Europfiisches Patentamt
`
`European Patent Office
`Office européen des brevets
`
`CD Publication number:
`
`.
`
`O
`
`EUROPEAN PATENT APPLICATION
`
`63 Application number: 87100148.3
`
`'
`
`.
`
`® Int. Cl‘: G09G 3/36 , GOQG 3/20
`
`@ Applicant: HOSIDEN ELECTROMCS CO., LTD.
`4-33, Kitakyuhoii 1-chome
`Yao-shi 0saka(JP)
`
`® inventor: Yasui, Masaru
`1-8-11, Matsuyama-cho
`Yao-shi Osaka(dP)
`
`Representative: Lehn, Werner, Dipl.-lng. et al
`Hoffmann, Eitle & Partner Patentanwalte
`Arabellastrasse 4
`
`D-80,00 Mtinchen 81(DE)
`
`@ Date of filing: 08.01.87
`
`Date of publication of application:
`13.07.88 Bulletin 88/28
`
`Designated Contracting States:
`AT BE CH DE ES FR GB GR IT LI LU -NL SE
`
`@ Planar display device.
`
`@ A planar display device is disclosed. which com-
`prises a plurality of display elements (12r,3n)
`in
`rows and columns. row drive lines (221) each com-
`monly connected to two adjacent rows of display
`elements and column drive lines (33,._, 3-3,,.i) pro-
`vided in pairs each for each column of display
`elements every other ones of the display elements
`in the column being connected to one of the pair
`column drive lines, the other display elements in the
`column being connected to the other column drive
`lines in the pair. Each of the display elements is
`selectively activated by the row and column drive
`lines connected thereto.
`
`EP0273995A1
`
`'1-zieianoa
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`42z+i.3no5
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`Xerox Copy Centre
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`‘SEC v. Surpass Tech, |PR2015—OO887
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`0 273 995
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`PLANAR DISPLAY DEVICE
`
`BACKGROUND Q ‘rm-i_E INVENTION
`
`This invention relates to a planar display de-
`vice for displaying a monochromatic or color image
`as liquid crystal display, plasma display, light-emit-
`ting diode display, etc. with a plurality of display
`elements arranged in rows and columns.
`As the prior art, a color liquid crystal display
`device will be described to point out problems in
`this type of planar display device.
`Referring to Fig. 1,
`there is shown a liquid
`crystal display device, which comprises a pair of
`transparent sunbstrates 11 and 12 and liquid cry-
`stal 13 sealed therebetween. A plurality of tran-
`parent square display electrodes 1{_n(1 = 1, 2, 3,
`no , n = 1, 2, 3, no ) are provided on the inner
`surface of one of the transparent substrates,
`i.e..
`substrate 11. A transparent common electrode 14
`is provided on the entire inner surface of the other
`substrate 12.
`
`The display electrodes 113 are arranged in
`rows and columns. As shown in Fig. 2, a row drive
`line 21 is provided along corresponding one of
`rows of display electrodes 11,.-i, and a column
`drive line 3,,
`is provided along corresponding one
`of columns of display electrodes 1r,n. A thin-film
`transistor 41,nis provided for each display elec-
`trode 1r__n. Each thin-film transistor 4-1_nhaS a drain
`connected to the corresponding display electrode
`1i,n, a gate connected to the‘ corresponding row
`drive line Zzand a source connected to the cor-
`responding column drive line 3”. Thus, when one
`row drive line 21 and one column drive line 3,, are
`selectively drive, only the thin-film transistor 11,;-1
`connected to these row and column lines is turned
`
`i.e., rendered conductive. The corresponding
`on,
`display electrode 11;.
`is thus connected to the
`column drive line 3,,, and a voltage is applied
`between the display electrode 1”; and the com-
`mon electrode 14 (Fig. 1). The pertaining portion of
`the liquid crystal 13 thus is controlled so that it is
`rendered to have different light transmission char-
`acteristics from those of
`the rest of
`the liquid
`crystal.
