Multipoint touchscreen

• US 20060097991A1
• Filed: 05/06/2004
• Published: 05/11/2006
• Est. Priority Date: 05/06/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Hotelling, Steve, Strickon, Joshua A., Huppi, Brian Q.
• Granted Patent: US 7,663,607 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A touch panel having a transparent capacitive sensing medium configured to detect multiple touches or near touches that occur at the same time and at distinct locations in the plane of the touch panel and to produce distinct signals representative of the location of the touches on the plane of the touch panel for each of the multiple touches is disclosed.

Claims

1. A touch panel having a transparent capacitive sensing medium configured to detect multiple touches or near touches that occur at the same time and at distinct locations in the plane of the touch panel and to produce distinct signals representative of the location of the touches on the plane of the touch panel for each of the multiple touches.

2. The touch panel as recited in claim 1 wherein the transparent sensing medium includes a pixilated array of transparent capacitance sensing nodes.

3. The touch panel as recited in claim 1 wherein the transparent capacitive sensing medium comprises:

a transparent electrode layer, the electrode layer including a plurality of electrically isolated electrodes and electrode traces formed from a transparent conductive material, each of the electrodes being placed at different locations in the plane of the touch panel, each of the electrodes having an individual trace for operatively coupling to capacitive monitoring circuitry.

4. The touch panel as recited in claim 3 further including one or more integrated circuits for monitoring the capacitance at each of the electrodes, the integrated circuits being operatively coupled to the electrodes via the traces.

5. The touch panel as recited in claim 3 wherein the electrodes are placed in rows and columns.

6. The touch panel as recited in claim 3 wherein the electrodes and traces are formed from indium tin oxide (ITO).

7. The touch panel as recited in claim 1 wherein the transparent capacitive sensing medium comprises:

a first layer having a plurality of transparent conductive lines that are electrically isolated from one another; and

a second layer spatially separated from the first layer and having a plurality of transparent conductive lines that are electrically isolated from one another, the second conductive lines being positioned transverse to the first conductive lines, the intersection of transverse lines being positioned at different locations in the plane of the touch panel, each of the conductive lines being operatively coupled to capacitive monitoring circuitry.

8. The touch panel as recited in claim 7 wherein the conductive lines on each of the layers are substantially parallel to one another.

9. The touch panel as recited in claim 8 wherein the conductive lines on different layers are substantially perpendicular to one another.

10. The touch panel as recited in claim 7 wherein the transparent conductive lines of the first layer are disposed on a first glass member, and wherein the transparent conductive lines of the second layer are disposed on a second glass member, the first glass member being disposed over the second glass member.

11. The touch panel as recited in claim 10 further including a third glass member disposed over the first glass member, the first and second glass members being attached to one another via an adhesive layer, the third glass member being attached to the first glass member via another adhesive layer.

12. The touch panel as recited in claim 7 wherein the conductive lines are formed from indium tin oxide (ITO).

13. A display arrangement comprising:

a display having a screen for displaying a graphical user interface;

a transparent touch panel allowing the screen to be viewed therethrough and capable of recognizing multiple touch events that occur at different locations on the touch sensitive surface of the touch screen at the same time and to output this information to a host device.

14. The display arrangement as recited in claim 13 wherein the touch screen includes a multipoint sensing arrangement configured to simultaneously detect and monitor touches and the magnitude of those touches at distinct points across the touch sensitive surface of the touch screen.

15. The display arrangement as recited in claim 14 wherein the multipoint sensing arrangement provides a plurality of transparent capacitive sensing nodes that work independent of one another and that represent different points on the touch screen.

16. The display arrangement as recited in claim 15 wherein the capacitive sensing nodes are formed with a transparent conductive medium.

17. The display arrangement as recited in claim 16 wherein the transparent conductive medium corresponds to indium tin oxide (ITO).

18. The display arrangement as recited in claim 16 wherein the capacitive sensing nodes are based on self capacitance.

19. The display arrangement as recited in claim 18 wherein the transparent conductive medium is patterned into electrically isolated electrodes and traces, each electrode representing a different coordinate in the plane of the touch screen, and the traces connecting the electrodes to a capacitive sensing circuit.

