(12) INTERNATIONAL APPLICATION PlJBLISHED lJNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property Organization
`lntcnrntional Bureau
`
`I IIIII IIIIIIII II IIIIII IIIII IIII I II Ill lllll lllll lllll lllll lllll llll 1111111111111111111
`
`(43) International Publication Date
`25 September 2003 (25.09.2003)
`
`PCT
`
`(10) International Publication Number
`WO 03/079442 Al
`
`(51) International Patent Classification 7:
`
`BOIL 27/00
`
`(21) International Application Number:
`
`PCT/lB03/00999
`
`[GB/GB]: c/o Prof. IIolslluan 6. NL-5656 AA Eindhovcn
`(NL J. CHILDS, Mark, J. l GB/GB J; c/o Prof. Holsllaan 6.
`NL-5656 AA EindhoYen (NLJ.
`
`(22) International Filing Date: 19 March 2003 (19.03.2003)
`
`(25) Filing Language:
`
`(26) Publication Language:
`
`English
`
`English
`
`(30) Priority Data:
`0206551.4
`0209557.8
`0216053.9
`
`20 March 2002 (20.03.2002) GB
`cm
`26 April 2002 (26.04.2002)
`11 July 2002 (11.07 2002) GB
`
`(71) Applicant Uor all designated Stutes except CS): KONIN(cid:173)
`KLIJKE PHILIPS ELECTRONICS N.V.
`lNL/NLJ:
`Groenewoudseweg 1, NL-5621 HA Hindhoven (NL).
`
`(72) Inventors; and
`(75) Inventors/Applicants Cfur US unly): HECTOR, Jason,
`R. lGB/GBJ; c/o Prof. Holstlaan 6, NL-5656 AA Eind(cid:173)
`hoven (NL). YOUNG, Nigel, D. IGB/GBI: c/o Prof. Hol(cid:173)
`stlaan 6, NT.-5656 AA Rindhoven (Nla). FISH, David, A.
`
`(7.t) Agent: WHITE, Andrew, G.; Intcrnationaal Octrooibu(cid:173)
`llolsllaan 6, NL-5656 AA Uindhmen
`reau B.V., Prof.
`(NL).
`
`(81) Designated States (national): AE, AG, AL, i\T\f, AT. AU.
`AZ, BA, BB, BG. BR, BY, BZ, CA. CII, CN, CO, CR, CU.
`CZ, DU, DK, DM, DZ, EC. EU, US, n, GB, GD, GE. GIL
`GM. HR. HU, ID. IL, IN. 15, JP, KE, KG. KP, KR, KZ, LC.
`LK, LR, LS, IT, LU, LV, MA, MD, MG, MK, MN, MW.
`MX. MZ. NT, NO, NZ. OM. PH. PL, PT. RO. RU, SC, SD.
`sn, SG, SK, SL. T.T, TM, TN, TR. TT, TZ, UA, UG, US.
`UZ, VC, VN, YU, ZA, ZM, ZW.
`
`(8.t) Designated States (regional): ARIPO patent (GH. GM.
`KE, LS, l'vfW. MZ, SD, SL SZ. TZ. UG, ZM, ZW).
`Eurasian patent (AM, AZ, BY. KG. KZ, MD, RlT, T.L TM).
`European patent (AT, BE, BG. CII. CY, CZ, DE, DK, EE
`ES, Fl. FR. GB, GR, HU, IE. IT, LU, MC, NL, PT. RO.
`SE, SL SK. TR). OAPl patent (Br'. BJ, CF, CG, CL CM.
`GA. GN. GQ, GW, ML, MR, NE, SN. TD. TG).
`
`[Continued on next page]
`
`(5.t) Title: ACTIVE MATRIX ELECTROLUMINESCENT DISPLAY DEVICES, AND THEIR MANUFACTURE
`
`230(23)
`
`,J .
`
`= -!!!!!!!! --= !!!!!!!!