`in this manner, voltage is selectively ap-
`plied
`to
`the
`plurality
`of display
`electrodes
`1j,naccording to an image to be displayed, where-
`by a monochromatic pixel display is obtained. Each
`of the display electrodes 11,” corresponding one
`of the thin-film‘ transistors‘ 41,n, corresponding por-
`tion of liquid crystal 13 and common electrode 14
`constitute. in all, one of display elements 5'_1,n.
`For the color display, a red filter R, a green
`filter G and a blue filter B are provided on either
`
`respective display electrodes 11,n or on the cor-
`
`T
`
`responding portions of the common electrode 14.
`These color filters are arranged substantially uni-
`formly,
`for
`instance as shown in Fig. 3. Various
`colors can be displayed as mixtures of the red.
`green and blue colors depending on_ the state of
`display by the plurality of display elements cor-
`responding to the respective display electrodes.
`Hereinunder,
`the display elements for displaying
`the red color will be referred to as R, the display
`elements for displaying the green color as G, and
`the display elements for displaying the blue color
`as B.
`
`(i.e., a
`For displaying a white picture point
`white dot) on the planar color display device, three
`display elements, i.e.. red, green and blue display
`elements. adjacent
`to one another, have to be
`driven simultaneously for white color emission.
`White horizontal and vertical lines can be displayed
`simply by activating corresponding row and column,
`of display elements R, G and B. A 45-degree white
`oblique line from the right top to the left bottom of
`the display device can also be displayed by selec-
`tively activating display elements R, G and B along
`the oblique line, as shown in Fig. 4. However, when
`display elements are selected along a 45—degree
`oblique line from the left top to the right bottom on
`-the display device, only one of the three colors,
`e.g. red display elements R are displayed and a
`white line can not be display, as shown in Fig. 5.
`This problem arises if
`it
`is intended to have one
`picture element (i.e., pixel) constituted by one dis-
`play element.
`i.e.,
`if each display element is in-
`tended to be used as a resolvable picture element
`so that a thin oblique or curved display line can be
`achieved.
`
`is desired to adopt a
`it
`From this standpoint,
`three-color display element set for a picture dot, in
`which a set of three adjacent color display ele-
`ments,
`i.e. red, green and blue color display ele-
`ments R, G and B, are simultaneously driven for
`display of a white picture point, and also any other
`desired color is displayed as a picture point (i.e.,
`dot) of a resultant color of suitable combination of
`light intensities through the three color display.ele-
`ments. To this end, one may occur to consider of
`forming sets of color display elements using each
`two adjacent rows of color display elements as
`shown in Fig. 6. More specifically,
`it can be ar-
`ranged to have adjacent red. green and blue dis-
`play elements R, G and B in two adjacent element
`rows as a set, as shown in Fig. 6,
`thus defining
`color display element sets each shown enclosed
`by a phantom line, these sets constituting respec-
`tive picture points P,_ j(i = 1, 2, 3, no ,j = 1, 2, 3.
`000)
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`For the display on the planar display device.‘
`one row drive line 21 is selectively driven via a row
`drive circuit 17 according to the contents of a row
`register 16. while one column drive line 3,, is selec-
`tively driven via acolumn drive circuit 19 according
`to the contents ‘of a column register 18. as shown
`in Fig. 2, thus causing the display of a correspond-
`ing display electrode.
`in the column register 18.
`image signal data for one display line is stored in
`correspondence to
`individual display elements
`5r,nof the display line. After the display of this line,
`the next row drive line is selectively driven, and
`image signal data for the next line of display ele-
`ment row to be displayed is stored in the column
`register 18. Likewise, successive row drive lines
`are selectively driven while storing image signal
`data for a line in the column register 18 after
`selection of each row drive line.
