Display Panel Driver Voltage Drop Compensation
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Solution Overview
Problem
Display devices experience luminance changes and unevenness due to voltage drops across data lines, as the data voltage generated by the data driver differs from the voltage applied to pixels based on their relative position in the display panel, leading to varying luminance across the display.
Innovation Solution
A display device with a display panel driver, timing controller, current path switch, voltage drop detector, and line resistance calculator that connects and disconnects pixels during voltage drop tests, calculates line resistances, and provides compensated data voltages to pixels based on these resistances to minimize luminance changes and unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If data voltage is transmitted through data lines to pixels, then pixels receive driving voltage for light emission, but voltage drops occur due to line resistance causing luminance changes and unevenness
Solution Approach 1:
The system performs preliminary measurement of line resistance during manufacturing or initialization, storing resistance values in a lookup table. During normal operation, the compensation controller retrieves pre-calculated compensated voltage values from this table based on the measured line resistance, avoiding real-time complex calculations and enabling rapid voltage compensation.
Solution Approach 2:
The system implements a feedback mechanism where the actual line resistance is measured and used to adjust the data voltage through compensation. The compensation controller continuously monitors line resistance and dynamically adjusts the voltage supplied to pixels based on the measured resistance values, ensuring luminance uniformity despite variations in line resistance.
2Illumination intensity
If line resistance is measured and compensation is applied to all pixels, then luminance uniformity is improved, but system complexity and measurement time increase
Solution Approach 1:
The display panel is divided into multiple regions, and line resistance measurement is performed selectively for each region rather than uniformly across the entire panel. The compensation controller applies region-specific compensation based on measured resistance values, reducing overall measurement complexity while maintaining luminance uniformity in each segmented area.
Solution Approach 2:
Instead of measuring line resistance for every single pixel, the system measures resistance at representative sampling points and uses these measurements to infer compensation values for surrounding pixels. This copying approach reduces the number of measurements required while still achieving effective compensation across the display panel.
3Illumination intensity
If real-time voltage compensation is calculated for each pixel, then luminance changes are minimized, but processing time and computational load increase
Solution Approach 1:
The system performs preliminary measurement of line resistance during manufacturing or initialization, storing resistance values in a lookup table. During normal operation, the compensation controller retrieves pre-calculated compensated voltage values from this table based on the measured line resistance, avoiding real-time complex calculations and enabling rapid voltage compensation.
Solution Approach 2:
The system performs line resistance measurement and compensation calibration periodically or at specific intervals rather than continuously for every frame. During normal display operation, the pre-established compensation values are used, reducing processing overhead while maintaining luminance consistency.
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 effectively reduces display luminance changes and unevenness by generating compensated data voltages based on detected line resistances, ensuring consistent luminance across the display panel.
Implementation Method 1
configured to apply a test voltage to the end of the first data line, and configured to measure a dropped test voltage at the end of the second data line
Implementation Method 2
a current path switch configured to connect a first pixel which is connected with a first data line to a second pixel which is connected with a second data line during a voltage drop test operation, and to separate the first pixel from the second pixel during an image display operation
Data Source
AI summary
A display device is disclosed. The device includes a display panel including a plurality of pixels including a first pixel electrically connected to a first data line and a second pixel electrically connected to a second data line. The display device also includes a current path switch configured to electrically connect the first pixel to the second pixel during a voltage drop test operation and electrically disconnect the first pixel from the second pixel during an image display operation. The display device further includes a voltage drop detector electrically connected to an end of the first data line and an end of the second data line, the voltage drop detector being configured to apply a test voltage to the end of the first data line and measure a dropped test voltage at the end of the second data line. The display device additionally includes a line resistance calculator.