KR102199101B1 - Image sensor package for finger-print and electronic device capable of detecting finger-print - Google Patents

Abstract

The present invention relates to a fingerprint sensor. The fingerprint sensor package includes a parallel upper surface and a lower surface, and a first optical path extending at a first angle from an incidence area formed on one side of the lower surface to an effective fingerprint contact area formed on the upper surface, and the lower surface from the effective fingerprint contact area. A glass substrate providing a second optical path inclined at a second angle between the effective detection areas formed on the other side of the and an image disposed below the effective detection area, and generating a fingerprint image with light reaching the effective detection area Including a sensor, wherein the first angle is an angle between a straight line perpendicular to the lower surface and the first optical path, the second angle is an angle between a straight line perpendicular to the upper surface and the second optical path, the The first angle and the second angle are the same, and the incident area and the effective detection area do not overlap.

Description

TECHNICAL FIELD [Image sensor package for finger-print and electronic device capable of detecting finger-print}

The present invention relates to a fingerprint sensor.

The fingerprint sensor takes an image of a fingerprint and converts it into an electrical signal. For photographing a fingerprint image, a conventional optical fingerprint sensor includes an optical system that irradiates and reflects light on the fingerprint. However, since optical systems such as prisms, reflective mirrors, and lenses generally have a considerable volume, it is difficult to reduce the size of an electronic device including an optical fingerprint sensor.

Meanwhile, the types and numbers of electronic devices equipped with fingerprint sensors are increasing, centering on portable electronic devices such as mobile phones and tablets. In order to mount the fingerprint sensor on the front of the electronic device, the sensing part of the fingerprint sensor in contact with the fingerprint must be exposed to the outside. Therefore, if the entire front of the electronic device is covered with a protective medium such as a cover glass or a transparent film for design or display protection, a fingerprint sensor such as a capacitive method that detects changes in capacitance is placed on the front of the electronic device. Difficult to install

It is intended to provide an optical fingerprint sensor package that can be miniaturized and can generate a fingerprint image under a protective medium.

In an embodiment according to an aspect of the present invention, a fingerprint sensor package is provided. The fingerprint sensor package includes a parallel upper surface and a lower surface, and a first optical path extending at a first angle from an incidence area formed on one side of the lower surface to an effective fingerprint contact area formed on the upper surface, and the lower surface from the effective fingerprint contact area. A glass substrate providing a second optical path inclined at a second angle between the effective detection areas formed on the other side of the and an image disposed below the effective detection area, and generating a fingerprint image with light reaching the effective detection area Including a sensor, wherein the first angle is an angle between a straight line perpendicular to the lower surface and the first optical path, the second angle is an angle between a straight line perpendicular to the upper surface and the second optical path, the The first angle and the second angle are the same, and the incident area and the effective detection area do not overlap.

In an embodiment, a cover glass extending the first optical path and the second optical path may be in close contact with the upper surface of the glass substrate.

In an embodiment, the light traveling through the first optical path may be at least partially absorbed by the ridge of the fingerprint in the effective fingerprint contact area or reflected from the area where the ridge of the fingerprint does not contact.

In one embodiment, the image sensor is in close contact with the lower surface of the fingerprint sensor package so as to contact at least a part of the effective detection area.

In one embodiment, the image sensor may be spaced apart from the effective detection area.

In one embodiment, the image sensor may be in close contact with the lower surface of the glass substrate so that air is not interposed by using a material transparent to the wavelength band of the parallel plane light.

In an exemplary embodiment, a parallel surface light generator positioned below one side of the glass substrate may further include a parallel surface light generator that irradiates the parallel surface light traveling through the first optical path to the incident area.

In an embodiment, the parallel plane light generator may irradiate the parallel plane light such that an angle between a direction perpendicular to a lower surface of the glass substrate and a traveling direction of the parallel plane light is 85 to 90 degrees.

In an embodiment, the parallel plane light may be near infrared rays.

In one embodiment, the parallel plane light generator is periodically turned on and off, and the image sensor may generate both a fingerprint image when the parallel plane light generator is turned on and a fingerprint image when the parallel plane light generator is turned off.

The fingerprint sensor package according to an embodiment of the present invention can be miniaturized and can generate a fingerprint image under a protective medium.

In the following, the present invention is explained with reference to the embodiments shown in the accompanying drawings. For ease of understanding, throughout the accompanying drawings, like reference numerals are assigned to like elements. The configurations shown in the accompanying drawings are merely exemplary embodiments to describe the present invention, and are not intended to limit the scope of the present invention.
1 is a cross-sectional view illustrating a schematic structure and operation principle of a fingerprint sensor package.
FIG. 2 is an exemplary view showing in detail A and C of FIG. 1 in order to explain a change in a refraction angle according to an incident angle.
3 is a perspective view illustrating an example in which the fingerprint sensor package shown in FIG. 1 is located under a protection medium.
4 is an enlarged cross-sectional view of a lower portion of a fingerprint sensor package to illustrate an example of a parallel light generator.
5 is a cross-sectional view illustrating the role of the incidence angle adjuster shown in FIG. 4 by way of example.
6 is an enlarged cross-sectional view of a lower portion of one side of the fingerprint sensor package to exemplarily describe another example of the parallel plane light generator.
7 is a bottom view showing the bottom of the fingerprint sensor package to exemplarily describe the parallel surface light generator in FIG. 6.
8 is an enlarged cross-sectional view of a lower portion of one side of the fingerprint sensor package to exemplarily explain another example of the parallel plane light generator.
9 is a cross-sectional view illustrating an example in which one lower surface of a glass substrate is formed to be inclined.
10 is a perspective view illustrating an example in which a fingerprint sensor package is located under a protection medium.
11 and 12 are cross-sectional views taken along line II′ to exemplarily explain the operation of the fingerprint sensor package of FIG. 10.
13 is a cross-sectional view illustrating a structure and operation of a fingerprint sensor package as an example.
14 is a bottom view for explaining the structure of the fingerprint sensor package as an example.
15 is a top view exemplarily illustrating an operation of the fingerprint sensor package shown in FIG. 12.
16 is a cross-sectional view illustrating an exemplary structure of an image sensor.
17 is a cross-sectional view illustrating another structure of an image sensor as an example.

