Hybrid curing adhesive layer, screen protection film and electronic device

Abstract

Disclosed in the present application are a hybrid curing adhesive layer, a screen protection film and an electronic device. The hybrid curing adhesive layer is used for attaching a glass layer to an outer screen of a screen, wherein the screen is a screen of an electronic device having an under-display ultrasonic fingerprint recognition function; the hybrid curing adhesive layer comprises N first adhesive layers, a substrate layer and M second adhesive layers, which are sequentially arranged, wherein the first one of the first adhesive layers is used for attaching to the glass layer, and the last one of the second adhesive layers is used for attaching to the outer screen of the screen; and on the basis of the relationship between the acoustic impedance of an i-th structural layer and the acoustic impedances of two adjacent structural layers, the thickness of the i-th structural layer is determined to be formula (I) or (II). By rationally selecting the layer stack materials of the screen protection film and designing the layer stack thickness, the screen protection film has the advantages of high ultrasonic transmittance at a specific frequency and low energy attenuation.

Description

Hybrid hardening adhesive layer, screen protection film and electronic device

[0001] This application claims priority to the Chinese patent application No. 202421538527.5, filed on June 28, 2024, entitled "A screen protection film, a two-liquid hybrid hardening adhesive layer and an electronic device", the entire content of which is incorporated herein by reference. This application claims priority to the Chinese patent application No. 202421520306.5, filed on June 28, 2024, entitled "A screen protection film, a two-liquid hybrid hardening adhesive layer and an electronic device", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of fingerprint identification technology, and in particular to a hybrid hardening adhesive layer, a screen protection film and an electronic device. BACKGROUND

[0003] With the popularity of ultrasonic under-screen fingerprint technology in electronic devices such as smart phones, how to obtain more accurate fingerprint identification effect has become the focus of research on ultrasonic under-screen fingerprint technology. However, in order to protect the outer screen of the screen of the electronic device, the user usually pastes a screen protection film on the surface of the outer screen of the screen of the electronic device, which will seriously affect the identification effect of the ultrasonic under-screen fingerprint.

[0004] Therefore, how to improve the influence of the screen protection film on the ultrasonic under-screen fingerprint identification and better achieve fingerprint identification has become a technical problem to be solved. SUMMARY

[0005] The embodiments of the present application provide a hybrid hardening adhesive layer, a screen protection film and an electronic device to improve the influence of the screen protection film on the ultrasonic under-screen fingerprint identification and better achieve fingerprint identification.

[0006] A hybrid hardening adhesive layer for attaching a glass layer to an outer screen of a screen, the screen being a screen of an electronic device having an under-screen ultrasonic fingerprint identification function; the hybrid hardening adhesive layer comprising N first adhesive layers, a substrate layer and M second adhesive layers arranged in sequence, the first first adhesive layer being used for attaching to the glass layer, the last second adhesive layer being used for attaching to the outer screen of the screen, N being a positive integer, M being a positive integer;

[0007] The thickness of at least one structural layer of the hybrid hardening adhesive layer satisfies the following thickness condition: if the acoustic impedance of the i-1th structural layer is the same as the acoustic impedance of the i+1th structural layer, then the thickness of the i th structural layer is If the acoustic impedance of the (i-1)th structural layer is different from that of the (i+1)th structural layer, and the acoustic impedance of the ith structural layer falls between the acoustic impedances of the (i-1)th and (i+1)th structural layers, then the thickness of the ith structural layer is: If the acoustic impedance of the (i-1)th structural layer is different from that of the (i+1)th structural layer, and the acoustic impedance of the ith structural layer is not between that of the (i-1)th and (i+1)th structural layers, then the thickness of the ith structural layer is:

[0008] Wherein, the i-th structural layer is any one of the N first adhesive layers, the substrate layer, and the M second adhesive layers; λi is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the i-th structural layer, k is a positive integer, 2≤i≤(N+M+1).

[0009] A screen protector is used to attach to the outer screen of an electronic device that has an under-display ultrasonic fingerprint recognition function. The screen protector includes a glass layer and the aforementioned mixed hardened adhesive layer.

[0010] The first adhesive layer of the mixed-curing adhesive layer is attached to the glass layer, and the last adhesive layer of the mixed-curing adhesive layer is attached to the outer screen of the screen.

[0011] The thickness of the glass layer is Where λglass is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the glass layer, and S is a positive integer.

[0012] An electronic device includes the aforementioned screen protector and the screen, wherein the screen protector is attached to the outer screen of the screen.

[0013] In the embodiment of this application, the screen protector includes a glass layer and a hybrid curing adhesive layer. The hybrid curing adhesive layer includes N first adhesive layers, a substrate layer, and M second adhesive layers sequentially disposed. The first first adhesive layer is used to adhere to the glass layer, and the last second adhesive layer is used to adhere to the outer screen. The thickness of the i-th structural layer is determined based on the relationship between the acoustic impedance of the i-th structural layer and the acoustic impedance of two adjacent structural layers. or By rationally selecting the lamination materials and designing the lamination thickness of the screen protector, the screen protector can have the advantages of high transmittance of ultrasonic waves of a specific frequency and low energy attenuation.

[0014] A screen protector is applied to a screen with under-display ultrasonic fingerprint recognition function. The screen protector includes a glass layer and a mixed curing adhesive layer. The glass layer is attached to the surface of the screen through the mixed curing adhesive layer. The mixed curing adhesive layer includes a semi-cured photosensitive adhesive layer, a substrate layer, and a silicone layer arranged sequentially.

[0015] Preferably, the propagation time of the ultrasonic wave in the mixed hardening adhesive layer is equal to or; the sum of the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer and the substrate layer is equal to or; the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer is equal to wherein N is a positive integer, and T0 is the period of the ultrasonic wave.

[0016] Preferably, if the sum of the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer and the substrate layer is equal to then the thickness of the silica gel layer is equal to λ1 / 2*M or less than λ1 / 8; or, if the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer is equal to then the thickness of the silica gel layer is equal to λ1 / 2*M or less than λ1 / 8 and the thickness of the substrate layer is equal to λ4 / 2*M or less than λ4 / 8; wherein M is a positive integer, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, and λ4 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the substrate layer.

[0017] Preferably, if the frequency of the ultrasonic wave is 11 MHz; the substrate layer is a PET film; the thickness of the semi-cured photosensitive adhesive layer is 260 um; the thickness of the substrate layer is 50 um; and the thickness of the silica gel layer is 50 um; or, the thickness of the semi-cured photosensitive adhesive layer is 130 um; the thickness of the substrate layer is 50 um; and the thickness of the silica gel layer is 50 um or 20 um; or, the thickness of the semi-cured photosensitive adhesive layer is 60 um; the thickness of the substrate layer is 50 um; and the thickness of the silica gel layer is 20 um.

[0018] Preferably, the thickness of the silica gel layer is less than the thickness of the semi-cured photosensitive adhesive layer; the thickness of the silica gel layer is less than the thickness of the substrate layer.

[0019] Preferably, the thickness of the semi-cured photosensitive adhesive layer is equal to λ2 / 2*O or less than λ2 / 8, the thickness of the substrate layer is equal to λ4 / 2*P or less than λ4 / 8, and the thickness of the silica gel layer is equal to λ1 / 2*Q or less than λ1 / 8, wherein O, P, and Q are positive integers, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the cured semi-cured photosensitive adhesive layer, and λ4 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the substrate layer.

[0020] Preferably, if the frequency of the ultrasonic wave is 11MHz; the substrate layer is PET film; the thickness of the semi-cured photosensitive adhesive layer is 130um; the thickness of the substrate layer is 50um; and the thickness of the silica gel layer is 50um.

[0021] Preferably, the mixed hardening adhesive layer further comprises an optical adhesive layer arranged between the semi-cured photosensitive adhesive layer and the substrate layer.

[0022] Preferably, the thickness of the optical adhesive layer is equal to λ5 / 2*R, and the thickness of the semi-cured photosensitive adhesive layer is λ2 / 4 or 3λ2 / 4; or, the sum of the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer and the optical adhesive layer is equal to wherein R, S are positive integers, T0 is the period of the ultrasonic wave, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the semi-cured photosensitive adhesive layer after curing, and λ5 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer.

[0023] Preferably, the propagation time of the ultrasonic wave in the mixed hardening adhesive layer is equal to or; the sum of the propagation time of the ultrasonic wave in the optical adhesive layer and the substrate layer is equal to wherein T, N are positive integers, and T0 is the period of the ultrasonic wave.

[0024] Preferably, the sum of the propagation time of the ultrasonic wave in the silica gel layer and the substrate layer is equal to wherein W is a positive integer, and T0 is the period of the ultrasonic wave.

[0025] Preferably, if the frequency of the ultrasonic wave is 11MHz; the substrate layer is a PET film; the thickness of the semi-cured photosensitive adhesive layer is 60um; the thickness of the optical adhesive layer is 120um; the thickness of the substrate layer is 50um; and the thickness of the silica gel layer is 50um; or the thickness of the semi-cured photosensitive adhesive layer is 100um; the thickness of the optical adhesive layer is 80um; the thickness of the substrate layer is 50um; and the thickness of the silica gel layer is 50um; or the thickness of the semi-cured photosensitive adhesive layer is 60um; the thickness of the optical adhesive layer is 180um; the thickness of the substrate layer is 75um; and the thickness of the silica gel layer is 50um; or the thickness of the semi-cured photosensitive adhesive layer is 180um; the thickness of the optical adhesive layer is 120um; the thickness of the substrate layer is 50um; and the thickness of the silica gel layer is 50um; or the thickness of the semi-cured photosensitive adhesive layer is 60um; the thickness of the optical adhesive layer is 120um; the thickness of the substrate layer is 20um; and the thickness of the silica gel layer is 50um; or the thickness of the semi-cured photosensitive adhesive layer is 200um; the thickness of the optical adhesive layer is 80um or 160um or 240um; the thickness of the substrate layer is 20um; and the thickness of the silica gel layer is 50um; or the thickness of the semi-cured photosensitive adhesive layer is 60um; the thickness of the optical adhesive layer is 160um or 240um; the thickness of the substrate layer is 20um; and the thickness of the silica gel layer is 50um.

[0026] Preferably, the floating range of the propagation time and the thickness is ±20%.

[0027] Preferably, the thickness of the glass layer has a floating range of ±10%, and the thickness of the semi-cured photosensitive adhesive layer, the substrate layer and the silica gel layer has a floating range of ±20%.

[0028] Preferably, the floating range of the propagation time and the thickness is ±10%.

[0029] Preferably, the two sides of the mixed hardening adhesive layer are respectively provided with an upper release film and a lower release film.

[0030] A mixed hardening adhesive layer applied to adhere a glass layer to the surface of a screen with an under-screen ultrasonic fingerprint recognition function, the mixed hardening adhesive layer comprising an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence, and the two sides of the mixed hardening adhesive layer are respectively provided with an upper release film and a lower release film.

[0031] An electronic device comprising a screen with an under-screen ultrasonic fingerprint recognition function and any of the above screen protection films or mixed hardening adhesive layers and a glass layer attached by the mixed hardening adhesive layer.

[0032] In the scheme of the embodiment of the application, the screen protection film comprises a glass layer and a mixed hardening adhesive layer, the glass layer is attached to the surface of the screen through the mixed hardening adhesive layer, and the mixed hardening adhesive layer comprises a semi-cured photosensitive adhesive layer, a substrate layer and a silica gel layer arranged in sequence. The semi-cured photosensitive adhesive layer avoids the attenuation of ultrasonic waves caused by a thick optical adhesive layer, thereby improving the influence of the tempered protection film on the ultrasonic under-screen fingerprint identification and better realizing the fingerprint identification.

[0033] A screen protection film applied to a screen with an under-screen ultrasonic fingerprint identification function, the screen protection film comprising: a glass layer and a mixed hardening adhesive layer, the mixed hardening adhesive layer being used to attach the glass layer to the surface of the screen, the mixed hardening adhesive layer comprising an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence, the propagation time of the ultrasonic wave in the mixed hardening adhesive layer being equal to or; the sum of the propagation times of the ultrasonic wave in the optical adhesive layer and the substrate layer being equal to or; the sum of the propagation times of the ultrasonic wave in the substrate layer and the silica gel layer being equal to wherein N is a positive integer, and T0 is the period of the ultrasonic wave.

[0034] Preferably, if the sum of the propagation times of the ultrasonic wave in the optical adhesive layer and the substrate layer is equal to then the thickness of the silica gel layer is equal to λ1 / 2*M or less than λ1 / 8; or, if the sum of the propagation times of the ultrasonic wave in the substrate layer and the silica gel layer is equal to then the thickness of the optical adhesive layer is equal to λ2 / 2*M or less than λ2 / 8; wherein M is a positive integer, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, and λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer.

[0035] Preferably, if the frequency of the ultrasonic wave is 11 MHz; the substrate layer is a PET film; the thickness of the optical adhesive layer is 30 um; the thickness of the substrate layer is 25 um; and the thickness of the silica gel layer is 20 um; or the thickness of the optical adhesive layer is 55 um; the thickness of the substrate layer is 30 um; and the thickness of the silica gel layer is 55 um; or the thickness of the optical adhesive layer is 75 um; the thickness of the substrate layer is 20 um; and the thickness of the silica gel layer is 45 um.

[0036] Preferably, the thickness of the silica gel layer is less than the thickness of the optical adhesive layer; and the thickness of the silica gel layer is less than the thickness of the substrate layer.

[0037] A screen protection film applied to a screen with an under-screen ultrasonic fingerprint identification function, wherein the screen protection film comprises a glass layer and a mixed hardening adhesive layer, the glass layer is used to be attached to the surface of the screen through the mixed hardening adhesive layer, the mixed hardening adhesive layer comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence, the thickness of the optical adhesive layer is equal to λ2 / 2*O or less than λ2 / 8, the thickness of the substrate layer is equal to λ4 / 2*P or less than λ4 / 8, and the thickness of the silica gel layer is equal to λ1 / 2*Q or less than λ1 / 8, wherein O, P and Q are positive integers, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer, and λ4 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the substrate layer.

[0038] Preferably, if the frequency of the ultrasonic wave is 11 MHz, the thickness of the optical adhesive layer is 75 um, the thickness of the substrate layer is 20 um, and the thickness of the silica gel layer is 55 um.

