CN112749579A

CN112749579A - Ultrasonic fingerprint module, manufacturing method thereof and electronic equipment

Info

Publication number: CN112749579A
Application number: CN201911039475.0A
Authority: CN
Inventors: 刘宣宣; 朱晃亿
Original assignee: Nanchang OFilm Biometric Identification Technology Co Ltd
Current assignee: Nanchang OFilm Biometric Identification Technology Co Ltd
Priority date: 2019-10-29
Filing date: 2019-10-29
Publication date: 2021-05-04

Abstract

The invention discloses an ultrasonic fingerprint module, a manufacturing method and electronic equipment thereof. The ultrasonic fingerprint module comprises an ultrasonic detection layer and a reflection layer, the ultrasonic detection layer has an ultrasonic receiving surface, and the reflection layer is arranged on the The side of the ultrasonic detection layer away from the ultrasonic receiving surface, the reflective layer is used to reflect the ultrasonic waves emitted from the ultrasonic detection layer, the reflective layer contains a leveling agent, and the leveling agent is used to improve the The surface leveling property during the manufacturing process of the reflective layer is improved, and the surface leveling property of the finally formed reflective layer is improved. The reflective layer can reflect the ultrasonic waves emitted from the ultrasonic detection layer toward the fingerprint to be detected, so that the ultrasonic signal received by the fingerprint to be detected is strengthened, the intensity of the ultrasonic signal emitted by the ultrasonic fingerprint module toward the fingerprint to be detected is improved, and the fingerprint recognition is improved. efficiency.

Description

Ultrasonic fingerprint module, manufacturing method thereof and electronic equipment

Technical Field

The invention relates to the technical field of fingerprint identification, in particular to an ultrasonic fingerprint module, a manufacturing method thereof and electronic equipment.

Background

At present, the ultrasonic fingerprint module is compared through the ultrasonic signal that reflects back from user fingerprint valley region and the ultrasonic signal that reflects back from user fingerprint ridge region to discern user's fingerprint. However, under the condition that ultrasonic wave fingerprint module sees through ultrasonic signal easily, the ultrasonic signal intensity that leads to ultrasonic wave fingerprint module to acquire reduces, and the ultrasonic signal of the valley region that is difficult to distinguish and the ultrasonic signal difference of ridge region have reduced fingerprint identification efficiency.

Disclosure of Invention

An object of the application is to provide an ultrasonic fingerprint module for improving fingerprint identification efficiency, a manufacturing method thereof and electronic equipment.

The application provides an ultrasonic wave fingerprint module, wherein, ultrasonic wave fingerprint module includes ultrasonic detection layer and reflection stratum, the ultrasonic detection layer has the ultrasonic wave receiving face, the reflection stratum set up in the ultrasonic detection layer is kept away from the one side of ultrasonic wave receiving face, the reflection stratum is used for right following the ultrasonic wave that the ultrasonic detection layer jetted out reflects, the reflection stratum contains the flatting agent, the flatting agent is used for improving surface leveling nature of reflection stratum preparation in-process to and improve the surface leveling nature of the reflection stratum of final formation, through the flatting agent improves the surface leveling nature of reflection stratum makes the roughness on surface of reflection stratum effectively reduces, has guaranteed the reflection stratum is to ultrasonic signal's even reflection, makes the fingerprint identification efficiency of ultrasonic wave fingerprint module improves.

The mass ratio of the leveling agent in the reflecting layer is 0.2-1.5%, so that the surface leveling property of the reflecting layer is effectively reduced.

Wherein the flatting agent comprises a fluorocarbon flatting agent so as to ensure the substrate wettability and the anti-cratering capacity of the reflecting layer.

The fluorocarbon leveling agent is fluorocarbon organic modified siloxane, and the surface stability of the reflecting layer is further ensured.

The leveling agent also comprises a polyether siloxane copolymer, so that the polyether siloxane copolymer can be well complemented with the fluorocarbon leveling agent, the reflecting layer is ensured to have good leveling property and smooth surface, and the roughness of the reflecting layer can be less than 0.5 Rz/um.

The mass ratio of the fluorocarbon organic modified siloxane in the reflecting layer is 0.1-0.75%, and the mass ratio of the polyether siloxane copolymer in the reflecting layer is 0.1-0.75%, so that the surface roughness of the reflecting layer is effectively reduced, and the SNR value and the OD value of the ultrasonic fingerprint module are effectively increased.

The mass ratio of the fluorocarbon organic modified siloxane in the reflecting layer is 0.2-0.6% so as to further reduce the surface roughness of the reflecting layer.

The mass ratio of the fluorocarbon organic modified siloxane in the reflecting layer is 0.5%, the surface roughness of the reflecting layer is further reduced, and the SNR value and the OD value of the ultrasonic fingerprint module are further increased.

Wherein the mass ratio of the polyether siloxane copolymer in the reflecting layer is 0.2-0.6% so as to further reduce the surface roughness of the reflecting layer.

Wherein, the polyether siloxane copolymer is 0.5%, the surface roughness of the reflecting layer is further reduced, and the SNR value and the OD value of the ultrasonic fingerprint module are further increased.

The reflecting layer contains carbon powder and a resin material, and the carbon powder is mixed into gaps among molecules in the resin material to reduce the surface roughness of the reflecting layer, so that the surface roughness of the reflecting layer is effectively reduced.

Wherein, ultrasonic detection layer is including the substrate layer, pixel electrode layer, piezoelectric layer and the conducting electrode that stack gradually the setting, the reflection stratum set up in the conducting electrode is kept away from the one side of piezoelectric layer makes ultrasonic fingerprint module is thin, and is convenient ultrasonic fingerprint module is applied to in electronic equipment's the display screen.

The ultrasonic detection layer comprises two or more layers of conductive electrodes, so that the ultrasonic detection layer is convenient to form, and the signal conduction performance of the ultrasonic detection layer is improved.

Wherein, the thickness of reflection stratum is 5 microns to 30 microns for the surface roughness of reflection stratum effectively reduces, just the fingerprint image definition that the ultrasonic wave fingerprint module was acquireed effectively improves.

Wherein, the thickness of reflection stratum is 20 microns to 30 microns for the surface roughness of reflection stratum further reduces, the fingerprint image definition that the ultrasonic wave fingerprint module was obtained further improves.

Wherein the thickness of the reflective layer is 25 micrometers, so that the surface roughness of the reflective layer is further reduced, and the SNR value and the LPMM value of the ultrasonic fingerprint module are more excellent.

The application also provides a manufacturing method of the ultrasonic fingerprint module, wherein the manufacturing method of the ultrasonic fingerprint module comprises the following steps:

providing an ultrasonic detection layer having an ultrasonic receiving face and a detection layer bottom face disposed opposite the ultrasonic receiving face;

providing a liquid molding material containing a leveling agent;

will liquid forming material lay in on the detection layer bottom surface, treat form the reflection stratum after liquid forming material solidifies, the reflection stratum covers the ultrasonic wave receiving surface on ultrasonic detection layer, through the flatting agent improves the surface smoothness nature of reflection stratum makes the roughness on surface of reflection stratum effectively reduces, has guaranteed the reflection stratum is to ultrasonic signal's even reflection, makes the fingerprint identification efficiency of ultrasonic fingerprint module improves.

The liquid ink material also comprises carbon powder particles, a resin material and a defoaming agent, and the resin material, the carbon powder particles, the flatting agent and the defoaming agent are mixed and stirred to form the liquid ink material, so that the surface roughness of the reflecting layer is effectively reduced, and bubbles in the reflecting layer are reduced, and the reflection efficiency of the reflecting layer on ultrasonic signals is improved.

The application also provides an electronic equipment, wherein, electronic equipment includes foretell ultrasonic fingerprint module, makes electronic equipment can satisfy diversified fingerprint identification requirement, improves fingerprint identification efficiency.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic view of an ultrasonic fingerprint module according to an embodiment of the present disclosure;

fig. 2 is another schematic view of an ultrasonic fingerprint module according to an embodiment of the present disclosure;

fig. 3 is another schematic diagram of an ultrasonic fingerprint module according to an embodiment of the present disclosure;

fig. 4 is a schematic flowchart illustrating a manufacturing method of an ultrasonic fingerprint module according to an embodiment of the present disclosure;

FIG. 5 is a schematic view of a display screen assembly provided by an embodiment of the present application;

FIG. 6 is another schematic view of a display screen assembly provided by an embodiment of the present application;

FIG. 7 is a schematic view of a display screen assembly provided in accordance with another embodiment of the present application;

FIG. 8 is another schematic view of a display screen assembly provided in accordance with another embodiment of the present application;

FIG. 9 is a schematic view of a display screen assembly provided in accordance with another embodiment of the present application;

FIG. 10 is a schematic view of a display screen assembly provided in accordance with another embodiment of the present application;

fig. 11 is a schematic cross-sectional view of an electronic device provided in an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

Referring to fig. 1, the present invention provides an ultrasonic fingerprint module 100, where the ultrasonic fingerprint module 100 includes an ultrasonic detection layer 10 and a reflection layer 20, the ultrasonic detection layer 10 has an ultrasonic receiving surface 11, the reflection layer 20 is formed on a surface of the ultrasonic detection layer 10 away from the ultrasonic receiving surface 11, and the reflection layer 20 can block ultrasonic waves from exiting from the surface away from the ultrasonic detection layer 10 and can reflect an ultrasonic signal transmitted from the ultrasonic detection layer 10 to the ultrasonic detection layer 10.

