Near Eye Display Projector Optical Path Folding
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Solution Overview
Problem
Conventional near eye display systems, such as augmented reality (AR) and virtual reality (VR) headsets, become bulky and uncomfortable due to the large size and weight of the projector and optical components, leading to strain on the nose and ear areas when worn for extended periods.
Innovation Solution
A compact in-line optical projector system is integrated with a transmissive lens, utilizing an optical folding element to fold the light path at least twice, reducing the thickness and weight of the projector, and mounting it above the field of view, with an optical folding element coupling the projector output to the waveguide input, allowing for a thinner and more comfortable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional projector and optical components are used in near eye display systems, then the display functionality is achieved, but the system becomes bulky and heavy causing strain on nose and ear areas
Solution Approach 1:
The patent applies dimensionality change by folding the optical path multiple times within a compact volume, transforming a linear light path into a multi-dimensional folded configuration. This allows the projector to achieve a thin form factor while maintaining the necessary optical component spacing and light propagation distance, directly resolving the contradiction between display functionality and wearability comfort.
2Ease of operation
If conventional projector and optical components are used in near eye display systems, then the display functionality is achieved, but the system becomes bulky causing discomfort for extended wear
Solution Approach 1:
The patent employs optical path folding that utilizes three-dimensional space efficiently by bending the light path at multiple angles (e.g., 45-degree mirrors, prisms). This transforms a volumetrically large linear arrangement into a compact folded configuration, reducing the projector volume to fit within wearable form factors while preserving all necessary optical functions.
Solution Approach 2:
The patent integrates optical components in a nested or layered arrangement where elements are positioned in overlapping or adjacent planes. The folded optical path allows components to be nested within the same physical envelope, maximizing space utilization and minimizing the overall projector volume for comfortable extended wear.
3Length of moving object
If optical path is folded multiple times, then the projector thickness is reduced, but the optical path length and component arrangement complexity increases
Solution Approach 1:
The patent segments the optical path into distinct functional sections (illumination, modulation, projection, folding) with dedicated optical elements for each segment. This modular segmentation allows independent optimization of each section while managing overall complexity, making the folded design more tractable and manufacturable.
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 provides a comfortable and wearable near eye display system that reduces strain on the nose and ears, enabling extended use without discomfort, while maintaining the functionality of AR and VR applications by integrating the projector within a thin form factor.
Implementation Method 1
an optical folding element optically coupled between the projector output and the waveguide input, the optical folding element configured to fold an optical path of the patterned light in at least two different directions
Implementation Method 2
an optical projector having a projector output, the optical projector comprising an optical prism element, a spatial light modulator and an illumination source, the illumination source optically coupled to the optical prism element and configured to provide illumination light into the optical prism element
Data Source
AI summary
A near eye display apparatus includes: a lens having a viewing area, the lens comprising a waveguide having a waveguide input and a waveguide output optically coupled to the viewing area; an optical projector having a projector output, the optical projector comprising an illumination source optically coupled to the optical prism element and configured to provide illumination light into the optical prism element at a particular direction, a spatial light modulator optically coupled to the optical prism element and configured to receive the illumination light from the optical prism element and to reflect patterned light, the optical prism element configured to provide the patterned light to the projector output at the particular direction; and an optical folding element optically coupled between the projector output and the waveguide input, the optical folding element configured to fold an optical path of the patterned light in at least two different directions.