US20050041018A1 - Anisotropic touch screen element - Google Patents

Anisotropic touch screen element Download PDF

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US20050041018A1
US20050041018A1 US10/916,759 US91675904A US2005041018A1 US 20050041018 A1 US20050041018 A1 US 20050041018A1 US 91675904 A US91675904 A US 91675904A US 2005041018 A1 US2005041018 A1 US 2005041018A1
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bus
touch sensitive
bars
position sensor
element
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Harald Philipp
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Atmel Corp
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Harald Philipp
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    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/045Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using resistive elements, e.g. single continuous surface or two parallel surfaces put in contact

Abstract

A touch sensitive position sensor for detecting the position of an object in two dimensions is described. The position sensor has first and second resistive bus-bars spaced apart with an anisotropic conductive area between them. Electric currents induced in the anisotropic conductive area by touch or proximity flow preferentially towards the bus-bars to be sensed by detection circuitry. Because induced currents, for example those induced by drive circuitry, flow preferentially along one direction, pin-cushion distortions in position estimates are largely constrained to this single direction. Such one-dimensional distortions can be corrected for very simply by applying scalar correction factors, thereby avoiding the need for complicated vector correction.

Description

    BACKGROUND OF THE INVENTION
  • The invention pertains to 2-dimensional touch sensing surfaces operable by a human finger, or a stylus. Example devices include touch screens and touch pads, particularly those over LCDs, CRTs and other types of displays, or pen-input tablets, or encoders used in machinery for feedback control purposes.
  • Descriptions of pen or touch input to a machine date back to at least 1908, as embodied in patent DE 203,719 [1].
  • Touch screens and pointing devices have become increasingly popular and common not only in conjunction with personal computers but also in all manner of other appliances such as personal digital assistants (PDAs), point of sale (POS) terminals, electronic information and ticketing kiosks, kitchen appliances and the like. These devices are evolving continuously into lower priced products and as a result, there is a need for ever lower production cost while maintaining high levels of quality and robustness. Capacitive touch screens in particular are prized for their robustness against damage, but suffer from high costs and the need for exotic construction materials.
  • The term ‘two-dimensional capacitive transducer’ or ‘2DCT’ will be used throughout to refer to touch screens, touch sensing pads, proximity sensing areas, display overlay touch screens over LCD, plasma, or CRT screens or the like, position sensing for mechanical devices or feedback systems, or other types of control surfaces without limitation, having a surface or volume capable of reporting at least a 2-dimensional coordinate, Cartesian or otherwise, related to the location of an object or human body part, by means of a capacitance sensing mechanism.
  • The term ‘two-dimensional resistive transducer’ or ‘2DRT’ will be used throughout to refer to touch screens or pen input devices based on purely galvanic principles, and known in the industry generically and primarily as ‘resistive touch screens’.
  • The term ‘2DxT’ refers to elements of either the 2DCT or 2DRT type.
  • The term ‘touch’ throughout means touch or proximity by a human body part or mechanical component of sufficient capacitive signal strength to generate a desired output. In the sense of ‘proximity’, touch can also mean to ‘point’ at a 2DCT without making physical contact, where the 2DCT responds to the capacitance from the proximity of the object sufficient to react properly.
  • The term ‘element’ throughout refers to the active sensing element of a 2DCT or 2DRT. The term ‘electrode’ refers to a connection point at the periphery of the element.
  • The term ‘stripe’ refers to an electrical line conductor that is a component part of an element and which has two ends. A stripe can be a wire. A stripe can have substantial galvanic resistance by intent, whereas a wire has minimal resistance. If the element of which it is a part is physically curved, the stripe would also be physically curved.
  • The term ‘pin cushion’ refers to any distortion of the signal from a 2DCT whether parabolic, barrel, or other form of 2D dimensional aberration.
  • Many types of 2DCT are known to suffer from geometric distortion characterized as ‘pin cushion’ or ‘hyperbolic’ or ‘parabolic’, whereby the reported coordinate of touch is in error due to electrical effects on the sensing surface. These effects are described in more depth in various other patents for example in Pepper U.S. Pat. No. 4,198,539 [2], incorporated by reference. An excellent summary of the known causes, solutions, and problems of the solutions to geometric distortion can be found in a reading of Babb et al, in U.S. Pat No. 5,940,065 [3] and U.S. Pat. No. 6,506,983 [4], incorporated by reference. U.S. Pat No. 5,940,065 [3] describes succinctly the two major classes of correction: 1) Electromechanical methods involving design of or modification to the sensing surface or the connecting electrodes; 2) Modeling methods using mathematical algorithms to correct the distortions.
  • Electromechanical Methods
  • Edge Manipulation of Planar Element: Küpfmüller et al in U.S. Pat. No. 2,338,949 [5] (filed 1940) solve the problem of edge distortion in a 2DRT electrograph using very long rectangular tails in X and Y surrounding a small usable area Küpfmüller takes the further approach of slotting the four tails into stripes; these stripes do not intrude on the user input area but do act to raise the resistance to current flow in an anisotropic manner along sides parallel to current flow. This idea reappears in slightly different form in Yaniv et al, U.S. Pat. No. 4,827,084 [6], nearly 50 years later. Küpfmüller remains the most similar prior art to the instant invention.
  • Becker in U.S. Pat. No. 2,925,467 [7] appears the first to describe a 2DRT electrograph whereby nonlinear edge effects are eliminated via the use of a very low resistance edge material relative to the sheet resistance of the element proper. This method can also be used to construct a 2DCT.
  • Pepper, in patents U.S. Pat. No. 4,198,539 [2], U.S. Pat. No. 4,293,734 [8], and U.S. Pat. No. 4,371,746 [9] describes methods of linearizing a 2DCT by manipulating the edge resistance structure of the element.
  • Talmage, in U.S. Pat. No. 4,822,957 [10] describes a similar edge pattern as Pepper in conjunction with a 2DRT element and a pickoff sheet. Numerous other such patents have been issued using various methods, and the area remains a fertile one for new patents to this day. These methods have been found to be very difficult to develop and replicate, and they are prone to differential thermal heating induced errors and production problems. Very small amounts of localized error or drift can cause substantial changes in coordinate response. The low resistance of the patterned edge strips causes problems with the driver circuitry, forcing the driver circuitry to consume more power and be much more expensive than otherwise. There are a significant number of patents that reference the Pepper patents and which purport to do similar things. The improvements delivered by Pepper etc over Becker are arguably marginal, as at least Becker is easier and more repeatable to fabricate.
  • Edge Resistance with Wire Element: Kable in U.S. Pat. No. 4,678,869 [11] discloses a 2D array for pen input, using resistive divider chains on 2 axes with highly conductive electrodes connected to the chains, the electrodes having some unintended resistance for the purposes of detection, and the detection signal being interpolated from the signals generated between two adjacent electrodes. The unintended resistance causes a slight amount of pin cushion in the response. This patent also describes an algorithmic means to compensate for the slight pin-cushion distortion developed by this technique. The Kable method is not operable with other than a connected stylus, i.e. it is not described as being responsive to a human finger. The Kable patent requires crossovers between conductors and thus needs at least three construction layers (conductor, insulator, conductor).
  • Multiple Active-Edge Electrodes: Turner in U.S. Pat. No. 3,699,439 [12] discloses a uniform resistive screen with an active probe having multiple electrode connections on all four sides to linearize the result.
  • Yoshikawa et al, in U.S. Pat. No. 4,680,430 [13], and Wolfe, in U.S. Pat. No. 5,438,168 [14], teach 2DCT's using multiple electrode points on each side (as opposed to the corners) to facilitate a reduction in pin cushion by reducing the interaction of the current flow from the electrodes on one axis with the electrodes of the other. While the element is a simple sheet resistor, this approach involves large numbers of active electronic connections (such as linear arrays of diodes or MOSFETs) at each connection point in very close proximity to the element.
  • Nakamura in U.S. Pat. No. 4,649,232 [15] teaches similarly as Yoshikawa and Wolfe but with a resistive pickup stylus.
  • Sequentially Scanned Stripe Element: Greanias et al in U.S. Pat. No. 4,686,332 [16] and U.S. Pat. No. 5,149,919 [17], Boie et al in U.S. Pat. No. 5,463,388 [18], and Landmeier in U.S. Pat. No. 5,381,160 [19] teach methods of element sensing using alternating independently driven and sensed stripe conductors in both the X and Y axis, from which is interpreted a position of a finger touch or, by a pickup device, a stylus pen. The construction involves multiple layers of material and special processing. Greanias teaches the use of interpolation between the stripes to achieve higher resolution in both axis. Both require three or more layers to allow crossovers of conductors within the element. Both rely on measurements of capacitance on each stripe, not the amount of cross coupling from one stripe to another. Boie also teaches a special guard-plane.
  • Binstead, in U.S. Pat. No. 5,844,506 [20] and U.S. Pat No. 6,137,427 [21] teaches a touch screen using discrete fine wires in a manner similar to those taught by Kable, Allen, Gerpheide and Greanias. Binstead uses very fine row and column wires to achieve transparency. This patent also teaches the Greanias method of interpolation between electrode wires to achieve higher resolution. The scanning relies on measurements of capacitance on each stripe to ground, not the amount of cross coupling from one to another.
  • Evans in U.S. Pat. No. 4,733,222 [22] also describes a system wherein stripes are sequentially driven in both X and Y axis, using also an external array of capacitors to derive sensing signals via a capacitor divider effect. Interpolation is used to evaluate finer resolutions than possible with the stripes alone.
  • Volpe in U.S. Pat. No. 3,921,166 [23] describes a discrete key mechanical keyboard that uses a capacitive scanning method. There are sequentially driven input rows and sequentially sensed columns. The press of a key increases the coupling from a row to a column, and in this way n-key rollover can be achieved; there is no need for interpolation. Although not a 2DCT, Volpe presages scanned stripe element 2DCT technology. My own U.S. Pat. No. 6,452,514 [24] also falls into this classification of sensor.
  • Itaya in U.S. Pat. No. 5,181,030 [25] discloses a 2DRT having resistive stripes which couple under pressure to a resistive plane which reads out the location of contact. The stripes, or the plane, have a ID voltage gradient imposed on them so that the location of contact on particular the stripe can be readily identified. Each stripe requires its own, at least one electrode connection.
  • Cyclical Scanned Stripe Element: Gerpheide et al, in U.S. Pat. No. 5,305,017 [26] teaches a touch-pad capacitance-based computer pointing device using multiple orthogonal arrays of overlapping metallic stripes separated by insulators. The scan lines are arranged in a cyclically repeating pattern to minimize drive circuitry requirements. A cyclical nature of the wiring of the invention prevents use of this type of 2DCT for absolute position location. The invention is suited to touch pads used to replace mice, where actual location determination is not required, and only relative motion sensing is important. Gerpheide teaches a method of signal balance between two phase-opposed signals at the location of touch.
  • Parallel Read Stripe Element: Allen et al in U.S. Pat No. 5,914,465 [27] teach an element having rows and column scan stripes which are read in parallel by analog circuitry. The patent claims lower noise and faster response times than sequentially scanned elements. The method is particularly suited to touch pads for mouse replacement but does not scale well to higher sizes. Multiple construction layers are required as with all stripe element 2DCT's. The Allen method requires large scale integration and high numbers of connection pins. It interpolates to achieve higher resolution than achievable by the number of raw stripes.
  • In my co-pending U.S. application 60/422837 [28], “Charge Transfer Capacitive Position Sensor” there is described in conjunction with FIG. 12 a method of using individual resistive 1-D stripes to create a touch screen. These stripes can be read either in parallel or sequentially, since the connections to these stripes are independent of one another. Furthermore, in connection with FIG. 6 there is described an interpolated coupling between adjacent lumped electrode elements and an object such as a finger. U.S. application 60/422837 [28] is incorporated herein by reference.
  • Numerical Methods
  • Nakamura in U.S. Pat. No. 4,650,926 [29] describes a system for numerical correction of an electrographic system such as a tablet, using a lookup table system to correct raw 2D coordinate data.
  • Drum, in U.S. Pat. No. 5,101,081 [30] describes a system for numerical correction of an electrographic system such as a tablet via remote means.
  • McDermott in U.S. Pat. No. 5,157,227 [31] teaches a numerical method of correcting a 2DxT employing stored constants which are used during operation to control one or more polynomials to correct the location of reported touch by zone or quadrant.
  • Babb et al, in U.S. Pat. Nos. 5,940,065 [3] and 6,506,983 [4] teach a numerical method to linearize a 2DxT uniform sheet element using coefficients determined during a learn process, without segmentation by zone or quadrant, and on an individual unit basis so as to correct for even minor process variations. The methods disclosed by Babb are complex and involve ‘80 coefficients’ and fourth order polynomials, the coefficients of which must be determined through a rigorous and time-consuming calibration procedure. In tests supervised by the instant inventor, it has been found that 6th order polynomials are required to produce accuracy levels that are acceptable in normal use, and that the result is still highly prone to the slightest subsequent variations post-calibration due to thermal drift and the like. In particular it has been found that the corner connections are extreme contributors to long-term coordinate fluctuations, as they act as singularities with a high gain factor with respect to connection size and quality. Furthermore, the method of numerical correction requires high-resolution digital conversions in order to produce even modest resolution outputs. For example it has been found that a 14-bit ADC is required to provide a quality 9-bit coordinate result. The extra expense and power required of the amplifier system and ADC can be prohibitive in many applications.
  • Technology Summary
  • In all these methods there exists one or a combination of the following deficiencies:
  • Use of exotic construction materials or methods requiring special expertise or equipment to fabricate;
      • Excessive cost compared with simple, galvanic 4-wire resistive touch screens;
      • Require three or more layers to allow orthogonal conductor crossovers;
      • Costly wiring due to the need for many electrode connections;
      • Linearity problems requiring complex algorithms to correct;
      • Need for special linearizing edge patterns which are difficult to control;
      • Not well suited to small or large touch areas;
      • Inability to conform to complex surface shapes such as compound curves; and/or
      • Inability to operate through surfaces more than a few hundred microns thick.
    SUMMARY OF THE INVENTION
  • According to the invention there is provided a touch sensitive position sensor comprising: a substrate defining a touch sensitive platform; first and second resistive bus-bars arranged spaced apart on the substrate; and an anisotropic conductive area arranged between the bus-bars such that currents induced in the anisotropic conductive area flow preferentially towards the bus-bars.
  • a touch sensitive position sensor having a sensing element comprising: a first resistive bus-bar; a second resistive bus-bar displaced from the first resistive bus-bar; and an anisotropic conductive area extending between the first and first resistive bus-bars such that currents induced in the anisotropic conductive area flow preferentially towards the bus-bars.
  • In typical embodiments of the invention, the bus-bars and the anisotropic conductive area have resistances of between 1 kΩ and 50 kΩ. The bus-bars preferably have substantially the same resistance, for example to within ±10%, 20%, 50% or 100%. It is advantageous if the resistance of the bus-bars is less than the resistance between them provided by the anisotropic conductive area.
  • The anisotropic conductive area can be fabricated using a film of molecular substance having anisotropic conduction supported on a substrate, or a plurality of resistive stripes connecting in parallel between the first and first resistive bus-bars, or in other ways.
  • When resistive stripes are used to form the anisotropic conductive area these can be made of sections of resistive wire, or from resistive material deposited on a substrate, for example. Moreover, the width of the resistive stripes is preferably greater than the gaps between them.
  • In some embodiments of the invention, a conductive overlay is provided that is separated from the anisotropic conductive area such that the conductive overlay and the anisotropic conductive area may be brought into contact by externally applied pressure.
  • In some embodiments, the first resistive bus-bar extends between a first and a second electrode and the first resistive bus-bar extends between a third and a fourth electrode, the position sensor further comprising first, second, third and fourth drive channels associated with respective ones of the first, second, third and fourth electrodes, each drive channel being operable to generate an output signal dependent on the resistance between its electrode and the position of the object. For processing the outputs, a processor may be provided that is operable to generate an estimate for the position of the object by comparing the output signals from the drive channels. The processor can be configured to estimate the position of the object in a first direction running between the bus-bars from a ratiometric analysis of the sum of the signals associated with the first and second electrodes and the sum of the signals associated with the third and fourth. It can also be configured to estimate the position of the object in a second direction running along the bus-bars from a ratiometric analysis of the sum of the signals associated with the first and third electrodes and the sum of the signals associated with the second and fourth electrodes. Moreover, the processor is preferably further operable to apply a correction to the estimated position according to a pre-determined distortion associated with the sensing element. Typically, the pre-determined distortion is a one-dimensional pin-cushion distortion.
  • It will be understood that a touch sensitive position sensor according to the invention can be incorporated into a control panel and in turn the control panels can be integrated as part of a variety of different apparatuses.
  • According to the invention there is also provided a touch sensitive position sensor for detecting the position of an object in two dimensions, wherein the position sensor has first and second resistive bus-bars separated by an anisotropic conductive area, the anisotropic conductive area being arranged such that induced electric currents flow preferentially towards the bus-bars. Because induced currents, for example those induced by drive circuitry associated with the sensing element, flow preferentially along one direction, pin-cushion type distortions in position estimates are largely constrained to this direction. Such one-dimensional distortions can be corrected for by applying scalar correction factors.
  • The invention provides a new pattern of conductive material for sensing capacitance behind a plastic or glass panel or other dielectric, which is to be used as a 2DxT, whether in the format of a touch screen or ‘touch pad’.
  • The invention blends some of the features of unpatterned 4-electrode elements together with striped elements and mathematical compensation to arrive at a new classification of anisotropic 2DxT element, or simply, a ‘striped element’. This invention addresses the deficiencies of previous 2DxT approaches and is very low in cost, using as it does conventional processes and materials.
  • Unless otherwise noted hereinafter, the terms ‘connection(s)’ or ‘connected’ refer to either galvanic contact or capacitive coupling. ‘Element’ refers to the physical electrical sensing element made of conductive substances. ‘Electrode’ refers to one of the galvanic connection points made to the element to connect it to suitable driver/sensor electronics. The terms ‘object’ and ‘finger’ are used synonymously in reference to either an inanimate object such as a wiper or pointer or stylus, or alternatively a human finger or other appendage, any of whose presence adjacent the element will create a localized capacitive coupling from a region of the element back to a circuit reference via any circuitous path, whether galvanically or non-galvanically. The term ‘touch’ includes either physical contact between an object and the element, or, proximity in free space between object and element, or physical contact between object and a dielectric (such as glass) existing between object and element, or, proximity in free space including an intervening layer of dielectric existing between object and element. The mention of specific circuit parameters, or orientation is not to be taken as limiting to the invention, as a wide range of parameters is possible using no or slight changes to the circuitry or algorithms; specific parameters and orientation are mentioned only for explanatory purposes.
  • Note my prior patents covering charge-transfer capacitive sensing, particularly U.S. Pat. No. 5,730,165 [32], U.S. Pat. No. 6,288,707 [33], U.S. Pat. No. 6,466,036 [34], U.S. Pat. No. 6,535,200 [35], U.S. Pat No. 6,452,514 [36] and my co-pending U.S. Provisional Application No. 60/422837 [28]. In particular it should be noted that the electronic sensing circuitry and methods described in each of these patents can be used in conjunction with the invention described herein, but, these methods are not the only ones. A variety of capacitive sensing circuits can be used with the invention. Various electrical circuits and sensing methods described in these patents can be employed to drive the electrodes of the invention and to interpret the results.
  • Note also my co-pending U.S. application US 20030132922 [37] which deals with handshadow effects on capacitive touchscreens, and which has a possible application to the invention in a post-processing role for 2DCT's.
