Fingerprint sensor

Abstract

An embodiment of the present disclosure relates to a fingerprint sensor, the fingerprint sensor comprising: a substrate; a light blocking layer on a first surface of the substrate and including an opening in a light blocking mask; and a sensor layer on a second surface of the substrate and including a light sensor. A fingerprint sensing method of the fingerprint sensor comprises: storing a calibration image; generating an original image based on a sensing signal from the light sensor; performing calibration on the original image by using the calibration image; and detecting a fingerprint based on the calibrated image. The calibration image is generated by synthesizing a valid area extracted from an original calibration image corresponding to the original image.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0105124 filed on August 27, 2019, in the Korean Intellectual Property Office (KIPO), the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] One or more aspects of embodiments of the present disclosure generally relate to a fingerprint sensing method, a fingerprint sensor, and a display device including the fingerprint sensor. Background Art

[0004] The photosensitive fingerprint sensor may include a light source and a light sensor. Each light sensor may receive reflected light generated by the user's fingerprint, and the fingerprint detector may detect the fingerprint by generating and processing a raw image based on the reflected light.

[0005] Due to the deviation of the light sensor (and the light path), the reflected light received by the light sensor may include noise, or the original image may include noise (or error). In order to remove the noise from the original image, the fingerprint detector may perform white calibration (or calibration) on the original image. For example, by using a white calibration image (or calibration data) pre-generated / pre-stored based on the ambient light received by the light sensor, the fingerprint detector can calibrate the original image.

[0006] The optical structure may be disposed on an optical path between the user's fingerprint and the optical sensor, and according to the deployment position of the optical structure (e.g., the distance from the optical structure to the fingerprint and the distance from the optical structure to the optical sensor), the reflected light generated by the fingerprint may be provided to only some of the optical sensors located in the sensing area. That is, the substantially effective area (i.e., the effective area) for fingerprint detection may be limited to only a portion in the original image. However, a white calibration image with respect to the entire sensing area may be stored, which may increase the storage space and loading time of the white calibration data. Summary of the invention

[0007] Aspects of some example embodiments are directed to a fingerprint sensing method, a fingerprint sensor, and a display device including the fingerprint sensor, which may minimize or reduce a storage space of a white calibration image and reduce a loading time of the white calibration image.

[0008] Aspects of some example embodiments are directed to a fingerprint sensing method, a fingerprint sensor, and a display device including the fingerprint sensor, which may reduce a time to perform white calibration on a raw image acquired through a light sensor (ie, a time required to perform white calibration).

[0009] One or more example embodiments of the present disclosure provide a fingerprint sensor, comprising: a substrate; a light blocking layer, on a first surface of the substrate, the light blocking layer including an opening in a light blocking mask; a sensor layer, on a second surface of the substrate, the sensor layer including a light sensor; and a fingerprint detector configured to generate a raw image based on a sensing signal from the light sensor, perform calibration on the raw image by using a calibration image, and detect a fingerprint based on the calibrated image, wherein the calibration image is generated by synthesizing a valid area extracted from a raw calibration image corresponding to the raw image.

[0010] The light blocking layer may transmit first light incident thereto to the sensor layer through the opening and block second light.

[0011] A first light sensor of the light sensors may receive light through one opening, and a second light sensor of the light sensors may not receive light or receive light through two or more openings.

[0012] The active area may be generated based on a sensing signal from a first light sensor among the light sensors configured to receive light through an opening.

[0013] The original calibration image may be generated based on a sensing signal output from the light sensor in response to skin-colored light.

[0014] The calibration image may be generated by extracting the valid area in the original calibration image and stitching the valid area.

[0015] The calibration image may have a smaller capacity than that of the original calibration image.

[0016] The fingerprint detector may extract the valid area in the original image, generate a composite image by splicing the extracted valid areas, and perform calibration on the composite image by using the calibration image.

[0017] The fingerprint detector may perform the calibration by loading the calibration image and subtracting the calibration image from the composite image.

[0018] The fingerprint detector may perform at least one image processing of smoothing, binarization, and thinning on the effective area or the synthesized image.

[0019] The fingerprint sensor may further include: a circuit element layer on the light blocking layer, the circuit element layer having at least one conductive layer constituting a circuit element; and a light emitting element layer on the circuit element layer, the light emitting element layer including a light emitting element.

[0020] One or more example embodiments of the present disclosure provide a fingerprint sensing method of a fingerprint sensor, the fingerprint sensor including a substrate, a light blocking layer on a first surface of the substrate and including an opening in a light blocking mask, and a sensor layer on a second surface of the substrate and including a light sensor, the fingerprint sensing method including: storing a calibration image; generating an original image based on a sensing signal from the light sensor; performing calibration on the original image by using the calibration image; and detecting a fingerprint based on the calibrated image, wherein the calibration image is generated by synthesizing a valid area extracted from an original calibration image corresponding to the original image.

[0021] The effective area may be an area generated based on a sensing signal from a first light sensor among the light sensors configured to receive light through one opening.

[0022] The original calibration image may be generated based on a sensing signal output from the light sensor in response to skin-colored light.

[0023] The calibration image may be generated by extracting the valid area in the original calibration image and stitching the valid area.

[0024] The execution of the calibration may include: extracting the valid area in the original image; generating a composite image by stitching the extracted valid areas; loading the calibration image; and subtracting the calibration image from the composite image.

[0025] The fingerprint sensing method may further include performing at least one image processing of smoothing, binarization, and thinning on the effective area or the synthesized image before loading the calibration image.

[0026] One or more example embodiments of the present disclosure provide a display device, comprising: a substrate; a light blocking layer on a first surface of the substrate, the light blocking layer comprising an opening in a light blocking mask; a circuit element layer on the light blocking layer, the circuit element layer having at least one conductive layer in which circuit elements are arranged; a light emitting element layer on the circuit element layer, the light emitting element layer comprising light emitting elements; a sensor layer on a second surface of the substrate, the sensor layer comprising a light sensor; and a fingerprint detector configured to generate an original image based on a sensing signal from the light sensor, perform calibration on the original image by using a calibration image, and detect a fingerprint based on the calibrated image, wherein the calibration image is generated by synthesizing a valid area extracted from an original calibration image corresponding to the original image.

[0027] The effective area may be an area generated based on a sensing signal from a first light sensor among the light sensors configured to receive light through one opening.

[0028] The original calibration image may be generated based on a sensing signal output from the light sensor in response to skin-colored light. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will convey the scope of the example embodiments to those skilled in the art.

[0030] In the accompanying drawings, the dimensions may be exaggerated for clarity of illustration. It will be understood that when an element is referred to as being "between" two elements, it can be the only element between the two elements, or one or more intermediate elements may also be present. Throughout the text, the same reference numerals represent the same elements.

[0031] Figure 1 and Figure 2 is a schematic plan view showing a display device according to some embodiments of the present disclosure.

[0032] FIG. 3A to FIG. 3E is a plan view showing an arrangement structure of pixels and light sensors according to some embodiments of the present disclosure.

