JP2012222484A - Sensing device and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To thin a device while suppressing incidence of direct light from a light emitting layer and scattered light made incident obliquely from an object on a light receiving surface of a light receiving element.SOLUTION: A light emitting part 20 includes a light emitting layer 26 which emits irradiation light IL, a first electrode 22 which transmits the irradiation light IL and reflected light RL, and second and third electrodes 24 which shield the irradiation light IL and the reflected light RL and are provided away from each other. The light receiving part 30 includes a light receiving element D which receives the reflected light RL. A light shielding layer BM shields the irradiation light and the reflected light, and has an opening. An insulation layer 28 is an insulator which covers the light shielding layer BM and transmits the irradiation light and the reflected light. In the plane view from the side of an object F, the light shielding layer BM and the insulation layer 28 overlap with the separation region between the second and third electrodes 24, and the light receiving surface of the light receiving element D is positioned inside the opening of the light shielding layer BM. In the insulation layer 28, a surface in contact with the light emitting layer 26 includes a slope inclined to a surface of the first electrode 22, and an angle formed by the slope and a surface in contact with the first electrode 22 is an acute angle.

Description

  The present invention relates to a sensing device and an electronic apparatus that irradiates an object with light and receives reflected light.

  In a biometric authentication device or an image scanner, a light emitting unit and a light receiving unit are arranged on the same side with respect to an object (for example, a finger or a document) placed on the reading area, and the light emitting unit is disposed on the object. In some cases, an image of an object is read by irradiating light from the light source and receiving the reflected light by a light receiving unit. For example, an imaging apparatus 101 described in Patent Document 1 includes a light source unit 111 (light emitting unit), a detection element 113 (light receiving unit), and a light shielding layer 126 for each pixel 110, and sequentially from the imaging target 129 side, By arranging the light shielding layer 126 and the detection element 113, the light shielding layer 126 partially shields light between the light source unit 111 and the detection element 113, and prevents direct light from the light source unit 111 from entering the detection element 113. At the same time, scattered light obliquely incident on the detection element 113 from the imaging target 129 is reduced. The imaging device 101 has a structure in which a glass substrate 124 on which a light source unit 111 is formed and a glass substrate 125 on which a light shielding layer 126 is formed are bonded together.

Japanese Patent Laying-Open No. 2009-3821 (FIG. 3, paragraphs 0031 to 0035)

However, in the imaging device 101 described in Patent Document 1, the thickness of the device increases because the glass substrate 125 on which the light shielding layer 126 is formed is interposed between the light source unit 111 and the detection element 113.
The present invention has been made in view of the above-described problems, and thins the apparatus while suppressing direct light from a light emitting layer or scattered light incident obliquely from an object from entering a light receiving surface of a light receiving element. It is an object of the present invention to provide a sensing device that can be used, and an electronic device using the sensing device.

  In order to solve the above problems, a sensing device according to a first aspect of the present invention includes a light emitting unit, a light receiving unit, a light shielding layer, and an insulating layer, irradiates light from the light emitting unit to an object, and In the sensing device that receives reflected light from an object by the light receiving unit, the light emitting unit and the light receiving unit are provided on the same side with respect to the object, and the light emitting unit is closer to the object side than the light receiving unit. And the light emitting unit is a light emitting layer that emits irradiation light that irradiates the object, a first electrode that is positioned closer to the object than the light emitting layer and transmits the irradiation light and the reflected light, and A second electrode and a third electrode, which are located on the light receiving part side of the light emitting layer and shield the irradiation light and the reflected light and are spaced apart from each other, the light receiving part receiving the reflected light The light-shielding layer , Provided in a position corresponding to a separation region between the second electrode and the third electrode on the light emitting layer side surface of the first electrode, and shields the irradiation light and the reflected light and forms an opening. The insulating layer is an insulator that is provided at a position corresponding to the separation region, covers the light shielding layer and transmits the irradiation light and the reflected light, and when viewed in plan from the object side, The light shielding layer and the insulating layer overlap with the separation region, the light receiving surface of the light receiving element is located in the opening, and the surface of the insulating layer that contacts the light emitting layer is inclined with respect to the surface of the first electrode The angle between the inclined surface and the surface in contact with the first electrode is an acute angle.

  According to this configuration, the second electrode, the third electrode, and the light shielding layer have a function of shielding the irradiation light and the reflected light. The insulating layer has at least a portion corresponding to a separation region between the second electrode and the third electrode (that is, a portion corresponding to the light receiving surface of the light receiving element) in the light emitting layer when viewed in plan from the object side. In a non-light emitting area that does not emit irradiated light. Therefore, it is possible to suppress the irradiation light emitted from the light emitting layer (light emitting region) from directly entering the light receiving surface of the light receiving element through the separated region. Further, since the second electrode, the third electrode, and the light shielding layer shield light from portions other than the opening when viewed from the object side, reflected light (scattered light) incident obliquely from the object is received by the light receiving element. It is also possible to suppress the incidence on the light receiving surface. Further, since the light shielding layer is provided between the second electrode, the third electrode, and the first electrode (within the light emitting unit), as described in Patent Document 1, the light source unit 111 (light emitting unit) and the detection element 113 are provided. There is no need to interpose the glass substrate 125 on which the light shielding layer 126 is formed between the (light receiving portions). Therefore, it is possible to reduce the thickness of the sensing device while suppressing direct light from the light emitting layer and scattered light incident obliquely from the object from entering the light receiving surface of the light receiving element.