`
`For the display through representation by sets
`of three-color display elements as respective pic-
`ture points as shown in Fig. 6 using the system of
`Fig. 2, one display row 6, is displayed as follows.
`As the image signal, three color signals Rk, Gk and
`B.. (k = 1. 2, 3, no ) for each picture point (i.e.,
`dot) are supplied as parallel signals, as shown in
`Fig. 7. The individual picture point signals in the
`signals for one display row are divided into two
`signals,
`i.e., one being a stream of R1, 31, C2. R3,
`Ba. G4, on loaded in the column register 18 as
`shown in Fig. 8A and the other being a stream of
`G1, R2, B2. G3. R4. B4. on as shown in Fig. 8B.
`First,
`the signal shown in Fig. 8A stored in the
`column register 18 in Fig. 2 is provided to activate
`the display elements connected to the correspond-
`ing row drive line 21 and individual column drive
`lines 3,,, 3.,.,, 2,,.2, no . Then, the signal shown in
`Fig. 8B stored in the column register 18 is provided
`to activate the display elements connected to the
`row drive line 21 +1.
`In the above way. the display
`signal for one display row (i.e., one horizontal scan-
`ning line cycle)
`is divided into two signals for
`driving display elements independently. Therefore,
`the operation is complicated. Besides, since the
`image signal
`is usually supplied for each display
`row.
`i.e., each horizontal scanning line, the afore-
`mentioned display system, therefore,
`is inferior in
`view of the matching with the divided two streams
`of input image signals.
`Furthermore,
`in the planar display device the
`display surface is repeatedly scanned by selecting
`successsive row drive lines.
`it the repetition cycle
`period of scanning the display area (i.e., vertical
`cycle period),
`i.e., one frame display period.
`is
`long, flicker of the display surface screen occurs to
`deteriorate the quality of display. For this reason. it
`is difficult
`to set the vertical cycle period to be
`longer than about 1/50. second. Since the vertical
`cycle period is fixed, by increasing the row drive
`
`lines the period of driving one row drive line is
`reduced. Therefore, this leads to a problem in case
`of a liquid crystal display drive in that display
`electrodes fail
`to be charged sufficiently. That is.
`there is an‘ upper limit on the number of row drive
`lines, and the resolution can not be improved be-
`yond this limit. Even in case of a display device
`having high response speed compared to the liquid
`crystal display device,
`increasing the row drive
`lines dictates increase in the rate of switching of
`the tow drive lines, thus leading to expensive and
`complicated peripheral circuits.
`
`'
`
`SUMMARY 9'; THE INVENTION
`
`It is an object of the present invention to pro-
`vide a planar display device which is capable of
`displaying a picture of graphic pattern with high
`quality..
`According to the invention, row drive lines are
`each provided for
`two adjacent
`rows of display
`elements. That is. the display elements in the two
`rows are connected to the common row drive line.
`
`Column drive lines are provided in pairs each for
`each column of display elements. Every other ones
`of the display elements in the column are con-
`nected to one of the pair column drive lines, and
`the other display elements in the column are con-
`nected to the other column drive lines in the pair.
`Each of
`the display elements is selectively dis-
`played by the row and column drive lines con-
`nected to it.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`in a
`is a sectional view showing,
`1
`Fig.
`simplified form. the general construction of a liquid
`’ crystal display device;
`Fig. 2 is a view showing the relation among
`display electrodes, drive lines and thin-film transis-
`tors of a prior art liquid crystal display device.
`Fig. 3 is a view showing an example of
`arrangement of color
`filters in the liquid crystal
`display device:
`Fig. 4 is a view showing a 45° display line of
`an array of display elements extending upper right
`to lower left;
`
`Fig. 5 is a view showing a 45° display line of
`an array of display elements extending upper left
`to lower right;
`Fig. 6 is a view showing an example of
`display as three-color display-element sets as pic-
`ture dots;
`
`Fig. 7 is a view showing an example of
`image signal train:
`
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`Figs. 8A and 8B show streams of divided
`image signal stored in the column register 18 for
`activation of
`three-color display-element sets as
`respective picture dots on the prior art display
`device shown in Fig. 2;
`--
`Fig. 9 is a view showing the relation among
`display electrodes,’ column drive lines.
