Touch sensitive display for a portable device

• US 20060209039A1
• Filed: 07/08/2004
• Published: 09/21/2006
• Est. Priority Date: 07/21/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Destura, Galileo June Adeva, Van Delden, Martinus Hermanus Wilhelmus Maria, Van Beek, Jozef Thomas Martinus, Huitema, Hjalmar Edzer Ayco, Kemmeren, Antonius Lucien Adrianus Maria
• Granted Patent: US 8,325,143 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 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04146 using pressure sensitive conductive elements delivering a boolean signal and located between crossing sensing lines, e.g. located between X and Y sensing line layers

Abstract

A portable device is provided having a touch sensitive display (100) comprising an active matrix display element (101) and a touch sensitive element (103). The touch sensitive element (103) is disposed on the viewer distal side of the active matrix display element (101) thereby not affecting the display properties. The touch sensitive element (103) comprises a first and second conductive layer (113, 115) each having a plurality of conductors. The conductive layers (113, 115) sandwich a pressure sensitive layer (117) which modifies an electrical conductivity between two conductors of the two conductive layers (113, 115) in response to a pressure point resulting from an applied pressure. Thus, accurate position detection is achieved. The conductors may be aligned with the active matrix and the requirement for calibration may be obviated.

Claims

1. A touch sensitive display (100) comprising

an active matrix display element (101) having a viewer proximal side and a viewer distal side;

and

a touch sensitive element (103) disposed on the viewer distal side of the active matrix display element (101) and comprising;

a first conductive layer (113) comprising a first plurality of conductors;

a second conductive layer (115) comprising a second plurality of conductors; and

a pressure sensitive layer (117) sandwiched between the first conductive layer (113) and the second conductive layer (115) and operable to modify an electrical conductivity between a first conductor of the first plurality of conductors and a second conductor of the second plurality of conductors in response to a pressure point resulting from an applied pressure.

2. A touch sensitive display as claimed in claim 1 wherein the touch sensitive element (103) comprises a plurality of pressure sensitive elements.

3. A touch sensitive display as claimed in claim 2 wherein the plurality of touch sensitive elements is formed by the first and second plurality of conductors.

4. A touch sensitive display as claimed in claim 2 wherein the plurality of pressure sensitive elements is aligned with pixels of the active matrix display element (101).

5. A touch sensitive display as claimed in claim 1 wherein the first plurality of conductors forms rows of a pressure sensitive array.

6. A touch sensitive display as claimed in claim 1 wherein the second plurality of conductors forms columns of a pressure sensitive array.

7. A touch sensitive display as claimed in claim 1 wherein the pressure sensitive layer (117) comprises a piezoelectric material operable to modify the electrical conductivity.

8. A touch sensitive display as claimed in claim 1 wherein the pressure sensitive layer (117) comprises Micro-ElectroMechanical (EM) switches operable to modify the electrical conductivity.

9. A touch sensitive display as claimed in claim 1 further comprising detection means operable to determine a position of the pressure point in response to the change in electrical conductivity between the first conductor and the second conductor.

10. A touch sensitive display as claimed in claim 9 wherein the detection means is operable to detect a plurality of simultaneous pressure points.

11. A touch sensitive display as claimed in claim 9 wherein the detection means comprise a signal source (309) for outputting a signal on the first conductor and a sense amplifier (311) coupled to the second conductor for detecting an electrical signal caused by an electrical conductivity being formed between the first conductor and the second conductor in response to the pressure point.

12. A touch sensitive display as claimed in claim 11 wherein the electrical signal is an electrical charge and the sense amplifier (311) is a charge sensitive amplifier.

13. A touch sensitive display as claimed in claim 11 further comprising a display controller having a buffer amplifier (309) operable to provide a display control signal and wherein the touch sensitive display is operable to couple a single amplifier (309) as the buffer amplifier (309) in a display driver configuration and as the signal source (309) in a pressure point detection configuration.

14. A touch sensitive display as claimed in claim 11 further comprising a display controller having a buffer amplifier (311) operable to provide a display control signal and wherein the touch sensitive display is operable to couple a single amplifier (311) as the buffer amplifier (311) in a display driver configuration and as the sense amplifier (311) in a pressure point detection configuration.

15. A portable device comprising a touch sensitive display as claimed in claim 1.