Multi-Emitter Light Source for Scanning Projector Displays
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Solution Overview
Problem
Existing scanning projector displays for head-mounted displays face challenges in achieving compactness and efficiency due to the need for larger beam sizes for better optical quality, which requires larger and slower scanners, and simultaneous scanning in both horizontal and vertical directions results in tilted scanning lines that can lead to image artifacts and inefficiencies.
Innovation Solution
A scanning projector display using a multi-emitter light source with emitters spaced apart to energize non-adjacent pixels, employing a controller to coordinate scanning and power variations across non-parallel axes, enabling faster and more efficient scanning with bidirectional and interlaced scanning configurations to avoid image shift and artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single light source is used for scanning projector display, then the device structure is simple, but the scanning speed is slow and the display size/weight is large
Solution Approach 1:
The single light source is segmented into multiple emitters (N>1) that operate simultaneously. Each emitter contributes to scanning different portions of the display area, enabling parallel scanning operations that increase overall scanning speed while distributing the computational and optical load across multiple independent light-generating elements.
Solution Approach 2:
Multiple emitters are combined into a unified light engine system that shares common control electronics and scanning coordination. The emitters work in concert with synchronized timing signals to produce a cohesive display output, merging their individual contributions into a unified high-speed scanning system.
2Area of stationary object
If emitters are spaced closely to cover adjacent pixels, then the spatial coverage is complete, but neighboring emitters interfere with each other causing image artifacts
Solution Approach 1:
Each emitter is assigned a specific spatial responsibility zone rather than attempting uniform coverage. The spacing between emitters is optimized so that each emitter illuminates a distinct set of pixels with appropriate intensity distribution, creating local optimization that prevents overlap interference while maintaining complete area coverage through coordinated operation.
Solution Approach 2:
The system dynamically coordinates the activation and intensity modulation of multiple emitters based on real-time scanning requirements. By controlling which emitters are active at specific moments and adjusting their power levels dynamically, the system ensures that emitters do not simultaneously illuminate the same pixel region, thereby preventing interference artifacts while maintaining continuous pixel coverage.
3Productivity
If scanning is performed in a fixed direction only, then the scanning mechanism is simple, but the display updates are slow and less efficient
Solution Approach 1:
The scanning system employs periodic bidirectional scanning cycles that alternate between upward and downward (or leftward and rightward) directions. This periodic reversal allows the scanner to cover the entire display area more efficiently by utilizing both forward and return trips for productive scanning, effectively doubling the update rate compared to unidirectional scanning while maintaining relatively simple scanner hardware.
Solution Approach 2:
The controller pre-coordinates the timing and sequencing of multiple emitters before the actual scanning operation begins. By establishing the scanning pattern, emitter activation sequence, and synchronization timing in advance, the system optimizes the scanning trajectory and emitter coordination to achieve maximum display update efficiency without requiring complex real-time adjustments during scanning.
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 allows for faster scanning with improved energy efficiency and image quality, reducing the size and weight of the display while minimizing image artifacts, enabling a more comfortable and immersive VR/AR experience.
Implementation Method 1
a light engine having N emitters coupled to a collimator for providing a fan of N light beams of variable optical power levels
Implementation Method 2
A scanner is configured to receive and angularly scan the fan of N light beams about first and second non-parallel axes
Data Source
AI summary
A scanning projector display includes a light engine comprising N emitters coupled to a collimator for providing a fan of N light beams of variable optical power levels, where N>1. The N emitters are spaced apart from each other such that pixels of the image simultaneously energized by neighboring ones of the N emitters are non-adjacent. A scanner receives and angularly scans the fan of N light beams about first and second non-parallel axes to provide an image in angular domain. A controller coupled to the scanner and the light engine causes the scanner to simultaneously scan the fan of N light beams about the first and second axes, and cause the light engine to vary the optical power levels of the N emitters with time delays such that adjacent pixels of the image are energized by different ones of the N emitters.