Ultrasonic array sensor

Abstract

The invention relates to an ultrasonic array sensor (100) with at least two ultrasonic membrane elements (101) for transmitting and receiving ultrasonic signals and a housing (103) with a cover plate (105), wherein: the cover plate (105) is arranged on a transmitting-receiving side of the ultrasonic array sensor (100); the cover plate (105) contacts and completely covers the at least two ultrasonic membrane elements (101); the cover plate (105) is designed to effect a transfer of transmitted and / or received ultrasonic signals from and / or to the ultrasonic membrane elements (101); and an outer surface (107) of the cover plate (105) is designed as a flat surface.

Description

[0001] Description

[0002] title

[0003] Ultrasonic array sensor

[0004] The invention relates to an ultrasonic array sensor. The invention particularly relates to an ultrasonic array sensor for vehicle construction.

[0005] State of the art

[0006] Ultrasonic sensors are used in automotive engineering and other industrial applications for distance determination and environmental sensing. State-of-the-art ultrasonic sensors operate according to the pulse-echo principle, in which a time-of-flight measurement is performed between the transmission and reception of ultrasonic pulses. For increased sensor performance, ultrasonic array sensors are available, each of which comprises a plurality of different ultrasonic membrane elements for individual pulse-echo measurements.

[0007] It is an object of the invention to provide an ultrasonic array sensor.

[0008] This problem is solved by the ultrasonic array sensor of the independent claim. Advantageous embodiments are the subject of the subordinate claims.

[0009] According to one aspect of the invention, an ultrasonic array sensor is provided with at least two ultrasonic membrane elements for transmitting and receiving ultrasonic signals and a housing with a cover plate, wherein the cover plate is arranged on a transmitting / receiving side of the ultrasonic array sensor, wherein the cover plate contacts and completely covers the at least two ultrasonic membrane elements, wherein the cover plate is configured to effect a transmission of transmitted and / or received ultrasonic signals from and / or to the ultrasonic membrane elements, and wherein an outer surface of the cover plate is designed as a flat surface.

[0010] This provides the technical advantage of providing an improved ultrasonic array sensor with a plurality of ultrasonic membrane elements. The flat surface of the cover plate allows for uninterrupted emission of the ultrasonic signals from the ultrasonic membrane elements. However, elevations and / or depressions in a non-flat cover plate lead to reflection effects of the emitted or received ultrasonic signals. Such reflections of the ultrasonic signals lead to interference effects of the ultrasonic signals, in particular to undesirable changes in the time signal and in the directivity of the sound emission or reception, and thus ultimately to disturbed or incorrect measurements or measurement results of the ultrasonic array sensor.

[0011] According to one embodiment, the cover plate has a higher rigidity in the regions contacting the ultrasonic membrane elements than in the regions between the at least two ultrasonic membrane elements.

[0012] This provides the technical advantage that the reduced rigidity of the cover plate in the areas between the ultrasonic membrane elements reduces sound transmission in the cover plate between the ultrasonic membrane elements. This prevents ultrasonic signals from being transmitted via the cover plate between the ultrasonic membrane elements, thereby interfering with the measurements of the ultrasonic membrane elements. Despite the shared cover plate, the ultrasonic membrane elements can be operated as independent sensor elements without interference from the other ultrasonic membrane elements.

[0013] According to one embodiment, the cover plate comprises a fiber composite material, wherein the cover plate has a higher fiber density of a fiber structure of the fiber composite material in the areas contacting the ultrasonic membrane elements than in the areas between the ultrasonic membrane elements.

[0014] This provides the technical advantage of allowing for simple production of the cover plate. The lower fiber density in the areas between the ultrasonic membrane elements reduces the stiffness in these regions. This reduces sound transmission in the cover plate between the areas adjacent to the ultrasonic membrane elements. This allows for individualization of at least two ultrasonic membrane elements, allowing each ultrasonic membrane element to be operated independently of the other element.

[0015] According to one embodiment, the fiber composite comprises a multi-layer fiber structure, wherein in the regions contacting the ultrasonic membrane elements, a number of layers of the multi-layer fiber structure is greater than in the regions between the ultrasonic membrane elements.

