LCoS Projection Apparatus Speckle Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Speckle contrast is high in holographic displays using liquid crystal on silicon (LCoS) panels, resulting in non-uniform reconstructed images due to constructive and destructive interference patterns.
Innovation Solution
A projection apparatus with a liquid crystal on silicon panel and a processor that generates and displays multiple phase images with inverted intensity distributions and rearranged pixel phases, compensating speckle brightness and locations to reduce speckle contrast, and adjusts illumination beam intensity for each phase image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single phase image is projected using LCoS panel, then the projection process is simple and fast, but the speckle contrast is high and the reconstructed image is non-uniform
Solution Approach 1:
The patent applies periodic action by projecting multiple phase images (at least two) in sequence within a single frame period. The processor generates first and second phase images with different phase distributions, displays them alternately on the LCoS panel, and combines them to form the final reconstructed image. This periodic switching between different phase images reduces speckle contrast while maintaining projection speed, as the human eye integrates the rapidly alternating images into a single uniform perception.
2Ease of operation
If multiple phase images are projected to reduce speckle contrast, then the reconstructed image becomes uniform, but the processing complexity increases
Solution Approach 1:
The patent applies inversion by generating phase images with inverted intensity distributions. Specifically, the processor creates a second phase image where the phase distribution is the inverse of the first phase image. This inversion approach ensures that bright speckles in one image correspond to dark speckles in the other, and when combined, they cancel out to produce a uniform reconstructed image with reduced speckle contrast, thereby simplifying the overall processing requirement.
3Ease of operation
If multiple phase images with different intensities are projected, then speckle brightness is compensated and uniformity is improved, but the illumination control complexity increases
Solution Approach 1:
The patent applies feedback by adjusting the illumination beam intensity based on the phase image being displayed. The controller modifies the illumination intensity dynamically - using higher intensity for phase images with darker regions and lower intensity for phase images with brighter regions. This feedback-based illumination control compensates for speckle brightness variations, ensuring uniform contribution from each phase image to the final reconstructed image, thereby improving overall uniformity without requiring complex additional hardware.
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 contrast and achieves a more uniform reconstructed image by temporally projecting multiple phase images with different phases within a single frame period, improving image quality.
Implementation Method 1
The liquid crystal on silicon panel is configured to display a plurality of phase images. The processor generates the first phase image according to a first phase information, and the processor generates the second phase image according to the first phase image.
Implementation Method 2
The liquid crystal on silicon panel converts the illumination beam into an image beam and output the image beam. The image beam comprises the phase images.
Implementation Method 3
The processor inverts an intensity distribution of the first phase image to generate the second phase image. The intensity distribution of the second phase image is inverted from the intensity distribution of the first phase image.
Implementation Method 4
For the holographic display using LCoS, it use light diffraction to form image. The formation of diffraction image is the reconstruction of constructive and destructive interference.
Implementation Method 5
The formation of diffraction image is the reconstruction of constructive and destructive interference. When a laser beam incidents on LCoS, the diffraction image is reconstructed at a certain distance.
Data Source
AI summary
A projection apparatus including a liquid crystal on silicon panel and a processor is provided. The liquid crystal on silicon panel is configured to display a plurality of phase images. The phase images include a first phase image and a second phase image. The processor is coupled to the liquid crystal on silicon panel. The processor is configured to generate and output the phase images to drive the liquid crystal on silicon panel to display the phase images. The processor generates the first phase image according to a first phase information, and the processor generates the second phase image according to the first phase image.