Ultrasonic transducer system

Abstract

Ultrasonic transducer system with an ultrasonic transducer (710, 810, 910) with at least one ultrasonic transducer element, with at least one semiconductor chip (711, 811, 911), wherein the semiconductor chip (711, 811, 911) comprises the ultrasonic transducer element, with at least one housing (712, 812, 912), wherein the semiconductor chip (711, 811, 911) is arranged in the housing (712, 812, 912), wherein the semiconductor chip (711, 811, 911) is embedded in a substantially dimensionally stable encapsulation (713, 813, 913), wherein a contact surface (714, 814, 914) of the encapsulation (713, 813, 913) is arranged for acoustic coupling of the ultrasonic transducer (710, 810, 910) to a covering (720, 820, 920) and with one carrier (730, 830, 930), wherein the carrier (730, 830, 930) is designed for mechanical fastening, in particular gluing and / or screwing and / or clipping, of the ultrasonic transducer system to the cladding (720, 820, 920), wherein the carrier (730, 930) has at least one panel positioning aid (731, 931) for positioning the carrier (730, 930) on the panel (720, 920).

Description

[0001] Many applications require user interaction with an electronic system. For example, a motor vehicle requires a switch to operate the windshield ventilation and a corresponding display. Touch sensors are often used as switches. Capacitive touch sensors are subject to restrictions regarding the material of the surface on which they are intended to detect touches. For example, combining a metal touch surface with a capacitive touch sensor is generally not possible. With ultrasonic touch sensors based on ultrasonic transducers, the touch surface can be made of different materials. However, good acoustic coupling to the touch surface is required to reliably detect a touch.

[0002] WO 2019 / 226680 A1 discloses an ultrasonic transducer device which is installed in a housing made of solidified synthetic resin.

[0003] Further ultrasonic transducer devices are known from US 2021 / 0 239 553 A1, DE 19 957 125 A1, CN 102 873 018 A and WO 2017 / 081 138 A1.

[0004] WO 2017 / 066 612 A1 discloses an ultrasonic transducer with a gel or adhesive as embedding material.

[0005] Based on this, the object of the present invention is to provide an ultrasonic transducer system and a method with which a particularly reliable acoustic coupling is made possible.

[0006] The problem was solved by the subject matter of the main claim and the subordinate claim. Advantageous embodiments are specified in the subclaims.

[0007] The invention relates to an ultrasonic transducer system, in particular an ultrasonic touch sensor system, comprising an ultrasonic transducer, in particular an ultrasonic touch sensor with at least one ultrasonic transducer element, comprising at least one semiconductor chip, wherein the semiconductor chip has the ultrasonic transducer element, comprising at least one housing, wherein the semiconductor chip is arranged in the housing, wherein the semiconductor chip is embedded in a substantially dimensionally stable encapsulation, wherein a contact surface of the encapsulation is configured for the acoustic coupling of the ultrasonic transducer to a casing, and comprising a carrier, wherein the carrier is configured for the mechanical fastening, in particular gluing and / or screwing and / or clipping, of the ultrasonic transducer system to the casing, wherein the carrier has at least one casing positioning aid for positioning the carrier on the casing.

[0008] Furthermore, a method for attaching an ultrasonic transducer system with an ultrasonic transducer having at least one ultrasonic transducer element, with at least one semiconductor chip, wherein the semiconductor chip has the ultrasonic transducer element, with at least one housing, wherein the semiconductor chip is arranged in the housing, wherein the semiconductor chip is embedded in a substantially dimensionally stable encapsulation, wherein a contact surface of the encapsulation is configured for acoustic coupling of the ultrasonic transducer to a casing, and with a carrier, wherein the carrier is configured for mechanical fastening, in particular gluing and / or screwing and / or clipping, of the ultrasonic transducer system to the casing, is described, wherein an intermediate coupling layer is provided between the casing and the ultrasonic transducer,where a sound velocity of the coupling intermediate layer is higher or lower than a sound velocity of the encapsulation.,

[0009] Examples of the proposed ultrasonic transducer system and method are now explained in more detail with reference to the drawing. The drawing shows: Fig. 1 an ultrasonic transducer element; Fig. 2 an ultrasonic transducer element; Fig. 3 an ultrasonic transducer element in a first situation; Fig. 4 that in the Fig. 3 shows the ultrasonic transducer element in a second situation; Fig. 5 an ultrasonic transducer element in a third situation; Fig. 6 that in the Fig. 6 shows the ultrasonic transducer element in a fourth situation; Fig. 7 a first ultrasonic transducer system; Fig. 8 a second ultrasonic transducer system; Fig. 9 a third ultrasonic transducer system.

