Capacitance touch screen

• US 8,624,845 B2
• Filed: 09/26/2008
• Issued: 01/07/2014
• Est. Priority Date: 09/26/2008
• Status: Active Grant

• Current Assignee: Wistron Corporation
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Grivna, Edward L.
• Primary Examiner(s): Beck, Alexander S
• Assistant Examiner(s): HERMANN, KIRK W
• Application Number:
  US12/239,610
• Publication Number:
  US 20100079384A1
• Time in Patent Office: 1,929 Days
• Field of Search: 345/173
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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

Abstract

A touch screen is described. The touch screen is configured to have an array of conductive, optically transmissive sensor elements coupled to sensor circuitry. The sensor elements are disposed over a display to have a single layer of conductive, optically transmissive material positioned over pixels of the display.

Claims

1. A touch screen, comprising:

a display comprising a plurality of pixels, each pixel comprising a light-emitting portion and a non-light-emitting portion;

a sensor array coupled to sensor circuitry, the sensor array disposed over the display such that a single layer of conductive, optically transmissive material is positioned over substantially all of the plurality of pixels of the display, wherein the sensor array comprises a plurality of sensor elements disposed over the plurality of pixels and a plurality of electrical interconnects configured to couple at least two of the plurality of sensor elements together, each of the plurality of electrical interconnects extending between adjacent sensor elements of the plurality of sensor elements such that each interconnect extends between two pixels located diagonally from each other and within a non-light-emitting portion of a pixel in the plurality of pixels,

wherein substantially all the sensor elements are coupled together to form at least two axes including a row axis and a column axis,

the sensor element row axis is non-parallel with a pixel row axis of the display,

the sensor element column axis is non-parallel with a pixel column axis of the display, and

wherein a space between an edge of a first sensor element, in a first dimension of the array, adjacent to an edge of a second sensor element, in a second dimension of the array, has a width less than or equal to a pixel-mask width of the display; and

a first electrical interconnect between the first sensor element and a third sensor element, in the first dimension of the array, wherein the first and third sensor elements and first electrical interconnect comprise a same layer of optically transmissive conductive material.

2. The touch screen of claim 1, wherein the number of sensor elements in a row differs between the rows.

3. The touch screen as in claim 1, wherein the sensor elements have dimensions that are a multiple of the pixel-pitch of the display.

4. The touch screen as in claim 1, wherein the sensor array is of a same layer of optically transmissive conductive material comprising at least one of:

ITO, PEDOT, conductive ink, and graphite.

5. The touch screen as in claim 1, wherein the first sensor element edge is parallel to a sub-pixel border of the display.

6. The touch screen as in claim 1, further comprising a second electrical interconnect between the second sensor element and a fourth sensor element, in the second dimension of the array, wherein the second electrical interconnect comprises an optically opaque material.

7. A touch screen substrate, comprising:

an array of pixels, each pixel comprising a light-emitting portion and a non-light-emitting portion;

an n-dimensional sensor array coupled to the pixels and including sensor elements and a plurality of electrical interconnects between sensor elements, wherein;

all of the sensor elements are coupled together to form at least two axes including a row axis and a column axis,

the number of sensor elements in a row differs between the rows,

all edges of the sensor elements are substantially parallel to edges of the pixels,

the row axis and the column axis are non-parallel to the edges of the pixels,

the row axis of the sensor elements is non-parallel with a pixel row axis of the display,

the column axis of the sensor elements is non-parallel with a pixel column axis of the display,

the number of sensor elements are disposed over the pixels, and each of the plurality of electrical interconnects extends between adjacent sensor elements such that each interconnect extends between two pixels located diagonally from each other and within a non-light-emitting portion of a pixel in the array of pixels,

wherein a space between an edge of a first sensor element, in a first dimension of the array, adjacent to an edge of a second sensor element, in a second dimension of the array, has a width less than or equal to a pixel-mask width of the display; and

a first electrical interconnect between the first sensor element and a third sensor element, in the first dimension of the array, wherein the first and third sensor elements and first electrical interconnect comprise a same layer of optically transmissive conductive material.

8. The touch screen substrate as in claim 7, wherein the number of sensor elements in a column differs between the columns.

9. The touch screen substrate as in claim 7, wherein each sensor element comprises an optically transmissive conductive material patterned into a polygon, and wherein at least one side of the polygon is substantially parallel or perpendicular to a length of the substrate.

10. The touch screen substrate as in claim 9, wherein each of the sensor elements is a rectangle.

11. The touch screen substrate as in claim 7, wherein the sensor elements at the perimeter edge of the array are a polygon of the same number of sides as the sensor elements within the interior of the array.

12. The touch screen substrate as in claim 7, wherein the sensor elements in a first row of the array have a pitch greater than 1 mm and a first sensor element of the first row is spaced apart from a nearest neighboring sensor element by less than 25 μ

m.

13. The touch screen substrate as in claim 7, wherein all the sensor elements of the array are of a same layer of optically transmissive conductive material comprising at least one of ITO, PEDOT, conductive ink, and graphite and wherein the sensor elements within at least one of a row or a column are coupled together with an optically opaque conductive material.

14. A method for determining a location of a touch on a touch sensitive display screen having a plurality of pixels, each pixel comprising a light-emitting portion and a non-light-emitting portion, the method comprising:

receiving a coordinate of a capacitance sensor array representing a location of a sensed touch, wherein;

the capacitance sensor array comprises a plurality of sensor elements and a plurality of electrical interconnects,

the plurality of sensor elements disposed over the plurality of pixels and coupled together to form at least two axes including a row axis and a column axis and the row axis and the column axis are non-parallel to the edges of the pixels of the display screen,

the sensor element row axis is non-parallel with a pixel row axis of the display,

the sensor element column axis is nonparallel with a pixel column axis of the display,

each of the plurality of electrical interconnects extending between adjacent sensor elements of the plurality of sensor elements such that each interconnect extends between two pixels located diagonally from each other and within a non-light-emitting portion of a pixel of the plurality of pixels of the display screen; and

determining a coordinate of the display screen corresponding to the sensed touch by performing a rotational transform of the received coordinate based on a relationship between the orientation of the display screen and the orientation of the capacitance sensor array.

15. The method as in claim 14, wherein the rotation transform is an angular math transform between a sensor array coordinate space and a display coordinate space.

16. The method as in claim 14, wherein the rotational transform is a transform between a sensor element row-column coordinate system of the sensor array and a pixel row-column coordinate system of the display.