DE102011079646A1 - Ultrasonic sensor device for detecting and / or transmitting ultrasound - Google Patents

Abstract

The present invention relates to an ultrasonic sensor device (1) for detecting and / or transmitting ultrasound (2). In order to improve the sensitivity for detecting an object, the ultrasonic sensor device (1) comprises a plurality of ultrasonic sensor elements (3a, b), each ultrasonic sensor element (3a, b) comprising: a base body (4) having an opening (5a, b ), a flexible bending element (6a, b) which closes the end face of a first end region (A) of the opening (5a, b), wherein the flexible bending element (6a, b) comprises a polymer, in particular a liquid crystal polymer, a piezo element ( 7a, b) which is arranged in the opening (5a, b) and connected to the flexible bending element (6a, b), and a damping element (8a, b) which is arranged in the opening (5a, b) and the front side a second end region (B) of the opening (5a, b) closes.

Description

The invention relates to an ultrasonic sensor element for detecting and / or transmitting ultrasound, an ultrasonic sensor device for detecting and / or transmitting ultrasound and a method for producing an ultrasonic sensor device for detecting and / or transmitting ultrasound.

State of the art

Ultrasonic parking devices are used to detect an object in a space in front of and / or behind a vehicle by means of ultrasonic fields and usually have 4 to 6 ultrasonic sensor devices, which are each arranged in a rear and / or front bumper of the vehicle. Each of the ultrasonic sensor devices in each case has an ultrasonic sensor element which operates selectively in the detection or transmission mode. The ultrasonic sensor devices are arranged relative to each other in the rear and / or front bumper so that the ultrasonic sensor devices are horizontally aligned, so that ground reflections of the ultrasound are either not detected or hidden. Usually, the ultrasonic parking devices have only a warning function for the object detection in sound field space.

US 2008/0060439 A1 describes an ultrasonic sensor element usable for a distance measurement in a vehicle.

Disclosure of the invention

The present invention relates to an ultrasonic sensor element for detecting and / or transmitting ultrasound, wherein the ultrasonic sensor element comprises a base body which has an opening, a flexible bending element which closes a first end region of the opening on the front side, wherein the flexible bending element is a polymer, in particular a liquid crystal polymer , comprising a piezoelectric element arranged in the opening and connected to the flexible bending element, and a damping element which is arranged in the opening and closes the end face of a second end region of the opening.

Another object of the present invention is an ultrasonic sensor device for detecting and / or transmitting ultrasound, wherein the ultrasonic sensor device comprises a plurality of ultrasonic sensor elements, each ultrasonic sensor element having a base body, which has an opening, a flexible bending element which closes a first end region of the opening frontally a piezoelectric element which is arranged in the opening and connected to the flexible bending element, a damping element which is arranged in the opening and the end faces a second end portion of the opening, wherein the base body of the ultrasonic sensor elements of the plurality of ultrasonic sensor elements are integrally formed.

A flexible bending element may, in particular, be understood to mean a bendable element which may be made of a bendable, flexible material and therefore can be bent particularly easily in one or more directions. In particular, the flexible bending element may be configured to perform vibrations.

A piezoelectric element may, in particular, be understood as an element formed as a piezoceramic, which may be formed, for example, on lead zirconate titanate (PZT) -based.

A damping element can in particular be understood as an element which can attenuate or eliminate acoustic (ie sound) and / or mechanical vibrations. In particular, the damping element can cause backscattering sound to be attenuated and / or a characteristic of an ultrasound sensor element and the ultrasound sensor device to be improved, in particular a bandwidth of a transmission characteristic of the ultrasound sensor element and the ultrasound sensor device can be increased.

The ultrasound sensor element and the ultrasound sensor device can have a high resolution, in particular transversely to a longitudinal extent of the ultrasound sensor element, ie, for example, with respect to a bottom in the horizontal and / or vertical direction, when detecting an object in a spatial area adjacent to the ultrasound sensor element and / or to the ultrasound sensor device. Furthermore, a three-dimensional detection of the object by the plurality of ultrasonic sensor elements may be made possible. Furthermore, a distance and / or an angle to the object can be determined based on information that can be determined by means of the plurality of ultrasonic sensor elements.

The flexible polymer-based flexure may thereby contribute to accurate, high-resolution scanning of the surroundings of the ultrasonic sensor element and the ultrasonic sensor device, since such an ultrasonic sensor element may have a high sensitivity.

The piezoelectric element, in particular an electrode of the piezoelectric element, can in particular be connected in an electrically conductive manner to the flexible bending element and the main body, and this Ultrasonic sensor element may have a further electrical contacting of an opposite electrode of the piezoelectric element to a substrate.

The flexible bending element may in particular be designed to be electrically conductive.

The main body of the sensor element may in particular be formed as a hollow cylinder, in or on which the other elements of the ultrasonic sensor element may be arranged. In particular, in a process step by means of injection molding, the flexible bending element formed as a polymer membrane and a connection of the hollow cylinder and a remaining housing can be created. A cross section of the hollow cylinder may be circular or rectangular according to a cross section of the opening.

The main body may in particular also be formed as a plate. Alternatively or additionally, the base body may in particular comprise metal, in particular aluminum, metal oxide, in particular aluminum oxide, and / or a metal oxide ceramic, in particular an aluminum oxide ceramic. The metal oxide may, in particular in the case of aluminum oxide, correspond to the metal oxide ceramic. This can allow a particularly simple and cost-effective production of the ultrasonic sensor element and the ultrasonic sensor device, since the base body have a simple shape and / or the material of the base body can be processed particularly easily.

An outer surface of the flexible bending element may in particular be designed to be flush with an outer surface of the base body, so that the ultrasonic sensor element has no exposed edges and damage to the ultrasonic sensor element can be avoided. The term "outer" top may in the present application designate an outwardly facing top or surface of the element.

In one embodiment, the flexible bending element comprises a polymer, in particular a liquid crystal polymer (English: liquid crystal polymer), more particularly a polymer of the specification A950 from Tikona. As an alternative to a liquid crystal polymer, an elastomer having a similar modulus of elasticity, chemical resistance, etc. may be formed. Alternatively, or in addition to Tikona polymer material A950, at least one liquid crystal polymer may be selected from a group consisting of Sumika Superfin liquid crystal polymer of Sumitomo Chemical Industry specification, Ticona Vectra liquid crystal polymer, Solvay Xydar liquid crystal polymer and Zenite specification liquid crystal polymer of Ticona be used. In particular, the polymer-comprising material may have at least one of the following properties: an attenuation behavior which may be similar to rubber (and, for example, with an attenuation constant of about 0.6); a modulus of elasticity which may be particularly low (for example, between about ≥ 7 GPa and about ≦ 10 GPa); good flowability; a high heat resistance; and a coefficient of linear expansion which may be similar to a coefficient of linear expansion of a material of the body (and may be, for example, between about ≥ 15 × 10 ^-6 / K) and about ≦ 20 × 10 ^-6 / K).

Further, the flexible polymer-based flexure element may enable crosstalk attenuation between adjacent ultrasonic sensor elements of the ultrasonic sensor device, so that the resolution of the ultrasonic device may be further improved. Furthermore, the ultrasonic sensor element may have a high density, since the polymer-based material of the flexible bending element may be impermeable to environmental influences, for example water. In particular, the flexible polymer-based flexure may further provide sufficient protection against chipping so that the attachment of an additional cover layer to the exterior of the flexible flexure may be avoided, which could reduce sensitivity of the ultrasonic sensor element and the ultrasonic sensor device. Furthermore, polymer can be processed particularly easily, so that a surface waviness of the flexible bending element can be avoided, and a surface of the flexible bending element can be directly painted especially after an (inline) plasma treatment and / or coating. Further process steps in the production of the ultrasonic sensor element and the ultrasonic sensor device can thereby be dispensed with.

The polymer of the flexible bending element may in particular be electrically conductive, so that a contacting of the piezoelectric element and the base body via the flexible bending element can be effected.

The flexible flexure may be disposed within the first end region of the opening that may extend through the body. Therefore, the end closure of the opening by the flexible bending element can be achieved in that the flexible bending element can abut a portion of inner side walls of the base body. This causes a high density of the ultrasonic sensor element. The ultrasonic sensor element can in particular in a production of the main body of a dimensionally stable material, in particular metal, metal oxide or metal oxide ceramic, and the flexible flexure of polymer have a high density and / or a steam jet test, as can be performed for test purposes of the ultrasonic sensor element of an ultrasonic parking device, withstand, since the flexure in a direction transverse to seen a longitudinal extent of the opening, in particular seen in the radial direction of the opening, can be kept stable in position. In the case of a base body having a metal, metal oxide or metal oxide ceramic, in particular the high tightness during a multiplicity of temperature changes, which are carried out, for example, in a thermal shock test, can be achieved by virtue of the fact that a thermal conductivity of metal is greater than a thermal conductivity of polymer and the body becomes faster as the flexible flexure can cool. This can cause the material of the base body (despite possibly similar coefficients of linear expansion of the respective materials) to contract faster than the bending element, whereby the opening of the base body during cooling in relation to the expansion reduction of the flexible bending element becomes smaller faster and thus the high density of the ultrasonic sensor element can be achieved. Furthermore, due to the similar coefficients of linear expansion of metal and polymer temperature-related long-term changes in the materials of the body and the flexible bending element can be avoided.

In the context of one embodiment, the flexible bending element and the base body are integrally formed, that is, made of a same material, wherein a material of the flexible bending element and the base body in particular metal, in particular aluminum, metal oxide, in particular alumina, and / or metal oxide, in particular alumina ceramic having , The opening can not run through the body through, so be a blind hole. Therefore, the ultrasonic sensor element can be manufactured inexpensively and easily. The flexible bending element can in this case be made sufficiently thin to ensure flexibility of the flexible bending element.

The piezoelectric element can be deformable in a direction transversely, in particular perpendicular, to a longitudinal extent of the opening, in particular in the radial direction of the opening. The deformation may cause or be caused by a charge shift in the piezo element. For this purpose, in particular a crystal structure of the piezoelectric element can have a corresponding polarization, which effects the deformation or the charge displacement. Consequently, the flexible bending element and the piezoelectric element, which may be mechanically fixed to one another, for example by gluing, perform a bending or a mechanical oscillation in the direction of the longitudinal extent of the opening, ie in particular along a longitudinal extent of the ultrasonic sensor element, since the flexible bending element is full can be connected to the body. Upon receipt of the ultrasound, in particular a pressure action on the flexible bending element can cause a deformation of the flexible bending element and the piezoelectric element. In this way, a charge shift can be generated in the piezoelectric element, which can be detected as a signal. When emitting the ultrasound, an induced charge on the piezoelectric element may cause a deformation of the piezoelectric element and the flexible bending element, so that an ultrasonic wave can be emitted. The emitted ultrasound may therefore be directed along a longitudinal extent of the ultrasound sensor element, and a sensitivity of the ultrasound sensor device for the received ultrasound, which may propagate along the longitudinal extent of the opening, may be particularly good.