[0033] Figure 4 is a schematic cross-sectional view of a display panel according to some embodiments of the present disclosure.

[0034] Figure 5 is a plan view showing a light blocking layer according to some embodiments of the present disclosure.

[0035] Figure 6 is a schematic cross-sectional view of a display panel according to some embodiments of the present disclosure.

[0036] Figure 7 is a schematic cross-sectional view of a display panel according to some embodiments of the present disclosure.

[0037] Figure 8 is a schematic cross-sectional view of a display panel according to some embodiments of the present disclosure.

[0038] Fig. 9 is a block diagram illustrating a configuration of a fingerprint detector according to some embodiments of the present disclosure.

[0039] Figures 10 to 12 is a view illustrating a method of generating a white calibration image according to some embodiments of the present disclosure.

[0040] Figures 13 to 17 is a view illustrating a method of processing an original image according to some embodiments of the present disclosure.

[0041] Fig.18 is a flow chart illustrating a fingerprint sensing method of a fingerprint sensor according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0042] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Throughout the accompanying drawings, the same reference numerals are assigned to the same elements, and their repeated descriptions may be omitted.

[0043] Figure 1 and Figure 2 is a plan view schematically showing a display device according to some embodiments of the present disclosure. For example, Figure 1 and Figure 2 2 is a view schematically showing a display panel 110 provided in a display device 10 and a driving circuit 200 for driving the display panel 110 according to some embodiments of the present disclosure. Figure 1 and Figure 2 The display panel 110 and the driving circuit 200 are separated from each other, but the present disclosure is not limited thereto. For example, all or part of the driving circuit 200 may be implemented integrally with the display panel 110 (eg, implemented as an integral structure on the display panel 110).

[0044] refer to Figure 1 and Figure 2 The display device 10 includes a display panel 110 and a driving circuit 200 for driving the display panel 110 .

[0045] The display panel 110 includes a display area AA and a non-display area NA. The display area AA (which may be referred to as an active area) is an area in which a plurality of pixels PXL (which may be referred to as sub-pixels) are provided. In some embodiments, each pixel PXL may include at least one light emitting element. Corresponding to image data input from the outside, the display device 10 drives the pixels PXL to display an image in the display area AA.

[0046] In some embodiments of the present disclosure, the display area AA may include the sensing area SA. The sensing area SA may include at least some pixels PXL among the pixels PXL provided in the display area AA.

[0047] In some embodiments, Figure 1 As shown in , at least a portion of the display area AA may be set as the sensing area SA. Figure 2 As shown in , the entire display area AA can be set as the sensing area SA.

[0048] Despite Figure 1 Only one sensing area SA is formed on (or in) the display area AA in the embodiment of the present disclosure, but the embodiments of the present disclosure are not limited thereto. For example, in some embodiments, a plurality of sensing areas SA arranged regularly or irregularly may be formed on (or in) the display area AA. In some embodiments, the plurality of sensing areas SA may have the same or different areas and shapes from each other.

[0049] Despite Figure 1 In the embodiment, the sensing area SA is formed in at least a portion of the display area AA, but the embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the display area AA and the sensing area SA may be provided to overlap each other in at least a partial area.

[0050] The non-display area NA is an area disposed at the periphery of the display area AA and may be referred to as a non-active area. In some embodiments, the non-display area NA may include other areas other than the display area AA on the display panel 110. In some embodiments, the non-display area NA may include a line area, a pad area, various dummy areas, and the like.

[0051] In some embodiments of the present disclosure, the display device 10 may further include a plurality of light sensors PHS provided in the sensing area SA. In some embodiments, each light sensor PHS may sense reflected light generated when light emitted from a light source (e.g., a pixel PXL) is reflected by a user's finger, and the display device 10 may sense a fingerprint of the user's finger by analyzing the reflected light. Hereinafter, although an example of using the light sensor PHS for fingerprint sensing is described, the light sensor PHS may be used to perform various functions such as a touch sensor or a scanner.

[0052] In some embodiments of the present disclosure, the light sensor PHS may be arranged or provided in the sensing area SA. The light sensor PHS may overlap with at least some or all of the pixels PXL provided in the sensing area SA, or may be arranged at the periphery of the pixels PXL. For example, at least some or all of the light sensor PHS may be provided between the pixels PXL. FIG. 3A to FIG. 3E Some embodiments of the arrangement relationship between the photosensors PHS and the pixels PXL are described in more detail.

[0053] In some embodiments, the light sensor PHS is provided adjacent to the pixel PXL, and the light sensor PHS may use a light emitting element as a light source, and the light emitting element is provided in at least one pixel PXL disposed in the sensing area SA or disposed in the periphery thereof. Therefore, the light sensor PHS together with the pixel PXL of the sensing area SA, especially the light emitting element provided in the pixel PXL, may constitute a light-sensitive fingerprint sensor. As described above, when a display device with a built-in fingerprint sensor is configured using the pixel PXL as a light source without any external light source, the module thickness of the light-sensitive fingerprint sensor and the display device with the light-sensitive fingerprint sensor may be reduced, and the manufacturing cost may be reduced.

[0054] In some embodiments, the light sensor PHS may be arranged or provided on the other surface (e.g., rear surface) of the two surfaces of the display panel 110, which is opposite to (e.g., facing away from) the surface (e.g., front surface) on which an image is displayed. However, embodiments of the present disclosure are not limited thereto.

[0055] The driving circuit 200 may drive the display panel 110. For example, the driving circuit 200 may output a data signal corresponding to image data to the display panel 110 or output a driving signal for the light sensor PHS, and receive a sensing signal received from the light sensor PHS. The driving circuit 200 receiving the sensing signal may detect a fingerprint (or fingerprint shape) of a user by using the sensing signal.

[0056] In some embodiments of the present disclosure, the driving circuit 200 may include a panel driver 210 and a fingerprint detector 220. Figure 1 and Figure 2 The panel driver 210 and the fingerprint detector 220 are separated from each other, but the embodiments of the present disclosure are not limited thereto. For example, at least a portion of the fingerprint detector 220 may be integrated with the panel driver 210 or operate in conjunction with the panel driver 210.

[0057] The panel driver 210 may supply data signals corresponding to image data to the pixels PXL while sequentially scanning the pixels PXL of the display area AA. Then, the display panel 110 may display an image corresponding to the image data.

[0058] In some embodiments, the panel driver 210 may supply a driving signal (e.g., a first driving signal) for fingerprint sensing to the pixel PXL. The driving signal may be provided to allow the pixel PXL to serve as a light source for the light sensor PHS by emitting light. Thus, the driving signal for fingerprint sensing may be provided to the pixel PXL provided in a specific area of ​​the display panel 110, for example, the pixel PXL provided in the sensing area SA. In some embodiments, the driving signal for fingerprint sensing may be provided by the fingerprint detector 220.

[0059] The fingerprint detector 220 may provide or transmit a driving signal (eg, a second driving signal) for driving the optical sensor PHS to the optical sensor PHS, and detect the fingerprint of the user based on the sensing signal received from the optical sensor PHS. Figures 9 to 17 A detailed fingerprint detection method of the fingerprint detector 220 is described in detail.

[0060] FIG. 3A to FIG. 3E are plan views showing some embodiments of arrangement structures of pixels and light sensors. FIG. 3A to FIG. 3E Various embodiments of relative size, resolution, and arrangement relationship between at least one pixel PXL and the photosensor PHS provided in the sensing area SA are shown.

[0061] refer to Figure 3A , the light sensors PHS may be arranged to have a resolution (density) equal to or substantially equal to the resolution (density) of the pixels PXL located in the sensing area SA. In other words, light sensors PHS equal to or substantially equal to the number of pixels PXL may be arranged in the sensing area SA. In some embodiments, the pixels PXL and the light sensors PHS may be arranged to form pairs, respectively. Figure 3A In some embodiments shown in , the case where the pixel PXL and the light sensor PHS are arranged to overlap each other is shown. However, in some embodiments, the pixel PXL and the light sensor PHS may be arranged not to overlap each other or to overlap each other only in one area.

[0062] Despite Figure 3A The light sensor PHS has a size smaller than that of the pixel PXL, but the embodiments of the present disclosure are not limited thereto. For example, each light sensor PHS may be larger than each pixel PXL, such as Figure 3C In some embodiments, the light sensor PHS may have a size equal to, substantially equal to, or greater than that of the pixel PXL.

[0063] refer to FIG. 3B to FIG. 3E, the light sensors PHS may be arranged to have a resolution lower than that of the pixels PXL located in the sensing area SA. In other words, a smaller number (or fewer) of light sensors PHS than the number of pixels PXL may be arranged in the sensing area SA. FIG. 3B to FIG. 3E One light sensor PHS is disposed for every four pixels PXL, but the embodiments of the present disclosure are not limited thereto.

[0064] In some embodiments, the light sensor PHS may have a size smaller than that of the pixel PXL, such as Figure 3B and Figure 3E or having a size larger than the size of the pixel PXL, as shown in Figure 3C and Figure 3D as shown in .

[0065] When the light sensor PHS is arranged to have a resolution lower than that of the pixel PXL, some or all of the light sensors PHS may be arranged to overlap with the pixel PXL. For example, the light sensor PHS may partially overlap with some of the pixels PXL, such as Figure 3B and Figure 3C as shown in .

[0066] In some embodiments, the light sensor PHS may be disposed between the pixels PXL, such as Figure 3D As shown in , the pixel PXL is partially overlapped. Figure 3D When viewed in the plan view shown in , one or more portions of each photosensor PHS may overlap with one or more pixels PXL, and one or more other portions of each photosensor PHS may not overlap with one or more pixels PXL. In some embodiments, the photosensor PHS (e.g., each photosensor PHS) may have a size larger than that of the pixel PXL (e.g., each pixel PXL), such as Figure 3D For example, the photosensor PHS (eg, each photosensor PHS) may have a size large enough to cover at least one pixel PXL.

[0067] In some embodiments, the light sensor PHS may not overlap with the pixel PXL. Figure 3E In some embodiments, when Figure 3E When viewed in the plan view shown in , no portion of the photosensor PHS overlaps with the pixel PXL.

[0068] In some embodiments of the present disclosure, the arrangement structure between the pixels PXL and the light sensors PHS is not limited to the arrangement structure described above. That is, the shape, arrangement, relative size, number and resolution of the pixels PXL and the light sensors PHS located in the sensing area SA can be modified differently in an appropriate manner without departing from the technical concept of the present disclosure. In addition, in some embodiments of the present disclosure, the pixels PXL and the light sensors PHS can be arranged to be connected to the sensing area SA by combining the pixels PXL and the light sensors PHS. FIG. 3A to FIG. 3E The form obtained by one or more embodiments shown in .

[0069] Despite FIG. 3A to FIG. 3E In the embodiment, the light sensors PHS are regularly arranged (eg, arranged in a certain pattern) in the sensing area SA, but the embodiments of the present disclosure are not limited thereto. In some embodiments, the light sensors PHS may be irregularly arranged in the sensing area SA.

[0070] Figure 4 is a schematic cross-sectional view of a display panel according to some embodiments of the present disclosure. In particular, Figure 4 It shows that Figure 1 and Figure 2 0 is a cross-sectional view of the display device 10 in the sensing area SA shown in FIG.

[0071] refer to Figure 4 , the sensing area SA of the display device 10 according to some embodiments of the present disclosure may include a display panel 110 and a sensor layer PSL disposed on one surface of the display panel 110. In addition, the display device 10 may include a substrate SUB and a circuit element layer BPL, a light emitting element layer LDL, a first protective layer PTL1, a first adhesive layer ADL1, and a window WIN sequentially disposed on one surface (e.g., an upper surface) of the substrate SUB. In addition, the display device 10 may include a second adhesive layer ADL2 and a second protective layer PTL2 sequentially disposed on another surface (e.g., a lower surface) of the substrate SUB.

[0072] The substrate SUB is a base substrate of the display panel 110 and may be a transparent or substantially transparent transmissive substrate. The substrate SUB may be a rigid substrate including glass or tempered glass, or a flexible substrate made of plastic. However, the material of the substrate SUB is not limited thereto, and the substrate SUB may be made of various suitable materials.

[0073] The substrate SUB may include a display area AA and a non-display area NA. Figure 1 and Figure 2 In some embodiments, the display area AA may include a plurality of pixel areas PXA in which respective pixels PXL are disposed and / or formed.

[0074] The circuit element layer BPL may be disposed on one surface of the substrate SUB and include at least one conductive layer. For example, the circuit element layer BPL may include a plurality of circuit elements (e.g., at least one transistor and at least one capacitor) constituting the pixel circuit of the pixel PXL and lines for supplying various power supplies and signals for driving the pixel PXL. The circuit element layer BPL may include circuit elements and a plurality of conductive layers for constituting lines connected to the circuit elements. In addition, the circuit element layer BPL may include at least one insulating layer provided between the plurality of conductive layers. In addition, the circuit element layer BPL may include a line portion disposed in the non-display area NA of the substrate SUB to supply corresponding power supplies and corresponding signals to the lines connected to the pixel PXL.

[0075] The light emitting element layer LDL may be disposed on one surface of the circuit element layer BPL. The light emitting element layer LDL may include a plurality of light emitting elements LD connected to circuit elements and / or lines of the circuit element layer BPL through contact holes, etc. In some embodiments, at least one of the plurality of light emitting elements LD may be disposed in each pixel region PXA, such as Figure 4 as shown in .

[0076] Each pixel PXL may include a circuit element provided in the circuit element layer BPL and at least one light emitting element LD provided in a light emitting element layer LDL located on the top of the circuit element layer BPL. The structure of the pixel PXL will be described in detail later.

[0077] The first protective layer PTL1 may be disposed on top of the light emitting element layer LDL to cover the display area AA. The first protective layer PTL1 may include an encapsulation member such as a thin film encapsulation (TFE) or an encapsulation substrate, and may include a protective film or the like in addition to the encapsulation member.