  • My co-pending patent application U.S. 60/422837 [28], “Charge Transfer Capacitive Position Sensor” in particular as described in conjunction with FIG. 12 therein, forms a germinal basis for the invention, and whose circuit description and switching methods are particularly well adapted to drive the electrodes of the invention in a 2DCT mode. The invention is a new pattern of conductive material, such as an ink or vacuum deposited material, arranged electrically as a single layer element, with pin-cushion distortion on only one axis. The remaining pin-cushion distortion is easily corrected algorithmically or in hardware, vastly simpler than Babb & Wilson, as will be described below. The element pattern is easily fabricated using known methods and is conformable to complex surfaces such as compound curved cover lenses and the like. The pattern exhibits strong anisotropic conductance characteristics in a core sensing region bounded by peripheral unidirectional resistive conductors.
  • It is one object of the invention to provide for a 2DxT sensing element using common, inexpensive materials and production processes, with anisotropic galvanic conduction characteristics.
  • It is a further object of the invention to provide a 2DxT sensing mechanism having an edge distortion that is readily correctable using simple, computationally inexpensive methods.
  • It is an object of the invention to permit position interpolation so as to achieve the highest possible resolution with the simplest possible pattern.
  • It is another object of the invention to provide a 2DxT element allowing a high positional resolution and low granularity result with relatively coarse raw signal analogue-to-digital converter (ADC) resolution.
  • Another object is to provide a 2DxT element that is less susceptible to thermal drift, and is highly repeatable in the manufacturing process.
  • Another object of the invention is to provide a 2DxT element that either requires a highly simplified ‘learn’ calibration process compared with the prior art, or, calibration via design, or, none at all.
  • Another object is to provide for a 2DCT element having only one required layer of conductive material.
  • A further object is to allow this layer to reside on the rear of relatively thick dielectric cover lenses such as glass or plastic sheet, up to 10 mm in thickness or more, or through air by pointing.
  • A further object of the invention to provide a 2DxT element having relatively simple wiring requirements;
  • Further objects of the invention are to provide for a sensor having high reliability, a sealed surface, low power consumption, and the ability to be controlled and sensed directly using off-the-shelf microcontrollers and non-exotic drive electronics.
  • Further particular and preferred aspects of the invention are set out in the following non-limiting independent and dependent clauses:
      • 1. Apparatus of a type wherein a surface is selectively accessed with respect to positional data, comprising a conductive element having a core with a direction of preferential galvanic conduction.
      • 2. The apparatus of clause 1 wherein the element is bounded by a conductive border
      • 3. Clauses 1 or 2 wherein the element resides on a single layer
      • 4. Clauses 1 or 3 including a plurality of electrodes
      • 5. Any preceding clause including circuitry connected to said element for the purpose of evaluating the location of touch in two dimensions, where the connections are made to the electrodes.
      • 6. Any preceding clause including processing means to correct for pin-cushion distortion
      • 7. Clause 6 wherein the correction is a scalar coefficient.
      • 8. Clause 6 wherein the correction is based on a set of scalar coefficients
      • 9. Clause 6 wherein the correction is based on a formula of the type Pcy ( x , y ) = P Y k 1 X 2 + k 2 X + k 3
      • 10. A method of fabricating an element used for the determination of positional location of touch, whereby the element is made to have anisotropic conductivity with a conductive perimeter.
      • 11. Clause 10 where the element is made from an anisotropic material.
      • 12. Clause 10 including a method to correct for positional distortion
      • 13. Clause 12 wherein the method for correction of distortion is only applied to one axis.
      • 14. Clause 12 wherein the method for correction of distortion is based on scalar multiplication.
      • 15. Any preceding clause whereby the electronic circuitry employs rail-referenced charge-sensing according to any method disclosed in my U.S. Pat. No. 6,466,036 [34].
      • 16. Clause 15 whereby the circuitry comprises a microcontroller.
      • 17. Any preceding clause whereby the element is made from an optically transmissive resistive conductor.
      • 18. Any preceding clause whereby the element comprises a plurality of zones of anisotropic conductance sharing common bus-bars.
      • 19. A touchscreen having an optically transmissive element of anisotropic conductance, affixed to the distal side of an optically transmissive substrate, the proximal side being used for touch, having a plurality of electrodes.
      • 20. Clause 19 whereby the electrodes are connected to a sensing circuit using conductive rubber.
      • 21. Clause 19 or 20 whereby the touchscreen is mounted over an electronic display.
    BRIEF DESCRIPTION OF THE DRAWINGS
  • For a better understanding of the invention and to show how the same may be carried into effect reference is now made by way of example to the accompanying drawings in which:
  • FIG. 1 a schematically shows typical pin-cushion distortion effects found in unpatterned, single element two-dimension transducers made from a resistive film having four corner electrodes and a ‘pickoff’ flexible cover sheet according t the prior art;
  • FIG. 1 b schematically shows the normalization vectors required to linearize the element of FIG. 1 a;
  • FIG. 2 shows a known capacitive or resistive touch screen edge pattern designed to correct pin cushion effects in screens suffering from distortions of the kind shown in FIGS. 1 a and 1 b;
  • FIG. 3 schematically shows a two-dimensional pattern representative of the conductive material used to form a sensing element according to an embodiment of the invention;
  • FIG. 4 schematically shows an electrical circuit representation of the sensing element of FIG. 3;
  • FIG. 5 schematically shows the sensing element of FIG. 3 with the location of a touch identified;
  • FIG. 6 schematically shows a vertical section the sensing element of FIG. 5 taken at the location of the touch;
  • FIG. 7 a schematically shows a row-by-row linearity plot in one quadrant of the sensing element of FIGS. 3 and 5;
  • FIG. 7 b schematically shows the distortion associated with the sensing element of FIGS. 3 and 5;
  • FIG. 8 schematically shows normalization vectors required to linearize the distortion shown in FIGS. 7 a and 7 b;
  • FIG. 9 schematically shows a two-dimensional pattern representative of the conductive material used to form a sensing element according to another embodiment of the invention;
  • FIG. 10 schematically shows a two-dimensional pattern representative of the conductive material used to form a sensing element according to yet another embodiment of the invention;
  • FIG. 11 schematically shows a vertical section the sensing element of FIG. 10 forming part of a resistive touch screen;
  • FIG. 12 schematically shows a two-dimensional pattern representative of the conductive material used to form a sensing element according to yet another embodiment of the invention;
  • FIG. 13 schematically shows the sensing element of FIG. 5 having coupled to drive channels based on charge-transfer methods;
  • FIG. 14 schematically shows a processor arranged to receive signals output from the drive channels of FIG. 13 and to calculate an estimated position of a touch therefrom;
  • FIG. 15 schematically shows a microcontroller connected to four sampling capacitors, the microcontroller and capacitors being configured to provide the sensing channels and processor of FIGS. 13 and 14; and
  • FIG. 16 schematically shows in vertical section a capacitive based position sensor according to an embodiment of the invention arranged over a liquid crystal display so as to create a touch-sensitive screen.
  • DETAILED DESCRIPTION
  • FIGS. 1 a and 1 b show the prior art for 2DxT technology prior to the use of correction hardware or algorithms. The pin cushion effect of FIG. 1 a is well understood. It arises from the current sharing of capacitance-induced flows from the point of touch to the four connection points; the effect is seen in both 2DCT's and in 2DRT 5-wire touch screens which rely on a galvanic version of the same voltage gradients as a 2DCT, but with a flexible ‘pickoff’ cover sheet that deflects and connects to the 2DRT under pressure. The pin cushion effect in these elements increases as the location of touch becomes more distant from all connection points, along an edge; it is at its worst at the centers of the screen edges. As shown in FIG. 1 b, the current flows establish vectors that introduce a graduated distortion with position, resulting in a parabolic curvature of reported location. The vectors are generally non-orthogonal. Instead the angle and magnitude of correction vary wildly depending on the location of touch on the element.
  • Various methods have been devised to counter this effect, notably the use of very low resistance bus-bars around the conductive screen, special edge patterns, multiple connection points to the edges of the screen, and so on, as described above. Discrete conductors, as seen in Binstead, Gerpheide, Kable and Greanias largely solve the problem of pin cushion by using exotic construction methods using multiple layers, expensive circuits, and a high electrode connection count. These types of screens do not scale well with size and are expensive to fabricate. An example of such a method is the edge pattern devised by Pepper which is shown in FIG. 2. This pattern is known to be very difficult to duplicate, suffers from thermal drift, and is relatively expensive to engineer and fabricate.
  • There is a substantial demand for a new capacitive touch screen method that is less expensive and simpler to manufacture than the above methodologies yet is highly robust and suitable for use in hostile environments. In particular there is a need for such devices in the applications of domestic appliances, mobile phones and other hand-held devices, POS terminals, and so on.
  • Embodiments of the invention provide a compromise between the ‘no pin cushion’ but expensive circuitry and fabrication cost of prior-art striped elements, and unpatterned resistive sheet elements. This new hybrid solution produces a pin cushion effect only on one axis, leaving the other axis largely undistorted. Furthermore, as will be seen, the residual pin-cushion distortion has a largely orthogonal and predictable vector which can be compensated using relatively trivial numerical methods, is highly repeatable from unit to unit, and is more immune to differential thermal drift than the prior art.
  • In FIG. 3 is shown a pattern representative of the conductive material used in a sensing element according to an embodiment of the invention. The diagram shows a single conductive element on one layer having four electrodes 301, 302, 303, and 304. Two relatively low resistance bus-bars 305 and 306 traverse from 301 to 302, and 304 to 303 respectively. A plurality of stripe conductors 310 traverse from bus-bar 305 to 306, numbering at least two but typically 3 or more. Two of these stripes traverse from the ends of each bus-bar to the other, thus forming a fully bounded surface. The end stripes can also be considered to be bus-bars, but as they can optionally have a higher path resistance than the horizontal bus-bars shown, they remain unique and thus will be called stripes throughout.
  • The element of the invention can alternatively be viewed as having a core area characterized by anisotropic conductivity with a surrounding, bounding border made from linear conductive segments. The purpose of the stripes is to force anisotropic galvanic flows within the core area. Once the current flows reach the boundary paths, they are finally led to the electrode connections.
  • The number of stripes 310 appropriate for a design depends on the width of the element in relation to the size of the object being sensed, as will be discussed below. Wires 312 a-d connected to the electrodes connect the element to a drive/sensing circuit in the case of a 2DCT. In the case of a 2DRT wires 312 a-d are connected to a drive circuit, the sensing function coming from a flexible user-depressed cover sheet as shown in FIG. 11.
  • FIG. 10 shows another pattern embodying the invention. This pattern is substantially the same as the pattern of FIG. 3 except that the stripes are separated by thin slits (i.e. the stripes are relatively wider than those shown in FIG. 3), so that the element is principally coated with conductive material and only a very small percentage—the slits—is uncoated. This configuration is more suitable for 2DRT use as described further below, but can also be used in 2DCT applications. One advantage of this for 2DCT use is that the stripes have larger surface areas than in the FIG. 3 example, so that the capacitive coupling from finger to element is enhanced. One disadvantage of this is that the total resistance from bus-bar to bus-bar is lower for a particular sheet resistance, which will tend to exacerbate the pin cushion effect as described below.
  • The relative resistances of the stripes and bus-bars in FIG. 3 as tested are about 40K ohms for the bus-bars, and 160K ohms for the stripes, although in practice these figures are only for guidance and they are not limiting to the invention. The use of higher resistance value stripes than bus-bars is helpful to limit pin cushion effects, but since pin cushion is easily correctable numerically anyway, almost any combination of values will work to varying degrees of satisfaction. It is a considerable attraction of the invention that it is usable with elements having a high resistance, as such an element requires lower cost and lower power drive and sensing electronics.
  • FIG. 4 shows a lumped model of typical embodiments of the invention. Bus-bars 305 and 306 are composed of lines with a resistance from about 1K to 50K ohms, and ideally are matched to within 10% of each other. Stripes 310 are composed of resistive lines of about 5 to 10 times more than the resistance of the bus-bars. There are 9 stripes shown in FIG. 4. Corner electrodes 301, 302, 303, and 304 are used to connect the element to drive/sensing electronics, either capacitive sensing drivers for a 2DCT or galvanic drivers in the case of a 2DRT. Each stripe and bus-bar has some stray background capacitance 401 to circuit ground. Stripes have mutual capacitance 404 between neighbors. Such background capacitances are benign in nature and have been show to have no effect on the performance of the invention. These capacitances do not have to be equal or balanced for the invention to work, as the element obeys the physics of superposition, and such parasitic values are easily calibrated away by the drive electronics as will be described below.
  • Shown is a capacitance Ct, 402, at position 403 due to a touch in 2DCT mode. The invention is fully tolerant of the magnitude of Ct, in that it allows the use of circuitry and/or algorithms that responds ratiometrically to the four electrode signals to derive a position independent of the magnitude of Ct. In 2DRT mode, the coversheet picks off a gradient potential, usually using time-multiplexed drive signals to the four electrodes upon galvanic connection from the coversheet to the element under the pressure of touch.
  • In 2DCT mode it is also possible to have a touch between stripes and to interpolate the location of touch. FIG. 5 shows the element with a touch capacitance geographically located at 403 due to finger (not shown). FIG. 6, in which is shown a cross section of the invention attached to a substrate such as glass. The capacitance 603 due to touch of finger 605 is split into three smaller parts, Ct1, Ct2, and Ct3 as shown in FIG. 6, whose ratio depends on the relative location of the touch among the stripes 310 a,b,c. In FIG. 6 of my co-pending U.S. application 60/422837 [28] is shown an interpolation between two adjacent electrodes connected by a resistance. The interpolation of touch in the instant invention operates in exactly the same manner among stripes in X, but also occurs along each stripe in the Y axis (not shown). The separating resistance in X is the path starting on each stripe with each Ct 603, back through the bus-bars to the other stripe. The interpolation in the X direction is proportioned according to the resistance of the short segment of bus-bar resistance connecting the two Y stripes, as a percentage of the total electrical bus-bar ‘length’. The resistance of the stripe itself is not of consequence for resolving X location, since the ends of each stripe are driven to equipotentials in most 2DCT drive circuits described in the literature, and certainly when driven by the charge-transfer circuits described in my various earlier patent publications. Thus, if the stripes are spaced apart by 10% of the total bus-bar length, then the opportunity for interpolation will be 10% of the X dimension.
  • Note that the element of FIG. 5 could be rotated through 90 degrees and the above discussion would have been in regard to the Y dimension. There is no preferred angle of orientation of the element of the invention with regard to detection and location of touch. The discussions and formulae noted below are based on an assumption of convenience i.e. that the stripes are aligned in a vertical, Y orientation; however, rotation of the element through 90 degrees would provide identical physical operation and the equations would still hold albeit translated through 90 degrees. Specificity in regard to the orientation in this patent is not intended except as a matter of explanatory convenience and should not be held to be limiting in any way.
  • The measurement circuitry, well described in the literature from a variety of inventors but preferably of any type as disclosed by the inventor in his U.S. Pat. Nos. 6,288,707 [33], 6,466,036 [34] and co-pending application 60/422837 [28], is used by standard connection to the four corner electrodes 301, 302, 303, and 304. The measurement circuitry comprises four drive channels coupled to respective ones of the electrodes shown in FIG. 3 with each channel being operable to generate an output signal dependent on the resistive path length between its electrode and the position of the touch. While other methods might use other formulas, the preferred method of calculation of the position of touch is an adaptation of the one disclosed in my co-pending application 60/422837 [28]. In this method the four corner signals are calibrated at some time to determine a baseline reference level of signal for each corner. The calibration step can occur once, for example during design, on the production line, or at each power-up event, or through a method that determines when the element is not being touched. Drift compensation can be applied as it is known from several of my prior patents and the datasheets of products from Quantum Research Group Ltd (UK), such as the QT110 device [38].
  • To compute the position of touch along X (i.e. the horizontal direction shown in FIG. 3) using the element of FIG. 3 the signals are processed according to the following steps assuming that the real time acquired signals associated with the four electrodes 301, 302, 303 and 304 are respectively S301, S302, S303, and S304, and the baseline reference levels are R301, R302, R303, and R304, respective to each corner:
  • 1) Sum the references and signals in X:
    RX′=R 301+R 304 (sum of left references)
    RX″=R 302+R 303 (sum of right references)
    SX′=S 301+S 304 (sum of left signals)
    SX″= S 302+S 303 (sum of right signals)
  • 2) Compute the delta signals in X, i.e. ΔSigX′, ΔSigX″:
    ΔSigX′=SX′−RX′
    ΔSigX″=SX″−RX″
  • 3) Compute the ratio Px indicative of position in X:
    Px =ΔSigX″/(ΔSigX′+ΔSigX″)
    where the Px is in range of 0 . . . 1, ‘0’ being the left edge, ‘1’ the right edge.
  • The formula for X can be re-expanded to: P x = S302 + S303 - R302 - R303 S301 + S302 + S303 + S304 - R301 - R302 - R303 - R304 ( Equation 1 )
  • To compute the position of touch along Y using the element of FIG. 3 the signals are processed according to a formula similar to that indicated above:
  • 1) Sum the references and signals in Y:
    RY′=R 303+R 304 (sum of bottom references)
    RY″=R 301+R 302 (sum of top references)
    SY′=S 303+S 304 (sum of bottom signals)
    SY″=S 301+S 302 (sum of top signals)
  • 2) Compute the delta signals in Y, i.e. ΔSigY′, ΔSigY″:
    ΔSigY′=SY′−RY′
    ΔSigY″=SY″−RY″
  • 3) Compute the ratio Py indicative of position in Y:
    Py=ΔSigY″/(ΔSigY′+ΔSigY″)
    where the Py is in range of 0 . . . 1, ‘0’ being the bottom edge, ‘1’ the top edge.
  • The formula for Py can be re-expanded to: P y = S301 + S302 - R301 - R302 S301 + S302 + S303 + S304 - R301 - R302 - R303 - R304 ( Equation 2 )
  • The complete, reported but uncorrected or ‘raw’ estimated position is thus (Px, Py).
  • The above equations are examples only, and other equations used in conjunction with other screens may also generate a comparable result.
  • In FIG. 6 is shown a touch 601 over a plurality of stripes creating a distribution of Ct over said stripes. The resultant charge flows in the element set up an areal distribution of Ct couplings across multiple stripes, roughly in proportion to the adjoining surface areas of touch and stripes. The principle of superposition applies (as it does in any sheet element) and the resultant determination of position will be properly weighted and hence located to a far higher effective resolution than the number of stripes would seem to indicate. This effect is used to greatly improve resolution in many other stripe based 2DCTs, for example in U.S. Pat. No. 4,733,222 (Evans) [22], but whereas Evans uses numerical interpolation, the instant invention uses the physical properties of distributed capacitance among multiple stripes to achieve the same thing, without the need for further computation or for need for individual electronic addressability of each stripe. The interpolation is intrinsic to the element itself. This is an effect previously known to occur in 2DCT resistive sheet elements.
  • FIG. 7 a shows the calculated position along the X axis by Y row of touch as calculated from the corner electrode signals according to Eqns 1 and 2 above for a series of touches made at different X locations between X=0.5 (center) and X=1 (right edge) along nine rows R0 to R8 corresponding to nine Y locations between Y=0.5 and Y=1. FIG. 7 b schematically represents the distortion over all quadrants of the sensing element. A finger touching the element, whose circumference of contact encompasses a fractional number of stripes, shows no cogging or nonlinearity in X worth noting when dragged orthogonally to the stripes. This can be seen more graphically in FIG. 8 which shows a plot of the correction vectors for 7 rows cutting across the stripes in X. At no place is there a non-orthogonal, non-vertical correction vector.
  • This remarkable result comes about because the stripes restrict core galvanic current flows to the stripes, which lie only along the Y axis; this restriction prevents non-orthogonal current vectors anywhere in the element. Once the current flows reach a bus-bar from a stripe, the flow rotates 90 degrees and heads towards the two nearest corner electrodes. It is only at this stage that the currents can be diverted down adjacent stripes to electrodes on the second bus-bar. This creates the pin cushion effect along the bus-bars.
  • FIGS. 7 a, 7 b, and 8 show that in the Y axis the distortions are linear and can be corrected using a simple scaling factor which has a dependency on X. For each position in X, there exists a single scalar (non-vector) correction factor which can be use to arrive at a corrected position of touch in Y:
    Pcy (x.v) =P Y
    Figure US20050041018A1-20050224-P00001
    (x)   (Equation 3)
  • Where Py is the raw reported position in Y, Pcy(x,y) is the corrected position for Y as a function of X and raw Y, and
    Figure US20050041018A1-20050224-P00001
    (x) is a correction factor unique to each position in X for which a correction factor is sought. The coefficients
    Figure US20050041018A1-20050224-P00001
    (x) need only be solved for in any one quadrant (for example the quadrant represented in FIG. 7 a), and the results mirrored for the other 3 quadrants. The fact that there is no non-orthogonal component to the correction, and that a single factor