  Moreover, according to said structure, the light shielding layer provided in the surface (light emitting layer side) of the 1st electrode is covered with an insulating layer. In the insulating layer, the surface in contact with the light emitting layer includes an inclined surface inclined with respect to the surface of the first electrode, and the angle formed by the inclined surface and the surface in contact with the first electrode is an acute angle. Therefore, when the light emitting layer is formed on the surface of the first electrode after laminating the light shielding layer and the insulating layer, the light emitting layer can be formed without causing breakage. A short circuit or leakage between the third electrode and the first electrode can be prevented.

  The target object may be a part of a living body (for example, a finger, palm, back of the hand, eyes, etc.), paper on which a document or image is printed, an OHP (OverHead Projector) sheet, or the like. . Further, the wavelength of light emitted from the light emitting layer can be arbitrarily determined. That is, the irradiation light and the reflected light may be, for example, near infrared light or visible light. In addition, the first to third electrodes may be such that the first electrode is an anode and the second electrode and the third electrode are cathodes, the first electrode is a cathode and the second and third electrodes are anodes. Also good. Further, the shape of the opening and the light receiving surface can be arbitrarily determined such as a rectangle, a circle, an ellipse, and a hexagon. In addition, the size of the opening and the size of the light receiving surface may be larger in the opening than in the light receiving surface, or vice versa, or both may be the same size. Further, it is not always necessary that the entire light receiving surface is located in the opening, and it is sufficient that at least a part of the light receiving surface is located in the opening. The acute angle is an angle smaller than a right angle (90 degrees).

  In addition, a sensing device according to a second aspect of the present invention includes a light emitting unit, a light receiving unit, a plurality of light shielding layers, and a plurality of insulating layers, irradiates light from the light emitting unit to the object, and the object In the sensing device that receives reflected light from the light receiving unit, the light emitting unit and the light receiving unit are provided on the same side with respect to the object, and the light emitting unit is located on the object side from the light receiving unit. The light emitting unit includes a light emitting layer that emits irradiation light that irradiates the object, a first electrode that is positioned closer to the object than the light emitting layer and transmits the irradiation light and the reflected light, and the light emitting layer A plurality of second electrodes that are positioned closer to the light receiving unit, shield the irradiation light and the reflected light, and are spaced apart from each other, and the light receiving unit receives the reflected light. Each of the plurality of light shielding layers. Is provided at a position corresponding to each of the separated regions existing between the adjacent second electrodes on the light emitting layer side surface of the first electrode, and shields the irradiation light and the reflected light and 1 The openings are formed, and each of the plurality of insulating layers is an insulator that is provided at a position corresponding to each of the separation regions, covers the light shielding layer, and transmits the irradiation light and the reflected light. When viewed in plan from the object side, each of the separation regions overlaps the light shielding layer and the insulating layer, and one light receiving surface of the light receiving element is located in each of the openings, In each of the insulating layers, a surface in contact with the light emitting layer includes an inclined surface inclined with respect to the surface of the first electrode, and an angle formed by the inclined surface and the surface in contact with the first electrode is an acute angle. And

  As described above, a configuration in which a plurality of second electrodes, light receiving elements, light shielding layers (openings), and insulating layers are provided may be employed. Also in this case, the same effect as that of the sensing device according to the first aspect is obtained. Note that the number of openings and the number of light receiving elements do not necessarily match, and the number of light receiving elements may be larger than the number of openings.

  In any of the sensing devices described above, the light shielding layer may be an insulator. If the light shielding layer is made of an insulator, the thickness of the portion where the light shielding layer and the insulating layer are stacked can be made thinner than when the light shielding layer is not an insulator.

In the sensing device according to the second aspect, a driving circuit that selects one or a plurality of the second electrodes as a target for supplying a driving signal for causing the light emitting layer to emit light among the plurality of second electrodes. You may prepare.
In this case, when viewed in plan from the object side, the portion corresponding to the one or more second electrodes selected by the drive circuit in the light emitting layer can be caused to emit light. Therefore, for example, only the part corresponding to a part of the second electrodes in the light emitting layer can be made to emit light all at once, thereby limiting the emission range of the irradiation light to a part. In addition, the portions corresponding to all the second electrodes in the light emitting layer can emit light all at once, or the second electrodes can be selected one by one in order and the portions corresponding to the selected second electrodes can be caused to emit light sequentially. it can.

  In any one of the sensing devices described above, the light emitting layer may be formed over the entire imaging region for imaging the object. In this case, since the patterning of the light emitting layer is unnecessary, the yield in the manufacturing process can be reduced. In addition, leakage between the first electrode and the second electrode can be suppressed.

  In any of the sensing devices described above, the light emitting layer may emit near infrared light. That is, the irradiation light and the reflected light may be near infrared light. In this case, a vein image can be generated by irradiating a part of the living body with near-infrared light and receiving the reflected light.

  An electronic device according to the present invention includes any one of the sensing devices described above. Electronic devices include, for example, various types of biometric authentication devices that perform biometric authentication based on veins, fingerprints, retinas, irises, and the like, and image reading devices such as image scanners, copiers, facsimiles, and barcode readers. Further, the electronic device may be a personal computer or a mobile phone provided with a biometric authentication function.