It can be understood that the ultrasonic fingerprint module 100 can detect the fingerprint of the user by using the ultrasonic signal, thereby identifying the fingerprint image of the user. The ultrasonic fingerprint module 100 may be applied to an electronic device, which may be a mobile phone, a tablet computer, a notebook computer, a media player, or a financial terminal device such as an Automated Teller Machine (ATM).

Through set up reflection stratum 20 on ultrasonic detection layer 10 at ultrasonic fingerprint module 100, utilize reflection stratum 20 can keep out and reflect ultrasonic signal for ultrasonic signal that ultrasonic detection layer 10 can be received strengthens, has improved ultrasonic detection layer 10 and has improved fingerprint identification efficiency to ultrasonic signal receiving efficiency.

In this embodiment, the ultrasonic detection layer 10 can transmit an ultrasonic signal and can sense the ultrasonic signal to recognize the fingerprint of the user. The ultrasonic detection layer 10 may emit a first ultrasonic signal 01 toward a side away from the reflective layer 20 and a second ultrasonic signal 02 toward the reflective layer 20. Ultrasonic fingerprint module 100 is applied to in the electronic equipment, and the user finger is close to in ultrasonic fingerprint module 100 deviates from reflection stratum 20 one side, first ultrasonic signal 01 is towards user's fingerprint transmission, second ultrasonic signal 02 warp reflection stratum 20 keeps out and is faced ultrasonic detection layer 10 reflects back and forms third ultrasonic signal 03. The third ultrasonic signal 03 is also emitted towards the user fingerprint. The third ultrasonic signal 03 and the first ultrasonic signal 01 can be emitted toward the fingerprint of the user after forming resonance.

It can be understood that the fingerprint of the user receives the ultrasonic signal after resonance and then reflects the ultrasonic signal back to the ultrasonic detection layer 10, so that the fingerprint detection signal sensed by the ultrasonic detection layer 10 is enhanced. The ultrasonic detection layer 10 receives an ultrasonic detection signal through the ultrasonic receiving surface 11, and acquires a user fingerprint image. Because the user fingerprint has a wave area and a valley area, the wave area and the valley area have different reflectivity to the ultrasonic initial signal, and the ultrasonic detection signal reflected by the user fingerprint has a wave signal capable of reflecting the wave area and a valley signal capable of reflecting the valley area. And comparing the wave signal with the valley signal, and processing the wave signal and the valley signal after acquiring the difference data of the wave signal and the valley signal so as to acquire the fingerprint image of the user.

In this embodiment, the ultrasonic detection layer 10 forms a fingerprint recognition area in an area covered by the ultrasonic fingerprint module 100. Ultrasonic fingerprint module 100 adopts large-area ultrasonic detection layer 10, makes the length dimension of the fingerprint identification area of ultrasonic fingerprint module 100 can be 30mm, width dimension can be 20 mm. Ultrasonic wave fingerprint module 100 has the bigger fingerprint identification area than the present fingerprint module that has less fingerprint identification area, can be applicable to the fingerprint unblock scene of large tracts of land to and can realize the blind unblock of fingerprint, and conveniently utilize fingerprint unblock control electronic equipment program to start etc.. For example, ultrasonic fingerprint module 100 is applicable to more in the comprehensive screen cell-phone, satisfies large tracts of land fingerprint identification demand. Of course, in other embodiments, the length of the fingerprint identification area of the ultrasonic fingerprint module 100 may also be 40mm or more than 40mm, and the width dimension may be 30mm or more than 30 mm.

In this embodiment, because the regional increase of fingerprint identification module 100 leads to the area increase of fingerprint detection layer 10, but reflecting layer 20 can adopt printing technology, or vacuum evaporation technology, or spraying technology etc. large tracts of land processing technology shaping in on the fingerprint detection layer 10 to avoid reflecting layer 20 and fingerprint detection layer 10's interface to produce the bubble, avoid leading to ultrasonic reflection efficiency inhomogeneous because of the bubble, thereby guaranteed fingerprint identification's validity. The reflective layer 20 may be an insulating ink. The surface of the reflecting layer 20, which is far away from the ultrasonic detection layer, is in contact with air, an ultrasonic reflecting surface is formed on an interface between the reflecting layer 20 and the air, and the interface between the reflecting layer 20 and the air has higher ultrasonic reflectivity by utilizing the difference between the acoustic impedance of the reflecting layer 20 and the acoustic impedance of the air, wherein the larger the difference is. The acoustic impedance of the reflective layer 20 is proportional to the elastic modulus, so that the larger the elastic modulus of the reflective layer 20 is, the larger the acoustic impedance of the reflective layer 20 is. In this embodiment, the elastic modulus of the reflective layer 20 is substantially equal to that of the plastic film, so that the reflective layer 20 has a good shielding effect on the ultrasonic signal, and the interface of the reflective layer 20 contacting with air has a good reflection efficiency on the ultrasonic wave. The reflecting layer 20 resists and reflects the ultrasonic signal sent by the ultrasonic detection layer 10, so that the ultrasonic wave received by the user fingerprint is strengthened, the ultrasonic detection layer 10 receives the ultrasonic wave reflected by the user fingerprint, and the identification efficiency of the ultrasonic detection layer 10 is improved. The reflecting layer 20 also has a protective effect with the ultrasonic detection layer 10, so as to ensure the safety of the ultrasonic detection layer 10. The reflecting layer 20 also has the performance of resisting ultrasonic waves transmitted from outside air, so that ultrasonic signals of an external environment are resisted, the ultrasonic detection layer 10 is prevented from being interfered by environmental ultrasonic waves to identify the ultrasonic signals reflected from the user fingerprint, and the accuracy of identifying the user fingerprint by the ultrasonic detection layer 10 is ensured.

It is understood that the reflective layer 20 is provided with a resin material, for example, the reflective layer 20 is provided with any one or more of acrylic resin, polyester resin, isocyanate resin, phenoxy resin, and epoxy resin. As a preferred embodiment, the reflective layer 20 is provided with an epoxy material. The reflective layer 20 is made of resin material with insulation property to ensure that the reflective layer 20 can perform insulation protection function on the ultrasonic detection layer, and the cured resin material has an elastic modulus similar to that of a plastic sheet to ensure that the reflective layer 20 has substantially the same ultrasonic reflection efficiency as the plastic sheet.

In the process of using the material of the reflecting layer 20, the reflecting layer 20 made of various different materials can be formed on the multiple groups of fingerprint detection layers 10 through a screen printing process so as to obtain samples of the multiple groups of ultrasonic fingerprint detection modules 100. SNR (SIGNAL to NOISE RATIO) value detection is carried out on samples of the multiple groups of ultrasonic fingerprint detection modules 100 to obtain the average SNR value of the samples of the multiple groups of ultrasonic fingerprint detection modules 100, and then the reflecting layer 20 material with the optimal SNR average value is selected after the multiple groups of SNR average values are compared. The SNR value can be tested by an ultrasonic fingerprint testing instrument.

Specifically, a first set of samples of the ultrasonic fingerprint module 100 is provided, and the reflective layer 20 of the set of samples is made of acrylic resin. A second set of samples of the ultrasonic fingerprint module 100 is provided, and the reflective layer 20 of the set of samples is made of polyester resin. A third set of samples of the ultrasonic fingerprint module 100 is provided, and the reflective layer 20 of the set of samples adopts a mixed resin of acrylic resin, isocyanate resin and polyester resin. A fourth set of samples of the ultrasonic fingerprint module 100 is provided, and the reflective layer 20 of the set of samples is made of phenoxy resin. A fifth set of samples of the ultrasonic fingerprint module 100 is provided, and the reflective layer 20 of the set of samples is made of epoxy resin 1, and the epoxy resin 1 may be conventional epoxy resin. Providing a sixth group of samples of the ultrasonic fingerprint module 100, wherein the reflecting layer 20 of the group of samples adopts epoxy resin 2, the specification of the epoxy resin 2 is different from that of the epoxy resin 1, and the CAS number of the epoxy resin 2 is 38891-59-7. The average SNR values of the first, second, third, fourth, fifth and sixth sets of samples were 8.10, 3.77, 7.38, 8.54, 8.89 and 10.33, respectively. The SNR values of the samples in the first group are 8.10, 8.75, 8.85, 7.48, 7.45, 7.89, 8.16, respectively. The SNR values of the samples in the second group are 3.77, 3.89, 3.87, 3.22, 3.93, 4.08 and 3.61 respectively. The SNR values of the samples in the third group are 7.38, 8.18, 7.09, 7.75, 7.39, 6.84 and 7.02 respectively. The SNR values of the samples in the fourth group were 8.54, 8.65, 9.01, 8.76, 7.68, 8.68, 8.46, respectively. The SNR values of the samples in the fifth group are 8.89, 8.33, 8.07, 9.69, 8.94 and 9.40 respectively. The SNR values of the samples in the sixth group were 10.33, 9.63, 10.47, 10.99, 10.56, 10.03, 10.32, respectively. Further, the SNR average values of the first, second, third, fourth, fifth, and sixth groups of samples were 8.10, 3.77, 7.38, 8.54, 8.89, and 10.33, respectively. It can be seen that the reflecting layer 20 of the sixth group of ultrasonic fingerprint module 100 samples adopts epoxy resin 2, and the average SNR value is the best, so that the epoxy resin 2 is used as the material of the reflecting layer 20, and the fingerprint identification efficiency of the ultrasonic fingerprint module 100 is better. Among them, epoxy resin 1 is different from epoxy resin 2 in specification. Specifically, the CAS number of the epoxy resin 2 is 38891-59-7.