    Figure US20050041018A1-20050224-P00001
    (x) applies to any signal in Y(x), simplifies computations by two orders of magnitude over Babb so that very rapid compensation can be performed using slow, cheap microcontrollers for example costing under US$0.50. Furthermore the simplicity of the distortion and the correction method imply that the element is also more stable under fluctuating temperature or electrical conditions and is more repeatable to manufacture. Unlike Babb, the correction of the element does not require multiple trials to allow curve fitting. So long as the strip-to-bus-bar resistance ratio is repeatable (absolute stability is not required), the factors
    Figure US20050041018A1-20050224-P00001
    (x) will be the same from one unit to the next. Inconsistencies from unit to unit will have only a limited effect on the error term in reported touch location, and errors on one axis will create only highly attenuated errors on the other axis. The element of the invention generally isolates error terms between X and Y, a non-trivial beneficial effect compared with the prior art.
  • The simplicity of the instant invention should be compare with the ‘80 coefficients’ and fourth order polynomials required for Babb, the coefficients of which must be determined though an extensive calibration procedure. The instant invention may require only single point calibration, or in most cases no calibration at all, as element distortions are simple, predictable, and repeatable from unit to unit.
  • The
    Figure US20050041018A1-20050224-P00001
    (x) correction factors can be applied by means of a lookup table with interpolation to achieve a simple, fast correction. The correction factor
    Figure US20050041018A1-20050224-P00001
    (x) can also be computed mathematically using the simple quadratic equation: ( X ) = 1 k 1 X 2 + k 2 X + k 3 ( Equation 4 )
  • Leading to the complete equation for Y correction: Pcy ( x , y ) = P Y k 1 X 2 + k 2 X + k 3 ( Equation 5 )
  • Where k1, k2 and k3 are coefficients that depend on the curvature of pin-cushion distortion, and X is the absolute magnitude of the position along the X axis starting from center-screen and moving in either the left or right direction. This quadratic equation was derived from simulation models and is accurate to better than 1%. It does not account for gross material nonlinearity which can be compensated for using secondary methods if required. The equations are dependent on resistance ratios between the bus-bars and the stripes as well as the geometric proportions of the element. The equations are unaffected by absolute resistance values.
  • The analysis supra applies equally to a 2DCT or a 2DRT. A 2DRT generally operates in ‘reverse’ to a 2DCT in that the element is only driven by signals, which are then picked off by a coversheet using a 5th electrode connection for analysis purposes. The electrodes on the element proper are usually driven in a time-multiplexed mode so as to allow for unique signals to be picked up in alternating X and Y directions. For example the two left electrodes are first grounded, and the two right ones driven to a fixed and identical potential; the cover sheet is sampled to obtain a raw X position. The bottom electrodes are next grounded, and the top electrodes connected to a fixed and identical potential; the cover sheet is sampled to obtain a raw Y position. The process is repeated continuously, and a sample is declared valid only if the cover sheet is sensed to be in galvanic contact with the element. This is a potentiometric pickoff method, well described in the patent literature. Other 2DRT sampling methods are possible and the sequence noted in this paragraph should not be considered a preferred method, nor is the sampling method an object of the invention.
  • Equation 5 needs only a set of solutions in one quadrant, with the results mirrored for the other 3 quadrants. This is demonstrated in FIGS. 7 a and 7 b. FIG. 7 a shows the distortion in the top right quadrant; this pattern is mirrored in the other three quadrants to create the pattern of 7 b.
  • Handshadow; Zonal 2DCT Element
  • The phenomenon of 2DCT handshadow is described in my co-pending U.S. application US20030132922 [37] and in U.S. Pat No. 5,457,289 [39]. Screens that are ‘mobile phone size’ such as 60×60 mm, will not generally suffer sufficiently from handshadow to warrant corrective action.
  • However, if desired one way to reduce the effects of handshadow is described in my aforesaid U.S. application, US20030132922 [37], incorporated herein by reference.
  • A second method involves essentially repeating the element of the invention a second time as shown in FIG. 9. However, as can be seen from FIG. 9, this can be achieved by effectively sharing a bus-bar to reduce associated component counts. When the pattern is excited by driver/sensor circuitry on the 6 nodes (i.e. electrodes) 301, 302, 301 a, 302 a, 303 and 304 as shown, the element is effectively divided up in a way that allows it to be sensed in two different zones, top and bottom. Sensing within these zones is as described above. As handshadow capacitance occurs primarily below the point of touch, a touch in the upper zone will cause handshadow primarily in the lower zone, where it can be ‘processed away’ by simply ignoring the signals from said lower zone. There is very little cross-coupling of handshadow currents between zones.
  • Larger screens would make use of even more of these zones, to a number appropriate to the vertical size of the entire element and according to the severity of the problem.
  • 2DRT Application
  • FIG. 10 shows an element having slits between stripes. Such a method of separating stripes is particularly useful for 2DRT usage, where a cover sheet is deflected to contact the element at a small point. If the point of contact is smaller than the gap between stripes 310, it can be that the coversheet fails to pick up a potential and the contact fails.
  • FIG. 11 shows a resistive screen according to the invention, wherein a cover sheet picks off a galvanic potential from the slit stripes of FIG. 10 when bent inwards via touch or via a stylus. The element of FIG. 11 is exactly as described above for a 2DCT, but the operating mode is according to various 5-wire screen modes as discussed in other patents and in the open literature. Normally the cover sheet is held apart from the element via tiny ‘microbump’ spacers (not shown), as is well known in the art.
  • Minimalist 2DCT
  • FIG. 12 shows a minimal 2DCT case, where there are 2 bus-bars and two stripes, all on the periphery of an element. The element is of a size not significantly larger than the object being sensed, so that the signal levels in the middle do not significantly diminish due to distance from object to each conductive member. This example operates without measurable pin cushion as the impedances of the stripes and bus-bars are many orders of magnitude lower than the capacitive coupling impedance from object to any strip or bus-bar. In this minimal case, the stripes and bus-bars can have the same value or wildly differing values with minimal observable effect on resolution or linearity. If the element of FIG. 12 is for use by a human finger, the element should preferably be no more than 4 times as wide or high as the diameter of a finger in order to provide reasonable signal strengths. The element of FIG. 12 can be used to create a ‘mini mouse pad’ or pointer control, for example for use by those with minimal appendage mobility, whereby very small motions of a fingertip or other appendage control an appliance or GUI.
  • Point-Screen 2DCT Operation
  • The 2DCT element is suited to use in a ‘point mode’ where the user simply points at the screen. The easily correctable pin cushion and use of a single element mean that fields are not localized to short distances. As a result, the invention can be used as a ‘point screen’ device with reasonable accuracy in most menu-based graphical interfaces.
  • This mode of operation can be extremely beneficial in hygiene applications such as in hospitals, but also in ordinary consumer usage modes to prevent screen smudging.
  • 2DCT Drive Circuitry
  • Refer now to FIG. 13, wherein is shown preferred (but not essential) drive circuitry for the 2DCT application of the invention. This circuit is of the same type as shown in my co-pending U.S. application 60/422837 [28] but applied to all 4 electrodes (or 6 electrodes in the case of FIG. 9, etc). The repeated switching of switches 1302, 1303, 1304 at locations A, A′, A″, A″′, B, B′, B″, B″′, and C, C′, C″, C″′ are performed simultaneously at each electrode so as to inject and measure charge using four capacitors, also referred to as sampling capacitors, Cs, 1305, at equal moments in time. This is performed via switch controller 1307. Signal outputs are the tabulated number of switching cycles for each electrode required to exceed a threshold voltage Vt, as determined by a voltage comparator 1301. The tabulation of cycle counts for each electrode is performed by four counters at 1306.
  • The operation of this circuitry is explained more fully in my U.S. application 60/422837 [28], incorporated by reference herein.
  • The invention can alternatively employ any of the switching sequences and topologies as described in my U.S. Pat. No. 6,466,036 [34], incorporated herein by reference.
  • Signal processing circuitry is shown in FIG. 14, wherein the four electrode signals are input to the processing circuitry which in turn computes a coordinate result. A logic block, microcontroller, or other hardware or software is used to perform the calculations necessary to achieve the desired output. The block of FIG. 14 is usually a part of another system, such as a personal computer, process controller, appliance and so on, and the output may be only an intermediate result in a larger process.
  • FIG. 15 shows a preferred embodiment of the invention wherein a single microcontroller 1501 performs the switching functions of FIG. 13, plus performs the signal processing of FIG. 14. The switching functions can be performed in software on a conventional I/O port, or with an on-chip hardware capacitive conversion peripheral. Signal processing is performed in software to achieve the desired coordinate output. This output could be a mere intermediate result used to control a larger process, and the output shown may only exist as numbers inside the chip.
  • Alternatively the invention can use any capacitive or resistive sensing circuit described in literature. The gradient response of the element is normally the same regardless of the type of drive circuitry. The invention is not reliant on any one acquisition method.
  • Materials, Fabrication
  • The 2DxT element is preferably made of a clear conductor of suitable resistance on the back of a glass or plastic sheet covering the display, if a touchscreen, or over a suitable dielectric substrate if a mousepad, etc.
  • As described in various other patents, the need for low-R bus-bars (under about 200 ohms end-to-end) on the edges causes all manner of driving, power, stability, and repeatability issues. It is highly desirable to use materials with a much higher resistance than currently in widespread use. Most ITO (Indium Tin Oxide) layers such as those produced by CPFilms, USA, or when custom-sputtered onto a surface, have resistances around 300 ohms per square. It is highly desirable to elevate this resistance to the neighborhood of 500 to 2000 ohms per square, so that the stripe and bus-bar resistances can be made in the region of 25K ohms and up from end to end.
  • One method of increasing bus-bar and stripe resistance from low resistance materials is to use a meandering path or zig-zag pattern so as to increase track length. Conventional low-resistance ITO or Tin-Oxide coatings can be etched or patterned to have intentional voids (‘Swiss cheese’ approach), thus raising the resistance. The stripes and bus-bars can also be made suitably thin so that the resistance is high enough to be more optimal.
  • Ideal materials however will have an intrinsic resistance of about 500 to 1,000 ohms per square or more, or can be modified to become so. Agfa's Orgacon™ conductive polymer is one material that has such a high intrinsic resistance and is also clear, making it usable in touch-screens over displays. A particularly low cost material is carbon based ink, well known in the electronics trade, however being opaque this material is better suited for tablet or mousepad applications.
  • The above being said, there is no requirement for any particular element resistance value, and the driving circuitry can be adapted to almost anything with varying degrees of difficulty. In theory the only requirement is that the elements have a non-zero resistance. However the bus-bar resistances should preferably be comparable or lower in value than the aggregate parallel value of the stripes in order to reduce Y-axis pin cushion. A greater number of stripes would generally mean a higher resistance per stripe to achieve the same effect, the pin cushion being related to the total bridging resistance between stripes, the bridging resistance being the parallel equivalent value of the stripes. Stripes located towards the center of the bus-bars have a disproportionate effect on pin cushion.
  • Patterning of the element into bus-bars and stripes can be via vapor deposition using a suitable stencil to prevent unwanted areas of coating, or via silk screening to create the desired pattern, or via pad-printing, or via laser scribe or chemical etching or chemical reaction, or any other process which can create a patterned layer. In the case of conductive polymer Agfa Orgacon™, the pattern can be created by using sodium hypochlorite to force areas to become non-conductive via chemical reaction without actual material removal.
  • Fabrication can entail the use of normal touchscreen or touchpad methods such as vapor deposition of appropriate materials onto a glass sheet placed in front of a display.
  • In-mold decorating (“IMD”) entails the use of a graphic sheet or layer placed inside the injection mold or cast prior to the introduction of fluid plastic. Once molded, the layer becomes an integral part of the resultant plastic piece. In the case of a 2DCT, a conductive element of the type according to the invention is placed in the mold for a display cover; when injected, the conductive layer becomes fused to one side of the cover. In this way complex cover shapes, including those having compound curves, can be created which include an integral 2DCT at extremely low cost.
  • Electrode connections can be made via wires bonded to the corners, or via conductive rubber pillars, or using metal springs, etc. Conductive rubber is a method of choice for very low cost connection from an underlying PCB containing the driver circuitry. FIG. 16 shows such a construction method in cross-section. Display 1601 is viewed through cover lens 1602 and sensing element 300. Element 300 is connected via at least four corner electrodes through conductive rubber posts, of which two 1603 a , 1603 b are shown, to PCB 1604. The entire assembly is placed under compression via screws, clamps or other fastener system (not shown) so that the rubber posts are compressed and thus forced to make contact between PCB 1604 and element 300.
  • The element can also be fabricated from molecular substances having anisotropic conduction. For example, a conductive polymer can be envisioned having conductivity that is much better in one direction than another. Such materials based on nanostructures have been described in the literature, for example in literature from Helsinki University of Technology.
  • 2DxT Stripe Weighting
  • One embodiment of the invention weights the stripes so that the ones near center-screen are either spaced further apart or have a higher resistance or both. The effect of this is to reduce the amount of inherent pin cushion. However, tests have shown that while this in fact is what happens, it also means that there will be a loss of signal in the center of the element, and/or there will be drive problems through the resultant higher resistance and lower finger coupling to neighboring traces. In practice this approach is not deemed to be efficacious, and is mentioned here only for completeness.
  • 2DCT Acquisition Manipulation
  • Problems associated with 2DCT's include interference from outside electrostatic or radio sources having a frequency at the operating frequency of the element, or some harmonic thereof. These problems can be attenuated by using a modulated operating frequency for the signal acquisition so as to reduce or prevent signal-noise aliasing or beating. This can involve the use of frequency hopping, chirps, or pseudo-random frequency modulation. These methods are known as ‘spread-spectrum’ modulation.
  • Post processing can include the use of majority vote filtering, median filtering, averaging, and so on to reduce the residual effects of noise that are already attenuated by means of the frequency modulation.
  • Low frequency interference can be caused by local mains fields and so on. This form of interference can be attenuated by synchronizing the acquisition to the interfering source, for example 50 or 60 Hz, as described in the datasheet for the Quantum Research Group Ltd (UK) QT310 device [40].
  • 2DCT Driven Shield
  • The element is compatible with driven shield methods to reduce interference from LCD displays, VFD switching, etc. This entails the use of a conductive plane behind the element positioned between the element and the interfering source. A drive shield can also protect against signal disturbance from motion behind the element. Driven back-shields are commonly used in the construction of 2DCT's.
  • 2DCT Wake-Up
  • In many applications it is desirable to have a ‘wakeup’ function, whereby the entire device ‘sleeps’ or is in some quiescent or background state. In such cases, it is often desirable to have a wake signal from mere proximity of a human body part some distance away.
  • The element can be driven as a single large capacitive electrode without regard to position location, while the unit is in the background state. During this state the electronic driver logic looks for a very small change in signal, not necessarily enough to process as a 2D coordinate, but enough to determine that an object or human is in proximity. The electronics then ‘wakes up’ the overall system and the element is driven so as to become a true 2DCT once again.
  • Tablet, Mouse Pad Usage; Injection Mode
  • The element of the invention in 2DCT mode is suitable as a mouse pad, or as a tablet type input device. In these roles, there is no need for optical transparency. A stylus can be used with the element either to pick up a radiated electric field from the element, or to inject a signal into the element, or to act as a human finger.
  • In injection mode, the element of the invention merely operates in reverse. A signal from a tethered pen is injected capacitively into the element in a region surrounding the point of contact. The signal is then apportioned ratiometrically to the four corner electrodes, from whence it can be picked up and conveyed to a measurement circuit of almost any type already described in literature and then processed to create an indicative result. The pin cushion result operates in substantially the same way in injection mode as it does in a 2DRT or 2DCT mode; the vector gradients are the same.
  • 2DxT Uncorrected Mode
  • Many applications do not require linearization of the result. These are principally those applications involving human interfaces of low resolution, for example for menu button sensing and the like. In such applications, the element and related signal acquisition circuitry can dispense with the linearization step and simply generate the raw output. Additional system logic would interpret 2D coordinate boundaries as being touch buttons, the boundaries being defined at the time of software development.
  • If the ratio of stripe-to-bus-bar resistance is high enough, the accuracy of the raw processed result may be acceptable for direct use. For example, if the resulting coordinate error of an element is only 5% but is repeatable, the element may be perfectly suitable for uncorrected menu button detection over a display where the buttons do not occupy less than 10% of the height of the element. If the buttons are principally located near the horizontal centerline of the element, or along the left or right sides, the distortion could be negligible and if so, no linearization correction need be applied.
  • Summary The invention is at its basic reduction, an element whose purpose is to provide for an improved form of 2D sensing device via anisotropic conduction, plus, optionally, a method to correct the distortions of the raw computed coordinate result. The mode of operation (including but without limitation, galvanic or capacitive modes), the use to which it is put, and whether it is used as a receiver of signals from a stylus or a sensor of passive touch is not of prime importance to the invention. What is important is the anisotropic structure of the element and the form of positional error it produces, and the optional methods disclosed herein for correcting the error.
  • An important aspect of sensing elements of embodiments of the invention is that they can be made as a single-layer having a core that conducts well galvanically in a first predetermined direction, but suppresses conduction in a second direction orthogonal to the first, i.e. it has anisotropic conductivity, plus, the core is bounded by a resistive border to make the whole element. The element furthermore has four electrodes in the corners and which are driven and/or sensed by an electronic circuit to create a resulting output indicative of touch position.
  • There are many variations possible as will become evident to those skilled in the art, involving various combinations of detection methods or switch sequences outlined specifically herein. The methods disclosed herein can be combined with other methods as taught in any number of my prior patents including methods for drift compensation, calibration, moisture suppression using short switch closure times, and the like. Particular note should be made of the various possible combinations of features disclosed in my own prior art involving capacitive sensing methods, all of which are incorporated herein by reference; also note the capacitive products as described in the datasheets of Quantum Research Group Ltd (UK), many of which have features germane to the instant invention.
  • It is also possible to warp the invention into unusual shapes as disclosed by Pepper. Such transformations may prove useful in object position sensing for example in industrial settings, where location along a cylinder, sphere, or other curved surface might be important.
  • It will be appreciated that although particular embodiments of the invention have been described, many modifications/additions and/or substitutions may be made within the spirit and scope of the present invention.
  • REFERENCES
    • [1] DE 203,719
    • [2] U.S. Pat. No. 4,198,539
    • [3] U.S. Pat. No. 5,940,065
    • [4] U.S. Pat. No. 6,506,983
    • [5] U.S. Pat. No. 2,338,949
    • [6] U.S. Pat. No. 4,827,084
    • [7] U.S. Pat. No. 2,925,467
    • [8] U.S. Pat. No. 4,293,734
    • [9] U.S. Pat. No. 4,371,746
    • [10] U.S. Pat. No. 4,822,957
    • [11] U.S. Pat. No. 4,678,869
    • [12] U.S. Pat. No. 3,699,439
    • [13] U.S. Pat. No. 4,680,430
    • [14] U.S. Pat. No. 5,438,168
    • [15] U.S. Pat. No. 4,649,232
    • [16] U.S. Pat. No. 4,686,332
    • [17] U.S. Pat. No. 5,149,919
    • [18] U.S. Pat. No. 5,463,388
    • [19] U.S. Pat. No. 5,381,160
    • [20] U.S. Pat. No. 5,844,506
    • [21] U.S. Pat. No. 6,137,427
    • [22] U.S. Pat. No. 4,733,222
    • [23] U.S. Pat. No. 3,921,166
    • [24] U.S. Pat. No. 6,452,514
    • [25] U.S. Pat. No. 5,181,030
    • [26] U.S. Pat. No. 5,305,017
    • [27] U.S. Pat. No. 5,914,465
    • [28] U.S. 60/422837
    • [29] U.S. Pat No. 4,650,926
    • [30] U.S. Pat. No. 5,101,081
    • [31] U.S. Pat. No. 5,157,227
    • [32] U.S. Pat. No. 5,730,165
    • [33] U.S. Pat. No. 6,288,707
    • [34] U.S. Pat. No. 6,466,036
    • [35] U.S. Pat. No. 6,535,200
    • [36] U.S. Pat. No. 6,452,514
    • [37] U.S. 20030132922
    • [38] www.qprox.com/downloads/datasheets/qt110103.pdf
    • [39] U.S. Pat. No. 5,457,289
    • [40] www.qprox.com/downloads/datasheets/qt310103.pdf

