WO2022066173A1 - Electronic devices with touch sensors having overlaid projected-capacitive layers - Google Patents

Electronic devices with touch sensors having overlaid projected-capacitive layers Download PDF

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Publication number
WO2022066173A1
WO2022066173A1 PCT/US2020/052926 US2020052926W WO2022066173A1 WO 2022066173 A1 WO2022066173 A1 WO 2022066173A1 US 2020052926 W US2020052926 W US 2020052926W WO 2022066173 A1 WO2022066173 A1 WO 2022066173A1
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WO
WIPO (PCT)
Prior art keywords
arrangement
touch sensor
input
capacitive nodes
layer
Prior art date
Application number
PCT/US2020/052926
Other languages
French (fr)
Inventor
Fred Charles Thomas Iii
Charles J. Stancil
Original Assignee
Hewlett-Packard Development Company, L.P.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hewlett-Packard Development Company, L.P. filed Critical Hewlett-Packard Development Company, L.P.
Priority to PCT/US2020/052926 priority Critical patent/WO2022066173A1/en
Publication of WO2022066173A1 publication Critical patent/WO2022066173A1/en

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input 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
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
    • G06F3/0445—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input 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
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
    • G06F3/0442—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input 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
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
    • G06F3/0446—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input 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
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
    • G06F3/0448—Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2203/00—Indexing scheme relating to G06F3/00 - G06F3/048
    • G06F2203/041—Indexing scheme relating to G06F3/041 - G06F3/045
    • G06F2203/04102—Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper

Definitions

  • Electronic devices such as non-display-integrated indirect inking tablets, display-integrated tablets and laptops may include touch sensors to detect input to the sensors, such as ioput from a finger of a user, from an electromagnetic pen, an electrostatic pen, or the like.
  • FIG. 1 A is a block diagram of an example electronic device with a touch sensor having overlaid projected-capacitive layers.
  • FIG. 1 B is an isometric, partially exploded view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A.
  • FIG. 1 C is an isometric view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A depicting an offset between the layers.
  • FIG. 1 D is a top view of the off the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A depicting the offset between the layers.
  • FIG. 1 E is an exploded view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A.
  • FIG. 2A is a top view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A with fiducial markers for alignment.
  • FIG. 2B is a top view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A with alignment sensors for alignment.
  • FIG. 3 is a block diagram of another example electronic device with a touch sensor having overlaid projected-capacitive layers.
  • FIG. 4 is a schematic diagram of an electromagnetic pen interacting with the touch sensor of FIG. 3.
  • FIG. 5 is a block diagram of another example electronic device with a touch sensor having overlaid projected-capacitive layers.
  • FIG. 6 is a top view of a sheet supporting the projected-capacitive layers in a flattened state.
  • Electronic devices may include touch sensors to receive input from users.
  • the touch sensors may be projected-capacitive sensors, which utilize a change in capacitance of the touch sensors’ arrayed capacitive nodes to detect the input.
  • Some touch sensors may lack resolution for fine input based on manufacturing capabilities and cost restrictions for manufacturing higher resolution sensors. Additionally, touch sensors generally simply detect the location of the input, and do not provide additional information, such as the tilt or rotation of the input device.
  • An example electronic device includes a display device, a controller, and a touch sensor having overlaid projected-capacitive layers, in a nondisplay-integrated indirect inking tablet or device, the touch sensor and the display device may be separate (i.e., not overlaid with one another).
  • the overlaid layers are spaced to increase the input detection capability of the touch sensor. For example, the overlaid layers may be laterally offset from one another to increase the effective resolution of the touch sensor, relative to either layer individually.
  • the controller may combine the capacitance signals from the two layers, for example by overlaying them to determine the location of the input.
  • the overlaid layers may additionally be spaced apart to define a gap therebetween (e.g., by an electrically insulating spacer). The vertical spacing of the overlaid layers may allow the controller to determine a tilt and rotation of an electromagnetic input.
  • the controller may apply sigma-delta sampling to the capacitance signals received from the layers to improve noise filtering and allow more accurate location determination.
  • FIG. 1 A shows a block diagram of an electronic device 100, such as a laptop or notebook computer, a tablet, or an electronic pen sensor.
  • the electronic device 100 includes a display device 102, a controller 104 and a touch sensor 106.
  • the display device 102 may be a liquid crystal display (LCD), a lightemitting diode (LED) display, an organic light-emitting diode (OLED) display, or the like.
  • the display device 102 is generally to display a representation of the input to the touch sensor 106.
  • the controller 104 may include a central processing unit (CPU), a microcontroller, a microprocessor, a processing core, a field-programmable gate array (FPGA), a circuit, a microchip, a chipset, or similar device capable of executing machine-readable instructions.
  • the controller 104 may cooperate with a memory to execute instructions.
  • Memory may include a non-transitory machine-readable storage medium that may be may electronic, magnetic, optical, or other physical storage device that stores executable instructions.
  • the machine-readable storage medium may include, for example, random access memory (RAM), read-only memory (ROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, a storage drive, an optical disc, and the like.
  • the machine-readable storage medium may be encoded with executable instructions.
  • the controller 104 may include appropriate signal line drivers for a projected-capacitive array, and may be configured with sigma-delta based analog-to-digital converters.
  • the touch sensor 106 is a projected-capacitive touch sensor to detect inputs from a source such as a finger of a user, an electromagnetic pen, or other suitable sources which affect the capacitance of the touch sensor 106.
  • the touch sensor 106 includes a first projected-capacitive layer 108 and a second projected-capacitive layer 110.
  • Each of the first and second projected-capacitive layers 108 and 1 10 may function as a touch sensor itself, having suitable capacitive nodes in configurations to detect the location of an input on the respective layer.
  • the first and second layers 108 and 1 10 are thus overlaid in the touch sensor 106 to increase an effective resolution of the touch sensor 106, as compared to either the first layer 108 or the second layer 110, or to enable additional tilt and rotation detection functionality, as described in further detail below.
  • FIG. 1 B an isometric view of the touch sensor 106 including the first projected-capacitive layer 108 and the second projected- capacitive layer 110 is depicted.
  • the first layer 108 includes a first arrangement 112 of capacitive nodes and the second layer 110 includes a second arrangement 114 of capacitive nodes.
  • the second layer 110 is overlaid on the first layer 108 to offset the second arrangement 114 of capacitive nodes from the first arrangement 112 of capacitive nodes to increase the effective resolution of the touch sensor 106, as compared to either the first layer 108 or the second layer 110.
  • the increase in effective resolution may be achieved without incurring higher manufacturing costs to create a higher resolution single layer.
  • FIGS. 1 C and 1 D depict, respectively, an isometric view and a top view of the touch sensor 106 illustrating the offset of the first arrangement 1 12 and the second arrangement 114 of capacitive nodes.
  • the first layer 108 includes a first arrangement 112 of capacitive nodes.
  • the first arrangement 112 is an array of capacitive nodes connected in rows and columns.
  • the second layer 110 includes a second arrangement 114 of capacitive nodes.
  • the second arrangement 114 may also be an array of capacitive nodes connected in rows and columns.
  • the second arrangement 114 may be an array of substantially the same dimensions (i.e., having substantially the same size of capacitive nodes, size of array and substantially the same pitch between capacitive nodes).
  • the second layer 1 10 is overlaid on the first layer 108 such that the second arrangement 114 of capacitive nodes is offset from the first arrangement 112 of capacitive nodes.
  • the second arrangement 114 may be offset from the first arrangement 112 by about half a pitch between the capacitive nodes of the first arrangement 112, as can be seen in FIG. 1 D.
  • each capacitive node of the second arrangement 114 is offset by half a pitch in the X direction and the Y direction from the capacitive nodes of the first arrangement 112.
  • the first layer 108 and the second layer 1 10 may each include drive electrodes and sense electrodes to detect capacitance changes.
  • FIG. 1 E an exploded view of the touch sensor 106 is depicted.