In the present invention, various modifications may be made and various embodiments may be provided. Specific embodiments are illustrated in the drawings and will be described in detail through detailed description. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Meanwhile, among terms used in the present specification, “substantially” and “nearly” are expressions for considering margins or possible errors applied in actual implementation. For example, “substantially 90 degrees” should be interpreted as including an angle at which the same effect as the effect of 90 degrees can be expected. As another example, “little” should be construed as including to the extent that something is negligible, even if it is insignificant.

1 is a cross-sectional view illustrating a schematic structure and operation principle of a fingerprint sensor package.

Referring to FIG. 1, a fingerprint sensor package includes an image sensor 100, a glass substrate 110, and a parallel plane light generator 120.

The parallel surface light generator 120 is located under one side of the glass substrate 110 and irradiates the parallel surface light 130 to the lower surface of the glass substrate 110 in the direction of the image sensor 100. The angle between the traveling direction of the parallel plane light 130 and the vertical direction of the lower surface of the glass substrate 110, that is, the incident angle of the parallel plane light 130 may be 85 degrees to 90 degrees. In other words, the parallel surface light generator 120 irradiates the parallel surface light 130 substantially parallel to the lower surface of the glass substrate 100. In an embodiment, the parallel plane light generator 120 may be a surface light emitting device in which the entire surface of the parallel plane light generator 120 facing the image sensor 100 emits light. For example, the parallel plane light generator 120 may be a laser diode or a light emitting diode (LED) capable of irradiating parallel plane light having high linearity. In addition, various structures of the parallel plane light generator 120 will be described in detail with reference to FIGS. 4 to 8.

In an embodiment, the parallel plane light generator 120 may generate near-infrared (NIR) parallel plane light of 850 nm to 950 nm. Compared to short wavelength light, near-infrared rays have a better light absorption rate in the skin, so a clear fingerprint image can be obtained. Therefore, in the case of using the near-infrared parallel surface light, a fingerprint image is obtained by turning the parallel surface light generator 120 on or off at a certain frequency, and the difference between the fingerprint image obtained at turn-on and the fingerprint image obtained at turn-off is calculated. Can be used for recognition. Meanwhile, when an electronic device equipped with a fingerprint sensor package is used outdoors, near-infrared rays included in natural light may diffuse into a finger. In this case, contrary to the fingerprint image obtained by the parallel plane light, the ridges of the fingerprint may appear relatively bright and the valleys may appear dark. Accordingly, a clear fingerprint image among the fingerprint images acquired when the parallel surface light generator 120 is turned on and the fingerprint images acquired when the parallel light generator 120 is turned off may be used for fingerprint recognition.

In another embodiment, the parallel plane light generator 120 may generate parallel plane light of a short wavelength. Here, the parallel plane light may be UVA (Ultraviolet A) having a wavelength of 320 nm to 400 nm or blue light having a wavelength of 450 nm or less. When an electronic device equipped with a fingerprint sensor package is used outdoors, pixels of the image sensor 100 are saturated by external light, so that a fingerprint image cannot be generated. In order to prevent this phenomenon, short wavelength parallel plane light may be used.

The glass substrate 110 provides an optical path through which the parallel plane light 130 enters the image sensor 100. The parallel plane light 130 is refracted from the lower surface of the glass substrate 110 to become the refracted parallel plane light 140 and 150 (hereinafter referred to as refracted light), and the refracted light 140 and 150 is on the upper surface of the glass substrate 110. It becomes the primary reflected and reflected parallel plane light 145 and 155 (hereinafter, reflected light). The reflected light 145 and 155 is incident on the image sensor 100 and is used to generate a fingerprint image. The width W_LE of the effective parallel plane light incident area on the lower surface of the glass substrate 110 may be determined by the incident angle of the parallel plane light 130. The width W_C of the effective fingerprint contact area on the upper surface of the glass substrate 110 is determined by the thickness T _GS of the glass substrate 110, and accordingly, the width of the fingerprint image may be determined. The effective fingerprint contact area is an area in which the reflected light 145 and 155 that is absorbed or reflected by the fingerprint and incident on the image sensor 100 among areas in which the refracted light 140 and 150 are primarily reflected is emitted. Accordingly, the width W_C of the effective fingerprint contact area may be less than or equal to the width W_IS of the image sensor 100. The width W_C of the effective fingerprint contact area that changes according to the thickness T _GS of the glass substrate 110 will be described in detail with reference to FIG. 3.

The width W_GS of the glass substrate 110 is larger than the width W_IS of the image sensor 100. As shown in FIG. 1, the glass substrate 110 provides a light path through which the parallel plane light 130 incident through the lower surface is primarily reflected on the upper surface and is incident on the image sensor 100. The parallel plane light 130 incident on the lower surface of the glass substrate 110 is refracted by the angle of refraction determined by the angle of incidence and is directed toward the upper surface of the glass substrate 110. The refracted lights 140 and 150 are first reflected from the top surface of the glass substrate 110 at a reflection angle equal to the refractive angle, and are incident on the image sensor 100. For this reason, the effective fingerprint contact area on the upper surface of the glass substrate 110 is formed between the image sensor 100 and the parallel surface light generator 120. When viewed from the top of the fingerprint sensor package, the effective fingerprint contact area and the image sensor 100 may at least partially overlap according to the thickness T _GS of the glass substrate 110.

The image sensor 100 is located on the lower surface of the other side of the glass substrate 110, and the upper surface of the image sensor 100 is in close contact with the lower surface of the glass substrate 110. The lower surface of the glass substrate 110 and the upper surface of the image sensor 100 are substantially flat, and may be in close contact so that air is not interposed by using a material transparent to the wavelength band used, for example, clear epoxy. When air is interposed between the image sensor 100 and the lower surface of the glass substrate 110, the reflected light 145 and 155 is the lower surface of the glass substrate 110 or the image sensor 100 due to the difference in refractive index between the glass substrate and the air layer. The surface reflectivity on the upper surface is increased, and as a result, the reflected light 145 and 155 is refracted in a direction parallel to the air layer. At this time, the angle of refraction may be the same as the initial angle of incidence. As a result, the reflected light 145 and 155 does not enter the image sensor 100. In addition, if the image sensor 100 is not in close contact with the lower surface of the glass substrate 110, light from the outside may be incident on the image sensor 100 at various angles of incidence through the air layer.