The ultrasonic detection layer 10 has a detection layer bottom surface 12 opposite to the ultrasonic receiving surface 11, and the reflection layer 20 is formed on the detection layer bottom surface 12 through a printing process. The reflective layer 20 may be formed on the bottom surface 12 of the detection layer by a TFT (Thin Film Transistor) printing process. Utilize the reflection stratum 20 can be through printing technology shaping, make the reflection stratum 20 can the large tracts of land shaping, and one shot press forming is a plurality of ultrasonic fingerprint module 100 to obtain ultrasonic fingerprint module 100 in batches after cutting out, improve production efficiency. Specifically, at first the ultrasonic detection layer 10 of shaping large tracts of land, then print the reflecting layer 20 of shaping large tracts of land on the ultrasonic detection layer 10 of large tracts of land, then cut out the ultrasonic detection layer 10 of large tracts of land and the reflecting layer 20 of large tracts of land together and form a plurality of ultrasonic fingerprint modules 100, realize ultrasonic fingerprint module 100 and put into production in batches fast, reduction in production cost, raise the efficiency.

Further, the reflective layer 20 is formed by adding carbon powder particles to a resin material, so that the reflective layer 20 exhibits a black appearance effect.

In this embodiment, a resin material and carbon powder are mixed to form liquid ink, and then the liquid ink is formed on the ultrasonic fingerprint detection layer 10 by a screen printing process and cured to form the reflection layer 20. The elastic modulus of the reflective layer 20 is determined according to the frequency of the ultrasonic waves emitted from the ultrasonic detection layer 10, so that the elastic modulus of the reflective layer 20 matches the frequency of the ultrasonic waves. Through setting up the elastic modulus of reflection stratum 20 for reflection stratum 20 can keep out and reflect ultrasonic signal, in order to realize the fingerprint identification efficiency of ultrasonic fingerprint module 100 improves. The reflecting layer 20 has a black appearance visual effect due to the fact that the reflecting layer 20 contains black carbon powder, so that the reflecting layer 20 can block visible light from penetrating, namely the reflecting layer 20 can cover the ultrasonic fingerprint detection layer 10, appearance defects of the ultrasonic fingerprint detection layer 10 are not visible, and the appearance performance of the ultrasonic fingerprint module 100 is improved. The reflective layer 20 may be formed by printing a liquid printing material to form a layer structure and then performing a curing process. Specifically, first, a liquid resin material and a black carbon powder material mixed with the liquid resin material are provided. Then, a liquid resin material mixed with a black carbon powder material is printed and molded on the bottom surface 12 of the detection layer of the ultrasonic detection layer 10 by a printing device. Finally, the liquid reflective layer 20 in a layered structure is cured to obtain a solid reflective layer 20. Of course, in other embodiments, the reflective layer 20 may be made of white carbon powder, red carbon powder, or green carbon powder mixed with insulating paste. The reflective layer 20 may be made of other materials with ultrasonic wave shielding property mixed with colored particles. Of course, in other embodiments, the reflective layer 20 may also be a transparent layer, so that the ultrasonic fingerprint module 100 is integrated in a display screen, and the display effect of the display screen is ensured.

In this embodiment, the carbon powder particles in the reflective layer 20 can fill gaps between resin particles in the resin material, so that the surface roughness of the reflective layer 20 is reduced, and the surface of the reflective layer 20 is smooth.

In particular, the reflective layer 20 has a first surface 201 remote from the fingerprint detection layer 10. The first surface 201 is in contact with air. The first surface 201 is smoothly arranged, and the roughness of the first surface 201 is 0.2 Rz/mum-6.0 Rz/mum. For example, the roughness of the first surface 201 may be 0.41Rz/μm, or 0.68Rz/μm, or 4.76Rz/μm, or 5.25Rz/μm. The reflective layer 20 has a second surface 202 opposite the first surface 201. The second surface 202 is attached to the fingerprint detection layer 10. The second surface 202 is smoothly arranged, and the roughness of the second surface is 0.2Rz/μm to 6.0Rz/μm. For example, the roughness of the first surface 201 may be 0.41Rz/μm, or 0.68Rz/μm, or 4.76Rz/μm, or 5.25Rz/μm. The smaller the roughness of the first surface 201 is, the smaller the degree of unevenness of the first surface 201 is, that is, the smoother the first surface is, the less diffuse reflection of the ultrasonic wave is generated on the first surface 201, the more consistent the reflection direction of the ultrasonic wave on the first surface 201 tends to be, the smaller the ultrasonic interference signal received by the ultrasonic detection layer 10 is, and the fingerprint identification definition of the ultrasonic fingerprint module 100 is improved. Similarly, the smaller the roughness of second surface 202, the ultrasonic wave is in the process second surface 202 is difficult diffuse reflection more, has improved ultrasonic fingerprint module 100's fingerprint identification efficiency.

It is understood that the larger the average particle size of the carbon powder particles in the reflective layer 20, the more easily the roughness of the first surface 201 and the roughness of the second surface 202 of the reflective layer 20 are increased, the more easily the first surface 201 forms a diffuse reflection to the ultrasonic waves, and the more easily the second surface 202 forms a diffuse reflection to the ultrasonic waves. Therefore, by setting the average particle size of the carbon powder particles in the reflective layer 20 and setting the proportion of the carbon powder particles in the reflective layer 20, the roughness of the first surface 201 and the roughness of the second surface 202 can be improved.

In the present embodiment, the average particle diameter of the carbon powder particles in the reflective layer 20 is 0.5 to 5 micrometers. When the average particle size of the carbon powder particles in the reflective layer 20 is 0.5 μm, the roughness of the reflective layer 20 can be minimized, but the OD of the ultrasonic fingerprint module 100 is not optimal. When the average particle size of the carbon powder particles in the reflective layer 20 is 5 micrometers, the OD value of the ultrasonic fingerprint module 100 is excellent, but the roughness of the reflective layer 20 is not optimal. In a preferred embodiment, the average particle size of the carbon powder particles in the reflective layer 20 is 0.8 microns to 2 microns, and more preferably 1.0 micron. It can be understood that, when the average particle size of the carbon powder particles of the reflective layer 20 is 0.8 μm, the roughness of the reflective layer 20 can be similar to the minimum value, and the OD value of the ultrasonic fingerprint module 100 meets the performance requirement. When the average particle size of the carbon powder particles of the reflective layer 20 is 2 micrometers, the OD value of the ultrasonic fingerprint module 100 is excellent, and the roughness of the reflective layer 20 can be reduced. Furthermore, when the average particle size of the carbon powder particles of the reflective layer 20 is 1 μm, the roughness of the reflective layer 20 can be similar to the minimum value, and both the OD value and the SNR value of the ultrasonic fingerprint module 100 can be excellent. Of course, the average particle diameter of the carbon powder particles in the reflective layer 20 may also be approximately 1 micron, the roughness of the reflective layer 20 may be similar to the minimum value, and the OD value and SNR value of the ultrasonic fingerprint module 100 may also be excellent.

In the present embodiment, the mass ratio of the carbon powder particles in the reflective layer 20 is 2.5% to 15%. When the mass ratio of the carbon powder particles in the reflective layer 20 is 2.5%, the roughness of the reflective layer 20 can be minimized, but the OD value of the ultrasonic fingerprint module 100 is not optimal. When the mass ratio of the carbon powder particles in the reflective layer 20 is 15%, the OD value of the ultrasonic fingerprint module 100 is high, but the roughness of the reflective layer 20 is not the minimum. In a preferred embodiment, the ratio of the carbon powder particles in the reflective layer is 3.0% to 10%, and more preferably 5%. It can be understood that when the mass percentage of the carbon powder particles in the reflective layer 20 is 3.0%, the roughness of the reflective layer 20 can be similar to the minimum value, and the OD value of the ultrasonic fingerprint module 100 meets the performance requirement. When the mass ratio of the carbon powder particles in the reflective layer 20 is 10%, the OD value of the ultrasonic fingerprint module 100 meets the requirement, and the roughness of the reflective layer 20 can be reduced. Furthermore, when the mass percentage of the carbon powder particles in the reflective layer 20 is 5%, the roughness of the reflective layer 20 can be similar to the minimum value, and both the OD value and the SNR value of the ultrasonic fingerprint module 100 can be excellent. Of course, the mass ratio of the carbon powder particles in the reflective layer 20 may be approximately 5%, the roughness of the reflective layer 20 may be approximately the minimum value, and the OD value and the SNR value of the ultrasonic fingerprint module 100 may also be excellent.

