WO2022030615A1 - Optical fingerprint sensor - Google Patents

Optical fingerprint sensor Download PDF

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Publication number
WO2022030615A1
WO2022030615A1 PCT/JP2021/029272 JP2021029272W WO2022030615A1 WO 2022030615 A1 WO2022030615 A1 WO 2022030615A1 JP 2021029272 W JP2021029272 W JP 2021029272W WO 2022030615 A1 WO2022030615 A1 WO 2022030615A1
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WIPO (PCT)
Prior art keywords
light
layer
hole
shielding layer
opening
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PCT/JP2021/029272
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French (fr)
Japanese (ja)
Inventor
英聡 萩原
誠 坂川
Original Assignee
凸版印刷株式会社
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Application filed by 凸版印刷株式会社 filed Critical 凸版印刷株式会社
Priority to CN202180057728.6A priority Critical patent/CN116134626A/en
Publication of WO2022030615A1 publication Critical patent/WO2022030615A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/117—Identification of persons
    • A61B5/1171—Identification of persons based on the shapes or appearances of their bodies or parts thereof
    • A61B5/1172—Identification of persons based on the shapes or appearances of their bodies or parts thereof using fingerprinting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device

Definitions

  • the present invention relates to an optical fingerprint sensor that optically recognizes a fingerprint.
  • Mobile terminal devices using touch panels such as smartphones are becoming widespread.
  • an operation of personal authentication of a user may be performed in order to release a lock that protects security.
  • the biometric authentication sensor is adopted as a method for reliably authenticating the user himself / herself.
  • Patent Document 1 describes a biometric authentication sensor that recognizes a finger vein.
  • the biometric authentication sensor includes, for example, a light receiving layer having a plurality of light receiving elements. Since the light incident on the light receiving element of the light receiving layer also travels in the oblique direction, it also enters the adjacent light receiving element and becomes noise called crosstalk.
  • a light blocking layer that blocks light may be used in the upper layer of the light receiving layer.
  • a plurality of open holes are formed above the plurality of light-receiving elements at positions corresponding to the plurality of light-receiving elements.
  • two light-shielding layers in which a plurality of holes are formed are provided on the upper layer of the light-receiving layer.
  • a lens layer having a plurality of lenses is arranged at positions corresponding to a plurality of holes to limit the traveling direction of incident light and reduce crosstalk incident on a plurality of light receiving elements. ing.
  • an optical fingerprint sensor that recognizes a fingerprint is being adopted as a biometric authentication provided on the lower layer on the opposite side of the touch panel of the mobile terminal.
  • Mobile terminals are required to be thinner.
  • an optical fingerprint sensor is provided under the touch panel, it is desirable that the thickness of the sensor be as thin as possible.
  • a two-layer light-shielding layer is provided and a lens layer is provided on an upper layer of the two-layer lens layer. As the device configuration becomes complicated, the thickness of the sensor increases.
  • the present invention has been made in view of the above circumstances, and provides an optical fingerprint sensor capable of reducing crosstalk of incident light while simplifying the configuration.
  • An optical fingerprint sensor provided on a surface opposite to the visual recognition side of an organic EL display, the light receiving layer having a plurality of light receiving elements arranged two-dimensionally on a substrate, and the light receiving layer on the visual viewing side.
  • a transparent layer formed and a light-shielding layer formed on a surface of the transparent layer opposite to the light-receiving layer are provided.
  • first opening having a first diameter on the outermost surface on the viewing side
  • second opening having a second diameter on the outermost surface on the transparent layer side
  • the light shielding there is a first opening having a first diameter on the outermost surface on the viewing side
  • a second opening having a second diameter on the outermost surface on the transparent layer side
  • the film thickness of the layer is t 1
  • the film thickness of the transparent layer is t 2
  • the second diameter is d 1
  • the distance between adjacent light receiving elements is d 2
  • difference between the second diameter and the first diameter When 1/2 of the above is x, it may be configured to satisfy the conditional expression t 1 / (d 1 ⁇ x)> t 2 / d 2 .
  • the slope connecting the end of the first opening and the end of the second opening may be formed linearly in the cross-sectional shape of the light-shielding layer in the film thickness direction. ..
  • the slope connecting the end of the first opening and the end of the second opening in the cross-sectional shape of the light-shielding layer in the film thickness direction is the center of the diameter in the radial direction of the hole. It may be formed so as to be convex toward.
  • the slope connecting the end of the first opening and the end of the second opening in the cross-sectional shape of the light-shielding layer in the film thickness direction is the center of the diameter in the radial direction of the hole. It may be formed so as to be concave toward.
  • crosstalk of incident light can be reduced while simplifying the configuration.
  • the optical fingerprint sensor 1 is provided on the surface side opposite to the visual recognition side of the display C provided in a mobile terminal such as a smartphone S, for example.
  • the display C is an organic EL display that displays a display image by self-luminous pixels, and has a known configuration.
  • the optical fingerprint sensor 1 detects a fingerprint pattern by detecting the intensity of light reflected from the fingerprint Y illuminated by the light source (pixel) of the display C. The user touches the area displayed on the display C with a fingertip to cause the optical fingerprint sensor 1 to recognize the fingerprint.
  • the optical fingerprint sensor 1 has a light receiving layer 2 for detecting the intensity of light and a light shielding layer 10 provided on an upper layer on the surface side of the light receiving layer 2 on the light receiving side. Be prepared.
  • the light receiving layer 2 has a plurality of light receiving elements 3.
  • the light receiving element 3 receives light and detects the intensity thereof.
  • the light receiving element 3 outputs a voltage proportional to the intensity of the received light.
  • the plurality of light receiving elements 3 are arranged in a two-dimensional matrix on the surface of the base material M on the light receiving side.
  • the distance between the adjacent light receiving elements 3 is arranged, for example, at the distance between the pixels of the display C.
  • the light receiving element 3 is formed in a circular shape, for example, when the surface of the display C is viewed from the viewing side along the normal direction.
  • the light receiving element 3 may be formed in a shape other than a circle.
  • the base material M is, for example, a silicon wafer.
  • the plurality of light receiving elements 3 receive the light reflected from the fingerprint, detect the intensity of the reflected light generated by the unevenness of the fingerprint, and detect the fingerprint pattern.
  • a transparent layer T is provided on the upper layer of the light receiving layer 2 (that is, the surface side on the light receiving side).
  • the transparent layer T is an optical filter that transmits through the visible light region.
  • the transparent layer T is formed, for example, to have a thickness in the range of 4 ⁇ m to 5 ⁇ m.
  • the transparent layer T is laminated with, for example, a plurality of transparent optical filter layers having different thicknesses, refractive indexes, and the like. The thickness and refractive index of each layer are adjusted so as to offset and shield visible light in a set wavelength range by interference. That is, in the transparent layer T, the light incident from the light receiving side of the transparent layer T is gradually blocked from the light in each wavelength range in each layer of the transparent layer T, and the visible light region is removed in the desired infrared wavelength range. It is preferable that the light reaches the light receiving layer 2 on the surface side opposite to the surface on the light receiving side.
  • a light-shielding layer 10 that blocks light is formed on the upper surface of the transparent layer T (that is, the surface on the light-receiving side).
  • the light-shielding layer 10 is formed to have a thickness of, for example, about 1.5 ⁇ m.
  • a plurality of holes 11 are formed in the light-shielding layer 10. The holes 11 are arranged in a two-dimensional matrix at positions corresponding to the light receiving element 3 when viewed in a plan view from the viewing side.
  • the hole 11 has, for example, a diameter about three times the diameter of the light receiving element 3.
  • the plurality of holes 11 are described so as to be arranged concentrically with the plurality of light receiving elements 3, for example.
  • the arrangement relationship of the plurality of holes 11 is not limited to this, and the light receiving element 3 may be arranged at the time of the holes 11. However, even in this case, the pitches of the plurality of light receiving elements 3 and the plurality of holes 11 are arithmetic progressions.
  • the plurality of holes 11 are provided to improve the reading accuracy of the optical fingerprint sensor 1, and are formed as a diaphragm so that light does not easily enter the light receiving element 3 from the adjacent holes 11 from an oblique direction.
  • the cross sections of the ends of the plurality of holes 11 are formed in an inverted tapered shape so that the diameter increases toward the transparent layer T direction.
