Fingerprint detection device and method and associated touch control device with fingerprint detection

• US 8,669,843 B2
• Filed: 12/23/2008
• Issued: 03/11/2014
• Est. Priority Date: 10/17/2008
• Status: Active Grant

• Current Assignee: Acer, Inc.
• Original Assignee: Acer, Inc.
• Inventors: Chen, Chih-Chiang
• Primary Examiner(s): Lee, Benjamin C
• Assistant Examiner(s): BURGDORF, STEPHEN R
• Application Number:
  US12/317,455
• Publication Number:
  US 20100098303A1
• Time in Patent Office: 1,904 Days
• Field of Search: 382/115, 382/124, 382/125, 382/103, 382/107, 382/116, 382/312, 382/313, 340/1.1, 340/2.1, 340/2.2, 340/2.21, 340/2.7, 340/5.83, 340/14.1, 340/14.2, 340/14.6, 340/5.1, 340/5.2, 340/5.51, 340/5.52, 340/5.74, 340/5.82, 340/14.61, 340 1462- 1469, 348/14.02, 463/36, 463/37, 345/164, 345/165, 345173-178, 178/18.01, 178/18.06, 178/18.11
• US Class Current: 340/5.83
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

A fingerprint detection device and method and an associated touch control device with fingerprint detection are disclosed. The fingerprint detection device includes special detecting units for upgrading the accuracy of fingerprint detection. The fingerprint detection device comprises a plurality of detecting units, a driving circuit and a reading circuit. Each detecting unit includes a fingerprint electrode and a storage capacitor coupled to the fingerprint electrode. A sense capacitor can be formed between the fingerprint electrode and a finger, where the sense capacitor is parallel connected to the storage capacitor. The driving circuit is coupled to the detecting units and provides a charging signal to charge an equivalent capacitor of each detecting unit, where the capacitance of the equivalent capacitor is determined according to whether the sense capacitor is formed within the detecting unit. The reading circuit is coupled to the detecting units and reads the voltage of the storage capacitor after the equivalent capacitor is charged, so as to determine whether the detecting unit detects a portion of fingerprint and the detected portion is a furrow or ridge.

Claims

1. A touch control device with fingerprint detection comprising:

a plurality of detecting units configured as a detecting matrix having a plurality of rows and columns, each of the detecting units comprising a fingerprint electrode, a first switch coupled to the fingerprint electrode, and a storage capacitor coupled to the fingerprint electrode;

wherein when a finger is touching one of the detecting units, a sense capacitor is formed between the fingerprint electrode of that touched detecting unit and the finger in such a manner that the sense capacitor is connected in parallel to the storage capacitor to form an equivalent capacitor;

a driving circuit, coupled to the detecting units, for providing a charging signal to charge the equivalent capacitor within each of the detecting units, wherein a capacitance of the equivalent capacitor is determined in part according to whether the sense capacitor is formed within the detecting unit;

a reading circuit, coupled to the detecting units, for reading a voltage of the equivalent capacitor of each of the detecting units after the equivalent capacitor is charged;

a selecting circuit, coupled to the detecting matrix via a plurality of control lines, each of the control lines being coupled to one row of the detecting units, for selecting each row of the detecting units in order during a write interval and a read interval respectively, wherein the write interval occurs before the read interval;

wherein, the driving circuit provides the charging signal to the selected detecting units via the first switch during the write interval, and the reading circuit reads the voltage of the equivalent capacitor of each selected detecting unit via the same first switch during the read interval; and

a switching circuit, coupled to the driving circuit and the reading circuit, for coupling to the detecting matrix via a plurality of data lines, wherein each of the data lines is coupled to one column of the detecting units;

wherein the switching circuit couples the data lines to the driving circuit during the write interval, and couples the data lines to the reading circuit during the read interval;

wherein the first switch of each of the detecting units is coupled between one of the data lines and the fingerprint electrode and receives a control signal from one of the control lines so as to control whether the first switch is closed;

wherein the first switch of the selected detecting unit is closed during the write interval such that the selected detecting unit receives the charging signal via the data line coupled to the first switch;

the first switch of the selected detecting unit is closed during the read interval such that the reading circuit performs reading via the same data line coupled to the first switch;

wherein the detecting units are configured within the detecting matrix as a fingerprint detecting area and a touch control area, and

wherein a density of the detecting units within the fingerprint detecting area is greater than the density of the detecting units within the touch control area.