`row drive
`lines and thin-film transistors in case where a
`
`planar display device according to the invention is
`applied to the liquid crystal display;
`Figs 10A, 10B and 10C show an example of
`a color image signal stored in the column register
`18 shown in Fig. 9;
`Fig. 11 is a view similar to Fig. 9 but show-
`ing a second embodiment of the invention;
`Fig. 12 is a view showing a different example
`
`to the
`
`of a circuit for supplying an image signal
`display device according to the invention;
`Fig. 13 is a view showing an example of
`interlaced scanning in the second embodiment;
`Hg. 14 is a view showing the relation among
`a liquid crystal AC drive signal, each field and
`column and row drive lines; and
`
`Fig. 15 is a _view showing an example of
`circuit for producing the AC drive waveform shown
`in Fig. 14.
`
`DETAILED DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`Now, an embodiment of the invention applied
`to a liquid crystal planar display device will be
`described. The embodiment employs the ‘structure
`shown in Fig. 1. However, the embodiment is dif-
`ferent from the prior art system in the arrangement
`and interconnection of the display electrodes and
`row and column drive lines. Fig. 9 is a view similar
`to Fig. 2 but shows the embodiment of the inven-
`tion. ' Referring
`to
`Fig.
`9, display electrodes
`121,3nare arranged in rows and columns. Unlike
`the prior art system, row drive lines 22; are each
`provided for
`two adjacent
`rows of display elec-
`trodes 121,311.
`In the illustrated example, one row
`of display electrodes 121,3,-., 1g1,3n-4-2,... is pro-
`vided above the row drive line 221, and the other
`row of display electrodes 121,3n+1, 1g1,3n+3,
`no is provided below the line. Two column drive
`lines are provided for each column of display elec-
`trodes. For example, column drive lines 33,, and
`33,.” are provided on the opposite sides of the
`
`_ column of display electrodes 1g1,3n, 12g,3n+1,
`O00 .
`
`Thin-film transistors 421,311 are each provided
`for each of the display electrtodes 121,311. To the
`row drive line 22'; are connected the gates of thin-
`film transistors corresponding to the display elec-
`trodes, between which the drive line 221 extends.
`
`The display electrodes in each column are con-
`nected alternately and through the respective thin-
`film transistors to the column drive lines on the
`opposite sides of
`the column. For example,
`the
`display electrodes 1g1,3n, 131 +2,3n are connected
`through the respective thin-film transistors 421_3n,
`421 +2,3n, on to the column line 33“, and the
`display electrodes 121,3n+1, 121 +2,3n+1, on
`are connected through the respective thin-film tran-
`sistors 42i_3n +1, 421 +2,3n+1, on to the column
`drive line 33"”. Again in this structure, each dis-
`play electrode constitutes together with the cor-
`responding thin-film transistor and corresponding
`portions of the liquid crystal and common electrode
`(Fig. 1) a display element 5.
`_
`In the case of the color display, red, green and
`blue color filters R, G and B are provided substan-
`tially in a uniform arrangement in correspondence
`to the individual pixel electrodes.
`In this construction,
`the red, green and blue
`colour signals Rk, Gk and Bk or color image signal
`supplied through input lines 25Fl, 25G and 258 -are
`supplied through a color signal switching circuit 26
`to color signal buses 27 to 29. A horizontal sync
`pulse signal l-{syn of the color image signal is sup-
`plied from a horizontal sync input terminal 31 to a
`tertiary counter 32. The color signal switching cir-
`cuit 26 is controlled to switch the color signals
`according to the count of the tertiary counter 32.
