Speckle Reduction Mask Using Electrically Controllable Cells
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Solution Overview
Problem
Existing speckle reduction techniques, such as mechanical vibration and multiple laser sources, are impractical due to high power requirements and mechanical complexity, limiting effective speckle reduction in laser display systems.
Innovation Solution
A speckle reduction apparatus with an array of electrically controllable cells forming patterns that vary over time, allowing for stationary operation and reduced mechanical components, using orthogonal arrays or Hadamard matrices to create independent speckle patterns that can be averaged out within the integration time of a detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mechanical vibration is used to reduce speckle, then speckle contrast is reduced, but the device complexity and power requirements increase
Solution Approach 1:
The patent replaces the mechanical vibration system with an electrically controllable mask that can be programmed to display different patterns. Instead of physically moving or vibrating components, the invention uses electrical control of mask cells to generate multiple independent speckle patterns, thereby eliminating complex mechanical actuators while achieving speckle reduction.
Solution Approach 2:
The patent introduces an electrically controllable mask as an intermediary element between the laser source and the screen. This mask acts as a mediator that modulates the light field to create independent speckle patterns through electrical control, avoiding direct mechanical intervention in the optical path.
2Object-affected harmful factors
If Hadamard Matrix phase mask is mechanically moved to create independent speckle patterns, then speckle reduction is achieved, but the device complexity and power requirements increase
Solution Approach 1:
The patent replaces the mechanical movement of the Hadamard Matrix phase mask with electrical control of mask cells. The mask remains stationary while its transmission properties are dynamically changed through electrical actuation, eliminating the need for high-power mechanical actuators while maintaining the ability to generate independent speckle patterns.
Solution Approach 2:
The patent introduces temporal dynamics through electrical control rather than mechanical movement. The mask cells can be switched on and off or adjusted in transmission properties in real-time, creating dynamic speckle patterns without physical displacement. This allows for high-speed pattern switching with minimal power consumption.
3Object-affected harmful factors
If multiple laser sources are used to reduce speckle, then speckle contrast is reduced, but the device complexity and cost increase
Solution Approach 1:
The patent segments the single laser beam into multiple independent speckle patterns through the electrically controllable mask. Instead of using multiple laser sources, the mask divides the single laser output into N independent speckle patterns that are superimposed on the screen, achieving speckle reduction while maintaining a simple single-source illumination system.
Solution Approach 2:
The patent transitions from spatial diversity (multiple laser sources) to temporal diversity (time-varying mask patterns). By modulating the mask in time, the system creates multiple independent speckle patterns from a single spatial source, effectively adding a temporal dimension to the speckle reduction approach while avoiding the complexity of multiple simultaneous sources.
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 creating multiple independent speckle patterns without the need for mechanical movement, achieving higher theoretical speckle suppression with fewer electrodes and simpler electrical control, making it more practical and cost-effective.
Implementation Method 1
the mask comprising an array of electrically controllable cells configured to form a pattern on the mask that varies with time
Implementation Method 2
Interference of these de-phased but coherent wavelets results in the granular pattern known as speckle
Data Source
AI summary
Speckle reduction apparatus includes a radiation path and a mask arranged within the radiation path. The mask includes an array of electrically controllable cells configured to form a pattern on the mask that varies with time. The speckle reduction mask includes a first linear array including first parallel lines arranged to change the phase of incident radiation, and a second linear array including second parallel lines arranged to change the phase of incident radiation and further arranged such that cells are formed at the intersections of the first parallel lines and the second parallel lines. The speckle reduction mask includes a N1×N2 array of cells, A, formed according to:ATA=βδk,l,where AT is the transpose of A, β is a real and positive constant, dk,l is Kronecker delta and N1≠N2.