DE102020202544A1 - Ultrasonic sensor of a motor vehicle - Google Patents

Abstract

The invention relates to an ultrasonic sensor (8) of a motor vehicle (2), having a housing (10) to which a number of conductor tracks (30) are connected, with which a microphone (38) is electrically contacted.

Description

The invention relates to an ultrasonic sensor of a motor vehicle.

Motor vehicles usually have a number of ultrasonic sensors. These are used, for example, to record a user gesture or to determine a distance between the motor vehicle and a further object, in particular if these are used as components of a distance sensor of a parking system. Each ultrasonic sensor has a transmitter with a loudspeaker that includes a membrane. The membrane is attached to a permanent magnet which is arranged inside an electrical coil. By applying an electrical alternating voltage to the coil, the permanent magnet is moved in the coil, thus stimulating the membrane to emit sound waves.

If the ultrasonic waves are reflected and / or scattered on an object, they are recorded by means of a microphone of the ultrasonic sensor, which is designed according to the same principle as the transmitter. In other words, the microphone also has a membrane, a permanent magnet and an electrical coil. In a further development, the receiver and the microphone are formed by means of the same structural unit, which is thus operated alternately as a transmitter and microphone.

To simplify assembly, the transmitter and / or the microphone is usually arranged on a printed circuit board and fastened there, for example, by means of SMD technology. Further electrical / electronic components are usually arranged on the circuit board, by means of which the signals detected by the microphone are evaluated. Thus, a signal path between the microphone and the unit evaluating the microphone signals is comparatively short, which is why a signal quality is increased.

To protect against the effects of the weather, the receiver and / or the microphone are usually arranged within a housing. It is necessary to design the housing to be permeable to the ultrasonic waves. As a result, a choice of materials for the housing is limited. As an alternative to this, the housing has a hole through which an exit or one of the ultrasonic waves into the housing is made possible. It is necessary here to arrange the microphone in a specific position with respect to the hole so that the ultrasonic waves detected by the microphone are not falsified due to diffraction or other effects. As a result, when assembling the circuit board in the housing and when assembling the microphone on the circuit board, it is necessary to select comparatively small manufacturing tolerances, which makes manufacturing more difficult and increases manufacturing costs. The printed circuit board is also usually positioned by means of corresponding holding elements which are arranged in the interior of the housing, which in turn increases the production costs. The installation space required is also increased in this way.

The invention is based on the object of specifying a particularly suitable ultrasonic sensor of a motor vehicle, production being advantageously simplified and a required installation space being expediently reduced.

According to the invention, this object is achieved by the features of claim 1. Advantageous further developments and refinements are the subject of the subclaims.

The ultrasonic sensor is part of a motor vehicle. The ultrasonic sensor is suitable, expediently provided and set up for this purpose. The motor vehicle is in particular a land-based motor vehicle and expediently freely positionable on a roadway or the like in the west. In other words, the motor vehicle is preferably not a rail-guided motor vehicle. The motor vehicle is, for example, a commercial vehicle such as a truck or a bus. However, the motor vehicle is particularly preferably a passenger car.

The ultrasonic sensor has a housing which is preferably made from a plastic. In particular, the housing is designed at least partially as a plastic injection-molded part. The housing preferably comprises a pot-like body which is closed by means of a cover. It is thus possible to place different components within the housing. In particular, in the assembled state, the cover is connected to the body, for example in a materially bonded manner. Suitably the cover and the body are welded together. This prevents foreign particles from entering the housing. The components of the ultrasonic sensor arranged within the housing are thus protected from environmental influences by means of the housing.

On the outside of the housing, for example, receptacles for fastening to other components of the motor vehicle, such as a body, are connected. Assembly of the ultrasonic sensor is thus made easier. A plug is preferably introduced into the housing. As a result, a signaling connection between the components arranged in the housing and other components of the motor vehicle is made possible. It is also possible to supply the components arranged therein with electrical energy via the plug.

The ultrasonic sensor also has a microphone. The microphone includes, in particular, a membrane that is used to detect ultrasonic waves. Furthermore, the microphone has a connection at which an electrical signal is applied as a function of the sound waves detected with the membrane. It is possible, for example, to use the microphone to record sound waves with different frequencies. At least, however, it is possible to use the microphone to record ultrasonic waves, that is to say in particular sound waves whose frequency is greater than 25 kHz. The microphone is expediently constructed using microsystem technology and is therefore a so-called MEMS microphone. As a result, the installation space required is reduced.

