Sensor assembly and electronic device

Abstract

This application discloses a sensor assembly, including an insulating substrate comprising a first surface and a second surface disposed opposite to each other; a surface acoustic wave (SAW) pressure sensor disposed on the first surface, the SAW pressure sensor comprising a piezoelectric lithium niobate layer and two pairs of interdigital transducers disposed on the surface of the piezoelectric lithium niobate layer, the piezoelectric lithium niobate layer having a cavity and a corresponding thinned sensitive membrane region, the two pairs of interdigital transducers being disposed around the thinned sensitive membrane region in mutually perpendicular directions; and a platinum resistance temperature sensor and an interdigital capacitance humidity sensor disposed on the second surface. By having the SAW pressure sensor, platinum resistance temperature sensor, and interdigital capacitance humidity sensor disposed opposite to each other on the insulating substrate, combined with the cavity formed on the piezoelectric lithium niobate layer, and the two pairs of interdigital transducers disposed in mutually perpendicular directions, the detection accuracy is improved and crosstalk is reduced.

Description

Technical Field

[0001] This application belongs to the field of sensor equipment technology, specifically relating to a sensor component and electronic device. Background Technology

[0002] Temperature, pressure, and humidity are three important parameters in environmental monitoring. In related technologies, environmental monitoring systems typically employ a combination of multiple discrete sensors, resulting in large size, high power consumption, and complex circuit packaging, making it difficult to meet the demands for miniaturization and integration. Furthermore, in the exploration of technologies to miniaturize sensors, it is often difficult to simultaneously achieve miniaturization, high accuracy, and environmental adaptability. Summary of the Invention

[0003] This application provides a sensor assembly and electronic device that aims to achieve miniaturization of multi-parameter sensors while improving detection accuracy and environmental adaptability.

[0004] To achieve the above objectives, the sensor assembly provided in this application includes: An insulating base layer, comprising a first surface and a second surface disposed opposite to each other; A surface acoustic wave (SAW) pressure sensor is disposed on the first surface. The SAW pressure sensor includes a piezoelectric lithium niobate layer and two pairs of interdigital transducers disposed on the surface of the piezoelectric lithium niobate layer. A cavity is formed within the piezoelectric lithium niobate layer, and a thinned sensitive diaphragm region corresponding to the cavity is formed therein. The two pairs of interdigital transducers are arranged around the thinned sensitive diaphragm region in mutually perpendicular directions. A platinum resistance temperature sensor and an interdigital capacitive humidity sensor are mounted on the second surface.

[0005] In some implementations, the insulating base layer is a silicon dioxide layer.

[0006] In some implementations, the platinum resistance temperature sensor includes a temperature sensor electrode and a thermistor.

[0007] In some embodiments, the interdigital capacitive humidity sensor includes interdigital electrodes and a humidity-sensitive medium filled between the interdigital electrodes.

[0008] In some implementations, the longitudinal direction of the platinum resistance temperature sensor and the longitudinal direction of the interdigital capacitive humidity sensor are parallel to each other.

[0009] In some embodiments, the two pairs of interdigital transducers include a first interdigital transducer pair and a second interdigital transducer pair. The first interdigital transducer pair includes two opposing first interdigital transducers, and the second interdigital transducer pair includes two opposing second interdigital transducers. The first interdigital transducer pair is arranged along a third direction, and the second interdigital transducer pair is arranged along a fourth direction, which is perpendicular to the fourth direction.

[0010] In some implementations, a platinum resistance temperature sensor and an interdigital capacitive humidity sensor are positioned corresponding to the cavity.

[0011] In some implementations, the cavity has a trapezoidal cross-section along a third or fourth direction.

[0012] In some embodiments, two pairs of interdigital transducers are arranged around the thinning-sensitive membrane region, and at least a portion of the two pairs of interdigital transducers are located above the thinning-sensitive membrane region.

[0013] This application also provides an electronic device, which includes the aforementioned sensor assembly.