  • the reverse taper shape means, for example, a shape in which the diameter becomes the same or more as the opening of the hole 11 toward the light receiving layer 2 side. That is, the hole 11 is formed in an inverted dish-shaped cross section having a linear inclined surface. Further, the reverse taper shape can be defined as a state in which the diameter of the surface of the hole 11 in contact with the transparent layer T is larger than the diameter of the surface of the hole 11 in contact with the layer opposite to the transparent layer T.
  • the transparent resin layer J is applied to the surface of the light-shielding layer 10 having the holes 11 opposite to the transparent layer T, and penetrates into the plurality of holes 11.
  • the transparent resin layer J is formed so as to coat the light-shielding layer 10 after curing.
  • the transparent resin layer J is formed by using, for example, a photocurable resin.
  • the hole 11 prevents obliquely incident light from incident on the light receiving element 3 arranged at a position corresponding to the hole adjacent to the hole 11.
  • a first opening 11A having a first diameter is formed on the surface on the transparent resin layer J side (that is, the outermost surface on the visual recognition side), and the surface on the light receiving element 3 side (that is, the outermost surface on the transparent layer T side).
  • a second opening 11B having a second diameter is formed therein. The second diameter of the second opening 11B is formed to have a size equal to or larger than the first diameter of the first opening 11A.
  • the film thickness of the light-shielding layer 10 is t 1
  • the film thickness of the transparent layer T is t 2
  • the second diameter of the second opening 11B is d 1
  • the adjacent light receiving element is x.
  • the distance between 3 is d 2
  • the distance between the eaves having the inverted taper shape that is, 1/2 of the difference between the second diameter of the second opening 11B and the first diameter of the first opening 11A
  • the following conditional expression (1) is satisfied.
  • the left side is the ratio of the base to the opposite side of a right triangle whose hypotenuse is the hypotenuse connecting the end of the first opening 11A and the end of the second opening 11B facing in the radial direction of the hole 11.
  • x ⁇ 0.
  • the right side is the ratio of the base to the opposite side of a right triangle having the distance between adjacent light receiving elements 3 as the base and the thickness of the transparent layer T as the opposite side.
  • the light-shielding layer 10 is adjacent to the light-shielding layer 10 when the tapered shape of the hole 11 is designed so as to satisfy the conditional expression (1) and the incident light having the maximum value of the incident angle ⁇ in the diagonal direction in the hole 11 is incident on the hole 11. It prevents light from being incident on the light receiving element 3 and reduces crosstalk.
  • the condition shown in the conditional expression (1) does not necessarily completely prevent the incident light in the oblique direction from being incident on the light receiving element 3 adjacent to the hole 11. However, by applying the conditional expression (1) at the time of designing the hole 11, it is verified whether or not the crosstalk is reduced.
  • the cross section of the hole is formed into a reverse taper shape of the hole 11 and a forward taper shape in which the state of the opening is reversed.
  • the diameter of the opening on the transparent layer T side is larger than the diameter of the opening on the transparent resin layer J side.
  • the incident light in the oblique direction is incident on the light receiving element 3 from the adjacent hole 11, and crosstalk is likely to occur.
  • the light-shielding layer 10 has an improved S / N ratio and significantly reduced noise (crosstalk) as compared with the light-shielding layer 10H having holes formed in a forward taper shape. ..
  • FIG. 5 shows the calculation results of Examples and Comparative Examples in which the size d 1 of the second diameter of the second opening 11B of the hole 11 of the light-shielding layer 10 is fixed and the other dimensions are changed. .. As shown in the calculation result, when the second diameter of the second opening 11B is equal to or larger than the first diameter of the first opening 11A in the hole 11, the conditional expression (1) is satisfied and the crosstalk is reduced.
  • the light-shielding layer 10 is formed of a photocurable resin mixed with a black light-shielding substance.
  • the photocurable resin is a photosensitive material that is transparent and cures when irradiated with ultraviolet rays.
  • the light-shielding layer 10 is a photo-curing resin mixed with a black pigment which is a light-shielding substance before curing. This photocurable resin is applied to the surface of the transparent layer T on the light receiving side.
  • a photomask covering a plurality of holes 11 is applied to the surface side of the photocurable resin mixed with the applied black pigment on the light receiving side to perform patterning processing, and ultraviolet rays are applied from the light receiving side (that is, the surface opposite to the transparent layer T). Irradiate.
  • the photocurable resin in the portion other than the plurality of holes 11 is cured.
  • the uncured photocurable resin in the plurality of holes 11 is removed, the light-shielding layer 10 is formed.
  • the light-shielding layer 10 it is necessary for the light-shielding layer 10 to allow ultraviolet rays to reach the contact surface with the transparent layer T in order to prevent peeling from the transparent layer T after curing while ensuring the light-shielding property. .. Therefore, in the present embodiment, it is preferable that the light-shielding layer 10 slightly transmits light having a wavelength in the ultraviolet region while blocking light having a wavelength in the visible light region including an infrared region.
  • the light-shielding layer 10 has a light transmittance in the wavelength range of 400 nm to 700 nm of 1% or less, and a light transmittance in the wavelength range of 360 nm to 400 nm is 0. It is preferably 05% or more.
  • the light-shielding layer 10 contains, for example, a black pigment containing at least one of titanium nitride, titanium oxynitride, titanium oxide, and titanium carbide as a main component.
  • the transmittance of the light-shielding layer 10 changes depending on the film thickness. The transmittance decreases as the film thickness increases.
  • the light-shielding layer 10 having a reverse-tapered shape formed of the above-mentioned material does not interfere with the transmission of ultraviolet rays (for example, wavelength 365 nm) used for photo-curing, and is therefore irradiated with ultraviolet rays during curing.
  • Ultraviolet rays reach the boundary between the transparent layer T and the transparent layer T, and are formed as a cured film on the surface side of the transparent layer T on the light receiving side.
  • the taper angle of the tapered shape of the hole 11 is adjusted by adjusting the balance between the film thickness, the exposure time, and the curing time. As described above, the taper angle is determined by the size of the distance x of the eaves portion of the hole 11.
  • the amount of ultraviolet rays reaching the transparent layer T in the light-shielding layer 10 with time decreases, and the hole 11 can be formed into a reverse tapered shape having a large distance x.
  • the exposure time of ultraviolet rays is increased when the light-shielding layer 10 is cured, the amount of ultraviolet rays reaching the transparent layer T in the light-shielding layer 10 with time increases, and the hole 11 can be formed into a reverse tapered shape having a small distance x.
  • the cured light-shielding layer 10 blocks light having a wavelength in the visible light region including an infrared region, and transmits light to the transparent layer T side only from a plurality of holes 11 portions.
  • the holes 11 are formed in a forward-tapered shape by adjusting the exposure time of ultraviolet rays and the like.
  • the light-shielding layer 10 may be formed of a black pigment containing carbon black. In such a light-shielding layer, ultraviolet rays are less likely to reach the transparent layer T side than the above-mentioned materials.
  • the light-shielding layer 10 is formed by using a material containing a black pigment containing carbon black, if the exposure time is sufficiently adjusted so that the ultraviolet rays reach the transparent layer T side, a forward taper shape is formed.
  • the light-shielding layer 10 having the holes 11 is formed.
  • the reverse-tapered light-shielding layer 10 is formed by using a black pigment containing carbon black, peeling occurs at the boundary between the object and the object when the light-shielding layer 10 is formed so as to cover the object. May occur. Therefore, as described above, the light-shielding layer 10 formed of a material that slightly transmits light having a wavelength in the ultraviolet region prevents peeling at the boundary with the transparent layer T. Therefore, it is desirable that the light-shielding layer 10 having a reverse taper shape is formed by using the above-mentioned material.
  • Modification 1 modification 1 of the light-shielding layer 10 will be described.
  • the condition that the slope is formed into a linear inverted tapered shape in the cross section of the hole 11 is shown so as to prevent crosstalk.
  • the reverse taper shape of the ideal hole 11 of the light-shielding layer 10 of the above embodiment is not always formed, and it may be deformed and formed.
  • an example in which the light-shielding layer 10 is formed into a deformed reverse taper shape while having the same effect as the light-shielding layer 10 is shown.