[0078] The first adhesive layer ADL1 is disposed between the first protection layer PTL1 and the window WIN to couple the first protection layer PTL1 and the window WIN to each other. The first adhesive layer ADL1 may include a transparent adhesive such as an optically clear adhesive (OCA), and may include various adhesive materials in addition to the transparent adhesive.

[0079] The window WIN is a protective member disposed at the uppermost portion of the module of the display device 10 including the display panel 110, and may be a substantially transparent transmissive substrate. The window WIN may have a multilayer structure selected from a glass substrate, a plastic film, and a plastic substrate. The window WIN may include a rigid or flexible substrate, and the material constituting the window WIN is not particularly limited.

[0080] In some embodiments of the present disclosure, the display device 10 may further include a polarizer and / or a touch sensor layer (touch electrode layer). For example, the display device 10 may further include a polarizer and / or a touch sensor layer disposed between the first protection layer PTL1 and the window WIN.

[0081] The second protection layer PTL2 may be disposed on the other surface of the substrate SUB. The second protection layer PTL2 may be coupled to the substrate SUB through the second adhesive layer ADL2.

[0082] The second adhesive layer ADL2 may firmly couple (or attach) the substrate SUB and the second protective layer PTL2 to each other. The second adhesive layer ADL2 may include a transparent adhesive such as OCA. The second adhesive layer ADL2 may include a pressure-sensitive adhesive (PSA), and the adhesive material in the PSA functions when pressure is applied to allow the second adhesive layer ADL2 to adhere to the adhesive surface. When the second adhesive layer ADL2 includes the PSA, the second adhesive layer ADL2 may be attached to the adhesive surface by using pressure without a separate heat treatment or UV treatment at room temperature.

[0083] In some embodiments of the present disclosure, the second adhesive layer ADL2 may include a material that absorbs specific light or includes a material that blocks specific light. In one example, the second adhesive layer ADL2 may include an infrared absorbing material that absorbs infrared light with high energy density, or may include an infrared blocking material that blocks infrared light.

[0084] The infrared absorbing material may include, for example, inorganic oxides such as antimony tin oxide (ATO), indium tin oxide (ITO), tungsten oxide, carbon black, and / or metals such as Ag. The inorganic oxide may selectively transmit light in the visible region and absorb infrared light. In addition, the infrared absorbing material may include, for example, an organic dye. The organic dye may be a dye used as a color filter provided in the display panel 110.

[0085] The infrared blocking material can be, for example, selected from borate mixtures, carbonate mixtures, aluminum oxide mixtures, nitrate mixtures, nitrite mixtures, lithium borate, potassium borate, magnesium borate, calcium borate, strontium borate, barium borate, sodium borate, Na 2 B 4 O x , colemanite, lithium carbonate, sodium carbonate, potassium carbonate, calcium carbonate, calcite, CaCO 3, dolomite and / or magnesite. In addition, the infrared blocking material can be at least one selected from one or more dyes, and the one or more dyes are selected from dithiol nickel base, dithiol metal complex compound, cyanine base, squaryl cyanine base, crotonyl cyanine base, diimmonium salt base, amine onium, ammonium base, phthalocyanine dye base, naphthalocyanine base, anthraquinone base, naphthoquinone base, polymer condensation azopyrrole, polymethine base and / or propenyl base.

[0086] When the user's hand (or finger) is placed (or positioned) on the display surface of the display device 10 (e.g., a surface on which an image is displayed), the display device 10 may perform a function of sensing the user's fingerprint through the optical sensor PHS, which may be described later. When external light is introduced into the display device 10 while the display device 10 is sensing the user's fingerprint, a visible region in the external light is blocked by the user's hand, but infrared light may be transmitted through the user's hand and then incident on the optical sensor PHS (e.g., on the optical sensor PHS). The infrared light incident on the optical sensor PHS (e.g., on the optical sensor PHS) serves as noise, and thus the recognition accuracy of the light reflected by the user's hand may be reduced.

[0087] In the above-described embodiment of the present disclosure, when the second adhesive layer ADL2 includes an infrared absorbing material and / or an infrared blocking material, even if infrared light of external light is transmitted through the user's hand, the infrared light is absorbed and / or blocked by the second adhesive layer ADL2. Therefore, the infrared light is not incident on the optical sensor PHS (e.g., on the optical sensor PHS), and thus the recognition accuracy of the user's fingerprint can be improved.

[0088] The second protection layer PTL2 prevents or substantially prevents oxygen and moisture from being introduced from the outside, and may be provided in the form of a single layer or multiple layers. The second protection layer PTL2 may be configured in a film form to further ensure the flexibility of the display panel 110. The second protection layer PTL2 may be coupled to the sensor layer PSL by another adhesive layer including a transparent adhesive such as OCA.

[0089] In some embodiments, a selective light blocking film may be further provided on the bottom of the second protective layer PTL2. The selective light blocking film blocks a specific frequency region (e.g., ultraviolet light introduced into the external light of the display device 10) to prevent or substantially prevent the corresponding light from being incident on the light sensor PHS (e.g., on the light sensor PHS). Although the selective light blocking film is described as being provided on the bottom of the second protective layer PTL2, the embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the selective light blocking film may be provided in any layer of the display device 10 as long as the selective light blocking film is provided on top of the sensor layer PSL. In some embodiments, when a component for blocking ultraviolet light is included in the display panel 110, the selective light blocking film may be omitted.

[0090] The light blocking layer PHL may be disposed between the light emitting element layer LDL and the sensor layer PSL, which may be described later. For example, the light blocking layer PHL may be disposed between the substrate SUB and the circuit element layer BPL, as shown in FIG. Figure 4 In some embodiments of the present disclosure, the light blocking layer PHL may include a plurality of pinholes PIH. The light blocking layer PHL blocks light incident from the outside (eg, some reflected light reflected from a finger), and thus only other reflected light reaches the lower layer through the pinholes PIH.

[0091] The width (or diameter) of the pinhole PIH may be configured such that light satisfying an observation viewing angle that satisfies a set (eg, predetermined) angular range (or referred to as “field of view (FOV) θ”) may be transmitted through each pinhole PIH.

[0092] In addition, the width (or diameter) of the pinhole PIH can be set to about ten times the wavelength of the reflected light (for example, about 4 μm or about 5 μm) so that the diffraction of the light can be prevented or reduced. In addition, the width of the pinhole PIH can be set large enough to prevent or reduce image blur and more clearly sense the shape of the fingerprint. For example, the width of the pinhole PIH can be set to about 20 μm or less. However, the present disclosure is not limited thereto, and the width of the pinhole PIH may vary depending on the wavelength band of the reflected light and / or the module thickness of each layer.

[0093] The distance (or spacing) between adjacent pinholes PIH can be set by considering the distance between the light blocking layer PHL and the sensor layer PSL and the wavelength range of the reflected light. For example, the distance between adjacent pinholes PIH can be set to two or more times the distance between the light blocking layer PHL and the sensor layer PSL that can be described later. The distance between adjacent pinholes PIH can be set to be not less than a value obtained by adding a set (e.g., predetermined) error range to the distance between the light blocking layer PHL and the sensor layer PSL. Therefore, it is possible to prevent or substantially prevent the images observed by the respective light sensors PHS from overlapping each other, and thus image blur can be prevented or reduced.

