Laser Projection Source Using Polarization Beam Combining
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Solution Overview
Problem
Existing laser projection technologies face challenges in achieving high luminance, long service life, and low power consumption while addressing issues such as speckle effects and inefficient beam combination, which affect the projection quality and user experience.
Innovation Solution
A laser source comprising multiple laser devices, beam expanding components, combining lens groups, and polarization conversion components to emit and combine laser beams of different colors, with a digital micromirror device for modulation, and a projection lens for image projection, enhancing beam homogeneity and reducing speckle effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple laser devices emit laser beams of different colors, then the luminance and service life are improved, but the beam combination efficiency deteriorates due to overlapping beam paths
Solution Approach 1:
The patent introduces polarization as an additional dimension for beam separation. By assigning different polarization directions to different color laser beams (e.g., horizontal polarization for red, vertical polarization for green and blue), the system achieves beam separation in the polarization domain, allowing all beams to share the same spatial path without overlapping, thus improving combination efficiency while maintaining high luminance
2Duration of action of stationary object
If laser beams of different colors are combined, then the service life is extended, but speckle effects increase affecting projection quality
Solution Approach 1:
The patent segments the laser beams by polarization direction before they enter the combining lens group. By separating beams of different colors into different polarization channels, the system reduces coherence overlap between beams, thereby minimizing speckle effects while still achieving color combination for extended service life
Solution Approach 2:
The patent changes the polarization parameter of the laser beams as a means of separation. By adjusting polarization directions to be orthogonal for different colors, the system modifies the optical parameters to reduce interference and speckle effects, improving projection quality while maintaining the benefits of multi-color combination
3Stability of the object's composition
If the beam expanding component increases divergence angle, then the beam homogeneity is improved, but the beam path complexity increases
Solution Approach 1:
The patent merges the beam expanding function with the polarization separation function in a compact arrangement. The beam expanding component is positioned to work in conjunction with the polarization-based beam separation, achieving both homogeneity improvement and path simplification by combining multiple functions into an integrated optical path
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 provides improved luminance, extended service life, reduced power consumption, and enhanced projection quality by optimizing beam combination and speckle reduction, resulting in a superior display experience.
Implementation Method 1
The beam expanding component is located on a laser-exit beam path of the first type laser beam and configured to increase a divergence angle of the first type laser beam
Implementation Method 2
Any one of the plurality of combining lens groups is configured to combine incident laser beams and output the combined laser beams towards a beam outlet of the laser source
Implementation Method 3
The polarization conversion component is located on a beam-combining path of the laser beams of the plurality of colors emitted by the plurality of laser devices. The polarization conversion component is configured to change a polarization direction of a portion of the laser beams of the plurality of colors
Data Source
AI summary
A laser source and laser projection apparatus. The laser source includes a plurality of laser devices, a beam expanding component, a plurality of combining lens groups, and a polarization conversion component. The plurality of laser devices are configured to emit laser beams of a plurality of colors to provide white beams. The beam expanding component is located on a laser-exit beam path of the first type laser beam. The plurality of combining lens groups are respectively located on laser-exit sides of the plurality of laser devices. A plurality of laser-exit beam paths corresponding to the plurality of combining lens groups do not overlap with each other. The polarization conversion component is located on a beam-combining path of the laser beams of the plurality of colors. The polarization conversion component is configured to change a polarization direction of a portion of the laser beams.