Phase Light Modulator Iterative Wave-Propagation Control
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Solution Overview
Problem
Existing projection systems based on phase light modulation face challenges in generating accurate images due to excess or deficit of light at unpredictable locations, leading to artifacts that degrade image quality, and increasing diffuse illumination to address these issues is costly and inefficient.
Innovation Solution
A projection system that includes a light source, a phase light modulator applying spatially-varying phase modulation, and a controller that iteratively determines a reconstruction field, maps it to a modulation field, scales the amplitude, and provides a phase control signal to the modulator, using a wave-propagation loop and regularization to achieve accurate light steering and intensity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light is attenuated to create desired scene levels, then image brightness control is achieved, but light is discarded and energy efficiency deteriorates
Solution Approach 1:
The patent replaces amplitude-based SLMs with phase-only SLMs, substituting a mechanical/optical attenuation system with a phase modulation system. The phase-only SLM modulates only the phase of incident light without attenuating it, thereby eliminating light loss while maintaining image brightness control through interference patterns.
Solution Approach 2:
The invention changes the modulation parameter from amplitude to phase. Instead of controlling light intensity by attenuating amplitude, the system uses phase modulation where the phase of light waves is varied to create constructive and destructive interference, achieving brightness control without energy loss.
2Loss of energy
If phase light modulation is used to steer light, then energy efficiency is improved, but artifacts appear due to excess or deficit of light at unpredictable locations
Solution Approach 1:
The patent implements an iterative feedback algorithm that simulates wave propagation from the SLM to the image plane, compares the simulated result with the target image, and adjusts the phase pattern accordingly. This feedback loop continues until the projected image matches the target, eliminating artifacts caused by light excess or deficit.
Solution Approach 2:
The system performs preliminary simulation of wave propagation and iterative optimization of the phase pattern before actual projection. By pre-calculating the correct phase distribution that will produce the desired image, the system avoids artifacts without needing to increase illumination.
3Manufacturing precision
If diffuse illumination is increased to address light distribution issues, then image quality is improved, but cost and efficiency deteriorate
Solution Approach 1:
The patent uses phase-only modulation to locally control light distribution at the image plane through spatially varying phase patterns. Each region of the image receives precisely the light it needs through constructive interference, eliminating the need for increased diffuse illumination while maintaining image quality.
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 system effectively steers light to accurately reproduce target images with improved quality, reducing artifacts and the need for increased illumination, thereby enhancing image fidelity and operational efficiency.
Implementation Method 1
a phase light modulator configured to receive the light from the light source and to apply a spatially-varying phase modulation on the light, thereby to steer the light and generate a projection light
Data Source
AI summary
A projection system includes a light source configured to emit a light in response to an image data, a phase light modulator configured to receive the light from the light source and to apply a spatially-varying phase modulation on the light, thereby generating a projection light and steering the light on a reconstruction field, wherein the reconstruction field is a complex plane on which a reconstruction image is formed, and a controller configured to control the light source, control the phase light modulator, initialize (401) the reconstruction field to an initial value, and iteratively for each of a plurality of subframes within a frame of the image data: set (402) the reconstruction field to the initial value for the first iteration or set (402) the reconstruction field to a subsequent-iteration reconstruction field value for any subsequent-iteration, map (403) the reconstruction field to a modulation field, wherein the modulation field is a complex plane of the phase light modulator which modulates a phase of the light, set (404) an amplitude of the modulation field to a predetermined value, and map (405) the modulation field with the amplitude set to the predetermined value, to a subsequent-iteration reconstruction field, wherein the controller is further configured to provide (408) a phase control signal based on the modulation field mapped with the last iteration to the phase light modulator.