[0094] The sensor layer PSL may be attached to another surface (e.g., rear surface) of the display panel 110 to overlap at least one area of ​​the display panel 110. The sensor layer PSL may be disposed to overlap the display panel 110 located in the display area AA. The sensor layer PSL may include a plurality of light sensors PHS distributed at a set (e.g., predetermined) resolution and / or a set (e.g., predetermined) distance. The distances between the light sensors PHS may be densely set so that reflected light reflected from an observed object (e.g., a specific area of ​​a finger, such as a fingerprint area) may be incident on at least two adjacent light sensors PHS.

[0095] The light sensor PHS of the sensor layer PSL can receive the reflected light passing through the pinhole PIH and output an electrical signal corresponding to the reflected light as a sensing signal. Based on whether the reflected light is caused by the valley or ridge of the fingerprint formed on the user's finger, the reflected light incident on each light sensor PHS may have different optical properties (e.g., frequency, wavelength, size, etc.). Therefore, the light sensor PHS can output a sensing signal with different electrical characteristics corresponding to the optical properties of the reflected light. The sensing signal output by the light sensor PHS can be converted into an original image. In some embodiments, the sensor image, sensor data and / or sensor image data can be used for fingerprint recognition of the user.

[0096] As described above, the display device 10 according to the present disclosure has a fingerprint sensor including a light emitting element layer LDL, a sensor layer PSL, and a light blocking layer PHL. The light emitting element layer LDL may include a light emitting element LD capable of being used as a light source of a photosensitive fingerprint sensor. The sensor layer PSL may include a light sensor PHS for receiving reflected light emitted from the light emitting element layer LDL and then reflected from an object (e.g., a fingerprint area of ​​a finger) located on top of the display device 10. The light blocking layer PHL may include a pinhole PIH disposed between the light emitting element layer LDL and the sensor layer PSL to allow the reflected light to be selectively transmitted therethrough.

[0097] In some embodiments, the fingerprint sensor may further include an optical opening area formed in the display panel 110, etc. (e.g., formed in the circuit element layer BPL and the light emitting element layer LDL), thereby reducing the loss of reflected light incident on each pinhole PIH within a set (e.g., predetermined) FOV range. In addition, in order to more easily control the FOV, the fingerprint sensor may include a light control layer disposed in the display panel 110 to control the light path. This will be referred to later. Figures 6 to 8 Some embodiments of light management layers are described.

[0098] In some embodiments, the display device 10 uses the light emitting element LD of the pixel PXL as the light source of the fingerprint sensor, but the present disclosure is not limited thereto. For example, the display device according to some embodiments of the present disclosure may have a separate light source for fingerprint sensing.

[0099] The fingerprint sensing method of the display device 10 according to the embodiment described above can be briefly described as follows. During the fingerprint sensing period in which the light sensor PHS is activated, in a state in which the user's finger (e.g., fingerprint area) is in contact with or close to the display area AA, the pixel PXL of the display area AA (particularly, the light emitting element LD provided in the pixel PXL) can emit light. For example, during the fingerprint sensing period, all pixels PXL of the display area AA can emit light simultaneously (e.g., concurrently) or sequentially. In some embodiments, only some of the pixels PXL of the display area AA emit light at a set (e.g., predetermined) distance, or some pixels PXL that only radiate light of a specific color (e.g., short-wavelength light such as blue light) can selectively emit light.

[0100] Some of the light emitted from the pixel PXL may be reflected from the user's finger and then enter the light sensor PHS by passing through the optical opening area and the pinhole PIH formed in each layer of the display device 10. Based on the difference in light amount and / or waveform of the reflected light respectively reflected from the ridges and valleys of the fingerprint, the user's fingerprint shape (fingerprint pattern) may be detected.

[0101] In some embodiments, Figure 4 As shown in , according to the size (e.g., width) of the pinhole PIH and / or FOVθ, only at least some of the light sensors PHS disposed in the sensor layer PSL can receive incident light. In some embodiments, among the sensing signals output by the light sensors PHS, only the sensing signals output by the light sensors PHS that actually receive reflected light can be used as valid sensing signals for fingerprint detection. The sensing signals output by the light sensors PHS that do not receive reflected light blocked by the pinhole PIH may include invalid information corresponding only to black.

[0102] In some embodiments, one or more of the light sensors PHS disposed in the sensor layer PSL may receive reflected light from one pinhole PIH, and other light sensors PHS in the light sensors PHS may receive reflected light from at least two pinholes PIH. In some embodiments, a sensing signal output by a light sensor PHS receiving reflected light from only one pinhole PIH may be used as a valid sensing signal for fingerprint detection. A sensing signal output by a light sensor PHS receiving reflected light from a plurality of pinholes PIH may include inaccurate information due to mutual interference between the received reflected lights.

[0103] Therefore, in Figure 1 and Figure 2 The fingerprint detector 220 shown in can extract a valid area generated based on a valid sensing signal in an original image generated from a sensing signal, and detect a fingerprint based on the extracted valid area. For example, the fingerprint detector 220 can extract a valid area in an original image generated based on a sensing signal, and synthesize the extracted valid area by performing image processing on the valid area. Each valid area can be defined as an area, a partial image, or a portion of sensor data generated based on a sensing signal of a light sensor PHS that receives reflected light through a pinhole PIH in an original image (or sensor data) generated from a sensing signal output by the light sensor PHS.

[0104] Will refer to it later Figures 9 to 17 The fingerprint detection method of the fingerprint detector 220 is described in more detail.

[0105] Figure 5 is a plan view showing a light blocking layer according to some embodiments of the present disclosure.

[0106] refer to Figure 5 , the light blocking layer PHL according to some embodiments of the present disclosure may include a light blocking mask LBM and a plurality of pinholes PIH distributed in the light blocking mask LBM.

[0107] The light blocking mask LBM can be made of a light blocking material and / or a light absorbing material. For example, the light blocking mask LBM can be configured with an opaque metal layer (conductive layer), and the opaque metal layer is locally opened in the area where each pinhole PIH is set. However, the material constituting the light blocking mask LBM is not limited to metal, and the light blocking mask LBM can be made of various materials that can block the transmission of light. For example, the light blocking mask LBM can be made of a black matrix material currently known in the art or any other suitable material.

[0108] The pinholes PIH may be openings distributed in the light blocking mask LBM. The pinholes PIH may be distributed in the light blocking mask LBM in a uniform, substantially uniform, or irregular pattern to have a certain size and distance. In addition, the pinholes PIH may be arranged to have a resolution lower than the resolution of the light sensor PHS arranged in the sensor layer PSL. However, the present disclosure is not limited thereto, and the size, number, resolution, and / or arrangement structure of the pinholes PIH may be variously modified in an appropriate manner.

[0109] Despite Figure 5 The pinhole PIH has a rectangular shape, but the embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the pinhole PIH may have various shapes, such as a rectangular shape, a circular shape, an elliptical shape, and a polygonal shape.

