Detection device

Abstract

To provide a detection device capable of improving detection accuracy.SOLUTION: A detection device includes a substrate, a photodiode provided on the substrate, a lens provided so as to overlap the photodiode, a light-shielding layer provided between the photodiode and the lens and having an opening in a region overlapping with the photodiode, and a light-transmitting resin layer and a buffer layer laminated between the light-shielding layer and the lens, and the lens is provided directly on and in contact with the buffer layer. The buffer layer is made of a resin material containing a material different from that of the light-transmitting resin layer.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a detection device. [Background technology]

[0002] Patent Document 1 describes a detection device having a plurality of photodiodes, a light-transmitting resin layer covering the plurality of photodiodes, and a plurality of lenses provided so as to overlap the plurality of photodiodes, respectively. The plurality of lenses are provided directly on the light-transmitting resin layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-84273 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such a detection device, if there is variation in the shape of the lens, the state of the light that passes through the lens and is focused on the photodiode will differ, which may result in a decrease in detection accuracy. For this reason, it is necessary to suppress the variation in the shape of the lens in the detection device.

[0005] An object of the present invention is to provide a detection device capable of improving detection accuracy. [Means for solving the problem]

[0006] A detection device of one embodiment of the present invention includes a substrate, a photodiode provided on the substrate, a lens overlapping the photodiode, a light-shielding layer provided between the photodiode and the lens and having an opening in an area overlapping with the photodiode, and a light-transmitting resin layer and a buffer layer stacked between the light-shielding layer and the lens, and the lens is provided in direct contact with the buffer layer. [Brief description of the drawings]

[0007] [Figure 1A] FIG. 1A is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to an embodiment. [Figure 1B] FIG. 1B is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to Modification 1. As shown in FIG. [Figure 1C] FIG. 1C is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to Modification 2. As shown in FIG. [Figure 1D] FIG. 1D is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to Modification 3. As shown in FIG. [Diagram 2] FIG. 2 is a plan view showing the detection device according to the embodiment. [Diagram 3] FIG. 3 is a block diagram illustrating an example of the configuration of the detection device according to the embodiment. [Figure 4] FIG. 4 is a circuit diagram showing a detection element. [Diagram 5] FIG. 5 is a plan view showing an optical filter according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI' of FIG. [Figure 7] FIG. 7 is an explanatory diagram that illustrates a cross-sectional configuration of a lens according to an embodiment. [Figure 8] FIG. 8 is an explanatory diagram that illustrates a cross-sectional configuration of a lens according to a comparative example. [Figure 9] FIG. 9 is a table showing the measurement results of the lens according to the example and the lens structure according to the comparative example. [Figure 10] FIG. 10 is a plan view that illustrates a photodiode of the detection device according to the embodiment. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI' of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present disclosure is not limited by the contents described in the following embodiments. The components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the components described below can be appropriately combined. Note that the disclosure is merely an example, and those that a person skilled in the art can easily imagine appropriate modifications while maintaining the gist of the present disclosure are naturally included in the scope of the present disclosure. In addition, in order to make the explanation clearer, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment, but they are merely examples and do not limit the interpretation of the present disclosure. In addition, in this disclosure and each figure, elements similar to those described above with respect to the previously mentioned figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0009] In this specification and the claims, when expressing an aspect of arranging another structure on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both a case in which another structure is arranged directly on top of a certain structure so as to be in contact with the certain structure, and a case in which another structure is arranged above a certain structure via yet another structure.

[0010] (Embodiment) Fig. 1A is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to an embodiment. Fig. 1B is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a first modified example. Fig. 1C is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a second modified example. Fig. 1D is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a third modified example.

[0011] As shown in FIG. 1A, the detection device 1 includes an array substrate 2 (photodiode 30), an optical filter 7, an adhesive layer 125, and an illumination device 121 (cover member 122). That is, in a direction perpendicular to the surface of the array substrate 2, the array substrate 2 (photodiode 30), the optical filter 7, the adhesive layer 125, and the cover member 122 are laminated in this order. As will be described later, the cover member 122 can be replaced with the illumination device 121. The adhesive layer 125 only needs to bond the optical filter 7 and the cover member 122 together, and the structure may be such that the adhesive layer 125 is not provided in the region corresponding to the detection area AA. When the adhesive layer 125 is not provided in the detection area AA, the structure is such that the adhesive layer 125 bonds the cover member 122 and the optical filter 7 together in the region corresponding to the peripheral area GA outside the detection area AA. The adhesive layer 125 provided in the detection area AA may simply be referred to as a protective layer for the optical filter 7.

[0012] 1A, the illumination device 121 may be, for example, a so-called side-light type front light that uses a cover member 122 as a light guide plate provided at a position corresponding to the detection area AA of the detection device 1 and has a plurality of light sources 123 arranged at one end or both ends of the cover member 122. That is, the cover member 122 has a light irradiation surface 121a that emits light, and is one component of the illumination device 121. According to this illumination device 121, light L1 is irradiated from the light irradiation surface 121a of the cover member 122 toward a finger Fg that is a detection target. As the light source 123, for example, a light emitting diode (LED) that emits light of a predetermined color is used.

[0013] Furthermore, as shown in FIG. 1B, the illumination device 121 may have a light source (e.g., an LED) provided directly below the detection area AA of the detection device 1, and the illumination device 121 equipped with a light source also functions as a cover member 122.

[0014] Furthermore, the lighting device 121 is not limited to the example of FIG. 1B, and may be provided to the side or above the cover member 122 as shown in FIG. 1C, and light L1 may be irradiated onto the finger Fg from the side or above the finger Fg.

[0015] Furthermore, as shown in FIG. 1D, the illumination device 121 may be a so-called direct type backlight having a light source (for example, an LED) provided in the detection area AA of the detection device 1.

