Scanning Drive Circuit Area Reduction for OLED Frame Narrowing
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Solution Overview
Problem
The existing configuration of organic electroluminescent (EL) display devices with pixel circuits consisting of one organic EL element, six N-channel thin film transistors, and one holding capacitor requires a large area for the scanning-side drive circuit, making it challenging to achieve frame narrowing, especially in mobile devices like smartphones.
Innovation Solution
The display device incorporates a scanning-side drive circuit with a shift register configuration that selectively drives multiple scanning signal lines and light emission control lines, where each unit circuit in the shift register corresponds to fewer lines, allowing for efficient driving of Q lines at a time, reducing the circuit area required around the display portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a scanning-side drive circuit with separate drive circuits for each scanning signal line and light emission control line is used, then the display performance is maintained, but the circuit area becomes large making frame narrowing difficult
Solution Approach 1:
The patent merges multiple separate drive circuits (first scanning signal line drive circuit, second scanning signal line drive circuit, first light emission control line drive circuit, second light emission control line drive circuit) into a single integrated scanning-side drive circuit. This integration reduces the overall circuit area while maintaining the functional capability to drive multiple scanning signal lines and light emission control lines, thereby enabling frame narrowing in mobile devices.
2Reliability
If multiple separate drive circuits are provided for scanning signal lines and light emission control lines, then effective display performance is maintained, but the device complexity increases
Solution Approach 1:
The patent combines four separate drive circuits into one unified scanning-side drive circuit that can selectively drive multiple scanning signal lines and light emission control lines. This reduces device complexity by eliminating redundant circuit structures while maintaining the reliability of display performance through coordinated control of all signal lines within the integrated circuit.
Solution Approach 2:
The integrated scanning-side drive circuit is designed to perform multiple functions: driving first scanning signal lines, second scanning signal lines, first light emission control lines, and second light emission control lines. This multi-functional design reduces the need for separate dedicated circuits for each function, thereby simplifying the overall device structure while maintaining effective display performance.
Data Source
AI summary
To realize frame narrowing of a display device that uses a display element driven by a current. A second scanning signal line drive circuit configured to drive second scanning signal lines each connected to a control terminal of a writing control transistor is constituted by a shift register composed of unit circuits equal in number to half a number of the second scanning signal lines. Each of the unit circuits included in the shift register collectively drives two of the second scanning signal lines adjacent to each other. In a period during which a power supply control transistor and a light emission control transistor are maintained in an off state and the writing control transistor is maintained in an on state in first and second pixel circuits connected to the two second scanning signal lines adjacent to each other, a threshold voltage compensation transistor and an initialization transistor in the first pixel circuit and a threshold voltage compensation transistor and an initialization transistor in the second pixel circuit are sequentially set to an on state for a predetermined period each.