The ultrasonic sensor also has a number of conductor tracks with which the microphone is electrically contacted. In particular, the microphone is soldered to the conductor tracks. As a result, the microphone is electrically contacted with at least two conductor tracks. It is thus possible to energize the microphone by means of the conductor tracks and / or to feed the signals generated by means of the microphone to further components. In this case, at least one electrical component, such as a resistor, a coil and / or a capacitor, and / or an electronic component, such as a microprocessor, is preferably electrically contacted with the conductor track, so that these components can be used to process the data recorded or recorded by the microphone. generated signals takes place. For example, there are further conductor tracks that are not electrically contacted with the microphone. However, they are preferably electrically contacted with any electrical / electronic components arranged in the housing.

The conductor tracks are connected to the housing. Thus, the conductor tracks are already positioned with respect to the housing, and therefore also the microphone connected to the conductor tracks. Consequently, the position of the microphone with respect to the housing is fixed due to the conductor tracks. Thus, the microphone is always in the desired position, which is why production is simplified. In other words, the microphone is aligned by means of the conductor tracks. In particular, the microphone is connected directly to the conductor tracks, and the conductor tracks are connected directly to the housing. No additional components are therefore required, which further reduces manufacturing costs. The installation space required is also reduced.

The ultrasonic sensor is used, for example, to detect a gesture that is carried out by a user. In particular, direct mechanical contact between the ultrasonic sensor and the person performing the gesture is not required here. As a gesture, for example, performing a specific movement is used, with no direct mechanical contact being present. Alternatively, the user wiping over a surface is used as a corresponding gesture. For example, depending on the detected gesture, a request to perform a function of the motor vehicle is output, for example the requests to actuate an electromotive adjusting device, such as actuating a lock, an electromotive door adjustment or an electromotive window regulator adjustment.

In an alternative to this, the ultrasonic sensor is part of a distance sensor, the distance sensor expediently being part of a parking system. Thus, when maneuvering the motor vehicle, any objects that are in the vicinity of the motor vehicle are detected by means of the ultrasonic sensor. Moving the motor vehicle towards these objects can thus be avoided.

In one embodiment, the conductor tracks and the housing, preferably any body of the housing, are designed as a common structural unit, namely as a molded interconnect device (MID). In other words, the housing and the conductor tracks are designed as a three-dimensional electronic assembly. The conductor tracks are each a stamped and bent part, for example, to which the housing is connected. In particular, the housing is created using a plastic injection molding process that is partially injected around the conductor tracks. The conductor tracks are thus connected to the housing, in particular in a non-detachable manner. The conductor tracks are suitably at least partially embedded in the housing and thus completely surrounded by it. As a result, stability is increased. In this way, the position of the conductor tracks with respect to the housing and consequently also of the microphone with respect to the housing is fixedly predetermined, so that the functioning of the ultrasonic sensor is improved. It is also possible here to arrange and shape the conductor tracks in accordance with the prevailing geometry, so that space requirements are reduced.

In a further alternative, the conductor tracks are provided by means of a circuit board which in particular has a base body which is made, for example, from a glass fiber reinforced epoxy resin. The conductor tracks in particular are connected to this. The circuit board itself is mechanically connected directly to the housing, preferably permanently. In this case, the printed circuit board expediently rests on the housing over its entire surface, for example a base of the body. Thus, the position of the conductor tracks with respect to the housing is fixed. For example, before Attachment of the circuit board to the housing makes electrical contact with the microphone with the conductor tracks and thus expediently attached to the circuit board. In particular, SMD technology is used for this. In summary, a metal layer is provided in particular by means of the printed circuit board, by means of which the conductor tracks are at least partially formed. The metal layer is stabilized with the base body of the circuit board. The base body is expediently partially or flatly metallized, in particular a copper, so that the conductor tracks are provided. Consequently, a layer structure is provided which consists of the housing and the printed circuit board. The conductor tracks are expediently arranged between the housing and the base body of the circuit board. This avoids an electrical short circuit.

For example, the housing and the circuit board are manufactured independently of one another. Particularly preferably, however, the housing is at least partially injected around the circuit board, so that a direct mechanical connection takes place between the circuit board and the housing. Thus, on the one hand, robustness is increased. On the other hand, in this way the housing is adapted to the printed circuit boards during production, which is why functionality is improved. Alternatively, the circuit board is glued, caulked or hot caulked to the housing.

