Single-Segment Phosphor Illumination System for Projectors
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Solution Overview
Problem
Conventional illumination systems for projectors face issues with high cost, weight, and performance degradation at high temperatures due to the use of red phosphor agents, leading to increased fabricating time and difficulty, as well as low luminance and illuminance decay when the driving current of the blue light laser rises.
Innovation Solution
The system employs a single solid-state light-emitting element and a single segment wavelength-transforming device, eliminating the need for red phosphor agents by transforming a first color light into a second color light in a wider waveband region, thereby simplifying fabrication, reducing costs, and improving color purity and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If red phosphor agent is used in the phosphor wheel, then red light can be generated, but the cost increases, weight increases, and performance degrades at high temperatures
Solution Approach 1:
The patent removes the red phosphor agent from the phosphor wheel structure entirely. Instead of using a multi-segment phosphor wheel with red phosphor coating, the invention uses a single-segment phosphor wheel that only contains green phosphor, thereby eliminating the problematic red phosphor material and its associated cost, weight, and temperature performance issues.
Solution Approach 2:
The patent introduces a dichroic mirror as an intermediary optical element to separate the green light (generated by phosphor conversion) from the blue light (directly emitted by the LED). This allows the system to achieve full-color projection without needing red phosphor, as the dichroic mirror enables selective light path routing based on wavelength.
2Illumination intensity
If red phosphor agent is coated on phosphor wheel, then red light is emitted, but the fabrication time and difficulty increase
Solution Approach 1:
By extracting and removing the red phosphor agent coating process from the manufacturing workflow, the patent significantly reduces fabrication time. The single-segment phosphor wheel design eliminates the need for multi-step coating processes required for multi-segment wheels, streamlining production.
Solution Approach 2:
The patent merges the functions of multiple phosphor segments into a single phosphor segment. Instead of separately coating different phosphor materials on different wheel segments, the invention uses one unified green phosphor coating, simplifying the fabrication process and reducing manufacturing complexity.
3Illumination intensity
If red phosphor agent is used, then red light is produced, but the weight of phosphor wheel increases requiring rotation balance fixation
Solution Approach 1:
The patent extracts and removes the heavy red phosphor agent material from the phosphor wheel. By using only green phosphor in a single-segment design, the overall weight of the rotating phosphor wheel is significantly reduced, eliminating the need for complex rotation balance fixation mechanisms.
4Illumination intensity
If driving current of blue light laser increases, then luminance increases, but luminance and illuminance decay due to red phosphor agent characteristics
Solution Approach 1:
By removing the red phosphor agent from the system, the patent eliminates the fundamental cause of luminance and illuminance decay that occurs at high driving currents. The green phosphor-based single-segment wheel does not exhibit the same degradation characteristics as red phosphor under high-current conditions.
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 approach avoids luminance and illuminance decay, reduces fabricating costs, and enhances image quality by using a single solid-state light-emitting element and a single segment wavelength-transforming device, allowing for effective emission of red light without red phosphor agents, even at high working temperatures.
Implementation Method 1
a blue solid-state light-emitting element 11 of a conventional illumination system 1 emits blue light B to a phosphor wheel 12 including a first segment 121, a second segment 122 and a third segment 123. The first segment 121 is coated with a green phosphor agent in order to excite the incident blue light B as exit green light. The second segment 122 is coated with a red phosphor agent in order to excite the incident blue light B as exit red light.
Implementation Method 2
The filter wheel 33 is disposed on one side of the wavelength-transforming device 31 for filtering lights through rotating
Data Source
AI summary
An illumination system includes a wavelength-transforming device, a solid-state light-emitting element and a filter wheel. The wavelength-transforming device comprises a segment and a wavelength-transforming element disposed on the segment. The solid-state light-emitting element emits first color light in first waveband region to the wavelength-transforming device. The filter wheel is disposed on one side of the wavelength-transforming device for filtering lights via rotating. The first color light is excited as second color light in second waveband region by the wavelength-transforming device, so that the second color light is outputted with the rest of the first color light. The first and second color lights are transmitted through the filter wheel, such that three primary color lights are sequentially projected. The present invention achieves the advantages of reducing cost, simplifying fabricating processes, being available for high working temperature, and further improving image quality without using red phosphor agent or red solid-state light-emitting element.