In order to further improve the roughness of said first surface 201 and the roughness of said second surface 202. The leveling agent is added in the preparation process of the reflecting layer 20, so that the surface roughness of the reflecting layer 20 is effectively reduced by utilizing the performances of surface defoaming, surface leveling control and better surface leveling property of the leveling agent. That is, the reflective layer 20 further contains a leveling agent for improving the leveling property of the reflective layer during the manufacturing process and the final formation. The mass ratio of the leveling agent in the reflective layer 20 may be 0.2% to 1.5%. When the mass percentage of the leveling agent in the reflective layer is 0.2%, the surface leveling property of the reflective layer 20 can be effectively improved, and the reduction of the surface roughness of the reflective layer 20 is primarily achieved. Under the condition that the type of the leveling agent is single, when the mass ratio of the leveling agent to the reflective layer is 1.5%, the surface stability of the reflective layer 20 can be effectively improved, and further the surface roughness of the reflective layer 20 can be effectively reduced, but the OD value of the ultrasonic fingerprint module 100 is not preferable, that is, the surface roughness of the reflective layer 20 and the mass ratio of the leveling agent to the reflective layer 20 are in a positive relationship, and the OD value of the ultrasonic fingerprint module 100 and the mass ratio of the leveling agent to the reflective layer 20 are in a negative relationship. The flatting agent comprises a fluorocarbon flatting agent so as to ensure the substrate wettability and the anti-cratering capacity of the reflecting layer. The fluorocarbon leveling agent is fluorocarbon organic modified siloxane. As a preferred embodiment, the levelling agent further comprises a polyether siloxane copolymer. Namely, the leveling agent is a mixture of fluorocarbon organic modified siloxane and polyether siloxane copolymer. The mass ratio of the fluorocarbon organic modified siloxane in the reflecting layer 20 can be 0.1-0.75%, and the mass ratio of the polyether siloxane copolymer in the reflecting layer 20 can be 0.1-0.75%. The mass ratio of the fluorocarbon organic siloxane in the reflecting layer 20 is 0.1%, and the mass ratio of the polyether siloxane copolymer in the reflecting layer 20 is 0.1%, that is, the mass ratio of the leveling agent in the reflecting layer 20 is 0.2%, so that the surface roughness of the reflecting layer 20 can be reduced primarily, and the fluorocarbon organic siloxane is effectively complementary with the polyether siloxane copolymer, so that the surface stability of the reflecting layer 20 can be further improved. The mass ratio of the fluorocarbon organic siloxane in the reflection layer 20 is 0.75%, the mass ratio of the polyether siloxane copolymer in the reflection layer 20 is 0.75%, namely the mass ratio of the leveling agent in the reflection layer 20 is 1.5%, the surface roughness of the reflection layer 20 is greatly reduced, and the SNR value and the OD value of the ultrasonic fingerprint module 100 are also effectively improved.

Preferably, the ratio of the fluorocarbon organic modified siloxane to the reflecting layer is 0.2% to 0.6%, and more preferably 0.5% by mass. When the mass ratio of the polyether siloxane copolymer is 0.2-0.6%, and more specifically 0.5%, the leveling agent has the best control force on the surface stability of the reflective layer 20, so that the roughness of the reflective layer 20 can be greatly reduced, and the SNR value and the OD value of the ultrasonic fingerprint module can be further increased. It can be understood that the polyether siloxane copolymer and the fluorocarbon siloxane have good complementarity, the polyether siloxane copolymer has strong surface state control capability and good surface leveling property, and simultaneously has a certain defoaming effect. The leveling property of the reflecting layer 20 is good, the surface is smooth, the surface roughness can be controlled to be less than or equal to 0.5 Rz/mum, and the fingerprint identification efficiency of the ultrasonic fingerprint module 100 is improved.

In the first embodiment, the reflective layer 20 is provided with a mean particle size of 5 μm at 50% of the particle size distribution of the carbon powder particles. The mass percentage of carbon powder in the reflecting layer 20 is 15%. The leveling agent in the reflective layer 20 is fluorocarbon organic modified siloxane. The mass ratio of the leveling agent in the reflecting layer 20 is 0.2%. The roughness tester is used to test the roughness of the reflective layer 20 of the ultrasonic fingerprint module 100 in this embodiment, and the test result shows that the roughness of the reflective layer 20 is 5.25Rz/μm. Adopt ultrasonic fingerprint function tester to carry out SNR value test to ultrasonic fingerprint module 100 in this embodiment, it is 9.45 to obtain the SNR value. An Optical Density (OD) value of the ultrasonic fingerprint module 100 in this embodiment is measured by an optical density meter, and the OD value is 6.1.

A second embodiment is provided, which is different from the first embodiment in that the mass ratio of the carbon powder in the reflective layer 20 is reduced. The reflective layer 20 is provided with carbon powder particles having an average particle size of 5 μm at 50% of the particle size distribution. The mass percentage of the carbon powder in the reflecting layer 20 is 10%. The leveling agent in the reflective layer 20 is fluorocarbon organic modified siloxane. The mass ratio of the leveling agent in the reflecting layer 20 is 0.2%. The roughness of the reflective layer 20 was 5.04 Rz/. mu.m. The SNR value of the ultrasonic fingerprint module 100 is 9.52. The OD value of the ultrasonic fingerprint module 100 is 5.3. It can be seen that the surface roughness of the reflective layer 20 can be reduced by reducing the carbon powder ratio of the reflective layer 20.

It can be understood that, when the OD value of the ultrasonic fingerprint module 100 is greater than 4, the performance of the ultrasonic fingerprint module 100 is better.

A third embodiment is provided, which is different from the second embodiment in that the mass ratio of the carbon powder in the reflective layer 20 is continuously decreased. The reflective layer 20 is provided with carbon powder particles having an average particle size of 5 μm at 50% of the particle size distribution. The mass percentage of the carbon powder in the reflecting layer 20 is 5%. The leveling agent in the reflective layer 20 is fluorocarbon organic modified siloxane. The mass ratio of the leveling agent in the reflecting layer 20 is 0.2%. The roughness of the reflective layer 20 was 4.76 Rz/. mu.m. The SNR value of the ultrasonic fingerprint module 100 is 9.65. The OD value of the ultrasonic fingerprint module 100 is 4.6. It can be seen that, although the mass fraction of the carbon powder in the reflective layer 20 is reduced, the surface roughness of the reflective layer 20 can be reduced, and the SNR value of the ultrasonic fingerprint module 100 is improved, the OD value of the ultrasonic fingerprint module 100 is also reduced.

A fourth embodiment is provided, which is different from the third embodiment in that the mass ratio of the carbon powder in the reflective layer 20 is continuously decreased. The reflective layer 20 is provided with carbon powder particles having an average particle size of 5 μm at 50% of the particle size distribution. The mass percentage of the carbon powder in the reflecting layer 20 is 2.5%. The leveling agent in the reflective layer 20 is fluorocarbon organic modified siloxane. The mass ratio of the leveling agent in the reflecting layer 20 is 0.2%. The roughness of the reflective layer 20 was 4.42Rz/μm. The SNR value of the ultrasonic fingerprint module 100 is 9.7. The OD value of the ultrasonic fingerprint module 100 is 3.7. It can be seen that when the mass ratio of the carbon powder in the reflective layer 20 is reduced to 2.5%, the OD value of the ultrasonic fingerprint module 100 is also reduced to 3.7, and the ultrasonic fingerprint module 100 does not meet the requirement of good performance.

A fifth embodiment is provided, which is different from the fourth embodiment in that the average particle size of the carbon powder in the reflective layer 20 is reduced. The average particle diameter of 50% of the particle size distribution of the carbon powder particles of the reflective layer 20 is 0.5 μm. The average particle size of 100% of the particle size distribution of the carbon powder particles of the reflecting layer 20 is less than 1 μm. The mass percentage of the carbon powder in the reflecting layer 20 is 5%. The leveling agent in the reflective layer 20 is fluorocarbon organic modified siloxane. The mass ratio of the leveling agent in the reflecting layer 20 is 0.2%. The roughness of the reflective layer 20 was 0.82 Rz/. mu.m. The SNR value of the ultrasonic fingerprint module 100 is 10.25. The OD value of the ultrasonic fingerprint module 100 is 4.3. It can be seen that, when the average particle size of carbon powder in the reflective layer 20 is reduced, the surface roughness of the reflective layer 20 can be significantly reduced, and it can be ensured that the SNR value of the ultrasonic fingerprint module 100 is higher, and the OD value of the ultrasonic fingerprint module 100 also meets the requirement of good performance, that is, the performance of the ultrasonic fingerprint module 100 is significantly improved.

A sixth embodiment is provided, which is different from the fifth embodiment in that the ratio of the leveling agent in the reflective layer 20 is increased. The average particle diameter of 50% of the particle size distribution of the carbon powder particles of the reflective layer 20 is 0.5 μm. The average particle size of 100% of the particle size distribution of the carbon powder particles of the reflecting layer 20 is less than 1 μm. The mass percentage of the carbon powder in the reflecting layer 20 is 5%. The leveling agent in the reflective layer 20 is fluorocarbon organic modified siloxane. The mass ratio of the leveling agent in the reflecting layer 20 is 0.7%. The roughness of the reflective layer 20 was 0.68Rz/μm. The SNR value of the ultrasonic fingerprint module 100 is 10.35. The OD value of the ultrasonic fingerprint module 100 is 4.4. It can be seen that when the mass fraction of the leveling agent in the reflective layer 20 is increased, the surface roughness of the reflective layer 20 is also decreased, and the SNR value of the ultrasonic fingerprint module 100 is increased. The OD value of the ultrasonic fingerprint module 100 is also increased.

A seventh embodiment is provided, which is different from the sixth embodiment in that the leveling agent in the reflective layer 20 is a mixture of two different types of leveling agents. Specifically, the average particle size of 50% of the particle size distribution of the carbon powder particles of the reflective layer 20 is 0.5 μm. The average particle size of 100% of the particle size distribution of the carbon powder particles of the reflecting layer 20 is less than 1 μm. The mass percentage of the carbon powder in the reflecting layer 20 is 5%. The leveling agent in the reflecting layer 20 is a mixed leveling agent of fluorocarbon organic modified siloxane and polyether siloxane copolymer. The mass ratio of the fluorocarbon organic modified siloxane in the reflecting layer 20 is 0.5%. The mass ratio of the polyether siloxane copolymer in the reflecting layer 20 is 0.5%. The roughness of the reflective layer 20 was 0.41Rz/μm. The SNR value of the ultrasonic fingerprint module 100 is 10.55. The OD value of the ultrasonic fingerprint module 100 is 4.3. Therefore, the fluorocarbon organic modified siloxane belongs to a fluorocarbon leveling agent, has good substrate wettability and strong anti-shrinkage capacity, but the leveling agent is easy to stabilize bubbles and is difficult to foam. By adding various leveling agents into the molding material of the reflecting layer 20, the polyether siloxane copolymer and the fluorocarbon siloxane are found to have better complementarity, the polyether siloxane copolymer has strong surface state control capability and good surface leveling property, and simultaneously has a certain defoaming effect. After the polyether siloxane copolymer and the fluorocarbon siloxane are added into the forming material of the reflecting layer 20, the leveling property is good, the surface is smooth, and the surface roughness of the reflecting layer 20 can be controlled to be less than 0.5 Rz/mum.

