CN103927468B - Fingerprint identification module and display device - Google Patents

Abstract

Embodiments of the present invention provide a fingerprint identification module and a display device to solve the problems of low integration and high production cost of the fingerprint identification module in the prior art. The fingerprint recognition module includes: a flexible circuit board FPC; a fingerprint sensing circuit arranged on the flexible circuit board, including mutually insulated driving electrodes and sensing electrodes, wherein the driving electrodes extend along a first direction, and the sensing electrodes The electrodes extend along the second direction. The display device includes a display panel, an FPC of the display panel for providing electrical signals to the display panel, and the display device also includes a fingerprint recognition module.

Description

A fingerprint identification module and display device

technical field

The invention relates to the field of electronic technology, in particular to a fingerprint identification module and a display device.

Background technique

In recent years, due to the increasing demand for confidentiality of personal information, and the diversification of methods for criminals to steal data, for electronic products used in daily life, such as personal computers (PCs), personal digital assistants (PDAs) , or portable hard disk, etc., even if the electronic product falls into the hands of others, it is necessary to develop a technology that can still prevent the personal data information recorded in it from being leaked.

Most of the passwords used for protection initially consist of letters, numbers or combinations thereof entered by the user. If you want to improve the security of the protection, you need to increase the length of the password; however, the user is likely to forget the password that is too long and Complicated passwords are very inconvenient when accessing data is urgently needed. If the user uses multiple different passwords, how to remember the different passwords correctly will become a big problem. In view of the above problems, the emerging protection technology is biometric technology, because different biological individuals will have different biological characteristics, and the biological characteristics are difficult to be copied and stolen by others, such as fingerprints, voices or irises. Therefore, technologies that use biological characteristics as a distinguishing identity, such as fingerprint recognition systems, voiceprint recognition systems, and iris recognition systems, have gradually become the mainstream of emerging protection technologies.

With the development of fingerprint identification technology, fingerprint identification systems are more and more used in daily life, such as fingerprint identification access control systems, laptops with fingerprint identification systems, etc. Among them, the collection method of the sliding fingerprint sensor is to detect the fingerprint by sliding the finger on the surface of the strip sensor. Because the sliding fingerprint sensor has the advantages of small size, low power consumption and low price, it is widely used in mobile phones, smart phones, PDAs and For mobile storage devices, the production of fingerprint sensors in the prior art requires a separate production process, and the integration level is not high, which makes the production process of devices equipped with fingerprint sensors more complicated and the production cost is higher.

Contents of the invention

In view of this, the embodiment of the present invention provides a fingerprint identification module and a display device.

An embodiment of the present invention provides a fingerprint identification module, the fingerprint identification module includes:

Flexible circuit board FPC;

The fingerprint sensing circuit arranged on the flexible circuit board includes driving electrodes and sensing electrodes insulated from each other, wherein the driving electrodes extend along a first direction, and the sensing electrodes extend along a second direction.

In the fingerprint recognition module, the fingerprint sensing circuit includes a driving electrode extending along a first direction and a sensing electrode extending along a second direction; when electrified, the sensing electrode and the driving electrode form a capacitance at the intersection point, and when the finger is placed When on the fingerprint identification module, the capacitance between the sensing electrode and the driving electrode changes, and the fingerprint of the finger is identified by detecting the change of the capacitance; by setting the driving electrode extending along the first direction and the The sensing electrodes extending in the second direction increase the number of detection points in the fingerprint identification module and improve the accuracy of the detected fingerprint pattern; at the same time, the fingerprint sensing circuit is arranged on the flexible circuit board to improve the integration of the fingerprint identification module degree, while reducing production costs.

An embodiment of the present invention provides a display device. The display device includes a display panel, an FPC of the display panel for providing electrical signals to the display panel, and the display device further includes the above-mentioned fingerprint recognition module.

The display device is provided with a fingerprint identification module, and the fingerprint sensing circuit of the fingerprint identification module includes driving electrodes extending along the first direction and sensing electrodes extending along the second direction; when electrified, the sensing electrodes and driving electrodes are Intersections form capacitance. When a finger is placed on the fingerprint recognition module, the capacitance between the sensing electrode and the driving electrode changes, and the fingerprint of the finger is identified by detecting the change of the capacitance; The driving electrodes extending in one direction and the sensing electrodes extending in the second direction increase the number of detection points in the fingerprint identification module and improve the accuracy of the detected fingerprint pattern; meanwhile, the fingerprint sensing circuit is arranged on the flexible circuit board , the integration degree of the fingerprint identification module is improved, and the production cost is reduced at the same time.