[0016] Light L1 emitted from the lighting device 121 is reflected as light L2 by a finger Fg, which is a detection target. The detection device 1 detects the light L2 reflected by the finger Fg to detect unevenness (e.g., a fingerprint) on the surface of the finger Fg. Furthermore, in addition to detecting a fingerprint, the detection device 1 may detect information about a living body by detecting the light L2 reflected inside the finger Fg. The information about a living body may be, for example, an image of blood vessels such as veins, a pulse rate, a pulse wave, etc. The color of the light L1 from the lighting device 121 may be different depending on the detection target.

[0017] The cover member 122 is a member for protecting the array substrate 2 and the optical filter 7, and covers the array substrate 2 and the optical filter 7. As described above, the illumination device 121 may also serve as the cover member 122. In a structure in which the cover member 122 is separated from the illumination device 121 as shown in FIGS. 1C and 1D, the cover member 122 is, for example, a glass substrate. Note that the cover member 122 is not limited to a glass substrate, and may be a resin substrate or the like. Also, the cover member 122 may not be provided. In this case, a protective layer such as an insulating film is provided on the surfaces of the array substrate 2 and the optical filter 7, and the finger Fg comes into contact with the protective layer of the detection device 1.

[0018] 1B, a display panel may be provided instead of the illumination device 121. The display panel may be, for example, an organic EL display panel (OLED: Organic Light Emitting Diode) or an inorganic EL display (micro LED, mini LED). Alternatively, the display panel may be a liquid crystal display panel (LCD: Liquid Crystal Display) using liquid crystal elements as display elements, or an electrophoretic display panel (EPD: Electrophoretic Display) using electrophoretic elements as display elements. Even in this case, it is possible to detect information about the fingerprint and biometric information of the finger Fg based on the light L2 that is obtained by reflecting display light (light L1) emitted from the display panel by the finger Fg.

[0019] FIG. 2 is a plan view showing a detection device according to an embodiment. The first direction Dx shown in FIG. 2 and subsequent figures is a direction in a plane parallel to the substrate 21. The second direction Dy is a direction in a plane parallel to the substrate 21, and is a direction perpendicular to the first direction Dx. The second direction Dy may not be perpendicular to the first direction Dx but may intersect with it. The third direction Dz is a direction perpendicular to the first direction Dx and the second direction Dy, and is a normal direction to the substrate 21. Moreover, "plan view" refers to the positional relationship when viewed from the third direction Dz.

[0020] As shown in FIG. 2, the detection device 1 includes an array substrate 2 (substrate 21), a sensor unit 10, a scanning line driving circuit 15, a signal line selection circuit 16, a detection circuit 48, a control circuit 102, and a power supply circuit 103.

[0021] The control board 101 is electrically connected to the board 21 via the wiring board 110. The wiring board 110 is, for example, a flexible printed circuit board or a rigid board. The wiring board 110 is provided with a detection circuit 48. The control board 101 is provided with a control circuit 102 and a power supply circuit 103. The control circuit 102 is, for example, an FPGA (Field Programmable Gate Array). The control circuit 102 supplies control signals to the sensor unit 10, the scanning line driving circuit 15, and the signal line selection circuit 16 to control the operation of the sensor unit 10. The power supply circuit 103 supplies voltage signals such as a power supply potential VDD and a reference potential VCOM (see FIG. 4) to the sensor unit 10, the scanning line driving circuit 15, and the signal line selection circuit 16. In the present embodiment, the case where the detection circuit 48 is disposed on the wiring board 110 is illustrated, but is not limited to this. The detection circuit 48 may be disposed on the board 21.

[0022] The substrate 21 has a detection area AA and a peripheral area GA. The detection area AA and the peripheral area GA extend in a plane direction parallel to the substrate 21. Within the detection area AA, each element (detection element 3) of the sensor unit 10 is provided. The peripheral area GA is an area outside the detection area AA, and is an area where each element (detection element 3) is not provided. In other words, the peripheral area GA is an area between the outer periphery of the detection area AA and the end of the substrate 21. Within the peripheral area GA, a scanning line driving circuit 15 and a signal line selection circuit 16 are provided. The scanning line driving circuit 15 is provided in an area of ​​the peripheral area GA extending along the second direction Dy. The signal line selection circuit 16 is provided in an area of ​​the peripheral area GA extending along the first direction Dx, and is provided between the sensor unit 10 and the detection circuit 48.

[0023] Each of the detection elements 3 of the sensor unit 10 is an optical sensor having a photodiode 30 as a sensor element. The photodiode 30 is a photoelectric conversion element, and outputs an electrical signal according to the light irradiated thereto. More specifically, the photodiode 30 is a PIN (Positive Intrinsic Negative) photodiode. The photodiode 30 may also be an OPD (Organic Photo Diode). The detection elements 3 are arranged in a matrix in the detection area AA. The photodiodes 30 of the detection elements 3 perform detection according to gate drive signals (e.g., a reset control signal RST and a read control signal RD) supplied from the scanning line drive circuit 15. The photodiodes 30 output an electrical signal according to the light irradiated thereto as a detection signal Vdet to the signal line selection circuit 16. The detection device 1 detects information about a living body based on the detection signals Vdet from the photodiodes 30.

[0024] Fig. 3 is a block diagram showing a configuration example of a detection device according to an embodiment. As shown in Fig. 3, the detection device 1 further includes a detection control circuit 11 and a detection unit 40. A part or all of the functions of the detection control circuit 11 are included in a control circuit 102. In addition, a part or all of the functions of the detection unit 40 other than the detection circuit 48 are included in the control circuit 102.

[0025] The detection control circuit 11 is a circuit that supplies control signals to the scanning line driving circuit 15, the signal line selection circuit 16, and the detection unit 40, respectively, and controls their operations. The detection control circuit 11 supplies various control signals, such as a start signal STV and a clock signal CK, to the scanning line driving circuit 15. The detection control circuit 11 also supplies various control signals, such as a selection signal ASW, to the signal line selection circuit 16.

[0026] The scanning line driving circuit 15 is a circuit that drives a plurality of scanning lines (readout control scanning line GLrd, reset control scanning line GLrst (see FIG. 4)) based on various control signals. The scanning line driving circuit 15 sequentially or simultaneously selects a plurality of scanning lines, and supplies gate driving signals (e.g., reset control signal RST, readout control signal RD) to the selected scanning lines. In this way, the scanning line driving circuit 15 selects a plurality of photodiodes 30 connected to the scanning lines.