It can be understood that, if the reflecting layer 20 has bubbles, the ultrasonic acoustic impedance of the bubbles is very small, so that the signal intensity is greatly attenuated or even not reduced when the ultrasonic signal penetrates through and reflects the bubbles, that is, the signal receiving intensity of the ultrasonic detection layer 10 at the position corresponding to the bubbles in the reflecting layer 20 is obviously different from that of other areas, which causes noise in the acquired fingerprint image, that is, the acquired fingerprint image is unclear. Therefore, by improving the bubbles in the reflective layer 20, the sharpness of the fingerprint image acquired by the ultrasonic fingerprint module 100 can be improved.

In order to further reduce the number of bubbles in the reflective layer 20. The defoaming agent is added into the molding material of the reflective layer 20 to reduce the number of bubbles in the reflective layer 20 by utilizing the defoaming performance of the defoaming agent. That is, the reflective layer 20 further contains an antifoaming agent for removing bubbles of the reflective layer during the manufacturing process and removing bubbles of the reflective layer finally formed. The mass ratio of the defoaming agent in the reflective layer 20 may be 1.0% to 3.0%. The defoamer can be modified dimethylsilane, and the defoamer can also be polyoxypropylene ethylene oxide glycerol ether. As a preferred embodiment, the defoamer may be a mixture of modified dimethylsilane and polyoxypropylene oxyethylene glyceryl ether. The mass ratio of the modified dimethylsilane may be 0.8 to 2.0%, and the mass ratio of the polyoxypropylene oxyethylene glycerin ether may be 0.2 to 1.0%. When the mass ratio of the fluorocarbon organic modified siloxane is 1.5% and the mass ratio of the polyether siloxane copolymer is 0.5% -1.0%, the reflecting layer 20 has no bubbles.

An eighth embodiment is provided where the reflective layer 20 is provided with an anti-foaming agent. Specifically, the mass percentage of the carbon powder in the reflective layer 20 is 15%. The defoaming agent in the reflective layer 20 is modified dimethylsilane. The weight ratio of the defoaming agent in the reflective layer 20 was 0.5%. A defoaming agent is added into the forming material of the reflecting layer 20, a large amount of bubbles exist after stirring, and after the forming material of the reflecting layer 20 after stirring is printed and formed on the fingerprint detection layer 10 through a screen printing process, a large amount of bubbles still exist in the reflecting layer 20. The OD value of the ultrasonic fingerprint module 100 is 6.1.

In the ninth embodiment, unlike the eighth embodiment, the mass ratio of the carbon powder in the reflective layer 20 is reduced, and the mass ratio of the defoaming agent in the reflective layer 20 is increased. Specifically, the mass percentage of the carbon powder in the reflective layer 20 is 10%. The defoaming agent in the reflective layer 20 is modified dimethylsilane. The weight ratio of the defoaming agent in the reflective layer 20 was 0.8%. The defoaming agent is added into the forming material of the reflecting layer 20, a small amount of bubbles exist after stirring, and after the forming material of the reflecting layer 20 after stirring is printed and formed on the fingerprint detection layer 10 through a screen printing process, a small amount of bubbles still exist in the reflecting layer 20. The OD value of the ultrasonic fingerprint module 100 is 5.3. It can be seen that the higher the mass fraction of the carbon powder in the reflective layer 20, the more likely the reflective layer 20 is to generate bubbles during the manufacturing process. The bubble content in the reflective layer 20 can be improved by decreasing the mass ratio of the carbon powder in the reflective layer 20 and increasing the mass ratio of the defoaming agent in the reflective layer 20.

A tenth embodiment is provided, and different from the ninth embodiment, the mass ratio of the carbon powder in the reflective layer 20 is continuously decreased, and the mass ratio of the defoaming agent in the reflective layer 20 is continuously increased. Specifically, the mass percentage of the carbon powder in the reflective layer 20 is 5%. The defoaming agent in the reflective layer 20 is modified dimethylsilane. The weight ratio of the defoaming agent in the reflective layer 20 was 1.5%. There are few bubbles after the shaping material of reflector layer 20 has added the defoaming agent stirring, will shaping material after the reflector layer 20 stirring is through screen printing technology printing shaping in behind fingerprint detection layer 10, there are still a small amount of bubbles in reflector layer 20. The OD value of the ultrasonic fingerprint module 100 is 4.6. It can be seen that by reducing the carbon powder ratio in the reflective layer 20 and increasing the mass ratio of the defoaming agent in the reflective layer 20, the bubble content in the reflective layer 20 can be obviously improved, but the OD value of the ultrasonic fingerprint module 100 can also be obviously reduced, which easily causes the performance reduction of the ultrasonic fingerprint module 100.

In the eleventh embodiment, unlike the tenth embodiment, the mass ratio of the carbon powder in the reflective layer 20 is continuously decreased, and the mass ratio of the defoaming agent in the reflective layer 20 is continuously increased. Specifically, the mass ratio of the carbon powder in the reflecting layer 20 is 2.5%. The defoaming agent in the reflective layer 20 is modified dimethylsilane. The weight ratio of the defoaming agent in the reflective layer 20 was 2.0%. There are few bubbles after the shaping material of reflector layer 20 has added the defoaming agent stirring, will shaping material after the reflector layer 20 stirring is through screen printing technology printing shaping in behind fingerprint detection layer 10, there are still a small amount of bubbles in reflector layer 20. The OD value of the ultrasonic fingerprint module 100 is 3.7. When the mass ratio of the defoaming agent in the reflective layer 20 is 2.0%, shrinkage cavities are conspicuously formed in the reflective layer 20. It can be seen that the reflective layer 20 cannot meet the use requirement when the mass ratio of the defoaming agent in the reflective layer 20 is greater than 2.0%. The mass ratio of the carbon powder in the reflective layer 20 is greater than or equal to 5%, and the mass ratio of the defoaming agent in the reflective layer 20 is increased to approximately 1.5%, so that the OD value of the ultrasonic fingerprint module 100 can meet the minimum requirement, but it is still impossible to ensure that the reflective layer 20 is bubble-free.

A twelfth embodiment is provided that differs from the eleventh embodiment in that the defoamer in the reflective layer 20 comprises two different types of defoamers. Specifically, the mass percentage of the carbon powder in the reflective layer 20 is 5%. The defoaming agent in the reflective layer 20 is a mixture of modified dimethylsilane and polyoxypropylene ethylene oxide glyceryl ether. The mass ratio of the modified dimethylsilane in the reflecting layer 20 is 1.5%. The ratio of the polyoxypropylene ethylene oxide glycerin ether in the reflective layer 20 was 0.2% by mass. The foam-free after the defoaming agent is added into the forming material of the reflecting layer 20 and stirred, the forming material after the reflecting layer 20 is stirred is printed and formed on the back of the fingerprint detection layer 10 through a screen printing process, and a very small amount of bubbles still exist in the reflecting layer 20. The OD value of the ultrasonic fingerprint module 100 is 4.5. It can be seen that, because the defoaming agent in the reflective layer 20 contains modified dimethylsilane and polyoxypropylene ethylene oxide glyceryl ether, the bubble content of the reflective layer 20 during the preparation process can be obviously improved, and the OD value of the ultrasonic fingerprint module 100 also meets the performance requirements, but a very small amount of bubbles still exist in the reflective layer 20 after the final molding.

A thirteenth embodiment is provided, which is different from the twelfth embodiment in that the mass ratio of polyoxypropylene oxyethylene glycerin ether is increased in the molding material of the reflective layer 20. Specifically, the mass percentage of the carbon powder in the reflective layer 20 is 5%. The defoaming agent in the reflective layer 20 is a mixture of modified dimethylsilane and polyoxypropylene ethylene oxide glyceryl ether. The mass ratio of the modified dimethylsilane in the reflecting layer 20 is 1.5%. The ratio of the polyoxypropylene ethylene oxide glycerin ether in the reflective layer 20 was 0.5% by mass. The forming material of the reflecting layer 20 is added with the defoaming agent and is stirred to be free of bubbles, the forming material after stirring of the reflecting layer 20 is printed and formed on the fingerprint detection layer 10 through a screen printing process, and the reflecting layer 20 is free of bubbles. The OD value of the ultrasonic fingerprint module 100 is 4.6. It can be seen that, through the fact that the defoaming agent in the reflection layer 20 contains modified dimethylsilane and polyoxypropylene ethylene oxide glyceryl ether, and the mass ratio of the polyoxypropylene ethylene oxide glyceryl ether is increased, no bubble can be generated in the reflection layer 20 in the preparation process, the reflection layer 20 which is finally formed has no bubble, the OD value of the ultrasonic fingerprint module 100 also meets the performance requirement, and the performance of the ultrasonic fingerprint module 100 is obviously improved.