[0010] In the Fig. 1 and Fig. 2 shows an ultrasonic transducer element 100. The ultrasonic transducer element 100 comprises a membrane 120 with an electrode 112 and a substrate 101 with an electrode 111. A cavity 130 is provided between the membrane 120 and the substrate 101, which enables movement of the membrane 120.

[0011] By applying an alternating voltage between the electrodes 111 and 112 by means of a voltage source 151, the membrane 120 can be excited to vibrate so that the ultrasonic transducer element 100 can emit ultrasonic waves 141.

[0012] The Fig. 1 and Fig. The ultrasonic transducer element 100 shown in Figure 2 can also be used to detect ultrasonic waves 142. For this purpose, a direct voltage can be applied between the electrodes 111 and 112 using the voltage source 152. The ultrasonic waves 142 can excite the membrane 120 to vibrate. The resulting change in the distance between the electrodes 111 and 112 induces an alternating voltage, which can be measured with a measuring device 153.

[0013] In the Fig. 3 to 6 schematically illustrate how contact with a panel 390, 490 on the side of the panel 390, 490 opposite the ultrasonic transducer can be detected by means of the ultrasonic transducer element 311 or 411. The ultrasonic transducer element 311 or 411 is embedded in an encapsulation layer 320, 420, wherein the encapsulation layer 320, 420 has a contact surface with which the ultrasonic transducer is attached to the panel 390, 490. The ultrasonic transducer element 311, 411 can be mounted on a circuit board 370, 470 and electrically connected thereto.

[0014] As in the Fig. 3, ultrasonic waves can be generated by means of the ultrasonic transducer element 311, which are transmitted essentially completely through the interface between the encapsulation layer 320 and the cladding 390 and are then reflected at the free surface of the cladding 390 opposite the encapsulation layer 320. After being transmitted again through the interface between the cladding 390 and the encapsulation layer 320, the ultrasonic waves can be detected again by the sensor element 311, so that an echo signal, as below the Fig. 3 is obtained.

[0015] When the free surface of the covering 390 opposite the encapsulation layer 320 is touched, for example with a finger 401, only a small proportion of the ultrasonic waves is reflected at the free surface and the echo signal decreases, as it is below the Fig. 4 is shown.

[0016] In the Fig. 5 shows that a cavity 491 remains when the ultrasonic transducer is attached to the casing 490. This cavity 491 causes the ultrasonic waves emitted by the sensor element 411 to not pass through the interface between the encapsulation layer 420 and the casing 490, but rather to be reflected at this interface, resulting in an echo signal as shown below.

[0017] Since the ultrasonic waves are not (or almost not) transmitted into the covering, touching the covering 490 with the finger 601 does not lead to a change in the echo signal.

[0018] Although a capacitive ultrasonic transducer element 311, 411 has been described above, corresponding considerations also apply to a piezoelectric ultrasonic transducer element, in particular to ultrasonic transceivers which operate according to a piezoelectric measuring principle.

[0019] In the Fig. 7, an ultrasonic transducer 710 is shown, which has at least one semiconductor chip 711. The semiconductor chip 711 has an ultrasonic transducer element with which ultrasonic waves can be transmitted and / or received. The semiconductor chip 711 is arranged in a housing 712. As shown in FIG. Fig. As indicated in Figure 7, the semiconductor chip 711 can be connected in the usual way with wires to contacts of the housing in order to be able to electrically connect the ultrasonic transducer 710 to further circuits.

[0020] The semiconductor chip 711 is embedded in the housing 712 in a dimensionally stable encapsulation 713. A contact surface 714 of the encapsulation 713 serves for the acoustic coupling of the ultrasonic transducer 710 to a casing 720. This can allow, as in the Fig. 3 to 6 and explained in more detail, to detect the contact of the covering 720 with, for example, a finger 750.

[0021] The encapsulation 713 is characterized by being substantially dimensionally stable. In particular, the encapsulation 713 can be designed such that it substantially retains its shape under typical contact pressures.

