OLED Drive Voltage Circuit for Accurate Deterioration Sensing
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) in display devices deteriorate over time, leading to decreased luminance and image quality due to uneven degradation across subpixels, which existing technologies fail to accurately sense and compensate for.
Innovation Solution
A display device with a drive voltage supply circuit that senses OLED deterioration by measuring variations in electric charge during a dedicated deterioration sensing period using a lower drive voltage, allowing for accurate compensation and preventing damage to the drive voltage supply circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a high drive voltage is supplied to the display panel during display driving, then the luminance and brightness of the OLED are improved, but the risk of damage to the drive voltage supply circuit increases during deterioration sensing
Solution Approach 1:
The drive voltage supply circuit operates in periodic cycles, alternating between a display driving period where high first drive voltage is supplied for normal operation and a deterioration sensing period where low second drive voltage is supplied for sensing. This periodic switching resolves the contradiction by separating the high-voltage operation from the sensing operation, preventing circuit damage while maintaining luminance during display driving.
Solution Approach 2:
The drive voltage supply circuit dynamically adjusts the drive voltage level based on the operational phase. During the display driving period, the circuit supplies high first drive voltage to maintain luminance. During the deterioration sensing period, it switches to low second drive voltage to prevent damage. This dynamic voltage adjustment allows the system to optimize both luminance performance and circuit safety at different times.
2Measurement precision
If a low drive voltage is supplied during deterioration sensing, then the accuracy of OLED deterioration sensing is improved, but the luminance and display quality deteriorate
Solution Approach 1:
The system implements periodic operation with distinct display driving periods and deterioration sensing periods. During display driving periods, high first drive voltage is supplied to maintain normal luminance and display quality. During dedicated deterioration sensing periods, low second drive voltage is supplied to enable accurate sensing. This temporal separation allows the system to achieve both high luminance during display and high sensing accuracy during sensing without compromising either function.
3Productivity
If the drive voltage is not discharged between operating periods, then the continuity of display operation is improved, but the accuracy of deterioration sensing decreases due to residual voltage interference
Solution Approach 1:
The drive voltage supply circuit performs preliminary discharge of residual first drive voltage during the transition period before the deterioration sensing period begins. This preliminary action removes voltage interference that would otherwise compromise sensing accuracy. After discharge is complete, the circuit then supplies the second drive voltage for accurate deterioration sensing, ensuring both display continuity and sensing precision.
4Measurement precision
If a dedicated deterioration sensing period is introduced, then the accuracy of OLED deterioration detection is improved, but the overall productivity and display time are reduced
Solution Approach 1:
The system implements periodic operation where deterioration sensing is performed in dedicated periods interspersed with normal display driving periods. The controller manages this periodic switching, allocating specific time intervals for sensing while maintaining the majority of time for display operation. This approach achieves accurate deterioration detection without significantly compromising overall productivity, as sensing is performed efficiently during designated intervals.
Data Source
AI summary
A drive voltage supply circuit, a display panel, and a display device are provided. By supplying a drive voltage lower than a drive voltage for display driving in a period in which sensing deterioration of an organic light emitting diode disposed in each sub pixel, an operating voltage of the organic light emitting diode is kept constant and a degree of deterioration of the organic light emitting diode can be accurately sensed. By discharging the drive voltage supplied to the display panel and controlling a current flowing in the process of discharge before supplying the drive voltage for deterioration sensing, drive voltages of different levels can be stably supplied in a display driving period and a deterioration sensing period.