Electrostatic input device

Patent metadata

Field	Value
Publication number	US-2024264327-A1
Application number	US-202418421707-A
Country	US
Kind code	A1
Filing date	Jan 24, 2024
Priority date	Feb 6, 2023
Publication date	Aug 8, 2024
Grant date	—

Abstract

An electrostatic input device includes a first sensor electrode for input detection, an electronic part, a second sensor electrode for noise detection, the second sensor electrode being placed between the first sensor electrode and the electronic part, and a measurement circuit that measures the capacitance of the first sensor electrode and the capacitance of the second sensor electrode, the measurement circuit calculating the difference between the capacitance of the first sensor electrode and a value obtained by multiplying the capacitance of the second sensor electrode by a constant.

First claim

1 . An electrostatic input device comprising:
at least one first sensor electrode configured to detect an input operation; at least one electronic part; at least one second sensor electrode configured to detect a noise from the electronic part, the second sensor electrode being disposed placed between the first sensor electrode and the electronic part; and a measurement circuit configured to measure a capacitance of the first sensor electrode and a capacitance of the second sensor electrode, the measurement circuit calculating a difference between the capacitance of the first sensor electrode and a proportioned capacitance which is a value obtained by multiplying the capacitance of the second sensor electrode by a constant.

2 . The electrostatic input device according to claim 1 , wherein the at least one electronic part is a light-emitting diode.

3 . The electrostatic input device according to claim 2 , wherein the at Least one light-emitting diode is driven by a pulse width modulation driving signal.

4 . The electrostatic input device according to claim 2 , further comprising:
a multi-layer substrate having a first surface; and a plurality of mounting electrodes formed on the first surface, on which a plurality of the electronic parts are mounted wherein the at least one first sensor electrode, the at least one second sensor electrode, and the plurality of mounting electrodes are disposed on the first surface of the multi-layer substrate, such that the second sensor electrode surrounds the first sensor electrode in plan view from a direction normal to the first surface, and the plurality of electronic parts mounted on the plurality of mounting electrodes are disposed around the second sensor electrode in the plan view.

5 . The electrostatic input device according to claim 4 ,
wherein the first sensor electrode has a is circular shape, and the second sensor electrode has a circular ring shape around the first sensor electrode in the plan view, and wherein the plurality of electronic parts are arranged around the second sensor electrode at equal angular intervals viewed from a center of the first sensor electrode.

6 . The electrostatic input device according to claim 4 , further comprising:
a first shield electrode disposed on the first surface and enclosing each of the first sensor electrode, the second sensor electrode, and the plurality of mounting electrodes in the plan view, wherein the first sensor electrode, the second sensor electrode, and the first shield electrode are driven by signals each including an alternating-current component having a same frequency and a same phase.

7 . The electrostatic input device according to claim 6 , further comprising:
a driving integrated circuit disposed on a second surface of the multi-layer substrate opposite to the first surface and connected to the plurality of electronic parts through the multi-layer substrate, the driving integrated circuit being configured to drive the plurality of electronic parts; and a second shield electrode disposed in a first inner layer of the multi-layer substrate and connected to the first shield electrode through the multi-layer substrate, and wherein the second shield electrode is arranged such that the second shield electrode overlaps each of the first sensor electrode, the second sensor electrode, and the driving integrated circuit in the plan view.

8 . The electrostatic input device according to claim 7 , further comprising:
a first wiring that connects the first sensor electrode to the measurement circuit through the multi-layer substrate; and a second wiring that connects the second sensor electrode to the measurement circuit through the multi-layer substrate, wherein the measurement circuit is disposed on the second surface of the multi-layer substrate, and wherein the first wiring and the second wiring are disposed in a second inner layer provided between the first surface and the first inner layer of the multi-layer substrate.

9 . The electrostatic input device according to claim 8 , further comprising:
a third wiring disposed on the second surface of the multi-layer substrate and connecting the driving circuit to the plurality of electronic parts through the multi-layer substrate; and a grounding electrode disposed on the second surface at a position overlapping the first sensor electrode and the second sensor electrode in the plan view, wherein the grounding electrode includes:
a first grounding electrode portion made of a solid metal layer without any gap or opening clearance, the first grounding electrode portion surrounding the third wiring in a region within a predetermined distance from the third wiring in the plan view; and
a second grounding electrode portion made of a mesh-like metal layer with gaps and/or openings and formed continually to the first grounding electrode portion, the second grounding electrode portion being provided outside the region surrounding the third wiring.

10 . The electrostatic input device according to claim 1 , further comprising:
a plurality of the first sensor electrodes; a plurality of the second sensor electrodes, each surrounding corresponding one of the plurality of the first sensor electrodes; a plurality of the electronic parts disposed around each second sensor electrode; and a first shield electrode made of a solid metal layer without any gap or opening, the first shield electrode surrounding each second sensor electrode and the plurality of electronic parts disposed around the second sensor electrode in the plan view.

Assignees

• Alps Alpine Co Ltd

Inventors

• Takata Masahiro
• Shigetaka Hiroshi

Classifications

• H03K2217/960755

  Constructional details of capacitive touch and proximity switches · CPC title

• H03K2217/96015

  Constructional details for touch switches · CPC title

• H03K17/955

  using a capacitive detector · CPC title

• H03K17/962 Primary

  Capacitive touch switches · CPC title

• G06F3/0202

  Constructional details or processes of manufacture of the input device · CPC title