For example, the housing is essentially completely closed and made of a material that is permeable to ultrasonic waves. Here, the microphone is arranged in particular in the interior of the housing. Particularly preferably, however, the housing has a recess which is acoustically coupled to the microphone. A resonance space is preferably created by means of the recess. The resonance chamber is expediently matched to the ultrasonic waves to be detected, so that these ultrasonic waves are amplified or at least not attenuated, that is to say attenuated, by means of the resonance chamber. In particular, the sound waves, which have a frequency with which the ultrasonic sensor is operated, are not attenuated by means of the resonance chamber. Further processing is thus simplified and a signal-to-noise ratio of the signals generated by means of the microphone is improved.

For example, the cutout is continuous, so that the ultrasound waves can enter the housing essentially unhindered through the cutout. In other words, the recess is designed as a hole. Alternatively, the recess is closed on the outside, for example. By means of the cutout, a wall of the housing is thus cut out in particular, so that the wall has a reduced thickness in this area. Consequently, the ultrasonic waves are only slightly attenuated in the area of the recess by means of the housing, which is why processing is simplified. In this case, however, the wall thickness is otherwise comparatively large, so that robustness is increased.

Particularly preferably, however, the recess is open to the outside, so that the penetration of ultrasonic waves can take place essentially unhindered. The recess is designed in particular as a blind hole and thus has a continuous bottom. The microphone is expediently arranged in the recess, preferably on the bottom of the blind hole. Since the recess is open to the outside, the ultrasonic waves thus enter the recess essentially unhindered and hit the microphone there. This means that they can be received essentially undisturbed. In this case, a resonance space is created due to the recess, so that a signal-to-noise ratio is improved. In addition, due to the recess, the microphone is at least partially offset inward, so that when an object strikes the housing or the housing is moved along the object, the microphone is protected by means of the recess. Thus, on the one hand, robustness is increased during operation. On the other hand, assembly is simplified.

In a further alternative, the recess is closed with a base, the base being located on the inside. A substantially unhindered penetration of the ultrasonic waves into the recess from the outside is thus possible. The bottom itself has a hole, the hole being smaller than the recess. A resonance space is thus created by means of the cutout, so that only certain ultrasonic waves that are used in particular for operating the ultrasonic sensor are filtered. These filtered ultrasonic waves can penetrate into the housing by means of the hole. For example, the bottom is made of the same material as the rest of the case. Robustness is thus increased. In an alternative to this, the bottom is formed by means of a further component, such as in particular the circuit board, if any. Thus, a size is reduced.

The microphone itself is positioned inside the housing and is thus at least partially protected by means of the housing. Here, an opening of the microphone, through which the ultrasonic waves penetrate into the microphone in the intended state, or which is at least partially formed by means of a membrane of the microphone, is arranged in alignment with the hole. Thus, the ultrasonic waves guided through the hole strike the opening of the microphone and are essentially undisturbed are thus recorded unhindered. The hole is expediently closed by means of the microphone, which is why the penetration of foreign particles into the housing is avoided, although the detection of the ultrasonic waves is still possible. Since the conductor tracks are connected to the housing, the microphone is already positioned accordingly, i.e. in alignment with the hole. As a result, manufacture is simplified.

For example, the recess is open on the outside. Particularly preferably, however, the housing is at least partially provided on the outside with a protective layer by means of which the recess is covered. Here, for example, the protective layer is applied to the complete housing or only in the area of the recess. Penetration of foreign particles into the recesses and into the housing is thus avoided by means of the protective layer. As a result, damage to the microphone is also prevented. In this case, the protective layer expediently has a comparatively small thickness, which is in particular less than 0.5 mm or 0.1 mm. Thus, the protective layer does not serve to provide mechanical integrity but preferably only to protect against moisture, so that corrosion is avoided. In other words, the penetration of foreign particles is prevented by means of the protective layer, the protective layer essentially not representing an obstacle for the ultrasonic waves and thus being permeable to the ultrasonic waves. The resonance frequency of the recess can also be set comparatively efficiently due to the protective layer. The protective layer is created, for example, by means of a lacquer, so that the housing is lacquered to create the protective layer. Creation is thus simplified. Alternatively, a film is used as a protective layer. For example, there is also an adhesive layer by means of which the film is held on the housing. As an alternative to this, there is, for example, a materially bonded connection of the film to the housing, in particular by means of welding. Robustness is thus increased. If the recess is not present, the protective layer is expediently present, so that the housing is protected.