Description of drawings

FIG. 1 is a schematic diagram of a fingerprint identification module provided by an embodiment of the present invention;

Figure 2 is a schematic diagram of the positions of the flexible circuit board FPC, sensing electrodes, and driving electrodes provided by the embodiment of the present invention;

Fig. 3 is a schematic diagram of the positions of another flexible circuit board FPC, sensing electrodes, and driving electrodes provided by the embodiment of the present invention;

Fig. 4 is a schematic diagram of a sensing sub-electrode and a driving sub-electrode provided by an embodiment of the present invention;

Fig. 5 is an enlarged schematic diagram of a sensing sub-electrode and a driving sub-electrode provided by an embodiment of the present invention;

FIG. 6 is a schematic flowchart of fingerprint image generation and matching provided by an embodiment of the present invention.

detailed description

Embodiments of the present invention provide a fingerprint identification module and a display device to solve the problems of low integration and high production cost of the fingerprint identification module in the prior art.

In the prior art, the fingerprint identification system includes a fingerprint sensor and a drive circuit unit, wherein: the fingerprint sensor is used to detect the current user fingerprint pattern of the fingerprint, and converts the current user fingerprint pattern into fingerprint information of an electrical signal; the drive circuit unit includes The driver chip is used to drive the fingerprint sensor and process fingerprint information detected by the fingerprint sensor.

In practical applications, the fingerprint sensor is usually designed as a long strip. Therefore, the prior art usually only includes sensing electrodes extending along the strip direction, and detects the current user by detecting changes in electrical signals on the sensing electrodes. fingerprint pattern. However, in this solution, the fingerprint sensor can only detect the pattern of the finger along the direction perpendicular to the strip, so the resolution of the obtained finger pattern is relatively low.

Meanwhile, as an independent device, the fingerprint sensor is usually fabricated on a printed circuit board, and then connected to the main board through a flexible circuit board. Therefore, the manufacturing of the fingerprint sensor in the prior art requires a separate manufacturing process, and the integration degree is not high, which further makes the manufacturing process of the device provided with the fingerprint sensor more complicated and the production cost is higher.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention.

Embodiment 1 of the present invention provides a fingerprint recognition module 10, as shown in FIG. 1; it can be seen from FIG. The sensing circuit 12 and the fingerprint identification chip 13, wherein the fingerprint sensing circuit 12 includes sensing electrodes and driving electrodes insulated from each other, wherein the sensing electrodes include a plurality of sensing sub-electrodes 1211 , and the driving electrodes include a plurality of driving sub-electrodes 1221 .

Preferably, the sensing electrodes and the driving electrodes are respectively located on two sides of the FPC; or, the sensing electrodes and the driving electrodes are located on the same side of the FPC. Arranging the sensing electrodes and the driving electrodes on the FPC is beneficial to improving the integration of the fingerprint identification module and reducing the production cost.

Preferably, when the sensing electrode and the driving electrode are located on the same side of the FPC, the module further includes an insulating layer between the sensing electrode and the driving electrode, for connecting the sensing electrode and the driving electrode Insulation is performed to prevent signal crosstalk between the sensing electrodes and the driving electrodes.

Preferably, the driving electrodes include a plurality of mutually insulated driving sub-electrodes, and the driving sub-electrodes are strip-shaped and distributed in parallel along the first direction; by setting the driving electrodes as a plurality of mutually insulated driving sub-electrodes The electrodes are beneficial to improve the recognition accuracy of the fingerprint recognition module.

Preferably, the sensing electrodes include a plurality of mutually insulated sensing sub-electrodes, and the sensing sub-electrodes are strip-shaped and distributed in parallel along the second direction; by setting the sensing electrodes as a plurality of mutually insulated sensing sub-electrodes The electrodes are beneficial to improve the recognition accuracy of the fingerprint recognition module.

Preferably, the driving sub-electrodes and the sensing sub-electrodes are intersected; by intersecting the driving sub-electrodes and the sensing sub-electrodes, the number of capacitors in the fingerprint identification module can be increased, which is beneficial to improve fingerprint identification. Module recognition accuracy. Meanwhile, the driving sub-electrodes and the sensing sub-electrodes may also be arranged in parallel.

Preferably, it also includes a fingerprint identification chip, the fingerprint identification chip is located on one side of the FPC, electrically connected to the driving electrodes and the sensing electrodes, and is used to detect changes in the capacitance formed by the driving electrodes and the sensing electrodes , and send the detection result to the external circuit through the FPC.

