United States Patent
`
`[19]
`
`[11] Patent Number:
`
`4,781,438
`
`Noguchi
`
`[45] Date of Patent:
`
`Nov. 1, 1988
`
`[54] AC'I‘IVE-MATRIX LIQUID CRYSTAL COLOR
`DISPLAY PANEL HAVING A TRIANGULAR
`PIXEL ARRANGEMENT
`
`[75]
`
`Inventor:
`
`Kesao Noguchi, Tokyo, Japan
`
`[73] Assignee:
`
`NEC Corporation, Japan
`
`[21] Appl. No.: 149,629
`
`[22] Filed:
`
`Jan. 28, 1988
`
`Foreign Application Priority Data
`[30]
`Jan. 28, 1987 [JP]
`Japan ................................ .. 62-19100
`
`Int. c1.4 .............................................. .. G02F 1/13
`[51]
`[52] U.S. c1. .............................. .. 350/339 F; 350/333,
`350/336; 340/784
`[58] Field of Search ................... 1, 350/333, 336, 339 F
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`3,840,695 10/1974 Fischer ......................... .. 350/345 X
`4,368,523
`1/1983 Kawate ................. .. 350/333 X
`
`4,568,149
`2/1986 Sugata et al. ......... .. 350/339 F X
`
`~ 4,589,733
`5/1986 Yaniv et al. ................ 350/333 X
`4,704,559 11/1987 Suginoya et al.
`......... .. 350/339 F X
`
`4,743,099
`
`5/1988 Dickerson et al.
`
`........... .. 350/333 X
`
`FOREIGN PATENT DOCUMENTS
`
`2l30781A 6/1984 United Kingdom .............. .. 350/333
`
`Primary Examz'ner—Stanley D. Miller
`Assistant Examz'ner—Richard Gallivan
`Attorney, Agent, or Firm—Laff, Whitesel, Conte & Saret
`
`[57]
`
`ABSTRACT
`
`An active-matrix liquid crystal color display panel in-
`cludes lines of color pixel elements composed of first,
`second and third types of cell elements, each cell ele-
`ment having two display electrodes each connected to a
`video signal bus running therebetween through paral-
`lely connected two thin film FET’s (TFT’s) having
`gates connected to different scanning signal buses, the
`first, second and third types of cell elements having
`different one of three primary color filters, and repeti-=
`tion of the color pixel elements in adjacent line being
`shifted with a half length of the color pixel element to
`form triangular color pixel arrangement.
`
`12 Claims, 6 Drawing Sheets
`
`
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`U.S. Patent
`
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`

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`U.S. Patent
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`Nov. 1,1988
`
`Sheet 2 of6
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`4,781,438
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`E
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`FIG.3
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`US. Patent
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`Nov. 1,1988
`
`Sheet 3 of 6
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`4,781,438
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`U.S. Patent
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`Nov. 1, 1988
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`Sheet 4 of6
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`4,781,438
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`I53
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`
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`FIG. 8
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`US. Patent
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`Nov. 1,1988
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`Sheet 5 Of6
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`4,781,438
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`(ON)
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`(OFF)
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`(ON)
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`U.S. Patent
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`Nov. 1,1988
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`Sheet 6 of6
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`4,781,438
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`FIG‘..9
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`1
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`4,781,438
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`ACTIVE-MATRIX LIQUID CRYSTAL COLOR
`DISPLAY PANEL HAVING A TRIANGULAR
`PIXEL ARRANGEMENT
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`This invention relates to an active-matrix liquid crys-
`tal color display panel having a triangular pixel arrange-
`ment, and more particularly to an improvement for high
`quality color image.
`2. Description of the Related Art
`Recently, a liquid crystal color display panel has been
`remarkably progressed and is demanded to image a high
`quality color picture. An active-matrix liquid crystal
`display panel using thin film field effect
`transistors
`(hereinafter, referred to TFT) as switches has been
`recognized, in recent years, as preferable to image a fine
`high quality color image.
`One pixel element is formed of a TFT and a display
`electrode. A plurality of pixel elements are disposed in
`a matrix form on a transparent glass substrate. The
`TFT’s are driven by access signal buses (or scanning
`buses) and data signal buses (or video signal buses) dis-
`posed between pixel elements to form a lattice. Scan-
`ning signals are applied to TFT’s through the access
`buses. Video signals are applied to the data buses to be
`supplied to selected display electrodes through TFT’s
`which are turned on by the scanning signals.