[0027] The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects a plurality of output signal lines SL (see FIG. 4). The signal line selection circuit 16 is, for example, a multiplexer. The signal line selection circuit 16 connects the selected output signal line SL to the detection circuit 48 based on a selection signal ASW supplied from the detection control circuit 11. As a result, the signal line selection circuit 16 outputs the detection signal Vdet of the photodiode 30 to the detection unit 40.

[0028] The detection unit 40 includes a detection circuit 48, a signal processing circuit 44, a coordinate extraction circuit 45, a memory circuit 46, and a detection timing control circuit 47. Based on a control signal supplied from the detection control circuit 11, the detection timing control circuit 47 controls the detection circuit 48, the signal processing circuit 44, and the coordinate extraction circuit 45 so that they operate in synchronization with each other.

[0029] The detection circuit 48 is, for example, an analog front-end circuit (AFE). The detection circuit 48 is a signal processing circuit having at least the functions of a detection signal amplifier circuit 42 and an A / D conversion circuit 43. The detection signal amplifier circuit 42 is a circuit that amplifies the detection signal Vdet, and is, for example, an integration circuit. The A / D conversion circuit 43 converts the analog signal output from the detection signal amplifier circuit 42 into a digital signal.

[0030] The signal processing circuit 44 is a logic circuit that detects a predetermined physical quantity input to the sensor unit 10 based on an output signal from the detection circuit 48. When the finger Fg is in contact with or close to the detection surface, the signal processing circuit 44 can detect unevenness on the surface of the finger Fg or the palm based on a signal from the detection circuit 48. The signal processing circuit 44 may also detect information about the living body based on the signal from the detection circuit 48. The information about the living body is, for example, a blood vessel image of the finger Fg or the palm, a pulse wave, a pulse rate, blood oxygen saturation, etc.

[0031] The memory circuit 46 temporarily stores the signal calculated by the signal processing circuit 44. The memory circuit 46 may be, for example, a RAM (Random Access Memory), a register circuit, or the like.

[0032] The coordinate extraction circuit 45 is a logic circuit that determines the detection coordinates of the unevenness of the surface of the finger Fg, etc., when the contact or proximity of the finger Fg is detected in the signal processing circuit 44. The coordinate extraction circuit 45 is also a logic circuit that determines the detection coordinates of the blood vessels of the finger Fg or the palm. The coordinate extraction circuit 45 combines the detection signals Vdet output from each detection element 3 of the sensor unit 10 to generate two-dimensional information indicating the shape of the unevenness of the surface of the finger Fg, etc. The coordinate extraction circuit 45 may output the detection signal Vdet as the sensor output Vo without calculating the detection coordinates.

[0033] Next, an example of the circuit configuration of the detection device 1 will be described. Fig. 4 is a circuit diagram showing a detection element. As shown in Fig. 4, the detection element 3 has a photodiode 30, a reset transistor Mrst, a readout transistor Mrd, and a source follower transistor Msf. The reset transistor Mrst, the readout transistor Mrd, and the source follower transistor Msf are provided corresponding to one photodiode 30. The reset transistor Mrst, the readout transistor Mrd, and the source follower transistor Msf are each composed of an n-type TFT (Thin Film Transistor). However, this is not limited thereto, and each transistor may be composed of a p-type TFT.

[0034] A reference potential VCOM is applied to the anode of the photodiode 30. The cathode of the photodiode 30 is connected to a node N1. The node N1 is connected to a capacitance element Cs, one of the source or drain of the reset transistor Mrst, and the gate of the source follower transistor Msf. Furthermore, a parasitic capacitance Cp exists at the node N1. When light is incident on the photodiode 30, a signal (charge) output from the photodiode 30 is accumulated in the capacitance element Cs. Here, the capacitance element Cs is, for example, a capacitance formed between an upper electrode 34 and a lower electrode 35 (see FIG. 11) connected to the photodiode 30. The parasitic capacitance Cp is a capacitance added to the capacitance element Cs, and is a capacitance formed between various wirings and electrodes provided on the array substrate 2.

[0035] The gate of the reset transistor Mrst is connected to a reset control scanning line GLrst. The other of the source or drain of the reset transistor Mrst is supplied with a reset potential Vrst. When the reset transistor Mrst is turned on (conductive state) in response to a reset control signal RST, the potential of the node N1 is reset to the reset potential Vrst. The reference potential VCOM has a potential lower than the reset potential Vrst, and the photodiode 30 is reverse-bias driven.

[0036] The source follower transistor Msf is connected between a terminal to which a power supply potential VDD is supplied and the readout transistor Mrd (node ​​N2). The gate of the source follower transistor Msf is connected to the node N1. A signal (charge) generated in the photodiode 30 is supplied to the gate of the source follower transistor Msf. As a result, the source follower transistor Msf outputs a voltage signal corresponding to the signal (charge) generated in the photodiode 30 to the readout transistor Mrd.

[0037] The read transistor Mrd is connected between the source of the source follower transistor Msf (node ​​N2) and the output signal line SL (node ​​N3). The gate of the read transistor Mrd is connected to the read control scanning line GLrd. When the read transistor Mrd is turned on in response to the read control signal RD, the signal output from the source follower transistor Msf, i.e., a voltage signal corresponding to the signal (charge) generated in the photodiode 30, is output to the output signal line SL as the detection signal Vdet.

[0038] In the example shown in FIG. 4, the reset transistor Mrst and the readout transistor Mrd each have a so-called double-gate structure in which two transistors are connected in series. However, without being limited thereto, the reset transistor Mrst and the readout transistor Mrd may have a single-gate structure or a multi-gate structure in which three or more transistors are connected in series. Furthermore, the circuit of one detection element 3 is not limited to a configuration having three transistors, namely, the reset transistor Mrst, the source follower transistor Msf, and the readout transistor Mrd. The detection element 3 may have two or four or more transistors.