For example, a transmitter is arranged in the housing, which is designed in particular as a MEMS transmitter using microsystem technology. The transmitter is expediently electrically contacted with at least one of the conductor tracks of the ultrasonic sensor. There is preferably an additional recess which is separate from the recess, if any. In this case, the transmitter is preferably acoustically coupled to the further recess. As an alternative to this, the transmitter is arranged, for example, in the same recess that is also assigned to the microphone, provided that the recess is present.

Particularly preferably, however, the housing is at least partially provided on the outside with a piezoelectric layer. The piezoelectric layer is thus made from a piezoelectric material in which, when this is deformed, an electrical voltage is formed. It is also possible to deform the piezoelectric layer by applying an electrical voltage. The piezoelectric layer here has a comparatively small thickness, which is in particular between 10 μm and 50 μm, and which is, for example, essentially equal to 20 μm, with a deviation of 10 μm, 5 μm or 0 μm in each case, for example. Thus, a need for piezoelectric material is reduced, which reduces manufacturing costs. The piezoelectric layer is provided, for example, by means of a piezoelectric film or a piezoelectric paint. The piezoelectric layer at least partially forms the transmitter. The transmitter suitably has additional electrodes by means of which the piezoelectric layer can be excited. The electrodes are applied, for example, to the piezoelectric layer by means of metallization. The protective layer by means of which the piezoelectric layer is protected is suitably present. The transmitter, expediently the electrodes, are in particular electrically contacted with at least one of the conductor tracks, so that the transmitter is controlled via this. Consequently, due to the connection of the conductor track to the housing, the transmitter is always correctly positioned with respect to the housing, which simplifies manufacture.

The piezoelectric layer is located, for example, directly above the cutout, if any, or offset from it. When an electrical alternating voltage is applied to the piezoelectric layer, expediently by means of the electrodes, it is possible to stimulate the latter to emit sound waves, the excitation taking place in particular in such a way that ultrasonic waves are emitted. In this case, the piezoelectric layer is expediently arranged above the recess so that it serves as a resonance space. In this case, the protective layer, if any, is preferably also excited, so that the ultrasonic waves are also emitted by means of it. The ultrasonic waves are thus emitted over a comparatively large area, which is why any objects can be reliably detected by means of the ultrasonic sensor. In a further alternative, the piezoelectric layer is used to receive ultrasonic waves which, in particular, have a frequency that deviates from the frequency of the ultrasonic waves that are received by means of the microphone.

• 1 schematisch ein Kraftfahrzeug mit einem Ultraschallsensor,
• 2 in einer Schnittdarstellung den Ultraschallsensor, und
• 3 - 10 jeweils in einer Schnittdarstellung ausschnittsweise unterschiedliche Varianten des Ultraschallsensors.

Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. Show in it:

• 1 schematically a motor vehicle with an ultrasonic sensor,
• 2 the ultrasonic sensor in a sectional view, and
• 3 - 10 different variants of the ultrasonic sensor in each case in a sectional view.

Corresponding parts are provided with the same reference symbols in all figures.

In 1 is schematically simplified a motor vehicle 2 shown in the form of a car. The car 2 shows a door 4th on a door handle 6th is connected. The door 4th is driven by means of an adjusting device, not shown, so that the door is activated when activated 4th is pivoted by means of the adjusting device for opening and closing. The adjustment device is activated by detecting a gesture by a user, namely a stroke of the door handle 6th . The gesture is made by means of an ultrasonic sensor 8th of the door handle 6th recorded.

In 2 is a sectional view of the ultrasonic sensor 8th shown. The ultrasonic sensor 8th has a housing 10 on that has a pot-shaped body 12th includes. The body 12th is made from a plastic in a plastic injection molding process. The body 12th is by means of a lid 14th of the housing 10 sealed, made of the same plastic as the body 12th is made in an injection molding process. The cover is in the assembled state 14th with the body 12th welded so that foreign particles are prevented from entering.

In the lid 14th is a plug 16 brought in. The cover shows this 14th a hollow cylindrical connector opening 18th within which several connection pins 20th are arranged, which are designed as a stamped and bent part. The connection pins 20th protrude into the interior of the housing 10 and are there with a circuit board 22nd as well as another printed circuit board 24 electrically contacted, which are parallel to each other and perpendicular to the connection pins 20th are arranged. The two circuit boards 22nd , 24 are constructed in the same way and each have a base body 26th which is made of a glass fiber reinforced epoxy resin.