[0016] This allows for the technical advantage of achieving high flexibility of the cover plate in the areas between the ultrasonic membrane elements, resulting in poor sound transmission within the cover plate between the ultrasonic membrane elements. Due to the smaller number of layers of the fiber structure, the stiffness of the cover plate is reduced in the areas between the ultrasonic membrane elements.

[0017] According to one embodiment, the layers of the multi-layer fiber structure are formed over the entire thickness of the cover plate.

[0018] This can achieve the technical advantage of achieving high flexibility of the cover plate in the areas between the ultrasonic membrane elements, resulting in poor sound transmission within the cover plate between the ultrasonic membrane elements. To this end, a smaller number of layers of the fiber structure are arranged in the areas between the ultrasonic membrane elements. According to one embodiment, the layers of the multilayer fiber structure in the areas between the ultrasonic membrane elements are arranged over only a portion of the thickness of the cover plate.

[0019] This can achieve the technical advantage of ensuring high flexibility of the cover plate in the areas between the ultrasonic membrane elements and, consequently, poor sound transmission within the cover plate between the ultrasonic membrane elements.

[0020] According to one embodiment, the cover plate has recesses for material tapering in the areas between the ultrasonic membrane elements on an inner surface of the cover plate.

[0021] This can achieve the technical advantage of ensuring high flexibility of the cover plate in the areas between the ultrasonic membrane elements and, consequently, poor sound transmission within the cover plate between the ultrasonic membrane elements.

[0022] According to one embodiment, no fiber structure is formed in the areas between the ultrasonic membrane elements.

[0023] This can achieve the technical advantage of ensuring high flexibility of the cover plate in the areas between the ultrasonic membrane elements and, consequently, poor sound transmission within the cover plate between the ultrasonic membrane elements.

[0024] According to one embodiment, the ultrasonic membrane elements are fixed to the cover plate via an adhesive connection.

[0025] This provides the technical advantage of firmly connecting the ultrasonic membrane elements to the cover plate, ensuring good sound transmission between the ultrasonic membrane elements and the cover plate. According to one embodiment, the ultrasonic membrane elements are connected to the cover plate using a molding process, in particular a resin transfer molding process such as resin transfer molding (RTM) or vacuum-assisted resin transfer molding (VARTM).

[0026] This offers the technical advantage of simplified manufacturing. The ultrasonic membrane elements are integrated into the cover plate during the production of the fiber composite material in the same molding process. This ensures a firm connection to the cover plate and good sound transmission.

[0027] According to one embodiment, the fiber structure is formed as a woven fabric, scrim, warp-knitted fabric, braided fabric or nonwoven fabric.

[0028] This allows the technical advantage of providing a lightweight and high-performance fiber structure.

[0029] According to one embodiment, a metal layer is arranged on the outer surface of the cover plate.

[0030] This offers the technical advantage of increasing the sensor's resilience. Especially for use in automotive construction, the metal layer allows for improved paintability of the sensor. This allows for better integration of the sensor into a vehicle body. Furthermore, shielding against electromagnetic interference can be improved.

[0031] According to one embodiment, the cover plate is fixed to the housing with an adhesive bond.

[0032] This achieves the technical advantage of securely attaching the cover plate to the housing. This fixation enables optimal sound transmission from the ultrasonic membrane elements via the cover plate to the sensor's surroundings. Embodiments of the invention are explained with reference to the following drawings. The drawings show:

[0033] Fig. 1 is a schematic exploded view of a prior art ultrasonic array sensor;

[0034] Fig. 2 is a schematic side sectional view of an ultrasonic array sensor according to an embodiment;

[0035] Fig. 3 is a further schematic side sectional view of an ultrasonic array sensor according to a further embodiment;

[0036] Fig. 4 is a further schematic side sectional view of an ultrasonic array sensor according to a further embodiment;

[0037] Fig. 5 is a further schematic side sectional view of an ultrasonic array sensor according to a further embodiment;