`In a color display, one color pixel element has three
`or four pixel elements (hereinafter, referred to cell ele-
`ment for imaging primary color components. There-
`fore, compared to a black-and-white display, number of
`cell elements required is more than three times. The
`larger the number of color pixel elements (that is, the
`number of cell elements), the higher the resolution of
`the obtained color image becomes. However,
`if the
`number of cell elements is increased, the time duration
`for driving one cell element becomes short to decrease
`the effective voltage applicable to liquid crystal, result-
`ing in a poor quality of imaged picture. In this point of
`view, the activematrix liquid crystal color display panel
`is superior to other types of liquid crystal display panel.
`The activematrix type is small in decrease of the effec-
`tive voltage applied to liquid crystal, if the driving time
`duration becomes short. However, in a case where the
`number of cell elements are greatly increased for ob-
`taining a high quality color image, the driving time
`duration becomes too short to apply the sufficient effec-
`tive voltage to the liquid crystal in the active-matrix
`type color display panel.
`An arrangement for prolonging this driving time
`duration is to form one cell element with one display
`electrode and two TFT’s and to successively drive
`those two TFT’s by adjacent two access buses. By this
`arrangement, the time duration for applying a video
`signal to one display electrode becomes double, com-
`pared to the case where one TFT is coupled to one
`display electrode. However, since one access bus simul-
`taneously drives adjacent two cell elements in the direc-
`tion parallel with data signal bus, all the cell elements in
`the direction parallel with the data bus have to receive
`a video signal of the same color. This means the primary
`color pixel arrangement is limited to be a stripe type.
`The stripe type color pixel arrangement has the same
`color cell elements in a line and is poor in image quality.
`The image quality is improved by the triangular color
`pixel arrangement. K. Noguchi et al. proposed one
`
`10
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`15
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`20
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`2
`improvement for the triangular color pixel element in
`U.S. patent application (Ser. No. 823,104) filed on Jan.
`27, 1986. One cell element in one color is divided into
`two parts each having one TFT and one display elec-
`trode. The drain electrodes and gate electrodes of the
`two TFT’s are connected to the same data bus and the
`same access bus. The two-part-set cell elements are
`connected to every access buses. But every other two-
`part-set cell elements are disposed on one side of the
`access buses, while the other two-part-set cell element
`are disposed on the other side of the access buses. Two
`two-part-set cell elements on one side of the access bus
`and one two-part-set cell element on the other side of
`the access bus form one color pixel element having a
`triangular shape. The arrangement of the color pixel
`elements along the access buses is shifted with a half
`pitch of one color pixel element between adjacent two
`access buses. This arrangement images a high quality
`picture. However,
`there is one drawback of a line-
`defect which appears if one access bus or data bus has
`an opencircuit introduced in a manufacturing process.
`This linedefect spoils the imaged picture.
`SUMMARY OF THE INVENTION
`
`It is a primary object of the present invention to pro-
`vide an active-matrix liquid crystal color display panel
`having a high density of pixel elements and imaging a
`high quality picture which is not spoiled by a small
`number of open—circuits in access buses.
`According to the present invention, there is provided
`an active-matrix liquid crystal color display panel com-
`prising a plurality of access signal buses (or scanning
`lines), a plurality of data signal buses (or video signal
`lines) orthogonaly crossing but separated from the ac-
`cess buses, a matrix of display electrodes formed of a
`plurality of columns parallel with the access buses and
`rows parallel with the data buses, each of the display
`electrodes being disposed in a space surrounded by two
`adjacent access buses and two adjacent data buses, a
`plurality of switching transistors having a gate elec-
`trode, a drain electrode and a source electrode, each of
`the display electrodes being connected to the source
`electrodes of two switching transistors, the gate elec-
`trodes of the two switching transistors being connected
`to the adjacent two access buses running both sides of
`the display electrode which is connected to the source
`electrodes of the two switching transistors, and the
`drain electrodes of the switching transistors having
`source electrodes connected to a pair of adjacent two
`display electrodes along the access buses being con-
`nected to the same data bus running between the pair of
`two display electrodes, each pair of two display elec-
`trodes in every other columns of the display electrode
`matrix being formed of two display electrodes on both
`sides of every other data buses and each pair of two
`display electrodes in the other columns being formed of
`two display electrodes on both sides of the other data
`buses, and a color filter having a plurality of filters each
`covering the pair of display electrodes and transmitting
`predetermined color components, filters transmitting
`different color components being repeatedly arranged
`in lines above the columns of display electrodes, the
`arrangement of the filters being shifted between adja-
`cent lines with a half of total length of the filters to form
`a color pixel.