On the main body 26th is a metal layer on both sides 28 applied by means of metallization, by means of which a number of conductor tracks 30th are formed. The respective metal layer is used for this 28 separated at certain points. The circuit board 22nd lies completely on the floor of the body 12th and covers it completely. Here is the circuit board 22nd by gluing, caulking or caulking to the body 12th attached. An alternative to this is the body 12th by overmolding the circuit board 22nd has been created. Thus are the circuit board 22nd and the case 10 , namely the body 12th mechanically directly and permanently connected to one another.

The bottom of the body 12th has a recess 32 that is open to the outside. On the inside is the recess 32 by means of the circuit board 22nd closed, which thus has a bottom 34 the recess 32 forms. In other words, it is the recess 22nd on the inside with the the bottom 34 forming circuit board 22nd locked. The floor 34 , so the circuit board 22nd , points in the area of the recess 32 a hole 36 on, the extent of which is less than that of the recess 32 is. On the one of the recess 32 opposite side of the hole 36 is on the circuit board 22nd a microphone 38 arranged and on the conductor tracks 30th attached and electrically contacted with these. The microphone 38 is constructed using microsystem technology and is consequently a MEMS microphone. Here is the microphone 38 arranged such that a not shown opening of the microphone 38 with the hole 36 flees. Because of the hole 36 is thus the recess 32 acoustically with the microphone 38 coupled. As the circuit board 22nd inextricably linked to the housing 10 connected, are also the conductor tracks 30th on the housing 10 connected, so that the microphone during production 38 always suitable with regard to the recess 32 and also of the hole 36 is positioned.

At the recess 32 opposite side of the circuit board 22nd , i.e. on the same side as the microphone 38 are on the circuit board 22nd other electrical / electronic components 40 connected, by means of which a further processing of the means of the microphone 38 generated signals takes place. At least some of the electrical / electronic components are for this 40 with the conductor tracks 30th electrically contacted. Also on the other circuit board 24 are such electrical / electronic components 40 connected and by means of the connection pins 20th as well as other contact elements 42 , which are designed as a stamped and bent part, with the circuit board 22nd electrically connected. These electrical / electronic components 40 are on both sides of the further circuit board 24 arranged, which is essentially centered between the circuit board 22nd and the lid 14th is located.

Furthermore, the outside of the housing 10 namely on the bottom of the body 12th , partly an adhesive layer 44 applied, by means of which a piezoelectric layer 46 is held in the form of a piezoelectric film. So the case is 10 on the outside partially with the piezoelectric layer 46 Mistake. This is provided on both sides with electrodes, not shown, which have an opening 48 in the bottom of the body 12th with the circuit board 20th are electrically contacted. This is through the opening 48 a corresponding connection 50 out in the form of a metal part.

The entire external area of the bottom of the body 12th is also with a protective layer 52 provided, which is thus over the piezoelectric layer 46 is led. By means of the protective layer 52 is also the recess 32 covered. The protective layer 52 is in this case provided by means of a lacquer, the lacquer being selected in such a way that it is used when the housing is lacquered 10 not in the recess 32 entry. In summary, the case is 10 partially with the protective layer on the outside 52 Mistake.

The connector is in the assembled state 16 with a corresponding mating connector of the motor vehicle 2 contacted, so that a current is supplied to the electrical / electronic components 40 can be done. Also over some of the connector pins 20th by means of the ultrasonic sensor 8th recorded or other provided data / signals are read out. When operating the ultrasonic sensor 8th is made by means of the electrical / electronic components 40 to the piezoelectric layer 46 an electrical alternating voltage is applied. The frequency here is essentially 25 kHz. As a result, the piezoelectric layer vibrates 46 and therefore also at least partially the protective layer 52 at 25 kHz, so that ultrasonic waves are emitted by means of this. The electrical voltage is only applied for a certain period of time, such as 0.5 seconds.