[0039] Next, detailed configurations of the detection element 3 and the optical filter 7 will be described. Fig. 5 is a plan view showing the optical filter according to the embodiment. Fig. 6 is a cross-sectional view taken along line VI-VI' in Fig. 5. Note that Fig. 6 shows a simplified configuration of the array substrate 2, and illustrates the insulating films 26, 28, the protective film 29, and the photodiode 30. A detailed configuration example of the array substrate 2 will be described later with reference to Fig. 11.

[0040] 5 and 6, the optical filter 7 is provided to cover a plurality of detection elements 3 (photodiodes 30) arranged in a matrix. The optical filter 7 is an optical element that transmits a component of the light L2 reflected by a detection object such as a finger Fg traveling in a third direction Dz toward the photodiode 30 and blocks a component traveling in an oblique direction. The optical filter 7 is also called a collimating aperture or a collimator.

[0041] The optical filter 7 has a plurality of lenses 78 provided for each of the plurality of detection elements 3. The plurality of lenses 78 are arranged in an area overlapping one detection element 3 (photodiode 30). In the example shown in FIG. 5, seven lenses 78 are provided for one detection element 3. The plurality of lenses 78 are arranged in a triangular lattice shape. More specifically, for one detection element 3, six lenses 78 are arranged in a regular hexagon shape surrounding one lens 78 located at the geometric center.

[0042] However, the number of lenses 78 arranged in one detection element 3 may be six or less, or eight or more. The arrangement of the lenses 78 is not limited to a triangular lattice pattern, and may be another arrangement such as a matrix pattern.

[0043] 6, the optical filter 7 has a first light-shielding layer 71, a second light-shielding layer 72, a filter layer 73, a barrier layer 74, a first light-transmitting resin layer 75, a second light-transmitting resin layer 76, a buffer layer 77, and a lens 78. In this embodiment, the first light-shielding layer 71, the filter layer 73, the barrier layer 74, the first light-transmitting resin layer 75, the second light-shielding layer 72, the second light-transmitting resin layer 76, the buffer layer 77, and the lens 78 are laminated in this order on the protective film 29 covering the photodiode 30.

[0044] The lens 78 is provided on and in direct contact with the buffer layer 77. The lens 78 is a convex lens. The optical axis CL of the lens 78 is provided in a direction parallel to the third direction Dz and intersects with the photodiode 30. In the example shown in FIG. 6, a plurality of lenses 78 are provided in an area overlapping one photodiode 30, and the optical axes CL of the plurality of lenses 78 each intersect with the photodiode 30.

[0045] The first light-shielding layer 71 is provided directly on and in contact with the protective film 29 of the array substrate 2. In other words, the first light-shielding layer 71 is provided between the photodiode 30 and the lens 78 in the third direction Dz. Furthermore, the first light-shielding layer 71 has a first opening OP1 in a region overlapping the photodiode 30. The first opening OP1 is formed in a region overlapping the optical axis CL of the lens 78. The first light-shielding layer 71 is formed of a metal material such as molybdenum (Mo).

[0046] The first light-shielding layer 71 can reflect components of the light L2 traveling in an oblique direction other than the light L2 that passes through the first opening OP1. In addition, since the first light-shielding layer 71 is made of a metal material, the diameter W1 (width in the first direction Dx) of the first opening OP1 can be formed with high precision. Therefore, even if the arrangement pitch or area (diameter W3) of the lenses 78 is small, the first opening OP1 can be provided in correspondence with the lenses 78.

[0047] The first light-shielding layer 71 is formed by processing a metal material deposited by sputtering or the like on the protective film 29 of the array substrate 2 to form a first opening OP1, and is different from a so-called external optical filter attached by laminating it on the protective film 29 of the array substrate 2. Laminating an external optical filter to the array substrate 2 is particularly difficult in terms of aligning the small opening in the light-shielding layer corresponding to the first opening OP1 of the first light-shielding layer 71 of this embodiment with the photodiode 30. On the other hand, since the optical filter 7 of this embodiment is formed directly on the protective film 29 of the array substrate 2, it is possible to provide the first opening OP1 on the photodiode 30 with greater accuracy than laminating an external optical filter.

[0048] Furthermore, since the first light-shielding layer 71 is made of a metal material, unlike the second light-shielding layer 72 which is made of a resin material described later, it can be formed thinner than the second light-shielding layer 72, and a first opening OP1 smaller than a second opening OP2 formed in the second light-shielding layer 72 can be formed. The thickness of the first light-shielding layer 71 is one-tenth or less of the thickness of the second light-shielding layer 72. As an example, the thickness of the first light-shielding layer 71 is 0.055 μm or more, for example, 0.065 μm, and the thickness of the second light-shielding layer is, for example, 1 μm. The first light-shielding layer 71 is formed to be extremely thin compared to the thickness of the second light-shielding layer 72.

[0049] The filter layer 73 is provided directly on and in contact with the first light-shielding layer 71, covering the first light-shielding layer 71 and the first opening OP1. The filter layer 73 is provided between the first light-shielding layer 71 and the first light-transmitting resin layer 75 in the third direction Dz. The filter layer 73 is a filter that blocks light of a predetermined wavelength band. The filter layer 73 is formed of a resin material colored in green, for example, and is an IR cut filter that blocks infrared rays. Thereby, the optical filter 7 can improve the detection sensitivity by allowing components of the light L2, for example, in a wavelength band required for fingerprint detection, to enter the photodiode 30.

[0050] The barrier layer 74 is provided to cover the filter layer 73. The first light-transmitting resin layer 75 is provided on the barrier layer 74. The barrier layer 74 is provided between the first light-shielding layer 71 and the filter layer 73, and the first light-transmitting resin layer 75 in the third direction Dz.