The image sensor 100 generates a fingerprint image 160. In the fingerprint image 160, the ridges of the fingerprint are relatively dark and the valleys of the fingerprint appear relatively bright. In the effective fingerprint contact area, the portion A where the ridges of the fingerprint contact, absorb or scatter the refracted light 140. Accordingly, the reflected light 145 emitted from the portion A in contact with the ridge of the fingerprint disappears or has a relatively small amount of light. For this reason, the image sensor 100 hardly detects the reflected light 145 reflected by the ridge. Conversely, in the effective fingerprint contact area, the portion B where the valley of the fingerprint contacts does not absorb or scatter the refracted light 150. Accordingly, the reflected light 155 emitted from the portion B in contact with the valley of the fingerprint has an amount of light that is hardly lost. Accordingly, the image sensor 100 may detect the reflected light 155 reflected by the valley. Accordingly, in the fingerprint image 160, the valley B'of the fingerprint appears relatively brighter than the ridge A'of the fingerprint.

FIG. 2 is an exemplary view showing in detail A and C of FIG. 1 in order to explain a change in a refraction angle according to an incident angle.

In FIGS. 2A to 2C, the incident angles of the parallel plane lights 210a, 210b, and 210c are defined as θ1 and the refraction angle is defined as θ2, respectively. Here, the incident angle θ1 is the angle between the traveling direction of the parallel plane light 210a, 210b, and 210c and the direction perpendicular to the lower surface of the glass substrate 200, and the refraction angle θ2 is the traveling direction of the refracted light 220a, 220b, 220c and glass It is an angle between the vertical direction of the lower surface of the substrate 200.

The parallel plane lights 210a, 210b, and 210c are irradiated from the parallel plane light generator and are incident on the glass substrate 200 at the incident point C. In FIG. 2, it is illustrated that the parallel plane lights 210a, 210b, and 210c are incident on the glass substrate 200 having, for example, a refractive index N2 = 1.5 through air having a refractive index N1 = 1.0. The incident angle θ1 and the refractive angle θ2 at the incident point C have the same relationship as N1 X Sin θ1 = N2 X Sin θ2. Table 1 below can be obtained by calculating the angle of refraction θ2 by increasing the angle of incidence θ1 from 0° to 5° using this relationship.

Referring to Table 1, when the incidence angle θ1 is 0 degrees, the parallel plane lights 210a, 210b, and 210c do not refract and enter the glass substrate 200, and the refraction angle θ2 continuously increases as the incidence angle θ1 increases. In the section in which the incident angle θ1 changes by 5 degrees from 0 to 35 degrees, the refraction angle θ2 increases by approximately 3 degrees, and in the section where the incidence angle θ1 changes by 5 degrees from 35 degrees to 60 degrees, the refraction angle θ2 increases by approximately 2 degrees, and the incident angle θ1 In this section that changes by 5 degrees from 60 degrees to 80 degrees, the refraction angle θ2 increases by approximately 1 degree, and in the section where the incidence angle θ1 changes by 5 degrees from 80 degrees to 90 degrees, the refraction angle θ2 increases by approximately 0.4 degrees. Meanwhile, the distance x between the incident point C according to the incident angle θ1 and the thickness T _GS of the glass substrate 200 and the point where the reflected light 230a, 230b, and 230c meet the lower surface of the glass substrate 200 is the incident angle θ1 at 0 degrees. Between 55 degrees, it increases by substantially the same increment Δx, and as the incidence angle θ1 becomes greater than 55 degrees, the increment Δx begins to decrease, and when the incidence angle θ1 is greater than 85 degrees, the increment Δx becomes very small compared to the previous section of 85 degrees. In sum, if the incident angle θ1 falls in the section from 85° to 90°, even if the incident angle θ1 changes, it becomes the same as parallel light with little change in distance x, and uniform refracted light 220a, 220b, 220c and uniform reflected light ( 230a, 230b, 230c) may be generated.

On the other hand, when the thickness of the glass substrate is increased from 1 mm to 2 mm, the optical path in the glass substrate 200 of the refracted light 220a, 220b, 220c and uniform reflected light 230a, 230b, 230c increases, and the As a result, the distance x increases substantially in proportion to the increase in the height of the organic substrate 200. An increase in the distance x indicates an increase in the effective fingerprint contact area formed on the upper surface of the glass substrate 200. A relationship in which an effective fingerprint contact area capable of detecting a fingerprint increases as the optical path increases will be described below with reference to FIG. 3.

3 is a perspective view illustrating an example in which the fingerprint sensor package shown in FIG. 1 is located under a protection medium.

The protective medium is an optically transparent medium and prevents damage to the outer surface of the electronic device. An example of such a protective medium is a cover glass that is attached to the front surface of a mobile phone to protect the display. Meanwhile, in FIG. 3, one protective medium having a thickness T _CG is illustrated, but two or more protective mediums may be overlapped. For example, a protective film may be attached to the upper surface of the cover glass. For the sake of simplicity, the protective medium is shown to have the same shape and width as the fingerprint sensor package, but the protective medium may be extended in the lateral direction.

3, the upper surface of the glass substrate 310 of the fingerprint sensor package is in close contact with the lower surface of the cover glass, which is a protective medium, so that air is not interposed. When the upper surface of the glass substrate 310 is in close contact with the lower surface of the cover glass, the refracted light is not reflected from the contact surface between the upper surface of the glass substrate 310 and air, but is reflected after reaching the upper surface of the cover glass. When air is interposed between the cover glass and the glass substrate 310, the surface reflectance at the upper surface of the glass substrate 310 or the lower surface of the cover glass increases due to the difference in refractive index between the glass substrate and the air layer. The reflected light is refracted in a direction parallel to the air layer and thus does not enter the glass substrate 310. Therefore, between the upper surface of the glass substrate 310 and the lower surface of the cover glass must be in close contact so that no air is introduced.

