Filter Wheel Blocking Region for Projection Color Uniformity
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Solution Overview
Problem
Projection apparatuses face color differences due to the inability to set the light valve to an OFF state during certain intervals, affecting chromaticity coordinates and contrast of the image beam.
Innovation Solution
An illumination system is designed with a wavelength conversion wheel and a filter wheel, including a blocking region that blocks undesired beams from passing through during specific intervals, preventing color differences by ensuring the light valve remains in an OFF state when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the light valve is set to OFF state during interval to avoid color difference, then chromaticity coordinates and contrast are improved, but the system complexity and control difficulty increase
Solution Approach 1:
The patent extracts the problematic excitation beam from the optical path by introducing a blocking region in the filter wheel. This blocking region selectively blocks the excitation beam during specific time intervals when the wavelength conversion region is not in the optical path, preventing it from reaching the light valve and causing color differences. This solution avoids the need for complex light valve control while maintaining image quality.
Solution Approach 2:
The blocking region acts as an intermediary element between the excitation beam and the light valve. Instead of directly controlling the light valve state, the blocking region mediates by selectively preventing the excitation beam from reaching the light valve during critical intervals, thereby avoiding color differences through a simpler mechanical blocking mechanism.
2Manufacturing precision
If the blocking region angle is made smaller than the first optical region angle, then color difference is avoided, but the device complexity increases
Solution Approach 1:
The filter wheel is designed with different regional characteristics: the blocking region has a smaller angle than the first optical region angle. This local differentiation in angular size allows the blocking region to precisely block the excitation beam only during the necessary intervals when the wavelength conversion region is out of path, while maintaining proper color transition during other intervals. The non-uniform angular distribution optimizes both color uniformity and operational timing.
3Ease of operation
If the light valve cannot be set to OFF state, then the system operation is simpler, but color difference occurs affecting image quality
Solution Approach 1:
The patent converts the potentially harmful excitation beam into a beneficial blocking mechanism. By introducing the blocking region that selectively blocks the excitation beam during specific intervals, the system transforms what would be a harmful color-causing element into a controlled feature that prevents color differences. The blocking region's strategic placement and angular design allow it to eliminate the harmful effect of the excitation beam leaking into the optical path at wrong times.
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 effectively prevents the output of undesired colored beams, thereby avoiding color differences in the image beam, ensuring improved chromaticity and contrast.
Implementation Method 1
The wavelength conversion region and the first optical region alternately enter a transmission path of the first excitation beam. The first excitation beam is converted into a conversion beam by the wavelength conversion region when the wavelength conversion region enters the transmission path of the first excitation beam.
Implementation Method 2
The blocking region is configured to block the first excitation beam or the conversion beam transmitted from the wavelength conversion wheel from passing through the filter wheel.
Data Source
AI summary
An illumination system including a first excitation light source, a wavelength conversion wheel, and a filter wheel is provided. The first excitation light source is configured to emit a first excitation beam. The wavelength conversion wheel includes a wavelength conversion region and a first optical region. The wavelength conversion region and the first optical region alternately enter a transmission path of the first excitation beam. The first excitation beam is converted into a conversion beam by the wavelength conversion region when the wavelength conversion region enters the transmission path of the first excitation beam. The filter wheel includes a first region, a second region, and a blocking region. An angle covered by the second region in a circumferential direction is smaller than an angle covered by the first optical region. A projection apparatus is also provided.