Varifocal Waveguide Display Using Tunable Lenses

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Solution Overview

Problem

Conventional near-eye displays (NEDs) for virtual and augmented reality systems become bulky due to the need for multiple optical components to adjust the focal plane, leading to a heavy and complex design.

Innovation Solution

A waveguide display system utilizing two tunable lenses with adjustable optical powers in different dimensions to control the image plane location, eliminating the need for physically moving components by employing electronically tunable lenses, such as liquid crystal lenses, to dynamically adjust the wavefront of light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional NEDs use multiple optical components (lenses, mirrors) to adjust the focal plane position, then the focal plane can be adjusted for ease of use, but the device becomes bulky and heavy

Engineering Contradiction:

Improveease of useVSAvoidweight

Core Design Contradiction:

Ease of operationVSWeight of stationary object

Solution Approach 1:

The patent replaces mechanical optical components (multiple lenses and mirrors) with a tunable lens that can dynamically adjust its focal length through electrical control. This substitution eliminates the need for bulky mechanical adjustment mechanisms while maintaining the ability to adjust the focal plane for ease of use.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a tunable lens whose optical properties can be dynamically adjusted during operation. The lens can change its focal length in real-time based on user needs, providing the same functionality as multiple fixed optical components but with a single dynamic element that reduces overall device weight and complexity.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If conventional NEDs use multiple optical components to adjust the focal plane, then the focal plane position can be varied, but the device complexity increases

Engineering Contradiction:

Improvevariable focal plane positionVSAvoidcomplexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The tunable lens serves multiple functions that would traditionally require separate optical components. A single tunable lens can adjust focal plane position, control focus, and adapt to different viewing conditions, eliminating the need for multiple specialized components and reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the optical parameters of the lens dynamically by adjusting its focal length through electrical control signals. This allows the same physical component to achieve variable focal plane positions without requiring multiple components with fixed parameters, thereby simplifying the device architecture.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If conventional NEDs use large number and size of optical components, then the focal plane can be adjusted, but the device becomes bulky

Engineering Contradiction:

Improvefocal plane adjustmentVSAvoiddevice size

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

The patent replaces multiple large mechanical optical components with a single tunable lens that can be controlled electrically. This substitution dramatically reduces the physical space required for optical components while maintaining the ability to adjust the focal plane for ease of operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 reduces the bulkiness and complexity of NEDs by allowing for precise control of the image plane without physically moving parts, enhancing user experience and ease of use by expanding light to fill a larger eyebox.

Implementation Method 1

The source waveguide is configured to receive light at the entrance area, expand (e.g., via pupil replication) the light in a first dimension

Methodology Applied

Scientific EffectPupil replication:

Implementation Method 2

The first tunable lens has a first range of optical powers in the first dimension. The first tunable lens adjusts a wavefront of the expanded light to form adjusted light

Methodology Applied

Scientific EffectWavefront adjustment:

Implementation Method 3

The output waveguide is configured to receive the adjusted light emitted from the source waveguide at the input area, expand (e.g., via pupil replication) the adjusted light in a second dimension to form image light

Methodology Applied

Scientific EffectPupil replication:

Implementation Method 4

The second tunable lens has a second range of optical powers in the second dimension. The second tunable lens adjusts a wavefront of the image light

Methodology Applied

Scientific EffectWavefront adjustment:

Data Source

PatentUS10914953B1Varifocal waveguide display using tunable lens

Publication Date: 2021.02.09 META PLATFORMS TECHNOLOGIES LLC

AI summary

A tunable waveguide display includes a source waveguide, a first tunable lens (FTL), an output waveguide, and a second tunable lens (STL). The source waveguide receives light, expands the light in a first dimension, and outputs the expanded light. The FTL adjusts a wavefront of the expanded light to form adjusted light. The output waveguide receives the adjusted light, expands the adjusted light in a second dimension to form image light, and outputs the image light. The STL adjusts a wavefront of the image light. The FTL and the STL control an image plane of the image light.