Control apparatus of capacitive touch sensor

• US 9,031,510 B2
• Filed: 12/17/2012
• Issued: 05/12/2015
• Est. Priority Date: 12/19/2011
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Oda, Yuusuke
• Primary Examiner(s): Rego, Dominic E
• Application Number:
  US13/716,417
• Publication Number:
  US 20130171925A1
• Time in Patent Office: 876 Days
• Field of Search: 455 301- 305, 455/63.3, 455/71, 455/113, 455/131, 455/182.1, 455/192.1, 455/275, 455/313
• US Class Current: 455/63.3
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9606 using one electrode only per touch switch
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 15/06 by local oscillators of receivers

Abstract

A control apparatus of a capacitive touch sensor includes a capacitive sensor, a radio receiver, a setting unit, and a charge control unit. The capacitive sensor is coupled to a manipulation panel and detects an approach of a finger of a user to the manipulation panel and a touch of the finger on the manipulation panel. The radio receiver receives a radio broadcast at a radio receiving frequency. The setting unit sets a sensing frequency to a selected value, which is determined from a plurality of selectable sensing frequency values, corresponding to the radio receiving frequency. The charge control unit is coupled to a switching unit, and controls the switching unit to operate at the sensing frequency in order to charge and discharge an electrostatic capacitance generated between the capacitive sensor and the finger.

Claims

1. A control apparatus of a capacitive touch sensor comprising:

a capacitive sensor;

a radio receiver that receives a radio broadcast at a radio receiving frequency;

a setting unit that sets a sensing frequency corresponding to the radio receiving frequency of the radio receiver;

a charge control unit that controls a switching unit to perform a switching operation at the sensing frequency set by the setting unit in order to charge and discharge an electrostatic capacitance generated at the capacitive sensor; and

a first measuring unit that measures a field intensity level before the charge control unit controls the switching unit to perform the switching operation and measures a field intensity level after the charge control unit controls the switching unit to perform the switching operation, wherein

the capacitive sensor detects an approach manipulation to a manipulation panel or a touch manipulation on the manipulation panel, and

the setting unit sets the sensing frequency corresponding to a difference between the field intensity level measured before the switching operation by the first measuring unit and the field intensity level measured after the switching operation by the first measuring unit.

2. The control apparatus according to claim 1, further comprising:

a specifying unit that specifies the radio receiving frequency of the radio receiver corresponding to present position information,

wherein the setting unit sets the sensing frequency corresponding to the radio receiving frequency specified by the specifying unit.

3. The control apparatus according to claim 1, further comprising:

a selection unit that selects all of the radio receiving frequencies that are available,

wherein the setting unit sets the sensing frequency corresponding to each of the radio receiving frequencies selected by the selection unit.

4. The control apparatus according to claim 1,

wherein the setting unit sets the sensing frequency corresponding to the radio receiving frequency of the radio receiver under a condition that the approach manipulation or the touch manipulation is not detected by the capacitive sensor.

5. The control apparatus according to claim 1, further comprising:

a channel storage unit that stores a radio receiving frequency selected by the user and a time slot of the radio receiving frequency,

wherein the setting unit sets the sensing frequency corresponding to the radio receiving frequency and the time slot, which are stored in the channel storage unit.

6. The control apparatus according to claim 5, wherein

the channel storage unit stores the radio receiving frequency and the time slot for each individual user, and

the setting unit sets the sensing frequency corresponding to the radio receiving frequency and the time slot, which are stored for each individual user.

7. A control apparatus of a capacitive touch sensor comprising:

a capacitive sensor;

a radio receiver that receives a radio broadcast at a radio receiving frequency;

a setting unit that sets a sensing frequency corresponding to the radio receiving frequency of the radio receiver;

a charge control unit that controls a switching unit to perform a switching operation at the sensing frequency set by the setting unit in order to charge and discharge an electrostatic capacitance generated at the capacitive sensor; and

a measuring unit that controls the switching unit to perform the switching operation at respective switching frequencies that vary within a predetermined range and measures respective charge and discharge signals, each of which charges or discharges the electrostatic capacitance generated at the capacitive sensor, wherein

the capacitive sensor detects an approach manipulation to a manipulation panel or a touch manipulation on the manipulation panel, and

the setting unit sets the sensing frequency equal to the switching frequency under a condition that the charge and discharge signal measured by the second measuring unit and corresponding to the switching frequency has a high-frequency noise level lower than a predetermined level within a frequency band of the radio receiving frequency.

8. A control apparatus of a capacitive touch sensor comprising:

a capacitive sensor;

a radio receiver that receives a radio broadcast at a radio receiving frequency;

a setting unit that sets a sensing frequency corresponding to the radio receiving frequency of the radio receiver;

a charge control unit that controls a switching unit to perform a switching operation at the sensing frequency set by the setting unit in order to charge and discharge an electrostatic capacitance generated at the capacitive sensor; and

a storage unit that stores a predetermined sensing frequency set corresponding to the radio receiving frequency of the radio receiver, wherein

the capacitive sensor detects an approach manipulation to a manipulation panel or a touch manipulation on the manipulation panel, and

the setting unit sets the sensing frequency equal to the predetermined sensing frequency stored in the storage unit.

9. A control apparatus of a capacitive touch sensor comprising:

a capacitive sensor;

a radio receiver that receives a radio broadcast at a radio receiving frequency;

a setting unit that sets a sensing frequency corresponding to the radio receiving frequency of the radio receiver;

a charge control unit that controls a switching unit to perform a switching operation at the sensing frequency set by the setting unit in order to charge and discharge an electrostatic capacitance generated at the capacitive sensor; and

a specifying unit that specifies the radio receiving frequency of the radio receiver corresponding to present position information, wherein

the capacitive sensor detects an approach manipulation to a manipulation panel or a touch manipulation on the manipulation panel, and

the setting unit sets the sensing frequency corresponding to the radio receiving frequency specified by the specifying unit.

10. A control apparatus of a capacitive touch sensor comprising:

a capacitive sensor;

a radio receiver that receives a radio broadcast at a radio receiving frequency;

a setting unit that sets a sensing frequency corresponding to the radio receiving frequency of the radio receiver;

a charge control unit that controls a switching unit to perform a switching operation at the sensing frequency set by the setting unit in order to charge and discharge an electrostatic capacitance generated at the capacitive sensor; and

a channel storage unit that stores a radio receiving frequency selected by the user and a time slot of the radio receiving frequency, wherein

the capacitive sensor detects an approach manipulation to a manipulation panel or a touch manipulation on the manipulation panel, and

the setting unit sets the sensing frequency corresponding to the radio receiving frequency and the time slot, which are stored in the channel storage unit.

11. The control apparatus of the capacitive touch sensor in claim 10, wherein

the channel storage unit stores the radio receiving frequency and the time slot for each individual user, and

the setting unit sets the sensing frequency corresponding to the radio receiving frequency and the time slot, which are stored for each individual user.