Light Source Unit Segmentation for Projector Luminance
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Solution Overview
Problem
Conventional light source units for projectors, particularly those using high-intensity discharge lamps, face challenges in achieving sufficient luminance due to the lower luminous efficiency of red luminescent materials, leading to inadequate screen illumination.
Innovation Solution
A light source unit comprising a primary light source that emits ultraviolet radiation, a luminescent wheel with segment areas coated with blue and green luminescent materials, and a secondary light source emitting red light, where the light source control means synchronizes the primary and secondary light sources to ensure optimal illumination by adjusting their activation times to overlap or exclude each other at segment boundaries, thereby enhancing luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If luminescent material layers are disposed with substantially the same ratios in the circumferential direction of the luminescent wheel, then the structure is simple and uniform, but the luminance of red becomes insufficient due to lower luminous efficiency of red luminescent material
Solution Approach 1:
The patent applies local quality by making the thickness of the red luminescent material layer greater than that of other luminescent material layers at specific locations where red light is needed. This compensates for the lower luminous efficiency of red luminescent material and achieves sufficient red luminance without requiring complex overall structural changes to the luminescent wheel.
2Illumination intensity
If a single light source is used to excite all luminescent materials, then the device is simple, but the luminance efficiency is insufficient for red light
Solution Approach 1:
The patent segments the light source function by using a first light source for exciting blue and green luminescent materials and a second light source for exciting the red luminescent material. This segmentation allows each light source to be optimized for specific wavelength ranges, improving overall luminance efficiency while maintaining reasonable device complexity through functional division.
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 significantly increases the luminance of the projected image by effectively combining the high-efficiency blue and green luminescent light with red light, improving the overall brightness and color accuracy of the screen.
Implementation Method 1
the luminescent material layers become luminous so as to emit luminescent light rays of red, green and blue wavelength bands
Implementation Method 2
luminescent material layers which receive ultraviolet rays emitted from the solid-state light source as excitation light to convert them into visible light
Data Source
AI summary
To provide a light source unit which can enhance luminance and a projector, a projector of the invention includes a light source unit comprising a luminescent wheel with luminescent light emitting portions to emit blue and green rays, a primary light source shining an excitation light to the luminescent light emitting portions, a secondary light source emitting a red ray, a light guiding optical system guiding the rays from the luminescent wheel and the ray from the secondary light source to the same optical path and a light source control means controlling the emissions from the respective light sources, wherein the light source control means turns on the secondary light source when the ray from the primary light source is shone onto a boundary between the luminescent light emitting portions to synthesize the rays from the luminescent wheel and the ray from the secondary light source to generate white ray.