A fourteenth embodiment is provided, which is different from the thirteenth embodiment in that the mass ratio of polyoxypropylene oxyethylene glycerin ether in the reflective layer 20 is continuously increased. Specifically, the mass percentage of the carbon powder in the reflective layer 20 is 5%. The defoaming agent in the reflective layer 20 is a mixture of modified dimethylsilane and polyoxypropylene ethylene oxide glyceryl ether. The mass ratio of the modified dimethylsilane in the reflecting layer 20 is 1.5%. The ratio of the polyoxypropylene ethylene oxide glycerin ether in the reflective layer 20 was 1.0% by mass. The forming material of the reflecting layer 20 is added with the defoaming agent and is stirred to be free of bubbles, the forming material after stirring of the reflecting layer 20 is printed and formed on the fingerprint detection layer 10 through a screen printing process, and the reflecting layer 20 is free of bubbles. The OD value of the ultrasonic fingerprint module 100 is 4.6.

Further, referring to fig. 2, the ultrasonic detection layer 10 includes a substrate layer 13, a plurality of pixel electrodes 14, a piezoelectric layer 15 and a conductive electrode 16, the plurality of pixel electrodes 14 are arranged in the substrate layer 13 in an array, the piezoelectric layer 15 covers the plurality of pixel electrodes 14, the conductive electrode 16 is laminated on a surface of the piezoelectric layer 15 away from the plurality of pixel electrodes 14, and the reflective layer 20 is formed by printing on a surface of the conductive electrode 16 away from the piezoelectric layer 15.

In this embodiment, the base material layer 13 may be made of glass or a polyimide film material. Substrate layer 13's cost is lower, the light transmissivity is better, and is convenient ultrasonic wave fingerprint module 100 is integrated in electronic equipment's display screen. When ultrasonic fingerprint module 100 is integrated in the display screen, the ultrasonic fingerprint module 100 that has better light transmissivity can not shelter from display screen 90's display image, and ultrasonic fingerprint module 100 integrated in display screen 90 simultaneously can keep display screen 90's whole colour unanimous and improve display screen 90's appearance quality.

In this embodiment, the pixel electrodes 14 may be formed on the substrate layer 13 by a TFT printing process and distributed in an array. The pixel electrode 14 is made of any one of Indium Tin Oxide (ITO), nano silver wire (silver wire), metal mesh (metal mesh), carbon nanotube, and Graphene (Graphene), and the pixel electrode 14 made of the above materials has good toughness and light transmittance. So that the ultrasonic fingerprint module 100 made of the pixel electrode 14 has better toughness and light transmittance. The light transmittance of the pixel electrode 14 is greater than 90%, so that the ultrasonic fingerprint module 100 made of the pixel electrode 14 has better light transmittance. The pixel electrodes 14 can be used for receiving electric signals, each pixel electrode 14 can determine a position of the ultrasonic fingerprint module 100 according to the received electric signals, and the density of the pixel electrodes 14 on the substrate layer 13 is positively correlated with the fingerprint collection precision of the ultrasonic fingerprint module 100. The density of the array arrangement of the pixel electrodes 14 ensures the accuracy of the fingerprint image of the object to be detected by the ultrasonic sensor.

In the present embodiment, the ultrasonic wave receiving surface 11 is provided on the piezoelectric layer 15 on the side facing the base material layer 13. The piezoelectric layer 15 is laminated on the base material layer 13 and covers the plurality of pixel electrodes 14. The piezoelectric layer 15 is a sheet structure made of piezoelectric material. The shape of the piezoelectric layer 15 matches the shape of the substrate layer 13. The material of the piezoelectric layer 15 is Polyvinylidene fluoride (PVDF). Because polyvinylidene fluoride has better toughness and light transmissivity, make piezoelectric layer 15 has better pliability and light transmissivity, has guaranteed ultrasonic fingerprint module 100's pliability and light transmissivity. The piezoelectric layer 15 is capable of generating ultrasonic waves under the action of a high-frequency voltage (for example, a voltage with a frequency greater than 20 KHZ). After the piezoelectric layer 15 receives the ultrasonic wave reflected by the object to be detected, the piezoelectric layer 15 generates an electric signal (or a piezoelectric signal) under the action of the ultrasonic wave, and the object to be detected can be a finger, a test template and the like.

In this embodiment, the conductive electrode 16 is an integral layered structure made of a conductive material. The shape of the conductive electrode 16 matches the shape of the piezoelectric layer 15. The material of the conductive electrode 16 may be silver material. The conductive electrode 16 may be formed after silver paste is cured. The light transmittance of the conductive electrode 16 is greater than 90%. After the conductive electrode 16 and the pixel electrode 14 are energized with a high frequency voltage, the high frequency voltage can be applied to the piezoelectric layer 15, so that the piezoelectric layer 15 generates an ultrasonic signal to detect a user fingerprint by using the ultrasonic signal. The conductive electrode 16 and the pixel electrode 14 can also receive an electrical signal generated by the piezoelectric layer 15. The bottom surface 12 of the detection layer is disposed on a surface of the conductive electrode 16 away from the piezoelectric layer 15. The reflective layer 20 covers the conductive electrode 16, and can prevent the conductive electrode 16 from being oxidized. The reflective layer 20 may also mask cosmetic defects on the conductive electrode 16.

In this embodiment, the thickness of the conductive electrode 16 is 10 to 30 micrometers, the thickness of the piezoelectric layer 15 is 5 to 15 micrometers, and the thickness of the base material layer 13 is 80 to 100 micrometers. The reflective layer 20 has a thickness of 7 to 30 micrometers. Utilize the thin performance of ultrasonic fingerprint module 100 is convenient ultrasonic fingerprint module 100 is integrated in electronic equipment's display screen.

It is understood that the reflective layer 20 is printed on the fingerprint detection layer 10, i.e. the reflective layer 20 is printed on the conductive electrode 16. The surface roughness of the conductive electrode 16 has an effect on the roughness of the first surface 201 of the reflective layer 20.

After testing, the reflective layer 20 with different thicknesses is formed on the glass substrate with smaller surface roughness, and the surface roughness of the formed reflective layer 20 is measured, it is found that the surface roughness of the formed reflective layer 20 is not greatly influenced by the thickness of the reflective layer 20. For example, the reflective layers 20 having film thicknesses of 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, and 30 μm are formed on the glass substrate, and the surface roughness of the reflective layers 20 after forming is 0.375Rz/μm, 0.355Rz/μm, 0.335Rz/μm, 0.315Rz/μm, 0.316Rz/μm, and 0.322Rz/μm, respectively.

After testing, a plurality of reflection layers 20 with different thicknesses are respectively formed on a plurality of fingerprint detection layers 10, and finally a plurality of ultrasonic fingerprint modules 100 are obtained, and the surface roughness of the reflection layer 20 of the ultrasonic fingerprint module 100 is measured, and it is found that the thicker the thickness of the reflection layer 20 is, the smaller the surface roughness of the reflection layer 20 is, and when the thickness of the reflection layer 20 is about 25 μm, the surface roughness of the reflection layer 20 is not reduced along with the reduction of the thickness of the reflection layer 20, that is, the surface roughness of the reflection layer 20 tends to be stable and not reduced any more.

In one embodiment, six of the fingerprint detection layers 10 are arranged to have a surface roughness of 3.5Rz/μm to 4.5Rz/μm towards the reflective layer 20. The thickness of the substrate layer 13 in the six fingerprint detection layers 10 is 90 μm, the thickness of the piezoelectric layer 15 is 9 μm, and the thickness of the conductive electrode 16 is 15-18 μm. Six reflection layers 20 having film thicknesses of 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, and 30 μm are respectively formed on the six fingerprint detection layers 10, and the surface roughness of the six formed reflection layers 20 is detected to be 1.712Rz/μm, 1.06Rz/μm, 0.72Rz/μm, 0.527Rz/μm, 0.309Rz/μm, and 0.324Rz/μm, respectively. Obviously, when the thickness of the reflective layer 20 is 20 μm to 30 μm, the surface roughness of the reflective layer 20 of the ultrasonic fingerprint module 100 is small, and the performance of the ultrasonic fingerprint module 100 is excellent.

In another embodiment, as shown in FIG. 3, the reflective layer 20 is provided with a plurality of sub-reflective layers 22, and the plurality of sub-reflective layers 22 are sequentially stacked in a reflective manner.

In this embodiment, the reflective layer 20 is formed by a plurality of printing steps, and each of the sub-reflective layers 22 is formed in each printing step. After each sub-reflective layer 22 is cured, another sub-reflective layer 22 is formed. The thickness of each of the sub-reflective layers 22 may be set to be the same. By precisely controlling the surface roughness of each sub-reflecting layer 22, the surface roughness of the finally molded reflecting layer 20 is more excellent, so as to ensure that the performance of the ultrasonic fingerprint module 100 is excellent.

Referring to fig. 4, the present application provides a method for manufacturing an ultrasonic fingerprint module, including the steps of:

101: an ultrasonic detection layer 10 is provided.

In the present embodiment, first, the base layer 13 is molded. The substrate layer 13 may be made of glass or a polyimide film material. The substrate layer 13 has good mechanical strength, so that other structural components can be conveniently formed on the substrate layer 13, and the ultrasonic fingerprint film 100 can be conveniently and stably connected with a shell of an electronic device or the back of a display screen of the electronic device. The length and width of the substrate layer 13 can be designed according to the required length and width of the ultrasonic fingerprint module 100, so that the length and width of the ultrasonic fingerprint module 100 can meet the specification requirement.

