Beam Combining Architectures for Laser Scanning Displays
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Solution Overview
Problem
Commercially available semiconductor laser light sources for scanning display systems have high threshold excitation levels, leading to wasted energy due to below-threshold excitation and insufficient illumination power at the dimmer end of their dynamic range.
Innovation Solution
A display system with an optical engine featuring two sets of laser light sources, where the first set has a higher threshold excitation level and outputs higher intensity laser light, and the second set has a lower threshold excitation level and outputs lower intensity laser light, combined using dichroic beam splitters to achieve angular separation and improved dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single set of semiconductor laser light sources with high threshold excitation levels is used, then sufficient illumination power is achieved, but energy is wasted due to below-threshold excitation and the dynamic range at the dimmer end is limited
Solution Approach 1:
The patent divides the laser light source system into two separate sets: a first set with high threshold excitation levels for high-intensity illumination, and a second set with low threshold excitation levels for low-intensity illumination. This segmentation allows each set to operate in its optimal intensity range, preventing energy waste from operating high-threshold lasers at low intensities while maintaining sufficient illumination power when needed.
Solution Approach 2:
The patent applies local quality by matching different laser sets to different intensity requirements within the system. The high-threshold laser set is used specifically for high-intensity applications, while the low-threshold laser set is used for low-intensity applications. This localized optimization ensures that each part of the system operates with appropriate characteristics for its specific function, improving overall energy efficiency.
2Reliability
If a single set of semiconductor laser light sources operates above threshold excitation level, then lasing is achieved, but the ability to operate at the dimmer end of the dynamic range is limited
Solution Approach 1:
The patent segments the laser operation into two distinct modes using two different laser sets. The first set of lasers operates above threshold for reliable high-intensity lasing, while the second set operates at or above its lower threshold for stable low-intensity lasing. This segmentation enables the system to access the full dynamic range from dim to bright while maintaining reliable lasing operation in both regimes.
Solution Approach 2:
The patent implements dynamic adaptability by allowing the system to switch between different laser sets based on the required intensity level. The controller can dynamically select which laser set to use, enabling the system to adapt to varying illumination requirements across the full dynamic range while maintaining stable lasing operation appropriate for each intensity regime.
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 system achieves improved energy efficiency and expanded dynamic range by utilizing laser light sources with lower threshold excitation levels, allowing for stable low-intensity light production and meeting the illumination requirements of scanning display systems.
Implementation Method 1
combined using dichroic beam splitters to achieve angular separation and improved dynamic range
Data Source
AI summary
Systems, devices, and methods for accommodating multiple sets of laser light sources in an optical engine of a display system such as a laser projection system are described. Laser light beams may be combined via wavelength-, polarization-, and/or angular-separation-based techniques. First and second sets of laser light beams may be angularly separated such that different sets of partially overlapping pixels are projected by the system, thereby increasing the display pixel density and/or an expanding the field of view of the display. One or more laser die may be mounted to each submount of the optical engine. For embodiments with two laser dies on each submount, collimating lenses may introduce angular separation between laser light beams output by each pair of commonly mounted laser dies. A retroreflector prism may be disposed at a beam combiner to provide a compact extension of the optical path through the beam combiner.