# US 5,708,484 A · TFT active matrix liquid crystal display devices with two layer gate lines, the first being the same level and material as gate electrodes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,708,484 A - Document ID: US5708484A - Status: Granted - Kind: A - Application number: 08/610,148 - Filed: 1996-02-29 - Granted: 1998-01-13 - Earliest claimed: 1987-06-10 - Assignees: Hitachi, Ltd. - Inventors: Sakae Someya; Ryuuzoh Nashimoto; Hirofumi Suzuki; Katsuhiko Yarita; Shinji Matsumoto; Akira Sasano; Hideaki Taniguchi; Ryouji Oritsuki - Web page: https://patentgrep.com/patent/US5708484A ## CPC - G02F 1/136286: {Wiring, e.g. gate line, drain line} - G02F 1/136213: {Storage capacitors associated with the pixel electrode} - G02F 1/13624: {having more than one switching element per pixel} - G09G 3/3607: {for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels (display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127)} - G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)} - G09G 3/3659: {the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes} - G02F 1/133512: {Light shielding layers, e.g. black matrix (G02F1/136209 takes precedence)} - G02F 1/136268: {Switch defects} - G02F 1/13629: {Multilayer wirings} - G09G 2300/0426: Layout of electrodes and connections - G09G 2300/0452: Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components - G09G 2300/0809: Several active elements per pixel in active matrix panels - G09G 2320/0219: Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling - G09G 2330/08: Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract There are disclosed various types of TFT active matrix liquid crystal display devices in which a pixel is divided into three parts, a capacitor is added to each pixel, light shielding is applied to each TFT, and the matrix is driven by a DC cancelling technique. ## Claims ### Claim 1 A liquid crystal display device having a plurality of pixels, each of said plurality of pixels including a thin film transistor, a pixel electrode and a holding capacitance element and disposed in each of intersecting regions defined by two adjacent scanning signal lines and by two adjacent image signal lines, wherein: each said thin film transistor comprises a gate electrode electrically connected to one of said two adjacent scanning signal lines associated therewith, a gate insulating film disposed on said gate electrode, a semiconductor layer disposed on said gate insulating film, and a source electrode and a drain electrode electrically connected to said semiconductor layer, respectively, one of said source electrode and drain electrode of each said thin film transistor is electrically connected to said pixel electrode associated therewith, the other of said source electrode and drain electrode of each said thin film transistor being electrically connected to one of said two adjacent image signal lines associated therewith, said scanning signal lines include a first conductive film and a second conductive film superposing with each other, said holding capacitance element of each pixel comprises a first electrode electrically connected to said pixel electrode, a second electrode electrically connected to the other of said two adjacent scanning signal lines associated therewith, and a dielectric film interposed therebetween, and said second electrode and said gate electrode are formed from a same conductive layer only, which conductive layer is a same level layer as that of said first conductive film of said scanning signal lines. ### Claim 2 (depends on 1) A liquid crystal display device according to claim 1, wherein said second conductive film has a smaller width than that of said first conductive film at least in crossover portions of said scanning signal lines and said image signal lines. ### Claim 3 (depends on 2) A liquid crystal display device according to claim 2, wherein each said gate electrode is directly connected to said first conductive film and is disposed in a non-overlapped relationship with said second conductive film of said one of said two adjacent scanning signal lines associated therewith. ### Claim 4 (depends on 2) A liquid crystal display device according to claim 2, wherein said second electrode of each said holding capacitance element is disposed in a non-overlapped relationship with said second conductive film of said other of said two adjacent scanning signal lines associated therewith. ### Claim 5 (depends on 2) A liquid crystal display device according to claim 2, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer. ### Claim 6 (depends on 1) A liquid crystal display device according to claim 1, wherein each said gate electrode is directly connected to said first conductive film and is disposed in a non-overlapped relationship with said second conductive film of said one of said two adjacent scanning signal lines associated therewith. ### Claim 7 (depends on 6) A liquid crystal display device according to claim 6, wherein said second electrode of each said holding capacitance element is disposed in a non-overlapped relationship with said second conductive film