If the emitted ultrasonic waves are reflected / scattered appropriately on an object, they are returned to the ultrasonic sensor 8th steered and meet there on the protective layer 52 through which the ultrasonic waves can pass essentially unhindered. If this is the protective layer 52 on the case 10 rests, the ultrasonic waves are dampened and absorbed there. However, if the ultrasonic waves enter the recess 32 enter, this acts as a resonance space so that the ultrasonic waves are amplified and passed through the hole 36 guided and consequently by means of the microphone 38 are recorded. The distance between the object and the ultrasonic sensor is determined on the basis of an analysis of the received ultrasonic waves, in particular their shape, and / or on the basis of a transit time comparison between the transmission and the reception of the ultrasonic waves 8th certainly. This is done by means of the electrical / electronic components 40 . The determined distance of the object is via the connector 16 fed into a bus system, not shown, and is thus from other components of the motor vehicle 2 detectable.

In 3 is a modification of the in 2 illustrated ultrasonic sensor 8th shown in detail. In this case the PCB 22nd only on the bottom of the body 12th opposite side with that of the conductor tracks 30th forming metal layer 28 Mistake. The microphone is on these again 38 attached that over the hole 36 with the recess 32 is acoustically coupled that is not changed. In this example the piezoelectric layer is 46 absent, and the protective layer 52 , which in this case is a film, is by means of the adhesive layer 44 on the housing 10 held.

In 4th is a further modification of the ultrasonic sensor 8th shown, with the housing 10 who have favourited the adhesive layer 44 as well as the protective layer 52 are not changed. The circuit board 22nd is again, as in 2 shown on both sides with the metal layer 28 provided, by means of which the conductor tracks 30th are provided. The recess 32 however, it is entirely by means of the printed circuit board 22nd closed, so there is no hole 36 has more. Hence the recess 32 designed as an outwardly open blind hole, the outside with the protective layer 52 is covered. The bottom of the blind hole is made by means of the circuit board 22nd educated. Inside the recess 32 is the microphone 38 arranged and with the conductor tracks 30th electrically contacted. As the microphone 38 in the recess 32 is located, a detection of the ultrasonic waves is improved, but the microphone 38 only by means of the protective layer 52 is protected. As the microphone 38 from one edge of the case 10 is offset away, is still when the housing is approached 10 Damage to other objects during assembly or in the operating state is avoided.

In 5 is a modification of the in 3 illustrated ultrasonic sensor 8th shown. Here, too, is the bottom 34 the recess 32 again by means of the circuit board 22nd educated. In comparison to the variant shown there, there is also the piezoelectric layer 46 present by means of the adhesive layer 44 on the housing 10 is held, and at least partially above the recess 32 runs. The piezoelectric layer 46 is in turn by means of the protective layer 52 , namely the film, covered. Thus, the recess is used 32 also as a resonance space when the ultrasonic waves are emitted. At the in 2 this is not the case. There is a comparatively large area by means of the piezoelectric layer 46 Mistake.

In 6th is a modification of the in 4th shown variant of the ultrasonic sensor 8th shown. The circuit board 22nd who have favourited recess 32 , the microphone 38 as well as their respective arrangement to one another are not changed. However, according to the in 5 shown variant, in the Adhesive layer 44 the piezoelectric layer 46 partially introduced or at least held by means of them, wherein the piezoelectric layer 46 partially above the recess 32 is located. Again is the protective layer 52 available. The recess is therefore also used here 32 as a resonance space for the transmitter, which is partially created by means of the piezoelectric layer 46 is formed.

In 7th is another alternative to the ultrasonic sensor 8th shown. In this case the circuit board is 22nd omitted, however, it is possible that the further circuit board 24 continues to exist. The conductor tracks 30th are still present with the microphone 38 and partly the electrical / electronic components 40 are electrically contacted and hold them mechanically. The conductor tracks 30th are designed as stamped and bent parts and with the housing 10 designed as a common Molded Interconnect Device (MID). In other words, the conductor tracks 30th to create the MID with which the housing 10 molded plastic. Here are the conductor tracks 30th at least partially in the body 12th Forming plastic embedded, so that the conductor tracks 30th inextricably linked to the housing 10 are connected.

The recess 32 is in turn by means of the soil 34 closed the hole 36 having, in this case the bottom 34 by means of the body 12th itself is formed. By means of the conductor tracks 30th is the microphone 38 arranged in such a way that the opening of the microphone, not shown in detail 38 with the hole 36 flees. This is where the microphone is located 38 again inside the case 10 . The housing is on the outside 10 by means of the adhesive layer 44 as well as the protective layer 52 Mistake.