It is a block diagram which shows the structure of a biometrics authentication apparatus. It is sectional drawing of a sensing unit. FIG. 3 is an enlarged view of the insulating layer shown in FIG. 2. It is a top view which shows arrangement | positioning of a cathode, a light shielding layer, an insulating layer, and a light receiving element. It is a schematic diagram which shows arrangement | positioning of each layer at the time of paying attention to one light receiving element. It is a figure which shows the circuit structure of a light emission part. It is a figure for demonstrating the leak between an anode and a cathode. It is a top view which shows the modification of arrangement | positioning of a cathode, a light shielding layer, an insulating layer, and a light receiving element.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the ratio of dimensions of each layer and each member is appropriately different from the actual one.
<1. Embodiment>
FIG. 1 is a block diagram showing the configuration of the biometric authentication device 1.
A biometric authentication device 1 shown in FIG. 1 is a device that captures a vein image of a finger F and performs personal authentication, and includes a sensing unit 2, a storage unit 40, a control unit 50, and an output unit 60. The sensing unit 2 includes a cover glass 10, a light emitting unit 20, and a light receiving unit 30. The cover glass 10 is a glass protective cover that covers the imaging region. On the cover glass 10, a finger F (for example, an index finger of the right hand) of a person to be authenticated is placed. The light emitting unit 20 includes, for example, a light emitting layer formed of an organic EL (Electro Luminescent) material, an anode, and a cathode, and emits irradiation light IL for irradiating the finger F. The irradiation light IL is near infrared light having a wavelength of about 600 to 1200 nm, for example.

  Irradiation light IL (near infrared light) emitted from the light emitting unit 20 is irradiated on the finger F from the lower side of the cover glass 10 and scattered when reaching the inside of the finger F, and a part thereof is received as reflected light RL. Head toward the part 30 side. Reduced hemoglobin flowing through veins has the property of absorbing near infrared light. For this reason, when the finger F is imaged using an image sensor for near infrared light, the vein portion under the finger F appears darker than the surrounding tissue. The pattern due to this difference in brightness becomes a vein image. The light receiving unit 30 is an image sensor for near infrared light, and includes a plurality of light receiving elements arranged in a matrix. Each light receiving element converts incident light (reflected light RL from the finger F) into an electric signal (light receiving signal) having a signal level corresponding to the amount of light.

  Although specific structures of the light emitting unit 20 and the light receiving unit 30 will be described later, the light emitting unit 20 and the light receiving unit 30 are the same with respect to the finger F placed on the cover glass 10 as shown in FIG. Located on the side (lower side in the figure). Further, the light emitting unit 20 is located on the cover glass 10 side (upper side in the drawing) than the light receiving unit 30.

  The storage unit 40 is a non-volatile memory such as a flash memory or a hard disk, and stores a vein image of a finger F registered in advance (for example, the index finger of the right hand) as a master vein image for personal authentication. The control unit 50 includes a CPU (Central Processing Unit) and a RAM (Random Access Memory), and controls turning on and off of the light emitting unit 20. In addition, the control unit 50 reads a light reception signal from each light receiving element included in the light receiving unit 30, and generates a vein image of the finger F based on the read light reception signal for one frame (for the imaging region). Further, the control unit 50 collates the generated vein image with the master vein image registered in the storage unit 40 and performs personal authentication. For example, the control unit 50 compares the characteristics of two vein images to be collated (for example, the number and position of vein branches), and if the similarity is equal to or higher than a predetermined threshold, The person who puts the finger F on is authenticated as the person whose master vein image is registered in the storage unit 40. The output unit 60 is, for example, a display unit or a voice notification unit, and notifies the authentication result by display or voice.

FIG. 2 is a cross-sectional view of the sensing unit 2.
The sensing unit 2 is roughly classified into a sensor substrate 3 in which a plurality of light receiving elements D are arranged in a matrix on a substrate 31, and an anode 22 and a plurality of light shielding layers on the substrate 21 (the lower surface of the substrate 21 in the figure). A light emitting element substrate 4 in which a BM, a plurality of insulating layers 28, an organic EL layer 26, and a plurality of cathodes 24 are laminated, and a lens substrate 5 on which a lens array LA is formed on the substrate 10 (the lower surface of the substrate 10 in the figure). And divided. That is, the sensing unit 2 is manufactured by bonding these three substrates 3 to 5 together. A sealing layer 29 is interposed between the sensor substrate 3 and the light emitting element substrate 4. The substrate 10 corresponds to the cover glass 10 in FIG.

  Each light receiving element D disposed on the upper surface of the substrate 31 converts the reflected light RL (near infrared light) incident on the light receiving surface into a light receiving signal having a signal level corresponding to the light quantity. The light receiving element D may be, for example, a CCD (Charge Coupled Device) element, or may use CIGS (Copper Indium Gallium DiSelenide) or microcrystal silicon as a material for photoelectric conversion. As the substrate 31, a plate material that does not transmit near-infrared light, such as a ceramic substrate or a metal sheet, can be used in addition to a glass substrate or a quartz substrate that has high transparency to near-infrared light.

  On the lower surface of the substrate 10 (cover glass 10), a lens array LA is formed over the entire surface of the imaging region. The lens array LA is formed by arranging a plurality of microlenses ML in a matrix, and is formed of a material having high transmissivity to near-infrared light such as glass or quartz. The arrangement pitch of the microlenses ML is the same as the arrangement pitch of the light receiving elements D, and each microlens ML forms an image of the reflected light RL from the finger F on the light receiving surface of the light receiving element D located directly below.

The substrate 21 is a glass substrate or a quartz substrate, and an anode 22 is formed on the lower surface of the substrate 21 over the entire imaging region. The anode 22 is a film-like electrode (conductor) facing the plurality of cathodes 24 with the organic EL layer 26 interposed therebetween, and is formed of a material having high transparency to near infrared light and high conductivity. The Examples of the constituent material of the anode 22 include oxides such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and Al-containing ZnO, Au, Pt, Examples thereof include Ag, Cu, and alloys containing these. Two or more of these may be combined. Moreover, although the film thickness of the anode 22 is based also on material, it is preferable that it is about 10-200 nm, for example, and it is more preferable that it is about 50-150 nm.

