KR20190028939A - Display capable of detecting finger-print - Google Patents

Abstract

The present invention relates to a display. According to an aspect of the present invention, an embodiment provides a display having a fingerprint recognition function. The display having a fingerprint recognition function comprises: a display panel where light having various incident angles representing ridges and valleys of a finger touching a cover glass passes, wherein the display panel is disposed at a lower part of the cover glass; and an image sensor layer detecting a detection target light which has a detection target incident angle from the light having various incident angles to generate a fingerprint image, wherein the image sensor layer is disposed at a lower part of the display panel. When the finger touches the cover glass, the ridge may be a point light source which irradiates light diffused through a skin of the finger toward the image sensor layer.

Description

[0001] The present invention relates to a display capable of detecting a fingerprint,

The present invention relates to a display.

The fingerprint sensor captures an image of the fingerprint and converts it into an electric signal. In order to capture a fingerprint image, a conventional optical fingerprint sensor has an optical system for irradiating a fingerprint to reflect light. However, since an optical system such as a prism, a reflection mirror, and a lens generally has a considerable volume, an electronic device equipped with an optical fingerprint sensor is difficult to miniaturize.

On the other hand, the number and types of electronic devices equipped with fingerprint sensors are increasing, especially in portable electronic devices such as mobile phones and tablets. In order to mount the fingerprint sensor on the front surface of the electronic device, the sensing portion of the fingerprint sensor contacting the fingerprint must be exposed to the outside. Therefore, when the entire front surface of the electronic device is covered with a protective medium such as a cover glass or a transparent film in order to protect the design or the display panel, a fingerprint sensor such as a capacitive sensing method It is difficult to mount on the front. In addition, it is difficult to place the fingerprint sensor under the display panel.

And a display capable of generating a fingerprint image in an area where the image is displayed.

A display capable of generating a fingerprint image by using the display panel as a light source in an environment in which the ambient light is very low and generating a fingerprint image using only ambient light in other environments is provided. Here, the ambient light or the panel light is diffused through the skin of the finger.

The ridge of the fingerprint on the finger skin contacts the cover glass, but the fingerprint does not contact the cover glass. Since the difference in the refractive index between the skin and the cover glass is relatively smaller than the difference in the refractive index between the air and the cover glass, the range of the incident angle of the light incident directly into the cover glass from the ridge of the fingerprint, Is different from the incident angle range of light incident on the light source. A fingerprint image can be generated using only light that can not come out of the fingerprint using the principle that the angle of light incident to the inside of the cover glass is limited due to the difference in refractive index.

An embodiment according to one aspect of the present invention provides a display having a fingerprint recognition function. A display having a fingerprint recognition function includes a display panel disposed at a lower portion of a cover glass and through which light having various incident angles representing ridges and valleys of fingers touching the cover glass passes, And an image sensor layer for detecting a detection target light having an incident angle of incidence of the light having various incidence angles to generate a fingerprint image, wherein when the finger contacts the cover glass, the ridge passes through the skin of the finger And may be a point light source that irradiates the diffused light toward the image sensor layer.

In one embodiment, light diffused through the skin of the finger may be generated by ambient light.

In one embodiment, light diffused through the skin of the finger may be generated by the panel light illuminated by the display panel.

In one embodiment, the image sensor layer may include a light selection structure for selecting the detection subject light from light having the various incident angles, and a light selection structure located below the light selection structure, For example.

In one embodiment, the light selection structure may include a prism sheet for refracting light having the detection subject incident angle from the light having the various incident angles at a first angle, and a prism sheet positioned below the prism sheet, And refracted light at a second angle.

In one embodiment, the optical path extending layer interposed between the microlens and the image sensor may be further included.

In one embodiment, the image sensor may include a light receiving unit that is disposed below the microlens and generates a pixel current corresponding to the light refracted at the second angle, wherein the light receiving unit is disposed on a lower side Lt; / RTI >

In one embodiment, the prism sheet includes a plurality of first inclined surfaces and a plurality of second inclined surfaces alternately arranged to form prism mountains and prism valleys, wherein the first inclined surface is a portion of the light having the various incident angles, The light having the incident angle of incidence may be refracted at a first angle, and the inclination angle of the first inclined plane may be smaller than the inclination angle of the second inclined plane.

In one embodiment, the light selection structure may include a plurality of first inclined surfaces and a plurality of second inclined surfaces alternately arranged to form prism valleys, wherein light among the lights having the various incident angles, And a microlens which is located at a lower portion of the prism sheet and refracts light refracted at a first angle to a second angle, wherein an upper end of the first inclined surface is a second inclined surface And a lower end of the first inclined surface and a lower end of the second inclined surface may be connected to both ends of a lower surface extending in parallel.

In one embodiment, the optical path extending layer interposed between the microlens and the image sensor may be further included.

In one embodiment, the light selection structure may include a prism sheet for refracting light having the detection subject incident angle from the light having the various incident angles at a first angle, and a prism sheet positioned below the prism sheet, And a second micro lens for refracting the light refracted at the second angle to a third angle, the first micro lens being disposed on an upper surface of the image sensor, .

In one embodiment, the image sensor is formed of a thin film transistor, and the image sensor layer may be formed on at least a part or an entire area of a lower surface of the display panel.

A display according to an embodiment of the present invention can generate a fingerprint image in an area where an image is displayed.

Hereinafter, the present invention will be described with reference to the embodiments shown in the accompanying drawings. For the sake of clarity, throughout the accompanying drawings, like elements have been assigned the same reference numerals. It is to be understood that the present invention is not limited to the embodiments illustrated in the accompanying drawings, but may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof. In particular, the accompanying drawings, in order to facilitate an understanding of the invention, are intended to illustrate some of the elements in some exaggeration. It is to be understood that the breadth, thickness, etc. of the components illustrated in the figures may vary with actual implementations, since the drawings are a means for understanding the invention.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exemplary view schematically showing a display of an electronic device incorporating a display having a fingerprint recognition function. FIG.
2 is a view schematically showing a concept of generating a diffusion type fingerprint image using panel light or ambient light.
3 is a diagram illustrating a process of fingerprint recognition in an electronic device.
FIG. 4 is a view illustrating an exemplary display panel that operates as a light source.
5 is a view for explaining an embodiment for generating a diffusion type fingerprint image.
6 is a diagram for explaining another embodiment for generating a diffusion type fingerprint image.
Fig. 7 is a functional diagram of a sensor driver for executing the method of generating the diffusion type fingerprint image shown in Fig. 5 or Fig.
8 is an exemplary diagram schematically showing the principle of generating a fingerprint image in a spreading manner
FIG. 9 is a cross-sectional view illustrating a display having a fingerprint recognition function according to I-I 'of FIG. 1, illustrating a diffusion method.
10 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to an embodiment.
11 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment.
12 is a cross-sectional view exemplarily showing a structure for selecting an incident angle by the second microlens.
13 is a cross-sectional view illustrating a manner in which light other than the incident angle of incidence is blocked in the image sensor layer of FIG.
14 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment.
15 is a cross-sectional view exemplarily showing a section of an image sensor layer according to another embodiment.
16 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment.
17 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment.
18 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment.
FIG. 19 is a sectional view exemplarily showing a cross section of a display having a fingerprint recognition function according to another embodiment.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. In particular, the functions, features, and embodiments described below with reference to the accompanying drawings, may be implemented alone or in combination with other embodiments. It is, therefore, to be understood that the scope of the present invention is not limited only to the forms shown in the accompanying drawings.

The terms " substantially ", " substantially ", " approximately ", and the like are used in the present specification to express a margin to be applied in actual implementation or a possible error. For example, " substantially 90 degrees " should be interpreted to mean an angle that can be expected to have the same effect as the effect at 90 degrees. As another example, "little" should be interpreted to mean something negligible even if something is negligible.

On the other hand, unless otherwise specified, " side " or " horizontal " refers to the left and right direction of the drawing, and " vertical " refers to the up and down direction of the drawing. Unless otherwise defined, angles, incident angles, etc. are based on a hypothetical straight line perpendicular to the horizontal plane shown in the drawing.

Throughout the accompanying drawings, the same or similar elements are referred to using the same reference numerals.

1 is an exemplary view schematically showing an electronic device to which a display having a fingerprint recognition function is coupled.

The display includes a display panel 300, a touch sensor (not shown) and an image sensor layer 100 or a fingerprint sensor package (not shown). The image sensor layer 100 or the fingerprint sensor package captures a fingerprint of the finger 50 located in the upper cover glass 200 to generate a fingerprint image. The image sensor layer 100 may be formed or attached to at least a portion or all of the underside of the display panel 300 to produce a fingerprint image at any location. The fingerprint sensor package is disposed on the lower surface of the display panel 300, and can generate a fingerprint image at a placement position. Since the image sensor layer 100 and the fingerprint sensor package have the same principle and structure as those of the display panel 300 except that the area occupied by the lower surface of the display panel 300 and / 100) will be mainly described.

