Patent Description:
At present, a capacitive inductive fingerprint detection apparatus has been used in a new generation of electronic devices. The fingerprint detection apparatus comprises a fingerprint detection array. The fingerprint detection array performs full-array scanning according to a predetermined frequency to acquire fingerprint data, and accordingly determines whether a finger touches the fingerprint detection apparatus. When it is determined that a finger touches the fingerprint detection apparatus, a fingerprint image is formed. This manner requires that the fingerprint detection array constantly stays in an operating state of full-array scanning. As a result, the power consumption of the entire fingerprint detection apparatus is high. <CIT> recites a capacitive touchscreen or touch panel having dual finger or hand navigation and fingerprint reading capabilities. Fingerprints are read and processed by the same capacitive touchscreen controller that reads and processes capacitively-sensed finger or hand touches made across the touchscreen or touch panel. A small portion of the capacitive touchscreen or touch panel is dedicated to reading an authorized user's fingerprints, while a larger or main portion of the capacitive touchscreen or touch panel is dedicated to sensing a user's finger or hand navigation across the touchscreen or touch panel. <CIT> recites a detecting device includes: multiple sensors composed with a plurality of sensor circuits arrayed on a plane, each of which generates at least one detected signal that corresponds to a distance from a surface of an object; a selector circuit which selects each of the sensor circuits and outputs the detected signal from each of the sensor circuits; a storage which stores digital data of a reference value; a digital-to-analog converter circuit which generates a reference signal that corresponds to a level of the reference value from the digital data stored in the storage; a generation circuit which generates, per each of the sensor circuits, in sequence, detected data according to a relationship of levels between the detected signal output from each of the sensor circuits selected by the selector circuit, and the reference signal generated by the digital-to-analog converter circuit; an arithmetic circuit which conducts a prescribed operation with a plurality of detected data sets generated by the generation circuit; a refresh circuit which refreshes the digital data stored in the storage, based on an operational value calculated by the arithmetic circuit; and an output circuit which conducts an output process, corresponding to the detected data generated by the generation circuit.

The present invention is intended to solve at least one of the above technical problems.

To this end, a first objective of the present invention is to provide a detection method for fingerprint detection. With the method, a fingerprint detection array is initiated for full-array scanning upon reliable and effective identification that a finger touches a fingerprint detection apparatus, which greatly reduces the power consumption of the fingerprint detection.

To achieve the above objective, a first aspect of embodiments of the present invention provides a detection method for a fingerprint detection apparatus to perform fingerprint detection, the fingerprint detection apparatus comprises a capacitance detection module, a detection electrode, a controller and a fingerprint detection array comprising a plurality of detection units arranged in an array, each of the detection units forms a fingerprint capacitance with a finger; a first parasitic capacitance is formed between the detection electrode and a system ground; the method comprises: S1. detecting, by the capacitance detection module, a capacitance on the detection electrode when a finger of a user touches the detection electrode, the capacitance on the detection electrode is a sum of C<NUM> and C<NUM>, the C<NUM> is a parasitic capacitance between the detection electrode and a system ground, and the C<NUM> is a parasitic capacitance between the finger and the system ground and is connected in parallel to the parasitic capacitance C<NUM>; S2: initiating a part of the detection units of the fingerprint detection array to perform a fingerprint pre-detection to detect fingerprint of the finger when the controller determines that the capacitance on the detection electrode exceeds a predetermined capacitance threshold, and acquiring pre-detection fingerprint capacitance of the fingerprint pre-detection; S3:initiating all the detection units of the fingerprint detection array to perform fingerprint scanning to detect the fingerprint of the finger when the pre-detection fingerprint capacitance exceeds a first predetermined threshold;
wherein when the all the detection units of the fingerprint detection array scans the
fingerprint, the method further comprises:.

With the detection method for fingerprint detection in the embodiments of the present invention, firstly whether a capacitance on a detection electrode exceeds a predetermined capacitance threshold is determined, and when the capacitance exceeds the predetermined capacitance threshold, a part of detection units of a fingerprint detection array are initiated to perform fingerprint pre-detection and acquire pre-detection fingerprint capacitance; and whether the pre-detection fingerprint capacitance exceeds a first predetermined threshold is determined, and when the pre-detection fingerprint capacitance exceeds the first predetermined threshold, all the detection units of the fingerprint detection array are initiated to perform fingerprint scanning. In this way, the fingerprint detection array is initiated for full-array scanning upon reliable and effective identification that a finger touches a fingerprint detection apparatus, which greatly reduces the power consumption of the fingerprint detection.

A second objective of the present invention is to provide a detection apparatus for fingerprint detection.

To achieve the above objective, a second aspect of embodiments of the present invention provides a detection apparatus for fingerprint detection, comprising: a capacitance detection module, a detection electrode, a controller and a fingerprint detection array comprising a plurality of detection units arranged in an array, each of the detection units forms a fingerprint capacitance with a finger; the capacitance detection module is configured to detect a capacitance on the detection electrode when a finger of a user touches the detection electrode, wherein the capacitance on the detection electrode is a sum of C<NUM> and C<NUM>, the C<NUM> is a parasitic capacitance between the detection electrode and a system ground, and the C<NUM> is a parasitic capacitance between the finger and the system ground and is connected in parallel to the parasitic capacitance C<NUM>;.

With the detection apparatus for fingerprint detection in the embodiments of the present invention, firstly whether a capacitance on a detection electrode exceeds a predetermined capacitance threshold is determined, and when the capacitance exceeds the predetermined capacitance threshold, a part of detection units of a fingerprint detection array are initiated to perform fingerprint pre-detection and acquire pre-detection fingerprint capacitance; and whether the pre-detection fingerprint capacitance exceeds a first predetermined threshold is determined, and when the pre-detection fingerprint capacitance exceeds the first predetermined threshold, all the detection units of the fingerprint detection array are initiated to perform fingerprint scanning. In this way, the fingerprint detection array is initiated for full-array scanning upon reliable and effective identification that a finger touches a fingerprint detection apparatus, which greatly reduces the power consumption of the fingerprint detection.

The additional aspects and advantages of the present invention are partially provided in the following description, and the other portions would become more obvious from the following description or would be known from the practice of the present invention.

The above described and/or additional aspects and advantages of the present invention would be obvious and simple to understand with reference to the description of the embodiments in combination with the accompanying drawings.

It should be noted that terms such as "first", "second" and the like are merely used for illustration purpose during the description of the present invention, and shall not be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise specified and defined, the terms "coupled" and "connected" and derivative forms of these words shall be understood in a broad sense, which, for example, is understood as fixed connection, detachable connection or integral connection; is mechanically connected or electrically connected; or is directly connected, indirectly connected via an intermediate medium. Persons of ordinary skill in the art understand the specific meanings of the above terms in the present invention according to the actual circumstances and contexts. In addition, during the description of the present invention, the term "multiple", "more" or "a plurality of" refers to at least two unless otherwise specified.

Any process or method description illustrated in the flowcharts or described herein in any manner is understood as including one or a plurality of modules, segments or portions of codes of executable instructions for implementing specific logic functions or steps in the processes. In addition, the scope of the preferred embodiments of the present invention covers other implementations. The implementation of the functions or steps are not subjected to the illustrated or discussed sequence; however, the functions are implemented in a substantially simultaneous manner or in a contrary sequence according to the involved functions, which shall be understood by a person skilled in the art according to the embodiments of the present invention.

A detection method and apparatus for fingerprint detection according to embodiments of the present invention are described herein with reference to the attached drawings.

<FIG> is a flowchart of a detection method for fingerprint detection according to an embodiment of the present invention, and <FIG> is a schematic diagram of a capacitance change on a detection electrode when a finger touches the detection electrode according to an embodiment of the present invention. As illustrated in <FIG>, the detection method for fingerprint detection comprises:.

To be specific, a predetermined capacitance threshold CTH is predefined in the fingerprint detection apparatus. If it is determined that the capacitance C<NUM>+C<NUM> on the detection electrode is greater than the predetermined capacitance threshold CTH, that is, a finger touches the detection electrode, the fingerprint detection apparatus enters a second operating mode, that is, the fingerprint pre-detection mode.