[0051] In this embodiment, since the barrier layer 74 is provided on the first light-shielding layer 71, even if a metal material that is easily ionized, such as molybdenum (Mo), is used as the first light-shielding layer 71, the barrier layer 74 can suppress the diffusion of reactants (e.g., Mo-based ions) generated from the first light-shielding layer 71. More specifically, when reactants (e.g., Mo-based ions) from the first light-shielding layer 71 diffuse and reach the first light-transmitting resin layer 75 and the second light-transmitting resin layer 76, they may react with the first light-transmitting resin layer 75 and the second light-transmitting resin layer 76 to form metal complexes, causing discoloration. In this embodiment, since the barrier layer 74 is provided, discoloration of the first light-transmitting resin layer 75 and the second light-transmitting resin layer 76 due to diffusion of Mo-based ions can be prevented, and a decrease in the light transmittance of the first light-transmitting resin layer 75 and the second light-transmitting resin layer 76 can be suppressed.

[0052] The barrier layer 74 is a light-transmitting resin material, and is formed of, for example, an acrylic resin material. The barrier layer 74 may be formed of any material capable of suppressing the transmission of reactants, and may be formed of, for example, the same material as the insulating film 26 or protective film 29 used in the array substrate 2, that is, a hard coat film formed of an organic material. The thickness of the barrier layer 74 is, for example, about 2.0 μm or more and 3.0 μm or less. The thickness of the barrier layer 74 is thicker than the first light-shielding layer 71 and the filter layer 73, and thinner than the first light-transmitting resin layer 75.

[0053] The first light-transmitting resin layer 75 is provided directly on and in contact with the barrier layer 74. The first light-transmitting resin layer 75 is provided between the first light-shielding layer 71 and the second light-shielding layer 72 in the third direction Dz. The first light-transmitting resin layer 75 and the second light-transmitting resin layer 76 are formed of, for example, a light-transmitting acrylic resin.

[0054] The second light-shielding layer 72 is provided directly on and in contact with the first light-transmitting resin layer 75. The second light-shielding layer 72 is provided between the first light-shielding layer 71 and the lens 78 in the third direction Dz. Furthermore, the second light-shielding layer 72 has a second opening OP2 in a region overlapping the photodiode 30 and the first opening OP1. The second opening OP2 is formed in a region overlapping with the optical axis CL of the lens 78. More preferably, the center of the second opening OP2 and the center of the first opening OP1 are provided to overlap with the optical axis CL.

[0055] The second light-shielding layer 72 is formed of, for example, a resin material colored black. As a result, the second light-shielding layer 72 functions as a light absorbing layer that absorbs components of the light L2 traveling in an oblique direction other than the light L2 that transmits through the second opening OP2. In addition, the second light-shielding layer 72 absorbs light reflected by the first light-shielding layer 71. As a result, compared to a configuration in which the second light-shielding layer 72 is formed of a metal material, it is possible to suppress the light reflected by the first light-shielding layer 71 from traveling through the first light-transmitting resin layer 75 as stray light and entering other photodiodes 30. In addition, the second light-shielding layer 72 can absorb external light that enters between the adjacent lenses 78. As a result, compared to a configuration in which the second light-shielding layer 72 is formed of a metal material, it is possible to suppress the reflected light at the second light-shielding layer 72. However, the second light-shielding layer 72 is not limited to an example in which it is formed of a resin material colored black, and may be formed of a metal material whose surface is blackened.

[0056] The second light-transmitting resin layer 76 is provided directly on and in contact with the second light-shielding layer 72. The second light-transmitting resin layer 76 is provided between the second light-shielding layer 72 and the buffer layer 77 and lens 78.

[0057] The second light-transmitting resin layer 76 is made of the same material as the first light-transmitting resin layer 75, and the refractive index of the second light-transmitting resin layer 76 is substantially equal to the refractive index of the first light-transmitting resin layer 75. This makes it possible to suppress reflection of the light L2 at the interface between the first light-transmitting resin layer 75 and the second light-transmitting resin layer 76 in the second opening OP2. However, without being limited thereto, the first light-transmitting resin layer 75 and the second light-transmitting resin layer 76 may be formed of different materials, and the refractive index of the first light-transmitting resin layer 75 and the refractive index of the second light-transmitting resin layer 76 may be different.

[0058] In this embodiment, the diameter W3 (width in the first direction Dx) of the lens 78 decreases in this order, followed by the diameter W2 (width in the first direction Dx) of the second opening OP2 and the diameter W1 (width in the first direction Dx) of the first opening OP1. The diameter W3 of the lens 78, the diameter W2 of the second opening OP2 and the diameter W1 of the first opening OP1 are each smaller than the width of the photodiode 30. The diameter W2 of the second opening OP2 and the diameter W1 of the first opening OP1 are appropriately set according to the shape (diameter W3, curvature, etc.) of the lens 78 and the distance between the lens 78 and the photodiode 30.

[0059] The thickness of the first light-transmitting resin layer 75 and the thickness of the second light-transmitting resin layer 76 are each about 10 μm or more and 30 μm or less. In the example shown in FIG. 6, the thickness of the first light-transmitting resin layer 75 is formed to be thinner than the thickness of the second light-transmitting resin layer 76. However, without being limited thereto, the thickness of the first light-transmitting resin layer 75 may be equal to the thickness of the second light-transmitting resin layer 76. Alternatively, the thickness of the first light-transmitting resin layer 75 may be formed to be thicker than the thickness of the second light-transmitting resin layer 76.

[0060] The buffer layer 77 is provided directly on and in contact with the second light-transmitting resin layer 76. The lens 78 is provided directly on and in contact with the buffer layer 77. In other words, the second light-transmitting resin layer 76 and the buffer layer 77 are laminated between the second light-shielding layer 72 and the lens 78. The film thickness of the buffer layer 77 is, for example, about 1.0 μm or more and 2.0 μm or less. The film thickness of the buffer layer 77 is thinner than the film thicknesses of the first light-transmitting resin layer 75 and the second light-transmitting resin layer 76.

