Projection Display Optical Path Separator for Green Light Spectral Segmentation
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Solution Overview
Problem
The spectral distribution of green light sources with wide spectral distributions, when combined with blue and red light in projection display apparatuses, leads to inefficient light utilization due to overlapping wavelength bands, resulting in reduced intensity of blue and red light.
Innovation Solution
A projection display apparatus that includes a first light source emitting a first wavelength band, an optical path separator separating the light into orthogonal polarized third and second light, and an optical path combiner that reflects specific wavelengths to improve the combination of green light with blue and red light, maintaining intensity without degrading blue or red light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a phosphor LED with wide spectral distribution is used to increase green light brightness, then the green light intensity is improved, but the light utilization efficiency deteriorates due to spectral overlap with blue and red light
Solution Approach 1:
The patent segments the green light spectrum into two distinct bands using a first wavelength band (500-560nm) and second wavelength band (560-600nm). This segmentation allows the green light to be separated from the blue and red light spectral regions, preventing overlap and enabling efficient combination of all three primary colors without energy loss from spectral interference.
Solution Approach 2:
The patent applies local quality by assigning different spectral characteristics to different light sources: the first light source emits green light with a specific spectral distribution (500-560nm), while the second light source emits green light with a different spectral distribution (560-600nm). This local differentiation of spectral properties allows each light source to occupy a distinct spectral niche, avoiding overlap and maximizing light utilization efficiency.
2Illumination intensity
If multiple green LEDs are combined to increase green light intensity, then the green light brightness is improved, but the device complexity increases due to multiple light sources and polarization separation components
Solution Approach 1:
The patent merges the functions of multiple green light sources by combining their outputs through polarization separation and combination optics. The first and second green light sources are separated by polarization direction, then recombined with blue and red light sources in a single optical path, eliminating the need for separate optical paths for each light source and reducing overall device complexity.
Solution Approach 2:
The patent creates multi-functionality by using a single optical combining system that handles multiple light sources with different wavelengths and polarization states. The optical path separator and combiner serve multiple functions: separating green light from blue and red light, combining all primary colors, and managing polarization directions, thereby reducing the need for multiple dedicated optical components.
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 solution enhances the light utilization efficiency by combining green light with blue and red light effectively, improving the intensity of green light without reducing the intensity of blue or red light, even when using a light source with a wide spectral distribution.
Implementation Method 1
an optical path separator that separates the first light into third light and second light whose polarization directions are orthogonal to each other
Implementation Method 2
an optical path separator and combiner that separates the second light into fourth light and fifth light having different wavelength bands from each other
Implementation Method 3
a reflector that reflects the fifth light to a direction of the optical path separator and combiner
Implementation Method 4
an optical path combiner that combines the third light and the second light
Data Source
AI summary
A first light source that emits first light of a first wavelength band; an optical path separator that separates the first light into third light and second light whose polarization directions are orthogonal to each other; an optical path separator and combiner that separates the second light into fourth light and fifth light having different wavelength bands from each other; a reflector that reflects the fifth light to a direction of the optical path separator and combiner; and an optical path combiner that combines the third light and the second light are included.