`invention, one display electrode is
`In the present
`supplied with video signals from the same data bus
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`3
`through two switching transistorsdriven by adjacent
`two access buses. The time duration for being supplied
`with video signal is prolonged. Therefore, in an active-
`matrix liquid crystal color display panel having an in-
`creased number of pixel elements, high effective voltage 5
`can be applied to the liquid crystal to image a high
`quality picture. Furthermore, since one display elec-
`trode is connected to adjacent two access buses through
`switching transistors, small number of open-circuits in
`access buses does not affect the imaged picture. The 10
`display electrodes coupled to the open-circuited access
`bus can be made access from the other access bus hav-
`
`ing no openocircuit. Thus, the present invention images
`a high-quality natural picture with increased number of
`color pixel elements driven by a high effective signal 15
`voltage, even if small number of open-circuits exist in
`access buses.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The above and further objects, features and advan-
`tages of the present invention will become more appar-
`ent from the following detailed description taken in
`conjunction with the accompanying drawings, wherein:
`FIG. 1 is a schematic plan view of a part of an active-
`matrix liquid crystal color display panel in the prior art;
`FIG. 2 is a schematic plan view of a part of another
`active-matrix liquid crystal color display panel
`in a
`prior art;
`FIG. 3 is a schematic plan view of a part of an active-
`matrix liquid crystal color display panel according to a
`first preferred embodiment of the present invention;
`FIG. 4 is a plan view of a part of TFT array board
`used in the first preferred embodiment of the present
`invention;
`FIG. 5 is a sectional view taken along A—A' of FIG.
`
`4;
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`FIG. 6 is a timing chart of scanning pulses and a
`voltage applied to the liquid crystal in a non-interlacing
`operation of the first preferred embodiment;
`FIGS. 7(a) and 7(b) are schematical diagrams of a
`part of first preferred embodiment shown in FIGS. 3, 4
`and 5, for explaining an interlacing operation;
`FIG. 8 is a timing chart of scanning pulses and a
`voltage applied to the liquid crystal in an interlacing
`operation of the first preferred embodiment; and
`FIG. 9 is a schematic plan view of the active-matrix
`liquid crystal color display panel according to the sec-
`ond preferred embodiment of the present invention.
`First prior art of an active-matrix liquid crystal color 50
`display panel has display electrodes 80 supplied with
`video signals through two TFT’s 83 and 84 driven by
`adjacent two access buses 82, as shown in FIG. 1. A
`plurality of sets of the display electrode 80 and a pair of
`IF I’s 83 and 84, a plurality of parallely arranged access 55
`buses 82 and a plurality of data buses 81 disposed or-
`thogonally to the access buses 82 are formed on a trans-
`parent glass substrate. Every one display electrode 80
`positions in every one space surrounded by two access
`buses 82 and two data buses 81 and connected to source
`electrodes of the pair of TFT’s 83 and 84. Source elec-
`trodes of the pair of the TFT’s 83 and 84 are connected
`to their left-side data bus 81. The display electrodes 80
`labeled as “C1”, “C2” and “C3” form one color pixel
`element by covered respectively with red, green and
`blue filters. In the lines of the access buses 82, the red,
`green and blue filters cover repeatedly the display elec-
`trodes 80.
`
`65
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`4,781,438
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`The access buses 82 are scanned to drive selected
`TFT’s. Video signal is supplied to the display electrodes
`80 through the data buses 81 and the driven TFT’s.
