OLED Display Brightness Driving Method Voltage Switch Point Compensation
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Solution Overview
Problem
Current OLED display technologies experience sudden brightness variations due to the minimum voltage interval of 0.1V, leading to poor user experiences when adjusting display brightness, especially when switching between normal and high brightness modes.
Innovation Solution
An OLED display device and brightness driving method that utilize a data driving unit to output different data voltages based on whether the display brightness value corresponds to a voltage switch point, with a compensation data voltage generated to prevent brightness jumps between adjacent values, using a digital-analog converter and compensation data look-up table to fine-tune voltage adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the cathode voltage ELVSS is adjusted in voltage intervals of 0.1V to achieve brightness control, then the brightness can be adjusted between normal mode and high brightness mode, but the brightness has sudden large variation causing poor user experiences
Solution Approach 1:
The patent divides the brightness adjustment process into two independent control paths: one for normal mode brightness adjustment using data voltage, and another for high brightness mode switching using cathode voltage ELVSS. This segmentation allows each control path to operate with optimal step sizes, preventing sudden brightness jumps while maintaining the ability to achieve high brightness levels.
Solution Approach 2:
The patent changes the control parameter from direct cathode voltage adjustment to a hybrid approach where data voltage controls normal mode brightness and cathode voltage ELVSS controls high brightness mode switching. This parameter change enables finer granularity in brightness control during normal mode while still achieving the required high brightness levels when needed.
2Device complexity
If the power IC limits output to a minimum step of 0.1V, then the voltage control is simplified, but the corresponding brightness has large span causing sudden brightness variation
Solution Approach 1:
The patent introduces data voltage as an intermediary control parameter between the user interface and the OLED display. Instead of directly controlling brightness through cathode voltage ELVSS with large 0.1V steps, the data voltage acts as a mediator that provides fine-grained brightness adjustment in normal mode, while cathode voltage ELVSS serves as a secondary mediator for high brightness mode switching. This intermediary approach resolves the conflict between control simplicity and brightness variation span.
3Illumination intensity
If the cathode voltage ELVSS is increased to achieve high brightness mode, then the brightness approximating 1000 nit can be achieved, but the voltage difference between normal mode and HBM mode becomes greater causing brightness jump
Solution Approach 1:
The patent implements dynamic control strategy where the system automatically selects between two brightness control modes based on the current state. In normal mode, data voltage provides continuous fine-grained control for smooth transitions. When high brightness mode is detected, the system dynamically switches to cathode voltage ELVSS control with larger steps. This dynamic adaptation allows the system to maintain brightness transition stability while achieving the required high brightness capability of approximately 1000 nit.
Data Source
AI summary
An organic light emitting diode display device and a brightness driving method thereof are disclosed. The display device includes a display brightness value adjustment unit configured to adjust a display brightness value within a predetermined display brightness value interval and a data driving unit configured to receive a display brightness value and output different data voltages according to whether the display brightness value is equal to a display brightness value configured to correspond to a voltage switch point of a predetermined cathode voltage interval such that a brightness difference between any adjacent two of display brightness value is within a predetermined range.