Fig. 1 shows a smart phone in which a cover glass 200 is attached to an entire surface of an electronic device 10, for example. On the lower surface of the cover glass 200, upper and lower coating areas 11a and 11b defining an area for exposing the display panel 300 are formed. Depending on the type of the electronic device 10, left and right coating areas (not shown) may be connected to both ends of the upper and lower coating areas 11a and 11b, respectively. A display panel 300 occupying a relatively large area and a speaker, a camera, and / or an illuminance sensor 12 occupying a relatively small area may be disposed on the front surface of the electronic device 10. [ The illuminance sensor 12 can sense the ambient brightness of the space in which the electronic device 10 is located. The cover glass 200 covers the entire display panel 300 and may cover part or all of the front surface of the electronic device 10 depending on the type of the electronic device 10. [ The display panel 300 is positioned below the cover glass 200 and the image sensor layer 100 is positioned below the display panel 300.

The display may generate a fingerprint image using light generated by the display panel 300 (hereinafter referred to as panel light) and / or ambient light. Here, the ambient light may be direct light other than the panel light, for example, direct sunlight or reflected light by the sun, or direct light or reflected light irradiated from artificial light. The ambient light may include light having a wavelength of red or more, for example, a wavelength in the red to near-IR band, which may be diffused in the finger skin as in the panel light. An embodiment of generating a fingerprint image using panel light and / or ambient light is described in detail below with reference to FIGS. 2 to 9, and an embodiment of the image sensor layer 100 is described below with reference to FIGS. 10 to 19 Will be described in detail.

2 is a view schematically showing a concept of generating a diffusion type fingerprint image using panel light or ambient light.

Referring to FIG. 2, the diffusion method generates a fingerprint image using the phenomenon that the panel light 20 or the ambient light 21 generated by the display panel 300 is diffused through the skin. The light diffused into the skin can be irradiated into the cover glass 200 from the contact point of the cover glass-ridge when the ridge of the fingerprint contacts the cover glass 200. Here, the contact point of the cover glass-ridge acts as an infinite point light source. On the other hand, the light irradiated from the fingerprint is incident into the cover glass 200 through the air-cover glass 200 interface, so that the light is refracted at a limited angle. Therefore, there is a range not overlapping between the incident angle of the light irradiated by ridges and the incident angle of the light refracted by the valleys, and the detection object incident angle can be selected from the incident angles within the range not overlapping. Since the light irradiated from the ridges of the fingerprint is detected, the ridges of the fingerprints appear relatively bright in the diffusion type fingerprint image, and the fingerprints appear relatively dark. The principle of generating the diffusion type fingerprint image will be described in detail below with reference to FIGS. 8 and 9. FIG.

In one embodiment, the light source that generates the panel light 20 necessary to generate the fingerprint image may be the display panel 300. The display panel 300 can turn on the combination of R, G, and B pixels to generate the panel light 20 that is irradiated toward the finger. Here, the panel light 20 is, for example, a visible light, and may be white light or red light. 2 illustrates a panel light 20 that is incident substantially vertically toward the finger 50. This is for the sake of brevity and does not limit the direction of the panel light 20 to a vertical direction . When the finger 50 is located in the fingerprint acquisition area 30 on the display panel 300 of the electronic device 10, a combination of R, G, and B pixels located at the bottom of the fingerprint acquisition area 30 and / The combination of R, G, and B pixels located under the region other than the region 30 can be turned on.

In another embodiment, in an environment where the amount of light necessary for generating a fingerprint image from the ambient light 21 is sufficiently provided, for example, outdoors, the display can generate a fingerprint image with only the ambient light 21. 2 illustrates the ambient light 21 that is incident substantially vertically toward the finger 50. This is for the sake of brevity and does not limit the direction of the ambient light 21 to the vertical direction . The display driver for driving the display panel 300 and / or the application processor of the electronic device 10 receive the measured values representing the ambient brightness from the ambient light sensor 12 and use the display panel 300 as a light source Can be determined. For example, the application processor of the display driver and / or electronic device 10 may generate a combination of R, G, and B pixels located at the bottom of the fingerprint acquisition region 30, if the fingerprint image can be generated with only the ambient light 21 Or the combination of R, G, and B pixels located below the region other than the fingerprint acquisition region 30 may not be turned on.

FIG. 3 is a diagram illustrating a process of fingerprint recognition in an electronic device, and FIG. 4 is a diagram illustrating a display panel that operates as a light source.

Referring to FIG. 3, the electronic device 10 may be, for example, a smartphone. Fingerprint recognition can be used to recognize or authenticate a user. (a), in order to turn on the smartphone, when the user presses the power button or touches the display, the fingerprint acquisition area 30 where the finger 50 is to be positioned is displayed on the display. The fingerprint acquisition area 30 may be any location (for the image sensor layer 100) or a predetermined location (for the fingerprint sensor package). For example, the fingerprint acquisition area 30 may be displayed at substantially the same position as the home button. Although the fingerprint acquisition area 30 is shown as a rectangle in this specification including (a), this is merely an example, and the fingerprint acquisition area 30 may be displayed in various shapes, for example, a circle, an oval, Lt; / RTI > Further, the fingerprint acquisition area 30 may be displayed with any pattern (e.g., fingerprint), color, or a combination thereof.

(b) shows a state where the user places the finger 50 in the fingerprint acquisition area 30, (c) shows a state in which the light source area 31 of the display panel 300 at the time of generating the fingerprint image is turned on . As described above with reference to Figures 1 and 2, the diffuse fingerprint image may be generated using either panel light 20, ambient light 21, or a combination thereof. Therefore, the light source region 31 for irradiating the panel light 20 is not necessarily turned on.

The combination of R, G, and B pixels located in the light source region 31 is turned on to irradiate the panel light 20 toward the finger 50. 4 (a) to 4 (d), the light source regions 31, 32, and 33 may be located on any one of a lower surface, a left surface, and a right surface of the fingerprint acquisition area 30 or a combination thereof. The light source regions 31, 32, and 33 are disposed at positions where at least a portion is covered by the finger 50. The light source areas 31 and 32 are formed in consideration of the characteristics of the display panel 300 such as resolution, maximum brightness, environment such as the brightness of the ambient light 21, and / or sensor characteristics such as the resolution of the image sensor layer / , 33) can be determined. In one embodiment, the light source area 31 may not overlap with the fingerprint acquisition area 30. In another embodiment, at least a portion of the light source region 31 may overlap the fingerprint acquisition region 30. [

On the other hand, when the fingerprint image is generated, pixels located in the remaining area of the display panel 300 except the light source areas 31, 32, and 33 may be turned off. Light generated on the opposite side of the light source region 31 on the basis of the fingerprint acquisition region 30 may affect the quality of the fingerprint image. Fingerprint recognition is completed within tens to hundreds of microseconds, and the time required to generate fingerprint images is only a fraction of the time. Thus, the temporary turn-off of the display panel 300 may not be recognized by the user.

(d) shows a state in which the fingerprint recognition is completed. If fingerprint recognition is used for user authentication of the smartphone, the smartphone may be unlocked.

5 is a view for explaining an embodiment for generating a diffusion type fingerprint image.

In step 600, the display panel 300 displays the fingerprint detection area 30.

In step 610, the image sensor 500 evaluates the quality of the fingerprint image generated by the current setting 641. [ The image sensor 500 may use the lookup table 640 to change the sensor settings. The lookup table 640 includes values of parameters determined according to image generation conditions such as, for example, indoor, outdoor, and the like. For example, the exposure time Exp, the gain G, and the like are parameters of the image sensor 500 that affect the generation and quality of the image at a limited light amount condition. The current setting 641 may be a previously selected sensor setting or a default sensor setting.

When evaluating whether the current setting is appropriate, the light source region 31 may be turned on or off. For example, in order to evaluate whether ambient light 21 is sufficient to generate a fingerprint image, the light source area 31 may be turned off. As another example, the light source region 31 may be turned on to evaluate whether both the panel light 20 and the ambient light 21 are sufficient to generate a fingerprint image.

The criterion for evaluating the quality of the fingerprint image can be variously set. The quality evaluation of the fingerprint image can be performed using a histogram. A fingerprint image expressed in gray scale is used to find patterns and feature points of a fingerprint on the basis of relatively bright or relatively dark pixels. Therefore, the higher the contrast ratio of the fingerprint image, the better the fingerprint recognition. When the fingerprint recognition is performed indoors, the contrast ratio of the fingerprint image generated by the current setting 641 may be low. Therefore, the setting of the image sensor 500 can be changed. Similarly, when fingerprint recognition is performed outdoors, the light receiving portion of the image sensor 500 can be saturated. Therefore, the setting of the image sensor 500 can be changed. On the other hand, if the contrast ratio of the fingerprint image is more than the predetermined reference, the fingerprint image generation (step 630) may be omitted and the fingerprint image may be output (step 640) by changing the sensor settings (step 620)

If it is necessary to change the sensor setting according to the evaluation result of step 610, the sensor setting is changed to the new sensor setting 642 in step 620, and a fingerprint image is generated in step 630 with the new sensor setting 642. [ Upon generation of the fingerprint image with the new sensor configuration 642, the light source region 31 may be turned on to generate the panel light 20. On the other hand, if the fingerprint image can be generated only by the ambient light 21, the light source region 31 can be turned off.

