OPTICAL FINGERPRINT SENSOR PACKAGE

Abstract

An optical fingerprint sensor package includes a carrier, an image sensor, at least one LED (light emitting diode), and a molding compound. The carrier is penetrated with a first cavity. The carrier has a peripheral region surrounding the first cavity. The peripheral region is provided with first conductive pads thereon. The image sensor is mounted in the first cavity and electrically connected to the first conductive pads by conductive wire bonding. The LED is mounted to correspond to the peripheral region of the carrier. The molding compound covers the peripheral region of the carrier, the image sensor, and the at least one LED, and fills the first cavity to fix the image sensor in the first cavity and expose the bottom of the image sensor to an external space.

Description

REFERENCE TO RELATED APPLICATION

This Application is based on U.S. Provisional Application Ser. No. 62/425,715, filed 23 Nov. 2016.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a package structure, particularly to an optical fingerprint sensor package.

Description of the Related Art

Typically, fingerprints have a number of features including ridges, valleys, and finer points. A finer point includes a bifurcation where a ridge is branched and an end point where the ridge ends. The fingerprint can be regarded as a unique biometric data since its characteristic distribution is different every person and two people cannot have the same fingerprints. Thus, the use of biometric data such as fingerprints in a security system may ensure efficient and accurate protection for the district that requires security, movable assets or the like.

A fingerprint recognition apparatus for acquiring an image of the fingerprint may be classified into a semiconductor type apparatus and optical type apparatus, and an optical fingerprint recognition apparatus is widely used rather than a semiconductor fingerprint recognition apparatus. The optical fingerprint recognition apparatus includes light sources, an image sensor and a total internal reflection prism glass in which light proceeds through the incident surface of the prism, is reflected at the contact surface of the prism, and is emitted from the exit surface of the prism. When a finger is put on the contact surface of the prism, light undergoes diffused reflectance at the points where the ridges of the fingerprint are in contact with the glass. However, no light undergoes the diffused reflectance at the points where the valleys of the fingerprint are in contact with the glass. Thus, the light emitted from the exit surface of the prism exhibits the characteristics of the fingerprint. Refer to FIG. 1. The conventional optical fingerprint recognition package includes a supporting base 10, an isolated base 12, a first adhesive 14, a second adhesive 16, LEDs 18, an image sensor 20, and a transparent colloid 22. The isolated base 12 is located in the supporting base 10. The LEDs 18 are located on the isolated base 12 through the first adhesive 14. The image sensor 20 is located on the supporting base 10 through the second adhesive 16. The transparent colloid 22 is located in the supporting base 10 to cover the isolated base 12, the first adhesive 14, the second adhesive 16, the LEDs 18, and the image sensor 20. However, due to the existence of the supporting base 10, the whole volume of the conventional optical fingerprint recognition package is larger. As a result, the conventional optical fingerprint recognition package is difficultly embedded in a panel or a glass cover.

To overcome the abovementioned problems, the present invention provides an optical fingerprint sensor package.

SUMMARY OF THE INVENTION

A primary objective of the present invention is to provide an optical fingerprint sensor package, which penetrates a carrier to form a cavity and places an image sensor in the cavity to decrease the thickness and volume of the optical fingerprint sensor package.

To achieve the abovementioned objectives, the present invention provides an optical fingerprint sensor package, which comprises a carrier, an image sensor, at least one LED (light emitting diode), and a molding compound. The carrier is penetrated with a first cavity. The carrier has a peripheral region surrounding the first cavity. The peripheral region is provided with first conductive pads thereon. The image sensor is mounted in the first cavity and electrically connected to the first conductive pads by conductive wire bonding. The LED is mounted to correspond to the peripheral region of the carrier. The molding compound covers the peripheral region of the carrier, the image sensor, and the at least one LED, and fills the first cavity to fix the image sensor in the first cavity and expose the bottom of the image sensor to an external space.

In an embodiment of the present invention, the at least one LED is mounted on the peripheral region of the carrier through an adhesive by surface-mount technology (SMT).

In an embodiment of the present invention, the adhesive is a red glue or a silver paste.

In an embodiment of the present invention, the height of the bottom of the at least one LED is higher than the height of the top of the image sensor.