The width W_C' of the effective fingerprint contact area and the width W_VD' of the effective detection area of the fingerprint sensor package may be increased by a protection medium. Here, it is assumed that the parallel plane light generator 320 irradiates parallel plane light to the same parallel plane light incident area regardless of the presence or absence of the protective medium.

In the absence of the cover glass, the glass substrate 310 of the thickness T _GS has an effective parallel plane light incident area of width W_LE' and an effective fingerprint contact area of width W_C'. The parallel plane light incident on the lower surface of the glass substrate 310 before reaching the effective parallel plane light incidence area is also reflected from the upper surface of the glass substrate 310, but does not reach the effective detection region of the image sensor 300, so it is not used for fingerprint image generation. can not do it. Due to the thickness T _GS of the glass substrate 310, the width W_VD' of the effective detection area of the image sensor 300 is smaller than the width W_IS of the image sensor, so that the generated fingerprint image contains the area 360 where the fingerprint is expressed and the fingerprint. It has an unrepresented area 365. Since the image sensor 300 is in close contact with the lower surface of the glass substrate 310, the parallel plane light cannot go straight any more by the image sensor 300, and thus, the image sensor 300 is located on the glass substrate 310. I cannot enter the company. As a result, an area 365 in which a fingerprint is not expressed is generated.

When there is a cover glass, the optical path of the refracted and reflected light increases by the thickness T _CG of the cover glass. That is, the cover glass serves to increase the thickness of the glass substrate 310 from T _GS to T _total . The glass substrate 310 having a thickness of T _total has an effective parallel plane light incident area of width W_LE and an effective fingerprint contact area of width W_C. Since the width W_VD of the effective detection area of the image sensor 300 is substantially the same as the width W_IS of the image sensor by the thickness T _total of the glass substrate 310, the generated fingerprint image has only the area 370 in which the fingerprint is expressed. do. That is, due to the increase in thickness due to the cover glass, the reflected light reaching the image sensor 300 increases, so that the area where the fingerprint is not expressed disappears.

The effective fingerprint contact area formed on the upper surface of the cover glass functions the same as the effective fingerprint contact area formed on the upper surface of the glass substrate 310. That is, the refracted light is reflected or absorbed by the valleys and ridges of the fingerprint so that the reflected light can be used to generate a fingerprint image. For this reason, the fingerprint sensor package can generate a fingerprint image even under a protective medium such as a cover glass. Meanwhile, it is preferable that the refractive index of the cover glass is substantially the same as the refractive index of the glass substrate 310. However, since the cover glass and the glass substrate 310 are in close contact, the width W_C of the effective fingerprint contact area does not change significantly even if the refractive light and the reflected light are refracted to some extent between the glass substrate-cover glass and cover glass-glass substrate.

In order for the image sensor to generate a clear fingerprint image, short wavelength parallel surface light may be used. Compared to light such as visible light or near-infrared light, short-wavelength parallel plane light has a lower effect of passing through fingers or spreading from the skin. Therefore, if the parallel plane light of a short wavelength is used, it may be very effective when external light other than the parallel plane light incident from the parallel plane light generator 310 is blocked. Shading of external light can be implemented in various ways. For example, the glass substrate 310 may function as a band pass filter that passes only short wavelength light. In another embodiment, in FIG. 3, a short-wavelength band-pass film 330 through which only short-wavelength light passes is shown attached to the entire lower surface of the glass substrate 310, but the image sensor 300 among the lower surfaces of the glass substrate 310 The short-wavelength band-pass film may be interposed only in the area where is in close contact, or the short-wavelength band-pass film may be attached to the whole or part of the upper surface of the glass substrate 310.

4 is an enlarged cross-sectional view of a lower portion of one side of the fingerprint sensor package to illustrate an example of the parallel plane light generator, and FIG. 5 is a cross-sectional view illustrating the role of the incidence angle adjuster illustrated in FIG. 4 by way of example.

Referring to FIG. 4, the parallel plane light generator includes a light source 420 and a guide 421. The light source 420 may be an LED that irradiates omni-directional light. The omnidirectional light is guided to parallel plane light by a guide 421 located at an output end of the light source 420. The guide 421 allows at least a portion of the omni-directional light to be irradiated to the lower surface of the glass substrate 410 at an incident angle of 85 degrees to 90 degrees. The parallel plane light incident by the guide 421 becomes the refracted light 440 inside the glass substrate 410. In one embodiment, the guide 421 may be formed of a material that blocks or absorbs omni-directional light directed toward the inner surface of the guide.

On the other hand, although passing through the optical path defined by the guide 421, light 450 and 460 having an incident angle greater than 90 degrees may be generated. In order to prevent the light (450, 460) having an incidence angle greater than 90 degrees from being incident on the glass substrate 410 to generate unwanted refracted light or to be incident on the image sensor 400, the incident angle controller 430 It may be located between the sensor 400 and the parallel plane light generator. The light 450 having the first incident angle is reflected by the incident angle adjuster 430 to have a first incident angle smaller than 90 degrees, and is incident on the lower surface of the glass substrate 410. At this time, since the first incident angle is refracted at an angle of 85 degrees or less, most of the refracted light is transmitted to the outside through the top surface of the glass substrate 410 and disappears, or close to the light source 420 at an angle significantly different from the refracted light 440. As it enters the lower surface of the glass substrate 410, the light reflected from the upper surface of the glass substrate 410 does not reach the image sensor 400 and is refracted back to the lower surface of the glass substrate 410. The light 460 having a second incident angle (greater than the first incident angle) is reflected by the incident angle adjuster 430 to have a second positive incident angle, and cannot enter the lower surface of the glass substrate 410.

In addition to changing the path of light with a large incident angle, the incident angle adjuster 430 may increase parallel plane light incident on the glass substrate 410. Here, the incident angle of the parallel plane light that can be adjusted so that the incident angle controller 430 is incident on the glass substrate 410 may vary depending on the angle between the incident angle controller 430 and the glass substrate 410.

