Digitizer tablet with pressure stylus

Claim 2

In a digitizer tablet comprising an electrode array, a pointing device whose position is to be located with respect to the array and whose applied pressure is to be determined with respect to the tablet, and means for energizing the array and tablet to generate position and pressure signals representative, respectively, of the pointing device position and pressure, said pointing device having a linear transducer for converting applied pointing device pressure into electrical signals linearly related to the applied pressure, the improvement comprising: (a) means for processing the transducer electrical signals to convert their linear relation to pointing device pressure to a substantially logarithmic relation.

Claim 3

The digitizer tablet of claim 1, further comprising: (b) means for storing the logarithmically converted transducer signals.

Claim 4

In a digitizer tablet comprising an electrode array, a pointing device whose position is to be located with respect to the array and whose applied pressure is to be determined with respect to the tablet, and means for energizing the array and tablet to generate position and pressure signals representative, respectively, of the pointing device position and pressure, said pointing device having a linear transducer for converting applied pointing device pressure into electrical signals linearly related to the applied pressure, the improvement comprising: (a) means for digitizing the transducer electrical signals, (b) means for processing the digitized transducer signal value to convert their linear relation to applied pointing device pressure to a logarithmic relation, (c) means for storing the logarithmically converted digitized transducer signals.

Claim 5

In a digitizer tablet comprising an electrode array, a pointing device whose position is to be located with respect to the array and whose applied pressure is to be determined with respect to the tablet, and means for energizing the array and tablet to generate position and pressure signals representative, respectively, of the pointing device position and pressure, said pointing device having a linear transducer for converting applied pointing device pressure into electrical signals linearly related to the applied pressure, the improvement comprising: (a) means for digitizing the transducer electrical signals, (b) means for processing the digitized transducer signal value to convert their linear relation to applied pointing device pressure to a logarithmic relation, (c) means for storing the logarithmically converted digitized transducer signals.

Claim 6

The digitizer tablet as claimed in claim 3, wherein the digitizing means comprises means for generating a count linearly related to the pointing device pressure, and the conversion processing means comprises means for converting the linearly related count to a logarithmically related count.

Claim 7

The digitizer tablet as claimed in claim 4, wherein the conversion processing means include means for dividing the linearly related count range into a plurality of sub-ranges which increase in range value from low to high count values.

Claim 8

The digitizer tablet as claimed in claim 5, wherein the logarithmically related count outputted for each sub-range is calculated by a different formula.

Claim 9

The digitizer tablet of claim 6, wherein the logarithmically related count outputted for the lowest sub-range is zero.

Claim 10

The digitizer tablet as claimed in claim 4, wherein the conversion processing means comprises means for multiplying the log of linearly related count by a constant.

Claim 11

The digitizer tablet as claimed in claim 3, further comprising means for enabling and disabling the logarithmically related conversion means.

Claim 12

In a digitizer tablet comprising an electrode array, a pointing device whose position is to be located with respect to the array and whose applied pressure is to be determined with respect to the tablet, and means for energizing the array and tablet to generate position and pressure signals representative, respectively, of the pointing device position and pressure, said pointing device having a linear transducer for converting applied pointing device pressure into electrical signals linearly related to the applied pressure, the improvement comprising: (a) means for digitizing the transducer electrical signals, (b) means for processing the digitized transducer signal values, to convert their linear relation to a substantially logarithmic relation, (c) means for enabling and disabling the logarithmic conversion processing means to output a logarithmically related value when enabled and a linearly related value when disabled.

Claim 13

In a digitizer tablet comprising an electrode array, a pointing device whose position is to be located with respect to the array and whose applied pressure is to be determined with respect to the tablet, and means for energizing the array and tablet to generate position and pressure signals representative, respectively, of the pointing device position and pressure, said pointing device having a linear transducer for converting applied pointing device pressure into electrical signals linearly related to the applied pressure, the improvement comprising: (a) means for digitizing the transducer electrical signals, (b) means for processing the digitized transducer signal values, to convert their linear relation to a substantially logarithmic relation, (c) means for enabling and disabling the logarithmic conversion processing means to output a logarithmically related value when enabled and a linearly related value when disabled.

Claim 14

The digitizer tablet of claim 10, wherein the enabling and disabling means is programmable.

Claim 19

The method of claim 13, further comprising the step: (e) storing the count obtained in step (c) or step (d).

Claim 22

The method for operating a digitizer tablet as claimed in claim 15 wherein step(a) comprises the steps of: (c) converting the output signal into a count value and providing means to establish a sequence of sub-ranges of count values varying from low to high sub-ranges, (d) determining into which sub-range the count of step (c) falls, (e) processing the count of step(c) in accordance with the determined sub-range of step(d), the processing being different for each sub-range to produce an output which is logarithmically related to the count of step(c), said output increasing in smaller increments as the sub-ranges increases from low to high values.

Claim 23

The method of claim 16, wherein the outputs of the beginning and end sub-ranges are discarded.

Claim 24

The method of claim 17 wherein a 10-bit A/D converter is provided, and the steps (c), (d) and (e) are carried out in accordance with the following table: ______________________________________ INPUT COUNT SUB-RANGES OUTPUT COUNT ______________________________________ 0-100 0 100-200 (Count - 100) 200-300 100 + (Count - 200)/2 300-550 150 + (Count - 300)/4 550-900 213 + (Count - 550)/8 900-1024 256 ______________________________________

Claim 25

The method of claim 15, wherein step (a) is carried out by converting the transducer signal to a count value, and multiplying the log of the count value by a constant.

Claim 26

The method of claim 15, further comprising the step of disabling the converting step to output a linearly related signal.

Claim 27

In a digitizer tablet comprising an electrode array, a pointing device whose position is to be located with respect to the array and whose applied pressure is to be determined with respect to the tablet, and means for energizing the array and tablet to generate position and pressure signals representative, respectively, of the pointing device position and pressure, the improvement comprising: (a) means in the tablet for receiving and converting the pressure signals generated by the pointing device into output data values which are substantially logarithmically related to the applied pointing device pressure.

Claim 28

In a digitizer tablet comprising an electrode array, a pointing device whose position is to be located with respect to the array and whose applied pressure is to be determined with respect to the tablet, and means for energizing the array and tablet to generate position and pressure signals representative, respectively, of the pointing device position and pressure, the improvement comprising: (a) means in the tablet for receiving and converting the pressure signals generated by the pointing device into output data values which are substantially logarithmically related to the applied pointing device pressure.

Claim 29

The digitizer tablet of claim 21, further comprising means for selectively outputting from the tablet linear or logarithmically related signals.