  On the other hand, each of the plurality of cathodes 24 is a strip-shaped film body electrode (conductor) extending in the Y-axis direction, and adjacent cathodes 24 have a predetermined separation width in the X-axis direction. Each cathode 24 is formed of a material having a high light shielding property against near infrared light and a high conductivity. Examples of the constituent material of the cathode 24 include Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb, Cr, and alloys containing these. Can be mentioned. Two or more of these may be combined. In particular, Al, MgAg and the like are preferable. Further, the thickness of the cathode 24 needs to be at least a thickness that does not transmit near-infrared light, and depends on the material, but is preferably about 100 to 1000 nm, for example, about 100 to 500 nm. More preferably. The cathode 24 is patterned on the surface of the organic EL layer 26 (the lower surface of the organic EL layer 26 in the figure) by a mask vapor deposition method. In addition, the lower side of each cathode 24 and the separation region between the cathodes 24 are covered with a sealing layer 29 formed of a material that is highly transmissive to near infrared light. Examples of the constituent material of the sealing layer 29 include an inorganic material such as SiON in addition to an acrylic or epoxy resin material (organic material).

  A plurality of light shielding layers BM are provided on the lower surface of the anode 22. Each light shielding layer BM has a belt-like outer shape extending in the Y-axis direction. Each light shielding layer BM has a plurality of openings. The light shielding layer BM is formed of a material having high insulation properties and high light shielding properties with respect to near infrared light and low reflectance. Examples of the constituent material of the light shielding layer BM include Cr and TiN (titanium nitride). The light shielding layer BM is patterned on the surface of the anode 22 (the lower surface of the anode 22 in the figure) by a photolithography method. Therefore, the opening can be formed with high accuracy even if the size of the opening is extremely small.

  Each light shielding layer BM is covered with an insulating layer 28 for each light shielding layer BM. Each insulating layer 28 has a strip shape extending in the Y-axis direction. Further, as shown in the figure, the cross section of each insulating layer 28 is trapezoidal, and banks (slopes) are formed at both ends (X-axis direction) of each insulating layer 28 to prevent the organic EL layer 26 from being cut off. ing. The insulating layer 28 is formed of a material that is highly transmissive to near infrared light and has high insulating properties. Examples of the constituent material of the insulating layer 28 include acrylic resin. Since the insulating layer 28 can be patterned by a photolithography method, a bank can be formed with high accuracy. Further, since the light shielding layer BM and the insulating layer 28 are insulators, the anode 22 and the cathode 24 are partially insulated, and a non-light emitting region that does not emit near infrared light is formed in the organic EL layer 26.

  As shown in the figure, the space between the cathodes 24, the insulating layer 28, and the opening of the light shielding layer BM are located immediately above the light receiving surface of each light receiving element D. In other words, the plurality of cathodes 24 are formed so that the separated regions are located directly above the light receiving surfaces of the respective light receiving elements D. In addition, a plurality of light shielding layers BM and a plurality of insulating layers 28 are formed so that the openings are located immediately above the light receiving surfaces of the respective light receiving elements D. In addition, each opening causes the reflected light RL transmitted through the microlens ML positioned directly above to enter the light receiving surface of the light receiving element D positioned directly below.

The organic EL layer 26 is a light emitting layer formed of an organic EL material having a high transmittance with respect to near-infrared light, and is formed over the entire imaging region. The organic EL layer 26 emits near-infrared light by combining holes and electrons by supplying current. As a constituent material of the organic EL layer 26, for example, a dopant-lanthanide-based near infrared light emitting complex, porphyrin derivative, phthalocyanine derivative, pyran derivative, thiadiazole derivative, host-naphthacene derivative, quinoline derivative (Alq ₃ ), anthracene derivative, carbazole Derivatives and the like. The organic EL layer 26 emits light at the portion sandwiched between the anode 22 and the cathode 24. However, since the light shielding layer BM and the insulating layer 28 are insulators as described above, the portion where the light shielding layer BM and the insulating layer 28 are formed. The anode 22 and the cathode 24 are insulated. Therefore, the hatched portion in FIG. 2 (the portion directly sandwiched between the anode 22 and the cathode 24) is a light emitting region that emits near infrared light, and the other portions are non-light emitting regions. Thus, the organic EL layer 26 has a light emitting region and a non-light emitting region.

  Here, the cathode 24 and the light shielding layer BM have a function of shielding near infrared light. Further, since the light shielding layer BM and the insulating layer 28 are insulators, the portion corresponding to the separation region between the cathodes 24 in the organic EL layer 26 (that is, the portion corresponding to the light receiving surface of each light receiving element D) and its periphery. It can be a non-light emitting area. Further, the light shielding layer BM has a low reflectance with respect to near infrared light. Therefore, the cathode 24, the light shielding layer BM, and the insulating layer 28 suppress the irradiation light IL emitted from the organic EL layer 26 (light emitting region) from directly entering the light receiving surface of each light receiving element D through the separated region. be able to. In addition, when the non-light-emitting region of the organic EL layer 26 can be determined in this way, on the optical path of the reflected light RL incident on the light-receiving surface of each light-receiving element D (in FIG. (On a straight line extending in the direction), it is possible to exclude a light emitting region that emits the irradiation light IL having a larger light quantity than the reflected light RL. For this reason, the light receiving accuracy of the reflected light RL in each light receiving element D can be increased.