[0038] Fig. 6 is a further schematic side sectional view of an ultrasonic array sensor according to a further embodiment;

[0039] Fig. 7 is a further schematic side sectional view of an ultrasonic array sensor according to a further embodiment;

[0040] Fig. 8 is a further schematic side sectional view of an ultrasonic array sensor according to a further embodiment;

[0041] Fig. 9 is a further schematic side sectional view of an ultrasonic array sensor according to another embodiment;

[0042] Fig. 10 is a further schematic side sectional view of an ultrasonic array sensor according to another embodiment;

[0043] Fig. 11 is a further schematic side sectional view of an ultrasonic array sensor according to a further embodiment; Fig. 12 is a further schematic side sectional view of an ultrasonic array sensor according to a further embodiment;

[0044] Fig. 13 is a schematic plan view of an ultrasonic array sensor according to an embodiment;

[0045] Fig. 14 is a further schematic plan view of an ultrasonic array sensor according to another embodiment; and

[0046] Fig. 15 is a further schematic plan view of an ultrasonic array sensor according to another embodiment.

[0047] Fig. 1 shows a schematic exploded view of a prior art ultrasonic array sensor 100A.

[0048] Fig. 1 shows an ultrasonic array sensor 100A known from the prior art. The ultrasonic array sensor 100A comprises a housing 103A and a cover plate 105A. Four square ultrasonic membrane elements 101A are shown in the cover plate 105A, which are embedded in the cover plate 105A. For this purpose, the cover plate 105A has four square-shaped recesses into which the ultrasonic membrane elements 101A are embedded. The recesses are each designed as funnel-shaped depressions 106A. Due to the funnel-shaped depressions 106A, the cover plate 105A has a characteristic structure. This makes painting the cover plate 105A more difficult and prevents installation of the ultrasonic array sensor 100A, for example, in a vehicle body.In addition, the beveled edge regions of the funnel-shaped depressions 106A represent reflection surfaces for the ultrasonic signals of the ultrasonic membrane elements 101A. The reflection surfaces or the reflections of the ultrasonic signals result in poorer signal quality and poorer directivity of the sound radiation or sound reception, and thus impair the performance of the ultrasonic array sensor 100A.

[0049] Fig. 2 shows a schematic side sectional view of an ultrasonic array sensor 100 according to one embodiment. According to the invention, the ultrasonic array sensor 100 comprises at least two ultrasonic membrane elements 101, a housing 103, and a cover plate 105. The cover plate 105 is fixed to the housing 103 in a transmit / receive side 106 of the ultrasonic array sensor 100. The cover plate 105 contacts the ultrasonic membrane elements 101. The ultrasonic array sensor 100 further comprises an internal MEMS sensor structure 117, which is designed, for example, as a piezo element and is configured to generate or detect ultrasonic signals.

[0050] According to the invention, the cover plate 105 extends over the entire transmit / receive side 106 of the ultrasonic array sensor 100. The cover plate 105 has a flat outer surface 107. In contrast to the prior art shown in Fig. 1, the outer surface 107 has no recesses or funnel-shaped depressions, but is designed as a structureless, flat surface. Designing it as a flat surface facilitates the paintability of the cover plate 105, and the ultrasonic array sensor 100 can be unobtrusively integrated into a vehicle body. Furthermore, the cover plate 105 has no structuring and, associated with it, no reflective surfaces, thus enabling uninterrupted transmission and reception of ultrasonic signals.

[0051] According to one embodiment, the cover plate 105 has a higher rigidity in regions 109 where the cover plate 105 contacts the ultrasonic membrane elements 101 than in regions 111 between the ultrasonic membrane elements 101. Due to the lower rigidity in the regions 111 between the ultrasonic membrane elements 101, the sound conductivity of the cover plate 105 in these regions 111 is reduced. This can prevent or at least reduce the transmission of ultrasonic signals via the cover plate 105 between the at least two ultrasonic membrane elements 101. This can prevent signal contamination of the individual ultrasonic signals transmitted or received by the ultrasonic membrane elements 101.With the common cover plate 105, which contacts and covers the various ultrasonic membrane elements 101, each individual ultrasonic membrane element 101 can be operated independently of the other ultrasonic membrane elements 101. Due to the lower rigidity of the areas 111 between the ultrasonic membrane elements 101, the signal contamination of the ultrasonic signals of one ultrasonic membrane element 101 by ultrasonic signals from another ultrasonic membrane element 101 can be reduced to one third.

