WO2018169301A1

WO2018169301A1 - Ultrasonic fingerprint sensor and method for manufacturing same

Info

Publication number: WO2018169301A1
Application number: PCT/KR2018/002973
Authority: WO
Inventors: 박상영; 박영태
Original assignee: 주식회사 베프스
Priority date: 2017-03-16
Filing date: 2018-03-14
Publication date: 2018-09-20

Abstract

Provided are an ultrasonic fingerprint sensor and a method for manufacturing same. The method for manufacturing the ultrasonic fingerprint sensor may comprise the steps of: (a) manufacturing a first piezoelectric layer formed of piezoelectric rods arranged in the form of an m x n sensor array; and (b) attaching, to the lower portion of the first piezoelectric layer, a second piezoelectric layer in the form of a single piezoelectric sheet.

Description

Ultrasonic Fingerprint Sensor and Manufacturing Method Thereof

The present invention relates to an ultrasonic fingerprint sensor and a method of manufacturing the same.

Biometrics is a technology that provides a high level of security, and fingerprint technology is one of the important biometric technologies.

In general, fingerprint recognition extracts a specific pattern or feature point (for example, a branching point at which the ridge of the fingerprint branches, a disadvantage of ending the ridge) from a fingerprint image formed by receiving a fingerprint from the user, and a pattern of a pre-stored fingerprint image or It is performed to contrast with the feature point.

The fingerprint sensor for recognizing a user's fingerprint may be manufactured in the form of a module including a peripheral component or a structure, for example, and may be implemented integrally with a physical function key. have.

1 schematically illustrates the configuration of an ultrasonic fingerprint sensor according to the prior art.

Referring to FIG. 1, the ultrasonic fingerprint sensor may be configured to be electrically connected to a plurality of piezoelectric rods 100 and upper ends of the plurality of piezoelectric rods 100 arranged to form an array of mxn-type sensors. The plurality of first electrode bars 106 arranged in one direction and the plurality of second electrode bars 108 arranged in a second direction perpendicular to the first direction to be electrically connected to lower ends of the plurality of piezoelectric rods 100. ).

The depicted reference numeral 102 denotes a shielding layer, which is a protective coating formed on top of the first electrode bar 106 so that the finger is placed in proximity to the sensor array, and reference numeral 104 denotes a sensor array opposite the shielding layer 102. The support is attached to the end of the support for supporting the plurality of piezoelectric rods 100 from the bottom.

Here, the piezoelectric rod 100 is formed of a material having piezo characteristics, for example, PZT (lead zirconate titanate), PST, Quartz, (Pb, Sm) TiO3, PMN (Pb (MgNb) O3 The material may include at least one of) -PT (PbTiO3), PVDF, or PVDF-TrFe.

A voltage having a resonant frequency of an ultrasonic band is applied to the first electrode bar 106 connected to the upper end of the piezoelectric rod 100 and the second electrode bar 108 connected to the lower end of the piezoelectric rod 100 to thereby move the piezoelectric rod 100 up and down. When vibrating, the ultrasonic signal having a predetermined frequency is generated and emitted as illustrated in FIG.

In the state where the finger is not in contact with the shielding layer 102, the ultrasonic signal emitted from the piezoelectric rod 100 does not pass through the interface between the piezoelectric rod 100 and the air and returns to the inside of the piezoelectric rod 100.

However, in the state where the finger is in contact, a part of the emitted ultrasonic signal penetrates the interface between the skin of the finger and the piezoelectric rod 100 and proceeds to the inside of the finger. The pattern can be detected.

In the above-described ultrasonic fingerprint sensor, each of the piezoelectric rods 100 operates as a transmitting end Tx and a receiving end Rx of the ultrasonic signal. In this case, even when transmitting an ultrasonic signal, it is inconvenient to perform individual control according to the m x n array.

In this regard, Korean Laid-Open Patent Publication No. 10-2011-0138257 discloses an improved piezoelectric identification device and its application.

According to the present invention, the transmitter Tx and the receiver Rx are manufactured in different processes (different thickness / material / sintering temperature, etc.) in consideration of their operating characteristics, and then combined into one module to transmit and receive ultrasonic signals. It is an object of the present invention to provide an ultrasonic fingerprint sensor and a method of manufacturing the same.

The present invention is to provide an ultrasonic fingerprint sensor and a method of manufacturing the same having a smaller number of transmitters (Tx) than the receiver (Rx) to improve the control convenience in the ultrasonic signal transmission process.