[0061] The buffer layer 77 is formed of a translucent resin material, and is formed of a resin material containing a material different from that of the second translucent resin layer 76. More specifically, the buffer layer 77 is formed containing a translucent acrylic resin and a surfactant of the same type as the material used for the lens 78. The buffer layer 77 contains, for example, a fluorine-based surfactant or a Si-based surfactant. As a result, when the resin material of the lens 78 is applied and formed in the manufacturing process of the detection device 1, the wettability between the resin material of the lens 78 and the buffer layer 77 is improved compared to when the buffer layer 77 is not provided and the resin material is directly applied and formed on the second translucent resin layer 76. As a result, the shape of the lens 78 formed on the buffer layer 77 is stabilized, and the radius of curvature of the lens 78 is formed constant. That is, when one lens 78 is divided into a plurality of parts along the arc in the cross-sectional structure, the variation in the radius of curvature of each divided arc can be suppressed.

[0062] With this configuration, of the light L2 reflected by a detection object such as a finger Fg, the light L2 traveling in the third direction Dz is collected by the lens 78 as designed, passes satisfactorily through the second opening OP2 and the first opening OP1, and enters the photodiode 30. Moreover, the light L2 inclined at a predetermined angle with respect to the third direction Dz is blocked by the first light-shielding layer 71 and the second light-shielding layer 72. As a result, the detection device 1 of this embodiment can improve detection accuracy compared to a case in which the lens 78 is formed on the second light-transmitting resin layer 76 without the buffer layer 77.

[0063] As described above, the optical filter 7 is formed by directly depositing a film on the array substrate 2 and performing a process such as patterning. That is, the first light-shielding layer 71 of the optical filter 7 is provided directly on and in contact with the protective film 29, and no member such as an adhesive layer is provided between the first light-shielding layer 71 and the protective film 29. However, without being limited thereto, the optical filter 7 may be a so-called external optical filter that is bonded onto the protective film 29 of the array substrate 2 via an adhesive layer.

[0064] Moreover, the optical filter 7 is not limited to a configuration having the first light-shielding layer 71 and the second light-shielding layer 72, and may be formed of one light-shielding layer. For example, in FIG. 6, the second light-shielding layer 72 and the second light-transmitting resin layer 76 may be omitted, and a buffer layer 77 and a lens 78 may be provided on the first light-transmitting resin layer 75. Furthermore, although the filter layer 73 is provided between the first light-shielding layer 71 and the first light-transmitting resin layer 75, the position of the filter layer 73 is not limited to this. The position of the filter layer 73 can be appropriately changed according to the characteristics required for the optical filter 7 and the manufacturing process. Furthermore, the optical filter 7 is not limited to a configuration in which a light-shielding layer and a light-transmitting resin layer are laminated. For example, the optical filter 7 may have a light-guiding column type structure. That is, the optical filter 7 may have a configuration having a non-light-transmitting member formed of a black resin material and a plurality of light-transmitting regions (light-guiding columns) formed in a columnar shape penetrating the upper and lower surfaces of the non-light-transmitting member.

[0065] (Example) Fig. 7 is an explanatory diagram showing a cross-sectional structure of a lens according to an embodiment. Fig. 8 is an explanatory diagram showing a cross-sectional structure of a lens according to a comparative example. Fig. 9 is a table showing the measurement results of the lens according to the embodiment and the lens structure according to the comparative example. In Fig. 8, the lens 78 according to the embodiment is shown by a two-dot chain line for ease of understanding.

[0066] 7, a buffer layer 77 is provided on the second light-transmitting resin layer 76, and a lens 78 is formed on the buffer layer 77. In a detection device 200 and an optical filter 207 of a comparative example shown in FIG. 8, the buffer layer 77 is not provided, and a lens 278 is formed on the second light-transmitting resin layer 76.

[0067] 9, the heights H, Ha, diameters W3, W3a, radius of curvature, variation in radius of curvature, and the presence or absence of lens peeling were measured for each of the lens 78 of the example and the lens 278 of the comparative example. The radius of curvature was measured for each region of the lenses 78, 278. Specifically, the radius of curvature of the arc of the lenses 78, 278 in the range from the apex to 1 / 4 of the height H, Ha, the radius of curvature of the arc of the lenses 78, 278 in the range from the apex to 1 / 2 of the height H, Ha, and the radius of curvature of the arc of the lenses 78, 278 in the range from the apex to 1 / 1 of the height H, Ha (entire range) were obtained.

[0068] The variation in the radius of curvature shown in FIG. 9 was calculated using the following formula (1) for each of the examples and comparative examples, where the maximum radius of curvature among the radii of curvature in the three regions described above is Rmax and the minimum radius of curvature is Rmin.

[0069] ((Rmax-Rmin) / (Rmax+Rmin))×100(%) ···(1)

[0070] As shown in Figures 7 to 9, the height H of the lens 78 of the embodiment is greater than the height Ha of the lens 278 of the comparative example, and the diameter W3 of the lens 78 of the embodiment is smaller than the diameter W3a of the lens 278 of the comparative example.

[0071] The radius of curvature of lens 78 of the embodiment is formed to be a substantially constant value in each of the regions of (1 / 4)×H, (1 / 2)×H, and H. Furthermore, in lens 78 of the embodiment, the variation in the radius of curvature calculated by formula (1) is suppressed to a small value of 2.61%.

[0072] The lens 278 of the comparative example is formed with a larger radius of curvature in each of the regions of (1 / 4)×H, (1 / 2)×H, and H compared to the lens 78 of the embodiment. The radius of curvature of the lens 278 of the comparative example is formed with variation in each of the regions of (1 / 4)×H, (1 / 2)×H, and H. Specifically, the lens 278 of the comparative example has a larger radius of curvature closer to the apex (for example, in a region up to a height of (1 / 4)×H), and a smaller radius of curvature farther from the apex (for example, in a region up to a height of H). In the lens 278 of the comparative example, the variation in the radius of curvature calculated by formula (1) is 10.51%.

[0073] "Lens peeling" in Fig. 9 indicates the presence or absence of portions where the lenses 78, 278 provided in the detection area AA have peeled off from the buffer layer 77 (the second light-transmitting resin layer 76 in the comparative example) and fallen off, resulting in the lenses 78, 278 not being formed. As shown in Fig. 9, in the example, lens peeling did not occur and all of the lenses 78 were well formed. In contrast, in the comparative example, lens peeling occurred, resulting in some of the lenses 278 falling off and not being formed.

