OLED Cell Driver Circuit Eliminates Initialization Voltage Line
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Solution Overview
Problem
Existing OLED display devices face limitations in aperture ratio and bezel region size due to the need for initialization voltage supply lines and additional circuit components, which hinder brightness and efficiency.
Innovation Solution
The OLED display device and driving method eliminate the initialization voltage supply line by using a cell driver with specific switch elements and capacitors to apply and manage voltages, enhancing aperture ratio and reducing bezel size by simplifying the circuit configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an initialization voltage supply line is added to apply reference voltage to the anode electrode, then the OLED can be properly initialized, but the aperture ratio is reduced and the bezel region size increases
Solution Approach 1:
The patent merges the initialization voltage supply function into the existing gate line structure. The gate line is used both for scanning control and for supplying initialization voltage to the anode electrode, eliminating the need for a separate initialization voltage supply line. This integration maintains the initialization function while freeing up pixel area and reducing bezel region size.
Solution Approach 2:
The gate line is given multiple functions: it serves as both the scanning signal transmission line and the initialization voltage supply line. By making the gate line universal, the patent eliminates redundant circuit components and increases the aperture ratio without compromising the initialization capability of the OLED.
2Reliability
If additional circuit components are added to manage initialization voltage, then proper voltage control is achieved, but the bezel region size increases
Solution Approach 1:
The patent combines the voltage control function into the existing cell driver circuitry. The cell driver that already controls the OLED operation is also used to manage the initialization voltage timing and level, eliminating the need for separate voltage control components and reducing bezel region size.
Solution Approach 2:
The cell driver circuit automatically manages the initialization voltage supply without requiring external control components. The circuit uses its own internal control logic to timing the initialization voltage application, making the system self-sufficient and reducing external component requirements.
3Illumination intensity
If the aperture ratio is increased by removing initialization voltage supply lines, then brightness and efficiency improve, but the initialization function must be maintained
Solution Approach 1:
The initialization function is merged into the gate line operation. The gate line is timed to supply initialization voltage to the anode electrode during the appropriate interval before data writing, ensuring proper OLED initialization while maintaining the increased aperture ratio achieved by removing separate supply lines.
Solution Approach 2:
The initialization voltage is applied in advance during the initialization interval before the data voltage is written to the pixel. This preliminary action ensures the OLED is properly initialized and ready to receive data, maintaining reliability while allowing the aperture ratio to be maximized.
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 improves the aperture ratio of the organic emission layer and minimizes the bezel region, leading to increased brightness and reduced size, while compensating for TFT deviations and voltage drops, thus enhancing overall display performance.
Implementation Method 1
The OLED includes an anode electrode, a cathode electrode and an organic emission layer interposed between the anode and cathode electrodes
Data Source
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AI summary
Provided is an OLED display device including a plurality of pixel each of which includes a light emitting element and a cell driver configured to drive the light emitting element. The cell driver includes: a driving switch element serially connected with the light emitting element between a high voltage supply line and a low voltage supply line; a first switch element configured to, in response to a second scan signal, connect a data line with a first node to which a gate electrode of the driving switch element is connected; a second switch element configured to, in response to a first scan signal, apply a third scan signal to a second node to which a source electrode of the driving switch element is connected; and a third switch element configured to, in response to an emission signal, connect the high voltage supply line with a drain electrode of the driving switch element.