Backlight Module Threshold Voltage Drift Compensation
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Solution Overview
Problem
Current LED backlight modules experience uneven brightness due to threshold voltage drift in driving transistors, leading to differences in driving current and brightness across different LED devices.
Innovation Solution
A backlight module with a driving circuit that includes a data signal input module, a driving module, a detection module, and a storage module, which detects and compensates for threshold voltage drift by inputting a compensated data signal during the display stage, ensuring uniform light emission across backlight units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin film transistor driving circuit is used to drive LED devices, then the backlight module can be manufactured with standard processes, but threshold voltage drift occurs causing uneven brightness
Solution Approach 1:
The detection module measures the threshold voltage of the driving transistor before normal operation, and the storage module saves this threshold voltage value for subsequent compensation. This preliminary detection and storage action enables the system to compensate for threshold voltage drift during the display stage, ensuring uniform brightness across different LED devices while maintaining standard manufacturing processes.
2Manufacturing precision
If threshold voltage compensation is implemented, then brightness uniformity is improved, but circuit complexity increases
Solution Approach 1:
The detection module, storage module, and compensation function are integrated into the existing driving circuit structure. The detection module communicates with the control module, which already exists in the driving circuit, to input compensated data signals. This merging approach adds compensation functionality without significantly increasing overall circuit complexity.
Solution Approach 2:
The driving circuit performs self-diagnosis and self-compensation by detecting its own threshold voltage through the detection module and adjusting its operation through the storage module and control module. This self-service mechanism eliminates the need for external calibration equipment or complex external control systems.
3Reliability
If threshold voltage detection and compensation are added, then driving current uniformity is improved, but the number of circuit modules increases
Solution Approach 1:
The control module serves multiple functions: it receives detection signals from the detection module, processes the threshold voltage information, generates compensated data signals, and drives the LED devices. This multi-functionality reduces the need for separate dedicated modules for each function, thereby limiting the increase in the number of circuit modules while improving driving current consistency.
Data Source
AI summary
A backlight module and a display device are provided. The backlight module includes a backlight and a driving circuit for driving the backlight. In the driving circuit corresponding to at least one backlight unit in the backlight, a data signal input module is configured for inputting a first data signal to a first point during a detection stage, and inputting a compensated second data signal to the first point according to a threshold voltage detected by a detection module during a display stage. The present invention improves uniformity of light emission of the backlight module.