as) United States
`a2) Patent Application Publication co) Pub. No.: US 2011/0007011 Al
`
` Mozdzyn (43) Pub. Date: Jan. 13, 2011
`
`
`US 20110007011A1
`
`Related U.S. Application Data
`
`(60) Provisional application No. 61/224,999, filed on Jul.
`13, 2009, now abandoned.
`Publication Classification
`
`(54) CAPACITIVE TOUCH SCREEN WITH A
`MESH ELECTRODE
`
`(75)
`
`Inventor:
`
`Larry Stephen Mozdzyn, Garland,
`TX (US)
`
`CorrespondenceAddress:
`
`MARTIN & ASSOCIATES, LLC
`P O BOX 548
`CARTHAGE, MO 64836-0548 (US)
`
`(73) Assignee:
`
`OCULAR LCD INC., Dallas, TX
`(US)
`
`(21) Appl. No.:
`
`12/824,167
`
`(22)
`
`Filed:
`
`Jun. 26, 2010
`
`(51)
`
`Int. Cl.
`
`(52) Vea
`
`(2006.01)
`
`345/173
`
`OS.
`
`C1. ieee cseescneseeeeeseneeseeaeeeeecneseneeeaeees
`(57)
`ABSTRACT
`An improved touch screen provides enhancedelectrical per-
`formance andoptical quality. The electrodes on the touch
`screen are made of a mesh of conductors to reduce the overall
`electrode resistance thereby increasing the electrical perfor-
`mance without sacrificing optical quality. The mesh elec-
`trodes comprise a mesh pattern of conductive material with
`each conductor comprising the mesh having a very small
`width such that the conductors are essentially invisible to the
`user of the touch screen.
`
`Pa 200
`210 (3 Places)
`122
`120
`212
`110 Top Glass
`
`
`
`224
`
`LCD Display Layers 126
`
`418 Column
`Electrodes
`
`114 Adhesive
`
`112
`
`Bottom
`Glass
`
`128 Light
`
`PETITIONERS
`
`Exhibit 1005, Page 1
`
`PETITIONERS
`Exhibit 1005, Page 1
`
`

`

`Patent Application Publication
`
`Jan. 13, 2011 Sheet 1 of 3
`
`US 2011/0007011 Al
`
`132
`
`122
`
`ia
`
`Va 100
`
`124
`
`
`
`
`
`116
`116
`
`110 Top Glass
`
`418 Column
`Electrodes
`114 Adhesive
`
`412 Bottom Glass
`
`130
`LCD Display Layers
`PoPtTEPTTR126 Back Light
`FIG. 1
`Light
`(Prior Art)
`
`128
`
`Li
`
`yo 200
`210 (3 Places)
`122
`120
`212
`110 Top Glass
`
`
`
`HUW 114 Adhesive
`Bottom
`12 Glass
`
`41g Column
`
`Electrodes
`
`126
`128 Light
`
`PETITIONERS
`
`Exhibit 1005, Page 2
`
`224 Tat
`
`HUW HUE
`
`
`
`LCD Display Layers
`13
`
`
`FIG. 2
`
`PETITIONERS
`Exhibit 1005, Page 2
`
`

`

`Patent Application Publication
`
`Jan. 13, 2011 Sheet 2 of 3
`
`US 2011/0007011 Al
`
`
`
`210(3 Places) 312
`
`
`
`
`
`
`
`
`
`
`
`
`
` 310
`
`(3 Places)
`
`
`
`FIG. 3
`
`PETITIONERS
`
`Exhibit 1005, Page 3
`
`PETITIONERS
`Exhibit 1005, Page 3
`
`

`

`Patent Application Publication
`
`Jan. 13, 2011 Sheet 3 of 3
`
`US 2011/0007011 Al
`
`310
`
`712mS
`
`PETITIONERS
`
`Exhibit 1005, Page 4
`
`PETITIONERS
`Exhibit 1005, Page 4
`
`

