Dynamic Waveguide Eye Box Control for Efficient Light Delivery
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Solution Overview
Problem
Existing near-eye display devices waste power by continuously delivering image light to large, static eye boxes that are not being viewed due to eye movement, leading to inefficient light usage and reduced image quality.
Innovation Solution
Implementing a dynamically controllable output coupler with zones that activate or deactivate based on eye tracking, allowing a smaller, movable eye box with higher light efficiency and improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large, static eye box is used to maintain full field-of-view, then the user can view the display from various positions, but power is wasted by continuously delivering light to portions of the eye box not being viewed
Solution Approach 1:
The patent applies dynamics by transitioning from a static eye box to a dynamic, movable eye box that can be repositioned based on detected eye position. The output coupler is configured to move the eye box within the waveguide, allowing the system to adapt light delivery to the user's actual viewing position in real-time, thereby eliminating waste while maintaining full field-of-view coverage.
Solution Approach 2:
The system uses feedback from the eye position detection system to control the position of the eye box. The detected eye position information feeds back to the controller, which adjusts the output coupler to reposition the eye box accordingly, creating a closed-loop system that optimizes light delivery based on actual user viewing behavior.
2Illumination intensity
If a large, static eye box is used to ensure full field-of-view, then all areas are always illuminated, but light efficiency is reduced due to continuous illumination of unviewed areas
Solution Approach 1:
The patent extracts only the necessary portion of light delivery by repositioning the eye box to match the user's actual viewing position. Instead of illuminating the entire static eye box area, the system extracts and delivers light only to the relevant portion that the user is currently viewing, thereby improving light efficiency while maintaining adequate illumination intensity in the active region.
3Device complexity
If the eye box position is fixed, then the optical system is simpler, but the system cannot adapt to eye movement and wastes power on unviewed areas
Solution Approach 1:
The patent introduces an intermediary component (the movable output coupler) that acts as a mediator between the fixed optical system and the moving eye. This intermediary element enables dynamic adaptation to eye movement while maintaining relative simplicity in the overall optical architecture, as the output coupler serves as the primary mechanism for eye box repositioning without requiring complete system redesign.
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
Reduces power consumption by directing light only to the viewed portion of the eye box, maintaining full field-of-view while conserving power and enhancing image quality.
Implementation Method 1
one or more optical waveguides may be used to direct light from an image source along an optical path toward a user's eye(s)
Implementation Method 2
the output coupler including a plurality of zones, each zone activatable via a dynamically controllable output coupling element of the zone
Data Source
AI summary
One disclosed example provides a near-eye display device. The near-eye display device comprises an eye tracking system configured to determine a position of an eye of a user relative to the near-eye display device, and a waveguide including at least an input coupler and an output coupler, the output coupler including a plurality of zones, each zone activatable via a dynamically controllable output coupling element of the zone. The near-eye display device further comprises an image source configured to output image light to the input coupler, and a controller configured to selectively activate one or more zones of the output coupler based at least on the position of the eye.