Case 6:20-cv-00636-ADA Document 48-17 Filed 02/16/21 Page 1 of 27
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`Exhibit 14
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`Case 6:20-cv-00636-ADA Document 48-17 Filed 02/16/21 Page 2 of 27
`US 20030035906A1
`(19) United States
`(12) Patent Application Publication (io> Pub. No.: US 2003/0035906 Al
`Feb. 20,2003
`(43) Pub. Date:
`Memarian et al.
`
`(54) TRANSPARENT CONDUCTIVE
`STRATIFORM COATING OF INDIUM TIN
`OXIDE
`
`(52) U.S. Cl.
`
`428/1.3; 428/1.33; 427/126.3;
`427/419.1; 136/256
`
`(76)
`
`Inventors: Hassan Memarian, Northridge, CA
`(US); Hitesh Patel, Moreno Valley, CA
`(US)
`
`(57)
`
`ABSTRACT
`
`Correspondence Address:
`BACON & THOMAS, PLLC
`625 Slaters Lane, 4th Floor
`Alexandria, VA 22314-1176 (US)
`
`(21) Appl. No.:
`
`09/851,321
`
`(22)
`
`Filed:
`
`May 9, 2001
`
`Publication Classification
`
`(51)
`
`Int. Cl.7
`
`C09K 19/00; B05D 5/12;
`H01L 31/00
`
`A transparent electrically conductive device which includes
`an indium tin oxide film is improved by providing an indium
`tin oxide film which contains a graded stack of individual
`indium tin oxide layers wherein the atomic percent of tin in
`the layers can be individually selected. Each indium tin
`oxide layer of the film contains 1-99 atomic percent tin.
`Each layer is made by a physical vapor deposition process
`or by sputter coating. Preferably the film which contains a
`plurality of indium tin oxide layers is applied to a transparent
`flexible substrate such as a polymeric sheet. Optional primer
`layers, hardcoat layers and topcoat layers may be included
`in the device.
`
`

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`Patent Application Publication Feb. 20,2003 Sheet 1 of 13 US 2003/0035906 Al
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`Patent Application Publication Feb. 20,2003 Sheet 2 of 13 US 2003/0035906 Al
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`Figure J
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`

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`Patent Application Publication Feb. 20,2003 Sheet 3 of 13 US 2003/0035906 Al
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`AUGER PROFILE (Atomic Concentration)
`
`0
`
`1« 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400
`DEPTH (angstroms)
`I"
`
`ό"
`
`ercen
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`

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`Patent Application Publication Feb. 20,2003 Sheet 4 of 13 US 2003/0035906 Al
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`AUGER PROFILE (Atomic Concentration)
`
`0
`
`100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400
`DEPTH Ungstroiis)
`
`F u r <z.
`
`

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`Patent Application Publication Feb. 20,2003 Sheet 5 of 13 US 2003/0035906 Al
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`ftUGER PROFILE (Atonic Concentration)
`
`100
`
`0
`
`100 200 300 400 500 600 /00 800 W 1000 1100 1200 1300 1400
`DEPTH (angstroiiis)
`Figure. Qa-
`
`

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`Patent Application Publication Feb. 20,2003 Sheet 6 of 13 US 2003/0035906 Al
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`AUGER PROFILE (Atonic Concentration)
`
`0
`
`100 200 300 400 500 600 700 800 ' 900 1000 1100 1200 1300 1400
`DEPTH (angstroms)
`l-iGure. ζ>
`
`Perc.gn
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`

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`Patent Application Publication Feb. 20,2003 Sheet 7 of 13 US 2003/0035906 Al
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`flUGEB PROFILE (Atonic Concentration)
`
`wo
`
`0
`
`100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400
`
`DEPTH (wgstrc«)
`
`F\ o r e. ~i
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`

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`Case 6:20-cv-00636-ADA Document 48-17 Filed 02/16/21 Page 10 of 27
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`Patent Application Publication Feb. 20,2003 Sheet 8 of 13 US 2003/0035906 Al
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`AUGER PROFILE (Atonic Concentration)
`
`0
`
`100 200 300 400 500 '600 700 800 900 1000' 1100 1200 '1300 1400
`DEPTH (angstroms)
`Fi ~7 b
`
`Perce
`
`

