Acoustic lens and household appliance therewith

Abstract

The invention relates to an acoustic lens for influencing the radiation pattern of a sound source and a household appliance incorporating such a lens. An acoustic lens (1) comprises an inlet area (4) for the entry of sound waves from a sound source (3), a sound delay area (5) for delaying sound waves, and at least one fracture edge (6) for reflecting sound waves to create an indirect sound source (7). This allows the resulting sound to be defocused particularly effectively, enabling a user to perceive the sound especially well regardless of their specific position.

Description

[0001] The invention relates to an acoustic lens for influencing the radiation behavior of a sound source and a household appliance with an acoustic lens.

[0002] Sound waves emitted by sound sources such as loudspeakers depend on the angle of radiation. Typically, there is a main direction in which the sound is emitted directly and therefore most loudly. The greater the angle to this main direction, the weaker the emitted sound often becomes. Thus, the sound emitted by a sound source varies in volume depending on the position of the receiver.

[0003] The angular dependence can also be frequency-dependent. Low frequencies are often radiated equally in all directions (omnidirectional radiation pattern), while high frequencies exhibit a strong directional dependence. This effect is particularly pronounced when the receiver is located close to the sound source.

[0004] For example, due to structural limitations, it is not always possible to align the sound source directly with the person being sounded. A horn or waveguide can be used for this purpose, but this requires considerable installation space and also increases the directionality of the sound. The goal is to emit sound as uniformly as possible across a wide angular range and in as many frequency ranges as possible.

[0005] US 7 278 513 B2, US 6 095 279 A, ​​EP 3 585 066 A1 and WO 2022 221 582 A1 describe arrangements for influencing sound.

[0006] The object of the invention is to provide an advanced acoustic lens and an advanced household appliance.

[0007] The problem is solved by the acoustic lens according to claim 1 and the household appliance according to the dependent claim. Advantageous embodiments are described in the dependent claims.

[0008] To solve the problem, an acoustic lens is used to influence the radiation pattern of a sound source. The acoustic lens comprises an entrance area for the entry of sound waves from a sound source, a sound delay area to slow down the sound waves, and at least one fracture edge for the reflection of sound waves to create an indirect sound source.

[0009] The invention combines the effects of sound delay and the creation of an indirect sound source. In this way, the sound is emitted with different time delays and diverging from at least two emission regions. A particularly large spatial area can be covered with sound in a largely uniform manner. This is especially true for high frequencies.

[0010] Compared to systems that rely solely on reflections from a housing surface, the frequency range is significantly extended in the solution according to the invention. Furthermore, it provides a means of directing the sound. Compared to systems based on time delay of the sound source, it requires considerably less installation space.

[0011] Sound delay refers to the slowing of sound propagation. For example, sound can be delayed by a path-length refractor or an obstacle array with numerous obstacles that are small compared to the wavelength of the sound. Perforated plates through which the sound passes can also be used for delay. Sound waves can be delayed completely or partially. The sound delay area typically delays the sound waves from the sound source. However, it is possible that sound waves from an indirect sound source are also delayed, either completely or partially. In particular, only a portion of the sound waves from the sound source is delayed. This can be achieved by directing the sound in a desired direction or by increasing the angular range of the sound source. In other words, the sound can be defocused.

[0012] An indirect sound source is a sound source present in addition to the sound source connected to the input area. The indirect sound source is not an active sound source that generates sound itself. Rather, it is a passive sound source that receives sound and re-emits it in a modified form through reflection. Sound from the (main) sound source thus reaches the fracture edge directly or indirectly and is radiated there. In comparison to the sound radiated directly from the sound source, the directional characteristics and / or the timing of the radiation are typically altered. The sound can also be defocused in this way.

[0013] A fracture edge is an edge at which sound waves are refracted. For this purpose, the fracture edge can, for example, be formed as an edge with an angle of approximately 90° or less. From the sound source's perspective, there may be a gap or depression behind the fracture edge. The fracture edge can be straight or curved. The fracture edge typically runs perpendicular to the direction of sound propagation.

[0014] An acoustic lens is an object that selectively influences the directional characteristics, propagation speed, focusing and / or direction of sound waves.

[0015] The incoming sound is preferably emitted (radiated) by a sound source such as a loudspeaker. The entry area can include one or more entry openings. In principle, there can also be multiple entry areas for multiple sound sources.

