Patent ID: 12247876

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be described in detail referring to the drawings. In this regard, the present invention is not to be limited to the embodiments described below, and can be changed as appropriate without departing from the spirit of the invention.

The accompanying drawings may schematically illustrate widths, thicknesses, shapes, or other characteristics of each part for clarity of illustration, compared to actual configurations. However, such a schematic illustration is merely an example and not intended to limit the present invention. In this specification and the drawings, some elements identical or similar to those shown previously are denoted by the same reference signs as the previously shown elements, and thus repetitive detailed descriptions of them may be omitted as appropriate.

Furthermore, in the detailed description of the present invention, when defining the positional relationship between a certain component and another component, the terms “above” and “below” include not only the case where located directly above or below the certain component, but also the case where other components are further interposed therebetween unless otherwise specified.

In the following description, the “outer side” is a side close to the outer edge of a sensing device1. In the following description, the “end portion” of each layer is a portion of each layer that is close to the outer edge of the sensing device1and includes an end surface.

[Summary of Sensing Device]

The sensing device1according to the present embodiment may detect light reflected by a finger of a user, which is a detection object pensioned on a microlens360to be described later or light transmitted through the finger of the user, thereby detecting biological information such as fingerprint information. The sensing device1also functions as a collimator, which is an optical filter for inhibiting a decrease of contrast due to crosstalk. The sensing device1may include a light source that irradiates the detection object with light so as to obtain reflected light or transmitted light used for sensing, but this will not be described in the present embodiment.

FIG.1Ais a schematic plan view of a sensing device according to the present embodiment.FIG.1Bis a block diagram showing a configuration and functions of the sensing device according to the present embodiment.

As shown inFIG.1A, the sensing device1includes a substrate110, a sensor unit10, a gate line driving circuit20, a signal line selecting circuit21, a detection circuit24, a control circuit26, and a power supply circuit28.

A control substrate600is electrically connected to the substrate110via a flexible printed board500. The flexible printed board500includes the detection circuit24. The control substrate600includes the control circuit26and the power supply circuit28. The control circuit26is a field programmable gate array (FPGA), for example. The control circuit26supplies control signals to the sensor unit10, the gate line driving circuit20, and the signal line selecting circuit21so as to control the detection operation of the sensor unit10. The power supply circuit28supplies a power supply voltage to the sensor unit10, the gate line driving circuit20, and the signal line selecting circuit21.

The sensing device1includes a detection area DA and a frame area PA. The detection area DA is an area in which the sensor unit10is provided. The frame area PA is positioned outside the detection area DA and is not provided with the sensor unit10. In other words, the frame area PA is an area between the end portion of the detection area DA and the end portion of the substrate110. The frame area PA includes a bending area BA and a terminal area TA. The bending area BA and the terminal area TA are provided at one end of the frame area PA. Wires connected to the detection area DA are disposed in the bending area BA and the terminal area TA. The substrate110and the flexible printed board500are connected in the terminal area TA.

The sensor unit10includes a plurality of pixels PX and receives light from the detection object. The pixels PX are disposed in a matrix in the detection area DA. The pixels PX include light detection sensors, which are photodiodes, and respectively output electric signals corresponding to light irradiating the respective photodiodes. Each pixel PX outputs an electric signal corresponding to the light irradiating the pixel PX to the signal line selecting circuit21as a detection signal Vdet. The sensing device1may be capable of detecting biological data, such as a blood vessel image of a finger and a palm, a pulse wave, a pulse, and a blood-oxygen saturation, based on the detection signal Vdet from each pixel PX. Each pixel PX performs detection in accordance with a gate drive signal Vgcl supplied from the gate line driving circuit20.

The gate line driving circuit20and the signal line selecting circuit21are provided in the frame area PA. Specifically, as shown inFIG.1A, the gate line driving circuit20is provided in an area of the frame area PA extending along the extension direction of the signal line SGL. The signal line selecting circuit21is provided in an area of the frame area PA extending along the extension direction of the gate line GCL, and is provided between the sensor unit10and the bending area BA.

As shown inFIG.1B, the sensing device1further includes a detection control unit30and a detection unit40. Some or all of the functions of the detection control unit30are included in the control circuit26. Further, some or all of the functions of the detection unit40other than the detection circuit24are included in the control circuit26.

