News Column

Researchers Submit Patent Application, "Defect Inspection Device and Defect Inspection Method", for Approval

July 24, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventor Yanase, Masakazu (Osaka-shi, JP), filed on May 18, 2012, was made available online on July 10, 2014.

The patent's assignee is Sharp Kabushiki Kaisha.

News editors obtained the following quote from the background information supplied by the inventors: "A process for producing a liquid crystal panel includes, for example, an array (TFT) step, a cell (liquid crystal) step, and a module step. Among such steps, the array step includes the sub-steps of: (i) forming a gate electrode, a semiconductor film, a source/drain electrode, a protective film, and a transparent electrode on a transparent substrate; and (ii), after the sub-step (i), carrying out an array defect inspection to inspect the array for a defect such as a short circuit or a break existing in electrodes, wires, and the like.

"The array defect inspection is generally carried out by a method of bringing a probe into contact with an end part of a wire to measure an electrical resistance across the wire, an electrical resistance between adjacent wires, and an electrical capacitance between adjacent wires. However, although the array defect inspection by the above method can detect whether or not there exists a defect in a wire section, it has a difficulty in identifying a position of the defect.

"Examples of an inspection method for identifying the position of the defect encompass a visual inspection in which an operator observes a substrate under a microscope to identify the position of the defect. However, the visual inspection imposes a large burden on the operator and also has the problem of incorrectly identifying the position of the defect due to a difficulty in correctly detecting a defect. As such, there has been proposed an infrared inspection in which an image of the substrate taken with an infrared camera is subjected to image processing so that the position of the defect is identified.

"Patent Literature 1 relates to the infrared inspection, and discloses the following technique. That is, according to a thin-film transistor liquid crystal substrate of Patent Literature 1, a short circuit defect 803 is caused to generate heat by applying a voltage V between scanning lines 811 through 815 and signal lines 821 through 825 (see FIG. 9). Meanwhile, before and after the application of the voltage between the scanning lines 811 through 815 and the signal lines 821 through 825, image signals are detected along a broken line 806 under an infrared microscope. Next, a difference between the image signal thus detected before the application of the voltage and the image signal thus detected after the application of the voltage is obtained. Then, projections in respective X and Y directions are calculated. In this way, a pixel address of the short circuit defect 803 is identified."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventor's summary information for this patent application: "Technical Problem

"Patent Literature 1 uses an infrared microscope and therefore employs a configuration in which scanning is carried out along the broken line 806. However, Patent Literature 1 has the problem that the infrared inspection of a panel having a large area that needs to be inspected, like a large-sized liquid crystal panel, requires much time and thus reduces productivity.

"Therefore, an object of the present invention is to provide a defect inspection device and a method for inspecting a defect, each of which identifies a position of a short circuit defect in a short time, thereby achieving higher productivity than the conventional defect inspection device and the conventional defect inspection method.

"Solution to Problem

"In order to attain the object, a defect inspection device of the present invention for detecting a position of a defect existing in a wire formed on a panel, includes: a probe which applies a voltage to a terminal section of the wire; probe moving means for moving the probe to the terminal section; a first infrared sensor which photographs an entire surface of the panel; a second infrared sensor which photographs a part of the panel; and sensor moving means for moving the second infrared sensor to each position on the panel, the first infrared sensor including a plurality of infrared cameras.

"In order to attain the object, a method of the present invention for inspecting a defect existing in a wire formed in a panel, includes the steps of: (a) applying a voltage to a terminal section of the wire; (b) photographing, with a plurality of infrared cameras, an entire surface of the panel; and photographing, with one or more infrared cameras, a part of the panel.

"Advantageous Effects of Invention

"According to the present invention, it is possible to provide a defect inspection device and a method for inspecting a defect, each of which identifies a position of a short circuit defect in a short time, thereby achieving higher productivity than the conventional defect inspection device and the conventional defect inspection method.

BRIEF DESCRIPTION OF DRAWINGS

"FIG. 1 is a block diagram illustrating main components of a defect inspection device of an embodiment of the present invention.

"FIG. 2 is a perspective view illustrating the defect inspection device of the embodiment of the present invention.

"FIG. 3 is a perspective view illustrating configurations of a macrosensor and its surroundings.

"FIG. 4 is a plan view illustrating a visual field of an infrared camera when viewed from above the liquid crystal panel.

"FIG. 5 is a lateral view illustrating a visual field of the infrared camera which visual field is reflected on the liquid crystal panel.

"FIG. 6 is a plan view illustrating the liquid crystal panel and a probe.

"FIG. 7 is a view illustrating a flow of detecting a short circuit defect by an infrared inspection.

"FIG. 8 is a view schematically illustrating a defect existing in a pixel section.

"FIG. 9 is a view for explaining a method for identifying an address of a short circuit pixel of the conventional technique."

For additional information on this patent application, see: Yanase, Masakazu. Defect Inspection Device and Defect Inspection Method. Filed May 18, 2012 and posted July 10, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5138&p=103&f=G&l=50&d=PG01&S1=20140703.PD.&OS=PD/20140703&RS=PD/20140703

Keywords for this news article include: Sharp Kabushiki Kaisha.

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Source: Politics & Government Week


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