[0016] The acoustic lens includes, in particular, an exit region for the emission of sound. The exit region is preferably significantly larger than the inlet region. For example, the exit region can be at least 5 times larger, preferably at least 10 times larger, and in one embodiment at least 15 times larger and / or at most 100 times larger than the inlet region. The exit region can be a surface region of the acoustic lens, particularly if the fracture edges are arranged on the surface of the acoustic lens, and / or can include one or more exit openings. The exit region can comprise different exit regions.

[0017] In particular, the acoustic lens is a planar element. A planar element is an element whose extent in the two principal directions of extension is greater by a factor F than its extent in the third direction, which is perpendicular to the principal directions of extension. F is at least 3, in particular at least 5, and preferably at least 8 or at least 10 and / or at most 1000. The plane spanned by the principal directions of extension can be straight or curved.

[0018] In one embodiment, the acoustic lens has a thickness of at most 5 cm, preferably at most 4 cm, particularly preferably at most 3 cm, and in another exemplary embodiment at most 2 cm. In particular, the thickness is more than 0.5 cm or 1 cm. The thickness is the extent of the acoustic lens measured along the short third direction. A particularly compact design is provided.

[0019] In one embodiment, the sound delay region is arranged such that sound waves entering through the entrance region are generated with different delays.

[0020] Different parts of the incoming sound are delayed to varying degrees. This can be achieved, for example, by requiring one part of the wavefront to travel a greater distance than another. This allows different sound components to be generated and emitted at different times. As a result, the sound propagates in a diverging or defocused manner. The sound can be emitted over a particularly wide angular range, minimizing its directivity.

[0021] In a further embodiment, the sound delay area includes several guiding elements for forming sound paths of different lengths.

[0022] By creating sound paths of varying lengths using guide elements, sound delay can be achieved in a small installation space. Guide elements are technically simple and allow for the adjustment of each individual path, even with a large number of sound paths, to precisely control the desired delay. The guide elements typically have different lengths, making it particularly easy to achieve different delays.

[0023] In one embodiment, the guiding elements comprise guiding surfaces extending in the direction of sound and subsequent deflection elements. In this way, the sound can be guided along a guiding element and ultimately deflected by a deflection element in order to be emitted.

[0024] The sound path initially travels along the surface of the acoustic lens, specifically along its principal plane of extension. Guiding surfaces may be present, extending along the plane defined by the first and second principal planes of extension of the acoustic lens. These surfaces may, for example, follow ridges that form a grid. Deflection elements can be arranged to prevent sound from radiating out of the acoustic lens. These elements may be located in the outer region of the acoustic lens and may become smaller with increasing length of the sound path.

[0025] In particular, the sound direction then runs perpendicular to the main plane of extension of the acoustic lens in order to be radiated outwards. Accordingly, deflection elements extending perpendicular to this plane may be present, either alternatively or additionally. These may be located, for example, at the ends of struts and / or be incorporated into parts of a surrounding frame of the acoustic lens. They may be arranged approximately perpendicular to the respective sound path and terminate it. The sound can then radiate out of the acoustic lens.

[0026] In one embodiment, the acoustic lens in the entrance area includes a distribution area where the sound paths originate. In one embodiment, the distribution area is free of guiding elements.

[0027] The different sound paths originate in the distribution area. In other words, the incoming sound is distributed across the different paths within the distribution area. This allows for particularly effective sound delay. For example, the distribution area may have a circular shape and / or the sound paths may originate at different angles relative to a central point within the distribution area. This allows specific portions of the sound to be directed along particular sound paths.

[0028] In one embodiment, the fracture edge is located on a surface of the acoustic lens. Specifically, the fracture edge is located on an outer surface. The fracture edge therefore points outwards. This allows for particularly undisturbed propagation of the sound from the indirect sound source. The surface can consist of several surface elements, which can be spaced apart from one another.

[0029] In one embodiment, the acoustic lens comprises several fracture edges. For example, two, three, four, five, six, seven, or eight fracture edges are present. In another embodiment, approximately ten, twelve, or fifteen fracture edges are present. Fracture edges can be continuous or have breaks. In particular, several fracture edges are arranged one after the other. Different proportions of the sound emitted by the sound source are thus reflected at the respective fracture edges. In this way, a multitude of distributed indirect sound sources can be provided within the surface, which can have different distances from the sound source. At least some fracture edges can be arranged concentrically. Preferably, the fracture edges are curved. Fracture edges can, for example, run in the form of circular paths or arbitrarily curved paths.