20. The display arrangement as recited in claim 16 wherein the capacitive sensing nodes are based on mutual capacitance.

21. The display arrangement as recited in claim 18 wherein the transparent conductive medium is patterned into a group of spatially separated lines formed on two different layers, driving lines are formed on a first layer and sensing lines are formed on a second layer, the sensing lines being configured to traverse across the driving lines in order to form a capacitive sensing node, the driving lines being connected to a voltage source and the sensing lines being connected to a capacitive sensing circuit, the voltage source driving a current through one driving line at a time and because of capacitive coupling, the current is carried through to the sensing lines at each of the capacitive sensing nodes.

22. The display arrangement as recited in claim 16 wherein the capacitive sensing nodes are coupled to a capacitive sensing circuit, and wherein the capacitive sensing circuit monitors changes in capacitance that occurs at each of the capacitive sensing nodes, the position where changes occur and the magnitude of those changes being used to help recognize the multiple touch events.

23. The display arrangement as recited in claim 22 wherein the capacitive sensing circuit comprises:

a multiplexer that receives signals from each of the capacitive sensing nodes at the same time, stores all the signals and sequentially releases the signals one at a time through an output channel;

an analog to digital converter operatively coupled to the MUX through the output channel, the analog to digital converter being configured to convert the incoming analog signals into outgoing digital signals;

a digital signal processor operatively coupled to the analog to digital converter, the DSP filtering noise events from the raw data, calculating the touch boundaries for each touch that occurs on the touch screen at the same time and thereafter determining the coordinates for each touch.

24. The display arrangement as recited in claim 13 wherein the touch panel comprises:

a glass member disposed over the screen of the display;

a transparent conductive layer disposed over the glass member, the conductive layer including a pixilated array of electrically isolated electrodes;

a transparent cover sheet disposed over the electrode layer; and

one or more sensor integrated circuits operatively coupled to the electrodes.

25. The display arrangement as recited in claim 13 wherein the touch panel comprises:

a first glass member disposed over the screen of the display;

a first transparent conductive layer disposed over the first glass member, the first transparent conductive layer comprising a plurality of spaced apart parallel lines having the same pitch and linewidths;

a second glass member disposed over the first transparent conductive layer;

a second transparent conductive layer disposed over the second glass member, the second transparent conductive layer comprising a plurality of spaced apart parallel lines having the same pitch and linewidths, the parallel lines of the second transparent conductive layer being substantially perpendicular to the parallel lines of the first transparent conductive layer;

a third glass member disposed over the second transparent conductive layer; and

one or more sensor integrated circuits operatively coupled to the lines.

26. The display arrangement as recited in claim 25 further including dummy features disposed in the space between the parallel lines, the dummy features optically improving the visual appearance of the touch screen by more closely matching the optical index of the lines.

27. A computer readable medium including at least computer code executable by a computer, the computer code comprising:

receiving multiple touches on the surface of a transparent touch screen at the same time;

separately recognizing each of the multiple touches; and

reporting touch data based on the recognized multiple touches.

28. A computer system comprising:

a processor configured to execute instructions and to carry out operations associated with the computer system;

a display device that is operatively coupled to the processor;

a touch screen that is operatively coupled to the processor, the touch screen being a substantially transparent panel that is positioned in front of the display, the touch screen being configured to track multiple objects, which rest on, tap on or move across the touch screen at the same time, the touch screen including a capacitive sensing device that is divided into several independent and spatially distinct sensing points that are positioned throughout the plane of the touch screen, each sensing point being capable of generating a signal at the same time, the touch screen also including a sensing circuit that acquires data from the sensing device and that supplies the acquired data to the processor.

29. A touch screen method comprising:

driving a plurality of sensing points;

reading the outputs from all the sensing lines connected to the sensing points;

producing and analyzing an image of the touch screen plane at one moment in time in order to determine where objects are touching the touch screen; and

comparing the current image to a past image in order to determine a change at the objects touching the touch screen.

30. A digital signal processing method, comprising:

receiving raw data, the raw data including values for each transparent capacitive sensing node of a touch screen;

filtering the raw data;

generating gradient data;

calculating the boundaries for touch regions base on the gradient data; and

calculating the coordinates for each touch region.

31. The method as recited in claim 30 wherein the boundaries are calculated using a watershed algorithm.