OLED Pixel Unit Time-Division Driving Circuit
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Solution Overview
Problem
Existing OLED display devices require a large number of driving modules and transistors, leading to increased area occupation and reduced pixel density due to each pixel unit having multiple driving modules that emit light simultaneously.
Innovation Solution
The OLED pixel unit incorporates a reduced number of driving modules, with each module generating a driving current to drive multiple light-emitting units across multiple frames, utilizing a selecting module to gate the light-emitting units and thin film transistors to control the light emission, allowing full color display with fewer driving modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each subpixel is driven by an individual driving module to emit light simultaneously, then the display quality is maintained, but the number of driving modules increases, resulting in larger area occupation and reduced pixel density
Solution Approach 1:
Multiple light emitting units (subpixels) are driven by a shared driving module through time-division multiplexing. The driving module sequentially drives different light emitting units in different frames, merging the driving function for multiple subpixels into a single module, thereby reducing the total number of driving modules and the area they occupy.
Solution Approach 2:
The light emitting units are driven in a periodic time-division manner where each light emitting unit is activated in alternating frames. For example, in even frames one subpixel is driven while in odd frames another subpixel is driven, creating a periodic driving pattern that allows shared use of the driving module across multiple subpixels.
2Area of stationary object
If the number of driving modules is reduced, then the area occupied by pixel unit decreases and pixel density improves, but the complexity of driving control increases
Solution Approach 1:
The selecting module dynamically switches the connection between the driving module and different light emitting units based on the frame number. The switching transistor changes its conduction state periodically, connecting the driving module to different subpixels in different frames, thereby enabling flexible time-division multiplexing control.
Solution Approach 2:
A selecting module comprising switching transistors is introduced as an intermediary between the driving module and the light emitting units. This intermediary dynamically routes the driving current from the shared driving module to the appropriate light emitting unit in each frame, managing the complexity of controlling multiple subpixels with a single driving module.
3Device complexity
If light emitting units are driven in different frames, then fewer driving modules are needed, but the time interval between light emission must be controlled within human visual persistence time to avoid visible flicker
Solution Approach 1:
The driving module operates in a periodic time-division manner, sequentially driving different light emitting units in alternating frames. This periodic driving ensures that each light emitting unit is activated at regular intervals, and by controlling the frame rate and switching timing, the overall refresh rate remains within the human visual persistence threshold to prevent visible flicker.
Solution Approach 2:
While individual light emitting units are activated discontinuously in alternating frames, the overall display system maintains continuous useful action through rapid alternation. The human visual system integrates the alternating light emissions from different subpixels, perceiving a continuous and stable image when the switching frequency exceeds the visual persistence threshold.
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 configuration reduces the area occupied by each pixel unit, enhancing pixel density by allowing the OLED display device to display one pixel across multiple frames, thereby increasing refresh rates and improving display efficiency.
Implementation Method 1
a first electrode and a second electrode of the thin film transistor are connected with the driving module and the light emitting unit, respectively
Data Source
AI summary
An OLED pixel unit, a method of driving the same and an OLED display device are provided. The OLED pixel unit comprises M driving modules, a light emitting module comprising N light emitting units and a selecting module for performing gating so that the light emitting unit about to emit light in each frame of picture is connected with the corresponding driving module, wherein M<N. The N light emitting units emit N colors of light. Each driving module generates at most one driving current in a frame of picture to drive one light emitting unit to emit light, and at least one driving module generates the driving current in each of frames of pictures to drive different light emitting units to emit light in the frames of pictures, so that the M driving modules drive the N light emitting units to emit light in n frames of pictures, wherein 2≦n≦N.