In particular, the piezoelectric element can be arranged at a distance from the base body (seen in the transverse direction, in particular in the radial direction, of the opening), whereby a deformation of the piezoelectric element in this direction of the opening can not be restricted. The piezoelectric element may be disc-shaped.

Within the scope of a further embodiment, a substrate, for example exclusively, is arranged along an outer surface of the base body adjacent to the damping element. As a result, the base body can be fastened to the substrate by means of a side of the ultrasonic sensor element facing away from the bending element and / or the piezoelement can be electrically contacted to the substrate without a sensitivity of the ultrasonic sensor element being impaired.

The substrate may be flexible (for example as a flexible printed circuit board) or fixed (for example as a solid, non-bendable printed circuit board).

An electrically conductive, in particular metal, layer may be arranged in particular along a side facing the piezoelectric element side of the flexible bending element, along inner side walls of the base body and along an outer upper side of the base body adjacent to the substrate. A bonding connection, for example a bonding wire, may be provided in particular between a side of the piezoelectric element facing the damping element and the substrate and attached by means of bonding or friction welding. This causes an electrical contact of the Piezoelectric element and the substrate, in particular in the case of an electrically non-conductive base body and an electrically non-conductive flexible bending element. The base body may comprise metal oxide and the flexible bending element may comprise a non-conductive polymer. The metallization can be a ground contact of the piezoelectric element and the bond connection can form a signal line for signal supply to or signal derivation from the piezoelectric element. A corresponding first and second contact of the piezoelectric element can be mounted on opposite surfaces of the piezoelectric element.

Alternatively, in particular in the case of an electrically non-conductive main body, in particular two bond connections, for example in the form of bonding wires or thin conductors connected by friction welding, may be provided between a side of the piezoelectric element facing the damping element and the substrate. This causes an electrical contacting of the piezoelectric element and the substrate.

Alternatively, in particular in the case of an electrically conductive base body and an electrically conductive (polymer-comprising) flexible bending element, a bond connection, for example in the form of a bonding wire or a thin conductor connected by friction welding, can be provided between a side of the piezoelectric element facing the damping element and the substrate. A ground contact of the piezoelectric element can be accomplished via an electrically conductive connection between the piezoelectric element and the flexible bending element (for example in the form of an adhesive bond or a metallization) and an electrically conductive connection between the flexible bending element and the main body (for example in the form of an adhesive bond or metallization) become.

The piezoelectric element and the flexible bending element can in particular also be adhesively bonded together by means of an anisotropic and / or isotropic conductive adhesive in order to produce an electrically conductive connection of the two elements. Anisotropic conductive adhesives may have a base substance in which small silver spheres having a diameter in a range of about ≥ 5 microns (μm) to about ≦ about 10 microns may be embedded. The anisotropic conductive adhesive can only become electrically conductive when both contact partners to be bonded experience pressure and temperature, since without applying the pressure at a temperature-assisted curing of the adhesive, the small silver balls can not come into contact with both contact partners. The anisotropic adhesive may provide the thin adhesive layer thicknesses having a high elastic modulus required for the ultrasonic sensor element and the ultrasonic sensor device. Isotropic conductive adhesives can have a base substance in which silver flakes are arranged with a dimension in a range of about ≥ 20 microns to about ≤ 70 microns, and cause an electrical contact without pressure on both contact partners during curing.

The base body and the substrate can be glued together in particular by means of an (isotropic) conductive adhesive in order to effect an electrically conductive connection of the two elements.

The damping element can be designed in particular as (in particular polymer, for example polyurethane or polypropylene or silicone) foam, so that the ultrasonic sensor element can be manufactured in a particularly simple and cost-effective manner. Furthermore, the ultrasound sensor element can also already have a comparatively high density in the region of the damping element, since the foam can largely seal the ultrasound sensor element against external environmental influences.

In the context of a further embodiment, the ultrasonic sensor element further comprises a cover element, which extends along an outer upper side of the main body adjacent to the bending element and an outer upper side of the bending element, which faces away from the piezoelectric element. The cover element may in particular be designed as a cover layer and / or manufactured by means of injection molding techniques. The cover member may allow additional protection of the ultrasonic sensor element from environmental influences.

The cover element may in particular comprise a polymer, in particular a liquid crystal polymer, more particularly a liquid crystal polymer of the specification A950 from Ticona, and in particular also be electrically conductive. The material of the cover element and the material of the flexible bending element may in particular be identical and / or be producible in a common process step, for example by means of extrusion coating.

In the context of a further embodiment, an outer upper side of the base body adjacent to the flexible bending element and / or an outer upper side of the flexible bending element, which faces away from the piezoelectric element, and / or an outer upper side of the cover element is at least partially curved. The outer upper side of the main body, the outer upper side of the flexible bending element and / or the outer upper side of the cover element may in particular be designed as exposed upper sides of the respective elements. This can be a surface contour of the ultrasonic sensor element may be adapted to a surface shape, in particular to radii, of a bumper of a bumper of a vehicle. This can be particularly favorable in an integration of the ultrasonic sensor device in outer corners of the bumper of the vehicle. When manufacturing the flexible bending element, the base body and / or the bending element by means of injection molding techniques, the surface shaping of the base body, the flexible bending element and / or the cover element to a surface contour of the bumper can be particularly easily implemented. In particular, only the upper side of the cover element can be designed to be at least partially curved, so that an operation of the underlying bending element can not be impaired.

