Active stylus for touch sensing applications

• US 9,158,393 B2
• Filed: 12/17/2013
• Issued: 10/13/2015
• Est. Priority Date: 12/18/2012
• Status: Active Grant

• Current Assignee: Logitech Europe S A (Logitech International SA)
• Original Assignee: Logitech Europe S A (Logitech International SA)
• Inventors: Vlasov, Maxim
• Primary Examiner(s): CERULLO, LILIANA P
• Application Number:
  US14/109,840
• Publication Number:
  US 20140176495A1
• Time in Patent Office: 665 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0441 using active external devices, e.g. active pens, for receiving changes in electrical potential transmitted by the digitiser, e.g. tablet driving signals
• CPC Class Codes: G06F 3/0442 using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

Embodiments relate generally to control devices, such as human interface devices, configured for use with a touch-screen containing device. More specifically, the present invention relates to methods and various apparatus that are used to actively control the interaction of a handheld device, such as a stylus pen, with a touch-screen containing device. Embodiments of the invention provide a universal handheld device that is able to provide input to any type of capacitive sensing touch-screen containing device, regardless of the manufacturer or, in some embodiments, without knowledge of the touch-screen containing device manufacturer'"'"'s specific capacitive touch-sensing detection techniques.

Claims

1. A stylus adapted for use with a touch sensing device, comprising:

a conductive tip;

a memory unit configured to store a first data set and a second data set, wherein the first data set comprises information about a first capacitive sensing process that is performed by a first type of touch sensing device and the second data set comprises information about a second capacitive sensing process that is performed by a second type of touch sensing device;

a controller configured to compare capacitive sensing signal data received from a touch sensing device with the first data set and the second data set; and

a generator assembly configured to deliver a capacitive sensing controlling signal to the conductive tip, wherein the capacitive sensing controlling signal is derived from the comparison of the received capacitive sensing signal data with the first data set performed by the controller.

2. The stylus of claim 1, further comprising:

an amplifier having an input and an output;

a controlling capacitor coupled in series between the conductive tip and the input of the amplifier; and

two or more comparators that are coupled to the output of the amplifier,

wherein the controller is further configured to receive data from each of the two or more comparators.

3. The stylus of claim 2, further comprising a non-transitory computer-readable medium storing program instructions that, when executed by a processing unit of the stylus that is configured to interact with the touch sensing device, cause the processing unit to perform the steps of:

receiving capacitive sensing signal during a cyclical scan of a touch sensing surface performed by the touch sensing device, wherein the received capacitive sensing signal is received at a first input of the controlling capacitor;

detecting the amplitude of the received capacitive sensing signal using a detection process, wherein the detection process comprises;

(a) connecting the amplifier input side of the controlling capacitor to ground for a first period of time;

(b) disconnecting the amplifier input side of the controlling capacitor from ground for a second period of time;

(c) measuring a voltage formed on the amplifier input side of the capacitor by use of the amplifier; and

(d) repeating steps (a), (b) and (c) at least two times during a cycle of the cyclical scan process performed by the touch sensing device;

determining a time during a cycle of the cyclical scan process performed by the touch sensing device a first measured voltage is greater than a second measured voltage, wherein the first and the second measured voltages are each determined during different second periods of time during the cycle of the cyclical scan process; and

generating voltage at the conductive tip when the determined time during a cycle of the cyclical scan process occurs.

4. The stylus of claim 1, further comprising:

an amplifier having an input and an output;

a controlling capacitor coupled in series between the conductive tip and the input of the amplifier;

a drive switching device having an output connection that is electrically coupled to an electrical connection formed between the conductive tip and the controlling capacitor, and the output connection is configured to be electrically coupled to one of a plurality of connection points, wherein the plurality of connection points comprise;

a first connection point that is coupled to a resistive element that is coupled to a ground; and

a second connection point that is coupled to a first drive voltage source,

wherein the controller further comprises one or more data inputs that are configured to receive a signal delivered from the output of the amplifier.

5. A stylus adapted for use with a touch sensing device, comprising:

a conductive tip;

a memory unit configured to store a first data set, wherein the first data set comprises information relating to a capacitive sensing process that is performed by at least one type of touch sensing device;

a controller configured to compare capacitive sensing signal data received from a touch sensing device with the first data set; and

a generator assembly configured to deliver a capacitive sensing controlling signal to the conductive tip, wherein the capacitive sensing controlling signal is derived from the comparison of the received capacitive sensing signal data and the first data set performed,

wherein the memory unit is configured to store program instructions that, when executed by a processing unit of the stylus cause the processing unit to perform the steps of;

receiving the capacitive sensing signal data from the touch sensing device, wherein the received capacitive sensing signal is received during a cyclical scan of a touch sensing surface performed by the touch sensing device, and the capacitive sensing signal data comprises the first data set, which is collected over a first time interval of the cyclical scan, and a second data set collected over a second time interval of the cyclical scan;

comparing the first data set and the second data set to determine if the magnitude of the capacitive sensing signal in the first data set is different than the magnitude of the capacitive sensing signal in the second data set; and

generating a voltage at the conductive tip during the first time interval when the comparison determines that the magnitude of the capacitive sensing signal in the first data set is different than the magnitude of the capacitive sensing signal of the second data set during a previous cyclical scan.