`!!!!!!!! ---
`= --------------------------------------------
`-= !!!!!!!! = -
`== --= ----= -
`
`210
`~
`40
`240
`
`210
`~
`40
`240
`
`200
`
`231
`22
`25 (LED)
`
`2
`11
`
`250
`
`140
`
`250
`
`M (57) Abstract: Physical barriers (210) are present between neighbouring pixels (200) on a circuit substrate (100) of an active-ma(cid:173)
`"'1" trix electroluminescent display device, particularly with LEDs (25) of organic semiconductor materials. The invention forms these
`"'1" barriers (210) with metal or other electrically-conductive material (240), that is insulated (40) from the LEDs but connected to the
`~ circuitry within the substrate ( 100). This conductive barrier material (240) backs-up or replaces at least a part of the drive supply line
`
`...._ age drop from within the circuit substrate (100), where it is severely constrained, to the much freer environment of the pixel barriers
`
`be made with low voltage drops along this composite drive supply line (140,240). Furthermore, the structure can be optimised to
`
`= (140,240) to which the LEDs are connected by a drive element Tl. This transfers the problem of line resistance and associated volt(cid:173)
`a (210) on the substrate (100) where the conductive barrier material (240) can provide much lower resistance. Very large displays can
`0 form a smoothing capacitor (Cs) between this drive supply line (140,240) with its conductive barrier material (240) and the further
`
`:;, supply line (230) of the LED upper electrodes (23) extending on an insulating coating (40) over the top of the conductive barrier
`;;, material (240).
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 001
`
`

`

`WO 03/07944 2 A 1
`
`I IIIII IIIIIIII II IIIIII IIIIIIIII I II Ill lllll lllll lllll lllll lllll llll 1111111111111111111
`
`Published:
`-
`with international search report
`
`For two-letter codes and other abbreviations, rejer to the "Guid(cid:173)
`ance Notes on Codes and Abbreviations" appearinR at the be;;in(cid:173)
`nin;; of each regular issue of the PCT Gazette.
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 002
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`1
`
`DESCRIPTION
`
`5
`
`10
`
`1s
`
`20
`
`ACTIVE MATRIX ELECTROLUMINESCENT DISPLAY DEVICES, AND
`
`THEIR MANUFACTURE.
`
`This
`
`invention relates
`
`to active-matrix electroluminescent display
`
`devices, particularly but not exclusively using
`light-~mitting diodes of
`semiconducting conjugated polymer or other organic semi,conductor materials.
`The invention also relates to m~thods of manufacturing suiph devices.
`
`Such active-matrix electroluminescent displayi:I ~evic~'s I are known,
`comprising an array of pixels that is present on a circui~ substrate, wherein
`each pixel comprises a current-driven electroluminescent element, typically of
`organic semiconductor material.
`In many such arrays, physical barriers of insulating material are present
`between neighbouring pixels in at least one direction of the array. Examples
`
`of such barriers are given in published United Kingdom patent application
`GB-A-2 347 017, published PCT patent application WO-A1-99/43031,
`published European patent applications EP-A-0 895 219, EP-A-1096568, and
`EP-A-1 102 317, the whole contents of which are herebY: incorporated herein
`as reference material.
`Such barriers are sometimes termed "walls", "partit1ons'1, "banks", "ribs",
`
`"separators", or "dams", for example. As can be 3ieen from the cited
`TIJ~Y mc;1y I be used in
`references, they may serve several functions.
`2s manufacture to define electroluminescent layers and/or e\ectrode layers of the
`individual pixels and/or of columns of pixels. Thus, for example, the barriers
`prevent pixel overflow of conjugate polymer materials that may be ink-jet
`printed for red, green and blue pixels of a colour display or spin-coated for a
`
`monochrome di'splay. The barriers in the manufactured device can provide a
`30 well-defined optical separation of pixels. They may also carry or comprise
`(such
`as
`upper electrode material
`of
`the
`conductive material
`electroluminescent element), as auxiliary wiring for reducing the resistance of
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 003
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`2
`
`(and hence the voltage drops across) the common upper electrode of the
`
`electroluminescent elements.