`Therefore, one display electrodes 80 are supplied with
`the video signal for a time period when the TFT’s 83
`and 84 are driven. The time periods are double, com-
`pared to a time period when one TFT is driven. This
`results in that a sufficient effective voltage for driving
`liquid crystal is applied to the display electrode. In
`other words, the number of color pixel element can be
`increased without lowering the effective video voltages
`at the display electrodes 80.
`.
`However, since the video signal is supplied through
`the data buses 81 and one access bus drives two TFT’s
`coupled to two display electrodes on both sides of the
`access bus, all the filters covering display electrodes 80
`aligned in parallel with data buses must be same color.
`Thus color filter is limited to a stripe type. The image
`displayed by the stripe type color filter is poor in quality
`and is not natural.
`
`The natural image can be improved by use of a color
`filter having a triangular color pixel elements. An ac-
`tive-matrix liquid crystal color display using the color
`filter having a triangular color pixel elements is drawn
`in FIG. 2. One cell element has a pair of TFT’s 73 and
`74 and a pair of display electrodes 75 and 76. Each
`display electrode is supplied with a video signal through
`a bus 71 and a TFT. The display electrodes are disposed
`on both sides of one bus 72. Gate electrodes of a pair of
`TFT’s 73 and 74. The pairs of display electrodes cou-
`pled to every other data buses are disposed on one side
`of the access bus 72 while the other pairs of display
`electrodes coupled to the other data buses are disposed
`on the other side of the access bus. The display elec-
`trodes labeled as “C1”, “C2” and “C3” form one color
`pixel element by covered with red, green and blue fil-
`ters, respectively. On lines of display electrodes aligned
`in parallel with access buses, an arrangement of an order
`of red (C1), red (C1), blue (C3), blue (C3), green (C2) and
`green (C2) filters is repeated. The filter arrangement is
`shifted between adjacent two lines of display electrodes
`with a half pitch of the the repetition cycle of the color
`filters to form triangular color pixel elements which are
`formed of two pairs of display electrodes in one line and
`one pair of display electrodes in an adjacent line.
`Each color pixel element overlaps with adjacent
`color pixel elements in plan view. Repetition of primary
`colors is not clear to image a natural picture. However,
`there is a drawback that one open-circuit in an access
`bus results in a loss of operability of all TFT’s coupled
`to the defective access bus. Thus, two lines of display
`electrodes on both sides of the defective bus are not
`supplied with video signal. A line defect appears on a
`imaged picture.
`
`DESCRIPTION OF PREFERRED EMBODIMENT
`
`One cell element in an active-matrix liquid crystal
`color display panel according to a first preferred em-
`bodiment has a pair of display electrodes 15 and 16, as
`shown in FIG. 3. The display electrodes 15 is connected
`to a source electrode of a TFT 13 which has a gate
`electrode connected to a gate bus 12 running on an
`upper side of the pair of display electrodes 15 and 16
`and a drain electrode connected to a data signal bus 11
`running between the pair of display electrodes 15 and
`16. The display electrode 15 is also connected to a
`source electrode of a TFT 17 which has a gate electrode
`connected to an access signal bus 12 running on a lower
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`color filter 130 is located thereon. The color filter 130
`side of the pair of display electrodes 15 and 16 and a
`drain electrode connected to the same data signal bus
`has a plurality of red, green and blue filter elements 132
`on a transparent glass board 131. The arrangement of
`11. Similarly,
`the other display electrode 16 is con-
`nected to source electrodes of two TFT’s 14 and 18.
`the red, green and blue filter elements 132 is as ex-
`The gate electrodes of the two TFT’s 14 and 18 are 5 plained with reference to FIG. 3.
`respectively connected to gate buses 12 running on
`The color pixel elements have a triangular form and
`upper and lower sides of the pair of display electrodes
`overlap with their side color pixel elements in plan
`15 and 16. The drain electrodes of the two TFT’s 14 and
`view. The imaged picture does not generate moire-
`18 are connected commonly to the same data bus 11
`image interference fringes. Color uniformity is superior
`running between the pair of display electrodes 15 and 10 to feel the imaged picture natural. Thus, since the color
`16.
