JP2021140268A - Capacitive fingerprint sensor and display device - Google Patents

Abstract

To provide a capacitive fingerprint sensor and a display device which can improve surface appearance.SOLUTION: A capacitive fingerprint sensor 1 comprises a fingerprint sensor unit 2 and a protective film 5. In the fingerprint sensor unit 2, detection elements 20 each of which detects changes in capacity to acquire irregularity information of a fingerprint are regularly arrayed. The protective film 5 is disposed on the fingerprint sensor unit 2, allows a finger to come into contact therewith or come close thereto, protects the fingerprint sensor unit 2 from an external environment, and is light-transmissive. The capacitive fingerprint sensor 1 further comprises a polarizer 4 and a retardation plate 3. The polarizer 4 is disposed between the fingerprint sensor unit 2 and the protective film 5 and has a polarization axis and an absorption axis to polarize visible light impinging from the outside through the protective film 5 into linearly polarized wave. The retardation plate 3 is disposed between the fingerprint sensor unit 2 and the polarizer and has a slow axis for the linearly polarized wave to circularly polarize the linearly polarized wave.SELECTED DRAWING: Figure 1

Description

The present invention relates to a capacitive fingerprint sensor and a display device including the capacitive fingerprint sensor.

The following Patent Document 1 discloses a fingerprint sensor that employs a capacitance method. The fingerprint sensor has a cover material made of clear glass, and a large number of electrodes having a predetermined pattern of the fingerprint sensor are formed on the surface of the cover material or in close proximity to the surface of the cover material. Each electrode is electrically connected to a signal processor, an electric circuit, or the like via a transparent conductor lead.

Special Table 2016-509314 Gazette

In the fingerprint sensor, electrodes, conductor leads, and a part of a signal processor or an electric circuit are formed of metal wiring. Here, when visible light is incident on the fingerprint sensor from the outside, the visible light passes through the cover material and is reflected on the surface of the metal wiring, and this reflected light projects a pattern such as an electrode on the cover material. For this reason, the appearance on the surface of the fingerprint sensor is impaired, and there is room for improvement.
Further, in the display device in which the fingerprint sensor is arranged so as to be overlapped on the display panel, the reflection of a pattern such as an electrode on the surface of the fingerprint sensor impairs the image quality of the display panel, so there is room for improvement.

The present invention provides a capacitive fingerprint sensor capable of improving the appearance on the surface and a display device including the capacitive fingerprint sensor.

The capacitive fingerprint sensor according to the first embodiment of the present invention has a fingerprint sensor unit in which detection elements for detecting a change in capacitance and acquiring unevenness information of a fingerprint are regularly arranged, and a fingerprint sensor unit. Arranged, a protective film that is in contact with or close to the finger, protects the fingerprint sensor unit against the external environment, and has translucency, and is arranged between the fingerprint sensor unit and the protective film, and is a polarizing axis. It has an absorption axis and is arranged between a polarizing plate that polarizes visible light incident from the outside through a protective film into a linearly polarized wave and a fingerprint sensor unit to the polarizing plate, and has a delay axis for the linearly polarized wave. It also has a retardation plate that circularly polarizes linearly polarized waves.

In the capacitive fingerprint sensor according to the second embodiment of the present invention, the polarizing plate is thinly formed in the capacitive fingerprint sensor according to the first embodiment.

In the capacitance type fingerprint sensor according to the third embodiment of the present invention, in the capacitance type fingerprint sensor according to the first embodiment or the second embodiment, each of the polarizing plate and the retardation plate is formed of a film. There is.

In the capacitive fingerprint sensor according to the fourth embodiment of the present invention, in the capacitive fingerprint sensor according to the first to third embodiments, at least a surface that suppresses the adhesion of fingerprints to the surface of the protective film. The treatment is applied to form a surface treatment layer.

In the capacitive fingerprint sensor according to the fifth embodiment of the present invention, in the capacitive fingerprint sensor according to the fourth embodiment, the total thickness of the polarizing plate, the retardation plate, the protective film, and the surface treatment layer is , 300 μm or less.

In the capacitance type fingerprint sensor according to the sixth embodiment of the present invention, in the capacitance type fingerprint sensor according to the fourth embodiment or the fifth embodiment, the polarizing plate, the retardation plate, the protective film and the surface treatment layer are used. The total thickness is set to 10 μm or more.

In the capacitance type fingerprint sensor according to the seventh embodiment of the present invention, in the capacitance type fingerprint sensor according to any one of the first to sixth embodiments, the fingerprint sensor portion is the surface on the protective film side. Alternatively, a part of the sensor substrate or the fingerprint sensor portion arranged on the back surface opposite to the protective film side is arranged on the surface of the protective film side, and the other part of the fingerprint sensor portion is on the protective film side. It further includes a sensor substrate disposed on the back surface on the opposite side to the above.

In the capacitance type fingerprint sensor according to the eighth embodiment of the present invention, in the capacitance type fingerprint sensor according to the seventh embodiment, a light-shielding body is arranged on the peripheral edge or the entire surface of the back surface of the sensor substrate.

In the capacitance type fingerprint sensor according to the ninth embodiment of the present invention, in the capacitance type fingerprint sensor according to the first to sixth embodiments, the fingerprint sensor portion is the surface of the retardation plate on the protective film side. Alternatively, it is arranged on the back surface opposite to the protective film side, or on both the front surface and the back surface of the retardation plate.

The display device according to the tenth embodiment of the present invention includes a display panel and a capacitive fingerprint sensor arranged on the display panel. In this display device, the capacitance type fingerprint sensor is arranged on a display panel, and has a fingerprint sensor unit in which detection elements for detecting a change in capacitance and acquiring unevenness information of the fingerprint are regularly arranged, and a fingerprint. Arranged between the fingerprint sensor and the protective film, which is arranged on the sensor and is in contact with or close to the fingerprint sensor to protect the fingerprint sensor from the external environment and has translucency. It has a polarization axis and an absorption axis, and is arranged between a polarizing plate that polarizes visible light incident from the outside through a protective film into a linearly polarized wave and a fingerprint sensor unit to the polarizing plate, and is applied to a linearly polarized wave. It has a delay axis and includes a retardation plate for circularly polarized linearly polarized waves.

The capacitive fingerprint sensor according to the eleventh embodiment of the present invention has a fingerprint sensor unit in which detection elements for detecting a change in capacitance and acquiring fingerprint unevenness information are regularly arranged, and a fingerprint sensor unit. Arranged, a protective film that is in contact with or close to the finger, protects the fingerprint sensor unit against the external environment, and has translucency, and is arranged between the fingerprint sensor unit and the protective film, and is a polarizing axis. It also has an absorption axis, and is provided with a thinly formed polarizing plate that polarizes visible light incident from the outside through a protective film into a linearly polarized wave.

