Compact Light Source Unit with Aligned Optical Axes
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Solution Overview
Problem
Existing light source units for projectors face challenges in achieving a small size while maintaining superior color reproduction performance, particularly due to the complexity of aligning the optical paths of red, green, and blue light sources and the inferior luminance and color purity of luminescent materials used in rotary wheels.
Innovation Solution
A light source unit comprising a blue light source device as the first light source, a luminescent material wheel as the second light source, and a red light source device, where the optical axes of blue, green, and red light are aligned using a polarizing dichroic mirror and quarter-wave plate to simplify the optical path and utilize high-efficiency red light emitting diodes for improved color reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If luminescent materials are used in rotary wheels for green light emission, then the projector can achieve color reproduction, but the luminance and color purity are inferior
Solution Approach 1:
The patent combines blue LED light sources with green and red phosphor materials on the same rotary wheel, merging multiple light generation mechanisms into a single integrated system. This allows the blue LED to excite both green phosphor and directly contribute to blue light output, improving overall luminance and color purity simultaneously
Solution Approach 2:
The patent uses composite phosphor materials with specific particle sizes and compositions on the rotary wheel. The green phosphor is combined with red phosphor in specific ratios and configurations, creating a composite material system that enhances both luminance and color purity by optimizing the spectral characteristics of each phosphor component
2Reliability
If multiple separate light source devices are used for red, green, and blue light, then superior color reproduction can be achieved, but the device size and optical path alignment complexity increase
Solution Approach 1:
The patent merges the functions of multiple separate light source devices into a single rotary wheel assembly. The blue LED and phosphor materials are integrated on the same rotating component, eliminating the need for separate alignment of multiple light source devices and their associated optical paths, thereby reducing device complexity while maintaining color reproduction quality
Solution Approach 2:
The rotary wheel serves multiple functions simultaneously: it acts as the blue light source, the green light source through phosphor conversion, and the red light source through phosphor emission. This multi-functionality eliminates the need for separate dedicated light source devices for each primary color, simplifying the overall device structure and optical path alignment
3Reliability
If the optical paths of red, green, and blue light sources are aligned separately, then color reproduction performance improves, but the projector size increases
Solution Approach 1:
The patent combines the optical paths of red, green, and blue light into a single integrated optical path by using the rotary wheel as a common light source for all three colors. The blue LED light and phosphor-generated light (green and red) are collected and directed through a unified optical system, reducing the overall projector size while maintaining color reproduction performance
Solution Approach 2:
The patent uses the rotational dimension of the rotary wheel to sequentially present different color light sources to a stationary collection optical system. By rotating the wheel, blue LED light and phosphor-excited light are brought into the optical path at different angular positions, allowing compact 3D packaging of what would otherwise require separate linear optical paths
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 configuration allows for a compact projector design with enhanced color reproduction capabilities and improved luminance, overcoming the limitations of previous technologies by aligning the optical axes of blue, green, and red light sources and utilizing high-efficiency LEDs for the red light source.
Implementation Method 1
a luminescent light emitting area 102 which receives light in a first wavelength range to thereby emit light in a second wavelength range
Implementation Method 2
a polarizing dichroic mirror transmits light in a first wavelength range and reflects light in a second wavelength range
Implementation Method 3
a quarter-wave plate which converts linearly polarized light to circularly polarized light
Data Source
AI summary
To provide a light source unit whose overall size is relatively small and a projector which incorporates the light source unit, there is provided a light source unit including a first light source device for emitting light in a first wavelength range, a second light source device which is disposed on an axis of the light in the first wavelength range and having a luminescent light emitting area for emitting light in a second wavelength range by receiving the light in the first wavelength range, and a third light source device which is disposed on the axis of the light in the first wavelength range so as to face the first light source device for emitting light in a third wavelength range.