[0030] Fracture edges can be arranged so that the sound is reflected substantially or completely in a predetermined direction and / or within a predetermined angular range. For example, the acoustic lens can be located in the lower part of a household appliance, such as a food processor, to emit acoustic signals to a user. In this case, fracture edges can be arranged so that sound is reflected primarily forward. This can, for example, provide particularly effective sound coverage within a 180° angular range where the user is located.

[0031] Since fracture edges reflect particularly high frequencies, the directivity can be significantly reduced even at high frequencies. Depending on the type of sound emitted, this can improve signal strength or speech intelligibility, for example.

[0032] In one embodiment, the acoustic lens has a direct path through which a portion of the sound waves entering through the entrance area are emitted essentially unchanged. A portion of the incoming sound can thus pass through the acoustic lens and be emitted as direct sound. In this way, several (real and virtual) sound sources are utilized. This allows for the uniform sound coverage of a particularly large area.

[0033] The direct path is preferably designed as a free passage between the entry area and an exit area for sound. The direct path can include multiple passages and / or multiple direct paths can be provided for one or more sound sources.

[0034] The direct path can be covered with a protective layer, such as a mesh, fabric, or grid, to prevent objects from entering the acoustic lens and / or the sound source, and / or to create a visually closed shape. The acoustic lens can be partially or completely covered with a protective layer, such as a protective grid or mesh, to prevent objects from entering the acoustic lens and / or the sound source. In particular, a protective layer is stretched over the housing of the acoustic lens.

[0035] In one embodiment, the sound emitted from the direct path corresponds to the sound reflected off a surface below the household appliance.

[0036] In a further embodiment, the acoustic lens is designed as a grid. Preferably, the grid is a planar element. A grid is a perforated element. A grid therefore comprises through openings. The openings extend along the third direction, i.e., through the short extent. This is independent of any protective element that may be present and cover the openings.

[0037] The openings of a grille can be uniformly or irregularly shaped. The openings are separated by grille elements, such as bars. The bars can be straight or curved. Bars can run in a straight or curved direction and / or bars can run at an angle to the straight or curved direction. Bars do not need to be arranged intersecting. Irregular shapes of grille elements or bars can be used. In addition to technically determined shapes, aesthetic considerations can also be taken into account in the design of the grille or bars. In one embodiment, the grille is bounded by a surrounding frame. The openings of the grille can have a smaller or larger area than the grille elements, such as bars, arranged between them.

[0038] To prevent unintentional penetration by fingers or objects, the distances between the webs are preferably no greater than 15 mm, particularly 12 mm, and most preferably 10 mm. Alternatively or additionally, a protective element may be provided.

[0039] In one embodiment, a rib of the grid, in particular each rib, comprises at least one guide surface and a deflection element. In another embodiment, a rib of the grid, in particular each rib, comprises a guide element and a fracture edge.

[0040] Another aspect of the invention is a household appliance with an acoustic lens according to the invention and a sound source coupled to the entrance area of ​​the acoustic lens. In particular, the sound source is a loudspeaker.

[0041] In principle, any household appliance equipped with a sound source and suitable for emitting sound to people can be considered a household appliance. Typically, this refers to an appliance whose sound source is not intended to be placed at or in the user's ear. With such appliances, it is generally desirable to defocus the emitted sound across all frequency ranges to achieve a particularly low directivity. This allows the user to perceive the emitted sound largely independently of their relative position to the appliance.

[0042] The household appliance in question is, for example, a kitchen appliance. Household appliances have sound sources, for example, for notification and / or warning, but also for voice output. Good audibility and, in the case of voice output, good text intelligibility are essential, which can be ensured by the acoustic lens according to the invention.

[0043] In one embodiment, the household appliance is a food processor. The food processor includes, for example, a food preparation container and, in particular, a rotating tool for chopping and / or mixing food in the food preparation container. The food processor includes, in particular, a motor for rotating the tool. The food processor includes, for example, a heating element for heating food in the food preparation container. The food preparation container may be removable. The food processor may be designed for the at least partially automated preparation of food according to an electronically stored recipe. A control unit of the food processor can access a digital recipe and, by a step in the recipe, be prompted to operate the tool and / or the heating element in a manner defined by that step.The food processor can be set up to provide the user with audible guidance and / or instructions using the sound source. For example, the user can be instructed to add a specific quantity of a particular ingredient to the food preparation container and / or to operate the appliance in a defined manner.