As shown in (a) of FIG. 5, when the incident angle controller 430 is positioned between the parallel plane light generator 420 and the image sensor 400 so that the incidence angle controller 430 is horizontal to the glass substrate 410, the parallel plane light having an incidence angle of 90 degrees to 95 degrees ( A parallel surface light 471 having an incidence angle of 85 degrees to 90 degrees that 470 is mostly reflected from the upper surface of the incidence angle adjuster 430 and is incident on the glass substrate 410. In addition, the parallel plane light that is first refracted from the upper surface of the incidence angle adjuster 430 into the interior of the incidence angle adjuster 430 is mostly reflected from the lower surface of the incidence angle adjuster 430 and is then secondly refracted from the upper surface of the incidence angle adjuster 430. The secondary refracted light becomes parallel plane light 472 having an incident angle of 85 degrees to 90 degrees. On the other hand, some of the primary refracted parallel plane light comes out from the lower surface of the incident angle adjuster 430 to the outside 473, but does not enter the glass substrate 410. As a result, parallel surface light incident on the glass substrate 410 increases, and a clearer fingerprint image can be generated.

The largest ratio of the radial optical paths from the light source 420 such as LED is substantially straight light having an incident angle of 90 degrees. When the incident angle controller 430 is positioned between the parallel plane light generator 420 and the image sensor 400 so as to be inclined by a certain angle, for example, 5 degrees with respect to the glass substrate 410, as shown in FIG. As a result, the parallel plane light 480 having an incidence angle of 90 degrees is mostly reflected from the upper surface of the incidence angle adjuster 430 and becomes a parallel plane light 481 having an incidence angle of 85 degrees to 90 degrees that can be incident on the glass substrate 410. That is, when the top surface of the incidence angle adjuster 430 is inclined so as to be lowered in the left direction based on (b) of FIG. 5, the top surface of the incidence angle adjuster 430 faces the parallel plane light generator 420 located on the left. On the other hand, as in the case (a) of FIG. 5, the parallel plane light that is primarily refracted from the upper surface of the incidence angle adjuster 430 into the interior of the incidence angle adjuster 430 is mostly reflected from the lower surface of the incidence angle adjuster 430, and then the incident angle adjuster ( It is secondarily refracted on the upper surface of 430). The secondary refracted light becomes a parallel plane light 482 having an incident angle of 85 degrees to 90 degrees. On the other hand, some of the primary refracted parallel plane light comes out from the lower surface of the incident angle adjuster 430 (483), but is not incident on the glass substrate 410. Due to this, the parallel surface light incident on the glass substrate 410 increases, and a clearer fingerprint image can be generated.

6 is an enlarged cross-sectional view of a lower portion of one side of the fingerprint sensor package to exemplarily describe another example of the parallel surface light generator, and FIG. 7 is a bottom surface of the fingerprint sensor package to exemplarily describe the parallel surface light generator in FIG. 6. It is a bottom view shown.

6 and 7, the parallel plane light generator includes a reflector 520 and a light source 525. The light source 525 may be a point light source LED that irradiates omni-directional light toward the reflector 520. The reflector 520 irradiates the parallel surface light 530 on the lower surface of the glass substrate 510 in the direction of the image sensor 500. The cross section of the reflecting mirror 520 that reflects the omnidirectional light is a parabolic mirror, and the curvature of the reflector 520 is that the non-directional light irradiated by the light source 525 is reflected by the reflector 520 and has an incident angle of 85 degrees to 90 degrees. Can be determined to have. That is, the curvature of the cross section of the reflector 520 determines the incident angle of the parallel plane light 530.

The reflector 520 extends by the length of the image sensor 500 in the longitudinal direction to guide the non-directional light irradiated by the light source 525 to the parallel plane light 530. Referring to FIG. 7, the reflector 520 extends by the length of the image sensor 500, and may be a mirror having a parabolic shape curved in a left direction based on FIG. 7. Here, the longitudinal direction is a vertical direction based on FIG. 7. The longitudinal curvature of the reflector 520 may be determined so that the reflected parallel light 530 travels horizontally toward the image sensor 500. By making the reflector 520 a parabolic surface (FIG. 7) not only in the cross section (FIG. 6) but also in the length direction, it is possible to generate the parallel surface light 530 having good linearity using a point light source.

8 is an enlarged cross-sectional view of a lower portion of one side of the fingerprint sensor package to exemplarily explain another example of the parallel plane light generator.

Referring to FIG. 8, the parallel plane light generator includes a light source 620 and a reflector 623. In one embodiment, the light source may be a laser diode or an LED that irradiates straight light 630 having high straightness. In another embodiment, the light source 620 may be an LED that irradiates omni-directional light. In this case, the non-directional light is guided to the straight light 630 by guides 621 and 622 located at the output end of the light source 620. The light source 620 may be disposed at a position close to the image sensor 600. Due to this configuration, since the optical path from the light source 620 to the lower surface of the glass substrate 610 increases, parallel surface light having high straightness may be incident on the glass substrate 610.

The reflector 623 irradiates parallel light on the lower surface of the glass substrate 610 in the direction of the image sensor 600. The reflector 623 is a parabolic mirror, and the curvature of the reflector 623 may be determined such that the straight light 630 is reflected by the reflector 623 to have an incidence angle of 85 degrees to 90 degrees.

9 is a cross-sectional view illustrating an example in which the lower surface of one side of the glass substrate is formed to be inclined.

9, the lower surface of the glass substrate 710 is a parallel surface PS to which the image sensor 700 is in close contact, and an inclined surface SS formed to be inclined so that the thickness of the glass substrate 710 becomes thin in the direction of one side of the glass substrate 710. Include. The inclined surface SS is formed to be inclined to the parallel surface PS by an inclination angle θ3. In Fig. 7, the parallel plane light generator irradiates parallel plane light incident on the inclined plane SS at 85 degrees to 90 degrees. Here, it goes without saying that the parallel plane light generator may have the configuration described in FIGS. 5 and 6.