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`Patent Application Publication Feb. 20,2003 Sheet 9 of 13 US 2003/0035906 Al
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`AUGER PROFILE (Atonic Concentration)
`
`100
`
`Percent
`
`0
`
`100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400
`DEPTH (angstroms)
`
`

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`Patent Application Publication Feb. 20,2003 Sheet 10 of 13 US 2003/0035906 Al
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`iW PROFILE (Atonic Concentration)
`
`0
`
`100 200 300 400 500 600 700 800 ?00 1000 1100 1200 1300 1400
`DEPTH (angstroms)
`S’ b
`
`

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`Case 6:20-cv-00636-ADA Document 48-17 Filed 02/16/21 Page 13 of 27
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`Patent Application Publication Feb. 20,2003 Sheet 11 of 13 US 2003/0035906 Al
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`u r e
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`Patent Application Publication Feb. 20,2003 Sheet 12 of 13 US 2003/0035906 Al
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`Target Voltage
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`1 4 7 101316192225283134374043
`Oxygen Flow
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`Fl g u r e, i
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`

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`Patent Application Publication Feb. 20,2003 Sheet 13 of 13 US 2003/0035906 Al
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`VACUUM iHb
`PUMP
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`11
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`

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`1
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`Feb. 20, 2003
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`TRANSPARENT CONDUCTIVE STRATIFORM
`COATING OF INDIUM TIN OXIDE
`
`BACKGROUND OF THE INVENTION
`[0001] 1. Field of the Invention
`[0002] The present invention pertains to the field of trans­
`parent electrical conductive coatings made of indium tin
`oxide which are applied to transparent substrates, especially
`flexible transparent polymeric film substrates. The invention
`also pertains to the method of making the coated substrates
`and the use of the coated substrates in electronic devices
`which require transparent conductive oxide (TCO) films
`having excellent electrical conductivity, mechanical dura­
`bility and high transparency. Such electronic devices include
`liquid crystal displays (LCD), touch panels (TP) and pen
`entry devices, electroluminescent lamps (EL), personal digi­
`tal assistants (PDA), organic light emitting devices (OLED),
`etc.
`[0003] 2. Background Information
`[0004] Substrates such as flexible transparent polymeric
`films having a TCO coating thereon are widely used in the
`above noted devices because these coatings possess high
`optical transparency, high electrical conductivity and good
`mechanical stability. Indium oxide-tin oxide (indium-tin
`oxide commonly referred to as ITO) is often used as the
`TCO coating.
`[0005] The indium-tin oxide coating used in this field of
`technology and in the present invention is a non-stoichio-
`metric n-type semiconductor which exhibits high visible
`transmittance, low resistance and high infrared reflectance.
`For this reason, thin films of ITO are commonly used as the
`TCO coating in the above noted devices. Conventional
`reactive sputtering from a InSn alloy in an oxygen contain­
`ing atmosphere (e.g., argon-oxygen atmosphere) is used to
`apply the ITO film or coating onto the substrate. A conduc­
`tive ITO film is a partially oxidized mixture of indium and
`tin and thus the optoelectronic properties of such films are
`greatly affected by the level of oxygen admitted into the
`plasma during the deposition. The amount of oxygen in the
`ITO films used in this field of technology is well known to
`those skilled in the art.
`[0006] On one hand, films with too little oxygen exhibit
`high sheet resistance and low visible transmittance. On the
`other hand, at a fully reacted state (complete oxidation), one
`achieves a transparent oxide with very high sheet resistance
`and high visible light transmittance. The manner of proceed­
`ing from a metallic layer to a fully oxidized layer depends
`on the feedback and control mechanisms employed during
`reactive deposition processes which are well known to those
`skilled in the art.
`[0007] In the production of ITO coatings from an InSn
`target on a polymeric web (i.e., sheet), the in-situ measure­
`ment and control of the oxidation level is of pivotal impor­
`tance. The traditional constant pressure controlled reactive
`sputtering of ITO works well and produces films with
`adequate properties. However, the use of such traditional
`constant pressure controlled reactive sputtering of ITO does
`not meet the demands of more stringent and sophisticated