An object of the present invention is to provide an ultrasonic fingerprint sensor and a method of manufacturing the same, which can shorten a fingerprint recognition time by subdividing an ultrasonic signal transmission time point for a plurality of transmitters Tx.

Other objects of the present invention will be readily understood through the following description.

According to an aspect of the present invention, a method of manufacturing an ultrasonic fingerprint sensor, comprising: (a) manufacturing a first piezoelectric layer having a piezoelectric rod in the form of an m x n sensor array; (b) attaching a second piezoelectric layer in the form of a piezoelectric sheet to a lower portion of the first piezoelectric layer, a method of manufacturing an ultrasonic fingerprint sensor is provided.

According to another aspect of the present invention, a method of manufacturing an ultrasonic fingerprint sensor, the method comprising the steps of: (a) manufacturing a first piezoelectric layer formed with a piezoelectric rod in the form of an m x n sensor array; (b) attaching a base substrate to the lower portion of the first piezoelectric layer: (c) attaching a second piezoelectric layer in the form of one piezoelectric sheet to side surfaces of the first piezoelectric layer and the base substrate. A method of manufacturing an ultrasonic fingerprint sensor is provided.

The first piezoelectric layer may function as a receiver of an ultrasonic fingerprint sensor, and the second piezoelectric layer may function as a transmitter of an ultrasonic fingerprint sensor.

Said step (a) comprises the steps of: (a1) providing a first piezoelectric sheet; (a2) cutting in parallel in a first direction at predetermined intervals to a depth at which a remaining region remains on the second surface side at the first surface of the first piezoelectric sheet, and at the second surface of the ceramic sintered body Forming a ceramic workpiece by cutting in parallel in a second direction perpendicular to the first direction at predetermined intervals at a depth at which the remaining region remains on the first surface side; (a3) filling an insulating material into a groove formed in the ceramic workpiece by the cutting in the step (a2); (a4) removing the remaining regions respectively present on the first surface side and the second surface side such that the piezoelectric rods are arranged and exposed in an array form on the first surface and the second surface, respectively.

Alternatively, step (a) may include: (a1) providing a first piezoelectric sheet having a first metal layer formed on the first surface and having a second metal layer formed on a second surface not in contact with the first surface; (a2) cutting the first metal layer and the piezoelectric sheet at predetermined intervals in parallel in a first direction; (a3) filling the gap formed in the first piezoelectric sheet by the step (a2) with a predetermined insulating material; (a4) cutting the first piezoelectric sheet and the second metal layer at predetermined intervals in parallel in a second direction orthogonal to a first direction; And (a5) filling the gap formed in the first piezoelectric sheet by the step (a4) with a predetermined insulating material.

Also provided is an ultrasonic fingerprint sensor manufactured by the above-described method for manufacturing an ultrasonic fingerprint sensor.

On the other hand, according to another aspect of the present invention, a receiver including a first piezoelectric layer formed with a piezoelectric rod in the form of m x n sensor array; An ultrasonic fingerprint sensor is provided, including a transmitter including a second piezoelectric layer in the form of one piezoelectric sheet, wherein the transmitter is attached to a lower portion of the receiver.

Alternatively, according to another aspect of the invention, the receiving unit including a first piezoelectric layer formed with a piezoelectric rod in the form of m x n sensor array and a base substrate attached to the lower portion of the first piezoelectric layer; An ultrasonic fingerprint sensor is provided, including one or more transmitters including a second piezoelectric layer in the form of one piezoelectric sheet, wherein the transmitter is attached to a side of the receiver.

The first piezoelectric layer may be formed using a ceramic sintered body or a composite piezoelectric material produced by an incomplete sintering condition.

The second piezoelectric layer may be a second piezoelectric sheet made of a completely sintered body.

When there are K transmitters, the ultrasonic signals may be divided in T / K intervals within a period T corresponding to a resonance frequency and sequentially generated in K transmitters.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the invention.

According to an embodiment of the present invention, the transmitter Tx and the receiver Rx are manufactured in different processes (different thickness / material / sintering temperature, etc.) in consideration of their operating characteristics, and are then combined into one module to make an ultrasonic signal. There is an effect that shows excellent characteristics in the transmission and reception of a.

In addition, there is an effect that can improve the control convenience in the ultrasonic signal transmission process by providing a smaller number of transmitters (Tx) than the receiver (Rx).

In addition, there is an effect that the fingerprint recognition time can be shortened by subdividing the ultrasonic signal transmission time points for the plurality of transmitters Tx.

1 is a view schematically showing the configuration of an ultrasonic fingerprint sensor according to the prior art.

