Micro-LED Beam Tuning With Optical Deflection for Uniform Near-Eye Displays
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Solution Overview
Problem
Existing near-eye displays using micro-LEDs face challenges in achieving high coupling efficiency and uniform intensity distribution of light beams due to large angular emission profiles and limited field of view, leading to ghost images and non-uniform brightness.
Innovation Solution
The use of an array of optical elements, such as micro-lenses or prisms, to deflect light beams at angles different from the chief ray angles, based on beam profiles and micro-LED positions, improving the coupling efficiency and uniformity by displacing micro-lenses relative to micro-LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If micro-LEDs are used with large angular emission profiles, then the field of view is limited, but the coupling efficiency and intensity uniformity deteriorate
Solution Approach 1:
The patent applies local quality by using an array of optical elements where each element is positioned and oriented specifically to handle light from its corresponding micro-LED. Each optical element has customized parameters (position, orientation, shape) optimized for the local light emission characteristics of its associated micro-LED, transforming the broad angular emission into a directed beam while maintaining uniform intensity across the entire display array.
Solution Approach 2:
The array of optical elements serves as an intermediary between the micro-LEDs and the final display output. These optical elements mediate the light transformation process by receiving the broad angular emission from micro-LEDs and converting it into directed beams with controlled angular profiles, thereby improving coupling efficiency without limiting the overall field of view.
2Productivity
If light beams are emitted at chief ray angles, then the optical path is straightforward, but the coupling efficiency and beam profile control are insufficient
Solution Approach 1:
The patent segments the optical control function by using an array of discrete optical elements, each independently positioned and oriented to handle specific portions of the light emission from corresponding micro-LEDs. This segmentation allows precise control over the angular distribution of light from each micro-LED, optimizing coupling efficiency while managing the overall system complexity through modular, repeatable units.
Solution Approach 2:
The optical elements are positioned and oriented at specific angles relative to the micro-LEDs, creating a dynamic optical path that adapts to the emission characteristics of each micro-LED. This dynamic arrangement allows the system to optimize light coupling by adjusting the angular orientation of optical elements to match the specific beam profiles and emission angles of individual micro-LEDs.
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
Enhances light coupling efficiency and intensity uniformity across the display, reducing ghost images and non-uniform brightness, thereby improving the overall display quality.
Implementation Method 1
An optical element of the array of optical elements may be configured to deflect a light beam emitted by a micro-LED of the array of micro-LEDs at a deflection angle that is greater than 0° and is smaller than 90% of a chief ray angle from the micro-LED
Data Source
AI summary
A near-eye display includes a light source including an array of micro light emitting diodes (micro-LEDs) configured to emit light beams, display optics configured to project the light beams emitted by the array of micro-LEDs to a user's eye, and an array of optical elements between the array of micro-LEDs and the display optics. The array of optical elements is configured to extract and direct the light beams emitted by the array of micro-LEDs towards the display optics. An optical element of the array of optical elements is configured to deflect a light beam emitted by a micro-LED of the array of micro-LEDs at a deflection angle that is greater than 0° and is smaller than the chief ray angle from the micro-LED.