Rotating Light Diffusion Element for Laser Speckle Reduction
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Solution Overview
Problem
Projectors using laser or LED light sources often suffer from speckle noise due to high coherence, leading to unpleasant glare and image distortion, with existing solutions not effectively removing speckles or providing consistent results.
Innovation Solution
A light source apparatus with a rotating light diffusion element featuring multiple diffusion regions with distinct diffusion characteristics, changing the incidence angle distribution of image light over time to superimpose different speckles, reducing their visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a laser light source with narrow wavelength range is used to achieve wide color reproduction and miniaturization, then color reproduction range is improved and device size is reduced, but speckle noise increases due to high light coherence
Solution Approach 1:
The light diffusion element is divided into multiple diffusion regions (first diffusion region, second diffusion region, etc.) with different diffusion characteristics. Each region independently diffuses light with different diffusion angles or directions, segmenting the coherent laser light into multiple incoherent paths that reduce speckle noise while maintaining color reproduction quality
Solution Approach 2:
Different regions of the light diffusion element are given different local diffusion characteristics (different diffusion angles, directions, or patterns). This local quality variation ensures that light from different regions contributes differently to the final image, reducing the visibility of speckle patterns while preserving the narrow wavelength range benefits of laser light
2Object-affected harmful factors
If a light diffusion element with multiple diffusion regions having different diffusion characteristics is used to reduce speckle noise, then speckle visibility is reduced, but device complexity increases
Solution Approach 1:
Multiple diffusion regions with different diffusion characteristics are integrated into a single light diffusion element that rotates as one unit. This merging approach combines the speckle-reduction functionality of multiple regions without requiring separate diffusion elements or complex switching mechanisms, thus reducing overall device complexity
Solution Approach 2:
The light diffusion element is designed to rotate, dynamically switching between different diffusion regions. This dynamic operation allows a single element to provide multiple diffusion characteristics over time, reducing speckle noise without requiring multiple static elements or complex mechanical structures
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 noise, allowing for the display of high-quality images with fewer speckles by dynamically altering the diffusion angle and light distribution, improving illumination efficiency and image clarity.
Implementation Method 1
a light diffusion element that is provided so as to be rotated about a predetermined rotation shaft and includes a plurality of diffusion regions which are consecutively formed around the rotation shaft
Implementation Method 2
light interference occurs in a scatterer such as a screen, and thus a phenomenon of a so-called speckle may occur
Data Source
AI summary
A light source apparatus includes a light source unit, a light diffusion element that is provided so as to be rotated about a predetermined rotation shaft and includes a plurality of diffusion regions which are consecutively formed around the rotation shaft, and a motor that rotates the light diffusion element so that a region on which light from the light source unit is incident in the light diffusion element is moved between the plurality of diffusion regions. The plurality of diffusion regions include a first diffusion region, and a second diffusion region which has diffusion characteristics different from diffusion characteristics of the first diffusion region and is provided so as to be adjacent to the first diffusion region.