Sliding structure location on a pointing device corrected for non-linearity of measured differential
A pointing device has a pointing device surface and a sliding structure that moves with respect to the pointing device surface. A detector outputs a value that varies as the sliding structure moves with respect to the pointing device surface. A controller estimates the sliding structure location on the pointing device surface by calculating an approximate distance. The approximate distance is calculated by multiplying a measured differential of the value times a conversion constant. The controller adjusts the approximate distance to take into account non-linearity of the measured differential.
1 . A method for calculating a sliding structure location on a pointing device surface, the method comprising:
calculating an approximate distance by multiplying a measured differential times a conversion constant; and,
adjusting the approximate distance to take into account non-linearity of the measured differential.
2 . A method as in claim 1 wherein the measured differential is a measured capacitance differential.
3 . A method as in claim 1 wherein the measured differential is one of the following:
a magnetic field differential;
a resistance differential; or,
an inductance differential.
4 . A method as in claim 1 wherein adjusting the approximate distance is performed using a first order correction value.
5 . A method as in claim 1 wherein adjusting the approximate distance is performed using one or more tables.
6 . A method as in claim 1 wherein adjusting the approximate distance in an “x” direction is performed using the following equation:
If |A|<=Start, then
Delta X=A
If |A|>Start, then
If A>0, then
Delta X=A+(A−Start)*Slope
If A<0, then
Delta X=A+(A+Start)*Slope
wherein A is the approximate distance in the x direction, Delta X is an adjusted value in the x direction, “Start” is a threshold value and “Slope” is a first order correctional value constant.
7 . A method as in claim 6 wherein adjusting the approximate distance in a “y” direction is performed using the following equation:
If |B|<=Start, then
Delta X=B
If |B|>Start, then
If B>0, then
Delta X=B+(B−Start)*Slope
If B<0, then
Delta X=B+(B+Start)*Slope
wherein B is the approximate distance and Delta Y is an adjusted value in the Y direction.
8 . A pointing device, comprising:
a pointing device surface;
a sliding structure that moves with respect to the pointing device surface;
a detector that outputs a value that varies as the sliding structure that moves with respect to the pointing device surface; and
a controller that estimates the sliding structure location on the pointing device surface by calculating an approximate distance, the approximate distance being calculated by multiplying a measured differential of the value times a conversion constant, the controller adjusting the approximate distance to take into account non-linearity of the measured differential.
9 . A pointing device as in claim 8 wherein the measured differential is a measured capacitance differential.
10 . A pointing device as in claim 8 wherein the measured differential is one of the following:
a magnetic field differential;
a resistance differential; or, an inductance differential.
11 . A pointing device as in claim 8 wherein adjusting the approximate distance is performed using a first order correction value.
12 . A pointing device as in claim 8 wherein adjusting the approximate distance is performed using one or more tables.
13 . A pointing device as in claim 8 wherein adjusting the approximate distance in an “x” direction is performed using the following equation:
If |A|<=Start, then
Delta X=A
If |A|>Start, then
If A>0, then
Delta X=A+(A−Start)*Slope
If A<0, then
Delta X=A+(A+Start)*Slope
wherein A is the approximate distance in the x direction, Delta X is an adjusted value in the x direction, “Start” is a threshold value and “Slope” is a first order correctional value constant.
14 . A pointing device as in claim 13 wherein adjusting the approximate distance in a “y” direction is performed using the following equation:
If |B|<=Start, then
Delta X=B
If |B|>Start, then
If B>0, then
Delta X=B+(B−Start)*Slope
If B<0, then
Delta X=B+(B+Start)*Slope
wherein B is the approximate distance and Delta Y is an adjusted value in the Y direction.
15 . A computing device, comprising:
a pointing device, the pointing device including:
a pointing device surface;
a sliding structure that moves with respect to the pointing device surface;
means for generating a value that varies as the sliding structure moves with respect to the pointing device surface; and
means for calculating the sliding structure location on the pointing device surface by calculating an approximate distance, the approximate distance being calculated by multiplying a measured differential of the value times a conversion constant; wherein the approximate distance is adjusted to take into account non-linearity of the measured differential.
16 . A computing device as in claim 15 wherein the measured differential is a measured capacitance differential.
17 . A computing device as in claim 15 wherein adjusting the approximate distance is performed using a first order correction value.
18 . A computing device as in claim 15 wherein adjusting the approximate distance is performed using one or more tables.
19 . A computing device as in claim 15 wherein adjusting the approximate distance in an “x” direction is performed using the following equation:
If |A|<=Start, then
Delta X=A
If |A|>Start, then
If A>0, then
Delta X=A+(A−Start)*Slope
If A<0, then
Delta X=A+(A+Start)*Slope
wherein A is the approximate distance in the x direction, Delta X is an adjusted value in the x direction, “Start” is a threshold value and “Slope” is a first order correctional value constant.
20 . A computing device as in claim 15 wherein adjusting the approximate distance in a “y” direction is performed using the following equation:
If |B|<=Start, then
Delta X=B
If |B|>Start, then
If B>0, then
Delta X=B+(B−Start)*Slope
If B<0, then
Delta X=B+(B+Start)*Slope
wherein B is the approximate distance and Delta Y is an adjusted value in the Y direction.