[0014] In the sensor assembly provided in this application, the platinum resistance temperature sensor and the interdigital capacitive humidity sensor have high detection accuracy and environmental adaptability. By integrating the surface acoustic wave pressure sensor, the platinum resistance temperature sensor, and the interdigital capacitive humidity sensor onto a first surface and a second surface disposed opposite to each other on an insulating substrate, crosstalk between the platinum resistance temperature sensor and the interdigital capacitive humidity sensor on the surface acoustic wave pressure sensor signal is reduced. By forming a cavity on a piezoelectric lithium niobate layer and attaching one side of the piezoelectric lithium niobate layer to the first surface, thereby covering the cavity with an insulating substrate to form a blind cavity structure, the stability and detection accuracy of the blind cavity structure can be further improved. By arranging two pairs of interdigital transducers arranged in mutually perpendicular directions around the thinned sensitive diaphragm area and using the mutual adjustment of the signals between the two pairs of interdigital transducers, the influence of the force angle can be further reduced on the basis of the highly sensitive blind cavity structure, further improving the detection accuracy. At the same time, since the platinum resistance temperature sensor and the surface acoustic wave pressure sensor 200 are disposed on different surfaces, they can detect simultaneously, and the temperature signal can be used to further correct the pressure signal, further improving the detection accuracy.

[0015] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic cross-sectional view of a sensor assembly provided in an embodiment of this application; Figure 2 This is a schematic cross-sectional view of a sensor assembly provided in an embodiment of this application; Figure 3 This is a top view of the bottom surface of a sensor assembly provided in an embodiment of this application; Figure 4 This is a top view of the sensor assembly provided in one embodiment of this application. Reference numerals: 100-Insulating base layer, 200-Surface acoustic wave pressure sensor, 210-Piezoelectric lithium niobate layer, 211-Cavity, 212-Thinned sensitive diaphragm area, 220-Interdigital transducer, 221-First interdigital transducer, 222-First interdigital transducer, 300-Platinum resistance temperature sensor, 310-Temperature sensor electrode, 320-Resistor, 400-Interdigital capacitive humidity sensor, 410-Interdigital electrode, 420-Humidity-sensitive medium. Detailed Implementation

[0017] The embodiments of this application will now be described in detail with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0018] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0019] In the description of this application, it should be noted that, unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "comprising" or "including," and similar terms used in this application, mean that the element or object preceding the term encompasses the element or object listed following the term and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "inner," "outer," "upper," and "lower" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0020] Temperature, pressure, and humidity are three important parameters in environmental monitoring. In related technologies, environmental monitoring systems typically employ a combination of multiple discrete sensors, resulting in large size, high power consumption, and complex circuit packaging, making it difficult to meet the demands for miniaturization and integration. Furthermore, in the exploration of technologies to miniaturize sensors, it is often difficult to simultaneously achieve miniaturization, high accuracy, and environmental adaptability.

[0021] In view of this, refer to Figure 1 , Figure 2 As shown, the first aspect of this application provides a sensor assembly that improves accuracy and environmental adaptability while achieving miniaturization.

[0022] Sensor components in some embodiments of this application include: The insulating base layer 100 includes a first surface and a second surface disposed opposite to each other; A surface acoustic wave pressure sensor 200 is disposed on the first surface. The surface acoustic wave pressure sensor 200 includes a piezoelectric lithium niobate layer 210 and two pairs of interdigital transducers 220 disposed on the surface of the piezoelectric lithium niobate layer. A cavity 211 and a thinning sensitive membrane region 212 corresponding to the cavity 211 are formed in the piezoelectric lithium niobate layer. The two pairs of interdigital transducers 220 are disposed around the thinning sensitive membrane region 212 in mutually perpendicular directions. A platinum resistance temperature sensor 300 and an interdigital capacitive humidity sensor 400 are disposed on the second surface.