6. A stylus adapted for use with a touch sensing device, comprising:

a conductive tip;

an amplifier having an input and an output;

a controlling capacitor coupled in series between the conductive tip and the input of the amplifier;

two or more comparators that are coupled to the output of the amplifier;

a controller configured to receive data from each of the two or more comparators; and

a switching device electrically connected between a ground and a portion of an electrical connection formed between the controlling capacitor and the input of the amplifier.

7. The stylus of claim 6, further comprising a drive switching device having an output that is electrically coupled to an electrical connection formed between the conductive tip and the controlling capacitor, wherein the drive switching device comprises:

a first connection point that is coupled to a resistive element that is coupled to a ground; and

a second connection point that is coupled to a first drive voltage source, wherein the drive switching device is configured to selectively connect the output to either the first connection point or the second connection point.

8. The stylus of claim 6, further comprising:

a voltage source coupled to the conductive tip; and

an oscillator coupled to the voltage source.

9. The stylus of claim 6, wherein the two or more comparators further comprise:

a first comparator having a first input and a second input, wherein the first input is coupled to the output of amplifier,

a second comparator having a first input and a second input, wherein the first input is coupled to the output of amplifier, and

the stylus further comprises;

a first threshold voltage source that is coupled to the second input of the first comparator; and

a second threshold voltage source that is coupled to the second input of the second comparator.

10. The stylus of claim 6, wherein a capacitive sensing signal is received by the conductive tip.

11. The stylus of claim 6, further comprising:

a memory unit configured to store a first data set, wherein the first data set comprises information relating to a capacitive sensing process that is performed by at least one type of touch sensing device, wherein the controller is further configured to compare the capacitive sensing signal with the first data set; and

a drive voltage source configured to deliver a capacitive sensing controlling signal to the conductive tip, wherein the capacitive sensing controlling signal is derived from the comparison of the received capacitive sensing signal and the first data set performed by the controller.

12. The stylus of claim 6, further comprising:

a communication unit that is configured to transmit data to the touch sensing device using a wireless communication method.

13. A stylus adapted for use with a touch sensing device, comprising:

a conductive tip;

an amplifier having an input and an output;

a controlling capacitor coupled in series between the conductive tip and the input of the amplifier;

a drive switching device having an output connection that is electrically coupled to an electrical connection formed between the conductive tip and the controlling capacitor, and the output connection is configured to be electrically coupled to one of a plurality of connection points, wherein the plurality of connection points comprise;

a first connection point that is coupled to a resistive element that is coupled to a ground; and

a second connection point that is coupled to a first drive voltage source; and

a controller having one or more data inputs that are configured to receive a signal delivered from the output of the amplifier.

14. The stylus of claim 13, further comprising an input switching device electrically connected between the ground and a portion of an electrical connection formed between the controlling capacitor and the input of the amplifier.

15. The stylus of claim 13, further comprising:

two or more comparators that are coupled to the output of amplifier and to the one or more data inputs of the controller.

16. The stylus of claim 15, wherein

the two or more comparators further comprise:

a first comparator having a first input and a second input, wherein the first input is coupled to the output of amplifier,

a second comparator having a first input and a second input, wherein the first input is coupled to the output of amplifier, and

the stylus further comprises;

a first threshold voltage source that is coupled to the second input of the first comparator; and

a second threshold voltage source that is coupled to the second input of the second comparator.

17. The stylus of claim 13, further comprising:

a memory unit configured to store a first data set, wherein the first data set comprises information relating to a capacitive sensing process that is performed by at least one type of touch sensing device, wherein the controller is further configured to compare the capacitive sensing signal with the first data set; and

a generator assembly configured to deliver a capacitive sensing controlling signal to the conductive tip, wherein the capacitive sensing controlling signal is derived from the comparison of the received capacitive sensing signal and the first data set performed by the controller.

18. The stylus of claim 13, further comprising:

a communication unit that is configured to transmit data to the touch sensing device using a wireless communication method.

19. The stylus of claim 13, further comprising a non-transitory computer-readable medium storing program instructions that, when executed by a processing unit of the stylus that is configured to interact with the touch sensing device, cause the processing unit to perform the steps of:

receiving capacitive sensing signal during a cyclical scan of a touch sensing surface performed by the touch sensing device, wherein the received capacitive sensing signal is received at a first input of the controlling capacitor;

detecting the amplitude of the received capacitive sensing signal using a detection process, wherein the detection process comprises;

(a) connecting the amplifier input side of the controlling capacitor to ground for a first period of time;

(b) disconnecting the amplifier input side of the controlling capacitor from ground for a second period of time;

(c) measuring a voltage formed on the amplifier input side of the capacitor by use of the amplifier; and

(d) repeating steps (a), (b) and (c) at least two times during a cycle of the cyclical scan process performed by the touch sensing device;

determining a time during a cycle of the cyclical scan process performed by the touch sensing device a first measured voltage is greater than a second measured voltage, wherein the first and the second measured voltages are each determined during different second periods of time during the cycle of the cyclical scan process; and

generating voltage at the conductive tip when the determined time during a cycle of the cyclical scan process occurs.