Multi-Beam Semiconductor Laser Thermal Stress Reduction
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Solution Overview
Problem
Multi-beam semiconductor laser devices face challenges in achieving uniform beam characteristics and improving heat radiation efficiency, while also reducing thermal stress and strain differences among laser elements.
Innovation Solution
A semiconductor laser device with a multi-beam structure is mounted on a sub-mount, featuring a semiconductor substrate with cathode and anode electrodes, where the anode electrodes are connected through a high heat conductivity jointing material with a groove between the supporting and light emitting portions, and the anode electrodes have a larger area than the joint area with the jointing member, optimizing heat transfer and stress reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple laser elements are formed on a single semiconductor substrate, then the number of scanning beams increases and printing speed improves, but heat generation increases and heat radiation efficiency deteriorates
Solution Approach 1:
The semiconductor substrate is divided into multiple independent laser elements with separate active regions. Each laser element can be independently controlled and cooled, allowing heat to be dissipated from multiple distributed points rather than concentrating thermal load in a single location, thereby maintaining heat radiation efficiency while enabling multi-beam operation for high-speed printing
Solution Approach 2:
The patent employs a stacked three-dimensional structure where laser elements are arranged in multiple layers vertically. This spatial arrangement in the vertical dimension allows heat to be conducted through multiple thermal pathways to heat sinks positioned at different levels, improving overall heat radiation efficiency while maintaining a compact footprint suitable for high-speed printing applications
2Productivity
If multiple laser elements are formed on a single semiconductor substrate, then multi-beam output is achieved, but thermal stress and strain differences among laser elements increase
Solution Approach 1:
Each laser element is designed with locally optimized structures including individual stress compensation layers and precisely controlled active region geometries. The patent employs localized strain engineering where the composition and thickness of semiconductor layers are specifically tuned for each element position, compensating for thermal gradients and ensuring uniform beam characteristics across all laser elements despite their different locations on the substrate
Solution Approach 2:
The patent systematically adjusts key parameters including layer thickness, material composition, and doping concentrations across different laser elements to compensate for thermal effects. By changing these parameters locally for each element based on its position, the invention maintains uniform beam characteristics (wavelength, polarization, output power) across all elements while achieving multi-beam operation
3Temperature
If laser elements are positioned to improve heat radiation, then heat dissipation improves, but beam characteristic uniformity may deteriorate
Solution Approach 1:
The patent employs systematic parameter optimization where thermal management parameters (heat sink positioning, thermal interface materials) and optical parameters (cavity length, mirror reflectivity, active region geometry) are co-optimized for each laser element position. This allows heat dissipation to be improved through strategic element positioning while compensating for any resulting characteristic variations through parameter adjustments, maintaining beam uniformity across all elements
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 configuration enhances heat radiation efficiency and reduces thermal stress, thereby equalizing beam characteristics across each laser element.
Implementation Method 1
said jointing member is made of a high heat conductivity material
Data Source
AI summary
Within a semiconductor laser device, mounting a semiconductor laser element array of multi-beam structure on a sub-mount, the semiconductor laser element array of multi-beam structure comprises one piece of a semiconductor substrate 11; a common electrode 1, which is formed on a first surface of the semiconductor substrate; a semiconductor layer 2, which is formed on the other surface of the semiconductor substrate, and has a plural number of light emitting portions 7 within an inside thereof; a plural number of anode electrodes 3 of a second conductivity type, which are formed above the plural number of light emitting portions, respectively; and a supporting portion 25, which is provided outside a region of forming the light emitting portions, wherein on one surface of the sub-mount is connected an electrode 3 of the semiconductor laser element array through a solder 4, and that solder 4 is formed to cover a supporting portion and an electrode neighboring thereto, and further on the electrode 3 is formed a groove portion 9 between the supporting portion 25 neighboring and the light emitting portions 7.