[0110] exist Figure 4 In the display device 10 shown in FIG. 1 , the light blocking layer PHL may be provided between the light emitting element layer LDL in which the light emitting element LD is arranged and the sensor layer PSL in which the light sensor PHS is arranged. The light blocking layer PHL may constitute an optical system for selectively allowing only some light to be transmitted through the optical system and blocking other light.

[0111] The light blocking layer PHL and the light sensor PHS as described above may constitute a fingerprint sensor together. In addition, the light blocking layer PHL may be formed integrally with the circuit element layer BPL of the display panel 110. Therefore, the module thickness of the photosensitive fingerprint sensor and the display device having the photosensitive fingerprint sensor may be reduced or minimized.

[0112] Figure 6 is a schematic cross-sectional view of a display panel according to some embodiments of the present disclosure. Figure 7 is a schematic cross-sectional view of a display panel according to some embodiments of the present disclosure. Figure 8 is a schematic cross-sectional view of a display panel according to some embodiments of the present disclosure. Figures 6 to 8 In the description, detailed description of components similar or identical to at least one of the embodiments described above may be omitted.

[0113] refer to Figure 6 , the circuit element layer BPL may include a light transmission hole array layer LTHL provided or disposed in the sensing area SA. For example, the light transmission hole array layer LTHL may include a plurality of light transmission holes LTH distributed in the circuit element layer BPL. In some embodiments, a light transmission hole array layer LTHL may be provided instead of the light blocking layer PHL. That is, the light transmission holes LTH may be used as pinholes PIH, respectively.

[0114] like Figure 6As shown in , when the pinhole PIH is configured using a plurality of light-transmitting holes LTH distributed in the circuit element layer BPL without separately providing a light-blocking layer PHL, a separate mask process for forming the light-blocking layer PHL can be omitted. Figure 6 The display device of some embodiments shown in can prevent or reduce the thickness increase caused when the light blocking layer PHL is provided separately. In addition, the manufacturing cost can be reduced, and the process efficiency can be improved.

[0115] refer to Figure 7 and Figure 8 , the circuit element layer BPL may include a light transmission hole array layer LTHL including a plurality of light transmission holes LTH. In some embodiments, a light blocking layer PHL including a plurality of pinholes PIH may be disposed between the substrate SUB and the circuit element layer BPL. The light transmission holes LTH and the pinholes PIH may be arranged so that at least some of the light transmission holes LTH and the pinholes PIH overlap each other.

[0116] In some embodiments of the present disclosure, the light-transmitting hole LTH and the pinhole PIH may have sizes that are equal, substantially equal, or different from each other. For example, the light-transmitting hole LTH may have a width (or diameter) that is smaller than the width (or diameter) of the pinhole PIH, such as Figure 7 For example, the light transmission hole LTH and the pinhole PIH have a width (or diameter) ranging from 5 μm to 20 μm, and the width (or diameter) of the light transmission hole LTH may be smaller than the width (or diameter) of the pinhole PIH.

[0117] In some embodiments, the light-transmitting hole LTH has a size smaller than that of the pinhole PIH. Therefore, the light-transmitting hole array layer LTHL can be used as a light control layer LBL for controlling the light path (e.g., limiting the FOV of the reflected light to a set (e.g., predetermined) angle range), and the light blocking layer PHL can perform a light blocking function.

[0118] and Figure 7 In contrast, in some embodiments, the light transmitting hole LTH may have a width (or diameter) greater than the width (or diameter) of the pinhole PIH, such as Figure 8 In some embodiments, the light transmitting hole array layer LTHL may perform a light blocking function, and the light blocking layer PHL may serve as a light controlling layer LBL for controlling a light path.

[0119] Fig. 9 is a block diagram illustrating a configuration of a fingerprint detector according to some embodiments of the present disclosure. Figures 10 to 12 is a view illustrating a method of generating a white calibration image according to some embodiments of the present disclosure. Figures 13 to 17 is a view illustrating a raw image processing method according to some embodiments of the present disclosure.

[0120] refer to Fig. 9 According to some embodiments of the present disclosure, the fingerprint detector 220 may include a white calibration image memory 221 (or calibration data memory), an image processor 222, and a white calibrator 223 (or calibrator). Fig. 9 The components are independent of each other, but the embodiments of the present disclosure are not limited thereto. In some embodiments, at least some of the white calibration image memory 221, the image processor 222, and the white calibrator 223 may be integrated into one component or separated into more than one component. In some embodiments, the white calibration image memory 221 may be provided separately outside the fingerprint detector 220 (e.g., in Figure 1 and Figure 2 A storage device of the panel driver 210 shown in FIG.

[0121] The white calibration image memory 221 may store a white calibration image (or calibration data) for white calibration. White calibration may be defined as removing the white calibration image due to the light sensor PHS (see Figure 4 ), pinhole PIH (see Figure 4 ), optical opening area, etc., thereby ensuring the uniformity of the optical sensor PHS located in the sensor layer PSL (see Figure 4 Before the display device 10 having the fingerprint sensor 220 is initially driven (eg, before the product is shipped), the white calibration image may be stored in the white calibration image memory 221.

[0122] In some embodiments, the white calibration image may be generated using the following method. First, based on a sensing signal output from the light sensor PHS by sensing light of the color (eg, skin color) of the object to be detected located on the display panel 110, a white calibration image may be generated as follows: Fig.10 The original white calibration image shown in (ie, calibration data about all the photosensors PHS) may be converted so as to constitute one pixel in the original white calibration image (or constitute a value corresponding to the one pixel).

[0123] In some embodiments, in a state where an object having skin color or an object having a specific reflectivity (e.g., a reflectivity of about 70%) is disposed on the display panel 110, an original white calibration image may be generated by converting a sensing signal output from the light sensor PHS into image data. In some embodiments, in a state where light of skin color is irradiated onto the display panel 110, an original white calibration image may be generated by converting a sensing signal output from the light sensor PHS into image data. The original white calibration image may include a light signal generated by the light sensor PHS (see Figure 4 ) etc. (for example, noise related to the color of the object to be detected).

[0124] As reference Figure 4 As described, some of the light sensors PHS that substantially receive only reflected light or receive reflected light from one pinhole PIH among the light sensors PHS can output effective sensing signals. In some embodiments, the original white calibration image can be processed so that the effective area EA generated based on the effective sensing signal is preserved.

[0125] Specifically, the effective area EA can be extracted from the original white calibration image, as Fig.11 As shown in Fig.11 In the example shown in Fig.10 The effective area EA may represent a region, a partial image, or a portion of sensor data generated based on a sensing signal of the photosensor PHS receiving reflected light through one pinhole PIH in the original white calibration image.

[0126] The extracted effective areas EA may be synthesized to generate a final white calibration image. For example, the extracted effective areas EA may be spliced ​​(or stitched) to be combined into one image, such as Fig.12 as shown in .