`
`Each electroluminescent element of an active-matrix display device is
`
`connected in series with a drive element (typically a thin-film transistor,
`
`5
`
`hereafter termed "TFT") between two voltage supply lines of the array. These·
`two supply lines are typically a power supply line and a g:round line (also
`termed "return line'l Light emission. from the electro1:uminescent element,
`
`typically a LED, is controlled by the current flow therethrough, as altered by its
`.....
`respective drive element TFT. The supply line to which t~e electroluminescent
`
`10
`
`elements are connected by their series drive elements· may be termed the
`
`"drive supply line" or "drive line" or "current drive line" of the pixels. Voltage
`
`drops along these two supply lines can result .in incorrect drive currents for
`
`individual pixels. This can lead to a decrease in emission intensity (i.e. fading
`
`of the image) from pixels in the centre of the display. Indeed, with large-area
`
`15
`
`displays, the effect may be so bad that no emission occurs at the centre, so
`
`limiting the acceptable display size.
`
`Several measures have been proposed in order to reduce such voltage
`
`drops and/or their effects for a row of pixels. Thus, it is known from published
`
`U,nited States patent application US-A 1-2001 /QOQfl 413'
`
`1 (Philips
`
`ref:
`
`20
`
`PHGB000001) to reduce voltage drops along the line by· tapering the width of
`
`the
`
`line.
`
`Published PCT patent applications WO-A 1-01/01383 and
`
`WO-A1-01/01384 (Philips refs: PHB34350 & PHB34351) adopt a different
`
`approach in which error values are generated to correct the drive signals for
`
`each pixel. The whole contents of US-A1-2001/0007413, WO-A1-01/01383
`
`25
`
`and WO-A1-01/01384 are also hereby incorporated herein as reference
`
`material.
`
`It is an aim of the present ·invention to reduce such voltage drops along
`
`the drive supply line, and to do so in a manner that does not significantly
`
`30
`
`complicate the device structure, its layout and its electronics.
`
`According to one aspect of the present invention, there is provided an
`
`active-matrix electroluminescent display device with the :ff:}~tur~s of Claim 1.
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 004
`
`

`

`WO 03/079442
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`PCT /IB03/00999
`
`3
`
`In accordance with the invention, the physical baniiers between pixels
`
`are partly and/or predominantly of electrically-conductive material (typically
`metal) that is insulated from the electroluminescent elements and that provides
`
`at least a part of the drive supply line. This conductive barrier material may
`
`5
`
`form a conductive core of the barrier. It is connected into the circuit substrate,
`
`to electrode connections for the respective drive elements, via contact
`) between the pixel barriers and the drive
`windows (hereinafter termed 11vias 11
`
`elements in the substrate. Thus, the problem of line resistanc~ and associated
`
`voltage drop is transferred from within the circuit substrate (where it is severely
`constrained) to the much freer environment of the pixel barriers oh the
`
`10
`
`substrate (where the conductive barrier material can provide much lower
`resistance).
`
`By this means, the electrical resistance along the drive supply line (and
`consequential voltage drops) can be significantly reduced,: as compared with a
`conductor layer within the circuit substrate, for example a thin-film electrode
`line of the drive element. Thus, along this drive line, the conductive barrier
`
`15
`
`material has a cross-sectional area that is typically larger (for example, at least
`twice as large as, or even at least an order of magnitude larger) than that of a
`
`thin conductor layer in the circuit substrate. As such, the resistance (even of
`long lines) can be low, and very large electroluminescent displays can be
`
`20
`
`constructed in accordance with the invention. Even with smaller displays, the
`
`image quality can be improved by use of the conductive barrier material in
`
`accordance with the present invention.
`By providing one via per pixel, continuous barrier lines of conductive
`
`25 material on the circuit substrate can be used to replace the drive lines that
`
`were previously incorporated within the drcuit substrate. This permits an
`increase in pixel aperture. The conductive barrier line itselfi may simply
`overlap with a column or row conductor line of the array. Alternatively, lines
`
`(or individual lengths) of the conductive barrier material may be used to back-
`
`30
`
`up corresponding lengths of a drive line of the circuit substrate. This
`alternative provides greater choice in the number and location of the vias.