`display panel has a triangular color pixel arrangement, a
`A plurality of the cell elements are formed at every
`high quality image can be produced. Furthermore, one
`other data bus and form a line of cell elements. The lines
`display element is supplied with video signal through
`of cell elements are formed in every region between
`two TFT’s having gates connected to different access
`two adjacent access buses 12. The data buses connected 15 buses. Therefore, if one access bus has an open-circuit,
`the display electrode can be made access by means of
`to the pixel elements are different between the neigh-
`the other access bus. A line defect does not appear on an
`bouring lines of cell elements.
`The cell elements, the data buses and the access buses
`imaged picture. The open-circuit may occur in a manu-
`facturing process of the TFT array board. The allow-
`are formed on a transparent glass substrate to form a
`ance of the small number of open-circuits in access
`TFT array board. A layer of liquid crystal and a com-
`mon electrode thereon connected to a reference poten-
`buses raises a production yield and lowers the produc-
`tion cost.
`tial cover the TFT array board and a layer of color
`The two-TFT structure has another merit. A scan-
`filter is formed thereon. The color filter includes red
`filter elements “R”, green filter elements “G” and blue
`filter elements “B” which are respectively positioned
`above the respective display electrodes. Each filter
`element may have an area covering each of the display
`electrodes 15 and 16 or each pair of the display elec-
`trodes 15 and 16. On a line of cell elements, the arrange-
`ment of the red filter element(s), the green filter ele-
`ment(s) and the blue filter element(s) is repeated. The
`repetition of the filter element arrangement is shifted
`between neighbouring lines of the cell elements with a
`half of a repetition pitch. This shift forms a triangular
`color pixel element as shown by hatched display elec-
`trodes.
`
`ning pulse of +15 volts is sequentially applied to the
`access buses 12 from upper one to lower one, while
`video signals of +(8:l:x) volts are supplied to the data
`buses 11 in synchronism with the scanning pulse. The
`value x is varied depending on the tone of the picture.
`For imaging color picture, red, green and blue video
`signals are supplied. As apparent from FIG. 3, respec-
`tive data buses 11 may be supplied with only one of the
`red, green and blue video signals. This fact simplifies
`the peripheral circuit for operating the color display
`panel.
`Furthermore, in a non-interlacing operation, the ac-
`cess buses 12 are successively driven by a scanning
`pulse in an order from upper one to lower one. FIG. 6
`The active-matrix liquid crystal color display panel
`shows a timing chart of the scanning pulses applied to
`will be further explained in more practical form. A part
`the even number of access bus VG2,, and the next access
`of TFT array board and a partial section of the color
`bus VG2,,+1 and voltage V1_c applied to the liquid crys-
`display panel are shown in FIGS. 4 and 5 with same
`tal. Since the video signals are supplied to one display
`reference numerals. A plurality of access buses 125
`electrode for succeeding two periods (2t) when the
`serving as gate electrodes are formed in parallel with
`scanning pulses 151 and 152 are applied to succeeding
`one another on a transparent glass substrate 126 with
`two access buses, the time 2t for supplying the video
`chromium (Cr) of 1500 A and covered with an insulator
`signal to one display electrode becomes double, as com-
`film 127 of silicon nitride of 3,000 A. Amorphous Si
`pared to a case where one TFT is connected to one
`films 122 of n“-type are formed with a thickness of
`2,000 A on the insulator film 127 above the access buses
`display electrode. The voltage applied to the liquid
`crystal decreases with a time constant CR,,ff after the
`125 to operate as channel regions of TFT’s. N+-amo1;-
`pulse 152 disappears. Since the liquid crystal is suffi-
`phous Si films 124 are formed with a thickness of 200 A
`as source and drain regions on the amorphous Si films 50 ciently charged for the elongated charging time 2t, the
`122. Drain electrodes 121 and data buses 111 are formed
`voltage VLC is kept at high for scanning period T to
`on the N+-amorphous Si films 124 and on the insulator
`increase the effective voltage applied to the liquid crys-
`film 127, with Cr of 3,000 A. The data buses 111 are
`tal. The contrast of imaged picture is improved to ob-
`arranged to be in parallel with one another and to cross
`tain a high quality picture. In other words, the picture
`orthogonally the access buses 125. The source elec- 55 quality is not deteriorated by increasing the number of
`trodes 123 is formed with Cr of 3,000 A to cover the
`color pixel elements. Although an access time to one
`N+-amorphous Si films 124 of the source regions and
`access bus decreases by increasing the cell element
`side wall of the amorphous Si films 122. A plurality of
`number, the access time to one display electrode does
`display electrodes 129 of ITO having a thickness of
`not become short. A fine, high contrast and wide image
`1,500 A are formed on regions of the insulator film 127 60 can be obtained.
