Near-Eye Display Optics for Wide Eye-Box Vision Correction
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Solution Overview
Problem
Conventional near-eye display systems fail to provide clear images for users with visual impairments without requiring customized lenses, and they suffer from limitations in field of view, depth of field, and eye-box size, leading to discomfort and reduced usability.
Innovation Solution
A near-eye display system incorporating a pixelated optical shutter and a transmissive retro-reflector, which selectively passes and retro-reflects light to converge on the user's eye, allowing for clear images with a wide field of view and deep depth of field, and expanding the eye-box through adjustable apertures and an eye tracker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a micro-aperture is used in the pixelated optical shutter, then the depth of field is increased and image quality is improved, but the eye-box size becomes limited
Solution Approach 1:
The patent introduces a transmissive retro-reflector that creates a virtual aperture positioned at a different spatial location (in front of the user's eye) rather than relying solely on the physical micro-aperture in the optical shutter. This dimensional transformation allows the system to maintain the optical benefits of a small aperture while expanding the physical eye-box area, as users can move their eyes within a larger region and still receive properly directed light through the retro-reflector geometry.
2Manufacturing precision
If customized optical lenses are added for users with visual impairments, then clear images can be provided, but the device complexity and manufacturing cost increase
Solution Approach 1:
The transmissive retro-reflector serves multiple functions simultaneously: it expands the eye-box, corrects for various vision impairments (myopia, hyperopia, astigmatism), and maintains clear image quality for all users without requiring customized lenses. This universal component replaces the need for individualized optical corrections, simplifying the overall device architecture while achieving the same visual correction goals.
Solution Approach 2:
The system achieves vision correction by changing the optical path geometry through the retro-reflector rather than changing lens parameters. The retro-reflector's fixed geometric configuration naturally directs light to converge appropriately for different eye positions and vision types, eliminating the need to adjust lens focal lengths or add customized optical elements for each user.
3Area of stationary object
If the aperture size is increased to expand the field of view, then the field of view improves, but the depth of field decreases and image quality deteriorates
Solution Approach 1:
The transmissive retro-reflector acts as an intermediary optical element that decouples the relationship between aperture size and depth of field. It receives light from the display panel through the micro-aperture and redirects it to the user's eye, allowing the physical aperture to remain small (maintaining deep depth of field) while the retro-reflector's geometry provides the field of view expansion that would otherwise require a larger aperture.
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 clear images for users with varying vision without customized lenses, providing a wide field of view, deep depth of field, and a comfortable wearing experience by alleviating trade-offs between image quality and depth of field.
Implementation Method 1
a pixelated optical shutter disposed to be spaced apart from a front surface of the display panel by a predetermined distance, and configured to selectively pass light from the display panel through an aperture formed therein
Implementation Method 2
a transmissive retro-reflector configured to transversely retro-reflect a portion of the light diverging after passing through the aperture of the pixelated optical shutter so that the portion of the light converges on a viewpoint of a position of a user's eye
Implementation Method 3
a collimation lens disposed between the display panel and the pixelated optical shutter and configured to collimate light emitted from each pixel of the display panel
Data Source
AI summary
A near-eye display system may comprise: a display panel; a pixelated optical shutter disposed to be spaced apart from a front surface of the display panel by a predetermined distance, and configured to selectively pass light from the display panel through an aperture formed therein; and a transmissive retro-reflector configured to transversely retro-reflect a portion of the light diverging after passing through the aperture of the pixelated optical shutter so that the portion of the light converges on a viewpoint of a position of a user's eye, wherein the aperture of the pixelated optical shutter and the viewpoint in which the transversely retro-reflected light converges on the position of the user's eye form a symmetry with respect to the transmissive retro-reflector.