Dummy Pixel Repair for OLED Outermost Line Defects
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Solution Overview
Problem
Organic light emitting display devices face challenges in repairing hot spot and dark spot errors, particularly on the outermost horizontal line, where no signals can be received from lower portions, limiting yield rates and increasing manufacturing costs due to the inability to fully repair these errors.
Innovation Solution
The use of dummy pixels under the affected pixels on the outermost line allows for signal sharing and error correction by welding and cutting specific connections to enable the dummy pixel circuit to operate and supply signals to the affected pixel areas, effectively repairing hot spot and dark spot errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dummy pixels are used to repair errors on the outermost line, then the yield rate increases and manufacturing costs reduce, but the device complexity increases due to additional dummy pixel structures and repair processes
Solution Approach 1:
Dummy pixels are pre-configured in the pixel array before final assembly, positioned at locations that can serve as signal sources for repair operations. These dummy pixels include complete pixel circuits (TFTs, capacitors, OLEDs) that are initially inactive but can be activated through laser welding to provide compensation signals to defective pixels on the outermost line.
Solution Approach 2:
The dummy pixels act as intermediary signal sources that mediate between the driving circuitry and defective pixels. By welding connections between dummy pixel circuits and defective pixel locations, the dummy pixels provide intermediate signal paths that enable repair of outermost line errors without requiring external compensation equipment.
2Reliability
If laser welding is used to connect dummy pixel circuits to affected pixels, then repair effectiveness improves, but the manufacturing process complexity increases
Solution Approach 1:
Traditional mechanical connection methods (wire bonding, conductive adhesive) are replaced with laser welding technology. The laser welding process uses focused laser beams to create precise electrical connections between dummy pixel circuits and defective pixel locations, providing superior connection reliability and precision while enabling automated repair processes.
Solution Approach 2:
The repair process utilizes controlled changes in laser parameters (power, pulse duration, focal position) to achieve reliable welding connections. By adjusting these parameters, the system can selectively weld different connection points (anode electrodes, cathode electrodes, or TFT terminals) to repair various types of pixel defects on the outermost line.
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 method increases the yield rate of organic light emitting display devices and reduces manufacturing costs by enabling the repair of errors on the outermost line, ensuring proper functionality and reducing the likelihood of production halts due to uncorrected errors.
Implementation Method 1
Each pixel of the display panel includes an organic light emitting diode OLED, which emits light with a data current Ioled applied thereto
Data Source
AI summary
An organic light emitting display device including a plurality of pixel areas including an emission area and a pixel circuit area, the plurality of pixel areas being configured to emit light; a plurality of dummy pixel areas formed adjacent to the plurality of pixel areas to include a non-emission area and a pixel circuit area; an anode electrode form in the plurality of dummy pixel areas; and a bridge line formed from a portion of the anode electrode and in the plurality of pixel areas.