Proximity detection device and proximity detection method

• US 8,682,949 B2
• Filed: 08/18/2010
• Issued: 03/25/2014
• Est. Priority Date: 08/26/2009
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Matsushima, Kenichi
• Primary Examiner(s): Mai, Tan V.
• Application Number:
  US12/806,653
• Publication Number:
  US 20110055305A1
• Time in Patent Office: 1,315 Days
• Field of Search: 708/400
• 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

A proximity detection device has transmitting and receiving electrodes and a multiline driving unit that simultaneously applies periodic alternating voltages to at least two of the transmitting electrodes. A measurement unit measures currents or amounts of accumulated charge from the receiving electrodes in synchronization with the simultaneous application of periodic alternating voltages to the at least two transmitting electrodes by the multiline driving unit. A linear computing unit performs linear computation of measurement results from a measurement unit in response to electrostatic capacitances of respective intersections between the transmitting and receiving electrodes. The linear computing unit has a memory unit that stores an output of the linear computation for readout at plural times. A proximity computing unit performs a computation to determine an approach and/or a position of an object relative to a detection area based on the output from the linear computing unit stored in the memory unit.

Claims

1. A proximity detection device for detecting an approach and/or a position of an object, the proximity detection device comprising:

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

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

a current measurement unit that measures current values or amounts of accumulated charge from the receiving electrodes in synchronization with driving of the at least two transmitting electrodes;

a computing unit that calculates the approach and/or the position of the object toward the detection area by converting the current values or the amounts of accumulated charge measured by 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 by 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 computes the approach and/or the position of the object toward the detection area from an output of the linear computing unit, and

wherein the linear computing unit includes a memory unit that stores an interim result of the linear computation performed by the linear computing unit so as to allow the interim result to be read out at plural times.

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

3. 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 a 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 transform equal to the fast Hadamard transform.

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 column by “

−

1”

, and a 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 transform equal to the fast Hadamard transform.

5. 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.

6. An 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 having the input device.

8. The information equipment according to claim 6, including a multimedia player having the input device.

9. The information equipment according to claim 6, including a navigation system having the input device.

10. The information equipment according to claim 6, including a computer having the input device.

11. An information equipment comprising:

a display that outputs information and has a detection area;

a proximity detection device according to claim 1 that receives an input from the detection area of the display and detects an approach and/or a location of an object relative to the detection area; and

a processing unit that controls operation of the proximity detection device and the display output.

12. A proximity detection method for detecting an approach and/or a 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 of the two dimensions in the detection area in synchronization with driving of the transmitting electrodes; and

performing linear computation by a fast Hadamard transform;

performing conversion into values in response to electrostatic capacitances of respective intersections between the transmitting electrodes and the receiving electrodes, and performing computation to detect the approach and/or the position of the object toward the detection area.

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

−

1”

.

14. The proximity detection method according to claim 12, wherein a computation equal to multiplication by “

−

1”

of at least one measurement value from the measurement step corresponding to a row of the Hadamard transform is multiplied by “

−

1”

.

15. The proximity detection method according to claim 12, wherein a computation equal to multiplication by “

−

1”

of at least one conversion value corresponding to a column of the Hadamard transform is multiplied by “

−

1.”

.

16. The proximity detection method according to claim 12, wherein an inverse matrix of a pattern driven in multiline during the simultaneous application of the periodic alternating voltages is a submatrix of a matrix equal to an Hadamard matrix.

17. A proximity detection device for detecting an approach and/or a position of an object relative to a detection area, the proximity detection device comprising:

a plurality of transmitting electrodes and receiving electrodes associated with the detection area;

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

a measurement unit that measures magnitudes of currents or amounts of accumulated charge from the plurality of receiving electrodes in synchronization with the simultaneous application of periodic alternating voltages to the at least two transmitting electrodes by the multiline driving unit;

a linear computing unit that performs linear computation of measurement results from the measurement unit in response to electrostatic capacitances of respective intersections between the transmitting electrodes and the receiving electrodes, the linear computing unit having a memory unit that stores an output of the linear computation for readout at plural times; and

a proximity computing unit that performs a computation to determine an approach and/or a position of an object relative to the detection area based on the output from the linear computing unit stored in the memory unit.

18. The proximity detection device according to claim 17, wherein the linear computing unit performs a fast Hadamard transform or a transform equal to the fast Hadamard transform.

19. The proximity detection device according to claim 17, 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.

20. An information equipment comprising:

a display that outputs information;

a proximity detection device according to claim 17 that receives an input from a detection area of the display and detects an approach and/or a location of an object relative to the detection area; and

a processing unit that controls operation of the proximity detection device and the display output.