The display device according to the twelfth embodiment of the present invention includes a display panel and a capacitive fingerprint sensor arranged on the display panel. In this display device, the capacitance type fingerprint sensor is arranged on the display panel, and has a fingerprint sensor unit in which detection elements for detecting a change in capacitance and acquiring unevenness information of the fingerprint are regularly arranged, and a fingerprint. Arranged on the sensor unit, the fingerprint sensor unit is protected against the external environment by contact or close contact with fingers, and is arranged between the fingerprint sensor unit and the protective film having translucency. It has a polarization axis and an absorption axis, and is provided with a thinly formed polarizing plate that polarizes visible light incident from the outside through a protective film into a linearly polarized wave.

According to the present invention, it is possible to provide a capacitive fingerprint sensor and a display device capable of improving the appearance on the surface.

It is a schematic cross-sectional view of the capacitance type fingerprint sensor which concerns on 1st Embodiment of this invention. FIG. 5 is an enlarged cross-sectional view of a main part of the fingerprint sensor portion of the capacitance type fingerprint sensor shown in FIG. 1. FIG. 5 is a schematic cross-sectional view illustrating the principle of absorbing visible light incident from the outside in the capacitive fingerprint sensor shown in FIG. 1. FIG. 5 is a schematic cross-sectional view illustrating a change in capacitance generated by finger contact (or proximity) in the capacitive fingerprint sensor shown in FIG. 1. FIG. 5 is a graph showing the relationship between the thickness of the dielectric constituting the capacitive element of the detection element of the fingerprint sensor unit and the sensor sensitivity in the capacitive fingerprint sensor shown in FIG. 1. It is a schematic cross-sectional view of the display device provided with the capacitance type fingerprint sensor which concerns on 2nd Embodiment of this invention. It is a schematic cross-sectional view of the display device which concerns on 1st modification of 2nd Embodiment. It is a schematic cross-sectional view corresponding to FIG. 7 of the display device which concerns on the 2nd modification of 2nd Embodiment. It is a schematic cross-sectional view corresponding to FIG. 7 of the display device which concerns on 3rd modification of 2nd Embodiment. It is a schematic cross-sectional view corresponding to FIG. 7 of the display device which concerns on 4th modification of 2nd Embodiment. It is a schematic cross-sectional view corresponding to FIG. 7 of the display device which concerns on 5th modification of 2nd Embodiment. It is a schematic cross-sectional view of the display device provided with the capacitance type fingerprint sensor which concerns on 3rd Embodiment of this invention.

Hereinafter, the capacitance type fingerprint sensor and the display device according to the embodiment of the present invention will be described with reference to the drawings.
Here, in the drawings, the arrow X appropriately shown indicates the X-axis direction of the three-dimensional coordinate system, and the arrow Y indicates the Y-axis direction orthogonal to the X-axis direction in the horizontal plane. Further, the arrow Z indicates the Z-axis direction orthogonal to the X-axis direction and the Y-axis direction and going from the lower side to the upper side. It should be noted that these directions are directions used for convenience to explain the embodiment, and do not limit the directions in the present invention.

[First Embodiment]
The capacitive fingerprint sensor according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
The capacitive fingerprint sensor according to this embodiment is incorporated in, for example, a smartphone. Smartphones have a mobile operating system for advanced mobile devices and are configured as mobile phones that can access the Internet.

(Basic configuration of capacitive fingerprint sensor 1)
As shown in FIG. 1, the capacitance type fingerprint sensor 1 includes a fingerprint sensor unit 2, a protective film 5, a polarizing plate 4, and a retardation plate 3 as main components. The main components are described in detail below.

(1) Configuration of Fingerprint Sensor Unit 2 The fingerprint sensor unit 2 detects, for example, a change in capacity when a finger 12 (see FIG. 4) of a regular user of a smartphone comes into contact with or approaches the surface of the protective film 5, and the fingerprint sensor unit 2 detects a fingerprint. The detection elements 20 that acquire biological information (unevenness information) are regularly arranged. In the present embodiment, since the surface treatment layer 50 described later is arranged on the surface of the protective film 5, the finger 12 is accurately in contact with or close to the surface of the surface treatment layer 50. A plurality of detection elements 20 are arranged in a matrix on the X-axis-Y-axis plane of the sensor substrate 6.

A translucent glass substrate, specifically a quartz glass substrate, is used for the sensor substrate 6. Further, as the sensor substrate 6, a film substrate having translucency can be used.

As shown in FIG. 2, one detection element 20 is configured by a series circuit of the switching element 21 and the capacitance element 22 in the present embodiment.
The switching element 21 is composed of a thin film transistor (TFT) here. That is, the switching element 21 includes a control electrode 201, an insulator 202, a channel forming region 203, a pair of main electrodes 204, and a main electrode 205.

The control electrode 201 is arranged on the surface of the sensor substrate 6, and is configured as a gate electrode in which the direction parallel to the X-axis direction is the gate width direction and the direction parallel to the Y-axis direction is the gate length direction. There is. The control electrode 201 is formed by using a metal film such as molybdenum (Mo).
The control electrodes 201 of the detection elements 20 adjacent to each other in the Y-axis direction are integrally formed, and the first signal line 200 is formed. A plurality of first signal lines 200 are extended in the Y-axis direction and arranged at regular intervals in the X-axis direction.

The insulator 202 covers the control electrode 201 and is formed on most of the surface of the sensor substrate 6. The insulator 202 is used as a gate insulating film. As the insulator 202, for example, a silicon oxide (SiO ₂ ) film, a silicon nitride (SiN _x ) film, or a composite film in which both are combined is used.

The channel formation region 203 is a region that is arranged on the control electrode 201 with an insulator 202 interposed therebetween and controls the flow of carriers by the electric field effect from the control electrode 201. For example, a silicon (Si) film or a polycrystalline silicon (poly-Si) film is used for the channel forming region 203.
The main electrode 204 is electrically connected to one end of the channel forming region 203 in the gate width direction, and is used as an n-type source electrode or an n-type drain electrode. On the other hand, the main electrode 205 is electrically connected to the other end of the channel forming region 203 in the gate width direction, and is used as an n-type drain electrode or an n-type source electrode. Each of the main electrode 204 and the main electrode 205 is formed of the same semiconductor material as the channel forming region 203, and is integrally formed with the channel forming region 203.

