US 12,175,045 B2
Capacitance measurement circuit module
Masahiro Takata, Miyagi-ken (JP); and Hiroshi Shigetaka, Fukushima-ken (JP)
Assigned to Alps Alpine Co., Ltd., Tokyo (JP)
Filed by Alps Alpine Co., Ltd., Tokyo (JP)
Filed on Feb. 23, 2024, as Appl. No. 18/586,202.
Claims priority of application No. 2023-033932 (JP), filed on Mar. 6, 2023.
Prior Publication US 2024/0302924 A1, Sep. 12, 2024
Int. Cl. G06F 3/044 (2006.01)
CPC G06F 3/044 (2013.01) [G06F 2203/04107 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A circuit module for measuring capacitance, comprising:
a wiring board having a first surface and a second surface opposite to the first surface;
a sensor electrode disposed on the first surface of the wiring board and configured to detect a change in capacitance;
a sensor-side shield electrode disposed on the first surface and configured to shield the sensor electrode;
at least one board-side measurement terminal disposed on the second surface and connected to the sensor electrode via the wiring board;
a board-side shield terminal disposed on the second surface and connected to the sensor-side shield electrode via the wiring board;
a circuit-side shield electrode disposed on the second surface, adjacent to the board-side measurement terminal, and connected to the board-side shield terminal; and
a measurement integrated circuit (IC) provided on the second surface so as to overlap a portion of the circuit-side shield electrode in plan view from a direction normal to the second surface, the measurement IC including:
at least one circuit-side measurement terminal connected to the at least one board-side measurement terminal; and
a circuit-side shield terminal connected to the board-side shield terminal,
wherein the measurement IC is configured to measure capacitance of the sensor electrode, by outputting a measurement signal from the at least one circuit-side measurement terminal and a shield signal from the circuit-side shield terminal, the shield signal having a frequency and a phase which are the same as that of the measurement signal.