Preferably, the module further includes a protective layer, the protective layer covers the sensing electrodes and the driving electrodes, so as to prevent the internal structure of the fingerprint recognition module from being damaged.

specific:

Referring to FIG. 2, the sensing electrodes 121 are located above the flexible circuit board 11, and the driving electrodes 122 are located below the flexible circuit board 11; the driving electrodes 122 extend along a first direction, and the sensing electrodes 121 extend along a second direction. extend.

Referring to FIG. 3 , the sensing electrodes 121 and the driving electrodes 122 may also be located on the same side of the flexible circuit board 11 , when the sensing electrodes 121 and the driving electrodes 122 are located on the same side of the flexible circuit board 11 In this case, an insulating layer 30 is also included between the sensing electrodes 121 and the driving electrodes 122 to insulate the sensing electrodes 121 and the driving electrodes 122 to prevent signal generation between the sensing electrodes 121 and the driving electrodes 122. crosstalk.

Further, referring to FIG. 4 , the sensing electrode 121 includes a plurality of sensing sub-electrodes 1211 insulated from each other, and the sensing sub-electrodes 1211 are strip-shaped and distributed in parallel along the second direction; the width of the sensing sub-electrodes 1211 is 30um-50um, and the distance between every two adjacent sensing sub-electrodes 1211 is 50um-100um. Since the volume of the fingerprint identification module is very small, in order to improve the accuracy of the fingerprint identification module, in the first embodiment of the present invention, the width of the sensing sub-electrode 1211 is 30um-50um. At the same time, the sensing sub-electrode 1211 may also be wavy, zigzag or other irregular shapes.

The driving electrode 122 includes a plurality of driving sub-electrodes 1221 insulated from each other. The driving sub-electrodes 1221 are strip-shaped and distributed in parallel along the first direction; the width of the driving sub-electrodes 1221 is 300um-500um, and every two The distance between two adjacent induction sub-electrodes is 30-50um. Since the volume of the fingerprint identification module is very small, in order to increase the accuracy of the fingerprint identification module, in Embodiment 1 of the present invention, the width of the driving sub-electrode 1221 is 300-500um. At the same time, the driving sub-electrode 1221 may also be in a wave shape, a zigzag shape or other irregular shapes.

The specific embodiment of the present invention does not specify the width of the driving sub-electrode 1221 and the width of the sensing sub-electrode 1211, the distance between every two adjacent sensing sub-electrodes and the distance between every two adjacent driving sub-electrodes. The spacing is specifically limited.

The fingerprint identification chip 13 is located on one side of the flexible circuit board 11, and is electrically connected to the driving electrodes 122 and the sensing electrodes 121, and is used to detect changes in the capacitance formed by the driving electrodes 122 and the sensing electrodes 121, that is, The changes of the electrical signals on the driving electrodes 122 and the sensing electrodes 121 are respectively detected, and the detection results are sent to an external circuit through the FPC.

Figure 5 is a partially enlarged view of the fingerprint sensing circuit 12; in Figure 5, 50 represents the position touched by the finger, the first direction is horizontal, the second direction is vertical, each horizontal line represents a horizontal array, each vertical Lines represent a vertical array, 1221 _i-1 , 1221 _i and 1221 _i+1 represent three adjacent horizontal arrays, that is, the driving electrodes of the fingerprint recognition module, wherein, i=1, 2, 3, 4.. ....; 1211 _j-1 , 1211 _j and 1211 _j+1 represent three adjacent longitudinal arrays, that is, the sensing electrodes of the fingerprint recognition module; wherein, j=1, 2, 3, 4... … Each of the horizontal arrays and each of the longitudinal arrays respectively intersect each other to form a plurality of intersection points. For example, the intersection point where the horizontal array 1221 _i intersects the vertical array 1211 _j is point B( _xi , y _j ).

After the fingerprint recognition chip scans and detects the horizontal array 1221i _-1 , then scans _1221i , detects the actual voltage value output from the horizontal array _1221i in turn, and compares it with the reference voltage value in the fingerprint recognition chip. If the detected actual voltage value is the same as the reference voltage value, it means that there is no touched point on the horizontal array 1221 _i ; if the detected actual voltage value is different from the reference voltage value _, it means that there is The touched point, at this time, the vertical coordinate y of the touched point can be determined.