Then, a pixel electrode layer is formed on the base material layer 13. The pixel electrode layer is constituted by a plurality of pixel electrodes 14. The length and width of the pixel electrode layer are substantially the same as those of the base material layer 13. The plurality of pixel electrodes 14 of the pixel electrode layer may be formed on the substrate layer 13 through a TFT printing process. The pixel electrode 14 is made of any one of Indium Tin Oxide (ITO), nano silver wire (silver wire), metal mesh (metal mesh), carbon nanotube, and Graphene (Graphene), and the pixel electrode 14 made of the above materials has good toughness and light transmittance.

Then, a piezoelectric layer 15 is formed on the pixel electrode layer. The piezoelectric layer 15 has a length and a width substantially equal to those of the pixel electrode layer. The piezoelectric layer 15 covers the plurality of pixel electrodes 14. The piezoelectric layer 15 is a sheet structure made of piezoelectric material. The shape of the piezoelectric layer 15 matches the shape of the substrate layer 13. The material of the piezoelectric layer 15 is Polyvinylidene fluoride (PVDF). Because polyvinylidene fluoride has better toughness and light transmissivity, make piezoelectric layer 15 has better pliability and light transmissivity, has guaranteed ultrasonic fingerprint module 100's pliability and light transmissivity.

Then, a conductive electrode 16 is formed on the piezoelectric layer 15. The length and width of the conductive electrode 16 are the same as those of the pixel electrode layer, so that the conductive electrode 16 is matched with the pixel electrode layer. The conductive electrode 16 may be formed on the piezoelectric layer 15 by a screen printing process. The conductive electrode 16 is an integral layered structure made of a conductive material. The shape of the conductive electrode 16 matches the shape of the piezoelectric layer 15. The material of the conductive electrode 16 may be silver material. The conductive electrode 16 may be formed after silver paste is cured. Two or more layers of the conductive electrodes 16 may be formed on the piezoelectric layer 15, so that the surface roughness of the outermost layer of the conductive electrodes 16 away from the piezoelectric layer 15 is smaller, i.e. the bottom surface of the detection layer of the ultrasonic detection layer 10 is smoother.

102: a liquid ink material containing a leveling agent is provided.

In this embodiment, the liquid ink material further contains a resin material and carbon powder particles. The resin material can be any one of acrylic resin, polyester resin, isocyanate resin, phenoxy resin and epoxy resin or a plurality of combined resin materials. As a better embodiment, the liquid ink material is formed by mixing and stirring epoxy resin and carbon powder particles.

Further, the liquid ink material further contains a defoaming agent. Namely, the epoxy resin, the carbon powder particles, the defoaming agent and the flatting agent are mixed and stirred to form the liquid ink material.

The liquid ink material containing the defoaming agent can effectively reduce the number of bubbles in the reflecting layer 20 and improve the reflection efficiency of the reflecting layer 20 to ultrasonic waves. The defoaming agent can be modified dimethylsilane or polyoxypropylene ethylene oxide glycerol ether, or a mixed defoaming agent of the modified dimethylsilane and the polyoxypropylene ethylene oxide glycerol ether. The mass ratio of the defoaming agent in the reflecting layer 20 is 1.0-3.0%. In a preferred embodiment, the mass ratio of the defoaming agent in the reflective layer 20 is 1.5% to 2.5%. When the mass ratio of the defoaming agent is 1.5%, a small amount of bubbles can exist in the liquid ink material after stirring, and the reflecting layer 20 formed after the liquid ink material is cured also has a small amount of bubbles, so that the ultrasonic fingerprint module 100 meets the requirement of fingerprint identification. When the mass percentage of defoaming agent is 2.5% bubble in the liquid printing ink material after can effectively eliminating the stirring to can make the reflecting layer 20 that forms after the liquid printing ink material solidification also not contain the bubble, the ultrasonic fingerprint module 100 that is equipped with this reflecting layer 20 is excellent in performance, and fingerprint identification is efficient.

The leveling agent is contained in the liquid ink material, so that the surface roughness of the reflecting layer 20 can be effectively reduced, and the reflection efficiency of the reflecting layer 20 to ultrasonic waves is improved. The leveling agent can be fluorocarbon organic modified siloxane or polyether siloxane copolymer, or a mixed leveling agent of fluorocarbon organic modified siloxane and polyether siloxane copolymer. The mass percentage of the flatting agent in the reflecting layer 20 is 0.2-1.5%. In a preferred embodiment, the mass ratio of the leveling agent in the reflective layer 20 is 0.5% to 1.0%. When the mass percentage of the leveling agent is 0.5%, the surface of the reflecting layer 20 formed after the liquid ink material is cured is smooth, and the surface roughness of the reflecting layer 20 can be controlled to be 0.6 Rz/mum. When the mass percentage of the leveling agent is 1.0%, the surface roughness of the reflecting layer 20 formed after the liquid ink material is cured can be controlled to be 0.4 Rz/mum, so that the ultrasonic identification efficiency of the ultrasonic fingerprint module 100 is effectively improved.

103: the liquid ink material is laid on the bottom surface of the detection layer of the ultrasonic detection layer 10, a reflection layer 20 is formed after the liquid ink material is solidified, and the reflection layer 20 covers the ultrasonic receiving surface of the ultrasonic detection layer 10.

In this embodiment, the surface of the outermost conductive electrode 16, which is away from the piezoelectric layer 15, forms the detection layer bottom surface of the ultrasonic detection layer 10. The liquid ink material may be formed on the conductive electrode 16 by vacuum evaporation, screen printing, spraying, or sputtering.

In another embodiment, the length and width of the substrate layer 13 may be at least n times of the required length and width of the ultrasonic fingerprint module 100, so that after the pixel electrode layer 14, the piezoelectric layer 15, the conductive electrode 16 and the reflective layer 20 with large areas are sequentially formed on the substrate layer 13, a plurality of ultrasonic fingerprint modules 100 may be obtained in batch by cutting. The pixel electrode layer 15, the piezoelectric layer 15, the conductive electrode 16 and the reflective layer 20 can be processed and molded according to a plurality of preset ultrasonic fingerprint module 100 array arrangement areas, so that the manufacturing cost for obtaining a plurality of ultrasonic fingerprint modules 100 in batches is reduced.

Referring to fig. 5, the present application further provides a display screen assembly 200, where the display screen assembly 200 includes a display screen 210 and the ultrasonic fingerprint module 100. The display screen 210 has an outer surface 211 facing a user, the ultrasonic fingerprint module 100 is fixed in the screen of the display screen 210 or under the screen, and the reflecting layer 20 is far away from the outer surface 211 relative to the ultrasonic detection layer 10.

Referring to fig. 6, in one embodiment, the reflective layer 20 of the ultrasonic fingerprint module 100 is opaque to visible light. The ultrasonic fingerprint module 100 is fixed under the screen of the display screen 210, and the reflecting layer 20 blocks the display light of the display screen 210 from exiting from the surface far away from the outer surface 211.

Specifically, the display screen 210 is provided with an organic electroluminescent layer 212, and the ultrasonic detection layer 10 is laminated on one surface of the organic electroluminescent layer 212 far from the outer surface 211. The display screen 210 is provided with a glass cover plate 213. The outer surface 211 is disposed on the glass cover plate 213. The organic electroluminescent layer 212 is attached to the glass cover plate 213. The substrate layer 13 of the ultrasonic detection layer 10 is bonded to the organic electroluminescent layer 212. The substrate layer 13 may constitute a base layer of the organic electroluminescent layer 212. The substrate layer 13 may be bonded to the organic electroluminescent layer 212 through a glue layer. The display screen 210 is an OLED (Organic Light-Emitting Diode) display screen 210. By utilizing the light-tight property of the reflection layer 20 of the ultrasonic fingerprint module 100, the reflection layer 20 can form a back plate of the display screen 210, so that the display screen 210 can display images conveniently. The display screen 210 may be a flexible display screen. The ultrasonic fingerprint module 100 can be bent and deformed along with the display screen 210.

It is understood that by setting the distance from the side of the fingerprint detection layer 10 attached to the reflection layer 20 to the outer surface 211 and setting the ultrasonic detection layer 10 to emit ultrasonic waves at a frequency, the piezoelectric layer 15 of the ultrasonic detection layer 10 emits a first ultrasonic signal 01 toward the outer surface 211 and a second ultrasonic signal 02 toward the reflection layer 20. The second ultrasonic signal 02 is reflected by the interface where the reflective layer 20 is in contact with the air to form a third ultrasonic signal 03. The third ultrasonic signal 03 is also emitted towards said outer surface 211. The third ultrasonic signal 03 and the first ultrasonic signal 01 may form resonance and are emitted toward the outer surface 211 together to enhance fingerprint recognition efficiency.

Through testing, six display screen assemblies 200 are provided, the thicknesses of the reflecting layers 20 in the six display screen assemblies 200 are different from each other, and the SNR value of the ultrasonic fingerprint module 100 in the six display screen assemblies 200 and the acquired fingerprint image resolution (LPMM) value are compared. For example, the thicknesses of the reflective layers 20 in the six display screen assemblies 200 are respectively 5 μm, 10 μm, 15 μm, 20 μm, 25 μm and 30 μm, the SNR values of the ultrasonic fingerprint modules 100 in the six display screen assemblies 200 are respectively 4.571, 4.9, 5.308, 5.859, 6.105 and 5.72 after testing, and the fingerprint image resolution (LPMM) values obtained by the ultrasonic fingerprint modules 100 in the six display screen assemblies 200 are respectively 3.23, 3.32, 3.421, 3.594, 3.593 and 3.6. It can be seen that, when the thickness of the reflective layer 20 is 25 μm, the performance of the ultrasonic fingerprint module 100 of the display screen assembly 200 is excellent. That is, as a preferred embodiment, the thickness of the reflective layer 20 of the ultrasonic fingerprint module 100 may be set to be 20 μm to 30 μm.