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 005
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`4
`
`The design of such a device structure in accordance with the invention
`
`may also be optimised to include a smoothing capacitor between the two
`voltage supply lines of the electroluminescent element. The insulation of the
`conductive barrier material from the electroluminescent elements can form a
`
`5
`
`capacitor dielectric of this smoothing capacitor. This insulation may be in the
`
`form of a coating on the sides and top of the conductive barrier material.
`
`Typically, the said furl.her supply line (for the upp'.er electrode of the
`
`electroluminescent element) may extend on this insulatin,~ coating over the top
`.._
`of the conductive barrier material. Thus, a smoothing1 c9pacitor for the power
`supply can be readily realized between the drive line that comprises the
`
`10
`
`conductive barrier material and the further supply line ,hat comprises upper
`electrodes of the electroluminescent elements.
`
`It is advantageous for the physical barriers to extend as a network of
`conductive barrier material between pixels in both row and column directions
`
`15
`
`of the array; Such a network of conductive barrier . material can serve to
`It can also
`reduce resistance between drive line areas across the array.
`
`provide a design option in determining the capacitance value of the smoothing
`capacitor for the power supply to the electroluminescent elements.
`
`However, the physical barriers may extend between pixels in just one
`direction of the array, for example in a column or row direction. In this case,
`
`20
`
`additional insulated barriers of conductive barrier, materi~I may be provided in
`th~ transverse direction for a different·purpose, for ex~rt1ple to IJ>ack-up a row
`
`or column line. These additional insulated barrier~ may even be constructed to
`form an additional component, for example a holding cap&citor at each pixel.
`
`25
`
`According to another aspect of the present invention, there are also
`
`provided advantageous methods of manufacturing such an active-matrix
`
`electroluminescent display device in accordance with the first aspect. The
`method may include the steps of:
`
`opening contact windows in the intermediate insulating layer on
`(a)
`the circuit substrate to expose electrode connections for respective drive
`
`30
`
`elements of at least some of the pixels;
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 006
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`5
`
`(b)
`
`forming the physical barriers on the cir~uit substrate with
`
`insulation at least at the sides of the physical barriers a;djacent to the pixel
`areas; and
`
`I
`
`providing the electroluminescent element~ i'n the1
`(c)
`between the physical barriers,
`
`5
`
`· pixel areas in
`
`wherein the conductive barrier material is pro~ided by depositing
`electrically-conductive material at least for connection at the contact windows
`
`of the intermediate insulating layer.
`
`Various processes may advantageously be used to deposit and form
`the barrier material(s) and to insulate the conductive barrier material.
`
`10
`
`Various
`
`advantageous
`
`features
`
`and
`
`feature-combinations
`
`in
`
`accordance with the present invention are set out in the appended Claims.
`These and others are illustrated in embodiments of the invention that are now
`
`I
`
`15
`
`described, by way of example, with
`
`reference
`
`to
`
`the accompanying
`
`diagrammatic drawings, in which:
`
`Figure 1 is a cross-sectional view of part of a pi~el array and circuit
`substrate of an active-matrix electroluminescent displc:1-y device (that has
`
`conductive barriers forming at least part of a drive lin$) as one particular
`embodiment of the invention;
`
`20
`
`Figure 2 is a plan view of four pixel areas (showing a specific example
`
`of layout features for the conductive barriers of such a device in accordance
`with the invention), the cross-section of Figure 1 being taken on the line 1-1 of
`Figure 2;
`
`25
`
`Figure 3 is circuit diagram for four such pixel areas of such a device in
`
`accordance with the invention;
`Figure 4 is a cross-sectional view, through a holding capacitor, of part of
`
`a pixel array and circuit substrate in the same and/or an9ther embodiment of
`
`the active-matrix display device in accordance with the inv~ntion;
`
`30
`
`Figure 5 is a plan view similar to Figure 2, but stilbwing an:example of a
`network layout feature for the conductive barriers of th 1e ~rive line of a further
`device embodiment in accordance with the invention;
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 007
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`6