In step 640, the image sensor 500 outputs the generated fingerprint image. The output fingerprint image can be used for fingerprint recognition by the application processor.

The operation of the above-described display panel and image sensor 500 can be performed without mutual communication according to a predetermined operation sequence. On the other hand, the above-described operations of the display panel and the image sensor 500 can be executed by mutual communication or by control of an application processor.

6 is a diagram for explaining another embodiment for generating a diffusion type fingerprint image.

In step 700, the display panel 300 displays the fingerprint detection area 30.

In step 710, the sensor settings to be applied to fingerprint image generation are determined. The sensor setting can be determined by one or more conditions. In this case, the case where the illuminance sensor 12 uses the measurement value generated by measuring the brightness of the ambient light 20 is exemplified. The lookup table 740 includes values of one or more parameters assigned to each of the plurality of measured values. The look-up table 740 of FIG. 6 illustrates the case where the value of the parameter linearly increases or decreases according to the measured value, but this is an example for the sake of understanding.

Here, steps 700 and 710 may be executed at the same time, or step 710 may be executed before step 700. For example, the image sensor 500 may periodically or upon occurrence of an event receive measurements from the ambient light sensor 12 to determine the sensor settings. Here, the event includes a situation where the fingerprint recognition may be required, such as the touch sensor sensing the user's touch, the user pressing the power button, or the execution of an application requiring fingerprint recognition.

In step 720, when a sensor setting is determined and applied to the image sensor 500, a fingerprint image is generated. In generating a fingerprint image, the light source region 31 may be turned on to generate the panel light 20. On the other hand, if the fingerprint image can be generated only by the ambient light 21, the light source region 31 can be turned off.

In step 730, the image sensor 500 outputs the generated fingerprint image. The output fingerprint image can be used for fingerprint recognition by the application processor.

The operation of the above-described display panel and image sensor 500 can be performed without mutual communication according to a predetermined operation sequence. On the other hand, the above-described operations of the display panel and the image sensor 500 can be executed by mutual communication or by control of an application processor.

Fig. 7 is a functional diagram of a sensor driver for executing the method of generating the diffusion type fingerprint image shown in Fig. 5 or Fig.

The electronic device 10 includes an application processor 13 (hereinafter referred to as an AP), a display driver 14, and a sensor driver 15. The electronic device 10 may include various other components in addition to the components described above. However, the other components are not necessarily related to the present invention, and those skilled in the art can readily predict and understand the operation of the present invention, so that the description thereof will be omitted.

The AP 13 executes one or more programs required for the operation of the electronic device 10 and controls the operation of components such as the display driver 14 and the sensor driver 15. [ For example, the AP 13 may drive the display driver 14, the sensor driver 15, or the like to generate a diffusion type fingerprint image, and perform the fingerprint recognition using the generated fingerprint image. In addition, the AP 13 may evaluate the quality of the generated fingerprint image.

The AP 13 may perform at least a portion of the steps described in FIG. 5 or FIG.

When a program in execution requests fingerprint recognition, the AP 13 controls the display panel 300 to display the fingerprint acquisition area 30 to be touched by a finger or acquire positional information of a finger-contacted area from the touch sensor can do. The AP 13 can drive the display panel 300 to turn on the light source area 31 so that the sensor driver 15 can generate the fingerprint image.

The display driver 14 drives the display panel 300 to display the fingerprint acquisition area 30 and controls turning on and off of the light source area 31. [

The sensor driver 15 drives the image sensor 500 to generate a diffusion type fingerprint image. The sensor driver 15 may include a column decoder 151, a readout circuit 152, an image signal processor 153 and a memory 154.

The image sensor 500 is composed of a plurality of unit pixels. The unit pixel converts the light incident on the ridge or ridge of the fingerprint located on the upper side into the pixel current.

The column decoder 151 drives the image sensor 500 in units of columns. The unit pixels arranged in the column selected by the column decoder 151 output the pixel current through the data line.

The readout circuit 152 receives the pixel current from the unit pixels arranged in the column selected by the column decoder 151 through the data line. The lead-out circuit 152 may be variously implemented, and generally includes a comparator, a correlated double sampling (CDS), an analog-digital converter (ADC), and the like. The lead-out circuit 152 can output a digital code corresponding to the pixel current.

The image signal processor 153 generates a fingerprint image using the digital code output from the lead-out circuit 152. In addition, the image signal processor 153 changes the sensor settings using a look-up table stored in the memory 154. In addition, the image signal processor 153 may evaluate the quality of the fingerprint image.

FIG. 8 is an enlarged view of a part of the fingerprint acquisition area 30 of FIG. 1, schematically illustrating a principle of generating a fingerprint image by a diffusion method.

Referring to FIG. 8A, only the light having an incident angle to be detected in the light incident on the image sensor layer 100 due to the ridge of the fingerprint is reflected by the image sensor layer 100, And has a structure in which light having an angle other than the angle of incidence to be detected does not reach the light-receiving unit. That is, when light is incident on the skin, the light acts as an infinite point light source in the skin of the finger 50. When the finger is placed on the cover glass 200, the ridge of the fingerprint, for example, a portion of the fingerprint that does not contact the cover glass 200, for example, And irradiates the inside of the cover glass 200 with light having different incident angle ranges. In detail, the light irradiated from the fingerprint of the finger passes through the air interposed between the skin and the cover glass 200, and then enters into the cover glass 200. Therefore, due to the difference in refractive index between the air and the cover glass 200, the incident angle range of the light irradiated from the fingerprints is relatively larger than the incident angle range of the light directly irradiated to the inside of the cover glass 200 from the ridge of the fingerprint narrow. The light emitted from the ridge of the fingerprint and the light irradiated from the bone have the same incident angle range except for the light and the incident angle that can be irradiated only from the ridge of the fingerprint, Can be generated. Hereinafter, this principle will be described in detail with reference to (b) to (d).

Referring to FIG. 8 (b), the fingerprint is composed of ridges and valleys, and the ridges contact the upper surface of the cover glass 200, but the ridges do not contact the upper surface of the cover glass 200. The protective medium is a visually transparent medium through which light can pass and prevents the outer surface of the electronic device 10 from being damaged. One example of such a protective medium is a cover glass 200 attached to the front surface of the mobile phone to protect the display panel 300. Hereinafter, the cover glass 200 will be described as an example of a protective medium.

The ridges and ridges of the fingerprint function as multiple light sources for irradiating light from the upper surface of the cover glass 200 toward the light receiving portion of the image sensor layer 100. A point A where the ridgeline contacts the upper surface of the cover glass 200 acts as a light source to irradiate light in all directions and irradiate light from the upper surface of the cover glass 200 into the inside of the cover glass 200. On the other hand, since the light irradiated from the non-contacting surface of the cover glass 200 reaches the point B on the upper surface of the cover glass 200 through the air between the valley and the cover glass 200, do. Therefore, the cover glass incident angle? _R of the light incident on the inside of the cover glass 200 at the point A may fall within a range of about 0 degree to about 180 degrees, The incident angle of the cover glass of the light &thetas; _v can fall within a relatively narrow range as compared with the cover glass incident angle &thetas; _r due to the difference between the air refractive index and the cover glass refractive index. Here, the angle of incidence of the cover glass on the left side of the cover glass 200 substantially horizontally is 0 degrees, the angle of incidence of the cover glass incident on the cover glass 200 substantially perpendicular to the upper surface of the cover glass 200 is 90 degrees, It is assumed that the angle of incidence of the cover glass on the right side of the glass 200 substantially horizontally is 180 degrees. Hereinafter, the angle of light incident into the cover glass 200 is referred to as a cover glass incidence angle.

The image sensor layer 100 is formed on the lower surface of the display panel 300. Unlike an LCD in which an additional structure for generating light such as a backlight and a reflector is required on the lower surface of the display panel 300, an AMOLED display does not require an additional structure because a unit pixel directly generates light. On the other hand, the electrodes and / or the wirings occupying a large portion of the unit pixel area of the display panel 300 may be formed of a material that blocks light such as a metal, but may be formed of an optically transparent medium for electrical insulation, IMD, or the like. Thereby, a region through which light can pass exists between the electrode and / or the wiring. Accordingly, the display panel 300 interposed between the cover glass 200 and the image sensor layer 100 can provide an extended light path through which light incident from the cover glass 200 can pass. In other words, substantially the same result as forming the image sensor layer 100 on the lower surface of the cover glass which is thicker than the normal cover glass can be expected. As will be described in detail below, the image sensor layer 100 has a structure capable of selecting an incident angle of light to be detected. Therefore, even if a light incident by the interposed display panel 300 is refracted to some extent, at least one condition for selecting the angle of incidence of light is adjusted so that light having an incident angle of incidence at the lower portion of the display panel 300 Can be detected.