Referring to fig. 7 and fig. 8, in another embodiment, substantially the same as the embodiment shown in fig. 6, except that the display screen 210 is provided with a liquid crystal panel 214 and a backlight module 215, the backlight module 215 includes a backlight light guide plate 216 attached to the liquid crystal panel 214 and a backlight source 217 fixed to a side of the backlight light guide plate 216, and the ultrasonic detection layer 10 is attached to a surface of the backlight light guide plate 216 away from the liquid crystal panel 214. The liquid crystal panel 214 is attached to the glass cover plate 213. The substrate layer 13 is attached to the backlight light guide plate 216. The substrate layer 13 may constitute a base layer of the backlight light guide plate 216. Due to the non-light-transmission property of the reflective layer 20, the reflective layer 20 can form a back plate of the backlight module 215, so that the liquid crystal panel 214 obtains the light of the backlight module 215, and further, the image display is realized. In order to increase the structural stability of the backlight module 215, the backlight module 215 further includes a package substrate 218, the package substrate 218 encapsulates the backlight source 217 and the backlight light guide plate 216, and the ultrasonic fingerprint module 100 is fixed between the backlight light guide plate 216 and the package substrate 218. The package substrate 218 protects the ultrasonic fingerprint module 100, and the package substrate 218 further packages the backlight source 217 to prevent the backlight source 217 from leaking light. The package bottom plate 218 may be a bendable sheet metal piece. There is an assembly gap between the package substrate 218 and the ultrasonic fingerprint module 100 to increase the ultrasonic blocking rate of the reflective layer 20, and ensure the effectiveness of the ultrasonic fingerprint module 100 in recognizing fingerprints.

Referring to fig. 9, in another embodiment, substantially the same as the embodiment shown in fig. 6, the ultrasonic fingerprint module 100 can be embedded in the display screen 210, and the ultrasonic fingerprint module 100 is located in a non-display area of the display screen 210. Specifically, the glass cover plate 213 has a non-light-transmitting area 2131. The opaque region 2131 of the glass cover plate 213 is formed of a reflective layer attached to glass. The opaque area 2131 of the glass cover plate 213 covers the ultrasonic fingerprint module 100, so as to ensure the appearance performance of the display screen 210 assembly 200. Utilize ultrasonic fingerprint module 100 set up in the non-display area of display screen 210 subassembly 200 avoids ultrasonic fingerprint module 100's reflection stratum 20 blocks display light to guarantee the display effect of the display area of display screen 210 subassembly 200. There is the clearance between the reflection stratum 20 of ultrasonic fingerprint module 100 and other layer structures of display screen 210 subassembly 200 to guarantee reflection stratum 20 blocks efficiency to the ultrasonic wave, guarantees the fingerprint identification validity of ultrasonic fingerprint module 100.

Referring to fig. 10, in another embodiment, substantially the same as the embodiment shown in fig. 7, except that the display panel 210 is provided with a substrate 2101 attached to the organic electroluminescent layer 212, the ultrasonic detection layer 10 includes a plurality of pixel electrodes 14, a piezoelectric layer 15 and a conductive electrode 16, the plurality of pixel electrodes 14 are arranged in an array on a surface of the substrate 2101 away from the glass cover 213, the piezoelectric layer 15 covers the plurality of pixel electrodes 14, the conductive electrode 16 is laminated on a surface of the piezoelectric layer 15 away from the plurality of pixel electrodes 14, and the reflective layer 20 is formed by printing on a surface of the conductive electrode 16 away from the piezoelectric layer 15. That is, the ultrasonic fingerprint module 100 is attached to the substrate 2101 of the display screen 210. Of course, in other embodiments, the display screen 210 is provided with the substrate 2101 of the liquid crystal panel 214, and the plurality of pixel electrodes 14 of the ultrasonic fingerprint module 100 may be formed on the substrate 2101 of the liquid crystal panel 214.

Referring to fig. 11, the present application further provides an electronic device 300, where the electronic device 300 includes the display screen assembly 200, and the electronic device 300 further includes a rear cover 310 and a main board 320. The display screen 210 is covered with the rear cover 310. The main board 320 is fixed between the rear cover 310 and the display screen 210, and the main board 320 is electrically connected to the display screen 210 and the ultrasonic fingerprint module 100. The main board 320 can receive the electrical signal of the ultrasonic fingerprint module 100 to identify a fingerprint image of a user. It can be understood that ultrasonic fingerprint module 100 can receive the fingerprint detected signal through user's fingerprint detection, the fingerprint detected signal through user's fingerprint detection can be by the initial detected signal conduction of ultrasonic fingerprint module 100 transmission is to user's fingerprint, also can be by the initial detected signal conduction of outside ultrasonic signal source transmission to user's fingerprint. The electronic device 300 may be a mobile phone, a tablet computer, a notebook computer, a media player, or a financial terminal device such as an Automated Teller Machine (ATM). Electronic equipment 300 is through inciting somebody to action ultrasonic wave fingerprint module 100 set up in the display screen 210, make electronic equipment 300 can satisfy diversified fingerprint identification requirement, improves fingerprint identification efficiency.

It is to be understood that any specific numerical value having a protective meaning in this embodiment is not limited to the specific numerical values provided above, and other numerical values similar to the specific numerical values provided in this embodiment are also within the protective scope of the embodiments of the present application.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. an ultrasonic fingerprint module is characterized in that, the ultrasonic fingerprint module comprises an ultrasonic detection layer and a reflection layer, the ultrasonic detection layer has an ultrasonic receiving surface, and the reflection layer is arranged on the ultrasonic detection layer away from all One side of the ultrasonic receiving surface, the reflective layer is used to reflect the ultrasonic waves emitted from the ultrasonic detection layer, the reflective layer contains a leveling agent, and the leveling agent is used to improve the production process of the reflective layer. and improve the surface leveling of the final reflective layer.

2 . The ultrasonic fingerprint module according to claim 1 , wherein the mass ratio of the leveling agent in the reflective layer is 0.2% to 1.5%. 3 .

3 . The ultrasonic fingerprint module according to claim 1 , wherein the leveling agent comprises a fluorocarbon type leveling agent. 4 .

4. The ultrasonic fingerprint module according to claim 3, wherein the fluorocarbon leveling agent is a fluorocarbon organic modified siloxane.

5 . The ultrasonic fingerprint module according to claim 4 , wherein the leveling agent further comprises a polyether siloxane copolymer. 6 .

6 . The ultrasonic fingerprint module according to claim 5 , wherein the mass ratio of the fluorocarbon organo-modified siloxane in the reflective layer is 0.1% to 0.75%, and the polyether silicone The mass proportion of the alkane copolymer in the reflective layer is 0.1%-0.75%.

7 . The ultrasonic fingerprint module according to claim 6 , wherein the mass ratio of the fluorocarbon organo-modified siloxane in the reflection layer is 0.2% to 0.6%. 8 .

8 . The ultrasonic fingerprint module according to claim 7 , wherein the mass ratio of the fluorocarbon organo-modified siloxane in the reflective layer is 0.5%. 9 .

9 . The ultrasonic fingerprint module according to claim 6 , wherein the mass ratio of the polyether siloxane copolymer in the reflective layer is 0.2% to 0.6%. 10 .

10 . The ultrasonic fingerprint module according to claim 8 , wherein the mass ratio of the polyether siloxane copolymer in the reflection layer is 0.5%. 11 .

11 . The ultrasonic fingerprint module according to claim 1 , wherein the reflective layer contains carbon powder particles and a resin material, and the carbon powder particles are mixed into the gaps between molecules in the resin material. 12 .

12 . The ultrasonic fingerprint module according to claim 1 , wherein the ultrasonic detection layer comprises a substrate layer, a pixel electrode layer, a piezoelectric layer and a conductive electrode layered in sequence, and the reflective layer is arranged on the The conductive electrode is away from the side of the piezoelectric layer.

13 . The ultrasonic fingerprint module according to claim 12 , wherein the ultrasonic detection layer comprises two or more layers of the conductive electrodes. 14 .

14 . The ultrasonic fingerprint module according to claim 1 , wherein the reflective layer has a thickness of 5 μm to 30 μm. 15 .

15. The ultrasonic fingerprint module of claim 14, wherein the reflective layer has a thickness of 20 to 30 microns.

16. The ultrasonic fingerprint module of claim 15, wherein the reflective layer has a thickness of 25 microns.

17. A method of making an ultrasonic fingerprint module, wherein the method of making the ultrasonic fingerprint module comprises the steps:

An ultrasonic detection layer is provided, the ultrasonic detection layer has an ultrasonic receiving surface and a detection layer bottom surface disposed opposite to the ultrasonic receiving surface;

Provide liquid molding material containing leveling agent;

The liquid molding material is laid on the bottom surface of the detection layer, and a reflection layer is formed after the liquid molding material is cured, and the reflection layer covers the ultrasonic wave receiving surface of the ultrasonic detection layer.

18 . The method for making an ultrasonic fingerprint module according to claim 17 , wherein the liquid ink material further contains carbon powder particles, a resin material and a defoamer, and the resin material, carbon powder particles, leveling The liquid molding material is formed after mixing and stirring the antifoaming agent and the antifoaming agent.

19 . An electronic device, characterized in that, the electronic device comprises the ultrasonic fingerprint module according to any one of claims 1 to 16 .