Integrated Lightguide and Corrective Lens for HMD

Solution Overview

Problem

Conventional near-to-eye displays, such as HMDs, are not well-suited for users with ophthalmic corrective lenses due to physical interference and bulkiness, and struggle to simultaneously correct light from the combiner and environmental light, leading to optical aberrations in augmented reality scenes.

Innovation Solution

A corrective prescription lens is integrated with a lightguide to form an optical combiner, using two components with specialized features for light incoupling and outcoupling, allowing for a compact and efficient manufacturing process that accommodates a range of prescription diopters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a separate prescription lens is integrated into the combiner, then prescription correction is achieved, but the device becomes bulky and heavy

Engineering Contradiction:

Improveprescription correction capabilityVSAvoidcombiner weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent combines the lightguide and prescription lens into a single integrated combiner component. The lightguide serves dual purposes: guiding light from the display and providing prescription correction through its optical power, eliminating the need for separate prescription lens inserts and reducing overall device weight and bulk.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lightguide is designed to perform multiple functions simultaneously: it acts as both a light guiding element and a prescription corrective lens. By embedding optical power within the lightguide structure, the combiner becomes a universal component that handles both AR display and vision correction without requiring additional specialized elements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a separate prescription lens is integrated into the combiner, then prescription correction is achieved, but visible boundary lines appear

Engineering Contradiction:

Improveprescription correction capabilityVSAvoidvisual continuity

Core Design Contradiction:

Adaptability or versatilityVSShape

Solution Approach 1:

The patent combines the lightguide and prescription lens into a single integrated combiner component. The lightguide serves dual purposes: guiding light from the display and providing prescription correction through its optical power, eliminating the need for separate prescription lens inserts and reducing overall device weight and bulk.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If the combiner is worn close to the eye, then AR viewing is enabled, but vertex distance for corrective lenses is limited

Engineering Contradiction:

ImproveAR viewing capabilityVSAvoidvertex distance

Core Design Contradiction:

Ease of operationVSLength of stationary object

Solution Approach 1:

The patent combines the lightguide and prescription lens into a single integrated combiner component. The lightguide serves dual purposes: guiding light from the display and providing prescription correction through its optical power, eliminating the need for separate prescription lens inserts and reducing overall device weight and bulk.

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

This integration reduces bulk and weight, provides seamless prescription correction, and eliminates visible boundary lines, enhancing the user experience by ensuring clear and focused augmented reality viewing without optical aberrations.

Implementation Method 1

a lightguide, configured to act upon light traveling within the lightguide to change at least one of the direction that the light is traveling

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

an outcoupler, configured to reflect the display light at an angle less than the critical angle so that the display light is directed out of the combiner

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS12147039B2Freeform lens with integrated lightguide and method of manufacture

Publication Date: 2024.11.19 GOOGLE LLC

AI summary

A head mounted display (HMD) device and method of manufacturing the same. The HMD includes a frame housing a micro-display to project display light, a lightguide configured to receive the display light from the micro-display, and a corrective layer having a world-side surface coupled to the eye-side surface of the lightguide. The lightguide is further configured to have a world-side surface with a radius of curvature based on an ophthalmic corrective prescription and an eye-side surface having an outcoupler feature formed thereon such that the coupled lightguide and corrective layer form a lens configured to fit within the frame.