Projector Light Source Unit Optical Wheel Segmentation
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Solution Overview
Problem
Conventional light source units for projectors using an optical wheel with luminescent material layers in a circumferential direction face issues with light utilization efficiency due to differences in luminance between red, green, and blue wavelength bands, and inefficient use of the optical wheel's non-use areas.
Innovation Solution
A light source unit with an optical wheel featuring segment areas including multiple luminescent material layers of different characteristics, where an excitation light source and an independent light emitting source are used, allowing selective illumination of luminescent layers and utilizing a collective optical system to converge light beams from both sources, enabling effective use of the optical wheel's area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If luminescent material layers of red, green and blue are disposed uniformly on the optical wheel, then the optical wheel can generate three primary colors of light, but a difference in luminance between light beams of red, green and blue wavelength bands is increased
Solution Approach 1:
The patent applies local quality by making the luminescent material layers have different thicknesses at different positions on the optical wheel. Specifically, the red luminescent material layer has a first thickness while the green and blue luminescent material layers have a second thickness that is different from the first thickness. This local variation in thickness compensates for the inherent luminance differences between wavelength bands, allowing uniform luminance output across red, green, and blue light beams while maintaining the ability to generate all three primary colors.
2Adaptability or versatility
If an optical wheel with luminescent material layers is used to generate red, green and blue light, then color image projection is enabled, but non-use area on the optical wheel is created reducing effective use of the optical wheel
Solution Approach 1:
The patent segments the optical wheel into multiple functional zones: a first luminescent light emitting area with red, green, and blue luminescent material layers for color image projection, and a second luminescent light emitting area with only blue luminescent material layers for bright image projection. This segmentation allows different regions of the optical wheel to serve different projection modes, eliminating non-use areas and maximizing the effective utilization of the entire optical wheel surface.
Solution Approach 2:
The optical wheel is designed with multi-functionality by incorporating both color image projection capability (through the first luminescent light emitting area with multiple wavelength layers) and bright image projection capability (through the second luminescent light emitting area with blue layer only). This universal design enables a single optical wheel to support multiple projection modes, ensuring 100% utilization of the optical wheel area without creating non-use zones.
3Illumination intensity
If multiple luminescent material layers are disposed end to end in a circumferential direction, then luminance difference between wavelength bands is reduced, but the optical wheel area is not fully utilized
Solution Approach 1:
The optical wheel is segmented into two distinct luminescent light emitting areas: the first area contains red, green, and blue luminescent material layers arranged end to end in circumferential direction to achieve uniform luminance across wavelength bands, while the second area contains only blue luminescent material layers to maximize utilization. This segmentation resolves the contradiction by allowing the first area to address luminance uniformity while the second area ensures complete optical wheel utilization.
Solution Approach 2:
The patent transitions from a single-function optical wheel design to a multi-functional design by adding a second luminescent light emitting area with different characteristics (blue layer only) adjacent to the first area. This dimensional expansion of functionality allows the optical wheel to serve multiple projection purposes simultaneously, eliminating wasted area while maintaining luminance uniformity in the color projection region.
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 reduces luminance differences between wavelength bands and optimizes the use of the optical wheel's area, enhancing light utilization efficiency and enabling different projection modes with improved luminance and color purity.
Implementation Method 1
an optical wheel (71) which includes luminescent light emitting areas where two or more luminescent material layers having different characteristics are provided end to end in a circumferential direction
Implementation Method 2
a collective optical system for collecting a light beam emitted from the optical wheel and a light beam emitted from the light emitting light source for convergence to the same optical path
Implementation Method 3
a collective optical system for collecting a light beam emitted from the optical wheel and a light beam emitted from the light emitting light source for convergence to the same optical path
Data Source
AI summary
A light source unit includes an optical wheel having a plurality of segment areas, the segment areas including at least two luminescent material layers having different characteristics and a transmission portion provided in a circumferential direction. The light source unit further includes a rotation driving unit for driving to rotate the optical wheel, an excitation light source for shining light onto the optical wheel, a light emitting element, and a light guiding optical system for collecting a light beam from the optical wheel and a light beam from the light emitting element to a same optical path. The excitation light source is selectively turned on to illuminate the transmission portion or the at least two luminescent material layers, and the light emitting light source is turned on for a period of time during which the excitation light source does not shine the excitation light.