  • the same name and reference numeral will be used for the same configuration as the above embodiment, and duplicate description will be omitted as appropriate.
  • the cross-sectional shape of the slope connecting the end of the first opening 11XA and the end of the second opening 11XB formed in the hole 11X in the film thickness direction is convex toward the center in the radial direction of the hole 11X. That is, the hole 11X has an inverted mortar-shaped cross section with a curved inclined surface.
  • the light-shielding layer 10X When the incident light in the diagonal direction is incident on the hole 11X of the light-shielding layer 10X, the light-shielding layer 10X satisfies the above formula (1).
  • the oblique incident light having the maximum incident angle ⁇ passes through the end portion of the first opening 11XA and the end portion of the second opening 11XB facing the radial direction of the hole 11X, and the hole. It does not enter the light receiving element 3 adjacent to 11X.
  • the cross-sectional shape of the slope connecting the end of the first opening 11YA and the end of the second opening 11YB formed in the hole 11Y in the film thickness direction As shown in FIG. 13, in the light-shielding layer 10Y according to the second modification, the cross-sectional shape of the slope connecting the end of the first opening 11YA and the end of the second opening 11YB formed in the hole 11Y in the film thickness direction. However, it is concave toward the center in the radial direction of the hole 11Y. That is, the hole 11X has an inverted bowl-shaped cross section with a curved inclined surface.
  • the light-shielding layer 10Y When the incident light in the diagonal direction is incident on the hole 11Y of the light-shielding layer 10Y, the light-shielding layer 10Y satisfies the above formula (1).
  • the incident light in the diagonal direction of the maximum incident angle ⁇ passes through the end portion of the first opening 11YA and the end portion of the second opening 11YB facing the radial direction of the hole 11Y, and the hole. It does not enter the light receiving element 3 adjacent to 11Y.
  • the optical fingerprint sensor 1 since the cross-sectional shape of the hole of the light-shielding layer is formed in an inverted tapered shape, the incident light in the diagonal direction to the adjacent light receiving element 3 is limited and crosstalk is performed. Can be reduced. According to the optical fingerprint sensor 1, crosstalk can be reduced while simplifying the device configuration by making the cross-sectional shape of the hole of the light-shielding layer into an inverted tapered shape.
  • the light-shielding layer 10 covering the transparent layer T transmits ultraviolet rays to the transparent layer T side and is surely cured, so that peeling at the boundary with the transparent layer T is prevented.
  • the cross section of the hole 11 is formed in an inverted tapered shape. Therefore, the incident of light which becomes noise to the adjacent light receiving element 3 is prevented, and the noise can be reduced.
  • Optical fingerprint sensor 2 Light receiving layer 3

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Abstract

An optical fingerprint sensor that is provided on the surface opposite from the viewing side of an organic EL display, said optical fingerprint sensor comprising: a light-receiving layer that has a plurality of light-receiving elements which are two-dimensionally arranged on a substrate; a transparent layer that is formed on the viewing side of the light-receiving layer; and a light-blocking layer that is formed on the surface of the transparent layer on the opposite side from the light-receiving layer, wherein holes are positioned in the light-blocking layer so as to correspond to the light-receiving elements, and the diameter of the holes is equal or becomes greater toward the transparent layer side in cross-sectional view in the thickness direction of the light-blocking layer.

Description

光学式指紋センサOptical fingerprint sensor
　本発明は、指紋を光学的に認識する光学式指紋センサに関する。
　本願は、２０２０年８月６日に日本に出願された特願２０２０－１３３９１０号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to an optical fingerprint sensor that optically recognizes a fingerprint.
This application claims priority based on Japanese Patent Application No. 2020-133910 filed in Japan on August 6, 2020, the contents of which are incorporated herein by reference.
　スマートフォン等のタッチパネルを用いたモバイル端末装置が普及しつつある。そのようなモバイル端末装置には、セキュリティを保護するロックを解除するために、ユーザの本人認証の操作が行われる場合がある。本人認証には様々な方法があり、その中で生体認証センサはユーザ本人を確実に認証する方法として採用されている。 Mobile terminal devices using touch panels such as smartphones are becoming widespread. In such a mobile terminal device, an operation of personal authentication of a user may be performed in order to release a lock that protects security. There are various methods for personal authentication, and among them, the biometric authentication sensor is adopted as a method for reliably authenticating the user himself / herself.
　例えば、特許文献１には、指の静脈を認識する生体認証センサが記載されている。生体認証センサは、例えば、複数の受光素子を有する受光層を備えている。受光層の受光素子において入射する光は、斜め方向にも進行するため隣接する受光素子にも入射してクロストークと呼ばれるノイズとなる。クロストークを低減して受光層の読み取り精度を向上させるために、受光層の上層に光を遮断する遮光層が用いられる場合がある。遮光層は、複数の受光素子の上方に複数の受光素子に対応する位置に複数の開口したホールが形成されている。 For example, Patent Document 1 describes a biometric authentication sensor that recognizes a finger vein. The biometric authentication sensor includes, for example, a light receiving layer having a plurality of light receiving elements. Since the light incident on the light receiving element of the light receiving layer also travels in the oblique direction, it also enters the adjacent light receiving element and becomes noise called crosstalk. In order to reduce crosstalk and improve the reading accuracy of the light receiving layer, a light blocking layer that blocks light may be used in the upper layer of the light receiving layer. In the light-shielding layer, a plurality of open holes are formed above the plurality of light-receiving elements at positions corresponding to the plurality of light-receiving elements.
　例えば、特許文献１に記載された技術によれば、受光層の上層に複数のホールが形成された遮光層を２層設けている。この２層の遮光層の上層において、複数のホールに対応する位置に複数のレンズを有するレンズ層を配置して入射光の進行方向を制限し、複数の受光素子に入射するクロストークを低減している。 For example, according to the technique described in Patent Document 1, two light-shielding layers in which a plurality of holes are formed are provided on the upper layer of the light-receiving layer. In the upper layer of these two light-shielding layers, a lens layer having a plurality of lenses is arranged at positions corresponding to a plurality of holes to limit the traveling direction of incident light and reduce crosstalk incident on a plurality of light receiving elements. ing.
日本国特開２０１０－０９４４９９号公報Japanese Patent Application Laid-Open No. 2010-094499
　近年、携帯端末のタッチパネルの表面と反対側の下層に設けられた生体認証として指紋を認識する光学式指紋センサが採用されつつある。携帯端末は、より薄型化されることが求められている。タッチパネルの下層に光学式指紋センサを設ける場合、センサの厚さはなるべく薄くすることが望ましい。特許文献１に記載された技術をタッチパネルの下層に設けられる光学式指紋センサに適用しようとすると、２層の遮光層を設けると共に、２層のレンズ層の上層にレンズ層が設けられているため、装置構成が複雑化すると共に、センサの厚みが増加する。 In recent years, an optical fingerprint sensor that recognizes a fingerprint is being adopted as a biometric authentication provided on the lower layer on the opposite side of the touch panel of the mobile terminal. Mobile terminals are required to be thinner. When an optical fingerprint sensor is provided under the touch panel, it is desirable that the thickness of the sensor be as thin as possible. When the technique described in Patent Document 1 is applied to an optical fingerprint sensor provided on a lower layer of a touch panel, a two-layer light-shielding layer is provided and a lens layer is provided on an upper layer of the two-layer lens layer. As the device configuration becomes complicated, the thickness of the sensor increases.
　本発明は、上記事情を鑑みてなされたものであり、構成を簡略化しつつ、入射光のクロストークを低減することができる光学式指紋センサを提供する。 The present invention has been made in view of the above circumstances, and provides an optical fingerprint sensor capable of reducing crosstalk of incident light while simplifying the configuration.
　有機ＥＬディスプレイの視認側とは反対面に設けられた光学式指紋センサであって、基材上に二次元に配列された複数の受光素子を有する受光層と、前記受光層の前記視認側に形成された透明層と、前記透明層の前記受光層とは反対側の面に形成された遮光層を備え、前記遮光層の膜厚方向の断面視において、前記遮光層には、前記受光素子に対応する位置にホール配置され、前記ホールの径は、前記透明層側に向かうほど同径以上となる、光学式指紋センサである。 An optical fingerprint sensor provided on a surface opposite to the visual recognition side of an organic EL display, the light receiving layer having a plurality of light receiving elements arranged two-dimensionally on a substrate, and the light receiving layer on the visual viewing side. A transparent layer formed and a light-shielding layer formed on a surface of the transparent layer opposite to the light-receiving layer are provided. This is an optical fingerprint sensor in which holes are arranged at positions corresponding to the above, and the diameter of the holes becomes the same or more toward the transparent layer side.
