Superluminous LED Array for Waveguide Display Coherence
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Solution Overview
Problem
Conventional near-eye-displays lack light sources that generate high-brightness image light with both spatial and temporal coherence, which is essential for achieving high brightness and wide field of view in augmented reality applications.
Innovation Solution
A waveguide display system incorporating a light source, scanning mirror assembly, and output waveguide, where the light source is a 1-D or 2-D array of Superluminous LEDs or modified VCSELs, and the scanning mirror assembly redirects image light onto the output waveguide to achieve spatial and temporal coherence, enabling high-brightness and wide-field-of-view imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LEDs are used as light sources, then the display provides a wide spectrum and good temporal coherence, but it lacks spatial coherence and high brightness
Solution Approach 1:
The light source is divided into an array of multiple SLEDs, each emitting light with specific spatial coherence properties. By segmenting the light source into discrete elements that can be individually controlled and positioned, the system achieves both high brightness through array combination and spatial coherence through precise geometric arrangement of each segment.
2Adaptability or versatility
If a single wavelength laser is used, then the display achieves high spatial and temporal coherence, but it lacks the wide spectrum needed for natural color display
Solution Approach 1:
Multiple SLEDs with different wavelengths (colors) are merged into a single array structure. Each SLED maintains its temporal coherence while the combination of multiple wavelength sources provides a wide spectrum. The merging of these coherent light sources at different wavelengths achieves both broad spectral coverage and preserved temporal coherence properties.
3Area of stationary object
If the light source is densely packed to increase brightness, then the field of view expands, but the complexity of the scanning mirror assembly increases
Solution Approach 1:
The light source is arranged in a two-dimensional array rather than a simple linear configuration. This dimensional change allows the system to expand the field of view in multiple directions simultaneously. The 2D array structure enables broader angular coverage while maintaining manageable complexity in the scanning mirror assembly through optimized geometric arrangement.
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 provides a high-brightness, spatially and temporally coherent image light, enhancing the display's ability to project clear and coherent images over a wide field of view, suitable for augmented reality applications.
Implementation Method 1
the light source is a 1-D linear array of Superluminous LEDs (SLEDs), where each SLED corresponds to a respective row in an image ultimately displayed to the user
Implementation Method 2
conventional LEDs lack a spatial coherency (i.e. a collimated beam of light)... conventional display designs in near-eye-displays lack light sources that generate an image light with very high brightness that has both spatial and temporal coherence
Implementation Method 3
The scanning mirror assembly includes one or more scanning mirrors that scan in one dimension along the linear array of SLEDs and redirects the image light onto an entrance location of the output waveguide
Implementation Method 4
The output waveguide receives the scanning image light emitted from the scanning mirror assembly at the input area, and output expanded image light from a portion of the output area
Data Source
AI summary
A waveguide display includes a light source, a scanning mirror assembly, an output waveguide, and a controller. The light source emits image light. The scanning mirror assembly scans the image light as scanned image light to particular locations in accordance with scanning instructions. The output waveguide includes an input area and an output area. The output waveguide receives the scanned image light emitted from the scanning mirror assembly at the input area, and output expanded image light from a portion of the output area, the location of the portion of the output area based in part on a direction of the scanned image light output from the scanning mirror assembly. The controller generates the scanning instructions and provides the scanning instructions to the scanning mirror assembly.