An insulator 206 as an interlayer insulating film is formed on the switching element 21 (on the channel forming region 203, on the main electrode 204, and on the main electrode 205). For example, a silicon nitride film is used for the insulator 206. A second signal line 207 and a connecting line 208 are arranged on the insulator 206.
The second signal line 207 is electrically connected to the main electrode 204 of the switching element 21 through a connection hole (not shown) formed in the insulator 206. The second signal line 207 is electrically connected to the main electrode 204 of the switching element 21 of each detection element 20 adjacent to each other in the X-axis direction and extends in the X-axis direction at regular intervals in the Y-axis direction. Multiple lines are arranged.
Like the second signal line 207, one end of the connection line 208 is electrically connected to the main electrode 205 of the switching element 21 through a connection hole formed in the insulator 206. The other end of the connection line 208 is electrically connected to the capacitance element 22.
A metal material such as aluminum (Al) is used for each of the second signal line 207 and the connecting line 208.

An insulator 209 as an interlayer insulating film is formed on the second signal line 207 and the connecting line 208. The same insulating material as that of the insulator 206 is used for the insulator 209. The capacitive element 22 is arranged on the insulator 209.
One end of the electrode 210 is electrically connected to the other end of the connection line 208 of the detection element 20 through a connection hole (not shown) formed in the insulator 209. The other end of the electrode 210 is arranged on the insulator 209 so as to have a certain area. For the electrode 210, a transparent electrode material such as an Indium Tin Oxide (ITO) film is used. Here, in FIG. 1, the portion indicated as the detection element 20 is schematically the electrode 210 of the capacitance element 22.
The dielectric includes an insulator 211, a retardation plate 3 laminated on the insulator 211, a polarizing plate 4, and a protective film 5 (see FIG. 1). The insulator 211 is formed on the electrode 210 and is also used as a protective film that protects the detection element 20. For the insulator 211, for example, the same insulating material as the insulator 206 is used. Each of the retardation plate 3, the polarizing plate 4, and the protective film 5 will be described in detail later. Since the surface treatment layer 50 (see FIG. 1) is formed on the surface of the protective film 5, the dielectric is configured to include the surface treatment layer 50 as well.

As shown in FIG. 2, the first signal line 200 extends to the peripheral region of the sensor substrate 6, and the extended end of the first signal line 200 is electrically connected to the wiring 213. The wiring 213 extends over the insulator 211 and is used as an external terminal. The wiring 213 is connected to the first signal line 200 through an abbreviated connection hole penetrating from the insulator 211 to the insulator 206. A transparent electrode material (transparent wiring material) such as an ITO film is used for the wiring 213.
Further, the wiring 213 is connected to the first signal line 200 via the plug wiring 212 in the connection hole. The plug wiring 212 has the same wiring layer as the second signal line 207 and the connection line 208, and is formed of the same metal material (wiring material).

On the other hand, the second signal line 207 extends to the peripheral region of the sensor substrate 6, and the extended end of the second signal line 207 is electrically connected to the wiring 214. The wiring 214 is the same wiring layer as the wiring 213, is formed of the same transparent electrode material, extends over the insulator 211, and is used as an external terminal. The wiring 214 is connected to the second signal line 207 through a connection hole (not shown) penetrating the insulator 211 and the insulator 209. Since the step shape is loose with respect to the connection structure between the first signal line 200 and the wiring 213, the plug wiring 212 is not used in the connection structure between the second signal line 207 and the wiring 214.

In the present embodiment, as shown in FIG. 2, the fingerprint sensor unit 2 is configured to have a thickness t from the control electrode 201 to the wiring 213 and the wiring 214. Here, the "thickness" is a film thickness, a layer thickness, or a plate thickness, and is a dimension in the Z-axis direction.
When a base layer of the control electrode 201 is formed between the control electrode 201 and the sensor base 6, this base layer is included in the thickness t of the fingerprint sensor unit 2.

(2) Configuration of Protective Film 5 Returning to FIG. 1, the protective film 5 is arranged on the fingerprint sensor unit 2 with the retardation plate 3 and the polarizing plate 4 interposed therebetween, and each region of the wiring 213 and the wiring 214. It is formed on substantially the entire surface of the fingerprint sensor unit 2 except for. The surface of the protective film 5 is a portion to be brought into contact with or a portion to be brought into contact with the finger 12 (see FIG. 4) of a regular user in order to perform unevenness authentication of the fingerprint. Further, the protective film 5 has a function of protecting the fingerprint sensor unit 2 against the external environment, and is configured as a part of the dielectric of the capacitive element 22 of the detection element 20 as described above.

For example, a transparent film-like glass-based material is used for the protective film 5, and it is desirable that the thickness t1 of the protective film 5 is set within the range of, for example, 3 μm to 90 μm. Preferably, the thickness t1 of the protective film 5 is set to 30 μm.

In the present embodiment, the surface of the protective film 5 is subjected to a surface treatment that effectively suppresses or prevents at least the adhesion of fingerprints. As a result of the surface treatment, the surface treatment layer 50 is formed on the surface of the protective film 5. For the surface treatment layer 50, for example, a coating layer can be practically used. This coating layer can not only suppress the adhesion of fingerprints, but also impart antifouling performance, slip performance, scratch resistance performance, antireflection performance and the like. Further, the coating layer is a film having a very thin thickness and having translucency, and does not impair the optical properties.
It is desirable that the thickness t4 of the surface treatment layer 50 is set within the range of, for example, 1 μm to 30 μm. Preferably, the thickness t4 of the surface treatment layer 50 is set to 10 μm.

(3) Configuration of Polarizing Plate 4 The polarizing plate 4 is arranged on the protective film 5 side between the fingerprint sensor unit 2 and the protective film 5. In other words, the polarizing plate 4 is formed on the entire surface of the retardation plate 3. The polarizing plate 4 is configured as a linear polarizing plate, and includes a polarization axis (or a transmission axis) and an absorption axis orthogonal to the polarization axis in the same plane. The polarizing plate 4 is incident from the outside of the capacitive fingerprint sensor 1 and polarizes the visible light that reaches the fingerprint sensor unit 2 through the protective film 5 into a linearly polarized wave.
Here, in general, "visible light" is light having a wavelength in the range of 380 nm to 760 nm. Further, the "linearly polarized wave" is a light wave that oscillates in a direction corresponding to the polarization axis direction, which is extracted from visible light that oscillates in all directions.