`

`US 2011/0007011 Al
`
`Jan. 13, 2011
`
`CAPACITIVE TOUCH SCREEN WITH A
`MESH ELECTRODE
`
`BACKGROUND
`
`1. Technical Field
`[0001]
`[0002] The disclosure and claimsherein generally relate to
`touch screens, and morespecifically relate to a touch screen
`having low resistance mesh electrodes to improve theelectri-
`cal characteristics of the touch screen without compromising
`the optical characteristics.
`[0003]
`2. Background Art
`[0004] Touch screens have becomean increasingly impor-
`tant input device. Touch screens use a variety of different
`touch detection mechanisms. One important type of touch
`screen is the capacitive touch screen. Capacitive touch
`screens are manufactured via a multi-step process. Ina typical
`touch screen process, a transparent conductive coating, such
`as indium tin oxide (ITO)is formed into conductive traces or
`electrodes on two surfaces of glass. The conductive traces on
`the two surfaces of glass typically form a grid that can sense
`the change in capacitance whena user’s finger or a pointer
`touches the screen near an intersection of the grid. Thus the
`capacitive touch screen consists of an array of capacitors,
`where a capacitor is created at each crossing of the x and y
`conductive traces or electrodes which are separated by a
`dielectric. These capacitors are charged and discharged by
`scanning electronics. The scanning frequency of the touch
`screen is limited by a resistance/capacitive (RC) time con-
`stant that is characteristic of the capacitors. As the resistance
`ofthe trace becomeslarger andlarger, scanning times become
`proportionately longer and longer. Longer scan times are
`even more problematic as the panel sizes get larger. The larger
`the panel size the longer the traces and the higher the resis-
`tance gets.
`[0005] As mentioned above, in typical capacitive touch
`screens, the conductive traces or electrodes are formed witha
`layer of indium tin oxide (ITO). ITO is used becauseofits
`conductive and transparent qualities. However, the ITO traces
`are not completely transparent. The visibility ofthe electrode
`traces is distracting to the user. It is desirable for the touch
`screen to have the sense electrodes and other traces on the
`touch screen to be substantially invisible to the user, but it is
`also desirable to reduce the resistance of the traces to reduce
`
`the scan times and the performance of the touch screen.
`Increasing the thickness of the ITO layer can reduce the
`electrode trace resistance. However, increasing the thickness
`of the ITO layer sufficiently to decrease the electrode trace
`resistance results in reduced optical performance because the
`thicker ITO layer becomes morevisible.
`
`BRIEF SUMMARY
`
`[0006] The application and claimsherein are directed to an
`improved touch screen with enhancedelectrical performance
`and optical quality. The electrodes on the touch screen are
`made of a mesh of conductors to reduce the overall electrode
`
`resistance thereby increasing the electrical performance with-
`out sacrificing optical quality. The mesh electrodes comprise
`a mesh pattern of conductive material with each conductor
`comprising the mesh having a very small width suchthat the
`conductors are essentially invisible to the user of the touch
`screen.
`
`[0007] The description and examplesherein are directed to
`capacitive touch screens with two substrates for the conduc-
`
`tive sense electrodes, but the claims herein expressly extend
`to other arrangements including a single glass or plastic sub-
`strate.
`
`[0008] The foregoing and other features and advantages
`will be apparent from the following moreparticular descrip-
`tion, andasillustrated in the accompanying drawings.
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`[0009] The disclosure will be described in conjunction with
`the appended drawings, where like designations denote like
`elements, and:
`[0010]
`FIG. 1 is a cross-sectional side view of a capacitive
`touch screen accordingto theprior art;
`[0011]
`FIG. 2 is a cross-sectional side view of a capacitive
`touch screen as described and claimed herein;
`[0012]
`FIG. 3 shows a top view of mesh electrodes on a
`portion of the bottom glass of the touch screen shownin FIG.
`2;
`FIG. 4 shows an enlarged view ofthe cross section
`[0013]
`of the mesh electrode taken on the lines 4-4 of the touch
`screen shown in FIG.3;
`[0014]
`FIG. 5 shows an enlarged top view of the mesh
`conductors of the electrode shownin FIGS. 3 and 4;
`[0015]
`FIG. 6 shows an example of mesh electrodes with a
`diamond shapepattern; and
`[0016]
`FIG. 7 shows an example of mesh electrodes with
`stacked layers.
`
`DETAILED DESCRIPTION
`
`[0017] As claimedherein, the electrodes on a touch screen
`are made of a mesh of conductors to reduce the overall elec-
`
`trode resistance thereby increasing theelectrical performance
`withoutsacrificing optical quality. The mesh electrodes com-
`prise a mesh pattern of conductive material with each con-
`ductor comprising the mesh having a very small width such
`that the conductors are essentially invisible to the user of the
`touch screen.
`[0018] Touch Panel Transparency
`[0019] The optical quality of a touch screen panel can be
`described in terms of transparency, where 100% transparent
`means 100% ofthe light transfers throughthe panel. A typical
`single layer of glass used in a touch screen panelhasa trans-
`parency of about 97%. A typical optical adhesive hasa trans-
`parency of about 99.5%. For a touch panel constructed out of
`twosheets of glass and a single layer of optical adhesive (No
`electrodes on the glass at all), the overall transparency of the
`panel can be calculated as follows:
`Total Panel transparency=0.97*0.97*0,995=93.6%
`
`[0020] As described in the background, a typical touch
`screen panel has a layer of ITO onthe glassto form electrodes
`for sensing the location where the screen is touched. The
`transparency of ITO coated glass with 100 ohm/square ITO is
`~92%. A touch panel constructed out of 100 ohm ITO glass
`with the optical adhesive is therefore about 0.92*0.92*0.
`995=85%. Thinner layers of ITO can give a higher transpar-
`ency, but as discussed above,it is advantageousto reduce the
`electrode resistance for better performance. Thus there is a
`tradeoff between transparencyfor better optical performance
`and resistance ofthe electrode for better touch performance.
`[0021]
`Incapacitive touch panels there are a different meth-
`odologies to measure the capacitive coupling effect when the
`panel is touched. Some methodsuse a separate senseline to
`sense the changein capacitance while the electrodesare being
`PETITIONERS
`
`Exhibit 1005, Page 5
`
`PETITIONERS
`Exhibit 1005, Page 5
`
`

