Spatial Light Modulator Wavefront Compensation for Projection Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Digital projection systems face issues with low frequency and DC-noise due to irregularities in optical components, such as cover glasses, which introduce amplitude and phase variations in the optical wavefront, leading to noise visible at the reconstruction plane.
Innovation Solution
A system and method that utilize a spatial light modulator with a transparent material layer and phase modulation layer, combined with phase-shifting holography, to derive and compensate for the attenuating wavefront, reducing noise by adjusting the phase-drive signal to destructively interfere with noise wavefronts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical components such as cover glasses are used in the projection system, then the system can function properly with light modulation and projection capabilities, but low frequency and DC-noise are introduced due to irregularities in the optical components causing amplitude and phase variations in the optical wavefront
Solution Approach 1:
The patent measures the noise wavefront introduced by the cover glass and uses phase-shifting holography to generate a compensating wavefront that destructively interferes with the noise. This converts the harmful noise effect into a beneficial cancellation mechanism, where the measured noise pattern becomes the basis for creating its opposite to achieve noise suppression
Solution Approach 2:
The system measures the actual noise wavefront produced by the cover glass using an imaging device, processes this measurement to determine a compensating phase pattern, and feeds this information back to the spatial light modulator. This closed-loop feedback enables dynamic compensation of the noise introduced by optical components
2Object-generated harmful factors
If phase-shifting holography is used to measure and compensate for the attenuating wavefront, then low frequency noise can be effectively reduced, but the device complexity and processing requirements increase
Solution Approach 1:
The projection system uses its own spatial light modulator and imaging device to perform the noise measurement and compensation without requiring external specialized equipment. The SLM serves dual purposes: normal projection function and noise compensation application, while the imaging device captures both the noise pattern and the compensation effect, making the system self-sufficient
Solution Approach 2:
The spatial light modulator is used for multiple functions: normal image projection, noise wavefront measurement, and noise compensation application. The imaging device similarly serves multiple purposes including capturing the projected image and measuring the noise wavefront. This multi-functionality reduces the need for additional dedicated components
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
Effectively attenuates low-frequency noise, improving image projection quality and reducing artifacts in digital projection systems, applicable beyond projection systems to other noise reduction needs like microscopy and telecommunications.
Implementation Method 1
a spatial light modulator with a transparent material layer and phase modulation layer
Implementation Method 2
adjusting the phase-drive signal to destructively interfere with noise wavefronts
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A system and method comprise a light source; a spatial light modulator including a substantially transparent material layer and a phase modulation layer; an imaging device configured to receive a light from the light source as reflected by the spatial light modulator, and to generate an image data; and a controller. The controller provides a phase-drive signal to the spatial light modulator and determines an attenuating wavefront of the substantially transparent material layer based on the image data.