KR20060114429A - Finger print sensing apparatus having directly contacted pixel array of image sonsor and contact emitting sensor - Google Patents

Abstract

A finger print sensing device having a pixel array of an image sensor directly contacted with a contact emitting sensor is provided to overcome refraction and difficulty in miniaturization by a lens inserted between the contact emitting sensor and the CMOS(Complementary Metal Oxide Semiconductor) image sensor. The contact emitting sensor(41) outputs different optical signals according to a ridge and a valley of a contacted fingerprint by using AC power. The image sensor(40) makes the pixel array directly contacted with a light output surface of the contact emitting sensor, and outputs an electric signal by receiving and converting the optical signal. Each adhesive layer(42,51) adheres the contact emitting sensor to the image sensor. A PCB(Printed Circuit Board)(47) mounts the image sensor. A lead attached to the PCB surrounds the contact emitting sensor and the image sensor to package the contact emitting sensor and the image sensor as a cavity type.

Description

FINGER PRINT SENSING APPARATUS HAVING DIRECTLY CONTACTED PIXEL ARRAY OF IMAGE SONSOR AND CONTACT EMITTING SENSOR}

1 is a view schematically showing a fingerprint recognition device according to the prior art.

FIG. 2 is a cross-sectional view of the contact light emitting sensor of FIG. 1 in more detail. FIG.

3 is a cross-sectional view showing a state in which a fingerprint is recognized by the touch light emitting sensor.

Figure 4 is a cross-sectional view schematically showing a fingerprint recognition device according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of the fingerprint sensing device of FIG. 4 in more detail, showing a packaged state. FIG.

6 is a plan view of the fingerprint sensing device shown in FIG.

7 is a flow chart schematically illustrating a manufacturing process of the fingerprint sensing device.

FIG. 8 is a cross-sectional view of the fingerprint sensing device of FIG. 4 in more detail, showing another package form. FIG.

9 is a plan view of the fingerprint sensing device shown in FIG.

FIG. 10 is a flowchart schematically illustrating a manufacturing process of the fingerprint sensing device. FIG.

Explanation of symbols on the main parts of the drawings

40: image sensor 41: contact light emitting sensor

47: PCB substrate 42, 51, 53: adhesive layer

49: AC voltage supply unit 50: Cavity type package

52: leadframe

The present invention relates to a fingerprint recognition device, and more particularly, to a fingerprint recognition device using a touch light emitting device and a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

Currently, the fingerprint recognition device is largely divided into a chip-based sensor using an optical and semiconductor application technology using a lens or a prism, but its weight is inclined toward the chip-based sensor. In comparison, they have a significant advantage.

If the current trend that focuses on the portable function, the authentication sensor requires a light and simple sensor, so the fingerprint recognition device using the contact light emitting device and the image sensor will be widely used.

1 is a view schematically showing a fingerprint recognition device according to the prior art.

Referring to FIG. 1, a conventional fingerprint recognition device includes a lens for condensing light 14 output from a contact light emitting sensor 12 and a light emitting sensor 12 that emits light through a contact surface when a fingerprint is touched ( 11) and an image sensor 10 that receives the light 15 collected through the lens and outputs an electrical signal corresponding thereto through photoelectric conversion.

That is, the fingerprint recognition device outputs an optical signal corresponding to the fingerprint ridge 13 having a different shape for each person through the contact light emitting sensor 12 which outputs light from the contacted portion when the fingerprint is contacted. Is collected through the lens 11 and the collected light 15 is received by the image sensor 10.

The image sensor 11 outputs an electrical signal corresponding to an optical signal through a photoelectric conversion process, and recognizes a fingerprint through the electrical signal.

2 is a cross-sectional view of the contact light emitting sensor 12 of FIG. 1 in more detail.

Referring to FIG. 2, the touch light emitting sensor 12 selectively emits light at a portion corresponding to a contact surface according to a protective layer 22 located at a portion where a user's fingerprint is in contact with the fingerprint. Emitting layer (21) for the purpose, the transparent electrode 20 made of a transparent material to output the light output from the light emitting layer 21 to the bottom, and the insulating layer 23 surrounding the protective layer 22 and the light emitting layer 21 And an electrode 24a and 24b connecting the alternating current power source 25 to the finger and the transparent electrode 20 so that a current flows through the contacting finger and the transparent electrode 20.