The image sensor layer 100 passes through the cover glass 200 and the display panel 300 to select light having a predetermined detection object incident angle? ₁ among the light incident on the upper surface of the image sensor layer 100. 8C shows light having an incident angle θ _{r '} to be selected by the light selection structure of the image sensor layer 100 among lights incident on the upper surface of the image sensor layer 100, Represents light having the detection object incident angle? ₁ finally reaching the light receiving portion of the image sensor 500 among the light having the incident angle? _{R '} . That is, the light selecting structure of the image sensor layer 100 selects light having an incident angle of incidence with the light having a predetermined incident angle directed to the lower portion of the image sensor layer 100 where the light receiving unit is located. Here, light having the detection subject incident angle? ₁ is referred to as detection target light.

8 (c), the optical selection structure of the image sensor layer 100 blocks light incident on the left side of the points A and B among the light incident into the image sensor layer 100, and additionally, , And blocks light having the same incident angle as that of the light incident on the right side of the point B among the light incident on the right side of the point A. Through this, light with an incident angle [theta] _{r '} can be selected. For example, when the cover glass incident angle? _R falls within a range of about 0 degree to about 180 degrees and the cover glass incident angle? _V falls within a range of about 42 degrees to about 132 degrees, the incident angle? _{R '} 140 degrees, but this is merely an example, and it goes without saying that it may vary depending on the characteristics of the optical selective structure.

8 (d), light having a detection object incident angle? ₁ to be incident on the light receiving portion of the light selected by the light selection structure can be selected. For example, the angle of incidence θ _{r 'If} in the range 132 degrees to 140 degrees, the detection subject incident angle θ ₁ is, but may be in the range 135 degrees to 140 degrees, which is merely an example, the position of the micro-lens, aperture, the size And the like, depending on the characteristics of the optical selection structure. Here, the light having the detection object incident angle? ₁ is refracted while passing through the optical selection structure, and the angle? R when the light is finally incident on the light receiving portion may be different from the detection object incident angle? ₁ . 8 (c) and 8 (d) illustrate a structure for generating a fingerprint image by blocking light incident on the left side of the point A, but also a structure for blocking light incident to the right side of the point A Substantially the same fingerprint image can be generated.

Since the light having the incident angle of incidence? ₁ is an angle that only the light generated by the ridge of the fingerprint can have, a fingerprint image having a relatively high contrast ratio can be generated. When the fingerprint is placed on the cover glass 200 as shown in FIG. 8 (b), not only the light due to the ridge but also the light due to the goal also enters the inside of the cover glass. Since the conventional optical fingerprint sensor has a structure for detecting light incident vertically, it is possible to detect not only light incident substantially vertically from the ridge toward the upper surface of the light receiving portion but also light substantially perpendicular to the upper surface of the light receiving portion from the ridge . Thus, a fingerprint image having a relatively low contrast ratio, in which the boundary between the ridge and the valley of the fingerprint is not clear, is generated. On the other hand, the display having the fingerprint recognition function according to the present invention has a structure for detecting at least a part of light generated by ridges in the light generated by the contact surface of the fingerprint, A relatively high fingerprint image can be generated.

FIG. 9 is a cross-sectional view illustrating a display having a fingerprint recognition function according to I-I 'of FIG. 1, illustrating a diffusion method.

Referring to FIG. 9, the electronic device has a structure in which a protective medium, a touch sensor, a polarizing film, a display panel 300, and an image sensor layer 100 are laminated. The cover glass 200 may use visible light such as white light or red light so that the light irradiated from the ridge of the fingerprint can be effectively incident into the display panel.

The lights 321 to 328 incident on the inside of the cover glass 200 by ridges located on the upper surface of the cover glass 200 reach the first point 320 on the display panel 300. The incident angle &thetas; _i1 of the lights 321 to 328 is an angle with a straight line perpendicular to the upper surface of the cover glass 200. [ The lights 321 to 328 are incident at different points on the upper surface of the cover glass 200 and reach the first point 320 on the display panel 300 through different light paths. Of the lights 321 to 328 incident on the image sensor layer 100 at the first point 320, the lights 325 to 328 incident from the right side of the first point 320 toward the first point 320 And is blocked by the optically selective structure 400. Light 321, 322, and 324 having an incident angle? _I1 other than the detection object incident angle? ₁ among lights 321 to 324 incident from the left side of the first point 320 toward the first point 320, It is blocked by the selective structure 400 or has a light path different from the light to be detected. That is, the detection target light is refracted to reach the light receiving portion of the image sensor 500 by the optical selection structure 400 enters the final light-receiving unit as the angle of incidence θ _2, but the detected angle of incidence light having an incidence angle θ _i1 other than θ ₁ (321, 322, 324) are finally refracted at the incident angle [theta] ₃ or [theta] ₄ and are not incident on the light receiving part or blocked by the light selecting structure 400. [

The point at which the detection target light 323 is incident on the cover glass 200 and the light receiving unit for detecting the point are not located on the same vertical line. The optical selection structure 400 blocks light having a common incident angle from the light incident on the ridge and the ridge of the fingerprint and allows only a part of the light due to the ridge to reach the image sensor 500. Therefore, the detection target light passes through the cover glass 200 and the display panel 300 with an inclined optical path. Thus, the point where the detection target light 323 is incident on the upper surface of the cover glass 200 and the point where the detection light 323 is incident on the image sensor layer 100 are positioned on different vertical lines. The horizontal distance between the point where the detection target light 323 is incident on the upper surface of the cover glass 200 and the point where the detection target light 323 is incident on the image sensor layer 100 is a sum of the thickness of the cover glass 200 and the thickness of the display panel 300 Can be determined by the total thickness T _total and the incident angle? ₁ of the light 323 to be detected. That is, if the total thickness T _total increases or the incident angle of incidence? ₁ increases, the horizontal distance may increase.

10 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to an embodiment.

10 (a) and (b), the image sensor layer 100 includes a light selection structure 400 and an image sensor 500. The optical selection structure 400 is positioned below the display panel 300 and the optical selection structure 400 includes a prism sheet 410 and a first microlens 430. The prism sheet 410 and the first microlens 430 pass through the cover glass 200 and the display panel 300 and select the detection target light from the light incident at various incident angles toward the inside of the image sensor layer 100 .

10 (a), the prism sheet 410 includes a first inclined plane 411 and a second inclined plane 412. The first inclined surface 411 and the second inclined surface 412 alternately arranged form a prism mountain and a prism valley. The prism mountain faces the first microlens 430, and the prism valley faces the display.

The first inclined surface 411 of the prism sheet 410 refracts light 322, 323 and 324 incident from the upper left to the lower right and the second inclined surface 412 inclines in the lower left direction from the upper right Refract light. The first inclined surface 411 is inclined between the prism mountain 413a and the prism trough 414b and the second inclined surface 412 is inclined between the prism mountain 413a and the prism trough 414a . 10A, the inclination angle of the first inclined surface 411 with respect to a straight line perpendicular to the upper surface 415 of the prism sheet 400 is θ _P1, and the inclination angle of the first inclined surface 411 is perpendicular to the upper surface 415 of the prism sheet 400 The inclination angle of the second inclined surface 412 with respect to the straight line is? _P2 . In the embodiment shown in the accompanying drawings,? _P1 and? _P2 are expressed differently, but? _P1 and? _P2 may be substantially the same. In the embodiment shown in the accompanying drawings, it is assumed that? _P1 is about 15 degrees to about 20 degrees, and? _P2 is about 30 degrees to 50 degrees. the larger the angle &thetas; _P2 , the larger the amount of light of the detection object light incident on the light receiving portion 520 may increase. The internal angle of the prism object formed by the first inclined plane 411 and the second inclined plane 412 is θ _P1 + θ _P2 and the internal angle θ _P1 + θ _P2 or the prism pitch (ie, the prism mountain 413a) The incident angle to be detected which can be incident on the light receiving portion 520 can be determined according to the distance between the prism trough 413b and the prism trough 414a.

10 (b), the first micro lens 430 refracts the light passing through the prism sheet 410 to direct the image sensor 500 to the lower portion of the image sensor layer 100. The optical path extending layer 420 may be interposed between the first microlens 430 and the image sensor 500 to enhance the incident angle selectivity by the first microlens 430. The thickness of the optical path extending layer 420 may be, for example, about five times the thickness of the central portion of the first microlens 430, but this is merely an example, and the spherical aberration of the first microlens 430, The incident angle can be increased or decreased by various factors such as the angle of incidence. Here, the refractive indexes of the first micro lens 430 and the optical path extending layer 420 may be substantially the same. On the other hand, a light absorbing layer 440 including a light absorbing material may be formed on a portion of the upper surface of the light path extending layer 420 where the first microlenses 430 are not formed. The light absorbing layer 440 may block light having an incident angle other than the incident angle of the detection target from passing through the inside of the optical path extending layer 420 and entering the image sensor 500.

The light blocking layer 450 is interposed between the optical path extending layer 420 and the image sensor 500. At least a part of the upper surface of the light blocking layer 420 is in contact with the lower surface of the light path extending layer 420 and at least a portion of the lower surface of the light blocking layer 420 is in contact with the image sensor 500. As will be described in detail below, a second microlens 530 is formed on the upper surface of the image sensor 500. Therefore, unlike the substantially flat upper surface, the lower surface of the light blocking layer 450 is formed as a concave curved surface corresponding to the concave curved surface of the second microlens 530. [

The optical path extending region 460 extends from the top surface to the bottom surface of the light blocking layer 420 and includes a material having a refractive index different from that of the optical path extending layer 420 or the image sensor 500, , Air, or the like. Due to the optical path extending region 460, the light blocking layer 450 can separate the light selective structure 400 from the image sensor 500 by a predetermined distance.