The detection control unit30is a circuit that supplies control signals to the gate line driving circuit20, the signal line selecting circuit21, and the detection unit40, and controls these operations. The detection control unit30supplies control signals, such as a start signal STV, a clock signal CK, and a reset signal RST, to the gate line driving circuit20. The detection control unit30supplies control signals, such as a selection signal ASW, to the signal line selecting circuit21. The gate line driving circuit20drives the gate line GCL based on the control signals. The gate line driving circuit20sequentially or simultaneously selects a plurality of gate lines GCL, and supplies a gate drive signal Vgcl to the selected gate line GCL. In this manner, the gate line driving circuit20selects a pixel PX connected to the gate line GCL. The signal line selecting circuit21is a switching circuit that sequentially or simultaneously selects a plurality of signal lines SGL. The signal line selecting circuit21is a multiplexer, for example. The signal line selecting circuit21connects the selected signal line SGL with the detection circuit24based on the selection signal ASW supplied from the detection control unit30. This enables the signal line selecting circuit21to output a detection signal Vdet of the pixel PX to the detection unit40.

The detection unit40includes the detection circuit24, a signal processing unit44, a storage unit45, a coordinate extracting unit46, and a detection timing control unit47. The detection timing control unit47controls the detection circuit24, the signal processing unit44, and the coordinate extracting unit46to operate in synchronization based on the control signal supplied from the detection control unit30.

The detection circuit24is an analog front end circuit (AFE), for example. The detection circuit24is a signal processing circuit having at least functions of a detection signal amplifier42and an A/D converter43. The detection signal amplifier42amplifies the detection signal Vdet. The A/D converter43converts an analog signal from the detected signal amplifier42into a digital signal. The signal processing unit44is a logic circuit that detects a predetermined physical quantity entered into the sensor unit10based on the output signal of the detection circuit24. When a detection target, such as a finger and a palm, comes into contact with or is close to the detection surface, the signal processing unit44detects unevenness of the surface of the finger and the palm based on the signal from the detection circuit24. Further, the signal processing unit44detects biological data, such as a blood vessel image of a finger and a palm, a pulse wave, a pulse, and a blood-oxygen saturation, based on a signal from the detection circuit24. The storage unit45temporarily stores the signal calculated by the signal processing unit44. The storage unit45may be a random access memory (RAM) or a register circuit, for example. The coordinate extracting unit46is a logic circuit that obtains detection coordinates of unevenness of a surface of a finger and a palm, for example, when the signal processing unit44detects contact or approach of the finger or the palm. The coordinate extracting unit46is a logic circuit that obtains detection coordinates of blood vessels of a finger and a palm, for example. The coordinate extracting unit46combines detection signals Vdet from the respective pixels PX of the sensor unit10to generate two-dimensional information indicating the shape of the unevenness of the surface of the finger and the palm, for example. The coordinate extracting unit46may not calculate the detection coordinates but output the detection signal Vdet as the sensor output Vo.

[Laminate Structure of Sensing Device]

FIG.2is a schematic cross-sectional view of the sensing device1taken along the line II-II inFIG.1A.FIG.2shows a part of the detection area DA near the end portion and a part of the frame area PA. InFIG.2, hatching of some layers is omitted for clarity of the cross-sectional structure (the same applies toFIGS.3to7described later).

As shown inFIG.2, the sensing device1includes a TFT layer100including a thin film transistor TFT, an OPD layer200provided above the TFT layer100, and a sealing structure300provided above the OPD layer200.

The TFT layer100includes the substrate110and a barrier inorganic layer120provided above the substrate110. For example, the substrate110may have a two-layer structure of a glass substrate and a resin substrate provided thereon. The resin substrate may be formed of polyimide, for example. However, the present invention is not limited thereto, and the substrate110does not have a glass substrate and may be formed of only a flexible resin substrate. The barrier inorganic layer120may have a laminate structure including a plurality of layers. The TFT layer100may have an additional layer125in accordance with a position where the thin film transistor TFT is formed.

The thin film transistor TFT includes a semiconductor layer131, a gate electrode132, a source electrode133, and a drain electrode134. A gate insulating layer140is provided between the semiconductor layer131and the gate electrode132. A silicon oxide layer may be used as the gate insulating layer140. An interlayer insulating layer150is formed on the gate electrode132. The interlayer insulating layer150may have a laminate structure of a silicon nitride layer and a silicon oxide layer.

A flattening layer160is provided to cover the interlayer insulating layer150. The flattening layer160may be made of a resin having excellent surface flatness, such as photosensitive acrylic. The flattening layer160may be removed at a part that electrically connects the OPD layer200and the TFT layer100. The end portions of the flattening layer160may be positioned in the frame area PA. The flattening layer160may be partially removed in the frame area PA. An insulating layer170may be provided above the flattening layer160. Further, an inorganic insulating layer180made of an inorganic material may be provided above the insulating layer170. The inorganic insulating layer180may also be provided above the lower electrode210included in the OPD layer200so as to expose the lower electrode210. The inorganic insulating layer180may be provided above the flattening layer160in the frame area PA.