On the other hand, between the light emitting layer 21 and the protective layer 22, but there is a light shielding layer, a dielectric layer, etc., it is omitted here for the sake of simplicity, the transparent electrode 20 is usually composed of a transparent electrode layer and a transparent substrate.

The light emitting sensor 12 having the above-described structure generates an optical signal in the light emitting layer 21 when a fingerprint is touched while AC is applied through the AC power supply 25.

In the light emitting layer 21, a large number of emitting particles are present therein. That is, the emission layer 21 is formed of a host material and atoms doped therein, and in the vicinity of the doped atoms, numerous electrons are trapped at a trap level. The trap level is located near the conduction band between the conduction band and the valence band.

Thus, when an electric field is applied, the electrons in the conduction band gain energy, are excited, and then trapped at the trap level and emit light as the ground state.

3 is a cross-sectional view illustrating a state in which a fingerprint is recognized by the touch light emitting sensor.

Referring to FIG. 3, when the fingerprint ridge 26 is in contact with the upper portion of the light emitting layer 21, the intensity of the electric field flowing through the light emitting layer 21 is changed along the ridge, and the optical signal 27 also appears differently in proportion thereto. Fingerprint ridge 26 is composed of the valleys (V) and the floor (E) of the fingerprint bar, because the distribution of the valleys (V) and floor (E) of the fingerprint varies from person to person, such valleys (V) and floor (E). ) And the optical signal 27 proportional to the intensity of the electric field distributed differently according to the output.

In the structure of FIG. 1, the image sensor 10 receives a light signal 15, 27 output from the contact light emitting sensor 12 and collected by the lens 11, and converts an electric signal.

However, in the conventional fingerprint recognition device having the structure of FIG. 1, since the lens 11 is inserted between the image sensor 10 and the contact light emitting sensor 12, it is difficult to focus the lens 11. In addition, light may be diffracted by the spaced distance, and the size of the fingerprint recognition device increases by the height of the lens 11.

Therefore, the conventional fingerprint recognition device having the above-described structure is practically impossible to apply in a portable device where the miniaturization of accuracy and size is essential.

The present invention proposed to solve the problems of the prior art as described above is to provide a fingerprint recognition device that can overcome the difficulty of diffraction and miniaturization of light due to the lens inserted between the contact light emitting sensor and the image sensor. have.

In order to achieve the above object, the present invention provides a contact light emitting sensor for outputting different optical signals according to the valleys and the floor of the fingerprint contacted by the AC power source; An image sensor in direct contact with the light emitting surface of the contact light emitting sensor and a pixel array, for receiving the optical signal and outputting an electrical signal through photoelectric conversion; An adhesive layer for bonding the contact light emitting sensor to the image sensor; A PCB substrate bonded to the image sensor; And a lead attached to the PCB substrate while surrounding the contact light sensor and the image sensor to package the contact light sensor and the image sensor in the form of a cavity.

In addition, the present invention provides a contact light emitting sensor for outputting different optical signals according to the valley and the floor of the fingerprint that is contacted by the AC power source; An image sensor in direct contact with the light emitting surface of the contact light emitting sensor and a pixel array, for receiving the optical signal and outputting an electrical signal through photoelectric conversion; An adhesive layer for bonding the contact light emitting sensor to the image sensor; A lead frame disposed under the image sensor; And a lid attached to the lead frame while surrounding the contact light emitting sensor and the image sensor to package the contact light emitting sensor and the image sensor in the form of a cavity.

According to the present invention, instead of removing the lens inserted between the image sensor and the contact light emitting sensor in the structure of the conventional fingerprint recognition device, the pixel array portion of the contact light emitting sensor and the image sensor is disposed to be in direct contact with each other. The problem of the increase and the diffraction of light due to the separation of the contact light emitting sensor and the image sensor is to be solved.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention.

4 is a cross-sectional view schematically showing a fingerprint recognition device according to an embodiment of the present invention.