It is desirable that the thickness t2 of the polarizing plate 4 is set thinner than that of a general polarizing plate with a cellulose triacetate film (TAC film), for example, a polarizing plate having a thickness of 100 μm or more. .. Specifically, it is desirable that the thickness t2 of the polarizing plate 4 is set within the range of, for example, 2 μm to 60 μm. Preferably, the thickness t2 of the polarizing plate 4 is set to 20 μm. The thickness t2 of the polarizing plate 4 is set to be thinner than the thickness t1 of the protective film 5.

(4) Configuration of Phase Difference Plate 3 The retardation plate 3 is placed on the fingerprint sensor unit 2 between the fingerprint sensor unit 2 and the polarizing plate 4, and in the present embodiment between the fingerprint sensor unit 2 and the polarizing plate 4. It is arranged in a laminated manner. The retardation plate 3 is configured here as a 1/4 retardation plate (1/4 wave plate), and has a delay axis for a linearly polarized wave polarized by using the polarizing plate 4.
When the delay axis of the retardation plate 3 is set to an inclination angle of, for example, 45 degrees with respect to the absorption axis of the polarizing plate 4 when viewed from the Z-axis direction (protective film 5 side), the protective film 5 is transmitted from the outside. Then, the linearly polarized wave polarized in the polarizing plate 4 is circularly polarized into a right-handed circularly polarized wave by the retardation plate 3. On the contrary, when the delay axis is set to an inclination angle of 135 degrees (-45 degrees) with respect to the absorption axis, the linearly polarized wave polarized by the polarizing plate 4 is circularly polarized counterclockwise by the retardation plate 3. It is circularly polarized by the waves. That is, the retarding plate 3 is combined with the polarizing plate 4 to form a circular polarizing plate.

As an example, the retardation plate 3 is formed of a film obtained by stretching a polymer film uniaxially or biaxially. The thickness t3 of the retardation plate 3 is set to be relatively thin. Specifically, it is desirable that the thickness t3 of the retardation plate 3 is set within the range of, for example, 4 μm to 120 μm. Preferably, the thickness t3 of the retardation plate 3 is set to 40 μm. The thickness t3 of the retardation plate 3 is set to be slightly thicker than the thickness t1 of the protective film 5.
When the thickness t3 of the retardation plate 3 is set to 10 μm or less, it is desirable to use, for example, a so-called liquid crystal retardation plate obtained by immobilizing the orientation state of the polymerizable liquid crystal.

Here, in the capacitance type fingerprint sensor 1 according to the present embodiment, the total thickness t5 from the retardation plate 3 to the surface treatment layer 50 of the protective film 5 is set to 10 μm or more and 300 μm or less. That is, the total thickness t5 is the sum of the thickness t3 of the retardation plate 3, the thickness t2 of the polarizing plate 4, the thickness t1 of the protective film 5, and the thickness t4 of the surface treatment layer 50.

(5) Configuration of Shading Body 7 As shown in FIG. 1, the capacitance type fingerprint sensor 1 further includes a shading body 7. The light-shielding body 7 is arranged on the entire surface of the back surface of the sensor base 6 on the side opposite to the protective film 5 side and the fingerprint sensor unit 2 side, and the light-shielding body 7 effectively allows visible light to be incident from the back surface side of the sensor base 6. Can be suppressed or prevented. For the light-shielding body 7, for example, a light-shielding adhesive tape in which an acrylic adhesive is attached to an opaque polyester film is used.

(7) Configuration of Peripheral Circuit 10 As shown in FIG. 1, the capacitance type fingerprint sensor 1 configured in this way is constructed as a fingerprint sensor system including the peripheral circuit 10 and capable of acquiring unevenness information of the fingerprint. Has been done. Although the peripheral circuit 10 is shown in a simplified manner in FIG. 1, it is configured to include a drive integrated circuit (drive IC) and a detection integrated circuit (detection IC), which are integrated circuits, respectively. .. The drive integrated circuit drives the first signal line 200 shown in FIG. 2 and selects a plurality of detection elements 20 connected to the driven first signal line 200. The detection integrated circuit detects the change in capacitance detected by one or more of the detection elements 20 selected by the drive integrated circuit through the second signal line 207. In the fingerprint sensor system, it is possible to acquire the unevenness information of the fingerprint of the finger 12 (see FIG. 4) based on the change in the detected capacity.

The peripheral circuit 10 is mounted on a wiring circuit board (FPC: Flexible Printed Circuit) 9 by adopting a chip-on-film (COF: Chip On Film or Chip On Flexible) structure. The wiring circuit board 9 may be a flexible board or a non-flexible board (a board in which a PCB (Printed Circuit Board) and an FPC are combined).
The peripheral circuit 10 is electrically connected to each of the wiring 213 and the wiring 214 arranged around the surface of the fingerprint sensor unit 2 via the wiring circuit board 9. For example, anisotropic conductive particles are used for both connections.

(Action and effect)
As shown in FIG. 1, the capacitance type fingerprint sensor 1 according to the present embodiment includes a fingerprint sensor unit 2, a protective film 5, a polarizing plate 4, and a retardation plate 3. In the fingerprint sensor unit 2, detection elements 20 (see FIGS. 1 and 2) that detect changes in capacitance and acquire fingerprint unevenness information are regularly arranged. The protective film 5 is arranged on the fingerprint sensor unit 2, and the finger 12 (see FIG. 4) is in contact with or close to the protective film 5, which protects the fingerprint sensor unit 2 against the external environment and has translucency. The polarizing plate 4 is arranged between the fingerprint sensor unit 2 and the protective film 5, has a polarization axis and an absorption axis, and polarized visible light incident from the outside through the protective film 5 into a linearly polarized wave. The retardation plate 3 is arranged between the fingerprint sensor unit 2 and the polarizing plate 4, has a delay axis with respect to the linearly polarized wave, and circularly polarizes the linearly polarized wave.