`

`US 2011/0007011 Al
`
`Jan. 13, 2011
`
`driven by the controller. In other methods, the electrodes are
`constantly being switched such that one electrode is driven
`and another electrode is used as the “sense” line. The touch
`panel described above does not show separate sense line.
`However, the mesh electrodes described herein can be used to
`reduce the resistance of touch panel structures, including
`sense lines and electrodes. The claimsherein extendto any of
`these touch panel technologies whether using a separate sense
`line, or using electrodes that are doing double duty as elec-
`trodes and senselines.
`
`FIG. 1 showsa simplified side view of a capacitive
`[0022]
`touch screen 100 accordingto the prior art. The touch screen
`100 hasa top glass 110 and a bottom glass 112. The top glass
`110 is bondedto the bottom glass 112 with a bondinglayer or
`adhesive 114. Between the top glass and bottom glass there
`are row electrodes 116 and column electrodes 118. Only a
`single column electrode 118 is visible in this side view but
`there are multiple column electrodes such that the column
`electrode and the row electrodes form a grid in the manner
`knownin the art. The column electrodes 118 are typically
`formed on the bottom surface 120 ofthe top glass 110 and the
`row electrodes 116 are formed on the top surface 122 of the
`bottom glass 112. The top glass 110 and bottom glass 112
`attached by the adhesive layer 114 form a touch panel 124.
`Below the touch panel 124 is a back light 126 that provides
`light 128 to an LCD 130 that projects an image to the user
`through the touch panel 124. There may be a space (not
`shown) between the backlight 126 and the LCD 130. Sense
`electronics (not shown) connected to the row and column
`electrodes are able to determine the location of touch by a
`user’s finger 132 in the manner knownin the priorart.
`[0023]
`FIG.2 illustrates a cross sectional side view of a
`capacitive touch screen 200 as claimed herein. The touch
`screen panel 200 is similar to that shown in FIG. 1 with
`corresponding structures having the same number as
`described above. Instead of electrodes formed in an ITO layer
`as described above, the touch screen panel 224 has mesh
`electrodes 210 formed of low resistance conductors 212 to
`reduce the trace resistance of the electrode traces. As used
`
`herein, the term “mesh” meansa light-transmissive layer of
`connected strands of opaque material. The mesh strands
`appears woven together similar to a web ornet but are pref-
`erably formed in a layer of material rather than actually
`woven strands. The mesh electrodes 210 are thus an open
`pattern of low resistance conductors 212 that are electrically
`connected together to form an essentially transparent elec-
`trode. The meshelectrodes 210 are preferably formed directly
`on the bottom glass layer 112. The meshelectrodes 210 could
`be made from any suitable low resistance, opaque material
`such as nickel, copper, gold, silver, tin, aluminum andalloys
`and combinations of these metals. The mesh conductors 210
`
`forming the mesh electrode could also be formed with a
`pattern to reduce visibility as described further below. The
`mesh conductors may be formed using methods such aspat-
`tern electrodeplating, pattern electroless plating, plating fol-
`lowedby an etching process, thin film deposition followed by
`photo etching, or an other suitable method to produce the
`structures described herein whether known or developed in
`the future.
`
`FIG. 3 showsa top view of meshelectrodes 210 on
`[0024]
`a portion of the bottom glass 112 of the touch screen 200
`shown in FIG. 2. The mesh electrodes 210 each have a bond-
`ing pad 310 on oneside ofthe electrode in the manner known
`in the prior art. FIG. 3 shows only a small numberofelec-
`
`trodes of a touch panel as an example. A typical touch panel
