Semiconductor Laser Wavelength Bandwidth Control for Color Stability
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Solution Overview
Problem
Semiconductor lasers oscillating in longitudinal multimode face challenges in preventing color shift during colored light generation, particularly in head-up display devices, due to large wavelength bandwidths and temperature dependencies, which affect color reproducibility.
Innovation Solution
A light source device utilizing semiconductor lasers with a narrowed wavelength bandwidth of ≤15 nm, where intensities ≥-20 dB relative to the peak, allows approximation to single wavelength oscillation, enabling stable color representation by estimating the proxy wavelength based on ambient and self-temperature dependencies, and adjusting emission light intensities accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If semiconductor laser oscillates in longitudinal multimode, then higher power output is achieved, but color shift occurs due to large wavelength bandwidth
Solution Approach 1:
The patent applies parameter changes by controlling the wavelength bandwidth to be 15 nm or less and managing the number of longitudinal modes to be 3 or fewer. This selective parameter control allows the system to maintain high power output while preventing color shift, as the narrow bandwidth ensures stable color representation even in multimode operation
Solution Approach 2:
The patent implements dynamics through temperature control mechanisms that actively manage the semiconductor laser's operating conditions. By controlling temperature variations, the system maintains stable wavelength characteristics and prevents color shift while preserving high power output capability
2Power
If semiconductor laser oscillates in longitudinal multimode, then higher power output is achieved, but wavelength stability deteriorates due to temperature dependency
Solution Approach 1:
The patent uses parameter changes by establishing specific constraints on wavelength bandwidth (15 nm or less) and longitudinal mode count (3 or fewer). These parameter controls enable the system to achieve wavelength stability comparable to single-mode operation while maintaining the power advantages of multimode operation
Solution Approach 2:
The patent implements feedback through temperature control systems that monitor and adjust the semiconductor laser's operating temperature. This feedback mechanism compensates for temperature-induced wavelength shifts, maintaining stable wavelength characteristics and preventing color drift during high-power operation
3Manufacturing precision
If wavelength bandwidth is narrowed to ≤15 nm, then color reproducibility is improved, but device complexity increases due to temperature control requirements
Solution Approach 1:
The patent applies parameter changes by setting the wavelength bandwidth to 15 nm or less, which directly improves color reproducibility. This parameter constraint is achieved through controlled temperature management, balancing the trade-off between color accuracy and system 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
This approach effectively prevents color shift, ensuring high color reproducibility and stability in head-up display devices without increasing device size, by treating the semiconductor laser as if it operates in longitudinal single mode, allowing accurate representation of unique colors.
Implementation Method 1
semiconductor laser that oscillates in the longitudinal multimode and in which a width of a wavelength band with an intensity equal to or more than -20 dB relative to a peak intensity in a spectrum distribution of output light is equal to or less than 15 nm
Data Source
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AI summary
A semiconductor laser is for generating colored light. The semiconductor laser oscillates in a longitudinal multimode. A width of a wavelength band with an intensity equal to or more than -20 dB relative to a peak intensity in a spectrum distribution of output light is equal to or less than 15 nm. A light source device may include The semiconductor laser; a wavelength estimating device configured to estimate a wavelength λ of light from the semiconductor laser; and an emission-light intensity setting unit configured to set an emission light intensity of the semiconductor laser in accordance with an estimation result by the wavelength estimating device.