However, the parasitic capacitances C<NUM> between the detection electrode B and the system ground varies in different fingerprint detection apparatuses, and the capacitance C<NUM> between the finger and the system ground is subjected to a great change due to different touch manners of the finger. Therefore, in different application environments, an error occurs when whether the finger touches the detection electrode is determined only by using the predetermined capacitance threshold CTH. In this case, the fingerprint detection apparatus needs to enter the fingerprint pre-detection mode for a further determination. As such, both reliability and accuracy of finger touch detection are improved.

In another embodiment of the present invention, if it is determined that the capacitance C<NUM>+C<NUM> on the detection electrode does not exceed the predetermined capacitance threshold CTH, the fingerprint detection apparatus keep staying in the capacitance detection mode. That is, the fingerprint detection apparatus repeatedly detects the capacitance C<NUM>+C<NUM> on the detection electrode, and determines whether the capacitance C<NUM>+C<NUM> on the detection electrode exceeds the predetermined capacitance threshold CTH.

After the fingerprint detection apparatus enters the fingerprint pre-detection mode, a part of detection units of the fingerprint detection array are initiated to perform fingerprint pre-detection. A part of detection units is one detection unit or several detection units of the fingerprint detection array. In the embodiments of the present invention, only a part of detection units of the fingerprint detection array are used for fingerprint pre-detection, instead of all the detection units of the fingerprint detection array are used for performing the fingerprint pre-detection, which greatly reduces the power consumption of the fingerprint detection apparatus. Upon the fingerprint pre-detection, the fingerprint detection apparatus acquires the pre-detection fingerprint capacitance Data<NUM> of the fingerprint pre-detection.

S103: When the pre-detection fingerprint capacitance exceeds a first predetermined threshold, all the detection units of the fingerprint detection array are initiated to perform fingerprint scanning.

To be specific, if it is determined that the pre-detection fingerprint capacitance Data<NUM> of the fingerprint pre-detection is greater than a first predetermined threshold DataTH, the fingerprint detection apparatus enters a third operating mode, that is, the fingerprint scanning mode. In this case, all the detection units of the fingerprint detection array are initiated to perform fingerprint scanning. The first predetermined threshold DataTH is predefined in the fingerprint detection apparatus.

When the detection electrode is not touched by a finger, the pre-detection fingerprint capacitance of the fingerprint pre-detection acquired by the fingerprint detection apparatus is Data<NUM>; when the detection electrode is touched by a finger, the pre-detection fingerprint capacitance of the fingerprint pre-detection acquired by the fingerprint detection apparatus is Data<NUM>. Since if the detection electrode is not touched by a finger, the pre-detection fingerprint capacitance Data<NUM> is almost <NUM>, as long as the pre-detection fingerprint capacitance Data<NUM> is great enough when a finger touches the detection electrode, a sufficiently wide range is available for defining the first predetermined threshold DataTH, such that whether a finger touches the detection electrode is further determined.

Upon double confirmation of the capacitance detection mode and the fingerprint pre-detection mode, the fingerprint detection apparatus enters the fingerprint scanning mode to initiate all the detection units of the array to perform fingerprint scanning. As such, both reliability and accuracy of the finger touch detection are improved.

After the fingerprint detection apparatus enters the fingerprint scanning mode, all the detection units of the fingerprint detection array are initiated to perform the fingerprint scanning. It should be understood that initiating all the detection units is not limited to the case where all the detection units are initiated to simultaneously perform fingerprint scanning, which is a case where all the detection units stay in an operating state of the fingerprint scanning. An internal drive circuit of the fingerprint detection apparatus performs time-sharing driving for the fingerprint detection array based on row/column of the detection units, and the detection units perform fingerprint scanning in sequence to acquire fingerprint data of the entire array, that is, one frame of the fingerprint data. The fingerprint scanning is implemented by the fingerprint detection apparatus in a conventional manner, which is not described herein any further.

In another embodiment of the present invention, if it is determined that the pre-detection fingerprint capacitance Data<NUM> does not exceed the first predetermined threshold DataTH, the fingerprint detection apparatus returns to the capacitance detection mode. That is, the fingerprint detection apparatus redetects the capacitance on the detection electrode, and determines whether the capacitance exceeds the predetermined capacitance threshold CTH.