`surrounded by two access buses 125 and two data buses
`The invention is also advantageous in interlacing
`111. The peripheral portion of each display electrode
`operation. An odd number of field is schematically
`129 is overlapped with the source electrode 123 to
`shown in FIG. 7(a), an even number of field being sche-
`which the display electrode is to be connected. The
`matically shown in FIG. 7(b). FIGS. 7(a) and 7(b) are
`TFT’s and the display electrodes 129 are covered with 65 simplified diagram of FIG. 3 for explaining the interlac-
`ing operation. In an odd number of field, access buses
`a protection film 128 of polyimide. Liquid crystal 135 is
`G1, G3, G5 .
`.
`. are sequentially supplied with scanning
`interposed between the TFT array board 120 and a
`common electrode 134 which is connected to ground. A
`pulses. Each access bus turns on TFT’s on both sides to
`
`35
`
`45
`
`SEC v. Surpass Tech, |PR2015—OO887
`SAMSUNG EX. 1026 — 10/12
`
`SEC v. Surpass Tech, IPR2015-00887
`SAMSUNG EX. 1026 - 10/12
`
`

`
`4,781,438
`
`5
`
`15
`
`8
`7
`pixel element may be increased without decreasing a
`.
`.
`supplied video signals to the display electrodes P,,,,1 .
`high quality imaged picture, a small number of opencir-
`P,,,,4 and P,,.+1,1 .
`.
`. Pm+1, 4 .
`.
`. on both sides through
`data buses D1 .
`.
`. D5 .
`.
`.
`. Finally, all the display elec-
`cuits does not lower the imaged quality, a simplified
`trodes P11, .
`.
`. P44. .
`. are supplied with video signals in
`peripheral circuit is required for imaging a color pic-
`ture.
`on even number field. In an odd number field, the other
`What is claimed is:
`access buses G2, G4 .
`.
`. are sequentially supplied with
`1. An active-matrix liquid crystal color display panel
`the scanning pulse. Similarly to the even number field,
`comprising:
`all the display electrodes P11 .
`.
`. P44 .
`.
`. are supplied
`a transparent insulator substrate;
`with video signals in one odd number field.
`a plurality of access signal buses formed on said insu-
`The scanning pulses applied to the even number ac- 10
`lator substrate in parallel with one another;
`cess buses V02” and applied to the next access buses
`a plurality of data signal buses formed on said insula-
`VG2,,.1.1 is shown in FIG. 8 together with the voltage
`tor substrate to cross orthogonally said access sig-
`VLC applied to the liquid crystal. The video signals are
`nal buses;
`twice applied to the liquid crystal by the scanning
`a plurality of pixel elements formed on said insulator
`pulses 153 and 154.
`substrate, each pixel element including first and
`The liquid crystal is not fully charged during the
`second display electrodes and first
`to fourth
`period of the first scanning pulse 153 which has short-
`switching transistors, said first and second display
`ened pulse width for increasing pixel elements. After
`electrodes being respectively disposed in neigh-
`the first scanning pulse 153, the charges in the liquid
`bouring spaces surrounded by two access signal
`crystal are discharged witha time constant CRoff. Since 20
`buses and two data signal buses, said neighbouring
`the charges are not completely discharged until the
`spaces being arranged in the same direction as said
`second scanning pulse 154, charges are added to the
`access signal buses, said first and second switching
`liquid crystal by the second scanning pulse 154 to fully
`transistors having sources connected to said first
`increase the voltage VLC, resulted in an application of a
`display electrode, drains connected to the data
`high effective voltage to the liquid crystal. The in- 25
`signal bus running between said neighbouring
`creased effective voltage improves acontrast of imaged
`spaces and gates respectively connected to said
`picture to obtain a high quality. This high quality pic-
`two access signal buses, said third and fourth
`ture has been maintained in a display panel having 480
`switching transistors having sources connected to
`scanning lines (i.e. 480 access buses) operated by a
`said second display electrode, drains connected to
`frame frequency of 60 Hz with an access time of 35p. 30
`said data signal bus running between said neigh-
`sec.