[0127] In some embodiments, when synthesizing the effective area EA, image interpolation may be applied to pixels included in the spliced ​​edge area. For example, image interpolation may be performed by calculating the average value of image data of the corresponding pixel and the adjacent pixel. In some embodiments, image interpolation may be performed using the original white calibration image of the invalid area instead of the effective area EA. Image interpolation may be performed in various methods known in the art and is not limited to a specific method.

[0128] Because in Fig.12 The final white calibration image generated according to some embodiments of the present disclosure shown in FIG. 1 is generated using only the extracted effective area EA, so the final white calibration image has a larger Fig.10The capacity of the original white calibration image shown in the figure is small. Therefore, the fingerprint sensor according to the present disclosure can reduce the storage space required to store the white calibration image. In addition, since the final white calibration image generated according to the present disclosure has a small capacity, when white calibration is performed using the final white calibration image, the loading time of the white calibration image can be reduced.

[0129] The image processor 222 may generate a raw image (or sensor data) based on a sensing signal received from the outside (eg, a light sensor PHS), and perform image processing on the raw image. Figure 4 As described, during the fingerprint sensing period, the pixel PXL of the display area AA (or the sensing area SA) emits light, some of the light is reflected from the user's finger, and the reflected light is incident into the light sensor PHS through the pinhole PIH. A sensing signal from the light sensor PHS receiving the reflected light can be provided to the image processor 222.

[0130] Specifically, the image processor 222 may convert the sensing signal received from the light sensor PHS into a raw image, such as Fig.13 As shown in . A sensing signal received from a photosensor PHS may be converted to constitute a pixel located in an original image.

[0131] In some embodiments, the image processor 222 may be externally (e.g., Figure 1 The coordinate information may include information about the location of the contact of the object to be sensed (e.g., Figure 1 When the coordinate information is received, the image processor 222 can extract the touch area TA corresponding to the corresponding coordinates in the original image, such as Fig.14 As shown in , and an operation that can be described later is performed only on the extracted touch area TA.

[0132] In some embodiments, when the sensing area is limited to a specific area located on the display panel 110, such as Figure 1 As shown in , the image processor 222 may not receive coordinate information separately. Therefore, the image processor 222 may perform an operation that may be described later on the entire original image.

[0133] In the following embodiment, a case is described where the image processor 222 receives coordinate information and performs image processing only on the touch area TA. However, even when the image processor 222 performs image processing on the entire original image without receiving coordinate information, the following embodiment can be applied in the same manner.

[0134] The image processor 222 may extract the effective area EA from the original image (ie, the original image corresponding to the touch area TA), such as Fig.15 As shown in Fig.15 In the example shown in Fig.14 Only some of the effective areas EA extracted from the original image are shown in FIG. The effective area EA may represent an area generated based on a sensing signal of the photosensor PHS that receives reflected light through one pinhole PIH.

[0135] In some embodiments, the image processor 222 may perform image processing on the extracted effective area EA.

[0136] For example, the image processor 222 may perform smoothing on the active area EA, such as Fig.16 As shown in . For example, the image processor 222 can increase the brightness separation about the effective area EA, and remove noise, etc. Smoothing can be performed by a histogram analysis involving each pixel in the original image. For example, a median filtering method can be used to perform smoothing. Various suitable algorithms known in the art can be used to perform smoothing, and the method for performing smoothing is not particularly limited.

[0137] In some embodiments, the image processor 222 may perform binarization and thinning on the extracted effective area EA. For example, the image processor 222 may convert multiple grayscale levels or grayscale levels (e.g., at least one corresponding grayscale level or grayscale level among 256 grayscale levels or grayscale levels) of the effective area EA into values ​​corresponding to 0 (black) or 1 (white). Then, the ridges constituting the fingerprint may be clearly defined as black, and the valleys constituting the fingerprint may be clearly defined as white. In addition, the image processor 222 may generate a line image in which the width of the ridge is one pixel from the binarized image. Binarization and thinning are performed to improve the accuracy of fingerprint detection, and may be omitted when binarization and thinning are not required.

[0138] In some embodiments, when at least one of the image processing operations described above is omitted or desired, a greater number of image processing operations may be performed. For example, when the original image is a sufficiently satisfactory image with a small amount of noise, smoothing may not be performed.

[0139] The image processor 222 can generate an image by synthesizing the effective area EA that has been image processed as described above. For example, by splicing the extracted effective area EA, the image processor 222 can generate a synthesized image, synthesized data, or synthesized image data, such as Fig.17 as shown in .

[0140] The white calibrator 223 may perform white calibration on the composite image generated by the image processor 222. Specifically, the white calibrator 223 may load the white calibration image from the white calibration image memory 221. The white calibrator 223 may perform white calibration on the composite image based on the white calibration image. For example, the white calibrator 223 may differencing (or subtracting) the white calibration image from the composite image. Since the white calibration image contains noise as described above, the noise may be removed from the composite image by image difference.

[0141] In some embodiments of the present disclosure, the white calibration image has a reduced (or compressed) form, size or volume compared to the original white calibration image as described above. Therefore, after image synthesis is performed by the image processor, the white calibration according to the present disclosure can be applied to the synthesized image.

[0142] The final image calibrated by the white calibrator 223 (i.e., calibrated sensor data) can be used to detect fingerprints. For example, in the case of fingerprint registration, the fingerprint detector 220 can store the final image and information related to the final image in the fingerprint detector 220 or in a separate storage space provided externally. When fingerprint detection is subsequently performed, the stored final image can be used as reference data.

[0143] In the case of fingerprint authentication, the fingerprint detector 220 may acquire the final image from the outside, or determine whether the fingerprint authentication is successful by comparing the final image with reference data stored in the fingerprint detector 220 .

[0144] Fig.18 is a flow chart illustrating a fingerprint sensing method of a fingerprint sensor according to some embodiments of the present disclosure. In particular, Fig.18 It is shown in Figure 1 Flow chart of the fingerprint sensing method of the fingerprint detector shown in .

[0145] refer to Figures 9 to 18 , the fingerprint detector 220 may store a white calibration image (or calibration image) (1801). The white calibration image may be generated by extracting a valid area (or partial data having a valid value) from an original white calibration image (ie, calibration data about all light sensors PHS) and synthesizing the extracted valid area.

[0146] Method and reference for generating white calibration images Figures 9 to 12 The described methods are the same, and thus a detailed description thereof may be omitted.

[0147] In some embodiments of the present disclosure, the generation and storage of the white calibration image may be performed at least once before the initial driving of the display device 10 (for example, before the product is shipped). However, the embodiments of the present disclosure are not limited thereto, and the generation and storage of the white calibration image may be performed after the initial driving of the display device 10.

[0148] In some embodiments, the white calibration image may be generated by another external device to be transmitted to the fingerprint detector 220. Therefore, the step of receiving the white calibration image from the outside may be performed before the step of storing the white calibration image.

[0149] The fingerprint detector 220 may receive a sensing signal from the light sensor PHS (1802). When a contact of an object to be sensed occurs according to a set (eg, predetermined) period or on the display panel 110, the fingerprint detector 220 may receive a sensing signal from the light sensor PHS. However, the present disclosure is not limited thereto.