In a further embodiment, the ultrasound sensor elements of the plurality of ultrasound sensor elements (seen in plan view or in view from below onto the ultrasound sensor device) are arranged in a one-dimensional or two-dimensional pattern. The arrangement of the ultrasonic sensor elements in a one-dimensional pattern can be realized, for example, linearly, that is to say as a one-dimensional field. The ultrasonic sensor elements may in particular be arranged in a matrix pattern (for example with six elements in a first direction and three elements in a second direction, which may be transverse, in particular perpendicular, to the first direction). In particular, the two-dimensional pattern may have a circular area and / or the ultrasonic sensor elements may be arranged along a circumferential line of the circular area. The patterned arrangement of the ultrasound sensor elements can bring about a space-saving arrangement of the ultrasound sensor elements and / or allow a vertical and horizontal sensitivity of the ultrasound sensor device with respect to the longitudinal extension of the ultrasound sensor elements and thus a three-dimensional detection of an object.

In a further embodiment, the ultrasound sensor elements of the plurality of ultrasound sensor elements are arranged for transmitting and / or receiving the ultrasound. In a transmission mode of an ultrasonic sensor element, a sound wave can be generated based on a deformation of the bending element, which can be caused by a deformation of the piezoelectric element. The deformation of the piezoelectric element can be caused by a high voltage at the piezoelectric element. In a receiving operation of an ultrasonic sensor element, an (electrical) signal can be generated by a displacement of charges in the piezoelectric element based on a deformation of the bending element. The deformation can be caused by a pressure on the flexible bending element. The ultrasound sensor device can be set up exclusively for transmitting or exclusively for receiving ultrasound. Furthermore, the ultrasound sensor device can be set up at the same time for transmitting and detecting the ultrasound, for example by having a part of the ultrasound sensor elements of the ultrasound sensor device for transmitting the ultrasound and another part of the ultrasound sensor element of the ultrasound sensor device configured to receive the ultrasound. In the case where an ultrasonic sensor element or exclusively ultrasonic sensor elements of one operating mode are present, the ultrasonic sensor element and the ultrasonic sensor elements of the one operating mode can be set up sequentially for transmitting and for receiving the ultrasound. An operating mode of at least one ultrasound sensor element may be changeable in particular during operation of the ultrasound sensor device into the other operating mode.

A plurality of, in particular surface-mounted devices (SMD)) capacitors, may in particular be arranged on an upper side of the substrate facing away from the main body, which may be connected in parallel to the piezo elements of the ultrasonic elements. This measure effects sensitivity drift compensation of the ultrasonic sensor device. Furthermore, a spatially very close arrangement of the capacitors and the ultrasonic sensor elements can be accomplished by the pattern-like arrangement of the ultrasonic sensor elements, since the pattern-like arrangement of the ultrasonic sensor elements on the substrate can have a small footprint.

In a further embodiment, the ultrasonic sensor device is accommodated in a parking device or in a maneuver assistance system of a vehicle. As a result, an object in an environment of a rear and / or front bumper of the vehicle can be detected by means of the ultrasonic sensor device and its angle to the vehicle can be determined, for example, by means of a so-called Bartlet Beam Forming Algorithm. The distance to the object may result from the time information between the emitted ultrasound and the received ultrasound, which may be reflected at the object.

The main body may in particular have a length of about 50 millimeters (mm) and a width of about 30 mm. A thickness of the main body along a longitudinal extent of the opening may in particular be between about 5 mm and about 6 mm.

In the case of Tikona A950 in particular, a thickness of the flexible bending element at most about ≤ 1 mm. In the case of a metal bending element, in particular, a thickness of the bending element may be about 0.3 mm. A diameter of a bending element having a circular cross-section may in particular be in a range of approximately ≥ 4 to approximately ≦ 5 mm. In these cases, crosstalk attenuation between the ultrasonic sensor elements may be about 20 decibels (dB).

In particular, a resonant frequency of the flexible flexure may be about 50 kilohertz (kHz). The resonant frequency of the flexible bending element may be adjustable depending on a shape of the flexible bending element, in particular depending on a thickness of the flexible bending element and a diameter and the modulus of elasticity of the material used of the flexible bending element.

In particular, a thickness of the cover element may be about 0.4 mm. This can ensure that sensitivity of the ultrasonic sensor device to the ultrasound can not be reduced by the cover member.

In particular, a radius of the ultrasonic sensor elements having a circular cross section may be about 2.5 mm, and a distance of directly adjacent ultrasonic sensor elements may be between about ≥ 1 mm and about ≦ 3 mm.

The number of ultrasonic sensor elements in the ultrasonic sensor device can be very diverse. In particular, from an economic point of view, the ultrasonic sensor device can have up to 20 ultrasonic sensor elements.

A detected angular range transverse to and centered about the longitudinal extent of an ultrasonic sensor element may, in particular, be in a range of approximately ≥ 70 degrees to approximately ≦ 80 degrees. A detected angular range transverse to and centered about the longitudinal extension of the ultrasonic sensor device may, in particular, be in a range of approximately ≥ 140 degrees to approximately ≦ 160 degrees.

In particular, the ultrasonic sensor element and / or the ultrasonic sensor device may be manufactured by a method which will be described below.

With regard to further advantages and features of the device according to the invention, reference is hereby explicitly made to the explanations in connection with the method according to the invention and the description of the figures.

