Laminated glass speaker system including asymmetric piezoelectric exciter

Abstract

A laminated glass speaker system includes at least one pair of asymmetric piezoelectric exciters within a laminate material effective to bond glass panels together. The laminated glass speaker system may be used anywhere around the vehicle where sound is desired to be generated, such as passenger windows, fixed or sliding roof systems, front windshields, rear windshields, side windows, rear quarter glass, and the like. The piezoelectric exciter is generally off-axis with respect to a centerline extending longitudinally between the glass panels and acts as a diaphragm to produce sound upon vibration.

Description

Technical Field

[0001] The present disclosure relates to laminated vehicle glazing structures, and more particularly, to laminated vehicle glazing structures including asymmetric piezoelectric actuators for regional sound generation, wherein the piezoelectric actuators are at least partially and / or completely embedded in a polymer laminate material disposed between glass panels. Background Art

[0002] Laminated glass is a type of safety glass commonly used in vehicles that consists of two or more sheets of glass bonded together by layers of polyvinyl butyral (PVB) or other similar materials. The glass and interlayer are heated and pressed together to create a strong and durable bond. Laminated glass offers several advantages over traditional single-layer glass, including increased strength, durability, and safety. When laminated glass breaks, the interlayer holds the glass fragments together, reducing the risk of injury from sharp edges and preventing the glass from shattering and falling apart.

[0003] Known glass panels can be made of heat ray absorbing glass, conventional transparent glass, green glass or UV green glass. In some embodiments, adjustments can be made so that the outer glass panel ensures the desired solar energy and / or tint absorption rate and the inner glass panel provides visible light transmittance. Other materials can also be used as laminated transparent panels, including but not limited to polycarbonate resins.

[0004] Current speaker technology used in vehicles typically employs electromagnetic speakers including moving coil and cone technology, which are placed in doors, dashboards, roofs, and other places throughout the vehicle to produce sound. The speaker acts as a transducer to convert amplified electrical waves from infotainment systems, phones, etc. into sound pressure waves that propagate through the air for passengers to hear. The amplifier feeds the signal to two terminals on the back of the speaker. These terminals pass the current into a cylindrical wire coil that is suspended in a circular gap between the poles of a permanent magnet. According to Faraday's law, the coil moves back and forth within the magnetic field as the current through the coil alternates in direction with the applied signal. The center of the speaker cone is attached to one end, which is driven back and forth by the moving coil. The cone is held at its edges by an airtight suspension or surround. As the cone moves, it pushes and pulls the surrounding air; by doing so, it creates pressure waves in the air in the form of sound.

[0005] Coil and cone speakers add considerable weight to the vehicle, require separate mounting and connections, take up valuable interior trim space, allow for significant road noise intrusion, and are subject to considerable impact and environmental damage. In addition, today's high-end automotive audio systems require multiple speakers discretely positioned in highly defined locations within the vehicle interior. This eliminates other features, such as the size of the roof opening for fixing or moving the roof glass panel. In addition, due to the limited trim space available for speaker placement, the speakers may be poorly positioned for listening. Their on-axis radiation is often directed low in the vehicle toward the legs and upper abdomen of the passenger rather than at the passenger's ears. The direct sound from the speaker to the listener is often far off axis, and the frequency response is highly variable, often with insufficient high frequencies. In the high noise environment of the vehicle, this often results in a loss of mid- and high-frequency audio information. "Imaging," the perception of where the sound is coming from, is also adversely affected because the speakers are low in the vehicle; for the front passengers, the audio image is pulled down into the door, while the rear passengers have an image to the side or rear, rather than what should be presented in front of them.