`According to the control the color signal switching
`circuit 26 connects the input signal lines 25R, 25G
`and 25B to the color signal buses 27, 28 and 29 ,
`or 28, 29 and 27. or 29. 27 and 28, respectively.
`The color signal buses 27 to 29 are repeatedly
`connected to successive stages of the column reg-
`ister 18, and the outputs of these stages drive the
`column drive lines 33“, 33,..1, 33,,.2, 33,,.3. 33,,.4,
`33.,+5, on through the column drive circuit 19. A
`clock signal having three times the dot frequency
`of the input color image signal is supplied as shift
`clock from a clock terminal 33 to a shift register 34,
`and a horizontal sync pulse is supplied from the
`terminal 31 to the first stage of the shift register 34
`at the start of each horizontal scanning cycle pe-
`riod. Data from the individual stages of the column
`register 18 are fetched successively in response to
`the outputs of the respective shift stages of the
`shift register 34.
`Thus, when red, green and blue color signals
`Bk, Gk and Bk are stored as the image signal of a
`certain horizontal cycle period in the manner as
`shown in Fig. 10A in the column register 18 and
`the row drive line 22;; is driven at this time. all the
`display elements (i.e., display electrodes) in the
`two rows associated with the row drive line 221
`
`shown in Fig.. 9 are driven according to the con-
`tents of the corresponding stages of the column
`register 18. Thus,
`the three-color display-element
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`sets of respective picture are simultaneously driven
`for one display row.
`
`In the next horizontal cycle, color signals are
`stored in the manner as shown in Fig. 10B in the
`column register 18, and the row drive line 221 +2 is
`driven. Thus, the display elements associated with
`the row drive line 221 +2 shown in Fig. 9 are driven
`likewise as simultaneous drive for one display row.
`in the further horizontal cycle, color signals are
`stored in the manner as shown in Fig. 10C in the
`column register 18. and the row drive line 221 +4 is
`driven. Thus. the display elements associated with
`the row drive line 2214-4 are driven as simulta-
`neous drive for one display row. The image signal
`is stored successively and repeatedly in the order
`of Figs.
`10A to 10C for
`respective horizontal
`periods in the column register 18.
`It is possible to
`arrange such that the color signals on the color
`signal buses 27 to 29 are stored simultaneously in
`three stages of the column register 18 for each dot
`of the input image signal.
`Fig. 11 shows a second embodiment of the
`invention. In the preceding first embodiment of Fig.
`9, each row drive line 221
`is provided for every
`two rows of display elements.
`In this second em-
`bodiment. however. each row drive line is provided
`for each display element
`row. That
`is,
`row drive
`lines 221+1, 221 +3, on are provided additionally
`to the embodiment of Fig. 9. To each of these
`additional
`row drive lines are connected display
`elements on the opposite sides,
`i.e., on the upper
`and lower sides of the additional row drive line in
`
`the Figure. Each display element is also connected
`to the column drive lines or opposite sides thereof.
`in more specific,
`there are provided, on opposite
`
`sides of the row drive line, for example,V2g1+1,
`additional
`thin-film transistors (labeled by circles)-.
`42t+1,3n. 42t+1,3n+2. 0-0 . and 42t+1,3n+1.
`4g[+1,3n+3,uo on one sides of the respective
`display electrodes 12g,3n+1, 12!H3n+3, on , and
`22z+2,3n, 12z+2,3n+2, no , opposite respec-
`tively from those thin-film transistors 421,3n+1,
`42t,3n +3. --0 and 42t+2,3n. 42li+2,3n+2. "-
`shown in Fig. 9. These additional thin-film transis-
`tors on opposite sides of the additional row drive
`line 221, +1 have gates connected to the row drive
`line 221, + 1, drains connected to the corresponding
`display electrodes and sources connected to the
`corresponding column drive lines on the sides of
`the respective display electrodes opposite from
`those column drive lines connected to the thin-film
`transistors having no circle label. That is, the thin-
`film transistors 421 +1,3n, 421 +1,3n+g, no , and
`42[+1,3n+1, coo .421-l~1,3n+3, one have their
`drains connected to the respective opposite side
`display electrodes 1gi_3n+1, 12i,3n+3, no and
`121 +2,3n, 12i+2,3n+2, on . their sources con-
`nected to the respective column drive lines 33...