As shown in FIG. 3, the visible light (external light) L1 incident on the sensor surface (surface of the surface treatment layer 50) of the capacitive fingerprint sensor 1 from the outside is the surface treatment layer 50 and the protective film 5. Each is transmitted and incident on the polarizing plate 4. In the polarizing plate 4, the visible light L1 is polarized by the linearly polarized wave L2 in the horizontal direction, and the linearly polarized wave L2 is incident on the retardation plate 3. In the retardation plate 3, the linearly polarized wave L2 is circularly polarized into, for example, a clockwise circularly polarized wave L3. The circularly polarized wave L3 is reflected by the fingerprint sensor unit 2, for example, the first signal line 200, the second signal line 207, the electrode 210 of the capacitive element 22, the wiring 213, the wiring 214, etc. (see FIG. 2), and rotates in the reverse direction. It changes to a counterclockwise circularly polarized wave (reflected light) L4. The circularly polarized wave L4 is polarized into the linearly polarized wave L5 in the vertical direction by passing through the retardation plate 3 again. This linearly polarized wave L5 does not pass through the polarizing plate 4. In other words, the linearly polarized wave L5 is absorbed by the polarizing plate 4.
Therefore, the pattern of the first signal line 200 or the like due to the reflected light of the external light is not visible (not reflected) on the surface of the protective film 5 or the surface treatment layer 50, so that the appearance of the sensor surface can be improved. Capacitive fingerprint sensor 1 can be provided.

As shown in FIG. 4, the retardation plate 3, the polarizing plate 4, the protective film 5, and the surface treatment layer 50 form a dielectric of the capacitive element 22 of the detection element 20. That is, the capacitive element 22 is constructed including one electrode 210, a dielectric, and the other electrode formed by a finger 12 in contact with or close to the surface of the surface treatment layer 50.
Therefore, the thickness of the dielectric of the capacitance element 22 is formed to be thin as a whole, and the capacitance value C of the capacitance element 22 can be increased. The capacitance value C is calculated from the following formula.
C = εS / d
Here, on the right side of the above equation, ε is the dielectric constant, S is the area of the electrode 210, and d is the thickness of the dielectric. When the capacitance value C becomes high, the sensor sensitivity of the detection element 20 can be improved in proportion to the capacitance value C. As a result, it is possible to provide the capacitance type fingerprint sensor 1 capable of improving the fingerprint authentication accuracy.

Further, in the capacitance type fingerprint sensor 1, each of the polarizing plate 4 and the retardation plate 3 shown in FIG. 1 is formed of a film. Each of the polarizing plate 4 and the retardation plate 3 formed of the film can be formed thinner than each of the polarizing plate and the retardation plate formed of, for example, a glass plate material.
Therefore, as described above, the thickness of the dielectric of the capacitance element 22 is formed to be thin as a whole, and the sensor sensitivity of the detection element 20 can be improved, so that the fingerprint authentication accuracy can be further improved. The capacitance type fingerprint sensor 1 can be provided.

Further, in the capacitance type fingerprint sensor 1, the surface of the protective film 5 shown in FIG. 1 is subjected to a surface treatment that effectively suppresses or prevents at least the adhesion of fingerprints, and the surface treatment layer 50 is formed. Since the surface treatment layer 50 makes it difficult or impossible for fingerprints to adhere, the capacitive fingerprint sensor 1 can eliminate the difficulty of seeing due to fingerprints on the sensor surface and further improve the appearance of the sensor surface. Can be provided.

Further, in the capacitance type fingerprint sensor 1, the thickness t2 of the polarizing plate 4, the thickness t3 of the retardation plate 3, the thickness t1 of the protective film 5, and the thickness t4 of the surface treatment layer 50 shown in FIG. The total thickness t5, that is, the thickness of the dielectric of the capacitive element 22 is set to 300 μm or less.
FIG. 5 shows the relationship between the thickness of the dielectric (≈d) and the sensor sensitivity (≈C) in the capacitive element 22 of the detection element 20. The horizontal axis is the thickness of the dielectric and the vertical axis is the sensor sensitivity.
As shown in FIG. 5, the sensor sensitivity increases as the thickness of the dielectric decreases. By setting the thickness of the dielectric to 300 μm or less, the minimum sensitivity reference value of the sensor sensitivity can be satisfied, and sufficient sensor sensitivity can be obtained, so that the capacitance that can improve the fingerprint authentication accuracy can be improved. A method fingerprint sensor 1 can be provided.

Further, in the capacitance type fingerprint sensor 1, the thickness t2 of the polarizing plate 4, the thickness t3 of the retardation plate 3, the thickness t1 of the protective film 5, and the thickness t4 of the surface treatment layer 50 shown in FIG. The total thickness t5, that is, the thickness of the dielectric of the capacitive element 22 is set to 10 μm or more.
As shown in FIG. 5, by setting the thickness of the dielectric to 10 μm or more, the electrostatic discharge (ESD: Electro Static Discharge) withstand voltage can be ensured.

Further, the capacitance type fingerprint sensor 1 includes a sensor base 6 as shown in FIG. The fingerprint sensor unit 2 is arranged on the surface of the sensor substrate 6 on the protective film 5 side. Since the sensor base 6 can be used as a support having mechanical strength, the peripheral circuit 10 can be easily mounted on the sensor base 6 via the wiring circuit board 9 as compared with the case where the sensor base 6 is not provided. Can be done. Therefore, the fingerprint sensor system can be easily constructed by using the capacitance type fingerprint sensor 1.

Further, as shown in FIG. 1, the capacitance type fingerprint sensor 1 is provided with a light-shielding body 7. The light-shielding body 7 is arranged on the entire surface of the back surface of the sensor substrate 6 opposite to the protective film 5 side.
Therefore, visible light (external light) incident on the back surface side of the sensor substrate 6 from the outside is shielded by the light-shielding body 7, and leakage of visible light to the front surface side of the sensor substrate 6 is effectively suppressed or prevented. Can be done. Therefore, it is possible to provide the capacitance type fingerprint sensor 1 that can further improve the appearance of the sensor surface.

[Second Embodiment]
The display device 100 provided with the capacitive fingerprint sensor 1 according to the second embodiment of the present invention will be described with reference to FIG.
In addition, in this embodiment, another embodiment described later, and a modified example, the same component as the component of the capacitance type fingerprint sensor 1 according to the first embodiment or substantially the same component Have the same reference numerals, and duplicate description will be omitted.

(Configuration of Display Device 100)
As shown in FIG. 6, the display device 100 according to the present embodiment has a capacitance type fingerprint sensor 1 similar to the capacitance type fingerprint sensor 1 shown in FIG. 1 described above, and a display panel 15. It is provided as a main component.
The display device 100 constructs a smartphone as described in the capacitive fingerprint sensor 1 according to the first embodiment. Further, the display device 100 may be constructed such as a display device of a desktop or notebook personal computer, a display device of a personal digital assistant (PDA), a display device of a portable game machine, or the like. Further, the display device 100 may construct a display device (electronic paper) formed by using the electrophoresis ink.