[0039] Preferably, the thickness of the glass layer is λ3 / 2, and λ3 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the glass.

[0040] Preferably, the thickness of the glass layer is 250 um.

[0041] Preferably, the floating range of the propagation time and the thickness is plus or minus 20%.

[0042] Preferably, the thickness of the glass layer has a floating range of plus or minus 10%, and the thickness of the optical adhesive layer, the substrate layer and the silica gel layer has a floating range of plus or minus 20%.

[0043] Preferably, the floating range of the propagation time and the thickness is plus or minus 10%.

[0044] Preferably, one side of the mixed hardening adhesive layer is used to set a release film, or both sides of the mixed hardening adhesive layer are used to set release films.

[0045] A mixed hardening adhesive layer applied to attach a glass layer to the surface of a screen with an under-screen ultrasonic fingerprint identification function, the mixed hardening adhesive layer comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence, the propagation time of the ultrasonic wave in the mixed hardening adhesive layer is equal to or the sum of the propagation time of the ultrasonic wave in the optical adhesive layer and the substrate layer is equal to or the sum of the propagation time of the ultrasonic wave in the substrate layer and the silica gel layer is equal to wherein N is a positive integer, T0 is the period of the ultrasonic wave, and the mixed hardening adhesive layer is provided with an upper release film and a lower release film on both sides, respectively.

[0046] A mixed hardening adhesive layer is applied to adhere a glass layer to the surface of a screen with an under-screen ultrasonic fingerprint recognition function, characterized in that the mixed hardening adhesive layer comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence, the thickness of the optical adhesive layer is equal to λ2 / 2*O or less than λ2 / 8, the thickness of the substrate layer is equal to λ4 / 2*P or less than λ4 / 8, and the thickness of the silica gel layer is equal to λ1 / 2*Q or less than λ1 / 8, wherein O, P and Q are positive integers, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer, and λ4 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the substrate layer; the mixed hardening adhesive layer is provided with an upper release film and a lower release film on both sides thereof.

[0047] An electronic device comprises a screen with an under-screen ultrasonic fingerprint recognition function and any of the above screen protection films or the mixed hardening adhesive layer and a glass layer attached by the mixed hardening adhesive layer.

[0048] In the scheme of the embodiments of the present application, the screen protection film comprises a glass layer and a mixed hardening adhesive layer, the glass layer is attached to the surface of the screen through the mixed hardening adhesive layer, and the mixed hardening adhesive layer comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence. The thickness of the optical adhesive layer, the substrate layer and the silica gel layer is set to improve the influence of the tempered protection film on the ultrasonic under-screen fingerprint recognition and better realize the fingerprint recognition. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0050] Fig. 1 is an application schematic diagram of an outer screen and a screen protection film of a screen for ultrasonic under-screen fingerprint recognition in the embodiments of the present application;

[0051] Fig. 2 is a structural schematic diagram of a screen protection film shown in Fig. 1;

[0052] Fig. 3 is another application schematic diagram of an outer screen and a screen protection film of a screen for ultrasonic under-screen fingerprint recognition in the embodiments of the present application;

[0053] Fig. 4 is a structural schematic diagram of a screen protection film shown in Fig. 2;

[0054] Fig. 5 is another structural schematic diagram of a screen protection film shown in Fig. 2.

[0055] Fig. 6 is a structural schematic diagram of a display screen of the ultrasonic under-screen fingerprint recognition according to an embodiment of the present application;

[0056] Fig. 7 is a structural schematic diagram of a display screen and a screen protection film of the ultrasonic under-screen fingerprint recognition;

[0057] Fig. 8 is a curve diagram of the ultrasonic transmittance of a glass layer when the ultrasonic frequency is 11 MHz;

[0058] Fig. 9 is a structural schematic diagram of a screen protection film according to an embodiment of the present application;

[0059] Fig. 10 is another structural schematic diagram of a screen protection film according to an embodiment of the present application;

[0060] Fig. 11 is still another structural schematic diagram of a screen protection film according to an embodiment of the present application. DETAILED DESCRIPTION

[0061] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0062] The basic principle of the ultrasonic under-screen fingerprint recognition is that the ultrasonic fingerprint module is installed below the screen, the screen includes an outer screen of the screen and a plurality of stacked structures, such as a touch layer and a display layer, which are arranged below the outer screen of the screen, and the ultrasonic fingerprint module is specifically installed below the plurality of stacked structures; if the screen is not pasted with a screen protection film, the ultrasonic wave emitted thereby is reflected on the contact surface between the outer screen of the screen and the finger after transmitting through the outer screen of the screen. Since the reflection rates of the valleys and ridges of the fingerprint to the ultrasonic wave are different, the reflected echo is transmitted through the screen and received by the ultrasonic fingerprint module, and the fingerprint image can be obtained according to the echo difference. Referring to Fig. 6, the ultrasonic fingerprint module is installed below the OLED screen, the ultrasonic wave emitted thereby is transmitted through the OLED screen and reaches the surface of the finger, and the fingerprint of the finger reflects the ultrasonic wave. Since the reflection rates of the valleys and ridges of the fingerprint to the ultrasonic wave are different, the reflected echo is transmitted through the OLED screen and received by the ultrasonic fingerprint module, and the fingerprint image can be obtained according to the echo difference.

[0063] An embodiment of the present application provides a mixed hardening adhesive layer for attaching a glass layer to an outer screen of a screen, the screen being a screen of an electronic device with an under-screen ultrasonic fingerprint recognition function. The mixed hardening adhesive layer comprises N first adhesive layers, a substrate layer and M second adhesive layers arranged in sequence, the first first adhesive layer is used for attaching to the glass layer, and the last second adhesive layer is used for attaching to the outer screen of the screen. In the embodiment, the material of the outer screen of the screen is glass. In the embodiment, M and N are positive integers. In other embodiments, in order to reduce the thickness of the tempered film to improve the ultrasonic transmission rate, the number of layers of the first adhesive layer and the second adhesive layer can be 1 or 2, that is, in the embodiment, N is 1 or 2, and M is 1 or 2.

[0064] The i-1 structure layer is any one of the glass layer, the N first adhesive layers, the substrate layer and the M second adhesive layers, for example, when the i structure layer is the first first adhesive layer, the i-1 structure layer is the glass layer; when the i structure layer is the last second adhesive layer, the i+1 structure layer is the outer screen of the screen.

[0065] The thickness of at least one structure layer of the mixed hardening adhesive layer satisfies the following thickness condition: if the acoustic impedance of the i-1 structure layer is the same as the acoustic impedance of the i+1 structure layer, the thickness of the i structure layer is if the acoustic impedance of the i-1 structure layer is different from the acoustic impedance of the i+1 structure layer, and the acoustic impedance of the i structure layer is between the acoustic impedance of the i-1 structure layer and the acoustic impedance of the i+1 structure layer, the thickness of the i structure layer is if the acoustic impedance of the i-1 structure layer is different from the acoustic impedance of the i+1 structure layer, and the acoustic impedance of the i structure layer is not between the acoustic impedance of the i-1 structure layer and the acoustic impedance of the i+1 structure layer, the thickness of the i structure layer is wherein the i structure layer is any one of the N first adhesive layers, the substrate layer and the M second adhesive layers; λ i is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the i structure layer, k is a positive integer, and 2≤i≤(N+M+1).

[0066] The mixed hardening adhesive layer (AB adhesive) is used for attaching between the glass layer and the outer screen of the screen, and includes N first adhesive layers, a substrate layer and M second adhesive layers arranged in sequence from top to bottom, the first first adhesive layer is used for attaching to the glass layer, and the last second adhesive layer is used for attaching to the outer screen of the screen. When N and M are both 1, the mixed hardening adhesive layer has a 3-layer structure; when either of N and M is 1 and the other is 2, the mixed hardening adhesive layer has a 4-layer structure; when N and M are both 2, the mixed hardening adhesive layer has a 5-layer structure, which can be determined independently according to actual needs. The substrate layer can be made of various organic substances, and the substrate layer plays the role of a carrier plate. The first adhesive layer is an adhesive layer arranged between the glass layer and the substrate layer, used for bonding the glass layer and the substrate layer. The second adhesive layer is an adhesive layer arranged between the substrate layer and the outer screen of the screen, used for bonding the substrate layer and the outer screen of the screen.

[0067] According to the acoustic principle, when the ultrasonic wave propagates in three closely connected media, the acoustic impedance of the medium and the thickness of the intermediate layer medium will affect the penetration rate of the ultrasonic wave. The penetration rate here refers to the penetration rate of the ultrasonic wave from medium 1 through the intermediate layer medium 2 to medium 3. The screen protection film suitable for ultrasonic wave penetration provided in the embodiments of the present application can improve the effect of the screen protection film on the ultrasonic wave penetration rate by reasonably designing the laminated material and the laminated thickness of the screen protection film.

[0068] In an embodiment, the thickness of at least two structure layers of the mixed hardening adhesive layer satisfies the thickness condition, the first i-1 structure layer is the glass layer, and the last i+1 structure layer is the outer screen of the screen. FIG. 1 shows an application schematic diagram of the screen protection film (i.e. the tempered film) suitable for ultrasonic wave penetration attached to the outer screen of the screen of the electronic device in an embodiment of the present application. The first structure layer L1 of the screen protection film is the glass layer, and the thickness thereof is S1; the second structure layer L2 is the first adhesive layer, and the thickness thereof is S2; the third structure layer L3 is the substrate layer, and the thickness thereof is S3; the fourth structure layer L4 is the second adhesive layer, and the thickness thereof is S4; wherein the second structure layer L2, the third structure layer L3 and the fourth structure layer L4 form the mixed hardening adhesive layer (AB adhesive), and the total thickness thereof is S AB胶 The first adhesive layer is located between the glass layer and the substrate layer, and has the effect of bonding the glass layer and the substrate layer. The second adhesive layer is bonded to the other side of the substrate layer, and is not on the same side as the first adhesive layer. The mixed hardening adhesive layer is attached to the outer screen of the screen of the electronic device having the ultrasonic wave penetration requirement through the second adhesive layer of the fourth structure layer L4. In this example, the materials of the first adhesive layer and the second adhesive layer on both sides of the substrate layer are not limited, and transparent adhesive such as silicone, optical adhesive (OCA, Optically Clear Adhesive) or UV adhesive (or also known as photosensitive adhesive, ultraviolet light curing adhesive) which attenuates the ultrasonic signal less is preferred.

[0069] As shown in Figure 1, in a screen protector suitable for ultrasonic penetration, when the glass layer, the first adhesive layer, the substrate layer, and the second adhesive layer are determined, their corresponding acoustic impedances can be determined experimentally. Assuming the acoustic impedance of the glass layer is Z1, the acoustic impedance of the first adhesive layer is Z2, the acoustic impedance of the substrate layer is Z3, the acoustic impedance of the second adhesive layer is Z4, and the acoustic impedance of the object being tested or a finger is Z... s The acoustic impedance of the outer screen of the electronic device is also Z1. Looking upwards from the outer screen of the electronic device, the thickness of each structural layer of the screen protector is determined as follows:

[0070] The outer screen of the electronic device, the second adhesive layer of the fourth structural layer L4, and the substrate layer of the third structural layer L3 are tightly bonded together, with the second adhesive layer as the intermediate dielectric layer. Based on the characteristics of ultrasonic wave transmission, if the acoustic impedance Z1 of the outer screen of the electronic device is the same as the acoustic impedance Z3 of the substrate layer, the thickness S4 of the second adhesive layer is λ. 第二胶层 The thickness S4 of the second adhesive layer is approximately a multiple of 1 / 2. If the acoustic impedance Z1 of the outer screen is different from the acoustic impedance Z3 of the substrate layer, and if the acoustic impedance Z4 of the second adhesive layer is between the acoustic impedance Z1 of the outer screen and the acoustic impedance Z3 of the substrate layer, then the thickness S4 of the second adhesive layer is taken as the wavelength λ of the ultrasonic wave propagating in the second adhesive layer. 第二胶层 The thickness of the second adhesive layer is approximately one-quarter of an odd multiple, i.e., S4 is approximately equal to 1 / 4 of the thickness of the second adhesive layer. If the acoustic impedance Z4 of the second adhesive layer is not between the acoustic impedance Z1 of the outer screen of the electronic device and the acoustic impedance Z3 of the substrate layer, then the thickness S4 of the second adhesive layer is λ. 第二胶层 The thickness S4 of the second adhesive layer is approximately a multiple of 1 / 2. By setting the thickness S4 of the second adhesive layer in the above manner, the ultrasonic waves have a high penetration rate when transmitted from the outer screen of the electronic device to the substrate layer of the third structural layer L3.

[0071] The second adhesive layer of the fourth structural layer L4, the substrate layer of the third structural layer L3, and the first adhesive layer of the second structural layer L2 are tightly bonded together, with the substrate layer as the intermediate medium. Based on the characteristics of ultrasonic wave transmission, if the acoustic impedance Z3 of the substrate layer is between the acoustic impedance Z4 of the second adhesive layer and the acoustic impedance Z2 of the first adhesive layer, then the thickness S3 of the substrate layer is equal to the wavelength λ of the ultrasonic wave propagating in the substrate layer. 基材层 Approximately one-quarter of an odd multiple, i.e., the thickness S3 of the substrate layer is... If the acoustic impedance Z3 of the substrate layer is not between the acoustic impedance Z4 of the second adhesive layer and the acoustic impedance Z2 of the first adhesive layer, then the thickness S3 of the substrate layer is taken as λ. 基材层 The thickness S3 of the substrate layer is approximately a multiple of 1 / 2. The thickness S3 of the substrate layer is set according to the above method, and the ultrasonic wave has a high penetration rate from the second adhesive layer of the fourth structural layer L4 to the first adhesive layer of the second structural layer L2.