  Further, since the cathode 24 and the light shielding layer BM have a function of shielding near-infrared light, the reflected light incident obliquely from the adjacent microlens ML or the like as indicated by a broken line arrow in FIG. RL (so-called scattered light) can be shielded and crosstalk can be suppressed. Note that the crosstalk of the reflected light RL can be reduced by adjusting the size of the opening, the spacing between the cathodes 24, the thickness of the light shielding layer BM, the cathode 24, and the sealing layer 29, and the like. For example, the crosstalk can be reduced by reducing the size of the opening or the spacing between the cathodes 24, or increasing the thickness of the light shielding layer BM or the cathode 24. For this reason, the values of the size of the opening, the spacing between the cathodes 24, the thickness of the light shielding layer BM, the cathode 24, and the sealing layer 29 are determined so that crosstalk does not occur as much as possible.

FIG. 3 is an enlarged view of the insulating layer 28 shown in FIG.
On the surface of the anode 22 (on the organic EL layer 26 side), a light shielding layer BM having an opening is patterned by a photolithography method. In addition, the insulating layer 28 is patterned by photolithography so as to cover the light shielding layer BM. The surface of the insulating layer 28 that contacts the organic EL layer 26 includes a bank (slope) that is inclined with respect to the surface of the anode 22. In addition, the angle α formed between the surface of the insulating layer 28 in contact with the anode 22 and the bank is an acute angle (an angle smaller than a right angle). When the light shielding layer BM and the insulating layer 28 are stacked on the surface of the anode 22 and then the organic EL layer 26 is formed thereon, a step is generated by the light shielding layer BM and the insulating layer 28. However, since both sides of the step become gentle slopes due to the banks of the insulating layer 28, the organic EL layer 26 can be continuously formed over the entire surface of the imaging region without causing breaks. For this reason, it is possible to prevent a short circuit or a leak between the anode 22 and the cathode 24 due to the disconnection of the organic EL layer 26.

  It is conceivable to form the organic EL layer 26 directly on the light shielding layer BM without providing the insulating layer 28. However, in this case, the surroundings of the organic EL material are deteriorated, and it becomes difficult to laminate the organic EL material without any gap particularly in the opening or at the boundary with the light shielding layer BM. For this reason, the organic EL layer 26 may be locally thinned or the organic EL layer 26 may be cut off, causing a short circuit or a leak between the anode 22 and the cathode 24.

FIG. 4 is a plan view showing the arrangement of the cathode 24, the light shielding layer BM, the insulating layer 28, and the light receiving element D.
As shown in the figure, each cathode 24 has a strip shape extending in the Y-axis direction, and is provided apart from each other. Each light shielding layer BM has a belt-like outer shape extending in the Y-axis direction. Each light shielding layer BM has a plurality of openings along the Y-axis direction. Each insulating layer 28 has a strip shape extending in the Y-axis direction and covers the entire surface of the light shielding layer BM. When viewed in plan from the cover glass 10 side, the space between the cathodes 24 is covered by the light shielding layer BM and the insulating layer 28, and both ends (X-axis direction) of the light shielding layer BM and the insulating layer 28 overlap the adjacent cathodes 24. As shown in the figure, the arrangement pitch of the openings is the same as the arrangement pitch of the light receiving elements D, and the openings correspond to the light receiving elements D (light receiving surfaces) on a one-to-one basis. The shape of each opening is, for example, a square having a side length of about 5 to 20 μm, and one light receiving element D (light receiving surface) is included in each opening when viewed from the cover glass 10 side. . Thus, the cathode 24 and the light shielding layer BM cover portions other than the opening when viewed in plan from the cover glass 10 side, and function as a light receiving window of each light receiving element D.

  In addition, the hatched portion (the central portion of each cathode 24) in the drawing corresponds to the light emitting region of the organic EL layer 26. That is, the light emitting region of the organic EL layer 26 is formed in a stripe shape over the entire surface of the imaging region when viewed in plan from the cover glass 10 side. Therefore, the finger F can be irradiated with near-infrared light (irradiation light IR) of uniform intensity, and there is no unevenness in the amount of light for each light receiving element D.

FIG. 5 is a schematic diagram showing the arrangement of each layer when focusing on one light receiving element D. FIG.
In the figure, the light receiving surface of the light receiving element D located at the lowermost layer has a circular shape. Further, two cathodes 24 extending in the Y-axis direction are positioned on both sides (left and right in the drawing) with the light receiving surface of the light receiving element D interposed therebetween. On the other hand, the uppermost layer is provided with the anode 22 over the entire surface, and the light shielding layer BM extending in the Y-axis direction is positioned below the anode 22. When the separation width between the two cathodes 24 is W1, the width W2 in the X-axis direction of the light shielding layer BM is larger than W1. The light shielding layer BM has a square opening larger than the light receiving surface at a position corresponding to the light receiving surface of the light receiving element D. Parts other than the opening are shielded from light by the cathode 24 and the light shielding layer BM. An insulating layer 28 extending in the Y-axis direction is located under the light shielding layer BM. The insulating layer 28 has a width W3 in the X-axis direction larger than the width W2 of the light shielding layer BM, and covers the entire surface of the light shielding layer BM. An organic EL layer 26 is provided under the insulating layer 28 over the entire surface. Since the light-shielding layer BM and the insulating layer 28 are insulators, both side portions of the organic EL layer 26 indicated by hatching in the drawing are light emitting regions and the inner portions thereof are non-light emitting regions.