`
`Figures 6 and 7 are plan views similar to Figure 2, showing two
`examples of different layout features for the conduct'ive barriers of other
`devices in accordance with the invention, with back-up for row conductors as
`well as the drive line;
`
`5
`
`Figur~s 8 and 9 are circuit diagrams for two modified pixel-drive
`configurations of a pixel area of two further devices in accordance with the
`invention;
`
`Figures 10 to 12 are sectional views of a device: part such as that of
`Figure 1 at stages in its manufacture with one particular embodiment in
`accordance with the invention;
`Figure 13 is a sectional view a device part at the Figure 12 stage,
`illustrating a modification in the insulation of the conduqti'(~ ba~ri~rs of the drive
`line that is also in accordance with the present invention;
`Figure 14 is a sectional view of another embodirpent of a conductive
`barrier construction using a metal coating to form at leas~ part of the drive, line
`in accordance with the invention;
`
`Figure 15 is a cross-sectional view through side-by-side barriers, each
`with conductive barrier material that may be used in different embodiments of
`the invention;
`Figure 16 is a plan view of transverse multiple barrier layout features
`that may be used in different embodiments of the invention; and
`Figure 17 is a cross-sectional view of a barrier. embodiment with
`multiple conductive parts that may be used in different :embodiments of the
`invention.
`
`fi~ramrpa~ic. Relative
`It should be noted that all the Figures are d
`dimensions and proportions of parts of these Figutes have . been shown
`exaggerated or reduced in size, for the sake of clarity an~ convenience in the
`drawings.
`The same reference signs are generally used to refer to
`corresponding or similar features in modified and different .embodiments.
`
`1i
`
`I
`
`10
`
`15
`
`20
`
`25
`
`30
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 008
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`7
`
`5
`
`Embodiments of Figures 1 to 4
`The active-matrix electroluminescent display device of Figure 1
`comprises an array of pixels 200 on a circuit substrate 100. Each pixel 200
`comprises a current-driven electroluminescent element 25 (21,22,23) that is
`connected to a supply line 140,240 by a current-controlling series drive
`element T1 (1-5) in the circuit substrate 100. This series element T1, typically
`a TFT, controls the current through the electrolurnin~scerit element 25
`(21,22,23). As described below, the display can be ve'iY l!arge in area due to
`the construction of these current drive lines 140,240 usin@ conductive barrier
`10 material 240 in accordance with the present invention. Apart from this
`construction of the drive supply lines 140,240 in accordance with the present
`invention, the display may be constructed using known device technologies
`and circuit technologies, for example as in the background references cited
`· hereinbefore.
`
`.....
`
`15
`
`20
`
`2s
`
`30
`
`typically comprises a
`the electroluminescent element 25
`Thus,
`light-emitting diode (LED) of organic semiconductor material 22 between a
`lower electrode 21 and an upper electrode 23.
`In a preferred particular
`embodiment, semiconducting conjugated polymers may be used for the
`electroluminescent material 22. For a LED that emits its light 250 through the
`substrate 100, the lower electrode 21 may be an anode of indium tin oxide
`(ITO), and the upper electrode 23 may be a cathode comprising, for example,
`calcium and aluminium. Figure 1 illustrates a LED construction in which the
`lower electrode 21 is formed as a thin film in the circuit substrate 100. The
`subsequently-deposited organic semiconductor material 22 contacts this
`thin-film electrode layer 21 at a window 12a in a planar insulating layer 12 (for
`example of silicon nitride) that extends over the thin-film structure of the
`substrate 100.
`As illustrated in Figures 1 and 3, the LED 25 and its drive element T1
`are connected ·in series between a pair of voltage supply lines 140,240 and
`230. The line 140,240 (to/from which the drive elements. T1 control the LED
`connection, and hence the current flow) is termed the drive line. The other line
`230 is connected directly to the LED 25. Thus, in the particpular embodiment of
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 009
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`8
`
`Figure 1, the line 230 is formed as a common extension of the upper
`
`electrodes 23 of the pixels 200. In the circuit configuration of Figure 3, the line
`
`230 is grounded and so forms a return line, whereas Vi~l~~ge Vdd is applied to
`the line 140,240 as a power supply line.