`applications. This is because reactive sputter deposition of
`indium-tin oxide (ITO) from an alloy target is an extremely
`sensitive process. The quality of the deposited ITO is
`
`dependent on the ability to maintain a certain constant
`partial pressure of oxygen in the sputtering zone during the
`deposition process. Minor changes in the substrate outgas­
`sing, pumping speed, target condition or arcing can result in
`significant changes in the oxidation level of the deposited
`layer, thus producing an inferior conducting film. When
`producing sputtered ITO on continuous flexible substrates,
`on-line monitoring and feedback control in real time is
`essential for high quality products.
`[0008] There are various methods in use today which
`provide for the monitoring and control of the reactant
`species in the glow discharge. These methods include direct
`or indirect partial pressure measurements and optical emis­
`sions spectroscopy. In particular, such methods include the
`use of a residual gas analyzer (RGA), an optical gas con­
`troller (OGC) or a plasma emission monitor (PEM). Each of
`the above devices provide a means for monitoring and
`controlling the amount of oxygen during deposition of the
`metal. It is well know to those skilled in the art that the
`amount of oxygen must be kept at a level to produce the
`aforementioned non-stoichiometric ITO coating which is
`not completely oxidized. Thus the oxygen atmosphere dur­
`ing deposition must be maintained at an oxygen deficiency
`to produce the required non-stoichiometric oxide coating.
`[0009] ITO coated films are conventionally used in a wide
`range of applications which include touch panel devices.
`Touch panel devices have two opposing surfaces of the ITO
`films separated by spacers. Contact is made between the two
`opposing surfaces when the front surface is depressed by a
`finger or touch pen. Depending on the type of device, the
`location of the input is decoded by the electronic interface
`according to known technology. LCD devices typically
`include an array of transparent ITO electrodes which define
`the display segment or pixels to be activated. In EL displays
`electrical energy is converted to light energy (lumines­
`cence). EL displays use a thin film of phosphor sandwiched
`between dielectric layers that is sandwiched between two
`electrodes, one of which is ITO. When an AC voltage is
`applied to any of the electrodes, the phosphor will be excited
`so that it emits light.
`[0010] Reliability during continuous operation is a prob­
`lem associated with these devices. In the touch panel device
`it has been observed that the electrical resistance increases
`after continuous cycling. The ITO surfaces crack or fracture
`at the touch location and these fractures propagate over time
`to totally disrupt the operation of the device. Countermea­
`sures have been employed in these devices to help prevent
`the aforementioned cracking problem. In particular, it is
`known to deposit a thin layer of palladium, platinum, gold
`or oxides of these metals onto the ITO film to protect the
`ITO and/or increase the surface adhesion properties of the
`ITO layer for subsequent processing. Methods to promote
`crystallization of the ITO surface after deposition have also
`been used to grow a hard surface. Problems have also been
`observed during the fabrication of EL lamps. It has been
`observed that the ITO film in EL lamps becomes delami­
`nated from the polymeric substrate during processing of the
`phosphor layer. Pretreatment methods have been utilized to
`increase the surface energy of the substrates during deposi­
`tion, but with limited success. Other techniques such as
`applying a thin metallic or oxide layer on top of the ITO has
`also been tried with good results.
`
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`[0011] As active metric liquid crystal displays (AMLCD)
`become the dominant display for portable systems such as
`pagers, phones and personal digital assistants, ruggedness
`and impact resistants become highly desirable for handling
`considerations as well as for flexibility during their fabrica­
`tion.
`
`SUMMARY OF THE INVENTION
`[0012] It is an objective of the present invention to provide
`an improved sputtered TCO coating of ITO on a transparent
`substrate, especially a transparent polymeric film substrate,
`for use in applications where TCO films are conventionally
`employed.
`[0013] It is also an objective of the present invention to
`improve conventional electronic devices which include a
`TCO as a component thereof by using the ITO of the present
`invention as the TCO.
`[0014] It is also an objective of the present invention to
`provide a method for making an improved transparent
`conductive coating of ITO on a transparent substrate.
`[0015] These and other objectives are obtained by forming
`a multilayered transparent conductive film or coating of ITO
`on a transparent substrate wherein the ITO film or coating