　本発明の一態様の前記ホールのうち、前記視認側の最表面に第１径を有する第１開口があり、前記透明層側の最表面に第２径を有する第２開口があり、前記遮光層の膜厚をｔ１、前記透明層の膜厚をｔ２、前記第２径をｄ１、隣接する前記受光素子間の間隔をｄ２、前記第２径と前記第１径との差の１／２をｘ、としたときに、条件式ｔ１／（ｄ１－ｘ）＞ｔ２／ｄ２を満たすように構成されていてもよい。 Among the holes according to one aspect of the present invention, there is a first opening having a first diameter on the outermost surface on the viewing side, and a second opening having a second diameter on the outermost surface on the transparent layer side, and the light shielding. The film thickness of the layer is t 1 , the film thickness of the transparent layer is t 2 , the second diameter is d 1 , the distance between adjacent light receiving elements is d 2 , and the difference between the second diameter and the first diameter. When 1/2 of the above is x, it may be configured to satisfy the conditional expression t 1 / (d 1 − x)> t 2 / d 2 .
　本発明の一態様の前記ホールは、前記遮光層の膜厚方向の断面形状において前記第１開口の端部と前記第２開口の端部とを結ぶ斜面が直線状に形成されていてもよい。 In the hole of one aspect of the present invention, the slope connecting the end of the first opening and the end of the second opening may be formed linearly in the cross-sectional shape of the light-shielding layer in the film thickness direction. ..
　本発明の一態様の前記ホールは、前記遮光層の膜厚方向の断面形状において前記第１開口の端部と前記第２開口の端部とを結ぶ斜面が前記ホールの径方向において径の中心に向かって凸状になるように形成されていてもよい。 In the hole of one aspect of the present invention, the slope connecting the end of the first opening and the end of the second opening in the cross-sectional shape of the light-shielding layer in the film thickness direction is the center of the diameter in the radial direction of the hole. It may be formed so as to be convex toward.
　本発明の一態様の前記ホールは、前記遮光層の膜厚方向の断面形状において前記第１開口の端部と前記第２開口の端部とを結ぶ斜面が前記ホールの径方向において径の中心に向かって凹状になるように形成されていてもよい。 In the hole of one aspect of the present invention, the slope connecting the end of the first opening and the end of the second opening in the cross-sectional shape of the light-shielding layer in the film thickness direction is the center of the diameter in the radial direction of the hole. It may be formed so as to be concave toward.
　上記本発明の態様によれば、構成を簡略化しつつ、入射光のクロストークを低減することができる。 According to the above aspect of the present invention, crosstalk of incident light can be reduced while simplifying the configuration.
本発明の実施形態に係る光学式指紋センサの使用状態を示す断面図である。It is sectional drawing which shows the use state of the optical fingerprint sensor which concerns on embodiment of this invention. 光学式指紋センサの構成を示す断面図である。It is sectional drawing which shows the structure of the optical fingerprint sensor. 遮光層の構成を示す平面図である。It is a top view which shows the structure of a light-shielding layer. 光学式指紋センサのＳ／Ｎ比を示す図である。It is a figure which shows the S / N ratio of an optical fingerprint sensor. 遮光層のホールの寸法を変更してクロストークの低減を計算した結果を示す図である。It is a figure which shows the result of having calculated the reduction of crosstalk by changing the dimension of the hole of a light-shielding layer. 遮光部における可視域の波長の光の透過率を示す図である。It is a figure which shows the transmittance of the light of the wavelength of a visible region in a light-shielding part. 遮光部における紫外域の波長の光の透過率を示す図である。It is a figure which shows the transmittance of the light of the wavelength of an ultraviolet region in a light-shielding part. 透過率が調整された材料により逆テーパ形状に形成された遮光部を示す断面図である。It is sectional drawing which shows the light-shielding part formed in the reverse taper shape by the material which adjusted the transmittance. 透過率が調整された材料により順テーパ形状に形成された遮光部を示す断面図である。It is sectional drawing which shows the light-shielding part formed in the forward taper shape by the material which adjusted the transmittance. カーボンブラックを含む材料により順テーパ形状に形成された遮光部を示す断面図である。It is sectional drawing which shows the light-shielding part formed in the forward taper shape by the material containing carbon black. カーボンブラックを含む材料により逆テーパ形状に形成された遮光部を示す断面図である。It is sectional drawing which shows the light-shielding part formed in the reverse taper shape by the material containing carbon black. 変形例１に係る遮光層の構成を示す断面図である。It is sectional drawing which shows the structure of the light-shielding layer which concerns on modification 1. FIG. 変形例２に係る遮光層の構成を示す断面図である。It is sectional drawing which shows the structure of the light-shielding layer which concerns on modification 2. FIG.
　以下、図面を参照しつつ、本発明に係る光学式指紋センサ及び光学式指紋センサの製造方法の実施形態について説明する。 Hereinafter, embodiments of the optical fingerprint sensor and the method for manufacturing the optical fingerprint sensor according to the present invention will be described with reference to the drawings.
　図１に示されるように、光学式指紋センサ１は、例えば、スマートフォンＳ等の携帯端末に設けられたディスプレイＣの視認側と反対側の面側に設けられている。ディスプレイＣは、自発光する画素により表示画像を表示する有機ＥＬディスプレイであり、既知の構成を有する。光学式指紋センサ１は、ディスプレイＣの光源（画素）に照らされた指紋Ｙから反射した光の強度を検出することで、指紋のパターンを検出する。ユーザは、ディスプレイＣに表示された領域に指先を触れ、光学式指紋センサ１に指紋を認識させる。 As shown in FIG. 1, the optical fingerprint sensor 1 is provided on the surface side opposite to the visual recognition side of the display C provided in a mobile terminal such as a smartphone S, for example. The display C is an organic EL display that displays a display image by self-luminous pixels, and has a known configuration. The optical fingerprint sensor 1 detects a fingerprint pattern by detecting the intensity of light reflected from the fingerprint Y illuminated by the light source (pixel) of the display C. The user touches the area displayed on the display C with a fingertip to cause the optical fingerprint sensor 1 to recognize the fingerprint.
　図２及び図３に示されるように、光学式指紋センサ１は、光の強度を検出する受光層２と、受光層２の受光側の面側である上層に設けられた遮光層１０とを備える。受光層２は、複数の受光素子３を有する。受光素子３は、光を受光しその強度を検出する。受光素子３は、受光した光の強度に比例した電圧を出力する。複数の受光素子３は、基材Ｍの受光側の面に二次元のマトリクス状に配列されている。隣接する受光素子３同士の間隔は、例えば、ディスプレイＣの画素の間隔に配置されている。 As shown in FIGS. 2 and 3, the optical fingerprint sensor 1 has a light receiving layer 2 for detecting the intensity of light and a light shielding layer 10 provided on an upper layer on the surface side of the light receiving layer 2 on the light receiving side. Be prepared. The light receiving layer 2 has a plurality of light receiving elements 3. The light receiving element 3 receives light and detects the intensity thereof. The light receiving element 3 outputs a voltage proportional to the intensity of the received light. The plurality of light receiving elements 3 are arranged in a two-dimensional matrix on the surface of the base material M on the light receiving side. The distance between the adjacent light receiving elements 3 is arranged, for example, at the distance between the pixels of the display C.
　受光素子３は、例えば、ディスプレイＣの面を視認側から法線方向に沿って見て円形に形成されている。受光素子３は、円形以外の形状に形成されていてもよい。基材Ｍは、例えば、シリコンウエハである。複数の受光素子３は、指紋から反射した光を受光して、指紋の凹凸により生じた反射光の強弱を検出し、指紋のパターンを検出する。受光層２の上層（すなわち、受光側の面側）には、透明層Ｔが設けられている。 The light receiving element 3 is formed in a circular shape, for example, when the surface of the display C is viewed from the viewing side along the normal direction. The light receiving element 3 may be formed in a shape other than a circle. The base material M is, for example, a silicon wafer. The plurality of light receiving elements 3 receive the light reflected from the fingerprint, detect the intensity of the reflected light generated by the unevenness of the fingerprint, and detect the fingerprint pattern. A transparent layer T is provided on the upper layer of the light receiving layer 2 (that is, the surface side on the light receiving side).