In an embodiment of the present invention, the peripheral region of the carrier is further provided with second conductive pads thereon and penetrated with at least one second cavity. The at least one LED is mounted in the at least one second cavity of the peripheral region, the molding compound fills the at least one second cavity to fix the at least one LED in the at least one second cavity and expose the bottom of the at least one LED to the external space. The at least one LED is electrically connected to the second conductive pads by conductive wire bonding.

In an embodiment of the present invention, the at least one second cavity further comprises a plurality of second cavities, and the at least one LED further comprises a plurality of LEDs (light emitting diodes) respectively mounted in the plurality of second cavities.

In an embodiment of the present invention, the height of the top of the carrier is higher than the height of the top of the at least one LED.

In an embodiment of the present invention, the carrier is a substrate or a lead frame.

In an embodiment of the present invention, the at least one LED comprises a plurality of LEDs (light emitting diodes).

In an embodiment of the present invention, the at least one LED is an infrared (IR) LED.

In an embodiment of the present invention, the image sensor is a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS).

Below, the embodiments are described in detail in cooperation with the drawings to make easily understood the technical contents, characteristics and accomplishments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an optical fingerprint sensor package in the conventional technology;

FIG. 2 is a top view of an optical fingerprint sensor package according to the first embodiment of the present invention;

FIG. 3 is a sectional view taken along Line A-A′ of FIG. 2;

FIG. 4 is a top view of the optical fingerprint sensor package according to the second embodiment of the present invention; and

FIG. 5 is a sectional view taken along Line B-B′ of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. In the drawings, the shape and thickness may be exaggerated for clarity and convenience. This description will be directed in particular to elements forming part of, or cooperating more directly with, methods and apparatus in accordance with the present disclosure. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art. Many alternatives and modifications will be apparent to those skilled in the art, once informed by the present disclosure.

Refer to FIG. 2 and FIG. 3. The first embodiment of the optical fingerprint sensor package of the present invention is introduced as follows. The optical fingerprint sensor package comprises a carrier 24, an image sensor 26, at least one LED (light emitting diode) 28, and a molding compound 30. For example, the carrier 24 is a substrate or a lead frame, and the LED 28 is an infrared (IR) LED, and the image sensor 26 is a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS). The carrier 24 is penetrated with a first cavity 32. The carrier 24 has a peripheral region 34 surrounding the first cavity 32. The peripheral region 34 is provided with first conductive pads 36 thereon. The image sensor 26 is mounted in the first cavity 32 and electrically connected to the first conductive pads 36 by conductive wire bonding. In the first embodiment, there is a plurality of LEDs (light emitting diodes) 28. The plurality of LEDs 28 is mounted to correspond to the peripheral region 34 of the carrier 24. In the first embodiment, each of the plurality of LEDs 28 is mounted on the peripheral region 34 of the carrier 24 through an adhesive 38 by surface-mount technology (SMT). For example, the adhesive 38 is a red glue or a silver paste. In order to prevent the side light of each LED 28 from interfering with the image sensor 26, the height of the bottom of each LED 28 is higher than the height of the top of the image sensor 26. The molding compound 30 covers the peripheral region 34 of the carrier 24, the image sensor 26, and each LED 28, and fills the first cavity 32 to fix the image sensor 26 in the first cavity 32 and expose the bottom of the image sensor 26 to an external space. The carrier 24 is not provided with any substrate thereunder. The thickness of the image sensor 26 is similar to that of the carrier 24. In addition, the thickness of the LED 28 is very thin. As a result, the present invention penetrates the carrier to form the cavity and places the image sensor in the cavity to decrease the thickness and volume of the optical fingerprint sensor package, such that the optical fingerprint sensor package is easily embedded in a thin panel or a thin glass cover.