[0044] In one embodiment, the household appliance is a cleaning device, such as a cleaning robot. Cleaning devices can issue various acoustic instructions to users, which can be advantageously accomplished through the acoustic lens as described. A cleaning robot is a robot capable of picking up particles. A cleaning robot can clean an area without requiring a user during the cleaning process. The cleaning robot can be a vacuuming robot and / or a mopping robot. A mopping robot has a wiping element, such as a cloth, mop, sponge, or cleaning cloth. The wiping element can absorb water. A mopping robot can have a blower for suctioning dirt and / or be configured so that the wiping element can be moved translationally and / or rotationally relative to the robot's housing to pick up dirt particles.A robotic vacuum cleaner can independently clean an area by vacuuming. The robotic vacuum cleaner has a fan that draws in air. It has a container in which the vacuumed particles are collected. The robotic vacuum cleaner has at least one filter that separates the dust from the air it draws in, which is laden with particles. The cleaned air is then blown out of the robotic vacuum cleaner.

[0045] It is not necessary for the sound source and the acoustic lens to be directly adjacent. Only a coupling for sound transmission is required. For example, a housing component can be positioned between the acoustic lens and the sound source. The sound source can be encapsulated, for example, by a loudspeaker enclosure. Such an enclosure is designed to allow sound to be transmitted to the acoustic lens, for example, through at least one opening in the housing. An enclosure or housing is particularly advantageous for low frequencies (bass).

[0046] In one embodiment, the sound source and the acoustic lens are arranged such that sound emanating from the acoustic lens is radiated downwards, particularly obliquely downwards. Specifically, the sound source is already positioned to emit sound obliquely downwards. It has been shown that this achieves a particularly low directivity of the resulting sound. In particular, the household appliance is designed and intended to be placed on a surface such as a table or countertop. In this case, the downward-directed sound allows for particularly effective sound transmission to the user.

[0047] In a further embodiment, the acoustic lens is located at a distance of at most 5 cm, preferably at most 4 cm, particularly preferably at most 3 cm and / or at least 1 cm, preferably at least 1.5 cm or at least 2 cm, from the surface on which the household appliance is placed. The underside of a household appliance incorporating the acoustic lens may be inclined. Accordingly, the distance may vary depending on its position. The values ​​mentioned refer in particular to an average distance.

[0048] Typically, the appliance includes mounting elements such as feet. The mounting surface is a flat plane defined by these mounting elements. If the appliance is placed on a flat surface such as a table or countertop, this flat surface constitutes the mounting surface. The distance is the shortest measured distance between the mounting surface and the acoustic lens. In an alternative configuration, the distance between the acoustic lens and the mounting surface of the appliance is a maximum of 5 cm.

[0049] In this way, when placed on a flat surface, in addition to the different sound components described above, a further sound component is generated, which is based on the reflection of the emitted sound waves at the surface. This allows an even larger area to be covered with sound almost uniformly. In one embodiment, the direct sound is reflected.

[0050] In one embodiment, the acoustic lens is inclined at an angle of at least 5°, preferably at least 10°, and in one example at least 15°, and / or at most 45°, preferably at most 35°, and particularly preferably at most 30°, relative to the surface on which the household appliance is placed. The angle is measured between the downward-facing surface of the acoustic lens and the surface on which the appliance is placed. In this way, the sound can be directed particularly effectively to the possible positions of the user via reflections from the surface.

[0051] In a further embodiment, the acoustic lens is arranged in a recording area of ​​the household appliance. This recording area has, in particular, a substantially smooth back wall.

[0052] The rear wall is the wall that bounds the recording area from behind. In particular, the rear wall is at least substantially, and preferably completely, closed. This is not contradicted by the fact that the rear wall may have an opening for sound to enter the acoustic lens.

[0053] This design allows the back wall to act as a reflective surface for sound waves contained within the acoustic lens. Sound can only be emitted outwards through the acoustic lens.

[0054] In one embodiment, the acoustic lens is mounted in a receiving area of ​​the household appliance, in particular a housing of the household appliance. The receiving area has, in particular, the same contour as the acoustic lens, so that the acoustic lens can be inserted into the receiving area and then does not protrude, or only minimally protrudes, beyond the surrounding areas of the housing. In one embodiment, the acoustic lens is positively locked in place. In another embodiment, the acoustic lens is detachably mounted.

