Light Source Unit Feedback Control for Wavelength Stability
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Solution Overview
Problem
Semiconductor lasers used in projectors face challenges with emission wavelength and light emitting intensity variations due to temperature changes and aging, leading to color and brightness instability, which is difficult to automatically adjust and stabilize, especially in high-fidelity applications.
Innovation Solution
A light source unit with multiple elemental light sources emitting different wavelength bands, driven by integrated control circuits that acquire and adjust light emitting intensity values through feedback control, using band optical characteristic acquisition data to match target color phases and brightness, even with wavelength deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If semiconductor lasers are used as light sources, then high brightness and color purity are achieved, but emission wavelength and light emitting intensity vary due to temperature changes and aging
Solution Approach 1:
The patent implements feedback control by measuring the emission wavelength of each semiconductor laser and adjusting its drive current accordingly. The control unit receives wavelength information from detection means and modifies the drive current to maintain the emission wavelength within a predetermined range, thereby compensating for temperature changes and aging effects.
Solution Approach 2:
The patent changes the drive current parameter of the semiconductor lasers based on measured wavelength deviations. By dynamically adjusting the drive current, the system compensates for wavelength shifts caused by temperature variations and aging, maintaining stable emission characteristics.
2Adaptability or versatility
If multiple semiconductor lasers with different wavelength bands are used, then color display capability is improved, but automatic adjustment of light emitting intensity for each wavelength band becomes complex
Solution Approach 1:
The patent implements feedback control by measuring the emission wavelength of each semiconductor laser and adjusting its drive current accordingly. The control unit receives wavelength information from detection means and modifies the drive current to maintain the emission wavelength within a predetermined range, thereby compensating for temperature changes and aging effects.
Solution Approach 2:
The patent employs a single integrated control unit that handles multiple functions: detecting emission wavelengths, determining drive currents, and controlling multiple semiconductor lasers with different wavelength bands. This universal control approach simplifies the system architecture while maintaining the ability to independently adjust each laser's parameters.
3Reliability
If feedback control is implemented to stabilize color and brightness, then image quality consistency is improved, but system complexity and control circuit requirements increase
Solution Approach 1:
The patent merges the detection function and control function into a single integrated control unit. The control unit both detects the emission wavelengths and determines the appropriate drive currents, eliminating the need for separate detection and control circuits. This integration reduces overall system complexity while maintaining effective feedback control.
Solution Approach 2:
The control unit automatically adjusts the drive currents of the semiconductor lasers based on measured wavelength deviations, without requiring external manual intervention. The system self-regulates to maintain stable emission characteristics, reducing the need for complex external control mechanisms.
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 stabilizes color and brightness by adjusting light emitting intensity values across different wavelength bands, ensuring consistent image quality despite temperature changes and aging effects.
Implementation Method 1
light emitting elements that emit light of an emission wavelength including a plurality of different wavelength bands
Data Source
AI summary
A light source unit includes: elemental light sources each including light emitting elements and drive circuits; an integrated control circuit that controls the drive circuits; and band optical characteristic acquisition sections that receive light of an amount correlated with a total light amount of output luminous fluxes to acquire light emitting intensity indicating values and wavelength deviation indicating values. The integrated control circuit at least intermittently acquires band optical characteristic acquisition data to generate the light emitting intensity indicating values and the wavelength deviation indicating values. The integrated control circuit holds light emitting intensity indicating value target variation information, and determines the variation of the light emitting intensity indicating values, in accordance with the light emitting intensity indicating value target variation information belonging to one appearance mode of the wavelength deviation indicating values assumed on a basis of an actual mode of the generated wavelength deviation indicating values.