Pixel Driving Circuit Time Interval Control for Mini LED Brightness
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Solution Overview
Problem
The 4T1C driving circuit used in Mini LED direct display screens reduces brightness compared to 3T1C circuits under the same current conditions, necessitating increased transistor size to maintain brightness, which complicates design and reduces display performance.
Innovation Solution
The proposed display panel incorporates pixel driving circuits with a light-emitting element, driving transistor, data writing transistor, and reset transistor, utilizing a hybrid driving method that adjusts time intervals between scanning signals to control the light-emitting loop, switching between pulse width modulation and pulse amplitude modulation modes for odd and even subframes to optimize grayscale display without increasing transistor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 4T1C driving circuit is used in PHM mode, then the display panel can achieve grayscale control through separate PAM and PWM subframes, but the brightness is reduced under the same current compared to 3T1C circuits
Solution Approach 1:
The patent changes the time interval parameter between the effective level of the first scanning signal and the effective level of the second scanning signal in the second subframe. By adjusting this time interval, the conduction duration of the light-emitting loop is controlled, which compensates for the brightness reduction caused by the 4T1C circuit structure while maintaining grayscale control capability through PHM mode.
2Illumination intensity
If transistor size is increased to maintain brightness in 4T1C circuits, then display brightness can be maintained, but design complexity increases and display performance decreases
Solution Approach 1:
Instead of increasing transistor size, the patent changes the time interval parameter of the scanning signals. This parameter adjustment allows brightness control without modifying the physical size of transistors, thereby avoiding increased design complexity and maintaining display performance while achieving the desired brightness level.
Data Source
AI summary
Display panels and driving methods thereof are provided. The driving method includes: obtaining to-be-displayed grayscales of a frame of to-be-displayed image, where the frame of to-be-displayed image includes at least one first subframe and at least one second subframe; determining a target driving mode of each pixel driving circuit according to the to-be-displayed grayscales, where the target driving mode includes a first driving mode and a second driving mode; and when the target driving mode is the first driving mode, adjusting a time interval between an effective level of a first scanning signal and an effective level of a second scanning signal in the second subframe, so as to control a conduction duration of a light-emitting loop, where the first scanning signal includes at least one effective level in both the first and second subframes, and the second scanning signal includes the effective level between the first and second subframes.