Beam-Split Blue Laser Light Source for Low-Speckle Projection
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Solution Overview
Problem
Laser speckle interference and narrow color gamut in projection systems using laser light sources cause image noise and eye damage, respectively.
Innovation Solution
A dual blue laser light source with differing wavelengths and polarizations is used to split laser light, combined with a phosphor mechanism to generate fluorescence, reducing speckle contrast and expanding color gamut through beam splitting and polarization management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single blue laser source is used to generate blue light, then the laser provides low energy consumption and long service life, but laser speckle interference causes image noise
Solution Approach 1:
The patent divides the single blue laser source into two separate blue laser sources with different wavelengths (first blue laser light and second blue laser light). This segmentation allows the system to combine multiple laser beams that do not produce coherent interference patterns, thereby reducing speckle while maintaining the reliability and efficiency benefits of laser illumination.
Solution Approach 2:
The patent merges the output of two blue laser sources with different wavelengths and polarizations, combining them with fluorescence from a phosphor mechanism. This merging creates a composite blue light that maintains laser advantages while suppressing speckle through wavelength and polarization diversity.
2Object-generated harmful factors
If ultraviolet light is used to excite phosphor for blue fluorescence, then speckle of blue laser light is suppressed, but the excitation color gamut becomes narrow and ultraviolet light may cause damage to human eyes
Solution Approach 1:
The patent changes the excitation parameter from ultraviolet wavelength to blue laser wavelength. By using blue laser light (with specific wavelengths) to excite the phosphor mechanism, the system achieves speckle suppression through the combination of direct blue laser light and phosphor-generated blue fluorescence, while avoiding the harmful effects of ultraviolet radiation and expanding the color gamut.
3Object-generated harmful factors
If multiple blue laser sources with different wavelengths and polarizations are used, then speckle contrast is reduced, but device complexity increases
Solution Approach 1:
The patent introduces a beam splitting module as an intermediary component that divides the second blue laser light into two paths: one path provides direct blue laser light, and the other path directs light to the phosphor mechanism. This intermediary structure enables the complex multi-wavelength, multi-polarization light source configuration while maintaining manageable system architecture and optical path control.
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
Effective speckle suppression and enhanced color gamut are achieved by minimizing laser interference and adjusting chromaticity coordinates, ensuring clear and vibrant image projection.
Implementation Method 1
A first blue light source is configured to output first blue laser light
Implementation Method 2
A second blue light source is configured to transmit second blue laser light to a beam splitting module
Implementation Method 3
The beam splitting module is configured to: split the second blue laser light to obtain first sub-laser light and second sub-laser light
Implementation Method 4
The phosphor is configured to: obtain fluorescence under excitation of the second sub-laser light
Implementation Method 5
The phosphor is configured to: obtain fluorescence under excitation of the second sub-laser light
Implementation Method 6
The light source is configured to output a projection light beam. The projection light beam includes the first blue laser light, the first sub-laser light, and the fluorescence
Data Source
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AI summary
A light source, a projection system, a projection method, and a related apparatus are provided, to effectively implement speckle suppression and reduce a speckle contrast. The light source includes a first blue light source (101) configured to emit first blue laser light (111), a second blue light source (102) configured to emit second blue laser light (112), a beam splitting module (103), and a phosphor (104). The beam splitting module (103) splits the second blue laser light (112) to obtain first sub-laser light (113) and second sub-laser light (114). A wavelength and a polarization of the first sub-laser light (113) are different from those of the first blue light source (101), to suppress a speckle of blue laser light. The second sub-laser light (114) is used to excite the phosphor (104) to obtain fluorescence (115). The projection system performs projection imaging based on the first sub-laser light (113), the first blue laser light (111), and the fluorescence (115).