A plurality of second microlenses 530 corresponding to one first microlens 430 is formed on the upper surface of the image sensor 500. In detail, the prism pitch and the pitch of the first microlenses 430 are substantially the same, and a plurality of second microlenses 530 may be formed within the first microlens pitch. The maximum width of the second microlens 530 may be smaller than the maximum width of the first microlens 430. In the accompanying drawings, a structure in which the ratio of the number of the first microlenses 430 to the number of the second microlenses 530 is 1: 5 or 1:10 is illustrated, but this is merely an example, .

Instead of the general use of a microlens for increasing the amount of light incident on the light receiving portion 520, the image sensor layer 100 may include a first microlens 430 And a second microlens 530 are used. The first microlens 430 is positioned below the prism sheet 410 and is spaced from the prism sheet 410. A material having a refractive index different from the refractive index of the prism sheet 410 or the first microlens 430 can be interposed between the prism sheet 410 and the first microlens 430 . The light to be detected among the light irradiated from the upper surface of the cover glass 200 is made to pass through the appropriately designed optical path by using the difference of the refractive index between the prism sheet and the air and the refractive index between the air and the microlens, So that the light having no light can be deviated from the optical path.

On the other hand, the second microlens 530 is located below the light blocking layer 450 and is spaced from the light path extending layer 420. As described above, the optical path extending region 460 is filled with a material having a refractive index different from that of the optical path extending layer 420 or the image sensor 500, for example, air or the like. Therefore, light incident from the optical path extending layer 420 to the optical path extending region 460 is refracted due to the difference in refractive index between the optical path extending layer 420 and the optical path extending region 460. At least one of the plurality of second microlenses 530 refracts the light to be detected from the refracted light toward the light receiving unit 520 and refracts the light not having the incident angle to be detected to depart from the light receiving unit 520.

The image sensor 500 includes a light receiving portion 520 formed on the substrate 510, a second microlens 530 formed on the upper portion of the light receiving portion 520, and a metal layer (not shown) formed on the upper portion or the lower portion of the light receiving portion 520 ). The light receiving unit 520 is located below the second microlens 530 and detects incident light to generate a pixel current. The generated pixel current can be outputted to the outside by the metal layer.

The center of the first microlens 430, the center of the second microlens 530, and the center of the light receiving unit 520 may not coincide with each other in order to improve the incident angle selectivity. 6, the light receiving unit 520 is located on the lower right side of the second microlens 530, and the second microlens 530 is located on the lower right side of the first microlens 430. Here, the position of the light receiving unit 520 is a position at which the detection subject light finally refracted by the second microlens 530 can reach, and the position of the light receiving unit 520 is the position where the detection object incidence angle, the refractive index of the first microlens 430, The refractive index of the lens 530, the height of the optical path extending layer 420, the height of the optical path extending region 460, the distance between the second microlens 530 and the light receiving portion 520, The center-to-center distance of the center-light-receiving portion 520, and the like. With this arrangement, the incident angle selectivity of the image sensor layer 100 can be improved.

Meanwhile, in order to improve the incident angle selectivity, the width of the light receiving portion 520 may be formed to be relatively narrow as compared with the width of the second microlens 530. When the width of the light receiving portion 520 is large, light having an angle other than the incident angle to be detected can also be detected. Therefore, when the light receiving portion 520 is formed at a position where it can be reached when the detection object light is refracted by the light selecting structure 400 and the second microlens 530, light having an angle other than the incident angle of light to be detected, And reaches the lower surface of the substrate 510 on which the second electrode 520 is not formed. In one embodiment, the width of the light receiving portion 520 may be about 70% or less of the width of the second microlens 530, for example.

And a metal layer for electrical wiring may be formed between the second microlens 530 and the light receiving portion 520 (BSI (Back Surface Illumination) structure). On the other hand, the metal layer formed on the lower part of the light receiving portion 520 can only function as an electric wiring (FSI (Front Surface Illumination) structure). A plurality of metal lines constituting the metal layer transmit control signals to the light receiving unit 520 or form an electric wiring for drawing the pixel current generated by the light receiving unit 520 to the outside. The plurality of metal lines may be electrically insulated from each other by an IMD (Inter Metal Dielectric) or the like. In addition, the optical path defined by a plurality of metal lines may also be formed of IMD. For example, since the light selected by the second microlens 530 slopes incident on the surface of the light receiving unit 520, the optical path may also be formed to be inclined. On the other hand, the optical path can be formed to have a relatively narrow cross-sectional area than that of a general CIS (CMOS Image Sensor) optical path. As another example, the light path defined by the plurality of metal lines may be formed perpendicular to the upper surface of the light receiving portion 520. For reference, a light path having a relatively narrow cross-sectional area is disclosed in Korean Patent Laid-Open Publication No. 10-2016-0048646, which is hereby incorporated by reference in its entirety.

Hereinafter, a method of selecting the detection target light according to the incident angle to the image sensor layer 100 will be described.

FIG. 10B illustrates light 323, 323, and 324 that reaches a different position in the horizontal direction according to the incident angle? To the image sensor layer 100. FIG. The incident angle means an angle between a traveling direction of light when the image sensor layer 100 is incident on the lower surface of the display panel 300 and a straight line perpendicular to the upper surface 415 of the prism sheet 410 .

The light 322 having an incident angle? Larger than the detection object incident angle? ₁ is refracted in the clockwise direction by the first inclined plane 411 and the first microlens 430 of the prism sheet 410. Here, the detection subject incident angle? ₁ is substantially the same as the incident angle of the cover glass when the cover glass 200 is irradiated. The ratio of the light 322 having the incident angle? Larger than the detection object incident angle? ₁ is refracted at the first inclined plane 411 and incident on the first microlens 430 is lower than that of the other lights 323 and 324. Basically, the light 322 can enter between the point f of the first inclined plane 411 and the valley 414b of the prism sheet, which travels from the point f toward the mountain 413a of the first inclined plane 411 This is because the light 322 is blocked by the valleys 414a of the prism sheet 410 located on the left side of the first inclined plane 411. However, the light 322 incident between the point d of the first inclined plane 411 and the valleys 414b of the prism sheet is refracted and directed to the area between the adjacent first microlenses 430. When the light absorbing layer 440 is formed in the region, the refracted light 3221 is blocked by the light absorbing layer 440. The incident light 322 from the point e to the point d is refracted and directed toward the first microlens 430 but the incident angle from the point g to the first microlens 430 increases sharply. 1 refracted light 3221 toward the right side of the microlens 430 is substantially reflected. Accordingly, only the light 322 incident from the point f to the point e of the first inclined plane 411 is refracted by the first microlens 430 and directed toward the image sensor 500. The light 3222 refracted by the first inclined plane 411 and the first microlens 430 is incident on the point f from the point f to the point e of the first inclined plane 411 but faces the point f ₄ , ).

The light 323 having the incident angle of incidence? ₁ is refracted in the clockwise direction from the first inclined plane 411 toward the first microlens 430. Here, since the refractive index of the prism sheet 410 is relatively larger than the refractive index of air, the refraction angle at the first inclined plane 411 is relatively larger than the incidence angle.

The light 3231 emerging from the first inclined plane 411 is refracted toward the image sensor 500 from the first microlens 430. The spherical aberration of the first microlens 430 is determined to be directed to the light receiving unit 520 when the light 323 having the detection subject incident angle? ₁ is refracted by the first inclined plane 411 and is incident. In this case, the angle of incidence of the refracted light 3231 with respect to the first microlens 430 may be substantially 20 degrees or less. The normal line at the point a of the first microlens 430 is substantially equal to the incident angle of the refracted light 3231 so that the light 3231 is directed to the light receiving unit 520 without being refracted. The angle between the normal line and the light 3231 increases in the left direction of the normal line, that is, in the counterclockwise direction from the point a to the point b, and the angle between the normal line and the light 3231 increases from the point a to the point c, That is, clockwise. Accordingly, the light 3231 is refracted in the clockwise direction at the point b to be directed to the image sensor 500, and the light 3231 is refracted in the counterclockwise direction at the point c to be directed to the image sensor 500. Since the angle of incidence of the light 3231 entering the right side at the point b is sharply increased at the incident angle to the first microlens 430, the refracted light 3231 passing through the point b and directed to the right side of the first microlens 430 Substantially reflected. Since the light 3231 is incident on the first microlens 430 through air and the refractive index of air is relatively smaller than the refractive index of the microlens, the refraction angle of the first microlens 430 is smaller than that of the first microlens 430 430). ≪ / RTI >

The light 3232 refracted by the first microlens 430 is incident on the optical path extending region 460 through the lower surface of the optical path extending layer 420 and is reflected toward the second microlens 530 counterclockwise Refracted. Here, since the refractive index of the optical path extending layer 420 is relatively larger than the refractive index of the optical path extending region 460, the refraction angle at the lower surface of the optical path extending layer 420 is relatively larger than the incident angle.