[0006] Therefore, it is desirable to better position speakers within a vehicle while minimizing trim space requirements, weight, road intrusion noise, drawbacks, etc. Summary of the invention

[0007] In an exemplary embodiment of the present disclosure, a laminated glass structure for a vehicle includes: a first glass panel, the first glass panel including an inner surface and an outer surface facing the vehicle's surrounding environment; and a second glass panel, the second glass panel including an inner surface and an outer surface facing the vehicle's interior. A laminate material is located between the inner surfaces of the first glass panel and the second glass panel, effectively bonding the first panel to the second panel. At least one pair of spaced-apart piezoelectric actuators is disposed between the first glass panel and the second glass panel. The thickness of each piezoelectric actuator is less than the thickness of the laminate material. One of the piezoelectric actuators is at a different vertical position relative to the other piezoelectric actuator, and the two piezoelectric actuators are offset relative to a centerline extending longitudinally between the first glass panel and the second glass panel.

[0008] In other aspects, one piezoelectric actuator is disposed on an inner surface of a first glass panel and another piezoelectric actuator is disposed on an inner surface of a second glass panel.Each piezoelectric actuator of the at least one pair of piezoelectric actuators may be fully encapsulated within the laminate.

[0009] In one or more embodiments, the laminated glass structure further comprises a plastic layer, the plastic layer comprising a first planar surface and a second planar surface and a sidewall extending between the first planar surface and the second planar surface, the sidewall defining a thickness of the plastic layer, wherein one piezoelectric actuator is disposed on the first planar surface of the plastic layer, and another piezoelectric actuator is disposed on the second planar surface of the plastic layer. The plastic layer may comprise polyethylene terephthalate.

[0010] The laminate material may include polyvinyl butyral resin or ethylene vinyl acetate. The laminate material may have a thickness of about 0.3 mm to about 2 mm, and each piezoelectric actuator may have a thickness of less than 0.6 mm. In one or more aspects, the piezoelectric actuator is powered via the infotainment system to generate sound. The piezoelectric actuator may include lead zirconium titanate, calcium titanate, barium titanate, lead titanate, or strontium titanate.

[0011] In another embodiment of the present disclosure, a laminated glass structure for a vehicle includes: a first glass panel including an inner surface and an outer surface facing the vehicle's surrounding environment; and a second glass panel including an inner surface and an outer surface facing the vehicle's interior. A laminate material is located between the inner surfaces of the first glass panel and the second glass panel, effectively bonding the first panel to the second panel. At least one pair of spaced-apart piezoelectric actuators are disposed between the first glass panel and the second glass panel and are located at the same vertical position. The at least one pair of piezoelectric actuators are offset relative to a centerline extending longitudinally between the first glass panel and the second glass panel. Each of the piezoelectric actuators has a thickness less than the thickness of the laminate material, and a selected one of the at least one pair of piezoelectric actuators is configured to generate a sound having an opposite phase relative to the other piezoelectric actuator.

[0012] In one or more aspects, the selected one of the at least one pair of piezoelectric actuators configured to produce sound with opposite phase may include positive and negative electrical wiring with reversed polarity relative to the other piezoelectric actuator. In other aspects, the selected one of the at least one pair of piezoelectric actuators configured to produce sound with opposite phase may include positive wiring and negative electrical wiring with reversed orientation and same polarity relative to the other piezoelectric actuator. During operation, the at least one pair of piezoelectric actuators cancels sound produced at a plane of symmetry between the pair of piezoelectric actuators.

[0013] In one or more aspects, there are two equally spaced pairs of piezoelectric actuators, wherein each adjacent pair of piezoelectric actuators includes a piezoelectric actuator that is configured to produce sound having an opposite phase relative to the other piezoelectric actuator, and each pair of piezoelectric actuators that are diagonal to each other have the same phase.

[0014] In the laminated glass structure, the laminate material has a thickness of about 0.3 mm to about 2 mm, and wherein the piezoelectric actuator has a thickness of less than 0.6 mm. The piezoelectric actuator can be powered via an infotainment system to generate sound. The laminate material can include polyvinyl butyral resin or ethylene vinyl acetate.

[0015] In one or more embodiments, the laminated glass structure further comprises a plastic layer disposed within the laminate material, the plastic layer comprising a first planar surface and a second planar surface and a sidewall extending between the first planar surface and the second planar surface, the sidewall defining a thickness of the plastic layer, wherein the plastic layer comprises polyethylene terephthalate.

