Backlight Control Circuit for 3D Display Signal Interference
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Solution Overview
Problem
In 3D mode electronic devices, the complex circuit and signal interference caused by multiple signal lines required for backlight control in LED modules, which complicates the process of scanning left-eye and right-eye images.
Innovation Solution
A backlight control circuit with a time schedule controller and LED driving unit that uses a single signal line to control the LED module, employing a backlight control pin to output specific voltage signals to manage LED emission during image scanning, ensuring synchronized control of LED strings without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple signal lines are used to control backlight for different picture portions in 3D mode, then the backlight can be controlled for each portion separately, but the circuit becomes complex and signal lines interfere with each other
Solution Approach 1:
The patent merges the control of multiple LED strings into a single signal line by combining multiple picture portions into one group. The controller outputs a single backlight control signal that simultaneously controls all LED strings in the group, eliminating the need for separate signal lines for each portion while maintaining the ability to control backlight timing for 3D mode operation.
Solution Approach 2:
The single backlight control signal line is designed to serve multiple functions: it controls backlight timing for both 2D and 3D modes, and can control multiple different picture portions by grouping them. This universal signal line replaces what would traditionally require multiple dedicated signal lines for different control scenarios.
2Manufacturing precision
If multiple signal lines are used to control backlight for different picture portions, then precise backlight timing control is achieved, but signal interference occurs between lines
Solution Approach 1:
By merging multiple signal lines into one, the patent eliminates signal interference between lines. The single backlight control signal line carries timing information that controls all LED strings simultaneously, removing the harmful electromagnetic interference that would occur between multiple adjacent signal lines operating in parallel.
3Illumination intensity
If the LED module remains on during the entire scanning time of left-eye or right-eye image, then continuous illumination is provided, but power consumption increases and image quality deteriorates
Solution Approach 1:
The patent implements periodic backlight control where the LED module is turned on and off in specific time intervals during the scanning of left-eye or right-eye images. The backlight is activated only during the scanning period of the current eye's image and turned off during the scanning period of the other eye's image, creating a periodic illumination pattern that reduces power consumption while maintaining perceived illumination through persistence of vision.
4Illumination intensity
If the LED module is turned on during scanning of left-eye or right-eye image, then illumination is provided, but ghosting or crosstalk occurs between left and right images
Solution Approach 1:
The backlight control signal is synchronized with the image scanning timing to create periodic illumination cycles. During left-eye image scanning, the backlight is turned on; during right-eye image scanning, the backlight is turned off. This periodic action ensures that each eye receives illumination only during its designated scanning period, preventing ghosting or crosstalk between left and right images while maintaining sufficient illumination intensity during active display periods.
Data Source
AI summary
A display panel driving method for driving a LED module of an electronic device to emit light, the method includes steps: controlling to scan a left-eye image and a right-eye image when the electronic device works at a 3D mode (S401); controlling the LED module to turn off and does not emits light during a predetermined period less than a scanning time of the left-eye image or the right-eye image, after switching to scan the left-eye image and the right-eye image (S402); and controlling the LED module to turn on and emit light after the predetermined period has passed (S403). The present invention also provides a backlight control circuit and an electronic device, the present invention capable of controlling the backlight module to emit light via the same signal and do not cause the interference between different signals.