The sloped surface SS may reduce the thickness of the glass substrate 710. A glass substrate with a thickness T _SGS that is smaller than the thickness T _GS of the glass substrate shown in FIG. 1 can provide the same effective fingerprint contact area. Since the inclined surface SS has an inclination angle θ3 with respect to the parallel surface PS, the refraction angle θ2' of the parallel surface light incident on the inclined surface SS becomes a value obtained by adding the inclination angle θ3 to the refraction angle θ2 shown in FIG. 2. That is, when the refraction angle θ2' increases, the optical path of the refracted light and the reflected light in the glass substrate 700 becomes longer, so that the distance x'between the points where the refracted light and the reflected light contact the lower surface of the glass substrate 700 increases. do. Accordingly, even if the thickness T _SGS of the glass substrate 700 is decreased, it is possible to obtain an effective fingerprint contact area and an effective detection area substantially the same as or wider than that generated in the structure shown in FIG. 1.

The glass substrate 700 having an inclined surface illustrated in FIG. 9 may be applied to the configurations illustrated in FIGS. 10 to 14 as well as the configurations illustrated in FIGS. 1 to 3.

10 is a perspective view illustrating an example in which a fingerprint sensor package is located under a protection medium.

Referring to FIG. 10, the fingerprint sensor package includes an image sensor 800, a glass substrate 810, and first and second parallel light generators 820 and 825, and the upper surface of the glass substrate 810 of the fingerprint sensor package Silver may be in close contact with the lower surface of the cover glass, which is a protective medium.

The first and second parallel plane light generators 820 and 825 are respectively located under one side and the other side of the glass substrate 810, and irradiate the parallel plane light onto the lower surface of the glass substrate 810 in the direction of the image sensor 800 . The incident angle of each parallel plane light irradiated by the first and second parallel plane light generators 820 and 825 is 85 degrees to 90 degrees, but as shown in FIG. 10, the first parallel plane light generator 820 has parallel plane light from left to right. And the second parallel plane light generator 825 irradiates parallel plane light from right to left. For example, the first and second parallel plane light generators 120 may be laser diodes or light emitting diodes (LEDs) capable of irradiating parallel plane light having high linearity. In addition, the parallel plane light generator of various structures described above in FIGS. 6 to 8 may be applied. In addition, as shown in FIG. 9, the lower surface of the glass substrate 810 may include a plurality of inclined surfaces formed in a direction from the center to which the image sensor 800 is in close contact toward the left and right side surfaces.

In an embodiment, the first and second parallel plane light generators 820 and 825 may generate near-infrared parallel plane light. In another embodiment, the first and second parallel plane light generators 820 and 825 may generate short-wavelength parallel plane light.

The glass substrate 810 and the cover glass provide an optical path through which incident parallel light is incident on the image sensor 800. The parallel plane light enters the lower surface of the glass substrate 810 and is primarily reflected from the upper surface of the cover glass. Since the first and second parallel surface light generators 820 and 825 are located opposite to each other on one and the other lower surfaces of the glass substrate 810, respectively, the first effective fingerprint contact area 840 and the second effective fingerprint are provided on the upper surface of the cover glass. A contact area 845 is formed. If the thickness T _total is smaller if, the may be the first effective fingerprint contact region 840 and the second fingerprint image between valid fingerprint contact area 845 is not acquired region is formed, increasing the thickness T _total, the first effective As the widths of the fingerprint contact area 840 and the second effective fingerprint contact area 845 increase, an area in which a fingerprint image is not obtained may decrease. The reflected light from the first effective fingerprint contact area 840 and the second effective fingerprint contact area 845 is incident on the image sensor 800 and is used to generate a fingerprint image.

The image sensor 800 is located at the center of the lower surface of the glass substrate 810, and the upper surface of the image sensor 800 is in close contact with the lower surface of the glass substrate 810. The lower surface of the glass substrate 810 and the upper surface of the image sensor 800 are substantially flat.

11 and 12 are cross-sectional views taken along line II′ to exemplarily explain the operation of the fingerprint sensor package of FIG. 10.

The first and second parallel plane light generators 920 and 925 are alternately turned on to irradiate the parallel plane light onto the lower surface of the glass substrate 910. Referring to FIG. 11, the first parallel plane light generator 920 located under one side of the glass substrate 910 is turned on to transfer the first parallel plane light 921 between the first parallel plane light generator 920 and the image sensor 900. The lower surface of the glass substrate 910 is irradiated. At this time, the second parallel plane light generator 925 is turned off. The refracted light refracted from the lower surface of the glass substrate 910 is reflected from the left area of the fingerprint non-acquisition area of the width W_ND among the fingerprint contact areas of width W_C''. When the reflected light enters the image sensor 900, a fingerprint image is generated. At this time, the reflected light enters only the remaining detection area 901 of the image sensor 900 except for the fingerprint non-acquisition area of width W_ND. Accordingly, the fingerprint image generated by the image sensor 900 has an area 940 in which a fingerprint in contact with the left area of the fingerprint contact area is expressed and an area 945 in which the fingerprint is not expressed. The width of the area 945 in which the fingerprint is not expressed is the same as the width W_ND of the non-fingerprint area.

Referring to FIG. 12, the second parallel plane light generator 925 located under the other side of the glass substrate 910 is turned on to transfer the second parallel plane light 926 between the image sensor 900 and the second parallel plane light generator 925. The lower surface of the glass substrate 910 is irradiated. At this time, the first parallel plane light generator 920 is turned off. The refracted light refracted from the lower surface of the glass substrate 910 is reflected in the right area of the fingerprint non-acquisition area of width W_ND among the fingerprint contact areas of width W_C''. The reflected light is incident on the image sensor 900 to generate a fingerprint image. At this time, the reflected light is incident on the image sensor 900 only to the remaining detection area 902 except for the fingerprint non-acquisition area of width W_ND. Accordingly, the fingerprint image generated by the image sensor 900 has an area 950 in which a fingerprint in contact with the right area of the fingerprint contact area is expressed and an area 955 in which no fingerprint is expressed. The width of the area 955 in which the fingerprint is not expressed is the same as the width W_ND of the fingerprint non-acquisition area. Since the image sensor 900 is in close contact with the lower surface of the glass substrate 910, the parallel plane lights 921 and 926 cannot go straight any more by the image sensor 900, and thus the image sensor image sensor 900 It cannot enter into the lower surface of the located glass substrate 910. As a result, areas 945 and 955 in which a fingerprint is not expressed are generated.