　透明層Ｔは、可視光領域を透過する光学フィルタである。透明層Ｔは、例えば、４μｍから５μｍの範囲の厚さに形成されている。透明層Ｔは、例えば厚みや屈折率等が異なる複数の透明な光学フィルタ層が積層されている。各層は、設定された波長域の可視光を干渉により相殺して遮蔽するように厚さや屈折率等が調整されている。すなわち透明層Ｔは、透明層Ｔの受光側から入射した光が、透明層Ｔの各層で段階的にそれぞれの波長域の光が遮断され、可視光領域が除去された所望の赤外線波長域の光が受光側の面と反対側の面側の受光層２に到達するような構成であることが好ましい。 The transparent layer T is an optical filter that transmits through the visible light region. The transparent layer T is formed, for example, to have a thickness in the range of 4 μm to 5 μm. The transparent layer T is laminated with, for example, a plurality of transparent optical filter layers having different thicknesses, refractive indexes, and the like. The thickness and refractive index of each layer are adjusted so as to offset and shield visible light in a set wavelength range by interference. That is, in the transparent layer T, the light incident from the light receiving side of the transparent layer T is gradually blocked from the light in each wavelength range in each layer of the transparent layer T, and the visible light region is removed in the desired infrared wavelength range. It is preferable that the light reaches the light receiving layer 2 on the surface side opposite to the surface on the light receiving side.
　透明層Ｔの上面（すなわち、受光側の面）には、光を遮光する遮光層１０が形成されている。遮光層１０は、例えば、１．５μｍ程度の厚さに形成されている。遮光層１０には、複数のホール１１が形成されている。ホール１１は、視認側から平面視して受光素子３に対応する位置に二次元のマトリクス状に配列されている。ホール１１は、例えば、受光素子３の径の３倍程度の径を有する。 A light-shielding layer 10 that blocks light is formed on the upper surface of the transparent layer T (that is, the surface on the light-receiving side). The light-shielding layer 10 is formed to have a thickness of, for example, about 1.5 μm. A plurality of holes 11 are formed in the light-shielding layer 10. The holes 11 are arranged in a two-dimensional matrix at positions corresponding to the light receiving element 3 when viewed in a plan view from the viewing side. The hole 11 has, for example, a diameter about three times the diameter of the light receiving element 3.
　複数のホール１１は、例えば、複数の受光素子３と同心に配置されるように記載されている。複数のホール１１の配置関係はこれに限らず、受光素子３がホール１１の際に配置されていてもよい。但し、この場合においても複数の受光素子３と複数のホール１１とのピッチは等差である。 The plurality of holes 11 are described so as to be arranged concentrically with the plurality of light receiving elements 3, for example. The arrangement relationship of the plurality of holes 11 is not limited to this, and the light receiving element 3 may be arranged at the time of the holes 11. However, even in this case, the pitches of the plurality of light receiving elements 3 and the plurality of holes 11 are arithmetic progressions.
　複数のホール１１は、光学式指紋センサ１の読取りの精度を向上するために設けられ、隣接するホール１１から受光素子３に斜め方向から光が入りにくくなるように絞りとして形成されている。複数のホール１１は、径の大きさが透明層Ｔ方向に向かうほど拡大するように端部の断面が逆テーパ形状に形成されている。逆テーパ形状とは、例えば、ホール１１の開口が受光層２側の方向に向かうほど径が同径以上となるような形状をいう。すなわち、ホール１１は、傾斜面が直線状の逆皿状断面に形成されている。さらに、逆テーパ形状とは、ホール１１の透明層Ｔと接する面における径がホール１１の透明層Ｔとは反対側の層に接する面における径よりも大きい状態と定義することもできる。 The plurality of holes 11 are provided to improve the reading accuracy of the optical fingerprint sensor 1, and are formed as a diaphragm so that light does not easily enter the light receiving element 3 from the adjacent holes 11 from an oblique direction. The cross sections of the ends of the plurality of holes 11 are formed in an inverted tapered shape so that the diameter increases toward the transparent layer T direction. The reverse taper shape means, for example, a shape in which the diameter becomes the same or more as the opening of the hole 11 toward the light receiving layer 2 side. That is, the hole 11 is formed in an inverted dish-shaped cross section having a linear inclined surface. Further, the reverse taper shape can be defined as a state in which the diameter of the surface of the hole 11 in contact with the transparent layer T is larger than the diameter of the surface of the hole 11 in contact with the layer opposite to the transparent layer T.
　透明樹脂層Ｊは、ホール１１を有する遮光層１０の透明層Ｔとは反対側の面に塗布され、複数のホール１１まで浸透する。透明樹脂層Ｊは、硬化後、遮光層１０をコーティングするように形成される。透明樹脂層Ｊは、例えば、光硬化樹脂を用いて形成されている。 The transparent resin layer J is applied to the surface of the light-shielding layer 10 having the holes 11 opposite to the transparent layer T, and penetrates into the plurality of holes 11. The transparent resin layer J is formed so as to coat the light-shielding layer 10 after curing. The transparent resin layer J is formed by using, for example, a photocurable resin.
　次にホール１１の形状について説明する。 Next, the shape of the hole 11 will be described.
　ホール１１は、斜め方向の入射光がホール１１に隣接するホールに対応する位置に配置された受光素子３に入射することを防止する。 The hole 11 prevents obliquely incident light from incident on the light receiving element 3 arranged at a position corresponding to the hole adjacent to the hole 11.
　ホール１１は、透明樹脂層Ｊ側の面（すなわち、視認側の最表面）に第１径の第１開口１１Ａが形成され、受光素子３側の面（すなわち、透明層Ｔ側の最表面）に第２径の第２開口１１Ｂが形成されている。第２開口１１Ｂの第２径は、第１開口１１Ａの第１径以上の大きさに形成されている。 In the hole 11, a first opening 11A having a first diameter is formed on the surface on the transparent resin layer J side (that is, the outermost surface on the visual recognition side), and the surface on the light receiving element 3 side (that is, the outermost surface on the transparent layer T side). A second opening 11B having a second diameter is formed therein. The second diameter of the second opening 11B is formed to have a size equal to or larger than the first diameter of the first opening 11A.
　ホール１１の膜厚方向の断面視における断面形状において、遮光層１０の膜厚をｔ１、透明層Ｔの膜厚をｔ２、第２開口１１Ｂの第２径をｄ１、隣接する受光素子３間の間隔をｄ２、逆テーパ形状の庇部分の距離（すなわち、第２開口１１Ｂの第２径と第１開口１１Ａの第１径との差の１／２）をｘ、としたときに、以下の条件式（１）を満たす。
　ｔ１／（ｄ１－ｘ）＞ｔ２／ｄ２　　　　（１） In the cross-sectional shape of the hole 11 in the cross-sectional view in the film thickness direction, the film thickness of the light-shielding layer 10 is t 1 , the film thickness of the transparent layer T is t 2 , the second diameter of the second opening 11B is d 1 , and the adjacent light receiving element. When the distance between 3 is d 2 and the distance between the eaves having the inverted taper shape (that is, 1/2 of the difference between the second diameter of the second opening 11B and the first diameter of the first opening 11A) is x. In addition, the following conditional expression (1) is satisfied.
t 1 / (d 1 -x)> t 2 / d 2 (1)
　式（１）において左辺は、第１開口１１Ａの端部と、ホール１１の径方向に対向する第２開口１１Ｂの端部とを結ぶ斜線を斜辺とする、直角三角形の底辺と対辺との比である。ここで、ｘ≧０である。条件式（１）において右辺は、隣接する受光素子３の間隔を底辺、透明層Ｔの厚さを対辺とする直角三角形の底辺と対辺との比である。 In formula (1), the left side is the ratio of the base to the opposite side of a right triangle whose hypotenuse is the hypotenuse connecting the end of the first opening 11A and the end of the second opening 11B facing in the radial direction of the hole 11. Is. Here, x ≧ 0. In the conditional equation (1), the right side is the ratio of the base to the opposite side of a right triangle having the distance between adjacent light receiving elements 3 as the base and the thickness of the transparent layer T as the opposite side.
