Pixel Circuit Time-Division Driving for Aperture Ratio
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Solution Overview
Problem
Conventional organic electroluminescent display devices have complex circuit structures and reduced yield due to the need for multiple transistors and signal lines per pixel, which complicates the arrangement of elements and reduces the aperture ratio and resolution.
Innovation Solution
A pixel circuit and driving method that simplifies the structure by using one driving element to time-divisionally drive red, green, and blue light emitting elements, reducing the number of emission control lines and transistors, and improving the aperture ratio and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple transistors and signal lines are used per pixel to drive red, green, and blue light emitting elements, then the display quality is improved, but the circuit structure becomes complex and yield is reduced
Solution Approach 1:
The patent merges the driving functions for red, green, and blue light emitting elements into a single driving transistor per pixel. Instead of using separate transistors for each color, one driving transistor sequentially controls all three color elements through time-division multiplexing, significantly simplifying the circuit structure while maintaining display quality.
Solution Approach 2:
The patent implements periodic action by sequentially driving red, green, and blue light emitting elements in time-division manner. The single driving transistor operates in periodic cycles, activating each color element in turn during different time intervals within a frame period, enabling color display through temporal multiplexing.
2Adaptability or versatility
If multiple transistors are arranged per pixel to drive each color element, then the display functionality is improved, but the aperture ratio is reduced
Solution Approach 1:
The patent combines multiple transistor functions into a single driving transistor, reducing the number of transistor elements that need to be arranged within each pixel. This merging approach frees up pixel area, increasing the aperture ratio while preserving the ability to drive all color elements through sequential operation.
Solution Approach 2:
The patent transitions from spatial arrangement of multiple transistors to temporal arrangement through time-division multiplexing. Instead of allocating separate spatial resources for each color element's driving transistor, the system uses the time dimension to sequence the driving operations, effectively adding a temporal dimension to the control mechanism.
3Measurement precision
If separate data lines are provided for each color element, then the control precision is improved, but the wiring complexity increases
Solution Approach 1:
The patent makes the single data line universal by enabling it to carry data signals for all three color elements (red, green, blue) sequentially. The data line performs multiple functions by time-division multiplexing, transmitting different color data at different time intervals, thereby eliminating the need for separate dedicated data lines for each color while maintaining precise control.
Solution Approach 2:
The data line operates under periodic action by sequentially transmitting data signals for red, green, and blue color elements in time-division manner. The data line is activated in periodic cycles, carrying different color data during different time windows, achieving precise control through temporal sequencing rather than spatial separation.
4Measurement precision
If multiple emission control lines are used to control each color element, then the emission control precision is improved, but the number of signal lines increases
Solution Approach 1:
The patent merges multiple emission control lines into a single emission control line that sequentially controls all color elements. Instead of having separate emission control lines for red, green, and blue elements, one control line performs all emission control functions by time-division multiplexing, reducing the total number of signal lines while maintaining precise emission control.
Solution Approach 2:
The single emission control line becomes universal by enabling it to control emission of all three color elements sequentially. The control line executes multiple control functions by activating different color elements at different time intervals, achieving precise emission control through temporal multiplexing rather than requiring separate dedicated control lines.
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
The solution simplifies the pixel circuit and wiring, reduces the number of elements and signal lines, and enhances the aperture ratio and yield, while also controlling white balance and brightness by adjusting the emission times of the light emitting elements.
Implementation Method 1
Red, green and blue organic emitting layers are respectively interposed between anode electrode and cathode electrode in each EL device so that light is emitted from the red, green and blue organic emitting layers by a voltage applied to the anode electrode and cathode electrode
Data Source
AI summary
A pixel circuit of display device for realizing a certain color during a display period of time comprising. The pixel circuit includes at least two light emitting elements, each said light emitting element for emitting a corresponding one of colors during the display period of time. An active element is commonly connected to the at least two light emitting elements to drive the at least two light emitting elements in response to at least one emission control signal. The active element time-divisionally drives the at least two light emitting elements using the at least one emission control signal during the display period of time per a sub display period of time. The at least two light emitting elements realize the certain color in the display period of time by time-divisionally emitting the corresponding ones of the colors, one of the corresponding ones of the colors being emitted per the sub display period of time.