KR20140079254A - Fingerprint sensor package and manufacturing method therof - Google Patents

Abstract

An embodiment of the present invention provides a capacitive fingerprint sensor package comprising a fingerprint parent material including a base substrate and a sensor unit disposed on the base substrate; and a coating layer disposed on the fingerprint sensor parent material, wherein the coating layer is a ceramic coating layer containing ceramic.

Description

[0001] FINGERPRINT SENSOR PACKAGE AND MANUFACTURING METHOD THEROF [0002]

The present invention relates to a fingerprint sensor package and a manufacturing method thereof.

Background Art [0002] A fingerprint sensor is a sensor for detecting fingerprints of a human being and is widely used as a means for enhancing security in portable electronic devices such as a mobile terminal and a tablet PC. That is, the user is registered and authenticated through the fingerprint sensor, thereby protecting the data stored in the portable electronic device and preventing the security accident in advance.

On the other hand, in a portable electronic device, a navigation function for performing operation of a pointer such as a cursor is integrated into a fingerprint sensor. Such a fingerprint sensor is referred to as a biometric track pad (BTP). In addition, a switching function that receives information from a user may be incorporated into the fingerprint sensor.

There are capacitive type, optical type, ultrasonic type, thermal type, non-contact type, and the like. However, capacitive type fingerprint sensor having excellent sensitivity, robust against external environment change and excellent in compatibility with portable electronic devices, It is widely used.

In the case of a capacitive fingerprint sensor, there is a numerical limitation on the thickness at which the package or coating can proceed from the substrate plane in consideration of the operation of the sensor. That is, when the package or the coating is moved beyond a certain thickness in the capacitive fingerprint sensor, the sensor may be disabled due to a decrease in the strength of the fingerprint recognition signal and a loss. In order to avoid such a problem, that is, in order to secure the motion of the sensor, if the package or the coating is made thinner, a chip mark may be generated or a coating may not be partially or wholly formed.

Meanwhile, in order to mount the fingerprint sensor on various electronic devices, the fingerprint sensor is manufactured in the form of a package including peripheral parts and structures. In order to match the color of the fingerprint sensor with the color of the electronic device on which the fingerprint sensor package is mounted , Or for other reasons, it is necessary to implement colors on the base material of the fingerprint sensor including the fingerprint sensor.

For color implementation on such a base material of a fingerprint sensor, a method of painting using ultraviolet paint, ultraviolet (UV) vapor deposition or the like has been conventionally used. However, when hue is implemented on the base material of the fingerprint sensor by the conventional method, there arises a restriction that the interlayer structure and the thickness of the coating film must be properly ensured. If the coating film is not formed to a sufficient thickness, it is not only difficult to implement colors, but also increases the possibility of surface contamination, scratches, scratches, and the like on the fingerprint sensor. These damages adversely affect the image of the fingerprint sensed by the fingerprint sensor. An actual example thereof is well shown in the actual image of Fig.

On the other hand, in the case of a fingerprint sensor, in particular, an electrostatic-type fingerprint sensor, there is a change in the operation of the fingerprint sensor according to the thickness of the coating on the base material of the fingerprint sensor. In particular, as the thickness of the coating on the base material of the fingerprint sensor increases, the sensing response characteristic of the fingerprint sensor deteriorates, so that the thickness of the coating film that implements the color is limited.

As described above, when a coating film having a sufficient thickness is formed on the base material of the fingerprint sensor for color implementation, if the thickness of the coating film is reduced to such an extent that the fingerprint sensor is not damaged, There were technical contradictions such as difficulty in color implementation to a desired extent and poor abrasion resistance.

Meanwhile, a conventional method of forming a coating film on a base material of a fingerprint sensor by using a silk screen method has also been used. However, in this case, the thickness of the coating film can be made thin, while the problem of abrasion resistance and heat resistance is remarkably deteriorated there was.

It is an object of the present invention to provide a method of manufacturing a fingerprint sensor package that forms a thin coating layer on a fingerprint sensor base material capable of color implementation without deteriorating the operation of the fingerprint sensor, To provide a fingerprint sensor package manufactured by the method.

In order to achieve the above object, an embodiment of the present invention is a fingerprint sensor package of a capacitive type, comprising: a fingerprint sensor base material including a base substrate and a sensor unit provided on the base substrate to sense a fingerprint; And a coating layer provided on the base material of the fingerprint sensor, wherein the coating layer is a ceramic coating layer including ceramics.