of said other of said two adjacent scanning signal lines associated therewith. ### Claim 8 (depends on 1) A liquid crystal display device according to claim 1, wherein said second electrode of each said holding capacitance element is disposed in a non-overlapped relationship with said second conductive film of said other of said two adjacent scanning signal lines associated therewith. ### Claim 9 (depends on 1) A liquid crystal display device according to claim 1, wherein each said gate electrode is directly connected to said first conductive film and is left uncovered by said second conductive film of said one of said two adjacent scanning signal lines associated therewith. ### Claim 10 (depends on 9) A liquid crystal display device according to claim 9, wherein said second electrode of each said holding capacitance element is left uncovered by said second conductive film of said other of said two adjacent scanning signal lines associated therewith. ### Claim 11 (depends on 1) A liquid crystal display device according to claim 1, wherein said second electrode of each said holding capacitance element is left uncovered by said second conductive film of said other of said two adjacent scanning signal lines associated therewith. ### Claim 12 (depends on 1) A liquid crystal display device according to claim 1, wherein each said gate electrode is formed from a part of said first conductive film which is left uncovered by said second conductive film of said one of said two adjacent scanning signal lines associated therewith and which is extended as a branched portion in an orthogonal direction from the direction of said scanning signal lines, which orthogonal direction is substantially parallel to the direction of said image signal lines. ### Claim 13 (depends on 12) A liquid crystal display device according to claim 12, wherein said second electrode of said holding capacitance element of each pixel is formed from a part of said first conductive film which is left uncovered by said second conductive film of said other of said two adjacent scanning signal lines associated therewith and which is extended as a branched portion in a direction parallel but opposite the direction of the uncovered part of said first conductive film of said one scanning line which forms the gate electrode of said thin film transistor of that pixel. ### Claim 14 (depends on 13) A liquid crystal display device according to claim 13, wherein said second conductive film has a smaller width than that of said first conductive film at least in crossover portions of said scanning signal lines and said image signal lines. ### Claim 15 (depends on 14) A liquid crystal display device according to claim 14, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer. ### Claim 16 (depends on 13) A liquid crystal display device according to claim 13, wherein said first and second conductive films constituting each of said scanning signal lines are dimensioned such that said second conductive film has a smaller width than said first conductive film. ### Claim 17 (depends on 16) A liquid crystal display device according to claim 16, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer. ### Claim 18 (depends on 12) A liquid crystal display device according to claim 12, wherein said second conductive film has a smaller width than that of said first conductive film at least in crossover portions of said scanning signal lines and said image signal lines. ### Claim 19 (depends on 12) A liquid Crystal display device according to claim 12, wherein said first and second conductive films constituting each of said scanning signal lines are dimensioned such that said second conductive film has a smaller width than said first conductive film. ### Claim 20 (depends on 1) A liquid crystal display device according to claim 1, wherein said first and second conductive films constituting each of said scanning signal lines are dimensioned such that said second conductive film has a smaller width than said first conductive film. ### Claim 21 (depends on 1) A liquid crystal display device according to claim 1, wherein said plurality of pixels are arranged, on a substrate surface, together with a plurality of scanning signal lines and a plurality of image signal lines to form a matrix array having rows and rows of pixels in which each pixel is disposed in each of intersecting regions on said substrate surface defined by a pair of adjacent scanning signal lines and by a pair of adjacent image signal lines, said pair of scanning signal lines, respectively, being associated with adjacent pixels in a column direction and said pair of image signal lines, respectively, being associated with adjacent pixels in a row direction of said matrix array. ### Claim 22 (depends on 21) A liquid crystal display device according to claim 21, wherein each said gate electrode is formed from a part of said first conductive film which is left uncovered by said second conductive film of said one of said two adjacent scanning signal lines associated therewith and which is extended as a branched portion of that scanning line in the row direction. ### Claim 23 (depends on 22) A liquid crystal display device according to claim 22, wherein said second electrode of said holding capacitance element of each pixel is formed from a part of said first conductive film which is left uncovered by said second conductive film of said other of said two adjacent scanning signal lines associated therewith and which is extended as a branched portion in the column direction but opposite that of the uncovered part of said first conductive film of said one scanning signal line which forms the gate electrode of said thin film transistor of that pixel. ### Claim 24 (depends on 23) A liquid crystal display device according to claim 23, wherein said second conductive film has a smaller width than that of said first conductive film at least in crossover portions of said scanning signal lines and said image signal lines. ### Claim 25 (depends on 23) A liquid crystal display device according to claim 23, wherein said first and second conductive films constituting each of said scanning signal lines are dimensioned such that said second conductive film has a smaller width than said first conductive film. ### Claim 26 (depends on 25) A liquid crystal display device according to claim 25, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer. ### Claim 27 (depends on 22) A liquid crystal display device according to claim 22, wherein said second conductive film has a smaller width than that of said first conductive film at least in crossover portions of said scanning signal lines and said image signal lines. ### Claim 28 (depends on 22) A liquid crystal display device according to claim 22, wherein said first and second conductive films constituting each of said scanning signal lines are dimensioned such that said second conductive film has a smaller width than said first conductive film. ### Claim 29 (depends on 28) A liquid crystal display device according to claim 28, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer. ### Claim 30 (depends on 21) A liquid crystal display device according to claim 21, wherein said second electrode of said holding capacitance element and said gate electrode of said thin film transistor in each of said pixels are formed from a same conductive layer as that used for forming said first conductive film of said scanning lines. ### Claim 31 (depends on 21) A liquid crystal display device according to claim 21, wherein said second electrode of said holding capacitance element and said gate electrode of said thin film transistor in each of said pixels are formed from branched portions of said one and said other of said two adjacent scanning signal lines associated therewith, respectively. ### Claim 32 (depends on 1) A liquid crystal display device according to claim 1, wherein said second electrode of said holding capacitance element and said gate electrode of said thin film transistor in each of said pixels are formed from a same conductive layer as that used for forming said first conductive film of said scanning lines. ### Claim 33 (depends on 32) A liquid crystal display device according to claim 32, wherein said second conductive film has a smaller width than that of said first conductive film at least in crossover portions of said scanning signal lines and said image signal lines. ### Claim 34 (depends on 33) A liquid crystal display device according to claim 33, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer. ### Claim 35 (depends on 32) A liquid crystal display device according to claim 32, wherein said first and second conductive films constituting each of said scanning signal lines are dimensioned such that said second conductive film has a smaller width than said first conductive film. ### Claim 36 (depends on 35) A liquid crystal display device according to claim 35, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer. ### Claim 37 (depends on 1) A liquid crystal display device according to claim 1, wherein said second electrode of said holding capacitance element and said gate electrode of said thin film transistor in each of said pixels are formed from branched portions of said one and said other of said two adjacent scanning signal lines associated therewith, respectively. ### Claim 38 (depends on 37) A liquid crystal display device according to claim 37, wherein said second conductive film has a smaller width than that of said first conductive film at least in crossover portions of said scanning signal lines and said image signal lines. ### Claim 39 (depends on 38) A liquid crystal display device according to claim 38, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer. ### Claim 40 (depends on 37) A liquid crystal display device according to claim 37, wherein said first and second conductive films constituting each of said scanning signal lines are dimensioned such that said second conductive film has a smaller width than said first conductive film. ### Claim 41 (depends on 40) A liquid crystal display device according to claim 40, wherein said first conductive film consists of a chromium film layer and said second conductive film consists of an aluminum film layer.