VCSEL Array Beam Combining for Mirrorless Digital Laser Displays
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Solution Overview
Problem
Existing laser display technologies are inefficient, bulky, and energy-wasting, relying on mechanical mirrors and analog power sources, and produce scintillation effects and require expensive, non-scalable systems for color generation.
Innovation Solution
A system using VCSEL arrays with digitally defined current drive inputs, combining multiple VCSELs in sub-arrays controlled by binary strings to generate coherent or incoherent light beams for high-resolution color display without mechanical mirrors, reducing energy consumption and scintillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If mechanical mirrors and analog power sources are used for laser beam control, then color intensity can be adjusted, but the system becomes bulky and energy-consuming
Solution Approach 1:
The patent replaces mechanical mirrors with acousto-optic modulators (AOMs) that use acoustic waves to diffract and modulate laser beams. This substitution eliminates bulky mechanical components while maintaining the ability to control beam intensity and direction through electrical signals, directly resolving the contradiction between color intensity control and system size.
Solution Approach 2:
The patent uses analog power source variation to control laser diode output intensity, which is then converted to digital signals for precise control. By changing the operating parameters of the laser diodes and using PWM (pulse-width modulation) techniques, the system achieves accurate color intensity control without requiring large mechanical mirror assemblies, thus reducing system complexity while maintaining illumination control capability.
2Illumination intensity
If white light sources are filtered to generate colors, then color generation is possible, but energy is wasted and heat is produced
Solution Approach 1:
The patent segments the white light source into three separate color channels (red, green, blue) using dichroic beam splitters and filters. Each color component is independently controlled by its own laser diode and AOM, allowing precise energy utilization. This segmentation enables the system to generate only the specific colors needed rather than filtering a broad spectrum, significantly reducing energy waste and heat production.
Solution Approach 2:
The patent implements local quality control by using separate laser diodes for each color channel (red, green, blue) with specific wavelengths. Each color channel has its own optimized laser diode and control circuitry, allowing independent optimization of energy efficiency for each color. This local quality approach eliminates the need to generate and filter unnecessary wavelengths, reducing overall energy consumption and heat generation.
3Illumination intensity
If edge-emitting semiconductor lasers are used, then correct color output is achieved, but photo-lithographically arrayed designs are limited
Solution Approach 1:
The patent inverts the conventional approach by using vertical-cavity surface-emitting lasers (VCSELs) instead of edge-emitting lasers. VCSELs emit light perpendicular to the substrate surface, which is ideal for photolithographically arrayed designs where multiple lasers can be fabricated in parallel on a single wafer. This inversion of the emission direction enables scalable manufacturing while maintaining precise color output through wavelength-specific laser diodes.
4Illumination intensity
If VCSELs with extreme power requirements are used, then green output wavelength is achieved, but reliability issues arise
Solution Approach 1:
The patent optimizes the operating parameters of VCSELs to achieve green output wavelength (around 532nm) while maintaining reliability. By carefully controlling the drive current, pulse width, and duty cycle of the VCSELs, and using PWM modulation techniques, the system achieves the required green light output without subjecting the VCSELs to extreme power conditions that would cause reliability issues. The use of AOMs also allows for rapid on/off switching, reducing thermal stress on the VCSELs.
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 enables high-bandwidth, bright, and compact laser displays with reduced scintillation, minimizing the need for analog-to-digital circuitry and allowing for smaller, more efficient thermal management.
Implementation Method 1
a lens array positioned over the set of the one or more semiconductor light devices and configured to focus the plurality of light beams to a single focal point
Implementation Method 2
a macro lens, wherein a focal point of the macro lens is positioned at the single focal point and configured to collimate the plurality of light beams at the single focal point into the single light beam
Data Source
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AI summary
Embodiments comprise laser emitter devices that generate a collimated beam of light the intensity or amplitude of which may be varied so as to carry data signals at a high rate of efficiency, and that is less sensitive to alignment of the detector, and detector systems for detecting the same collimated beam and reading the data carried in the beam of light.