Claims (19)

1. A touch sensitive position sensor comprising:
a substrate defining a touch sensitive platform;
first and second resistive bus-bars arranged spaced apart on the substrate; and
an anisotropic conductive area arranged between the bus-bars such that currents induced in the anisotropic conductive area flow preferentially towards the bus-bars.
2. A touch sensitive position sensor according to claim 1, wherein the bus-bars each have a resistance of between 1 kΩ and 50 kΩ.
3. A touch sensitive position sensor according to claim 1, wherein the bus-bars have substantially the same resistance.
4. A touch sensitive position sensor according to claim 1, wherein the anisotropic conductive area provides a resistance between the bus-bars of between 1 kΩ and 50 kΩ.
5. A touch sensitive position sensor according to claim 1, wherein the resistance of each of the bus-bars is less than the resistance between them provided by the anisotropic conductive area.
6. A touch sensitive position sensor according to claim 1, wherein the anisotropic conductive area comprises a film of molecular substance having anisotropic conduction supported on a substrate.
7. A touch sensitive position sensor according to claim 1, wherein the anisotropic conductive area comprises a plurality of resistive stripes connecting in parallel between the bus-bars.
8. A touch sensitive position sensor according to claim 7, wherein the resistive stripes are formed from sections of resistive wire.
9. A touch sensitive position sensor according to claim 7, wherein the resistive stripes are formed from a resistive material deposited on a substrate.
10. A touch sensitive position sensor according to claim 7, wherein the resistive stripes have widths that are greater than gaps formed between adjacent ones of the resistive stripes.
11. A touch sensitive position sensor according to claim 1, further comprising a conductive overlay separated from the anisotropic conductive area such that the conductive overlay and the anisotropic conductive area may be brought into contact by externally applied pressure.
12. A touch sensitive position sensor according to claim 1, wherein the first resistive bus-bar extends between a first and a second electrode and the first resistive bus-bar extends between a third and a fourth electrode, the position sensor further comprising first, second, third and fourth drive channels associated with respective ones of the first, second, third and fourth electrodes, each drive channel being operable to generate an output signal dependent on the resistance between its electrode and the position of the object.
13. A touch sensitive position sensor according to claim 12, further comprising a processor operable to generate an estimate for the position of the object by comparing the output signals from the drive channels.
14. A touch sensitive position sensor according to claim 13, wherein the processor is configured to estimate the position of the object in a first direction running between the bus-bars from a ratiometric analysis of the sum of the signals associated with the first and second electrodes and the sum of the signals associated with the third and fourth electrodes.
15. A touch sensitive position sensor according to claim 13, wherein the processor is configured to estimate the position of the object in a second direction running along the bus-bars from a ratiometric analysis of the sum of the signals associated with the first and third electrodes and the sum of the signals associated with the second and fourth electrodes.
16. A touch sensitive position sensor according to claim 13, wherein the processor is further operable to apply a correction to the estimated position according to a pre-determined distortion associated with the platform.
17. A touch sensitive position sensor according to claim 16, wherein the pre-determined distortion is a one-dimensional pin-cushion distortion.
18. A control panel incorporating a touch sensitive position sensor comprising:
a substrate defining a touch sensitive platform;
first and second resistive bus-bars arranged spaced apart on the substrate; and
an anisotropic conductive area arranged between the bus-bars such that currents induced in the anisotropic conductive area flow preferentially towards the bus-bars.
19. An apparatus having a control panel incorporating a touch sensitive position sensor comprising:
a substrate defining a touch sensitive platform;
first and second resistive bus-bars arranged spaced apart on the substrate; and
an anisotropic conductive area arranged between the bus-bars such that currents induced in the anisotropic conductive area flow preferentially towards the bus-bars.
US10/916,759 2003-08-21 2004-08-12 Anisotropic touch screen element Abandoned US20050041018A1 (en)

