Laser Illumination Spatial Multiplexing for Projector Optical Path
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Solution Overview
Problem
Existing projector technologies using dichroic mirrors for combining laser beams face challenges such as complexity in coating requirements, precision assembly issues, and limitations in combining beams with the same or similar wavelengths, leading to light loss and unequal path lengths.
Innovation Solution
The use of spatial multiplexing to combine laser beams using broadband mirrors or turning prisms, allowing for flexible placement and combination of lasers with similar or identical wavelengths, and simplifying the optical path by making beams parallel with collimating lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If dichroic mirrors are used to combine laser beams, then beam combination is achieved, but device complexity and manufacturing cost increase due to complex coating requirements
Solution Approach 1:
The patent extracts the wavelength-selective function from complex dichroic mirror coatings and relocates it to the laser sources themselves. By using lasers with inherently different wavelengths (red, green, blue) and positioning them at different locations in the illumination module, the system eliminates the need for complex dichroic coatings while maintaining the beam combination function.
Solution Approach 2:
The patent replaces expensive, precision-manufactured dichroic mirrors with simpler, more cost-effective components. The solution uses standard optical elements like beam combiners and diffusers combined with separately positioned laser sources, reducing manufacturing complexity and cost while achieving the same functional result.
2Loss of energy
If dichroic mirrors are used to combine laser beams, then beam combination is achieved, but light loss occurs due to precision assembly issues and center seam problems
Solution Approach 1:
The patent segments the laser sources spatially, positioning red, green, and blue lasers at different locations within the illumination module rather than attempting to combine beams through a single complex dichroic mirror assembly. This segmentation eliminates the center seam problem and reduces the precision requirements for assembly, as each laser can be independently positioned and aligned.
Solution Approach 2:
The patent introduces a beam combiner and diffuser as intermediary elements that facilitate the combination of light from separately positioned lasers. These intermediaries enable efficient light combination without requiring the lasers to be precisely co-located, thereby reducing light loss while maintaining manufacturing feasibility.
3Adaptability or versatility
If dichroic mirrors are used to combine laser beams, then beam combination is achieved, but adaptability is limited due to inability to combine beams with same or similar wavelengths
Solution Approach 1:
The patent creates a universal illumination module design that can accommodate multiple laser sources with different wavelengths (red, green, blue) positioned at different locations. The modular architecture with separate laser mounting positions and a common beam combining mechanism enables the system to be adapted to various laser configurations and wavelength combinations without requiring complex wavelength-specific optical paths.
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 approach reduces the complexity and cost of dichroic mirrors, enables efficient combination of lasers with similar wavelengths, and provides flexibility in laser placement, improving light utilization and optical layout simplicity.
Implementation Method 1
at least two laser sources, the light output of which is combined by spatial multiplexing
Implementation Method 2
A projector includes a plurality of laser sources (100, 101, 102) arranged at right angles to one another. Each laser source emits a laser beam (70) of a different color wavelength. The laser beams are converted into parallel beams of light by a use of three collimating lenses (42a, 42b, 42c).
Implementation Method 3
The light from laser 12 is reflected off a mirror 25, toward the first dichroic mirror 26
Data Source
AI summary
An optical system has projector optics aligned on a projection axis that is orthogonal to an offset axis. A first laser is positioned in a first plane orthogonal to the projection axis. First folding optics are positioned in the first plane to fold a first beam from the first laser to a first portion of the projector optics. A second laser is in a second plane parallel to, and offset along the offset axis from, the first plane. Second folding optics is positioned in the second plane to fold a second beam from the second laser to a second portion of the projector optics to synthesize the first and second beam.