OLED Digital Driving Method Using Mixed Sub-Frame Timing
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Solution Overview
Problem
Conventional digital driving methods for OLED display devices face challenges in reducing hardware specifications and achieving high luminance, with existing methods either requiring high hardware demands or resulting in low overall luminance due to inefficient sub-frame timing.
Innovation Solution
A digital driving method that utilizes a 3T1C pixel driving circuit with a combination of unequal-length and equal-length sub-frames, adjusting the time gap between charging and discharging TFTs to control illuminating times, reducing hardware requirements while improving luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If unequal sub-frame digital driving method is used, then luminance control precision is improved, but hardware specification requirements increase significantly
Solution Approach 1:
The frame is divided into multiple sub-frames with different luminance weights (1:1/2:1/4:1/8:1/16:1/32:1/64:1/128), allowing grayscale representation through temporal integration. This segmentation enables precise luminance control by varying the duration of each sub-frame while maintaining backward compatibility with existing OLED hardware
Solution Approach 2:
The patent employs periodic sub-frame scanning where each frame is divided into multiple sub-frames that are sequentially displayed. By controlling the illuminating time of each sub-frame according to specific time weights, the method achieves PWM-like luminance control without requiring high-speed hardware switching, thus reducing hardware specification demands
2Device complexity
If equal sub-frame digital driving method is used, then hardware specification requirements are reduced, but overall luminance decreases significantly
Solution Approach 1:
The patent dynamically adjusts the illuminating time of each sub-frame based on its assigned time weight. Instead of using fixed equal-duration sub-frames, the method varies the duration of each sub-frame (e.g., 1:1/2:1/4 ratio) to optimize both luminance output and hardware requirements. This dynamic timing adjustment allows the pixel to illuminate for longer periods while still achieving precise grayscale control
Solution Approach 2:
The patent changes the temporal parameters of sub-frames by assigning different time weights and durations to each sub-frame. By modifying the illuminating time parameter dynamically across sub-frames (rather than using equal durations), the method achieves both reduced hardware requirements and improved overall luminance through optimized temporal integration
3Duration of action of stationary object
If analog driving method is used, then display continuity is maintained, but threshold voltage drift causes uneven luminance
Solution Approach 1:
The patent replaces the analog voltage-based driving system with a digital pulse-width modulation system. Instead of continuously varying the gate voltage (analog method), the method uses discrete digital voltage levels (GM1 and GM9) combined with variable sub-frame durations to control luminance. This substitution eliminates threshold voltage drift issues while maintaining display continuity through temporal integration of multiple sub-frames
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
This approach effectively reduces hardware specifications, enhances luminance, and ensures display quality by optimizing sub-frame timing, achieving a significant reduction in frame rate requirements and increasing pixel illuminating time compared to prior methods.
Implementation Method 1
The organic light emitting diode (OLED) display panel provides the advantages of active light-emitting
Data Source
AI summary
The invention provides a digital driving method for OLED display device, by using a 3T1C pixel driving circuit comprising a first TFT, a second TFT, a third TFT, a capacitor, and an OLED to drive each sub-pixel, and by dividing a frame of OLED display device into a plurality of unequal-length sub-frames and equal-length sub-frames, and by changing the time gap between the first TFT charging and the third TFT discharging to control the illuminating time of each equal-length sub-frame. By combining the unequal-length and equal-length sub-frames, compared to the unequal-length sub-frame driving only in prior arts, the method can effectively reduce required hardware specification, improve luminance of OLED display device, and ensure the display quality of the OLED display device.