  • the first layer 108 may be arranged such that the rows of capacitive nodes serve as drive electrodes 1 16, while the columns of capacitive nodes serve as sense electrodes 118. Accordingly, to avoid interference between the drive electrodes 116 and the sense electrodes 118, the first layer 108 additionally includes an electrically insulating sheet 120. That is, the drive electrodes 1 16 may be supported on a first side of the sheet 120, while the sense electrodes 118 are disposed on a second side of the sheet 120 (i.e., opposite the first side). Together, the drive electrodes 1 16, the sheet 120, and the sense electrodes 118 form the first layer 108.
  • the sheet 120 may be formed of PET (polyester) having etched PEDOT (poly(3,4- ethylenedioxythiophene)) drive electrodes 116 and sense electrodes 1 18.
  • the drive electrodes 116 and the sense electrodes 118 may be fabricated photolithographically using indium tin oxide or other suitable materials for forming a projected-capacitive touch sensor.
  • the examples above may use optically clear electrode materials for use in a display-integrated tablet or laptop, where the display device 102 is to be visible through the touch sensor 106.
  • Opaque electrode materials such as copper, sliver, and the like may be used for non-display-integrated indirect inking tablets.
  • the second layer 110 may similarly be arranged such that the rows of capacitive nodes serve as drive electrodes 122, while the columns of capacitive nodes serve as sense electrodes 124.
  • the second layer 110 additionally includes an electrically insulating sheet 126. That is, the drive electrodes 122 are supported on a first side of the sheet 126 while the sense electrodes 124 are disposed on a second side of the sheet 126 (i.e., opposite the first side). Together, the drive electrodes 122, the sheet 126, and the sense electrodes 124 form the second layer 110.
  • the sheet 126 may similarly be formed of PET having etched PEDOT drive electrodes 122 and sense electrodes 124.
  • the drive electrodes 122 and the sense electrodes 124 may be fabricated photoiithographically using indium tin oxide or other suitable materials for forming a projected-capacitive touch sensor.
  • these examples may use optically clear electrode materials for use in a display-integrated tablet or laptop, where the display device 102 is to be visible through the touch sensor 106.
  • Opaque electrode materials such as copper, silver, and the like may be used for non-display-integrated indirect inking tablets.
  • the first layer 108 and the second layer 1 10 may additionally be spaced apart to define a gap therebetween to avoid electrical contact between the respective electrodes of the first layer 108 and the second layer 1 10.
  • the touch sensor 106 may include an electrically insulating spacer disposed in the gap between the first layer 108 and the second layer 1 10.
  • the capacitance of the capacitive nodes is altered.
  • the first layer 108 may output a first capacitance signal representing the input as detected by the first layer 108.
  • the second layer 110 may output a second capacitance signal representing the input as detected by the second layer 110.
  • the controller 104 receives the first capacitance signal representing the input to the touch sensor as detected by the first layer 108 and the second capacitance signal representing the input to the touch sensor as detected by the second layer 110 and combines the first capacitance signal and the second capacitance signal to determine a location of the input on the touch sensor 106.
  • the controller 104 may overlay the first capacitance signal and the second capacitance signal based on the relative geometrical relationship of the first layer 108 and the second layer 110 to determine the location of the input. Since the first arrangement 1 12 and the second arrangement 1 14 are offset, the first capacitance signal and the second capacitance signal may provide different information to the controller 104 about the location of the input.
  • an input when an input is received between capacitive nodes of the first arrangement 112, such an input may be detected with greater accuracy by the second arrangement 114 (e.g., as represented by a stronger or more distinct peak in the second capacitance signal relative to the first capacitance signal).
  • the controller 104 may apply sigma-delta sampling to the first capacitance signal and the second capacitance signal to reduce the noise extracted from the first and second capacitance signals, and hence increase the quality of the resulting signal.
  • the controller 104 may then combine the sigmadelta sampled first and capacitance signals to determine the location of the input on the touch sensor 106.
  • the controller 104 may display a representation of the location of the input at the display device 102.
  • the location of the input may be represented as a dot.
  • the controller 104 may additionally represent the locations of inputs over time as a line or stroke.
  • the controller 104 may apply a machine learning model to the first and second capacitance signals to determine the change and flux of the first and capacitance signals over time to assist in rendering the line or stroke.
  • the controller 104 may determine a motion of the input on the touch sensor 106 (e.g., tilt, rotation) to inform the representation of the line or stroke to display at the display device 102.
  • the motion of the input may affect the stroke width, curvature, intensity, and the like.
  • the touch sensor 106 may be overlaid on the display device 102 (e.g., as in a display-integrated tablet) to display the location of the input, in other examples, the touch sensor 106 may be an indirect sensing mechanism (e.g., a non-display-integrated indirect inking device) to detect the input and display the location of the input at the display device 102 independent from the touch sensor 106.
  • an indirect sensing mechanism e.g., a non-display-integrated indirect inking device
  • the first layer 108 and the second layer 110 may include fiducial marks, alignment sensors, or other alignment mechanisms.
  • the first layer 108 includes a first fiducial mark 200
  • the second layer 110 includes a second fiducial mark 202.
  • the first fiducial mark 200 a cross in the present example
  • the second arrangement 114 of capacitive nodes is offset from the first arrangement 1 12 of capacitive nodes by half the pitch of the first arrangement of capacitive nodes.
  • the fiducial marks 200 and 202 may be used for example, by an operator to manually align the first layer 108 and the second layer 1 10, or to perform a quality assessment of the alignment between the first layer 108 and the second layer 110. In other examples, other shapes or patterns of fiducial marks may be utilized. Additionally, more than one fiducial mark may be used, for example in each of four comers of the first and second layers 108 and 1 10 to align the first and second layers 108 and 110.
  • the first layer 108 includes a first alignment sensor 210
  • the second layer 110 includes a second alignment sensor 212.
  • the second arrangement 1 14 of capacitive nodes is offset from the first arrangement 112 of capacitive nodes by half the pitch of the first arrangement of capacitive nodes.
  • the first and second alignment sensors 210 and 212 may be capacitive nodes themselves, and hence may form a stacked capacitor 214. Accordingly, the controller 104 may measure an alignment capacitance of the stacked capacitor 214 to determine an alignment of the first and second alignment sensors 210 and 212.
  • the measured alignment capacitance may be compared to a predefined target alignment capacitance; if the measured alignment capacitance is within a threshold tolerance of the target alignment capacitance, the alignment sensors 210 and 212 may be determined to be aligned, in other examples, an alternate controller (e.g., independent of the electronic device 100) may connect to and measure the alignment capacitance of the stacked capacitor 214.
  • an alternate controller e.g., independent of the electronic device 100
  • the alignment sensors 210 and 212 are not aligned, and hence the measured alignment capacitance of the stacked capacitor 214 may be outside the threshold tolerance from the target alignment capacitance.
  • more than one alignment sensor may be used, for example, in each of the four corners of the first and second layers 108 and 110, or in a triangular or other pattern in a designated region of the first and second layers 108 and 1 10.
  • the alignment capacitance of each of the stacked capacitors formed from the alignment sensors may be used to align the first and second layers 108 and 1 10.
  • the electronic device 300 may be a laptop or notebook computer, a tablet, an electronic pen sensor, or the like.
  • the electronic device 300 includes a display device 302, a controller 304, and a projected-capacitive touch sensor 306.
  • the display device 302 is similar to the display device 102 and is generally to display a representation of an input to the touch sensor 306.
  • the display device may be a LCD display, an LED display, an OLED display, or the like.
  • the controller 304 is similar to the controller 104, and may include a central processing unit (CPU), a microcontroller, a microprocessor, a processing core, a field-programmable gate array (FPGA), a circuit, a microchip, a chipset, or similar device capable of executing machine-readable instructions.
  • the controller 304 may cooperate with a memory to execute instructions.
  • Memory may include a non-transitory machine-readable storage medium that may be may electronic, magnetic, optical, or other physical storage device that stores executable instructions.
  • the machine-readable storage medium may include, for example, random access memory (RAM), read-only memory (ROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, a storage drive, an optical disc, and the like.
  • the machine-readable storage medium may be encoded with executable instructions.
  • the controller 104 may include appropriate signal line drivers for a projected-capacitive array, and may be configured with sigma-delta based analog-to-digltal converters.
  • the touch sensor 306 is similar to the touch sensor 106.
  • the touch sensor 306 is a projected-capacitive touch sensor to detect inputs from a source such as a finger of a user, an electromagnetic pen, or other suitable sources which affect the capacitance of the touch sensor 306.
  • the touch sensor 306 includes a first projected-capacitive layer 308 and a second projected-capacitive layer 310.
  • Each of the first layer 308 and the second layer 310 may function as a touch sensor itself, having suitable capacitive nodes in configurations to detect the location of an input on the respective layer. That is, the first layer 308 includes first capacitive nodes (e.g., arranged in a first arrangement, as in the first layer 108) to generate a first capacitance signal in response to an electromagnetic Input to the touch sensor 306. Similarly, the second layer 310 includes second capacitive nodes (e.g., arranged in a second arrangement, as in the second layer 110) to generate a second capacitance signal in response to the input to the touch sensor 306.
  • first capacitive nodes e.g., arranged in a first arrangement, as in the first layer 108
  • second capacitive nodes e.g., arranged in a second arrangement, as in the second layer 110
  • the second layer 310 is overlaid on the first layer 308 and is spaced apart from the first layer 308 to define a gap therebetween.
  • the touch sensor 306 includes an electrically insulating spacer 312 disposed in the gap between the first layer 308 and the second layer 310 to space the first layer 308 apart from the second layer 310.
  • the spacer 312 may be a plastic or glass material.
  • the spacer 312 may be about an order of magnitude thicker than the first and second layers 308 and 310.
  • the first and second layers 308 and 310 may be about 100 pm in thickness (e.g., a PET film), while the spacer 312 may be about 1 mm in thickness.
  • the capacitance of the capacitive nodes is altered.
  • the first layer 308 may output a first capacitance signal representing the input as detected by the first layer 308.
  • the second layer 310 may output a second capacitance signal representing the input as detected by the second layer 310.
  • the controller 304 receives the first capacitance signals representing the input as detected by the first layer 308 and the second capacitance signals representing the input as detected by the second layer 310.
  • the controller 304 may apply sigma-delta sampling to the first capacitance signal and the second capacitance signal to reduce the noise extracted from the first and second capacitance signals, and hence increase the quality of the resulting signals.
  • utilization of sigma-delta sampling may allow the first and second layers 308 and 310 to be spaced apart, while maintaining a sufficient quality of signal extracted from the first layer 308 (i.e., the layer at a greater distance from the input, and hence experiencing greater noise) to compute the location and the tilt of the input, as described below.
  • the controller 304 may then combine the first capacitance signal and the second capacitance signal to determine the location of the input on the touch sensor 306. Additionally, the controller 304 may compare the first capacitance signal and the second capacitance signal to determine a tilt of the electromagnetic input relative to the touch sensor 306.
  • the touch sensor 306 is depicted receiving an input from an electromagnetic pen 400.
  • the pen 400 emits electromagnetic waves 402 along a ray 404 extending through the length of the pen 400.
  • the electromagnetic waves 402 propagate from the ray 404 and interface with the first and second layers 308 and 310 of the touch sensor 306.
  • the electromagnetic waves 402 may generate the greatest change in capacitance along the ray 404. That is, the first layer 308 and the second layer 310 may detect different peaks of capacitance signals based on the direction of propagation of the ray 404 (i.e., based on the tilt of the pen 400). Accordingly, the first capacitance signal and the second capacitance signal may be compared and, in further consideration of the geometrical configuration (i.e., the height of the spacer 312 and/or the space defined between the first layer 308 and the second layer 310), used to determine the tilt of the pen 400. That is, the controller 304 may determine respective peaks from each of the first capacitance signal and the second capacitance signal and triangulate using the relative geometrical relationship between the first layer 308 and the second layer 310 to determine the tilt of the pen 400.
  • the geometrical configuration i.e., the height of the spacer 312 and/or the space defined between the first layer 308 and the second layer 310
  • the tilt of the pen 400 may affect the distribution of the capacitance signals detected by the first layer 308 and the second layer 310. Accordingly, the first and second capacitance signals may be combined and, in further consideration of the geometrical configuration and the determined tilt of the pen 400, used to determine a location of the electronic input relative to the touch sensor 306. Thus, both the location and tilt of the pen 400 may be determined based on signals detected by the touch sensor 306 itself, rather than using external sensors embedded, for example, in the pen 400.
  • the controller 304 may additionally, in some examples, apply a machine learning model to the first and second capacitance signals to determine the change and flux of the first and capacitance signals over time.
  • the controller 304 may determine a motion (e.g., tilt, rotation) of the pen 400 on the touch sensor 306.
  • the controller 304 may display a representation of the location of the input at the display device 302. For example, in a drawing application, the location of the input may be represented as a dot.
  • the controller 304 may additionally represent the locations of inputs over time as a line or stroke.
  • the motion of the input may inform the representation of the line or stroke to display at the display device 302. For example, the motion of the input may affect the stroke width, curvature, intensity, and the like.
  • FIG. 5 depicts another example electronic device 500 with overlaid projected-capacitive layers.
  • the electronic device 500 may be a laptop or notebook computer, a tablet, an electronic pen sensor, or the like.
  • the electronic device 500 includes a display device 502, a controller 504, and a projected-capacitive touch sensor 506.
  • the display device 502 is similar to the display device 102 and is generally to display a representation of an input to the touch sensor 506.
  • the display device may be a LCD display, an LED display, an OLED display, or the like.
  • the controller 504 is similar to the controller 104, and may include a central processing unit (CPU), a microcontroller, a microprocessor, a processing core, a field-programmable gate array (FPGA), a circuit, a microchip, a chipset, or similar device capable of executing machine-readable instructions.
  • the controller 504 may cooperate with a memory to execute instructions.
  • Memory may include a non-transitory machine-readable storage medium that may be may electronic, magnetic, optical, or other physical storage device that stores executable instructions.
  • the machine-readable storage medium may include, for example, random access memory (RAM), read-only memory (ROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, a storage drive, an optical disc, and the like.
  • the machine-readable storage medium may be encoded with executable instructions.
  • the controller 104 may include appropriate signal line drivers for a projected-capacitive array, and may be configured with sigma-delta based analog-to-digital converters.
  • the touch sensor 506 is a projected-capacitive touch sensor to detect inputs from a source such as a finger of a user, an electromagnetic pen, or other suitable sources which affect the capacitance of the touch sensor 506.
  • the touch sensor 506 includes a sheet 508 having a first portion 510 supporting a first arrangement of capacitive nodes, a second portion 512 supporting a second arrangement of capacitive nodes, and a folding portion 514 between the first portion 510 and the second portion 512.
  • the sheet 508 may be formed of PET having etched PEDOT electrodes to allow for the sheet 508 to be folded at the folding portion 514.
  • Each of the first portion and the second portion 512 may function as a touch sensor itself, having suitable arrangements of capacitive nodes to detect the location of an input on the respective portion.
  • the first and second portions 510 and 512 are overlaid to increase an effective resolution of the touch sensor 506 as compared to the first arrangement on the first portion 510 or the second arrangement on the second portion 512.
  • the sheet 508 folds at the folding portion 514 to overlay the second portion 512 on the first portion 510 such that the first arrangement of capacitive nodes is offset from the second arrangement of capacitive nodes.
  • the first and second arrangements of capacitive nodes may be arrays connected in rows and columns and having substantially the same dimensions.