[0150] In some embodiments, the fingerprint detector 220 may receive coordinate information from the panel driver 210, etc. The coordinate information may include information about the location where contact (e.g., touch of a finger) of the object to be sensed occurs. When the coordinate information is received, the fingerprint detector 220 may perform an operation that may be described later on a sensing signal received from the optical sensor PHS at a location corresponding to the coordinate information among sensing signals received from the optical sensor PHS.

[0151] The fingerprint detector 220 may generate a raw image (or sensor data) from the received sensing signal (1803). For example, the fingerprint detector 220 may generate a raw image by converting a sensing signal received from a light sensor PHS into a pixel image.

[0152] The fingerprint detector 220 may extract a valid area from the generated original image (1804). The valid area may be an area generated based on a sensing signal of the photosensor PHS that receives reflected light through one pinhole.

[0153] The fingerprint detector 220 may perform image processing on the extracted valid area (1805). The image processing may include, for example, at least one of smoothing, binarization, and thinning. However, the embodiments of the present disclosure are not limited thereto, and according to the embodiments of the present disclosure, a greater or lesser number of image processing techniques may be applied. In addition, in some embodiments, the step of performing image processing may be omitted.

[0154] The fingerprint detector 220 may synthesize the image-processed valid area (1806). For example, the fingerprint detector 220 may generate a synthesized image (or synthesized data) by splicing the image-processed valid area. In some embodiments, the synthesis of the valid area may be performed before the image processing is performed on the valid area.

[0155] The fingerprint detector 220 may perform white calibration on the composite image (1807). Specifically, the fingerprint detector 220 may load a pre-stored white calibration image. The fingerprint detector 220 may remove noise from the composite image by differentiating the loaded white calibration image from the composite image.

[0156] The fingerprint detector 220 may detect a fingerprint based on the final image on which the white calibration is performed (1808). The fingerprint detector 220 may store information about the extracted fingerprint, or further perform a desired operation such as authentication by comparing the information about the extracted fingerprint with information about pre-stored fingerprints.

[0157] In the fingerprint sensing method, fingerprint sensor, and display device including the fingerprint sensor according to the present disclosure, only the effective area (i.e., the calibration value corresponding to the effectively operated light sensor) in the original white calibration image (i.e., the calibration image of all light sensors) is extracted and synthesized, and the synthesized image is stored as the final white calibration image. Therefore, the storage space of the white calibration image can be minimized or reduced, and the loading time of the white calibration image can be reduced.

[0158] In addition, in the fingerprint sensing method, fingerprint sensor, and display device including the fingerprint sensor according to the present disclosure, an effective area is extracted and synthesized from an original image (i.e., sensing data) acquired by the optical sensor, and white calibration is performed on the synthesized image, so that the time required to perform white calibration on the original image acquired by the optical sensor can be reduced.

[0159] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, the first element, component, region, layer or part discussed below may be referred to as a second element, component, region, layer or part without departing from the spirit and scope of the present inventive concept.

[0160] As used herein, a “plan view” may refer to a view viewed from the top or from a direction perpendicular to a display area (or display plane) of a display device.

[0161] For ease of explanation, spatially relative terms such as "under", "beneath", "below", "below", "on", "above", and "behind" may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. It will be understood that the spatially relative terms are intended to cover different orientations of the device in use or operation other than the orientation depicted in the figures. For example, if the device in the figure is turned over, the element described as "under" or "below" or "below" other elements or features will then be oriented "above" the other elements or features. Thus, the exemplary terms "under" or "below" can cover both "above" and "below" orientations. The device may be otherwise oriented (e.g., rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly. In addition, it will also be understood that when a layer is referred to as "between" two layers, it can be the only layer between the two layers, or there may also be one or more intermediate layers.

[0162] The terms used in this article are for the purpose of describing specific embodiments, and are not intended to limit the inventive concept. As used in this article, the singular forms "one", "an" and "said" are also intended to include plural forms, unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms "including" and / or "just including" specify the existence of stated features, wholes, steps, operations, elements and / or components, but do not exclude the existence or increase of one or more other features, wholes, steps, operations, elements, components and / or their groups. As used in this article, the term "and / or" includes any and all combinations of one or more associated listed items. When located after the element list, statements such as "at least one of..." modify the entire element list, and are not a single element of the modified list. In addition, when describing the embodiment of the inventive concept, the use of "may" represents "one or more embodiments of the inventive concept". In addition, the term "exemplary" is intended to represent an example or description.

[0163] It will be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to,” or “adjacent to” another element or layer, it can be directly on, directly connected to, coupled to, or adjacent to the other element or layer, or one or more intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on,” “directly connected to,” “directly coupled to,” or “immediately adjacent to” another element or layer, there are no intervening elements or layers.

[0164] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and interpreted in a general and descriptive sense only, and not for purposes of limitation. In some cases, as will be apparent to one of ordinary skill in the art as of the time of filing this application, features, characteristics, and / or elements described in conjunction with a specific embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise specifically noted. Therefore, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the present disclosure as set forth in the appended claims and their equivalents.

Claims

1. A fingerprint sensor, wherein: The fingerprint sensor comprises: substrate; a light blocking layer on the first surface of the substrate, the light blocking layer comprising openings in the light blocking mask; a sensor layer on the second surface of the substrate, the sensor layer comprising a light sensor; and a fingerprint detector configured to generate an original image based on a sensing signal from the light sensor, perform calibration on the original image by using a calibration image, and detect a fingerprint based on the calibrated image, The calibration image is generated by synthesizing a valid area extracted from an original calibration image corresponding to the original image.

2. The fingerprint sensor according to claim 1, wherein: The light blocking layer is configured to transmit first light incident to the light blocking layer to the sensor layer through the opening and to block second light.

3. The fingerprint sensor according to claim 1, wherein: A first light sensor of the light sensor is configured to receive light through one opening, and a second light sensor of the light sensor is configured not to receive light or to receive light through two or more openings.

4. The fingerprint sensor according to claim 1, wherein: The effective area is generated based on a sensing signal from a first light sensor among the light sensors configured to receive light through an opening.

5. The fingerprint sensor according to claim 4, wherein: The original calibration image is generated based on a sensing signal output from the light sensor in response to skin-colored light.

6. The fingerprint sensor according to claim 5, wherein: The calibration image is generated by extracting the valid area in the original calibration image and stitching the valid area.

7. The fingerprint sensor according to claim 6, wherein: The calibration image has a smaller capacity than a capacity of the original calibration image.

8. The fingerprint sensor according to claim 6, wherein: The fingerprint detector is configured to extract the valid areas in the original image, generate a composite image by stitching the extracted valid areas, and perform calibration on the composite image by using the calibration image.

9. The fingerprint sensor according to claim 8, wherein: The fingerprint detector is further configured to perform the calibration by loading the calibration image and subtracting the calibration image from the composite image.

10. The fingerprint sensor according to claim 8, wherein: The fingerprint detector is further configured to perform at least one image processing of smoothing, binarization, and thinning on the effective area or the composite image.

Images