Retroreflective Light Field Display for AR Vergence Matching
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Solution Overview
Problem
Conventional light field displays for augmented reality (AR) and virtual reality (VR) face issues with brightness and complexity, making them more expensive and less desirable.
Innovation Solution
A projected head-mounted display (PHMD) with image projectors that modulate focal plane distance in synchronization with image scenes, utilizing a retroreflective screen or surface to present multiple planes of focus, approximating a light field display by leveraging phase conjugate reflection properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional light field display techniques are used, then multiple planes of focus can be presented, but the device complexity and cost increase significantly
Solution Approach 1:
The patent uses a retroreflective screen to create virtual images that copy the appearance of multiple focal planes without requiring multiple physical display elements. The retroreflector returns projected light to the user's eyes, creating the illusion of multiple focal planes through optical reflection rather than multiple physical planes.
Solution Approach 2:
The retroreflective screen acts as an intermediary between the projector and the user's eyes. Instead of directly presenting multiple focal planes through complex optics, the system projects images to the retroreflector, which then returns the light with preserved focal information, simplifying the overall optical path.
2Adaptability or versatility
If conventional light field display techniques are used, then multiple planes of focus can be presented, but the brightness is reduced
Solution Approach 1:
The retroreflective screen creates virtual copies of the projected images at different focal planes, allowing the same light energy to be perceived as multiple images rather than dividing the light across multiple physical displays. This preserves brightness while creating multiple focal planes.
Solution Approach 2:
The system uses temporal multiplexing to present different focal planes at different times, with the retroreflector maintaining the optical path for each. By switching between focal planes rapidly, the system creates the perception of simultaneous multiple planes while using the full brightness of the light source for each plane sequentially.
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
The solution enhances the brightness and reduces complexity by allowing the user to focus on multiple images simultaneously, improving the accommodation to vergence matching, thus providing a more effective light field display experience.
Implementation Method 1
taking advantage of the phase conjugate reflection property of the retroreflective surface to preserve the focal difference
Data Source
AI summary
A projected head mounted display system is disclosed that projects images onto a retroreflective screen, which are then reflected back for view by a user. The projected head mounted display system displays computer generated images at multiple focal distances to simulate a light field so as to match eye accommodation to vergence.