[0074] As described above, it was shown that the lens 78 according to the example has improved wettability between the lens 78 and the buffer layer 77 and improved uniformity of the curvature compared to the comparative example by providing the buffer layer 77. That is, in the cross-sectional structure of the lens 78 according to the example, the variation in the radius of curvature for each of the multiple parts divided along the arc is suppressed. Furthermore, it was shown that the lens 78 according to the example also suppresses the occurrence of lens peeling.

[0075] Next, a configuration example of the photodiode 30 and the array substrate 2 will be described. FIG. 10 is a plan view showing a photodiode of the detection device according to the embodiment. FIG. 11 is a cross-sectional view taken along line XI-XI' in FIG. 10. In FIG. 10, in order to make the drawing easier to see, a plurality of lenses 78 overlapping the photodiode 30 are shown by two-dot chain lines. FIG. 11 shows the cross-sectional configuration of the reset transistor Mrst out of the three transistors included in the detection element 3, but the cross-sectional configurations of the source follower transistor Msf and the readout transistor Mrd are similar to that of the reset transistor Mrst.

[0076] As shown in Fig. 10, the multiple scanning lines GL each extend in a first direction Dx and are arranged side by side in a second direction Dy. The multiple output signal lines SL each extend in the second direction Dy and are arranged side by side in the first direction Dx. One detection element 3 (photodiode 30) is formed in an area surrounded by two scanning lines GL and two output signal lines SL. Note that the scanning line GL shown in Fig. 10 is either the read control scanning line GLrd or the reset control scanning line GLrst (see Fig. 4).

[0077] 11, the photodiode 30 is provided on the array substrate 2, i.e., on the first main surface S1 side of the substrate 21. The substrate 21 is an insulating substrate. For example, a glass substrate such as quartz or non-alkali glass is used for the substrate 21. The substrate 21 has a first main surface S1 and a second main surface S2 opposite to the first main surface S1. Various transistors including a reset transistor Mrst, various wirings (scanning lines and signal lines), and an insulating film are provided on the first main surface S1 of the substrate 21 to form the array substrate 2.

[0078] The undercoat film 22 is provided on the first main surface S1 of the substrate 21. The undercoat film 22, the insulating films 23, 24, 25, and the insulating films 27, 28 are inorganic insulating films, such as silicon oxide (SiO2) or silicon nitride (SiN).

[0079] The semiconductor layer 61 is provided on the undercoat film 22. For example, polysilicon is used for the semiconductor layer 61. However, the semiconductor layer 61 is not limited to this, and may be a microcrystalline oxide semiconductor, an amorphous oxide semiconductor, low temperature polycrystalline silicon (LTPS), or the like.

[0080] The insulating film 23 is provided on the undercoat film 22, covering the semiconductor layer 61. The gate electrode 64 is provided on the insulating film 23. The gate electrode 68 of the source follower transistor Msf is also provided on the insulating film 23 in the same layer as the gate electrode 64. The scanning lines GL (reset control scanning line GLrst and readout control scanning line GLrd) are also provided in the same layer as the gate electrode 64. The insulating film 24 is provided on the insulating film 23, covering the gate electrode 64.

[0081] 11, the reset transistor Mrst has a top gate structure in which the gate electrode 64 is provided on the upper side of the semiconductor layer 61. However, in the detection device 1, the gate electrode 64 may have a bottom gate structure in which the gate electrode 64 is provided on the lower side of the semiconductor layer 61, or a dual gate structure in which the gate electrode 64 is provided on both the upper and lower sides of the semiconductor layer 61.

[0082] The insulating films 24 and 25 are provided on the insulating film 23, covering the gate electrode 64. The source electrode 62 and the drain electrode 63 are provided on the insulating film 25. The source electrode 62 is connected to the source region of the semiconductor layer 61 through a contact hole CH4 that penetrates the insulating films 23, 24, and 25. The drain electrode 63 is connected to the drain region of the semiconductor layer 61 through a contact hole CH3 that penetrates the insulating films 23, 24, and 25. The source electrode 62 and the drain electrode 63 are made of, for example, a TiAlTi or TiAl laminated film that is a laminated structure of titanium and aluminum.

[0083] The output signal line SL and the connection wiring SLcn are provided in the same layer as the source electrode 62 and the drain electrode 63. The connection wiring SLcn of the detection element 3 is connected to the gate electrode 68 of the source follower transistor Msf via a contact hole penetrating the insulating films 24 and 25.

[0084] Further, a first electrode 81 and a second electrode 82 are provided in a region overlapping with the photodiode 30. A capacitance Cad is formed between the first electrode 81 and the second electrode 82. The capacitance Cad is a capacitance added to the photodiode 30, and is connected in parallel with the capacitance element Cs shown in FIG. 4. The first electrode 81 and the second electrode 82 are provided by utilizing two layers among the layers constituting a transistor (for example, a reset transistor Mrst). In this embodiment, the second electrode 82 is in the same layer as the semiconductor layer 61, and is formed of the same material as the semiconductor layer 61. The first electrode 81 is in the same layer as the gate electrode 64, and is formed of the same material as the gate electrode 64.

[0085] The insulating film 26 is provided on the insulating film 25, covering a plurality of various transistors such as the reset transistor Mrst. The insulating film 26 is made of an organic material such as photosensitive acrylic. The insulating film 26 is thicker than the insulating film 25. Compared with inorganic insulating materials, the insulating film 26 has better step coverage and can flatten steps formed by various transistors and various wirings.

[0086] The photodiode 30 is provided on the insulating film 26. Specifically, the lower electrode 35 is provided on the insulating film 26 and is electrically connected to the connection wiring SLcn through the contact hole CH2. The photodiode 30 is connected to the lower electrode 35. The lower electrode 35 may have a laminated structure of titanium (Ti) and titanium nitride (TiN), for example. Since the lower electrode 35 is provided between the substrate 21 and the semiconductor layer of the photodiode 30, the lower electrode 35 functions as a light-shielding layer and can suppress the intrusion of light from the second main surface S2 side of the substrate 21 into the photodiode 30.