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US12/915,730 US8049738B2 (en) 2003-08-21 2010-10-29 Anisotropic, resistance-based determination of a position of an object with respect to a touch screen element
US13/286,153 US8847900B2 (en) 2003-08-21 2011-10-31 Determining a position of an object with respect to a touch screen element

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US12/915,730 Active US8049738B2 (en) 2003-08-21 2010-10-29 Anisotropic, resistance-based determination of a position of an object with respect to a touch screen element
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Cited By (86)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040019810A1 (en) * 2002-07-26 2004-01-29 Microsoft Corporation Capacitive sensing employing a repeatable offset charge
US20050035956A1 (en) * 2001-03-30 2005-02-17 Microsoft Corporation Capacitance touch slider
US20050078085A1 (en) * 2001-09-07 2005-04-14 Microsoft Corporation Data input device power management including beacon state
US6977646B1 (en) * 2001-11-30 2005-12-20 3M Innovative Properties Co. Touch screen calibration system and method
US20060207806A1 (en) * 2003-08-21 2006-09-21 Harald Philipp Anisotropic Touch Screen Element
US20060284856A1 (en) * 2005-06-10 2006-12-21 Soss David A Sensor signal conditioning in a force-based touch device
US20070257894A1 (en) * 2006-05-05 2007-11-08 Harald Philipp Touch Screen Element
EP1865407A2 (en) 2006-06-07 2007-12-12 Nokia Corporation Sensors for touch pad pointing device
US20070291011A1 (en) * 2006-06-20 2007-12-20 Chin-Fu Chang Control device and method with compensation of coordinate calculating for a capacitive touch panel
US20070291012A1 (en) * 2006-06-20 2007-12-20 Chin-Fu Chang Scanning control device for a capacitive touch panel
US20080030482A1 (en) * 2006-07-31 2008-02-07 Elwell James K Force-based input device having an elevated contacting surface
US20080165159A1 (en) * 2006-12-14 2008-07-10 Soss David A Force-based input device having a modular sensing component
US20080167832A1 (en) * 2005-06-10 2008-07-10 Qsi Corporation Method for determining when a force sensor signal baseline in a force-based input device can be updated
US20080170043A1 (en) * 2005-06-10 2008-07-17 Soss David A Force-based input device
US20080211782A1 (en) * 2003-01-17 2008-09-04 3M Innovative Properties Company Touch simulation system and method
US20080289887A1 (en) * 2007-05-22 2008-11-27 Qsi Corporation System and method for reducing vibrational effects on a force-based touch panel
US20080300036A1 (en) * 2005-01-22 2008-12-04 Herbert Wessling Gambling Machine
US20090020343A1 (en) * 2007-07-17 2009-01-22 Apple Inc. Resistive force sensor with capacitive discrimination
WO2009010308A1 (en) * 2007-07-19 2009-01-22 Volkswagen Ag Method for determining the position of an actuation element, in particular a finger of a user in a motor vehicle and position determination device
US20090066674A1 (en) * 2007-09-06 2009-03-12 Andriy Maharyta Calibration of single-layer touch-sensor device
US20090174675A1 (en) * 2008-01-09 2009-07-09 Dave Gillespie Locating multiple objects on a capacitive touch pad
US20090218310A1 (en) * 2008-02-28 2009-09-03 Lijun Zu Methods of patterning a conductor on a substrate
US20090219258A1 (en) * 2008-08-01 2009-09-03 3M Innovative Properties Company Touch screen sensor with low visibility conductors
US20090273571A1 (en) * 2008-05-01 2009-11-05 Alan Bowens Gesture Recognition
WO2009108765A3 (en) * 2008-02-28 2009-11-19 3M Innovative Properties Company Touch screen sensor having varying sheet resistance
DE102009019910A1 (en) 2008-05-01 2009-12-03 Atmel Corporation, San Jose Touch sensor device e.g. capacitive touch sensor device, for e.g. personal computer, has gesture unit analyzing time series data to distinguish gesture inputs, where unit is coded with gesture recognition code having linked state modules
US20100026659A1 (en) * 2008-07-30 2010-02-04 Flextronics Ap, Llc Glass substrate for capacitive touch panel and manufacturing method thereof
US20100033449A1 (en) * 2008-08-05 2010-02-11 Yen-Chen Chiu Touch screen and method for positioning coordinate
US20100045620A1 (en) * 2008-07-23 2010-02-25 Ding Hua Long Integration design for capacitive touch panels and liquid crystal displays
US20100139955A1 (en) * 2008-12-05 2010-06-10 Ding Hua Long Capacitive touch panel having dual resistive layer
US20100156810A1 (en) * 2008-12-22 2010-06-24 Fabrice Barbier Diamond pattern on a single layer
US20100156811A1 (en) * 2008-12-22 2010-06-24 Ding Hua Long New pattern design for a capacitive touch screen
US20100156846A1 (en) * 2008-12-23 2010-06-24 Flextronics Ap, Llc Single substrate capacitive touch panel
US20100214225A1 (en) * 2009-02-26 2010-08-26 Research In Motion Limited Method for and apparatus for display scrolling
US20100220063A1 (en) * 2009-02-27 2010-09-02 Panasonic Corporation System and methods for calibratable translation of position
US20100259505A1 (en) * 2006-06-20 2010-10-14 Egalax_Empia Technology Inc. System and Method for Scanning Control of a Capacitive Touch Panel
US20100327881A1 (en) * 2009-06-24 2010-12-30 Chin-Fu Chang Control unit, sensing device for a capacitive touch panel and method therefor
US20110001717A1 (en) * 2009-07-06 2011-01-06 Charles Hayes Narrow Border for Capacitive Touch Panels
US20110043481A1 (en) * 1998-10-09 2011-02-24 Frederick Johannes Bruwer User interface with proximity sensing
US7903090B2 (en) 2005-06-10 2011-03-08 Qsi Corporation Force-based input device
US20110057898A1 (en) * 2009-09-08 2011-03-10 Au Optronics Corp. Touch-sensing structure for touch panel and touch-sensing method thereof
US20110074733A1 (en) * 2008-05-19 2011-03-31 Maekinen Ville Interface apparatus for touch input and tactile output communication
US20110084927A1 (en) * 2009-10-09 2011-04-14 Egalax_Empia Technology Inc. Method and device for determining a touch or touches
US20110084930A1 (en) * 2009-10-09 2011-04-14 Egalax_Empia Technology Inc. Method and device for dual-differential sensing
US20110087455A1 (en) * 2009-10-09 2011-04-14 Egalax_Empia Technology Inc. Method and device for analyzing positions
US20110109588A1 (en) * 2009-11-12 2011-05-12 Senseg Ltd. Tactile stimulation apparatus having a composite section comprising a semiconducting material
EP2275911A3 (en) * 2009-07-10 2011-06-08 Chimei InnoLux Corporation Touch panel and multi-touch detecting method thereof
US20110157067A1 (en) * 2009-12-31 2011-06-30 Motorola, Inc. Duty cycle modulation of periodic time-synchronous receivers for noise reduction
US20110156800A1 (en) * 2008-09-19 2011-06-30 Atlab Inc. Sensor, sensing method thereof, and filter therefor
US20110216035A1 (en) * 2010-03-03 2011-09-08 Chimei Innolux Corporation Surface capacitive touch panel, driving method thereof and electronic apparatus using the same
US8127046B2 (en) 2006-12-04 2012-02-28 Deka Products Limited Partnership Medical device including a capacitive slider assembly that provides output signals wirelessly to one or more remote medical systems components
CN102478988A (en) * 2010-11-26 2012-05-30 奇美电子股份有限公司 Method for detecting touch point on touch screen
US20120154334A1 (en) * 2006-11-29 2012-06-21 Tsutomu Furuhashi Liquid Crystal Display Device With Touch Screen
USRE43606E1 (en) 2004-06-25 2012-08-28 Azoteq (Pty) Ltd Apparatus and method for a proximity and touch dependent user interface
US20120244348A1 (en) * 2009-09-28 2012-09-27 Lg Chem, Ltd. Touch panel
WO2013009778A1 (en) * 2011-07-14 2013-01-17 Apple Inc. Combined force and proximity sensing
US8384691B2 (en) 2008-02-28 2013-02-26 3M Innovative Properties Company Touch screen sensor
CN102999193A (en) * 2011-09-13 2013-03-27 天津富纳源创科技有限公司 Touch screen touch point detection method
US20130135249A1 (en) * 2011-11-25 2013-05-30 Shih Hua Technology Ltd. Capacitive touch panel, driving method for preventing leakage current
US8508680B2 (en) 2008-02-28 2013-08-13 3M Innovative Properties Company Touch screen sensor with low visibility conductors
US8525955B2 (en) 2012-01-31 2013-09-03 Multek Display (Hong Kong) Limited Heater for liquid crystal display
US8531433B2 (en) 2010-07-21 2013-09-10 Synaptics Incorporated Producing capacitive images comprising non-connection values
US20140333583A1 (en) * 2012-01-31 2014-11-13 Fujitsu Component Limited Position detection method in touch panel and touch panel
US20150002440A1 (en) * 2013-06-26 2015-01-01 Tianjin Funayuanchuang Technology Co., Ltd. Method and apparatus for determining touch point coordinates on a touch panel with anisotropic films
US8941475B2 (en) 2007-09-18 2015-01-27 Senseg Oy Method and apparatus for sensory stimulation
US20150145795A1 (en) * 2013-11-28 2015-05-28 Tianjim Funayuanchuang Technology Co., Ltd. Method for controlling touch panel
US20160018946A1 (en) * 2010-06-07 2016-01-21 Apple Inc. Touch sensing error compensation
WO2016014132A1 (en) * 2014-07-23 2016-01-28 Preemadonna Inc. Apparatus for applying coating to nails
US9285929B2 (en) 2010-03-30 2016-03-15 New Vision Display (Shenzhen) Co., Limited Touchscreen system with simplified mechanical touchscreen design using capacitance and acoustic sensing technologies, and method therefor
US9348477B2 (en) 2005-11-15 2016-05-24 Synaptics Incorporated Methods and systems for detecting a position-based attribute of an object using digital codes
US9386542B2 (en) 2013-09-19 2016-07-05 Google Technology Holdings, LLC Method and apparatus for estimating transmit power of a wireless device
US9401750B2 (en) 2010-05-05 2016-07-26 Google Technology Holdings LLC Method and precoder information feedback in multi-antenna wireless communication systems
US20160239699A1 (en) * 2015-02-16 2016-08-18 Xintec Inc. Chip scale sensing chip package and a manufacturing method thereof
US9444452B2 (en) 2012-02-24 2016-09-13 Parade Technologies, Ltd. Frequency hopping algorithm for capacitance sensing devices
US9478847B2 (en) 2014-06-02 2016-10-25 Google Technology Holdings LLC Antenna system and method of assembly for a wearable electronic device
US9491007B2 (en) 2014-04-28 2016-11-08 Google Technology Holdings LLC Apparatus and method for antenna matching
US9549290B2 (en) 2013-12-19 2017-01-17 Google Technology Holdings LLC Method and apparatus for determining direction information for a wireless device
US9591508B2 (en) 2012-12-20 2017-03-07 Google Technology Holdings LLC Methods and apparatus for transmitting data between different peer-to-peer communication groups
US9687059B2 (en) * 2013-08-23 2017-06-27 Preemadonna Inc. Nail decorating apparatus
US9813262B2 (en) 2012-12-03 2017-11-07 Google Technology Holdings LLC Method and apparatus for selectively transmitting data using spatial diversity
US9841840B2 (en) 2011-02-07 2017-12-12 Parade Technologies, Ltd. Noise filtering devices, systems and methods for capacitance sensing devices
US9886157B2 (en) 2014-12-02 2018-02-06 Fujitsu Component Limited Touch panel device and method of correcting coordinates on touch panel
US9921668B1 (en) * 2013-01-25 2018-03-20 Qualcomm Incorporated Touch panel controller integrated with host processor for dynamic baseline image update
US9927924B2 (en) 2008-09-26 2018-03-27 Apple Inc. Differential sensing for a touch panel
US9979531B2 (en) 2013-01-03 2018-05-22 Google Technology Holdings LLC Method and apparatus for tuning a communication device for multi band operation
US10229697B2 (en) 2013-03-12 2019-03-12 Google Technology Holdings LLC Apparatus and method for beamforming to obtain voice and noise signals