　遮光層１０は、条件式（１）を満たすように、ホール１１のテーパ形状が設計され、ホール１１における斜め方向の入射角θが最大値である入射光がホール１１に入射した際に、隣接する受光素子３に光が入射することを防止しクロストークを低減する。条件式（１）に示す条件は、必ずしもホール１１に隣接する受光素子３に斜め方向の入射光が入射することを完全には防止しない。しかしながら、ホール１１の設計時に条件式（１）を当てはめることにより、クロストークが低減されるか否かが検証される。 The light-shielding layer 10 is adjacent to the light-shielding layer 10 when the tapered shape of the hole 11 is designed so as to satisfy the conditional expression (1) and the incident light having the maximum value of the incident angle θ in the diagonal direction in the hole 11 is incident on the hole 11. It prevents light from being incident on the light receiving element 3 and reduces crosstalk. The condition shown in the conditional expression (1) does not necessarily completely prevent the incident light in the oblique direction from being incident on the light receiving element 3 adjacent to the hole 11. However, by applying the conditional expression (1) at the time of designing the hole 11, it is verified whether or not the crosstalk is reduced.
　ホール１１に比して比較例に係る遮光層１０Ｈは、ホールの断面がホール１１の逆テーパ形状と開口の広がりの状態が逆の順テーパ形状に形成されている。遮光層１０Ｈのホールでは、透明樹脂層Ｊ側の開口の径よりも透明層Ｔ側の開口の径が大きい。比較例に係る遮光層１０Ｈの順テーパ形状のホールによれば、斜め方向の入射光が隣接するホール１１から受光素子３に入射し、クロストークが発生しやすくなる。 In the light-shielding layer 10H according to the comparative example as compared with the hole 11, the cross section of the hole is formed into a reverse taper shape of the hole 11 and a forward taper shape in which the state of the opening is reversed. In the hole of the light-shielding layer 10H, the diameter of the opening on the transparent layer T side is larger than the diameter of the opening on the transparent resin layer J side. According to the hole having a forward taper shape of the light-shielding layer 10H according to the comparative example, the incident light in the oblique direction is incident on the light receiving element 3 from the adjacent hole 11, and crosstalk is likely to occur.
　図４に示されるように、遮光層１０は、順テーパ形状に形成されたホールを有する遮光層１０Ｈに比してＳ／Ｎ比が改善され、ノイズ（クロストーク）が大幅に低減されている。 As shown in FIG. 4, the light-shielding layer 10 has an improved S / N ratio and significantly reduced noise (crosstalk) as compared with the light-shielding layer 10H having holes formed in a forward taper shape. ..
　図５には、遮光層１０のホール１１の第２開口１１Ｂの第２径の大きさｄ１を固定して他の上記各寸法を変更した実施例及び比較例の計算結果が示されている。計算結果に示されるように、ホール１１において、第２開口１１Ｂの第２径が第１開口１１Ａの第１径以上である場合、条件式（１）を満たし、クロストークが低減される。 FIG. 5 shows the calculation results of Examples and Comparative Examples in which the size d 1 of the second diameter of the second opening 11B of the hole 11 of the light-shielding layer 10 is fixed and the other dimensions are changed. .. As shown in the calculation result, when the second diameter of the second opening 11B is equal to or larger than the first diameter of the first opening 11A in the hole 11, the conditional expression (1) is satisfied and the crosstalk is reduced.
　次に、遮光層１０の物性について説明する。 Next, the physical characteristics of the light-shielding layer 10 will be described.
　遮光層１０は、黒色の遮光性物質が混入された光硬化樹脂により形成されている。光硬化樹脂は、透明であり、紫外線が照射されると硬化する感光性材料である。遮光層１０は、硬化前は遮光性物質である黒色顔料が混入された光硬化樹脂である。この光硬化樹脂は、透明層Ｔの受光側の面に塗布される。塗布された黒色顔料が混入された光硬化樹脂の受光側の面側に複数のホール１１部分を覆うフォトマスクを当てパターニング処理し、受光側（すなわち、透明層Ｔと反対側の面）から紫外線を照射する。そうすると、複数のホール１１部分以外の部分の光硬化樹脂が硬化する。そして、複数のホール１１部分における未硬化の光硬化樹脂を除去すると遮光層１０が形成される。 The light-shielding layer 10 is formed of a photocurable resin mixed with a black light-shielding substance. The photocurable resin is a photosensitive material that is transparent and cures when irradiated with ultraviolet rays. The light-shielding layer 10 is a photo-curing resin mixed with a black pigment which is a light-shielding substance before curing. This photocurable resin is applied to the surface of the transparent layer T on the light receiving side. A photomask covering a plurality of holes 11 is applied to the surface side of the photocurable resin mixed with the applied black pigment on the light receiving side to perform patterning processing, and ultraviolet rays are applied from the light receiving side (that is, the surface opposite to the transparent layer T). Irradiate. Then, the photocurable resin in the portion other than the plurality of holes 11 is cured. Then, when the uncured photocurable resin in the plurality of holes 11 is removed, the light-shielding layer 10 is formed.
　ここで、上述したように、遮光層１０は遮光性を確保しつつ、硬化後に透明層Ｔとの間の剥離を防止するために透明層Ｔとの接触面にも紫外線を到達させる必要がある。そこで、本実施形態では、遮光層１０は、赤外線領域を含む可視光領域の波長の光を遮断しつつ、紫外線領域の波長の光をわずかに透過することが好ましい。 Here, as described above, it is necessary for the light-shielding layer 10 to allow ultraviolet rays to reach the contact surface with the transparent layer T in order to prevent peeling from the transparent layer T after curing while ensuring the light-shielding property. .. Therefore, in the present embodiment, it is preferable that the light-shielding layer 10 slightly transmits light having a wavelength in the ultraviolet region while blocking light having a wavelength in the visible light region including an infrared region.
　図６及び図７に示されるように、遮光層１０は、波長４００ｎｍから７００ｎｍの範囲の光の透過率が１％以下であり、且つ、波長３６０ｎｍから４００ｎｍの範囲の光の透過率が０．０５％以上であることが好ましい。このような透過率を実現するために、遮光層１０には、例えば、窒化チタン、酸窒化チタン、酸化チタン、及び炭化チタンのうち少なくとも１つを主成分とする黒色顔料が含まれる。遮光層１０の透過率は、膜厚により変化する。透過率は、膜厚が厚くなると低下する。 As shown in FIGS. 6 and 7, the light-shielding layer 10 has a light transmittance in the wavelength range of 400 nm to 700 nm of 1% or less, and a light transmittance in the wavelength range of 360 nm to 400 nm is 0. It is preferably 05% or more. In order to realize such a transmittance, the light-shielding layer 10 contains, for example, a black pigment containing at least one of titanium nitride, titanium oxynitride, titanium oxide, and titanium carbide as a main component. The transmittance of the light-shielding layer 10 changes depending on the film thickness. The transmittance decreases as the film thickness increases.
　図８に示されるように、上記の材料により形成された逆テーパ形状を有する遮光層１０は、光硬化に用いる紫外線（例えば、波長３６５ｎｍ）の透過を妨げないため、硬化時に紫外線が照射されると透明層Ｔとの境界まで紫外線が到達し、透明層Ｔの受光側の面側に硬化した膜として形成される。 As shown in FIG. 8, the light-shielding layer 10 having a reverse-tapered shape formed of the above-mentioned material does not interfere with the transmission of ultraviolet rays (for example, wavelength 365 nm) used for photo-curing, and is therefore irradiated with ultraviolet rays during curing. Ultraviolet rays reach the boundary between the transparent layer T and the transparent layer T, and are formed as a cured film on the surface side of the transparent layer T on the light receiving side.
　ホール１１のマスクをして紫外線を照射する際に、膜厚、露光時間、硬化時間のバランスを調整することにより、ホール１１のテーパ形状のテーパ角が調整される。テーパ角は、上述したように、ホール１１の庇部分の距離ｘの大きさにより決定される。 When the hole 11 is masked and irradiated with ultraviolet rays, the taper angle of the tapered shape of the hole 11 is adjusted by adjusting the balance between the film thickness, the exposure time, and the curing time. As described above, the taper angle is determined by the size of the distance x of the eaves portion of the hole 11.