[0072] The substrate layer of the third structural layer L3, the first adhesive layer of the second structural layer L2, and the glass layer of the first structural layer L1 are tightly bonded together, with the first adhesive layer as the intermediate medium. Based on the characteristics of ultrasonic wave transmission, when the acoustic impedance Z3 of the substrate layer and the acoustic impedance Z1 of the glass layer are the same, the thickness S2 of the first adhesive layer is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer. 第一胶层 The thickness S2 of the first adhesive layer is approximately a multiple of 1 / 2. When the acoustic impedance Z3 of the substrate layer and the acoustic impedance Z1 of the glass layer are different, if the acoustic impedance Z2 of the first adhesive layer is between the acoustic impedance Z3 of the substrate layer and the acoustic impedance Z1 of the glass layer, then the thickness S2 of the first adhesive layer is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer. 第一胶层 The thickness S2 of the first adhesive layer is approximately one-quarter of an odd multiple, which is close to the value of the first adhesive layer. If the acoustic impedance Z2 of the first adhesive layer is not between the acoustic impedance Z3 of the substrate layer and the acoustic impedance Z1 of the glass layer, then the thickness S2 of the first adhesive layer is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer. 第一胶层 The thickness S2 of the first adhesive layer is approximately a multiple of 1 / 2. The thickness S2 of the first adhesive layer is set according to the above method, and the ultrasonic wave has a high penetration rate when it is transmitted from the substrate layer of the third structural layer L3 to the glass layer of the first structural layer L1.

[0073] When a finger or other object is pressed against the ultrasonic testing area on the glass layer of the screen protector, the three media—the first adhesive layer of the second structural layer L2, the glass layer of the first structural layer L1, and the finger—are tightly bonded together, with the glass layer serving as the intermediate layer. The acoustic impedance Z of the finger is known. s If the acoustic impedance Z2 of the first adhesive layer is less than the acoustic impedance Z1 of the glass layer, then the acoustic impedance Z1 of the glass layer is not related to the acoustic impedance Z2 of the first adhesive layer and the acoustic impedance Z of the finger. s Between these points, the thickness S1 of the glass layer is taken as λ. 玻璃 The thickness S1 of the glass layer is approximately a multiple of 1 / 2. Preferred If the acoustic impedance Z2 of the first adhesive layer is greater than the acoustic impedance Z1 of the glass layer, then the acoustic impedance Z1 of the glass layer is greater than the acoustic impedance Z2 of the first adhesive layer and the acoustic impedance Z of the finger. s Between these values, the thickness S1 of the glass layer is taken as λ. 玻璃 Nearly a quarter of an odd multiple, that is, the thickness of the glass layer is Wherein, λ glass is the wavelength of ultrasonic wave propagating in the glass layer, and k is a positive integer. By setting the thickness S1 of the glass layer in the above manner, the penetration rate of the ultrasonic wave from the first adhesive layer of the second structure layer L2 to the finger medium via the glass layer of the first structure layer L1 is high.

[0074] Fig. 3 shows a schematic diagram of an application of a screen protection film (i.e. tempered film) suitable for ultrasonic wave penetration to the outer screen of the screen of an electronic device according to an embodiment of the present application. The first structure layer L1 of the screen protection film is a glass layer with a thickness S1; the second structure layer L2 is a first adhesive layer 1 with a thickness S2; the third structure layer L3 is a first adhesive layer 2 with a thickness S3; the fourth structure layer L4 is a substrate layer with a thickness S4; and the fifth structure layer L5 is a second adhesive layer with a thickness S5. The second structure layer L2, the third structure layer L3, the fourth structure layer L4 and the fifth structure layer L5 form a mixed hardening adhesive layer (AB adhesive) with a total thickness S AB胶 . The two first adhesive layers are located between the glass layer and the substrate layer, and serve to bond the glass layer and the substrate layer. The second adhesive layer is bonded to the other side of the substrate layer, and is not on the same side as the first adhesive layer. The mixed hardening adhesive layer is attached to the outer screen surface of the screen of the electronic device having ultrasonic wave penetration requirements via the second adhesive layer of the fifth structure layer L5. In this example, the materials of the first adhesive layers and the second adhesive layer on both sides of the substrate layer are not limited, and transparent adhesive such as silicone, OCA adhesive or UV adhesive which has a small attenuation to ultrasonic signals is preferred.

[0075] As shown in Fig. 3, in the screen protection film suitable for ultrasonic wave penetration, the corresponding acoustic impedance of the glass layer, the first adhesive layer 1, the first adhesive layer 2, the substrate layer and the second adhesive layer can be determined by experimental tests. Assuming that the acoustic impedance of the glass layer is Z1, the acoustic impedance of the first adhesive layer 1 is Z2, the acoustic impedance of the first adhesive layer 2 is Z3, the acoustic impedance of the substrate layer is Z4, the acoustic impedance of the second adhesive layer is Z5, and the acoustic impedance of the detected object or the finger is Z s , and the acoustic impedance of the outer screen of the screen of the electronic device is also Z1. From the outer screen of the screen of the electronic device, the thicknesses of the structure layers of the screen protection film are determined as follows:

[0076] The outer screen of the screen of the electronic device, the second adhesive layer of the fifth structure layer L5 and the substrate layer of the fourth structure layer L4 are closely attached, and the intermediate medium layer is the second adhesive layer. According to the ultrasonic wave transmission characteristics, when the acoustic impedance Z1 of the outer screen of the screen and the acoustic impedance Z4 of the substrate layer are the same, the thickness S5 of the second adhesive layer is around 1 / 2 integer multiple of λ 第二胶层 , i.e. the thickness S5 of the second adhesive layer is When the acoustic impedance Z1 of the outer screen and the acoustic impedance Z4 of the substrate layer are not the same, if the acoustic impedance Z5 of the second adhesive layer is between the acoustic impedance Z1 of the outer screen and the acoustic impedance Z4 of the substrate layer, the thickness S5 of the second adhesive layer is taken as the wavelength λ of the ultrasonic wave propagating in the second adhesive layer. 第二胶层 The thickness of the second adhesive layer is approximately one-quarter of an odd multiple, i.e., S5 is approximately equal to 1 / 4 of the thickness of the second adhesive layer. If the acoustic impedance Z5 of the second adhesive layer is not between the acoustic impedance Z1 of the outer screen of the electronic device and the acoustic impedance Z4 of the substrate layer, then the thickness S5 of the second adhesive layer is λ. 第二胶层 The thickness S5 of the second adhesive layer is approximately a multiple of 1 / 2. By setting the thickness S5 of the second adhesive layer in the above manner, the ultrasonic waves have a high penetration rate when transmitted from the outer screen of the electronic device to the substrate layer of the fourth structural layer L4.

[0077] The second adhesive layer of the fifth structural layer L5, the substrate layer of the fourth structural layer L4, and the first adhesive layer 2 of the third structural layer L3 are tightly bonded together, with the substrate layer serving as the intermediate medium. Based on the ultrasonic transmission characteristics, when the acoustic impedance Z5 of the second adhesive layer is the same as the acoustic impedance Z3 of the first adhesive layer 2, the thickness S4 of the substrate layer is taken as λ. 基材层 The thickness S4 of the substrate layer is approximately a multiple of 1 / 2. When the acoustic impedance Z5 of the second adhesive layer is different from the acoustic impedance Z3 of the first adhesive layer 2, if the acoustic impedance Z4 of the substrate layer is between the acoustic impedance Z5 of the second adhesive layer and the acoustic impedance Z3 of the first adhesive layer 2, then the thickness S4 of the substrate layer is equal to the wavelength λ of the ultrasonic wave propagating in the substrate layer. 基材层 Approximately one-quarter of an odd multiple, i.e., the thickness S4 of the substrate layer is... If the acoustic impedance Z4 of the substrate layer is not between the acoustic impedance Z5 of the second adhesive layer and the acoustic impedance Z3 of the first adhesive layer 2, then the thickness S4 of the substrate layer is taken as λ. 基材层 The thickness S4 of the substrate layer is approximately a multiple of 1 / 2. With the substrate layer thickness S4 set as described above, the ultrasonic wave has a high penetration rate from the second adhesive layer of the fifth structural layer L5 to the first adhesive layer 2 of the third structural layer L3.

[0078] The substrate layer of the fourth structural layer L4, the first adhesive layer 2 of the third structural layer L3, and the first adhesive layer 1 of the second structural layer L2 are tightly bonded together, with the first adhesive layer 2 as the intermediate medium layer. Based on the ultrasonic wave transmission characteristics, when the acoustic impedance Z4 of the substrate layer and the acoustic impedance Z2 of the first adhesive layer 1 are the same, the thickness S3 of the first adhesive layer 2 is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer 2. 第一胶层2 The thickness S3 of the first adhesive layer 2 is approximately a multiple of 1 / 2. When the acoustic impedance Z4 of the substrate layer and the acoustic impedance Z2 of the first adhesive layer 1 are different, if the acoustic impedance Z3 of the first adhesive layer 2 is between the acoustic impedance Z4 of the substrate layer and the acoustic impedance Z2 of the first adhesive layer 1, then the thickness S3 of the first adhesive layer 2 is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer. 第一胶层2 Approximately a multiple of 1 / 4, that is, the thickness S3 of the first adhesive layer 2 is... If the acoustic impedance Z3 of the first adhesive layer 2 is not between the acoustic impedance Z4 of the substrate layer and the acoustic impedance Z2 of the first adhesive layer 1, then the thickness S3 of the first adhesive layer 2 is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer 2. 第一胶层2 The thickness S3 of the first adhesive layer 2 is approximately a multiple of 1 / 2. The thickness S3 of the first adhesive layer 2 is set according to the above method, and the ultrasonic wave has a high penetration rate when it is transmitted from the substrate layer of the fourth structural layer L4 to the first adhesive layer 1 of the second structural layer L2.

[0079] The three media—the first adhesive layer 2 of the third structural layer L3, the first adhesive layer 1 of the second structural layer L2, and the glass layer of the first structural layer L1—are tightly bonded together, with the first adhesive layer 1 serving as the intermediate medium. Based on the characteristics of ultrasonic wave transmission, when the acoustic impedance Z3 of the first adhesive layer 2 and the acoustic impedance Z1 of the glass layer are the same, the thickness S2 of the first adhesive layer 1 is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer 1. 第一胶层1 The thickness S2 of the first adhesive layer 1 is approximately a multiple of 1 / 2. When the acoustic impedance Z3 of the first adhesive layer 2 is different from that of the glass layer Z1, if the acoustic impedance Z2 of the first adhesive layer 1 is between the acoustic impedance Z3 of the first adhesive layer 2 and the acoustic impedance Z1 of the glass layer, then the thickness S2 of the first adhesive layer 1 is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer. 第一胶层1 The thickness S2 of the first adhesive layer is approximately one-quarter of an odd multiple, which is close to the value of the first adhesive layer. If the acoustic impedance Z2 of the first adhesive layer 1 is not between the acoustic impedance Z3 of the first adhesive layer 2 and the acoustic impedance Z1 of the glass layer, then the thickness S2 of the first adhesive layer 1 is equal to the wavelength λ of the ultrasonic wave propagating in the first adhesive layer 1. 第 一胶层1 The thickness S2 of the first adhesive layer 1 is approximately a multiple of 1 / 2. The thickness S2 of the first adhesive layer 1 is set according to the above method, and the ultrasonic wave has a high penetration rate when it is transmitted from the first adhesive layer 2 of the third structural layer L3 to the glass layer of the first structural layer L1.

[0080] The thickness of the glass layer in the first structural layer L1 is determined by the acoustic impedance of the first adhesive layer 1 in the second structural layer L2 and the acoustic impedance of the finger. The specific values ​​are similar to those of the glass layer thickness shown in Figure 1. To avoid repetition, they will not be described in detail here.

[0081] In an embodiment, as shown in FIG. 2, the mixed hardening adhesive layer comprises a first adhesive layer, a substrate layer and a second adhesive layer arranged in sequence, the first adhesive layer is a UV adhesive layer, the substrate layer is a PET layer, and the second adhesive layer is a silica gel layer; the thickness of the UV adhesive layer is λ UV , the thickness of the PET layer is λ PET , and the thickness of the silica gel layer is λsilica gel , wherein O, P and Q are positive integers.

[0082] Referring to FIG. 2, a screen protection film suitable for ultrasonic wave penetration is provided, which comprises a glass layer and a mixed hardening adhesive layer, the first adhesive layer is a UV adhesive layer, the substrate layer is a PET layer, and the second adhesive layer is a silica gel layer, i.e., the first structural layer L1 of the screen protection film is a glass layer, the thickness of which is S1; the second structural layer L2 is a UV adhesive layer, the thickness of which is S2; the third structural layer L3 is a PET layer, the thickness of which is S3; and the fourth structural layer L4 is a silica gel layer, the thickness of which is S4, wherein the layers L2 / L3 / L4 constitute a mixed hardening adhesive layer (i.e., an AB adhesive layer), the thickness of which is S AB胶 . In a specific implementation case, the acoustic impedances of the glass layer, the UV adhesive layer, the PET layer, the silica gel layer, and the finger are Z 玻璃 , Z UV胶 , Z PET , Z 硅胶 and Z 手指 , respectively. In an example, the acoustic impedance Z 玻璃 of the glass layer is 14.2 Mrayl, the acoustic impedance Z UV胶 of the UV adhesive layer is 3.6 Mrayl, the acoustic impedance Z PET of the PET layer is 3.2 Mrayl, the acoustic impedance Z 硅胶 of the silica gel layer is 1.3 Mrayl, and the acoustic impedance Z 手指 of the finger is less than the acoustic impedance Z 玻璃 of the glass layer, i.e., Z 玻璃 >Z UV胶 >Z PET >Z 硅胶 , Z 玻璃 >Z 手指 , and the acoustic impedance of the outer screen of the screen of the electronic device is also Z 玻璃 . From the outer screen of the screen of the electronic device, the thicknesses of the various structural layers of the screen protection film are determined as follows:

[0083] The outer screen of the screen of the electronic device, the silica gel layer of the fourth structural layer L4 and the PET layer of the third structural layer L3 are tightly attached, the intermediate medium layer is the silica gel layer, and the acoustic impedances of the three media satisfy ZPET > Z 硅胶 < Z 玻璃 Therefore, the thickness S4 of the silica gel layer of the fourth structural layer L4 is around 1 / 2 integer times of λ 硅胶 , i.e., the thickness of the silica gel layer is around , the ultrasonic wave penetration rate is high. In a specific embodiment, the value of Q is 1, and the thickness S4 of the silica gel layer is around 1 / 2 times of λ 硅胶 . In this way, the thickness S4 of the silica gel layer is set, and the ultrasonic wave has a high penetration rate when it is transmitted from the outer screen of the screen of the electronic device to the PET layer.