`includes distinct layers of transparent conductive ITO. The
`term “transparent conductive coating of ITO” as used herein
`refers to transparent conductive ITO coatings which are
`conventionally employed in well known electronic devices
`which require a TCO. Such devices include conventional
`liquid displays (LCD), touch panels (TP), electrolumines­
`cent lamps (EL), personal digital assistants (PDA), organic
`light emitting devices (OLED), etc. Henceforth such trans­
`parent conductive ITO coatings will be referred to herein as
`ITO coatings. In addition, the term “conductive” as used
`herein refers to electrical conductivity.
`[0016] The layers of ITO are spatially distinct from each
`other and differ in terms of the proportion of indium to tin
`in each layer. Aside from the proportion of indium to tin (i.e.,
`the relative amount of indium and tin on an atomic basis) in
`each layer, the compositional characteristics of the ITO
`coatings are otherwise the same as the nonlayered ITO
`which is conventionally used in TCO materials.
`[0017] The composition (i.e., relative amount of In and Sn
`in each layer) is selected in each layer to provide desired
`properties at varying depths in the ITO coating. It has been
`discovered that the problems relating to lack of durability
`and other mechanical and physical disadvantages of the
`prior art ITO coatings can be overcome by providing the
`multilayered ITO of the present invention without adversely
`affecting the optical properties of the ITO film. For example,
`in the present invention the composition of one or more
`layers of the ITO film can be selected to provide a chemical
`resistance barrier which protects the entire structure while
`the composition of the other ITO layers can be selected to
`optimize other characteristics without adversely affecting
`optical properties of the device. The composition of any of
`the ITO layers can be custom made to provide desired
`physical characteristics at specified locations on the ITO
`surface and within the depth of the ITO coating.
`[0018] The TCO film of the present invention comprises a
`plurality of ITO layers with at least one ITO layer being
`different (i.e., having a different In to Sn ratio) from one or
`
`more other ITO layers. Thus in its simplest embodiment, a
`substrate has an inner ITO layer thereon and an outer
`different ITO layer on the inner ITO layer. Additional ITO
`layers may be included.
`[0019] The plurality of layers forms a stack of two or more
`layers, each layer having a finite thickness wherein the
`composition or proportion of In to Sn is substantially
`uniform throughout the thickness thereof. By substantially
`uniform it is meant that a given layer is as uniform as
`humanly possible when sputter coated using a homogenous
`target containing the desired ratio of In to Sn. The uniform
`composition of each layer exists as a finite thickness, e.g.,
`about at least 50 angstroms, preferably 50-600 angstroms, in
`each layer. Thus there is no continuous gradient of compo­
`sitional change throughout the entire thickness of the entire
`ITO coating. Naturally there may be a zone of nonunifor­
`mity between layers due to inherent imperfections in the
`sputtering process when one thin ITO layer is sputter coated
`(using one target) onto a different thin ITO layer (using a
`different target). Such zones may be referred to as transition
`zones between the ITO layers. The changes in composition
`through the transition zones may be gradual.
`[0020] It is possible that two or more ITO layers in a stack
`containing at least three ITO layers, may be compositionally
`identical to each other. However, compositionally identical
`layers are separated from each other by another composi­
`tionally different layer.
`[0021] The substrate coated with the ITO layers may
`include additional layers which are typically used in TCO
`devices in this field of technology. Such layers include
`protective top coat layer, primer layer, hard coat, etc. The
`substrate may thus include other layers as a component
`thereof.
`[0022] Since the above-described multilayered ITO film
`has compositionally different ITO layers wherein the com­
`positional difference lies in the In to Sn atomic ratio, the ITO
`coating may be referred to as a graded ITO stack.
`[0023] The substrate used in the present invention may be
`any of the commonly employed substrates which are typi­
`cally used in electronic devices which employ a TCO
`coating. Such well known substrates include transparent
`flexible polymeric film or sheets. Suitable polymers for
`making the polymeric film include polyester such as poly­
`ethylene terephthalate (PET), polyurethane, polysulfone,
`and polycarbonate.
`[0024] Sputtering is advantageously used to deposit the
`ITO layers of the TCO film so that high temperatures and
`other physical and chemical conditions which could harm
`the substrate, especially a polymeric substrate, can be
`avoided. Other physical vapor deposition procedures, such