The light 3234 refracted by the second microlens 530 reaches the light receiving portion 520 at the incident angle? ₂ . The spherical aberration of the second microlens 530 is determined to be directed to the light receiving unit 520 when the light 3233 is refracted by the second microlens 530 and is incident.

The light 324 having an incident angle? Smaller than the detection object incident angle? ₁ is refracted toward the first microlens 430 from the first inclined plane 411. [ As the incidence angle? Of the light 324 becomes smaller, the incident angle with respect to the first inclined plane 411 becomes larger. When the incident angle with respect to the first inclined plane 411 is larger than the total reflection angle, the light 324 is totally reflected by the first inclined plane. The light 3241 refracted by the first inclined plane 411 is directed to the left side of the first microlens 430 as the incidence angle? Of the light 324 becomes smaller. The light 3241 incident on the left side of the first microlens 430 is refracted by the first microlens 430 and directed toward the image sensor 500. The light 3242 refracted by the first microlens 430 is directed to point f ₃ , but blocked by the light blocking layer 450.

11 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment. Explanations of substantially the same or similar components as those of FIG. 10 will be omitted, and differences from FIG. 10 will be mainly described.

11 (a) and (b), the image sensor layer 100 includes a light selection structure 400 and an image sensor 500. The optical selection structure 400 is positioned below the display panel 300 and the optical selection structure 400 includes a prism sheet 410a and a first microlens 430. The prism sheet 410a and the first microlens 430 select detection target light from light incident at various incident angles.

11 (a), the prism sheet 410a has a self-aligning and self-supporting structure. Compared with the prism sheet 410 of Fig. 10, the prism sheet 410a has a structure in which the tip portions of the prism mountains are removed. The upper end 411a of the first inclined plane 411 is coupled to the upper end 412a of the second inclined plane 412 to form a prism valley and is substantially parallel to the upper surface 415 of the prism sheet 410a Both ends of the lower surface 416 extending in the lateral direction connect the lower end 411b of the first inclined surface 411 and the lower end 412b of the second inclined surface 412. [ The width of the lower surface 416 may be substantially equal to or smaller than the distance between the adjacent two first microlenses 430. The prism sheet 410a and the first microlens 430 can be aligned only by disposing the lower surface 416 of the prism sheet 410a between the first microlenses 430. [ Further, since the prism sheet 410a can be supported by the substantially flat lower surface 416, a separate structure for supporting or fixing the prism sheet 410a is not required.

12 is a cross-sectional view exemplarily showing a structure for selecting an incident angle by the second microlens.

12, (a) shows a case where light 323 having a detection object incident angle? ₁ is refracted in the first inclined plane 411-first microlens 430-optical path extending region 460, (A), (a2), and (a3) on the lens 530, (b) illustrates a case in which light having a different incident angle is incident on the first inclined plane 411, the first microlens 430, And the incident light is refracted in the path extending region 460 and incident on the same point on the second microlens 530. [ The center of the second microlens 530 and the center of the light receiving unit 520 are not arranged on the same vertical line and the width of the light receiving unit 520 is set to be shorter than the width of the second microlens 530 ) Relative to the width.

Even if the light reaches the second microlens 530 at the same incident angle, the refraction angle of the light 3233 varies depending on the arrival point. The incident angle and the refraction angle at the point a1 are relatively smaller than the incident angle and the refraction angle at the point a, since the point a1 is located on the left side of the point a. Therefore, the refracted light 3234a1 proceeds to the left side of the light receiving portion 520. [ Since the point a2 is located on the right side of the point a, the incident angle and refraction angle at the point a2 are relatively larger than the incident angle and the refraction angle at the point a. Therefore, the refracted light 3234a2 proceeds to the right side of the light receiving portion 520. [ On the other hand, the light that is directed from the point a3 to the right rapidly increases in the incident angle, so that the light 3233 is substantially reflected.

On the other hand, even if the same point on the second microlens 530 is reached, the refraction angle is different if the incident angle is different. At point a, the angle of incidence of the light 3223 is greater than the angle of incidence of the light 3233, which causes the refracted light 3224 to propagate to the right of the light- At point a, the incident angles of the lights 3243 and 3253 are smaller than the incident angle of the light 3233, so that the refracted lights 3244 and 3254 proceed to the left side of the light receiving section 520. [

Therefore, even if a plurality of second microlenses are arranged in the first microlens pitch, the number of light receiving portions 520 for detecting light having an incident angle of light to be detected can be minimized. That is, the light selected by the first inclined plane 411, the first microlens 430, the optical path extending region 460, and the second microlens 530 is incident on the plurality of light receiving portions 520 ). ≪ / RTI > In some cases, two or more light receiving portions 520 may detect light having an incident angle of incidence, or two or more light receiving portions 520 may detect light having an incident angle (one of which is an incident angle of detection) different from each other. However, a difference may occur in the amount of light reaching the light receiving unit 520, so that a difference may also occur in the pixel currents generated by the light receiving units 520. Therefore, the noise caused by the two or more light receiving portions 520 can be removed by an image signal processor (ISP) or the like.

13 is a cross-sectional view illustrating a manner in which light other than the incident angle of incidence is blocked in the image sensor layer of FIG.

13, (a) illustrates a path of light incident vertically toward the image sensor layer 100, or from a right upper portion to a left lower portion, and (b) illustrates a path of light incident on the image sensor layer 100, in which the light absorbing layer 440 is omitted The path of light incident on the structure is illustrated.

the light beams 325a and 325b vertically incident on the image sensor layer 100 are totally reflected by the first inclined plane 411 or the second inclined plane 412 in FIG. The incidence angle of the light 325a incident on the point P11 of the first inclined plane 411 is equal to or greater than the total reflection angle and the incidence angle of the light 325b incident on the point P12 of the second inclined plane 412 is equal to or greater than the total reflection angle. Since the first inclined plane 411 and the second inclined plane 412 are substantially planar, the lights 325a and 325b vertically incident on the image sensor layer 100, regardless of the positions of the points P11 and P12, (411) and the second inclined surface (412). Although not shown, light incident vertically toward the light absorbing layer 440 can be absorbed by the light absorbing layer 440. [

The light 326 having the incident angle? Smaller than the detection object incident angle? ₁ is refracted in the counterclockwise direction from the point P21 on the second slanted surface 412 toward the first microlens 430. [ As the incident angle? Of the light 326 becomes smaller, the incident angle with respect to the second inclined plane 412 becomes larger. Therefore, as the incidence angle? Of the light 326 becomes smaller, the points P22 and 23 where the light refracted by the second inclined surface 412 enter the first microlens 430 move to the right, The focal point of the light refracted by the lens 430 also moves to the right. On the other hand, when the light 326 is refracted by the second inclined plane 412 and incident on the left side of the point P23, the incidence angle with respect to the first microlens 430 increases sharply and is substantially reflected. As shown, since the light path through which the light 326 is passed by the first microlens 430 is on the light blocking layer 450, the light 326 passes through the light receiving portion 520 of the image sensor 500 ). ≪ / RTI >

The light beams 327a and 327b having the detection object incidence angle? ₁ can be refracted in the counterclockwise direction from the point P31 on the second inclined surface 412 toward the first microlens 430. [ Like the detected angle of incidence light 326 having a smaller angle of incidence θ than θ _1, the optical path that the light (327a) is passing by the first micro-lens 430 having a detected incident angle θ ₁ is a light blocking layer (450 The light 327a does not reach the light receiving portion 520 of the image sensor 500. In this case, On the other hand, the light 327a to the left of the point P31 can be refracted by the second inclined plane 412, and the point of incidence on the first microlens 430 is the left side of the point P33. When incident at the left side of the point P33, the incident angle with respect to the first microlens 430 rapidly increases, so that the incident light is substantially reflected. On the other hand, the light 327b incident on the point P32 reaches the point P33 on the first inclined surface 411 and is substantially reflected by the first inclined surface 411. [ The light reflected at the point P33 is incident on the first microlens 430 but enters the first microlens 430 at an incident angle blocked by the light blocking layer 450 as described with reference to FIG.

The light 328 having the incident angle? Larger than the detection object incident angle? ₁ is refracted in the clockwise direction from the second inclined surface 412 toward the first microlens 430. [ The light refracted at the point P41 on the second sloping surface 412 is refracted in the clockwise direction by the first microlens 430 to face the image sensor layer 100 but most of the light is blocked by the light blocking layer 450 . A part of the light not blocked by the light blocking layer 450 can reach the second microlens 530 but is refracted by the second microlens 530. [ At this time, the optical path of the light refracted by the second microlens 530 is different from the optical path of the light having the detection target incident angle? _{1 shown} in FIG. On the other hand, the light refracted at the point P42 on the second inclined plane 412 is incident on the point P43 on the first microlens 430, but is substantially reflected. The light incident on the left side of the point P42 reaches the first inclined plane 411 and is refracted by the first inclined plane 411 to be incident into the prism sheet 410a.