The OPD layer200includes a light detection sensor. The light detection sensor includes a lower electrode210provided above the insulating layer170, an organic layer220provided above the lower electrode210, and an upper electrode230provided above the organic layer220. The organic layer220functions as a photoelectric conversion layer. The upper electrode230is a common electrode provided across the pixels. The lower electrode210is provided corresponding to each pixel, and is electrically connected to the drain electrode134of the TFT layer100.

The sealing structure300includes a first inorganic layer310provided above the upper electrode230, a first transparent resin layer320, which is a first resin layer, provided above the first inorganic layer310, a second inorganic layer330provided above a first transparent resin layer320, and a second transparent resin layer340, which is a second resin layer provided above the second inorganic layer330. The first inorganic layer310, the first transparent resin layer320, the second inorganic layer330, and the second transparent resin layer340may have optical transparency.

The end portion of the first inorganic layer310(not shown inFIG.2) is positioned outward of an end portion220eof the organic layer220. That is, the end portion of the first inorganic layer310is positioned in the frame area PA. The first inorganic layer310is in contact with the end portion220eof the organic layer220. The first inorganic layer310is in contact with the inorganic insulating layer180on the outside of the end portion220eof the organic layer220.

The second inorganic layer330is in contact with the first inorganic layer310in the frame area PA. As described above, the layers made of the inorganic material prevent moisture from entering the organic layer220from the outside in the sealing structure300.

As shown inFIG.2, the flattening layer160and the inorganic insulating layer180formed along the flattening layer160form a wall portion165in the frame area PA. The wall portion165may be formed when the flattening layer160formed in the frame area PA is partially removed and the inorganic insulating layer180is provided above the remaining portion of the flattening layer160. The wall portion165is formed so as to prevent the resin material forming the OPD layer200and the sealing structure300from leaking out of the frame area PA when such layers are formed.FIG.2shows an example in which four wall portions165are formed side by side toward the outside, although the number of wall portions165is not limited thereto. Alternatively, the wall portion165may not be provided. That is, the flattening layer160may not be provided in the frame area PA.

As shown inFIG.2, in the present embodiment, the first inorganic layer310and the second inorganic layer330are formed along the shape of the wall portions165in the frame area PA. As described above, the inorganic layer is formed along the unevenness formed by a plurality of wall portions165, whereby the shielding property against moisture is further improved. Further, as shown inFIG.2, the end portion320eof the first transparent resin layer320may be covered with the second inorganic layer330.

In the present embodiment, the sealing structure300has the function to cover the OPD layer200so as to prevent moisture from entering the organic layer220from the outside, and also has the function as a collimator, which is an optical filter. As such, the sealing structure300includes a foundation layer350provided above the second transparent resin layer340, a microlens360provided above the foundation layer350, a first light shielding layer370provided above the first inorganic layer310, and a second light shielding layer380provided above the second inorganic layer330. The first transparent resin layer320and the second transparent resin layer340may be made of a material having high transmittance and low moisture permeability.

The foundation layer350may be made of an organic material. The organic material used as the foundation layer350improves adhesion to the microlens360. Further, processability of the microlens360is improved. The foundation layer350may be made of an inorganic material. The organic material used as the foundation layer350further improves the shielding property against moisture. The foundation layer350may also function as a layer for adjusting the focal length of the collimator.

A first opening H1is formed in the first light shielding layer370so as to allow light to enter the OPD layer200. A second opening H2is formed in the second light shielding layer380so as to allow light to enter the OPD layer200. The width of the second opening H2may be larger than the width of the first opening H1. The first opening H1and the second opening H2may be circular in a plan view. In this case, the diameter of the second opening H2may be larger than the diameter of the first opening H1in a plan view.

The first light shielding layer370and the second light shielding layer380may be made of a resin or a metal that blocks light incident thereon. For example, the first light shielding layer370formed of a thin-film metal facilitates processing and forming a small width opening. The second light shielding layer380is made of a thick black resin, which serves to block unnecessary light from the outside.

The first light shielding layer370and the second light shielding layer380allow a component of light that travels in the normal direction among the light reflected by the detection object, such as a finger, to enter the OPD layer200through the first opening H1and the second opening H2, and shield a component of light that travels in the oblique direction.