`would have many such electrodes on the bottom glass 112.
`Sunilarly, a typical touch panel would have many column
`electrodes on the top glass orthogonal to the row electrodes in
`the manner knownin the art. The column electrodes (shown
`in FIG. 2) are preferably also formed as meshelectrodes in the
`same manner as shown for row electrodes in FIG.3. In this
`
`example, the mesh electrodes 210 have a mesh of metal
`conductors formedasa pattern of rectangles 312.
`[0025]
`FIG. 4 showsan enlarged view of across section of
`the mesh electrode 210 on the bottom glass 112 taken on the
`lines 4-4 of touch screen 200 shown in FIG.3. FIG. 5 shows
`
`an enlarged top view of the mesh conductorsofthe electrode
`shown in FIGS. 3 and4. In FIG. 5, the mesh conductors 312
`are more readily apparent as a pattern of rectangles 312.
`Preferably, the conductors of the mesh electrodes 210 have a
`small line geometry or trace width such that they are unde-
`tectable with the naked eye. The line geometries of the mesh
`conductors are preferably less than 0.025 millimeters (mm) in
`width and most preferably about 0.010 mm orless. Further,
`the overall percentage of area of the mesh electrodes conduc-
`tors is substantially small compared to the total area of the
`mesh electrode to enhance the overall transparency of the
`electrodes suchthat the mesh electrode is essentially invisible
`to the naked eye. Preferably the percentage of the electrode
`area that comprises the mesh electrode conductorsis less than
`15% and morepreferably 5% orless of the total area covered
`by the mesh electrode. This meansthat the surface area of the
`meshelectrode conductors 312, as seen from the top as shown
`in FIG. 3, covers 15% or less of the total area of the mesh
`electrode 210, also as seen from the top. The thickness of the
`conductors is notcritical. A thicker mesh conductor material
`will lowerthe resistance of the electrode and improve perfor-
`mance as described above so a thicker mesh conductoris
`preferable depending on the geometries.
`[0026] We will now consider how the mesh electrodes
`affect the resistance and optical clarity of a panel with mesh
`electrodes as shown in FIG.4. In this example, we assume the
`mesh conductors 210 are 0.025 mm wide by 200 mm long by
`0.001 mm thick nickel conductors. The equivalent transpar-
`ency of the glass sheet with the mesh electrodes is a ratio of
`the open glass area to the mesh conductor area. The opaque
`mesh conductors cover about 4.0% of the electrode area, thus
`reducing the transparency of the area of the glass with mesh
`electrodes by about 4.0% (from 0.97 to about 0.93). In the
`non-trace area of the panel the transparency would remain at
`the glass transparency value of 97%. We assume the mesh
`electrodes cover about 30% of the overall glass area leaving
`about 70% of the area not covered by electrodes. Thus, the
`overall effective transparencyto the single sheet of glass with
`mesh electrodes would be 0.97*0.7+0.93*0.3=96%. This
`
`would result in an overall panel transparency of 0.96*0.96*0.
`995=91% (two sheets ofglass with meshelectrodes and adhe-
`sive). Thus our example panel ofmesh electrodes would have
`about the sameeffective optical transparency of a panel made
`with 100 ohm ITO glass but the effective trace resistance
`would be many times lower that the typical 100 ohm ITO
`glass, which will significantly increase performance of the
`touch screen panel.
`[0027]
`FIG. 6 illustrates another example of mesh elec-
`trodes. In this example, the mesh electrodes 210 have an
`outline that is a repeating pattern of diamond shapes 610.
`Other geometric shapesorirregular shapes could also be used
`together to form an electrode depending on the application. In
`PETITIONERS
`
`Exhibit 1005, Page 6
`
`PETITIONERS
`Exhibit 1005, Page 6
`
`