[0022] The encapsulation 713 can be elastic. The elasticity of the encapsulation 713 can ensure that permanent, optimal mechanical contact is achieved between the contact surface 714 and the surface of the cladding 720 when the ultrasonic transducer 710 is pressed against the cladding 720. In particular, such contact can be ensured even with irregularly shaped claddings 720 and / or in the event of vibrations.

[0023] The encapsulation 713 can be made of a material comprising silicone and / or polybutadiene and / or acrylate and / or a filler. The filler can, in particular, serve to adjust the density of the encapsulation.

[0024] In the Fig. In the embodiment shown in Figure 7, the contact surface 714 of the encapsulation 713 is convex. Depending on the covering 720 to which the ultrasonic transducer 710 is to be attached, a different design of the contact surface 714 is also conceivable.

[0025] The ultrasonic transducer 710 can be mounted on a carrier 730, thus forming an ultrasonic transducer system. The carrier 730 is configured, in particular, for mechanically fastening the ultrasonic transducer system to the casing 720, in particular by gluing, screwing, and / or clipping. In particular, the ultrasonic transducer system can be mounted on the casing 720 without establishing contact between the housing 712 of the ultrasonic transducer 710 and the casing 720. The carrier 730 can, in particular, be a printed circuit board that establishes a connection from the ultrasonic transducer 710 to an evaluation circuit. The carrier 730 can therefore serve both mechanical and electrical purposes.

[0026] In the Fig. 7, the carrier is clipped to the cover 720 by means of a hook 721 of the cover 720 and a recess 731.

[0027] The recess 731 can be regarded as a panel positioning aid 731, which serves for the precise positioning of the carrier 730 on the panel 720.

[0028] In principle, the variants described in the Fig. 8 and Fig. 9. In particular, the type of attachment can be selected independently of the type of ultrasonic transducer.

[0029] In the Fig. 8 shows a further ultrasonic transducer 810. The ultrasonic transducer 810 again has a semiconductor chip 811, which has a Fig. 8 has an ultrasonic transducer element (not shown). The semiconductor chip 811 is arranged in a housing 812 and embedded in a dimensionally stable encapsulation 813. The encapsulation 813 is, in turn, dimensionally stable. A contact surface 814 serves for the acoustic coupling of the ultrasonic transducer 810 to the casing 820.

[0030] The housing 812 of the ultrasonic transducer 810 has a housing positioning aid 815 for positioning the housing 812 on the carrier 830.

[0031] The carrier 830 is configured for screwing the ultrasonic transducer system to the casing 820. For this purpose, the carrier 830 has a screw 831 and spacers 832. The spacers 832 can be firmly connected to the casing 820, so that when the carrier 830 is screwed to the casing 820, a secure positioning of the carrier 830 with respect to the casing 820 is possible.

[0032] It is also conceivable to provide the spacers 832 fixedly on the carrier 830 and to provide corresponding mechanical features on the casing 820 with which an exact positioning of the carrier 830 with respect to the casing 820 can be ensured.

[0033] A coupling intermediate layer 840 is provided between the ultrasonic transducer 810, in particular its contact surface 814, and the covering 820. The coupling intermediate layer can comprise an adhesive layer and / or a foam layer.

[0034] Together with the convex design of the contact surface 814 of the encapsulation 813, the coupling intermediate layer 840 can act as an acoustic lens.

[0035] The coupling intermediate layer 840 can be applied to the ultrasonic transducer 810 before attaching the ultrasonic transducer 810 to the casing 820. However, it is also conceivable that the coupling intermediate layer 840 is first attached to the casing 820 before attaching the ultrasonic transducer 810.

[0036] The lens effect is in the Fig. 8 is represented by the ultrasonic waves 860 refracted at the interface.

[0037] A sound velocity c2 of the coupling intermediate layer 840 may be higher than a sound velocity c1 of the encapsulation 813.

