Laser Display Speckle Reduction via Diffuser Vibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser scanning image display devices face challenges in reducing speckle noise while maintaining high luminance, as methods like vibrating diffusion members at high speeds are impractical and increasing diffusion angles lead to decreased luminance.
Innovation Solution
An image display device with a screen composed of multiple diffusion members, where at least one member is vibrated, and the scanning element scans laser light in two directions with a faster speed in one direction than the other, and a larger beam diameter than scanning intervals, to reduce speckle noise without high-speed vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the diffusion member is vibrated at high speed to reduce speckle, then speckle noise is reduced, but the device becomes practically difficult to implement
Solution Approach 1:
The patent applies dynamics by vibrating the diffusion member in the vertical direction during laser beam scanning. This vibration causes the laser beam to scan multiple lines on the diffusion member, generating multiple speckle patterns that are integrated to reduce speckle noise. The vibration frequency and amplitude are controlled to achieve effective speckle reduction without requiring excessively high speeds, making the device practically implementable.
2Object-affected harmful factors
If the diffusion angle of the diffusion member is increased to reduce speckle, then speckle noise is reduced, but the luminance of the displayed image decreases
Solution Approach 1:
Instead of increasing the diffusion angle which would reduce luminance, the patent uses vertical vibration of the diffusion member during scanning. This dynamic approach generates multiple speckle patterns through repeated scanning of the same region, reducing speckle noise while maintaining the original diffusion angle and thus preserving image luminance.
3Area of stationary object
If the laser beam diameter is increased to cover larger scanning intervals, then the scanning coverage is improved, but the speckle reduction effect is compromised
Solution Approach 1:
The patent employs vertical vibration of the diffusion member during laser scanning. This vibration ensures that even when the laser beam diameter is increased to cover larger scanning intervals, the beam still scans multiple lines on the diffusion member, generating multiple speckle patterns that integrate to reduce speckle noise while maintaining the benefits of larger beam diameter for coverage.
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 device achieves low speckle noise with high luminance by integrating multiple speckle patterns, reducing the need for high-speed vibrations and maintaining image resolution and brightness.
Implementation Method 1
a screen formed of at least two diffusion members which diffuse and transmit the laser light and generate image light
Implementation Method 2
a vibration mechanism vibrating at least one diffusion member in the diffusion members
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An image display device 1 includes a laser light source unit 10, a screen 12 formed of at least two diffusion members, a vibration mechanism 13 vibrating at least one diffusion member, and a scanning element 11 scanning laser light in a first direction (a y direction) on the screen and a second direction (an x direction) orthogonal to the first direction. A scanning speed of the scanning element 11 in the second direction is faster than a scanning speed in the first direction, and a diameter D of the laser light in the first direction on the screen is greater than an interval Yp in the first direction on the scanning trajectory in the second direction on the screen. Accordingly, it is possible to provide an image display device displaying an image having a low speckle with high luminance, without vibrating the diffusion member at a high speed.