[0016] In yet another embodiment of the present disclosure, a laminated glass structure for a vehicle includes: an outer glass panel having a thickness of about 1.6 mm to about 3.5 mm, the outer glass panel including an inner surface and an outer surface exposed to the environment surrounding the vehicle; and an inner glass panel having a thickness of about 0.7 mm to about 3.5 mm, the inner glass panel including an inner surface and an outer surface exposed to the interior of the vehicle. A laminate having a thickness of about 0.3 mm to about 2 mm is located between the outer glass panel and the inner glass panel and contacts the inner surface of the outer glass panel and the inner surface of the inner glass panel. The laminate includes polyvinyl butyral resin or ethylene vinyl acetate. At least one pair of asymmetric piezoelectric actuators is located between the outer glass panel and the inner glass panel and is offset relative to a centerline extending between the inner surface of the outer glass panel and the inner surface of the inner glass panel. The at least one pair of asymmetric piezoelectric actuators is annular and has a thickness less than the thickness of the laminate. Each piezoelectric actuator in the at least one pair of piezoelectric actuators is in a different vertical position or the same vertical position. One of the piezoelectric actuators is configured to generate sound with opposite phase when in the same vertical position. The sound cancels at a plane of symmetry between the piezoelectric actuators in the at least one pair of piezoelectric actuators. The laminated glass structure forms a fixed or sliding roof system, one or more passenger movable windows, a front windshield, and / or a rear windshield.

[0017] The above features and advantages and other features and advantages of the present disclosure are apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features, advantages and details appear, by way of example only, from the following detailed description, which refers to the accompanying drawings, in which:

[0019] Figure 1 shows a perspective view of an exemplary vehicle including a plurality of laminated glass panels;

[0020] Figure 2 is a cross-sectional view of a laminated glass structure including a pair of spaced apart asymmetric piezoelectric actuators positioned on each of the interior surfaces of the glass panel and partially embedded within the laminate material according to one or more embodiments of the present disclosure;

[0021] Figure 3 is a cross-sectional view of a laminated glass structure according to one or more embodiments of the present disclosure, the laminated glass structure including a pair of spaced apart asymmetric piezoelectric actuators positioned on a common interior surface of a selected one of the glass panels, wherein the piezoelectric actuators are configured to generate sounds having opposite phases;

[0022] Figure 4 is a cross-sectional view of a laminated glass structure according to one or more embodiments of the present disclosure, the laminated glass structure including a pair of spaced apart asymmetric piezoelectric actuators positioned within the laminate at opposite locations relative to a centerline extending longitudinally between glass panels;

[0023] Figure 5 is a cross-sectional view of a laminated glass structure including a rigid plastic layer at a centerline between opposing glass panels and an asymmetric piezoelectric actuator embedded within the laminate off-axis relative to the centerline in accordance with one or more embodiments of the present disclosure;

[0024] Figure 6 a contour plot depicting total sound pressure level in decibels for a laminated glass structure including a pair of spaced-apart asymmetric piezoelectric actuators configured to produce sound in opposite phases according to one or more embodiments of the present disclosure;

[0025] Figure 7 Describes a method according to one or more embodiments of the present disclosure. Figure 6 The line AA intercepts Figure 5 a contour plot of a cross-sectional view of the total sound pressure (in Pascals) of the laminated glass structure; and

[0026] Figure 8 Contour graph depicting total sound pressure level in decibels for a laminated glass structure including four spaced-apart asymmetric piezoelectric actuators configured to generate sound according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0027] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses.

