Fingerprint identification module
By introducing a thermal stress buffer layer between the glass substrate and the anti-fingerprint layer, the problem of interfacial thermal stress caused by the difference in thermal expansion coefficients is solved, the adhesion stability of the anti-fingerprint layer is improved, and the risk of peeling off under high temperature conditions is reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TRULY OPTO-ELECTRONICS TECH LTD
- Filing Date
- 2025-04-18
- Publication Date
- 2026-04-17
AI Technical Summary
In high-temperature environments, the difference in thermal expansion coefficients between the protective cover and the anti-fingerprint layer is significant, resulting in high interfacial thermal stress, which affects the adhesion of the anti-fingerprint layer and makes it prone to peeling off.
A thermal stress buffer layer with a thermal expansion coefficient between the glass substrate and the anti-fingerprint layer is introduced to decompose the interfacial thermal stress, reduce the interfacial thermal stress, and improve the adhesion stability.
By decomposing thermal stress, the risk of the anti-fingerprint layer peeling off in high-temperature environments is reduced, and the adhesion stability is improved.
Smart Images
Figure CN224137745U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to fingerprint recognition technology, and more particularly to a fingerprint recognition module. Background Technology
[0002] A fingerprint recognition module is a device that collects, processes, and identifies human fingerprints, primarily used for identity authentication or information security management based on human fingerprint characteristics.
[0003] Because fingerprint recognition modules come into frequent contact with fingers, an anti-fingerprint layer is installed on the protective cover to prevent fingerprint oil from remaining on the cover. However, the protective cover is made of glass, which is an inorganic material, while the anti-fingerprint layer is made of fluoropolymer, which is an organic material. The difference in their coefficients of thermal expansion is significant. Under high temperature conditions, the interfacial thermal stress between the protective cover and the anti-fingerprint layer is large, which reduces the adhesion of the anti-fingerprint layer to the protective cover and makes it easy to fall off, thus affecting the anti-fingerprint function of the product. Utility Model Content
[0004] To address the shortcomings of the prior art, this invention provides a fingerprint recognition module that can improve the adhesion stability of the anti-fingerprint layer on a glass substrate.
[0005] The technical problem to be solved by this utility model is achieved through the following technical solution:
[0006] A fingerprint recognition module includes a protective cover and a fingerprint sensor, wherein the protective cover is disposed on the sensing side of the fingerprint sensor; the protective cover includes:
[0007] Glass substrate;
[0008] A thermal stress buffer layer is disposed on the side of the glass substrate away from the fingerprint sensor;
[0009] An anti-fingerprint layer is disposed on the side of the thermal stress buffer layer away from the glass substrate;
[0010] The coefficient of thermal expansion of the thermal stress buffer layer is between that of the glass substrate and the anti-fingerprint layer.
[0011] Furthermore, the ratio of the coefficient of thermal expansion between the thermal stress buffer layer and the glass substrate, and between the thermal stress buffer layer and the anti-fingerprint layer, is ≤3.
[0012] Furthermore, the anti-fingerprint layer is a fluoropolymer.
[0013] Furthermore, the thickness of the anti-fingerprint layer is 5-50 nm.
[0014] Furthermore, the thermal stress buffer layer is a siloxane resin, an acrylate resin, or a polyurethane resin.
[0015] Furthermore, the thickness of the thermal stress buffer layer is greater than that of the anti-fingerprint layer.
[0016] Furthermore, the thickness ratio between the thermal stress buffer layer and the anti-fingerprint layer is ≤10.
[0017] Furthermore, the thickness of the thermal stress buffer layer is 100-300 nm.
[0018] Furthermore, the glass substrate is aluminosilicate glass or sodium-calcium silicate glass.
[0019] Furthermore, the fingerprint sensor is a capacitive sensor, an optical sensor, or an ultrasonic sensor.