2 is a view for explaining the shape and operation of the piezoelectric rod according to the prior art.

Figure 3 illustrates the shape of the ultrasonic fingerprint sensor according to an embodiment of the present invention.

4 and 5 illustrate a manufacturing process of an ultrasonic fingerprint sensor according to an embodiment of the present invention.

6 is a view illustrating a shape of a receiver Rx 'included in an ultrasonic fingerprint sensor according to another exemplary embodiment of the present invention.

7 is a view for explaining a manufacturing process of the receiving unit (Rx ') of the ultrasonic fingerprint sensor according to another embodiment of the present invention.

8 is a plan view and a cross-sectional view of the ultrasonic fingerprint sensor according to another embodiment of the present invention.

9 is a view for explaining a manufacturing process of the ultrasonic fingerprint sensor according to another embodiment of the present invention.

10 is a time graph of ultrasonic signal generation for fingerprint recognition in an ultrasonic fingerprint sensor according to another embodiment of the present invention.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

If an element such as a layer, region or substrate is described as being on or "onto" another element, the element may be directly above or directly above another element and There may be intermediate or intervening elements. On the other hand, if one element is mentioned as being "directly on" or extending "directly onto" another element, no other intermediate elements are present. In addition, when one element is described as being "connected" or "coupled" to another element, the element may be directly connected to or directly coupled to another element, or an intermediate intervening element may be present. have. On the other hand, when one element is described as being "directly connected" or "directly coupled" to another element, no other intermediate element exists.

"Below" or "above" or "upper" or "lower" or "horizontal" or "lateral" or "vertical" Relative terms such as "vertical" and the like may be used herein to describe a relationship of one element, layer or region to another element, layer or region, as shown in the figures. It is to be understood that these terms are intended to encompass other directions of the device in addition to the orientation depicted in the figures.

In addition, in the description with reference to the accompanying drawings, the same components regardless of reference numerals will be given the same or related reference numerals and redundant description thereof will be omitted. In the following description of the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

3 is a diagram illustrating a shape of an ultrasonic fingerprint sensor according to an embodiment of the present invention, and FIGS. 4 and 5 are views illustrating a manufacturing process of an ultrasonic fingerprint sensor according to an embodiment of the present invention.

The ultrasonic fingerprint sensor 300A according to the exemplary embodiment of the present invention is characterized in that the transmitter Tx and the receiver Rx are separated from each other in the vertical direction.

Referring to FIG. 3, the ultrasonic fingerprint sensor 300A according to the present exemplary embodiment includes a receiver Rx including a first piezoelectric layer 310 in which a plurality of piezoelectric rods 311 are arranged in an mxn-type sensor array; The transmission unit Tx including the second piezoelectric layer 320 formed in the shape of one piezoelectric sheet may be included.

The first piezoelectric layer 310 has a plurality of first electrode bars 313 arranged on a first surface in a predetermined direction, and a first electrode bar 313 is arranged on a second surface which is not in contact with the first surface. It may further include a plurality of second electrode bars 314 arranged in the direction orthogonal to each other.

Each piezoelectric rod 311 may be formed in the shape of a bar or rod having a first length R1.

Each piezoelectric rod 311 has a piezo characteristic, for example, PZT (lead zirconate titanate), PST, Quartz, (Pb, Sm) TiO3, PMN (Pb (MgNb) O3) -PT ( PbTiO 3), PVDF or PVDF-TrFe may be formed using a piezoelectric material containing at least one material.

The first piezoelectric layer 310 may be manufactured using a ceramic sintered body sintered by an incomplete sintering condition instead of a complete sintered body. Alternatively, the first piezoelectric layer 310 may be manufactured using a composite piezoelectric material.

In addition, the space between the respective piezoelectric rods 311 constituting the sensor array may be filled with the insulating material 312. The insulating material 312 may be determined as a material having a property of electrically separating the respective piezoelectric rods 311 to suppress mutual interference with respect to the reflected ultrasonic signals from the finger received from the neighboring piezoelectric rods.

For example, PZT (lead zirconate titanate), PST, Quartz, (Pb, Sm) TiO3, PMN (Pb (MgNb), and the like may also have piezoelectric characteristics. O 3) -PT (PbTiO 3), PVDF or PVDF-TrFe may be formed using a piezoelectric material including at least one material.

In particular, the second piezoelectric layer 320 may be made of a fully sintered body capable of bringing the output of the resonance frequency high so that the generated ultrasonic waves can reach a sufficient position for fingerprint recognition.

