Beam Diffusing Module Redistributes Laser M Squared to Reduce Speckle
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Solution Overview
Problem
Highly coherent laser beams produce speckles when irradiating unsmooth surfaces due to interference, leading to uneven illumination and reduced optical quality in applications like touch panels and OLEDs, where surface microstructures cause irregular noise-like patterns.
Innovation Solution
A beam diffusing module with reflective plates and microstructures that redistribute the laser beam's M squared parameter along a specific direction, using reflective surfaces with divergence angles and microstructures to mitigate speckle formation by adjusting the beam's energy distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a highly coherent laser beam is used to irradiate unsmooth object surfaces, then high power and high light intensity are achieved, but speckles are produced due to interference, leading to uneven illumination and reduced optical quality
Solution Approach 1:
The reflective surface is segmented into multiple reflective microstructures (microlenses or microprisms) that divide the incident laser beam into multiple sub-beams. These sub-beams are reflected in different directions, effectively segmenting the coherent light path and reducing interference patterns that cause speckles.
Solution Approach 2:
The reflective microstructures are nested within the beam diffusing module, with each microstructure containing and redirecting a portion of the laser beam. The nested arrangement allows multiple reflection events within a compact structure, progressively diffusing the beam to eliminate speckles while maintaining high power output.
2Illumination intensity
If a laser beam with high coherence is used, then high light intensity is achieved, but uneven illumination occurs on the irradiation surface due to interference patterns
Solution Approach 1:
Different regions of the reflective surface have different local qualities through the arrangement of reflective microstructures. Each microstructure is designed with specific geometric properties to redirect light locally, creating a cumulative effect that produces uniform overall illumination while maintaining high intensity.
Solution Approach 2:
The reflective microstructures introduce a new dimension of light control by redirecting beams in three-dimensional space rather than simple planar reflection. This dimensional transformation of the light path distributes illumination more uniformly across the target surface.
3Manufacturing precision
If reflective surfaces with microstructures are used to diffuse the laser beam, then speckle phenomena are reduced and illumination uniformity is improved, but the device complexity increases
Solution Approach 1:
The beam diffusing module merges multiple reflective microstructures into a single integrated component. By combining the diffusing function with the reflective surface in one element, the design reduces the number of separate optical components needed, thereby simplifying the overall system despite the microstructured surface.
Solution Approach 2:
The reflective microstructures are designed with specific geometric parameters (size, shape, spacing, orientation) that can be optimized to achieve the desired beam diffusion effect. By carefully controlling these parameters, the module achieves effective speckle reduction with a relatively simple overall structure.
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 reduces speckle phenomena, enhancing the uniformity of the laser beam's intensity and improving the optical quality by redistributing the beam's energy, maintaining the distribution along the perpendicular direction unchanged.
Implementation Method 1
The first reflective plate has a first reflective surface, and the first reflective plate is disposed on a transmission path of the laser beam... The second reflective plate has a second reflective surface, and the second reflective plate is disposed on the transmission path of the laser beam... At least one of the first reflective surface of the first reflective plate and the second reflective surface of the second reflective plate has a plurality of reflective microstructures.
Implementation Method 2
The reflective microstructures are arranged along a second direction from the light incident terminal towards the light emitting terminal... to cause an M squared of the laser beam emitted from the beam diffusing module to be redistributed along the first direction. The beam diffusing module complies with θm≥θm0, where θm0 is an original divergence angle of the laser beam.
Data Source
AI summary
A beam diffusing module including a light incident terminal, a light emitting terminal, a first reflective plate and a second reflective plate is provided. The first reflective plate and the second reflective plate are disposed on a transmission path of a laser beam. At least one of the first reflective plate and the second reflective plate has a plurality of reflective micorstructures. The reflective micorstructures are arranged along a second direction from the light incident terminal towards the light emitting terminal. At least a part of the laser beam enters the beam diffusing module through the light incident terminal and emerges from the light emitting terminals after being reflected repeatedly by the first reflective plate and the second reflective plate to cause an M squared of the laser beam to be redistributed along a first direction. A beam generating system is also provided.