(b), the incident angle selectivity of the structure shown in FIG. 10 or 11 is not affected even when the light absorbing layer 440 is not disposed between the first microlenses 430. The inter-microlens region 441 is an interface between the prism sheet 410a and the optical path extension layer 420, and light passing through the inter-microlens region 441 may be somewhat refracted. However, for convenience of explanation, do.

Most or all of the incidence angle? Larger than the detection incidence angle? ₁ causes the light 322 having the incidence angle to be directed to the first inclined plane 411. Therefore, such light 322 does not enter the inter-microlens region 441. [ On the other hand, at least a part of the incident angle? Smaller than the detection object incident angle? ₁ directs the light 324 having the incident angle to the inter-microlens region 441. However, most of the light 324 is blocked by the light blocking layer 450. Further, when passing through the left side of the point P5 on the inter-microlens region 441, the light 323 having the detection object incident angle? ₁ is blocked by the light blocking layer 450 as well.

Some of the light 324, a detection subject incident angle θ ₁ having a portion and the target angle of incidence smaller than the angle of incidence θ ₁ θ of the light 323 may be incident on the optical path extending region 460. The However, when the light refracted by the first microlens 430 enters the optical path extending region 460, the light enters the optical path extending region 460 at a different incident angle. Therefore, it is incident on the second microlens 530 in a path different from that of the light having the detection object incident angle? ₁ shown in FIG. 6 or reflected at the interface of the light path extending layer-light path extending region.

On the other hand, a part of the light 325 vertically incident on the inter-microlens region 441 is blocked by the light blocking layer 450, but the remaining unblocked light is vertically incident on the second microlens 530 . The incident light is focused on the focal point by the second microlens 530. However, since the light receiving unit 520 is spaced from the center of the second microlens 530 and the width of the light receiving unit 520 is also relatively small, the light focused on the focus is not detected by the light receiving unit 520. That is, since the light receiving unit 520 is not aligned with the center of the microlenses 430 and 530, it is possible to eliminate or reduce the influence of the rectilinear light.

14 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment. Explanations of components substantially the same as or similar to those of Figs. 10 and 11 will be omitted, and differences from Figs. 10 and 11 will be mainly described.

Referring to Figure 14, a cross-section of the edge portion of the image sensor layer 100 is shown. The lower surface of the light blocking layer 451 is substantially flat and only a part of the lower surface of the light blocking layer 451 is in contact with the second microlens 530, unlike the light blocking layer 450 shown in FIG. 10 or 11 . The light blocking layer 451 is not in close contact with the second microlens 530 but the light is blocked by the top surface of the light blocking layer 451 so that no difference in function occurs.

Outer spacers 451a and 451b are formed between the image sensor 500 and the optical selection structure 400 to separate the image sensor 500 from the optical selection structure 400 by a certain distance. The light blocking layer 451 directly contacts the second microlenses 530 but the second microlenses 530 may not be formed in the regions where the outer spacers 451a and 451b are located.

The height of the light blocking layer 451 and the outer spacers 451a and 451b may be different and the outer spacers 451a and 451b may be formed higher than the light blocking layer 451. [ 11, (b) may be omitted, and a process of increasing the height of the area corresponding to the outer spacers 451a and 451b may be added. 14, the outer spacers 451a are formed simultaneously with the light blocking layer 451, and the outer spacers 451b may be formed by depositing a light blocking material in an area where the outer spacers 451a are formed. Here, the height of the outer spacers 451b may be substantially the same as the maximum height of the second microlenses 530.

15 is a cross-sectional view exemplarily showing a section of an image sensor layer according to another embodiment. 10, 11, and 14 are omitted, and differences from FIGS. 10, 11, and 14 are mainly described.

10 and 11, it can be seen that light not having an incident angle of detection is blocked by the light blocking layer 450, but is concentrated at a position different from that of the detection object light even if it progresses without being blocked. Therefore, even if only the optical path including the first inclined plane 411 - the first microlens 430 - the optical path extending region 460 - the second microlens 530 of the prism sheet 410 is sufficiently detected . However, in the structure in which the light blocking layer 450 is not provided, there is a possibility that light having an incident angle other than the detection subject incident angle reaches the one or more light receiving portions due to various factors

15B shows an array of light receiving portions through which light having passed through one first inclined plane 411 and one first microlens 430 can reach.

In order to indicate that the light quantity of incident light differs, each light receiving section is displayed in a pattern having a different interval. Here, as the interval of the pattern is narrower, a relatively large amount of light is concentrated, and as the interval is wider, a relatively small amount of light is concentrated. Referring to FIG. 15 (a), it can be seen that a larger amount of light is concentrated in the light-receiving units R3 and C3 than in the other light-receiving units in the vicinity. Light receiving portions R2 and C3 and R4 and C3 located on the same column as the light receiving portions R3 and C3 have a relatively small amount of light as compared with the light receiving portions R3 and C3, The light receiving portion located at a relatively small amount of light is concentrated compared to the light receiving portions R2, C3 and R4, C3.

That is, even though the light having passed through one first inclined surface 411 and one first microlens 430 reaches a plurality of light receiving portions, the amount of light concentrated for each light receiving portion becomes different. The magnitude of the pixel current generated by the light-receiving unit is substantially proportional to the amount of concentrated light. Therefore, a clear fingerprint image can be generated by selecting only the maximum pixel current in the CIS, or a clear fingerprint image can be generated through the image signal processing at the end of the CIS.

16 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment. Explanations of substantially the same or similar components as those of FIG. 10 will be omitted, and differences from FIG. 10 will be mainly described.

16 (a) and 16 (b), the image sensor layer 100 includes a light selection structure 400 and an image sensor 500. The optical selection structure 400 is located below the display panel 300 and the optical selection structure 400 includes a prism sheet 410 and a microlens 430. The prism sheet 410 and the microlens 430 pass through the cover glass 200 and the display panel 300 and select the light to be detected from the light incident at various incident angles toward the inside of the image sensor layer 100.

16A, the first inclined surface 411 of the prism sheet 410b refracts light 322, 323, and 324 incident in the lower right direction from the upper left side, and the second inclined surface 412 refracts the light 322, And cuts off light incident on the upper left side in the lower direction. To this end, a light absorbing layer containing a light absorbing material may be formed on the surface of the second inclined surface 412. The light absorbing layer formed on the surface of the second inclined surface 412 absorbs light incident in the lower left direction from the upper right portion. As a result, light having an angle other than the angle of incidence of the detection object can not reach the light-receiving unit 520.

16 (b), the microlens 430 refracts the detection target light among the light that has passed through the prism sheet 410b and directs it to the light receiving unit 520. [ The microlens 430 is formed on the upper portion of the light receiving portion 520 of the image sensor 500 having the metal layer 540 corresponding to the optical path 545 defined by the plurality of metal lines. That is, the microlens 430 is positioned below the prism sheet 410 and is spaced from the prism sheet 410. Thereby, air is interposed between the prism sheet 410 and the microlens 430. The light to be detected irradiated from the upper surface of the cover glass 200 can be selected using the difference between the refractive index of the prism sheet and the air and the refractive index between the air and the microlens.

The image sensor 500 includes a substrate 510, a light receiving portion 520 formed on the substrate 510, and a metal layer 540 formed on the light receiving portion 520 and defining a light path 535.

The light receiving unit 520 is positioned below the microlens 430 and detects incident light to generate a pixel current. A metal layer 540 for electrical wiring is formed between the microlens 430 and the light receiving unit 520, forming an optical path 545.

The metal layer 540 may be formed under the microlens 430. The plurality of metal lines constituting the metal layer 540 transmit control signals to the light receiving unit 520 or form an electric wiring for drawing the pixel current generated by the light receiving unit 520 to the outside. Although not shown, the metal layer 540 may be formed on the substrate 510 under the light receiving unit 520. That is, not only a CIS having a BSI (Back Surface Illumination) structure but also a CIS having a FSI (Front Surface Illumination) structure can realize a display having a fingerprint recognition function.

17 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment. 10, 11, and 16 will be omitted, and differences from FIGS. 10, 11, and 16 will be mainly described.

Referring to Figures 17A and 17B, the image sensor layer 100 includes a light selection structure 400 and an image sensor 500. The optical selection structure 400 is positioned below the display panel 300 and the optical selection structure 400 includes a prism sheet 410c and a microlens 430. [ The prism sheet 410c and the microlens 430 select detection target light among light incident at various incident angles.

17 (a), the prism sheet 410a has a self-aligning and self-supporting structure. Compared with the prism sheet 410b in Fig. 16, the prism sheet 410a has a structure in which the tip portions of the prism mountains are removed. The upper end 411a of the first inclined plane 411 is coupled to the upper end 412a of the second inclined plane 412 to form a prism valley and is substantially parallel to the upper surface 415 of the prism sheet 410a Both ends of the lower surface 416 extending in the lateral direction connect the lower end 411b of the first inclined surface 411 and the lower end 412b of the second inclined surface 412. [ The width of the lower surface 416 may be substantially equal to or less than the distance between the microlenses 430. The prism sheet 410a and the microlens 430 can be aligned only by disposing the lower surface 416 of the prism sheet 410a between the microlenses 430. [ Further, since the prism sheet 410a can be supported by the substantially flat lower surface 416, a separate structure for supporting or fixing the prism sheet 410a is not required.

