Pressure sensor for a digitizer pen
View Patent ↗A digitizer pen ( 100 ) has a pressure sensor ( 104 ) that includes a flexible first printed component ( 600 ) and a flexible second printed component ( 700 ), on which are printed or otherwise disposed traces of non-carbon ink. The non-carbon ink on at least one of the printed components is a resistive non-carbon ink ( 606 and 706 ). The first printed component has a circular sensor section ( 602 ) that opposes a circular sensor section ( 702 ) of the second printed component. The non-carbon ink on the circular sensor section of at least one of the printed components forms a pattern of pie-shaped traces ( 711–716 ) symmetrical about a center ( 1000 ) of the circular sensor section. A stylus ( 130 ) transfers force from a writing tip ( 136 ) to the pressure sensor, at or near the center of the circular sensor section, either directly or through an elastomer ( 148 ), and presses the circular sensor sections together. The area of the non-carbon ink on one circular sensor section thereby pressed into intimate contact with the non-carbon ink on the other circular sensor section is proportional to the force. The pressure sensor has two terminals ( 901 and 902 ) electrically coupled to the inks on the circular sensor sections such that the electrical resistance between the terminals is proportional to the pressure. The electrical resistance is approximately the same when the stylus transfers a force at the center of the circular sensor section or when the stylus transfers the same force off-centered ( 1005 ). An electrical resistance versus force curve ( 1400 ) is selectable by preselecting the size or the shape, or both, of the ink traces of the pie-shaped pattern. The abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims pursuant to 37 C.F.R. §172(b).
1. In a digitizer pen, a pressure sensor, comprising:
a first sensor section having a non-carbon ink disposed thereon; and
a circular second sensor section having a non-carbon ink disposed thereon, the second sensor section abutting the first sensor section, said second sensor section having a center with a plurality of traces of the non-carbon ink disposed thereon in a pattern symmetrical about the center of the sensor section.
2. The pressure sensor of claim 1 in which at least one of the first sensor section and the second sensor section has a resistive, non-carbon ink disposed thereupon.
3. The pressure sensor of claim 1 in which at least one of the first sensor section and the second sensor section is circular having a center and has a plurality of traces of the non-carbon ink disposed thereon in a pattern symmetrical about the center of the sensor section.
4. The pressure sensor of claim 3 in which at least one of the first sensor section and the second sensor section has a resistive, non-carbon ink disposed thereupon.
5. A pressure sensor for a digitizer pen, comprising:
a first sensor section having a conductive, non-carbon ink disposed thereon; and
a second sensor section having a resistive, non-carbon ink disposed thereon, the second sensor section abutting the first member, and in which the resistive, non-carbon ink includes
thermoplastic resin,
silver,
tin oxide, and
diethylene glycol monobutyl ether acetate.
6. The pressure sensor of claim 5 , including an elastomer abutting at least one of the first sensor section and the second sensor section.
7. A digitizer pen, comprising:
a pressure sensor mounted within the digitizer pen, the pressure sensor having output terminals, a circular first sensor section and a circular second sensor section abutting the circular first sensor section, in which at least one of the circular first sensor section and the circular second sensor section has a plurality of traces of a non-carbon ink disposed thereon in a pattern symmetrical about the center of the sensor section; and
a stylus movably mounted to the digitizer pen, the stylus having a writing tip for touching a sensing surface and an end, opposite the writing tip, for applying force to the pressure sensor, such that an electrical conductance between the output terminals is proportional to the force, and such that, the electrical conductance in response to a given amount of force applied by the end of the stylus to the pressure sensor at the center is substantially the same as the electrical conductance in response to the given amount of force applied by the end of the stylus to the pressure sensor off-centered.
8. The digitizer pen of claim 7 including a tip holder movably mounted to the digitizer pen, and in which the stylus is removably mounted to the tip holder, such that the electrical conductance in response to a given amount of force applied by tip holder to the pressure sensor at the center is substantially the same as the electrical conductance in response to the given amount of force applied by the tip holder to the pressure sensor off-centered.
9. The digitizer pen of claim 8 , in which the pressure sensor has a start-up pressure, such that the start-up pressure is determined in part by the shape of a face of the tip holder.
10. The digitizer pen of claim 7 , in which at least one of the circular first sensor section and the circular second sensor section has a resistive, non-carbon ink disposed thereupon.
11. The digitizer pen of claim 9 , in which the pressure sensor includes a first sensor section having a conductive, non-carbon ink disposed thereon; and a second sensor section having a resistive, non-carbon ink disposed thereon.
12. A pressure sensor in a digitizer pen, the digitizer pen including a stylus for applying force to the pressure sensor, the pressure sensor comprising:
a first circular sensor section having a plurality of traces of a non-carbon ink disposed thereon in a pattern symmetrical about the center of the sensor section, a second circular sensor section and
two output terminals, such that an electrical conductance between the two output terminals is responsive to force applied by the stylus on the pressure sensors, and such that a change in electrical conductance between the two output terminals in response to a change in force applied by the stylus to the pressure sensors is selectable by preselecting the shapes of the traces and the size of the traces.