  • the first and second arrangements of capacitive nodes may be offset by about half the pitch between the capacitive nodes. That is, when the sheet 508 is folded at the folding portion 514 to overlay the second portion 512 on the first portion 510, the capacitive nodes may be arranged similarly to the arrangement depicted in FIG. 1 D.
  • each of the first portion 510 and the second portion 512 may have drive electrodes and sense electrodes. Further, in some examples, the folding portion 514 may support electrical traces to couple the first arrangement of capacitive nodes to the second arrangement of capacitive nodes. For exampie, referring to FIG. 4, the sheet 508 is depicted in its flattened (i.e., not folded) state.
  • the sheet 508 includes a first arrangement 600 of capacitive nodes on the first portion 510 and a second arrangement 602 of capacitive nodes on the second portion 512.
  • the folding portion 514 supports electrical traces 604 coupling the first arrangement 600 to the second arrangement 602.
  • the drive lines and sense lines may extend from the second portion 512 across the folding portion 514 to the first portion 510.
  • the drive lines may be supported on a first side of the sheet 508, and the sense lines may be disposed on a second side of the sheet 508, opposite the first side.
  • the sheet 508 may then be folded at the folding portion 514.
  • the sensor 506 may therefore involve fewer drive channels (i.e., since drive lines from the first arrangement 600 and the second arrangement 602 are driven on the same channel) and generate fewer sense channels, resulting in a reduction in the number of data channels to process by the controller 504.
  • the first portion 510 and the second portion 512 may be spaced apart to define a gap therebetween to avoid electrical contact between the respective electrodes of the first portion 510 and the second portion 512.
  • the touch sensor 506 may include an electrically insulating spacer disposed in the gap between the first portion 510 and the second portion 512.
  • the sense electrodes may output a set of capacitance signals representing the input as detected by the first and second arrangements 600 and 602.
  • corresponding rows of drive electrodes of the first arrangement 600 and the second arrangement 602 are driven simultaneously as they correspond to the same drive line (i.e., as coupled by the electrical traces 604 on the folding portion.
  • corresponding columns of sense electrodes of the first arrangement 600 and second arrangement 602 may detect similar signals at different electrodes along the sense line.
  • the capacitance detected at the first portion 510 may correspond to a predefined portion (i.e., predefined capacitive nodes of the sense lines) of the capacitance signal detected by the sense electrodes.
  • the capacitance detected at the second portion 512 may correspond to another predefined portion (i.e., predefined capacitive nodes of the sense lines) of the capacitance signal detected by the touch sensor 506.
  • the controller 104 receives the set of capacitance signals representing the Input to the touch sensor 506.
  • the controller 104 may then resolve the set of capacitance signals into a first capacitance signal representing the input to the touch sensor 506 as detected by the first arrangement 600 of capacitive nodes (i.e., on the first portion 510) and a second capacitance signal representing the input to the touch sensor 506 as detected by the second arrangement 602 of capacitive nodes (i.e., on the second portion 512).
  • the controller 504 may apply sigma-delta sampling to the first capacitance signal and the second capacitance signal, or to the set of capacitance signals to reduce the noise extracted from the first and second capacitance signals, and hence increase the quality of the resulting signal.
  • the controller 504 may then combine the first capacitance signal and the second capacitance signal to determine the location of the input on the touch sensor 506.
  • the controller 504 may, in some examples apply a machine learning model to the first and second capacitance signals to determine the change and flux of the first and capacitance signals over time.
  • the controller 504 may determine a motion (e.g., tilt, rotation) of the input on the touch sensor 506.
  • the controller 504 may display a representation of the location of the input at the display device 502. For example, in a drawing application, the location of the input may be represented as a dot. In some examples, the controller 504 may additionally represent the locations of inputs over time as a line or stroke. In some examples, the motion of the input may inform the representation of the line or stroke to display at the display device 502. For example, the motion of the input may affect the stroke width, curvature, intensity, and the like.
  • an example electronic device includes a display device, a controller, and a touch sensor having overlaid projected-capacitive layers. Each layer generates a capacitance signal representing an input to the touch sensor as detected by the layer.
  • the capacitance signals from the layers may be combined to determine the location of the input on the touch sensor.
  • the layers may be offset, for example by half a pitch of the capacitance nodes on the layers, to increase an effective resolution of the touch sensor.
  • the layers may additionally be spaced apart to define a gap therebetween.
  • the capacitance signals from the layers may be compared to determine a tilt of the input, based on triangulation using the relative geometrical relationship of the layers.
  • the controller may apply sigma-delta sampling to improve noise filtering, and allowing the layers to be spaced apart for said tilt determination.
  • the layers may be supported on the same sheet, connected by a folding portion, with the capacitive nodes on each layer connected by electrical traces.
  • the number of data channels to drive and to sense the capacitance signal may be reduced.

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Abstract

An example electronic device includes: a display device; a touch sensor comprising: a first projected-capacitive layer comprising a first arrangement of capacitive nodes; and a second projected-capacitive layer comprising a second arrangement of capacitive nodes, wherein the second layer is overlaid on the first layer to offset the second arrangement of capacitive nodes from the first arrangement of capacitive nodes; and a controller connected to the touch sensor, the controller to: receive a first capacitance signal from the first arrangement of capacitive nodes representing an input to the touch sensor; receive a second capacitance signal from the second arrangement of capacitive nodes representing the input to the touch sensor; combine the first capacitance signal and the second capacitance signal to determine a location of the input on the touch sensor; and display the location of the input at the display device.

Description

ELECTRONIC DEVICES WITH TOUCH SENSORS HAVING OVERLAID
PROJECTED-CAPACITIVE LAYERS
BACKGROUND
[0001 ] Electronic devices, such as non-display-integrated indirect inking tablets, display-integrated tablets and laptops may include touch sensors to detect input to the sensors, such as ioput from a finger of a user, from an electromagnetic pen, an electrostatic pen, or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] FIG. 1 A is a block diagram of an example electronic device with a touch sensor having overlaid projected-capacitive layers.
[0003] FIG. 1 B is an isometric, partially exploded view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A.
[0004] FIG. 1 C is an isometric view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A depicting an offset between the layers.
[0005] FIG. 1 D is a top view of the off the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A depicting the offset between the layers.
[0006] FIG. 1 E is an exploded view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A.
[0007] FIG. 2A is a top view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A with fiducial markers for alignment.
[0008] FIG. 2B is a top view of the overlaid projected-capacitive layers of the touch sensor of FIG. 1 A with alignment sensors for alignment. [0009] FIG. 3 is a block diagram of another example electronic device with a touch sensor having overlaid projected-capacitive layers.
[0010] FIG. 4 is a schematic diagram of an electromagnetic pen interacting with the touch sensor of FIG. 3.
[0011 ] FIG. 5 is a block diagram of another example electronic device with a touch sensor having overlaid projected-capacitive layers.
[0012] FIG. 6 is a top view of a sheet supporting the projected-capacitive layers in a flattened state.
DETAILED DESCRIPTION
[0013] Electronic devices may include touch sensors to receive input from users. The touch sensors may be projected-capacitive sensors, which utilize a change in capacitance of the touch sensors’ arrayed capacitive nodes to detect the input. Some touch sensors may lack resolution for fine input based on manufacturing capabilities and cost restrictions for manufacturing higher resolution sensors. Additionally, touch sensors generally simply detect the location of the input, and do not provide additional information, such as the tilt or rotation of the input device.
[0014] An example electronic device includes a display device, a controller, and a touch sensor having overlaid projected-capacitive layers, in a nondisplay-integrated indirect inking tablet or device, the touch sensor and the display device may be separate (i.e., not overlaid with one another). The overlaid layers are spaced to increase the input detection capability of the touch sensor. For example, the overlaid layers may be laterally offset from one another to increase the effective resolution of the touch sensor, relative to either layer individually. The controller may combine the capacitance signals from the two layers, for example by overlaying them to determine the location of the input. The overlaid layers may additionally be spaced apart to define a gap therebetween (e.g., by an electrically insulating spacer). The vertical spacing of the overlaid layers may allow the controller to determine a tilt and rotation of an electromagnetic input. The controller may apply sigma-delta sampling to the capacitance signals received from the layers to improve noise filtering and allow more accurate location determination.