In still another embodiment of the present invention, the fingerprint detection apparatus further determines whether the number of frames acquired in the fingerprint scanning mode reaches a second predetermined threshold, and if the number of frames in the fingerprint scanning reaches the second predetermined threshold, the fingerprint detection apparatus returns to the capacitance detection mode. In other words, upon completion of acquiring a predetermined number of frames in the fingerprint scanning, the fingerprint detection apparatus returns to the capacitance detection mode. If the number of frames in the fingerprint scanning does not reach the second predetermined threshold, the fingerprint detection apparatus continuously performs fingerprint scanning.

An operating mode transition diagram of the above fingerprint identification apparatus is as illustrated in <FIG>.

The advantages of the detection method for fingerprint detection according to the embodiments of the present invention are described hereinafter by using a specific example.

As illustrated in <FIG>, an operating current IA of a capacitance detection apparatus in a capacitance detection mode is <NUM> uA, an operating current IB of the capacitance detection apparatus in a fingerprint pre-detection mode is <NUM> mA, and an operating current Ic of the capacitance detection apparatus in a fingerprint scanning mode is <NUM> mA. In the meantime, assume that, during operation, the capacitance detection is effectively triggered at an interval of TA <NUM>, and an operating period of the fingerprint detection TB is <NUM>. As such, an average power consumption during a detection period in which the fingerprint detection apparatus detects that a finger touches the fingerprint detection apparatus is: (IA*TA+IB*TB)/(TA+TB)=<NUM> uA. Therefore, it can be seen that the average power consumption is far less than the operating current <NUM> mA during the fingerprint scanning.

With the detection method for fingerprint detection in the embodiments of the present invention, firstly determine whether a capacitance on a detection electrode exceeds a predetermined capacitance threshold, and when the capacitance exceeds the predetermined capacitance threshold, a part of detection units of a fingerprint detection array are initiated to perform fingerprint pre-detection and acquire pre-detection fingerprint capacitance; and secondly determine whether the pre-detection fingerprint capacitance exceeds a first predetermined threshold, and when the pre-detection fingerprint capacitance exceeds a first predetermined threshold, all the detection units of the fingerprint detection array are initiated to perform fingerprint scanning. In this way, the fingerprint detection array is initiated for full-array scanning upon reliable and effective identification that a finger touches a fingerprint detection apparatus, which greatly reduces the power consumption of the fingerprint detection.

<FIG> is a structural schematic diagram of a detection apparatus for finger detection according to an embodiment of the present invention. The detection apparatus comprises: a capacitance detection module <NUM>, a detection electrode <NUM>, a controller <NUM> and a fingerprint detection array <NUM>.

The capacitance detection module <NUM> detects a capacitance on the detection electrode <NUM>, and sends a detection result to the controller <NUM>. To be specific, when the fingerprint identification apparatus is in a first operating mode, that is, in a capacitance detection mode, the capacitance detection module <NUM> detects changes of the external capacitance of the fingerprint detection apparatus. A parasitic capacitance between the detection electrode <NUM> and a system ground is C<NUM>. When a finger of a user touches the detection electrode <NUM>, a capacitance between the finger and the system ground is C<NUM>, that is, the capacitance C<NUM> between the finger and the system ground is connected in parallel to the parasitic capacitance C<NUM>. To be specific, when a finger touches the detection electrode <NUM>, the capacitance on the detection electrode <NUM> should be C<NUM>+C<NUM>.

When the capacitance on the detection electrode <NUM> exceeds a predetermined capacitance threshold, the controller <NUM> controls the fingerprint detection array <NUM> to perform fingerprint pre-detection.

Upon receiving a fingerprint pre-detection command from the controller <NUM>, the fingerprint detection array <NUM> initiates a part of detection units to perform the fingerprint pre-detection, and acquires first pre-detection fingerprint capacitance. To be specific, a predetermined capacitance threshold CTH is predefined in the fingerprint detection apparatus. The capacitance detection module <NUM> feeds back the detected capacitance to the controller <NUM>, and the controller <NUM> performs a next determination. If it is determined that the capacitance is greater than the predetermined capacitance threshold CTH, the controller <NUM> controls the fingerprint detection array <NUM> to enter a second operating mode, that is a fingerprint pre-detection mode.