[0087] The photodiode 30 is configured to include a semiconductor layer having a photovoltaic effect. Specifically, the semiconductor layer of the photodiode 30 includes an i-type semiconductor layer 31, a p-type semiconductor layer 32, and an n-type semiconductor layer 33. The i-type semiconductor layer 31, the p-type semiconductor layer 32, and the n-type semiconductor layer 33 are, for example, amorphous silicon (a-Si). Note that the material of the semiconductor layers is not limited to this and may be polysilicon, microcrystalline silicon, or the like.

[0088] The p-type semiconductor layer 32 is formed by doping impurities into a-Si to form a p+ region. The n-type semiconductor layer 33 is formed by doping impurities into a-Si to form an n+ region. The i-type semiconductor layer 31 is, for example, a non-doped intrinsic semiconductor, and has lower conductivity than the p-type semiconductor layer 32 and the n-type semiconductor layer 33.

[0089] In a direction perpendicular to the surface of the substrate 21 (third direction Dz), the i-type semiconductor layer 31 is provided between the n-type semiconductor layer 33 and the p-type semiconductor layer 32. In this embodiment, the n-type semiconductor layer 33, the i-type semiconductor layer 31, and the p-type semiconductor layer 32 are stacked in this order on the lower electrode 35. In this embodiment, the upper electrode 34 is an anode electrode of the photodiode 30, and the lower electrode 35 is a cathode electrode of the photodiode 30.

[0090] The lower electrode 35 is provided extending to the outside of the photodiode 30, that is, to a region not overlapping with the n-type semiconductor layer 33, the i-type semiconductor layer 31, and the p-type semiconductor layer 32. The lower electrode 35 is electrically connected to the connection wiring SLcn, the reset transistor Mrst, and the source follower transistor Msf via a contact hole CH2 provided in the insulating film 26.

[0091] The upper electrode 34 is provided on the p-type semiconductor layer 32. The upper electrode 34 is made of a conductive material having light-transmitting properties, such as ITO (Indium Tin Oxide). The insulating film 27 is provided on the insulating film 26, covering the photodiode 30 and the upper electrode 34. A contact hole CH1 (opening) is provided in the insulating film 27 in a region overlapping with the upper electrode 34.

[0092] The connection wiring 36 is provided on the insulating film 27, and is electrically connected to the upper electrode 34 through a contact hole CH1 (opening). A reference potential VCOM (see FIG. 4) is supplied to the p-type semiconductor layer 32 through the connection wiring 36 and the upper electrode 34.

[0093] The insulating film 28 is provided on the insulating film 27, covering the upper electrode 34 and the connection wiring 36. The insulating film 28 is provided as a protective layer that suppresses the intrusion of moisture into the photodiode 30. Furthermore, a protective film 29 is provided on the insulating film 28. The protective film 29 is a hard coat film (organic protective film) made of an organic material. The protective film 29 flattens steps on the surface of the insulating film 28 formed by the photodiode 30 and the connection wiring 36.

[0094] The optical filter 7 is provided on the protective film 29. The optical filter 7 is provided directly on the protective film 29 without an adhesive layer. A cover member 122 is provided on the optical filter 7. The cover member 122 is attached to the optical filter 7 by an adhesive layer 125 (see FIG. 1). The adhesive layer 125 is, for example, a translucent optical clear adhesive (OCA).

[0095] 10 and 11 are merely examples and may be modified as appropriate. For example, the stacking order of the photodiode 30 may be reversed, and the p-type semiconductor layer 32, the i-type semiconductor layer 31, and the n-type semiconductor layer 33 may be stacked in this order on the lower electrode 35.

[0096] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such an embodiment. The contents disclosed in the embodiment are merely examples, and various modifications are possible within the scope of the present invention. Appropriate modifications made within the scope of the present invention naturally belong to the technical scope of the present invention. At least one of various omissions, substitutions, and modifications of components can be made within the scope of the gist of each of the above-mentioned embodiments and each modified example. [Explanation of symbols]

[0097] 1,200 Detection device 2 Array Board 7, 207 Optical Filter 21 Substrate 30 Photodiode 71 1st light shielding layer 72 Second light shielding layer 73 Filter Layer 74 Barrier Layer 75 First transparent resin layer 76 Second transparent resin layer 77 Buffer Layer 78, 278 Lens

Claims

1. A substrate; A photodiode provided on the substrate; a lens provided over the photodiode; a light-shielding layer provided between the photodiode and the lens, the light-shielding layer having an opening in an area overlapping the photodiode; a light-transmitting resin layer and a buffer layer laminated between the light-shielding layer and the lens, The lens is disposed directly on the buffer layer. Detection device.

2. The buffer layer is formed of a resin material containing a material different from that of the light-transmitting resin layer. The detection device according to claim 1 .

3. The buffer layer is formed of a resin material containing a surfactant of the same type as the material used for the lens. The detection device according to claim 1 .

4. The thickness of the buffer layer is smaller than the thickness of the light-transmitting resin layer. The detection device according to claim 1 .

5. A barrier layer is provided between the light-shielding layer and the light-transmitting resin layer and is made of an acrylic resin. The detection device according to claim 1 .

6. a filter layer that is provided to cover the light-shielding layer and the opening and that blocks light in a predetermined wavelength band; the barrier layer is provided over the filter layer; The light-transmitting resin layer is provided on the barrier layer.

6. The detection device according to claim 5.

7. an organic protective film covering the photodiode; The light-shielding layer is a first light-shielding layer provided on the organic protective film and having a first opening in a region overlapping the photodiode; a second light-shielding layer provided between the first light-shielding layer and the lens, the second light-shielding layer having a second opening in a region overlapping the photodiode and the first opening, The light-transmitting resin layer is a first light-transmitting resin layer provided between the first light-shielding layer and the second light-shielding layer; a second light-transmitting resin layer provided between the second light-shielding layer and the buffer layer; The detection device according to claim 1 .

8. A plurality of the lenses are provided, A plurality of the lenses are provided in an area overlapping one of the photodiodes. The detection device according to claim 1 .

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