`bouring spaces and gates respectively connected to
`The second preferred embodiment of the present
`said access signal buses, said pixel elements being
`invention shown in FIG. 9 has a constructional feature
`connected to every other data signal bus in stripe
`similar to the first preferred embodiment. Each cell
`regions between adjacent two access signal buses,
`element includes a pair of display electrodes 215 and 35
`and said data signal buses to which said pixel ele-
`216 and four TFT’s 213, 214, 217 and 218. The display
`ments are connected being different between adja-
`electrode 215 is connected to the TFT 213 controlled
`cent stripe regions;
`by an upper access bus 212 and to the TFT 217 con-
`a filter having a plurality of filter elements disposed
`trolled by a lower access bus 212’. The other display
`over said display electrodes, said filter elements
`electrode 216 is connected to the TFT 214 controlled 4-0
`permeating different color components and being
`by the upper access bus 212 and to the TF1‘ 218 con-
`repeatedly arranged in the same direction as said
`trolled by the lower access bus 212’. Red, green and
`access signal buses to form filter element lines, the
`blue filter elements in a color filter cover the display
`repetition of said filter elements being shifted be-
`electrodes via a liquid crystal layer and a common. elec-
`tween neighbouring filter element lines; and
`trode to form triangular color pixel elements (one being 45
`liquid crystal interposed between said first and sec-
`shown by hatching), similarly to the first preferred
`ond display electrodes and said filter.
`embodiment.
`2. An active-matrix liquid crystal color display panel
`A distinctive feature of the second preferred embodi-
`as claimed in claim 1, wherein said switching transistors
`ment is an interconnection 219 between the pair of dis-
`play electrodes 215 and 216. This interconnection 219 50 are thin film field effect transistors.
`may be formed of an ITO film formed on a data bus 211
`3. An active-matrix liquid crystal color display panel
`through additional insulator film of silicon nitride to
`as claimed in claim 2, wherein said thin film field effect
`connect the pair of display electrodes 215 and 216 made
`transistors have amorphous silicon as a channel region.
`of ITO.
`4. An active-matrix liquid crystal color display panel
`The same advantages, merits and features as the first 55 as claimed in claim 3, wherein said filter elements in-
`preferred embodiment may be obtained in this second
`clude first, second and third filter elements permeating
`preferred embodiment. Additionally, the interconnec-
`red, green and blue light, respectively.
`tions 219 give a redundancy to the TFT array board.
`5. An active-matrix liquid crystal color display panel
`Since the pair of display electrodes 215 and 216 are
`as claimed in claim 3, wherein said first and second
`electrically connected, even if one of TFT’s 213 and 214 60 display electrodes are electrically connected to each
`and one of TFT’s 217 and 218 are defective and not
`other.
`operable in a manufactured TFT array board, the TFT
`6. An active-matrix liquid crystal color display panel
`array board may be employed with or without separat-
`as claimed in claim 4, wherein said filter has a plurality
`ing the defective TFT’s from data bus and/or display
`of lines formed of said first, second and third filter ele-
`electrode by a trimming technique such as a laser beam 65 ments, a repetition cycle of said first, second and third
`trimming.
`filter elements in every other lines being two of said first
`filter elements, two of said second filter elements and
`The present invention provides an active-matrix liq-
`uid crystal color display panel in which the number of
`two of said third filter elements arranged in this order
`
`SEC v. Surpass Tech, |PR2015—OO887
`SAMSUNG EX. 1026 — 11/12
`
`SEC v. Surpass Tech, IPR2015-00887
`SAMSUNG EX. 1026 - 11/12
`
`

`
`4,781,438
`
`9
`and a repetition cycle of said first, second and third
`filter elements in the other lines being one of said second
`filter elements, two of said third filter elements, two of
`said first filter elements and one of said second filter
`elements arranged in this order.
`7. An active-matrix liquid crystal color display panel
`comprising lines of color pixel elements, each of said
`color pixel elements including first, second and third
`types of cell elements, each cell element having two
`display electrodes driven by scanning pulses supplied
`through two first buses, said first, second and third
`types of cel