Refer to FIG. 4 and FIG. 5. The second embodiment of the optical fingerprint sensor package of the present invention is introduced as follows. The optical fingerprint sensor package comprises a carrier 24, an image sensor 26, at least one LED (light emitting diode) 28, and a molding compound 30. For example, the carrier 24 is a substrate or a lead frame, and the LED 28 is an infrared (IR) LED, and the image sensor 26 is a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS). The carrier 24 is penetrated with a first cavity 32. The carrier 24 has a peripheral region 34 surrounding the first cavity 32. The peripheral region 34 is provided with first conductive pads 36 and second conductive pads 40 thereon and penetrated with at least one second cavity 42. The image sensor 26 is mounted in the first cavity 32 and electrically connected to the first conductive pads 36 by conductive wire bonding. In the second embodiment, there are a plurality of LEDs (light emitting diodes) 28 and a plurality of second cavities 42. The plurality of LEDs 28 is mounted to correspond to the peripheral region 34 of the carrier 24. In the second embodiment, the plurality of LEDs 28 is respectively mounted in the plurality of second cavities 42 of the peripheral region 34. In order to prevent the side light of each LED 28 from interfering with the image sensor 26, the height of the top of the carrier 24 is higher than the height of the top of each LED 28, such that the carrier 24 blocks the side light of each LED 28. The plurality of LEDs 28 is electrically connected to the second conductive pads 40 by conductive wire bonding. The molding compound 30 covers the peripheral region 34 of the carrier 24, the image sensor 26, and each LED 28, fills the first cavity 32 to fix the image sensor 26 in the first cavity 32 and expose the bottom of the image sensor 26 to an external space, and fills the plurality of second cavities 42 to fix the plurality of LEDs 28 in the plurality of second cavities 42 and expose the bottom of the plurality of LEDs 28 to the external space. The carrier 24 is not provided with any substrate thereunder. The thickness of the image sensor 26 is similar to that of the carrier 24. In addition, the thickness of the LED 28 is very thin. As a result, the present invention penetrates the carrier to form the cavity and places the image sensor in the cavity to decrease the thickness and volume of the optical fingerprint sensor package, such that the optical fingerprint sensor package is easily embedded in a thin panel or a thin glass cover.

In conclusion, the present invention penetrates the carrier to accommodate the image sensor, thereby reducing the thickness and volume of the optical fingerprint sensor package.

The embodiments described above are only to exemplify the present invention but not to limit the scope of the present invention. Therefore, any equivalent modification or variation according to the shapes, structures, features, or spirit disclosed by the present invention is to be also included within the scope of the present invention.

Claims

1. An optical fingerprint recognition sensor package comprising:

a carrier penetrated with a first cavity, the carrier having a peripheral region surrounding the first cavity, the peripheral region is provided with first conductive pads thereon;

an image sensor mounted in the first cavity and electrically connected to the first conductive pads by conductive wire bonding;

at least one LED (light emitting diode) mounted to correspond to the peripheral region of the carrier; and

a molding compound covering the peripheral region of the carrier, the image sensor, and the at least one LED, and filling the first cavity to fix the image sensor in the first cavity and expose a bottom of the image sensor to an external space.

2. The optical fingerprint sensor package according to claim 1, wherein the at least one LED is mounted on the peripheral region of the carrier through an adhesive by surface-mount technology (SMT).

3. The optical fingerprint sensor package according to claim 2, wherein the adhesive is a red glue or a silver paste.

4. The optical fingerprint sensor package according to claim 2, wherein a height of a bottom of the at least one LED is higher than a height of a top of the image sensor.

5. The optical fingerprint sensor package according to claim 1, wherein the peripheral region of the carrier is further provided with second conductive pads thereon and penetrated with at least one second cavity, the at least one LED is mounted in the at least one second cavity of the peripheral region, the molding compound fills the at least one second cavity to fix the at least one LED in the at least one second cavity and expose a bottom of the at least one LED to the external space, and the at least one LED is electrically connected to the second conductive pads by conductive wire bonding.

6. The optical fingerprint sensor package according to claim 5, wherein the at least one second cavity further comprises a plurality of second cavities, and the at least one LED further comprises a plurality of LEDs (light emitting diodes) respectively mounted in the plurality of second cavities.

7. The optical fingerprint sensor package according to claim 5, wherein a height of a top of the carrier is higher than a height of a top of the at least one LED.

8. The optical fingerprint sensor package according to claim 1, wherein the carrier is a substrate or a lead frame.

9. The optical fingerprint sensor package according to claim 1, wherein the at least one LED comprises a plurality of LEDs (light emitting diodes).

10. The optical fingerprint sensor package according to claim 1, wherein the at least one LED is an infrared (IR) LED.

11. The optical fingerprint sensor package according to claim 1, wherein the image sensor is a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS).