Laser Light Source Unit with Secondary LED for Projector Red Luminance
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Solution Overview
Problem
Conventional light source units for projectors, particularly those using luminescent wheels, suffer from insufficient red luminance due to low light emitting efficiency of red luminescent materials, leading to reduced screen brightness and color accuracy.
Innovation Solution
A light source unit incorporating a luminescent wheel with segment areas coated with luminescent materials of high efficiency, a primary light source for excitation, a secondary light source emitting a different wavelength band, and a light guiding system to combine these lights, along with a control mechanism to time-share color emission, ensuring optimal color reproduction and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a luminescent wheel with red luminescent material is used to generate red light, then the projector can display red color, but the light emitting efficiency of red luminescent material is remarkably lower than other luminescent materials, causing insufficient red luminance
Solution Approach 1:
The patent combines a luminescent wheel with red luminescent material and a red light emitting diode light source. The red light from the LED is merged with the red luminescent light to compensate for the low efficiency of red luminescent materials, thereby improving red luminance without excessive energy loss.
Solution Approach 2:
The patent uses a composite light source system that includes both luminescent materials and LED light sources. This composite approach allows the system to leverage the advantages of both technologies: the color quality of luminescent materials and the efficiency of LED light sources, particularly for the red wavelength band.
2Illumination intensity
If only luminescent materials are used in the luminescent wheel, then the structure can be simple, but the luminance of red becomes insufficient due to low light emitting efficiency
Solution Approach 1:
The patent merges the luminescent wheel structure with an additional red LED light source. This combination increases screen luminance by providing an alternative red light path, while the integration is designed to minimize structural complexity through shared optical components and compact arrangement.
3Adaptability or versatility
If ultraviolet light is shone on the luminescent material layer to generate visible light, then red, green and blue wavelength bands can be emitted, but the red luminescent material has remarkably lower light emitting efficiency than other luminescent materials
Solution Approach 1:
The patent combines ultraviolet excitation of the luminescent wheel with direct red LED emission. This dual-path approach ensures comprehensive color wavelength coverage through UV excitation while compensating for red efficiency losses through the dedicated red LED source.
Solution Approach 2:
The patent changes the light generation parameter for the red wavelength band by introducing a red LED light source with different emission characteristics. This parameter change (from luminescent conversion to direct LED emission) improves red light efficiency while maintaining the overall color spectrum coverage.
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 enhances luminance and color tone in projected images by effectively combining light from primary and secondary sources, addressing the inefficiencies in existing technologies and providing a brighter, more accurate color representation.
Implementation Method 1
a luminescent material layer which emits light having a predetermined wavelength band by receiving excitation light
Implementation Method 2
a luminescent material layer which emits light having a predetermined wavelength band by receiving excitation light
Implementation Method 3
a light guiding optical system for guiding light emitted from the light emitting plate and light emitted from the secondary light source to the same optical path
Data Source
AI summary
A light source unit includes a light emitting plate which has a plurality of segment areas and in which a luminescent material layer which emits light having a predetermined wavelength band by receiving excitation light and a transmissive portion which transmits light are formed on at least the plurality of segment areas, a primary light source for emitting excitation light on to the luminescent material, a secondary light source for emitting light having a wavelength band which differs from those of luminescent light emitted from the luminescent material layer and excitation light emitted from the primary light source, a light guiding optical system for guiding light emitted from the light emitting plate and light emitted from the secondary light source to the same optical path, and a light source control means for controlling the emission of light from the primary light source and the secondary light source.