At this time, the fingerprint recognition chip scans each vertical array step by step. After scanning and detecting the vertical array 1211 _j-1 , the detection unit then scans the vertical array 1211 _j and detects the output of each point in the vertical array 1211 _j If the detected actual voltage value is the same as the reference voltage value, it means that there is no touched point on the vertical array; if the detected actual voltage value is different from the reference voltage value, it means that the vertical array 1211 There is a touched point on _j , and the abscissa x of the touched point can be determined; comprehensively considering the horizontal array and the vertical array, if there is a touched point on the horizontal array 1221 _i , there is also a touched point on the vertical array 1211 _j , then according to the corresponding vertical coordinate y of the horizontal array 1221 _i and the corresponding horizontal coordinate x of the vertical array 1211 _j , the coordinates of the touched point B can be obtained as (x, y).

Then, referring to Figure 6, during the sliding process of the finger, the protrusions of the fingerprint lines will pass through multiple electrodes and their intervals in the X direction, and then in different series of fingerprint image fragments, the capacitance changes caused by the protrusions of the lines, It will be reflected in the capacitance change of the adjacent X-direction electrodes. Analyze this series of pictures with software, and you can get images higher than the resolution of the physical electrodes in the Y direction. Therefore, output the coordinates of each contact point detected to form a frame of fingerprint images; when the finger slides along the Y direction in the fingerprint identification module, multiple frames of fingerprint images 61 are obtained, and finally the multiple frames obtained The fingerprint images are synthesized into a complete fingerprint image 62, that is, the finally detected fingerprint image, and it is further judged whether the fingerprint image matches the preset fingerprint image.

Further, the fingerprint identification module 10 also includes a protective layer covering the sensing electrodes 121 and the driving electrodes 122 .

An embodiment of the present invention also provides a display device, the display device includes a display panel, an FPC of the display panel for providing electrical signals to the display panel, and the display device further includes the above-mentioned fingerprint recognition module.

Preferably, the FPC in the fingerprint recognition module is the FPC of the display panel in the display device, and the PFC can be formed through one process, which can reduce process steps and reduce production costs.

Preferably, the display device further includes a touch module, and the touch module is connected to an external circuit through the FPC; through the touch module, the touch function of the display device can be realized.

Preferably, the fingerprint identification chip is electrically connected to the fingerprint sensing circuit. The fingerprint recognition chip can be used to detect the change of the capacitance formed by the driving electrode and the sensing electrode in the fingerprint driving circuit, and send the detection result to an external circuit through the FPC.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention also intends to include these modifications and variations.

Claims (11)

1. A fingerprint recognition module, characterized in that, comprising: Flexible circuit board FPC; The fingerprint sensing circuit arranged on the flexible circuit board includes driving electrodes and sensing electrodes insulated from each other, wherein the driving electrodes extend along a first direction, and the sensing electrodes extend along a second direction, and the driving electrodes include A plurality of mutually insulated driving sub-electrodes, the width of the driving sub-electrodes is 300um-500um, and the sensing electrode includes a plurality of mutually insulated sensing sub-electrodes, the width of the sensing sub-electrodes is 30um-50um; A fingerprint identification chip, the fingerprint identification chip is located on one side of the FPC, is electrically connected to the driving electrodes and the sensing electrodes, and is used to detect changes in the capacitance formed by the driving electrodes and the sensing electrodes, and pass the detection results through The FPC is sent to the external circuit; wherein, when the finger slides, multiple frames of fingerprint images are obtained, and the multiple frames of fingerprint images are synthesized into a complete fingerprint image to obtain the final detected image and match it with the preset fingerprint image. 2. The module according to claim 1, wherein the sensing electrodes and the driving electrodes are respectively located on both sides of the FPC; or The sensing electrodes and driving electrodes are located on the same side of the FPC. 3. The module according to claim 2, wherein when the sensing electrodes and the driving electrodes are located on the same side of the FPC, the module further comprises an insulating layer between the sensing electrodes and the driving electrodes . 4 . The module according to claim 2 , wherein the driving sub-electrodes are strip-shaped and distributed in parallel along the first direction. 5 . The module according to claim 2 , wherein the induction sub-electrodes are strip-shaped and distributed in parallel along the second direction. 6 . The module according to claim 1 , wherein the driving sub-electrodes and the sensing sub-electrodes are intersected. 7. The module according to any one of claims 1-6, characterized in that the module further comprises a protective layer, and the protective layer covers the sensing electrodes and the driving electrodes. 8. A display device, the display device comprising a display panel, an FPC of the display panel for providing electrical signals to the display panel, characterized in that the device further comprises the The fingerprint identification module described above. 9. The device according to claim 8, wherein the FPC in the fingerprint identification module is an FPC of a display panel in a display device. 10. The device according to claim 9, wherein the display device further comprises a touch module, and the touch module is connected to an external circuit through the FPC. 11. The device according to claim 8, wherein the fingerprint identification chip is electrically connected to the fingerprint sensing circuit.