Modal-noise mitigator for laser projectors
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Solution Overview
Problem
Laser-based digital projectors suffer from image artifacts due to modal noise in multimode optical fibers, leading to non-uniform luminance regions that degrade image quality.
Innovation Solution
A modal-noise mitigator is introduced, comprising an actuator and an elastic coupler that applies a time-varying mechanical force to the multimode optical fiber, altering its cross-sectional shape, curvature, or refractive index to scramble and randomize the modal noise, thereby reducing its perceivability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser-based digital projectors use multimode optical fibers to deliver light, then the projectors achieve enhanced picture quality and longer life, but modal noise introduces artifacts and non-uniform luminance regions that degrade image quality
Solution Approach 1:
The patent applies mechanical vibration to the multimode optical fiber through an actuator that generates time-varying mechanical forces. This vibration randomly modulates the fiber's cross-sectional shape, curvature, and refractive index, causing modal noise patterns to change rapidly over time. The human visual system integrates these rapid fluctuations, perceiving a more uniform image rather than distinct artifacts.
Solution Approach 2:
The invention transforms the static fiber configuration into a dynamic system where the fiber's physical properties (shape, curvature, refractive index) continuously change in response to applied mechanical forces. This dynamic modulation scrambles the modal noise patterns, preventing stable artifact formation and improving perceived image uniformity while maintaining the reliability benefits of laser sources and multimode fibers.
2Manufacturing precision
If mechanical forces are applied to the optical fiber to scramble modal noise, then image uniformity improves, but excessive force may damage the fiber's mechanical integrity
Solution Approach 1:
The patent carefully controls the parameters of applied mechanical forces, using time-varying forces with amplitudes and frequencies that are sufficient to scramble modal noise patterns but remain below thresholds that would cause fiber damage. The actuator applies forces in the range that modifies the fiber's cross-sectional shape and curvature without exceeding the fiber's mechanical strength limits.
Solution Approach 2:
The invention introduces an elastic coupler as an intermediary between the actuator and the optical fiber. This coupler transmits mechanical forces from the actuator to the fiber while providing mechanical isolation and protection, ensuring that forces are distributed evenly and never concentrated to damaging levels. The coupler acts as a buffer that protects the fiber from excessive forces while still transmitting sufficient force to achieve modal noise scrambling.
3Object-affected harmful factors
If time-varying mechanical forces are applied to alter fiber properties, then modal noise is randomized and perceivability reduces, but system complexity increases due to the actuator and control mechanisms
Solution Approach 1:
The patent employs self-service principles where the actuator and elastic coupler form a self-contained modal noise mitigation unit that can be integrated into existing projector systems. The device uses simple mechanical components rather than complex electronic control systems, and the time-varying forces are generated through straightforward actuation mechanisms that do not require sophisticated control algorithms or feedback systems.
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 mitigates modal noise, making the image quality more uniform and reducing artifacts, with the actuator's frequency and force configuration ensuring minimal impact on the fiber's mechanical integrity and image stability.
Implementation Method 1
an actuator configured to apply a time-varying mechanical force to a fiber segment of the multimode optical fiber in at least a first direction orthogonal to a fiber axis of the multimode optical fiber within the fiber segment
Implementation Method 2
an elastic coupler configured to apply the time-varying mechanical force from the actuator to the fiber segment of the multimode optical fiber
Data Source
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AI summary
A method for mitigating modal noise includes applying a time-varying mechanical force to a fiber segment of the multimode optical fiber in at least a first direction orthogonal to a fiber axis of the multimode optical fiber within the fiber segment. A modal-noise mitigator for a multimode optical fiber includes an actuator configured to apply a time-varying mechanical force to a fiber segment of the multimode optical fiber in at least a first direction orthogonal to a fiber axis of the multimode optical fiber within the fiber segment.