Patent ID: 9140737
Filing Date: 2015-09-22
Classification: G01D,G01R,G06F,H03K,Y10T

Abstract:
1. An apparatus comprising: a first layer comprising a first substrate, first capacitive sensors on the first substrate and first electrical leads on the first substrate extending from the first capacitive sensors towards side edges of the first substrate; and a second layer comprising a second substrate, second capacitive sensors on the second substrate and second electrical leads on the second substrate extending from the second capacitive sensors towards side edges of the second substrate, where the first layer is located on top of the second layer, where the first capacitive sensors are arranged in a substantially ring-shaped pattern, where the second capacitive sensors are arranged in a pattern sized to fit under the first layer within an inside perimeter of the substantially ring-shaped pattern of the first capacitive sensors, and where the second layer comprises electrically conductive material substantially spaced from the second capacitive sensors and the second electrical leads, where the electrically conductive material is located under the first capacitive sensors and the first electrical leads to form an electrical rear guard for the first capacitive sensors and the first electrical leads of the first layer, and the electrically conductive material is substantially not located on top of the second capacitive sensors and the second electrical leads of the second layer.