[0020] This invention has the following beneficial effects: The fingerprint recognition module of this invention adds a thermal stress buffer layer between the glass substrate and the anti-fingerprint layer of the protective cover plate, so as to decompose the thermal stress between the glass substrate and the anti-fingerprint layer into the interfacial thermal stress between the glass substrate and the thermal stress buffer layer, and the interfacial thermal stress between the thermal stress buffer layer and the anti-fingerprint layer. Since the thermal expansion coefficient of the thermal stress buffer layer is between that of the glass substrate and the anti-fingerprint layer, the two interfacial thermal stresses after decomposition are both less than the thermal stress between the glass substrate and the anti-fingerprint layer, thereby improving the adhesion stability of the anti-fingerprint layer on the glass substrate and reducing the risk of the anti-fingerprint layer falling off in a high-temperature environment. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the stacked structure of the fingerprint recognition module provided by this utility model. Detailed Implementation
[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, examples of which are shown in the drawings. Throughout the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0023] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0024] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.
[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," "fixing," and "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0026] Example 1
[0027] like Figure 1 As shown, a fingerprint recognition module includes a protective cover 1 and a fingerprint sensor 2, wherein the protective cover 1 is disposed on the sensing side of the fingerprint sensor; the protective cover 1 includes:
[0028] Glass substrate 11;
[0029] A thermal stress buffer layer 12 is disposed on the side of the glass substrate 11 away from the fingerprint sensor 2;
[0030] Anti-fingerprint layer 13, wherein the anti-fingerprint layer 13 is disposed on the side of the thermal stress buffer layer 12 away from the glass substrate 11;
[0031] The coefficient of thermal expansion of the thermal stress buffer layer 12 is between that of the glass substrate 11 and the anti-fingerprint layer 13.
[0032] The fingerprint recognition module of this invention adds a thermal stress buffer layer 12 between the glass substrate 11 and the anti-fingerprint layer 13 of the protective cover plate 1. This decomposes the thermal stress between the glass substrate 11 and the anti-fingerprint layer 13 into interfacial thermal stress between the glass substrate 11 and the thermal stress buffer layer 12, and interfacial thermal stress between the thermal stress buffer layer 12 and the anti-fingerprint layer 13. Since the thermal expansion coefficient of the thermal stress buffer layer 12 is between that of the glass substrate 11 and the anti-fingerprint layer 13, the two interfacial thermal stresses after decomposition are both less than the thermal stress between the glass substrate 11 and the anti-fingerprint layer 13. This improves the adhesion stability of the anti-fingerprint layer 13 on the glass substrate 11 and reduces the risk of the anti-fingerprint layer 13 falling off in high-temperature environments.
[0033] In this embodiment, the fingerprint sensor 2 is a capacitive sensor, an optical sensor, or an ultrasonic sensor. It can be directly bonded and fixed to the protective cover plate 1 with OCA optical adhesive, or it can be assembled with the protective cover plate 1 in the same terminal housing so that the relative position between the two can be fixed by the terminal housing.
[0034] Preferably, the ratio of the coefficients of thermal expansion between the thermal stress buffer layer 12 and the glass substrate 11, and between the thermal stress buffer layer 12 and the anti-fingerprint layer 13, is ≤3. Assuming the coefficient of thermal expansion of the glass substrate 11 is CTE1, the coefficient of thermal expansion of the thermal stress buffer layer 12 is CTE2, and the coefficient of thermal expansion of the anti-fingerprint layer 13 is CTE3, then CTE2 / CTE1 ≤ 3, and CTE3 / CTE2 ≤ 3.
[0035] When the ratio of the coefficient of thermal expansion between the thermal stress buffer layer 12 and the glass substrate 11, and the ratio of the coefficient of thermal expansion between the thermal stress buffer layer 12 and the anti-fingerprint layer 13 are both controlled within 3, the interfacial thermal stress of the glass substrate 11, the thermal stress buffer layer 12 and the anti-fingerprint layer 13 under the normal temperature difference range (such as -20°C to 60°C, ΔT=80°C) can meet the interfacial bonding strength or allowable material stress, which can significantly reduce the risk of failure while taking cost into consideration.
[0036] In this embodiment, the anti-fingerprint layer 13 is a commonly used fluoropolymer (CTE=(80–150)×10). -6 / K), the glass substrate 11 is a commonly used aluminosilicate glass (CTE=(7.0–8.5)×10). -6 / K) or soda-lime silicate glass (CTE=(8.5–9.0)×10 -6 / K).