The microlens360is a convex lens. The microlens360may be circular in a plan view and have a larger diameter than the second opening H2and may be provided so as to overlap with the second opening H2in a plan view. The present invention is not limited thereto, and the microlens360may be disposed such that at least a part of the microlens360overlaps the first opening H1and the second opening H2in a plan view. A part of the light reflected by the detection object, such as a finger, is collected by the microlens360and passes through the second opening H2and the first opening H1to enter the OPD layer200.

As shown inFIG.2, the sealing structure300may include a filter layer375on the first light shielding layer370for blocking light of a specific wavelength. The filter layer375may also be provided inside the first opening H1of the first light shielding layer370. The filter layer375may be an IR (infrared rays) cut filter, for example.

As described above, the sealing structure300has the function of an optical filter in the present embodiment. In other words, the first inorganic layer310, the first transparent resin layer320, the second inorganic layer330, and the second transparent resin layer340, which function only as a layer thickness adjustment layer for ensuring the light shielding property in the optical filter, are allowed to have a function of preventing moisture from entering the organic layer220from the outside. As such, the thickness of the sensing device1can be reduced as compared with a configuration in which an optical filter is separately laminated. Further, another function is provided to the layer constituting the optical filter, and thus the layer constituting the optical filter can be effectively used.

FIG.2shows an example in which a cut line CL is formed so as to surround the detection area DA in the frame area PA. The layers above the substrate110are removed in the cut line CL. However, the configuration of the frame area PA is not limited to the example shown inFIG.2.

[First Modification]

Next, referring toFIG.3, a sensing device according to the first modification of the present embodiment will be described.FIG.3is a cross-sectional view of a sensing device according to the first modification.FIG.3shows a part corresponding to the cross-sectional view shown inFIG.2. The layers having the same functions as the layers described with reference toFIG.2are denoted by the same reference signs, and the detailed explanation thereof is omitted. In the following, the configuration different from the configuration described with reference toFIG.2will be mainly described.

InFIG.2, the second inorganic layer330extends outward from the cut line CL in the frame area PA, although as shown inFIG.3, an example of the first modification will be described in which the end portion330eof the second inorganic layer330is in contact with the first inorganic layer310inside the cut line CL. In the first modification, the foundation layer350may be made of an inorganic material.

In the first modification, the end portion330eof the second inorganic layer330is in contact with the first inorganic layer310in the frame area PA. The foundation layer350is in contact with the first inorganic layer310in the frame area PA. That is, the foundation layer350is in contact with the first inorganic layer310outside the end portion330eof the second inorganic layer330in the frame area PA. Such a configuration can prevent moisture from entering the organic layer220from the outside. As shown inFIG.3, the end portion320eof the first transparent resin layer320may be covered with the end portion330eof the second inorganic layer330.

[Second Modification]

Next, referring toFIG.4, a sensing device according to the second modification of the present embodiment will be described.FIG.4is a cross-sectional view of a sensing device according to the second modification.FIG.4shows a part corresponding to the cross-sectional view shown inFIG.2. The layers having the same functions as the layers described with reference toFIG.2are denoted by the same reference signs, and the detailed explanation thereof is omitted. In the following, the configuration different from the configuration described with reference toFIG.2will be mainly described.

In the second modification, the wall portion165is not formed in the frame area PA. The inorganic insulating layer180is provided in contact with the interlayer insulating layer150in the frame area PA.

The first inorganic layer310, the first transparent resin layer320, the second inorganic layer330, the second transparent resin layer340, and the foundation layer350are laminated so as to be gradually lowered toward the outside in the frame area PA.

The end portion310eof the first inorganic layer310, the end portion320eof the first transparent resin layer320, the end portion330eof the second inorganic layer330, the end portion340eof the second transparent resin layer340, and the end portion of the foundation layer350are positioned outward of the end portion220eof the organic layer220. The end portion310eof the first inorganic layer310, the end portion320eof the first transparent resin layer320, the end portion330eof the second inorganic layer330, the end portion340eof the second transparent resin layer340, and the end portion of the foundation layer350are positioned in the frame area PA and in contact with the inorganic insulating layer180. The foundation layer350may be made of an inorganic material in the second modification.

In the second modification described above, similarly to the embodiment and the first modification, the configuration is employed in which the sealing structure300covers the end portion220eof the organic layer220. Further, the foundation layer350made of an inorganic material is in contact with the inorganic insulating layer180. Such configurations can inhibit moisture from entering the organic layer220from the outside. The wall portion165shown inFIG.2is not provided, and thus the structure of the sealing structure300is simple in the frame area PA and can be easily molded.

