TOUCH SENSOR WITH INTEGRATED SIGNAL BUS EXTENSIONS
A touch sensor may be formed from a flexible substrate such as a sheet of polymer. The flexible substrate may have a main rectangular portion and a protruding portion. Capacitive touch sensor electrodes may be formed on the upper and lower surfaces of the flexible substrate. Signal lines may be coupled to the touch sensor electrodes. The ends of the signal lines may extend onto the protruding portion. Signal lines may be formed on upper and lower surfaces of the flexible substrate. The signal lines may be coupled to circuitry on a printed circuit using a connector that receives the end of the protruding portion. Ground structures on the protruding portion may be configured to overlap the signal lines or may be laterally interposed between upper surface signal lines and lower surface signal lines.
This application is a continuation application of U.S. patent application Ser. No. 13/363,648, filed Feb. 1, 2012 (U.S. Patent Application Publication No. 2013/0194759), the contents of which are incorporated by reference herein in their entirety for all purposes.
BACKGROUNDThis relates generally to sensors, and more particularly, to touch sensors for electronic devices.
Electronic devices such as portable computers and cellular telephones are often provided with displays. Touch sensitive displays are often used to provide users with the ability to interact with a display through touch-based commands. Touch sensitive displays can be implemented using capacitive touch sensor. Capacitive touch sensors may also be used in forming computer track pads and other input devices.
A capacitive touch sensor may include an array of touch sensor electrodes. In configurations such as those in which the touch sensor is being used as part of a display, the touch sensor electrodes may be formed from pads of transparent conductive material such as indium tin oxide. When a user brings a finger or other external object into the vicinity of the touch sensor electrodes, touch sensor circuitry can detect changes in capacitance on the touch sensor electrodes. These detected capacitance changes can be processed to generate touch event data for controlling an electronic device.
To satisfy consumer demand for small form factor devices, capacitive touch sensor arrays are sometimes formed on thin flexible substrates such as sheets of polyimide. A flexible printed circuit signal bus formed from a separate strip of polyimide can be attached to the edge of touch sensor substrate to route signals from the touch sensor to a logic board within a device.
The signal lines in the flexible printed circuit bus may be attached to the capacitive touch sensor substrate using anisotropic conductive film. Care must be taken not to impose excessive stress on anisotropic conductive film bonds between the flexible printed circuit bus and the touch sensor substrate, because excessive stress may lead to reliability issues. This type of restriction on the amount of acceptable stress for the anisotropic conductive film bonds may impose undesired constraints on use of the flexible printed circuit bus when installing a touch sensor in an electronic device. For example, the acceptable bend radius for the flexible printed circuit bus may be limited. There may also be additional cost and complexity associated with attaching the flexible printed circuit bus to the touch sensor.
It would therefore be desirable to be able to provide improved touch sensors for electronic devices.
SUMMARYAn electronic device may have a display mounted in a housing. A touch sensor may be mounted over the display or may be mounted in other portions of the device.
The touch sensor may be formed from a flexible substrate such as a sheet of polymer. The flexible substrate may have a main rectangular portion and a protruding portion that protrudes from one or more edges of the main rectangular portion.
Capacitive touch sensor electrodes and associated signal lines may be formed on the upper and lower surfaces of the flexible substrate. The signal lines may be coupled to the touch sensor electrodes. The signal lines may extend onto the protruding portion of the flexible substrate. The signal lines on the protruding portion of the flexible substrate may be coupled to circuitry on a printed circuit using one or more connectors.
Ground structures on the protruding portion may be configured to overlap the signal lines or may be laterally interposed between upper surface signal lines and lower surface signal lines.
Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.
Electronic devices such as electronic device 10 of
As shown in
A display such as display 20 may be mounted in housing 14. Display 20 may be a liquid crystal display, an organic light-emitting diode display, a plasma display, an electrowetting display, an electrophoretic display, or a display formed using other display technologies. Display 20 may be formed from one or more rigid substrate layers (e.g., one or more glass substrate layers) and/or one or more flexible substrate layers (e.g., one or more polymer layers).
Display cover layer 16 may cover display 20. Display cover layer 16 may be formed from glass, plastic, or other transparent material. Touch sensor 12 may be mounted between display 20 and display cover layer 16 using a layer of adhesive such as adhesive 18. If desired, touch sensor 12 may be mounted in housing 12 of device 10 using other arrangements. For example, touch sensor 12 may be attached to the upper surface of display structures 20 or may be incorporated into the layers of material that make up display structures 20. Touch sensors such as touch sensor 12 may also be incorporated into non-display components such as track pads or other input devices.
The touch sensor elements that form touch sensor 12 may be based on any suitable touch sensor technology such as acoustic touch technology, force-sensor-based touch technology, resistive touch technology, or capacitive touch technology (as examples). In capacitive touch sensors, capacitive electrodes may be formed from a conductive material. For example, for use in display applications in which the touch sensor electrodes are transparent to allow a user to view an underlying display, the touch sensor electrodes may be formed from a transparent conductive material such as indium tin oxide. Configurations in which touch sensor 12 is a capacitive touch sensor and in which touch sensor electrodes for touch sensor 12 are formed from transparent conductive materials are sometimes described herein as an example. Other types of arrangements may be used for touch sensor 12 if desired (e.g., arrangements with non-capacitive sensors, arrangements with capacitive electrodes formed from materials other than indium tin oxide, etc.).