Families Citing this family (76)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9722766D0 (en) 1997-10-28 1997-12-24 British Telecomm Portable computers
US7663607B2 (en) 2004-05-06 2010-02-16 Apple Inc. Multipoint touchscreen
WO2006068782A2 (en) * 2004-12-22 2006-06-29 3M Innovative Properties Company Touch sensors incorporating capacitively coupled electrodes
US7279647B2 (en) 2005-06-17 2007-10-09 Harald Philipp Control panel
US8144125B2 (en) 2006-03-30 2012-03-27 Cypress Semiconductor Corporation Apparatus and method for reducing average scan rate to detect a conductive object on a sensing device
US10203814B2 (en) 2006-04-20 2019-02-12 Nokia Technologies Oy Sensor arrangement comprising a conductive layer
US8279180B2 (en) * 2006-05-02 2012-10-02 Apple Inc. Multipoint touch surface controller
US8619054B2 (en) 2006-05-31 2013-12-31 Atmel Corporation Two dimensional position sensor
US8063886B2 (en) * 2006-07-18 2011-11-22 Iee International Electronics & Engineering S.A. Data input device
US20080088595A1 (en) * 2006-10-12 2008-04-17 Hua Liu Interconnected two-substrate layer touchpad capacitive sensing device
US8072429B2 (en) 2006-12-22 2011-12-06 Cypress Semiconductor Corporation Multi-axial touch-sensor device with multi-touch resolution
US7920129B2 (en) 2007-01-03 2011-04-05 Apple Inc. Double-sided touch-sensitive panel with shield and drive combined layer
US7986313B2 (en) * 2007-01-03 2011-07-26 Apple Inc. Analog boundary scanning based on stray capacitance
US8144126B2 (en) 2007-05-07 2012-03-27 Cypress Semiconductor Corporation Reducing sleep current in a capacitance sensing system
JP5151257B2 (en) * 2007-06-04 2013-02-27 トヨタ自動車株式会社 Electrical equipment and a method of manufacturing the same
US8063330B2 (en) * 2007-06-22 2011-11-22 Nokia Corporation Uniform threshold for capacitive sensing
GB2451267A (en) * 2007-07-26 2009-01-28 Harald Philipp Capacitive position sensor
US7808490B2 (en) * 2007-08-29 2010-10-05 Egalax—Empia Technology Inc. Device and method for determining touch position on sensing area of capacitive touch panel
US8400265B2 (en) * 2007-09-17 2013-03-19 Magna International Inc. Touchless keyless entry keypad integrated with electroluminescence backlight
TWI361997B (en) * 2007-10-02 2012-04-11
US8059103B2 (en) * 2007-11-21 2011-11-15 3M Innovative Properties Company System and method for determining touch positions based on position-dependent electrical charges
JP5123952B2 (en) * 2007-12-14 2013-01-23 京セラ株式会社 Touch panel and a touch panel-type display device
US20090153494A1 (en) * 2007-12-18 2009-06-18 Kevin Scott Laundroche Touch display for an appliance
TWI374379B (en) 2007-12-24 2012-10-11 Wintek Corp Transparent capacitive touch panel and manufacturing method thereof
US9740341B1 (en) 2009-02-26 2017-08-22 Amazon Technologies, Inc. Capacitive sensing with interpolating force-sensitive resistor array
US10180746B1 (en) 2009-02-26 2019-01-15 Amazon Technologies, Inc. Hardware enabled interpolating sensor and display
JP5154316B2 (en) 2008-06-30 2013-02-27 株式会社ジャパンディスプレイイースト Touch panel
JP5370723B2 (en) * 2008-09-29 2013-12-18 株式会社ジャパンディスプレイ Capacitive input device, a display device and an electronic apparatus with an input function
KR101497419B1 (en) * 2008-11-10 2015-03-02 위순임 A touch screen device with a two-dimensional conductive sensing mans
KR101497416B1 (en) * 2008-11-15 2015-03-02 위순임 A touch screen device with a two-dimensional conductive sensing mans
US8183875B2 (en) * 2008-11-26 2012-05-22 3M Innovative Properties Company System and method for determining touch positions based on passively-induced position-dependent electrical charges
JP2010186460A (en) * 2009-01-19 2010-08-26 Panasonic Corp Touch panel
US8508492B2 (en) * 2009-01-19 2013-08-13 Panasonic Corporation Touch panel and method of detecting press operation position thereon
KR101666489B1 (en) * 2009-03-26 2016-10-14 (주) 엔피홀딩스 Touchscreen device having conductive sensing-net of two dimensions
US8174510B2 (en) 2009-03-29 2012-05-08 Cypress Semiconductor Corporation Capacitive touch screen
TWI398807B (en) * 2009-04-07 2013-06-11 Ite Tech Inc Posistion apparatus for touch device and posistion method thereof
TWI466004B (en) 2009-04-17 2014-12-21 Egalax Empia Technology Inc Method and device for resistive multi-point touch
US8547345B2 (en) * 2009-05-04 2013-10-01 Microsoft Corporation Touch sensitive LCD panel
CN101943975B (en) * 2009-07-09 2015-12-16 敦泰科技有限公司 Ultrathin mutual capacitance touch screen and combined ultrathin touch screen
TWI395998B (en) * 2009-07-15 2013-05-11 Innolux Corp Conductive plate and touch plate applied by the same
US9753597B2 (en) 2009-07-24 2017-09-05 Cypress Semiconductor Corporation Mutual capacitance sensing array
US20110018829A1 (en) * 2009-07-24 2011-01-27 Cypress Semiconductor Corporation Mutual capacitance sensing array
US9244562B1 (en) * 2009-07-31 2016-01-26 Amazon Technologies, Inc. Gestures and touches on force-sensitive input devices
US9785272B1 (en) 2009-07-31 2017-10-10 Amazon Technologies, Inc. Touch distinction
US8791907B2 (en) 2009-08-19 2014-07-29 U-Pixel Technologies Inc. Touch sensing apparatus and method using different modulated driving signals
CN101995988B (en) 2009-08-19 2012-08-15 奇美电子股份有限公司 Touch screen
TWI512553B (en) * 2009-09-21 2015-12-11 Silicon Integrated Sys Corp Touch sensing apparatus and method
US9557837B2 (en) * 2010-06-15 2017-01-31 Pixart Imaging Inc. Touch input apparatus and operation method thereof
US20110102331A1 (en) * 2009-10-29 2011-05-05 Qrg Limited Redundant touchscreen electrodes
US8810524B1 (en) 2009-11-20 2014-08-19 Amazon Technologies, Inc. Two-sided touch sensor
TWI413928B (en) * 2010-03-17 2013-11-01 Innolux Corp Touch panel and differential detection method for same
KR101109382B1 (en) * 2010-04-12 2012-01-30 삼성전기주식회사 touch panel
US8941395B2 (en) * 2010-04-27 2015-01-27 3M Innovative Properties Company Integrated passive circuit elements for sensing devices
US20110273372A1 (en) * 2010-05-09 2011-11-10 Elsid Aliaj Mobile device with unique features
JP5427126B2 (en) * 2010-07-01 2014-02-26 アルパイン株式会社 Calibration method of an electronic device and a touch panel
US20120038577A1 (en) * 2010-08-16 2012-02-16 Floatingtouch, Llc Floating plane touch input device and method
DE102010044820B4 (en) * 2010-09-09 2015-01-22 Ident Technology Ag Sensor device and method for detecting proximity and touch
TW201218028A (en) 2010-10-26 2012-05-01 Novatek Microelectronics Corp Coordinates algorithm of touch panel
US20120105325A1 (en) * 2010-10-27 2012-05-03 Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. Capacitive finger navigation input device
CN103250350A (en) 2010-11-30 2013-08-14 瑟克公司 Linear projected single-layer capacitance sensor
TWI459267B (en) * 2011-04-26 2014-11-01 Shih Hua Technology Ltd Method for detecting touch spot of touch panel
TWI447635B (en) * 2011-04-29 2014-08-01 Shih Hua Technology Ltd Method for detecting touch trace based on resistive touch panel
TWI453649B (en) * 2011-05-02 2014-09-21 Shih Hua Technology Ltd Display device with touch panel
TWI454978B (en) * 2011-05-02 2014-10-01 Shih Hua Technology Ltd Touching based input device
TWI461997B (en) * 2011-05-25 2014-11-21 Innolux Corp Method and apparatus for driving a touch panel with an anisotropic material and touch panel module
TWI585658B (en) * 2011-06-03 2017-06-01 Shih Hua Tech Ltd Method for detecting touch spot of touch panel
US20130100041A1 (en) * 2011-10-21 2013-04-25 Touch Turns Llc System for a single-layer sensor having reduced number of interconnect pads for the interconnect periphery of the sensor panel
TW201319921A (en) * 2011-11-07 2013-05-16 Benq Corp Method for screen control and method for screen display on a touch screen
FR2985049B1 (en) 2011-12-22 2014-01-31 Nanotec Solution A capacitive measurement electrodes has SWITCHED for tactile interfaces and contactless
TWI456470B (en) * 2012-03-07 2014-10-11 Himax Tech Ltd Touch cell applied to capacitive touch panel and associated capacitive touch panel
WO2014015032A2 (en) 2012-07-19 2014-01-23 Cypress Semiconductor Corporation Touchscreen data processing
US8988387B2 (en) * 2012-08-02 2015-03-24 Google Technology Holdings LLC Touch sensor panel with in-plane backup bypass connections
US9007343B1 (en) * 2013-10-01 2015-04-14 Synaptics Incorporated Display guarding techniques
US9857925B2 (en) * 2014-09-30 2018-01-02 Synaptics Incorporated Combining sensor electrodes in a matrix sensor
CN105607791A (en) 2014-11-13 2016-05-25 财团法人工业技术研究院 Conductive line structure and sensing element
CN105630264B (en) * 2016-02-22 2019-01-18 京东方科技集团股份有限公司 Touch base plate and production method, driving device and driving method, display device

Citations (46)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2338949A (en) * 1939-10-16 1944-01-11 Kupfmuller Karl Telautograph
US2925467A (en) * 1958-10-31 1960-02-16 Bell Telephone Labor Inc Electrographic transmitter
US3699439A (en) * 1969-03-13 1972-10-17 Automatic Radio Mfg Co Electrical probe-position responsive apparatus and method
US3921166A (en) * 1972-09-15 1975-11-18 Raytheon Co Capacitance matrix keyboard
US4198539A (en) * 1977-01-19 1980-04-15 Peptek, Inc. System for producing electric field with predetermined characteristics and edge terminations for resistance planes therefor
US4293734A (en) * 1979-02-23 1981-10-06 Peptek, Incorporated Touch panel system and method
US4371746A (en) * 1978-01-05 1983-02-01 Peptek, Incorporated Edge terminations for impedance planes
US4649232A (en) * 1985-06-07 1987-03-10 Scriptel Corporation Electrographic apparatus
US4650926A (en) * 1984-10-26 1987-03-17 Scriptel Corporation Electrographic system and method
US4678869A (en) * 1985-10-25 1987-07-07 Scriptel Corporation Position responsive apparatus, system and method having electrographic application
US4680430A (en) * 1984-02-29 1987-07-14 Fujitsu Limited Coordinate detecting apparatus
US4686332A (en) * 1986-06-26 1987-08-11 International Business Machines Corporation Combined finger touch and stylus detection system for use on the viewing surface of a visual display device
US4733222A (en) * 1983-12-27 1988-03-22 Integrated Touch Arrays, Inc. Capacitance-variation-sensitive touch sensing array system
US4822957A (en) * 1984-12-24 1989-04-18 Elographics, Inc. Electrographic touch sensor having reduced bow of equipotential field lines therein
US4827084A (en) * 1987-11-19 1989-05-02 Ovonic Imaging Systems, Inc. Solid state image detector and signal generator
US5101081A (en) * 1991-03-25 1992-03-31 Wang Laboratories, Inc. Graphics surface assembly with calibrating memory device
US5149919A (en) * 1990-10-31 1992-09-22 International Business Machines Corporation Stylus sensing system
US5157227A (en) * 1991-01-17 1992-10-20 Summagraphics Corporation Digitizer tablet with regional error correction
US5181030A (en) * 1989-12-28 1993-01-19 Gunze Limited Input system including resistance film touch panel and pushed position detecting device
US5305017A (en) * 1989-08-16 1994-04-19 Gerpheide George E Methods and apparatus for data input
US5381160A (en) * 1991-09-27 1995-01-10 Calcomp Inc. See-through digitizer with clear conductive grid
US5438168A (en) * 1992-03-18 1995-08-01 Gunze Limited Touch panel
US5455574A (en) * 1992-02-27 1995-10-03 Gunze Limited Touch panel device including resistance material and position detecting unit
US5457289A (en) * 1994-03-16 1995-10-10 Microtouch Systems, Inc. Frontally shielded capacitive touch sensor system
US5463388A (en) * 1993-01-29 1995-10-31 At&T Ipm Corp. Computer mouse or keyboard input device utilizing capacitive sensors
US5682032A (en) * 1996-02-22 1997-10-28 Philipp; Harald Capacitively coupled identity verification and escort memory apparatus
US5730165A (en) * 1995-12-26 1998-03-24 Philipp; Harald Time domain capacitive field detector
US5790106A (en) * 1994-11-15 1998-08-04 Alps Electric Co., Ltd. Coordinate input apparatus with pen and finger input detection
US5818430A (en) * 1997-01-24 1998-10-06 C.A.M. Graphics Co., Inc. Touch screen
US5844506A (en) * 1994-04-05 1998-12-01 Binstead; Ronald Peter Multiple input proximity detector and touchpad system
US5898426A (en) * 1996-04-16 1999-04-27 Samsung Display Devices Co., Ltd. Touch panel input device
US5914465A (en) * 1992-06-08 1999-06-22 Synaptics, Inc. Object position detector
US5940065A (en) * 1996-03-15 1999-08-17 Elo Touchsystems, Inc. Algorithmic compensation system and method therefor for a touch sensor panel
US5945639A (en) * 1994-02-04 1999-08-31 Hyundai Electronics America Cancellation of common-mode signals in digitizing tablet
US6016140A (en) * 1997-10-29 2000-01-18 Nortel Networks Corporation Automatic touch screen calibration
US6208332B1 (en) * 1997-09-17 2001-03-27 Nec Corporation Resistance film tablet system capable of rapidly detecting a position of contact and method of controlling the same
US6239790B1 (en) * 1996-08-05 2001-05-29 Interlink Electronics Force sensing semiconductive touchpad
US6288707B1 (en) * 1996-07-29 2001-09-11 Harald Philipp Capacitive position sensor
US6429846B2 (en) * 1998-06-23 2002-08-06 Immersion Corporation Haptic feedback for touchpads and other touch controls
US6452514B1 (en) * 1999-01-26 2002-09-17 Harald Philipp Capacitive sensor and array
US6466036B1 (en) * 1998-11-25 2002-10-15 Harald Philipp Charge transfer capacitance measurement circuit
US20020180578A1 (en) * 1999-05-20 2002-12-05 Eleksen Limited Detector constructed from fabric
US6504530B1 (en) * 1999-09-07 2003-01-07 Elo Touchsystems, Inc. Touch confirming touchscreen utilizing plural touch sensors
US6535200B2 (en) * 1999-01-25 2003-03-18 Harald Philipp Capacitive position sensor
US20030132922A1 (en) * 2002-01-17 2003-07-17 Harald Philipp Touch screen detection apparatus
US7180508B2 (en) * 2002-09-17 2007-02-20 Tyco Electronics Corporation Dynamic corrections for a non-linear touchscreen

Family Cites Families (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE203719C (en) 1907-11-02 1908-10-20
US645251A (en) * 1899-09-05 1900-03-13 Charles F Dittmar Child's carriage.
US4622437A (en) * 1984-11-29 1986-11-11 Interaction Systems, Inc. Method and apparatus for improved electronic touch mapping
JPH0191350A (en) 1987-09-30 1989-04-11 Showa Alum Corp Surface treatment of aluminum alloy cylinder for tape recorder
JPH0237413A (en) * 1988-07-27 1990-02-07 Oki Electric Ind Co Ltd Coordinate input device
US4963702A (en) * 1989-02-09 1990-10-16 Interlink Electronics, Inc. Digitizer pad featuring spacial definition of a pressure contact area
BE1007462A3 (en) * 1993-08-26 1995-07-04 Philips Electronics Nv Data processing device with touch sensor and power.
JP3825487B2 (en) * 1995-03-03 2006-09-27 日本写真印刷株式会社 Transparent touch panel
US5815141A (en) * 1996-04-12 1998-09-29 Elo Touch Systems, Inc. Resistive touchscreen having multiple selectable regions for pressure discrimination
JPH09293428A (en) * 1996-04-26 1997-11-11 Fujikura Ltd Membrane switch
JPH09305291A (en) * 1996-05-17 1997-11-28 Fujitsu Takamizawa Component Kk Touch input panel
JPH1091350A (en) * 1996-09-10 1998-04-10 Tokyo Cosmos Electric Co Ltd Touch panel
US6057903A (en) * 1998-08-18 2000-05-02 International Business Machines Corporation Liquid crystal display device employing a guard plane between a layer for measuring touch position and common electrode layer
KR100473592B1 (en) * 1999-07-19 2005-03-07 엘지.필립스 엘시디 주식회사 A digitizer
US20040207606A1 (en) * 1999-11-08 2004-10-21 Atwood Stephen P. Sensing the size of a touch point in a touch-sensitive panel employing resistive membranes
JP4550251B2 (en) * 2000-09-29 2010-09-22 日本写真印刷株式会社 Narrow frame touch panel
US6593916B1 (en) * 2000-11-03 2003-07-15 James L. Aroyan Touchscreen having multiple parallel connections to each electrode in a series resistor chain on the periphery of the touch area
JP3764865B2 (en) * 2000-11-06 2006-04-12 日本写真印刷株式会社 Wide area can be input touch panel
GB2371910A (en) * 2001-01-31 2002-08-07 Seiko Epson Corp Display devices
JP3815239B2 (en) * 2001-03-13 2006-08-30 日本電気株式会社 Mounting structure and a printed wiring board of the semiconductor element
US6933931B2 (en) * 2002-08-23 2005-08-23 Ceronix, Inc. Method and apparatus of position location
JP4239197B2 (en) 2003-06-25 2009-03-18 和光工業株式会社 Slide frame driving device for elevating stand apparatus for a vehicle
GB0319714D0 (en) 2003-08-21 2003-09-24 Philipp Harald Anisotropic touch screen element
US7663607B2 (en) * 2004-05-06 2010-02-16 Apple Inc. Multipoint touchscreen
EP1746488A2 (en) 2005-07-21 2007-01-24 TPO Displays Corp. Electromagnetic digitizer sensor array structure
US8031174B2 (en) 2007-01-03 2011-10-04 Apple Inc. Multi-touch surface stackup arrangement
US7920129B2 (en) * 2007-01-03 2011-04-05 Apple Inc. Double-sided touch-sensitive panel with shield and drive combined layer
US8049732B2 (en) 2007-01-03 2011-11-01 Apple Inc. Front-end signal compensation
US8040326B2 (en) 2007-06-13 2011-10-18 Apple Inc. Integrated in-plane switching display and touch sensor
KR101717032B1 (en) 2008-02-28 2017-03-15 쓰리엠 이노베이티브 프로퍼티즈 컴파니 Touch screen sensors
JP4720857B2 (en) 2008-06-18 2011-07-13 ソニー株式会社 Capacitive input device and display device with an input function
US8031094B2 (en) 2009-09-11 2011-10-04 Apple Inc. Touch controller with improved analog front end
US9178970B2 (en) 2011-03-21 2015-11-03 Apple Inc. Electronic devices with convex displays
US9866660B2 (en) 2011-03-21 2018-01-09 Apple Inc. Electronic devices with concave displays
EP2673944B1 (en) 2011-03-21 2017-11-01 Apple Inc. Electronic devices with flexible displays
US8816977B2 (en) 2011-03-21 2014-08-26 Apple Inc. Electronic devices with flexible displays
US8934228B2 (en) 2011-03-21 2015-01-13 Apple Inc. Display-based speaker structures for electronic devices