[0084] The silica gel layer of the fourth structural layer L4, the PET layer of the third structural layer L3, and the UV glue layer of the second structural layer L2 are closely attached, and the PET layer is the intermediate layer. The acoustic impedance of the three media satisfies Z 硅胶 < Z PET < Z UV胶 Therefore, the value of the PET layer of the third structural layer L3 is around 1 / 4 odd times of λ PET , i.e., the thickness of the PET layer is around , the ultrasonic wave penetration rate is high. In a specific embodiment, the value of P is 1, and the thickness S3 of the PET layer is around 1 / 4 times of λ PET . In this way, the thickness S3 of the PET layer is set, and the ultrasonic wave has a high penetration rate when it is transmitted from the silica gel layer of the fourth structural layer L4 to the UV glue layer of the second structural layer L2.

[0085] The PET layer of the third structural layer L3, the UV glue layer of the second structural layer L2, and the glass layer of the first structural layer L1 are closely attached, and the UV glue layer is the intermediate layer. The acoustic impedance of the three media satisfies Z PET < Z UV胶 < Z 玻璃 Therefore, the value of the UV glue layer of the second structural layer L2 is around 1 / 4 odd times of λ UV胶 , i.e., the thickness of the UV glue layer is around , the ultrasonic wave penetration rate is high. In a specific embodiment, the value of O is 1, and the thickness S2 of the UV glue layer is around 1 / 4 times of λ UV胶 . In this way, the thickness S2 of the UV glue layer is set, and the ultrasonic wave has a high penetration rate when it is transmitted from the PET layer of the third structural layer L3 to the glass layer of the first structural layer L1.

[0086] When the finger or other detection object presses on the ultrasonic detection area of the glass layer of the screen protection film, the UV glue layer of the second structural layer L2, the glass layer of the first structural layer L1, and the finger are closely attached, and the glass layer is the intermediate layer. The acoustic impedance of the three media satisfies Z UV胶 < Z 玻璃 Z 手指 Therefore, the thickness S1 of the glass layer of the first structure layer L1 is selected as a value near 1 / 2 integer times of λ 玻璃 , i.e., the thickness S1 of the glass layer is near 1 / 2 times of λ . In a specific embodiment, S is 1, and the thickness S1 of the glass layer is near 1 / 2 times of λ 玻璃 . In this way, the thickness S1 of the glass layer is set, and the penetration rate of the ultrasonic wave from the UV adhesive layer of the second structure layer L2 to the finger medium through the glass layer of the first structure layer L1 is high.

[0087] For example, when Q=1, P=1, O=1, and S=1, the thickness of the silica gel layer is near 1 / 2 integer times of λ 硅胶 ; the thickness of the PET layer is near 1 / 4 odd times of λ PET ; the thickness of the UV adhesive layer is near 1 / 4 odd times of λ UV胶 ; and the thickness of the glass layer is near 1 / 2 integer times of λ 玻璃 . This is beneficial to the penetration of the ultrasonic wave in the screen protection film, and more ultrasonic energy can be returned to the ultrasonic detection module. Considering the attenuation of the ultrasonic energy caused by the thickness of the material, the thickness of the glass layer and the silica gel layer is not recommended to be too large.

[0088] In an embodiment, when the frequency of the ultrasonic wave is 12 MHz, the thickness of the UV adhesive layer is 54 um-66 um or 162 um-198 um, the thickness of the PET layer is 45 um-55 um or 135 um-165 um, and the thickness of the silica gel layer is 45 um-55 um; when the frequency of the ultrasonic wave is 11 MHz, the thickness of the UV adhesive layer is 59 um-72 um or 176 um-215 um, the thickness of the PET layer is 51 um-61 um or 149 um-182 um, and the thickness of the silica gel layer is 49 um-59 um; and when the frequency of the ultrasonic wave is 10 MHz, the thickness of the UV adhesive layer is 65 um-79 um or 194 um-238 um, the thickness of the PET layer is 54 um-66 um or 162 um-198 um, and the thickness of the silica gel layer is 54 um-66 um.

[0089] As an example, when the ultrasonic fingerprint module is working, the frequency of the ultrasonic wave is f, and the speed of the ultrasonic wave in the medium is C, so the wavelength λ of the ultrasonic wave propagating in the medium is λ=T*C=C*1 / f. In the screen protection film shown in FIG. 2, the screen protection film includes a glass layer and a mixed hardening adhesive layer, and the mixed hardening adhesive layer includes a UV adhesive layer, a PET layer, and a silica gel layer. The speed of the ultrasonic wave in the glass layer, the UV adhesive layer, the PET layer, and the silica gel layer is shown in Table 1.

[0090] Table 1

[0091] In this example, the frequency f of the ultrasonic fingerprint module is 12 MHz, 11 MHz or 10 MHz, and the sound speed C of the ultrasonic wave in the glass layer, the UV glue layer, the PET layer and the silica gel layer is shown in Table 1. Due to the different ratios of materials, production processes and other factors affecting the sound speed in the glass layer, the UV glue layer, the PET layer and the silica gel layer, the sound speed of the ultrasonic wave in different structural layers has a certain error. The error of the above sound speed is limited within 10%, and the corresponding sound speed range is 0.9C-1.1C. Then, the wavelength of the ultrasonic wave in the glass layer, the UV glue layer, the PET layer and the silica gel layer is calculated by the wavelength calculation formula of the ultrasonic wave in the medium λ=T*C=C*1 / f, and the corresponding wavelength range is calculated. 玻璃 UV PET 硅胶 Finally, the thickness of the glass layer, the UV glue layer, the PET layer and the silica gel layer is determined according to the thickness of the glass layer , the thickness of the UV glue layer , the thickness of the PET layer and the thickness of the silica gel layer . In this example, the value of S is 1, the value of O is 1 or 2, the value of P is 1 or 2, and the value of Q is 1. The thickness of each structural layer is not too thick to cause attenuation of the ultrasonic wave energy. In this example, the thickness of each structural layer can be calculated based on the sound speed C of each structural layer and the frequency f of the ultrasonic fingerprint module, and the thickness range of each structural layer in the application is determined based on the product of the calculated thickness and (1±10%).

[0092] In an embodiment, if the frequency of the ultrasonic wave is 12 MHz, the thickness of the UV glue layer is 60 um or 180 um, the thickness of the PET layer is 50 um or 150 um, and the thickness of the silica gel layer is 50 um; if the frequency of the ultrasonic wave is 11 MHz, the thickness of the UV glue layer is 65 um or 195 um, the thickness of the PET layer is 55 um or 165 um, and the thickness of the silica gel layer is 54 um; if the frequency of the ultrasonic wave is 10 MHz, the thickness of the UV glue layer is 72 um or 216 um, the thickness of the PET layer is 60 um or 180 um, and the thickness of the silica gel layer is 60 um.

[0093] For example, when the ultrasonic wave works at 12 MHz, the thickness of each structural layer of the screen protection film in the application is partially combined as shown in Table 2 when the value of S is 1, the value of O is 1 or 2, the value of P is 1 or 2, and the value of Q is 1.

[0094] Table 2​​​

[0095] For example, when the ultrasonic wave works at 11 MHz, the thickness of each structural layer of the screen protection film in the present application is partially combined as shown in Table 3 when S is 1, O is 1 or 2, P is 1 or 2, and Q is 1:

[0096] Table 3

[0097] For example, when the ultrasonic wave works at 10 MHz, the thickness of each structural layer of the screen protection film in the present application is partially combined as shown in Table 4 when S is 1, O is 1 or 2, P is 1 or 2, and Q is 1:

[0098] Table 4

[0099] In an embodiment, as shown in FIG. 4, the thicknesses of at least three structural layers of the mixed hardening adhesive layer satisfy the thickness condition, the mixed hardening adhesive layer comprises two first adhesive layers, a substrate layer and a second adhesive layer arranged in sequence, the two first adhesive layers are a silica gel layer and an OCA adhesive layer arranged in sequence, the substrate layer is a PET layer, and the second adhesive layer is a UV adhesive layer; the thickness of the silica gel layer is λsilica gel is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer; the thickness of the OCA adhesive layer is λ OCA is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the OCA adhesive layer; the thickness of the PET layer is λ PET is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the PET layer; the thickness of the UV adhesive layer is λ UV is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the UV adhesive layer; wherein O, P, Q and R are positive integers.

[0100] Referring to FIG. 4, a screen protection film suitable for ultrasonic wave penetration is provided, the screen protection film comprises a glass layer and a mixed hardening adhesive layer, the first adhesive layer is a silica gel layer and an OCA adhesive layer arranged in sequence, the substrate layer is a PET layer, and the second adhesive layer is a UV adhesive layer, that is, the first structural layer L1 of the screen protection film is the glass layer, the thickness of which is S1; the second structural layer L2 is the silica gel layer, the thickness of which is S2; the third structural layer L3 is the OCA adhesive layer, the thickness of which is S3; the fourth structural layer L4 is the substrate layer, the thickness of which is S4; and the fifth structural layer L5 is the UV adhesive layer, the thickness of which is S5, wherein the L2 / L3 / L4 / L5 layers constitute the mixed hardening adhesive layer (i.e. the AB adhesive layer), the thickness of which is S AB胶 . In a specific implementation case, the acoustic impedance of the OCA adhesive layer is Z OCA .

[0101] In an example, the acoustic impedance of the OCA adhesive layer is about 1.9 Mrayl, i.e., Z 玻璃 > UV > PET > OCA > 硅胶 , 玻璃 > 手指 , from the outer screen of the screen of the electronic device, the thickness of each structural layer of the screen protection film is determined as follows:

[0102] The outer screen of the screen of the electronic device, the UV adhesive layer of the fifth structural layer L5, and the PET layer of the fourth structural layer L4 are closely attached, and the intermediate medium layer is the UV adhesive layer. The acoustic impedance of the three media satisfies: Z PET <Z UV <Z 玻璃 Therefore, the thickness S5 of the UV adhesive layer is about 1 / 4 of an odd multiple of the wavelength λ of the ultrasonic wave propagating in the UV adhesive layer, i.e., the thickness S5 of the UV adhesive layer is UV When the thickness S5 of the UV adhesive layer is , the ultrasonic wave penetration rate is high. By setting the thickness S5 of the UV adhesive layer in the above manner, the ultrasonic wave has a high penetration rate when it is transmitted from the outer screen of the screen of the electronic device to the PET layer of the fourth structural layer L4.

[0103] The UV adhesive layer of the fifth structural layer L5, the PET layer of the fourth structural layer L4, and the OCA adhesive layer of the third structural layer L3 are closely attached, and the intermediate medium layer is the PET layer. The acoustic impedance of the three media satisfies: Z OCA <Z PET <Z UV Therefore, the thickness S4 of the PET layer is about 1 / 4 of an odd multiple of the wavelength λ of the ultrasonic wave propagating in the PET layer, i.e., the thickness S4 of the PET layer is PET When the thickness S4 of the PET layer is , the ultrasonic wave penetration rate is high. According to the above manner of setting the thickness S4 of the PET layer, the ultrasonic wave has a high penetration rate when it is transmitted from the UV adhesive layer of the fifth structural layer L4 to the OCA adhesive layer of the third structural layer L2.

[0104] The PET layer of the fourth structural layer L4, the OCA adhesive layer of the third structural layer L3, and the silica gel layer of the second structural layer L2 are closely attached, and the intermediate medium layer is the OCA adhesive layer. The acoustic impedance of the three media satisfies: Z 硅胶 <Z OCA <Z PET Therefore, the thickness S3 of the OCA adhesive layer is about 1 / 4 of an odd multiple of the wavelength λ of the ultrasonic wave propagating in the OCA adhesive layer, i.e., the thickness S3 of the OCA adhesive layer is OCA When the thickness S3 of the OCA adhesive layer is When the ultrasonic wave penetrates the OCA adhesive layer, the ultrasonic wave penetrates the OCA adhesive layer at a high penetration rate. The thickness S3 of the OCA adhesive layer is set in the above manner, and when the ultrasonic wave is transmitted from the PET layer of the fourth structural layer L4 to the silica gel layer of the second structural layer L2, the ultrasonic wave has a high penetration rate.

[0105] The OCA adhesive layer of the third structural layer L3, the silica gel layer of the second structural layer L2, and the glass layer of the first structural layer L1 are closely attached, and the intermediate medium layer is the silica gel layer. The acoustic impedance of the three media satisfies: Z 玻璃 >Z 硅胶 <Z OCA The thickness S2 of the silica gel layer is about 1 / 2 integer times of the wavelength λ 硅胶 of the ultrasonic wave propagating in the silica gel layer, that is, the thickness S2 of the silica gel layer is about The thickness S2 of the silica gel layer is set in the above manner, and when the ultrasonic wave is transmitted from the UV adhesive layer of the third structural layer L3 to the glass layer of the first structural layer L1, the ultrasonic wave has a high penetration rate.

[0106] When the finger or other detection object presses on the ultrasonic detection area of the glass layer of the screen protection film, the silica gel layer of the second structural layer L2, the glass layer of the first structural layer L1, and the finger are closely attached, and the glass layer is the intermediate layer. The acoustic impedance of the three media satisfies: Z 手指 <Z 玻璃 >Z 硅胶 , the thickness S1 of the glass layer is about 1 / 2 integer times of the wavelength λ 玻璃 , that is, the thickness S1 of the glass layer is about When k=1, the thickness S1 of the glass layer is about The thickness S1 of the glass layer is set in the above manner, and the ultrasonic wave has a high penetration rate when transmitted from the silica gel layer of the second structural layer L2 to the finger medium.

[0107] For example, when R=1, Q=1, P=1, O=1, and S=1, the thickness of the UV adhesive layer is about an odd multiple of 1 / 4 λ UV , the thickness of the PET layer is about an odd multiple of 1 / 4 λ PET , the thickness of the OCA adhesive layer is about an integer multiple of 1 / 4 λ OCA , the thickness of the silica gel layer is about an integer multiple of 1 / 2 λ 硅胶 , and the thickness of the glass layer is about an integer multiple of 1 / 2 λ 玻璃 , which is conducive to the penetration of the ultrasonic wave in the screen protection film, and more ultrasonic energy can be returned to the ultrasonic detection module. Considering the attenuation of ultrasonic energy due to material thickness, the thickness of the glass layer and the silica gel layer is not recommended to be too large.

