# US 2014/0152627 A1 · Electromagnetic Pointer and Control Method Thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152627 A1 - Document ID: US20140152627A1 - Status: Published application - Kind: A1 - Application number: 13/747,074 - Filed: 2013-01-22 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Waltop International Corporation - Applicants: Waltop International Corporation - Inventors: A-Li Wong; CHIH-JEN LI; CHIA-JUI YEH - Web page: https://patentgrep.com/patent/US20140152627A1 ## CPC - G06F 3/03545: {Pens or stylus} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An electromagnetic pressure-sensitive pointer is disclosed. The electromagnetic pointer comprises a pen core and an oscillating circuit. The pointer core has a pointer tip. The oscillating circuit comprises a plurality of conductive terminals and a conductor. A capacitance of the oscillating circuit is increased through the contact between the conductive terminals and the conductor as a force is applied upon the pointer tip. When pointer's tip is been pressed, the pointer's frequency will have an obvious transition while its pressure-sensitivity is maintained. ## Claims ### Claim 1 A control method for an electromagnetic pointer, comprising: providing an electromagnetic pointer and an input apparatus, the electromagnetic pointer comprising: a core; and an oscillation circuit comprising a plurality of conductive terminals and a conductive device, a capacitance of the oscillation circuit being increased through the core pushing the conductive device to connect the conductive terminals; and applying a tip of the core against the input apparatus to push the conductive device to connect the conductive terminals and to increase the capacitance of the oscillation circuit so as to suddenly change a frequency of the oscillation circuit. ### Claim 2 (depends on 1) The control method of claim 1, wherein an inductance of the oscillation circuit is increased when a force applied upon the tip of the core increases. ### Claim 3 (depends on 1) The control method of claim 1, wherein an inductance of the oscillation circuit is decreased when a force applied upon the tip of the core increases. ### Claim 4 (depends on 1) The control method of claim 1, wherein the input apparatus and the electromagnetic pointer activate a writing function when the frequency of the oscillation circuit is suddenly changed. ### Claim 5 (depends on 1) The control method of claim 1, wherein the conductive device comprises a cone spring or a conductive rubber. ### Claim 6 (depends on 1) The control method of claim 1, wherein the input apparatus comprises a smart mobile communication device, a digitizer or a tablet or an eBook. ### Claim 7 An electromagnetic pointer, comprising: a core having a tip; and an oscillation circuit comprising a plurality of conductive terminals and a conductive device, a capacitance of the oscillation circuit being increased through the core pushing the conductive device to connect the conductive terminals so as to suddenly change a frequency of the oscillation circuit. ### Claim 8 (depends on 7) The electromagnetic pointer of claim 7, wherein the conductive device connects the conductive terminals so as to increase the capacitance of the oscillation circuit via connecting a capacitor in parallel with the oscillation circuit. ### Claim 9 (depends on 7) The electromagnetic pointer of claim 7, wherein an inductance of the oscillation circuit is increased when a force applied upon the tip of the core increases. ### Claim 10 (depends on 7) The electromagnetic pointer of claim 7, wherein an inductance of the oscillation circuit is decreased when a force applied upon the tip of the core increases. ### Claim 11 (depends on 7) The electromagnetic pointer of claim 7, wherein the input apparatus and the electromagnetic pointer activate a writing function when the frequency of the oscillation circuit is suddenly changed. ### Claim 12 (depends on 7) The electromagnetic pointer of claim 7, wherein the conductive device comprises a cone spring or a conductive rubber. ### Claim 13 (depends on 7) The electromagnetic pointer of claim 7, wherein the input apparatus comprises a smart mobile communication device, a digitizer, a tablet or an eBook. ### Claim 14 A method for determining a frequency variation mode of an electromagnetic pointer, comprising: detecting a frequency fn of an electromagnetic pointer; judging whether the frequency fn is smaller than a tip-on threshold frequency fon which a writing trace starts to appear; judging whether the frequency fn is smaller than an upper limit frequency fUB which is designated as the frequency when a first stage of a switch of the electromagnetic pointer is turned on; and judging whether the frequency fn is smaller than the lower limit frequency fLB which is designated as the frequency when a second stage of a switch of the electromagnetic pointer is turned on. ### Claim 15 (depends on 14) The method of claim 14, wherein a status of the electromagnetic pointer that the switch is not turned on is determined when the frequency fn is not smaller than the tip-on threshold frequency fon. ### Claim 16 (depends on 14) The method of claim 14, wherein a status of the electromagnetic pointer that the tip is being pressed is determined when the frequency fn is not smaller than the upper limit frequency fLB. ### Claim 17 (depends on 14) The method of claim 14, wherein a status of the electromagnetic pointer that the first stage of the switch is turned on is determined when the frequency fn is not smaller than the lower limit frequency fLB. ### Claim 18 (depends on 14) The method of claim 14, wherein a status of the electromagnetic pointer that the second stage of the switch is turned on is determined when the frequency fn is smaller than the lower limit frequency fLB. ### Claim 19 A method for dynamically adjusting tip pressure-sensitive levels of an electromagnetic pointer, comprising: comparing a frequency fn and a minimum pressure-sensitive level frequency f1 of the electromagnetic pointer; judging whether the frequency fn is larger than the minimum pressure-sensitive level frequency f1; judging whether the frequency fn is larger than a maximum pressure-sensitive level frequency f2; refreshing the maximum pressure-sensitive level frequency f2 so that the frequency fn is a new maximum pressure-sensitive level frequency if the frequency fn is larger than the maximum pressure-sensitive level frequency f2; and calculating tip pressure-sensitive levels of the electromagnetic pointer according to the new maximum pressure-sensitive level frequency and the minimum pressure-sensitive level frequency f1. ### Claim 20 (depends on 19) The method of claim 19 further comprising a step of refreshing the minimum pressure-sensitive level frequency f1 which the electromagnetic pointer is able to draw the minimum width of writing trace so that the frequency fn is a new minimum pressure-sensitive level frequency if the frequency fn is not larger than the minimum pressure-sensitive level frequency f1. ### Claim 21 (depends on 20) The method of claim 20 further comprising a step of calculating tip pressure-sensitive levels of the electromagnetic pointer according to the maximum pressure-sensitive level frequency f2 and the new minimum pressure-sensitive level frequency. ### Claim 22 (depends on 19) The method of claim 19 further comprising a step of calculating tip pressure-sensitive levels of the electromagnetic pointer according to the minimum pressure-sensitive level frequency f1 and the maximum pressure-sensitive level frequency f2 if the frequency fn not larger than the maximum pressure-sensitive level frequency f2.