The second piezoelectric layer 320 may have a thickness greater than or equal to the second length R2 for high output. Here, the second length R2 may be larger than the first length R1 (R2> R1). This is because the transmitter Tx, which should generate a high output ultrasonic signal, should have a sufficient thickness, while the second piezoelectric layer 320 corresponding to the receiver Rx has a relatively thin thickness but is reflected by the finger. Because it is enough to receive it.

In addition, the second piezoelectric layer 320 may have an area corresponding to the first piezoelectric layer 310 forming the m x n sensor array of the receiver Rx. This is to allow the ultrasonic signal generated in the second piezoelectric layer 320 to affect the entire first piezoelectric layer 310.

In this embodiment, the second piezoelectric layer 320 may also be provided with an electrode for applying a voltage to generate an ultrasonic signal. Here, the electrode of the second piezoelectric layer 320 has a structure such that an electrical connection is not established with an electrode (particularly, the second electrode bar 314) of the first piezoelectric layer 310 or an insulating material therebetween. It may be intervened.

When a voltage is applied through the electrode of the second piezoelectric layer 320, the second piezoelectric layer 320 generates and emits an ultrasonic signal. In the state where the finger is in contact, a part of the emitted ultrasonic signal is returned by colliding with the melting or valley of the fingerprint, and the fingerprint pattern may be detected by receiving the signal from the first piezoelectric layer 310 and converting the signal into an electrical signal. .

Hereinafter, a method of manufacturing the ultrasonic fingerprint sensor according to the present embodiment will be described with reference to FIGS. 4 and 5.

4 and 5, in step (a), a first piezoelectric sheet 301 is provided. As described later, the first piezoelectric sheet 301 has a sensor array formed to function as the first piezoelectric layer described above.

The piezoelectric sheet is, for example, a piezoelectric ceramic powder such as PZT, which has been heat-treated into a thin sheet, and may be referred to as a sheet or a film depending on its thickness, but will be referred to herein as a sheet.

As described above, the first piezoelectric sheet 301 provided in step (a) may be a ceramic sintered body produced by sintering under incomplete sintering conditions.

Ceramic sinters, including piezoelectric sheet forms, are generally formed by full sintering conditions for piezoelectric materials such as PZT and the like. The temperature conditions and time conditions specified as complete sintering conditions may vary, for example, such that the ceramic sinter formed has a density of about 97-99% of the theoretical density.

However, the ceramic sintered body produced by the complete sintering condition is excellent in piezoelectric ceramic characteristics, but has a disadvantage in that the machinability is relatively poor, such that the cutting speed is limited to a speed of about 1-3 mm per second.

In contrast, the first piezoelectric sheet 301 provided in step (a) may be a ceramic sintered body produced by an incomplete sintering condition.

Here, the incomplete sintering conditions are relatively poorly specified one or more of the heating temperature, heating time, etc. compared to the above-mentioned complete sintering conditions, so that the resulting ceramic sintered body has a relatively low density (e.g., For example, about 80-90% of the theoretical density).

The ceramic sintered body produced by the incomplete sintering conditions has a relatively low sintering level compared to the ceramic sintered body produced by the complete sintering conditions, and thus the properties as piezoelectric ceramics are relatively insufficient, but the mechanical workability is relatively excellent.

Alternatively, the first piezoelectric sheet 301 provided in step (a) may be generated by using a composite piezoelectric material. Composite piezoelectric materials include other complex materials in addition to pure piezoelectric materials such as PZT, which are relatively poor as piezoelectric ceramics, but have excellent mechanical processability, and are used for mass production. .

In step (b), at the first surface (for example, the upper surface) of the first piezoelectric sheet 301, cutting is performed at predetermined intervals (L2 shown) in parallel in the first direction to form grooves. The ceramic workpiece 302 is formed. Here, the cutting depth is limited to a depth having a length relatively smaller than the thickness of the first piezoelectric sheet 301 so that the remaining region remains on the second surface side.

Subsequently, in step (c), the ceramic workpiece 302 having grooves parallel to the first direction is formed to be orthogonal to the first direction with respect to the second surface (for example, the lower surface) that is not in contact with the first surface. Dicing at predetermined intervals in parallel in two directions. Even in this case, the cutting depth is limited to a depth having a relatively small grinding compared to the thickness of the first piezoelectric sheet 301 so that the remaining region remains on the first surface side. The groove formation in step (c) may be carried out in a state of inverting the vertical direction of the ceramic workpiece 302 for convenience of work.

