Backlight Unit Frame Transition Control for 3D Display Crosstalk
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Solution Overview
Problem
Frame-sequential 3D display systems face issues with crosstalk between left and right frames due to the inability to instantaneously replace frames, leading to narrow duty cycles and reduced image brightness, especially as frame rates increase.
Innovation Solution
Implementing 3D backlight units (BLUs) that control illumination to allow full pixel values for each frame without overlap, ensuring that a viewer sees only one frame at a time by turning off BLUs during frame transitions and turning them on only when the complete set of pixel values for a frame has been outputted, thereby eliminating crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If duty cycles of shuttered glasses are significantly reduced and tightly controlled to give the viewer a narrow temporal window during which the viewer may see a frame of a pure perspective, then crosstalk between frames is reduced, but the user perceives relatively dim images and most of the backlight is wasted
Solution Approach 1:
The backlight unit is turned off before the frame transition is complete, during the period when pixel values are being replaced. This preliminary action prevents crosstalk by ensuring the backlight is not illuminating partial frames from both perspectives, while still allowing the shuttered glasses to have sufficient duty cycle for the viewer to perceive bright images.
2Productivity
If frame rates of display systems are increased to 240 Hz and above, then the display system can present more frames per second, but the temporal window for viewing pure perspective frames becomes narrower and crosstalk problems are exacerbated
Solution Approach 1:
The backlight unit is turned off in advance during the frame transition period, before the new frame is fully displayed. This preliminary action is critical at high frame rates like 240 Hz, where the transition time is very short, to prevent crosstalk while maintaining adequate duty cycle for the shuttered glasses.
Solution Approach 2:
The system rapidly transitions between frames at high frame rates (240 Hz and above), and the backlight unit is synchronized to turn off during these rapid transitions. This rushing through of frame transitions with coordinated backlight control eliminates crosstalk even at the very narrow temporal windows created by high frame rates.
3Object-generated harmful factors
If the temporal window is narrow to synchronize shuttered glasses with frame playing, then crosstalk is minimized, but most of the backlight is wasted when the viewer is blocked from seeing any frame
Solution Approach 1:
The backlight unit is turned off before the frame transition is complete, during the period when pixel values are being replaced. This preliminary action prevents crosstalk by ensuring the backlight is not illuminating partial frames from both perspectives, while still allowing the shuttered glasses to have sufficient duty cycle for the viewer to perceive bright images.
Data Source
AI summary
Techniques for 3D back light units are described. In some possible embodiments, in a first time interval during which one or more back light units of a display system are turned off, a complete set of left pixel values in a left frame is outputted to a display panel of the display system. In some possible embodiments, in a second time interval during which the complete set of left pixel values in the left frame has been outputted to the display panel of the display system, the one or more back light units are turned on to illuminate the display panel and the second time interval is subsequent to, and is not overlapped with, the first time interval.