Semiconductor Laser Light Source With Waveplate Polarization Alignment
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Solution Overview
Problem
Light emitting devices with multiple semiconductor laser elements face increased beam divergence angles as beam path length increases, leading to reduced optical efficiency and misalignment issues due to differing polarization directions and beam divergence characteristics.
Innovation Solution
A light emitting device comprising a base, first and second semiconductor laser elements with different polarization directions, a lens member, and a waveplate to change the polarization direction of the first semiconductor laser element's light, which is then combined with the second semiconductor laser element's light to reduce beam divergence and align polarization, using a specific configuration of light reflecting members and lens parts to control the beam path and output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the beam path length is increased by interposing light reflecting members, then the optical system can be designed with more flexibility in traveling direction and emission region, but the beam divergence angle increases leading to reduced optical efficiency
Solution Approach 1:
A waveplate is introduced as an intermediary optical element between the semiconductor laser element and the lens. The waveplate converts the polarization state of the laser beam, enabling more flexible optical path design while maintaining beam quality and reducing divergence effects through optimized polarization control in the optical system.
Solution Approach 2:
The patent changes the polarization parameter of the light beam by using a waveplate to transform linearly polarized light into circularly polarized light or change the polarization direction. This parameter transformation allows the optical system to achieve better performance with extended beam paths by optimizing how light interacts with subsequent optical elements, thereby reducing effective beam divergence.
2Adaptability or versatility
If multiple semiconductor laser elements with different polarization directions are used, then more versatile light output can be achieved, but misalignment issues occur due to differing polarization directions
Solution Approach 1:
The waveplate serves as a universal polarization control element that can process light from multiple semiconductor laser elements with different polarization directions. By placing the waveplate in the common optical path, it uniformly transforms the polarization state of beams from different sources, enabling versatile multi-color or multi-directional light output while maintaining precise alignment through standardized polarization control.
3Loss of energy
If a waveplate is added to change polarization direction, then beam divergence can be reduced and optical efficiency improved, but device complexity increases
Solution Approach 1:
The waveplate is designed to be self-aligning through polarization-dependent mounting structures or adhesive patterns that automatically orient the fast and slow axes of the waveplate correctly during assembly. This self-service alignment mechanism reduces the need for complex adjustment mechanisms and precision alignment tools, thereby limiting the increase in device complexity while maintaining the optical efficiency benefits.
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 solution effectively reduces beam divergence angles and aligns polarization directions, enhancing optical efficiency and reducing misalignment issues, allowing for more focused and efficient light output in compact designs suitable for applications like head-mounted displays and projectors.
Implementation Method 1
The waveplate is configured to change the polarization direction of light from the first semiconductor laser element
Implementation Method 2
The lens member is a member into which light beams from the first semiconductor element and the second semiconductor laser element enter
Implementation Method 3
the beam path lengths reaching the lenses can be increased by interposing light reflecting members, such as mirrors or prisms
Data Source
AI summary
A light emitting device includes a base, a first semiconductor laser element, a second semiconductor laser element, a lens member, and a waveplate. The base has a bottom part. The first semiconductor laser element is disposed on the bottom part of the base. The second semiconductor laser element is disposed on the bottom part of the base. The second semiconductor laser element has a different polarization direction from a polarization direction of the first semiconductor laser element. The lens member is a member into which light beams from the first semiconductor element and the second semiconductor laser element enter. The waveplate is configured to change the polarization direction of light from the first semiconductor laser element.