Varied Reference Voltage for OLED Power Line Resistance
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Solution Overview
Problem
The increasing size of organic light-emitting display devices leads to power supply line resistance issues, causing variations in brightness across the display, which deteriorate picture quality due to the drop in power supply voltage from one end to the other.
Innovation Solution
An organic light-emitting display device with a power supplier that gradually varies the reference voltage along the distance from the power supplier, using a reference voltage generator, integrator, and switch controlled by synchronous signals to compensate for voltage decrement caused by power line resistance, ensuring uniform brightness across the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the power supply line is lengthened to support larger display devices, then the display size is increased, but the power supply voltage drops due to line resistance causing brightness variation
Solution Approach 1:
The patent applies local quality by making the reference voltage different at different locations along the power supply line. Instead of using a constant reference voltage, the system varies the reference voltage along the length of the power supply line to match the voltage drop characteristics, thereby compensating for resistance effects and maintaining uniform brightness across the entire display.
Solution Approach 2:
The patent changes the parameter of reference voltage from a constant value to a variable value that changes along the power supply line. The reference voltage is adjusted based on the position and corresponding voltage drop, transforming the system from a static voltage reference to a dynamic one that adapts to spatial variations in voltage delivery.
2Device complexity
If a constant reference voltage is used throughout the display, then the circuit design is simple, but brightness non-uniformity occurs due to power line resistance
Solution Approach 1:
The patent introduces dynamics into the reference voltage system by making it time-varying and position-dependent. The reference voltage is no longer a static constant but dynamically adjusts based on the scanning sequence and position along the power supply line, allowing the system to compensate for voltage drops in real-time during the scanning process.
Solution Approach 2:
The patent employs periodic action by varying the reference voltage in synchronization with the scanning sequence. As the scan progresses through different regions of the display, the reference voltage is periodically adjusted to match the voltage conditions at each location, creating a periodic variation that compensates for the periodic voltage drops along the power supply line.
Data Source
AI summary
An organic light emitting display device includes: an organic light emitting display panel configured to include a plurality of power lines, a plurality of scan lines and a plurality of data lines; a power supplier configured to apply a reference voltage to the power lines; and a controller configured to apply at least one control signal to the power supplier. The reference voltage is gradually varied along the distance from the power supplier.