# US 12,761,740 B2 · Pressing key detection system, device, method, and storage medium

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- Number: US 12,761,740 B2
- Document ID: US12761740B2
- Status: Granted
- Kind: B2
- Application number: 19/460,281
- Filed: 2026-01-26
- Published: 2026-06-04
- Granted: 2026-10-13
- Earliest claimed: 2024-09-03
- Assignees: Chipsemi Semiconductor (Ningbo) Co., Ltd.
- Applicants: Chipsemi Semiconductor (NingBo) Co., Ltd.
- Inventors: Kejia Liu; Yaoguo Zhang; Guofan Cheng; Fasi Sun; Bo Nie
- Web page: https://patentgrep.com/patent/US12761740B2

## CPC

- G06F 3/0202: {Constructional details or processes of manufacture of the input device}
- H03K 17/975: using a capacitive movable element
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

This application provides a pressing key detection system, device, method, and storage medium. The system includes at least one key, a driving circuit, and a detection circuit. Each key includes a base and a movement assembly. The movement assembly extends through a top surface of the base and reciprocates perpendicular to the top surface. The movement assembly includes a core shaft, and two conductor plates fixed relative to the core shaft. The base includes a casing, and a main electrode plate and a secondary electrode plate fixed opposite to the casing. The two conductor plates are respectively arranged opposite to the main electrode plate and the secondary electrode plate. The driving circuit is connected to the secondary electrode plate, and the detection circuit is connected to the main electrode plate. The driving circuit drives the secondary electrode plate to operate. This key arrangement improves accuracy of key displacement detection.

## Claims

### Claim 1

A key pressing detection system, comprising:
at least one key, a driving circuit, a detection circuit, and a processing unit;
each of the at least one key comprising a base and a movement assembly, the movement assembly extending through a top surface of the base and configured to reciprocate in a first direction perpendicular to the top surface, and the movement assembly comprising a core shaft, and two conductor plates opposite to the core shaft and fixed relative to the core shaft;
the base comprising a casing, a main electrode plate, and a secondary electrode plate both fixed relative to the casing, the two conductor plates being arranged opposite to the main electrode plate and to the secondary electrode plate, the secondary electrode plate, the two conductor plates, and the main electrode plate forming a target capacitor configured to generate capacitance signals that change in response to the core shaft reciprocating;
wherein the driving circuit is connected to the secondary electrode plate and configured to drive the secondary electrode plate, and the detection circuit is connected to the main electrode plate and configured to detect the capacitance signals of the target capacitor;
wherein the processing unit is connected to the detection circuit and configured to determine a displacement of the at least one key according to the capacitance signals of the target capacitor;
wherein each of the two conductor plates is arranged on a respective outer side wall of the core shaft, and the two conductor plates are connected to each other by wires;
wherein each of the secondary electrode plate and the main electrode plate is arranged on a respective inner side wall of the casing, the secondary electrode plate is arranged opposite to one of the two conductor plates, and the main electrode plate is arranged opposite to the other one of the two conductor plates;
wherein the main electrode plate comprises at least one first electrode plate and a second electrode plate, the secondary electrode plate, the two conductor plates, and the at least one first electrode plate form a first capacitor, and the secondary electrode plate, the two conductor plates, and the second electrode plate form a second capacitor;
the detection circuit is connected to the at least one first electrode plate and the second electrode plate of the main electrode plate, and the detection circuit is configured to detect a capacitance signal of the first capacitor and a capacitance signal of the second capacitor;
the capacitance signal of the first capacitor and the capacitance signal of the second capacitor are changed when the core shaft reciprocates; and
the at least one first electrode plate comprises two first electrode plates symmetrically arranged on both sides of the second electrode plate, one of the two first electrode plates is separated from the second electrode plate by a first gap, the other one of the two first electrode plates is separated from the second electrode plate by a second gap, and each of the first gap and the second gap extends in a second direction that is different from the first direction.

### Claim 2 (depends on 1)

The key pressing detection system according to claim 1, wherein the at least one key includes a plurality of keys, the plurality of keys are arranged in a matrix having N rows and M columns, wherein N and M are integers greater than 0, the driving circuit comprises N driving pins; and
the secondary electrode plate of each key of each of the rows is connected to a respective driving pin of the driving circuit.

