Display Device Restoration Strip Conductor for Luminescent Defect Repair
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Solution Overview
Problem
Conventional methods fail to effectively restore luminescent-point defects in liquid crystal display devices using liquid crystals with high gradation properties, as applying gate line voltage results in voltage exceeding predetermined values, leading to halftone gradation rather than dark-point defects.
Innovation Solution
A display device with a restoration strip conductor formed of a semiconductor film connected to the scanning line and extending to cover the edge of the pixel electrode, allowing for controlled voltage application through a high-resistance path, and laser-induced short-circuiting to correct defects, including those caused by short-circuits between source and drain electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate line voltage is directly applied to a pixel, then the voltage to be applied to the liquid crystal exceeds the predetermined value, but the luminescent-point defect is not turned to a dark-point defect, instead turned to a luminescent-point defect having a halftone gradation
Solution Approach 1:
A restoration strip conductor is introduced as an intermediary component between the gate line and the pixel electrode. This conductor includes a semiconductor film formed on the gate line with a resistance value higher than that of the gate line, serving as a current-limiting resistor. When the gate line voltage is applied, the restoration strip conductor limits the voltage to a predetermined value or less, preventing the formation of halftone gradation defects and enabling effective conversion of luminescent-point defects to dark-point defects.
2Ease of repair
If a laser beam is irradiated to create a short-circuit between drain electrode and gate wiring, then the luminescent-point defect is turned to a dark-point defect, but the method is ineffective for liquid crystals with high gradation properties where voltage exceeds predetermined values
Solution Approach 1:
The restoration strip conductor is formed during the manufacturing process before defects occur, serving as a preventive measure. By pre-installing the current-limiting resistor function in the circuit, the system is prepared to handle voltage limiting requirements for future defect restoration operations, making the laser-induced short-circuit method effective for both conventional and high gradation liquid crystal types.
3Illumination intensity
If the voltage to be applied to the liquid crystal is increased, then the gradation is high, but the luminescent-point defect cannot be effectively restored
Solution Approach 1:
The restoration strip conductor is selectively applied only to pixels that require defect restoration, while leaving other pixels with normal switching devices unaffected. This localized approach allows high voltage to be applied to specific defective pixels through the current-limiting restoration strip conductor, enabling defect restoration without compromising the overall display quality and gradation performance of the display device.
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
Enables restoration of luminescent-point defects to dark points, even when the applied voltage exceeds predetermined values, thereby improving display performance and fabrication yield by suppressing halftone gradation and securely restoring defects.
Implementation Method 1
a semiconductor film and a restoration conductor composed of a semiconductor film that are formed, with an insulating film intervening, on the gate electrode and on a portion, of the scanning line, that is apart from the gate electrode, respectively
Implementation Method 2
by irradiating a laser beam onto a portion, corresponding to a pixel having a luminescent-point defect, where the drain electrode and the gate wiring overlap each other and creating a short-circuit between the drain electrode and the gate wiring
Data Source
AI summary
Provision is made for a defect to be restored, by securely turning a luminescent-point defect of a display device to a dark point. In a display device including a scanning line (1), a video signal line (4) intersecting with the scanning line, a semiconductor film (3) and a restoration conductor (10) composed a semiconductor film that are formed, with an insulating film intervening, on a gate electrode (2) and on a portion, of the scanning line, that is apart from the gate electrode, respectively, a source electrode (5) that is formed on the semiconductor film and connected to the video signal line, a drain electrode (6) formed, opposing the source electrode, on the semiconductor film, a pixel electrode (9) connected to the drain electrode, and an extended portion (7) that is connected to the drain electrode and formed so as to cover an edge portion, of the pixel electrode, that is in the vicinity of the scanning line, the restoration strip conductor is connected to the extended portion.