Subsequently, in step (d), the ceramic workpiece 302 in which the groove is formed in the first direction on the first surface and the groove in the second direction on the second surface may be sintered according to the complete sintering conditions.

In the process of sintering the incompletely sintered ceramic workpiece 302 according to the complete sintering conditions, shrinkage of the ceramic workpiece 302 occurs, so that the length of the ceramic workpiece 302 and the width of the grooves are respectively reduced ( That is, L1> L3, L2> L4).

As a result, the spacing of the piezoelectric rods 311 to be described later becomes more compact, so that an ultrasonic fingerprint sensor having a higher resolution can be manufactured. In the present embodiment, step (d) may be omitted as necessary.

Subsequently, in step (e), the grooves respectively cut in the first direction and the second direction and formed in the ceramic workpiece 302 are filled with the insulating material 312.

Subsequently, in step (f), the first surface of the ceramic workpiece 302 in which each groove is filled with the insulating material 312 is polished (CMP) to remove the remaining region held on the first surface side.

The polishing process of step (f) exposes the piezoelectric rods 311 arranged in the form of an mxn array on the first surface side, and in step (g) any one of the third direction (that is, the first direction and the second direction). A plurality of first electrode bars 313 are arranged in each of the plurality of piezoelectric rods 311 and electrically connected to upper ends of the plurality of piezoelectric rods 311.

Subsequently, in step (h), the second surface of the ceramic workpiece 302 in which each groove is filled with the insulating material 312 is polished (CMP) to remove the remaining region held on the second surface side.

The polishing process of step (h) exposes the piezoelectric rods 311 arranged in the form of an mxn array on the second surface side, and in step (i) the other one of the fourth direction (ie, the first direction and the second direction). A plurality of second electrode bars 314 are arranged, respectively, and electrically connected to upper ends of the plurality of piezoelectric rods 311. Steps (h) and (i) described above may be performed in an upside down direction of the ceramic workpiece 302 for convenience of operation.

Manufacturing of the receiver Rx is completed through the above steps (a) to (i).

Subsequently, in step (j), a second piezoelectric sheet made of a completely sintered body may be prepared and attached to the bottom of the receiver Rx. The second piezoelectric sheet functions as a second piezoelectric layer 320 that generates and emits an ultrasonic signal by applying a voltage, and corresponds to the transmitter Tx.

The second piezoelectric layer 320 may be attached to the bottom surface of the receiver Rx by using an adhesive, or may be attached by pressing and bonding a metal and a ceramic at high temperature and pressure.

The second piezoelectric layer 320 may have a thickness R2 sufficient to generate an ultrasonic signal and may have an area corresponding to the receiver Rx.

As described above, in the manufacturing method of the ultrasonic fingerprint sensor according to the present embodiment, grooves are performed on the first piezoelectric sheet 301 formed according to incomplete sintering conditions or made of a composite piezoelectric material during manufacturing of the receiver Rx. There is an advantage that the ease of processing and the acceleration of the process speed can be achieved.

In addition, since the transmitter Tx is formed of a second piezoelectric layer 320 in the form of a sheet having a sufficient area, an ultrasonic signal can be generated corresponding to the entire area of the receiver Rx, so that individual control according to the sensor array is possible. There is an advantage that is not required.

6 is a view illustrating a shape of a receiver Rx 'included in an ultrasonic fingerprint sensor according to another embodiment of the present invention, and FIG. 7 is a view of the receiver Rx' of the ultrasonic fingerprint sensor according to another embodiment of the present invention. It is a figure for demonstrating a manufacturing process.

Referring to FIG. 6, the receiver Rx ′ of the ultrasonic fingerprint sensor includes a piezoelectric layer (signal receiving layer) in which a plurality of piezoelectric rods 100a are arranged in an mxn-type sensor array, and a first direction on a first surface of the piezoelectric layer. A plurality of first electrode bars 325a arranged in a second direction, and a plurality of second electrode bars 335a arranged in a second direction, which is a direction orthogonal to the first direction, on a second surface not in contact with the first surface of the piezoelectric layer. It may include.

Each piezoelectric rod 100a formed in the shape of a bar or a rod having a predetermined length has a piezo characteristic as described above, for example, PZT (lead zirconate titanate), PST, and the like. , Quartz, (Pb, Sm) TiO 3, PMN (Pb (MgNb) O 3) -PT (PbTiO 3), PVDF or PVDF-TrFe, and may be formed using a piezoelectric material including at least one material.

