Segmented LED Backlight Circuit Synchronizes Signals to Remove Interference
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Solution Overview
Problem
Conventional segmented LED backlights experience intermodulation interference due to independent pulse-modulated signal control, leading to visible stripes on displays.
Innovation Solution
A circuit arrangement and method that synchronizes the modulated signal with the line and image frequencies of a display unit, using a generator to overlay synchronizing and data signals, thereby reducing intermodulation interference by ensuring the modulated signal follows the clock rate of the synchronizing signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If segmented LED backlights are controlled by independent pulse-modulated signals for each segment, then brightness control capability is improved, but intermodulation interference occurs causing visible stripes on display
Solution Approach 1:
The patent merges the control signals of multiple LED segments by overlaying them into a single composite signal. This composite signal is then distributed to all segments simultaneously, ensuring they are driven in unison at the same clock rate, thereby eliminating the intermodulation interference that arises from independent pulse-modulated control while preserving individual brightness control capability through signal modulation
2Adaptability or versatility
If each LED segment is driven by independently generated pulse-modulated signals, then individual segment brightness control is improved, but synchronization with display line frequency deteriorates causing interference patterns
Solution Approach 1:
The invention combines multiple independent segment control signals into a single synchronized composite signal that is locked to the display's line frequency. This merged signal maintains the adaptability for individual segment brightness control through its modulation components while ensuring all segments operate at the stable display clock rate, eliminating synchronization issues and interference patterns
3Productivity
If multiple independent control signals are generated for each LED segment, then brightness modulation capability is improved, but signal interference on display increases
Solution Approach 1:
The patent merges multiple brightness modulation signals into a single composite control signal that drives all LED segments simultaneously. This approach maintains the full brightness modulation capability for each segment through signal encoding while preventing the generation of intermodulation interference, as the segments are driven by a unified signal rather than multiple independent signals that would interact and create harmful interference patterns
Data Source
AI summary
A circuit arrangement for controlling a segmented LED backlight in particular, comprises a generator (50) with a first input (10) to be supplied with a synchronizing signal (SYNC) that comprises image frequency information and/or line frequency information of a display unit, a second input (20) to be supplied with a data signal (DATA) that comprises image information of the display unit, and with an output (30) for providing a modulated signal (MOD).