• – Bereitstellen eines Grundkörpers, welcher eine Öffnung aufweist,
• – Stirnseitiges Verschließen eines ersten Endbereichs der Öffnung durch ein flexibles Biegeelement,
• – Anordnen eines Piezoelements in der Öffnung,
• – Miteinander-Verbinden des flexiblen Biegeelements und des Piezoelements,
• – Anordnen eines Dämpfungselements in der Öffnung, und
• – Stirnseitiges Verschließen eines zweiten Endbereichs der Öffnung durch das Dämpfungselement,

wobei die Grundkörper der Ultraschallsensorelemente der Vielzahl der Ultraschallsensorelemente einstückig ausgebildet werden.A further subject of the present invention is a method for producing an ultrasound sensor device for detecting and / or transmitting ultrasound, the ultrasound sensor device having a plurality of ultrasound sensor elements, wherein producing an ultrasound sensor element comprises:

• Providing a base body which has an opening,
• Closing a first end region of the opening on the face side by means of a flexible bending element,
• Arranging a piezoelectric element in the opening,
• Connecting the flexible bending element and the piezo element to each other,
• - placing a damping element in the opening, and
• Closing a second end region of the opening on the side by the damping element,

wherein the main body of the ultrasonic sensor elements of the plurality of ultrasonic sensor elements are formed integrally.

For the effect of the method, reference is made to the explanations in connection with the device. Furthermore, the method can be carried out particularly simply, since known measures, in particular injection molding techniques, encapsulation of elements, extrusions, etc., and commercially available tools for producing the ultrasonic sensor element and / or the ultrasonic sensor device can be used. This may enable mass production of the ultrasonic sensor elements, so that manufacturing costs of the ultrasonic sensor device may be particularly small.

In one embodiment, the provision of the base body introducing the opening in the body by means of drilling, eroding or extrusion, in particular cold extrusion on.

In this case, the provision of the main body can have the introduction of a bore in the base body, which can form the opening. As a result, a particularly simple and cost-effective production of the ultrasonic sensor device can be made possible. The opening may be an opening going through the base or not going through.

By eroding the opening, a particularly simple and cost-effective production of the ultrasonic sensor device can be made possible. The opening may be an opening going through the base or not going through.

The main body and / or the flexible bending element can be formed by means of extrusion. This allows a particularly cost-effective production of the body. and / or the flexible bending element. In the event that the main body and / or the flexible bending element can be formed by extrusion, in particular by means of cold extrusion, the base body and / or the flexible bending element can be integrally formed. In this case, the opening can represent an opening which does not pass through the main body. Extrusion molding can be used in a production of the flexible bending element and the Grundköpers of metal, in particular aluminum. In the case that the main body is formed by extrusion molding, the opening in the body can be introduced by the extrusion.

The main body may in particular have a plurality of openings.

The openings of the base body can be made in particular simultaneously.

In a further embodiment, the base body and the piezoelectric element arranged in the opening are encapsulated in order to form the flexible bending element in the opening. A material used here may comprise polymer, in particular liquid-crystal polymer. In a same or subsequent process step, the base body with the bending element and the piezoelectric element can be encapsulated to form a housing of the ultrasonic sensor device. This allows a particularly simple and cost-effective production of the ultrasonic sensor device.

With regard to further advantages and features of the method according to the invention, reference is hereby explicitly made to the explanations in connection with the device according to the invention and the description of the figures.

Drawings and examples

Further advantages and advantageous embodiments of the subject invention are illustrated by the drawings and explained in the following description. It should be noted that the drawings have only descriptive character and are not intended to limit the invention in any way. Show it

1 a schematic cross section through an ultrasonic sensor device according to a first embodiment of the invention;

2 a schematic plan view of the ultrasonic sensor device of 1 ;

3 a schematic cross section through an ultrasonic sensor device according to a second embodiment of the invention;

4 a schematic plan view of the ultrasonic sensor device of 3 ;

5 a schematic plan view of an ultrasonic sensor device according to a third embodiment of the invention;

6 a schematic cross-sectional view of the ultrasonic sensor device of 5 ;

7 a schematic plan view of an ultrasonic sensor device according to a fourth embodiment of the invention;

8th a schematic cross section through an ultrasonic sensor device in 7 ;

9 a schematic plan view of an ultrasonic sensor device according to a fifth embodiment of the invention; and

10 a schematic cross section through the ultrasonic sensor device of 9 ,

1 shows an ultrasonic sensor device 1 for detecting and / or transmitting ultrasound 2 according to a first embodiment of the invention. The ultrasonic sensor device 1 has a plurality of ultrasonic sensor elements, here two ultrasonic sensor elements 3a , b, on. Each ultrasonic sensor element 3a , b has a main body 4 on, which one through the main body 4 through opening 5a , b having a circular cross-section. The basic body 4 the ultrasonic sensor elements 3a , b are integrally formed and are hereinafter referred to by the reference numeral 4 designated. Each ultrasonic sensor element 3a , b further comprises a flexible bending element 6a , b, which in the opening 5a , b arranged and electrically conductive, a disk-shaped piezoelectric element 7a , b, which in the opening 5a , b arranged and with the flexible bending element 6a , b, and a damping element 8a , b on, which in the opening 5a , B is arranged and the piezoelectric element 7a , b covered. The flexible bending elements 5a , B closes the end face a first end portion A of the opening 5a , b, in the main body 4 is formed, and the damping element 8a , B closes the end face a second end portion B of the opening 5a , b. A surface 9 of the basic body 4 and a surface 10 of the flexible bending element 6a , b are flush and just trained, so that the bending element 6a , b the ultrasonic sensor element 3a , b closes to the outside.

