Pointing and data entry input device

• US 8,174,508 B2
• Filed: 11/19/2007
• Issued: 05/08/2012
• Est. Priority Date: 11/19/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Sinclair, Michael J., Voth, David W., Bittner, Ray A.
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): ABDIN, SHAHEDA A
• Application Number:
  US11/941,985
• Publication Number:
  US 20090128511A1
• Time in Patent Office: 1,632 Days
• Field of Search: 345/174, 345/213, 345/98, 178/18.01, 178/18.08, 178/18.05, 178/18.07, 463 37- 38
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0202 Constructional details or processes of manufacture of the input device
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/04886 by partitioning the display area of the touch-screen or the surface of the digitising tablet into independently controllable areas, e.g. virtual keyboards or menus
• CPC Class Codes: H01H 2003/0293 with an integrated touch switch
• CPC Class Codes: H01H 2217/01 Off centre actuation
• CPC Class Codes: H01H 2217/036 Plural multifunctional miniature keys for one symbol
• CPC Class Codes: H01H 2239/006 Containing a capacitive switch or usable as such
• CPC Class Codes: H03K 2217/96054 Double function: touch detection combined with detection of a movable element
• CPC Class Codes: H04M 1/23 Construction or mounting of dials or of equivalent devices; Means for facilitating the use thereof by improving visibility H04M1/22

Abstract

An input device includes an array of adjacent capacitive sensors arranged into rows and columns. Each capacitive sensor exhibits a capacitance characteristic when in proximity to a conductive element. A plurality of mechanical hysteresis mechanisms are each deposited on and in contact with each of the capacitive sensors and configured to be actuated by a corresponding push button. Each capacitive sensor exhibits an electrical characteristic upon actuation of the corresponding mechanical hysteresis mechanism. An insulating overlay layer positioned over the array of capacitive sensors and the plurality of mechanical hysteresis mechanisms defines each push button and defines a surface for accommodating the conductive element.

Claims

1. An input device comprising:

an array of adjacent capacitive sensors arranged into rows and columns, each capacitive sensor exhibiting a capacitance characteristic when in proximity to a conductive element;

a plurality of mechanical hysteresis mechanisms that are each deposited on and in contact with one of the capacitive sensors and configured to be actuated by a corresponding push button, each capacitive sensor discharging an electrical charge upon actuation of the corresponding mechanical hysteresis mechanism;

each mechanical hysteresis mechanism comprises a first portion is-coupled to a corresponding one of the capacitive sensors and a second portion spaced apart from the corresponding capacitive sensor, and a plurality of ground pads, each ground pad corresponding to one of the capacitive sensors and being positioned between the capacitive sensor and the second portion of the corresponding mechanical hysteresis mechanism coupled to the capacitive sensor, wherein actuation of each of the mechanical hysteresis mechanism causes the mechanical hysteresis mechanism to come into contact with the ground pad; and

an insulating overlay layer positioned over the array of capacitive sensors and the plurality of mechanical hysteresis mechanisms to define each push button and to define a surface for accommodating the conductive element.

2. The input device of claim 1, wherein the capacitance characteristic corresponds to a position of the conductive element on the surface of the insulating overlay layer.

3. The input device of claim 1, wherein each of the adjacent capacitive sensors arranged in rows and columns is coupled to another one of the capacitive sensors by a plurality of non-linear boundary edges.

4. The input device of claim 1, further comprising a controller, wherein each capacitive sensor is coupled to one of a plurality of input/output pins of the controller by a conductor.

5. The input device of claim 4, wherein each capacitive sensor is coupled to a power supply voltage.

6. The input device of claim 1, wherein each push button includes a protrusion for actuating the second portion of the corresponding mechanical hysteresis mechanism toward the corresponding ground pad.

