Closed Loop Projector Driving with Phase and Amplitude Modulation
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Solution Overview
Problem
Current projectors using light valve technology suffer from inefficiencies in light energy usage and reduced contrast ratio due to wasted light and imperfect light blocking, making it difficult to achieve High Dynamic Range (HDR) without increasing average brightness, which can be painful for viewers.
Innovation Solution
A projector system with a phase modulator and at least one amplitude modulator, utilizing a closed-loop driving mechanism with an image sensor to provide real-time feedback, compensating for errors in light steering and optimizing light distribution to enhance dynamic range and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light valve technology is used to block light for black levels, then contrast ratio is improved, but light energy is wasted and average brightness increases
Solution Approach 1:
The invention divides the light modulation function into two separate components: a phase modulator that redirects light without absorbing it, and an amplitude modulator that selectively blocks light. This segmentation allows the system to achieve high contrast ratios through the amplitude modulator while the phase modulator efficiently directs light energy, preventing waste and avoiding unnecessary increases in average brightness.
Solution Approach 2:
The phase modulator acts as an intermediary device between the light source and the amplitude modulator. It redirects light from regions where it is not needed to regions where it is required, thereby optimizing light distribution before the amplitude modulator performs the blocking function. This intermediary role improves overall system efficiency by reducing light energy waste while maintaining the contrast ratio enhancement.
2Illumination intensity
If peak brightness is increased for HDR, then dynamic range is improved, but black level is raised and light energy is wasted
Solution Approach 1:
The phase modulator performs preliminary light redistribution before the light reaches the amplitude modulator. By pre-positioning light in the correct spatial locations, the system can achieve high peak brightness in highlighted areas without needing to increase overall illumination levels. This preliminary action ensures that light energy is used efficiently, avoiding waste while enabling HDR-capable peak brightness levels.
Solution Approach 2:
The system applies different light intensities to different spatial locations: the phase modulator concentrates light locally in highlight regions to achieve high peak brightness, while the amplitude modulator maintains low light levels in other regions to preserve black levels. This local quality differentiation enables HDR performance without increasing average brightness or wasting light energy.
3Productivity
If phase modulator is used for light steering, then light distribution efficiency is improved, but manufacturing precision and calibration complexity increase
Solution Approach 1:
The system incorporates feedback mechanisms that measure the actual light distribution pattern produced by the phase modulator and use this information to adjust and optimize its operation. This feedback loop compensates for manufacturing tolerances and calibration variations, enabling the system to achieve high light distribution efficiency without requiring extremely tight manufacturing precision.
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 extends the dynamic range in both black and white without significant increases in laser power, reducing image artefacts and ensuring accurate, safe light levels for viewers.
Implementation Method 1
a phase modulator configured to receive incident illumination and generate a highlight image incident on the amplitude modulator
Implementation Method 2
at least one amplitude modulator configured to modulate an amplitude of the highlight image
Data Source
Figure 1
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Figure 4
AI summary
A method for driving a projection system and a projection system comprising a phase modulator and at least one amplitude modulator are described. The phase modulator is configured to generate a highlight image incident on the amplitude modulator, the projector system further comprises at least one image sensor configured to receive at least a portion of an illumination pattern substantially equivalent to the illumination pattern incident on the amplitude modulator, and the image sensor is being used to provide feedback to the controller of the projection system to improve the highlights projected by the projection system.