18 is a cross-sectional view exemplarily showing a cross section of an image sensor layer according to another embodiment. 11 and 17 will be omitted, and differences from FIGS. 11 and 17 will be mainly described.

Referring to FIG. 18, the image sensor layer 100 includes a light selection structure 400 and an image sensor 500. The optical selection structure 400 is positioned below the display panel 300 and the optical selection structure 400 includes a prism sheet 410a and a microlens 430. [ The prism sheet 410a and the microlens 430 select detection target light from light incident at various incident angles.

The prism sheet 410a has a self-aligning and self-supporting structure. As described above, the light absorbing layer formed on the second inclined surface 412 in Fig. 16 or 17 absorbs the light 327 incident in the lower left direction from the upper right portion, and the light in this direction absorbs the light toward the image sensor 500 Do not join the company. A part of the light 327 incident on the image sensor layer 100 from the upper right portion to the lower left portion is refracted by the second inclined surface 412 of the prism sheet 410a to be incident on the microlens 430 . However, the refracted light 327 must be absorbed by the absorbing layer 470b and not incident on the image sensor 500. [

At least one light absorbing layer 470a, 470b is formed in the light path extending layer 420 to block the light 327 incident in the lower right direction from the upper right. In one embodiment, the light absorbing layers 470a and 470b are formed of light absorbing materials that absorb light, and extend in the lateral direction. In another embodiment, the light absorbing layers 470a and 470b are formed of metal and extend in the lateral direction. Additionally, the upper surface of the metal may be coated with a light absorbing material that absorbs visible light or infrared light. The light-absorbing material coated on the metal can absorb the light reflected on the metal. The light absorbing layers 470a and 470b are formed on the surface of the light path extending layer 420 after forming the light path extending layer 420 at a predetermined ratio of the target thickness, for example. Then, a light path extension layer 420 is formed on the upper side of the light absorbing layers 470a and 470b to a target thickness. The plurality of light absorbing layers 470a and 470b as shown may be implemented by repeatedly forming the light path extending layer-light absorbing layer.

The light absorbing layers 470a and 470b formed in the light path extending layer 420 may define a light path for the light to be detected. In some areas of the light absorbing layers 470a and 470b, openings 471 for defining optical paths are formed. The width of the opening 471 is determined so that the light to be detected refracted by the microlens 430 can pass through. Therefore, in the structure in which the light path is defined by the light absorbing layers 470a and 470b, the light path 546 by the metal layer 540 may not be defined in the image sensor 500. [ In other words, even if the image sensor 500 in which the optical path 546 is formed vertically is used, sufficient light incident angle selectivity can be ensured by the optical path extending layer 420.

FIG. 19 is a sectional view exemplarily showing a cross section of a display having a fingerprint recognition function according to another embodiment. Explanations of components substantially the same as or similar to those of Figs. 10 to 18 are omitted, and differences from Figs. 10 to 18 are mainly described.

Referring to FIG. 19, a display having a fingerprint recognition function includes a display panel 300 'and an image sensor 500. The image sensor 500 is positioned below the display panel 300 ', and the light selection structure 400 of FIGS. 10 to 18 is implemented in the display panel 300'. The display panel 300 allows the detection target light 323 to pass through the light incident from the cover glass 200 but prevents the lights 322 and 325 having the other incident angles from reaching the light receiving unit 520.

The display panel 300 'includes a pixel defining layer 370 defining a pixel 360 and a region where the pixel is to be positioned. An opening is formed in a part of the pixel defining layer 370, and a pixel 360 is formed in the opening. In the case of an OLED, a light emitting portion is formed in the opening. The pixel defining layer 370 may be formed using various insulating materials. Here, the insulating material may be transparent to visible light and / or near infrared rays. On the other hand, the TFT for driving the pixel 360 and the electric wiring may be disposed inside the pixel defining film or below the pixel 360. [ The light shielding layer 361 may be formed under the pixel 360. On the other hand, the light shielding layer 361 prevents light generated in the pixel 360 and light passing through the pixel 360 from entering downward.

In one embodiment, a light path 375 extending in the substantially same direction as the traveling direction of the light to be detected may be formed inside the pixel defining layer 370. The optical path 375 may be formed to be inclined with respect to the image surface of the image sensor 500 by an incident angle of the detection target. The optical path 375 may be formed by one or more optically opaque materials. 19 illustrates two optical path defining layers 374 stacked in the vertical direction. The light path defining layer 374 includes openings formed in some regions to define the light path 375. [ The centers of the openings formed in each of the light path defining layers 374 do not coincide with each other in the vertical direction. The light path defining layer 374 may be an electrode and / or a wiring for driving the pixel. On the other hand, the light path defining layer 374 may be formed of a light absorbing material.

In another embodiment, the upper surface 371 and the side surface 372 of the pixel defining layer 370 may be connected by the incident surface 373. The incident surface 373 may be formed to be substantially perpendicular to the traveling direction of the detection target light 323. The incident surface 373 can reduce the amount of refraction or reflection of the light to be detected on the surface of the pixel defining layer 370. [ In addition, when a refractive index difference is generated based on the surface of the pixel defining layer 370, light traveling at an incident angle other than the detection object incident angle may be refracted to prevent the light receiving portion 520 from reaching the object.

19 shows an inclined optical path 545 defined by the metal layer 540 of the image sensor 500. [ However, when the incident angle selectivity of the display panel 300 'is sufficiently high, an image sensor 500 having a vertical optical path as shown in FIG. 18 may be applied.

The display having the fingerprint recognition function described with reference to FIGS. 1 to 18 has a structure in which an image sensor layer 100 for generating a fingerprint image and a display panel 300 for outputting an image are combined. Therefore, even if a finger is placed at an arbitrary point on the cover glass 200, a fingerprint image can be generated. A fingerprint sensor package having substantially the same function and structure as the image sensor layer 100 can generate a fingerprint image of a finger located at a predetermined point on the cover glass 200. [

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

It is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. .

Claims (12)

In a display having a fingerprint recognition function,
A display panel disposed at a lower portion of the cover glass, through which light having various incident angles representing ridges and valleys of the finger contacting the cover glass passes; And
And an image sensor layer disposed at a lower portion of the display panel to detect a detection subject light having an incident angle of light to be detected from light having various incident angles to generate a fingerprint image,
Wherein the ridge is a point light source for irradiating the light diffused through the skin of the finger toward the image sensor layer when the finger contacts the cover glass. The display of claim 1, wherein the light diffused through the skin of the finger is generated by ambient light. The display according to claim 1, wherein the light diffused through the skin of the finger is generated by the panel light illuminated by the display panel. The image sensor of claim 1,
A light selecting structure for selecting the detection subject light from light having the various incident angles; And
And an image sensor disposed at a lower portion of the optical selection structure for generating the fingerprint image using the detection target light. 5. The optical pick-up apparatus according to claim 4,
A prism sheet for refracting the light having the detection object incidence angle at a first angle among the lights having the various incident angles; And
And a microlens located at a lower portion of the prism sheet and refracting light refracted at a first angle to a second angle. The display according to claim 5, further comprising a light path extending layer interposed between the microlens and the image sensor. The image sensor according to claim 5,
And a light receiving unit positioned below the microlens and generating a pixel current corresponding to light refracted at the second angle,
Wherein the light receiving unit is located at a lower side of the microlens. 6. The prism sheet according to claim 5,
A plurality of first inclined surfaces and a plurality of second inclined surfaces alternately arranged to form prism mountains and prism valleys,
Wherein the first inclined surface refracts light having the detection object incidence angle at a first angle out of light having the various incidence angles,
Wherein the inclination angle of the first inclined surface is smaller than the inclination angle of the second inclined surface. 5. The optical pick-up apparatus according to claim 4,
A prism sheet including a plurality of first inclined surfaces and a plurality of second inclined surfaces arranged alternately so as to form prism valleys and refracting light having the detection object incidence angle at a first angle among lights having the various incident angles; And
And a microlens located at a lower portion of the prism sheet and refracting the light refracted at the first angle to a second angle,
Wherein an upper end of the first inclined surface is connected to an upper end of the second inclined surface,
And a lower end of the first inclined surface and a lower end of the second inclined surface are connected to both ends of a lower surface extending in parallel, respectively. The display according to claim 9, further comprising a light path extending layer interposed between the microlens and the image sensor. 5. The optical pick-up apparatus according to claim 4,
A prism sheet for refracting the light having the detection object incidence angle at a first angle among the lights having the various incident angles; And
And a first microlens located at a lower portion of the prism sheet for refracting light refracted at a first angle to a second angle,
Wherein the image sensor comprises:
And a second microlens located on an upper surface of the image sensor and refracting light refracted at a second angle to a third angle. 5. The image sensor of claim 4, wherein the image sensor is formed of a thin film transistor,
Wherein the image sensor layer is formed on at least a part or the entire area of the lower surface of the display panel.

Images