[0015] FIG. 1 A shows a block diagram of an electronic device 100, such as a laptop or notebook computer, a tablet, or an electronic pen sensor. The electronic device 100 includes a display device 102, a controller 104 and a touch sensor 106.
[0016] The display device 102 may be a liquid crystal display (LCD), a lightemitting diode (LED) display, an organic light-emitting diode (OLED) display, or the like. The display device 102 is generally to display a representation of the input to the touch sensor 106.
[0017] The controller 104 may include a central processing unit (CPU), a microcontroller, a microprocessor, a processing core, a field-programmable gate array (FPGA), a circuit, a microchip, a chipset, or similar device capable of executing machine-readable instructions. The controller 104 may cooperate with a memory to execute instructions. Memory may include a non-transitory machine-readable storage medium that may be may electronic, magnetic, optical, or other physical storage device that stores executable instructions. The machine-readable storage medium may include, for example, random access memory (RAM), read-only memory (ROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, a storage drive, an optical disc, and the like. The machine-readable storage medium may be encoded with executable instructions. The controller 104 may include appropriate signal line drivers for a projected-capacitive array, and may be configured with sigma-delta based analog-to-digital converters.
[0018] The touch sensor 106 is a projected-capacitive touch sensor to detect inputs from a source such as a finger of a user, an electromagnetic pen, or other suitable sources which affect the capacitance of the touch sensor 106. The touch sensor 106 includes a first projected-capacitive layer 108 and a second projected-capacitive layer 110. Each of the first and second projected-capacitive layers 108 and 1 10 may function as a touch sensor itself, having suitable capacitive nodes in configurations to detect the location of an input on the respective layer. The first and second layers 108 and 1 10 are thus overlaid in the touch sensor 106 to increase an effective resolution of the touch sensor 106, as compared to either the first layer 108 or the second layer 110, or to enable additional tilt and rotation detection functionality, as described in further detail below.
[0019] Referring to FIG. 1 B, an isometric view of the touch sensor 106 including the first projected-capacitive layer 108 and the second projected- capacitive layer 110 is depicted. The first layer 108 includes a first arrangement 112 of capacitive nodes and the second layer 110 includes a second arrangement 114 of capacitive nodes. The second layer 110 is overlaid on the first layer 108 to offset the second arrangement 114 of capacitive nodes from the first arrangement 112 of capacitive nodes to increase the effective resolution of the touch sensor 106, as compared to either the first layer 108 or the second layer 110. Advantageously, the increase in effective resolution may be achieved without incurring higher manufacturing costs to create a higher resolution single layer.
[0020] FIGS. 1 C and 1 D depict, respectively, an isometric view and a top view of the touch sensor 106 illustrating the offset of the first arrangement 1 12 and the second arrangement 114 of capacitive nodes. The first layer 108 includes a first arrangement 112 of capacitive nodes. In particular, the first arrangement 112 is an array of capacitive nodes connected in rows and columns. Similarly, the second layer 110 includes a second arrangement 114 of capacitive nodes. The second arrangement 114 may also be an array of capacitive nodes connected in rows and columns. In particular, the second arrangement 114 may be an array of substantially the same dimensions (i.e., having substantially the same size of capacitive nodes, size of array and substantially the same pitch between capacitive nodes). The second layer 1 10 is overlaid on the first layer 108 such that the second arrangement 114 of capacitive nodes is offset from the first arrangement 112 of capacitive nodes. For example, the second arrangement 114 may be offset from the first arrangement 112 by about half a pitch between the capacitive nodes of the first arrangement 112, as can be seen in FIG. 1 D. In particular, each capacitive node of the second arrangement 114 is offset by half a pitch in the X direction and the Y direction from the capacitive nodes of the first arrangement 112.
[0021 ] To detect the location of input at each respective layer, the first layer 108 and the second layer 1 10 may each include drive electrodes and sense electrodes to detect capacitance changes. For example, referring to FIG. 1 E, an exploded view of the touch sensor 106 is depicted.
[0022] The first layer 108 may be arranged such that the rows of capacitive nodes serve as drive electrodes 1 16, while the columns of capacitive nodes serve as sense electrodes 118. Accordingly, to avoid interference between the drive electrodes 116 and the sense electrodes 118, the first layer 108 additionally includes an electrically insulating sheet 120. That is, the drive electrodes 1 16 may be supported on a first side of the sheet 120, while the sense electrodes 118 are disposed on a second side of the sheet 120 (i.e., opposite the first side). Together, the drive electrodes 1 16, the sheet 120, and the sense electrodes 118 form the first layer 108. For example, the sheet 120 may be formed of PET (polyester) having etched PEDOT (poly(3,4- ethylenedioxythiophene)) drive electrodes 116 and sense electrodes 1 18. In other examples, the drive electrodes 116 and the sense electrodes 118 may be fabricated photolithographically using indium tin oxide or other suitable materials for forming a projected-capacitive touch sensor. The examples above may use optically clear electrode materials for use in a display-integrated tablet or laptop, where the display device 102 is to be visible through the touch sensor 106.
Opaque electrode materials such as copper, sliver, and the like may be used for non-display-integrated indirect inking tablets.
[0023] The second layer 110 may similarly be arranged such that the rows of capacitive nodes serve as drive electrodes 122, while the columns of capacitive nodes serve as sense electrodes 124. The second layer 110 additionally includes an electrically insulating sheet 126. That is, the drive electrodes 122 are supported on a first side of the sheet 126 while the sense electrodes 124 are disposed on a second side of the sheet 126 (i.e., opposite the first side). Together, the drive electrodes 122, the sheet 126, and the sense electrodes 124 form the second layer 110. The sheet 126 may similarly be formed of PET having etched PEDOT drive electrodes 122 and sense electrodes 124. In other examples, the drive electrodes 122 and the sense electrodes 124 may be fabricated photoiithographically using indium tin oxide or other suitable materials for forming a projected-capacitive touch sensor. Similarly, these examples may use optically clear electrode materials for use in a display-integrated tablet or laptop, where the display device 102 is to be visible through the touch sensor 106. Opaque electrode materials such as copper, silver, and the like may be used for non-display-integrated indirect inking tablets.
[0024] As will be appreciated, the first layer 108 and the second layer 1 10 may additionally be spaced apart to define a gap therebetween to avoid electrical contact between the respective electrodes of the first layer 108 and the second layer 1 10. In some examples, the touch sensor 106 may include an electrically insulating spacer disposed in the gap between the first layer 108 and the second layer 1 10.
[0025] in operation, when an input is received at the touch sensor 106, the capacitance of the capacitive nodes is altered. By alternating current driven through the drive electrodes 1 16 of capacitive nodes, the first layer 108 may output a first capacitance signal representing the input as detected by the first layer 108. Similarly, the second layer 110 may output a second capacitance signal representing the input as detected by the second layer 110.
[0026] The controller 104 receives the first capacitance signal representing the input to the touch sensor as detected by the first layer 108 and the second capacitance signal representing the input to the touch sensor as detected by the second layer 110 and combines the first capacitance signal and the second capacitance signal to determine a location of the input on the touch sensor 106. For example, the controller 104 may overlay the first capacitance signal and the second capacitance signal based on the relative geometrical relationship of the first layer 108 and the second layer 110 to determine the location of the input. Since the first arrangement 1 12 and the second arrangement 1 14 are offset, the first capacitance signal and the second capacitance signal may provide different information to the controller 104 about the location of the input. For example, when an input is received between capacitive nodes of the first arrangement 112, such an input may be detected with greater accuracy by the second arrangement 114 (e.g., as represented by a stronger or more distinct peak in the second capacitance signal relative to the first capacitance signal).
