Shield for a Capacitive Touch System
Touch sensor systems and methods are disclosed including a radio frequency antenna that can be placed on or very near the touch pad. The touch pad sensor includes a patterned shielding that shields the touch pad sensor from back-side signals and has opening that are large enough to allow radio frequencies to pass through the touch pad sensor.
1 . An apparatus, comprising:
a touch sensor;
a first antenna;
a shield structure positioned adjacent the touch sensor such that the shield structure shields portions of the touch sensor from the first antenna; and
at least one radio frequency transparent section incorporated into the shield;
wherein the radio frequency transparent section allows radio frequency to pass through the shield structure and the touch sensor.
2 . The apparatus of claim 1 , wherein the shield structure further includes a metal layer deposited on an electrically insulating material, and the radio frequency transparent section includes an opening defined in the metal layer that allows radio frequency to pass through a center of a sensor cell of the touch sensor.
3 . The apparatus of claim 2 , wherein the touch sensor includes a mutual capacitance intersection between a first electrode and a second electrode; and the radio frequency transparent section is offset from the mutual capacitance intersection.
4 . The apparatus of claim 3 , wherein the metal layer shields the mutual capacitance intersection and electrodes of the touch sensor while allowing the radio frequency to pass through the openings between electrodes of the touch sensor.
5 . The apparatus of claim 4 , wherein the metal layer has an increased area that overlaps with the mutual capacitance intersection.
6 . The apparatus of claim 2 , wherein the touch sensor further includes first mutual capacitance intersection spaced away from the first antenna at a first distance and a second mutual capacitance intersection spaced away from the first antenna at a second distance where the second distance is farther away from the first antenna than the first distance;
wherein a first metal layer area of the shield structure overlapping with the first mutual capacitance intersection is smaller than a second metal layer area of the shield structure overlapping with the second mutual capacitance intersection.
7 . The apparatus of claim 1 , wherein the shield structure further includes a metal layer deposited on an electrically insulating material, and the radio frequency transparent section includes multiple shield openings defined in the metal layer.
8 . The apparatus of claim 7 , wherein at least some of the multiple openings become progressively smaller as the distance from the first antenna increases.
9 . The apparatus of claim 7 , wherein the shield structure includes a first region with a first subset of shield openings having a first size and a second region with a second subset of shield openings having a second region having a second size, wherein the first region is closer to the first antenna than the second region, and wherein the first size is larger than the second size.
10 . The apparatus of claim 1 , further comprising:
a second antenna;
a second radio frequency transparent section incorporated into the shield structure that is sized based at least in part on a proximity to the second antenna; and
wherein the first radio frequency transparent section is sized based at least in part on a proximity to the first antenna.
11 . An apparatus, comprising:
a touch sensor;
an antenna;
a shield structure positioned near the touch sensor and the antenna; and
patterned shielding areas incorporated into the shield structure;
wherein the patterned shielding areas include radio frequency transparent sections that allow radio frequency from the antenna to pass through the shield structure and the touch sensor.
12 . The apparatus of claim 11 , wherein the patterned shielding areas are separated by openings defined in electrically conductive material.
13 . The apparatus of claim 11 , wherein the patterned shielding areas are positioned to shield mutual capacitance junctions of the touch sensor while leaving a center of at least some touch sensor cells open to allow radio frequency to pass through the center of the least some touch sensor cells.
14 . The apparatus of claim 13 , wherein the patterned shielding areas are positioned to shield individual sensor junctions.
15 . The apparatus of claim 11 , wherein the antenna is configured to transmit a WiFi signal.
16 . The apparatus of claim 11 , wherein the patterned shielding areas are connected radially.
17 . The apparatus of claim 11 , wherein the patterned shielding areas are configured to minimize an induced current from a near field communication antenna and reduce the power of a near field communication system.
18 . An apparatus, comprising:
a touch sensor;
an antenna;
a shield structure positioned near the touch sensor and the antenna; and
multiple shield openings defined in an electrically conductive layer of the shield structure that are large enough to allow radio frequency from the antenna to pass through the shield structure and portions of the touch sensor.
19 . The apparatus of claim 18 , wherein the electrically conductive layer defines the shield openings with multiple vertical columns and multiple horizontal rows positioned to overlap with a grid of electrode in the touch sensor.
20 . The apparatus of claim 18 , wherein multiple shield openings are located in a first region of the touch sensor proximate to the antenna and the shield structure comprises a solid electrically conductive layer without shield openings in a second region of the touch sensor that is spaced farther away from the antenna than the first region.