[0037] The thermal stress buffer layer 12 can be made of silicone resin (CTE=(20–50)×10).-6 / K), acrylate resin (CTE=(40–80)×10 -6 / K) or polyurethane resin (CTE=(50–100)×10 -6 (e.g., / K)
[0038] Preferably, the thermal stress buffer layer 12 may be doped with inorganic fillers such as silicon oxide, aluminum oxide, or silicon oxide, so as to adjust the thermal expansion coefficient of the thermal stress buffer layer 12 by the mass ratio of the inorganic fillers, thereby achieving optimal CTE matching.
[0039] In this embodiment, the thermal stress buffer layer 12 is a siloxane resin, such as methyltrimethoxysilane, γ-aminopropyltriethoxysilane, or γ-glycidoxypropyltrimethoxysilane. The siloxane resin not only decomposes the thermal stress between the glass substrate 11 and the anti-fingerprint layer 13 through a matching mechanism of thermal expansion coefficients, but its alkoxy groups (-OCH3) can also form Si-O-Si covalent bonds with the hydroxyl groups (-OH) of the glass substrate 11. Furthermore, its organic groups (such as amino, methyl, ethyl, or epoxy groups) can bond with the anti-fingerprint layer 13 through van der Waals forces or hydrogen bonds, thereby further enhancing the interfacial bonding strength.
[0040] Preferably, the thickness of the thermal stress buffer layer 12 is greater than that of the anti-fingerprint layer 13, and the thickness ratio between the thermal stress buffer layer 12 and the anti-fingerprint layer 13 is ≤10, so that the thermal stress buffer layer 12 can provide sufficient mechanical buffer space for the anti-fingerprint layer 13, allowing the anti-fingerprint layer 13 to achieve its surface anti-fingerprint function with an ultra-thin thickness, while avoiding stress concentration caused by abrupt change in interface modulus between the two.
[0041] In this embodiment, the thickness of the anti-fingerprint layer 13 is 5-50nm, and the thickness of the thermal stress buffer layer 12 is 100-300nm.
[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and not to limit them. Although the present utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present utility model, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the present utility model.
Claims
1. A fingerprint recognition module, comprising a protective cover and a fingerprint sensor, wherein the protective cover is disposed on the sensing side of the fingerprint sensor; characterized in that, The protective cover includes: Glass substrate; A thermal stress buffer layer is disposed on the side of the glass substrate away from the fingerprint sensor; An anti-fingerprint layer is disposed on the side of the thermal stress buffer layer away from the glass substrate; The coefficient of thermal expansion of the thermal stress buffer layer is between that of the glass substrate and the anti-fingerprint layer.
2. The fingerprint identification module according to claim 1, wherein, The ratio of the coefficient of thermal expansion between the thermal stress buffer layer and the glass substrate, and between the thermal stress buffer layer and the anti-fingerprint layer, is ≤3.
3. The fingerprint identification module of claim 1, wherein, The anti-fingerprint layer is a fluoropolymer.
4. The fingerprint identification module according to claim 1 or 3, characterized in that, The thermal stress buffer layer is made of siloxane resin, acrylate resin, or polyurethane resin.
5. The fingerprint identification module of claim 1, wherein, The thickness of the thermal stress buffer layer is greater than that of the anti-fingerprint layer.
6. The fingerprint identification module according to claim 1 or 5, characterized in that, The thickness ratio between the thermal stress buffer layer and the anti-fingerprint layer is ≤10.
7. The fingerprint identification module of claim 1, wherein, The thickness of the anti-fingerprint layer is 5-50nm. 8.The fingerprint identification module according to claim 1 or 7, characterized in that, The thickness of the thermal stress buffer layer is 100-300 nm.
9. The fingerprint identification module of claim 1, wherein, The glass substrate is aluminosilicate glass or sodium-calcium silicate glass.
10. The fingerprint identification module of claim 1, wherein, The fingerprint sensor is a capacitive sensor, an optical sensor, or an ultrasonic sensor.