[0055] In one embodiment, a grille is present in the household appliance, e.g., in its housing, which mechanically protects the sound source. In another embodiment, the acoustic lens is dimensioned such that the user can grasp, handle, and / or carry the household appliance over the acoustic lens without damaging the acoustic lens or the sound source. The acoustic lens thus possesses a certain rigidity that provides it with stability. In this way, the acoustic lens offers the sound source additional mechanical protection.

[0056] In one embodiment, the outer contour of the sound source and the contour of the entrance area of ​​the acoustic lens are essentially corresponding in shape. For example, an approximately circular shape can be chosen, which can particularly correspond to the shape of the loudspeaker used. To ensure mechanical protection for the loudspeaker, struts and / or a grille can be present in the area of ​​the aforementioned shape, for example on a housing.

[0057] In one embodiment, the sound paths run obliquely towards a front or front edge of the appliance. In other words, the sound paths run diagonally forward relative to the appliance. If there is a surface that essentially limits the appliance at the front, this can be the front. Otherwise, a front edge is typically present. The front edge is typically rounded. A front edge is the edge or side that faces the user during normal use.

[0058] The forward-facing sound paths ensure that the user in front of the appliance is effectively exposed to sound, regardless of their exact position.

[0059] Another aspect of the invention is the use of an acoustic lens, in particular an acoustic lens according to the invention, to influence the radiation behavior of a sound source, especially in a household appliance such as a kitchen machine.

[0060] Exemplary embodiments of the invention are explained in more detail below, also with reference to figures. Features of the exemplary embodiments can be combined individually or in multiples with the claimed subject matter, unless otherwise specified. The claimed scope of protection is not limited to the exemplary embodiments.

[0061] They show: Figure 1 : an acoustic lens viewed from an oblique angle above; Figure 2 : an acoustic lens viewed from a low angle; Figure 3 : a household appliance with an acoustic lens; Figure 4 : a household appliance with a recording area for an acoustic lens; Figure 5: a household appliance with a recording area and an acoustic lens; Figure 6 : a cross-sectional view of a household appliance with an acoustic lens; Figure 7 : a perspective sectional view of a household appliance; Figure 8 : another perspective sectional view of a household appliance; Figure 9 : a sectional drawing of a household appliance with an acoustic lens from the front; Figure 10 : a sectional drawing of a household appliance without an acoustic lens from the front; Figure 11 : a sectional drawing of a household appliance with an acoustic lens from the front; Figure 12 : a cross-sectional drawing of a household appliance with a partially closed acoustic lens from the front; Figure 13 : a sectional drawing of a household appliance with an acoustic lens from the front; Figure 14 : another acoustic lens; Figure 15 : another acoustic lens; as well as Figure 16 : a household appliance with a speaker module.

[0062] Figure 1 Figure 1 shows an acoustic lens 1 from a slightly oblique angle above. The entrance area 4 is located approximately in the center at the top. A sound source, such as a loudspeaker, can be positioned above the entrance area 4 to direct sound waves into the acoustic lens. Below the entrance area 4 is a direct path, which, for example, Figure 7 and explained in the accompanying description. Sound waves from the sound source can be emitted directly through acoustic lens 1 via the direct path.

[0063] The entrance area 4 comprises a distribution area 15, from which a multitude of sound paths originate, leading into Figure 6The sound paths are defined by the guide elements 10 of the sound delay area 5. The guide elements 10 are designed as curved struts of different lengths. The outermost sound paths are the longest, while the innermost sound paths are shorter. In this way, a particularly strong defocusing of the sound can be achieved, as shown in Figure 11 is shown.

[0064] The struts have a flat underside from which wall-like extensions extend vertically upwards. Initially, the sound travels outwards along the sound paths within the acoustic lens 1, through the cavities located between the struts. To guide this sound along the respective sound path, the wall-like extensions of the struts serve as guiding surfaces 12 extending in the direction of the sound. Subsequently, the upper surfaces of the flat struts act as deflection elements 13 to deflect the sound and retain it inside through reflection.

[0065] Along the sound paths, the entire structure of the struts, for example in cross-section approximately L-shaped, also serves as a conductive surface 12. At the end of the sound paths, the sound encounters an outer frame of the acoustic lens 1, which serves as a deflecting element 13. The sound is reflected at this and, if necessary after further reflection at a rear wall, cf. Figure 4, directed outwards or downwards perpendicular to the main extension plane of the acoustic lens 1.

[0066] The acoustic lens 1 is designed as an irregularly shaped grating 20, with the webs forming the guiding elements 10 creating open spaces between them. These spaces serve as exit openings for sound.