In one embodiment of the present invention, the ceramic coating layer may have a predetermined permittivity depending on the driving frequency of the sensor unit, and may have colorability.

In one embodiment of the present invention, the thickness of the coating layer may be 15 to 40 탆.

In an embodiment of the present invention, the base material of the fingerprint sensor may further include an encapsulation portion covering the base substrate and the sensor portion, and the coating layer may be provided on the encapsulation portion.

In one embodiment of the present invention, the sealing portion may include a conductive polymer.

According to another aspect of the present invention, there is provided a method of manufacturing a capacitive fingerprint sensor package, including: forming a base substrate and a fingerprint sensor base material on the base substrate, ; And applying a ceramic coating layer including ceramics on the base material of the fingerprint sensor.

In one embodiment of the present invention, the ceramic coating layer may have a dielectric constant determined in advance according to a driving frequency of the sensor unit, and may be selected from a material having colorability.

In one embodiment of the present invention, the applying the ceramic coating layer comprises: preparing a ceramic coating; Preheating the fingerprint sensor base material; Spraying the ceramic paint onto the surface of the fingerprint sensor base material; And heat treating the fingerprint sensor base material to which the ceramic paint is sprayed.

In one embodiment of the present invention, the ceramic paint preparation step may include preparing a ceramic paint using a sol-gel method of producing a ceramic by stirring two or more solutions.

In one embodiment of the present invention, the base material of the fingerprint sensor further includes an encapsulation portion covering the base substrate and the sensor portion, and the ceramic coating layer may be applied on the encapsulation portion.

In one embodiment of the present invention, the sealing portion may include a conductive polymer.

According to an embodiment of the present invention, by applying a ceramic coating layer as a method of embodying colors on a base material of a fingerprint sensor, a thinner coating is realized while improving the operation of the fingerprint sensor.

In addition, according to one embodiment of the present invention, the surface mount technology (SMT) can be applied with excellent heat resistance of ceramic, thereby simplifying the process and reducing the cost.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is an actual image showing that the sensing characteristic deteriorates due to surface damage in a conventional fingerprint sensor.
2 is a schematic cross-sectional view of a fingerprint sensor package according to an embodiment of the present invention.
FIG. 3 is a schematic flowchart illustrating a manufacturing process of a fingerprint sensor package according to an embodiment of the present invention.
4 is a schematic view showing a process of preparing a ceramic paint by a sol-gel method.
5 is an image of a fingerprint measured using the fingerprint sensor package according to an embodiment of the present invention.
FIGS. 6 and 7 are diagrams showing changes in the fingerprint recognition signal in the embodiment and the comparative example of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "indirectly connected" . Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic cross-sectional view of a fingerprint sensor package according to an embodiment of the present invention.

As shown, the fingerprint sensor package 10 includes a fingerprint sensor base material 100 and a coating layer 200 provided on the fingerprint sensor base material. The fingerprint sensor base material 100 further includes a base substrate 110, a sensor unit 120 provided on the base substrate 110, a bonding wire 130 connecting the sensor unit 120 and the electrodes on the base substrate 110, And an encapsulation unit 140 covering the surface of the base substrate 110 and the sensor unit 120.

The fingerprint sensor package 10 may be provided in an electronic device, in particular, a portable electronic device. It should be understood that the portable electronic device includes any portable electronic device such as a mobile phone, a smart phone, a PDA, a tablet PC, a notebook computer, a portable sound recorder (MP3 player), and the like.

Referring again to FIG. 2, the base substrate 110 is a substrate on which a sensor unit 120 or the like described below is mounted, and electric signal information is transmitted. The base substrate 110 may be, for example, a printed circuit board (PCB) or a flexible printed circuit (FPC). Although not shown, a lead frame may be attached to a lower portion of the base substrate 110 by resin injection or surface mounting technology (SMT).

The sensor unit 120 is provided on the base substrate 110 to detect a fingerprint. That is, the sensor unit 120 may be a fingerprint sensor, and may be a biometric trackpad (BTP) having a fingerprint detection function and a pointer operation function at the same time.

Specifically, the sensor unit 120 is a capacitive type fingerprint sensor that senses whether a user's finger, which is a subject, is approaching or changes in capacitance due to the movement, and detects a pointer such as a cursor based on the movement of the sensed finger And may include a moving pointer manipulation function.

In addition, the sensor unit 120 may include an input function for receiving information or commands desired by the user. For example, the sensor unit 120 may be integrally or separately provided with a dome switch used for selecting a menu or an icon pointed to.