`as evaporative coating, may be employed. Sputtering is
`particularly advantageous because it can deposit the ITO
`layer at ambient or room temperature (e.g., about 70° F.).
`Any conventional sputtering method and apparatus may be
`used; it being understood that each compositional layer
`requires the use of a target which has the corresponding
`proportion of In to Sn. Sputtering coaters which advance a
`polymeric sheet or web from one roll to another roll with a
`plurality of sputtering stations positioned in the path of the
`sheet or web are particularly advantageous because the
`various layers of ITO can be sputter coated onto the sheet in
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`one pass of the sheet as it advances from one roll to the other
`roll. Such sputtering coaters are well known and are com­
`mercially available. An example of such a sputtering device
`is shown in U.S. Pat. No. 4,977,013, the specification of
`which is incorporated herein by reference.
`[0025] The sputtering target may be an indium-tin alloy.
`When sputtering with an indium-tin alloy, the sputtering is
`performed in an atmosphere which contains oxygen accord­
`ing to well known techniques so that the deposited material
`is the desired oxides of indium and tin. As noted above, the
`indium tin oxide coating has a nonstoichiometric amount of
`oxygen so that the coating has the required electrical con­
`ductivity and transparency; and the amount of oxygen
`contained in the ITO coating in the present field of technol­
`ogy is well known to those skilled in the art. Alternatively,
`instead of using an alloy target in an oxidizing atmosphere,
`the sputtering may use a tin oxide-indium oxide ceramic
`(e.g., a mixed ceramic powder of indium oxide and tin
`oxide) as the target. Such a target should have an oxygen
`content equal to the oxygen content in the corresponding
`film or ITO layer which is deposited.
`
`[0026] The amount of indium and tin in a particular ITO
`layer can be expressed in terms of atomic percentage
`wherein the atomic percent of one of the two metals is in
`relationship to the total content of those two metals in the
`particular layer.
`[0027] Thus an ITO layer having 1% tin will have 99%
`indium and an ITO layer having 5% tin will have 95%
`indium. Similarly an ITO layer having 99% tin will have 1%
`indium and an ITO layer having 95% tin will have 5%
`indium. The above percentages are on an atomic basis.
`Unless stated to the contrary, all of the percentages of tin and
`indium described herein are on an atomic basis as described
`above.
`[0028] The present invention is based on the discovery
`that TCO’s having an atomic percentage of 1-99% tin
`deposited by sputtering techniques can be improved by
`stacking ITO layers in the manner described above to form
`a graded array or stack of the coatings. Each ITO layer of the
`stack embodies a specific physical property that has been
`tailored for the desired device which uses the TCO layer. For
`example the touch input device has a front surface ITO layer
`which possesses greater tin content than the back surface
`that is in contact with the polymeric film. This type of
`structure has enhanced mechanical characteristics for con­
`tinuous touch input while maintaining excellent bulk con­
`ductivity and high transparency comparable to the conduc­
`tivity and transparency of conventional single composition
`ITO materials. More specifically, multi-compositional
`graded ITO structures of the present invention provide for
`more rugged features which are suitable for a variety of new
`electronic devices. The multi-compositional ITO also pos­
`sesses greater environmental stability when exposed to high
`temperature and humidity conditions.
`[0029] It has been discovered that the TCO’s of the present
`invention deposited by sputtering techniques are more
`durable and possess greater flexibility which is required for
`touch type devices in comparison to the TCO’s of the prior
`art.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`[0030] FIG. 1 is a cross-sectional representation of an
`embodiment of the invention which includes two different
`ITO layers on a substrate.
`[0031] FIG. 2 is a cross-sectional illustration of another
`embodiment of the invention which includes a plurality of
`ITO layers and other layers on a substrate.
`[0032] FIG. 3 is a cross-sectional illustration of another
`embodiment of the invention which includes a plurality of
`ITO layers and other layers on a substrate.
`[0033] FIG. 4 is a cross-sectional illustration of another
`embodiment of the invention which includes a plurality of
`ITO layers on a substrate.
`[0034] FIGS. 5A-8B are Auger graphs which show the
`compositional changes throughout the depth of the ITO
`layers which are used in the examples of the invention.
`[0035] FIG. 9 is a schematic drawing which illustrates the
`configuration setup of a plasma emission monitor.
