AR Waveguide Diffractive Elements Field of View
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Solution Overview
Problem
Current augmented reality (AR) and virtual reality (VR) optical display systems face limitations such as bulkiness, restricted field of view (FOV), high angular selectivity, and the inability to address vergence-accommodation conflict, leading to user discomfort and reduced effectiveness for long-term use.
Innovation Solution
The development of a diffraction-enhanced optical display system that uses a single waveguide to maximize light coupling, correct wavelength dispersion, and provide beam divergence, allowing for a wide FOV and natural eye accommodation, while minimizing size and weight, using a combination of diffractive and refractive elements to expand the exit pupil and adjust perceived distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If diffractive optical elements are used to reduce size and weight, then device compactness is improved, but field of view is limited due to high angular selectivity
Solution Approach 1:
The patent combines multiple diffractive optical elements with different diffraction characteristics within a single optical waveguide system. This merging approach allows the system to achieve both compact size and wide field of view by utilizing the complementary strengths of different diffractive elements with varying angular selectivity profiles.
Solution Approach 2:
The patent introduces wavelength multiplexing as an additional dimension to overcome the angular selectivity limitation. By encoding multiple wavelength channels, each with different angular characteristics, the system effectively expands the field of view without increasing the physical size of the device.
2Adaptability or versatility
If reflective optical elements are used to operate at all RGB wavelengths, then wavelength coverage is improved, but device bulkiness increases
Solution Approach 1:
The patent replaces traditional reflective optical elements with diffractive optical elements that achieve wavelength-independent operation through diffraction physics rather than reflection. This substitution eliminates the need for bulky reflective coatings and multi-layer structures while maintaining broad spectral coverage.
Solution Approach 2:
The patent changes the operational parameter from reflection-based wavelength selection to diffraction-based wavelength management. By controlling diffraction grating parameters such as period and orientation, the system achieves broad wavelength coverage in a compact form factor.
3Productivity
If bulk optical systems with prisms are used to magnify and distribute images, then image distribution is improved, but device weight and size increase
Solution Approach 1:
The patent replaces bulk optical prism systems with waveguide-based optical distribution. The waveguide utilizes total internal reflection and diffractive coupling to achieve image magnification and distribution without the heavy glass prisms and complex mechanical alignment systems required by traditional bulk optics.
Solution Approach 2:
The patent employs thin waveguide films to replace thick prism assemblies. The waveguide's thin film structure enables image distribution and magnification functions with minimal weight and thickness while maintaining optical performance.
4Adaptability or versatility
If diffractive elements with complex shapes are used to achieve wide FOV, then field of view is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the wide field of view requirement into multiple discrete diffractive optical elements, each with simpler, more manufacturable geometries. By dividing the overall function into manageable segments, the system achieves wide FOV performance while using elements that are easier to fabricate with standard semiconductor or glass processing techniques.
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 system achieves a wide field of view greater than 30 degrees, reduces user fatigue by aligning convergence and accommodation, and maintains image quality with reduced power requirements, enhancing the overall AR/VR experience.
Implementation Method 1
Light rays propagate through the waveguide by TIR
Implementation Method 2
Diffractive elements consist of periodic variations in the waveguide's refractive index
Implementation Method 3
The image generator projects light into a free-form prism and refraction at the surface provides the means to magnify the image
Data Source
AI summary
Optical display systems and methods for providing three-dimensional and two-dimensional convergence corrected images to a user are described. The optical display systems may include at least two image generators producing a plurality of rays forming a plurality of images. A diffraction enhanced imaging system may be configured to collect the rays produced and control convergence angle of each ray at specific wavelengths into an optical waveguide. An in-coupling diffraction system may couple the rays into the optical waveguide. A wavelength compensated beam expander may expand horizontal extension of the images and an output coupling and vertical expansion system may magnify the images in a vertical direction and direct light towards a user at specific angles creating a wide field of view.