FIG. 6 is a diagram illustrating a circuit configuration of the light emitting unit 20.
As shown in the figure, the light emitting unit 20 is provided with a cathode drive circuit 200. The cathode drive circuit 200 selects one or more cathodes 24 that supply current from the _n cathodes 24 _{1 to} 24 _n based on the clock signal and the control signal supplied from the control unit 50. A current is supplied between the one or more cathodes 24 selected by the cathode driving circuit 200 and the anode 22, and the organic EL layer 26 emits light. For example, when the cathode drive circuit 200 selects all the cathodes 24 _{1 to} 24 _n at the same time, portions of the organic EL layer 26 corresponding to all the cathodes 24 _{1 to} 24 _n emit light at the same time. In this case, the entire surface of the imaging region emits light in a stripe shape. Also, when the cathode driving circuit 200 selects the cathode ₂₄ 1-24 ₄ simultaneously, only the portion corresponding to the cathode ₂₄ 1-24 ₄ in the organic EL layer 26 emits light simultaneously. When the cathode driving circuit 200 sequentially selects the cathodes 24 _{1 to} 24 _n one by one, portions of the organic EL layer 26 corresponding to the cathode 24 selected by the cathode driving circuit 200 emit light sequentially.

Note that the cathode drive circuit 200 is not required if only the portions corresponding to all the cathodes 24 _{1 to} 24 _n in the organic EL layer 26 are allowed to emit light at the same time. In this case, the control unit 50 may supply current between all the cathodes 24 _{1 to} 24 _n and the anode 22 to light up the organic EL layer 26 at the timing when the light emitting unit 20 is turned on.

Next, the operation of the biometric authentication device 1 will be described.
When the control unit 50 detects that the finger F is placed on the cover glass 10 using a contact sensor (not shown) or the like, the control unit 50 supplies current between the anode 22 and the one or more cathodes 24, and organically The EL layer 26 is caused to emit light. For example, the control unit 50 controls the cathode driving circuit 200 to select all the cathodes 24 _{1 to} 24 _n at the same time, and simultaneously emits portions corresponding to all the cathodes 24 _{1 to} 24 _n in the organic EL layer 26. Let Irradiation light IL (near-infrared light) emitted from the organic EL layer 26 (light emitting region) is applied to the finger F through the anode 22, the substrate 21, the lens array LA, and the cover glass 10, and is applied to the inside of the finger F. When it reaches, it scatters, and a part thereof is reflected light RL toward the light receiving unit 30 side. Further, a part of the reflected light RL from the finger F is a separation region between the cover glass 10, the lens array LA, the substrate 21, the anode 22, the opening of the light shielding layer BM, the insulating layer 28, the organic EL layer 26, and the cathode 24. The light is incident on the light receiving surface of the light receiving element D through the sealing layer 29. Each light receiving element D converts the reflected light RL incident on the light receiving surface into a light receiving signal having a signal level corresponding to the amount of light. The control unit 50 reads a light reception signal from each light receiving element D, and generates a vein image of the finger F based on the read light reception signal for one frame. Further, the control unit 50 collates the generated vein image with the master vein image registered in the storage unit 40 to perform personal authentication, and outputs an authentication result from the output unit 60.

  As described above, according to the present embodiment, the cathode 24 and the light shielding layer BM have a function of shielding near infrared light. Further, the light shielding layer BM and the insulating layer 28, which are insulators, cover the portion corresponding to the separation region between the cathodes 24 in the organic EL layer 26 (that is, the portion corresponding to the light receiving surface of each light receiving element D) and its periphery. Set to light emitting area. Further, the light shielding layer BM has a low reflectance with respect to near infrared light. Therefore, it is possible to suppress the irradiation light IL emitted from the organic EL layer 26 (light emitting region) from directly entering the light receiving surface of each light receiving element D through the separated region. Further, since the cathode 24 and the light shielding layer BM shield light from portions other than the light receiving window (opening) when viewed in plan from the cover glass 10 side, the reflected light RL (scattering light) incident obliquely from the adjacent microlens ML or the like. Light) can be prevented from entering the light receiving surface of each light receiving element D. Further, since the light shielding layer BM is provided between the anode 22 and the cathode 24 (in the light emitting unit 20), as described in Patent Document 1, the light source unit 111 (light emitting unit) and the detection element 113 (light receiving unit). There is no need to interpose a glass substrate 125 on which a light shielding layer 126 is formed. Therefore, the biometric authentication device 1 (sensing unit 2) is suppressed while suppressing direct light from the organic EL layer 26 or scattered light incident obliquely from the adjacent microlens ML or the like from entering the light receiving surface of each light receiving element D. ) In the Z-axis direction can be reduced. Further, since the cathode 24 and the light shielding layer BM are formed on one substrate (the light emitting element substrate 4), the positional deviation between the cathode 24 and the light shielding layer BM due to the bonding of the substrates does not occur.

  Further, according to the present embodiment, the light shielding layer BM provided on the surface of the anode 22 (on the organic EL layer 26 side) is covered with the insulating layer 28. In the insulating layer 28, the surface in contact with the organic EL layer 26 includes an inclined surface (bank) inclined with respect to the surface of the anode 22, and the angle α formed by this inclined surface and the surface in contact with the anode 22 is an acute angle. Therefore, since the organic EL layer 26 can be formed without causing breakage, a short circuit or leakage between the anode 22 and the cathode 24 can be prevented.

  Further, according to the present embodiment, the light shielding layer BM and the insulating layer 28 which are insulators make the portion corresponding to the separation region between the cathodes 24 in the organic EL layer 26 and the periphery thereof a non-light emitting region. For this reason, it is possible to exclude a light emitting region that emits the irradiation light IL having a light amount larger than that of the reflected light RL from the optical path of the reflected light RL incident on the light receiving surface of each light receiving element D. Therefore, the light receiving accuracy of the reflected light RL in each light receiving element D can be increased, and the imaging accuracy of the vein image can be improved.