[0038] If alpha one describes the angle to the normal of the contact surface 814 at which the ultrasonic waves 860 from the ultrasonic transducer element hit the contact surface 814 and alpha two the corresponding angle of reflection: sin α1c1=sin α2c2

[0039] Preferably, the sound velocities c1 and c2 of the encapsulation 813 and the coupling intermediate layer 840, respectively, and the density ρ1 of the encapsulation 813 and ρ2 of the coupling layer 840 are selected such that the encapsulation 813 and the coupling intermediate layer 840 have the same acoustic impedance Z: z=ρ1⋅c1=ρ2⋅c2

[0040] In the Fig. 9 shows another ultrasonic transducer 910. The semiconductor chip 911 of the ultrasonic transducer 910 is arranged in a housing 912 and embedded in the dimensionally stable encapsulation 913. The contact surface 914 of the encapsulation 913, which serves for the acoustic coupling of the ultrasonic transducer 910 to the casing 920, is concavely shaped.

[0041] A panel positioning aid 931 of the carrier 930 serves to position the carrier 930 on the panel 920, to which the carrier 930 is attached by means of an adhesive layer 933.

[0042] Although some examples of the ultrasonic transducer and / or the ultrasonic transducer system have been explained in connection with touch sensors or touch sensor systems, a wide variety of other applications of the described ultrasonic transducers and ultrasonic transducer systems are possible.

[0043] In contrast to the Fig. In the example shown in Figure 8, the contact surface 914 of the encapsulation 913 is concave.

[0044] To achieve the beam path of the ultrasonic waves 960, a lower value is selected for the sound velocity of the coupling intermediate layer 940 than for the sound velocity of the encapsulation 913.

[0045] Also with the ultrasonic transducer system according to Fig. 9, contact of the cover 920 with a finger 950 can therefore be reliably detected.

[0046] Some embodiments are defined by the following examples: EXAMPLE 1. Ultrasonic transducer (710, 810, 910) with at least one ultrasonic transducer element, with at least one semiconductor chip (711, 811, 911), wherein the semiconductor chip (711, 811, 911) has the ultrasonic transducer element, with at least one housing (712, 812, 912), wherein the semiconductor chip (711, 811, 911) is arranged in the housing (712, 812, 912), wherein the semiconductor chip (711, 811, 911) is embedded in a dimensionally stable encapsulation (713, 813, 913), wherein a contact surface (714, 814, 914) of the encapsulation (713, 813, 913) is arranged for acoustic coupling of the ultrasonic transducer (710, 810, 910) to a casing (720, 820, 920). EXAMPLE 2. Ultrasonic transducer (710, 810, 910) according to EXAMPLE 1, wherein the encapsulation (713, 813, 913) is elastic. EXAMPLE 3. 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 a filler. EXAMPLE 4. Ultrasonic transducer (710, 810) according to one of EXAMPLES 1 to 3, wherein the contact surface (714, 814) of the encapsulation (713, 813) is convex. EXAMPLE 5. Ultrasonic transducer (910) according to one of EXAMPLES 1 to 3, wherein the contact surface (914) of the encapsulation (913) is concave. EXAMPLE 6. Ultrasonic transducer system with an ultrasonic transducer (710, 810, 910) according to one of the preceding EXAMPLES 1 to 5, and a carrier (730, 830, 930), wherein the carrier (730, 830, 930) is designed for mechanical fastening, in particular gluing and / or screwing and / or clipping, of the ultrasonic transducer system to the cladding (720, 820, 920). EXAMPLE 7. 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) on the panel (720, 920). EXAMPLE 8. Ultrasonic transducer system according to 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). EXAMPLE 9. A method of mounting 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, wherein an intermediate coupling layer (840, 940) is provided between the cladding (820, 920) and the ultrasonic transducer (810, 910). EXAMPLE 10. Procedure according to EXAMPLE 9, wherein the coupling intermediate layer (840, 940) comprises an adhesive layer and / or a foam layer. EXAMPLE 11. The method of any one of EXAMPLES 9 or 10, wherein a sound velocity of the coupling interface layer (840) is higher than a sound velocity of the encapsulation (813). EXAMPLE 12. The method of any one of EXAMPLES 9 or 10, wherein a speed of sound of the coupling interface layer (940) is lower than a speed of sound of the encapsulation (913). EXAMPLE 13. The method according to any one of EXAMPLES 9 to 12, wherein the coupling intermediate layer (840, 940) is applied to the ultrasonic transducer (810, 910) before attaching the ultrasonic transducer (810, 910) or the ultrasonic transducer system to the casing (820, 920). EXAMPLE 14. The method according to any one of EXAMPLES 9 to 12, wherein the coupling intermediate layer (840, 940) is applied to the cladding (820, 920) before attaching the ultrasonic transducer (810, 910) or the ultrasonic transducer system to the cladding (820, 920).

