Light Source Optical System Illuminance Distribution
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Solution Overview
Problem
Projectors using ultra-high pressure mercury lamps face short lamp life and frequent maintenance, while those using lasers or LEDs have longer life but uneven illuminance distribution, particularly with red and green lasers having lower luminous efficacy than blue lasers.
Innovation Solution
A light source optical system that includes a first optical system guiding a blue laser beam to a phosphor wheel for wavelength conversion, producing green and red light, and a second optical system using a light guide element to improve illuminance distribution by reflecting and transmitting polarized light, thereby enhancing the uniformity of the projected image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If ultra-high pressure mercury lamps are used as light sources, then high brightness is achieved, but lamp life is short and frequent maintenance is required
Solution Approach 1:
The patent transitions from mercury lamp light sources to laser light sources, fundamentally changing the operating parameters and mechanism of light generation. This parameter change enables significantly extended lamp life while maintaining or improving brightness through the use of solid-state laser technology with much longer operational durability.
Solution Approach 2:
The patent replaces the thermal-mechanical mercury lamp system with a solid-state laser system. This substitution eliminates the mechanical wear and thermal degradation issues inherent in mercury lamps, resulting in dramatically extended service life and reduced maintenance requirements while preserving high illumination output.
2Duration of action of stationary object
If red and green lasers are used to achieve long life, then luminous efficacy is lower compared to blue lasers
Solution Approach 1:
The patent introduces a wavelength conversion element (phosphor wheel) as an intermediary between the blue laser source and the final multi-color output. The blue laser excites the phosphor material to generate green and red wavelengths, thereby achieving long light source life with improved overall luminous efficacy compared to using direct red and green lasers.
Solution Approach 2:
The patent changes the approach from directly using low-efficacy red and green lasers to using a high-efficacy blue laser with wavelength conversion. This parameter change in the light generation method preserves the long operational life of laser sources while significantly improving energy efficiency through the phosphor conversion process.
3Duration of action of stationary object
If lasers or LEDs are used as light sources, then longer life is achieved, but uneven illuminance distribution occurs on the projection surface
Solution Approach 1:
The patent segments the laser beam into multiple wavelength components using a rotating phosphor wheel with different phosphor materials. This segmentation of the optical path and wavelength conversion process, combined with the rotating mechanism, helps distribute the light more uniformly across the projection surface while maintaining the long life benefits of laser sources.
Solution Approach 2:
The patent introduces dynamic motion through the rotating phosphor wheel to achieve uniform illuminance distribution. The rotation continuously varies the interaction between the laser beam and phosphor materials, creating a time-averaged uniform light output that resolves the static unevenness problem inherent in direct laser projection while preserving laser longevity.
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 achieves improved illuminance distribution and longer projector life with reduced maintenance, maintaining high color reproducibility and luminous efficacy across the image projection surface.
Implementation Method 1
a wavelength conversion element configured to convert the first light beam into a second light beam having a second wavelength different from the first wavelength
Implementation Method 2
a light guide element configured to guide a portion of the second light beam from one end surface of the light guide element to the other end surface of the light guide element
Data Source
AI summary
A light source optical system includes: a first optical system configured to guide a first light beam having a first wavelength emitted from a light source to a wavelength conversion element; the wavelength conversion element configured to convert the first light beam into a second light beam having a second wavelength different from the first wavelength, and emit the second light beam; and a second optical system through which the second light beam emitted from the light conversion element passes. The second optical system includes a light guide element configured to guide a portion of the second light beam from one end surface of the light guide element to the other end surface of the light guide element to separate the portion of the second light beam from the second light beam.