[0108] In an embodiment, if the frequency of the ultrasonic wave is 12 MHz, the thickness of the silica gel layer is 45-55 um or 90-110 um, the thickness of the OCA adhesive layer is 34-42 um or 104-127 um, the thickness of the PET layer is 45-55 um, and the thickness of the UV adhesive layer is 54-66 um or 162-198 um; if the frequency of the ultrasonic wave is 11 MHz, the thickness of the silica gel layer is 50-61 um or 99-121 um, the thickness of the OCA adhesive layer is 37-45 um or 113-138 um, the thickness of the PET layer is 50-61 um, and the thickness of the UV adhesive layer is 59-72 um or 177-217 um; if the frequency of the ultrasonic wave is 10 MHz, the thickness of the silica gel layer is 54-66 um or 108-132 um, the thickness of the OCA adhesive layer is 41-51 um or 124-152 um, the thickness of the PET layer is 54-66 um, and the thickness of the UV adhesive layer is 65-79 um or 194-237 um.

[0109] As an example, in the screen protection film shown in FIG. 4, the screen protection film includes a glass layer and a mixed hardening adhesive layer including a silica gel layer, an OCA adhesive layer, a PET layer, and a UV adhesive layer, wherein the sound velocity of the ultrasonic wave in the glass layer, the silica gel layer, the OCA adhesive layer, the PET layer, and the UV adhesive layer is as shown in Table 5:

[0110] Table 5

[0111] In this example, it is assumed that the frequency f of the ultrasonic fingerprint module is 12 MHz, 11 MHz, or 10 MHz; the sound velocity C of the ultrasonic wave in the glass layer, the silica gel layer, the OCA adhesive layer, the PET layer, and the UV adhesive layer during propagation is as shown in Table 5; the error of the above-mentioned sound velocity is limited within 10%, and the corresponding sound velocity range is 0.9C-1.1C; then, the wavelength of the ultrasonic wave propagating in the glass layer, the silica gel layer, the OCA adhesive layer, the PET layer, and the UV adhesive layer is calculated respectively by the wavelength calculation formula of the ultrasonic wave propagating in the medium λ=T*C=C*1 / f, and the corresponding wavelength ranges are calculated respectively. 玻璃 硅胶 OCA PET UV Finally, according to the thickness of the glass layer being the thickness of the silica gel layer being the thickness of the OCA adhesive layer being the thickness of the PET layer being the thickness of the UV adhesive layer being ​​​​The thicknesses of the glass layer, the silica gel layer, the OCA adhesive layer, the PET layer and the UV adhesive layer are determined respectively. In this example, when the value of S is 1, the value of O is 1 or 2, the value of P is 1 or 2, the value of Q is 0, and the value of R is 1 or 2, the thicknesses of the structural layers are not too thick to cause attenuation of ultrasonic energy. In this example, the thicknesses of the structural layers can be calculated based on the sound velocities C of the structural layers and the frequency f at which the ultrasonic fingerprint module works, and then the thickness ranges of the structural layers in the present application are determined based on the calculated thicknesses and the products of (1±10%).

[0112] In an embodiment, when the frequency of the ultrasonic wave is 12 MHz, the thickness of the silica gel layer is 50 um or 100 um, the thickness of the OCA adhesive layer is 38 um or 115 um, the thickness of the PET layer is 50 um, and the thickness of the UV adhesive layer is 60 um or 180 um; when the frequency of the ultrasonic wave is 11 MHz, the thickness of the silica gel layer is 55 um or 110 um, the thickness of the OCA adhesive layer is 41 um or 125 um, the thickness of the PET layer is 55 um, and the thickness of the UV adhesive layer is 65 um or 197 um; when the frequency of the ultrasonic wave is 10 MHz, the thickness of the silica gel layer is 60 um or 120 um, the thickness of the OCA adhesive layer is 46 um or 138 um, the thickness of the PET layer is 60 um, and the thickness of the UV adhesive layer is 72 um or 215 um.

[0113] In this embodiment, the calculated thicknesses can have a tolerance of ±10 um after process processing, and when the tolerance is ±5 um, the ultrasonic wave attenuates more weakly and has better performance. For example, when the ultrasonic wave works at 12 MHz, and the value of S is 1, the value of O is 1 or 2, the value of P is 1 or 2, the value of Q is 1, and the value of R is 1 or 2, the thickness combinations of the structural layers of the screen protection film in the present application are shown in Table 6:

[0114] Table 6

[0115] For example, when the ultrasonic wave works at 11 MHz, and the value of S is 1, the value of O is 1 or 2, the value of P is 1 or 2, the value of Q is 1, and the value of R is 1 or 2, the thickness combinations of the structural layers of the screen protection film in the present application are shown in Table 7:

[0116] Table 7

[0117] For example, when the ultrasonic wave works at 10 MHz, and the value of S is 1, the value of O is 1 or 2, the value of P is 1 or 2, the value of Q is 1, and the value of R is 1 or 2, the thickness combinations of the structural layers of the screen protection film in the present application are shown in Table 8:

[0118] Table 8

[0119] In an embodiment, as shown in FIG. 5, the thickness of at least three structural layers of the mixed hardening adhesive layer satisfies the thickness condition, the mixed hardening adhesive layer comprises two first adhesive layers, a substrate layer and a second adhesive layer arranged in sequence, the two first adhesive layers are a UV adhesive layer and an OCA adhesive layer arranged in sequence, the substrate layer is a PET layer, and the second adhesive layer is a silica gel layer; the thickness of the UV adhesive layer is λ UV the wavelength of the ultrasonic wave propagating in the UV adhesive layer; the thickness of the OCA adhesive layer is λ OCA the wavelength of the ultrasonic wave propagating in the OCA adhesive layer; the thickness of the PET layer is λ PET the wavelength of the ultrasonic wave propagating in the PET layer; the thickness of the silica gel layer is λ UV the wavelength of the ultrasonic wave propagating in the silica gel layer; wherein O, P, Q and R are positive integers.

[0120] As an example, the mixed hardening adhesive layer shown in FIG. 5 and the mixed hardening adhesive layer shown in FIG. 4 both comprise a UV adhesive layer, an OCA adhesive layer, a PET layer and a silica gel layer, and the difference between the two is that the positions of the UV adhesive layer and the silica gel layer are interchanged. As can be known from the example shown in FIG. 4, the acoustic impedance relationship of different structural layers is as follows: Z 玻璃 >Z UV >Z PET >Z OCA >Z 硅胶 Based on the above acoustic impedance relationship, the thickness determination process of different structural layers is as follows:

[0121] When the i-th structural layer is a UV adhesive layer, the i-1-th structural layer is a glass layer, and the i+1-th structural layer is an OCA adhesive layer, it can be known from Z 玻璃 >Z UV >Z OCA that the acoustic impedance of the i-th structural layer is between the acoustic impedance of the i-1-th structural layer and the acoustic impedance of the i+1-th structural layer. Therefore, when the thickness of the UV adhesive layer is , the ultrasonic wave penetration rate is high.

[0122] When the i-th structural layer is an OCA adhesive layer, the i-1-th structural layer is a UV adhesive layer, and the i+1-th structural layer is a PET layer, it can be known from Z UV >Z PET >Z OCA that the acoustic impedance of the i-th structural layer is not between the acoustic impedance of the i-1-th structural layer and the acoustic impedance of the i+1-th structural layer. Therefore, when the thickness of the OCA adhesive layer is , the ultrasonic wave penetration rate is high.

[0123] When the i-th structural layer is a PET layer, the (i-1)-th structural layer is an OCA adhesive layer, and the (i+1)-th structural layer is a silicone layer, as determined by Z... PET >Z OCA >Z 硅胶 It can be seen that the acoustic impedance of the i-th structural layer is not between the acoustic impedance of the (i-1)-th structural layer and the acoustic impedance of the (i+1)-th structural layer. Therefore, when the thickness of the PET layer is... At that time, the ultrasonic wave has a high penetration rate.

[0124] When the i-th structural layer is a silicone layer, the (i-1)-th structural layer is a PET layer, and the (i+1)-th structural layer is the outer screen of the screen. The outer screen is generally made of glass, and Z... 玻璃 >Z PET >Z 硅胶 It can be seen that the acoustic impedance of the i-th structural layer is not between the acoustic impedance of the (i-1)-th structural layer and the acoustic impedance of the (i+1)-th structural layer. Therefore, when the thickness of the silicone layer is... At that time, the ultrasonic wave has a high penetration rate.

[0125] In one embodiment, a release film is provided on each side of the mixed hardening adhesive layer.

[0126] As an example, a release film is provided on each side of the mixed-curing adhesive layer. When the release film on the first first adhesive layer of the mixed-curing adhesive layer is peeled off, the first first adhesive layer is attached to the glass layer of the screen protector. When the release film on the last first adhesive layer of the mixed-curing adhesive layer is peeled off, the last second adhesive layer is attached to the outer screen of the electronic device.

[0127] One embodiment of this application provides a screen protector for attaching to the outer screen of an electronic device with under-display ultrasonic fingerprint recognition. The screen protector includes a glass layer and the aforementioned mixed-hardening adhesive layer: a first adhesive layer of the mixed-hardening adhesive layer is attached to the glass layer, and a last adhesive layer of the mixed-hardening adhesive layer is attached to the outer screen; the thickness of the glass layer is [missing information]. Where λglass is the wavelength of the longitudinal wave of the ultrasound propagating through the glass layer, and S is a positive integer.

[0128] As an example, a screen protector includes a glass layer and a mixed-curing adhesive layer adhered to the glass layer. This screen protector can be entirely attached to the outer screen of an electronic device. When a finger or other object presses against the ultrasonic testing area on the glass layer of the screen protector, the three media—the first adhesive layer in the second structural layer L2, the glass layer in the first structural layer L1, and the finger—are tightly bonded together. The glass layer serves as the intermediate layer. Since the acoustic impedance Z1 of the glass layer is generally not greater than the acoustic impedance Z2 of the first adhesive layer 1 and the acoustic impedance Z of the finger… s Therefore, the thickness S1 of the glass layer is taken as λ. 玻璃 The thickness S1 of the glass layer is approximately a multiple of 1 / 2. When S is 1, the thickness S1 of the glass layer is: By setting the thickness S1 of the glass layer in the above manner, the penetration rate of ultrasonic waves transmitted from the first adhesive layer of the second structural layer L2 to the finger medium is high.

[0129] In one embodiment, if the frequency of the ultrasonic wave is 12MHz, the thickness of the glass layer is 221um-270um; or, if the frequency of the ultrasonic wave is 11MHz, the thickness of the glass layer is 243um-297um; or, if the frequency of the ultrasonic wave is 10MHz, the thickness of the glass layer is 261um-319um.

[0130] The speed of sound in a glass layer is called the speed of sound C. 玻璃 = 5.9 μm / ns. Limiting the error of the above sound velocity to within 10%, the corresponding sound velocity range is determined to be 0.9C. 玻璃 -1.1C 玻璃 Then, based on the wavelength λ of the ultrasonic wave propagating in the glass layer... 玻璃 =T*C 玻璃 =C 玻璃 *1 / f, calculate the wavelength λ of the ultrasonic wave propagating through the glass layer. 玻璃 The corresponding wavelength range; finally, based on The thickness range of the glass layer is determined. Specifically, when S is 1, the thickness range of the glass layer is determined as shown above.

[0131] In one embodiment, if the frequency of the ultrasonic wave is 12 MHz, the thickness of the glass layer is 245 μm; or, if the frequency of the ultrasonic wave is 11 MHz, the thickness of the glass layer is 270 μm; or, if the frequency of the ultrasonic wave is 10 MHz, the thickness of the glass layer is 290 μm.

[0132] As an example, the speed of sound in the glass layer is 5.9 μm / ns, based on the wavelength λ of the ultrasonic wave propagating in the glass layer. 玻璃 =T*C 玻璃 =C 玻璃 *1 / f, calculate the wavelength λ of the ultrasonic wave propagating through the glass layer. 玻璃 Then, based on Determine the thickness of the glass layer. For example, when S is 1, if the frequency of the ultrasound is 12MHz, the thickness of the glass layer is determined to be 245um; if the frequency of the ultrasound is 11MHz, the thickness of the glass layer is determined to be 270um; if the frequency of the ultrasound is 10MHz, the thickness of the glass layer is determined to be 290um.

[0133] In an embodiment, a release film is arranged on the last second adhesive layer of the mixed hardening adhesive layer.

[0134] As an example, in the screen protection film, the first first adhesive layer of the mixed hardening adhesive layer is attached to the glass layer of the screen protection film, and the release film on the last second adhesive layer of the mixed hardening adhesive layer is attached to the outer screen of the screen of the electronic device when the release film is peeled off.

[0135] An embodiment of the present application provides an electronic device, which comprises the screen protection film in the above-mentioned embodiments and a screen, and the screen protection film is attached to the outer screen of the screen.

[0136] Referring to FIG. 6, the basic principle of ultrasonic under-screen fingerprint identification is that an ultrasonic fingerprint module is installed below an OLED screen, ultrasonic waves emitted by the ultrasonic fingerprint module pass through the OLED screen and reach the surface of a finger, and the fingerprint of the finger reflects the ultrasonic waves. Because the reflectivity of the valleys and ridges of the fingerprint to the ultrasonic waves is different, the reflected echo passes through the OLED screen and is received by the ultrasonic fingerprint module, and a fingerprint image can be obtained according to the difference in echo. Referring to FIG. 7, the structure of a mobile phone protection film comprises a glass layer (Glass) and a mixed hardening adhesive layer (AB adhesive), and the mixed hardening adhesive layer comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence. The optical adhesive layer (OCA, Optically Clear Adhesive) and the silica gel layer have adhesion and are respectively attached to both sides of the substrate layer, and therefore are called a mixed hardening adhesive layer.

[0137] In the embodiment, the substrate layer can be made of various organic matters, and the substrate layer plays a role of a carrier plate. For example, the substrate layer can be a PET (Polyethylene terephthalate) film. PET is an abbreviation of polyethylene terephthalate, and its full name is polyethylene terephthalate, also known as polyester. PET is a common plastic material, which has good transparency, mechanical properties and chemical corrosion resistance.