(1) Configuration of Capacitive Fingerprint Sensor 1 The capacitive fingerprint sensor 1 is configured to be laminated on the surface of the display panel 15. Similar to the capacitance type fingerprint sensor 1 according to the first embodiment, the capacitance type fingerprint sensor 1 according to the present embodiment has a fingerprint sensor unit 2, a retardation plate 3, and a retardation plate 3 on the surface of the sensor substrate 6. Each of the polarizing plate 4, the protective film 5, and the surface treatment layer 50 is sequentially laminated.
Further, similarly to the capacitance type fingerprint sensor 1 according to the first embodiment, in the capacitance type fingerprint sensor 1, peripheral circuits are connected to the wiring 213 and the wiring 214 of the fingerprint sensor unit 2 via the wiring circuit board 9. 10 are connected to construct a fingerprint sensor system.

(2) Configuration of Display Panel 15 Although detailed illustration and description of the configuration are omitted, the display panel 15 is composed of a transmissive type or reflective type liquid crystal display panel (LCD: Liquid Crystal Display). Further, the display panel 15 is composed of an electroluminescence (EL) display panel constructed by using an organic light emitting diode (OLED) or an inorganic light emitting diode (Inorganic LED).

The display panel 15 includes a peripheral circuit 18 and is constructed as a display system for displaying an image. When the display panel 15 is, for example, a liquid crystal display panel, the display panel 15 has pixels arranged at the intersection of the gate signal line and the video signal line. A pixel is composed of a series circuit of a pixel selection switching element and a pixel electrode. In the pixel, when a voltage is applied to the pixel electrode, the orientation of the liquid crystal enclosed between the pixel electrode and the common electrode arranged opposite to the pixel electrode is controlled.
The peripheral circuit 18 includes a selection circuit for selecting the gate signal line and a drive circuit for driving the video signal line. The peripheral circuit 18 is mounted on the wiring circuit board 17. The peripheral circuit 18 is electrically connected to each of the gate signal line and the video signal line extending to the peripheral region of the display panel 15 via the wiring circuit board 17.

(3) Configuration of Shading Body 16 In the display device 100, the capacitance type fingerprint sensor 1 is laminated on the display panel 15, and the image displayed on the display panel 15 can be seen from the sensor surface of the capacitance type fingerprint sensor 1. It is said to be a structure. Therefore, the light-shielding body 7 arranged on the back surface of the sensor substrate 6 shown in FIG. 1 is not arranged in the display device 100 according to the present embodiment.
Instead of the light-shielding body 7, a light-shielding body 16 is arranged as shown in FIG. The light-shielding body 16 is the peripheral edge of the back surface of the sensor substrate 6, and is arranged on the peripheral edge on the front surface of the display panel 15. Here, the "periphery" is used in the sense of an area outside the effective area in which the image is actually displayed on the display panel 15. In the present embodiment, the light-shielding body 16 is formed as a black matrix on the inner peripheral edge of the display panel 15. Further, the light-shielding body 16 may be formed as a decorative layer having a light-shielding property, which is laminated on the surface of the display panel 15.
Similar to the light-shielding body 7 in the capacitive fingerprint sensor 1 according to the first embodiment, the light-shielding body 16 may be formed by using a light-shielding adhesive tape and may be attached to the back surface of the sensor substrate 6. ..

(Action and effect)
As shown in FIG. 6, the display device 100 according to the present embodiment includes a display panel 15 and a capacitance type fingerprint sensor 1. The capacitance type fingerprint sensor 1 is arranged on the display panel 15, and the capacitance type fingerprint sensor 1 is substantially the same as the capacitance type fingerprint sensor 1 according to the first embodiment shown in FIG. 1 described above. It is configured to include the same components.
Therefore, with respect to the capacitance type fingerprint sensor 1, it is possible to obtain the same action and effect as the action and effect obtained by the capacitance type fingerprint sensor 1 according to the first embodiment described above.
Further, as described above, in the capacitance type fingerprint sensor 1, the pattern of the first signal line 200 or the like due to the reflected light of the visible light incident from the outside cannot be seen on the surface of the protective film 5 or the surface treatment layer 50. The appearance of the sensor surface can be improved. Therefore, in the display device 100, the image displayed on the display panel 15 through the sensor surface of the capacitive fingerprint sensor 1 looks clear without the reflection of the pattern such as the first signal line 200. The image quality of the image can be improved.

Further, in the display device 100, as shown in FIG. 6, a light-shielding body 16 is arranged on the peripheral edge of the back surface of the sensor substrate 6 and on the front surface of the display panel 15. Therefore, visible light from the peripheral edge of the sensor substrate 6 or the peripheral edge of the display panel 15 is blocked by the light-shielding body 16, and leakage of visible light to the sensor surface side can be effectively suppressed or prevented.
Therefore, the appearance of the sensor surface of the capacitive fingerprint sensor 1 can be further improved, so that the image quality of the display panel 15 can be further improved.
When the light-shielding body 16 is formed as a decorative layer, any of the peripheral edge of the surface of the sensor substrate 6, the peripheral edge of the surface of the retardation plate 3, the peripheral edge of the surface of the polarizing plate 4, and the peripheral edge of the surface of the protective film 5. It may be arranged in one or more.

(First modification)
In the display device 100 according to the first modification of the second embodiment, as shown in FIG. 7, a part of the fingerprint sensor unit 2 is arranged on the surface of the sensor base 6 on the protective film 5 side, and the sensor base 6 is provided. The other part of the fingerprint sensor unit 2 is arranged on the back surface of the protective film 6 opposite to the protective film 5 side (display panel 15 side). Similar to the fingerprint sensor unit 2 of the capacitance type fingerprint sensor 1 according to the first embodiment, the fingerprint sensor unit 2 arranges a plurality of detection elements 20 configured by a series circuit of the switching element 21 and the capacitance element 22. It is composed of.
Further, the fingerprint sensor unit 2 extends the first signal line 200 (or the second signal line 207) as a part on the front surface of the sensor base 6, and the second signal line 207 (or the second signal line 207) as another part on the back surface of the sensor base 6. Alternatively, the first signal line 200) may be extended and the detection element 20 may be configured at the intersection of the first signal line 200 and the second signal line 207.
The components other than the above of the display device 100 are the same as the components of the display device 100 according to the second embodiment.

In the display device 100 according to the first modification configured as described above, the same actions and effects as those obtained by the display device 100 according to the second embodiment can be obtained.

(Second modification)
As shown in FIG. 8, in the display device 100 according to the second modification of the second embodiment, the fingerprint sensor unit 2 is arranged on the back surface of the sensor substrate 6. The components other than the above of the display device 100 are the same as the components of the display device 100 according to the second embodiment.