### Claim 3 (depends on 1)

The key pressing detection system according to claim 1, wherein the two first electrode plates and the second electrode plate form an electrode plate assembly, and the main electrode plate comprises a plurality of electrode plate assemblies arranged on an inner side wall of the casing and arranged along a direction perpendicular to a reciprocating motion direction; and
wherein a first electrode plate of a respective electrode plate assembly of the plurality of electrode plate assemblies is arranged adjacent to and is integrated with a first electrode plate of a corresponding electrode plate assembly adjacent to the respective electrode plate assembly.

### Claim 4 (depends on 1)

The key pressing detection system according to claim 1, wherein the at least one key includes a plurality of keys, the plurality of keys are arranged in a matrix having N rows and M columns, wherein N and M are integers greater than 0, the driving circuit comprises N driving pins, and the detection circuit comprises M first detection pins and M second detection pins;
the secondary electrode plate of each key of each of the rows is connected to a respective driving pin of the driving circuit;
the at least one first electrode plate of the main electrode plate of each key of each of the columns is connected to a respective first detection pin of the detection circuit; and
the second electrode plate of the main electrode plate of each key of each of the columns is connected to a respective second detection pin of the detection circuit.

### Claim 5

An electronic device, comprising a key pressing detection system, wherein the key pressing detection system comprises at least one key, a driving circuit, a detection circuit, and a processing unit;
each of the at least one key comprising a base and a movement assembly, the movement assembly extending through a top surface of the base and configured to reciprocate in a first direction perpendicular to the top surface, and the movement assembly comprising a core shaft and two conductor plates opposite to the core shaft and fixed relative to the core shaft;
the base comprising a casing, a main electrode plate, and a secondary electrode plate both fixed relative to the casing, the two conductor plates being arranged opposite to the main electrode plate and to the secondary electrode plate, the secondary electrode plate, the two conductor plates, and the main electrode plate forming a target capacitor configured to generate capacitance signals that change in response to the core shaft reciprocating;
wherein the driving circuit is connected to the secondary electrode plate and configured to drive the secondary electrode plate, and the detection circuit is connected to the main electrode plate and configured to detect the capacitance signals of the target capacitor;
wherein the processing unit is connected to the detection circuit and configured to determine a displacement of the at least one key according to the capacitance signals of the target capacitor;
wherein each of the two conductor plates is arranged on a respective outer side wall of the core shaft, and the two conductor plates are connected to each other by wires;
wherein each of the secondary electrode plate and the main electrode plate is arranged on a respective inner side wall of the casing, the secondary electrode plate is arranged opposite to one of the two conductor plates, and the main electrode plate is arranged opposite to the other one of the two conductor plates;
wherein the main electrode plate comprises at least one first electrode plate and a second electrode plate, the secondary electrode plate, the two conductor plates, and the at least one first electrode plate form a first capacitor, and the secondary electrode plate, the two conductor plates, and the second electrode plate form a second capacitor;
the detection circuit is connected to the at least one first electrode plate and the second electrode plate of the main electrode plate, and the detection circuit is configured to detect a capacitance signal of the first capacitor and a capacitance signal of the second capacitor;
the capacitance signal of the first capacitor and the capacitance signal of the second capacitor are changed when the core shaft reciprocates; and
the at least one first electrode plate comprises two first electrode plates symmetrically arranged on both sides of the second electrode plate, one of the two first electrode plates is separated from the second electrode plate by a first gap, the other one of the two first electrode plates is separated from the second electrode plate by a second gap, and each of the first gap and the second gap extends in a second direction that is different from the first direction.

### Claim 6 (depends on 5)

The electronic device according to claim 5, wherein the at least one key includes a plurality of keys, the plurality of keys are arranged in a matrix having N rows and M columns, wherein N and M are integers greater than 0, the driving circuit comprises N driving pins; and
the secondary electrode plate of each key of each of the rows is connected to a respective driving pin of the driving circuit.

### Claim 7 (depends on 5)

The electronic device according to claim 5, wherein the two first electrode plates and the second electrode plate form an electrode plate assembly, and the main electrode plate comprises a plurality of electrode plate assemblies arranged on an inner side wall of the casing and arranged along a direction vertical to a reciprocating motion direction; and
wherein a first electrode plate of a respective electrode plate assembly of the plurality of electrode plate assemblies is arranged adjacent to and is integrated with a first electrode plate of a corresponding electrode plate assembly adjacent to the respective electrode plate assembly.

