Latency Measurement

• US 20120191394A1
• Filed: 08/04/2011
• Published: 07/26/2012
• Est. Priority Date: 01/24/2011
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Uzelac, Aleksandar, Stevens, David A., Zhao, Weidong, Shigemitsu, Takahiro, Willoughby, Briggs A., Pierce, John Graham, Santiago, Pravin Kumar, Ranta, Craig S., Wright, Timothy Allen, Maier, Jeffrey C., Perry, Robert T., Kirilov, Stanimir Naskov
• Granted Patent: US 8,725,443 B2
• Time in Patent Office: Days
• US Class Current: 702/79
• CPC Class Codes: G06F 11/2221 to test input/output devices or peripheral units
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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

Touchscreen testing techniques are described. In one or more implementations, a piece of conductor (e.g., metal) is positioned as proximal to a touchscreen device and the touchscreen device is tested by simulating a touch of a user. This technique may be utilized to perform a variety of different testing of a touchscreen device, such as to test latency and probabilistic latency. Additional techniques are also described including contact geometry testing techniques.

Claims

1. A method implemented by one or more computing devices, the method comprising:

measuring a time delay of a touchscreen device to evaluate a touch input by;

placing a conductor that is disposed proximal to the touchscreen device in a grounded state;

receiving a report from the touchscreen device indicating a point in time at which the touch input was detected by the touchscreen device; and

computing the time delay by comparing the point in time at which the touch input was detected by the touchscreen device with a point in time at which the conductor was placed in the grounded state.

2. A method as described in claim 1, further comprising synchronizing a clock on the one or more computing devices that is utilized to indicate the point in time at which the conductor was placed in the grounded state with a clock of the touchscreen device that is utilized to indicate the point in time at which the touch input was detected by the touchscreen device.

3. A method as described in claim 1, wherein the placing is performed using an electrical switch driven by the one or more computing devices.

4. A method as described in claim 1, wherein the placing of the conductor in the grounded state emulates a touch by a user and further comprising placing the conductor in an ungrounded state while the conductor is still disposed proximal to the digitizer to emulate a lack of the touch input on the computing device.

5. A method as described in claim 4, wherein the placing of the conductor in the grounded state, the receiving of the report, the computing of the time delay, and the placing of the conductor in an ungrounded state are performed a plurality of times to generate an overall measurement of the time delay of the touchscreen device.

6. A method as described in claim 4, wherein the placing of the conductor in the grounded state, the receiving of the report, the computing of the time delay, and the placing of the conductor in an ungrounded state are performed for a plurality of different locations on the touchscreen device.

7. A method as described in claim 1, further comprising placing the conductor in an ungrounded state to emulate a lack of the touch input on the computing device and computing a time delay of the touchscreen device to detect lack of the touch input.

8. A method as described in claim 7, wherein the placing of the conductor in the grounded and ungrounded states is performed without moving the conductor from its position as proximal to the touchscreen device.

9. An apparatus comprising:

a clock;

a conductor configured to be disposed proximally to a touchscreen device;

an electrical switch that is electrically coupled to the conductor; and

one or more modules communicatively coupled to the electrical switch and the clock, the one or more modules configured to;

cause the electrical switch to place the conductor in a grounded state when disposed proximally to the touchscreen device to emulate a touch input;

record a point in time from the clock at which the causing occurred; and

compute a latency of the touchscreen device to detect the touch input by comparing a point in time at which the touch input was detected by the touchscreen device with the recorded point in time.

10. An apparatus as described in claim 9, wherein the point in time at which the touch input was detected by the touchscreen device is received at the apparatus via a report from the touchscreen device.

11. An apparatus as described in claim 9, wherein the one or more modules are further configured to synchronize the clock with a clock of the touchscreen device that is utilized to indicate the point in time at which the touch input was detected by the touchscreen device.

12. An apparatus as described in claim 9, wherein the placement of the conductor in the grounded state emulates a touch by a user and placement of the conductor in an ungrounded state emulates a lack of the touch input on the computing device.

13. An apparatus as described in claim 12, wherein the placement of the conductor in the grounded state, the recordation of the point in time from the clock, and the computation of the latency are performed for plurality of times to generate an overall measurement of the time delay of the touchscreen device.

14. An apparatus as described in claim 9, wherein the placement of the conductor in the grounded state, the recordation of the point in time from the clock, and the computation of the latency are performed for a plurality of different locations on the touchscreen device.

15. An apparatus as described in claim 9, wherein the one or more modules are further configured to cause the switch to place the conductor in an ungrounded state to emulate a lack of the touch input and compute a time delay of the touchscreen device to detect the lack of the touch input.

16. An apparatus as described in claim 15, wherein the placing of the conductor in the grounded and ungrounded states is performed without moving the conductor from a position as proximal to the touchscreen device.

17. A method implemented by one or more computing devices, the method comprising:

measuring a time delay of a touchscreen device to evaluate lack of a touch input by;

placing a conductor that is disposed proximal to the touchscreen device in a ungrounded state from a grounded state;

receiving a report from the touchscreen device indicating a point in time at which the lack of the touch input was detected by the touchscreen device; and

computing the time delay by comparing the point in time at which the lack of the touch input was detected by the touchscreen device with a point in time at which the conductor was placed in the ungrounded state.

18. A method as described in claim 17, wherein the placing is performed using an electrical switch driven by the one or more computing devices.

19. A method as described in claim 17, wherein the placing of the conductor is performed while the conductor remains proximal to the touchscreen device.

20. A method as described in claim 17, wherein the touchscreen device employs capacitive sensors to detect the touch input.