In the display device 100 according to the second modification configured as described above, the same actions and effects as those obtained by the display device 100 according to the second embodiment can be obtained.

(Third modification example)
In the display device 100 according to the third modification of the second embodiment, the fingerprint sensor unit 2 is arranged on the surface of the display panel 15 as shown in FIG. That is, the sensor base 6 of the display device 100 shown in FIG. 6 described above is not arranged, and the display panel 15 has a function as a support. The components other than the above of the display device 100 are the same as the components of the display device 100 according to the second embodiment.

In the display device 100 according to the third modification configured as described above, the same actions and effects as those obtained by the display device 100 according to the second embodiment can be obtained.
Further, in the display device 100, since the fingerprint sensor unit 2 is arranged on the display panel 15 and the sensor base 6 is not provided, the thinness can be realized.

(Fourth modification)
In the display device 100 according to the fourth modification of the second embodiment, as shown in FIG. 10, a part of the fingerprint sensor unit 2 is arranged on the surface portion of the retardation plate 3 on the protective film 5 side. The other portion of the fingerprint sensor portion 2 is arranged on the back surface portion of the retardation plate 3 opposite to the protective film 5 side. Similar to the display device 100 according to the third modification, the sensor substrate 6 (see FIG. 6) is not arranged, and the display panel 15 has a function as a support. The components other than the above of the display device 100 are the same as the components of the display device 100 according to the third modification.

In the display device 100 according to the fourth modified example configured in this way, the same actions and effects as those obtained by the display device 100 according to the third modified example can be obtained. In particular, similarly to the display device 100 according to the third modification, the display device 100 according to the fourth modification does not include the sensor substrate 6, so that the thickness can be reduced.

Further, in the display device 100 according to the fourth modification, in the capacitance type fingerprint sensor 1, since the fingerprint sensor unit 2 is arranged on the retardation plate 3, the fingerprint sensor unit 2 to the surface treatment layer 50 The distance becomes shorter. That is, since the thickness t5 (see FIG. 1) of the dielectric of the capacitive element 22 of the detection element 20 can be reduced, the sensor sensitivity of the detection element 20 can be improved, and the authentication accuracy of the unevenness information of the fingerprint can be improved. It can be further improved.

(Fifth modification)
As shown in FIG. 11, in the display device 100 according to the fifth modification of the second embodiment, the fingerprint sensor unit 2 is arranged on the back surface portion of the retardation plate 3. The components other than the above of the display device 100 are the same as the components of the display device 100 according to the fourth modification.

In the display device 100 according to the fifth modified example configured in this way, the same actions and effects as those obtained by the display device 100 according to the fourth modified example can be obtained.

[Third Embodiment]
The display device 100 provided with the capacitive fingerprint sensor 1 according to the third embodiment of the present invention will be described with reference to FIG. The capacitance type fingerprint sensor 1 and the display device 100 according to the present embodiment explain an example in which the retardation plate 3 of the capacitance type fingerprint sensor 1 shown in FIG. 6 is not arranged.

(Configuration of Capacitive Fingerprint Sensor 1 and Display Device 100)
As shown in FIG. 12, the capacitance type fingerprint sensor 1 according to the present embodiment is on the surface of the display panel 15 like the display device 100 according to the second embodiment shown in FIG. 6 described above. It is arranged in a laminated manner.

The capacitance type fingerprint sensor 1 includes a fingerprint sensor unit 2, a polarizing plate 4 arranged on the fingerprint sensor unit 2, and a protective film 5 arranged on the polarizing plate 4 as main components. ing. The fingerprint sensor unit 2 is formed on the surface portion of the sensor substrate 6. Further, a surface treatment layer 50 is formed on the surface of the protective film 5.
Here, the polarizing plate 4 has a thickness thinner than the thickness t1 of the protective film 5, similar to the polarizing plate 4 of the capacitive fingerprint sensor 1 according to the first embodiment shown in FIG. It is set to t2.

In the capacitive fingerprint sensor 1 of the display device 100 configured as described above, the retardation plate 3 (see FIGS. 1 and 6) is not arranged between the fingerprint sensor unit 2 and the polarizing plate 4. That is, only the single-layer polarizing plate 4 is arranged between the fingerprint sensor unit 2 and the protective film 5.
The components other than the above of the capacitance type fingerprint sensor 1 and the display device 100 are the same as the components of the capacitance type fingerprint sensor 1 and the display device 100 according to the second embodiment.

(Action and effect)
As shown in FIG. 12, the capacitance type fingerprint sensor 1 according to the present embodiment includes a fingerprint sensor unit 2, a protective film 5, and a polarizing plate 4.
In the fingerprint sensor unit 2, detection elements 20 that detect changes in capacitance and acquire fingerprint unevenness information are regularly arranged (see FIG. 2). The protective film 5 is arranged on the fingerprint sensor unit 2, and the finger 12 (see FIG. 4) is in contact with or close to the protective film 5, which protects the fingerprint sensor unit 2 against the external environment and has translucency. The polarizing plate 4 is arranged between the fingerprint sensor unit 2 and the protective film 5, has a polarizing axis and an absorption axis, and changes visible light incident from the outside through the protective film 5 into a linearly polarized wave. The polarizing plate 4 is formed thinner than the protective film 5.
Here, when the visible light L1 (see FIG. 3) incident from the outside passes through each of the surface treatment layer 50 and the protective film 5, further passes through the polarizing plate 4, and is deflected by the linearly polarized wave L2. A part of the visible light L1 is absorbed (cut) by the polarizing plate 4. A part of the reflected light reflected by the linearly polarized wave L2 on the first signal line 200 or the like of the fingerprint sensor unit 2 is similarly absorbed by the polarizing plate 4.
Therefore, the pattern of the first signal line 200 or the like due to the reflected light of the external light is difficult to see (difficult to be reflected) on the surface of the protective film 5 or the surface treatment layer 50, so that the appearance of the sensor surface can be improved. Capacitive fingerprint sensor 1 can be provided.

Further, in the capacitance type fingerprint sensor 1, as shown in FIG. 12, the thickness t2 of the polarizing plate 4 is formed thinner than the thickness t1 of the protective film 5. That is, the total thickness t6 of the polarizing plate 4, the protective film 5, and the surface treatment layer 50 is formed thin, and the thickness of the dielectric of the capacitive element 22 of the detection element 20 (see FIG. 4) is the retardation plate 3. Is not arranged, so it is formed quite thinly. Therefore, since the sensor sensitivity of the detection element 20 can be improved, it is possible to provide the capacitance type fingerprint sensor 1 which can further improve the fingerprint authentication accuracy.