In an embodiment, the fingerprint images generated through the process described in FIGS. 11 and 12 may be used for fingerprint recognition, respectively, or may be synthesized based on areas 945 and 955 in which a fingerprint is not expressed and used for fingerprint recognition. .

13 is a cross-sectional view illustrating a structure and operation of a fingerprint sensor package as an example.

13, the fingerprint sensor package includes an image sensor 1100, a glass substrate 1110, and first and second parallel light generators 1120 and 1125, and the upper surface of the glass substrate 1110 of the fingerprint sensor package. Silver adheres to the lower surface of the cover glass, which is a protective medium. Compared with the fingerprint sensor package shown in FIG. 10, in the fingerprint sensor package shown in FIG. 13, the first and second parallel plane light generators 1120 and 1125 are simultaneously turned on to generate a fingerprint image. To this end, the fingerprint sensor package illustrated in FIG. 13 includes an image sensor or a pair of image sensors having a width larger than that of the image sensor 800 illustrated in FIG. 10.

When the width of the image sensor 1100 is increased, the first and second parallel plane light generators 1120 and 1125 are simultaneously turned on to generate a fingerprint image. As shown in FIG. 11, the first and second parallel plane light generators 1120 and 1125 located under both sides of the glass substrate 1110 simultaneously transmit the first and second parallel plane lights 1121 and 1126 to the glass substrate 1110. ) On the underside of it. The first and second refracted lights refracted from the lower surface of the glass substrate 1110 are reflected in the left and right areas of the fingerprint non-acquisition area of width W_ND among the fingerprint contact areas of width W_C''. The first reflected light reflected from the left area of the fingerprint non-acquisition area W_ND is incident on the left detection area of the image sensor 1100, and the second reflected light reflected from the right area of the fingerprint non-acquired area W_ND is the right side of the image sensor 1100. It is incident on the detection area and a fingerprint image is generated. Therefore, the fingerprint image generated by the image sensor 1100 is an area 1140 in which a fingerprint in contact with the left area of the fingerprint contact area is expressed, an area 1141 in which a fingerprint in contact with the right area of the fingerprint contact area is expressed, and a fingerprint It has this unrepresented area 1142. Even if there is an area 1142 in which the fingerprint is not expressed, fingerprint recognition may be performed by acquiring a plurality of fingerprint images while moving the fingerprint location of the finger and synthesizing them.

14 is a bottom view for explaining the structure of the fingerprint sensor package by way of example. 15 is a top view exemplarily illustrating an operation of the fingerprint sensor package shown in FIG. 14.

Referring to FIG. 14, the upper surface of the image sensor 1200 is in close contact with the center of the lower surface of the glass substrate 1210, and the first to fourth parallel surface light generators 1220, 1221, 1222, and 1223 are formed of the glass substrate 1210. It is located on each side. As shown in FIG. 9, the lower surface of the glass substrate 1210 may include a plurality of inclined surfaces formed in a direction from a central portion to which the image sensor 1200 is in close contact toward each side.

The first to fourth parallel plane light generators 1220, 1221, 1222, and 1223 are located under each side of the glass substrate 1210, and the parallel plane light is irradiated on the lower surface of the glass substrate 1310 in the direction of the image sensor 1200 do. The incident angle of each parallel plane light irradiated by the first to fourth parallel plane light generators 1220, 1221, 1222, and 1223 is 85 degrees to 90 degrees, but the first parallel plane light generator 1220 is the first parallel plane light from the left side to the right side. The second parallel plane light generator 1221 irradiates the second parallel plane light from the right side to the left, and the third parallel plane light generator 1222 irradiates the third parallel plane light from the upper side to the downward direction. 4 The parallel plane light generator 1223 irradiates the fourth parallel plane light from the lower side to the upward direction. The traveling direction of the first parallel plane light or the second parallel plane light and the traveling direction of the third parallel plane light or the fourth parallel plane light may be perpendicular to each other.

The glass substrate 1210 has a square plate shape, and provides a light path through which incident parallel light is incident on the image sensor 1200.

Referring to FIG. 15, the first to fourth parallel plane light generators 1220, 1221, 1222, and 1223 are alternately turned on to irradiate the parallel plane light onto the lower surface of the glass substrate 1310. FIG. 15A shows the effective fingerprint contact area 1320 formed on the upper surface of the glass substrate 1310 when the first parallel plane light generator 1220 is turned on, and FIG. 15B shows the second parallel plane light. The effective fingerprint contact area 1321 formed on the upper surface of the glass substrate 1310 when the generator 1221 is turned on is shown, and FIG. 15C shows a glass substrate (c) when the third parallel plane light generator 1222 is turned on. The effective fingerprint contact area 1322 formed on the upper surface of 1310 is shown, and FIG. 15D shows the effective fingerprint contact area formed on the upper surface of the glass substrate 1310 when the fourth parallel surface light generator 1223 is turned on. Shows (1323). The fingerprint images generated through the process described in FIGS. 15A to 15D may be processed and used for fingerprint recognition, or synthesized and used for fingerprint recognition.

Meanwhile, two of the first to fourth parallel plane light generators 1220, 1221, 1222, and 1223 that face each other may be turned on at the same time to irradiate the parallel plane light onto the lower surface of the glass substrate 1310. FIG. 15(e) shows the effective fingerprint contact area 1324 formed on the upper surface of the glass substrate 1310 when the first and second parallel plane light generators 1220 and 1221 are turned on, and FIG. 15(f) Denotes an effective fingerprint contact area 1325 formed on the upper surface of the glass substrate 1310 when the third and fourth parallel plane light generators 1222 and 1223 are turned on.

16 is a cross-sectional view illustrating a structure of an image sensor as an example, and FIG. 17 is a cross-sectional view illustrating another structure of an image sensor.

