Operational direction detecting device

• US 8,149,226 B2
• Filed: 05/14/2009
• Issued: 04/03/2012
• Est. Priority Date: 11/15/2006
• Status: Active Grant

• Current Assignee: Alps Alpine Co., Ltd.
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Oki, Toshiyuki
• Primary Examiner(s): Mengistu, Amare
• Assistant Examiner(s): Sharifi-Tafreshi, Koosha
• Application Number:
  US12/466,352
• Publication Number:
  US 20090225055A1
• Time in Patent Office: 1,055 Days
• Field of Search: 345/173, 345/174, 178/18.01, 178/18.03, 178/18.06, 178/18.05, 178/18.07, 341/33, 715700-702, 715/863
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0444 using a single conductive element covering the whole sensing surface, e.g. by sensing the electrical current flowing at the corners

Abstract

An operational direction detecting device includes a device body that includes an operational area operable in two or more directions, two or more detection electrode/drive electrode pairs that are formed at direction detecting positions of the operational area and form capacitance between a detection electrode and a drive electrode, and a control unit that decides an entrance direction of an object to be detected from capacitance acquired by each of the two or more detection electrode/drive electrode pairs when an object to be detected performing an operation enters the operational area. The control unit decides the direction of the area corresponding to larger capacitance as the entrance direction of the object to be detected when the composite capacitance of capacitances acquired at the two or more detection electrode/drive electrode pairs exceeds a first predetermined value.

Claims

1. An operational direction detecting device for determining an entrance direction of an object performing an operation, the device comprising:

a device body that includes an operational area operable in at least two directions, the operational area including at least two sub-areas corresponding to the at least two directions;

at least two electrode pairs, each electrode pair being provided for corresponding one of the at least two sub-areas, each electrode pair including a drive electrode and a detection electrode, a capacitance being formed between the detection electrode and the drive electrode adjacent each other; and

a control unit configured to determine the entrance direction of the object from a capacitance acquired by each of the at least two electrode pairs when the object enters the operational area,

wherein the control unit determines the direction corresponding to the sub-area having a largest capacitance as the entrance direction of the object when a composite capacitance of the capacitances acquired by the at least two electrode pairs exceeds a first predetermined value,

and wherein the determination of the entrance direction of the object is maintained when the composite capacitance becomes smaller than the first predetermined value after exceeding the first predetermined value, if a time period during which the composite capacitance is smaller than the first predetermined value is shorter than a predetermined time period.

3. The operational direction detecting device according to claim 1, wherein the at least two electrode pairs comprises four electrode pairs, and operations in four directions are detected.

2. An operational direction detecting device for determining an entrance direction of an object performing an operation, the device comprising:

a device body that includes an operational area operable in at least two directions, the operational area being divided into at least two sub-areas corresponding to the at least two directions;

at least two electrode pairs, each electrode pair being provided for corresponding one of the at least two sub-areas, each electrode pair including a drive electrode and a detection electrode, a capacitance being formed between the detection electrode and the drive electrode adjacent each other; and

a control unit configured to determine the entrance direction of the object from a capacitance acquired by each of the at least two electrode pairs when the object enters the operational area,

wherein the control unit determines the direction corresponding to the sub-area having a largest capacitance as the entrance direction of the object when a differential value of a composite capacitance of the capacitances acquired by the at least two electrode pairs exceeds a first predetermined value.

4. The operational direction detecting device according to claim 2,

wherein the determination of the entrance direction of the object is maintained when the composite capacitance becomes smaller than the first predetermined value after exceeding the first predetermined value, if a time period during which the composite capacitance is smaller than the first predetermined value is shorter than a predetermined time period.

5. An operational direction detecting device for determining an entrance direction of an object performing an operation, the device comprising:

a device body that includes an operational area operable in at least two directions, the operational area including at least two sub-areas corresponding to the at least two directions;

an electrode pair provided for each of the at least two sub-areas, each electrode pair including a drive electrode and a detection electrode, a capacitance being formed between the detection electrode and the drive electrode adjacent each other; and

a control unit configured to determine the entrance direction of the object from a capacitance acquired by each of the at least two electrode pairs when the object enters the operational area,

wherein the control unit determines the direction corresponding to the sub-area having a largest capacitance as the entrance direction of the object when a composite capacitance of the capacitances acquired by the at least two electrode pairs exceeds a first predetermined value.

6. The operational direction detecting device according to claim 5, further comprising:

a drive circuit configured to apply a drive voltage having a frequency to each drive electrode; and

a detection circuit connected to each detection electrode and maintained at a predetermined reference voltage.