The sensor unit 120 basically has a fingerprint detection function. To this end, the sensor unit 120 may store information on the minutiae of the fingerprint (for example, the fingerprint fragments such as the 'Y' point) separately, and compare the minutiae to detect fingerprint matching have. In this case, the time taken to detect the fingerprint can be shortened, and the miniaturization can be achieved through simplification of the processor, so that the mountability to the electronic apparatus can be improved.

The sensor unit 120 may be implemented as a slide type. That is, the sensor unit 120 senses fingerprints of a finger moving in a sliding manner, reads fragmentary fingerprint images, and registers the fingerprint images as a single image to implement a full fingerprint image. can do. A fingerprint sensor employing such a sensor unit 120 may also be referred to as a " bar-shaped "or" straight fingerprint sensor "

Meanwhile, the sensor unit 120 may be mounted on the base substrate 110 by, for example, epoxy bonding.

The bonding wire 130 electrically connects an electrode (not shown) on the sensor unit 120 and an electrode (not shown) on the base substrate 110. With this electrical connection configuration, a drive signal can be sent toward the user's finger, and fingerprint information of the user's finger can be received in response to the transmitted drive signal. The bonding wire 130 may be, for example, a gold wire, but is not limited to such a material. Although the electrical connection through the bonding wire 130 is illustrated as an example in the present embodiment, it is also possible to electrically connect the sensor unit 120 and the base substrate 110 without passing through the bonding wire 130. For example, the sensor unit 120 can be electrically connected to the base substrate 110 directly via an electrode provided at the lower end of the sensor unit 120 (see FIGS. 6 and 7).

The sealing portion 140 is a component that seals (covers) the base substrate 110 and the sensor portion 120, and protects various electrical components. The sealing part 140 may be, for example, an epoxy molding compound. The material of the sealing portion 140 such as an epoxy molding compound is well known and will not be described in detail.

Meanwhile, a bezel may be provided on the side surface of the sensor unit 120 (refer to reference numeral 150 in FIGS. 6 and 7). The bezel may also serve as an electrode transmission unit for transmitting the driving signal.

Alternatively, as shown in FIG. 2, it is also possible to configure the fingerprint sensor package 10 in a form without a bezel. In this case, the sealing portion 140 itself may have a function as an electrode transmitting portion for transmitting a driving signal have. For this purpose, the encapsulating part 140 may include a conductive polymer.

Next, a coating layer 200 is provided on the base material 100 of the fingerprint sensor.

The coating layer 200 may be a ceramic coating layer including ceramics, and the thickness of the coating layer 200 may be 15 to 40 占 퐉. If the thickness of the coating layer 200 is less than 15 탆, the effect of color rendering may not be exhibited, and the wear resistance and heat resistance are not sufficiently ensured. In addition, when the thickness of the coating layer 200 is larger than 40 mu m, the sensor unit 120 can not receive a signal for the fingerprint image smoothly. That is, the operation of the fingerprint sensor deteriorates.

The coating layer 200 has a function as a dielectric layer. At this time, the dielectric constant of the coating layer 200 may be determined in advance according to the driving frequency of the sensor unit 120. More specifically, when the finger of the user touches the fingerprint sensor package 10 or when the user's finger sufficiently approaches the fingerprint sensor package 10 to such a degree that fingerprint recognition is possible, Is received by the image sensing area provided on the surface of the sensor unit 120 via the user. When using a dielectric layer having a dielectric constant suitable for the driving frequency of the sensor portion 120 (i.e., the coating layer 200), the signal becomes more concentrated in the dielectric layer and is received in the image sensing region. Therefore, the loss of the signal is reduced and the operation of the sensor unit 120 is improved. Details thereof will be described later.

As described above, in the embodiment of the present invention, the ceramic coating layer 200 is formed on the base material 100 of the fingerprint sensor, thereby achieving various colors, lower film thickness, abrasion resistance and heat resistance, The signal loss of the fingerprint sensor can be reduced and the operation can be improved. A more detailed description, including the effect of the ceramic coating layer 200, will be provided in connection with the method of manufacturing the fingerprint sensor package.

Next, a method of manufacturing a fingerprint sensor package according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic cross-sectional view of a fingerprint sensor package according to an embodiment of the present invention, and FIG. 3 is a schematic flowchart illustrating a manufacturing process of a fingerprint sensor package according to an embodiment of the present invention.

As shown in FIG. 2, the method of manufacturing a fingerprint sensor package includes steps (S10) of providing a fingerprint sensor base material, and steps (S20 to S50) of applying a ceramic coating layer containing ceramic on the fingerprint sensor base material .

