Switchable Grating Waveguide for AR Eye Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Augmented Reality (AR) display devices have complex optical systems with large size and weight due to multiple complex lens groups, leading to low light utilization and brightness, as they emit light beyond the human eye's pupil area, resulting in inefficient light distribution and increased power consumption.
Innovation Solution
An optical waveguide element with a first grating comprising switchable sub-grating units that can be controlled between diffraction and non-diffraction states, allowing only the necessary light to exit and adjust the light-exiting region based on the eye's position, using independent control electrodes and electro-optic material layers to manage refractive index and light guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a plurality of complex lens groups are used for projection display, then the optical system can achieve adequate light distribution, but the structure becomes complex and the device weight and volume increase
Solution Approach 1:
The patent divides the optical waveguide layer into multiple independently controllable regions, each corresponding to a specific area of the human pupil. Each region can be independently activated or deactivated to control light extraction, replacing the need for complex lens groups with a segmented, electronically controlled approach to light distribution.
Solution Approach 2:
The patent employs dynamically controllable light-exiting regions that can be adjusted in real-time based on eye tracking data. The boundaries and positions of these regions are not fixed but can move and resize to match the pupil's position and size, enabling adaptive light distribution without mechanical lens adjustments.
2Area of stationary object
If light is emitted beyond the human eye's pupil area, then the optical system covers a wider area, but light utilization efficiency decreases and power consumption increases
Solution Approach 1:
The patent applies local quality by making different regions of the optical waveguide layer have different optical characteristics. Specifically, certain regions are configured to extract light while others remain transparent, with the pattern of light-exiting regions dynamically adjusted to match only the pupil area. This ensures light is emitted precisely where needed (within the pupil) and not wasted in surrounding areas.
Solution Approach 2:
The patent changes the optical parameters (light extraction capability) of different regions of the waveguide layer dynamically. By controlling the refractive index or optical properties of specific regions through electro-optic materials or similar mechanisms, the system can switch between light-exiting and transparent states, adjusting the effective light-exiting area to match the pupil size and position.
3Device complexity
If the light-exiting region is fixed, then the optical system is simpler to design, but it cannot adapt to different eye positions and observation directions
Solution Approach 1:
The patent implements dynamic adaptability by making the light-exiting regions controllable and movable. Based on eye tracking information, the system dynamically adjusts the position, size, and boundaries of light-exiting regions to match the user's pupil location and observation direction. This dynamic adjustment capability enables the system to adapt to different eye positions without requiring multiple fixed optical paths.
Solution Approach 2:
The patent incorporates a feedback mechanism where eye tracking data continuously informs the adjustment of light-exiting regions. The system monitors the user's eye position and pupil size in real-time, and this feedback is used to dynamically reconfigure which regions of the waveguide layer extract light, ensuring optimal performance for the current viewing condition.
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
Improves light utilization and brightness by concentrating light only within the eye's pupil area, reducing unnecessary light emission and power consumption, while maintaining efficient light distribution and image clarity.
Implementation Method 1
the first electrode and the second electrode are configured to generate an electric field after being applied with a voltage, to adjust a refractive index of the first electro-optical material layer
Implementation Method 2
the at least one first sub-grating unit in a diffraction state guides incident light in the optical waveguide layer out of the optical waveguide layer for display
Data Source
AI summary
An optical waveguide element, a control method of the optical waveguide element, a display device and a display method of the display device are provided. The optical waveguide element includes an optical waveguide layer and a first grating, the first grating overlaps with the optical waveguide layer and includes at least one first sub-grating unit, the at least one first sub-grating unit is configured to be switchable between a diffraction state and a non-diffraction state, and the at least one first sub-grating unit in a diffraction state guides incident light in the optical waveguide layer out of the optical waveguide layer for display. The optical waveguide element is capable of adjusting the position of the light-exiting region, the utilization rate of light is high.