`[0036] FIG. 10 is a graph which illustrates the typical
`indium intensity and cathode voltage as a function of oxygen
`flow.
`[0037] FIG. 11 depicts schematically a three chamber
`sputter roll coater which can be used to deposit the coatings
`of this invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION AND PREFERRED
`EMBODIMENTS
`[0038] In a preferred embodiment the substrate is a trans­
`parent material, preferably a transparent polymer. Most
`preferably the substrate is a flexible polymeric sheet, capable
`of being provided in a roll format. Examples of suitable
`polymeric substrate material include PET and polycarbon­
`ate. A preferred substrate is heat stabilized PET. Heat
`stabilized PET film is well known to those skilled in the art.
`During heat stabilization the film is stabilized against shrink­
`age by heating and stretching the film. In addition transpar­
`ent materials which are conventionally used in this field of
`technology may be used in the present invention.
`[0039] The ITO layers and other materials used to make
`the TCO coated substrate should have a high degree of
`transparency. The standard for transparency may be the
`same as the transparency standards employed for conven­
`tional TCO coated substrates used in this field of technology.
`Preferably the materials such as the ITO layers should have
`a high degree of transparency so that the overall visible light
`transmission of the TCO coated substrate is at least 75%,
`more preferably at least 85%.
`[0040] The ITO layers used in the present invention have
`a refractive index (n) in the range of 2.0 to 2.2 within a
`visible range of 450 nm and 650 nm. The refractive index of
`a material is the ratio of the speed of electromagnetic energy
`in a vacuum (or, for practical purposes, in air) to that in a
`transparent medium.
`[0041] The ITO layers used in the present invention typi­
`cally have an absorption coefficient in the range of 0.01 to
`0.02 within the visible light transmittants of 450 nm and 650
`nm. Absorption coefficient of a material is defined as a
`
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`measure of attenuation caused by absorption of electromag­
`netic energy that results from its passage through a medium.
`It is described by the term “k” and in usually expressed in
`units of reciprocal distance.
`[0042] The ITO layers form a graded ITO film. The graded
`ITO film preferably has a sheet resistance which varies from
`1 to 10,000 Ω per square.
`[0043] The various embodiments of the present invention
`include a transparent electrically conductive film of indium
`tin oxide on a substrate wherein the film of indium tin oxide
`has a proportion of indium to tin atoms which is nonuniform
`throughout the thickness of the film such that the indium and
`tin atoms are distributed throughout the thickness of the film
`to form a plurality of indium tin oxide layers, each of which
`has a finite thickness (i.e., the film of indium tin oxide
`comprises a plurality of indium tin oxide layers so that the
`film is in the form of a graded stack of ITO layers). The
`proportion of indium and tin is substantially uniform
`throughout the finite thickness of any given layer. In addi­
`tion, the various embodiments of the invention may include
`any number and combination of primer layer or layers and
`hardcoat layer or layers to achieve benefits which are well
`known to those skilled in the art through the use of such
`hardcoat and primer layers.
`[0044] One or more layers of transparent electrically con­
`ductive indium zinc oxide (IZO) layers may also be included
`in the various embodiments of this invention. An example of
`an IZO layer is the IZO layer described in U.S. Pat. No.
`6,040,056; the specification of which is incorporated herein
`by reference. Preferably the IZO layer contains zinc in the
`amount of O.f to 9.99% by weight based upon the total
`weight of zinc and indium in the layer (i.e., atomic weight
`percent). The IZO layer or layers may be located anywhere
`in the multilayered articles of the present invention. The IZO
`layer or layers may be applied by known coating techniques
`such as vacuum coating especially sputter coating. Thus, the
`transparent and electrical characteristics of an IZO layer
`may be obtained by incorporating such a layer in the present
`invention. In addition, the IZO layer may also function as a
`protective topcoat layer or as an adhesion primer layer as
`further described below.
`[0045] In its simplest embodiment, the present invention
`includes a substrate which contains a first transparent con­
`ductive ITO layer thereon and a second transparent conduc­
`tive ITO layer applied to the first ITO film. The first and
`second ITO layers in this simplest embodiment will have
`different relative amounts of indium and tin. The substrate
`may have any desirable thickness taking into consideration
`the type of device in which the TCO coated film is to be
`used. The thicknesses of such coated films are well known
