Computer mouse or keyboard input device utilizing capacitive sensors
First Claim
1. A sensor for capacitively sensing the position in a continuous range of positions of an object on a surface of an input device, which comprises:
- an array of electrodes on said surface;
an insulating layer covering said electrodes;
means connected to said electrodes for measuring a capacitance value for each said electrode;
means responsive to said measuring means for comparing said capacitance values with a first preset threshold and, if at least one of said capacitance values exceeds said first preset threshold, for calculating the position of a centroid of capacitance for said array from said measured capacitance values, said first preset threshold being set at a capacitance value that is exceeded for a given electrode only when said object is close to or touching said given electrode, said centroid of capacitance being the first moment of the distribution of said capacitance values in said array and representing substantially the position of said object on said surface; and
means responsive to said calculating means and connected to utilizing means for sending said centroid of capacitance position to said utilizing means.
6 Assignments
0 Petitions
Accused Products
Abstract
A computer input device for use as a computer mouse or keyboard comprises a thin, insulating surface covering an array of electrodes. Such electrodes are arranged in a grid pattern and can be connected in columns and rows. Each column and row is connected to circuitry for measuring the capacitance seen by each column and row. The position of an object, such as a finger or handheld stylus, with respect to the array is determined from the centroid of such capacitance values, which is calculated in a microcontroller. For applications in which the input device is used as a mouse, the microcontroller forwards position change information to the computer. For applications in which the input device is used as a keyboard, the microcomputer identifies a key from the position of the touching object and forwards such key identity to the computer.
474 Citations
10 Claims
-
1. A sensor for capacitively sensing the position in a continuous range of positions of an object on a surface of an input device, which comprises:
-
an array of electrodes on said surface; an insulating layer covering said electrodes; means connected to said electrodes for measuring a capacitance value for each said electrode; means responsive to said measuring means for comparing said capacitance values with a first preset threshold and, if at least one of said capacitance values exceeds said first preset threshold, for calculating the position of a centroid of capacitance for said array from said measured capacitance values, said first preset threshold being set at a capacitance value that is exceeded for a given electrode only when said object is close to or touching said given electrode, said centroid of capacitance being the first moment of the distribution of said capacitance values in said array and representing substantially the position of said object on said surface; and means responsive to said calculating means and connected to utilizing means for sending said centroid of capacitance position to said utilizing means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A touch-sensitive input device for a computer, which comprises:
-
an array of electrodes on a surface of said input device, said electrodes being arranged in rows and columns; an insulating layer covering said electrodes; means connected to said electrodes for measuring a capacitance value for each said electrode; means responsive to said measuring means for comparing said capacitance values with a first preset threshold and, if at least one of said capacitance values exceeds said first preset threshold, for calculating the coordinates of a centroid of capacitance for said array from said measured capacitance values, said centroid of capacitance corresponding to the position of a finger or other object touching said surface, said first preset threshold being set at a capacitance value that is exceeded for a given electrode only when said finger or other object is close to or touching said surface in the vicinity of said given electrode, said centroid of capacitance being the first moment of the distribution of said capacitance values in said array and representing substantially the position of said object in a continuous range of positions on said surface; and means responsive to said calculating means and connected to said computer for sending information to said computer indicative of or derived from said calculated coordinates.
-
Specification