[0027] In some examples, prior to determining the location of the input on the touch sensor 106, the controller 104 may apply sigma-delta sampling to the first capacitance signal and the second capacitance signal to reduce the noise extracted from the first and second capacitance signals, and hence increase the quality of the resulting signal. The controller 104 may then combine the sigmadelta sampled first and capacitance signals to determine the location of the input on the touch sensor 106.
[0028] After having determined the location of the input, the controller 104 may display a representation of the location of the input at the display device 102. For example, in a drawing application, the location of the input may be represented as a dot. In some examples, the controller 104 may additionally represent the locations of inputs over time as a line or stroke. For example, the controller 104 may apply a machine learning model to the first and second capacitance signals to determine the change and flux of the first and capacitance signals over time to assist in rendering the line or stroke. In particular, the controller 104 may determine a motion of the input on the touch sensor 106 (e.g., tilt, rotation) to inform the representation of the line or stroke to display at the display device 102. For example, the motion of the input may affect the stroke width, curvature, intensity, and the like. [0029] In some examples, the touch sensor 106 may be overlaid on the display device 102 (e.g., as in a display-integrated tablet) to display the location of the input, in other examples, the touch sensor 106 may be an indirect sensing mechanism (e.g., a non-display-integrated indirect inking device) to detect the input and display the location of the input at the display device 102 independent from the touch sensor 106.
[0030] To properly align the first layer 108 and the second layer 110 with an offset of half a pitch of the first arrangement 112 of capacitive nodes, the first layer 108 and the second layer 110 may include fiducial marks, alignment sensors, or other alignment mechanisms.
[0031 ] For example, referring to FIG. 2A, the first layer 108 includes a first fiducial mark 200, while the second layer 110 includes a second fiducial mark 202. When the first fiducial mark 200, a cross in the present example, is aligned with the second fiducial mark 202, a target in the present example, the second arrangement 114 of capacitive nodes is offset from the first arrangement 1 12 of capacitive nodes by half the pitch of the first arrangement of capacitive nodes. The fiducial marks 200 and 202 may be used for example, by an operator to manually align the first layer 108 and the second layer 1 10, or to perform a quality assessment of the alignment between the first layer 108 and the second layer 110. In other examples, other shapes or patterns of fiducial marks may be utilized. Additionally, more than one fiducial mark may be used, for example in each of four comers of the first and second layers 108 and 1 10 to align the first and second layers 108 and 110.
[0032] According to another example, referring to FIG. 2B, the first layer 108 includes a first alignment sensor 210, while the second layer 110 includes a second alignment sensor 212. When the first alignment sensor 210 and the second alignment sensor 212 are aligned, the second arrangement 1 14 of capacitive nodes is offset from the first arrangement 112 of capacitive nodes by half the pitch of the first arrangement of capacitive nodes. [0033] For example, the first and second alignment sensors 210 and 212 may be capacitive nodes themselves, and hence may form a stacked capacitor 214. Accordingly, the controller 104 may measure an alignment capacitance of the stacked capacitor 214 to determine an alignment of the first and second alignment sensors 210 and 212. In particular, the measured alignment capacitance may be compared to a predefined target alignment capacitance; if the measured alignment capacitance is within a threshold tolerance of the target alignment capacitance, the alignment sensors 210 and 212 may be determined to be aligned, in other examples, an alternate controller (e.g., independent of the electronic device 100) may connect to and measure the alignment capacitance of the stacked capacitor 214. For example, in FIG. 2B, the alignment sensors 210 and 212 are not aligned, and hence the measured alignment capacitance of the stacked capacitor 214 may be outside the threshold tolerance from the target alignment capacitance.
[0034] In some examples, more than one alignment sensor may be used, for example, in each of the four corners of the first and second layers 108 and 110, or in a triangular or other pattern in a designated region of the first and second layers 108 and 1 10. The alignment capacitance of each of the stacked capacitors formed from the alignment sensors may be used to align the first and second layers 108 and 1 10.
[0035] Turning now to FIG. 3, another example electronic device 300 is depicted. The electronic device 300 may be a laptop or notebook computer, a tablet, an electronic pen sensor, or the like. The electronic device 300 includes a display device 302, a controller 304, and a projected-capacitive touch sensor 306.
[0036] The display device 302 is similar to the display device 102 and is generally to display a representation of an input to the touch sensor 306. For example, the display device may be a LCD display, an LED display, an OLED display, or the like. [0037] The controller 304 is similar to the controller 104, and may include a central processing unit (CPU), a microcontroller, a microprocessor, a processing core, a field-programmable gate array (FPGA), a circuit, a microchip, a chipset, or similar device capable of executing machine-readable instructions. The controller 304 may cooperate with a memory to execute instructions. Memory may include a non-transitory machine-readable storage medium that may be may electronic, magnetic, optical, or other physical storage device that stores executable instructions. The machine-readable storage medium may include, for example, random access memory (RAM), read-only memory (ROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, a storage drive, an optical disc, and the like. The machine-readable storage medium may be encoded with executable instructions. The controller 104 may include appropriate signal line drivers for a projected-capacitive array, and may be configured with sigma-delta based analog-to-digltal converters.
[0038] The touch sensor 306 is similar to the touch sensor 106. In particular, the touch sensor 306 is a projected-capacitive touch sensor to detect inputs from a source such as a finger of a user, an electromagnetic pen, or other suitable sources which affect the capacitance of the touch sensor 306. The touch sensor 306 includes a first projected-capacitive layer 308 and a second projected-capacitive layer 310.
[0039] Each of the first layer 308 and the second layer 310 may function as a touch sensor itself, having suitable capacitive nodes in configurations to detect the location of an input on the respective layer. That is, the first layer 308 includes first capacitive nodes (e.g., arranged in a first arrangement, as in the first layer 108) to generate a first capacitance signal in response to an electromagnetic Input to the touch sensor 306. Similarly, the second layer 310 includes second capacitive nodes (e.g., arranged in a second arrangement, as in the second layer 110) to generate a second capacitance signal in response to the input to the touch sensor 306. [0040] The second layer 310 is overlaid on the first layer 308 and is spaced apart from the first layer 308 to define a gap therebetween. Further, the touch sensor 306 includes an electrically insulating spacer 312 disposed in the gap between the first layer 308 and the second layer 310 to space the first layer 308 apart from the second layer 310. For example, the spacer 312 may be a plastic or glass material. In some examples, the spacer 312 may be about an order of magnitude thicker than the first and second layers 308 and 310. For example, the first and second layers 308 and 310 may be about 100 pm in thickness (e.g., a PET film), while the spacer 312 may be about 1 mm in thickness.
[0041 ] In operation, when an electromagnetic input is received at the touch sensor 306, the capacitance of the capacitive nodes is altered. The first layer 308 may output a first capacitance signal representing the input as detected by the first layer 308. Similarly, the second layer 310 may output a second capacitance signal representing the input as detected by the second layer 310.
[0042] The controller 304 receives the first capacitance signals representing the input as detected by the first layer 308 and the second capacitance signals representing the input as detected by the second layer 310. In some examples, the controller 304 may apply sigma-delta sampling to the first capacitance signal and the second capacitance signal to reduce the noise extracted from the first and second capacitance signals, and hence increase the quality of the resulting signals. In particular, utilization of sigma-delta sampling may allow the first and second layers 308 and 310 to be spaced apart, while maintaining a sufficient quality of signal extracted from the first layer 308 (i.e., the layer at a greater distance from the input, and hence experiencing greater noise) to compute the location and the tilt of the input, as described below.