`

`US 2011/0007011 Al
`
`Jan. 13, 2011
`
`this example, the diamond shapes 610 are connected with a
`narrow neck or bridge 612 and the diamonds shapes are
`connected together in a line to form an electrode 210. The
`diamond shaped mesh electrodes 210 comprise a mesh of
`conductors similar to that described above with reference to
`FIG. 3. This meansthat the lines ofthe diamond shape and the
`mesh oflines within the diamondshape in the drawing rep-
`resent conductors and the white spaces in the drawings are
`open space to the glass 112 below in the manner described
`above. The mesh ofconductorsinside the diamond shape may
`be a pattern of squares as shownin the top three electrodes
`310. Many other geometric shapes could be used to pattern
`the mesh of conductors inside the outline of the electrodes to
`
`reduce the visibility of the electrodes. For example, the last
`electrode 210a is shown with a mesh of conductors with a
`circle pattern 614. Similarly, other regular or irregular shapes
`with electrically connected conductors could be used for the
`meshelectrodes.
`
`FIG.7 illustrates a side view ofa stacked layer mesh
`[0028]
`electrode 700 as described and claimed herein.
`In this
`example, a stacked layer mesh electrode 700 comprises an
`electrode with a base layer 710 and a stacked layer 712. The
`stacked layer mesh electrode 700 may comprise different
`layers for different reasons. For example, the base layer 710
`may be a copper, nickel, or aluminum with a goldorsilver
`stacked layer 712 to achieve a lowerresistance. Alternatively,
`the stacked layer 712 may consist ofa layer oflow reflectivity
`material to reduce visibility of the conductive trace. The low
`reflectivity material would be placed on the side ofthe stacked
`electrode 700 facing the user of the touch panel. The low
`reflectivity material may include materials such as magne-
`sium fluoride.
`
`In the examples described above, the mesh elec-
`[0029]
`trodes were formed on a transparent layer of glass as the
`substrate. Touch panels substrates mayalso be constructed of
`other transparent materials such as plastic, polyester, poly-
`carbonate and acrylic. The disclosure and claims herein
`expressly extend to any suitable substrate material, whether
`currently knownor developed in the future.
`[0030]
`In the examples described above, mesh electrodes
`were used for both row electrodes 116 and column electrodes
`118 shownin FIG. 1. In some application it may be advanta-
`geous to only use one mesh electrode. The disclosure and
`claimsherein apply to touch panels with a mixed construction
`of mesh electrodes and conventional electrodes. In a mixed
`construction, either the row electrode or the column electrode
`is a mesh electrode as described above, while the other elec-
`trode is a conventionalsolid electrode.
`[0031] One skilled in the art will appreciate that many
`variations are possible within the scope of the claims. Thus,
`while the disclosure has been particularly shown and
`described above, it will be understood by those skilled in the
`art that these and other changes in form and details may be
`made therein without departing from the spirit and scope of
`the claims. For example, the mesh electrode described herein
`could be used on a touch panel configurations knownintheart
`that use a single glass layer with patterned electrodes sepa-
`rated by a dielectric or on opposing sides ofthe glass.
`
`1. A touch screen comprising:
`a mesh electrode with a total mesh electrode area formed
`
`on a transparent layer, wherein the mesh electrode com-
`prises electrically connecting mesh conductors formed
`ofan opaque conductive materialthat covers less than 15
`percentof the total mesh electrode area.
`
`2. The touch screen of claim 1 wherein the opaque conduc-
