Illumination System with Phosphor Wheel Beam Guidance
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Solution Overview
Problem
Conventional projector designs face issues with large volume, high cost, and reduced image brightness due to unnecessary optical guide elements and the speckle phenomenon caused by laser beam reflection and heat generation during prolonged use.
Innovation Solution
The illumination system features a reflection cover with a focal point aligned with the excitation beam's transmission path, eliminating the need for additional optical guide elements and incorporating a wavelength conversion element with a light-action region adjacent to the focal point, which reduces heat buildup and scattering, thereby enhancing image quality and projector reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If optical guide elements and additional optical paths are configured in the phosphor wheel to redirect the laser beam, then the laser beam can be guided away from the original path, but the volume of the projector increases and the cost increases
Solution Approach 1:
The patent combines the beam guidance function into the existing phosphor wheel structure by creating a transparent region with integrated optical guide elements, rather than adding separate optical paths. This merging approach allows the phosphor wheel to serve dual purposes: wavelength conversion and beam guidance, thereby reducing overall projector volume and component count.
Solution Approach 2:
The phosphor wheel is designed to perform multiple functions simultaneously: it converts laser wavelength to visible light through phosphor excitation, and also guides the laser beam through its transparent region with integrated optical elements. This multi-functionality eliminates the need for dedicated beam guidance components, reducing projector volume and cost.
2Productivity
If the laser beam continuously irradiates the phosphor on the phosphor wheel, then the phosphor wheel can continuously generate conversion beams, but a large amount of heat is generated causing the intensity of the conversion beam to decrease and image brightness to reduce
Solution Approach 1:
The phosphor wheel is segmented into multiple regions including phosphor regions and transparent regions with optical guide elements. This segmentation allows portions of the laser beam to pass through the transparent regions without interacting with phosphor material, reducing overall heat generation while maintaining continuous conversion beam generation capability through the phosphor regions.
Solution Approach 2:
Different regions of the phosphor wheel have different optical properties: phosphor regions for wavelength conversion and transparent regions for beam guidance with reduced interaction. This local quality differentiation optimizes the balance between continuous beam generation and heat management, maintaining conversion beam intensity during prolonged operation.
3Ease of manufacture
If a conventional dichroic mirror is used to transmit the laser beam and reflect conversion beams, then the wavelength corresponding to the laser beam can penetrate through, but the laser beam may directly penetrate through and transmit back to the original laser source causing the speckle phenomenon
Solution Approach 1:
The patent extracts the problematic direct reflection path by introducing a transparent region with optical guide elements that redirects the laser beam away from returning to the laser source. This extraction of the harmful reflection path eliminates the speckle phenomenon while maintaining the simple dichroic mirror configuration for wavelength separation.
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 design results in a compact, cost-effective projector with improved image quality and reliability by minimizing optical complexity and heat-related efficiency losses, while reducing the speckle phenomenon.
Implementation Method 1
the focal point of the reflection cover is disposed on an extension line of a transmission path of the excitation beam, so that the excitation beam emitted by the light source is reflected to the focal point of the reflection cover
Implementation Method 2
the wavelength conversion element penetrates through the opening, and has a light-action region. The light-action region of the wavelength conversion element is disposed on the transmission path of the excitation beam, so that when the excitation beam is converted into the conversion beam by the light-action region
Data Source
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AI summary
An illumination system including at least one light source which can be a laser, a reflection cover which can be a parabolic mirror, a wavelength conversion element which can be a phosphor, and a filter element which can be a color weel is provided. A focal point of the reflection cover is disposed on an extension line of a transmission path of an excitation beam provided by the light source, and an opening of the reflection cover is adjacent to the focal point and can be at the apex of the parabolic mirror. The wavelength conversion element penetrates through the opening, and has a light-action region. The light-action region is disposed on the transmission path of the excitation beam, and converts the excitation beam into a conversion beam. The reflection cover is disposed on a transmission path of the conversion beam. The filter element is disposed on a transmission path of the conversion beam from the reflection cover. The conversion beam from the reflection cover is obliquely incident to the filter element, and the filter element filters the conversion beam.