[0052] According to the embodiment shown in Fig. 2, the increased rigidity in the regions 109 contacting the ultrasonic membrane elements 101 is achieved by a fiber structure 115 of a fiber composite material of the cover plate 105. The fiber structure 115 is designed as a multi-layer fiber structure 115 and comprises several layers of the fiber material. The layers can be designed, for example, as woven, non-crimp, warp-knit, braided, or nonwoven fabrics. The fiber material can, for example, comprise glass fiber, carbon fiber, aramid fiber, basalt fiber, UHMWPE fibers (ultra-high molecular weight polyethylene), LCP fibers (liquid crystal polymer), or flax fibers. The fiber composite material of the cover plate 105 can thus be designed as a plastic fiber composite in which the fiber structure 115 is integrated into a synthetic resin material.The cover plate 105 can be manufactured, for example, by a molding or casting process, optionally by a resin transform molding (RTM) process or a vacuum assisted resin transfer molding (VARTM) process.

[0053] In the embodiment shown, a fiber structure 115 is also formed in the edge regions 113 of the cover plate 105, where the cover plate 105 adjoins the housing 103. In the embodiment shown, no fiber structure 115 is formed in the regions 111 between the ultrasonic membrane elements 101 and in the regions 112 between the ultrasonic membrane elements 101 and the edge regions 113. Due to the missing fiber structure 115 in the regions 111, 112, these have reduced rigidity compared to the regions 109, 113 and thus a reduced sound conductivity. Furthermore, due to the reduced rigidity in the regions 112, sound transmission of the ultrasonic signals of the ultrasonic membrane elements 101 via the cover plate 105 from the regions 109 into the edge regions 113 and thus into the housing 103 can be avoided or reduced.In the embodiment shown, the fiber structures 115 are formed in the regions 109, 113 over an entire thickness 129 of the cover plate 105.

[0054] In the embodiment shown, the ultrasonic membrane elements 101 are connected to the inner MEMS sensor structure 117 via an adhesive bond 121. The cover plate 105 is connected to the housing 103 via another adhesive bond 119.

[0055] In the embodiment shown, the ultrasonic membrane elements 101 are at least partially integrated into the cover plate 105. For this purpose, the ultrasonic membrane elements 101 can be processed in a common mold using the above-mentioned injection molding or forming process and thus at least partially integrated into the cover plate 105 and connected thereto.

[0056] The ultrasonic membrane elements 101 can be made of metal.

[0057] Fig. 3 shows a further schematic side sectional view of an ultrasonic array sensor 100 according to a further embodiment.

[0058] The embodiment in Fig. 3 is based on the embodiment in Fig. 2. In contrast to the embodiment in Fig. 2, the embodiment in Fig. 3 has recesses 123 on an inner surface 108 of the cover plate 105 in the regions 111, 112. The recesses 123 taper the cover plate 105 and, associated with this, reduce the rigidity of the cover plate 105 in the regions 111, 112. The sound transmission in the regions 111, 112 within the cover plate 105 can be further reduced by the recesses 123.

[0059] Fig. 4 shows a further schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0060] The embodiment shown in Fig. 4 is based on the embodiment in Fig. 1 . In contrast, the embodiment shown in Fig. 4 has a metal layer 125 on the outer surface 107. The metal layer 125 further improves the paintability of the cover plate 105 and, associated with it, the integrability of the ultrasonic array sensor 100 into a vehicle body. In addition, the shielding against electromagnetic interference can be improved. The metal layer 125 can be applied to the cover plate 105, for example, by a metal deposition process, metal plating, thermal evaporation, or a sputtering process. Alternatively, integration of a metal foil using the resin transform molding (RTM) process is possible. The thickness of the metal layer 125 can be in the nanometer or micrometer range.

