Curved See-Through Lightguide With Intermediate Focus for Compact AR Optics
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Solution Overview
Problem
Conventional wearable electronic eyewear devices face limitations in field of view, thickness, optical aberrations, and aesthetics, hindering their adoption in consumer markets due to bulky designs and poor fashion appeal.
Innovation Solution
The use of a curved lightguide with an optics relay to form an intermediate image, reducing the size of the optical output system and minimizing aberrations by increasing magnification, while incorporating a reflective optical coating to enhance aesthetics and user experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lightguide is used to distribute light from a single source to multiple locations, then the number of light sources can be reduced, but the light intensity at each location decreases significantly
Solution Approach 1:
The patent transitions from linear light distribution to volumetric light distribution by creating an intermediate focus within the lightguide structure. This allows light to be concentrated at a specific point inside the waveguide before being distributed, effectively adding a spatial dimension to the light distribution process and maintaining higher intensity levels throughout the system.
Solution Approach 2:
The patent modifies the optical parameters of the lightguide by introducing a curved section with specific radius of curvature. This changes the light propagation characteristics, enabling total internal reflection to redirect light toward an intermediate focus point, thereby concentrating light energy at strategic locations rather than uniformly distributing it, which maintains higher intensity levels.
2Illumination intensity
If a curved section is added to the lightguide to create an intermediate focus, then light intensity distribution is improved, but the device complexity increases
Solution Approach 1:
The patent introduces a curved section in the lightguide with a specifically designed radius of curvature. This curvature enables the light to follow a controlled path that naturally focuses at an intermediate point without requiring additional optical components. The curved geometry itself becomes the focusing mechanism, simplifying the overall device while improving light distribution.
Solution Approach 2:
The patent combines the light guiding function and the light focusing function into a single integrated structure. The curved section of the lightguide simultaneously serves as both the light transmission medium and the focusing element, eliminating the need for separate lenses or mirrors. This merging of functions reduces device complexity while achieving improved light intensity distribution.
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 achieves a compact form factor and improved image quality by reducing unwanted interactions and diffraction, aligning with eyeglass and sunglass frame aesthetics, thus enhancing user experience.
Implementation Method 1
the curved section having a radius of curvature sufficient to redirect light through a curved section of the lightguide by total internal reflection
Implementation Method 2
a curved see-through lightguide with intermediate focus... a single light source positioned at a first end of the lightguide can be used to illuminate a number of different locations
Data Source
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AI summary
A head-mounted display includes a microdisplay configured to emit light representative of an image and provide the emitted light to an optics relay included in the head-mounted display. The optics relay is configured to magnify the image emitted by the microdisplay by a predetermined power such that an intermediate image based on the magnified image is formed in a curved lightguide of the head-mounted display. The intermediate image is then provided by the curved lightguide to an optical output system included in or otherwise coupled to the curved lightguide. The optical output system then provides at least a portion of the intermediate image to the eye of a user.