FORCE-SENSING TOUCH SCREEN INPUT DEVICE

• US 20170102809A1
• Filed: 11/26/2015
• Published: 04/13/2017
• Est. Priority Date: 10/11/2015
• Status: Active Grant

• Current Assignee: Pressure Profile Systems Inc. (PPS U.K. Limited), Wisetouch Co, Ltd
• Original Assignee: Pressure Profile Systems Inc. (PPS U.K. Limited), Wisetouch Co, Ltd
• Inventors: Han, Sang Youl, Son, Jae S.
• Granted Patent: US 9,921,679 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 2203/04102 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
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A force sensing touch screen input device is a solid assembly of multiple layers including a display with a touch-sensitive external surface, a first and second electrode layers separated by a compressible dielectric structure—forming a capacitive force-sensing array, and a rigid planar substrate. One or both electrode layers may be formed by metallizing a polymer surface of the rigid substrate or by creating a conductive electrode onto an internal surface of the display. To increase reliability, each layer is permanently adhered to or formed onto an adjacent layer over its entire surface, whereby preventing internal shifts therebetween. To increase response time, the cover glass flexibility, compressible dielectric structure and the gasket structure between the cover glass and the rigid planar substrates are selected to provide elastic compression and recovery during normal operating conditions.

Claims

1. A force-sensing touch screen input device comprising:

a display with a touch-sensitive external surface protected by a cover glass facing outwards and an opposite internal surface facing inwards, said display is configured to allow detection of a location of touch of said touch-sensitive external surface by an external object,

a rigid substrate comprising a planar bottom portion and a raised peripheral portion surrounding thereof, said peripheral portion further comprising a ledge evenly spaced apart from said planar bottom portion and configured to support said display with said cover glass through a compressible gasket, and

a capacitance force sensor array positioned between said display and said planar bottom portion, said capacitance force sensor array comprising;

a first electrode layer having at least one first electrode, said first electrode layer is attached to, adhered to or formed onto said internal surface of said display,

a second electrode layer having at least one second electrode, said second electrode layer is attached to, adhered to or formed onto said planar bottom portion of said rigid substrate, and

a compressible dielectric structure attached to or adhered to both said first electrode layer and said second electrode layer so as to retain said first electrode layer and said second electrode layer together with a predefined gap therebetween, said compressible dielectric structure is formed with a plurality of voids throughout thereof,

whereby said display and said capacitance force sensor array are retained within said rigid substrate without additional fasteners, and

wherein touching said touch-sensitive surface of said display through said cover glass by said external object causing at least one of an inward prolapse of said display or a movement thereof towards said planar bottom portion of the rigid substrate, causing in turn compression of said compressible dielectric layer and a change in capacitance between said first electrode layer and said second electrode layer, thereby allowing to measure said force of touch using said change in capacitance.

2. The input device as in claim 1, wherein said compressible dielectric structure is permanently attached to said first electrode layer and said second electrode layer, said compressible dielectric structure is distributed throughout said capacitance force sensor array.

3. The input device as in claim 1 wherein at least one of said cover glass or said display is made from glass configured to allow elastic inward deformation when depressed by said external object and recovery from such deformation when said external object is removed.

4. The input device as in claim 3, wherein said compressible gasket between said cover glass and said ledge of said rigid substrate is formed using an elastic compressible dielectric foam.

5. The input device as in claim 3, wherein said compressible gasket between said cover glass and said ledge of said rigid substrate is formed using a solid elastic material less than about 2 millimeters wide.

6. The input device as in claim 5, wherein said elastic solid material is compressible silicone.

7. The input device as in claim 1 further comprising a back cover attached to said rigid substrate and spaced apart from said planar bottom portion thereof so as to protect said planar bottom portion from any deformation thereof.

8. An electronic device comprising the input device as in claim 1 and further comprising a control circuitry operably connected to said display and configured to detect the location of touch by said external object of said touch-sensitive surface thereof, said control circuitry is further operably connected to said at least one first electrode and said at least one second electrode of said capacitance force sensor array, said control circuitry is further configured to detect the force of touch using a change in capacitance between said first electrode layer and said second electrode layer upon said touch of said display by said external object, whereby said portable electronic device is configured for detecting both the location of touch and the force of touch by said external object.

9. A force-sensing touch screen input device comprising a solid assembly of layers as follows:

a display with a touch-sensitive external surface and an opposite internal surface,

a first electrode layer,

a compressible dielectric structure,

a second electrode layer, and

a rigid planar substrate,

wherein each layer is permanently attached to, adhered to or formed onto an adjacent layer over the entire surface thereof, whereby preventing internal shifts therebetween.

10. The force-sensing touch screen input device as in claim 9 further comprising a cover glass attached to said external touch-sensitive surface of said display.

11. The force-sensitive touch screen input device as in claim 9, wherein electrodes of said first electrode layer or said second electrode layer are positioned throughout said input device allowing detecting distribution of changes in electrical capacitance caused by application of external forces throughout the touch-sensitive area of said device.

12. The input device as in claim 9, wherein said layers are attached to, adhered to or formed therewith over their entire respective surfaces.

13. The device as in claim 9, wherein said display is made from an alkali-aluminosilicate glass.

14. A capacitive force-sensing touch screen input device comprising:

a rigid planar substrate,

a touch-sensitive display protected by a cover glass and sealed against said rigid planar substrate via a compressible gasket, and

a capacitive force-sensing array positioned therebetween, said capacitive force-sensing array in turn comprising;

a first electrode layer,

a second electrode layer, and

a compressible dielectric structure separating thereof with a predetermined gap,

said input device further comprising a control circuitry operably connected to said first electrode layer and said second electrode layer, said control circuitry is configured to detect a change in capacitance therebetween upon application of an external force to said display causing a reduction in said predetermined gap as a result of an elastic deformation of said compressible dielectric structure as well as at least one elastic deformation of said compressible gasket or inward prolapse of said cover glass,

wherein upon removal of said external force said predetermined gap is restored.

15. A force-sensing touch screen input device comprising:

a display with a touch-sensitive external surface protected by a cover glass facing outwards and an opposite internal surface facing inwards, said display is configured to allow detection of a location of touch of said touch-sensitive external surface by an external object,

a rigid substrate made from a conductive material, said rigid substrate comprising a planar bottom portion and a raised peripheral portion surrounding thereof, said peripheral portion further comprising a ledge evenly spaced apart from said planar bottom portion and configured to support said display with said cover glass through a compressible gasket, and

a capacitance force sensor array formed between said display and said planar bottom portion, said capacitance force sensor array comprising;

a first electrode layer having at least one first electrode, said first electrode layer is attached to, adhered to or formed onto said internal surface of said display, and

a compressible dielectric structure attached to or adhered to both said first electrode layer and said conductive planar bottom portion of said rigid substrate acting as a second electrode layer so as to retain said first electrode layer and said planar bottom portion together with a predefined gap therebetween, said compressible dielectric structure is formed with a plurality of voids throughout thereof,

whereby said display and said capacitance force sensor array are retained within said rigid substrate without additional fasteners, and

wherein touching said touch-sensitive surface of said display through said cover glass by said external object causing at least one of an inward deformation of said display or a movement thereof towards said planar bottom portion of the rigid substrate, causing in turn compression of said compressible dielectric layer and a change in capacitance between said first electrode layer and said second electrode layer, thereby allowing to measure said force of touch using said change in capacitance.