Laser Projector Wave-Plate Layout for Color Speckle Control
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Solution Overview
Problem
Laser projection systems suffer from local color aberration phenomena such as 'color speckle' and 'color patch' due to differences in polarization directions of red, blue, and green laser light, leading to poor image quality.
Innovation Solution
A laser projector design that includes a laser assembly with red, blue, and green laser light emitting regions, where the polarization directions are adjusted using phase delaying components like half-wave plates to align with the polarization direction of red laser light, ensuring all laser light is either P-polarized or S-polarized, and combined using beam combination mirrors, followed by beam shaping and homogenization to reduce chromaticity differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If three-color laser light sources with different polarization directions are used for projection imaging, then high brightness and long service life are achieved, but local color aberration phenomena such as color speckle and color patch occur
Solution Approach 1:
The patent changes the polarization state parameter of the laser light by introducing wave plates (half-wave plates or quarter-wave plates) in the optical path. These wave plates convert the linearly polarized light from different laser sources into circularly polarized light or uniformly polarized light, thereby eliminating the color speckle and color patch effects caused by polarization direction differences while maintaining high brightness
Solution Approach 2:
The patent introduces wave plates as intermediary optical components between the laser light sources and the projection system. These wave plates act as mediators that transform the polarization states of red, green, and blue laser lights to be consistent, thereby eliminating the harmful color aberration effects without affecting the high brightness characteristic
2Adaptability or versatility
If hybrid laser light sources combining monochromatic laser light and fluorescent light are used, then red, green, and blue laser light can be generated, but color speckle and color patch phenomena occur due to different polarization directions
Solution Approach 1:
The patent applies wave plates to change the polarization parameter of laser light from different color sources. By converting linearly polarized light into circularly polarized light or uniformly polarized light, the system maintains its ability to generate red, green, and blue colors while eliminating the color speckle and color patch phenomena caused by polarization direction differences
Solution Approach 2:
The patent makes the polarization states of red, green, and blue laser lights homogeneous by using wave plates to transform them into the same polarization state (circular or uniform linear polarization). This homogenization of polarization parameters eliminates the color aberration effects while preserving the color generation capability of the hybrid laser light source
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 effectively eliminates local color aberration, improving the consistency and brightness of the projected image by ensuring uniform processing of red, blue, and green laser light across the projection system, thereby enhancing image quality.
Implementation Method 1
red laser light is polarized in a first direction, the green laser light is polarized in a second direction, the blue laser light is polarized in a third direction
Implementation Method 2
a phase delaying component, on a light emitting path of at least one of the red laser light, the blue laser light or the green laser light, and configured to change a polarization direction of the at least one of the red laser light, the blue laser light or the green laser light
Data Source
AI summary
A laser projector includes a laser assembly, a beam combination mirror group and a phase delaying component. The laser assembly includes a red laser light emitting region, a blue laser light emitting region and a green laser light emitting region. Red laser light is polarized in a first direction, green laser light is polarized in a second direction, and blue laser light is polarized in a third direction. The beam combination mirror group combines the red laser light, the blue laser light and the green laser light. The phase delaying component is on a light emitting path of at least one of the red laser light, the blue laser light the green laser light, and changes a polarization direction of the at least one of the red laser light, the blue laser light or the green laser light before being output by the beam combination mirror group.