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A METHOD OF DETECTING OPEN DEFECTS IN EXTENSION LINES

IP.com Disclosure Number: IPCOM000013343D
Original Publication Date: 2001-Oct-13
Included in the Prior Art Database: 2003-Jun-18
Document File: 8 page(s) / 121K

Publishing Venue

IBM

Abstract

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A METHOD OF DETECTING OPEN DEFECTS IN EXTENSION LINES

        Enter the body of your Invention Disclosure Publication below. You may include drawings and highlighting as appropriate.

1. Introduction

Nowadays, FPD panels enlarge and consist of fine pixels, so that the time for driving each line tends to be shortened. For this reason, to avoid transient distortion, it is expected that the products driven from both sides increase. However, taking care of costs and time for testing, the voltage is driven only from a single side at array test. Under this condition, there could be misjudgment about open defects that happen on the other and invisible area of driving side. It is not enough for the line, which has this type of defect, to drive voltage only from a single side at the final state of product. How to detect them is described here.

2. Current version of open test

2.1. How to detect As for general FPD, signal and gate lines are crossing and the pixels are located on that point. In this part, there are stray capacitance as shown in Fig.1. To check open defect, all of the pixels are scanned and these data are retrieved. As an example for the open test on gate lines, it is described as follows.

1) Pick up 8 pixels on farthest un-driving side and refer their charge data every gate line.
2) If there are 7 or more pixels have no (almost zero) charge data, then this line is judged as open defect.
3) And the disconnected point is searched.

In addition, it is also applicable to signal lines.

2.2. Coverage of detection Supposing both-sides drive system on signal and gate sides for an example, open defects, which are detectable or undetectable by applying the present method, are shown in Fig.2. That is, it can say that it's impossible for the present method to detect open defects that generated outside the FPD display domain on the other side of driving side.

2. Developed version of open test

3.1. Target The target is the open defect which was described previously and which cannot be detected now. It is shown in Fig.3.

3.2. How to detect At first, adding the following systems to the test equipment.

1) Probing to the all of pads on the other side of driving voltage, terminate them by the commercial capacitor as shown in Fig.4.
2) Short all of terminated points and connect to the unused channel on the opposite function of test unit.

In this state, the usual open test is done first. The following performs only the lines that have no

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open defect.

3) Scan additional capacitor.
4) Judge as "open defect in invisible area", if it doesn't have enough charge data.

3.3. The actual result Using an inorganic EL (a kind of FPD) panel that has 64 x 248 pixels, it was performed to detect open defect in invisible area as shown in Fig.5. It can be confirmed

    - There is no bad point with gate scanning on the pixels in visible area. - There is a bad point with dat...