In 8th is another alternative to the ultrasonic sensor 8th which is based on the previous variant. Again, here are the housing 10 as well as the conductor tracks 30th designed as MID. With the conductor tracks 30th are again the electrical / electronic components 40 electrically contacted. In this variant, however, is the recess 32 designed as an outwardly open blind hole, with no connection to the interior of the housing 10 consists. Inside the recess 32 is the microphone 38 arranged with the conductor tracks 30th is electrically contacted by the exit 32 through the housing 10 are guided inside.

In the 9 The variant shown is based on the in 7th embodiment of the ultrasonic sensor shown 8th . However, according to the in 5 variant shown, additionally the piezoelectric layer 46 present, which also by means of the adhesive layer 44 on the housing 10 is held. Again is the microphone 38 inside the case 10 arranged and by means of the hole 46 acoustically with the recess 32 coupled.

In 10 is a last variant of the ultrasonic sensor 8th shown on the in 8th shown execution is based. In comparison, the piezoelectric layer is 46 present, by means of which at least partially the recess 32 is covered, within which the microphone 38 is arranged. Here, too, is the case 10 , namely the body 12th and the conductor tracks 30th designed as a MID, the recess 32 is designed as open to the outside of the blind hole.

In summary, the ultrasonic sensor includes 8th an integrated layered structure of the various elements, namely the housing 12th , the protective layer that acts as a seal 52 and the electrical / electronic components 40 and / or the microphone 38 . Here are the corresponding conductor tracks 30th for contacting the electrical / electronic components 40 and / or the microphone 38 either implemented by means of MID. In an alternative, this is implemented by means of a specially produced layer structure or a layer structure provided by means of gluing or (hot) caulking, which consists of an outer plastic that forms the housing 10 , forms and one of the material of the base body of the circuit board 22nd that is partially or flat metallized with copper. This reduces the number of components and the process is simplified, and alignment is no longer necessary.

In addition, it is with the cavity, namely the recess 32 , the housing 10 a resonance space is created that can be specially tuned to the frequency to be received and thus the sensitivity of the ultrasonic sensor 8th increased for designed use. Furthermore, a piezoelectric film can also be placed in the cover layer 46 can be integrated, which can be used on the one hand for sending and on the other hand for receiving other frequencies.

The invention is not restricted to the exemplary embodiments described above. Rather, other variants of the invention can also be derived therefrom by the person skilled in the art without departing from the subject matter of the invention. In particular, all of the individual features described in connection with the individual exemplary embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

List of reference symbols

2

Motor vehicle

4th

door

6th

Door handle

8th

Ultrasonic sensor

10

casing

12th

body

14th

lid

16

plug

18th

Connector opening

20th

Connection pin

22nd

Circuit board

24

further circuit board

26th

Base body

28

Metal layer

30th

Track

32

Recess

34

floor

36

hole

38

microphone

40

electrical / electronic component

42

Contact element

44

Adhesive layer

46

piezoelectric layer

48

opening

50

connection

52

Protective layer

Claims (8)

Ultrasonic sensor (8) of a motor vehicle (2), with a housing (10) to which a number of conductor tracks (30) are connected, with which a microphone (38) is electrically contacted. Ultrasonic sensor (8) Claim 1 , characterized in that the housing (10) and the conductor tracks (30) are designed as molded interconnect devices. Ultrasonic sensor (8) Claim 1 , characterized in that the conductor tracks (30) are provided by means of a circuit board (22) which is mechanically directly connected to the housing (10) in a non-detachable manner. Ultrasonic sensor (8) according to one of the Claims 1 until 3 , characterized in that the housing (10) has a recess (32) which is acoustically coupled to the microphone (38). Ultrasonic sensor (8) Claim 4 , characterized in that the recess (32) is designed as an outwardly open blind hole, the microphone (38) being arranged in the recess (32). Ultrasonic sensor (8) Claim 4 , characterized in that the recess (32) is closed on the inside with a bottom (34) having a hole (36), the microphone (38) being positioned inside the housing (10), and an opening of the microphone (38) is arranged in alignment with the hole (36). Ultrasonic sensor (8) according to one of the Claims 4 until 6th , characterized in that the housing (10) is provided on the outside with a protective layer (52) by means of which the recess (32) is covered. Ultrasonic sensor (8) according to one of the Claims 1 until 7th , characterized in that the housing (10) is provided on the outside with a piezoelectric layer (46) partially forming a transmitter.

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