`
`33,,.g, poo . and 33,..1, 33,,.3, on and their gates
`commonly connected to the row drive line 221, +1.
`in a similar manner, additional
`thin-film transistors
`
`are provided for each ‘of the other additional
`' drive lines.
`
`row
`
`In either first or second embodiment, two rows,
`i.e., upper and lower side rows of display elements
`are connected to each row drive line, so that two
`
`rows of display elements can be displayed while a
`single row drive line is being selected. Thus, the
`row drive lines can be reduced in number to one
`
`hald compared to the row drive lines in the prior art
`arrangement shown in Fig. 2. This means that for
`the same period, during which each row drive line
`is selectively driven,
`the driving period for one
`frame can be reduced to one half,
`resulting in
`reduced flicker and improved quality of the dis-
`played image. Alternatively,
`for
`the same frame
`display period, e.g., 1/60 second,
`the number of
`display element rows can be doubled to increase
`the resolution correspondingly. Further,
`for
`the
`same number of display element rows, the period
`of driving of one row drive line can be doubled
`compared to the prior art system. That is, the drive
`speed can be reduced to permit simpler construc-
`tion of the peripheral circuits. Further,
`in the case
`of the liquid crystal display. the charging period for
`each of the display electrodes can be extended so
`that it is possible to obtain a display image having
`an improved contrast.
`Although the number of column drive lines is
`doubled compared to the prior art system,
`the
`number of row drive lines is reduced to one half, so
`
`that the design and manufacture of the device will
`not become difficult.
`
`Where the prior art planar display device is
`used for the color display of the type where each
`picture point is represented by a set of three color
`display, elements,
`the row drive line has to be
`driven twice for the display of one display row.
`In
`other words, the display device is scanned twice
`during one horizontal scanning cycle period of the
`image signal. Therefore, the correspondency to the
`image signal is unsatisfactory in view of displaying
`the image signal supplied for each horizontal scan-
`ning cycle period. According to the invention, the
`image signal supplied for each horizontal scanning
`cycle period is displayed by driving each row drive
`line only once for one horizontal scanning line
`period. Nevertheless, the display thus obtained for
`one display row consists of three-color display ele-
`ment sets as respective picture points. The display
`device according to the invention thus has satisfac-
`tory matching property with respect to the input of
`the image signal.
`.
`According to the invention. three color signals
`for each picture point can be simultaneously input
`to the column register 18 as mentioned earlier.
`
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`10
`
`is possible to store three color signals
`it
`Further.
`for two or three picture points simultaneously in the
`column register 18.
`For example, as shown in Fig. 12, it is possible
`that the color signal buses 27 to 29 are connected
`through a one-dot delay circuit 35 to color‘ signal
`buses 36 to 38. and the color signals 27 to 29 and
`36 to 38 are successsively and repeatedly con-
`nected to individual stages of the column register
`18.
`in this case, the column register 18 is divided
`into groups each consisting of 6 stages, a horizon-
`tal sync pulse H5,“ is supplied to the first stage of a
`shift
`register 239 and shifted therethrough in re-
`sponse to the output of a frequency divider 41,
`which divides the frequency of a dot clock from a
`
`terminal 40 to one half, and writing of_ data in one
`of the groups of the column register 18 is effected
`according to the output of each stage of the shift
`register 39.
`In this way, the input image signal
`is
`stored six color signals for two picture dots at a
`time in the column register 18.
