Holographic Waveguide Light Field Display for Compact AR
Solution Overview
Problem
Current light field displays for virtual and augmented reality are bulky and lack transparency, making them unsuitable for applications like augmented reality, where a compact and transparent solution is required.
Innovation Solution
A compact transparent light field display based on a holographic waveguide, incorporating a laser emitter, optical modulator, electronically controllable beam focus modulator, array of beam scanning elements, waveguide with input and output gratings, and an eye tracker to focus light onto an eye accommodation surface and scan it according to the viewer's gaze direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional light field displays use arrays of lenses to project phase distribution, then the display can achieve light field effects, but the device becomes bulky and lacks transparency
Solution Approach 1:
The patent replaces traditional mechanical lens arrays with a waveguide-based optical system. The waveguide uses diffraction gratings and total internal reflection to guide and project light, eliminating the need for bulky mechanical lens components while maintaining light field display functionality. This substitution of mechanical optical elements with waveguide physics enables compact, transparent display integration.
Solution Approach 2:
The patent employs thin waveguide substrates that can be integrated into transparent surfaces such as eyeglass lenses or display panels. These thin film waveguides maintain optical performance while providing a compact, transparent form factor that traditional lens arrays cannot achieve. The waveguide structure allows light to be projected through transparent materials without significant volume increase.
2Volume of moving object
If waveguide displays are used to provide compact transparent display, then the display becomes compact and transparent, but achieving high resolution light field effects becomes more difficult
Solution Approach 1:
The patent divides the waveguide into multiple discrete output gratings or out-coupling points, each responsible for projecting light to specific angular directions or spatial locations. This segmentation allows precise control over light field resolution by independently optimizing each grating's parameters while maintaining overall system compactness. The segmented approach enables high-resolution light field effects through coordinated operation of multiple discrete optical elements.
Solution Approach 2:
The patent utilizes the waveguide's internal dimensional space to achieve resolution enhancement. By projecting light through multiple depth planes within the waveguide and using angular multiplexing, the system achieves high light field resolution without increasing external device volume. The third dimension (depth within waveguide) is exploited to create multiple image surfaces distributed within the viewing volume.
3Reliability
If eye tracking is implemented to focus light onto accommodation surface, then the display achieves high optical performance, but the device complexity increases
Solution Approach 1:
The patent integrates eye tracking functionality into the existing waveguide display structure, allowing the same optical components to serve dual purposes: both displaying images and tracking eye position. The waveguide's light guiding capability is used for both image projection and eye gaze detection, reducing the need for separate dedicated eye tracking hardware and thereby limiting complexity increase while maintaining high optical performance.
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 solution provides a compact, transparent, and high-performance light field display capable of projecting a 3D scene with high resolution, suitable for virtual and augmented reality applications by accurately focusing and scanning light based on the viewer's gaze direction, enhancing optical performance and user experience.
Implementation Method 1
an input grating for coupling image light into a TIR path
Implementation Method 2
coupling image light into a TIR path
Implementation Method 3
an output grating for extracting light from the waveguide for viewing
Data Source
AI summary
A light field display, having at least one laser emitter, an optical modulator for modulating light from the laser emitter with video information; a beam focus modulator; an array of beam scanning elements; an electrically controllable beam focus modulator; and at least one at least one waveguide having at least one transparent substrate, an input grating and an output grating for extracting light from the waveguide; and an eye tracker is provided.