Pixel Driving Circuit Compensation for Display Voltage Drop
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Solution Overview
Problem
Large-size display devices, such as LCDs, suffer from image quality issues due to longer data lines causing voltage drops, which result in inadequate charging of pixel electrodes, leading to deviations in data signals and poor image display.
Innovation Solution
A pixel cell with a pixel driving circuit comprising a switch module and a compensation module that stores and supplies a compensation voltage to counteract voltage drops along data lines, ensuring the pixel electrode receives a stable voltage, improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display device size is increased, then the display area is enlarged, but the data line length increases causing voltage drop and image quality deterioration
Solution Approach 1:
The pixel driving circuit is segmented into a compensation module and a switch module. The compensation module stores compensation voltage in a capacitor, while the switch module controls the timing of applying compensation voltage and data voltage to the pixel electrode. This segmentation allows independent optimization of voltage compensation and signal switching functions.
Solution Approach 2:
The compensation module performs preliminary action by storing the compensation voltage in advance during a first time period before the data signal is fully applied. This pre-stored compensation voltage is then added to the data voltage during the second time period, ensuring the pixel electrode receives adequate total voltage even when data line voltage has dropped due to length.
2Adaptability or versatility
If the data line length is increased to support larger displays, then the display capacity is improved, but the impedance increases causing greater voltage drop and signal deviation
Solution Approach 1:
The patent applies local quality by providing compensation specifically to pixels located far from the data driver where voltage drop is most severe. The compensation voltage is locally generated and stored in capacitors within each pixel's driving circuit, allowing targeted correction of voltage drop at distant locations without affecting the entire display uniformly.
Solution Approach 2:
The pixel driving circuit incorporates feedback through the compensation module that monitors and compensates for voltage drop. By storing compensation voltage based on the expected voltage loss and applying it in conjunction with the data voltage, the system creates a feedback mechanism that maintains reliable signal levels despite increased data line impedance.
3Use of energy by moving object
If the charging voltage of distant pixels is reduced due to voltage drop, then the power consumption is decreased, but the pixel electrode cannot be sufficiently charged leading to image quality deterioration
Solution Approach 1:
The patent changes the voltage parameter by adding compensation voltage to the data voltage. The compensation module stores a voltage value that compensates for the drop, and the switch module controls the timing to apply both compensation voltage and data voltage to the pixel electrode. This parameter change ensures sufficient charging voltage is achieved without increasing overall power consumption, as the compensation voltage is derived from the same data line through capacitive storage.
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 compensation module effectively compensates for voltage losses, ensuring the pixel electrode receives a voltage comparable to the sum of the compensation and data voltages, thereby enhancing the image display quality by maintaining consistent charging rates across the display device.
Implementation Method 1
the compensation module may comprise a first switch transistor, a second switch transistor and a capacitor
Data Source
AI summary
A pixel cell is disclosed including a pixel electrode and a pixel driving circuit. The pixel driving circuit includes a switch module and a compensation module. The compensation module is connected with a first signal line, a second signal line, a data line and the switch module. The switch module is connected with the second signal line, the compensation module and the pixel electrode. The compensation module is operable to store a compensation voltage under control of the first signal line and further to supply the compensation voltage and a data voltage supplied via the data line to the switch module under control of the second signal line. The switch module is operable to supply the compensation voltage and the data voltage to the pixel electrode under control of the second signal line.