The space between the piezoelectric rods 100a constituting the sensor array may be filled with the insulating material 340a. The insulating material 340a may be determined as a material having a characteristic of not suppressing vertical vibration of the piezoelectric rod 100a to which voltage is applied using the first and

second electrode bars

325a and 335a.

Hereinafter, a method of manufacturing the ultrasonic fingerprint sensor according to the present invention will be described with reference to FIG. 7.

Referring to FIG. 7, in step (a), a sensor array is formed to prepare a first piezoelectric sheet 310a to function as the aforementioned piezoelectric layer (signal receiving layer).

The first piezoelectric sheet 310a provided in step (a) may be generated by incomplete sintering conditions. Alternatively, the first piezoelectric sheet 310a provided in step (a) may be generated by using a composite piezoelectric material.

In step (b), each of the first surface (eg, upper surface shown) of the first piezoelectric sheet 310a and the second surface (eg, lower surface shown) not in contact with the first surface First and

second metal layers

320a and 330a having a predetermined thickness are formed, respectively.

Each of the first and

second metal layers

320a and 330a may be attached to each surface of the first piezoelectric sheet 310a using a conductive paste, or may be attached by pressing metal and ceramic at high temperature and pressure. It may be attached to the piezoelectric sheet 310a in a way.

In step (c), the first piezoelectric sheet 310a to which the first and

second metal layers

320a and 330a are attached is cut at predetermined intervals in parallel in the first direction, respectively, in the first direction. A plurality of first electrode bars 325a arranged are formed.

The cutting depth is performed at a depth at which the thicknesses corresponding to the first metal layer 320a and the first piezoelectric sheet 310a are completely cut. In this case, only the lower end of the first piezoelectric sheet 310a may be processed to be cut. However, even if the second metal layer 330a is cut to some depth, if the second metal layer 330a is not completely cut, the conductivity of the second metal layer 330a may be maintained. There is a number.

Immediately before or after the cutting process described above, a plating process may be performed to form terminals required for future module fabrication. If the plating for forming the terminal is performed immediately before the cutting process, the terminals corresponding to each of the plurality of first electrode bars 325a are formed together with only the above cutting process, thereby simplifying the manufacturing process.

In step (d), the gap formed in the first piezoelectric sheet 310a by cutting to form the first electrode bar 325a is transferred to the insulating material 340a.

In step (e), the first piezoelectric sheet 310a to which the first and

second metal layers

320a and 330a are attached is diced at predetermined intervals in parallel in a second direction perpendicular to the first direction. , A plurality of second electrode bars 335a arranged in the second direction, respectively.

As described above in step (c), the cutting depth is performed at a depth at which the thicknesses corresponding to the second metal layer 320a and the first piezoelectric sheet 310a are completely cut, and fabrication of the module immediately before or after the cutting process is performed. A plating process may be performed to form terminals required for the test.

The first piezoelectric sheet 310a is etched in a direction orthogonal to form the first electrode bar 325a and the second electrode bar 335a to form a plurality of piezoelectric rods 100a forming an mxn-type sensor array. Done.

In step (f), the gap formed in the first piezoelectric sheet 310a by cutting to form the second electrode bar 335a is transferred to the insulating material 340a.

Steps (e) and (f) described above may be operated while being turned upside down and rotated 90 degrees in the horizontal direction for the convenience of manufacturing the ultrasonic fingerprint sensor.

The first electrode bar for applying a voltage to each of the plurality of piezoelectric rods 100a and the plurality of piezoelectric rods 100a, which form an mxn-type sensor array and is surrounded by the insulating material 340a, by the simple process described above. An ultrasonic fingerprint sensor including a 325a and a second electrode bar 335a may be manufactured.

In addition, since terminals for electrical connection are formed at the external terminals on the first electrode bar 325a and the second electrode bar 335a, the receiving unit Rx 'module can be manufactured by itself.

The receiver Rx 'manufactured as described above may have a second piezoelectric sheet made of a fully sintered body as shown in FIG. 5 (j), and may be attached to a lower portion thereof to manufacture an ultrasonic fingerprint sensor. Here, the second piezoelectric sheet functions as a second piezoelectric layer that generates and emits an ultrasonic signal by applying a voltage, and corresponds to the transmitter Tx.

8 is a plan view and a cross-sectional view taken along line AA of the ultrasonic fingerprint sensor according to another embodiment of the present invention, Figure 9 is a view for explaining a manufacturing process of the ultrasonic fingerprint sensor according to another embodiment of the present invention, 10 is a time graph of ultrasonic signal generation for fingerprint recognition in an ultrasonic fingerprint sensor according to another embodiment of the present invention.