Further, as shown in FIG. 12, the display device 100 according to the present embodiment includes a display panel 15 and a capacitance type fingerprint sensor 1 arranged on the display panel 15.
As described above, in the capacitance type fingerprint sensor 1, the pattern of the first signal line 200 or the like due to the reflected light of the visible light incident from the outside becomes difficult to see on the surface of the protective film 5 or the surface treatment layer 50, so that the sensor The appearance of the surface can be improved. Therefore, in the display device 100, the image displayed on the display panel 15 is less likely to be reflected through the sensor surface of the capacitive fingerprint sensor 1, so that the image quality of the display device 100 can be improved.

[Other embodiments]
The present invention is not limited to the above-described embodiments and modifications, and various modifications can be made without departing from the gist thereof.
For example, in the above embodiment, an example in which the present invention is applied to a capacitive fingerprint sensor or a display device used in a smartphone, a personal computer, a mobile information terminal, or the like has been described, but the present invention is a device other than the above. It is applicable to the capacitive fingerprint sensor or display device of. Specifically, the present invention is used to authenticate the unevenness of a user's fingerprint in an automated teller machine (ATM) installed in a bank or a store, a ticket issuing machine installed in a station, or the like. It can be applied to a capacitive fingerprint sensor or a display device.
Furthermore, the present invention is also applicable to a capacitive fingerprint sensor assembled in a vehicle such as an automobile.
Further, focusing on the improvement of the appearance of the fingerprint sensor on the sensor surface, the present invention relates to a fingerprint sensor that employs another method such as a resistance film type fingerprint sensor and an ultrasonic type fingerprint sensor, and a display device provided with this fingerprint sensor. Applicable.

As described above, the present invention is widely applicable to a capacitive fingerprint sensor, a display device, and a device constructed including the capacitive fingerprint sensor or the display device.

1 Capacitive fingerprint sensor 10, 18 Peripheral circuit 100 Display device 12 Finger 15 Display panel 2 Fingerprint sensor part 20 Detection element 21 Switching element 22 Capacitive element 3 Phase difference plate 4 Plate plate 5 Protective film 50 Surface treatment layer 6 Sensor substrate 7, 16 Shading body 9, 17 Wiring circuit board

Claims (12)

A fingerprint sensor unit in which detection elements that detect changes in capacitance and acquire fingerprint unevenness information are regularly arranged,
A protective film disposed on the fingerprint sensor unit, which is in contact with or close to the finger, protects the fingerprint sensor unit against the external environment, and has translucency.
A polarizing plate disposed between the fingerprint sensor unit and the protective film, having a polarization axis and an absorption axis, and polarizing visible light incident from the outside through the protective film into a linearly polarized wave.
A retardation plate which is arranged between the fingerprint sensor unit and the polarizing plate, has a delay axis for the linearly polarized wave, and circularly polarizes the linearly polarized wave.
Capacitive fingerprint sensor equipped with. The capacitive fingerprint sensor according to claim 1, wherein the polarizing plate is thinly formed. The capacitive fingerprint sensor according to claim 1 or 2, wherein each of the polarizing plate and the retardation plate is made of a film. The capacitance type fingerprint sensor according to any one of claims 1 to 3, wherein the surface of the protective film is subjected to at least a surface treatment for suppressing the adhesion of fingerprints to form a surface treatment layer. The capacitive fingerprint sensor according to claim 4, wherein the total thickness of the polarizing plate, the retardation plate, the protective film, and the surface treatment layer is set to 300 μm or less. The capacitive fingerprint sensor according to claim 4 or 5, wherein the total thickness of the polarizing plate, the retardation plate, the protective film, and the surface treatment layer is set to 10 μm or more. A sensor substrate in which the fingerprint sensor unit is arranged on the front surface on the protective film side or the back surface on the side opposite to the protective film side, or a part of the fingerprint sensor unit is arranged on the surface on the protective film side. The static device according to any one of claims 1 to 6, wherein the other part of the fingerprint sensor unit further includes a sensor substrate disposed on the back surface opposite to the protective film side. Electric capacity type fingerprint sensor. The capacitive fingerprint sensor according to claim 7, wherein a light-shielding body is arranged on the peripheral edge or the entire surface of the back surface of the sensor substrate. Claim 1 in which the fingerprint sensor unit is arranged on the front surface of the retardation plate on the protective film side or the back surface opposite to the protective film side, or on both the front surface and the back surface of the retardation plate. The capacitive fingerprint sensor according to any one of claims 6. Display panel and
A capacitance type fingerprint sensor arranged on the display panel is provided.
The capacitive fingerprint sensor is
A fingerprint sensor unit, which is arranged on the display panel and in which detection elements for detecting a change in capacitance and acquiring fingerprint unevenness information are regularly arranged,
A protective film disposed on the fingerprint sensor unit, which is in contact with or close to the finger, protects the fingerprint sensor unit against the external environment, and has translucency.
A polarizing plate disposed between the fingerprint sensor unit and the protective film, having a polarization axis and an absorption axis, and polarizing visible light incident from the outside through the protective film into a linearly polarized wave.
A display device provided between the fingerprint sensor unit and the polarizing plate, having a delay axis for the linearly polarized wave, and a retardation plate for circularly polarized the linearly polarized wave. A fingerprint sensor unit in which detection elements that detect changes in capacitance and acquire fingerprint unevenness information are regularly arranged,
A protective film disposed on the fingerprint sensor unit, which is in contact with or close to the finger, protects the fingerprint sensor unit against the external environment, and has translucency.
It is disposed between the fingerprint sensor unit and the protective film, has a polarization axis and an absorption axis, and polarized visible light incident from the outside through the protective film into a linearly polarized wave, and is further formed thinner. Board and
Capacitive fingerprint sensor equipped with. Display panel and
A capacitance type fingerprint sensor arranged on the display panel is provided.
The capacitive fingerprint sensor is
A fingerprint sensor unit, which is arranged on the display panel and in which detection elements for detecting a change in capacitance and acquiring fingerprint unevenness information are regularly arranged,
A protective film disposed on the fingerprint sensor unit, which is in contact with or close to the finger, protects the fingerprint sensor unit against the external environment, and has translucency.
A thinly formed polarizing plate that is disposed between the fingerprint sensor unit and the protective film, has a polarization axis and an absorption axis, and polarizes visible light incident from the outside through the protective film into a linearly polarized wave. And, the display device equipped with.

Images