Vibrating Display Screen Eliminates Laser Speckle Noise
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Solution Overview
Problem
Laser-based image display systems suffer from speckle noise due to coherent light interference on uneven surfaces, causing discomfort and image quality degradation.
Innovation Solution
An image display system with at least one actuator attached to a surface of an image display element, vibrating the surface with a vibration signal to change the light wavefront and phase frequency, preventing constructive/destructive interference patterns and thus eliminating speckle, while also allowing for simultaneous sound production through audible or ultrasonic vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If laser light is used as a light source for projection, then optical efficiency and color reproduction are improved, but speckle noise is generated causing image quality degradation
Solution Approach 1:
The patent applies mechanical vibration to the projection screen surface to eliminate speckle noise. The screen is vibrated in the optical path of the projected laser light, causing dynamic changes in the interference pattern of coherent light. This vibration prevents the formation of stable speckle patterns while maintaining the benefits of laser illumination, thereby resolving the contradiction between optical efficiency and speckle noise generation.
2Object-affected harmful factors
If the screen is vibrated to eliminate speckle, then image quality is improved, but additional device components are required
Solution Approach 1:
The patent integrates multiple functions into the projection screen itself. The screen serves both as the image display surface and as the vibration element for speckle elimination. By making the screen itself vibratable rather than adding separate vibration mechanisms, the system achieves speckle reduction without significantly increasing device complexity, demonstrating multi-functionality principle.
3Use of energy by moving object
If coherent light is used for display, then directivity and optical efficiency are improved, but interference patterns cause observer discomfort
Solution Approach 1:
The patent uses mechanical vibration of the projection screen to disrupt the coherence of reflected light. By vibrating the screen surface during projection, the optical path length varies dynamically, causing the interference patterns to fluctuate and average out over time. This eliminates the harmful interference effects while preserving the high optical efficiency of coherent laser light.
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
Effectively eliminates speckle noise in projected images and enables sound production, enhancing observer comfort and image quality without speckle patterns.
Implementation Method 1
The surface of the image display element is vibrated using a vibration signal, so that the wavefront of light originally transmitted from the surface is constantly changing
Implementation Method 2
light of a single wavelength that is scattered at each point on a rough surface overlaps irregularly at each point on the observed surface to produce a complicated interference pattern
Implementation Method 3
when the vibration signal is generated from an audio signal, audible sound can also be produced through the surface of the image display element by vibrating the image display element using the vibration signal having an audible frequency
Data Source
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AI summary
An image display system includes a projector, an image display element, and at least one actuator. The projector is configured to project laser light. The image display element is configured to display an image using the projected laser light. The at least one actuator is configured to vibrate the image display element.