Compact Laser Source Assembly for Speckle Reduction
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Solution Overview
Problem
Current laser projection technologies face challenges in miniaturization due to the large volume of laser source assemblies, which are often bulky and occupy significant space, and suffer from speckle effects that degrade image quality.
Innovation Solution
The proposed laser projection apparatus incorporates a compact laser source assembly with multiple laser devices emitting three colors (blue, green, and red) that are combined using dichroic elements and a fly-eye lens for homogenization, and includes a diffusion plate to reduce speckle effects by increasing the divergence angle of the laser beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional laser source assemblies are used, then laser beams can be provided for projection, but the volume of the laser source assembly becomes large and occupies significant space
Solution Approach 1:
The laser source assembly is segmented into multiple independent laser devices (blue laser device, green laser device, red laser device) that can be separately positioned and optimized. Each laser device has its own beam combining path, allowing for compact arrangement while maintaining beam quality through individual optimization of each segment.
Solution Approach 2:
The patent uses a three-dimensional spatial arrangement where laser beams from different devices are combined in the optical path using dichroic mirrors and beam combining lenses. The laser devices are positioned at different spatial locations (above, below, left, right of the optical axis) to achieve compact integration while maintaining beam quality through precise optical path control.
2Device complexity
If laser beams are directly projected without homogenization, then the system remains simple, but speckle effects occur that degrade image quality
Solution Approach 1:
A fly-eye lens is introduced as an intermediary component between the beam combining lens group and the projection lens. This fly-eye lens homogenizes the combined laser beams by redistributing the light intensity, effectively reducing speckle effects while maintaining relatively simple system architecture.
Solution Approach 2:
The patent changes the spatial distribution parameters of the laser beams by using the fly-eye lens to homogenize the beam profile. This transforms the concentrated, high-coherence laser beam into a more uniform, speckle-reduced illumination pattern suitable for high-quality projection.
3Manufacturing precision
If beam spots of different colors have different areas on the fly-eye lens, then color-specific optimization is possible, but the optical system becomes more complex
Solution Approach 1:
The fly-eye lens is configured with different sub-lens arrangements for different color regions. Specifically, the lens includes first sub-microlenses for receiving blue and green laser beams, and second sub-microlenses for receiving red laser beams, with different dimensions optimized for each color's beam characteristics. This local optimization achieves color uniformity while using a single integrated fly-eye lens component.
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 reduces the overall volume of the laser projection apparatus, enhances image quality by minimizing speckle effects, and improves luminance and color uniformity of the projected images.
Implementation Method 1
The combining lens group is located on a laser-exit side of the at least one laser device and configured to combine the laser beams emitted by the at least one laser device
Implementation Method 2
The fly-eye lens is located on a laser-exit side of the combining lens group and configured to homogenize the laser beams emitted by the at least one laser device
Implementation Method 3
a diffusion plate is located between the combining lens group and the fly-eye lens and configured to homogenize the incident laser beams
Implementation Method 4
a diffusion plate is located between the combining lens group and the fly-eye lens and configured to homogenize the incident laser beams
Data Source
AI summary
A laser projection apparatus includes a laser source assembly, a light modulation assembly, and a projection lens. The laser source assembly includes a laser device, a combining lens group, and a fly-eye lens. The laser device is configured to emit laser beams of three colors. The laser beams of the three colors includes a blue laser beam, a green laser beam, and a red laser beam. The combining lens group is located on a laser-exit side of the laser device and configured to combine the laser beams emitted by the laser device. The fly-eye lens is located on a laser-exit side of the combining lens group and configured to homogenize the laser beams emitted by the laser device.