Furthermore, a parasitic capacitance C<NUM> between the detection electrode <NUM> and a system ground varies in different fingerprint detection apparatuses, and the capacitance C<NUM> between the finger and the system ground is subjected to a great change due to different touch manners of the finger. Therefore, in different application environments, an error occurs when whether the finger touches the detection electrode <NUM> is determined by the controller <NUM> only by using the predetermined capacitance threshold CTH. In this case, the fingerprint detection apparatus needs to enter the fingerprint pre-detection mode for a further determination. As such, both reliability and accuracy of finger touch detection are improved.

In another embodiment of the present invention, if the capacitance detected by the capacitance detection module <NUM> does not exceed the predetermined capacitance threshold, the capacitance detection module <NUM> continues detecting the capacitance on the detection electrode <NUM>. To be specific, if the controller <NUM> determines that the capacitance C<NUM>+C<NUM> on the detection electrode <NUM> does not exceed the predetermined capacitance threshold CTH, the controller <NUM> controls the capacitance detection module <NUM> to keep staying in the capacitance detection mode. That is, the capacitance detection module <NUM> repeatedly detects the capacitance CO+C1 on the detection electrode <NUM>.

After the fingerprint detection array <NUM> enters the fingerprint pre-detection mode, a part of detection units of the fingerprint detection array <NUM> are initiated to perform fingerprint pre-detection. The part of detection units refers to a single detection unit or several detection units of the fingerprint detection array <NUM>. It should be understood that in the embodiments of the present invention, only a part of detection units of the fingerprint detection array <NUM> are used for fingerprint pre-detection, rather than all the detection units of the array are used for performing fingerprint pre-detection, which greatly reduces the power consumption of the fingerprint detection apparatus. After performing the fingerprint pre-detection and acquiring pre-detection fingerprint capacitance Data1, the fingerprint detection array <NUM> sends the pre-detection fingerprint capacitance to the controller <NUM>.

When the pre-detection fingerprint capacitance exceeds a first predetermined threshold, the controller <NUM> controls the fingerprint detection array <NUM> to perform fingerprint scanning. To be specific, the fingerprint detection array <NUM> feeds back the acquired pre-detection fingerprint capacitance Data1 of the fingerprint pre-detection to the controller <NUM>, and the controller <NUM> performs a next determination. If the controller <NUM> determines that the pre-detection fingerprint capacitance Data1 is greater than the first predetermined threshold DataTH, the controller <NUM> controls the fingerprint detection array <NUM> to enter a third operating mode, that is, a fingerprint scanning mode. The first predetermined threshold DataTH is predefined in the fingerprint detection apparatus.

In other words, if the fingerprint detection array <NUM> is not touched by a finger, the pre-detection fingerprint capacitance acquired by the fingerprint detection array <NUM> is Data<NUM>; if the fingerprint detection array <NUM> is touched by a finger, the pre-detection fingerprint capacitance acquired by the fingerprint detection array <NUM> is Data<NUM>. Since if the fingerprint detection array <NUM> is not touched by a finger, the pre-detection fingerprint capacitance Data<NUM> of the fingerprint pre-detection is almost <NUM>, as long as the pre-detection fingerprint capacitance Data<NUM> is great enough when a finger touches the fingerprint detection array <NUM>, a sufficiently wide range is available for defining the first predetermined threshold DataTH, such that whether a finger touches the fingerprint detection apparatus is further determined.

Upon double confirmation of the capacitance detection mode and the fingerprint pre-detection mode, the fingerprint detection apparatus enters the fingerprint scanning mode to perform fingerprint scanning using all the detection units of the array. As such, both reliability and accuracy of the finger touch detection are improved.

After the fingerprint detection apparatus enters the fingerprint scanning mode, all the detection units of the fingerprint detection array <NUM> are initiated to perform fingerprint scanning. The fingerprint scanning is implemented by the fingerprint detection apparatus in a conventional manner, which is not described herein any further.

In another embodiment of the present invention, if the detected pre-detection fingerprint capacitance does not exceed the first predetermined threshold DataTH, the controller <NUM> controls the capacitance detection module <NUM> to return to the capacitance detection mode, that is, the capacitance detection module <NUM> redetects the capacitance C<NUM>+C<NUM>.