Ultrasonic fingerprint sensor 300B according to another embodiment of the present invention is characterized in that the transmitting unit (Tx) and the receiving unit (Rx) is arranged separated in the horizontal direction. In particular, the transmitter Tx may be disposed outside (ie, side) of the receiver Rx.

In the drawing, although the receiver Rx has a shape with the first embodiment as shown in FIG. 3 and is manufactured by the manufacturing process of FIGS. 4 and 5, this is only one embodiment, and FIG. 6. Of course, it may also be Rx 'manufactured by the manufacturing process of FIG. 7 while having the same shape as that of the second embodiment as shown in FIG. Hereinafter, for convenience of understanding and explanation of the invention, it will be described on the assumption that the receiver has a shape as shown in FIG. 3 (Rx).

Referring to FIG. 8, the ultrasonic fingerprint sensor 300B according to the present exemplary embodiment includes a receiver Rx including a first piezoelectric layer 310 in which a plurality of piezoelectric rods 311 are arranged in an mxn-type sensor array. One or more transmitters Tx1 to Tx4 may be formed in the shape of one piezoelectric sheet and include second piezoelectric layers 360a to 360d disposed outside the receiver Rx. In the figure, a case in which the transmitter is arranged in all four directions of the receiver Rx is illustrated, but this is only an example and may be arranged in only one to three directions.

In the receiver Rx, a base substrate 350 for supporting the first piezoelectric layer 310 may be provided below. The base substrate 350 has a rigid characteristic and may be formed of glass, for example.

The total thicknesses of the first piezoelectric layer 310 and the base substrate 350 correspond to the thicknesses of the second piezoelectric layers 360a to 360d, so that the ultrasonic fingerprint sensor 300B may be entirely horizontal.

Referring to FIG. 9, the processes from steps (a) to (i) of manufacturing the first piezoelectric layer 310 are the same as those described above with reference to FIGS. 4 and 5.

Subsequently, in step (k), the base substrate 350 may be attached to the lower portion of the first piezoelectric layer 310. The base substrate 350 serves as a support for supporting the first piezoelectric layer 310 to maintain horizontality, and the base substrate 350 may have a thickness corresponding to the transmission parts Tx1 to Tx4 to be attached to the outside. To this end, the thickness of the base substrate 350 may correspond to the difference between the thickness R2 of the second piezoelectric layers 360a to 360d and the thickness R1 of the first piezoelectric layer 310.

Subsequently, in step (1), a second piezoelectric sheet made of a full sintered body may be prepared and attached to the outside of the receiver Rx to which the base substrate 350 is attached. The second piezoelectric sheet functions as second piezoelectric layers 360a to 360d that generate and emit an ultrasonic signal by applying a voltage.

The second piezoelectric layers 360a to 360d may have a thickness R2 sufficient to generate an ultrasonic signal, and may have a length corresponding to the width and / or length of the receiver Rx.

In the present exemplary embodiment, the transmitter Tx includes one second piezoelectric layer 360a to 360d having a sufficient size to generate an ultrasonic signal corresponding to the entire area of the receiver Rx.

Referring to FIG. 10, ultrasonic signals S1, S2, ... having a predetermined resonance frequency f are shown in (a). The continuous ultrasound signal may be generated at regular intervals (T = 1 / f), and the resonance frequency of the ultrasound signal is related to the fingerprint recognition time at the receiver Rx.

In the present embodiment, K transmitters generating ultrasonic signals may be provided along the outer edge of the receiver Rx. In this case, the fingerprint recognition time at the receiver Rx can be shortened by 1 / K.

In the figure, a case in which four transmitters Tx1 to Tx4 (K = 4) is illustrated, which will be described below.

Referring to FIG. 10B, each of the ultrasonic signals S11 and S12, S21 and S22, S31 and S32, S41 and S42 generated by each of the transmitters Tx1 to Tx4 have a predetermined period T.

At this time, the generation time of the ultrasonic signal in each of the transmitters Tx1 to Tx4 may be divided and divided into T / 4 intervals within one period T. That is, at the first transmitter Tx1, at the first time point T1, at the second transmitter Tx2, at the second time point T1 + T / 4, and at the third transmitter Tx3, at the third time point T1 + 2T. 4), the fourth transmitter Tx4 may generate an ultrasonic signal at a fourth time point T1 + 3T / 4.

