Vision Correcting Displays Using Virtual Image Distance
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Solution Overview
Problem
Presbyopic individuals with limited accommodative range struggle to view electronic device displays clearly without vision aids due to the proximity of the device to their eyes, as they require clear distance vision for both far and near objects.
Innovation Solution
An electronic device with a display configured to provide visual content at a virtual image distance farther from the user than the physical separation, using control circuitry to generate left and right images that fuse at a virtual image distance greater than the physical distance between the eye boxes, employing technologies like computer-generated holograms, waveguide displays, or light-field displays to present images at a desired focal distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the display is held close to the user's eyes, then the device is more convenient to use, but presbyopic users cannot focus on the content clearly
Solution Approach 1:
The patent introduces an optical intermediary system (waveguide, hologram, or light-field display) between the physical display and the user's eye. This intermediary creates a virtual image at a distance that matches the user's accommodative range, allowing close physical proximity while maintaining clear focus. The intermediary decouples the physical distance from the perceived image distance, resolving the contradiction between convenience and focus quality.
2Manufacturing precision
If reading glasses or bifocals are used to view close displays, then content is visible in focus, but display viewing becomes cumbersome
Solution Approach 1:
The display system provides its own focusing solution through integrated optical elements (waveguide, hologram, or light-field display) that create the appropriate virtual image distance. This eliminates the need for external vision aids like reading glasses or bifocals, as the display itself serves the focusing function that would otherwise require separate corrective devices.
3Manufacturing precision
If the virtual image distance is increased to match the user's accommodative range, then presbyopic users can focus clearly, but the physical separation between user and device must be larger
Solution Approach 1:
The patent transitions from a single physical dimension to multiple optical dimensions by creating a virtual image space. The physical display remains close to the user, but the virtual image is projected to a distance that matches the user's accommodative range. This dimensional transformation allows the system to satisfy both the close proximity requirement and the focus quality requirement simultaneously.
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
Enables users with good distance vision to view content in focus without the need for vision aids, even when the device is held close, by placing the image at a virtual distance within their accommodative range, effectively addressing the challenge of presbyopia in electronic device usage.
Implementation Method 1
the left and right images fuse to form a fused image at a virtual image distance that is greater than the physical distance between the eye boxes and the display system
Implementation Method 2
a transmissive spatial light modulator that is illuminated by a plane wave illumination system to provide computer-generated hologram images
Implementation Method 3
a waveguide-based system with an output coupler that ensures that image content is presented at a desired virtual image distance
Implementation Method 4
a light-field display that presents a light field corresponding to an image at the desired virtual image distance
Data Source
AI summary
An electronic device may provide visual content at a virtual image distance that is farther from a user than the physical distance of the device from the user. A display in the device may have a transmissive spatial light modulator and beam steering device that are illuminated by a plane wave illumination system to provide computer-generated hologram images, may have a waveguide-based system that ensures that image content is presented at a desired virtual image distance, or may be a light-field display. The display may be used to display a left image in a left eye box and a right image in a right eye box. When viewed from the eye boxes, the left and right images fuse and are visible at a virtual image distance that is farther from the user than the distance physically separating the eye boxes from the display.