Patent Citations (49)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2338949A (en) * 1939-10-16 1944-01-11 Kupfmuller Karl Telautograph
US2925467A (en) * 1958-10-31 1960-02-16 Bell Telephone Labor Inc Electrographic transmitter
US3699439A (en) * 1969-03-13 1972-10-17 Automatic Radio Mfg Co Electrical probe-position responsive apparatus and method
US3921166A (en) * 1972-09-15 1975-11-18 Raytheon Co Capacitance matrix keyboard
US4198539A (en) * 1977-01-19 1980-04-15 Peptek, Inc. System for producing electric field with predetermined characteristics and edge terminations for resistance planes therefor
US4371746A (en) * 1978-01-05 1983-02-01 Peptek, Incorporated Edge terminations for impedance planes
US4293734A (en) * 1979-02-23 1981-10-06 Peptek, Incorporated Touch panel system and method
US4733222A (en) * 1983-12-27 1988-03-22 Integrated Touch Arrays, Inc. Capacitance-variation-sensitive touch sensing array system
US4680430A (en) * 1984-02-29 1987-07-14 Fujitsu Limited Coordinate detecting apparatus
US4650926A (en) * 1984-10-26 1987-03-17 Scriptel Corporation Electrographic system and method
US4822957A (en) * 1984-12-24 1989-04-18 Elographics, Inc. Electrographic touch sensor having reduced bow of equipotential field lines therein
US4822957B1 (en) * 1984-12-24 1996-11-19 Elographics Inc Electrographic touch sensor having reduced bow of equipotential field lines therein
US4649232A (en) * 1985-06-07 1987-03-10 Scriptel Corporation Electrographic apparatus
US4678869A (en) * 1985-10-25 1987-07-07 Scriptel Corporation Position responsive apparatus, system and method having electrographic application
US4686332A (en) * 1986-06-26 1987-08-11 International Business Machines Corporation Combined finger touch and stylus detection system for use on the viewing surface of a visual display device
US4827084A (en) * 1987-11-19 1989-05-02 Ovonic Imaging Systems, Inc. Solid state image detector and signal generator
US5305017A (en) * 1989-08-16 1994-04-19 Gerpheide George E Methods and apparatus for data input
US5181030A (en) * 1989-12-28 1993-01-19 Gunze Limited Input system including resistance film touch panel and pushed position detecting device
US5149919A (en) * 1990-10-31 1992-09-22 International Business Machines Corporation Stylus sensing system
US5157227A (en) * 1991-01-17 1992-10-20 Summagraphics Corporation Digitizer tablet with regional error correction
US5101081A (en) * 1991-03-25 1992-03-31 Wang Laboratories, Inc. Graphics surface assembly with calibrating memory device
US5381160A (en) * 1991-09-27 1995-01-10 Calcomp Inc. See-through digitizer with clear conductive grid
US5455574A (en) * 1992-02-27 1995-10-03 Gunze Limited Touch panel device including resistance material and position detecting unit
US5438168A (en) * 1992-03-18 1995-08-01 Gunze Limited Touch panel
US5914465A (en) * 1992-06-08 1999-06-22 Synaptics, Inc. Object position detector
US5463388A (en) * 1993-01-29 1995-10-31 At&T Ipm Corp. Computer mouse or keyboard input device utilizing capacitive sensors
US5945639A (en) * 1994-02-04 1999-08-31 Hyundai Electronics America Cancellation of common-mode signals in digitizing tablet
US5457289A (en) * 1994-03-16 1995-10-10 Microtouch Systems, Inc. Frontally shielded capacitive touch sensor system
US5844506A (en) * 1994-04-05 1998-12-01 Binstead; Ronald Peter Multiple input proximity detector and touchpad system
US6137427A (en) * 1994-04-05 2000-10-24 Binstead; Ronald Peter Multiple input proximity detector and touchpad system
US5790106A (en) * 1994-11-15 1998-08-04 Alps Electric Co., Ltd. Coordinate input apparatus with pen and finger input detection
US5730165A (en) * 1995-12-26 1998-03-24 Philipp; Harald Time domain capacitive field detector
US5682032A (en) * 1996-02-22 1997-10-28 Philipp; Harald Capacitively coupled identity verification and escort memory apparatus
US5940065A (en) * 1996-03-15 1999-08-17 Elo Touchsystems, Inc. Algorithmic compensation system and method therefor for a touch sensor panel
US6506983B1 (en) * 1996-03-15 2003-01-14 Elo Touchsystems, Inc. Algorithmic compensation system and method therefor for a touch sensor panel
US5898426A (en) * 1996-04-16 1999-04-27 Samsung Display Devices Co., Ltd. Touch panel input device
US6288707B1 (en) * 1996-07-29 2001-09-11 Harald Philipp Capacitive position sensor
US6239790B1 (en) * 1996-08-05 2001-05-29 Interlink Electronics Force sensing semiconductive touchpad
US5818430A (en) * 1997-01-24 1998-10-06 C.A.M. Graphics Co., Inc. Touch screen
US6208332B1 (en) * 1997-09-17 2001-03-27 Nec Corporation Resistance film tablet system capable of rapidly detecting a position of contact and method of controlling the same
US6016140A (en) * 1997-10-29 2000-01-18 Nortel Networks Corporation Automatic touch screen calibration
US6429846B2 (en) * 1998-06-23 2002-08-06 Immersion Corporation Haptic feedback for touchpads and other touch controls
US6466036B1 (en) * 1998-11-25 2002-10-15 Harald Philipp Charge transfer capacitance measurement circuit
US6535200B2 (en) * 1999-01-25 2003-03-18 Harald Philipp Capacitive position sensor
US6452514B1 (en) * 1999-01-26 2002-09-17 Harald Philipp Capacitive sensor and array
US20020180578A1 (en) * 1999-05-20 2002-12-05 Eleksen Limited Detector constructed from fabric
US6504530B1 (en) * 1999-09-07 2003-01-07 Elo Touchsystems, Inc. Touch confirming touchscreen utilizing plural touch sensors
US20030132922A1 (en) * 2002-01-17 2003-07-17 Harald Philipp Touch screen detection apparatus
US7180508B2 (en) * 2002-09-17 2007-02-20 Tyco Electronics Corporation Dynamic corrections for a non-linear touchscreen