[0043] The controller 304 may then combine the first capacitance signal and the second capacitance signal to determine the location of the input on the touch sensor 306. Additionally, the controller 304 may compare the first capacitance signal and the second capacitance signal to determine a tilt of the electromagnetic input relative to the touch sensor 306. [0044] For example, referring to FIG. 4, the touch sensor 306 is depicted receiving an input from an electromagnetic pen 400. The pen 400 emits electromagnetic waves 402 along a ray 404 extending through the length of the pen 400. The electromagnetic waves 402 propagate from the ray 404 and interface with the first and second layers 308 and 310 of the touch sensor 306. Since the electromagnetic waves 402 propagate from the ray 404, they may generate the greatest change in capacitance along the ray 404. That is, the first layer 308 and the second layer 310 may detect different peaks of capacitance signals based on the direction of propagation of the ray 404 (i.e., based on the tilt of the pen 400). Accordingly, the first capacitance signal and the second capacitance signal may be compared and, in further consideration of the geometrical configuration (i.e., the height of the spacer 312 and/or the space defined between the first layer 308 and the second layer 310), used to determine the tilt of the pen 400. That is, the controller 304 may determine respective peaks from each of the first capacitance signal and the second capacitance signal and triangulate using the relative geometrical relationship between the first layer 308 and the second layer 310 to determine the tilt of the pen 400.
[0045] Additionally, the tilt of the pen 400 may affect the distribution of the capacitance signals detected by the first layer 308 and the second layer 310. Accordingly, the first and second capacitance signals may be combined and, in further consideration of the geometrical configuration and the determined tilt of the pen 400, used to determine a location of the electronic input relative to the touch sensor 306. Thus, both the location and tilt of the pen 400 may be determined based on signals detected by the touch sensor 306 itself, rather than using external sensors embedded, for example, in the pen 400.
[0046] The controller 304 may additionally, in some examples, apply a machine learning model to the first and second capacitance signals to determine the change and flux of the first and capacitance signals over time. In particular, the controller 304 may determine a motion (e.g., tilt, rotation) of the pen 400 on the touch sensor 306. [0047] After having determined the location of the input, the controller 304 may display a representation of the location of the input at the display device 302. For example, in a drawing application, the location of the input may be represented as a dot. In some examples, the controller 304 may additionally represent the locations of inputs over time as a line or stroke. In some examples, the motion of the input may inform the representation of the line or stroke to display at the display device 302. For example, the motion of the input may affect the stroke width, curvature, intensity, and the like.
[0048] FIG. 5 depicts another example electronic device 500 with overlaid projected-capacitive layers.
[0049] The electronic device 500 may be a laptop or notebook computer, a tablet, an electronic pen sensor, or the like. The electronic device 500 includes a display device 502, a controller 504, and a projected-capacitive touch sensor 506.
[0050] The display device 502 is similar to the display device 102 and is generally to display a representation of an input to the touch sensor 506. For example, the display device may be a LCD display, an LED display, an OLED display, or the like.
[0051 ] The controller 504 is similar to the controller 104, and may include a central processing unit (CPU), a microcontroller, a microprocessor, a processing core, a field-programmable gate array (FPGA), a circuit, a microchip, a chipset, or similar device capable of executing machine-readable instructions. The controller 504 may cooperate with a memory to execute instructions. Memory may include a non-transitory machine-readable storage medium that may be may electronic, magnetic, optical, or other physical storage device that stores executable instructions. The machine-readable storage medium may include, for example, random access memory (RAM), read-only memory (ROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, a storage drive, an optical disc, and the like. The machine-readable storage medium may be encoded with executable instructions. The controller 104 may include appropriate signal line drivers for a projected-capacitive array, and may be configured with sigma-delta based analog-to-digital converters.
[0052] The touch sensor 506 is a projected-capacitive touch sensor to detect inputs from a source such as a finger of a user, an electromagnetic pen, or other suitable sources which affect the capacitance of the touch sensor 506. The touch sensor 506 includes a sheet 508 having a first portion 510 supporting a first arrangement of capacitive nodes, a second portion 512 supporting a second arrangement of capacitive nodes, and a folding portion 514 between the first portion 510 and the second portion 512. The sheet 508 may be formed of PET having etched PEDOT electrodes to allow for the sheet 508 to be folded at the folding portion 514.
[0053] Each of the first portion and the second portion 512 may function as a touch sensor itself, having suitable arrangements of capacitive nodes to detect the location of an input on the respective portion. The first and second portions 510 and 512 are overlaid to increase an effective resolution of the touch sensor 506 as compared to the first arrangement on the first portion 510 or the second arrangement on the second portion 512. In particular, the sheet 508 folds at the folding portion 514 to overlay the second portion 512 on the first portion 510 such that the first arrangement of capacitive nodes is offset from the second arrangement of capacitive nodes.
[0054] For example, the first and second arrangements of capacitive nodes may be arrays connected in rows and columns and having substantially the same dimensions. The first and second arrangements of capacitive nodes may be offset by about half the pitch between the capacitive nodes. That is, when the sheet 508 is folded at the folding portion 514 to overlay the second portion 512 on the first portion 510, the capacitive nodes may be arranged similarly to the arrangement depicted in FIG. 1 D.
[0055] To detect the location of input, each of the first portion 510 and the second portion 512 may have drive electrodes and sense electrodes. Further, in some examples, the folding portion 514 may support electrical traces to couple the first arrangement of capacitive nodes to the second arrangement of capacitive nodes. For exampie, referring to FIG. 4, the sheet 508 is depicted in its flattened (i.e., not folded) state.
[0056] The sheet 508 includes a first arrangement 600 of capacitive nodes on the first portion 510 and a second arrangement 602 of capacitive nodes on the second portion 512. The folding portion 514 supports electrical traces 604 coupling the first arrangement 600 to the second arrangement 602. Thus, the drive lines and sense lines may extend from the second portion 512 across the folding portion 514 to the first portion 510. Accordingly, the drive lines may be supported on a first side of the sheet 508, and the sense lines may be disposed on a second side of the sheet 508, opposite the first side. The sheet 508 may then be folded at the folding portion 514. The sensor 506 may therefore involve fewer drive channels (i.e., since drive lines from the first arrangement 600 and the second arrangement 602 are driven on the same channel) and generate fewer sense channels, resulting in a reduction in the number of data channels to process by the controller 504.
[0057] As will be appreciated, the first portion 510 and the second portion 512 may be spaced apart to define a gap therebetween to avoid electrical contact between the respective electrodes of the first portion 510 and the second portion 512. in some examples, the touch sensor 506 may include an electrically insulating spacer disposed in the gap between the first portion 510 and the second portion 512.
[0058] In operation, when an input is received at the touch sensor 506, the capacitance of the capacitive nodes is altered. By alternating current driven through the drive electrodes, the sense electrodes may output a set of capacitance signals representing the input as detected by the first and second arrangements 600 and 602. In particular, corresponding rows of drive electrodes of the first arrangement 600 and the second arrangement 602 are driven simultaneously as they correspond to the same drive line (i.e., as coupled by the electrical traces 604 on the folding portion. Similarly, corresponding columns of sense electrodes of the first arrangement 600 and second arrangement 602 may detect similar signals at different electrodes along the sense line. In other words, the capacitance detected at the first portion 510 may correspond to a predefined portion (i.e., predefined capacitive nodes of the sense lines) of the capacitance signal detected by the sense electrodes. Similarly, the capacitance detected at the second portion 512 may correspond to another predefined portion (i.e., predefined capacitive nodes of the sense lines) of the capacitance signal detected by the touch sensor 506.
[0059] The controller 104 receives the set of capacitance signals representing the Input to the touch sensor 506. The controller 104 may then resolve the set of capacitance signals into a first capacitance signal representing the input to the touch sensor 506 as detected by the first arrangement 600 of capacitive nodes (i.e., on the first portion 510) and a second capacitance signal representing the input to the touch sensor 506 as detected by the second arrangement 602 of capacitive nodes (i.e., on the second portion 512).
[0060] In some examples, prior to determining the location of the input on the touch sensor 506, the controller 504 may apply sigma-delta sampling to the first capacitance signal and the second capacitance signal, or to the set of capacitance signals to reduce the noise extracted from the first and second capacitance signals, and hence increase the quality of the resulting signal.