First, a step (S10) of preparing a base material for a fingerprint sensor will be described. The fingerprint sensor base material 100 includes a base substrate 110 and a sensor unit 120 provided on the base substrate 110 to sense a fingerprint (see FIG. 2).

The fingerprint sensor base material 100 may further include an encapsulation unit 140 covering the base substrate 110 and the sensor unit 120. In this case, the ceramic coating layer 200 is applied on the encapsulation unit 140 2). In addition, the sealing portion 140 may include a conductive polymer. Since the configuration of the fingerprint sensor base material 100 has been described above, redundant description will be omitted.

Next, steps (S20 to S50) of applying a ceramic coating layer containing ceramic on the base material of the fingerprint sensor will be described.

First, a ceramic paint is prepared (S20). The ceramic paint can be prepared, for example, by using a sol-gel method in which two or more solutions are stirred to produce a ceramic.

The preparation process of the ceramic paint using the sol-gel method is schematically shown in Fig. The sol-gel method of the two-pack type paint will be described with reference to FIG. 4. First, the liquid A and the liquid B are prepared (a) and the liquid A is shaken up, down, left and right for a predetermined time (for example, 30 minutes) Next, the liquid B is mixed with the liquid A and stirred for a predetermined time (for example, 5 hours) (c). If a two-component ceramic paint is formed by this process, it should be used after being sufficiently shaken before application (spraying) (d).

Next, the fingerprint sensor base material is preheated (S30). Although not shown, the fingerprint sensor substrate may be subjected to an inspection process, a contamination removal process such as oil, a drying process, a sand blast process, a cleaning process, and the like before step S30. The detailed description thereof is omitted because it goes beyond the scope of the present invention.

Next, the prepared ceramic paint is sprayed on the surface of the base material of the fingerprint sensor (S40). Although not shown, an air blowing process may be performed before step S40, but a detailed description thereof will be omitted.

The ceramic coating material may be prepared by, for example, a sol-gel method as described above, and a ceramic coating layer may be formed on the base material of the fingerprint sensor to a thickness of 15 to 40 탆 by using the ceramic coating material.

The ceramics have a high permittivity, which reduces the loss of the signal that the image sensor accepts in the active state of the fingerprint sensor. As a result, the thickness of the coating film (coating layer) can be more freely implemented. In addition, ceramics have high stain resistance such as anti-fingerprint and water repellency. Therefore, it is possible to obtain more clear fingerprint images by reducing image blurring due to surface contamination. In addition, it is possible to realize various colors by blending an inorganic pigment excellent in heat resistance, hiding power and weather resistance in the ceramic paint.

Finally, the fingerprint sensor base material having the ceramic paint sprayed thereon is heat-treated (S50) to complete the manufacture of the fingerprint sensor package.

5 is an image of a fingerprint measured using the fingerprint sensor package according to an embodiment of the present invention. 5 and FIG. 1, it can be seen that the fingerprint sensor package according to the embodiment of the present invention can actually obtain clearer fingerprint images.

FIGS. 6 and 7 are diagrams showing changes in the fingerprint recognition signal in the embodiment and the comparative example of the present invention. In the comparative example, the same or similar reference numerals are given to the same or similar components as in the embodiment of the present invention.

6 (a) shows a fingerprint sensor package 10 'as a comparative example in comparison with an embodiment of the present invention, and FIG. 6 (b) shows a fingerprint sensor package 10' according to an embodiment of the present invention. The package 10 is shown. In the fingerprint sensor package 10 'of the comparative example, a package portion 140' is formed on the base substrate 110 and the sensor portion 120. The package portion 140 'includes a sealing portion and a coating layer on the upper side of the sealing portion. The thickness of the package portion 140' is determined by the thickness of the sealing portion 140 and the coating layer 200 according to an embodiment of the present invention. Is generally larger than the thickness of the combined area. The bezel 150 is provided on the sides of the sensor unit 120 and the package unit 140 '. The bezel 150 determines the appearance of the fingerprint sensor package 10 'and has a function of an electrode transmitting portion for transmitting a driving signal to the user's finger 20. [

In FIG. 6, reference numerals 300 and 300 'denote electric lines of force by an electric field (electric field) acting on the user's finger 20 or the outside through the bezel 150. The portion indicated by the solid line in the electric force lines 300 and 300 'represents an electric line of force directed to the sensor portion 120 through the user's finger 20 and the portion indicated by the dotted line indicates the outward It shows an electric line of force. That is, the electric line indicated by the dotted line corresponds to the loss of the signal.

