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DE-112017006270-B4 - Capacitive scanning with multi-pattern scanning

DE112017006270B4DE 112017006270 B4DE112017006270 B4DE 112017006270B4DE-112017006270-B4

Abstract

A detection circuit (200) that includes the following: a first input which is effectively coupled to a first set of two or more transmitting electrodes (TX) (302); a first set of two or more inputs (205.1-205.N) each effectively coupled to a first set of two or more receiving electrodes (RX) (308), forming at least four intersections with the first set of two or more transmitting electrodes (302), wherein the at least four intersections comprise a first intersection and a second intersection, wherein a first number of TX electrodes in the first set of two or more TX electrodes (302) is different from a second number of RX electrodes in the first set of two or more RX electrodes (308); a second set of two or more inputs, each effectively coupled to a second set of two or more electrodes (314), thereby forming a second intersection and a third intersection with the first set of two or more TX electrodes (302); a sampling control circuit (280) that is functionally coupled to the first input, the first set of two or more inputs and the second set of two or more inputs in order to simultaneously select the first set of two or more RX electrodes (308) and simultaneously select the second set of two or more RX electrodes (314) via a multiplexer (211, 212), so that the multiplexer (212) electrically couples the first set of the two or more TX electrodes (302), so that a first signal is simultaneously applied to the two or more TX electrodes (302), and so that the multiplexer (211) couples the first set of the two or more RX electrodes (308) to simultaneously receive a second signal generated by a current produced in response to the first signal by the first set of two or more RX electrodes (308); an analog front end (AFE) (220) configured for the following: Generating a first digital value that is representative of a first counter-capacitance of a first unit cell (310), wherein the first unit cell (310) includes the first intersection and the second intersection; and generating a second digital value that is representative of a second counter-capacitance is representative of a second unit cell, wherein the second unit cell includes the second intersection and the third intersection; and a channel machine (260) that is functionally coupled to the AFE (220) that is configured to generate a first capacity value and a second capacity value corresponding to the first unit cell (310) and the second unit cell, respectively.

Inventors

  • Oleksandr Karpin
  • Mykhaylo Krekhovetskyy
  • Ruslan Omelchuk
  • ROMAN OGIRKO
  • Viktor Kremin

Assignees

  • Infineon Technologies Americas Corp.

Dates

Publication Date
20260513
Application Date
20170828
Priority Date
20170331

Claims (14)