The capacitive electrodes of touch sensor 12 may be formed on a substrate such as a transparent substrate. For example, the touch sensor electrodes may be formed on a rectangular clear flexible plastic substrate such as a sheet of polyimide or other polymer. As shown in
One or more electronic components such as components 24 may be mounted in housing 14 of device 10. Components 24 may include integrated circuits, discrete components such as capacitors, resistors, and inductors, switches, speakers, microphones, connectors, and other electrical components. Components 24 may be mounted on one or more printed circuit boards such as printed circuit 22. Printed circuit 22 may be, for example, a rigid printed circuit board such as a board formed from fiberglass-filled epoxy (e.g., FR4) or may be a flexible printed circuit (“flex circuit”) formed from a flexible sheet of polyimide or other flexible polymer. Components 24 may include surface mount technology (SMT) parts and other components that are mounted on printed circuit 22 using solder (as an example). The circuits that are mounted on printed circuit 22 may include, for example, one or more integrated circuits for controlling the operation of touch sensor 12. As an example, components 24 may include a touch sensor integrated circuit that converts raw capacitance data from touch sensor electrodes on touch sensor 12 into touch event data for processing by applications and operating system functions running on device 10.
Protruding flexible tail portion 26 of the touch sensor substrate may include conductive lines (e.g., metal traces) that form a signal bus. The signal bus may be used to conveying signals between touch sensor electrodes that are located on the main portion of touch sensor 12 that is located under cover layer 16 and components 24 on printed circuit 22. As shown in
Tail portion 26 of touch sensor 12 may be formed from one or more extending (protruding) portions of the substrate used to form touch sensor 12. An illustrative configuration is shown in
Capacitive electrodes such as electrodes 34 and 38 may be formed on substrate 32. Electrodes 34 and 38 may have any suitable shapes (e.g., squares, diamonds, elongated rectangles, etc.). In the illustrative configuration of
Conductive lines such as conductive lines 40 may each be coupled to a respective one of electrodes 34 and may be routed from main portion 33 (e.g., a rectangular planar portion) of substrate 32 to protruding portion 26. Conductive lines 42 may each be coupled to a respective one of electrodes 38 and may likewise be routed from main portion 33 to protruding portion 26. In protruding portion 26, signal lines such as lines 40 and 42 may run parallel to each other and may form signal buses (i.e., protruding portion 26 may form an integral flexible printed circuit bus for touch sensor 12).
Conductive electrodes 38 and 34 may, if desired, be formed on the same side of substrate 32. In this type of arrangement, an intervening dielectric coating layer may be used to prevent electrodes 38 and 34 from being shorted to each other. In the illustrative configuration of
Conductive lines 40 and 42 may be formed from conductive material such as metal (e.g., copper), transparent conductive material such as indium tin oxide, or other conductive substances. For example, conductive lines 40 and 42 may be copper lines, indium tin oxide lines, or lines that include a lower layer of indium tin oxide and an upper layer of copper (as examples).
Main portion 33 of substrate 32 may have a rectangular shape, a shape with curved edges, a shape with straight edges, a shape with curved and straight edges, or other suitable shapes. When mounted to a planar support structure such as planar cover glass 16 or planar display structures 20, main portion 33 may be maintained in a planar state. If desired, main portion 33 may be mounted to a curved surface (e.g., a curved cover glass, etc.).
Protruding structure 26 may extend from one or more edges of main portion 33. For example, protruding structure 26 may have three separate tab-shaped (e.g., rectangular) extending portions that each extend from the lower edge of main portion 33, as shown in
In the example of
As shown in
A cross-sectional side view of section T of extending portion 26 of substrate 32 of
A cross-sectional side view of section B of extending portion 26 of substrate 32 of
As shown in the top view of touch sensor 12 in
Grounding structures may be provided on substrate 32 such as ground structures 62 and 60. In the illustrative configuration of
The signal lines on extending portion 26 may be coupled to circuitry on a printed circuit such as printed circuit 22 of
As shown in
Connector 74 may have a connector housing such as connector housing 76. Metal structures such as metal spring structure 78 may be formed in housing 76 and may be used in interconnecting lines 42 to paths 72. As shown in
If desired, connector 74 may include multiple metal structures such as metal structures 78A and 78B of
One or more sections of extended portion 26 of touch sensor substrate 32 may be connected to printed circuit 22 using connectors such as connector 74 of
Protruding portion 26 of substrate 32 may be formed along any suitable edge of main portion 33 of substrate 32. In the example of
By arranging sections of protruding portion 26 on each of the edges of substrate 32 as shown in
In the example of
The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.
Claims
1. A touch sensor panel, comprising:
- a flexible substrate including a main portion having a main width and a plurality of capacitive touch sensor electrodes coupled to a plurality of signal lines disposed thereon; and
- one or more extending portions extending from a common edge of the main portion, each of the extending portions having an extending portion width narrower than the main width;
- wherein the one or more extending portions include first and second sections, each of the first and second sections having one or more of the plurality of signal lines formed on only one side of the extending portion and not on the other side of the extending portion.
2. The touch sensor panel of claim 1, wherein the flexible substrate comprises a flexible sheet of polymer, and wherein the main portion comprises a rectangular main portion having four edges, one of the four edges being the common edge.
3. The touch sensor panel of claim 1, wherein some of the plurality of capacitive touch sensor electrodes are formed on a first surface of the flexible substrate, and wherein some of the plurality of capacitive touch sensor electrodes are formed on a second surface of the flexible substrate.
4. The touch sensor panel of claim 3, wherein the first section includes a first ground structure on the second surface that at least partially overlaps at least one of the plurality of signal lines on the first surface, and wherein the second section includes a second ground structure on the first surface that at least partially overlaps at least one of the plurality of signal lines on the second surface.
5. The touch sensor panel of claim 3, wherein the plurality of capacitive touch sensor electrodes comprise indium tin oxide and wherein the plurality of signal lines comprise a conductive material selected from the group consisting of metal and indium tin oxide.
6. The touch sensor panel of claim 3, wherein the one or more extending portions further includes a third section that includes one or more of the plurality of signal lines on the first surface and a ground structure on the second surface that overlaps at least some of the plurality of signal lines on the first surface.
7. An electronic device, comprising:
- a housing;
- a display mounted in the housing; and
- a touch sensor panel that at least partially overlaps the display, wherein the touch sensor panel includes a flexible substrate having a main portion including a common edge with a main width and a plurality of separated extending portions extending from the common edge and having one or more extending portion widths less than the main width, and a plurality of signal lines formed on opposing first and second surfaces of the main portion and the plurality of separated extending portions;
- wherein a first extending portion of the plurality of separated extending portions includes one or more of the plurality of signal lines formed only on the first surface and not on the second surface, and wherein a second extending portion of the plurality of separated extending portions includes one or more of the plurality of signal lines formed only on the second surface and not on the first surface.
8. The electronic device of claim 7, wherein at least one of the separated extending portions is bent.
9. The electronic device of claim 7, wherein the touch sensor panel comprises a plurality of capacitive touch sensor electrodes on the flexible substrate and wherein the plurality of signal lines are coupled to the plurality of capacitive touch sensor electrodes.
10. The electronic device of claim 7, wherein the touch sensor panel further comprises a ground structure on the second surface that at least partially overlaps the one or more signal lines on the first surface.
11. The electronic device of claim 7, wherein the one or more of the plurality of signal lines formed only on the first surface are laterally offset from the one or more of the plurality of signal lines formed only on the second surface, and wherein the touch sensor panel further comprises:
- first ground structures on the second surface of the first extending portion that at least partially overlap the one or more of the plurality of signal lines formed only on the first surface; and
- second ground structures on the first surface of the second extending portion that at least partially overlap the one or more of the plurality of signal lines formed only on the second surface.
12. The electronic device of claim 7, wherein the first and second extending portions overlap each other in an overlapping region and wherein the touch sensor panel further comprises:
- first ground structures on the second surface of the first extending portion in the overlapping region, wherein the first ground structures are laterally interposed between the one or more of the plurality of signal lines;
- second ground structures on the first surface of the second extending portion in the overlapping region, wherein the second ground structures are laterally interposed between the one or more of the plurality of signal lines.
13. The electronic device of claim 9, further comprising:
- a printed circuit;
- at least one integrated circuit mounted on the printed circuit; and
- a connector on the printed circuit that receives at least one of the plurality of separated extending portions and has metal structures coupled to one or more of the plurality of signal lines.
14. A touch sensor panel comprising:
- a flexible polymer sheet having opposing first and second surfaces, wherein the flexible polymer sheet includes a main portion having a common edge with a main width and one or more protruding portions having one or more protruding portion widths less than the main width, the one or more protruding portions protruding from the common edge;
- capacitive touch sensor electrodes formed on the flexible polymer sheet; and
- a plurality of signal lines connected to the capacitive touch sensor electrodes and extending onto the one or more protruding portions;
- wherein the one or more protruding portions include first and second sections, the first section including one or more of the plurality of signal lines formed only on the first surface and not on the second surface, and the second section including one or more of the plurality of signal lines formed only on the second surface and not on the first surface; and
- wherein the first and second signal lines are non-overlapping.
15. The touch sensor panel of claim 14 wherein the main portion is rectangular and has four edges including the common edge.
16. The touch sensor panel of claim 14, wherein some of the capacitive touch sensor electrodes are formed on the first surface and some of the capacitive touch sensor electrodes are formed on the second surface, wherein some of the plurality of signal lines are coupled to the capacitive touch sensor electrodes on the first surface and some of the plurality of signal lines are coupled to the capacitive touch sensor electrodes on the second surface.
Type: Application
Filed: Jun 29, 2015
Publication Date: Nov 5, 2015
Inventors: Sunggu KANG (San Jose, CA), John Z. Zhong (Saratoga, CA)
Application Number: 14/754,623