`With the second embodiment shown in Fig. 11,
`it is possible to display one field, say, even field by
`three-color display-element sets for respective pic-
`ture dots as shown by solid lines in Fig. 13 using
`the row drive lines 221, 2214-2, no -and then
`
`‘display one field, say, odd field by three-color
`display-element sets for respective picture dots as
`shown by phantom lines using the row drive lines
`221+1, 221 +3, on . By repeating the alternate
`displays shown by the solid and phantom lines in
`Fig. 13,
`it
`is possible to obtain a display well
`matched to the interlaced scanning image signal
`and also improve the resolution in the direction of
`the column drive lines.
`
`Further,
`
`in the second embodiment
`
`twofold
`
`path is provided for the driving of each display
`element. That is, even if one of the two paths is
`defective,
`the display element may be driven
`through the other path. This means a correspond-
`ing increase in the production yield. While the
`above embodiments of
`the invention have con-
`
`cerned with the liquid crystal planar display de-
`vices, the invention is applicable to planar display
`devices based on light-emitting diodes or plasma
`display as well.
`longer
`As for the driving of the liquid crystal,
`life can be ensured by AC driving. From this stand-
`point,
`it may be possible to adopt in the second
`embodiment (Fig. 11) to drive the liquid crystal with
`positive voltage for
`the column drive lines 33“,
`33,,..2, 32.,.,4 uoand with negative voltage for the
`column drive lines 33,,.1, 32,,.3, 33,,,5, no‘. How-
`ever, when a certain column drive line 32,.
`is dis-
`
`connected, the portion of liquid crystal correspond-
`ing to display elements each connected to both the
`column drive lines 33,,and 32..., on the side beyond
`the point of disconnection opposite from the power
`
`is driven solely by the positive voltage
`supply,
`through the column drive line 33... The life of this
`portion of liquid crystal would be thus shortened.
`This drawback can~be overcome by a driving -
`scheme shown‘ in Fig. 14. Let
`it be taken as an‘
`example of the display electrode 121,3n+1 con-
`nected via thin-film transistors to the column drive
`
`lines 32,. and San-v-1 simultaneously driven by either
`positive or negative volatage. For the first field (odd
`field) the row drive line 221 +1 is selected to turn
`ON the thin-film transistor 421-r-1,3n, whereby a
`negative voltage is applied across the liquid crystal
`at the display electrode 121,3n +1 by negative volt-
`age supplied from the line 33“, for the second field
`(even field) the row drive line 221 is selected to
`turn ON the transistor 421,3n+1, whereby a nega-
`tive voltage is applied across the liquid crystal at
`the same display electrode by negative voltage
`supplied from the line 33.,..1, for the third field (odd
`field) the line 221+1 is selected to turn ON.the
`transistor 421 +1,3n. whereby a positive voltage is
`applied across the liquid crystal by positive voltage
`supplied from the line 33“, and for the fourth field
`(even field)
`the line 221 is selected, whereby a
`negative voltage is applied across the liquid crystal
`by negative voltage supplied from the line 32".,
`For the subsequent fields, the drive control is car-
`ried out as shown in Fig. 14. As will be seen from
`Fig. 14, the drive control sequence pattern repeats
`for every eight successive fields. The pattern
`shown in Fig. 14 is only an example of driving
`waveform, and it is also possible to use a pattern
`which is shifted in phase by one field period with
`respect to the pattern of Fig. 14. When applying a
`positive or negative voltage to the column drive
`lines, zero voltage is applied to the common elec-
`trode 4 (Fig. 1).
`ir-
`the liquid crystal
`For
`the AC driving of
`respective of the disconnection of a row drive line,
`the following procedure is effective. Taking the row
`drive lines 221 and 221 +1 as an example, for the
`first field, during which the row drive line 221 +1 is
`driven, a negative volatage is applied across the
`liquid crystal at the respective display electrodes
`supplied from all the selected column drive lines.