[0061] Fig. 5 shows a further schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0062] The embodiment in Fig. 5 is based on the embodiment in Fig. 1. Deviating from this, in the embodiment shown in Fig. 5 the ultrasonic membrane elements 101 are connected to the cover plate 105 via an adhesive connection 127 on the inner surface 108.

[0063] Fig. 6 shows a further schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0064] The embodiment in Fig. 6 is a combination of the embodiments in Fig. 3 and Fig. 5.

[0065] Fig. 7 shows a further schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0066] The embodiment shown in Fig. 7 is based on the embodiment in Fig. 1. In contrast, the embodiment in Fig. 7 also has a fiber structure 115 in the regions 111, 112. However, in the embodiment shown, the fiber structure 115 in the regions 111, 112 is not formed over the entire thickness 129 of the cover plate 105. The fiber structure 115 in the regions 111, 112, however, is limited to an area adjacent to the outer surface 107 of the cover plate 105 and, in the embodiment shown, amounts to only half the thickness 129 of the cover plate 105.

[0067] Fig. 8 shows a further schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0068] The embodiment in Fig. 8 is a combination of the embodiments in Fig. 5 and Fig. 7.

[0069] Fig. 9 shows a further schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0070] Fig. 9 is based on the embodiment in Fig. 1 . In contrast, in the embodiment shown, the cover plate 105 has a fiber structure 115 in the regions 111, 112. The fiber structure 115 in the regions 111, 112 extends over the entire thickness 129 of the cover plate 105. However, the multi-layer fiber structure 115 has a smaller number of layers of fiber material in the regions 111, 112 than in the regions 109, 113, in which the stiffness of the cover plate 105 is increased by the fiber composite compared to the stiffness in the regions 111, 112.

[0071] Fig. 10 shows another schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0072] The embodiment in Fig. 10 is based on a combination of the embodiments in Figures 6 and 7.

[0073] Fig. 11 shows another schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0074] Fig. 11 is based on the embodiment in Fig. 10. In the embodiment shown, the fiber structure 115 has a reduced number of layers of fiber material in the regions 111, 112. Due to the reduced number of layers, the stiffness of the regions 111, 112 can be further reduced compared to the regions 109, 113 of the cover plate 105. This further reduces sound conductivity between the regions 109 or between the regions 109 and 113, which means that the individual ultrasonic membrane elements 101 can be operated individually and without interference from one another.

[0075] Fig. 12 shows another schematic side sectional view of an ultrasonic array sensor 100 according to another embodiment.

[0076] The embodiment shown is based on the embodiment in Fig. 2. Unlike the embodiments in Figs. 2 to 11, the cover plate 105 has an edge projection 131. The edge projection 131 is arranged in a designated edge recess 133 of the housing. The edge projection 131 enables a connection to the housing outside the area of ​​the outer surface 107. This is advantageous for a uniform design of the outer surface 107, e.g., during painting, and enables better sealing against moisture.

[0077] Fig. 13 shows a schematic top view of an ultrasonic array sensor 100 according to one embodiment.

[0078] The embodiment shown is based on the embodiment in Fig. 1. In the embodiment shown, the ultrasonic array sensor 100 has four square-shaped ultrasonic membrane elements 101. The regions 109 of the cover plate 105 with fiber structure 115 also have square shapes corresponding to the shapes of the ultrasonic membrane elements 101. In the regions 111 between the ultrasonic membrane elements 101 and in the regions 112 between the ultrasonic membrane elements 101 and the edge regions 113 of the cover plate 105, no fiber structure 115 is formed. In the embodiment shown, the regions 111, 112 are formed as a square frame around the regions 109. The edge regions 113 also have a fiber structure 115, corresponding to the embodiment in Fig. 1.

[0079] Fig. 14 shows a further schematic plan view of an ultrasonic array sensor 100 according to another embodiment. The embodiment in Fig. 13 is based on the embodiment in Fig. 13. Unlike the embodiment in Fig. 13, the regions 111, 112 between the ultrasonic membrane elements 101 and the edge regions 113 are not square and frame-shaped, but rather form a square matrix in which the regions 109 are embedded. As in Fig. 13, the regions 111, 112 also do not have a fiber structure 115.