A flexible substrate 11 , here a flexible circuit board, is along another outer surface 12 of the basic body 4 arranged adjacent to the damping element 8a , b is. The flexible circuit board 11 does not extend along the damping element 5a , b. An electrically conductive layer 13a , b in the form of a surface metallization extends along a surface 14a , b of the flexible bending element 6a , b, which are adjacent to the piezoelectric element 7a , b is along inner sidewalls 15a , b of the main body 4 and along the surface 12 of the basic body 4 , A bond line 16a , b is with the flexible substrate 11 and a surface of the piezoelectric element 7a , b connected adjacent to the damping element 8a , b is arranged. Anisotropic conductive adhesive 17a , b is between the flexible flexure 6a , b and the piezo element 7a , b and isotropic conductive adhesive 18a , b is between the main body 4 and the flexible substrate 11 added.

The ultrasonic sensor elements 3 wise, as in 2 shown to have a circular cross-section and are arranged in a two-dimensional matrix. For the sake of clarity, only one ultrasonic sensor element is designated by the reference numeral 3 Mistake. The matrix has three rows arranged parallel to one another 20 - 22 on. The first row 20 The matrix has six ultrasonic sensor elements arranged along a line in a direction x 3 on. In the second row 21 of the matrix are along the x direction seven ultrasonic sensor elements 3 arranged, and the third row 22 The matrix has six ultrasonic sensor elements 3 along the direction x. The ultrasonic sensor elements 3 the second row 21 are with respect to the ultrasonic sensor elements 3 the first and third rows 20 . 22 arranged offset by a distance which is equal to the radius of the circular cross-section of the ultrasonic sensor element 3 is. Consequently, the ultrasonic sensor elements are 3 the first and third row 20 . 22 arranged along a common line in a direction y. Surface mount capacitors are in one area 23a , b arranged, which is parallel to the first and third rows 20 . 22 extend the matrix of the ultrasonic sensor elements. The capacitors are used for drift compensation and are parallel to the ultrasonic sensor elements 3 switched and in the plan view in 2 shown in dashed lines.

The ultrasonic sensor elements 3 the first and third row 20 . 22 are configured to transmit the ultrasound, and the ultrasonic sensor elements 3 the second row 21 are set up to receive the ultrasound. Therefore, an object in a sound space of the ultrasonic sensor device 1 time-efficient by means of the ultrasonic sensor device 1 be recorded. It is noted that any number of sensor elements may be used for transmitting and receiving the ultrasound.

In an operation of the ultrasonic sensor device 1 send the ultrasonic sensor elements 3 the first and third row 20 . 22 the ultrasound 2 from the object to be detected in the sound space of the ultrasonic sensor device 1 is reflected. The reflected ultrasound 2 is from the ultrasonic sensor elements 3 the second row 21 receive. Electrical signals are based on the received ultrasound 2 from the ultrasonic sensor elements 3 the second row 21 generates, each of a length expansion change of one of the piezoelectric elements 7a , b are assigned. The deformation in the piezo element 7a , b is indicated by two-ended arrows and is in a receiving operation of the ultrasonic sensor elements 3 by a pressure effect of the ultrasound indicated by means of unilaterally ending arrows 2 on the bending element 6a , b causes. The generated electrical signals are sent to an evaluation unit of the ultrasonic sensor device 1 passed, which detects a positioning of the object in the sound space based on the electrical signals.

Hereinafter, a method for manufacturing the ultrasonic sensor device according to a first embodiment of the invention will be described, in the ultrasonic sensor device 1 in 1 is formed. In a first step of the process becomes the basic body 4 provided as a plate made of alumina ceramic, which is provided with holes which the through holes 5a to form b. Alternatively, the main body 4 as Kaltfließpressteil with the openings going therethrough 5a , b are made. Then the flexible bending elements 6a , b in the opening 5a , b arranged by means of a plastic injection molding method by injection molding. For this purpose, first an inline plasma treatment of the body 4 performed, and the basic body 4 is placed in an injection mold. The openings 5a , b of the main body 4 are partially injected in the injection molding tool with a liquid crystal polymer of specification A950 from Ticonaum. Alternatively, another polymer may be used. This will be the flexible bending element 6a , b in the opening 5a , b formed and with the main body 4 connected.

In a further step of the method, the piezoelectric element becomes 7a , b, which has on a top and a bottom of a previously applied by a Oberflächenmetallisierungstechnik metal layer. In a further step of the method is in the non-electrically conductive body 4 the conductive layer 13 on the surface 14 of the flexible bending element 6a , b, on the sidewalls 15 of the basic body 4 and on the surface 12 of the basic body 4 when Surface metallization applied. The conductive layer 13 can at a base body 4 made of metal. The piezo element 7a , b is then by means of the electrically conductive anisotropic conductive adhesive 17 at the coated top 14 of the flexible bending element 6a , b glued on. The piezo element 7a , b is attached to the flexible bending element 6a , b pressed, and the conductive adhesive 17 is cured. In this way, a contacting of the piezoelectric element 7a , b and the flexible Substates 11 over the conductive layer 13 provided.

In a further step, the isotropic conductive adhesive is used in a screen printing process 18 on the conductive layer 13 on the surface 12 of the basic body 4 applied, and the flexible substrate 11 gets to the body 4 pressed on and cured under pressure. Applying pressure to the flexible substrate 11 and / or the main body 4 can also be omitted.

In a further step, an electrical contact between the underside of the piezoelectric element 7a , b and the flexible substrate 11 accomplished by a bonding wire 16a , b between both elements 7a , b, 11 is attached by means of bonding. A contacting of the underside of the piezoelectric element 7a , b and the flexible substrate 11 by Reibschweißens a conductor to the underside of the piezoelectric element 7a , b and the flexible bending element 11 is also possible.

In a further step, the openings 5a , b automatically filled with polyurethane foam. Alternatively, silicone foam can be used. The foam is cured, causing the damping element 8a , b is formed. This causes a potting of the piezoelectric element 7a , b and the bond wire 16a , b in the opening 5a , b. Following this, the capacitors are in the areas 23a , b on the flexible substrate 11 applied and electrically connected to the ultrasonic sensor elements 3a , b interconnected.

3 and 4 show another sensor device 1 according to a second embodiment of the invention. The ultrasonic sensor device 1 is similar to the ultrasonic sensor device 1 from 1 and 2 educated. However, the main body 4 and the flexible bending element 6a , b made in one piece from aluminum as an extruded part. The main body 4 does not point through the body 4 through openings 5a , b, ie blind holes, on. The flexible bending element 6a , b is outside the opening 5a , b arranged and closes a first end portion A of the opening 5a , B, by the flexible bending element 6a , b the opening 5a , b covered. The bending element 5a , b is formed as a circular membrane with a diameter in a range of about ≥ 4 to about ≤ 5 mm and a thickness in a range of about ≥ 0.2 to about ≤ 0.4 mm. The thin bending membrane 5a , b is circumferentially with the main body 4 connected and has a strong stiffened outer portion. The ultrasonic sensor element 3a , b further comprises compared to the ultrasonic sensor element 3a , b in 1 no conductive layer 13a , b along the surface 14a , b of the flexible bending element 6a , b, along inner sidewalls 15a , b of the main body 4 and along the outer surface 12 of the basic body 4 adjacent to the damping element 8a , b on, because the piezo element 7a , b over the anisotropic conductive adhesive 17a , b directly the electrically conductive base plate 4 and the flexible circuit board 11 the main body 4 directly over the isotropic conductive adhesive 18a , b contacted. A resonant frequency of the ultrasonic sensor elements 3a , b is 50 kHz.

An operation of the ultrasonic sensor device 1 is similar to the operation of the ultrasonic sensor device 1 in the 1 and 2 ,

In a method of manufacturing the sensor device 1 According to a second embodiment of the invention, the base body 4 together with the flexible bending elements 6a , b made by extrusion from an aluminum plate. In this process step, the non-passing openings 5a , b in the main body 4 brought in. The following will be made with reference to the ultrasonic sensor device 1 of the 1 and 2 described method steps that are performed after forming the bending element of polymer.

The 5 and 6 show an ultrasonic sensor device 1 according to a third embodiment of the invention. The ultrasonic sensor elements 3 the ultrasonic sensor device 1 are similar to the ultrasonic sensor elements 3 the ultrasonic sensor device 1 in the 1 and 2 formed, however, have instead of the conductive layer 13 and one bond wire 16a , b two bonding wires between the piezoelectric element and the flexible substrate. Furthermore, the ultrasonic sensor elements 3 the ultrasonic sensor device 1 in three rows 20 - 22 arranged, each having six ultrasonic sensor elements 3 which are arranged equidistantly to one another along a first direction x of the matrix-type arrangement and a second direction y of the matrix-type arrangement, which runs perpendicular to the first direction x. This arrangement is exemplary. The ultrasonic sensor elements 3 can also, in plan view of the main body 4 seen to be circular.

An operation of the ultrasonic sensor device 1 is similar to the operation of the ultrasonic sensor device 1 of the 1 and 2 ,

In a method of manufacturing the ultrasonic sensor device 1 According to a third embodiment of the invention, the base body 4 with the openings 5 provided as a cold extruded part. After that, the piezo elements become 7 automatically applied in an injection mold with surface metallizations applied on both sides and then the alumina ceramic basic body 4 taken in the injection mold. Here are the piezo elements 7 a lateral Umkontaktierung of the surface metallization at its top, which in an assembled state of the ultrasonic sensor device 1 the flexible bending element 6 facing the surface metallization on another top, in the assembled state of the ultrasonic sensor device 1 the damping element 8a is facing. In the field of flexible bending elements 5 becomes the basic body 4 together with the piezo elements 7 molded. Therefore, the piezo elements 7 not with the flexible bending elements 6 bonded. In the same process step, this becomes the basic body 4 enclosing housing sprayed. Following this, the electrical contacting of the further upper side of the piezoelectric elements takes place 7 and the flexible substrate 11 by means of bonding. There are two bonding wires 16 between each of the further surfaces of the piezoelectric elements 7 and the flexible substrate 11 educated. Thereafter, polymer or silicone based material is inserted into the openings 5 introduced, whereby the damping elements 8th be formed after curing of the respective material.

7 and 8th show an ultrasonic sensor device 1 according to a fourth embodiment of the invention. The ultrasonic sensor elements 3a -F of the ultrasonic sensor device 1 are identical to the ultrasonic sensor elements 3a -F of the ultrasonic sensor device 1 in 5 and 6 educated. However, have openings of the ultrasonic sensor elements 3 instead of a circular cross section on a rectangular cross section.

An operation of the ultrasonic sensor device 1 is similar to the operation of the ultrasonic sensor device 1 in 5 and 6 ,

A method of manufacturing the ultrasonic sensor device 1 According to a fourth embodiment of the invention is similar to a method of manufacturing the ultrasonic sensor device 1 in 5 and 6 educated. Here, the cross-sectional shape of the ultrasonic sensor elements 3 due to the used extrusion and injection molding technology particularly easy to produce.

9 and 10 show an ultrasonic sensor device 1 according to a fifth embodiment of the invention. The ultrasonic sensor device 1 is similar to the ultrasonic sensor device 1 in 1 and 2 formed, however, has an additional cover layer 25 on, extending along a surface of the main body 4 and a surface of the polymer-based flexible flexure 5 extends. A surface 26 the cover layer 25 is curved and a thickness of the cover layer 25 decreases continuously towards its exterior.