[0138] When the mobile phone protection film is attached to the surface of the screen, the mobile phone protection film and the screen cannot be completely attached around the screen, and a "white edge" will be generated. In the scenario of a curved screen, because the curvature of the full screen and the mobile phone protection film is inconsistent, the "white edge" will become very serious. In order to eliminate the "white edge", it is necessary to thicken the optical adhesive layer, because the optical adhesive layer is relatively soft, and the optical adhesive layer can be used to absorb the white edge gap, so as to eliminate the white edge. Generally, the optical adhesive layer needs to reach a thickness of 250 um to solve the problem of the "white edge". However, because the optical adhesive layer has relatively large attenuation to ultrasonic waves, when the optical adhesive layer is relatively thick, the attenuation has a great influence on the performance of ultrasonic under-screen fingerprint identification.

[0139] Further, Table 9 is the sound velocity of the materials used in each layer of the glass layer and the mixed hardening glue layer in this embodiment. The glass layer is a high acoustic impedance material, for example, the acoustic impedance thereof is 14 Mrayl, the constituent materials of the mixed hardening glue layer are all low acoustic impedance materials, the acoustic impedance of the optical glue layer is 2 Mrayl, and the acoustic impedance of the substrate layer is 3.2 Mrayl. Generally, 5 is taken as the demarcation line between high acoustic impedance materials and low acoustic impedance materials.

[0140] Table 9

[0141] In this embodiment, the sound velocity of the glass is 5.7 um / ns, but in the embodiment of Table 1, the sound velocity of the glass is 5.9 um / ns, which is caused by the slight difference in the material of the glass.

[0142] When the acoustic wave is transmitted from medium 1 to medium 2, according to the law of acoustic wave reflection: wherein Z1 and Z2 are the acoustic impedance of medium 1 and medium 2 respectively, and rf is the ultrasonic wave reflectivity when the acoustic wave is transmitted from medium 1 to medium 2. If the average acoustic impedance of the mixed hardening glue layer is estimated to be 2, then when the acoustic wave is transmitted from the glass layer to the mixed hardening glue layer, the ultrasonic wave reflectivity rf = (14-2) / (14+2) = 75%, that is, the ultrasonic wave reflectivity of reflection 1 in FIG. 2 is 75%. Similarly, it can be obtained that the ultrasonic wave reflectivity of reflection 1 ≈ the ultrasonic wave reflectivity of reflection 2 ≈ the ultrasonic wave reflectivity of reflection 3 ≈ the ultrasonic wave reflectivity of reflection 4 = 75%. Therefore, the application of the tempered protective film on the screen surface will cause that only a small proportion of the finger reflected ultrasonic wave can be received by the ultrasonic fingerprint module, resulting in a sharp deterioration of the fingerprint recognition effect.

[0143] In order to improve the penetration rate of ultrasonic waves in different media, the thickness of the material needs to be specially designed based on the acoustic characteristics thereof. When the ultrasonic wave penetrates medium 2 from medium 1 and then enters medium 3, the ultrasonic wave penetration rate T1 is shown in Formula One: Formula One. Wherein Z1 and Z2, Z3 are the acoustic impedance of medium 1 and medium 2, medium 3 respectively, D is the thickness of medium 2, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave in medium 2.

[0144] When D is exactly N*λ2 / 2, wherein N is a positive integer and λ2 is the wavelength of the ultrasonic wave in medium 2, T1 has a maximum value of When the ultrasonic wave is incident on medium 1 from medium 3, the same rule applies.

[0145] And in this embodiment, the medium 1 is a finger, the medium 2 is a glass layer, the medium 3 is a mixed hardening glue layer, and the ultrasonic wave frequency is 11MHz. Referring to FIG. 8, when the glass layer is about 250um and 500um, the ultrasonic wave penetration rate T1 has a maximum value, and the half wave length is just 250um. When the thickness D of the medium 2 is less than λ2 / 8, the ultrasonic wave penetration rate T1 decreases rapidly with the increase of the thickness. At the same time, when the thickness of the medium 2 is far away from N*λ2 / 2, the ultrasonic wave penetration rate T1 will decrease significantly, and when the thickness D of the medium 2 is equal to λ2 / 4+N*λ2 / 2, the ultrasonic wave penetration rate T1 has a minimum value.

[0146] Through the above analysis, it can be known that when the thickness of the medium 2 satisfies D=N*λ2 / 2, the ultrasonic wave penetration rate T1 is relatively high, or D<λ2 / 8 and the smaller the thickness, the higher the ultrasonic wave penetration rate T1. When the thickness of the medium 2 is far away from D=λ2 / 4+N*λ2 / 2, the ultrasonic wave penetration rate T1 can be avoided to decrease significantly.

[0147] When the thickness of the glass layer is less than λ2 / 8 and the smaller the thickness, the strength of the glass layer is not enough to protect the screen well, when the thickness of the glass layer is λ2 / 2, the thickness of the glass layer can be ensured to provide a protection effect on the screen, when the thickness of the glass layer is D=N*λ2 / 2 and N is greater than or equal to 2, the glass layer is too thick, which may cause the ultrasonic wave propagation path to be too long to cause signal strength loss, in addition, the glass is too thick to affect the user experience, therefore, when the thickness of the glass layer is λ2 / 2, the protection effect on the screen can be ensured and better user experience can be provided. Specifically, the thickness of the glass layer can be 250um. In addition, the ultrasonic wave penetration rate is more sensitive to the thickness of the glass, therefore, the thickness of the glass is designed to have a floating range of plus or minus 10%.

[0148] Referring to FIG. 9, the application provides a screen protection film applied to a screen with an under-screen ultrasonic wave fingerprint identification function. The screen protection film comprises a glass layer and a mixed hardening glue layer, and the mixed hardening glue layer is used to attach the glass layer to the surface of the screen.

[0149] Specifically, one side of the mixed hardening glue layer is used to set a release film, or both sides of the mixed hardening glue layer are used to set a release film.

[0150] When one side of the mixed hardening adhesive layer is used to set the release film, the other side of the mixed hardening adhesive layer is directly attached to the glass layer. When the release film is peeled off from one side of the mixed hardening adhesive layer, the mixed hardening adhesive layer attaches the glass layer to the surface of the screen. When attaching, the semi-cured photosensitive adhesive layer is attached to the glass layer, and the silica gel layer is attached to the screen.

[0151] The mixed hardening adhesive layer comprises a semi-cured photosensitive adhesive layer, a substrate layer and a silica gel layer arranged in sequence.

[0152] The photosensitive adhesive (UV adhesive) includes semi-cured and cured. The semi-cured photosensitive adhesive layer needs to be irradiated by UV light to achieve curing. The cured photosensitive adhesive layer itself does not have an adhesive layer, and needs an additional liquid photosensitive adhesive layer to achieve attachment, which is more troublesome for attaching the screen.

[0153] The semi-cured photosensitive adhesive layer is used to replace the optical surface layer in the embodiment of the application, thereby avoiding the attenuation of ultrasonic waves caused by the thick optical adhesive layer, improving the influence of the tempered protective film on ultrasonic under-screen fingerprint recognition, and better achieving fingerprint recognition.

[0154] The semi-cured photosensitive adhesive layer in the embodiment of the application normally presents a mechanical state similar to that of the optical adhesive layer, has good flexibility, and avoids the problem of easy flow and difficult control of the conventional liquid semi-cured photosensitive adhesive layer.

[0155] After the tempered film of the application is attached to the screen, the entire film is irradiated by UV light to completely cure the semi-cured photosensitive adhesive layer. The completely cured layer of the adhesive presents a solid state, and the semi-cured photosensitive adhesive layer in the solid state significantly reduces the attenuation of ultrasonic waves, thereby solving the problem of ultrasonic wave attenuation caused by the optical adhesive layer.

[0156] The embodiment of the application also provides a mixed hardening adhesive layer. The mixed hardening adhesive layer comprises a semi-cured photosensitive adhesive layer, a substrate layer and a silica gel layer arranged in sequence. The two sides of the mixed hardening adhesive layer are respectively provided with an upper release film and a lower release film.

[0157] When one side of the mixed hardening adhesive layer is used to set the release film, the other side of the mixed hardening adhesive layer is directly attached to the glass layer. When the release film is peeled off from one side of the mixed hardening adhesive layer, the mixed hardening adhesive layer attaches the glass layer to the surface of the screen.

[0158] When the two sides of the mixed hardening adhesive layer are used to set the release film, one side of the mixed hardening adhesive layer is attached to the surface of the screen when the release film is peeled off from one side of the mixed hardening adhesive layer. The other side of the mixed hardening adhesive layer is attached to the surface of the screen when the release film is peeled off from the other side of the mixed hardening adhesive layer.

[0159] In a specific implementation of the first embodiment of the present application, the propagation time of the ultrasonic wave in the mixed hardening adhesive layer is equal to or the sum of the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer and the substrate layer is equal to or the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer is equal to wherein N is a positive integer, and T0 is the period of the ultrasonic wave. Wherein D UV is the thickness of the semi-cured photosensitive adhesive layer, u UV is the wave velocity of the longitudinal wave of the ultrasonic wave propagating in the semi-cured photosensitive adhesive layer, D PET is the thickness of the substrate layer, u PET is the wave velocity of the longitudinal wave of the ultrasonic wave propagating in the substrate layer, D SL is the thickness of the silica gel layer, and u SL is the wave velocity of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer. In one embodiment, the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer is equal to i.e. the thickness of the semi-cured photosensitive adhesive layer is For example, the thickness of the semi-cured photosensitive adhesive layer is or an integer multiple thereof, and specifically, a certain error is allowed, for example, it can be 130um or 260um.

[0160] In one embodiment, the sum of the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer and the substrate layer is equal to For example, the thickness of the semi-cured photosensitive adhesive layer is 60um, and the thickness of the substrate layer is 50um, at this time, the sum of the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer and the substrate layer is equal to 50um / (2.4um / ns)+60um / (2.9um / ns)=41.5ns, and the period T0 is about 90.91ns, and the integer multiple of the half period is 45.5ns, and in this embodiment, the thickness value allows a certain error.

[0161] In one embodiment, the propagation time of the ultrasonic wave in the mixed hardening adhesive layer +50um / (2.4um / ns)+50um / (1.2um / ns)=152ns, i.e. three times of the half period is 136.4ns, and the error is about 11.4%.

[0162] In this embodiment, the error of the propagation time is less than 15%, so that the attenuation of the ultrasonic wave energy can be reduced. In the above embodiments, the specific implementation thickness combination is shown in Table 2:

[0163] Table 10

[0164] From the above analysis, the propagation time of the ultrasonic wave in the mixed hardening glue layer is equal to The ultrasonic wave penetration rate is relatively high.

[0165] If the propagation time of the ultrasonic wave in the mixed hardening glue layer cannot meet The propagation time of the ultrasonic wave in the semi-solidified photosensitive glue layer and the substrate layer or the substrate layer and the silica gel layer or the semi-solidified photosensitive glue layer is equal to

[0166] Specifically, if the frequency of the ultrasonic wave is 11MHz; the propagation time of the ultrasonic wave in the mixed hardening glue layer is equal to The material of the silica gel layer has a greater influence on the penetration rate of the ultrasonic wave, that is, the penetration rate of the ultrasonic wave is more sensitive to the material of the silica gel layer, so the thickness of the silica gel layer is set to be thinner than the optical glue layer and the substrate layer, which can reduce the attenuation of the ultrasonic wave energy. For example, the thickness of the semi-solidified photosensitive glue layer is 260um; the thickness of the substrate layer is 50um; and the thickness of the silica gel layer is 50um.

[0167] In some specific implementations of the embodiments of the present application, if the sum of the propagation time of the ultrasonic wave in the semi-solidified photosensitive glue layer and the substrate layer is equal to The thickness of the silica gel layer is equal to λ1 / 2*M or less than λ1 / 8. Alternatively, if the propagation time of the ultrasonic wave in the semi-solidified photosensitive glue layer is equal to The thickness of the silica gel layer is equal to λ1 / 2*M or less than λ1 / 8, and the thickness of the substrate layer is equal to λ4 / 2*M or less than λ4 / 8; wherein M is a positive integer, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, and λ4 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the substrate layer.

[0168] The embodiments of the present application further set the thickness of the semi-solidified photosensitive glue layer, the substrate layer and the silica gel layer, so as to better improve the influence of the tempered protective film on the ultrasonic wave under-screen fingerprint identification and improve the effect of fingerprint identification.

[0169] In a specific implementation of the embodiment one of the application, the mixed hardened adhesive layer comprises a semi-cured photosensitive adhesive layer, a substrate layer and a silica gel layer arranged in sequence, the thickness of the semi-cured photosensitive adhesive layer is equal to λ2 / 2*M or less than λ2 / 8, the thickness of the substrate layer is equal to λ4 / 2*M or less than λ4 / 8, and the thickness of the silica gel layer is equal to λ1 / 2*M or less than λ1 / 8, wherein M is a positive integer, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the cured semi-cured photosensitive adhesive layer, and λ4 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the substrate layer.

[0170] The embodiment of the application improves the influence of the tempered protective film on the ultrasonic under-screen fingerprint identification by setting the thicknesses of the semi-cured photosensitive adhesive layer, the substrate layer and the silica gel layer, and better realizes the fingerprint identification.

[0171] In the embodiment, if the thickness error of the optical adhesive layer, the silica gel layer and the substrate layer is controlled within 10%, the attenuation of the ultrasonic wave is less, and the fingerprint identification effect can be further improved.

[0172] In some other specific implementations of the embodiment of the application, referring to FIG. 10, the mixed hardened adhesive layer further comprises an optical adhesive layer arranged between the semi-cured photosensitive adhesive layer and the substrate layer, that is, the mixed hardened adhesive layer comprises a semi-cured photosensitive adhesive layer, an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence.

[0173] The embodiment of the application avoids the attenuation of the optical adhesive layer on the ultrasonic wave by arranging the semi-cured photosensitive adhesive layer and the optical adhesive layer, and making the arranged optical adhesive layer thinner than the optical adhesive layer alone, thereby improving the influence of the tempered protective film on the ultrasonic under-screen fingerprint identification and better realizing the fingerprint identification.

