Waveguide Non-Common Pupil Arrangement for Compact Displays
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Solution Overview
Problem
Conventional waveguides used in displays expand image-bearing light in a single dimension, leading to increased height and mass, which is undesirable for applications like head-worn devices where reduced mass and size are favorable.
Innovation Solution
The use of a non-common pupil arrangement in the waveguide optics, where the vertical field angles are directed to a positionally displaced waist point, allowing the waveguide to converge and diverge in a way that reduces the minimum height and enables the removal of unnecessary material, resulting in a bow-tie or hourglass shape, and the implementation of folded prismatic collimating devices to manage optical power and reduce size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional waveguides expand image-bearing light in a single dimension, then the field of view is maintained, but the height and mass of the waveguide increase
Solution Approach 1:
The patent transitions from single-dimension expansion to two-dimension expansion by implementing a non-common pupil arrangement where vertical field angles are directed to a positionally displaced waist point. This allows the waveguide to expand image-bearing light in both horizontal and vertical dimensions simultaneously, maintaining a wider field of view while reducing the need for excessive height and mass
Solution Approach 2:
The waveguide is divided into distinct functional regions: an input coupling region for receiving collimated light, a propagation region with non-common pupil arrangement for two-dimensional expansion, and an output coupling region for delivering the expanded beam. This segmentation allows each region to be optimized independently, reducing overall waveguide mass while maintaining field of view performance
2Adaptability or versatility
If conventional waveguides expand image-bearing light in a single dimension, then the field of view is maintained, but the height of the waveguide increases
Solution Approach 1:
By implementing two-dimensional expansion through non-common pupil arrangement, the waveguide achieves wider field of view without proportionally increasing height. The vertical field angles are managed through positional displacement of the waist point rather than through vertical height increase, effectively decoupling field of view from height requirements
Solution Approach 2:
The patent changes the optical parameters by introducing a non-common pupil arrangement where the waist point is positionally displaced. This parameter change allows the waveguide to achieve the same or better field of view with reduced height by altering how light propagates and expands within the waveguide structure
3Weight of stationary object
If material is removed to reduce waveguide mass, then the waveguide becomes more compact, but structural integrity and optical performance may be compromised
Solution Approach 1:
The waveguide structure implements local quality by having different regions with different material densities or compositions. The core propagation region maintains full material integrity for optimal optical performance, while peripheral or less critical regions may have reduced material presence. This allows mass reduction without compromising the optical performance of critical regions
Solution Approach 2:
The waveguide may utilize composite material structures combining different materials with complementary properties. High-refractive-index materials are used in critical optical paths to maintain performance, while lower-density materials are used in non-critical regions for mass reduction. This composite approach maintains optical reliability while achieving mass and compactness goals
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 reduces the vertical size of the waveguide while maintaining the field of view, minimizing material usage and mass, and allows for efficient expansion of image-bearing light in both horizontal and vertical dimensions, enhancing the performance and compactness of display systems.
Implementation Method 1
waveguide comprises an input coupling region configured to receive collimated light and expand the light in a first dimension; a propagation region extending in a second dimension orthogonal to the first dimension, wherein a non-common pupil arrangement is implemented such that vertical field angles are directed to a positionally displaced waist point located past the input coupling region
Implementation Method 2
implementation of folded prismatic collimating devices to manage optical power and reduce size
Implementation Method 3
folded prismatic collimating devices
Data Source
AI summary
A waveguide to expand image bearing light in at least one dimension is disclosed. The waveguide comprises: an input coupling region configured to couple and input image bearing light into the waveguide; and an output coupling region comprising at least a first microstructure to the expand image bearing light in the first dimension, and output the image bearing light. A first waist point of the image bearing light in a first axis is located at a different location in the waveguide than a second waist point of the image bearing light in a second axis in the waveguide, the second axis orthogonal to the first axis.FIG. 4b to be published with the application.