　遮光層１０の硬化時において紫外線の露光時間を減少させると、遮光層１０において透明層Ｔまで到達する紫外線の経時的な光量が減少し、ホール１１において距離ｘが大きい逆テーパ形状に形成できる。遮光層１０の硬化時において紫外線の露光時間を増加させると、遮光層１０において透明層Ｔまで到達する紫外線の経時的な光量が増加し、ホール１１において距離ｘが小さい逆テーパ形状に形成できる。硬化後の遮光層１０は、赤外線領域を含む可視光領域の波長の光を遮断し、複数のホール１１部分からのみ光を透明層Ｔ側に透過させる。 When the exposure time of ultraviolet rays is reduced when the light-shielding layer 10 is cured, the amount of ultraviolet rays reaching the transparent layer T in the light-shielding layer 10 with time decreases, and the hole 11 can be formed into a reverse tapered shape having a large distance x. When the exposure time of ultraviolet rays is increased when the light-shielding layer 10 is cured, the amount of ultraviolet rays reaching the transparent layer T in the light-shielding layer 10 with time increases, and the hole 11 can be formed into a reverse tapered shape having a small distance x. The cured light-shielding layer 10 blocks light having a wavelength in the visible light region including an infrared region, and transmits light to the transparent layer T side only from a plurality of holes 11 portions.
　図９に示されるように、紫外線の露光時間等を調整することにより遮光層１０は、ホール１１が順テーパ形状にも形成される。 As shown in FIG. 9, in the light-shielding layer 10, the holes 11 are formed in a forward-tapered shape by adjusting the exposure time of ultraviolet rays and the like.
　遮光層１０は、カーボンブラックを含む黒色顔料により形成されていてもよい。このような遮光層は、上記の材料に比して透明層Ｔ側に紫外線が到達しにくい。 The light-shielding layer 10 may be formed of a black pigment containing carbon black. In such a light-shielding layer, ultraviolet rays are less likely to reach the transparent layer T side than the above-mentioned materials.
　図１０に示されるように、カーボンブラックを含む黒色顔料を含む材料を用いて遮光層１０を形成する場合、透明層Ｔ側に紫外線が到達するように露光時間を十分に調整すると順テーパ形状のホール１１を有する遮光層１０が形成される。 As shown in FIG. 10, when the light-shielding layer 10 is formed by using a material containing a black pigment containing carbon black, if the exposure time is sufficiently adjusted so that the ultraviolet rays reach the transparent layer T side, a forward taper shape is formed. The light-shielding layer 10 having the holes 11 is formed.
　図１１に示されるように、カーボンブラックを含む黒色顔料を用いて逆テーパ形状の遮光層１０を形成する場合、対象物を覆うように形成する際に、対象物との間の境界に剥離が生じる場合がある。従って、上記の通り、紫外線領域の波長の光をわずかに透過する材料により形成された遮光層１０によれば、透明層Ｔとの境界における剥離が防止される。そのため、逆テーパ形状の遮光層１０は、上記のような材料を用いて形成されることが望ましい。 As shown in FIG. 11, when the reverse-tapered light-shielding layer 10 is formed by using a black pigment containing carbon black, peeling occurs at the boundary between the object and the object when the light-shielding layer 10 is formed so as to cover the object. May occur. Therefore, as described above, the light-shielding layer 10 formed of a material that slightly transmits light having a wavelength in the ultraviolet region prevents peeling at the boundary with the transparent layer T. Therefore, it is desirable that the light-shielding layer 10 having a reverse taper shape is formed by using the above-mentioned material.
［変形例１］
　以下、遮光層１０の変形例１について説明する。
　上記実施形態においては、クロストークを防止するように、ホール１１の断面において、斜面が直線状の逆テーパ形状に形成される条件を示した。遮光層の形成工程においては、上記実施形態の遮光層１０の理想的なホール１１の逆テーパ形状が形成されるとは限らず、変形して形成される場合もあり得る。変形例においては、遮光層１０と同じ効果を奏しつつ、変形した逆テーパ形状に形成されている例を示す。以下の説明では、上記実施形態と同一の構成については同一の名称、符号を用い、重複する説明については適宜省略する。 [Modification 1]
Hereinafter, modification 1 of the light-shielding layer 10 will be described.
In the above embodiment, the condition that the slope is formed into a linear inverted tapered shape in the cross section of the hole 11 is shown so as to prevent crosstalk. In the step of forming the light-shielding layer, the reverse taper shape of the ideal hole 11 of the light-shielding layer 10 of the above embodiment is not always formed, and it may be deformed and formed. In the modified example, an example in which the light-shielding layer 10 is formed into a deformed reverse taper shape while having the same effect as the light-shielding layer 10 is shown. In the following description, the same name and reference numeral will be used for the same configuration as the above embodiment, and duplicate description will be omitted as appropriate.
　図１２に示されるように、変形例１に係る遮光層１０Ｘでは、膜厚方向においてホール１１Ｘに形成された第１開口１１ＸＡの端部と第２開口１１ＸＢの端部とを結ぶ斜面の断面形状が、ホール１１Ｘの径方向において中心方向に向かって凸状である。すなわち、ホール１１Ｘは、傾斜面が曲線的な逆すり鉢状断面になっている。 As shown in FIG. 12, in the light-shielding layer 10X according to the first modification, the cross-sectional shape of the slope connecting the end of the first opening 11XA and the end of the second opening 11XB formed in the hole 11X in the film thickness direction. However, it is convex toward the center in the radial direction of the hole 11X. That is, the hole 11X has an inverted mortar-shaped cross section with a curved inclined surface.
　遮光層１０Ｘのホール１１Ｘに斜め方向の入射光が入射した場合、遮光層１０Ｘは、上記式（１）を満たす。ホール１１Ｘでは、入射する最大の入射角θの斜め方向の入射光が、第１開口１１ＸＡの端部と、ホール１１Ｘの径方向に対向する第２開口１１ＸＢの端部とを通過すると共に、ホール１１Ｘに隣接する受光素子３に入射しない。 When the incident light in the diagonal direction is incident on the hole 11X of the light-shielding layer 10X, the light-shielding layer 10X satisfies the above formula (1). In the hole 11X, the oblique incident light having the maximum incident angle θ passes through the end portion of the first opening 11XA and the end portion of the second opening 11XB facing the radial direction of the hole 11X, and the hole. It does not enter the light receiving element 3 adjacent to 11X.
［変形例２］ [Modification 2]
　以下、遮光層１０の変形例２について説明する。
　図１３に示されるように、変形例２に係る遮光層１０Ｙでは、膜厚方向においてホール１１Ｙに形成された第１開口１１ＹＡの端部と第２開口１１ＹＢの端部とを結ぶ斜面の断面形状が、ホール１１Ｙの径方向において中心方向に向かって凹状である。すなわち、ホール１１Ｘは、傾斜面が曲線的な逆碗状断面になっている。 Hereinafter, modification 2 of the light-shielding layer 10 will be described.
As shown in FIG. 13, in the light-shielding layer 10Y according to the second modification, the cross-sectional shape of the slope connecting the end of the first opening 11YA and the end of the second opening 11YB formed in the hole 11Y in the film thickness direction. However, it is concave toward the center in the radial direction of the hole 11Y. That is, the hole 11X has an inverted bowl-shaped cross section with a curved inclined surface.
　遮光層１０Ｙのホール１１Ｙに斜め方向の入射光が入射した場合、遮光層１０Ｙは、上記式（１）を満たす。ホール１１Ｙでは、入射する最大の入射角θの斜め方向の入射光が、第１開口１１ＹＡの端部と、ホール１１Ｙの径方向に対向する第２開口１１ＹＢの端部とを通過すると共に、ホール１１Ｙに隣接する受光素子３に入射しない。 When the incident light in the diagonal direction is incident on the hole 11Y of the light-shielding layer 10Y, the light-shielding layer 10Y satisfies the above formula (1). In the hole 11Y, the incident light in the diagonal direction of the maximum incident angle θ passes through the end portion of the first opening 11YA and the end portion of the second opening 11YB facing the radial direction of the hole 11Y, and the hole. It does not enter the light receiving element 3 adjacent to 11Y.