[Other Modifications]

Referring toFIGS.5to7, a sensing device according to other modifications of the present embodiment will be described.FIG.5is a cross-sectional view of a sensing device according to the third modification.FIG.6is a cross-sectional view of a sensing device according to the fourth modification.FIG.7is a cross-sectional view of a sensing device according to the fifth modification.FIGS.5to7show a part corresponding to the cross-sectional views shown inFIGS.2and3. The layers having the same functions as the layers described with reference toFIGS.2and3are denoted by the same reference signs, and the detailed explanation thereof is omitted. In the following, the configuration different from the configuration described with reference toFIGS.2and3will be mainly described.

As shown inFIG.5, the sensing device according to the third modification includes the wall portion165formed therein similarly to the sensing device1shown inFIG.2. The first inorganic layer310and the second inorganic layer330are in contact with each other in the frame area PA. The sensing device according to the third modification is different from the sensing device1shown inFIG.2in that the second transparent resin layer340covers the second inorganic layer330provided along the wall portion165and extends outward of the cut line CL. The foundation layer350is provided above the second transparent resin layer340and extends outward of the cut line CL. Accordingly, the thickness of the frame area PA is substantially the same as the thickness of the detection area DA.

As shown inFIG.6, in the sensing device according to the fourth modification, the wall portion165is formed similarly to the sensing device1shown inFIG.3. In the frame area PA, the first inorganic layer310and the second inorganic layer330are in contact with each other. The sensing device according to the fourth modification is different from the sensing device1shown inFIG.3in that the foundation layer350covers the first inorganic layer310provided along the wall portion165and extends to the outer side of the cut line CL. Accordingly, the thickness of the frame area PA is substantially the same as the thickness of the detection area DA. In the fourth modification, the foundation layer350may be made of an organic material.

As shown inFIG.7, the sensing device according to the fifth modification includes the wall portion165formed therein similarly to the sensing device1shown inFIG.2. The first inorganic layer310and the second inorganic layer330are in contact with each other in the frame area PA. In the sensing device according to the fifth modification, the foundation layer350covers the second inorganic film330provided along the wall portion165and extends outward of the cut line CL. Accordingly, the thickness of the frame area PA is substantially the same as the thickness of the detection area DA In the fifth modification, the foundation layer350may be made of an organic material.

[Upper Substrate]

Referring toFIGS.8A to8C, a laminate structure above the microlens360will be described.FIGS.8A to8Care schematic diagrams showing examples of laminate structures on the microlens. As shown inFIGS.8A to8C, an upper substrate390may be provided above the microlens360. The upper substrate390may be a protective substrate for the microlens360or a scintillator for performing wavelength conversion, for example.

FIG.8Ashows an example of a spacer391that extends in the film thickness direction and forms an air layer A between the microlens360and the upper substrate390. The lower edge of the spacer391is provided above the foundation layer350, and the upper edge of the spacer391is provided above the lower surface of the upper substrate390.

FIG.8Bshows an example in which an optical clear adhesive (OCA) sheet392is used to attach the upper substrate390to the microlens360.

FIG.8Cshows an example in which the microlens360is covered with a protective layer393and the upper substrate390is attached to the protective layer393using the optical clear adhesive sheet392.

The configurations shown inFIGS.8A to8Cmay be applied to the sensing device1according to the present embodiment and the modifications described above.

[Others]

In the present embodiment and the modifications thereof, the example has been described in which the foundation layer350is provided in the sealing structure300so as to provide the microlens360, although the present invention is not limited thereto. The foundation layer350may not be provided and the microlens360may be directly provided above the second transparent resin layer340. Further, the microlens360may not be essential.

In the present embodiment and the modifications thereof, two light shielding layers are provided, although the present invention is not limited thereto and three or more layers may be provided. In this case, the number of transparent resin layers and inorganic layers may be increased in the sealing structure300according to the total number of the light shielding layers.

InFIGS.2to7, the end portions of the respective layers included in the sealing structure300are positioned in the frame area PA, although the present invention is not limited thereto. An end portion of the layer formed of an inorganic material included in the sealing structure300may be positioned at least outward of the end portion220eof the organic layer220. In other words, the end portion of the layer included in the sealing structure300may be positioned in the detection area DA.

The sealing structure300may not include the second inorganic layer330if the first inorganic layer310has sufficient sealing performance. The sealing structure300may further include a transparent resin layer and an inorganic layer above the second inorganic layer330.

Although not shown, the sensing device1may include a display panel, such as an organic EL display, above the sealing structure300.

While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention.