Ultrasonic transducer

Abstract

Embodiments of the present disclosure relate to an ultrasonic transducer. An ultrasonic transducer (910) is proposed, having at least one ultrasonic transducer element, at least one semiconductor chip (911), wherein the semiconductor chip (911) has the ultrasonic transducer element, at least one housing (912), wherein the semiconductor chip (911) is arranged in the housing (912), wherein the semiconductor chip (911) is embedded in a shape-stable encapsulation (913), wherein a contact surface (914) of the encapsulation (913) is provided for acoustically coupling the ultrasonic transducer (910) to a panel (920). An ultrasonic transducer system and a method for mounting an ultrasonic transducer or an ultrasonic transducer system are also proposed.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic transducers, specifically to ultrasonic transducers, ultrasonic transducer systems, and their installation methods. Background Technology

[0002] In many applications, interaction between the user and electronic systems is required. For example, in motor vehicles, switches and corresponding displays are needed to operate windshield vents. Contact sensors are commonly used as switches. Capacitive contact sensors are designed to detect contact at a surface; however, these sensors are limited by the material of that surface. For instance, combining a metallic contact surface with a capacitive contact sensor is often not feasible. In the case of ultrasonic contact sensors based on ultrasonic transducers, the contact surface can be composed of different materials. However, good acoustic coupling with the contact surface is required for reliable contact detection. Summary of the Invention

[0003] Therefore, the object of the present invention is to provide an ultrasonic transducer, an ultrasonic transducer system, and a method that can achieve particularly reliable acoustic coupling.

[0004] An ultrasonic transducer, particularly an ultrasonic contact sensor, is proposed, comprising: at least one ultrasonic transducer element; at least one semiconductor chip having the ultrasonic transducer element; at least one housing, wherein the semiconductor chip is disposed in the housing, wherein the semiconductor chip is embedded in a shape-stable encapsulation, wherein the contact surface of the encapsulation is configured to acoustically couple the ultrasonic transducer to a panel.

[0005] An ultrasonic transducer system, particularly an ultrasonic contact sensor system, is also described, having the aforementioned ultrasonic transducer and a carrier, wherein the carrier is configured for mechanically mounting, particularly gluing and / or screwing and / or clamping, the ultrasonic transducer system to a panel.

[0006] A method for mounting an ultrasonic transducer or ultrasonic transducer system as described above is also described, wherein a coupling intermediate layer is provided between the panel and the ultrasonic transducer. Attached Figure Description

[0007] Examples of the proposed ultrasonic transducers, ultrasonic transducer systems, and methods will now be explained in more detail with reference to the accompanying drawings. These are shown here:

[0008] Figure 1 It is an ultrasonic transducer element;

[0009] Figure 2 It is an ultrasonic transducer element;

[0010] Figure 3 shows the ultrasonic transducer element in the first state;

[0011] Figure 4 shows the ultrasonic transducer element shown in Figure 3 in the second state;

[0012] Figure 5 shows the ultrasonic transducer element in the third state;

[0013] Figure 6 shows the ultrasonic transducer element shown in Figure 6 in the fourth state.

[0014] Figure 7 It is the first ultrasonic transducer system;

[0015] Figure 8 It is the second ultrasonic transducer system;

[0016] Figure 9 It is the third ultrasonic transducer system. Detailed Implementation

[0017] Ultrasonic transducer element 100 in Figure 1 and 2 As shown in the figure, the ultrasonic transducer element 100 has a membrane 120 with electrodes 112 and a substrate 101 with electrodes 111. A cavity 130 is provided between the membrane 120 and the substrate 101, which allows the membrane 120 to move.

[0018] By applying an alternating voltage between electrodes 111 and 112 using a voltage source 151, the diaphragm 120 can be excited to oscillate, enabling the ultrasonic transducer element 100 to emit ultrasonic waves 141.

[0019] Figure 1 and Figure 2 The ultrasonic transducer element 100 shown can also be used to detect ultrasonic waves 142. For this purpose, a DC voltage can be applied between electrodes 111 and 112 using a voltage source 152. The ultrasonic waves 142 can excite the diaphragm 120 to vibrate. As the distance between electrodes 111 and 112 changes, an AC voltage is induced, which can be measured by a measuring device 153.

[0020] Figures 3 to 6 schematically illustrate how contact with panels 390 and 490 is detected on the side opposite the ultrasonic transducer using ultrasonic transducer elements 311 or 411. The ultrasonic transducer elements 311 or 411 are embedded in encapsulation layers 320 and 420, which have contact surfaces through which the ultrasonic transducer is mounted to the panels 390 and 490. The ultrasonic transducer elements 311 and 411 can be fixed to and electrically connected to printed circuit boards 370 and 470, respectively.

[0021] As shown in Figure 3, ultrasonic waves can be generated by the ultrasonic transducer element 311. The ultrasonic waves are transmitted almost entirely through the interface between the encapsulation layer 320 and the panel 390, and then reflected at the free surface of the panel 390 opposite to the encapsulation layer 320. After repeatedly transmitting through the interface between the panel 390 and the encapsulation layer 320, the ultrasonic waves can be detected again by the sensing element 311, thus obtaining an echo signal, as shown in the lower part of Figure 3.

[0022] When the free surface of panel 390 opposite to encapsulation layer 320 is touched, for example by finger 401, only a small portion of the ultrasonic waves are reflected at the free surface and the echo signal is reduced, as shown in the lower part of Figure 4.

[0023] As shown in Figure 5, cavity 491 is retained when the ultrasonic transducer is mounted to panel 490. This cavity 491 ensures that the ultrasonic waves emitted by sensor element 411 are reflected at the interface between encapsulation layer 420 and panel 490 instead of passing through it, thus producing the echo signal shown below.

[0024] Since the ultrasonic waves are not (or hardly) transmitted into the housing, touching the housing 490 with a finger 601 will not cause a change in the echo signal.

[0025] Although capacitive ultrasonic transducer elements 311 and 411 have been described above, the same considerations also apply to piezoelectric ultrasonic transducer elements, especially ultrasonic transceivers that operate based on the piezoelectric measurement principle.

[0026] Figure 7 An ultrasonic transducer 710 is shown, having at least one semiconductor chip 711. The semiconductor chip 711 has ultrasonic transducer elements capable of transmitting and / or receiving ultrasonic waves. The semiconductor chip 711 is arranged in a housing 712. Figure 7 As shown, the semiconductor chip 711 can be connected to the contacts of the housing in a conventional manner via wires so that the ultrasonic transducer 710 can be electrically connected to other circuits.

[0027] Semiconductor chip 711 is embedded in shape-stable encapsulation 713 within housing 712. Contact surface 714 of encapsulation 713 is used to acoustically couple ultrasonic transducer 710 to panel 720. As shown in Figures 3 to 6 and explained in more detail, this allows for detection, for example, by touching cover 720 with finger 750.

[0028] The encapsulation 713 is characterized by its substantially shape-stable nature. In particular, the encapsulation 713 can be designed to substantially maintain its shape under typical contact pressures.

[0029] The encapsulation 713 can be elastic. When the ultrasonic transducer 710 is pressed against the panel 720, the elasticity of the encapsulation 713 ensures permanent, optimal mechanical contact between the contact surface 714 and the surface of the panel 720. In particular, this contact can also be ensured even when the panel 720 is irregularly shaped and / or under vibration.

[0030] Encapsulation 713 can be made of materials including silicone resin and / or polybutadiene and / or acrylate and / or fillers. Fillers can be used in particular to adjust the density of the encapsulation.

[0031] exist Figure 7 In the illustrated embodiment, the contact surface 714 of the encapsulation 713 is convex. Depending on the panel 720 to which the ultrasonic transducer 710 is to be mounted, other configurations of the contact surface 714 may also be considered.

[0032] An ultrasonic transducer 710 can be mounted on a carrier 730, thereby forming an ultrasonic transducer system. The carrier 730 may be specifically configured for mechanically securing, particularly by bonding and / or screwing and / or clamping, the ultrasonic transducer system to a panel 720. Specifically, the ultrasonic transducer system can be mounted to the panel 720 without creating contact between the housing 712 of the ultrasonic transducer 710 and the panel 720. The carrier 730 may, in particular, be a printed circuit board establishing connections from the ultrasonic transducer 710 to evaluation circuitry. The carrier 730 can therefore be used for both mechanical and electrical purposes.

[0033] exist Figure 7 In the middle, the carrier is clamped on the panel 720 by means of the hook 721 and the recess 731 of the panel 720.

[0034] The notch 731 can be regarded as a panel positioning aid 731, used to precisely position the carrier 730 on the panel 720.

[0035] In principle, Figure 8 and 9 The variants shown can also be used in fixed ultrasonic sensor systems. In particular, the type of fixing can be selected regardless of the type of ultrasonic transducer.

[0036] Figure 8 Another ultrasonic transducer 810 is shown. The ultrasonic transducer 810 also has a semiconductor chip 811, which has… Figure 8 An ultrasonic transducer element, not shown. A semiconductor chip 811 is disposed in a housing 812 and embedded in a shape-stable encapsulation 813. The encapsulation 813 is also designed to be shape-stable. A contact surface 814 is used to acoustically couple the ultrasonic transducer 810 to the panel 820.

[0037] The housing 812 of the ultrasonic transducer 810 has a housing positioning aid 815 for positioning the housing 812 on the carrier 830.

[0038] The carrier 830 is configured to screw the ultrasonic transducer system onto the panel 820. For this purpose, the carrier 830 has screws 831 and spacers 832. The spacers 832 can be securely connected to the panel 820 so that the carrier 830 is securely positioned relative to the panel 820 when the carrier 830 is screwed onto the panel 820.

[0039] Alternatively, it is advisable to securely mount the spacer 832 on the carrier 830 and provide corresponding mechanical features on the panel 820, which can ensure the accurate positioning of the carrier 830 relative to the panel 820.

[0040] A coupling interlayer 840 is disposed between the ultrasonic transducer 810, particularly its contact surface 814 and the panel 820. The coupling interlayer may include an adhesive layer and / or a foam layer.

[0041] With the convex design of the contact surface 814 of the encapsulation body 813, the coupling intermediate layer 840 can act as an acoustic lens.

[0042] The coupling intermediate layer 840 can be applied to the ultrasonic transducer 810 before the ultrasonic transducer 810 is mounted to the panel 820. However, it is also possible to mount the coupling intermediate layer 840 to the panel 820 first before mounting the ultrasonic transducer 810.

[0043] Lens effect in Figure 8 The ultrasonic waves 860 refracted at the interface are shown in the figure.

[0044] The sound velocity c2 of the coupling intermediate layer 840 can be higher than the sound velocity c1 of the encapsulation 813.

[0045] If α1 describes the angle with respect to the normal of the contact surface 814, where ultrasonic waves 860 from the ultrasonic transducer element impact the contact surface 814, and α2 describes the corresponding exit angle, then the following applies:

[0046]

[0047] Preferably, the sound velocities c1 and c2 of the encapsulation 813 or the coupling intermediate layer 840, and the densities ρ1 and ρ2 of the encapsulation 813 and the coupling layer 840 are selected such that the encapsulation 813 and the coupling intermediate layer 840 have the same acoustic impedance Z.

[0048] Z = ρ1·c1 = ρ2·c2.

[0049] Figure 9Another ultrasonic transducer 910 is shown. The semiconductor chip 911 of the ultrasonic transducer 910 is arranged in a housing 912 and embedded in a shape-stable encapsulation 913. The contact surface 914 of the encapsulation 913 for acoustically coupling the ultrasonic transducer 910 to the panel 920 is concave.

[0050] The panel positioning aid 931 of the carrier 930 is used to position the carrier 930 on the panel 920, and the carrier 930 is fixed to the panel by means of the adhesive layer 933.

[0051] Although some examples of ultrasonic transducers and / or ultrasonic transducer systems have been explained in conjunction with contact sensors or contact sensor systems, a variety of other applications of the ultrasonic transducers and ultrasonic transducer systems described are possible.

[0052] and Figure 8 In contrast to the example shown, the contact surface 914 of the encapsulation 913 is concave.

[0053] In order to achieve the beam path of the ultrasound 960, the sound velocity value of the coupling intermediate layer 940 is selected to be lower than the sound velocity value of the encapsulation 913.

[0054] Therefore, according to Figure 9 The ultrasonic transducer system can also reliably detect finger contact with panel 920.

[0055] Some exemplary embodiments are defined by the following examples:

[0056] Example 1. An ultrasonic transducer (710, 810, 910) having at least one ultrasonic transducer element,

[0057] It has at least one semiconductor chip (711, 811, 911), wherein the semiconductor chip (711, 811, 911) has an ultrasonic transducer element.

[0058] Having at least one housing (712, 812, 912),

[0059] The semiconductor chips (711, 811, 911) are arranged in housings (712, 812, 912).

[0060] The semiconductor chips (711, 811, 911) are embedded in shape-stable encapsulations (713, 813, 913), wherein the contact surfaces (714, 814, 914) of the encapsulations (713, 813, 913) are configured to acoustically couple the ultrasonic transducers (710, 810, 910) to the panels (720, 820, 920).

[0061] Example 2. An ultrasonic transducer (710, 810, 910) according to Example 1, wherein the encapsulation (713, 813, 913) is elastic.

[0062] Example 3. An ultrasonic transducer (710, 810, 910) according to Example 1 or 2, wherein the encapsulation (713, 813, 913) is made of a material comprising silicone and / or polybutadiene and / or acrylate and / or filler.

[0063] Example 4. An ultrasonic transducer (710, 810) according to any one of Examples 1 to 3, wherein the contact surface (714, 814) of the encapsulation (713, 813) is convex.

[0064] Example 5. An ultrasonic transducer (910) according to any one of Examples 1 to 3, wherein the contact surface (914) of the encapsulation (913) is concave.

[0065] Example 6. An ultrasonic transducer system having:

[0066] According to any one of the preceding Examples 1 to 5, the ultrasonic transducer (710, 810, 910) and

[0067] Carriers (730, 830, 930),

[0068] The carriers (730, 830, 930) are configured to mechanically fix, in particular glue and / or screw and / or clamp, the ultrasonic transducer system to the panel (720, 820, 920).

[0069] Example 7. An ultrasonic transducer system according to Example 6, wherein the carrier (730, 930) has at least one panel positioning aid (731, 931) for positioning the carrier (730, 930) to the panel (720, 920).

[0070] Example 8. An ultrasonic transducer system according to any one of Examples 6 or 7, wherein the housing (812) of the ultrasonic transducer (810) has a housing positioning aid (815) for positioning the housing (812) on the carrier (830).

[0071] Example 9. A method for installing an ultrasonic transducer (810, 910) according to any one of Examples 1 to 5 or an ultrasonic transducer system according to any one of Examples 6 to 8.

[0072] A coupling intermediate layer (840, 940) is provided between the panels (820, 920) and the ultrasonic transducers (810, 910).

[0073] Example 10. According to the method described in Example 9,

[0074] The coupling intermediate layer (840, 940) includes an adhesive layer and / or a foam layer.

[0075] Example 11. The method according to any one of Examples 9 or 10, wherein the sound velocity of the coupling intermediate layer (840) is higher than the sound velocity of the encapsulation (813).

[0076] Example 12. The method according to any one of Examples 9 or 10, wherein the sound velocity of the coupling intermediate layer (940) is lower than the sound velocity of the encapsulation (913).

[0077] Example 13. The method according to any one of Examples 9 to 12, wherein a coupling intermediate layer (840, 940) is applied to the ultrasonic transducer (810, 910) before the ultrasonic transducer (810, 910) or ultrasonic transducer system is mounted to the panel (820, 920).

[0078] Example 14. The method according to any one of Examples 9 to 12, wherein a coupling intermediate layer (840, 940) is applied to the panel (820, 920) before the ultrasonic transducer (810, 910) or ultrasonic transducer system is mounted to the panel (820, 920).

[0079] Although specific embodiments have been illustrated and described in this specification, those skilled in the art will recognize that various alternatives and / or equivalent embodiments can be substituted for the specific embodiments shown and described herein without departing from the scope of this specification. Those deviations shown may be chosen. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, the invention is intended to be limited only by the claims and their equivalents.

Claims

1. An ultrasonic transducer (710, 810, 910), comprising: At least one ultrasonic transducer element; At least one semiconductor chip (711, 811, 911), wherein the semiconductor chip (711, 811, 911) has the ultrasonic transducer element; At least one housing (712, 812, 912). The semiconductor chips (711, 811, 911) are arranged in the housing (712, 812, 912). The semiconductor chips (711, 811, 911) are embedded in shape-stable encapsulations (713, 813, 913). The encapsulation bodies (713, 813, 913) are housed within the housings (712, 812, 912). The contact surfaces (714, 814, 914) of the encapsulation (713, 813, 913) are configured to acoustically couple the ultrasonic transducer (710, 810, 910) to the panel in a direction perpendicular to the top surface of the panel (720, 820, 920).

2. The ultrasonic transducer (710, 810, 910) according to claim 1. The encapsulations (713, 813, 913) are elastic.

3. The ultrasonic transducer (710, 810, 910) according to claim 1 or 2. The encapsulations (713, 813, 913) are made of materials containing silicone and / or polybutadiene and / or acrylate and / or fillers.

4. The ultrasonic transducer (710, 810) according to any one of claims 1 to 3. The contact surfaces (714, 814) of the encapsulation bodies (713, 813) are convex.

5. The ultrasonic transducer (910) according to any one of claims 1 to 3. The contact surface (914) of the encapsulation body (913) is concave.

6. An ultrasonic transducer system, comprising: The ultrasonic transducer (710, 810, 910) according to any one of claims 1 to 5, and Carriers (730, 830, 930). The carriers (730, 830, 930) are configured to mechanically fix the ultrasonic transducer system to the panel (720, 820, 920).

7. The ultrasonic transducer system according to claim 6, The carriers (730, 830, 930) are configured to glue and / or screw and / or clamp the ultrasonic transducer system to the panel (720, 820, 920).

8. The ultrasonic transducer system according to claim 6, The carrier (730, 930) has at least one panel positioning aid (731, 931) for positioning the carrier (730, 930) to the panel (720, 920).

9. The ultrasonic transducer system according to any one of claims 6 or 8, The housing (812) of the ultrasonic transducer (810) has a housing positioning aid (815) for positioning the housing (812) on the carrier (830).

10. A method for installing an ultrasonic transducer (810, 910) according to any one of claims 1 to 5 or an ultrasonic transducer system according to any one of claims 6 to 9, A coupling intermediate layer (840, 940) is provided between the panels (820, 920) and the ultrasonic transducers (810, 910).

11. The method according to claim 10, The coupling intermediate layer (840, 940) includes an adhesive layer and / or a foam layer.

12. The method according to any one of claims 10 or 11, The sound velocity of the coupling intermediate layer (840) is higher than that of the encapsulation body (813).

13. The method according to any one of claims 10 or 11, The sound velocity of the coupling intermediate layer (940) is lower than that of the encapsulation (913).

14. The method according to any one of claims 10 to 13, Before installing the ultrasonic transducer (810, 910) or the ultrasonic transducer system onto the panel (820, 920), the coupling intermediate layer (840, 940) is applied to the ultrasonic transducer (810, 910).

15. The method according to any one of claims 10 to 13, Before installing the ultrasonic transducer (810, 910) or the ultrasonic transducer system onto the panel (820, 920), the coupling intermediate layer (840, 940) is applied to the panel (820, 920).

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