`tive material is a metal chosen from the following: nickel,
`copper, gold, silver, tin, aluminum and alloys and combina-
`tions of these metals.
`3. The touch screen of claim 1 wherein the touch screen is
`a capacitive touch screen and the meshelectrodes are formed
`directly on a glass surface.
`4. The touch screen of claim 1 wherein an outline of the
`meshelectrode is a repeating geometric shape.
`5. The touch screen of claim 1 wherein an outline of the
`meshelectrodeis filled with a pattern ofelectrically connect-
`ing mesh conductors.
`6. The touch screen of claim 1 wherein the electrically
`connecting mesh conductors are formed in a pattern chosen
`from the following: rectangles, squares, circles, and irregular
`shapes.
`7. The touch screen of claim 1 wherein the mesh conduc-
`tors are formed of stacked layers of materials.
`8. The touch screen of claim 1 wherein the mesh conduc-
`tors are less than 0.025 mm in width.
`9. The touch screen of claim 1 wherein the mesh conduc-
`tors are less than 0.010 mm in width.
`10. The touch screen ofclaim 1 wherein opaque conductive
`material covers less than 5 percentof the total mesh electrode
`area.
`
`11. A touch screen comprising:
`a first plurality of mesh electrodes formedona first trans-
`parentlayer;
`a second plurality of mesh electrodes formed on a second
`transparentlayer;
`wherein the first and second plurality of mesh electrodes
`havea total electrode area; and
`wherein the first and second plurality of mesh electrodes
`comprises electrically connecting mesh conductors
`formed of an opaque conductive materialthat covers less
`than 15 percent of the total electrode area.
`12. The touch screen of claim 11 wherein the opaque con-
`ductive materialis a metal chosen from the following:nickel,
`copper, gold, silver, tin, aluminum and alloys and combina-
`tions of these metals.
`13. The touch screen of claim 11 wherein the touch screen
`is a capacitive touch screen and the mesh electrodes and the
`first and second transparent layers comprise a material chosen
`from glass, plastic, polyester, polycarbonate and acrylic.
`14. The touch screen of claim 11 wherein an outline of the
`
`meshelectrode is a repeating geometric shape.
`15. The touch screen of claim 11 wherein an outline of the
`
`meshelectrodeis filled with a pattern ofelectrically connect-
`ing mesh conductors.
`16. The touch screen of claim 11 wherein the electrically
`connecting mesh conductors are formed in a pattern chosen
`from the following: rectangles, squares, circles, and irregular
`shapes.
`17. The touch screen of claim 11 wherein the mesh con-
`ductors are formed of stacked layers of materials.
`18. The touch screen of claim 11 wherein the mesh con-
`ductors are less than 0.025 mm in width.
`19. The touch screen of claim 11 wherein the mesh con-
`ductors are less than 0.010 mm in width.
`
`20. A capacitive touch screen comprising:
`a mesh electrode with a total mesh electrode area formed
`
`on a transparentlayer,
`wherein the mesh electrode comprises electrically con-
`necting mesh conductorsthat are less than 0.01 mm in
`PETITIONERS
`
`Exhibit 1005, Page 7
`
`PETITIONERS
`Exhibit 1005, Page 7
`
`

`

`US 2011/0007011 Al
`
`Jan. 13, 2011
`
`width and formed of an opaque conductive materialthat
`covers less than 5 percent of the total mesh electrode
`area;
`wherein the opaque conductive material is a metal chosen
`from the following: nickel, copper, gold, silver, tin, alu-
`minum andalloys and combinations ofthese metals; and
`
`wherein an outline of the mesh electrode is filled with a
`
`pattern of electrically connecting mesh conductors
`formed in a pattern chosen from the following: rect-
`angles, squares, circles, and irregular shapes.
`uf
`uf
`uf
`uf
`uf
`
`PETITIONERS
`
`Exhibit 1005, Page 8
`
`PETITIONERS
`Exhibit 1005, Page 8
`
`