`The series drive element T1 typically compris~s a TFT that is formed as
`part of a thin-film circuit within the substrate 100. The su9strate 100 may have
`
`5
`
`an insulating glass base 1 O on which an insulating surface-buffer layer 11, for
`
`example, of silicon dioxide is deposited. The thin-film circuitry is built up on the
`
`layer 11 in known manner. Thus, in addition to TFT T1, the circuit substrate
`
`10
`
`100 typically includes other drive and matrix addressing circuitry, for example
`
`with thin-film elements T2, Ch, 140, 150 and 160 as illustrated in Figure 3.
`
`It
`
`should be understood that Figure 3 depicts, by way of e,xample, one specific
`
`pixel circuit configuration. Other pixel circuit configurations are known for
`
`active matrix electroluminescent display devices.
`
`It should readily be
`
`15
`
`unde.rstood that the present invention may be applied tq the pixel barriers of
`
`such a device regardless of the specific pixel circuit co~fi~urati~n:of the device.
`
`As illustrated in Figure 3, the pixel circuit comprises addressing TFTs
`
`T2 between transverse sets of row (addressing) conductors 150 and column
`
`(data) conductors 160, all of which are formed in the sub$trate 100. Each row
`of pixels is addressed in turn in a frame period by means of a selection signal
`
`20
`
`that is applied·to the relevant row conductor 150 (and hence to the gate of the
`
`addressing TFTs T2 of the pixels of that row). This signal turns on the
`
`addressing TFT T2, so loading the pixels of that row with respective data
`
`signals from the column conductors 160. These data signals are applied to
`
`25
`
`the gate of the individual drive TFT T1 of the respective Aixel. In order to hold
`
`the resulting conductive state of the drive TFT T1, ' this data signal is
`
`maintained on its gate 5 by a holding capacitor Ch that is poupled between this
`
`gate 5 and the drive line 140,240. Thus, the drive currem through the LED 25
`
`of each pixel 200 is controlled by the driving TFT T1 pa!?ed qn a drive signal
`
`30
`
`applied during the preceding address period and storedl as a voltage on the
`
`associated capacitor Ch. In the specific example of Figur~ 3, T1 is shown as a
`
`P-channel TFT, whereas T2 is shown as an N-channel.TF:f.
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 010
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`9
`
`This circuitry can be constructed· with known thin-film technology.
`I
`Figure 1 illustrates the P-channel TFT T1 comprising: an active semiconductor
`
`layer 1 (typically of polysilicon); a gate dielectric layer 2 (typically of silicon
`
`dioxide); a gate electrode 5 (typically of aluminium or polysilicon); and metal
`
`5
`
`electrodes 3 and 4 (typically of aluminium) which contact P-type doped source
`
`and drain regions of the semiconductor layer 1 through windows (vias) in the
`
`over-lying insulating layer(s) 2 and 8. Extensions of these metal electrodes 3
`
`and 4 at the upper level form an interconnection between TFT electrode 3 and
`
`•'-
`
`the lower electrode 21 of the LED and form at least a connection area 140 of
`
`10
`
`In a particular layout embodiment (such as that of
`the drive line 140,240.
`Figure 2), this extension of the metal electrodes 4 Rf !a ror-r may form a
`continuous line 140 for that row. Figure 1 illustrates also~ section through the
`
`address lines 150, which may be, for example, of aluminiym or polysilicon and
`
`which may be formed from the same layer as the TFT gat~s 5.
`
`15
`
`The holding capacitor Ch may be formed similarly, in known manner, as
`
`a thin-film structure inside the circuit substrate 100. Thus, Figure 4 illustrates
`
`such a capacitor Ch that comprises a thin-film conductor plate 155 on a
`
`thin-film dielectric 2 on a thin-film conductive plate 105.