[0080] Fig. 15 shows a further schematic plan view of an ultrasonic array sensor 100 according to another embodiment.

[0081] In the embodiment shown, the entire cover plate 105 has a fiber structure 115. Only in the regions 109 that directly contact the square ultrasonic membrane elements 101, compared to the edge regions 113 or the regions 111 between the ultrasonic membrane elements 101, is an increased fiber density formed, which is indicated by the increased hatching in the regions 109. Due to the increased fiber density, which can be achieved, for example, by a higher number of layers of the multi-layer fiber structure 115, the regions 109 have a higher rigidity than other regions of the cover plate 105.

[0082] Features of the embodiments of the ultrasonic array sensor 100 according to the invention described in Figures 2 to 15 can be combined as desired, deviating from the embodiments shown. Furthermore, the number and / or shape and / or placement of the ultrasonic membrane elements 101 can differ from the embodiments shown.

Claims

Claims 1. Ultrasonic array sensor (100) with at least two ultrasonic membrane elements (101) for transmitting and receiving ultrasonic signals and a housing (103) with a cover plate (105), wherein the cover plate (105) is arranged on a transmit-receive side of the ultrasonic array sensor (100), wherein the cover plate (105) contacts and completely covers the at least two ultrasonic membrane elements (101), wherein the cover plate (105) is configured to effect transmission of transmitted and / or received ultrasonic signals from and / or to the ultrasonic membrane elements (101), and wherein an outer surface (107) of the cover plate (105) is designed as a planar surface.

2. Ultrasound array sensor (100) according to claim 1, wherein the cover plate (105) has a higher stiffness in the areas (109) contacting the ultrasound membrane elements (101) than in areas (111) between the at least two ultrasound membrane elements (101).

3. Ultrasonic array sensor (100) according to one of the preceding claims, wherein the cover plate (105) comprises a fiber composite material, and wherein the cover plate (105) has a higher fiber density of a fiber structure (115) of the fiber composite material in the areas (109) contacting the ultrasonic membrane elements (101) than in the areas (111) between the ultrasonic membrane elements (101).

4. Ultrasonic array sensor (100) according to one of the preceding claims, wherein the fiber composite material comprises a multilayer fiber structure (115), and wherein in the areas (109) contacting the ultrasonic membrane elements (101) a number of layers of the multilayer fiber structure (115) is larger than in the regions (111) between the ultrasonic membrane elements (101). Ultrasonic array sensor (100) according to claim 4, wherein the layers of the multilayer fiber structure (115) are formed over the entire thickness (129) of the cover plate (105). Ultrasonic array sensor (100) according to claim 4, wherein the layers of the multilayer fiber structure (115) in the regions (111) between the ultrasonic membrane elements (101) are arranged only over a portion of the thickness (129) of the cover plate (105). Ultrasonic array sensor (100) according to any one of the preceding claims, wherein the cover plate (105) has recesses (123) for material tapering on an inner surface (108) of the cover plate (105) in the regions (111) between the ultrasonic membrane elements (101). Ultrasound array sensor (100) according to one of the preceding claims 3 to 7, wherein no fiber structure (115) is formed in the areas (111) between the ultrasound membrane elements (101).Ultrasonic array sensor (100) according to any one of the preceding claims, wherein the ultrasonic membrane elements (101) are fixed to the cover plate via an adhesive bond (127). Ultrasonic array sensor (100) according to any one of the preceding claims, wherein the ultrasonic membrane elements (101) are connected to the cover plate (105) via a forming process, in particular a resin transfer molding (RTM) process. Ultrasonic array sensor (100) according to any one of the preceding claims, wherein the fiber structure (115) is designed as a woven, non-woven, knitted, braided, or braided fabric. Ultrasonic array sensor (100) according to one of the preceding claims, wherein a metal layer (125) is arranged on the outer surface (107) of the cover plate (105).

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