[0067] The acoustic lens 1 further comprises several hooks 27 and a fastening 25, which is designed, for example, as a flexible or flexible hook. This allows for a positive-locking and, in particular, non-destructively detachable connection with a household appliance. For example, a click connection is possible.

[0068] Contrary to the above, Figures 1 to 15The acoustic lens shown can have rounded edges. For example, the narrow edges can be semicircular. This allows for the creation of sound paths of varying lengths in a particularly suitable way.

[0069] The guiding elements 10 and deflecting elements 13 correspond to obstacles that are, in particular, smaller than the sound wave paths under consideration. The guiding elements 10 and guiding surfaces 12 are preferably arranged, especially with regard to their spacing, such that they are optimized for a specific frequency or frequency range. This frequency range can, for example, be 5 to 20 kHz. The wavelength, which can be calculated as the quotient of the speed of sound and the frequency, is 3.4 cm at 10 kHz. Preferably, the distance between the guiding elements 10 and their deflecting elements 13 is approximately half the wavelength. Deviations of ±30%, preferably ±15%, are acceptable. This ensures particularly effective sound delay.

[0070] Figure 2Figure 20 shows the acoustic lens 1, designed as a grating 20, from below or from the sound exit side. It can be seen that the acoustic lens 1 also includes fracture edges 6 at which sound is reflected, thus creating indirect sound sources (cf. Figure 2). Figure 12 The fracture edges 6 are arranged on the outer edges of the guide elements 10 or webs and, in the example shown here, have an angle of approximately 90°. In particular, the edges of the guide elements 10 facing away from at least part of the entrance area, i.e., those facing away from the direction of the sound, serve as fracture edges 6. These can radiate sound as indirect sound sources over a wide angular range.

[0071] The guiding elements 10, for example the guiding surfaces 12 and deflection elements 13, as well as the fracture edge 6, can therefore be realized by the same physical features, for example by different areas of the same physical features such as e.g. of webs.

[0072] A protective layer, particularly an acoustically transparent mesh or fabric, may be present, spanning, for example, the entire underside and / or the entire sound-emitting side. This may be injected into the acoustic lens 1 or bonded to it, for example, by adhesive. On the visible underside of the acoustic lens 1, the outer surfaces of the guiding elements 10 or webs form a common outer surface 17, which may be flat. The mesh or fabric may be stretched over this surface. Alternatively, the surface may also be structured. This may be the case, for example, if the fracture edges are designed to protrude from the surface.

[0073] Figure 3Figure 2 shows a household appliance, namely a kitchen appliance, which includes an acoustic lens 1. The viewing direction leads through the household appliance 2 diagonally forward to the inner upper surface of the acoustic lens 1. A sound source 3 (see also Figure 7 ) is located adjacent to the acoustic lens 1 and is sound-conductingly coupled to the entrance area 4.

[0074] Figure 4 shows a household appliance 2, for example, the household appliance 2 from Figure 3 , without the acoustic lens 1 in a perspective view from a low angle. Typically, a receiving area 22 is provided in a lower housing part of the household appliance 2, into which the acoustic lens 1 can be received and attached. The receiving area 22 is designed as a recess into which the acoustic lens 1 can be inserted, in particular such that the surface 17 (cf. Figure 2) flush with the adjacent housing wall of the household appliance 2. This creates a flat surface.

[0075] A rear wall 23 of the receiving area 22 is smooth. This allows the rear wall to reflect sound waves, which can then only pass through the acoustic lens 1. Minor deviations from the smooth shape, such as those caused by the mounting holes shown or other design features, are permissible. Such deviations must affect less than 10% of the surface of the receiving area 22. A grid-like structure with openings is located centrally in the rear wall 23, behind which the sound source is positioned. The grid-like structure thus serves as additional protection for the sound source. In the assembled state, the entrance area of ​​the acoustic lens 1 is located adjacent to this structure.

[0076] Figure 5The household appliance displays 2 out Figure 4 with the attached acoustic lens 1. Also indicated is a front edge 24 of the household appliance. The acoustic lens 1 is thus located on the front underside of the household appliance 2 and is therefore facing the user. Arrows indicate the sound 26 emitted forward from the sound delay area in the direction of the user. Bent arrows indicate the sound emitted via the direct path 18, which in this embodiment is reflected off a surface (not shown) on which the household appliance 2 is placed and is emitted forward towards the user as reflected sound 19.