  Further, according to the present embodiment, the cathode 24 can be line-driven by the cathode driving circuit 200. Therefore, for example, only the part corresponding to some of the cathodes 24 in the imaging area can emit light, and the emission range of the irradiation light IL can be limited to a part. Further, it is possible to simultaneously emit light corresponding to all the cathodes 24 in the imaging region, or to sequentially select the cathodes 24 one by one and sequentially emit light corresponding to the selected cathodes 24.

  Further, according to the present embodiment, the light emitting region of the organic EL layer 26 becomes a portion indicated by hatching in FIG. 4 when viewed from the cover glass 10 side. Therefore, the finger F can be irradiated with near-infrared light having a uniform intensity, and there is no unevenness in the amount of light for each light receiving element D. Further, according to the present embodiment, since the organic EL layer 26 may be formed on the entire surface of the imaging region, patterning of the organic EL layer 26 is unnecessary, and the yield in the manufacturing process can be reduced. Further, as shown in FIG. 7, for example, when the organic EL layer 26 and the cathode 24 are formed for each pixel, a leak may occur between the anode 22 and the cathode 24 at a portion indicated by a broken line in the drawing. According to this embodiment, such a leak can also be suppressed.

  It is conceivable to eliminate the light shielding layer BM and form the light receiving window with only the cathode. In this case, for example, a cathode having an outer shape corresponding to the imaging region and having an opening formed at a position corresponding to the light receiving surface of each light receiving element D may be used. However, the cathode needs to be patterned on the surface of the organic EL layer 26 (the lower surface of the organic EL layer 26 in FIG. 2). Patterning by the photolithography method on the organic EL layer 26 is generally performed by a mask vapor deposition method because the organic EL layer 26 is damaged. However, in the case of the mask vapor deposition method, if the size of the opening is small, it is difficult to form the opening with high accuracy, resulting in an increase in yield in the manufacturing process and an increase in manufacturing cost. On the other hand, according to the present embodiment, the cathode 24 and the light shielding layer BM are overlapped to form a light receiving window, and the cathode 24 and the light shielding layer BM need to be produced in order to form the light receiving window. Since the layer BM (opening) is patterned by the photolithography method, a sufficiently high-accuracy light receiving window can be formed for the cathode 24 (spaced region) even by the mask vapor deposition method. For this reason, compared with the case where the light receiving window is formed only by the cathode, it is possible to form the light receiving window with high accuracy without increasing the yield in the manufacturing process and increasing the manufacturing cost.

<2. Modification>
The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible. Also, two or more of the following modifications can be combined as appropriate.

[Modification 1]
The arrangement pattern of the light receiving elements D is not limited to a matrix. For example, the light receiving elements D may be arranged so as to form a black or white array pattern in a chess pattern (checkered pattern). The same applies to the arrangement pattern of the openings. Further, the present invention may be applied to a sweep-type biometric authentication device. In this case, as shown in FIG. 8, the light receiving elements D and the openings need only be arranged in a line along the X-axis direction. Each light shielding layer BM is provided with only one opening.

[Modification 2]
The light-shielding layer BM only needs to have at least a function of shielding near-infrared light, and is not necessarily formed of a highly insulating material or a material with low reflectivity for near-infrared light. However, if the light shielding layer BM is made of an insulator, the thickness of the portion where the light shielding layer BM and the insulating layer 28 are stacked can be made thinner than when the light shielding layer BM is not an insulator. In addition, the light shielding layer BM does not necessarily have openings provided at positions corresponding to all the light receiving elements D (light receiving surfaces). For example, in order to correct the change in the photoelectric conversion characteristics of the light receiving element D due to the amount of received light (integrated amount), or to obtain the value of the received light signal in a state where no reflected light RL is incident as a reference value, A light receiving element D in which the upper side of the light receiving surface is completely covered with the light shielding layer BM may be provided at the end or the like. Further, it is sufficient that at least two cathodes 24 are provided, and at least one light receiving element D, light shielding layer BM, opening, and insulating layer 28 may be provided.

[Modification 3]
The shape of the light receiving surface of the light receiving element D is not limited to a circle, and may be any shape such as a rectangle or a hexagon. The shape of the opening of the light shielding layer BM is not limited to a square but may be an arbitrary shape. The size of the light receiving surface and the size of the opening may be the same, or the light receiving surface may be larger than the opening. Further, when viewed in plan from the cover glass 10 side, it is desirable that the center (or the center of gravity) of the light receiving surface is located in the opening, but at least a part of the light receiving surface may be located in the opening.

[Modification 4]
As the light emitting layer, in addition to the organic EL layer 26, a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer may be included. Examples of the constituent material for the hole transport layer and the hole injection layer include tetraarylbenzidine derivatives and tetraaryldiaminofluorene compounds. Examples of the constituent material of the electron transport layer include quinoline derivatives, oxadiazole derivatives, perylene derivatives, pyridine derivatives, pyrimidine derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives, azaindolizine derivatives, and the like. . Examples of the constituent material of the electron injection layer include alkali metal chalcogenides (oxides, sulfides, selenides, tellurides), alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides. And two or more of these may be combined. In addition, about the constituent material of the electron injection layer mentioned above, at least one element of Li, Na, Ba, Ca, Sr, Yb, Al, Ga, In, Cd, Mg, Si, Ta, Sb, and Zn is used. It may be an oxide, a nitride, an oxynitride, or the like, and two or more of these may be combined. Further, the light emitting layer may be formed using an inorganic EL material or a light emitting polymer instead of the organic EL material. Further, the light emitting layer may be a voltage driven type that emits light by application of a voltage. Further, the polarity of the anode 22 and the cathode 24 may be reversed.

