TOUCH SCREEN SENSOR HAVING VARYING SHEET RESISTANCE

• US 20130038572A1
• Filed: 08/21/2012
• Published: 02/14/2013
• Est. Priority Date: 02/28/2008
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Frey, Matthew H., Robrecht, Michael J., Jambor, George F.
• Granted Patent: US 8,704,799 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: C23F 1/02 Local etching
• CPC Class Codes: C23F 1/14 Aqueous compositions
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G06F 2203/04108 Touchless 2D- 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 without distance measurement in the Z direction
• 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 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/044 by capacitive means
• 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
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A touch screen sensor includes a visible light transparent substrate and an electrically conductive micropattern disposed on or in the visible light transparent substrate. The micropattern includes a first region micropattern within a touch sensing area and a second region micropattern. The first region micropattern has a first sheet resistance value in a first direction, is visible light transparent, and has at least 90% open area. The second region micropattern has a second sheet resistance value in the first direction. The first sheet resistance value is different from the second sheet resistance value.

Claims

1. A touch screen sensor, comprising:

a visible light transparent substrate; and

an electrically conductive micropattern disposed on or in the visible light transparent substrate, the micropattern comprising an elongated transparent conductive bar with a long axis, the bar comprising a metallic mesh that is visible light transparent and that has at least 90% open area,

wherein the micropattern exhibits a periodic sheet resistance along the long axis.

2. The touch screen sensor of claim 1, wherein the transparent conductive bar includes a minimum in resistance per unit length along the long axis, and the periodic variation in resistance per unit length along the long axis is characterized by peaks in resistance per unit length that are at least two times the minimum in resistance per unit length.

3. The touch screen sensor of claim 1, wherein the transparent conductive bar includes a minimum in resistance per unit length along the long axis, and the periodic variation in resistance per unit length along the long axis is characterized by peaks in resistance per unit length that are at least ten times the minimum in resistance per unit length.

4. A touch screen sensor, comprising:

a visible light transparent substrate; and

an electrically conductive micropattern disposed on or in the visible light transparent substrate, the micropattern comprising a metallic mesh that is visible light transparent and that has at least 90% open area,

wherein the mesh comprises traces and a periodic series of breaks in the traces.

5. The touch screen sensor of claim 4, wherein the mesh has open area between 95 and 99.5%

6. The touch screen sensor of claim 4, wherein the mesh has open area between 99.25 and 99.75%.

7. The touch screen sensor of claim 4, wherein the traces have width between 0.5 and 25 micrometers.

8. The touch screen sensor of claim 4, wherein the traces have width between 0.5 and 3 micrometers.

9. The touch screen sensor of claim 4, wherein the mesh defines an elongated transparent conductive bar with a long axis and wherein the traces with breaks have a vector component in the direction of the long axis.

10. The touch screen sensor of claim 4, wherein the mesh defines an elongated transparent conductive bar with a long axis, the transparent conductive bar includes a minimum in resistance per unit length along the long axis, and the periodic variation in resistance per unit length along the long axis is characterized by peaks in resistance per unit length that are at least two times the minimum in resistance per unit length.

11. The touch screen sensor of claim 4, wherein the mesh defines an elongated transparent conductive bar with a long axis, the transparent conductive bar includes a minimum in resistance per unit length along the long axis, and the periodic variation in resistance per unit length along the long axis is characterized by peaks in resistance per unit length that are at least ten times the minimum in resistance per unit length.

12. A touch screen sensor, comprising:

a visible light transparent substrate;

an electrically conductive micropattern disposed on or in the visible light transparent substrate, the micropattern comprising a first region micropattern within a touch sensing area and a second region micropattern, wherein each of the first region micropattern and the second region micropattern comprise metal traces having a uniform thickness and composition;

the first region micropattern comprising a first mesh having a first sheet resistance value in a first direction, being visible light transparent, and having at least 90% open area; and

the second region micropattern comprising a second mesh different from the first mesh, and having a second sheet resistance value in the first direction.

13. The touch screen sensor of claim 12, wherein, the sheet resistance varies continuously from the first region to the second region.

14. The touch screen sensor of claim 12, wherein the visible light transparent substrate comprises glass.

15. The touch screen sensor of claim 12, wherein the first sheet resistance is different from the second sheet resistance by a factor of between 1.25 and 100.

16. The touch screen sensor of claim 12, wherein the first sheet resistance value is different from the second sheet resistance value by a factor of between 1.25 and 10.

17. The touch screen sensor of claim 12, wherein the first sheet resistance value is different from the second sheet resistance value by a factor of between 2 and 5.

18. The touch screen sensor of claim 12, further comprising an electrical coupling to a touch sensor drive device for mutual capacitance measurements of the sensor.

19. The touch screen sensor of claim 12, wherein the second region micropattern further includes a resistor element that does not lie within the touch sensing area.

20. The touch screen sensor of claim 12, wherein the first mesh of the first region and the second mesh of the second region have different current-carrying cross-sectional area.

21. The touch screen sensor of claim 12, wherein the first mesh of the first region and the second mesh of the second region have different pitch.

22. The touch screen sensor of claim 12, wherein at least one of the first mesh and the second mesh includes selective breaks for modulating sheet resistance.