OLED Luminance Uniformity Correction via Voltage Drop Compensation
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Solution Overview
Problem
High-resolution OLED display panels face non-uniform luminance issues due to voltage drops across supply lines, leading to inadequate charging of pixels and a degraded user experience.
Innovation Solution
A display panel system that calculates a luminance correction factor using image data and calibration constants to compensate drive signals, ensuring uniform luminance across the panel by adjusting the current or voltage provided to each pixel or supply line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel density is increased in larger displays, then resolution is improved, but voltage depletion across supply lines worsens causing non-uniform luminance
Solution Approach 1:
The patent applies local quality by dividing the display panel into multiple supply line groups and applying different compensation values to each group. The processor calculates a compensation value for each supply line based on its specific position and the total current of pixels connected to it, ensuring that each region receives appropriate compensation tailored to its local electrical characteristics rather than applying a uniform compensation across the entire panel.
Solution Approach 2:
The patent changes the drive signal parameters by adjusting the voltage or current supplied to each supply line based on calculated compensation values. The display driver modifies the drive signal characteristics (voltage level, current magnitude) for different supply lines to compensate for voltage drops, thereby maintaining uniform luminance across the display while supporting high pixel density.
2Speed
If current is transmitted rapidly over supply lines to charge pixels, then response speed is improved, but voltage depletion worsens leading to inadequate pixel charging
Solution Approach 1:
The patent applies preliminary action by calculating compensation values in advance based on the total current requirements of pixels connected to each supply line. The processor determines the compensation value for each supply line before the actual display refresh, using the sum of currents that will be drawn by the pixels. This pre-calculated compensation is then applied to the drive signal to prevent voltage depletion before it occurs during pixel charging.
Solution Approach 2:
The patent implements feedback by using the actual current consumption characteristics of pixels to determine compensation values. The system calculates compensation based on the total current of pixels connected to each supply line, creating a feedback loop where the drive signal is adjusted according to the actual electrical load and performance requirements of the display panel.
Data Source
AI summary
This application relates to systems, methods, and apparatus for reducing non-uniform luminance of an organic light emitting diode (OLED) display panel. In order to reduce non-uniform luminance, the display panel can compensate for an amount of voltage drop that is occurring across a line of the display panel. The voltage drop can be estimated based on image data provided to the display panel and one or more calibration constants stored by the display panel. The calibration constants can be generated during manufacturing of the display panel in order to equip the display panel with an accurate means for predicting voltage drop across each line of the display panel. During calibration, a predetermined display pattern is output by the display panel. Thereafter, an amount of luminance projected from the display panel is compared with an expected amount of luminance associated with the predetermined display pattern to calculate the calibration constant.