An operation of the ultrasonic sensor device 1 is similar to the operation of the ultrasonic sensor device 1 in 1 and 2 ,

In the methods for manufacturing the ultrasonic sensor device 1 According to a fifth embodiment of the invention, the method steps of the method are carried out, which with reference to 1 and 2 is described. The cover layer 25 becomes simultaneously with the flexible bending elements 6 formed by encapsulation.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2008/0060439 A1 [0003]

Claims (13)

Ultrasonic sensor element ( 3a -F) for detecting and / or transmitting ultrasound ( 2 ), wherein the ultrasonic sensor element ( 3a -F) comprises: - a basic body ( 4 ), which has an opening ( 5a , b), - a flexible bending element ( 6a , b), which end face a first end portion (A) of the opening ( 5a , b) closing, wherein the flexible bending element ( 6a , b) a polymer, in particular a liquid-crystal polymer, having - a piezoelectric element ( 7a , b), which in the opening ( 5a , b) and with the flexible bending element ( 6a , b) is connected, and - a damping element ( 8a , b), which in the opening ( 5a , b) is arranged and frontally a second end region (B) of the opening ( 5a , b) closes. Ultrasonic sensor device ( 1 ) for detecting and / or transmitting ultrasound ( 2 ), wherein the ultrasonic sensor device ( 1 ) a plurality of ultrasonic sensor elements ( 3a F), wherein each ultrasonic sensor element ( 3a -F) comprises: - a basic body ( 4 ), which has an opening ( 5a , b), - a flexible bending element ( 6a , b), which end face a first end portion (A) of the opening ( 5a , b) closes, - a piezo element ( 7a , b), which in the opening ( 5a , b) and with the flexible bending element ( 6a , b) is connected, and - a damping element ( 8a , b), which in the opening ( 5a , b) is arranged and frontally a second end region (B) of the opening ( 5a , b) closes, wherein the main body ( 4 ) of the ultrasonic sensor elements ( 3a F) the plurality of ultrasonic sensor elements ( 3a -F) are integrally formed. Ultrasonic sensor device ( 1 ) according to claim 2, wherein the flexible bending element ( 6a , b) a polymer, in particular a liquid crystal polymer. Ultrasonic sensor device ( 1 ) according to claim 2, wherein the flexible bending element ( 6a , b) and the basic body ( 4 ) of each ultrasonic sensor element ( 3a F) are integrally formed, wherein a material of the flexible bending element ( 6a , b) and the basic body ( 4 ) in particular metal, metal oxide, and / or metal oxide ceramic has. Ultrasonic sensor device ( 1 ) according to any one of claims 2 to 4, wherein a substrate ( 11 ) along an outer surface ( 9 ) of the basic body ( 4 ) adjacent to the damping element ( 8a , b) is arranged. Ultrasonic sensor device ( 1 ) according to one of claims 2 to 5, wherein the ultrasonic sensor element ( 3a -F) further comprises: - a cover element ( 25 ) extending along an outer surface ( 9 ) of the basic body ( 4 ) adjacent to the bending element ( 6a , b) and an outer top ( 10 ) of the bending element ( 6a , b) of the piezo element ( 7a , b) facing away from, extends. Ultrasonic sensor device ( 1 ) according to one of claims 2 to 6, wherein an outer upper side ( 9 ) of the basic body ( 4 ) adjacent to the flexible bending element ( 6a , b), an outer top ( 10a , b) the flexible bending element ( 6a , b) of the piezo element ( 7a , b) facing away from, and / or an outer top ( 26 ) of the cover element ( 25 ) is formed at least partially curved. Ultrasonic sensor device ( 1 ) according to one of claims 2 to 7, wherein the plurality of ultrasonic sensor elements ( 3a -F) are arranged in a one-dimensional or two-dimensional pattern. Ultrasonic sensor device ( 1 ) according to one of claims 2 to 8, wherein the plurality of ultrasonic sensor elements ( 3a -F) for transmitting and / or receiving the ultrasound ( 2 ) are set up. Ultrasonic sensor device ( 1 ) according to one of claims 2 to 9, wherein the ultrasonic sensor device ( 1 ) is received in a parking device or in a maneuver assistance system of a vehicle. Method for producing an ultrasonic sensor device ( 1 ) for detecting and / or transmitting ultrasound ( 2 ), wherein the ultrasonic sensor device ( 1 ) a plurality of ultrasonic sensor elements ( 3a F), wherein producing an ultrasonic sensor element ( 3a -F) comprising: - providing a basic body ( 4 ), which has an opening ( 5a , b), - closing a first end region of the opening on the front side ( 5a , b) by a flexible bending element ( 6a , b), - arranging a piezoelectric element ( 7a , b) in the opening ( 5a , b), - Connecting the flexible bending element together ( 6a , b) and of the piezo element ( 7a , b), - arranging a damping element ( 8a , b) in the opening ( 5a , b), and - closing a second end region of the opening at the front ( 5a , b) by the damping element ( 8a , b), wherein the basic bodies ( 4 ) of the ultrasonic sensor elements ( 3a F) the plurality of ultrasonic sensor elements ( 3a -F) are integrally formed. The method of claim 11, wherein providing the body ( 4 ) Inserting the opening into the basic body ( 4 ), which is introduced in particular by means of drilling, eroding or extrusion, in particular cold extrusion. A method according to claim 11 or 12, wherein the base body ( 4 ) and in the opening ( 5a , b) arranged piezoelement ( 7a , b) are overmoulded.

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