[0061 ] The controller 504 may then combine the first capacitance signal and the second capacitance signal to determine the location of the input on the touch sensor 506. The controller 504 may, in some examples apply a machine learning model to the first and second capacitance signals to determine the change and flux of the first and capacitance signals over time. In particular, the controller 504 may determine a motion (e.g., tilt, rotation) of the input on the touch sensor 506.
[0062] After having determined the location of the input, the controller 504 may display a representation of the location of the input at the display device 502. For example, in a drawing application, the location of the input may be represented as a dot. In some examples, the controller 504 may additionally represent the locations of inputs over time as a line or stroke. In some examples, the motion of the input may inform the representation of the line or stroke to display at the display device 502. For example, the motion of the input may affect the stroke width, curvature, intensity, and the like.
[0063] As described above, an example electronic device includes a display device, a controller, and a touch sensor having overlaid projected-capacitive layers. Each layer generates a capacitance signal representing an input to the touch sensor as detected by the layer. The capacitance signals from the layers may be combined to determine the location of the input on the touch sensor. In particular, the layers may be offset, for example by half a pitch of the capacitance nodes on the layers, to increase an effective resolution of the touch sensor. The layers may additionally be spaced apart to define a gap therebetween. The capacitance signals from the layers may be compared to determine a tilt of the input, based on triangulation using the relative geometrical relationship of the layers. Additionally, the controller may apply sigma-delta sampling to improve noise filtering, and allowing the layers to be spaced apart for said tilt determination. In some examples, the layers may be supported on the same sheet, connected by a folding portion, with the capacitive nodes on each layer connected by electrical traces. Advantageously, the number of data channels to drive and to sense the capacitance signal may be reduced.
[0064] The scope of the claims should not be limited by the above examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

1 . An electronic device comprising: a display device; a touch sensor comprising: a first projected-capacitive layer comprising a first arrangement of capacitive nodes; and a second projected-capacitive layer comprising a second arrangement of capacitive nodes, wherein the second layer is overlaid on the first layer to offset the second arrangement of capacitive nodes from the first arrangement of capacitive nodes; and a controller connected to the touch sensor, the controller to: receive a first capacitance signal from the first arrangement of capacitive nodes representing an input to the touch sensor; receive a second capacitance signal from the second arrangement of capacitive nodes representing the input to the touch sensor; combine the first capacitance signal and the second capacitance signal to determine a location of the input on the touch sensor; and display the location of the input at the display device.
2. The electronic device of claim 1 , wherein the second arrangement of capacitive nodes is offset from the first arrangement of capacitive nodes by half a pitch of the first arrangement of capacitive nodes.
3. The electronic device of claim 2, wherein: the first layer further comprises a first fiducial mark; and the second layer further comprise a second fiducial mark; and wherein when the first fiducial mark and the second fiducial mark are aligned, the second arrangement of capacitive nodes is offset from the first arrangement of capacitive nodes by half the pitch of the first arrangement of capacitive nodes.
4. The electronic device of claim 2, wherein: the first layer further comprises a first alignment sensor; and the second layer further comprises a second alignment sensor; and wherein when the first alignment sensor and the second alignment sensor are aligned, the second arrangement of capacitive nodes is offset from the first arrangement of capacitive nodes by half the pitch of the first arrangement of capacitive nodes.
5. The electronic device of claim 4, wherein the controller is to measure an alignment capacitance of a stacked capacitor formed by the first alignment sensor and the second alignment sensor to determine an alignment of the first alignment sensor and the second alignment sensor.
6. The electronic device of claim 1 , wherein the controller is to apply sigma-delta sampling to the first capacitance signal and the second capacitance signal to determine the location of the input on the touch sensor.
7. An electronic device comprising: a display device; a projected-capacitive touch sensor comprising: a sheet having: a first portion supporting a first arrangement of capacitive nodes; a second portion supporting a second arrangement of capacitive nodes; and a folding portion between the first portion and the second portion; wherein the sheet is to fold at the folding portion to overlay the first portion with the second portion such that the first arrangement of capacitive nodes is offset from the second arrangement of capacitive nodes; and a controller connected to the touch sensor, the controller to: receive a set of capacitance signals from the first arrangement of capacitive nodes and the second arrangement of capacitive nodes, the set of capacitance signals representing an input to the touch sensor; determine a location of the input based on the set of capacitance signals; and display the location of the input at the display device.
8. The electronic device of claim 7, wherein the folding portion is to support electrical traces to couple the first arrangement of capacitive nodes to the second arrangement of capacitive nodes.
9. The electronic device of claim 8, wherein, to determine the location of the input, the controller is to: resolve the set of capacitance signals into a first capacitance signal representing the input to the touch sensor as detected by the first arrangement of capacitive nodes and a second capacitance signal representing the input to the touch sensor as detected by the second arrangement of capacitive nodes; and combine the first capacitance signal and the second capacitance signal to determine the location of the input to the touch sensor.
10. The electronic device of claim 7. further comprising an electrically insulating spacer disposed between the first portion and the second portion when the first portion and the second portion are overlaid, the spacer to space the first arrangement of capacitive nodes apart from the second arrangement of capacitive nodes.
11 . The electronic device of claim 7, wherein the controller is to apply sigmadelta sampling to the set of capacitance signals to determine the location of the input on the touch sensor.
12. The electronic device of claim 1 1 , wherein the controller is further to apply a machine learning model to the sigma-delta sampled set of capacitance signals to determine a motion of the input on the touch sensor.
13. An electronic device comprising: a display device; a touch sensor comprising: a first layer of first capacitive nodes to generate a first capacitance signal in response to an electromagnetic input to the touch sensor; and a second layer of second capacitive nodes to generate a second capacitance signal in response to the input to the touch sensor, the second layer overlaid on the first layer and defining a gap therebetween; and a controller connected to the touch sensor, the controller to: combine the first capacitance signal and the second capacitance signal to determine a location of the electromagnetic input on the touch sensor; and compare the first capacitance signal and the second capacitance signal to determine a tilt of the electromagnetic input relative to the touch sensor.
14. The electronic device of claim 13, further comprising an electrically insulating spacer disposed between the first layer and the second layer to space the first layer apart from the second layer.
15. The electronic device of claim 13, wherein the first capacitance signal and the second capacitance signal are input into a machine learning model to determine a motion of the electromagnetic input on the touch sensor.
PCT/US2020/052926 2020-09-25 2020-09-25 Electronic devices with touch sensors having overlaid projected-capacitive layers WO2022066173A1 (en)

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Citations (4)

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Publication number Priority date Publication date Assignee Title
US20120113014A1 (en) * 2010-11-04 2012-05-10 Qrg Limited Touch position-sensing panel and method
US20130127772A1 (en) * 2011-11-22 2013-05-23 David Brent GUARD Touch Sensor with Conductive Lines having Different Widths
US20150372026A1 (en) * 2014-06-19 2015-12-24 Semiconductor Energy Laboratory Co., Ltd. Touch sensor, touch panel, touch panel module, and display device
US20180335892A1 (en) * 2017-05-16 2018-11-22 Honeywell International Inc. Devices and methods for using an infrared-projected capacitive (ir-pcap) touchscreen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120113014A1 (en) * 2010-11-04 2012-05-10 Qrg Limited Touch position-sensing panel and method
US20130127772A1 (en) * 2011-11-22 2013-05-23 David Brent GUARD Touch Sensor with Conductive Lines having Different Widths
US20150372026A1 (en) * 2014-06-19 2015-12-24 Semiconductor Energy Laboratory Co., Ltd. Touch sensor, touch panel, touch panel module, and display device
US20180335892A1 (en) * 2017-05-16 2018-11-22 Honeywell International Inc. Devices and methods for using an infrared-projected capacitive (ir-pcap) touchscreen

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