrations and diffraction limits

Engineering Contradiction:
Improvebuild heightVSAvoidoptical quality
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The optical lens is segmented into multiple functional layers: a diffractive lens layer and a refractive lens layer. Each layer addresses specific optical functions, allowing the system to maintain optical quality while reducing overall build height. The diffractive layer handles wavelength-dependent focusing while the refractive layer corrects aberrations, enabling compact design without sacrificing performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a composite lens structure combining diffractive and refractive elements in a single integrated component. This hybrid design leverages the complementary properties of both lens types: diffractive optics for compact focusing and refractive optics for aberration correction, achieving high optical quality in a reduced form factor suitable for mobile devices.

Inventive Principle:
Principle #40Composite materials

2Length of moving object

If a purely diffractive lens design is used to reduce height, then build height is reduced, but chromatic aberration increases significantly

Engineering Contradiction:
Improvebuild heightVSAvoidchromatic aberration
Core Design Contradiction:
Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The refractive lens acts as an intermediary element that mediates the chromatic aberration problem of the diffractive lens. By placing the refractive layer in conjunction with the diffractive layer, the system uses the refractive element's ability to focus all wavelengths at the same point to counterbalance the diffractive element's wavelength-dependent focal lengths, thereby eliminating chromatic aberration while maintaining compact height.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If hybrid structures comprising refractive and diffractive lens elements are used to correct optical aberrations, then optical quality is improved, but build height still leaves room for improvement

Engineering Contradiction:
Improveoptical qualityVSAvoidbuild height
Core Design Contradiction:
Manufacturing precisionVSLength of moving object

Solution Approach 1:

The patent merges the diffractive lens and refractive lens into a single integrated hybrid lens structure where both functionalities coexist in one component. This unified design eliminates the need for separate lens elements, reducing the overall build height while maintaining the optical quality benefits of aberration correction through the complementary action of diffractive and refractive surfaces.

Inventive Principle:
Principle #5Merging (Combining)

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 hybrid lens design significantly reduces chromatic aberrations and allows for a smaller build height, maintaining optical quality by matching the wavelength dependencies of the refractive and sub-wavelength grating lenses, and can be manufactured at the wafer level for mass production.

Implementation Method 1

A sub-wavelength grating lens is disposed on the first surface and comprises a plurality of posts. The plurality of posts is arranged on the first surface and extends from the first surface.

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

A refractive lens is arranged on or below the sub-wavelength grating lens

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

Light incident on the hybrid lens is focused onto a focal plane which is defined by an overall focal length of the hybrid lens. The wave-front of the incoming plane wave is reshaped by the lens according to its focal length.

Methodology Applied
Scientific EffectWave-front reshaping:

Data Source

PatentEP3112924B1Optical hybrid lens and method for producing an optical hybrid lens
Publication Date: 2021.07.28 AUSTRIAMICROSYSTEMS AG
  • EP3112924B1 patent drawingFigure 1A
  • EP3112924B1 patent drawingFigure 1B
  • EP3112924B1 patent drawingFigure 2

AI summary

An optical hybrid lens (100) comprises a substrate (300) having a first surface (301) and a second surface (302) opposite the first surface (301). A sub-wavelength grating lens (200) is disposed on the first surface (301) and comprises a plurality of posts (210, 211, 212, 213, 215, 216). The plurality of posts (210, 211, 212, 213, 215, 216) is arranged on the first surface (301) and the posts extend from the first surface (301). A refractive lens (400) is arranged on the sub-wavelength grating lens (200) at least partly enclosing the plurality of posts (210, 211, 212, 213, 215, 216). Alternatively, the refractive lens (400) is arranged on the second surface (302).