When external light is incident on the fingerprint sensor package, the pixels of the image sensor are saturated and a fingerprint image cannot be generated. In particular, when an electronic device equipped with a fingerprint sensor package is located outdoors, a situation in which the fingerprint sensor package does not operate normally may occur. In order to prevent such a situation, a short-wavelength band-pass film that uses short-wavelength parallel surface light and passes only short-wavelength light may be attached to the lower surface or upper surface of the glass substrate. The structures shown in FIGS. 16 and 17 show a structure of an image sensor capable of minimizing the influence of external light on the generation of a fingerprint image.

16 shows a shield layer for blocking light implemented in a back-illuminated structure (BIS) image sensor. The image sensor is formed under the semiconductor substrate 1520, the light-receiving element 1530 formed on the upper surface of the semiconductor substrate, and the light-receiving element 1530 in the semiconductor substrate, and is an electrical wiring between the light-receiving element 1530 and an external connection terminal (not shown). A plurality of metal layers 1540 forming a, a protective layer 1500 formed on the light receiving element 1530, and a shield layer 1510 formed on the light receiving element 1530 in the protective layer 1500 . Here, a photodiode is shown as an example of the light-receiving element 1530, but it is not necessarily limited thereto, and various types of light-receiving elements may be used.

The shield layer 1510 blocks external light that is substantially vertically incident toward the light receiving element 1530. The shield layer 1510 may be formed of, for example, metal. To this end, a plurality of shield layers 1510 are formed vertically above each of the plurality of light receiving elements 1530, and the plurality of shield layers 1510 are spaced apart by a predetermined distance. An area of the shield layer 1510 defined by a horizontal length and a vertical length is equal to or larger than the area of the light-receiving element 1530 to block light incident vertically above the light-receiving element 1530. On the other hand, the light path through which the light 1550 incident from the upper left side toward each light receiving element 1530 passes and/or the light incident at a certain angle toward each light receiving element 1530 from the upper right side (1555) The optical path passing through may be defined by a separation distance between the plurality of shield layers 1510 and a height between the shield layer 1510 and the light receiving element 1530.

At least a portion of an area around the light path of the upper surface of the protective layer 1500 may be color coated. In one embodiment, the upper surface of the protective layer 1500 positioned vertically above the shield layer 1510 may be coated with, for example, a white or black material. If the area in which the image sensor is located is different from the surrounding color, it can cause visually different feelings. In the image sensor, since a light path through which reflected light is incident is formed from the upper surface of the protective layer 1500 to the light receiving element 1530, the upper surface of the protective layer 1500 is preferably coated with a darker color than the surrounding color.

17 shows a light blocking structure implemented in a front-illuminated structure (FIS) image sensor. The image sensor is formed in the semiconductor substrate 1620, the light-receiving element 1630 formed on the upper surface of the semiconductor substrate, the protective layer 1600 formed on the upper surface of the light-receiving element 1630, and the light-receiving element 1630 and It includes a metal layer 1610 forming an electric wire between external connection terminals (not shown) and forming an optical path inclined at a predetermined angle.

The metal layer 1610 including M1 and M2 metal lines blocks external light that is substantially vertically incident toward the light receiving element 1530. To this end, when viewed from the top of the image sensor, an M2 metal line is formed over an area where the M1 metal line is not formed so that the light-receiving element 1630 is covered by the M1 metal line and the M2 metal line. On the other hand, although the M1 metal line is formed vertically above the light receiving element 1630 and the metal layer 1610 is shown as being formed of two metal lines, this is only an example, and the M2 metal line is the light receiving element 1630 ) Can be formed vertically above. In addition, the metal layer 1610 may include three or more metal lines. For example, when the metal layer 1610 is formed of M1 to M4 metal lines, the distance between the M3-M4 metal lines is M1-M2 metal. By forming the distance between the lines or the distance between the M2-M3 metal lines, external light that is substantially vertically incident toward the light receiving element 1630 may be blocked. Meanwhile, at least a portion of an area around the light path of the upper surface of the protective layer 1600 may be color coated. In one embodiment, the upper surface of the protective layer 1600 positioned vertically above the uppermost metal layer may be coated with, for example, a white or black material.

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects.

The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

Claims (10)

It includes parallel upper and lower surfaces,
A first optical path extending at a first angle from an incident area formed on one side of the lower surface to an effective fingerprint contact area formed on the upper surface, and
A glass substrate providing a second optical path inclined at a second angle between the effective fingerprint contact area and the effective detection area formed on the other side of the lower surface;
It is located under one side of the glass substrate and irradiates the incident area with the parallel light traveling through the first optical path through the air, but the angle between the direction perpendicular to the lower surface of the glass substrate and the traveling direction of the parallel light is 85 A parallel plane light generator configured to irradiate the parallel plane light to be from degrees to 90 degrees so that the first angle is a total reflection angle with respect to the effective fingerprint contact area; And
An image sensor disposed below the effective detection area and generating a fingerprint image with light reaching the effective detection area,
The first angle is an angle between a straight line perpendicular to the lower surface and the first optical path, the second angle is an angle between a straight line perpendicular to the upper surface and the second optical path, the first angle and the The second angle is the same,
The fingerprint sensor package in which the incident area and the effective detection area do not overlap. The fingerprint sensor package of claim 1, wherein a cover glass extending the first and second optical paths is in close contact with an upper surface of the glass substrate. The method according to claim 2, wherein the light traveling through the first optical path,
At least part of the ridge of the fingerprint is absorbed in the effective fingerprint contact area, or
A fingerprint sensor package that is reflected from an area where the ridges of the fingerprint are not in contact. The fingerprint sensor package of claim 1, wherein the image sensor is in close contact with the lower surface so as to contact at least a part of the effective detection area. The fingerprint sensor package of claim 1, wherein the image sensor is spaced apart from the effective detection area. The fingerprint sensor package of claim 5, wherein the image sensor is in close contact with the lower surface of the glass substrate so that air is not interposed by using a material transparent to the wavelength band of the parallel plane light. delete delete The fingerprint sensor package according to claim 1, wherein the parallel plane light is near infrared rays. The method of claim 1, wherein the parallel plane light generator is periodically turned on and off,
The image sensor is a fingerprint sensor package that generates both a fingerprint image when the parallel surface light generator is turned on and a fingerprint image when the parallel surface light generator is turned off.

Images