POSITIONAL TOUCH SENSOR WITH FORCE MEASUREMENT

• US 20130082970A1
• Filed: 06/08/2011
• Published: 04/04/2013
• Est. Priority Date: 06/11/2010
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Frey, Matthew H., Kieschke, Robert R., Weaver, Billy L.
• Granted Patent: US 9,904,393 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells
• CPC Class Codes: H01H 65/00 Apparatus or processes specially adapted to the manufacture of selector switches or parts thereof
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

A touch screen display sensor is provided that includes a transparent touch-sensing element disposed upon the surface of a transparent substrate and a force-sensing element disposed within the transparent touch-sensing element. The force-sensing element includes two sets of bands of micromesh and can include a pressure-responsive material between the bands of micromesh. The bands of micromesh include traces of a metallic conductor. The sets of bands of micromesh are spaced apart and occupy substantially parallel planes.

Claims

1. An article comprising:

an electronic display having a viewable region;

a transparent, insulating substrate having a surface; and

a force-sensing element comprising at least one micropattern of metallic traces disposed upon the surface of the substrate,

wherein the transparent insulating substrate is disposed upon the electronic display, and

wherein the force-sensing element overlays at least a portion of the viewable region of the electronic display without substantially obscuring the viewable region of the display.

2. An article according to claim 1, further comprising a transparent positional touch-sensing element.

3. An article according to claim 1, wherein the transparent insulating substrate comprises a polymer sheet or a glass sheet.

4. An article according to claim 3, wherein the polymer sheet comprises poly(methylmethacrylate), polycarbonate, or glass.

5. An article according to claim 1, wherein the metallic traces comprise silver, gold, palladium, platinum, copper, nickel, aluminum, molybdenum, or tungsten.

6. An article according to claim 1, wherein the force-sensing element comprises a lateral resistive strain gauge sensing element.

7. An article according to claim 1 wherein the force-sensing element has an open area fraction of at least 80 percent.

8. An article according to claim 1 wherein the metallic traces have a width between 0.5 micrometers and 20 micrometers.

9. A method of making a touch screen display according to claim 1, wherein the force-sensing element is fabricated by a process comprising:

disposing a metallic coating upon the surface of the substrate;

and

etching the metal to form a micropattern of conductive metal traces disposed upon the substrate.

10. A method of making a touch screen display according to claim 9, further comprising providing an inked stamp with raised features and contacting the raised features of the inked stamp to the metallic coating before etching the metal.

11. A method of making a touch screen display according to claim 10, wherein the inked stamp comprises a self-assembled monolayer-forming molecule.

12. An article comprising:

an electronic display having a viewable region;

a transparent, insulating substrate disposed upon at least a portion of the viewable region of the electronic display; and

a touch sensor disposed upon a surface of the substrate that overlays at least a portion of the viewable region of the electronic display;

wherein the touch sensor comprises a force-sensing element,

wherein the force-sensing element comprises a first set of bands of micromesh and a second set of bands of micromesh,

wherein the bands of micromesh each comprise traces of a metallic conductor,

wherein the first and second sets of bands of micromesh occupy substantially parallel planes that are spaced apart in the direction normal to the planes, and

wherein at least one band of the first set of bands of micromesh crosses over at least one band of the second set of bands of micromesh.

13. An article according to claim 12 further comprising a positional touch-sensing element that overlays at least a portion of the viewable region of the display without substantially obscuring the viewable region of the display.

14. An article according to claim 12, wherein the force-sensing element comprises a piezoresistive material, a piezoelectric material, or a capacitive force-sensing element.

15. An article according to claim 14, wherein the piezoresistive material comprises transparent conductive particles dispersed in a matrix.

16. An article according to claim 15, wherein the transparent conductive particles comprise indium tin oxide.

17. An article according to claim 14, wherein the piezoelectric material comprises a polymer.

18. An article according to claim 17, wherein the piezoelectric material comprises polyvinylidene fluoride or its derivatives.

19. An article according to claim 12, wherein the force-sensing element comprises a resistive strain gauge element.

20. An article according to claim 12, wherein the substantially parallel bands of micromesh comprise traces having a width of from about 0.5 micrometers to about 10 micrometers.

21. An article according to claim 12, wherein the micromesh of the force-sensing element has an open area fraction of at least 80 percent.

22. An article according to claim 12, wherein the first set of bands of micromesh is oriented such that the substantially parallel bands of micromesh are substantially orthogonal to the substantially parallel bands of micromesh in the second set of bands of micromesh.

23. An article according to claim 22, wherein each substantially parallel band of micromesh comprises an electrode.

24. An article according to claim 23, wherein the force-sensing element comprises one electrode from each set of parallel bands of micromesh, and wherein the force-sensing element is located where the bands cross.

25. A method of making a touch screen display according to claim 12, wherein the force-sensing element is fabricated by a process comprising:

disposing a metallic coating upon the surface of the substrate;

and

etching the metal to form a micropattern of conductive metal traces disposed upon the substrate.

26. A method of making a touch screen display according to claim 25, further comprising providing an inked stamp with raised features and contacting the raised features of the inked stamp to the metal coating before etching the metal.

27. A method of making a touch screen display to claim 26 wherein the inked stamp comprises a self-assembled monolayer-forming molecule.