Curved Optical See-Through Lightguide with Dual Abbe Materials

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing wearable electronic eyewear devices face limitations in image quality due to chromatic aberrations and low field of view (FOV) caused by conventional lightguide designs and display technologies, particularly with broad-spectrum displays like OLEDs, which restrict the effectiveness of augmented reality (AR) experiences.

Innovation Solution

The use of two materials with different Abbe numbers in the eyewear device's lightguide system to correct chromatic aberrations, combined with curved lens surfaces and total internal reflection, enhances image quality and FOV by acting as a classical doublet for color correction, specifically addressing issues with OLED and AMOLED displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional lightguide designs are used, then the device can be manufactured with standard components, but chromatic aberrations occur and field of view is limited

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidimage quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies composite materials by combining two different optical materials (first material and second material) with different Abbe numbers in the lightguide system. This composite approach corrects chromatic aberrations caused by broad-spectrum displays while maintaining manufacturability through standardized optical design principles.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the optical parameters of the lightguide system by selecting materials with specific different Abbe numbers and designing curved lens surfaces with particular radii of curvature. These parameter changes enable chromatic aberration correction and expanded field of view while preserving ease of manufacture.

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If broad-spectrum displays like OLED are used, then display quality and contrast ratio are improved, but chromatic aberrations increase

Engineering Contradiction:

Improvedisplay qualityVSAvoidchromatic aberration

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful chromatic aberration effect into a beneficial correction by deliberately introducing optical elements with opposite chromatic properties. The curved lens surfaces and dual-material lightguide design transform the broad-spectrum light's chromatic dispersion into a corrected image, allowing OLED displays to maintain their high display quality without chromatic aberration penalties.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Volume of moving object

If conventional eyewear geometry is used, then device size is reduced, but field of view is limited

Engineering Contradiction:

Improvedevice sizeVSAvoidfield of view

Core Design Contradiction:

Volume of moving objectVSArea of stationary object

Solution Approach 1:

The patent applies curvature principles by designing curved lens surfaces with specific radi of curvature in the lightguide system. These curved surfaces expand the field of view by redirecting light rays from wider angles while maintaining a compact device form factor suitable for eyewear applications.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Length of stationary object

If multiple reflections are implemented in lightguide, then optical path is extended, but chromatic aberrations accumulate

Engineering Contradiction:

Improveoptical pathVSAvoidchromatic aberration

Core Design Contradiction:

Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent uses composite materials with different Abbe numbers positioned at different locations in the optical path to counteract chromatic aberration accumulation. As light undergoes multiple reflections extending the optical path, the dual-material design continuously corrects chromatic dispersion, allowing extended optical paths without proportional increases in chromatic aberration.

Inventive Principle:

Principle #40Composite materials

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 approach significantly improves the perceived image quality and AR experience by reducing chromatic aberrations and increasing the FOV to approximately 40 degrees diagonal, providing a more effective merging of computer-generated and real-world views.

Implementation Method 1

curved lens surfaces and total internal reflection, enhances image quality and FOV

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

Methodology Applied

Scientific EffectChromatic aberration correction: Refraction

Data Source

PatentUS11249312B2Color-corrected curved optical see-through thin lightguide with large field of view in eyewear formfactor

Publication Date: 2022.02.15 GOOGLE LLC

AI summary

An optical device includes a display that emits light toward a lightguide. Display light reflects from lightguide surfaces by total internal reflection (TIR). The display is mounted proximate to the lightguide. The optical device includes a first surface at an eye-side of the optical device and a second surface at a world-side. The optical device includes a first material having a first Abbe number and a second material having a second Abbe number different from the first Abbe number. The first material and the second material cause a color correction to light from the display or alters a chromatic aberration of the light from the display. A head mountable frame supports the display and the lightguide including the first and second materials.