　上述したように、光学式指紋センサ１によれば、遮光層のホールの断面形状が逆テーパ形状に形成されているため、隣接する受光素子３への斜め方向の入射光を制限し、クロストークを低減することができる。上記光学式指紋センサ１によれば、遮光層のホールの断面形状を逆テーパ形状にすることで装置構成を簡略化しつつもクロストークを低減することができる。 As described above, according to the optical fingerprint sensor 1, since the cross-sectional shape of the hole of the light-shielding layer is formed in an inverted tapered shape, the incident light in the diagonal direction to the adjacent light receiving element 3 is limited and crosstalk is performed. Can be reduced. According to the optical fingerprint sensor 1, crosstalk can be reduced while simplifying the device configuration by making the cross-sectional shape of the hole of the light-shielding layer into an inverted tapered shape.
　上記光学式指紋センサ１によれば、透明層Ｔを覆う遮光層１０では、透明層Ｔ側に紫外線が透過して確実に硬化するため、透明層Ｔとの境界における剥離が防止される。上記光学式指紋センサ１によれば、ホール１１の断面が逆テーパ状に形成されている。そのため、隣接する受光素子３へのノイズとなる光の入射が防止され、ノイズを低減することができる。 According to the optical fingerprint sensor 1, the light-shielding layer 10 covering the transparent layer T transmits ultraviolet rays to the transparent layer T side and is surely cured, so that peeling at the boundary with the transparent layer T is prevented. According to the optical fingerprint sensor 1, the cross section of the hole 11 is formed in an inverted tapered shape. Therefore, the incident of light which becomes noise to the adjacent light receiving element 3 is prevented, and the noise can be reduced.
　以上、本発明の一実施形態について説明したが、本発明は上記の一実施形態に限定されるものではなく、その趣旨を逸脱しない範囲で適宜変更可能である。 Although one embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned one embodiment and can be appropriately modified without departing from the spirit of the present invention.
１　光学式指紋センサ
２　受光層
３　受光素子
１０、１０Ｈ、１０Ｘ、１０Ｙ　遮光層
１１、１１Ｘ、１１Ｙ　ホール
１１Ａ、１１ＸＡ、１１ＹＡ　第１開口
１１Ｂ、１１ＸＢ、１１ＹＢ　第２開口
Ｃ　ディスプレイ
ＥＬ　有機
Ｊ　透明樹脂層
Ｍ　基材
Ｓ　スマートフォン
Ｔ　透明層 1 Optical fingerprint sensor 2 Light receiving layer 3 Light receiving element 10, 10H, 10X, 10Y Light shielding layer 11, 11X, 11Y Hall 11A, 11XA, 11YA First opening 11B, 11XB, 11YB Second opening C Display EL Organic J Transparent resin layer M Base material S Smartphone T Transparent layer

Claims (5)

  1. 　有機ＥＬディスプレイの視認側とは反対側の面に設けられた光学式指紋センサであって、
    　基材上に二次元に配列された複数の受光素子を有する受光層と、
    　前記受光層の前記視認側に形成された透明層と、
    　前記透明層の前記受光層とは反対側の面に形成された遮光層を備え、
    　前記遮光層には前記受光素子に対応する位置にホールが配置され、
    　前記遮光層の膜厚方向の断面視において、前記ホールの径は前記透明層側に向かうほど同径以上となる、
    光学式指紋センサ。     An optical fingerprint sensor provided on the surface of the organic EL display opposite to the visual recognition side.
    A light receiving layer having a plurality of light receiving elements arranged two-dimensionally on a base material,
    A transparent layer formed on the visible side of the light receiving layer and
    A light-shielding layer formed on the surface of the transparent layer opposite to the light-receiving layer is provided.
    A hole is arranged in the light-shielding layer at a position corresponding to the light-receiving element.
    In a cross-sectional view of the light-shielding layer in the film thickness direction, the diameter of the hole becomes the same or larger toward the transparent layer side.
    Optical fingerprint sensor.
  2. 　前記ホールのうち、前記視認側の最表面に第１径を有する第１開口があり、前記透明層側の最表面に第２径を有する第２開口があり、
    　前記遮光層の膜厚をｔ１、前記透明層の膜厚をｔ２、前記第２径をｄ１、隣接する前記受光素子間の間隔をｄ２、前記第２径と前記第１径との差の１／２をｘ、としたときに、条件式
    　ｔ１／（ｄ１－ｘ）＞ｔ２／ｄ２
    を満たす、
    請求項１に記載の光学式指紋センサ。     Among the holes, the outermost surface on the visual recognition side has a first opening having a first diameter, and the outermost surface on the transparent layer side has a second opening having a second diameter.
    The film thickness of the light-shielding layer is t 1 , the film thickness of the transparent layer is t 2 , the second diameter is d 1 , the distance between adjacent light receiving elements is d 2 , and the second diameter and the first diameter are used. Conditional expression t 1 / (d 1 − x)> t 2 / d 2 when 1/2 of the difference between
    Meet, meet
    The optical fingerprint sensor according to claim 1.
  3. 　前記ホールは、前記遮光層の膜厚方向の断面形状において前記第１開口の端部と前記第２開口の端部とを結ぶ斜面が直線状である、
    請求項２に記載の光学式指紋センサ。     The hole has a linear slope connecting the end of the first opening and the end of the second opening in the cross-sectional shape of the light-shielding layer in the film thickness direction.
    The optical fingerprint sensor according to claim 2.
  4. 　前記ホールは、前記遮光層の膜厚方向の断面形状において、前記第１開口の端部と前記第２開口の端部とを結ぶ斜面が、前記ホールの径方向において径の中心に向かって凸状である、
    請求項２に記載の光学式指紋センサ。     In the hole, the slope connecting the end of the first opening and the end of the second opening is convex toward the center of the diameter in the radial direction of the hole in the cross-sectional shape of the light-shielding layer in the film thickness direction. Is like
    The optical fingerprint sensor according to claim 2.
  5. 　前記ホールは、前記遮光層の膜厚方向の断面形状において、前記第１開口の端部と前記第２開口の端部とを結ぶ斜面が、前記ホールの径方向において径の中心に向かって凹状である、
    請求項２に記載の光学式指紋センサ。     In the hole, the slope connecting the end of the first opening and the end of the second opening is concave toward the center of the diameter in the radial direction of the hole in the cross-sectional shape of the light-shielding layer in the film thickness direction. Is,
    The optical fingerprint sensor according to claim 2.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001223846A (en) * 2000-02-10 2001-08-17 Sharp Corp Image sensor and it manufacturing method
JP2008212311A (en) * 2007-03-02 2008-09-18 Ricoh Co Ltd Biometrics device
JP2009250705A (en) * 2008-04-03 2009-10-29 Fujitsu Ltd Light guiding mechanism for illumination sensor and mobile phone
JP2010098055A (en) * 2008-10-15 2010-04-30 Hitachi Maxell Ltd Light-shielding structure, imaging apparatus, method for manufacturing the same, and biological information acquisition apparatus
JP2016015173A (en) * 2015-10-22 2016-01-28 セイコーエプソン株式会社 Image acquisition device, biometric authentication device, and electronic apparatus
US20200089928A1 (en) * 2018-09-06 2020-03-19 Shenzhen GOODIX Technology Co., Ltd. Optical image capturing unit, optical image capturing system and electronic device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001223846A (en) * 2000-02-10 2001-08-17 Sharp Corp Image sensor and it manufacturing method
JP2008212311A (en) * 2007-03-02 2008-09-18 Ricoh Co Ltd Biometrics device
JP2009250705A (en) * 2008-04-03 2009-10-29 Fujitsu Ltd Light guiding mechanism for illumination sensor and mobile phone
JP2010098055A (en) * 2008-10-15 2010-04-30 Hitachi Maxell Ltd Light-shielding structure, imaging apparatus, method for manufacturing the same, and biological information acquisition apparatus
JP2016015173A (en) * 2015-10-22 2016-01-28 セイコーエプソン株式会社 Image acquisition device, biometric authentication device, and electronic apparatus
US20200089928A1 (en) * 2018-09-06 2020-03-19 Shenzhen GOODIX Technology Co., Ltd. Optical image capturing unit, optical image capturing system and electronic device

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