Variable Virtual Focus Adjuster for Augmented Reality Displays
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Solution Overview
Problem
Conventional augmented reality displays lack the ability to dynamically adjust the focus of virtual objects to match the user's changing location and perspective, resulting in virtual objects appearing out of focus or blurry when viewed through see-through near-eye displays.
Innovation Solution
The technology employs a see-through display device with a microdisplay assembly that includes a variable virtual focus adjuster, allowing for the adjustment of focal regions by changing the displacement between optical elements or adjusting the focal length of lenses, ensuring virtual objects appear in focus as the user moves, using techniques such as artificial depth of field and rapid image sweeping to simulate natural focus changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed focal distance is used for virtual objects in augmented reality displays, then the optical system is simple and stable, but the virtual objects do not move in and out of focus naturally as the user moves, reducing realism
Solution Approach 1:
The patent implements a variable focus optical system where the focal distance can be dynamically adjusted based on the user's position and the virtual object's location. The optical engine transitions from a fixed-focus design to a dynamic focus system that adapts to changing viewing conditions, allowing virtual objects to naturally come in and out of focus as the user moves through the environment.
Solution Approach 2:
The system changes the focal parameter of the optical system based on calculated distances between the user and virtual objects. By adjusting the focal distance parameter dynamically, the system creates realistic depth perception without requiring complex mechanical adjustments to the entire optical assembly.
2Adaptability or versatility
If the focal region is adjusted to keep virtual objects in focus as the user moves, then realism is improved, but the computational requirements and processing time increase
Solution Approach 1:
The system pre-calculates focal distances and prepares focus adjustments in advance based on the user's current position and intended movement. By anticipating focus requirements before the user actually needs them, the system reduces perceptible processing delays and maintains smooth focus transitions.
Solution Approach 2:
The optical system continuously monitors the user's position and the relative distances to virtual objects, using this feedback to dynamically adjust the focal region. This closed-loop control ensures that focus adjustments are made in real-time based on actual viewing conditions, maintaining realism while optimizing processing efficiency.
3Reliability
If multiple focal regions are displayed rapidly to simulate natural focus changes, then temporal image fusion creates the perception of depth, but the display complexity and power consumption increase
Solution Approach 1:
The system displays multiple focal regions in rapid succession at a frequency that exploits human temporal image fusion. By cycling through different focal planes periodically at the optimal rate, the system creates the perception of continuous depth variation without requiring all focal regions to be displayed simultaneously, thus reducing power consumption.
Solution Approach 2:
Rather than maintaining multiple static focal regions simultaneously, the system dynamically switches between focal regions based on the user's current focus point. This dynamic approach reduces the need for continuous high-power operation of multiple display elements, optimizing energy efficiency while maintaining depth perception accuracy.
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 solution enables virtual objects to appear naturally in and out of focus as the user views them, enhancing the realism and immersion of augmented reality experiences by maintaining focus alignment with the user's perspective, even when the user's location changes relative to the virtual objects.
Implementation Method 1
the adjuster changes the displacement along the optical path between at least two elements of the microdisplay assembly to change the focal region of a virtual object in an image
Implementation Method 2
a focal length of an optical element may be adjusted to obtain the desired focal region
Implementation Method 3
polarization of at least one birefringent lens may be changed
Implementation Method 4
a radius of curvature of a fluid or liquid lens may be adjusted
Data Source
AI summary
The technology provides an augmented reality display system for displaying a virtual object to be in focus when viewed by a user. In one embodiment, the focal region of the user is tracked, and a virtual object within the user focal region is displayed to appear in the focal region. As the user changes focus between virtual objects, they appear to naturally move in and out of focus as real objects in a physical environment would. The change of focus for the virtual object images is caused by changing a focal region of light processing elements in an optical path of a microdisplay assembly of the augmented reality display system. In some embodiments, a range of focal regions are swept through at a sweep rate by adjusting the elements in the optical path of the microdisplay assembly.