Variable-Pitch Micro-LED Color Display for High-Throughput AR Optics
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Solution Overview
Problem
Current augmented reality and mobile projection display systems using reflective liquid-crystal on silicon (RLCOS) technology suffer from low optical throughput and slow switching times due to bulky polarization optics and limited switching speeds, which restrict their ability to rapidly change between black and color states.
Innovation Solution
The use of micro-LED devices with variable pitch per color panel, eliminating the need for polarization optics and allowing for kHz switching speeds, combined with an X-cube combiner for optical combining of light from monochrome red, green, and blue panels, each with its own emitter pitch and resolution, to simplify the optics design and enhance power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If reflective liquid-crystal on silicon (RLCOS) display with polarization optics is used, then color display capability is achieved, but optical throughput is reduced due to high losses from polarization optical elements
Solution Approach 1:
The patent extracts and removes the polarization optics from the display system, transitioning from RLCOS technology to direct-view micro-LED technology. This elimination of polarization elements directly addresses the optical throughput loss problem while simplifying the overall device architecture.
Solution Approach 2:
The patent replaces the liquid-crystal-based RLCOS mechanical/optical system with a solid-state micro-LED system. This substitution eliminates the need for polarization optics and focusing elements, thereby reducing optical losses and simplifying the device structure.
2Speed
If reflective liquid-crystal on silicon (RLCOS) display is used, then color display capability is achieved, but switching speed is limited to 60-120 Hz
Solution Approach 1:
The patent replaces the liquid-crystal technology with solid-state micro-LED technology. This substitution enables switching speeds in the kHz range, dramatically improving the speed parameter while maintaining color display capability through direct emission from the LED elements.
3Manufacturing precision
If uniform pitch is used across all color panels, then manufacturing simplicity is maintained, but image quality is compromised due to inability to optimize emitter size per color
Solution Approach 1:
The patent applies different pitch values to different color panels (red, green, blue) based on the specific requirements of each wavelength. This local optimization allows larger emitters for red and blue panels while using smaller emitters for green panels, thereby improving overall image quality without requiring uniform pitch across all panels.
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 results in improved power savings, reduced system complexity and cost, and higher brightness with maintained image quality, as larger emitters can be used for red and blue panels while smaller green emitters provide high resolution, leveraging human vision's adaptability to green light for effective AR/VR/MR displays.
Implementation Method 1
Each panel may comprise a respective array of light emitters. The multiple lights may comprise a red light, a green light, and a blue light.
Data Source
AI summary
This disclosure relates to the use of variable-pitch light-emitting devices for display applications, including for displays in augmented reality, virtual reality, and mixed reality environments. In particular, it relates to small (e.g., micron-size) light emitting devices (e.g., micro-LEDs) of variable pitch to provide the advantages, e.g., of compactness, manufacturability, color rendition, as well as computational and power savings. Systems and methods for emitting multiple lights by multiple panels where a pitch of one panel is different than pitch(es) of other panels are disclosed. Each panel may comprise a respective array of light emitters. The multiple lights may be combined by a combiner.