[Modification 5]
The part of the living body subject to vein authentication may be the palm, the back of the hand, the eye, or the like. Further, a band pass filter (optical filter) that blocks light other than near infrared light may be provided. For example, the band pass filter can be provided between the substrate 21 and the anode 22 or between the cover glass 10 and the lens array LA. In addition, the present invention can be applied to a biometric authentication device that uses visible light instead of near infrared light and performs biometric authentication based on fingerprints and irises. In this case, the light emitting unit 20 (organic EL layer 26) emits visible light as the irradiation light IL. In addition, the light receiving unit 30 (each light receiving element D) receives visible light as the reflected light RL. The cover glass 10, the lens array LA, the substrate 21, the anode 22, the insulating layer 28, the organic EL layer 26, and the sealing layer 29 are formed of a material that is highly transmissive to visible light, and the cathode 24 and the light shielding layer. The BM is formed of a material having a high light blocking property with respect to visible light.

[Modification 6]
For example, the present invention can be applied to a personal computer or a mobile phone having a biometric authentication function. Further, the present invention can also be applied to an image reading apparatus such as an image scanner, a copying machine, a facsimile, or a barcode reader. Note that when the present invention is applied to an image reading apparatus, visible light is used instead of near-infrared light as the irradiation light IL and the reflected light RL.

DESCRIPTION OF SYMBOLS 1 ... Biometric authentication apparatus, 2 ... Sensing unit, 3 ... Sensor substrate, 4 ... Light emitting element substrate, 5 ... Lens substrate, 10 ... Cover glass / board | substrate, 20 ... Light emission part, 30 ... Light-receiving part, 40 ... Memory | storage part, 50 ... control unit, 60 ... output unit, F ... finger, IL ... irradiation light, RL ... reflected light, BM ... light blocking layer, D ... light-receiving element, 21 ... substrate, 22 ... anode, 24, 24 ₁ to 24 n _... cathode , 26 ... organic EL layer, 28 ... insulating layer, 29 ... sealing layer, 31 ... substrate, LA ... lens array, ML ... microlens, 200 ... cathode drive circuit.

Claims (7)

In a sensing device comprising a light emitting part, a light receiving part, a light shielding layer and an insulating layer, irradiating light on the object from the light emitting part, and receiving light reflected from the object by the light receiving part,
The light emitting unit and the light receiving unit are provided on the same side with respect to the object, the light emitting unit is located on the object side from the light receiving unit,
The light emitting unit
A light emitting layer that emits irradiation light to irradiate the object;
A first electrode located on the object side of the light emitting layer and transmitting the irradiation light and the reflected light;
A second electrode and a third electrode, which are located closer to the light receiving part than the light emitting layer, shield the irradiation light and the reflected light, and are provided apart from each other;
The light receiving unit is
A light receiving element for receiving the reflected light;
The light shielding layer is
Provided at a position corresponding to a separation region between the second electrode and the third electrode on the light emitting layer side surface of the first electrode to shield the irradiation light and the reflected light and to form an opening. ,
The insulating layer is
An insulator that is provided at a position corresponding to the separation region, covers the light shielding layer and transmits the irradiation light and the reflected light;
When viewed in plan from the object side, the light shielding layer and the insulating layer overlap the separation region, and the light receiving surface of the light receiving element is located in the opening,
In the insulating layer, the surface in contact with the light emitting layer includes an inclined surface inclined with respect to the surface of the first electrode, and an angle formed by the inclined surface and the surface in contact with the first electrode is an acute angle. Sensing device. In a sensing device comprising a light emitting unit, a light receiving unit, a plurality of light shielding layers and a plurality of insulating layers, irradiating light on the object from the light emitting unit, and receiving light reflected from the object by the light receiving unit,
The light emitting unit and the light receiving unit are provided on the same side with respect to the object, the light emitting unit is located on the object side from the light receiving unit,
The light emitting unit
A light emitting layer that emits irradiation light to irradiate the object;
A first electrode located on the object side of the light emitting layer and transmitting the irradiation light and the reflected light;
A plurality of second electrodes that are located closer to the light receiving part than the light emitting layer, shield the irradiation light and the reflected light, and are provided apart from each other;
The light receiving unit is
A plurality of light receiving elements for receiving the reflected light;
Each of the plurality of light shielding layers is
The first electrode is provided at a position corresponding to each of the separated regions existing between the adjacent second electrodes on the light emitting layer side surface of the first electrode, and shields the irradiation light and the reflected light and includes at least one An opening is formed,
Each of the plurality of insulating layers is
An insulator that is provided at a position corresponding to each of the separation regions, covers the light shielding layer, and transmits the irradiation light and the reflected light;
When viewed in plan from the object side, each of the separation regions overlaps the light shielding layer and the insulating layer, and one light receiving surface of the light receiving element is located in each opening,
In each of the plurality of insulating layers, a surface in contact with the light emitting layer includes an inclined surface inclined with respect to the surface of the first electrode, and an angle formed by the inclined surface and the surface in contact with the first electrode is an acute angle. Sensing device characterized by. The sensing device according to claim 1, wherein the light shielding layer is an insulator. The drive circuit which selects one or several said 2nd electrode as an object which supplies the drive signal for making the said light emitting layer light-emit among these several 2nd electrodes is provided. The Claim 2 or 3 characterized by the above-mentioned. Sensing device. The sensing device according to any one of claims 1 to 4, wherein the light emitting layer is formed over an entire imaging region for imaging the object. The sensing device according to any one of claims 1 to 5, wherein the light emitting layer emits near infrared light. An electronic apparatus comprising the sensing device according to any one of claims 1 to 6.

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