Scanning Light Source Speckle Reduction in Pixelated Displays
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Solution Overview
Problem
Existing methods for reducing speckle patterns in displays or projectors using coherent light sources often compromise image quality or are complex in implementation, failing to effectively eliminate bothersome interference patterns.
Innovation Solution
An image-generating unit with a light source and a light-modulating pixel array, where the illumination radiation has a lateral extent smaller than the pixel array, is guided over the pixel array by a scanning unit, superimposing speckle patterns from both components to generate an image point with reduced visibility of speckle patterns without affecting image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If coherent light sources like lasers are used in projectors or displays, then color saturation, performance, efficiency and contrast are improved, but speckle patterns and interference phenomena occur
Solution Approach 1:
The patent applies dynamics by making the illumination beam movable through scanning across the pixel array rather than stationary. The beam is dynamically positioned at different locations corresponding to different pixels, which changes the speckle pattern at each location and reduces the visibility of static speckle artifacts in the final image.
Solution Approach 2:
The scanning process implements periodic action by systematically moving the illumination beam across the pixel array in a regular sequence. This periodic scanning creates time-varying speckle patterns that are averaged by the human eye or detector, effectively reducing the visibility of speckle patterns while maintaining the benefits of coherent light sources.
2Object-generated harmful factors
If existing methods are used to reduce speckle patterns, then speckle visibility is reduced, but image quality is compromised or implementation becomes complex
Solution Approach 1:
The system uses self-service by leveraging the existing scanning functionality required for image generation to simultaneously reduce speckle patterns. The same scanning mechanism that creates the image also dynamically varies the speckle patterns, eliminating the need for separate speckle reduction components or complex additional systems.
Solution Approach 2:
The patent merges the image generation function with the speckle reduction function into a single scanning process. The illumination beam scanning required to create the image is combined with the speckle reduction mechanism, achieving both objectives simultaneously without adding separate systems or compromising image quality.
3Object-generated harmful factors
If existing methods are used to reduce speckle patterns, then speckle visibility is reduced, but implementation complexity increases
Solution Approach 1:
The scanning mechanism serves dual purposes: generating the image and reducing speckle patterns. This self-service approach eliminates the need for additional dedicated speckle reduction components, keeping the implementation simple while effectively reducing speckle visibility.
Solution Approach 2:
The illumination beam scanning system performs multiple functions simultaneously: it generates the image by addressing individual pixels and reduces speckle patterns through dynamic positioning. This multi-functionality simplifies the overall system design by eliminating the need for separate speckle reduction mechanisms.
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
This approach significantly reduces visible speckle patterns in the generated image by combining the inherent variations of the scanning unit and pixel array, maintaining high image quality without the need to reduce light coherence or alter the illumination beam, thus providing a simple and effective solution.
Implementation Method 1
Speckle patterns are in particular the grainy interference phenomena that can be observed with sufficiently coherent illumination of optically rough object surfaces
Implementation Method 2
When laser light is incident on a rough surface—for example when incident on a projection screen—it is reflected at various angles, and the coherent laser light randomly spatially interferes with itself
Data Source
AI summary
The invention preferably relates to an image-generating unit with a light source for generating illumination radiation and a light-modulating pixel array for generating an image by pixel-wise modulation of the illumination radiation incident on the pixel array. The image-generating unit is characterized in that the illumination radiation, upon incidence on the light-modulating pixel array, has a lateral extent which is smaller than the pixel array and is guided over the pixel array by means of a scanning unit for generating an image. By a combination of the process of scanning the illumination radiation over the light-modulating pixel array, the speckle signatures of the scanning unit and of the pixel array are superimposed or combined to generate an image point. Advantageously, visible speckle patterns in the resulting image can thus be significantly reduced.