Speckle Reduction via Time-Sequential Phase Holograms
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Solution Overview
Problem
Image projection systems using lasers suffer from reduced image quality due to speckles, which are difficult to mitigate in compact environments and holographic projections, as traditional optical diffusers are not feasible.
Innovation Solution
A system employing a spatial light modulator with a controller that generates and updates time-sequential phase holograms, cycling through prism holograms to reduce speckle by applying blurring effects in various directions, enabling efficient speckle reduction without the need for physical diffusers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a rotating or vibrating optical diffuser is used to reduce speckle, then image quality is improved, but power consumption and system complexity increase
Solution Approach 1:
The patent replaces the mechanical rotating or vibrating optical diffuser with a digital micromirror device (DMD) that uses electronic control to achieve speckle reduction. The DMD dynamically adjusts the phase of light waves through electronic signals, eliminating the need for mechanical moving parts while maintaining the speckle reduction effect.
Solution Approach 2:
The patent changes the phase parameter of light waves by controlling the tilt angle of micromirrors on the DMD. By dynamically adjusting the phase parameter through electronic control rather than mechanical movement, the system achieves speckle reduction with lower complexity and power consumption.
2Object-affected harmful factors
If a rotating or vibrating optical diffuser is used to reduce speckle, then image quality is improved, but power consumption increases
Solution Approach 1:
The patent replaces the mechanical rotating or vibrating optical diffuser with a digital micromirror device (DMD) that uses electronic control to achieve speckle reduction. The DMD dynamically adjusts the phase of light waves through electronic signals, eliminating the need for mechanical moving parts while maintaining the speckle reduction effect.
Solution Approach 2:
The DMD system uses the laser light itself to control the micromirror positions, where the incoming light signal directly influences the phase modulation. This self-service approach eliminates the need for external mechanical actuation systems, reducing power consumption.
3Object-affected harmful factors
If an optical diffuser is used to reduce speckle, then image quality is improved, but the system size increases making it unsuitable for compact environments
Solution Approach 1:
The patent replaces the mechanical rotating or vibrating optical diffuser with a digital micromirror device (DMD) that uses electronic control to achieve speckle reduction. The DMD dynamically adjusts the phase of light waves through electronic signals, eliminating the need for mechanical moving parts while maintaining the speckle reduction effect.
Solution Approach 2:
The DMD serves multiple functions: it acts as both the primary spatial light modulator for image formation and the speckle reduction element through phase modulation. This multi-functionality eliminates the need for separate diffuser components, reducing overall system volume.
4Object-affected harmful factors
If an optical diffuser is used to reduce speckle, then image quality is improved, but it cannot be used in holographic projection systems
Solution Approach 1:
The patent replaces the mechanical rotating or vibrating optical diffuser with a digital micromirror device (DMD) that uses electronic control to achieve speckle reduction. The DMD dynamically adjusts the phase of light waves through electronic signals, eliminating the need for mechanical moving parts while maintaining the speckle reduction effect.
Solution Approach 2:
The patent changes the phase parameter of light waves by controlling the tilt angle of micromirrors on the DMD. By dynamically adjusting the phase parameter through electronic control rather than mechanical movement, the system achieves speckle reduction while maintaining compatibility with holographic projection requirements.
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 image speckle by temporal averaging, providing a smooth and consistent image appearance, suitable for high-performance display systems like head-up displays, without increasing power consumption or system complexity.
Implementation Method 1
a spatial light modulator with a display, and a controller. The controller includes processing circuitry configured to control the display of the spatial light modulator to reduce image speckle of a projected image responsive to the laser based on a time sequential update of a plurality of phase holograms
Implementation Method 2
The controller can be configured to cycle through a plurality of prism holograms as an overlay of the phase holograms on the display
Data Source
AI summary
A system includes a laser, a spatial light modulator with a display, and a controller. The controller includes processing circuitry configured to control the display of the spatial light modulator to reduce image speckle of a projected image responsive to the laser based on a time sequential update of a plurality of phase holograms generated responsive to an input frame received at the controller.