Laser Projection Phase Modulation for Local HDR Brightness
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Solution Overview
Problem
Laser projection devices face challenges in adjusting brightness locally to achieve High-Dynamic Range (HDR) display without the ability to divide backlight into regions like liquid crystal displays, leading to inefficiencies in light usage and display quality.
Innovation Solution
Incorporating a phase light modulator to adjust the phase of light output from the light source, combined with a monolithic light modulator, to achieve spatial distribution of light energy, synchronizing the timing sequences of primary colors to enhance peak brightness and reduce dark-field brightness, thereby improving light efficiency and enabling HDR display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a laser projection device uses a single light source to illuminate the entire display area, then the device structure remains simple, but the brightness cannot be adjusted locally to achieve HDR display
Solution Approach 1:
The patent introduces a phase light modulator that divides the uniform light field into multiple independently controllable pixel regions. Each pixel can be modulated individually in the spatial domain, enabling local brightness adjustment without segmenting the physical backlight structure. This resolves the contradiction by achieving regional brightness control through optical field segmentation rather than physical structure segmentation.
Solution Approach 2:
The patent transitions from temporal brightness control (PWM dimming) to spatial brightness control by introducing a phase light modulator. This adds a spatial dimension to brightness adjustment, allowing different regions of the display to have different brightness levels simultaneously, thereby enabling HDR display while maintaining a simple single light source structure.
2Use of energy by moving object
If PWM dimming is used to adjust brightness, then the device structure remains simple, but light energy efficiency is low due to temporal dimming throughout the entire display area
Solution Approach 1:
The patent segments the uniform light field into individually addressable pixel regions through the phase light modulator. This allows the system to illuminate only the necessary regions at full brightness while dimming or turning off other regions, dramatically improving light energy efficiency compared to PWM dimming which dims the entire display area uniformly.
Solution Approach 2:
The patent implements local quality control by enabling each pixel to have independent brightness levels through phase modulation. Different regions can have different optical properties (brightness, phase) simultaneously, allowing the display to optimize light energy usage by providing high brightness only where needed while maintaining dark regions where appropriate, thereby improving overall light energy efficiency.
3Illumination intensity
If the light source intensity is increased to achieve higher peak brightness for HDR, then peak brightness is improved, but the dark-field brightness also increases reducing dynamic contrast
Solution Approach 1:
The patent segments the display into independently controllable pixel regions through phase modulation. This allows the system to simultaneously display high brightness in bright-field regions and low brightness in dark-field regions within the same frame, achieving high dynamic contrast while maintaining high peak brightness capability. The segmentation enables precise local control of brightness levels.
Solution Approach 2:
The patent applies local quality control by enabling different pixels to have different brightness levels through phase modulation. Bright pixels can achieve high peak brightness while dark pixels maintain low brightness levels, creating high dynamic contrast. This resolves the contradiction by allowing peak brightness and dynamic contrast to coexist through spatially varying optical properties.
4Adaptability or versatility
If a phase light modulator is added to enable local brightness adjustment, then HDR display capability is achieved, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical or physical segmentation approaches (such as multiple light sources or regional backlight units) with optical field modulation through a phase light modulator. This substitution achieves HDR capability without the mechanical complexity of physical segmentation, as the phase modulator controls light properties through optical rather than mechanical means.
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 enhances light energy efficiency and improves dynamic contrast in laser projection displays by adjusting brightness locally without altering the light source intensity, resulting in improved display quality.
Implementation Method 1
Incorporating a phase light modulator to adjust the phase of light output from the light source
Implementation Method 2
The light modulator is configured to transmit modulation light based on the modulated light, and the modulation light is configured to form an image beam
Data Source
AI summary
A display drive assembly sends an enable signal and a Pulse Width Modulation (PWM) signal to a laser drive assembly based on a video signal, sends the enable signal to a phase light modulation assembly, and sends a display drive signal to a light modulator. The laser drive assembly sends a light source drive signal to a light source assembly based on the enable signal and the PWM signal, in order to drive the light source assembly to emit one of multiple primary color lights. A video processing assembly sends a phase video signal to the phase light modulation assembly based on the video signal. The phase light modulation assembly performs phase light modulation based on the phase video signal and the enable signal, in order to transmit a modulated light to the light modulator.