[0077] Figure 6 shows a sectional view of a household appliance 2 with an acoustic lens 1, in particular of the household appliance 2 made of Figure 5It is cut along a vertical central axis, so that the sound source 3 and the inlet area 4 with the distribution area 15 are visible. Arrows show the sound waves emitted via the sound delay area 5 and thus the respective sound paths 11, which are defined by the respective guiding elements 10 as described above. It can be seen that in the inlet area 4, which is free of guiding elements 10, the sound waves coming from the sound source 3 are distributed. It is also evident that the sound paths 11 ending on the outside are the longest and thus cause the greatest delay.

[0078] Figure 7 shows a similar sectional view of a household appliance 2, for example, the household appliance 2 from Figure 6, from a slightly oblique angle above. Here, the sound source 3, designed as a loudspeaker, with its associated loudspeaker housing 46 is clearly visible. The loudspeaker is therefore encapsulated in its own loudspeaker housing 46. The loudspeaker housing 46 has, for example, an opening on the side shown below, through which the sound reaches the acoustic lens 1.

[0079] Furthermore, a mounting surface 21 is shown, which corresponds, for example, to the surface of a worktop or table on which the household appliance 2 is placed. The distance d between the acoustic lens 1 and the mounting surface 21 of the household appliance 2 is between 1.5 cm and 3.5 cm. This allows the reflection of the high frequencies to be directed particularly effectively towards the user.

[0080] Figure 8 shows a similar representation of a household appliance 2 from a slightly elevated angle, for example, the household appliance from Figure 6 and / or from Figure 7. In analogy to Figure 6 Identify the sound paths marked with arrows.

[0081] The Figures 9 to 13 show sectional drawings of a household appliance 2, partly with acoustic lens 1, from the front. Figure 9 Figure 5 illustrates the effect of the sound delay zone, where the length of the arrows corresponds to the loudness or sound pressure. It depicts a snapshot at the beginning of a sound event. The arrows show that the largest proportion of the sound emanates from the center, which is due to the direct sound. The further away the sound emanates, the lower the loudness. Subsequently, due to the delay effect, a higher loudness is achieved even at these points.

[0082] Figure 10 This shows the effect of direct sound alone without an acoustic lens 1. Direct sound 14 is emitted exclusively from the center and is represented in the form of sound waves.

[0083] Figure 11Figure 1 shows a similar representation of the combination of direct sound 14 and sound 9 delayed via the sound delay region 5. Within the sound delay region 5, numerous indirect sound sources are present due to the different exit openings of the respective sound paths, enabling a wide sound propagation, as shown in the form of the resulting sound 16. The delay and the decreasing volume towards the outside lead to a defocusing of the sound. The delayed sound 9 can be emitted in a straight line.

[0084] Figure 12 The combination of direct sound 14 and indirect sound 8 emitted via the fracture edges 6 is shown. For this purpose, a closure 28 in the form of a plate is provided, which closes the sound paths of the sound delay area 5. The direct sound 14 is only allowed through in the center. Through the fracture edges 6 (cf. Figure 2A multitude of indirect sound sources 7 are provided, which reflect the sound emitted from the center and radiate the sound directed outwards. This also enables a wide sound propagation, as shown in the form of the resulting sound 16.

[0085] The inventive combination of these two effects is now being used in Figure 13 shown. Here, direct sound 14, delayed sound 9 and indirect sound 8 superimpose to form a particularly wide-angle radiated resultant sound 16. This is recognizable by the particularly broad, diverging sound front of the resultant sound 16. In addition, it is possible that the delayed sound 9 is also reflected via the fracture edges 6 and emits an additional, so to speak doubly delayed, indirect sound.

[0086] The Figures 14 and 15 show differing designs of acoustic lenses 1. In Figure 14The guiding elements are 10 wider and in Figure 15 significantly wider. The curvatures of the guide elements 10 are adapted to obtain a particularly uniform resulting sound. In Figure 15 Furthermore, the wall-like guide surfaces are longer and curved to direct the sound more precisely in the desired direction. In addition to these technically determined features, aesthetic considerations can also play a role, particularly regarding the shape and arrangement of the guide elements.

[0087] Figure 16Figure 1 shows a section of a household appliance 2, specifically a kitchen appliance. The household appliance comprises a housing 40, which is preferably made of plastic. A loudspeaker module 44, which in turn comprises a loudspeaker housing 46, is located in the housing 40. The loudspeaker housing 46 is typically attached to the housing 40 of the kitchen appliance 2. At least one loudspeaker is arranged in the loudspeaker housing 46 as a sound source. Preferably, the loudspeaker module 44 is designed such that sound from the loudspeaker is emitted downwards or at an angle. For example, the loudspeaker module 44 has one or more openings on its underside to direct the sound to the acoustic lens.