  1. A detection circuit (200) comprising: a first input that is operatively coupled to a first set of two or more transmitting electrodes (TX) (302); a first set of two or more inputs (205.1-205.N) that are each operatively coupled to a first set of two or more receiving electrodes (RX) (308), forming at least four intersections with the first set of two or more transmitting electrodes (302), wherein the at least four intersections comprise a first intersection and a second intersection, wherein a first number of TX electrodes in the first set of two or more TX electrodes (302) is different from a second number of RX electrodes in the first set of two or more RX electrodes (308); a second set of two or more inputs, each effectively coupled to a second set of two or more electrodes (314), thereby forming a second intersection point and a third intersection point with the first set of two or more TX electrodes (302); a sampling control circuit (280) that is functionally coupled to the first input, the first set of two or more inputs, and the second set of two or more inputs to simultaneously select, via a multiplexer (211, 212), the first set of two or more RX electrodes (308) and the second set of two or more RX electrodes (314), so that the multiplexer (212) electrically couples the first set of the two or more TX electrodes (302) so that a first signal is simultaneously applied to the two or more TX electrodes (302), and so that the multiplexer (211) couples the first set of the two or more RX electrodes (308) to simultaneously receive a second signal generated by a current produced in response to the first signal by the first set of two or more RX electrodes (308); An analog front-end (AFE) (220) configured to: generate a first digital value representative of a first counter-capacitance of a first unit cell (310), the first unit cell (310) comprising the first intersection and the second intersection; and generate a second digital value representative of a second counter-capacitance of a second unit cell, the second unit cell comprising the second intersection and the third intersection; and a channel machine (260) actively coupled to the AFE (220) configured to generate a first capacitance value and a second capacitance value corresponding to the first unit cell (310) and the second unit cell, respectively.
  2. Detection circuit (200) according to Claim 1 , which further includes a fingerprint control unit (632) to detect the presence of a groove or valley of a fingerprint on a panel of electrodes (304) based on the capacitance value.
  3. Method (500) comprising: simultaneous driving (510), by a processing device, of a first set of two or more driving electrodes (TX electrodes) (402) of a touch panel of electrodes (304); simultaneous driving (515) of a second set of two or more TX electrodes (408) of the touch panel (304); simultaneous receiving (520) of two or more first signals from a first set of two or more receiving electrodes (RX electrodes) (404) of the panel of electrodes (304) in response to the simultaneous driving of the first set of two or more TX electrodes (408); Simultaneous reception (525) of two or more second signals from a second set of two or more RX electrodes (410) of the panel of electrodes (304) in response to the simultaneous driving of the second set of two or more TX electrodes (408); Determine (530), by the processing device, a first capacity for a first unit cell (406) comprising at least four intersections of the first set of two or more TX electrodes (402) and the first set of two or more RX electrodes (404); and determine (535) a second capacity for a second unit cell (412) comprising at least four intersections of the second set of two or more TX electrodes (408) and the second set of two or more RX electrodes (410), wherein the at least four intersections of the second unit cell (412) include at least two intersections of the first unit cell (406), wherein a first number of TX electrodes is different from a second number of RX electrodes of the first and second sets of the two or more RX electrodes.
  4. Procedure according to Claim 3 , which further includes: generating a first image (802) based on the first capacity; generating a second image (804) based on the second capacity; and generating a combined image (806) based on the first image (802) and the second image (804).
  5. Procedure according to Claim 4 , wherein the combined image (806) includes: an odd column of pixels containing the first capacity, and an even column containing the second capacity.
  6. Procedure according to Claim 4 , which further includes: storing the first capacity and the second capacity in a memory (262); and determining, based on the first capacity and the second capacity, the presence of a groove or valley of a fingerprint on the electrode touch panel (304).
  7. Procedure according to Claim 3 , wherein the simultaneous driving (510) of the first set of two or more TX electrodes (402) of the touch panel of electrodes (304) includes causing a multiplexer (212) coupled to the two or more TX electrodes (402) to electrically couple the two or more TX electrodes (402) to simultaneously drive a signal onto the two or more TX electrodes (402).
  8. Procedure according to Claim 3 , wherein the simultaneous reception (520) of the two or more first signals from the first set of two or more RX electrodes (404) involves a multiplexer (211) coupled to the two or more RX electrodes (404) being caused to electrically couple the two or more RX electrodes (404) in order to simultaneously receive the two or more first signals on the two or more RX electrodes (404).
  9. A touch detection system (600) comprising: a touch panel of electrodes (100) comprising: a first set of drive electrodes (TX) (106) arranged along a first axis of the touch panel (100); a first set of two or more receive electrodes (RX) (104) arranged along a second axis of the touch panel (100), wherein the first set of TX electrodes (106) and the first set of two or more RX electrodes (104) form a first intersection and a second intersection, wherein a number of TX electrodes in the first set of TX electrodes (106) is different from a second number of RX electrodes in the first set of two or more RX electrodes (104); and a second set of two or more RX electrodes arranged along the second axis of the touch panel (100), wherein the first set of TX electrodes (106) and the second set of two or more RX electrodes form the second intersection and a third intersection; a sampling control circuit (280) effectively coupled to the touch panel (100) of electrodes to simultaneously select the first set of two or more electrodes and the second set of two or more electrodes via a multiplexer (211, 212); an analog front end (AFE) (220) configured to: generate a first digital value representative of a first counter-capacitance of a first unit cell (406), wherein the first unit cell (406) includes the first intersection and the second intersection; and generating a second digital value representative of a second counter-capacitance of a second unit cell (412), wherein the second unit cell (412) includes the second intersection and the third intersection; a channel machine (260) actively coupled to the AFE (220) configured to generate a first capacitance value and a second capacitance value corresponding to the first unit cell (406) and the second unit cell (412), respectively; and a memory (262) actively coupled to the AFE (220) configured to store the To store the capacity value generated by the channel machine (260).
  10. Touch detection system according to Claim 9 , wherein, in order to select the first set of two or more RX electrodes (104) at the same time, the sampling control circuit (280) serves to: drive a first signal to a set of TX electrodes (106); and cause the multiplexer (211) to electrically couple the first set of two or more RX electrodes (104) in order to receive at the same time a second signal which is generated by a current which is induced on the first set of two or more RX electrodes (104) in response to the first signal.
  11. Touch detection system according to Claim 9 , wherein the first set of TX electrodes includes a first set of two or more driving electrodes (TX electrodes) (106), forming at least four intersection points with the first set of two or more RX electrodes (104), and wherein the sampling control circuit (280) further serves to: cause the multiplexer (212) to electrically couple the second set of two or more TX electrodes (408) to simultaneously drive a first signal onto the two or more TX electrodes (408); and cause the multiplexer (211) to electrically couple the first set of two or more RX electrodes (104) to simultaneously receive a second signal generated by a current induced on the first set of two or more RX electrodes (104) in response to the first signal.
  12. Touch detection system according to Claim 11 , wherein a first number of TX electrodes in the second set of two or more TX electrodes (408) differs from a second number of RX electrodes in the first set of two or more RX electrodes (104).
  13. Touch detection system according to Claim 11 , wherein a first number of TX electrodes in the second set of two or more TX electrodes (408) is the same as a second number of RX electrodes in the first set of two or more RX electrodes (104).
  14. Touch detection system according to Claim 9 , which further includes a fingerprint control unit (632) to detect the presence of a groove or valley of a fingerprint on the touch panel (100) made of electrodes based on the capacitance value.