`
`As in known devices, the device(s) of Figures 1 to 4 in accordance with
`
`20
`
`the present invention include physical barriers 210, betw~en at least some of
`
`the neighbouring pixels in at least one direction of the array. These barriers
`
`210 may also be termed "walls", "partitions", "banks", "ribs", "separators", or
`
`"dams", for example. Depending on the particular devicej embodiment and its
`
`manufacture, they may be used in known manner, for e1'a~ple::
`
`25
`
`•
`
`to separate and prevent overflow of a polym~r §olution between the
`
`respective areas of the individual pixels 200 andVor columns of pixels
`
`200, during the provision of semiconducting pol}{mer layers 22;
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`•
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`to provide a self-patterning ability on the subs1rate surface in the
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`definition of the semiconducting polymer or other electroluminescent
`
`30
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`layers 22 for the individual pixels 200 and/or for columns of pixels
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`200 (and possibly even a self-separation of individual electrodes for
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 011
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`10
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`the pixels, for example an individual bottom layer of the upper
`
`electrodes 23);
`
`•
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`to act as a spacer for a mask over the substrate surface during the
`
`deposition of at least an organic semiconductor material 22 and/or
`
`5
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`electrode material;
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`•
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`to form opaque barriers 21 O for a well-definea1 optical separation of
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`the pixels 200 in the array, when light 250 isl emitted through the top
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`(instead of, or as well as, the bottom substrate 100).
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`Whatever their specific use in these known ways, the physical barriers
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`· 10
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`21 O in an embodiment of the present invention are constructed and used in a
`
`special manner. Thus, the pixel barriers 21 O which are provided in accordance
`
`with the present invention are predominantly of electrically-conductive material
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`240 that is insulated from the LEDs 25 and that provides at least a part of the
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`drive line 140,240. The barriers 21 O comprise a bulk or core of conductive
`
`15 material 240 that is preferably metal (for very low resistivity, for example
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`aluminium or copper or nickel or silver). Contact windo~s 12b are present in
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`the inten:nediate insulating layer 12 between the barriers 21 O and the substrate
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`circuitry. The conductive barrier material 240 is connected to the electrode
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`connections 4, 140 for respective drive elements T1 of F3,t least some of the
`
`20
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`pixels 200 at the vias provided by these windows 12b .. 4Js illustrated in Figure
`
`1, its source and drain electrodes connect the main current path of the
`current-controlling drive TFT T1 between the conductive qarrier material 240 -of
`the drive line and the lower electrode 21 of the LED 25.
`These drive line connections (and/or composite nature of the drive line
`140,240) with the conductive barrier material 240 serve to decrease voltage
`
`25
`
`drops along the line 140,240 as it extends across the array. As a result, the
`
`displays can be made very large in area, for example at least a metre (i.e. over
`
`30 inches) wide. Before the advent of the present invention, it was difficult
`
`(perhaps even impossible) to make very large active-matrix electroluminescent
`
`30
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`displays due to voltage errors along the drive lines when conducting current in
`the conducting light-emitting state. However, the presei:1t invention can also
`
`be used with advantage in smaller displays, to improve th~ir image quality.
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 012
`
`

`

`WO 03/079442
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`PCT /IB03/00999
`
`11
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`Thus, along the line 140,240, the conductive barriet material 240 has a
`cross-sectional area that is at least twice (possibly everi ;:ln order of
`magnitude) larger than that of the conductor layer that 1pr(j)vides the electrode
`connection 4, 140 to the drive element T1. Typically, the conductive barrier
`5 material 240 may have a thickness Z that is a factor 0f two or more (for
`example at least five times) larger than the thickness z of this conductor layer
`140 in the circuit substrate 100. In a specific example, Z may be between 2µm
`and 5µm as compared with 0.5µm or less for z. Typically, the conductive
`barrier material 240 may have a line width Y that is the same width ( or even at
`least twice as large) as the line width y of the conductor layer 140.
`In a
`
`I
`
`10
`
`specific example, Y may be 20µm as compared with 10µm;tor y.