[0088] Below the loudspeaker module 44 is the acoustic lens 1. The loudspeaker module is acoustically coupled to the entrance area of ​​the acoustic lens, for example as shown in Figure 3As shown. A recording area for the acoustic lens 1 may be present on the underside of the household appliance 2, as shown in Figure 4 shown. In particular, the acoustic lens 1 is removable from the housing 40 of the household appliance 2.

[0089] The sound thus travels from the loudspeaker housing 46 and the housing 40 of the household appliance 2 to the acoustic lens. Preferably, the loudspeaker housing 46 and also the housing 40 provide mechanical protection for the loudspeaker. Reference symbol list

[0090] Acoustic lens 1 household appliance 2 sound source 3 Entrance area 4 Sound delay range 5 fracture edge 6 Indirect sound source 7 Indirect sound 8 Delayed sound 9 Conductive element 10 sound path 11 Guide surface 12 Deflection element 13 Direct sound 14 Distribution area 15 Resultant sound 16 surface 17 Direct path 18 Reflected sound 19 Grid 20 Installation level 21 Recording area 22 back panel 23 leading edge 24 fastening 25 Emitted sound 26 Hook 27 Closure 28 Housing 40 speaker module 44 speaker enclosure 46 Distance d

Claims

1. Acoustic lens (1) for influencing the radiation behavior of a sound source (3), comprising - an inlet area (4) for the entry of sound waves from a sound source (3), - a sound delay area (5) for delaying sound waves, and - at least a break edge (6) for reflecting sound waves to create an indirect sound source (7).

2. Acoustic lens (1) according to the preceding claim, characterized by the fact that the sound delay region (5) is arranged such that sound waves entering through the entrance region (4) are generated with different delays.

3. Acoustic lens (1) according to any one of the preceding claims, characterized by the fact that the sound delay area (5) includes several guiding elements (10) to form sound paths (11) of different lengths.

4. Acoustic lens (1) according to the preceding claim, characterized by the fact thatthe guiding elements (10) include guiding surfaces (12) extending in the direction of sound and deflection elements (13) adjoining them.

5. Acoustic lens (1) according to one of the two preceding claims, characterized by the fact that the acoustic lens (1) in the entrance area (4) comprises a distribution area (15) at which the sound paths (11) start, wherein the distribution area (15) is in particular free of guiding elements (10).

6. Acoustic lens (1) according to any one of the preceding claims, characterized by the fact that the fracture edge (6) is located on a surface (17) of the acoustic lens.

7. Acoustic lens (1) according to any one of the preceding claims, characterized by the fact that the acoustic lens (1) comprises several fracture edges (6).

8. Acoustic lens (1) according to any one of the preceding claims, characterized by the fact thatthe acoustic lens (1) has a direct path (18) through which a portion of the sound waves entering through the entrance area (4) are emitted essentially unchanged.

9. Acoustic lens (1) according to any one of the preceding claims, characterized by the fact that the acoustic lens (1) is designed as a grating (20).

10. Household appliance (2) with an acoustic lens (1) according to one of the preceding claims and a sound source (3) coupled to the entrance area (4) of the acoustic lens (1), wherein the sound source (3) is in particular a loudspeaker.

11. Household appliance (2) according to the preceding claim, characterized by the fact that the household appliance (2) is a food processor.

12. Household appliance (2) according to one of the two preceding claims, characterized by the fact thatthe sound source (3) and the acoustic lens (1) are arranged such that sound emanating from the acoustic lens is radiated downwards, in particular obliquely downwards.

13. Household appliance (2) according to one of the three preceding claims, characterized by the fact that the acoustic lens (1) has a distance (d) of at most 4 cm, preferably at most 3 cm and / or at least 1 cm, preferably at least 2 cm, to a mounting surface (21) of the household appliance (2).

14. Household appliance (2) according to one of the four preceding claims, characterized by the fact that the acoustic lens (1) is arranged in a recording area (22) of the household appliance (2), wherein the recording area (22) has a substantially smooth rear wall (23).

15. Household appliance (2) according to one of the five preceding claims, insofar as it relates back to claim 3, characterized by the fact that the sound paths (11) run obliquely towards a front or front edge (24) of the household appliance (2).

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