Referring to Figure 4, the fingerprint recognition device according to an embodiment of the present invention, the contact light emitting sensor 41 and outputs a different light signal according to the valley and the floor of the fingerprint that is contacted by the AC power source, the contact light emitting sensor ( The light emitting surface of the 41 and the pixel array 400 is in direct contact with each other, the image sensor 40 for receiving an optical signal and outputting an electrical signal through photoelectric conversion, the contact light emitting sensor 41 and the image sensor 40 It comprises a bonding layer 42 for bonding the.

The image sensor 40 includes a pixel array 400 including a plurality of unit pixels and a signal processor 43 for processing an electrical signal provided from the pixel array 400.

The fingerprint recognition device having the above-described configuration reads a fingerprint ridge 44 having a different shape for each person through a contact light emitting sensor 41 which outputs light at the portion in contact when the fingerprint is contacted, and then the fingerprint ridge ( The image sensor 40 outputs an optical signal corresponding to 44 and the light emitting surface of the contact light emitting sensor 41 and the pixel array 400 directly receive the optical signal, and then receives the optical signal through a photoelectric conversion process. An electrical signal corresponding to the output is output, and the fingerprint is recognized through the electrical signal.

According to the present invention, the light emitting surface of the touch light emitting sensor 41 and the pixel array 400 are in direct contact with each other, thereby removing the lens disposed between the touch light emitting sensor 41 and the pixel array 400, thereby increasing the volume increase problem due to the lens. I can solve it.

In addition, since the light emitting surface of the contact light emitting sensor 41 and the pixel array 400 are in direct contact with each other, there is no space between the two, thereby solving the problem due to diffraction of light.

FIG. 5 is a cross-sectional view of the fingerprint sensing device of FIG. 4 in more detail, showing a packaged state. FIG.

Referring to FIG. 5, an image sensor 40 is disposed on a PCB board 47, and the image sensor 40 is in direct contact with the pixel array portion of the image sensor 40 via an adhesive layer 42. The light emission sensor 41 is arrange | positioned.

The electrodes on the side of the image sensor 40 and the contact light emitting sensor 41 are wire bonded 46, and the electrodes of the contact light emitting sensor 41 are interconnected through an AC power supply 49 and the upper electrode 45a. The open part 48 is formed on the upper surface of the contact light emitting sensor 41 on the side of the upper electrode 45a so as to make fingerprint contact. The electrodes are all formed through metal lines.

On the other hand, the image sensor 40 and the contact light emitting sensor 41 is surrounded by the package 50 of the cavity (Cabity) form. The cavity-type package and the PCB substrate are bonded by the adhesive material 51. A cavity type package refers to a package in which an empty space is left without molding the inside.

The fingerprint sensing device according to the present embodiment does not use a package of a lead frame and a molding type, but uses a method of directly adhering to a cavity-type package and a PCB substrate which are empty inside. Since it is directly bonded to the PCB substrate, there is an advantage that can directly send and receive signals with the PCB substrate without using a lead frame, there is an advantage that can be manufactured in a small size.

FIG. 6 is a plan view of the fingerprint sensing device shown in FIG. 5.

Referring to FIG. 6, a PCB substrate 47 is positioned at the bottom thereof, and an image sensor 40 and a contact light emitting element 41 are connected to a pad, an electrode, etc. through wire bonding 46, and contacted thereon. The upper portion of the light emitting element 41 is formed with an open portion 48.

FIG. 7 is a flow chart schematically illustrating the manufacturing process of the fingerprint sensing device, and looks at the manufacturing process of the fingerprint sensing device with reference to the flowchart.

First, die bonding (S701) is performed. At this time, PCB substrate and CMOS image sensor are attached.

Subsequently, the pixel array of the image sensor and the contact light emitting sensor are directly adhered using the adhesive layer (S702).

Subsequently, wire bonding is performed (S703), a lead (Lid) for making a cavity-type package is attached (S704), and the metal line and the contact light emitting sensor are connected to each other so that AC power can be applied (S705).

According to the present invention made as described above, instead of removing the lens inserted between the image sensor and the contact light emitting sensor in the structure of the conventional fingerprint recognition device, by placing the pixel array portion of the contact light emitting sensor and the image sensor in direct contact In the present invention, the problem of the size increase due to the lens and the light diffraction due to the separation between the contact light emitting sensor and the image sensor can be solved through the examples.