[0174] In some other specific implementations of the embodiment of the application, the thickness of the optical adhesive layer is equal to λ5 / 2*R, and the thickness of the semi-cured photosensitive adhesive layer is λ2 / 4 or 3λ2 / 4. Alternatively, the sum of the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer and the optical adhesive layer is equal to wherein R and S are positive integers, T0 is the period of the ultrasonic wave, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the cured semi-cured photosensitive adhesive layer, and λ5 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer.

[0175] In one embodiment, the thickness of the optical adhesive layer is equal to λ5 / 2*R, λ5 is for example 163.64 microns, the thickness of the optical adhesive layer can be an integer multiple of 81.82 microns, for example, it can be 80 microns, and the thickness of the semi-cured photosensitive adhesive layer is λ2 / 4 or 3λ2 / 4, λ2 is for example about 263.64 microns, the thickness of the semi-cured photosensitive adhesive layer can be 65.91 um or 197.73 um, in this embodiment, the thickness can have an error range of for example 20%, the thickness of the semi-cured photosensitive adhesive layer can be 60 um or 180 um.

[0176] In one embodiment, the sum of the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer and the optical adhesive layer is equal to For example, D UV is 60 um, D OCR is 120 um, The period T0 is about 90.9 ns, in this embodiment, S can be equal to 2. For another example, the propagation time of the ultrasonic wave in the semi-cured photosensitive adhesive layer is equal to The propagation time of the ultrasonic wave in the optical adhesive layer is equal to The thickness of the semi-cured photosensitive adhesive layer is The thickness of the optical adhesive layer is

[0177] In one embodiment, the sum of the propagation time of the ultrasonic wave in the substrate layer and the silicone layer is is equal to wherein W is a positive integer, and T0 is the period of the ultrasonic wave.

[0178] Taking the specific thickness of the material as an example, the thickness of the silicone layer can be 50 um, the thickness of the substrate layer can be 20 um, and the sum of the propagation time of the ultrasonic wave in the silicone layer and the substrate layer is The period T0 is about 90.9 ns, in this embodiment, W can be equal to 1, and the error of the sum of the propagation time is about 10%. In this embodiment, the thickness of the semi-cured photosensitive adhesive layer and the optical adhesive layer can meet the requirements mentioned in the previous embodiments, that is, the thickness of the semi-cured photosensitive adhesive layer is an odd multiple of λ2 / 4, for example, the thickness is λ2 / 4 or 3λ2 / 4, which can be an odd multiple of 65.9 um, in this embodiment, the thickness can have a certain error range, and in Table 3, taking an integer as an example, the thickness of the semi-cured photosensitive adhesive layer can be 60 um, 180 um and 200 um. In addition, the thickness of the optical adhesive layer is equal to λ5 / 2*R, and the thickness of the optical adhesive layer is about an integer multiple of 81.8 um, for example, 80 um, 160 um, 240 um, as shown in Table 3. In one embodiment, the sum of the propagation time of the ultrasonic wave in the optical adhesive layer and the substrate layer is equal to Where T is a positive integer. For example, if the thickness of the optical adhesive layer is 180 μm and the thickness of the substrate layer is 75 μm, then the sum of the propagation times of the ultrasonic wave in the optical adhesive layer and the substrate layer is... The time difference is 180µm / (1.8µm / ns) + 75µm / (2.4µm / ns) = 131.2ns, and the period T0 is approximately 90.91ns. A multiple of half a period, i.e., a multiple of 45.5ns, is used. In this embodiment, T equals 3, and the propagation time error is 3.88%. For example, if the thickness of the optical adhesive layer is 120µm and the thickness of the substrate layer is 50µm, then the sum of the propagation times of the ultrasonic wave in the optical adhesive layer and the substrate layer... The time is equal to 120um / (1.8um / ns) + 50um / (2.4um / ns) = 87.5ns, and the period T0 is approximately 90.91ns. A multiple of half a period, i.e., a multiple of 45.5ns, is required. In this embodiment, T equals 2, and the propagation time error is 3.85%. Specifically, a certain degree of error is allowed in the specific thickness value; preferably, the error can be within 5%.

[0179] In one embodiment, the propagation time of the ultrasonic wave in the hybrid hardened adhesive layer +80um / (1.8um / ns)+50um / (2.4um / ns)+50um / (1.2um / ns)=141.3ns, which means three times the half-cycle is 136.4ns, so the error is about 3.6%.

[0180] In this embodiment, the propagation time error is less than 10%, thus reducing the attenuation of ultrasonic energy. The specific thickness combinations implemented in the above embodiments are shown in Table 3.

[0181] Table 11

[0182] The embodiments of this application employ the aforementioned thickness settings, which can better reduce the attenuation of ultrasonic waves by the optical adhesive layer and the semi-cured photosensitive adhesive layer, further improving the impact of the tempered glass protective film on ultrasonic under-display fingerprint recognition, and achieving better fingerprint recognition. It should be noted that the quality of the received ultrasonic signal is optimal when each layer of the tempered glass film meets the above requirements for thickness or propagation time.

[0183] Currently, the application frequency of ultrasonic under-display fingerprint sensors is generally 10-13MHz. Considering the manufacturing process of the glass layer, the thickness of the glass layer is set to λ3 / 2, where λ3 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the glass.

[0184] Specifically, the thickness of the glass layer is 250 μm.

[0185] Due to the process requirement of actual manufacturing, the thickness of each material has fluctuation, thus the thickness and thickness sum in the embodiment of the present application has a floating range of plus or minus 20%.

[0186] Due to the fact that the ultrasonic penetration is more sensitive to the thickness of the glass, thus the thickness of the glass is designed to have a floating range of plus or minus 10%.

[0187] Another embodiment of the present application further provides an electronic device, which comprises a screen with an under-screen ultrasonic fingerprint identification function and any one of the screen protection films or the mixed hardening adhesive layer and the glass layer attached by the mixed hardening adhesive layer. The specific implementation of the embodiment of the present application is further described below in combination with the drawings of the embodiment of the present application.

[0188] Referring to FIG. 11, the embodiment of the present application provides a screen protection film applied to a screen with an under-screen ultrasonic fingerprint identification function. The screen protection film comprises a glass layer and a mixed hardening adhesive layer, and the mixed hardening adhesive layer is used to attach the glass layer to the surface of the screen.

[0189] Specifically, one side of the mixed hardening adhesive layer is used to set a release film, or both sides of the mixed hardening adhesive layer are used to set a release film.

[0190] When one side of the mixed hardening adhesive layer is used to set a release film, the other side of the mixed hardening adhesive layer is directly attached to the glass layer. When the release film is peeled off from one side of the mixed hardening adhesive layer, the mixed hardening adhesive layer attaches the glass layer to the surface of the screen. At the time of attachment, the optical adhesive layer is attached to the glass layer, and the silica gel layer is attached to the screen.

[0191] When both sides of the mixed hardening adhesive layer are used to set a release film, when the release film is peeled off from one side of the mixed hardening adhesive layer, one side of the mixed hardening adhesive layer is attached to the surface of the screen; when the release film is peeled off from the other side of the mixed hardening adhesive layer, the other side of the mixed hardening adhesive layer is attached to the surface of the glass.

[0192] The mixed hardening adhesive layer comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence.

[0193] The propagation time of ultrasonic waves in the mixed hardening adhesive layer is equal to or the sum of the propagation time of ultrasonic waves in the optical adhesive layer and the substrate layer is equal to or the sum of the propagation time of ultrasonic waves in the substrate layer and the silica gel layer is equal to wherein N is a positive integer, and T0 is the period of the ultrasonic wave. Wherein D OCA is the thickness of the optical adhesive layer, u OCA is the wave velocity of the longitudinal wave of the ultrasonic wave in the optical adhesive layer, D PETis the thickness of the substrate layer, u PET is the wave velocity of the longitudinal wave of the ultrasonic wave propagating in the substrate layer, D SL is the thickness of the silica gel layer, u SL is the wave velocity of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer.

[0194] From the above analysis, the propagation time of the ultrasonic wave in the mixed hardening glue layer is equal to The ultrasonic wave penetration rate is relatively high.

[0195] If the propagation time of the ultrasonic wave in the mixed hardening glue layer cannot satisfy The sum of the propagation time of the ultrasonic wave in the optical glue layer and the substrate layer or the substrate layer and the silica gel layer is equal to

[0196] Specifically, if the frequency of the ultrasonic wave is 11MHz; the propagation time of the ultrasonic wave in the mixed hardening glue layer is equal to The material of the silica gel layer has a greater influence on the penetration rate of the ultrasonic wave, that is, the penetration rate of the ultrasonic wave is more sensitive to the material of the silica gel layer, so the thickness of the silica gel layer is set to be thinner than the optical glue layer and the substrate layer, thereby reducing the attenuation of the ultrasonic wave energy. For example, the thickness of the optical glue layer is 30um; the thickness of the substrate layer is 25um; and the thickness of the silica gel layer is 20um. In this example, the propagation time of the ultrasonic wave in the mixed hardening glue layer is equal to 30 / 1.8+25 / 2.4+20 / 1.2=43.75ns, and the period is 90.9ns, that is, in this scheme, N can be equal to 1.

[0197] In some specific implementations of the embodiments of the present application, the thickness of the silica gel layer is less than the thickness of the optical glue layer; the thickness of the silica gel layer is less than the thickness of the substrate layer. Thus, the influence of the tempered protective film on the ultrasonic under-screen fingerprint identification is further improved, and the fingerprint identification is better achieved.

[0198] In the scheme of the embodiments of the present application, the screen protective film includes a glass layer and a mixed hardening glue layer, the glass layer is attached to the surface of the screen through the mixed hardening glue layer, and the mixed hardening glue layer includes an optical glue layer, a substrate layer and a silica gel layer arranged in sequence. The thickness of the optical glue layer, the substrate layer and the silica gel layer is set in the embodiments of the present application, thereby improving the influence of the tempered protective film on the ultrasonic under-screen fingerprint identification, and better achieving the fingerprint identification.

[0199] The embodiments of the present application also provide a mixed hardening glue layer, the mixed hardening glue layer includes an optical glue layer, a substrate layer and a silica gel layer arranged in sequence, and the propagation time of the ultrasonic wave in the mixed hardening glue layer is equal to Or; the sum of the propagation time of the ultrasonic wave in the optical glue layer and the substrate layer is equal to Or; the sum of the propagation time of the ultrasonic wave in the substrate layer and the silica gel layer is equal to Wherein, N is a positive integer, and T0 is a period of the ultrasonic wave; the two sides of the mixed hardening adhesive layer are respectively provided with an upper release film and a lower release film.

[0200] When one side of the mixed hardening adhesive layer is used to set the release film, the other side of the mixed hardening adhesive layer is directly attached to the glass layer; when the release film is peeled off from one side of the mixed hardening adhesive layer, the mixed hardening adhesive layer attaches the glass layer to the surface of the screen.

[0201] When both sides of the mixed hardening adhesive layer are used to set the release film, when the release film is peeled off from one side of the mixed hardening adhesive layer, one side of the mixed hardening adhesive layer is attached to the surface of the screen; when the release film is peeled off from the other side of the mixed hardening adhesive layer, the other side of the mixed hardening adhesive layer is attached to the surface of the glass.

[0202] The embodiment of the present application also provides a mixed hardening adhesive layer, which comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence, the thickness of the optical adhesive layer is equal to λ2 / 2*M or less than λ2 / 8, the thickness of the substrate layer is equal to λ4 / 2*M or less than λ4 / 8, and the thickness of the silica gel layer is equal to λ1 / 2*M or less than λ1 / 8, wherein M is a positive integer, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer, and λ4 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the substrate layer.

[0203] When one side of the mixed hardening adhesive layer is used to set the release film, the other side of the mixed hardening adhesive layer is directly attached to the glass layer; when the release film is peeled off from one side of the mixed hardening adhesive layer, the mixed hardening adhesive layer attaches the glass layer to the surface of the screen.

[0204] When both sides of the mixed hardening adhesive layer are used to set the release film, when the release film is peeled off from one side of the mixed hardening adhesive layer, one side of the mixed hardening adhesive layer is attached to the surface of the screen; when the release film is peeled off from the other side of the mixed hardening adhesive layer, the other side of the mixed hardening adhesive layer is attached to the surface of the glass.

[0205] In some specific implementations of the embodiment of the present application, if the sum of the propagation time of the ultrasonic wave in the optical adhesive layer and the substrate layer is equal to then the thickness of the silica gel layer is equal to λ1 / 2*M or less than λ1 / 8.

[0206] Specifically, if the frequency of the ultrasonic wave is 11MHz, the thickness of the optical adhesive layer is 55um, the thickness of the substrate layer is 30um, and the thickness of the silica gel layer is 55um, in this example, the sum of the propagation time of the ultrasonic wave in the optical adhesive layer and the substrate layer is equal to 55 / 1.8+30 / 2.4=43ns, and the period is 90.9ns, that is, in this scheme, N can be equal to 1, and the half of the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer is about 54.5 microns, that is, in this scheme, M can be equal to 1.

[0207] Or, if the sum of the propagation time of the ultrasonic wave in the substrate layer and the silica gel layer is equal to The thickness of the optical adhesive layer is equal to λ2 / 2*M, or less than λ2 / 8; wherein M is a positive integer, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, and λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer.

[0208] Specifically, if the frequency of the ultrasonic wave is 11MHz; the thickness of the optical adhesive layer is 75um; the thickness of the substrate layer is 20um; and the thickness of the silica gel layer is 45um, in this example, the sum of the propagation time of the ultrasonic wave in the substrate layer and the silica gel layer is equal to 45 / 1.2+20 / 2.4=45.8ns, and the period is 90.9ns, that is, in this scheme, N can be equal to 1, and the half of the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer is about 81.81 microns, that is, in this scheme, M can be equal to 1, and the error of the thickness of the optical adhesive layer is, for example, plus or minus 8.32%. In this embodiment, if the thickness error of the optical adhesive layer, the silica gel layer and the substrate layer is controlled within 10%, the attenuation of the ultrasonic wave is less, and the fingerprint recognition effect can be further improved.

[0209] The embodiments of the present application further set the thickness of the optical adhesive layer, the substrate layer and the silica gel layer, so as to better improve the influence of the tempered protective film on the ultrasonic wave under-screen fingerprint recognition, and improve the effect of fingerprint recognition.