[0047] Although specific embodiments have been illustrated and described in this specification, those of ordinary skill in the art will recognize that a variety of alternative and / or equivalent implementations may be chosen as substitutions for the specific embodiments shown and described in this specification without departing from the scope of the invention shown. It is the intention that this application cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents of the claims.

Claims

[1] Ultrasonic transducer system with an ultrasonic transducer (710, 810, 910) with at least one ultrasonic transducer element, with at least one semiconductor chip (711, 811, 911), wherein the semiconductor chip (711, 811, 911) comprises the ultrasonic transducer element, with at least one housing (712, 812, 912), wherein the semiconductor chip (711, 811, 911) is arranged in the housing (712, 812, 912), wherein the semiconductor chip (711, 811, 911) is embedded in a substantially dimensionally stable encapsulation (713, 813, 913), wherein a contact surface (714, 814, 914) of the encapsulation (713, 813, 913) is arranged for acoustic coupling of the ultrasonic transducer (710, 810, 910) to a covering (720, 820, 920) and with one carrier (730, 830, 930), wherein the carrier (730, 830, 930) is designed for mechanical fastening, in particular gluing and / or screwing and / or clipping, of the ultrasonic transducer system to the cladding (720, 820, 920), wherein the carrier (730, 930) has at least one panel positioning aid (731, 931) for positioning the carrier (730, 930) on the panel (720, 920). [2] Ultrasonic transducer system according to claim 1, wherein the encapsulation (713, 813, 913) is elastic. [3] Ultrasonic transducer system according to claim 1 or 2, wherein the encapsulation (713, 813, 913) is made of a material comprising silicone and / or polybutadiene and / or acrylate and / or a filler. [4] Ultrasonic transducer system according to one of claims 1 to 3, wherein the contact surface (714, 814) of the encapsulation (713, 813) is convex. [5] Ultrasonic transducer system according to one of claims 1 to 3, wherein the contact surface (914) of the encapsulation (913) is concave. [6] Ultrasonic transducer system according to one of claims 1 to 5, wherein the housing (812) of the ultrasonic transducer (810) has a housing positioning aid (815) for positioning the housing (812) on the carrier (830). [7] Method for attaching an ultrasonic transducer system with an ultrasonic transducer (710, 810, 910) with at least one ultrasonic transducer element, with at least one semiconductor chip (711, 811, 911), wherein the semiconductor chip (711, 811, 911) comprises the ultrasonic transducer element, with at least one housing (712, 812, 912), wherein the semiconductor chip (711, 811, 911) is arranged in the housing (712, 812, 912), wherein the semiconductor chip (711, 811, 911) is embedded in a substantially dimensionally stable encapsulation (713, 813, 913), wherein a contact surface (714, 814, 914) of the encapsulation (713, 813, 913) is arranged for acoustic coupling of the ultrasonic transducer (710, 810, 910) to a covering (720, 820, 920) and with one carrier (730, 830, 930), wherein the carrier (730, 830, 930) is designed for mechanical fastening, in particular gluing and / or screwing and / or clipping, of the ultrasonic transducer system to the cladding (720, 820, 920), wherein a coupling intermediate layer (840, 940) is provided between the cladding (820, 920) and the ultrasonic transducer (810, 910), wherein a sound velocity of the coupling intermediate layer (840) is higher or lower than a sound velocity of the encapsulation (813). [8] Method according to claim 7, wherein the ultrasonic transducer system is designed according to one of claims 1 to 6. [9] Method according to claim 7 or 8, wherein the coupling intermediate layer (840, 940) comprises an adhesive layer and / or a foam layer. [10] Method according to one of claims 7 to 9, wherein the coupling intermediate layer (840, 940) is applied to the ultrasonic transducer (810, 910) before the ultrasonic transducer (810, 910) or the ultrasonic transducer system is attached to the cladding (820, 920). [11] Method according to one of claims 7 to 9, wherein the coupling intermediate layer (840, 940) is applied to the cladding (820, 920) before the ultrasonic transducer (810, 910) or the ultrasonic transducer system is attached to the cladding (820, 920).

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