`It is important to note a further feature that is pr~sent in this device
`
`structure, for reducing the effect of voltage variations on the supply lines 230
`and 140,240. Thus, a smoothing capacitor Cs is formed between the drive line
`
`140,240 (that comprises the conductive barrier matericjl,I ~40) find the further
`supply line 230 (that is associated with the upper electrddes ?3 of the LEDs
`25). As illustrated in Figure 1, the sides and top of thf) conductive barrier
`material 240 are coated with an insulating layer 40. The thickness and
`
`dielectric properties of this insulating coating 40 can be chosen to form a
`capacitor dielectric of the smoothing capacitor Cs. The other plate of the
`capacitor Cs is formed by the supply line 230 ( comprising and/or connecting
`the LED upper electrodes 23), that extends on this insulating coating 40 over
`the top of the conductive barrier material 240. Typically, this insulating coating
`
`15
`
`20
`
`40 may be of silicon dioxide or nitride or of aluminiuni oxide and have a
`thickness in the range of 10nm (nanometres) to 0.5µm (mirrometres).
`
`25
`
`Layout Embodiment of Figure 2
`
`30
`
`In the specific layout example of Figure 2, the l~tensipm, of the TFT
`electrodes 4 of a pixel row form a continuous line 140!for that row. This line
`140 extends parallel to barriers 210(240,40). These bapiers 210 (shown in
`broken outline in Figure 2) extend parallel to the address ((row) conductors 150
`of the substrate 100.
`
`,
`
`I
`
`LG Display Co., Ltd.
`Exhibit 1006
`Page 013
`
`

`

`WO 03/079442
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`PCT /IB03/00999
`
`12
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`As illustrated in Figure 2, when the barriers 210(2'40,40) extend parallel
`
`to one or more lines (such as lines 140 and 150 in Figure 2), these lines may
`
`be fully overlapped by the barriers 120. Indeed the width Y of the barriers 21 O
`(240,40) of Figure 2 is so large as to overlap both the lines 140 and 150.
`5 Nonetheless, the thin-film pixel circuitry of Figure 3 may encroach somewhat
`
`into the pixel area as illustrated by the hatched circuit area 120.
`The conductive barrier material 240 is connected at the vias 12b to a
`
`node of the drive element T1 and one plate of the holding capacitor Ch.
`
`Figure 2 illustrates an embodiment in which each pixel ~00 has a respective
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`I
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`10
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`via 12b between the conductiv~ barrier material 24P and the electrode
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`connection 140,4 for the respective drive element T1 ofi tije pi~el}
`In the Figures 1 and 2 illustration, 'at least mosf ofl the drive element T1
`
`is located below the conductive barrier material 240. Ttiie width Y and length
`of the conductive barrier material 240 permits at least! most of the holding
`
`I
`
`15
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`capacitor Ch to be located below the conductive barrier material 240, for
`example in the Figures 2 and 4 illustration. The drive element T1 of each pixel
`
`may have its respective electrode 4 located at a/the via 12b and/or the
`respective capacitor plate 155 may be located at a/the via 12b.
`
`Each barrier 210(240,40)·of the Figure 2 layout may extend across the
`20 whole array. Thus, it may form a continuous supply line of the conductive
`
`barrier material 240 that is connected to electrode connections 4, 140 for the
`
`respective drive elements T1 of the respective pixels 200. In this case, it may
`
`parallel the line 140. However, if the line resistance of t~e conductive barrier
`
`material 240 is itself sufficiently low, it can simply!'! riplace the substrate
`conductor line 140. Thus, it is not necessary for the exte~sions 140 of the TFT
`
`25
`
`electrodes 4 to form a continuous line, and an increase lin pixel aperture can
`be achieved by omitting lengths of the line 140 in most of the pixel area.
`
`Layout Embodiment of Figure 5
`
`30
`
`The specific layout example of Figure 5 is a modification of that of
`Figure 2. In this modification, the barriers 210(240,40) extend in both row and
`
`column directions of the array. Thus, in this particular embodiment, the
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`LG Display Co., Ltd.
`Exhibit 1006
`Page 014
`
`

`

`WO 03/079442
`
`PCT /IB03/00999
`
`13
`
`barriers 210(240,40) are interconnected between pixels to form a network of
`
`conductive barrier material 240 in bot