AR Microlens Projection Lens Uniform Bounce Length
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Solution Overview
Problem
Existing augmented reality (AR) systems suffer from decreased image quality due to nonuniform bounce lengths within the waveguide, which affects the uniformity and clarity of the projected light.
Innovation Solution
The proposed AR projection system includes a light engine with pixels and microlenses, where each pixel emits light with a specific spectrum and cone angle, and the projection lens refracts this light to match the pupil length, ensuring that the light is incoupled into the waveguide at a bounce length equivalent to the pupil length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light is projected through a waveguide in typical AR systems, then the light image can be displayed to the user, but the bounce lengths become nonuniform resulting in decreased image quality
Solution Approach 1:
The patent changes the optical parameters of the system by introducing a telecentric projection lens that modifies the light propagation characteristics. This lens ensures that light rays from each pixel traverse a uniform optical path length through the waveguide, transforming the nonuniform bounce lengths into uniform ones. The parameter change occurs in the optical path design, specifically in how light is coupled into and propagates through the waveguide, thereby resolving the contradiction between achieving image display and maintaining bounce length uniformity.
2Productivity
If a microlens is coupled to each pixel emission surface, then light can be effectively directed into the waveguide, but the system complexity increases
Solution Approach 1:
The patent merges the microlens array functionality with the projection lens into a single integrated telecentric projection lens assembly. Instead of treating the microlens array and projection lens as separate components, the design combines their functions into one unified optical element that performs both light collection from pixels and telecentric projection into the waveguide. This merging reduces the number of discrete components and simplifies the overall system structure while maintaining high light coupling efficiency.
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 solution maintains a uniform bounce length within the waveguide, enhancing the image quality and efficiency of the AR device by reducing ghost images and increasing the resolution of the projected light.
Implementation Method 1
a projection lens configured to refract a first light emitted by the pixel
Implementation Method 2
The waveguide reflects the light to an outcoupler where the waveguide outcouples the light image
Data Source
AI summary
Embodiments of the present disclosure generally relate to augmented reality (AR) systems. More specifically, embodiments described herein provide for an AR projection system and AR devices having the projection system. In one or more embodiments, an augmented reality device includes a projection system. The projection system includes a light engine. The light engine includes a pixel. The pixel includes an emission surface. A microlens is coupled to the emission surface of the pixel. The projection system further includes a projection lens configured to refract a first light emitted by the pixel. The first light has a first pupil length defined by a distance between a first end and a second end of the first light. The augmented reality device further includes a waveguide including an input coupler configured to incouple the first light at a first bounce length that is equivalent to the first pupil length.