[0210] At present, the application frequency of ultrasonic wave under-screen fingerprint is generally 10-13MHz, considering the process technology of the glass layer, the thickness of the glass layer is set to λ3 / 2, and λ3 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the glass.

[0211] Specifically, the thickness of the glass layer is 250um.

[0212] Referring to FIG. 11, the embodiments of the present application provide a screen protective film applied to a screen with under-screen ultrasonic wave fingerprint recognition function. The screen protective film comprises: a glass layer and a mixed hardening adhesive layer, and the glass layer is attached to the surface of the screen through the mixed hardening adhesive layer.

[0213] Specifically, one side of the mixed hardening adhesive layer is used to set a release film, or both sides of the mixed hardening adhesive layer are used to set a release film.

[0214] When one side of the mixed hardening adhesive layer is used to set a release film, and the other side is attached to the glass layer, when the release film is peeled off from one side of the mixed hardening adhesive layer, the mixed hardening adhesive layer is used to attach the glass layer to the surface of the screen.

[0215] When the two sides of the mixed hardening adhesive layer are used to set the release film, when the release film is peeled off from one side of the mixed hardening adhesive layer, the one side of the mixed hardening adhesive layer is attached to the surface of the glass layer; when the release film is peeled off from the other side of the mixed hardening adhesive layer, the other side of the mixed hardening adhesive layer is attached to the surface of the screen.

[0216] The mixed hardening adhesive layer comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence, the thickness of the optical adhesive layer is equal to λ2 / 2*O or less than λ2 / 8, the thickness of the substrate layer is equal to λ4 / 2*P or less than λ4 / 8, and the thickness of the silica gel layer is equal to λ1 / 2*Q or less than λ1 / 8, wherein M is a positive integer, λ1 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer, λ2 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer, and λ4 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the substrate layer.

[0217] In the scheme of the embodiment of the present application, the screen protection film comprises a glass layer and a mixed hardening adhesive layer, the glass layer is attached to the surface of the screen through the mixed hardening adhesive layer, and the mixed hardening adhesive layer comprises an optical adhesive layer, a substrate layer and a silica gel layer arranged in sequence. The thicknesses of the optical adhesive layer, the substrate layer and the silica gel layer are set in the embodiment of the present application, so that the influence of the tempered protection film on the ultrasonic screen under fingerprint recognition is improved, and the fingerprint recognition is better achieved.

[0218] Specifically, if the frequency of the ultrasonic wave is 11 MHz, the thickness of the optical adhesive layer is 75 um, the thickness of the substrate layer is 20 um, and the thickness of the silica gel layer is 55 um, in this example, half of the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silica gel layer is about 54.5 microns, that is, in the scheme, Q can be equal to 1; half of the wavelength of the longitudinal wave of the ultrasonic wave propagating in the optical adhesive layer is about 81.81 microns, that is, in the scheme, O can be equal to 1, and the error of the thickness of the optical adhesive layer is, for example, plus or minus 8.32%; λ4 / 8 is about 27.27 microns, that is, in the scheme, the thickness of the substrate layer 20 um is less than λ4 / 8.

[0219] At present, the application frequency of the ultrasonic screen under fingerprint is generally 10-13 MHz, and considering the process technology of the glass layer, the thickness of the glass layer is set to λ3 / 2, and λ3 is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the glass.

[0220] Specifically, the thickness of the glass layer is 250 um.

[0221] Due to the process requirements of actual manufacturing, the thicknesses of various materials have fluctuations, and therefore, the floating range of the propagation time and the thickness in the embodiment of the present application is plus or minus 20%.

[0222] Since the ultrasonic wave penetration rate is more sensitive to the thickness of the glass, the thickness of the glass is designed to have a floating range of plus or minus 10%.

[0223] Another embodiment of the present application also provides an electronic device, which comprises a screen with an under-screen ultrasonic fingerprint identification function and any one of the screen protection films or the mixed hardening adhesive layer and the glass layer attached by the mixed hardening adhesive layer. The specific implementation of the embodiments of the present application is further described below in combination with the drawings of the embodiments of the present application.

[0224] The specific implementation of the embodiments of the present application is further described below in combination with the drawings of the embodiments of the present application.

[0225] The electronic device of the embodiments of the present application includes but is not limited to:

[0226] (1) Mobile communication device: the feature of this kind of device is to have mobile communication function and to provide voice and data communication as the main target. This kind of terminal includes smart phone, multimedia phone, functional phone, and low-end phone, etc.

[0227] (2) Ultra-mobile personal computer device: this kind of device belongs to the category of personal computer and has computing and processing functions, and generally has the feature of mobile Internet. This kind of terminal includes PAD, MID, UMPC device, etc.

[0228] (3) Portable entertainment device: this kind of device can display and play multimedia content. This kind of device includes audio and video player, handheld game console, electronic book, smart toy, and portable car navigation device.

[0229] (4) Door lock, car lock, and other electronic devices with data interaction function.

[0230] The above-mentioned embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

A hybrid curing adhesive layer is used to attach a glass layer to the outer screen of an electronic device with under-display ultrasonic fingerprint recognition functionality; wherein... The hybrid curing adhesive layer includes N first adhesive layers, a substrate layer, and M second adhesive layers arranged sequentially. The first first adhesive layer is used to attach to the glass layer, and the last second adhesive layer is used to attach to the outer screen of the screen. N is a positive integer, and M is a positive integer. The thickness of at least one structural layer of the mixed hardening adhesive layer satisfies the following thickness condition: if the acoustic impedance of the (i-1)th structural layer is the same as that of the (i+1)th structural layer, then the thickness of the i-th structural layer is... If the acoustic impedance of the (i-1)th structural layer is different from that of the (i+1)th structural layer, and the acoustic impedance of the ith structural layer falls between the acoustic impedances of the (i-1)th and (i+1)th structural layers, then the thickness of the ith structural layer is: If the acoustic impedance of the (i-1)th structural layer is different from that of the (i+1)th structural layer, and the acoustic impedance of the ith structural layer is not between that of the (i-1)th and (i+1)th structural layers, then the thickness of the ith structural layer is: Wherein, the i-th structural layer is any one of the N first adhesive layers, the substrate layer, and the M second adhesive layers; λi is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the i-th structural layer, k is a positive integer, 2≤i≤(N+M+1). According to claim 1, the mixed hardening adhesive layer, wherein, The thickness of at least two structural layers of the mixed hardening adhesive layer satisfies the thickness condition, the first i-1th structural layer is the glass layer, and the last i+1th layer is the outer screen of the screen. According to claim 1, the mixed hardening adhesive layer, wherein, The mixed curing adhesive layer includes a first adhesive layer, a substrate layer and a second adhesive layer arranged sequentially. The first adhesive layer is a UV adhesive layer, the substrate layer is a PET layer and the second adhesive layer is a silicone layer. The thickness of the UV adhesive layer is λ UV The wavelength of the longitudinal wave of the ultrasound propagating in the UV adhesive layer is ; the thickness of the PET layer is . λ PET The wavelength of the longitudinal wave of the ultrasound propagating in the PET layer is ; the thickness of the silicone layer is . λ 硅胶 λ is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the silicone layer; where O, P, and Q are positive integers. According to claim 3, the mixed hardening adhesive layer, wherein, O is 1 or 2, P is 1 or 2, and Q is 1. According to claim 3, the mixed hardening adhesive layer, wherein, If the frequency of the ultrasonic wave is 12MHz, the thickness of the UV adhesive layer is 54um-66um or 162um-198um, the thickness of the PET layer is 45um-55um or 135um-165um, and the thickness of the silicone layer is 45um-55um; or... If the frequency of the ultrasonic wave is 11MHz, the thickness of the UV adhesive layer is 59um-72um or 176um-215um, the thickness of the PET layer is 51um-61um or 149um-182um, and the thickness of the silicone layer is 49um-59um; or... If the frequency of the ultrasonic wave is 10MHz, the thickness of the UV adhesive layer is 65um-79um or 194um-238um, the thickness of the PET layer is 54um-66um or 162um-198um, and the thickness of the silicone layer is 54um-66um. According to claim 5, the mixed hardening adhesive layer, wherein, If the frequency of the ultrasonic wave is 12MHz, the thickness of the UV adhesive layer is 60µm or 180µm, the thickness of the PET layer is 50µm or 150µm, and the thickness of the silicone layer is 50µm; or... If the frequency of the ultrasonic wave is 11MHz, the thickness of the UV adhesive layer is 65µm or 195µm, the thickness of the PET layer is 55µm or 165µm, and the thickness of the silicone layer is 54µm; or... If the frequency of the ultrasonic wave is 10MHz, the thickness of the UV adhesive layer is 72um or 216um, the thickness of the PET layer is 60um or 180um, and the thickness of the silicone layer is 60um. According to claim 1, the mixed hardening adhesive layer, wherein, The thickness of at least three structural layers of the mixed curing adhesive layer satisfies the thickness condition. The mixed curing adhesive layer includes two first adhesive layers, a substrate layer and one second adhesive layer arranged in sequence. The two first adhesive layers are a silicone layer and an OCA adhesive layer arranged in sequence. The substrate layer is a PET layer and the second adhesive layer is a UV adhesive layer. The thickness of the silicone layer is λ 硅胶 The wavelength of the longitudinal wave of the ultrasound propagating in the silicone layer is ; the thickness of the OCA adhesive layer is . λ OCA The wavelength of the longitudinal wave of the ultrasound propagating in the OCA adhesive layer is ; the thickness of the PET layer is . λ PET The wavelength of the longitudinal wave of the ultrasound propagating in the PET layer is ; the thickness of the UV adhesive layer is . λ UV is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the UV adhesive layer; where O, P, Q and R are positive integers. According to claim 7, the mixed hardening adhesive layer, wherein, O is 1 or 2, P is 1 or 2, Q is 1, and R is 1 or 2. According to claim 8, the mixed hardening adhesive layer, wherein, If the frequency of the ultrasonic wave is 12MHz, the thickness of the silicone layer is 45um-55um or 90um-110um, the thickness of the OCA adhesive is 34um-42um or 104um-127um, the thickness of the PET layer is 45um-55um, and the thickness of the UV adhesive layer is 54um-66um or 162um-198um; or... If the frequency of the ultrasonic wave is 11MHz, the thickness of the silicone layer is 50um-61um or 99um-121um, the thickness of the OCA adhesive layer is 37um-45um or 113um-138um, the thickness of the PET layer is 50um-61um, and the thickness of the UV adhesive layer is 59um-72um or 177um-217um; or... If the frequency of the ultrasonic wave is 10MHz, the thickness of the silicone layer is 54um-66um or 108um-132um, the thickness of the OCA adhesive layer is 41um-51um or 124um-152um, the thickness of the PET layer is 54um-66um, and the thickness of the UV adhesive is 65um-79um or 194um-237um. According to claim 9, the mixed hardening adhesive layer, wherein, If the frequency of the ultrasonic wave is 12MHz, the thickness of the silicone layer is 50um or 100um, the thickness of the OCA adhesive is 38um or 115um, the thickness of the PET layer is 50um, and the thickness of the UV adhesive layer is 60um or 180um. or, If the frequency of the ultrasonic wave is 11MHz, the thickness of the silicone layer is 55um or 110um, the thickness of the OCA adhesive layer is 41um or 125um, the thickness of the PET layer is 55um, and the thickness of the UV adhesive layer is 65um or 197um. or, If the frequency of the ultrasonic wave is 10MHz, the thickness of the silicone layer is 60um or 120um, the thickness of the OCA adhesive layer is 46um or 138um, the thickness of the PET layer is 60um, and the thickness of the UV adhesive is 72um or 215um. According to claim 1, the mixed hardening adhesive layer, wherein, The thickness of at least three structural layers of the mixed curing adhesive layer satisfies the thickness condition. The mixed curing adhesive layer includes two first adhesive layers, a substrate layer and one second adhesive layer arranged in sequence. The two first adhesive layers are a UV adhesive layer and an OCA adhesive layer arranged in sequence. The substrate layer is a PET layer and the second adhesive layer is a silicone layer. The thickness of the UV adhesive layer is λ UV The wavelength of the longitudinal wave of the ultrasonic wave propagating in the UV adhesive layer is ; the thickness of the OCA adhesive layer is . λ OCA The wavelength at which the ultrasonic wave propagates in the OCA adhesive layer is; the thickness of the PET layer is... λ PET The wavelength at which the ultrasonic wave propagates in the PET layer is; the thickness of the silicone layer is... λ UV is the wavelength of the ultrasonic wave propagating in the silicone layer; where O, P, Q, and R are positive integers. The mixed hardening adhesive layer according to any one of claims 1 to 11, wherein, A release film is provided on each side of the mixed hardening adhesive layer. A screen protector is used to attach to the outer screen of an electronic device that has an under-display ultrasonic fingerprint recognition function. The screen protector comprises a glass layer and a hybrid hardening adhesive layer as described in any one of claims 1-11: The first adhesive layer of the mixed-curing adhesive layer is attached to the glass layer, and the last adhesive layer of the mixed-curing adhesive layer is attached to the outer screen of the screen; the thickness of the glass layer is... Where, λ 玻璃 S is the wavelength of the longitudinal wave of the ultrasonic wave propagating in the glass layer, and S is a positive integer. According to claim 13, the screen protector film, wherein, If the frequency of the ultrasonic wave is 12MHz, the thickness of the glass layer is 221um-270um; or, if the frequency of the ultrasonic wave is 11MHz, the thickness of the glass layer is 243um-297um; or, if the frequency of the ultrasonic wave is 10MHz, the thickness of the glass layer is 261um-319um. According to claim 14, the screen protector film, wherein, If the frequency of the ultrasonic wave is 12MHz, the thickness of the glass layer is 245µm; or, if the frequency of the ultrasonic wave is 11MHz, the thickness of the glass layer is 270µm; or, if the frequency of the ultrasonic wave is 10MHz, the thickness of the glass layer is 290µm. According to claim 13, the screen protector film, wherein, A release film is provided on the last second adhesive layer of the mixed hardening adhesive layer. An electronic device includes a screen protector as described in any one of claims 13-16 and the screen, wherein the screen protector is attached to an outer screen of the screen.

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