Speckle Reduction via Interferometer Beam Overlap
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Solution Overview
Problem
Current methods for reducing speckle in laser projection systems require high processing power, are limited by the number of speckle patterns that can be generated, and often result in poor reduction of speckle contrast due to the need for multiple mirrors and limited interference fringes.
Innovation Solution
A method involving multiple interferometers and MEMS mirrors to generate and overlap multiple primary and secondary transmit beams, creating interference fringes that reduce speckle by partially or fully overlapping beam spots on a display surface, with the beams focused to a single point to define image pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple speckle patterns are generated for each pixel using known methods, then speckle reduction is achieved, but processing power requirements increase significantly
Solution Approach 1:
The patent replaces complex computational processing with optical interference mechanisms. By using interferometers to generate multiple transmit beams that interfere constructively and destructively, the system creates multiple speckle patterns through physical optical processes rather than computational methods, thereby reducing processing power requirements while maintaining speckle reduction effectiveness
Solution Approach 2:
The patent changes optical parameters such as beam paths, phase relationships, and interference conditions to generate multiple independent speckle patterns. By varying these parameters through the interferometer configuration, the system produces diverse speckle patterns that when averaged reduce speckle contrast without requiring high processing power
2Object-affected harmful factors
If multiple mirrors are used to generate interference fringes, then speckle reduction is achieved, but device complexity and mirror size requirements increase
Solution Approach 1:
The patent combines multiple beam paths and interferometer configurations into a unified optical system. By merging the functionality of multiple mirrors into a coordinated interferometer arrangement with beam splitters and phase modulators, the system achieves the same speckle reduction effect with reduced component complexity and smaller mirror sizes
Solution Approach 2:
The interferometer components serve multiple functions simultaneously - beam splitting, phase modulation, and interference pattern generation. This multi-functionality reduces the need for separate dedicated components like multiple mirrors, thereby simplifying the overall device complexity
3Object-affected harmful factors
If beam spots are overlapped to generate interference fringes, then speckle contrast is reduced, but focus precision requirements increase
Solution Approach 1:
The patent incorporates feedback mechanisms through phase modulators and detectors that monitor the interference pattern formation. This feedback allows real-time adjustment of beam paths and phases, compensating for minor misalignments and reducing the stringency of focus precision requirements while maintaining effective speckle contrast reduction
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 effectively reduces speckle contrast by generating multiple interference fringes that are averaged by the viewer's eye, improving image quality without the need for large mirrors or high processing power, and allows for automatic focus adjustment.
Implementation Method 1
Interference fringes are light and dark bands produced by the interference and diffraction of light
Implementation Method 2
Interference fringes are light and dark bands produced by the interference and diffraction of light
Implementation Method 3
When the beamlets are recombined interference fringes are produced due to constructive and destructive interference between the beamlets
Data Source
AI summary
According to the present invention there is provided a method of reducing speckle effects in a projected image which is displayed on a display surface, comprising the steps of transmitting an input light beam to a first interferometer, generating a plurality of primary transmit beams at the first interferometer using the input light beam, using the plurality of primary transmit beams to generate interference fringes at a display surface.