LCD device including a TFT for reducing leakage current
DC CAFC
First Claim
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1. A liquid crystal display (LCD) device comprising a TFT (thin-film-transistor) substrate mounting thereon a plurality of TFTs each having a channel in an ohmic contact layer and a semiconductor layer;
- a counter substrate mounting thereon a black matrix;
a liquid crystal layer sandwiched between said TFT substrate and said counter substrate;
a backlight unit disposed at a rear side of said TFT substrate for irradiating said TFT substrate with backlight, said counter substrate mounting thereon a light shield overlapping said channel of said TFTs as view normal to said counter substrate; and
a rear shield film interposed between said channel of said TFTs and said backlight unit to overlap said channel of said TFTs s viewed normal to said TFT substrate,said channel having a channel length larger at an edge portion of said channel adjacent to one of said pixels than at a central portion thereof, whereupon leakage current of said TFT at said edge portion is suppressed.
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Litigations
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Accused Products
Abstract
An amorphous-silicon TFT (thin-film-transistor) in an LCD device has a larger channel length at both the edge portions of the channel of the TFT compared to the central portion of the channel by forming chamfers at the corners of the source and drain electrodes. The larger channel length at both the edge portions reduces the leakage current caused by the turned-around light incident onto the channel.
4 Citations
21 Claims
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1. A liquid crystal display (LCD) device comprising a TFT (thin-film-transistor) substrate mounting thereon a plurality of TFTs each having a channel in an ohmic contact layer and a semiconductor layer;
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a counter substrate mounting thereon a black matrix; a liquid crystal layer sandwiched between said TFT substrate and said counter substrate; a backlight unit disposed at a rear side of said TFT substrate for irradiating said TFT substrate with backlight, said counter substrate mounting thereon a light shield overlapping said channel of said TFTs as view normal to said counter substrate; and a rear shield film interposed between said channel of said TFTs and said backlight unit to overlap said channel of said TFTs s viewed normal to said TFT substrate, said channel having a channel length larger at an edge portion of said channel adjacent to one of said pixels than at a central portion thereof, whereupon leakage current of said TFT at said edge portion is suppressed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A liquid crystal display (LCD) device comprising a TFT (thin-film-transistor) substrate mounting thereon a plurality of TFTs, a counter substrate mounting thereon a black matrix, a liquid crystal layer sandwiched between said TFT substrate and said counter substrate for defining an array of pixels, and a backlight unit disposed at a rear side of said TFT substrate for irradiating said TFT substrate with backlight, each of said TFTs having a channel in an ohmic contact layer and a semiconductor layer, said channel being aligned, as viewed normal to said substrates, with said black matrix and a light shield layer disposed between said channel and said backlight unit,
said channel having a channel length larger at an edge portion of said channel adjacent to one of said pixels than at a central portion thereof.
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13. A liquid crystal display (LCD) device comprising a thin-film-transistor (TFT) substrate mounting thereon a plurality of TFTs, a counter substrate mounting thereon a black matrix, a liquid crystal layer sandwiched between said TFT substrate and said counter substrate for defining an array of pixels, each of said pixels including one of said TFTs and an associated pixel electrode, and a backlight unit disposed at a rear side of said TFT substrate for irradiating said TFT substrate with backlight, each of said TFTs having a channel in an ohmic contact layer and a semiconductor layer, said channel being aligned, as viewed normal to said substrates, with said black matrix and a light shield layer disposed between said channel and said backlight unit,
said channel having a channel length larger at both edge portions of said channel than at a central portion thereof.
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15. A liquid crystal display (LCD) device comprising a TFT (thin-film-transistor) substrate mounting thereon a plurality of TFTs, a counter substrate mounting thereon a black matrix, a liquid crystal layer sandwiched between said TFT substrate and said counter substrate for defining an array of pixels, and a backlight unit disposed at a rear side of said TFT substrate for irradiating said TFT substrate with backlight, each of said TFTs having a channel in an ohmic contact layer and a semiconductor layer, said channel being aligned, as viewed normal to said substrates, with said black matrix and a light shield layer disposed between said channel and said backlight unit,
said channel having a channel length larger at an edge portion of said channel adjacent to one of said pixels than at a central portion thereof, wherein said edge of said channel has a stepwise portion wherein said channel length increases toward said edge portion.
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16. A liquid crystal display (LCD) device comprising a thin-film-transistor (TFT) substrate mounting thereon a plurality of TFTs, a counter substrate mounting thereon a black matrix, a liquid crystal layer sandwiched between said TFT substrate and said counter substrate for defining an array of pixels, each of said pixels including one of said TFTs and an associated pixel electrode, and a backlight unit disposed at a rear side of said TFT substrate for irradiating said TFT substrate with backlight, each of said TFTs having a channel in an ohmic contact layer and a semiconductor layer, said channel being aligned, as viewed normal to said substrates, with said black matrix and a light shield layer disposed between said channel and said backlight unit,
said channel having a channel length larger at both edge portions of said channel than at a central portion thereof, wherein said edge portions of said channel have stepwise portions wherein said channel length increases toward said edge portion.
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20. A liquid crystal display (LCD) device comprising a TFT (thin-film-transistor) substrate mounting thereon a plurality of TFTs each having a channel in an ohmic contact layer and a semiconductor layer;
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a counter substrate mounting thereon a black matrix; a liquid crystal layer sandwiched between said TFT substrate and said counter substrate; a backlight unit disposed at a rear side of said TFT substrate for irradiating said TFT substrate with backlight, said counter substrate mounting thereon a light shield overlapping said channel of said TFTs as view normal to said counter substrate; and a rear shield film interposed between said channel of said TFTs and said backlight unit to overlap said channel of said TFTs s viewed normal to said TFT substrate, said channel having a channel length lager at an edge portion of said channel adjacent to one of said pixels than at a central portion thereof, whereupon leakage current of said TFT at said edge portion is suppressed, wherein said TFT includes source and drain electrodes opposing said gate electrode with an intervention of said semiconductor layer, and the edge portion is chamfered. - View Dependent Claims (21)
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Specification
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Litigation Data
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Current AssigneeHannStar Display Corporation
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Original AssigneeNEC LCD Technologies Limited (NEC Corporation)
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InventorsHashimoto, Yoshiaki, Kimura, Shigeru, Suzuki, Seiji
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Primary Examiner(s)QI, ZHI QIANG
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Application NumberUS10/923,432Publication NumberTime in Patent Office1,565 DaysField of Search349 41- 43, 349/187US Class Current349/43CPC Class CodesG02F 1/1368 in which the switching elem...