2. The touch control device with fingerprint detection of claim 1, wherein each of the detecting units further comprises a second switch coupled between the fingerprint electrode and a grounded line, and the touch control device with fingerprint detection further comprises:

a resetting circuit, coupled to the detecting units, for providing a reset signal to the detecting units so as to control whether the second switch of the detecting unit is closed.

3. The touch control device with fingerprint detection of claim 2, wherein the second switch of the detecting unit is closed before the driving circuit provides the charging signal to the detecting unit or after the reading circuit reads the voltage of the equivalent capacitor of the detecting unit.

4. The touch control device with fingerprint detection of claim 1, wherein when the sense capacitor is formed within the detecting unit, the capacitance of the equivalent capacitor of the detecting unit is determined according to a sum of capacitances of both the storage capacitor and the sense capacitor.

5. A touch control with fingerprint detection method comprising steps of:

providing a touch control with fingerprint detection device comprising a plurality of detecting units, a driving circuit, a reading circuit, a selecting circuit and a switching circuit;

said plurality of detecting units being configured as a detecting matrix having a plurality of rows and columns, each of the detecting units comprising a fingerprint electrode, a first switch coupled to the fingerprint electrode, and a storage capacitor coupled to the fingerprint electrode;

wherein when a finger is touching one of the detecting units, a sense capacitor is formed between the fingerprint electrode of that touched detecting unit and the finger in such a manner that the sense capacitor is connected in parallel to the storage capacitor to form an equivalent capacitor;

said driving circuit being coupled to the detecting units;

said reading circuit being coupled to the detecting units;

said selecting circuit being coupled to the detecting matrix via a plurality of control lines, each of the control lines being coupled to one row of the detecting units;

during a write interval, said selecting circuit selecting each row of the detecting units in order, and the driving circuit providing a charging signal to charge the equivalent capacitor within each of the selected detecting units, wherein a capacitance of the equivalent capacitor is determined in part according to whether the sense capacitor is formed within the detecting unit; and

during a read interval, wherein the read interval lies after the write interval, said selecting circuit selecting each row of the detecting units in order, and said reading circuit reading a voltage of the equivalent capacitor of each of the selected detecting units after the equivalent capacitor is charged;

wherein, the driving circuit provides the charging signal to the selected detecting units via the first switch during the write interval, and the reading circuit reads the voltage of the equivalent capacitor of each selected detecting unit via the same first switch during the read interval;

wherein, said switching circuit being coupled to the driving circuit and the reading circuit for coupling to the detecting matrix via a plurality of data lines, each of the data lines is coupled to one column of the detecting units;

wherein the switching circuit couples the data lines to the driving circuit during the write interval, and couples the data lines to the reading circuit during the read interval;

wherein the first switch of each of the detecting units is coupled between one of the data lines and the fingerprint electrode and receives a control signal from one of the control lines so as to control whether the first switch is closed;

wherein the first switch of the selected detecting unit is closed during the write interval such that the selected detecting unit receives the charging signal via the data line coupled to the first switch;

wherein the first switch of the selected detecting unit is closed during the read interval such that the reading circuit performs reading via the same data line coupled to the first switch;

wherein the detecting units are configured within the detecting matrix as a fingerprint detecting area and a touch control area, and

wherein a density of the detecting units within the fingerprint detecting area is greater than the density of the detecting units within the touch control area.

6. The touch control with fingerprint detection method of claim 5,

wherein, each of the detecting units further comprises a second switch coupled between the fingerprint electrode and a grounded line, and the touch control with fingerprint detection device further comprises a resetting circuit coupled to the detecting units for providing a reset signal to the detecting units so as to control whether the second switch of the detecting unit is closed;

wherein, before charging the equivalent capacitor, said fingerprint detection method further comprises the following step;

said resetting circuit providing said reset signal to the detecting units in order to reset an voltage level of the fingerprint electrode of each of the detecting units to zero.

7. The touch control with fingerprint detection method of claim 5,

wherein, each of the detecting units further comprises second switch coupled between the fingerprint electrode and a grounded line, and the touch control with fingerprint detection device further comprises a resetting circuit coupled to the detecting units for providing a reset signal to the detecting units so as to control whether the second switch of the detecting unit is closed;

wherein, after reading the voltage of the equivalent capacitor, said touch control with fingerprint detection method further comprises the following step;

said resetting circuit providing said reset signal to the detecting units in order to reset an voltage level of the fingerprint electrode of each of the detecting units to zero.