In the above-described embodiment, a method of directly attaching to a PCB substrate without using a lead frame when packaging is provided. In the present invention, a lead frame is used, but without using a molding method used in a general package, and a cavity type. Further suggest how to use the package.

FIG. 8 is a cross-sectional view illustrating the fingerprint sensing device of FIG. 4 in more detail, and showing another package form.

Referring to FIG. 8, in the fingerprint sensor further proposed in the present invention, the image sensor 40 is disposed on the lead frame 52, and the image sensor 40 is formed on the image sensor 40 via the adhesive layer 42. A contact light emitting sensor 41 in direct contact with the pixel array portion of 40 is disposed.

The electrode 45b on the side of the image sensor 40 and the contact light emitting sensor 41 is wire-bonded 46, and the electrodes of the contact light emitting sensor 41 are interconnected through the AC power source 49 and the upper electrode. An open portion 48 is formed on the upper surface of the contact light emitting sensor 41 of the upper electrode side to allow fingerprint contact. The electrodes are all formed through metal lines.

On the other hand, the image sensor 40 and the contact light emitting sensor 41 is surrounded by the package 50 of the cavity (Cabity) form. The package in the form of a cavity is bonded by an adhesive material 53. A cavity type package refers to a package in which an empty space is left without molding the inside.

The fingerprint sensing device according to the present exemplary embodiment uses a cavity-type package and a lead frame method without using a molded package, but a cavity inside.

9 is a plan view of the fingerprint sensing device shown in FIG.

Referring to FIG. 9, the lead frame 52 is positioned at the bottom thereof, and the image sensor 40 and the contact light emitting device 41 are connected to the pad, the electrode, and the like through the wire bonding 46, respectively. The upper portion of the light emitting element 41 is formed with an open portion 48.

FIG. 10 is a flow chart schematically illustrating the manufacturing process of the fingerprint sensing device, and looks at the manufacturing process of the fingerprint sensing device with reference thereto.

First, die bonding is performed. At this time, the lead frame and CMOS image sensor are attached.

Subsequently, the adhesive layer is used to directly adhere the pixel array of the image sensor to the contact light emitting sensor.

Subsequently, wire bonding is performed, and a lead Lid for making a cavity-type package is attached (S704), and the metal line and the contact light emitting sensor are connected so that AC power can be applied (S705).

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

For example, a CMOS image sensor, a CCD, and all image sensors may be used as the image sensor applied in the above-described embodiment.

The present invention described above has the effect of reducing the size of the fingerprint sensing device to be applied to a portable device and at the same time reducing the deterioration of characteristics due to diffraction or the like, thereby improving its performance.

Claims (6)

A contact light emitting sensor for outputting different optical signals according to the valleys and the floors of the fingerprint contacted by the AC power; An image sensor in direct contact with the light emitting surface of the contact light emitting sensor and a pixel array, for receiving the optical signal and outputting an electrical signal through photoelectric conversion; An adhesive layer for bonding the contact light emitting sensor to the image sensor; A PCB substrate bonded to the image sensor; And And a lid attached to the PCB substrate while surrounding the contact light emitting sensor and the image sensor to package the contact light emitting sensor and the image sensor in the form of a cavity. The method of claim 1, The touch light emitting sensor is a fingerprint sensing device, characterized in that the top portion has an open portion for fingerprint contact. The method according to claim 1 or 2, The touch light emitting sensor is a fingerprint sensing device, characterized in that connected to the AC power through the wire bonding. A contact light emitting sensor for outputting different optical signals according to the valleys and the floors of the fingerprint contacted by the AC power; An image sensor in direct contact with the light emitting surface of the contact light emitting sensor and a pixel array, for receiving the optical signal and outputting an electrical signal through photoelectric conversion; An adhesive layer for bonding the contact light emitting sensor to the image sensor; A lead frame disposed under the image sensor; And A lead attached to the lead frame surrounding the contact light emitting sensor and the image sensor to package the contact light emitting sensor and the image sensor in the form of a cavity; Fingerprint sensing device comprising a. The method of claim 4, wherein The touch light emitting sensor is a fingerprint sensing device, characterized in that the top portion has an open portion for fingerprint contact. The method according to claim 4 or 5, The touch light emitting sensor is a fingerprint sensing device, characterized in that connected to the AC power through the wire bonding.

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