Proximity detection device and proximity detection method

• US 20110055305A1
• Filed: 08/18/2010
• Published: 03/03/2011
• Est. Priority Date: 08/26/2009
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Matsushima, Kenichi
• Granted Patent: US 8,682,949 B2
• Time in Patent Office: Days
• US Class Current: 708/400
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

The device includes plural transmitting electrodes and receiving electrodes, a multiline driving unit that simultaneously applies periodic alternating voltages to at least two electrodes of the transmitting electrodes, a current measurement unit, a computing unit, and a control unit. The computing unit includes a linear computing unit that performs linear computation to convert the current values or amounts of accumulated charge measured in the current measurement unit into values in response to the electrostatic capacitances of the respective intersections between the transmitting electrodes and the receiving electrodes, and a proximity computing unit that obtains the approach determination or the approach position of the object toward the detection area from an output of the linear computing unit. The linear computing unit includes a memory unit that stores an interim result of the computation to be read out at plural times.

Claims

1. A proximity detection device of obtaining an approach determination or an approach position of an object, comprising:

plural transmitting electrodes corresponding to one dimension of two dimensions in a detection area on a supporting unit and receiving electrodes corresponding to the other dimension;

a multiline driving unit that simultaneously applies periodic alternating voltages to at least two electrodes of the transmitting electrodes;

a current measurement unit that measures currents or amounts of accumulated charge from the receiving electrodes in synchronization with driving to the transmitting electrodes;

a computing unit that obtains the approach determination or the approach position of the object toward the detection area by converting the current values or the amounts of accumulated charge measured in the current measurement unit into values in response to electrostatic capacitances of respective intersections between the transmitting electrodes and the receiving electrodes; and

a control unit that manages statuses and sequences of the multiline driving unit, the current measurement unit, and the computing unit,

wherein the computing unit includes

a linear computing unit that performs linear computation to convert the current values or the amounts of accumulated charge measured in the current measurement unit into values in response to the electrostatic capacitances of the respective intersections between the transmitting electrodes and the receiving electrodes, and

a proximity computing unit that obtains the approach determination or the approach position of the object toward the detection area from an output of the linear computing unit, and

the linear computing unit includes a memory unit that stores an interim result of the computation to be read out at plural times.

2. The proximity detection device according to claim 1, wherein the linear computing unit performs fast Hadamard transform or transform equal to the fast Hadamard transform.

3. The proximity detection device according to claim 1, wherein a pattern driven by the multiline driving unit is an inverse matrix of an Hadamard matrix or an inverse matrix of a submatrix of an Hadamard matrix.

4. The proximity detection device according to claim 2, wherein a transmission voltage matrix that determines a pattern driven by the multiline driving unit is an Hadamard matrix according to the Sylvester'"'"'s construction method, a matrix in which rows or columns of an Hadamard matrix according to the Sylvester'"'"'s construction method are exchanged, or a submatrix thereof formed by multiplying a specified row by “

−

1”

, and computation equal to multiplication by “

−

1”

of measurement values of the current measurement unit corresponding to the row multiplied by “

−

1”

is performed in the fast Hadamard transform or the equal transform to the fast Hadamard transform.

5. The proximity detection device according to claim 2, wherein a transmission voltage matrix that determines a pattern driven by the multiline driving unit is an Hadamard matrix according to the Sylvester'"'"'s construction method, a matrix in which rows or columns of an Hadamard matrix according to the Sylvester'"'"'s construction method are exchanged, or a submatrix thereof formed by multiplying a specified column by “

−

1”

, and computation equal to multiplication by “

−

1”

of conversion values corresponding to the column multiplied by “

−

1”

is performed in the fast Hadamard transform or the equal transform to the fast Hadamard transform.

6. Information equipment comprising an input device including the proximity detection device according to claim 1.

7. The information equipment according to claim 6, including a cellular phone.

8. The information equipment according to claim 6, including a multimedia player.

9. The information equipment according to claim 6, including a navigation system.

10. The information equipment according to claim 6, including a computer.

11. A proximity detection method of obtaining an approach determination or an approach position of an object, comprising:

simultaneously applying periodic alternating voltages to plural transmitting electrodes corresponding to one dimension of two dimensions in a detection area for detection of the approach of the object;

measuring currents or amounts of accumulated charge from receiving electrodes corresponding to the other dimension in synchronization with driving to the transmitting electrodes; and

performing linear computation by fast Hadamard transform, performing conversion into values responding to electrostatic capacitances of the respective intersections between the transmitting electrodes and the receiving electrodes, and performing computation to obtain the approach determination or the approach position of the object toward the detection area.

12. The proximity detection method according to claim 11, wherein, in the computation, the fast Hadamard transform performs computation of multiplying at least one specified value of a computation table by “

−

1”

.

13. The proximity detection method according to claim 11, wherein, in the computation, computation equal to computation of multiplying at least one measurement value at the current driving and measurement step corresponding to the row as the one dimension by “

−

1”

.

14. The proximity detection method according to claim 11, wherein, in the computation, computation equal to computation of multiplying at least one conversion value corresponding to the column as the other dimension by “

−

1”

.

15. The proximity detection method according to claim 11, wherein, in the computation, an inverse matrix of a pattern driven in multiline is a submatrix of a matrix equal to an Hadamard matrix.