### Claim 8 (depends on 5)

The electronic device according to claim 5, wherein the at least one key is a plurality of keys, the plurality of keys are arranged in a matrix having N rows and M columns, wherein N and M are integers greater than 0, the driving circuit comprises N driving pins, the detection circuit comprises M first detection pins and M second detection pins;
the secondary electrode plate of each key of each of the rows is connected to a respective driving pin of the driving circuit;
the at least one first electrode plate of the main electrode plate of each key of each of the columns is connected to a respective first detection pin of the detection circuit; and
the second electrode plate of the main electrode plate of each key of each of the columns is connected to a respective second detection pin of the detection circuit.

### Claim 9

A key pressing detection method, applicable to a key pressing detection system, wherein the key pressing detection system comprises at least one key, a driving circuit, a detection circuit, and a processing unit;
each of the at least one key comprising a base and a movement assembly, the movement assembly extending through a top surface of the base and configured to reciprocate in a first direction perpendicular to the top surface, and the movement assembly comprising a core shaft, and two conductor plates opposite to the core shaft and fixed relative to the core shaft;
the base comprising a casing, a main electrode plate, and a secondary electrode plate both fixed relative to the casing, the two conductor plates being arranged opposite to the main electrode plate and to the secondary electrode plate, the secondary electrode plate, the two conductor plates, and the main electrode plate forming a target capacitor configured to generate capacitance signals that change in response to the core shaft reciprocating;
wherein the driving circuit is connected to the secondary electrode plate and configured to drive the secondary electrode plate, and the detection circuit is connected to the main electrode plate and configured to detect the capacitance signals of the target capacitor;
wherein the processing unit is connected to the detection circuit and configured to determine a displacement of the at least one key according to the capacitance signals of the target capacitor;
wherein each of the two conductor plates is arranged on a respective outer side wall of the core shaft, and the two conductor plates are connected to each other by wires;
wherein each of the secondary electrode plate and the main electrode plate is arranged on a respective inner side wall of the casing, the secondary electrode plate is arranged opposite to one of the two conductor plates, and the main electrode plate is arranged opposite to the other one of the two conductor plates;
wherein the main electrode plate comprises at least one first electrode plate and a second electrode plate, the secondary electrode plate, the two conductor plates, and the at least one first electrode plate form a first capacitor, and the secondary electrode plate, the two conductor plates, and the second electrode plate form a second capacitor;
the detection circuit is connected to the at least one first electrode plate and the second electrode plate of the main electrode plate, and the detection circuit is configured to detect a capacitance signal of the first capacitor and a capacitance signal of the second capacitor;
the capacitance signal of the first capacitor and the capacitance signal of the second capacitor are changed when the core shaft reciprocates;
the at least one first electrode plate comprises two first electrode plates symmetrically arranged on both sides of the second electrode plate, one of the two first electrode plates is separated from the second electrode plate by a first gap, and the other one of the two first electrode plates is separated from the second electrode plate by a second gap, and each of the first gap and the second gap extends in a second direction that is different from the first direction; and
wherein the key pressing detection method comprises:
detecting, by the detection circuit, the capacitance signals generated by the target capacitor; and
determining, by the processing unit, a pressing status of the at least one key based on the changes in the capacitance signals.

### Claim 10 (depends on 9)

The key pressing detection method according to claim 9, wherein the at least one key includes a plurality of keys, the plurality of keys are arranged in a matrix having N rows and M columns, N and M are integers greater than 0, the driving circuit comprises N driving pins;
the secondary electrode plate of each key of each of the rows is connected to a respective driving pin of the driving circuit.

### Claim 11 (depends on 9)

The key pressing detection method according to claim 9, wherein the two first electrode plates and the second electrode plate form an electrode plate assembly, and the main electrode plate comprises a plurality of electrode plate assemblies arranged on an inner side wall of the casing and arranged along a direction perpendicular to a reciprocating motion direction; and
wherein a first electrode plate of a respective electrode plate assembly of the plurality of electrode plate assemblies is arranged adjacent to and is integrated with a first electrode plate of a corresponding electrode plate assembly adjacent to the respective electrode plate assembly.

### Claim 12 (depends on 9)

The key pressing detection method according to claim 9, wherein the at least one key includes a plurality of keys, the plurality of keys are arranged in a matrix having N rows and M columns, wherein N and M are integers greater than 0, the driving circuit comprises N driving pins, and the detection circuit comprises M first detection pins and M second detection pins;
the secondary electrode plate of each key of each of the rows is connected to a respective driving pin of the driving circuit;
the at least one first electrode plate of the main electrode plate of each key of each of the columns is connected to a respective first detection pin of the detection circuit; and
the second electrode plate of the main electrode plate of each key of each of the columns is connected to a respective second detection pin of the detection circuit.