6 (a) and 6 (b), in the embodiment of the present invention (FIG. 6 (b)), since the coating layer 200 including ceramics acts as a dielectric layer, An electric line of force directed toward the sensor unit 120 is formed more densely than an electric force line 300 (indicated by a dotted line) directed to the outside in comparison with the example (FIG. 6A). That is, in the fingerprint sensor package 10 according to the embodiment of the present invention, loss of the electric field is reduced.

This fact can be confirmed also in Fig. 7 (a) shows a fingerprint sensor package 10 'as a comparative example in comparison with an embodiment of the present invention, and FIG. 7 (b) shows a fingerprint sensor package 10' according to an embodiment of the present invention. 10 are shown.

7, the base substrate 110 and the bezel 150 are electrically connected by the first electrode 160a, and the base substrate 110 and the sensor unit 120 are electrically connected to each other by the second electrode 160b . For reference, although the base substrate 110 and the sensor unit 120 are electrically connected to each other by the bonding wire 130 (see FIG. 2) in the above embodiment, It is also possible that the base substrate 110 and the sensor unit 120 are electrically connected to each other by the second electrode 160b as shown in FIG.

Reference numerals 400 and 400 'in FIG. 7 denote image sensing areas of the sensor unit 120 through the sensor unit 120, the base substrate 110, the bezel 150, and the user's finger (not shown) ) 120a, respectively. Here, the thickness of the sensing signal 400 (400 ') means the intensity of the signal.

7A and 7B, in the embodiment of the present invention (FIG. 7B), the coating layer 200 as the dielectric layer is placed on the sealing portion 140 , So that the loss of the sensing signal 400 is reduced as compared with the comparative example (FIG. 7A) in which the dielectric layer is not present. That is, the intensity of the signal is reduced in proportion to the thickness of the package of the sensing signal 400. In the fingerprint sensor package 10 according to the embodiment of the present invention, a dielectric suitable for the capacitance frequency of the sensor can be used , The loss of the signal is reduced. Therefore, the operation of the fingerprint sensor is improved.

As described above, according to the embodiment of the present invention, by applying the ceramic coating layer capable of realizing colors on the base material of the fingerprint sensor, it is possible to improve the operability and quality of the fingerprint sensor while forming a thinner coating film.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

10: fingerprint sensor package
100: fingerprint sensor base material
110: Base substrate
120: Fingerprint sensor
130: bonding wire
140:
200: Coating layer

Claims (11)

A capacitive fingerprint sensor package comprising:
A base substrate, and a sensor unit provided on the base substrate and sensing a fingerprint; And
And a coating layer provided on the base material of the fingerprint sensor,
Wherein the coating layer is a ceramic coating layer including ceramics. The method according to claim 1,
Wherein the ceramic coating layer has a dielectric constant predetermined in accordance with a driving frequency of the sensor unit and has a coloring property. The method according to claim 1,
Wherein the thickness of the coating layer is 15 to 40 占 퐉. The method according to claim 1,
Wherein the fingerprint sensor base material further comprises an encapsulation portion covering the base substrate and the sensor portion, and the coating layer is provided on the encapsulation portion. 5. The method of claim 4,
Wherein the sealing portion comprises a conductive polymer. A method of manufacturing a capacitive fingerprint sensor package,
Providing a base material for a fingerprint sensor including a base substrate and a sensor unit provided on the base substrate and sensing a fingerprint; And
Further comprising the step of applying a ceramic coating layer including ceramics on the base material of the fingerprint sensor. The method according to claim 6,
Wherein the ceramic coating layer has a predetermined dielectric constant according to a driving frequency of the sensor unit and is selected from a material having colorability. The method according to claim 6,
The step of applying the ceramic coating layer comprises:
Preparing a ceramic paint;
Preheating the fingerprint sensor base material;
Spraying the ceramic paint onto the surface of the fingerprint sensor base material; And
And thermally treating the fingerprint sensor base material on which the ceramic paint is sprayed. 9. The method of claim 8,
Wherein the ceramic paint preparation step comprises preparing a ceramic paint using a sol-gel method for producing a ceramic by stirring two or more solutions. The method according to claim 6,
Wherein the fingerprint sensor base material further comprises an encapsulation portion covering the base substrate and the sensor portion, and the ceramic coating layer is applied on the encapsulation portion. 11. The method of claim 10,
Wherein the sealing portion comprises a conductive polymer.

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