Variable Focus 3D Display Modulating Wavefront Divergence

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Solution Overview

Problem

Conventional stereoscopic displays decouple accommodation and vergence mechanisms, leading to eye fatigue and potential visual system pathologies due to conflicting cues that inhibit natural interpretation of 3D images, where objects at different viewing distances are not accurately represented in focus.

Innovation Solution

A method is developed to produce multi-focal 3D images by providing both 2D image data and depth maps, allowing for wavefront divergence modulation of light to correspond with the fixation viewing distance of objects, enabling accurate accommodation and vergence coupling across a range of focal distances from less than 7 cm to infinity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional stereoscopic displays present conflicting vergence and accommodation cues, then 3D image display is achieved, but eye fatigue and visual system pathologies occur

Engineering Contradiction:

Improve3D image display accuracyVSAvoideye fatigue

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the optical parameters of the display system by introducing variable focus lenses that dynamically adjust the accommodation distance to match the vergence distance. This allows the display to present consistent vergence-accommodation cues by coordinating the focus distance with the stereoscopic depth cues, thereby eliminating eye fatigue while maintaining reliable 3D image display.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system dynamically adjusts the focus distance in real-time based on the displayed stereoscopic content. By using variable focus lenses that can change their optical power, the system maintains dynamic coordination between vergence and accommodation cues, preventing the static mismatch that causes eye fatigue in conventional displays.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If conventional stereoscopic displays use fixed focus distance, then device complexity is reduced, but accurate representation of objects at different viewing distances is compromised

Engineering Contradiction:

Improvefocus mechanismVSAvoidviewing distance accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The variable focus lens system serves multiple functions: it maintains the stereoscopic 3D effect while simultaneously providing accurate accommodation cues for objects at different distances. This multi-functionality allows a single display system to handle both the geometric projection and the optical focus control, achieving viewing distance accuracy without proportionally increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If stereoscopic images are displayed without accommodation cues, then ease of operation is improved, but natural interpretation of 3D images is inhibited

Engineering Contradiction:

Improveviewing comfortVSAvoiddepth perception accuracy

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

The system provides feedback to the visual system by delivering accommodation cues that match the vergence cues. The variable focus lenses adjust the optical focus based on the stereoscopic depth information, creating a feedback loop that reinforces the perceived depth and enables natural interpretation of 3D images while maintaining viewing comfort.

Inventive Principle:

Principle #23Feedback

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 approach allows for comfortable and prolonged viewing of 3D images by maintaining the natural coupling of accommodation and vergence, enabling the brain to accurately interpret viewing distances and reducing eye strain, while ensuring that background objects are fully obscured by foreground objects.

Implementation Method 1

wavefront divergence modulation of light to correspond with the fixation viewing distance of objects

Methodology Applied

Scientific EffectWavefront modulation:

Implementation Method 2

allowing for wavefront divergence modulation of light to correspond with the fixation viewing distance of objects, enabling accurate accommodation and vergence coupling

Methodology Applied

Scientific EffectLight focusing: Focusing

Data Source

PatentUS8248458B2Variable fixation viewing distance scanned light displays

Publication Date: 2012.08.21 UNIVERSITY OF WASHINGTON THROUGH ITS CENTER FOR COMMERCIALIZATION

AI summary

In addition to varying the luminance and chrominance levels of each voxel in an image, a viewing distance for objects within the image is varied to display a multi-focal, three-dimensional image. The focal distance of the voxels is determined by a depth map that indicates a fixation viewing depth of each object. When the image is viewed, there is a natural correspondence between the accommodation and vergence of the viewer's eye. The focal distance of the voxels displayed in the image are modulated using, for example, one or more dynamically variable focus mirrors or lenses, a plurality of fixed focus mirrors or lenses having different focal distances, a plurality of different length optical paths with different focal distance ranges, or at least one spatial light modulator. Light used to produce the image is scanned in two orthogonal directions either before or after the light is focus modulated.