Description

RELATED REGISTRATIONS This application is an international application of the US patent application. No. 15/476,217, filed on 31 March 2017, which establishes the priority of the provisional US patent application no. 62/434,099 , filed on December 14, 2016, claimed. TECHNICAL AREA This disclosure generally concerns electronic systems and specifically capacity measurement and touch detection. BACKGROUND Capacitance sensing systems can detect electrical signals generated at electrodes that reflect changes in capacitance. Such changes in capacitance can indicate the presence of ridges and valleys in a fingerprint. Touch sensing can be used for applications on a variety of user interface devices, such as mobile handsets, personal computers, and tablets. Using capacitance sensing for touch detection allows a touch sensor (also referred to herein as electrode, sensor, etc.) to be placed in or beneath the surface of a user interface device with a high degree of configurability. In a particular embodiment, a touch sensor may not need to be specific to a single location for all devices. Rather, touch sensors can be placed wherever it is practical for the industrial design of the device. Capacitance-based touch sensors operate by measuring the capacitance of a capacitive sensing element and detecting a change in capacitance, thus indicating the presence or absence of an object (e.g., a finger, a fingerprint ridge, or a valley). When an object comes into contact with or is in close proximity to a touch sensor, the change in capacitance caused by the object is detected. The capacitance change of the touch sensor can be measured by an electrical circuit and converted into digital capacitance values. Furthermore, the disclosure of the DE 10 2012 215 894 A1 and the US 2014 / 0 253 492 A1 This may be helpful for understanding the present invention. DE 10 2012 215 894 A1 This relates to a device comprising a touch sensor with a plurality of control lines. The device further comprises a computer-readable non-volatile storage medium or several computer-readable non-volatile storage media coupled to the touch sensor and comprising logic configured to, when executed, drive at least two of the control lines with one or more electrical pulses each. US 2014 / 0 253 492 A1 Disclosing a processing device, which during a first operation scans a first plurality of electrodes along a first axis in a capacitive sensor array to generate a first plurality of signals corresponding to mutual capacitance at the electrode intersection points of the capacitive sensor array. During a second operation, the processing device scans a second plurality of electrodes along a second axis in the capacitive sensor array to generate a second plurality of signals corresponding to mutual capacitance at the electrode intersection points of the capacitive sensor array, the second operation occurring during a different time period than the first operation. The processing device determines a first coordinate of a conductive object near the capacitive sensor array based on the first plurality of signals and a second coordinate of the conductive object based on the second plurality of signals. DESCRIPTION OF THE FIGURES The present revelation is illustrated by example and without limitation in the figures of the accompanying drawings. 1 illustrates a system comprising a touch detection circuit according to a single embodiment. 2 illustrates a touch detection circuit according to a single embodiment. 3A Illustrates a first multi-pattern scan of a touch detection circuit according to a single embodiment. 3B illustrates a second multi-pattern scan of a touch detection circuit according to a single embodiment. 4A illustrates a third multi-pattern scan of a touch detection circuit according to a single embodiment. 4B illustrates a fourth multi-pattern scan of a touch detection circuit according to a single embodiment. 5 illustrates a method for multi-pattern scanning according to a single embodiment. 6 illustrates a system comprising a touch sensor according to a single embodiment. 7 illustrates a method for combining multi-pattern scanning images according to a single embodiment. 8 Illustrates multi-pattern scanning images according to a single embodiment. DETAILED DESCRIPTION For explanatory purposes, numerous specific details are set forth in the following description to provide a thorough understanding of the embodiments of the present invention discussed in this patent specification. However, it will be evident to a person skilled in the art that these and other embodiments can be carried out without these specific details. In other cases, well-known structures and techniques are not shown in detail but instead in a block diagram so as not to complicate the understanding of this description. References in the description to "a single embodiment" or "an embodiment" mean that a particular feature, structure, or property described in connection with the embodiment