In this case, since four times more ultrasonic signals are generated during the same time T as compared with the conventional one, four times more signals can be received from the receiver Rx, thereby reducing the fingerprint recognition time. Or, by accepting four times as much information in the same time, the fingerprint recognition accuracy can be improved.

Although described above with reference to embodiments of the present invention, those of ordinary skill in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below It will be appreciated that it can be changed.

Claims

In the manufacturing method of the ultrasonic fingerprint sensor,

(a) manufacturing a first piezoelectric layer having a piezoelectric rod in the form of an m x n sensor array; And

(b) attaching a second piezoelectric layer in the form of one piezoelectric sheet to a lower portion of the first piezoelectric layer,

The first piezoelectric layer functions as a receiver of the ultrasonic fingerprint sensor and the second piezoelectric layer functions as a transmitter of the ultrasonic fingerprint sensor.
In the manufacturing method of the ultrasonic fingerprint sensor,

(a) manufacturing a first piezoelectric layer having a piezoelectric rod in the form of an m x n sensor array;

(b) attaching a rigid base substrate to the lower portion of the first piezoelectric layer; and

(c) attaching a second piezoelectric layer in the form of one piezoelectric sheet to side surfaces of the first piezoelectric layer and the base substrate,

The first piezoelectric layer functions as a receiver of the ultrasonic fingerprint sensor and the second piezoelectric layer functions as a transmitter of the ultrasonic fingerprint sensor.
The method according to claim 1 or 2,

Step (a) is,

(a1) preparing a first piezoelectric sheet which is a ceramic sintered body or composite piezoelectric material produced by a half sintering condition;

(a2) Dicing parallel to the first direction at predetermined intervals at a depth at which a remaining region remains on the second surface side on the first surface of the first piezoelectric sheet, and the first surface on the second surface. Dicing the substrate parallel to a second direction perpendicular to the first direction at a predetermined interval to a depth at which the remaining region remains on the side to form a ceramic workpiece, and sintering the ceramic workpiece under the conditions of complete sintering;

(a3) filling the grooves formed in the ceramic workpiece by the cutting process of step (a2);

(a4) removing the remaining regions respectively present on the first surface side and the second surface side such that the piezoelectric rods are arranged and exposed in an array form on the first surface and the second surface, respectively; Method of manufacturing the sensor.
The method according to claim 1 or 2,

Step (a) is,

(a1) providing a first piezoelectric sheet having a first metal layer formed on the first surface and having a second metal layer formed on a second surface not in contact with the first surface;

(a2) cutting the first metal layer and the piezoelectric sheet at predetermined intervals in parallel in a first direction;

(a3) filling the gap formed in the first piezoelectric sheet by the step (a2) with a predetermined insulating material;

(a4) cutting the first piezoelectric sheet and the second metal layer at predetermined intervals in parallel in a second direction orthogonal to a first direction; And

(a5) The manufacturing method of the ultrasonic fingerprint sensor comprising the step of filling the gap formed in the first piezoelectric sheet by a predetermined insulating material by the step (a4).
The ultrasonic fingerprint sensor manufactured by the manufacturing method of the ultrasonic fingerprint sensor in any one of Claims 1-5.
a receiver including a first piezoelectric layer having a piezoelectric rod in the form of an m x n sensor array; And

Including a transmitter including a second piezoelectric layer in the form of one piezoelectric sheet,

The transmitter is attached to the lower portion of the receiver,

The thickness of the second piezoelectric layer is greater than the thickness of the first piezoelectric layer, the ultrasonic fingerprint sensor.
a receiver including a first piezoelectric layer having a piezoelectric rod in the form of an m x n sensor array and a rigid base substrate attached to a lower portion of the first piezoelectric layer; And

At least one transmitter including a second piezoelectric layer in the form of one piezoelectric sheet,

The transmitter is attached to the side of the receiver,

And a thickness of the second piezoelectric layer corresponds to the sum of the thicknesses of the first piezoelectric layer and the base substrate.
The method according to claim 6 or 7,

And the first piezoelectric layer is formed using a ceramic sintered body or a composite piezoelectric material produced by an incomplete sintering condition.
The method according to claim 6 or 7,

The second piezoelectric layer is an ultrasonic fingerprint sensor, characterized in that the second piezoelectric sheet made of a sintered body.
The method of claim 7, wherein

If the transmitting unit is K,

The ultrasonic signal is divided into T / K intervals within one cycle T corresponding to the resonance frequency, and is sequentially generated in the K transmitters, thereby reducing the fingerprint recognition time at the receiver by 1 / K. Ultrasonic fingerprint sensor.