Laser Diodes with Scribe Structures for Stray Light Reduction
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Solution Overview
Problem
Existing optical devices, particularly lasers, suffer from inefficiencies in emitting blue and green light due to high energy storage properties and sensitivity to temperature, as well as issues with stray light leakage, which limits their deployment and performance.
Innovation Solution
The use of semi-polar or non-polar gallium containing substrates with trench structures on the backside to reduce stray light leakage, allowing for the emission of electromagnetic radiation in the blue and green spectrum, and incorporating a laser stripe region with cleaved facets for improved light guidance and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional lamp pumped solid state lasers or diode pumped solid state lasers are used to generate blue and green light, then the laser output can be achieved, but the wall plug efficiency remains low (1-10%) and the devices are large, expensive, and fragile
Solution Approach 1:
The patent extracts and eliminates the intermediate frequency conversion crystals from the laser system. By using direct blue and green emitting laser diodes, the invention removes the 808nm pump laser, 1064nm gain crystal, and frequency conversion crystal components, achieving high efficiency without the complex multi-stage conversion process that characterized traditional DPSS lasers
Solution Approach 2:
Instead of using infrared laser diodes with frequency conversion crystals to generate blue/green light (the traditional approach), the patent inverts the approach by directly using blue and green emitting laser diodes. This reversal eliminates the need for intermediate conversion steps and achieves superior efficiency and compactness
2Use of energy by moving object
If high power diode lasers are used to improve efficiency, then wall plug efficiency increases to 5-10%, but the lasers require precise temperature controls and have substantial size and power consumption
Solution Approach 1:
The patent applies local quality by implementing temperature control only where absolutely necessary - specifically for the 808nm pump laser diode if used. The blue and green emitting laser diodes themselves require minimal temperature control, allowing the system to achieve high efficiency with reduced thermal management complexity compared to traditional DPSS lasers that require precise temperature control of multiple components
3Ease of manufacture
If conventional laser structures without trench structures are used, then the device is simpler to manufacture, but stray light leakage occurs which reduces performance
Solution Approach 1:
The patent converts the potentially harmful stray light that would normally leak from the backside of the substrate into a beneficial feature by using trench structures to contain and redirect it. The trenches transform what would be waste light into useful output, improving overall efficiency without adding complex external optical elements
Solution Approach 2:
The patent segments the substrate backside by creating multiple trench structures that divide the space into controlled regions. These segmented trenches act as individual light containment channels, collectively preventing stray light leakage while maintaining manufacturing simplicity through standard semiconductor fabrication techniques
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 cost-effective, high-performance optical devices capable of efficient blue and green light emission with reduced leakage and interference, enhancing their applicability and stability.
Implementation Method 1
multiple trench structures that reduce stray light leaking
Implementation Method 2
multiple trench structures that reduce stray light leaking
Implementation Method 3
laser stripe region with cleaved facets for improved light guidance
Data Source
AI summary
A method and device for emitting electromagnetic radiation using semipolar or nonpolar gallium containing substrates is described where the backside of the substrate includes multiple scribes that reduce stray light leaking.