Light Emitting Display Apparatus Transistor Degradation Compensation
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Solution Overview
Problem
In light emitting display apparatuses, the degradation of a driving transistor leads to a shift in data voltage, causing defects like a widthwise belt and color sense differences in the displayed image due to insufficient supply of normal data voltage to the pixel driving unit during compensation operations.
Innovation Solution
A light emitting display apparatus that turns on a transistor connected to the data line during the data period when a data voltage is supplied, using a gate driver to control the transistor's on/off states, ensuring proper data voltage delivery to the pixel driving unit through a switching driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compensation operation is performed by turning on a transistor in the pixel driving unit during compensation period, then transistor degradation compensation is achieved, but data voltage is shifted through coupling to the transistor causing widthwise belt defects and color sense differences
Solution Approach 1:
The patent divides the data period into multiple sub-periods: a first data period for normal data voltage supply, a second data period for compensation operation, and a third data period for recovery. This temporal segmentation allows the transistor to be selectively activated only during the compensation phase while remaining off during normal data voltage supply, thus preventing coupling-induced voltage shifts and display defects while still achieving transistor degradation compensation.
Solution Approach 2:
The patent performs compensation operations during a dedicated second data period that is inserted between the first and third data periods. By scheduling the compensation operation in advance during a specific time window when the pixel is not actively displaying, the system prepares the transistor's state beforehand to avoid degradation effects without interfering with normal data voltage supply to the display circuit.
2Reliability
If a transistor is turned on during compensation operation, then compensation is achieved, but normal data voltage cannot be supplied to the pixel driving unit
Solution Approach 1:
The patent segments the data period into distinct phases where the transistor is activated only during the second data period for compensation operations. During the first and third data periods, the transistor remains off to ensure uninterrupted normal data voltage supply. This temporal division allows both compensation and normal data supply to occur without conflict, maintaining productivity while achieving reliability improvements.
Solution Approach 2:
The patent implements periodic compensation operations within the data period structure, where the transistor is turned on and off in a regular pattern corresponding to the second data period. This periodic activation ensures that compensation is performed at appropriate intervals without continuously blocking the data voltage supply path, thus maintaining both compensation effectiveness and data supply efficiency.
Data Source
AI summary
A light emitting display apparatus, which turns on a first transistor included in a pixel driving unit and connected to a data line during a data period where a data voltage is supplied from a data driver to the data line, is provided. The light emitting display apparatus includes a light emitting display panel including a pixel including a first transistor connected to a gate line and a data line, a gate driver supplying a gate signal to the first transistor, a data driver supplying a data voltage to the data line, and a switching driver connecting the data line to the data driver or connecting a sensing line to the data driver, wherein the gate driver turns on and then turns off the first transistor during a data period where a data voltage is supplied from the data driver to the data line through the switching driver.