In still another embodiment of the present invention, the controller <NUM> determines whether the number of frames acquired in the fingerprint scanning reaches a second predetermined threshold, and if the number of frames reaches the second predetermined threshold, the controller <NUM> controls the capacitance detection module <NUM> to return to the capacitance detection mode. In other words, upon completion of acquiring a predetermined number of frames in the fingerprint scanning, the fingerprint detection apparatus returns to the capacitance detection mode.

With the detection apparatus for fingerprint detection in the embodiments of the present invention, firstly whether a capacitance on a detection electrode exceeds a predetermined capacitance threshold is determined, and when the capacitance exceeds the predetermined capacitance threshold, a part of detection units of a fingerprint detection array are initiated to perform fingerprint pre-detection and acquire pre-detection fingerprint capacitance; and secondly whether the pre-detection fingerprint capacitance exceeds a first predetermined threshold is determined, and when the pre-detection fingerprint capacitance exceeds a first predetermined threshold, all the detection units of the fingerprint detection array are initiated to perform fingerprint scanning. In this way, the fingerprint detection array is initiated for full-array scanning upon reliable and effective identification that a finger touches a fingerprint detection apparatus, which greatly reduces the power consumption of the fingerprint detection.

It should be understood that each part of the present invention is implemented by using hardware, software, firmware or a combination of them. In the above embodiments, the multiple steps or methods is implemented by using software or firmware which is stored in a memory and executed by a suitable instruction execution system. For example, if the multiple steps or methods are implemented by using hardware, similar to another embodiment, the steps or methods are implemented by using any one or a combination of the following technologies that are commonly known in the art: a discrete logic circuit of a logic gate circuit configured to implement logic function to data signals, an application specific integrated circuit having a suitable combinational logic gate, a programmable gate array (PGA), a field-programmable gate array (FPGA), and the like.

In the description of the present specification, reference terms such as "an embodiment", "some embodiments", "examples", "specific examples", "some examples", or the like are intended to refer to that the specific features, structures, materials, or characteristics which are described in combination with the embodiments or examples are comprised in at least one embodiment or example of the present invention. In this specification, schematic expressions of the above terms do not necessarily indicate the same embodiments or examples. In addition, the described specific features, structures, materials, or characteristics are combined in any one or multiple embodiments or examples in a suitable way.

Claim 1:
A detection method for a fingerprint detection apparatus to perform fingerprint detection, wherein the fingerprint detection apparatus comprises a capacitance detection module (<NUM>), a detection electrode (<NUM>), a controller (<NUM>) and a fingerprint detection array (<NUM>) comprising a plurality of detection units arranged in an array, each of the detection units forms a fingerprint capacitance with a finger;
characterized in that the method comprises:
S1: detecting (S101), by the capacitance detection module (<NUM>), a capacitance on the detection electrode (<NUM>) when a finger of a user touches the detection electrode (<NUM>), wherein the capacitance on the detection electrode is a sum of C<NUM> and C<NUM>, the C<NUM> is a parasitic capacitance between the detection electrode (<NUM>) and a system ground, and the C<NUM> is a parasitic capacitance between the finger and the system ground and is connected in parallel to the parasitic capacitance C<NUM>;
S2: initiating (S102) a part of the detection units of the fingerprint detection array (<NUM>) to perform a fingerprint pre-detection to detect a fingerprint of the finger when the controller (<NUM>) determines that the capacitance on the detection electrode (<NUM>) exceeds a predetermined capacitance threshold, and acquiring pre-detection fingerprint capacitance of the fingerprint pre-detection;
S3: initiating (S103) all the detection units of the fingerprint detection array (<NUM>), to perform fingerprint scanning to detect the fingerprint of the finger when the pre-detection fingerprint capacitance exceeds a first predetermined threshold;
wherein when the all the detection units of the fingerprint detection array (<NUM>) scans the fingerprint, the method further comprises:
determining whether the number of frames in the fingerprint scanning reaches a second predetermined threshold, wherein the all detection units perform the fingerprint scanning in sequence to acquire fingerprint data of the entire array, and the fingerprint data of the entire array is one frame;
returning to step S1, when the number of frames reaches the second predetermined threshold; and
continuously performing the fingerprint scanning when the number of frames in the fingerprint scanning does not reach the second predetermined threshold.