`for the second field, during which the row drive line
`221 is driven, negative voltage is supplied to all the
`selected column drive lines,
`for
`the third field.
`
`is driven
`during which the row drive line 221 +1,
`positive voltage is supplied to all the selected col-
`umn drive lines. and for the fourth field negative
`voltage is supplied to all the selected column drive
`lines.
`1
`The waveform as shown in Fig. 14 may be
`obtained with an arrangement as shown in Fig. 15.
`for
`instance. The vertical sync pulse signal sup-
`
`plied from a terminal 51 is frequency divided into
`one half the frequency in a flip-flop 52. The 0
`
`SEC v. Surpass Tech, |PR2015—OO887
`SAMSUNG EX. 1031 — 6/16
`
`SEC v. Surpass Tech, IPR2015-00887
`SAMSUNG EX. 1031 - 6/16
`
`

`
`11
`
`_
`
`0273 995
`
`A
`
`.
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`12
`
`and Q outputs of the flip-flop 52 are used to control
`gates 53 and 54 to separate the input vertical sync
`pulses into even and odd field pulses. The sepa-
`rated pulse signals are frequency divided into one
`half the frequency in respective flip-flops 55 and
`56. The outputs of these flip-flops are ANDed in an
`AND gate 57. Meanwhile, the output of the flip-flop
`56 is frequency divided into one half the frequency
`in a flip-flop 58. The outputs of the flip-flop 58 and
`AND gate 57 are exclusively OFled in an exclusive
`OR gate 59. As a result. an intended output
`is
`obtained at an output terminal 61.
`
`Claims
`
`A planar display device comprising a plurality
`of display elements (121_3n) arranged in rows and
`columns, a plurality of first row drive lines (221)
`provided for and extending along respective rows
`of said display elements and a plurality of column
`drive lines (33,.,) provided for and extending along
`respective columns of said display elements, said
`first row drive lines and column drive lines being
`selectively driven to selectively activate said dis-
`play elements.
`
`CHARACTERIZED IN THAT
`said first row drive lines each are provided for two
`adjacent rows of said display elements, said dis-
`play elements on opposite sides of each said first
`row drive line (221) being commonly connected to
`said first row drive line, said column drive lines
`
`being provided in pairs (33,,, 33,,,1) each for each
`column of said display elements, every other ones
`of said display elements in
`said column being
`connected to one of said pair column drive lines,
`the other display elements in_ said column being
`connected to the other column drive line in the
`. pair.
`
`2.The planar display device according to claim
`1, which further comprises second row drive lines
`
`each provided for and extending between two adja-
`cent display element rows between adjacent said
`first
`row drive lines. corresponding ones of said
`display elements on opposite sides of each said
`second row drive line being commonly connected
`to said each second row drive line, each of said
`
`display elements in each column being connected
`to both said column drive lines in the pair for the
`corresponding column of said display elements.
`3. The planar display device according to claim
`1, which further comprises row drive means for
`driving said plurality of first
`row drive lines one
`.after another
`in synchronism with the horizontal
`scanning cycle of an_ image signal to be displayed
`and column drive means supplied with said image
`signal
`for one scanning lines and having stages
`
`in number to said plurality of column drive
`equal
`lines for driving s_aid. column drive lines according
`to the outputs of corresponding said stages.
`' 4. The planar display device according to claim
`2 or 3, wherein red, green and blue color filters are
`provided on respective said display elements to
`form three-color display element sets such that
`said color filters are substantially uniformly distrib-
`uted as a whole,
`two of the three color display
`elements in each set
`in a column and the other
`color display element in an adjacent column con-
`stituting one of picture points with respect to a first
`row drive line.
`
`5. The planar display device according to claim
`4, wherein said input image signal consists of serial
`pixel signals each consisting of parallel, red, green
`and blue color signals, and said device further
`comprises a shift register supplied with the hori-
`zontal sync signal for shifting signals under control
`of a clock signal at thr