7. A method of determining a position of a conductive element, the method comprising:

providing an input pad including an array of adjacent capacitive sensors arranged into rows and columns, each capacitive sensor exhibiting an increase in capacitance when in proximity to the conductive element;

providing mechanical hysteresis mechanism, each mechanical hysteresis mechanism corresponding to one of the capacitive sensors, each mechanical hysteresis mechanism having a first portion that is couple to the corresponding capacitive sensors, a second portion that is spaced apart from the corresponding capacitive sensor;

providing ground pads, each ground pad corresponding to the capacitive sensors and being positioned between the corresponding capacitive sensor and the second portion of the mechanical hysteresis mechanism,

each mechanical hysteresis mechanism coming into contact with the corresponding ground pad upon an actuation of the mechanical hysteresis mechanism, timing a to logic transition interval for each capacitive sensor representing a charge transition of the capacitive sensor from a first voltage representing a first logical value to a second voltage representing a second logical value;

generating capacitance values for each capacitive sensor abased on the logic transition interval of the capacitive sensor; and

deriving a position of the conductive element on the input pad based on the capacitance values of each sensor and a proportional contribution of each row and column of the array of adjacent capacitive sensors.

8. The method of claim 7, wherein generating capacitance values for each capacitive sensor comprises obtaining an average of raw capacitance values for each capacitive sensor over a period of time.

9. The method of claim 8, further comprising subtracting a minimum capacitance value from each averaged raw capacitance value for each sensor, the minimum capacitance value represents a capacitance value that each sensor will return when the conductive element is distal from the capacitive sensor.

10. The method of claim 9, further comprising computing the minimum capacitance value by:

storing a running statistical relation of high capacitance values for each capacitive sensor;

storing a running statistical relation of low capacitance values for each capacitive sensor;

comparing a new capacitance value to a mid point between the low and the high capacitance values to add the new capacitance value to one of the statistical relation of high and low capacitance values; and

selecting the statistical relation of low values as the minimum capacitance value.

11. The method of claim 9, further comprising computing the minimum capacitance value by:

storing a running statistically relative delta value of capacitance for the capacitive sensors, wherein the statistically relative delta value is the statistical relational difference between a statistical relation of low capacitance values and a statistical relation of high capacitance values;

comparing a new capacitance value to a threshold to determine if the new capacitance value be added to one of the statistical relation of low capacitance values and the statistically relative delta value; and

selecting the statistical relation of low values as the minimum capacitance value.

12. The method of claim 7, wherein each row and each column is assigned a weight.

13. An input device comprising:

an array of adjacent capacitive sensors arranged into rows and columns that provide capacitance information, each row and column including a corresponding weight such that a position of a conductive element is determined based on the capacitance information of the capacitive sensors and the corresponding weights;

a plurality of push buttons that each corresponds to one of the capacitive sensors;

a plurality of mechanical hysteresis mechanism, each mechanical hysteresis mechanism being deposited on and in contact with one of the capacitive sensors and configured to be actuated upon the actuation of one of the push button, each mechanical hysteresis mechanism having a first portion coupled to a corresponding one of the capacitive sensors and second portion spaced apart from the corresponding capacitive sensor;

a plurality of ground pads that each corresponds to one of the push buttons, each ground pad being positioned between the corresponding capacitive sensor and the second portion of the corresponding mechanical hysteresis mechanism, each capacitive sensor providing electrical information upon actuating its corresponding push button to cause electrical coupling between the capacitive sensor and the corresponding ground pad to discharge an electrical charge from the capacitive sensor through the corresponding ground pad; and

an insulating overlay layer that defines each push button and defines a surface for accommodating the conductive element.

14. The input device of claim 13, wherein each of the adjacent capacitive sensors arranged in rows and columns is coupled to another one of the capacitive sensors by a plurality of non-linear boundary edges.

15. The input device of claim 13, wherein the insulating overlay layer includes a plurality of cutouts for defining the push buttons.

16. The input device of claim 13, further comprising a controller, wherein each capacitive sensor is coupled to one of a plurality of input/output pins of the controller by a conductor and wherein each input/output pin of the controller is coupled to a power supply voltage through a resistor.