Cited By (179)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9645692B2 (en) 1998-10-09 2017-05-09 Global Touch Solutions, Llc User interface with proximity sensing
US9226376B2 (en) 1998-10-09 2015-12-29 Global Touch Solutions, Llc User interface with proximity sensing
US9588628B2 (en) 1998-10-09 2017-03-07 Global Touch Solutions, Llc User interface with proximity sensing
US20110043481A1 (en) * 1998-10-09 2011-02-24 Frederick Johannes Bruwer User interface with proximity sensing
US8035623B2 (en) 1998-10-09 2011-10-11 Azoteq (Pty) Ltd. User interface with proximity sensing
US20050035956A1 (en) * 2001-03-30 2005-02-17 Microsoft Corporation Capacitance touch slider
US7812825B2 (en) 2001-03-30 2010-10-12 Microsoft Corporation Capacitance touch slider
US7158125B2 (en) 2001-03-30 2007-01-02 Microsoft Corporation Capacitance touch slider
US20050062732A1 (en) * 2001-03-30 2005-03-24 Microsoft Corporation Capacitance touch slider
US7050927B2 (en) 2001-03-30 2006-05-23 Microsoft Corporation Capacitance touch slider
US20070046651A1 (en) * 2001-03-30 2007-03-01 Microsoft Corporation Capacitance touch slider
US20050168438A1 (en) * 2001-09-07 2005-08-04 Microsoft Corporation Capacitive sensing and data input device power management
US20050078085A1 (en) * 2001-09-07 2005-04-14 Microsoft Corporation Data input device power management including beacon state
US6995747B2 (en) 2001-09-07 2006-02-07 Microsoft Corporation Capacitive sensing and data input device power management
US7639238B2 (en) 2001-11-30 2009-12-29 3M Innovative Properties Company Method for simulating a touch on a touch screen
US20060202969A1 (en) * 2001-11-30 2006-09-14 3M Innovative Properties Company Method for simulating a touch on a touch screen
US6977646B1 (en) * 2001-11-30 2005-12-20 3M Innovative Properties Co. Touch screen calibration system and method
US20050240785A1 (en) * 2002-07-26 2005-10-27 Microsoft Corporation Capacitive sensing employing a repeatable offset charge
US7124312B2 (en) 2002-07-26 2006-10-17 Microsoft Corporation Capacitive sensing employing a repeatable offset charge
US6954867B2 (en) 2002-07-26 2005-10-11 Microsoft Corporation Capacitive sensing employing a repeatable offset charge
US20040019810A1 (en) * 2002-07-26 2004-01-29 Microsoft Corporation Capacitive sensing employing a repeatable offset charge
US20080211782A1 (en) * 2003-01-17 2008-09-04 3M Innovative Properties Company Touch simulation system and method
US7825905B2 (en) 2003-08-21 2010-11-02 Atmel Corporation Anisotropic touch screen element
US8847900B2 (en) 2003-08-21 2014-09-30 Atmel Corporation Determining a position of an object with respect to a touch screen element
US20060207806A1 (en) * 2003-08-21 2006-09-21 Harald Philipp Anisotropic Touch Screen Element
US8049738B2 (en) 2003-08-21 2011-11-01 Atmel Corporation Anisotropic, resistance-based determination of a position of an object with respect to a touch screen element
US20110043482A1 (en) * 2003-08-21 2011-02-24 Atmel Corporation Anisotropic touch screen element
USRE43606E1 (en) 2004-06-25 2012-08-28 Azoteq (Pty) Ltd Apparatus and method for a proximity and touch dependent user interface
US20080300036A1 (en) * 2005-01-22 2008-12-04 Herbert Wessling Gambling Machine
US8070602B2 (en) * 2005-01-22 2011-12-06 Herbert Wessling Gambling machine
US7698084B2 (en) 2005-06-10 2010-04-13 Qsi Corporation Method for determining when a force sensor signal baseline in a force-based input device can be updated
US20080170043A1 (en) * 2005-06-10 2008-07-17 Soss David A Force-based input device
US20080167832A1 (en) * 2005-06-10 2008-07-10 Qsi Corporation Method for determining when a force sensor signal baseline in a force-based input device can be updated
US20060284856A1 (en) * 2005-06-10 2006-12-21 Soss David A Sensor signal conditioning in a force-based touch device
US7903090B2 (en) 2005-06-10 2011-03-08 Qsi Corporation Force-based input device
US9696863B2 (en) 2005-11-15 2017-07-04 Synaptics Incorporated Methods and systems for detecting a position-based attribute of an object using digital codes
US9348477B2 (en) 2005-11-15 2016-05-24 Synaptics Incorporated Methods and systems for detecting a position-based attribute of an object using digital codes
DE102007021029B4 (en) * 2006-05-05 2016-12-15 Atmel Corp. Loser pen two-dimensional capacitive transducer
US9430104B2 (en) 2006-05-05 2016-08-30 Atmel Corporation Touch screen element
US8648819B2 (en) 2006-05-05 2014-02-11 Atmel Corporation Touch screen element
US20070257894A1 (en) * 2006-05-05 2007-11-08 Harald Philipp Touch Screen Element
US20100271330A1 (en) * 2006-05-05 2010-10-28 Atmel Corporation Touch screen element
KR100932734B1 (en) * 2006-06-07 2009-12-21 노키아 코포레이션 Sensors
US20070285398A1 (en) * 2006-06-07 2007-12-13 Nokia Corporation Sensors
US7830365B2 (en) 2006-06-07 2010-11-09 Nokia Corporation Sensors
EP1865407A2 (en) 2006-06-07 2007-12-12 Nokia Corporation Sensors for touch pad pointing device
EP1865407A3 (en) * 2006-06-07 2009-05-13 Nokia Corporation Sensors for touch pad pointing device
US20100259505A1 (en) * 2006-06-20 2010-10-14 Egalax_Empia Technology Inc. System and Method for Scanning Control of a Capacitive Touch Panel
US20070291012A1 (en) * 2006-06-20 2007-12-20 Chin-Fu Chang Scanning control device for a capacitive touch panel
US20070291011A1 (en) * 2006-06-20 2007-12-20 Chin-Fu Chang Control device and method with compensation of coordinate calculating for a capacitive touch panel
US7839393B2 (en) * 2006-06-20 2010-11-23 Egalax—Empia Technology Inc. Control device and method with compensation of coordinate calculating for a capacitive touch panel
US9626044B2 (en) 2006-06-20 2017-04-18 Egalax_Empia Technology Inc. System and method for scanning control of a capacitive touch panel
US20080030482A1 (en) * 2006-07-31 2008-02-07 Elwell James K Force-based input device having an elevated contacting surface
US9983758B2 (en) 2006-11-29 2018-05-29 Japan Display Inc. Liquid crystal display device with touch screen
US10191606B2 (en) 2006-11-29 2019-01-29 Japan Display Inc. Liquid crystal display device with touch screen
US20120154334A1 (en) * 2006-11-29 2012-06-21 Tsutomu Furuhashi Liquid Crystal Display Device With Touch Screen
US9081449B2 (en) * 2006-11-29 2015-07-14 Japan Display Inc. Liquid crystal display device with touch screen
US8127046B2 (en) 2006-12-04 2012-02-28 Deka Products Limited Partnership Medical device including a capacitive slider assembly that provides output signals wirelessly to one or more remote medical systems components
US20080165159A1 (en) * 2006-12-14 2008-07-10 Soss David A Force-based input device having a modular sensing component
US20080289887A1 (en) * 2007-05-22 2008-11-27 Qsi Corporation System and method for reducing vibrational effects on a force-based touch panel
US20080303800A1 (en) * 2007-05-22 2008-12-11 Elwell James K Touch-based input device providing a reconfigurable user interface
US20080289884A1 (en) * 2007-05-22 2008-11-27 Elwell James K Touch-Based Input Device with Boundary Defining a Void
US20080289885A1 (en) * 2007-05-22 2008-11-27 Elwell James K Force-Based Input Device Having a Dynamic User Interface
US9654104B2 (en) 2007-07-17 2017-05-16 Apple Inc. Resistive force sensor with capacitive discrimination
US20090020343A1 (en) * 2007-07-17 2009-01-22 Apple Inc. Resistive force sensor with capacitive discrimination
US20090019949A1 (en) * 2007-07-17 2009-01-22 Apple Inc. Resistive force sensor with capacitive discrimination
US9001049B2 (en) 2007-07-19 2015-04-07 Volkswagen Ag Method for determining the position of an actuation element, in particular a finger of a user in a motor vehicle and position determination device
WO2009010308A1 (en) * 2007-07-19 2009-01-22 Volkswagen Ag Method for determining the position of an actuation element, in particular a finger of a user in a motor vehicle and position determination device
US20110175843A1 (en) * 2007-07-19 2011-07-21 Bachfischer Katharina Method for determining the position of an actuation element, in particular a finger of a user in a motor vehicle and position determination device
TWI463380B (en) * 2007-09-06 2014-12-01 Cypress Semiconductor Corp Calibration of single-layer touch-sensor device
US8248081B2 (en) * 2007-09-06 2012-08-21 Cypress Semiconductor Corporation Calibration of single-layer touch-sensor device
US20090066674A1 (en) * 2007-09-06 2009-03-12 Andriy Maharyta Calibration of single-layer touch-sensor device
US9292122B1 (en) 2007-09-06 2016-03-22 Cypress Semiconductor Corporation Calibration of a touch-sensor device
US8941475B2 (en) 2007-09-18 2015-01-27 Senseg Oy Method and apparatus for sensory stimulation
US9454880B2 (en) 2007-09-18 2016-09-27 Senseg Oy Method and apparatus for sensory stimulation
US20090174675A1 (en) * 2008-01-09 2009-07-09 Dave Gillespie Locating multiple objects on a capacitive touch pad
US10078408B2 (en) 2008-02-28 2018-09-18 3M Innovative Properties Company Touch screen sensor
EP2260366A4 (en) * 2008-02-28 2014-10-08 3M Innovative Properties Co Touch screen sensor having varying sheet resistance
US10101868B1 (en) 2008-02-28 2018-10-16 3M Innovative Properties Company Touch screen sensor
US8508680B2 (en) 2008-02-28 2013-08-13 3M Innovative Properties Company Touch screen sensor with low visibility conductors
WO2009108765A3 (en) * 2008-02-28 2009-11-19 3M Innovative Properties Company Touch screen sensor having varying sheet resistance
US10114516B1 (en) 2008-02-28 2018-10-30 3M Innovative Properties Company Touch screen sensor
US10126901B1 (en) 2008-02-28 2018-11-13 3M Innovative Properties Company Touch screen sensor
US9487040B2 (en) 2008-02-28 2016-11-08 3M Innovative Properties Company Methods of patterning a conductor on a substrate
US8274494B2 (en) 2008-02-28 2012-09-25 3M Innovative Properties Company Touch screen sensor having varying sheet resistance
US8704799B2 (en) 2008-02-28 2014-04-22 3M Innovative Properties Company Touch screen sensor having varying sheet resistance
US8932475B2 (en) 2008-02-28 2015-01-13 3M Innovative Properties Company Methods of patterning a conductor on a substrate
EP2260366A2 (en) * 2008-02-28 2010-12-15 3M Innovative Properties Company Touch screen sensor having varying sheet resistance
US9823786B2 (en) 2008-02-28 2017-11-21 3M Innovative Properties Company Touch screen sensor
US20100156840A1 (en) * 2008-02-28 2010-06-24 Frey Matthew H Touch screen sensor having varying sheet resistance
US8384691B2 (en) 2008-02-28 2013-02-26 3M Innovative Properties Company Touch screen sensor
US20090218310A1 (en) * 2008-02-28 2009-09-03 Lijun Zu Methods of patterning a conductor on a substrate
US8425792B2 (en) 2008-02-28 2013-04-23 3M Innovative Properties Company Methods of patterning a conductor on a substrate
US20090273571A1 (en) * 2008-05-01 2009-11-05 Alan Bowens Gesture Recognition
US8526767B2 (en) 2008-05-01 2013-09-03 Atmel Corporation Gesture recognition
DE102009019910A1 (en) 2008-05-01 2009-12-03 Atmel Corporation, San Jose Touch sensor device e.g. capacitive touch sensor device, for e.g. personal computer, has gesture unit analyzing time series data to distinguish gesture inputs, where unit is coded with gesture recognition code having linked state modules
US9122947B2 (en) 2008-05-01 2015-09-01 Atmel Corporation Gesture recognition
US20110074733A1 (en) * 2008-05-19 2011-03-31 Maekinen Ville Interface apparatus for touch input and tactile output communication
US9123258B2 (en) * 2008-05-19 2015-09-01 Senseg Ltd. Interface apparatus for touch input and tactile output communication
US20100045620A1 (en) * 2008-07-23 2010-02-25 Ding Hua Long Integration design for capacitive touch panels and liquid crystal displays
US8228306B2 (en) 2008-07-23 2012-07-24 Flextronics Ap, Llc Integration design for capacitive touch panels and liquid crystal displays
US20100026659A1 (en) * 2008-07-30 2010-02-04 Flextronics Ap, Llc Glass substrate for capacitive touch panel and manufacturing method thereof
US9128568B2 (en) 2008-07-30 2015-09-08 New Vision Display (Shenzhen) Co., Limited Capacitive touch panel with FPC connector electrically coupled to conductive traces of face-to-face ITO pattern structure in single plane
US20090219258A1 (en) * 2008-08-01 2009-09-03 3M Innovative Properties Company Touch screen sensor with low visibility conductors
US8284332B2 (en) 2008-08-01 2012-10-09 3M Innovative Properties Company Touch screen sensor with low visibility conductors
US8462127B2 (en) * 2008-08-05 2013-06-11 Elan Microelectronics Corp. Touch screen and method for positioning coordinate
US20100033449A1 (en) * 2008-08-05 2010-02-11 Yen-Chen Chiu Touch screen and method for positioning coordinate
US20110156800A1 (en) * 2008-09-19 2011-06-30 Atlab Inc. Sensor, sensing method thereof, and filter therefor
US9927924B2 (en) 2008-09-26 2018-03-27 Apple Inc. Differential sensing for a touch panel
US8507800B2 (en) 2008-12-05 2013-08-13 Multek Display (Hong Kong) Limited Capacitive touch panel having dual resistive layer
US8209861B2 (en) 2008-12-05 2012-07-03 Flextronics Ap, Llc Method for manufacturing a touch screen sensor assembly
US20100139955A1 (en) * 2008-12-05 2010-06-10 Ding Hua Long Capacitive touch panel having dual resistive layer
US20100156810A1 (en) * 2008-12-22 2010-06-24 Fabrice Barbier Diamond pattern on a single layer
US8274486B2 (en) 2008-12-22 2012-09-25 Flextronics Ap, Llc Diamond pattern on a single layer
US20100156811A1 (en) * 2008-12-22 2010-06-24 Ding Hua Long New pattern design for a capacitive touch screen
US20100156846A1 (en) * 2008-12-23 2010-06-24 Flextronics Ap, Llc Single substrate capacitive touch panel
US20100214225A1 (en) * 2009-02-26 2010-08-26 Research In Motion Limited Method for and apparatus for display scrolling
US20100220063A1 (en) * 2009-02-27 2010-09-02 Panasonic Corporation System and methods for calibratable translation of position
US20100327881A1 (en) * 2009-06-24 2010-12-30 Chin-Fu Chang Control unit, sensing device for a capacitive touch panel and method therefor
US8976122B2 (en) * 2009-06-24 2015-03-10 Egalax—Empia Technology Inc. Control unit, sensing device for a capacitive touch panel and method therefor
US20150138152A1 (en) * 2009-06-24 2015-05-21 Egalax_Empia Technology Inc. Control unit, sensing device for a capacitive touch panel and method thereof
US20110001717A1 (en) * 2009-07-06 2011-01-06 Charles Hayes Narrow Border for Capacitive Touch Panels
EP2275911A3 (en) * 2009-07-10 2011-06-08 Chimei InnoLux Corporation Touch panel and multi-touch detecting method thereof
US8723817B2 (en) 2009-09-08 2014-05-13 Au Optronics Corp. Touch-sensing structure for touch panel and touch-sensing method thereof
US20110057898A1 (en) * 2009-09-08 2011-03-10 Au Optronics Corp. Touch-sensing structure for touch panel and touch-sensing method thereof
US20140057102A1 (en) * 2009-09-28 2014-02-27 Lg Chem, Ltd. Touch panel
US20120244348A1 (en) * 2009-09-28 2012-09-27 Lg Chem, Ltd. Touch panel
US8600698B2 (en) 2009-10-09 2013-12-03 Egalax—Empia Technology Inc. Method and device for analyzing positions
US8890821B2 (en) 2009-10-09 2014-11-18 Egalax—Empia Technology Inc. Method and device for dual-differential sensing
US20110084930A1 (en) * 2009-10-09 2011-04-14 Egalax_Empia Technology Inc. Method and device for dual-differential sensing
US9141216B2 (en) 2009-10-09 2015-09-22 Egalax—Empia Technology Inc. Method and device for dual-differential sensing
US8842079B2 (en) 2009-10-09 2014-09-23 Egalax—Empia Technology Inc. Method and device for determining a touch or touches
US9483152B2 (en) 2009-10-09 2016-11-01 Egalax_Empia Technology Inc. Method and device for dual-differential sensing
US20110084927A1 (en) * 2009-10-09 2011-04-14 Egalax_Empia Technology Inc. Method and device for determining a touch or touches
US10101372B2 (en) 2009-10-09 2018-10-16 Egalax_Empia Technology Inc. Method and device for analyzing positions
US8816979B2 (en) 2009-10-09 2014-08-26 Egalax—Empia Technology Inc. Method and device for determining a touch or touches
US9798427B2 (en) 2009-10-09 2017-10-24 Egalax_Empia Technology Inc. Method and device for dual-differential sensing
US8583401B2 (en) 2009-10-09 2013-11-12 Egalax—Empia Technology Inc. Method and device for analyzing positions
US8643613B2 (en) 2009-10-09 2014-02-04 Egalax—Empia Technology Inc. Method and device for dual-differential sensing
US20110087455A1 (en) * 2009-10-09 2011-04-14 Egalax_Empia Technology Inc. Method and device for analyzing positions
US20110109588A1 (en) * 2009-11-12 2011-05-12 Senseg Ltd. Tactile stimulation apparatus having a composite section comprising a semiconducting material
US8766933B2 (en) 2009-11-12 2014-07-01 Senseg Ltd. Tactile stimulation apparatus having a composite section comprising a semiconducting material
US9063572B2 (en) 2009-11-12 2015-06-23 Senseg Ltd. Tactile stimulation apparatus having a composite section comprising a semiconducting material
US20110157067A1 (en) * 2009-12-31 2011-06-30 Motorola, Inc. Duty cycle modulation of periodic time-synchronous receivers for noise reduction
US9298303B2 (en) 2009-12-31 2016-03-29 Google Technology Holdings LLC Duty cycle modulation of periodic time-synchronous receivers for noise reduction
US20110216035A1 (en) * 2010-03-03 2011-09-08 Chimei Innolux Corporation Surface capacitive touch panel, driving method thereof and electronic apparatus using the same
US9285929B2 (en) 2010-03-30 2016-03-15 New Vision Display (Shenzhen) Co., Limited Touchscreen system with simplified mechanical touchscreen design using capacitance and acoustic sensing technologies, and method therefor
US9401750B2 (en) 2010-05-05 2016-07-26 Google Technology Holdings LLC Method and precoder information feedback in multi-antenna wireless communication systems
US20160018946A1 (en) * 2010-06-07 2016-01-21 Apple Inc. Touch sensing error compensation
US10185443B2 (en) * 2010-06-07 2019-01-22 Apple Inc. Touch sensing error compensation
US8531433B2 (en) 2010-07-21 2013-09-10 Synaptics Incorporated Producing capacitive images comprising non-connection values
CN102478988A (en) * 2010-11-26 2012-05-30 奇美电子股份有限公司 Method for detecting touch point on touch screen
US9841840B2 (en) 2011-02-07 2017-12-12 Parade Technologies, Ltd. Noise filtering devices, systems and methods for capacitance sensing devices
WO2013009778A1 (en) * 2011-07-14 2013-01-17 Apple Inc. Combined force and proximity sensing
CN102999193A (en) * 2011-09-13 2013-03-27 天津富纳源创科技有限公司 Touch screen touch point detection method
US20130135249A1 (en) * 2011-11-25 2013-05-30 Shih Hua Technology Ltd. Capacitive touch panel, driving method for preventing leakage current
US20140333583A1 (en) * 2012-01-31 2014-11-13 Fujitsu Component Limited Position detection method in touch panel and touch panel
US8525955B2 (en) 2012-01-31 2013-09-03 Multek Display (Hong Kong) Limited Heater for liquid crystal display
US9939967B2 (en) * 2012-01-31 2018-04-10 Fujitsu Component Limited Position detection method in touch panel and touch panel
US9444452B2 (en) 2012-02-24 2016-09-13 Parade Technologies, Ltd. Frequency hopping algorithm for capacitance sensing devices
US10020963B2 (en) 2012-12-03 2018-07-10 Google Technology Holdings LLC Method and apparatus for selectively transmitting data using spatial diversity
US9813262B2 (en) 2012-12-03 2017-11-07 Google Technology Holdings LLC Method and apparatus for selectively transmitting data using spatial diversity
US9591508B2 (en) 2012-12-20 2017-03-07 Google Technology Holdings LLC Methods and apparatus for transmitting data between different peer-to-peer communication groups
US9979531B2 (en) 2013-01-03 2018-05-22 Google Technology Holdings LLC Method and apparatus for tuning a communication device for multi band operation
US9921668B1 (en) * 2013-01-25 2018-03-20 Qualcomm Incorporated Touch panel controller integrated with host processor for dynamic baseline image update
US10229697B2 (en) 2013-03-12 2019-03-12 Google Technology Holdings LLC Apparatus and method for beamforming to obtain voice and noise signals
US20150002440A1 (en) * 2013-06-26 2015-01-01 Tianjin Funayuanchuang Technology Co., Ltd. Method and apparatus for determining touch point coordinates on a touch panel with anisotropic films
US9360973B2 (en) * 2013-06-26 2016-06-07 Tianjin Funayuanchuang Technology Co., Ltd. Method and apparatus for determining touch point coordinates on a touch panel with anisotropic films
US9687059B2 (en) * 2013-08-23 2017-06-27 Preemadonna Inc. Nail decorating apparatus
US9386542B2 (en) 2013-09-19 2016-07-05 Google Technology Holdings, LLC Method and apparatus for estimating transmit power of a wireless device
US20150145795A1 (en) * 2013-11-28 2015-05-28 Tianjim Funayuanchuang Technology Co., Ltd. Method for controlling touch panel
US9549290B2 (en) 2013-12-19 2017-01-17 Google Technology Holdings LLC Method and apparatus for determining direction information for a wireless device
US9491007B2 (en) 2014-04-28 2016-11-08 Google Technology Holdings LLC Apparatus and method for antenna matching
US9478847B2 (en) 2014-06-02 2016-10-25 Google Technology Holdings LLC Antenna system and method of assembly for a wearable electronic device
WO2016014132A1 (en) * 2014-07-23 2016-01-28 Preemadonna Inc. Apparatus for applying coating to nails
GB2546672B (en) * 2014-07-23 2019-01-02 Preemadonna Inc Apparatus for applying coating to nails
GB2546672A (en) * 2014-07-23 2017-07-26 Preemadonna Inc Apparatus for applying coating to nails
US9886157B2 (en) 2014-12-02 2018-02-06 Fujitsu Component Limited Touch panel device and method of correcting coordinates on touch panel
US20160239699A1 (en) * 2015-02-16 2016-08-18 Xintec Inc. Chip scale sensing chip package and a manufacturing method thereof

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