Laser Assembly With Photothyristor Segmentation For Defect Decoupling
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Solution Overview
Problem
The production of laser bars using AlInGaN material system is impaired by high defect density, leading to low yield and reduced efficiency due to non-functional emitters, which heat up and reduce overall performance, and there is a lack of available laser bars with emission wavelengths between 350 nm and 590 nm that can achieve the required high optical output powers for applications like projection and material processing.
Innovation Solution
A laser arrangement that integrates photothyristors with semiconductor lasers, allowing for electrical separation of defective emitters and optical coupling to prevent current flow, enabling efficient operation and high output power while maintaining similar emission properties across the laser bar.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If semiconductor lasers are produced using AlInGaN material system, then laser radiation in wavelength range 350 nm to 590 nm can be generated, but high defect density leads to low yield and reduced efficiency
Solution Approach 1:
The patent divides the laser bar into multiple laser groups, each with its own photothyristor for independent control. This segmentation allows defective emitters to be isolated and electrically decoupled without affecting the entire laser bar, thereby maintaining high yield despite defects in AlInGaN material system
Solution Approach 2:
Photothyristors are introduced as intermediary components between the electrical contact and each laser group. These photothyristors act as optical switches that can electrically decouple defective emitters when they fail to emit sufficient light, preventing them from reducing overall efficiency while maintaining the desired wavelength range
2Ease of operation
If all emitters in a laser bar are electrically connected in parallel, then current can flow to all emitters, but defective emitters heat up and reduce overall performance
Solution Approach 1:
The patent segments the electrical connection structure by inserting photothyristors into each laser group's electrical path. This allows selective electrical decoupling of defective emitters that would otherwise heat up and reduce performance, while maintaining simple parallel connection for functional emitters
Solution Approach 2:
The photothyristors automatically detect and respond to defective emitters through optical feedback. When an emitter fails to produce sufficient light, the associated photothyristor stops conducting current to that group, preventing heat generation without requiring external monitoring or control systems
3Reliability
If photothyristors are integrated into the semiconductor layer sequence, then electrical decoupling of defective emitters is achieved, but device complexity increases
Solution Approach 1:
The patent merges the photothyristor structure with the semiconductor laser layers, integrating the switching function directly into the laser bar's epitaxial structure. This reduces the need for separate external switching components and simplifies the overall device architecture despite the added functionality
Solution Approach 2:
The photothyristors serve multiple functions: they act as electrical switches to decouple defective emitters, provide optical feedback monitoring, and maintain electrical connection for functional emitters. This multi-functionality reduces the need for additional separate components, offsetting the structural integration complexity
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 integration of photothyristors in the semiconductor layer sequence allows for effective electrical decoupling of defective emitters, reducing heat issues and enhancing the efficiency of the laser bar, enabling high optical output powers and simplifying handling, while also addressing the lack of suitable laser bars in the desired wavelength range.
Implementation Method 1
A laser arrangement 1 comprises a plurality of laser groups 2. Each of the laser groups 2 comprises one or more semiconductor lasers 20. The laser arrangement 1 comprises a plurality of photothyristors 3 so that each of the laser groups 2 is uniquely assigned to one of the photothyristors 3. The photothyristors 3 are each optically coupled to the associated laser group 2.
Implementation Method 2
A photothyristor, as well as a normal thyristor, has a voltage-dependent resistance. Above a breakdown voltage, the photothyristor is electrically conductive, but only poorly conductive below the breakdown voltage. In the case of a photothyristor, the breakdown voltage additionally depends on an illumination intensity.
Data Source
AI summary
The invention relates to a laser assembly, wherein, in one embodiment, the laser assembly (1) comprises a plurality of laser groups (2) each having at least one semiconductor laser (20). Furthermore, the laser assembly (1) contains a plurality of photothyristors (3), each laser group (2) being clearly assigned one of the photothyristors (3). The photothyristors (3) are each connected electrically in series with the associated laser group (2) and/or integrated in the associated laser group (2). Furthermore, the photothyristors (3) are each optically coupled to the associated laser group (2). A dark breakdown voltage (Ut) of each photothyristor (3) lies above an intended operating voltage (Ub) of the associated laser group (2).