`to those skilled in the art. Preferably the substrate thickness
`will vary in the range of 1-25 microns. The thickness of each
`ITO layer preferably varies in the range of 5-f0,000 ang­
`stroms. Preferably the thickness of the multilayered ITO film
`is 10-100,000 angstroms.
`[0046] The simplest embodiment of the invention as
`described above is illustrated in FIG. 1. The embodiment of
`the invention illustrated in FIG. 1 includes substrate 1, first
`transparent conductive ITO layer 2 and second transparent
`conductive ITO layer 3. The amount of tin in each of the
`layers 2 and 3 has an atomic percentage in the range of 1%
`to 99% relative to the amount of indium and tin contained
`therein.
`
`[0047] Additional embodiments of the invention are illus­
`trated in FIG. 2. FIG. 2 includes substrate 1, first ITO layer
`2 and second ITO layer 3. The substrate and ITO layers
`illustrated in FIG. 2 have the same characteristics as the
`corresponding numbered layers in FIG. 1. Throughout this
`specification, it is to be understood, unless indicated to the
`contrary, that the same reference numerals used throughout
`the figures pertain to the same elements.
`[0048] A transparent hardcoat is advantageously applied
`to flexible substrates or at other locations. The hardcoat layer
`provides enhanced mechanical characteristics as well as
`barrier properties. The hardcoat layers which are optional in
`this invention, may be applied by any conventional tech­
`nique such as by wet chemistry, vacuum deposition or
`sputter coating. The positions of three optional hardcoat
`layers in FIG. 2 are illustrated by reference numerals 7A, 7B
`and 7C. Thus, a hardcoat layer may be deposited on either
`side of the substrate. In order to enhance adhesion of the
`hardcoat to the substrate, a primer layer may be deposited on
`either side of the substrate. Thus FIG. 2 shows two primer
`layers 8A and 8B deposited on either side of substrate 1. The
`above-noted primer layers are optional. The primer and
`hardcoat layers may be utilized in any desired location in the
`device at the present invention.
`[0049] FIG. 2 also illustrates an additional primer layer
`8C deposited on top of hardcoat layer 7B. Primer layer 8C
`serves to improve the adhesion of an additional optional
`hardcoat layer 7C.
`[0050] The embodiment illustrated in FIG. 2 contains at
`least 2 ITO layers (i.e., layers 2 and 3). An optional third ITO
`layer 4 may be deposited on top of ITO layer 3. Additional
`optional ITO layers represented by reference numeral 5 may
`be included on top of ITO layer 4 and/or next to hardcoat
`layer 7a.
`[0051] A protective topcoat layer 6 is optionally applied
`on the top and/or on the bottom of the multilayered structure
`shown in FIG. 2. The protective topcoat layers may be the
`same or different from each other. Any combination of
`hardcoat layers, primer layers and graded ITO stacks may be
`used in the invention in between the optional protective
`topcoat layers.
`[0052] The optional hardcoat layer or layers may be the
`same or different from each other. Preferably each hardcoat
`layer has a thickness which ranges from 0.5-25 microns,
`more preferably from 5000 to f00,000 angstroms. Typically,
`the hardcoat layer is chosen to be vacuum compatible for
`reduced degassing properties so that there is a minimum of
`degassing when additional materials are vacuum deposited
`onto the hardcoats. Suitable materials for the hardcoat layers
`include polyurethane, polymerizable long chain acrylics and
`methoxsiloxanes, silicates, densely cross-linked acrylic
`polymers, solvent-case epoxies and combinations of the
`above.
`[0053] A preferred hardcoat useful in this invention is an
`inorganic hardcoat having an index of refraction between
`about 1.4 and about 2.0. Such a hardcoat may be made from
`A12O3 and/or Si02.
`[0054] When two or more primer layers are used in the
`invention, they may be the same or different from one
`another. The primer layer has an average thickness of about
`2 angstroms to W0,000 angstroms, preferably 5 angstroms
`
`

`

`Case 6:20-cv-00636-ADA Document 48-17 Filed 02/16/21 Page 20 of 27
`
`US 2003/0035906 Al
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`5
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`Feb. 20, 2003
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`to 100,000 angstroms. In one embodiment the primer layer
`is 5-10,000 angstroms thick. The primer layer or layers used
`in this invention may be made from any of the organic or
`inorganic materials which are currently used as primer
`layers in the prior art TCO coated films used in the techno­
`logical field of this invention.
`[0055] The primer layer or layers may be selected to
`facilitate adhesion and/or to serve as a barrier. Suitable
`materials for use as an adhesion primer layer include metal,
`metal nitride, metal oxide and metal carbide. Organic com­
`pounds may be used for a barrier primer layer. Organic
`barrier