[0023] In the sensor assembly provided in this application embodiment, the platinum resistance temperature sensor 300 and the interdigital capacitive humidity sensor 400 have high detection accuracy and environmental adaptability. By integrating the surface acoustic wave pressure sensor 200, the platinum resistance temperature sensor 300, and the interdigital capacitive humidity sensor 400 onto the first and second surfaces of the insulating base layer 100, crosstalk between the platinum resistance temperature sensor 300 and the interdigital capacitive humidity sensor 400 and the signal of the surface acoustic wave pressure sensor 200 is reduced. By forming a cavity 211 on the piezoelectric lithium niobate layer and attaching one side of the piezoelectric lithium niobate layer to the first surface, the cavity 211 is covered by the insulating base layer 100 to form a blind cavity structure, which can further improve the stability and detection accuracy of the blind cavity structure. By arranging two pairs of interdigital transducers 220 arranged in mutually perpendicular directions around the thinned sensitive diaphragm region 212 and using the mutual adjustment of the signals between the two pairs of interdigital transducers 220, the influence of the force angle can be further reduced on the basis of the highly sensitive blind cavity structure, thereby further improving the detection accuracy. Meanwhile, since the platinum resistance temperature sensor 300 and the surface acoustic wave pressure sensor 200 are respectively set on different surfaces, they can detect simultaneously and use the temperature signal to further correct the pressure signal, thereby further improving the detection accuracy.

[0024] In some embodiments, the insulating base layer is a silicon dioxide layer.

[0025] It is understood that the platinum resistance temperature sensor 300 is a sensor that measures temperature by utilizing the characteristic that the resistance value of a platinum resistance changes with temperature. As an example, the platinum resistance temperature sensor 300 includes a temperature sensor electrode 310 and a resistor 320.

[0026] It is understood that the interdigital capacitive humidity sensor 400 is a sensor that measures humidity by detecting changes in capacitance caused by changes in ambient humidity. As an example, the interdigital capacitive humidity sensor 400 includes interdigital electrodes 410 and a humidity-sensitive medium 420 filled between the interdigital electrodes 410. As an example, the humidity-sensitive medium may be one of polyimide, alumina, titanium dioxide, cellulose acetate, etc.

[0027] In some embodiments, refer to Figure 3 As shown, the length direction of the platinum resistance temperature sensor 300 and the length direction of the interdigital capacitive humidity sensor 400 are parallel to each other. That is, the length direction of the pattern formed by the temperature sensor electrode 310 and the resistor 320 in the platinum resistance temperature sensor 300 is the first direction, and the length direction of the pattern formed by the interdigital electrode 410 and the humidity-sensitive medium 420 is the second direction. The first direction and the second direction are substantially parallel. This arrangement can further reduce the size of the sensor while ensuring the accuracy of both.

[0028] Understandably, choosing a platinum resistance temperature sensor 300 and an interdigital capacitive humidity sensor 400 as the temperature and humidity detection sensors, and placing them on the second surface of the insulating substrate 100, can improve detection accuracy. Furthermore, the temperature sensor electrode 310, resistor 320, and interdigital electrode 410 are directly formed on the second surface using photolithography and magnetron sputtering, and resistance adjustment is performed directly on the same surface using methods such as lasers. This design simplifies the sensor assembly manufacturing process, improves processing efficiency, and thus reduces component costs.

[0029] Reference Figure 4 As shown, as an example, the two pairs of interdigital transducers 220 include a first interdigital transducer pair and a second interdigital transducer pair. The first interdigital transducer pair includes two opposing first interdigital transducers 221, and the second interdigital transducer pair includes two opposing second interdigital transducers 222. The first interdigital transducer pair is arranged along a third direction, and the second interdigital transducer pair is arranged along a fourth direction, with the third direction perpendicular to the fourth direction.

[0030] In some embodiments, the platinum resistance temperature sensor 300 and the interdigitated capacitive humidity sensor 400 are correspondingly arranged with respect to the cavity 211, that is, they are located on opposite sides of the insulating base layer area covered by the cavity 211. This arrangement can further improve the correction accuracy of the temperature detected by the platinum resistance temperature sensor 300 to the pressure parameters of the surface acoustic wave pressure sensor 200.

[0031] In some embodiments, the cavity 211 has a trapezoidal cross-section along a third or fourth direction. Further, the angle between the hypotenuse and the base of the trapezoidal structure is less than 85°. Even further, the angle between the hypotenuse and the base of the trapezoidal structure is between 75° and 85°. Forming a blind cavity on lithium niobate provides higher sensitivity than on insulating layers such as silicon dioxide. Changes in air pressure directly stress the lithium niobate, altering the resonant frequency and phase of the surface acoustic wave. The trapezoidal design guides stress concentration, improving the long-term stability and fatigue resistance of the sensor while further enhancing sensitivity. Compared to some flat-bottomed, steep-walled structures, the trapezoidal structure provides a more gradual contact between the diaphragm and the base under overload conditions, rather than an instantaneous hard contact, offering a buffer for high-voltage measurements.

[0032] In some embodiments, the thickness of the sensitive diaphragm region 212 is reduced to ten times the wavelength of the surface acoustic wave. At this thickness, the acoustic wave energy is attenuated to a very weak level by the time it reaches the bottom surface, and the effect of bottom surface reflection can be ignored, thereby ensuring the pure propagation of the surface acoustic wave.

[0033] In some embodiments, two pairs of interdigital transducers 220 arranged in mutually perpendicular directions are arranged around the thinning sensitive membrane region 212, and at least a portion of the interdigital transducers 220 is located above the thinning sensitive membrane region 212.

[0034] A second aspect of this application provides an electronic device including the sensor assembly described above. This electronic device includes the sensor assembly and therefore also possesses the technical advantages offered by the sensor assembly.

[0035] In the description of this specification, references to terms such as "some embodiments," "examples," or "some examples" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0036] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A sensor assembly, characterized in that, include: An insulating base layer (100) includes a first surface and a second surface disposed opposite to each other; A surface acoustic wave (SAW) pressure sensor (200) is disposed on the first surface. The SAW pressure sensor (200) includes a piezoelectric lithium niobate layer (210) and two pairs of interdigital transducers (220) disposed on the surface of the piezoelectric lithium niobate layer (210). A cavity (211) is formed in the piezoelectric lithium niobate layer (210) and a thinned sensitive membrane region (212) corresponding to the cavity (211). The two pairs of interdigital transducers (220) are disposed around the thinned sensitive membrane region (212) in mutually perpendicular directions. A platinum resistance temperature sensor (300) and an interdigital capacitive humidity sensor (400) are disposed on the second surface.

2. The sensor assembly according to claim 1, characterized in that, The insulating base layer (100) is a silicon dioxide layer.

3. The sensor assembly according to claim 1, characterized in that, The platinum resistance temperature sensor (300) includes a temperature sensor electrode (310) and a resistor (320).

4. The sensor assembly according to claim 1, characterized in that, The interdigitated capacitive humidity sensor (400) includes interdigitated electrodes (410) and a humidity-sensitive medium (420) filled between the interdigitated electrodes (410).

5. The sensor assembly according to claim 4, characterized in that, The length direction of the platinum resistance temperature sensor (300) is parallel to the length direction of the interdigital capacitive humidity sensor (400).

6. The sensor assembly according to any one of claims 1-5, characterized in that, The two pairs of interdigital transducers (220) include a first interdigital transducer pair and a second interdigital transducer pair. The first interdigital transducer pair includes two oppositely arranged first interdigital transducers (221), and the second interdigital transducer pair includes two oppositely arranged second interdigital transducers (222). The first interdigital transducer pair is arranged along a third direction, and the second interdigital transducer pair is arranged along a fourth direction. The third direction is perpendicular to the fourth direction.

7. The sensor assembly according to claim 6, characterized in that, The platinum resistance temperature sensor (300) and the interdigitated capacitive humidity sensor (400) are respectively arranged in relation to the cavity (211).

8. The sensor assembly according to claim 6, characterized in that, The cavity (211) has a trapezoidal cross-section along the third or fourth direction, and / or the thickness of the thinned sensitive diaphragm region (212) is ten times the wavelength of the surface acoustic wave.

9. The sensor assembly according to claim 6, characterized in that, The two pairs of interdigital transducers (220) are arranged around the thinning sensitive membrane region (212), and at least a portion of the two pairs of interdigital transducers (220) are located above the thinning sensitive membrane region (212).

10. An electronic device, characterized in that, Includes the sensor assembly as described in any one of claims 1 to 9.

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