Segmented Impulse Backlight for Stereoscopic 3D LCD Crosstalk
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Solution Overview
Problem
LCD monitors struggle to display stereoscopic 3D images effectively due to crosstalk and flicker issues caused by their 'sample and hold' display technique and slow frame rates, which are not comparable to the CRT's progressive raster scan and fast response time, limiting the quality of stereo 3D visualization.
Innovation Solution
A stereo 3D ready LCD monitor is developed using a high-frame-rate sample and hold display that employs a horizontally segmented impulse backlight and liquid crystal modulator to control image timing, eliminating crosstalk and maintaining brightness and contrast, while using circular polarized glasses for stereoscopic viewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If LCD monitors use sample and hold display technique, then image persistence is extended during complete frame display time, but crosstalk occurs between left and right eye images
Solution Approach 1:
The LCD panel is divided into two separate physical panels, each dedicated to displaying images for one eye. This spatial segmentation eliminates crosstalk by physically separating the left and right image display paths, while each panel maintains its own sample-and-hold operation independently.
Solution Approach 2:
A beam splitter is introduced as an intermediary optical element that directs light from the first LCD panel to the left eye and light from the second LCD panel to the right eye. This mediator prevents direct crosstalk between the panels while maintaining the benefits of sample-and-hold display.
2Loss of energy
If LCD monitors display at 60 frames per second, then power consumption is reduced compared to high frame rates, but significant flicker is perceived during stereo 3D viewing
Solution Approach 1:
The system employs periodic impulse backlighting that synchronizes with the stereo 3D frame sequence. By providing brief, intense illumination pulses timed to coincide with each frame display, the system maintains perceived brightness and eliminates flicker while allowing the LCD panels to operate at lower refresh rates for energy efficiency.
3Device complexity
If a single LCD panel is used for stereo 3D display, then device complexity is reduced, but crosstalk cannot be eliminated due to sequential line-by-line scanning
Solution Approach 1:
The display system is segmented into two independent LCD panels, each handling one eye's image stream. This physical division eliminates the crosstalk problem inherent in single-panel sequential scanning, as each panel operates independently without time-multiplexed content.
Solution Approach 2:
While using two panels increases display hardware, the system merges them through a beam splitter into a unified optical path that delivers separate stereoscopic images to each eye. This combination approach achieves crosstalk elimination while maintaining a compact integrated display structure.
4Speed
If LCD monitors use fast response time liquid crystal devices, then frame rate can be increased, but driving schemes typically limit frame rates to 60 fps
Solution Approach 1:
The system uses periodic impulse backlighting synchronized with high-frame-rate stereo 3D content display. This allows the LCD panels to refresh at higher rates (e.g., 120 Hz or above) by providing illumination only during active display intervals, eliminating the need for complex continuous driving schemes while achieving high frame rates.
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 enables high-quality stereoscopic 3D imaging with reduced flicker and crosstalk, achieving a better stereo 3D effect by synchronizing the impulse backlight and LC modulator with the display of left and right perspective views, outperforming traditional CRT-based systems in brightness and extinction ratio.
Implementation Method 1
a horizontally segmented liquid crystal modulator that performs the circular polarization
Implementation Method 2
The display switches between a left perspective view displayed with left handed circular polarization and a right perspective view displayed with right handed circular polarization
Implementation Method 3
A horizontally segmented impulse backlight is used to control the timing of the images displayed
Implementation Method 4
a horizontally segmented liquid crystal modulator that performs the circular polarization
Data Source
AI summary
A sample and hold display such as a Liquid Crystal Display (LCD) monitor that is capable of displaying video signals at a high frame rate, usually at over 120 frames per second, is described. The goal of the monitor is to enable the end user to view stereoscopic 3D images with the use of circular polarized glasses. The display switches between a left perspective view displayed with left handed circular polarization and a right perspective view displayed with right handed circular polarization as stereoscopic 3D images that are viewed with passive analyzing glasses. A horizontally segmented impulse backlight is used to control the timing of the images displayed in synchrony with a horizontally segmented liquid crystal modulator that performs the circular polarization. The impulse backlight and LC modulator eliminate crosstalk while maintaining brightness and high image contrast. Additionally, a unique driving scheme eliminates the appearance of individual segments.