Light Source Device Using Polarization Split Element for Projectors
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Solution Overview
Problem
Existing light source devices for projectors face issues with light loss in either the red laser beam or fluorescence due to the properties of combining mirrors, and they often require multiple diffusion plates, increasing costs.
Innovation Solution
A light source device incorporating a blue laser emitting element, a red laser emitting element, a phosphor for fluorescence generation, a polarization split element, and a diffusion element with a dichroic layer, which splits and diffuses light to minimize losses and reduce costs by using a single diffusion element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the transmittance of the combining mirror for the red component is increased, then the red laser beam transmission is improved, but light loss in the red laser beam increases
Solution Approach 1:
The patent divides the red light path into two separate channels: one for the red laser beam and another for the red component of fluorescence. By using a beam splitter and separate optical paths, the system can optimize transmission for each channel independently, avoiding the trade-off between laser beam transmission and fluorescence utilization.
Solution Approach 2:
The patent introduces a beam splitter as an intermediary element that separates the red laser beam from the fluorescence path. This allows the red laser beam to be transmitted with high efficiency while the fluorescence can be reflected and directed to the projection path without interfering with each other.
2Illumination intensity
If the reflectance of the combining mirror for the red laser beam is increased, then the red laser beam reflection is improved, but light loss in the fluorescence increases
Solution Approach 1:
The patent segments the optical paths using a beam splitter, allowing the red laser beam to be reflected with high efficiency while the fluorescence passes through or is separately directed. This segmentation eliminates the need for high reflectance at the cost of fluorescence loss.
Solution Approach 2:
The beam splitter acts as an intermediary that enables high reflectance for the red laser beam while maintaining high transmittance for the fluorescence. This intermediary element resolves the contradiction by providing wavelength-selective or polarization-selective separation of the two light paths.
3Illumination intensity
If multiple diffusion plates are used, then light diffusion is improved, but cost increases
Solution Approach 1:
The patent combines multiple diffusion functions into a single diffusion plate by integrating different diffusion patterns or properties into one element. This merging approach maintains effective light diffusion while reducing the total number of components and lowering costs.
Solution Approach 2:
The single diffusion plate is designed to perform multiple diffusion functions simultaneously, serving as a universal element that replaces what would traditionally require multiple separate diffusion plates. This multi-functional design reduces system complexity and cost.
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 minimizes light loss, enhances the use efficiency of the red component of fluorescence, and maintains optimal white balance while reducing the number of diffusion elements needed, thereby lowering costs and preventing color unevenness in the display.
Implementation Method 1
a polarization split element having a polarization split function with respect to the blue light and the red light having the predetermined wavelength band
Implementation Method 2
a phosphor excited by excitation light to emit fluorescence
Implementation Method 3
a diffusion element including a diffusion layer configured to diffuse incident light
Implementation Method 4
a dichroic layer configured to reflect the blue light and transmit the red light
Data Source
AI summary
A light source device is provided with a blue laser emitting element, a red laser emitting element, a phosphor, a polarization split element having a polarization split function with respect to blue light and red light, and a diffusion element. The blue light emitted from the blue laser emitting element enters the polarization split element to be split into a first blue polarization component and a second blue polarization component. The first blue polarization component enters the diffusion element to turn to blue diffused light. The phosphor is excited by the second blue polarization component to emit fluorescence, and the red light emitted from the red laser emitting element enters the diffusion element to be diffusely transmitted to turn to red diffused light. The blue diffused light, the red diffused light and a part of the fluorescence are combined with each other, and then emitted from the polarization split element.