Projector Light Source Unit with Segmented Luminescent Wheel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light source units for projectors face issues with reduced luminance due to continuous driving of excitation light sources, difficulty in achieving high color balance, and lower luminous efficiency of green semiconductor light emitting devices, leading to challenges in producing bright and balanced color images.
Innovation Solution
A light source unit comprising an excitation light shining device, a luminescent plate with a luminescent material layer, and two types of light source devices (red and blue semiconductor light emitting devices) that emit light rays of different wavelength bands, controlled by a light source control device to produce synthetic or single-color light, allowing for increased luminance and improved color balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the excitation light source is driven continuously to emit light rays onto the luminescent wheel, then the light source can provide continuous illumination for the projection system, but the life of the excitation light source is shortened due to heat generated from continuous driving
Solution Approach 1:
The patent applies periodic action by driving the excitation light source in alternating cycles with the luminescent wheel rotation, rather than continuous driving. The excitation light source is activated only when needed to illuminate specific luminescent areas, creating periodic on-off cycles that reduce cumulative heat generation and extend the light source lifespan while maintaining continuous projection through sequential illumination of multiple luminescent regions.
2Reliability
If the driving output of the excitation light source is suppressed to reduce temperature increase, then the light source life is extended, but the luminance of the emitted light rays is reduced
Solution Approach 1:
The patent segments the illumination function by dividing the luminescent wheel into multiple luminescent areas with different luminescent materials, each emitting different wavelength bands. The excitation light source is selectively applied to specific luminescent areas only when those areas need to be illuminated, rather than continuously illuminating the entire wheel. This segmentation allows the system to maintain adequate luminance for each segment while reducing the cumulative burden on the excitation light source.
3Adaptability or versatility
If red, green and blue luminescent light emitting areas are formed on the luminescent wheel to emit light rays sequentially, then the system can produce colored light for projection, but it is not possible to enhance the luminance by producing white light or highly pure complementary color light through combination of the light rays
Solution Approach 1:
The patent applies local quality by creating distinct luminescent areas with specific luminescent materials positioned at different locations on the luminescent wheel. Each area has tailored optical properties to emit specific wavelength bands when excited. This spatial differentiation of luminescent characteristics allows the system to produce various color outputs including white light and highly pure complementary colors by selectively illuminating appropriate combinations of luminescent areas, thereby enhancing synthetic light luminance while maintaining color versatility.
4Ease of manufacture
If the luminous efficiency of red, green and blue light rays depends on the physical properties of the luminescent materials, then the system can produce colored light, but it is difficult to display an image with superior color balance
Solution Approach 1:
The patent applies parameter changes by utilizing luminescent materials with different emission characteristics and positioning them in specific patterns on the luminescent wheel. By varying the parameters of luminescent material selection, thickness, and spatial arrangement, the system can adjust the relative intensities of red, green, and blue light emission. This enables precise control over color balance parameters, allowing the projection system to display images with superior color balance while maintaining ease of manufacture through standardized material options.
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 enables the production of highly bright color images with improved color balance by controlling the emission of light from the excitation light shining device and the two types of light source devices, reducing the duty cycle of the excitation light source and extending its lifespan, while also enhancing the luminous efficiency and maintaining performance over time.
Implementation Method 1
a luminescent wheel in which luminescent material layers are formed on a transparent base material for converting ultraviolet light emitted from the excitation light source into visible light
Implementation Method 2
a plurality of types of semiconductor light emitting devices so that red, green and blue light rays can be produced by corresponding light emitting diodes
Data Source
AI summary
There is provided a light source unit comprising an excitation light shining device for emitting excitation light, a luminescent plate having a luminescent light emitting area on a base material and adapted to emit a luminescent light of a predetermined wavelength band by excitation light from the excitation shining device, two types of light source devices for emitting light of wavelength bands different from that of the light from the luminescent plate, a light guiding optical system for guiding the light from the luminescent plate and the rays from the light sources to a predetermined plane, and a light source control device for controlling the emission from the excitation light shining device and the light sources, wherein a synthetic light or a single-color light are emitted by controlling the emissions from the excitation light shining device and the light sources by the light source control device.