[0028] According to an exemplary embodiment, a motor vehicle includes a laminated glass structure including at least one pair of ceramic piezoelectric actuators that are asymmetrically incorporated within the laminated glass panel to recreate the area effects of current electromagnetic systems, such as those located in a headliner mounting system. The laminated glass panel for a motor vehicle is typically a laminated structure that includes an outer glass panel including sides 1, 2 and an inner glass panel including sides 3, 4 that are laminated together using a polymer laminating material. The outer-facing surface of the outer glass side panel is referred to as side 1, and the corresponding inner surface is referred to as side 2. The inner surface of the inner glass side panel is referred to as side 3, and the corresponding inner-facing glass surface is referred to as side 4.

[0029] At least one pair of piezoelectric actuators can be asymmetrically positioned within the laminate, with, for example, one piezoelectric actuator bonded directly to side 2 of the automotive laminated glass and the other piezoelectric actuator bonded to side 3 of the automotive laminated glass. The pair of piezoelectric actuators are spaced apart from one another and can be placed in proximity to seated passengers. This asymmetrical arrangement produces multiple zones of sound generation with dead spots between zones. Laminated glass structures according to the present disclosure can be used for front windshields, fixed roof systems, sliding glass roof systems, side sliding glass, rear quarter glass, and rear glass, and are typically formed from glass panels having a shape intended for their use. For example, fixed roof applications typically utilize rectangular glass panels laminated together.

[0030] The piezoelectric actuator is annular and is an actuator that converts electrical energy into mechanical energy using a piezoelectric material. The actuator can be an annular piezoelectric material, typically made of lead zirconium titanate (PZT), which is sandwiched between two electrodes. When a voltage is applied to the electrodes, the piezoelectric material expands or contracts, causing the ring to deform and produce mechanical movement. In the present disclosure, the thickness of the piezoelectric actuator is less than the thickness of the (multiple) laminated materials in the middle of the glass panel. In one or more embodiments of the present disclosure, the piezoelectric actuator is selected to have a thickness of less than 0.6 millimeters (mm), wherein at least one pair of piezoelectric actuators are asymmetrically arranged within the laminated glass, as will be described in more detail, to provide regional sound generation.

[0031] Piezoelectric actuators suitable for use in the present disclosure include, but are not limited to, hard piezoelectric ceramic materials for exciting and causing vibrations in the glass panel. Exemplary hard piezoelectric ceramic materials include piezoelectric shaped rings, such as those of circular, elliptical, polygonal, or any other geometric shape that may be used, and are typically used as diaphragms in laminated glass structures in a manner similar to a coil-cone speaker.

[0032] Hard piezoelectric actuators typically have a higher mechanical quality factor than soft piezoelectric actuators, which are usually configured as membranes. Hard piezoelectric ceramics are suitable for dynamic / resonant applications, and the higher mechanical quality factor provides more efficient energy conversion (from electricity to work). Hard materials can withstand high levels of electrical excitation and mechanical stress, generate less heat during the process, and are not easily polarized or depolarized except at elevated temperatures. Hard piezoelectric materials exhibit reduced strain due to the lower charge coefficient (d) compared to soft piezoelectric materials.

[0033] In one or more embodiments, a hard piezoelectric ring made of PZT-4 material (lead zirconium titanate) can be used, for example, which can be made relatively thin and used as a diaphragm. Other types include but are not limited to calcium titanate, barium titanate, lead titanate, strontium titanate, etc.

[0034] The piezoelectric actuator may be supplied with regulated power via the vehicle's infotainment system. For example, the infotainment amplifier system may be electrically coupled to the piezoelectric actuator using a patterned conductive coating directly on the glass surface within the laminate structure and / or by using negative and positive leads electrically coupled to the piezoelectric actuator, which may or may not be insulated if sufficiently spaced from one another. In the case of a patterned conductive surface within the laminate structure, the conductive surface would be provided on the side 2 or 3 of the glass panel, or on a selected surface of the plastic layer, if present within the laminate material.

[0035] Although reference is made to two glass panels, it should be apparent that more than two glass panels may be used, although the increase in weight would make this less practical for automotive applications. Laminated glass assemblies including asymmetric piezoelectric actuators may be used anywhere in a vehicle, where the laminated glass assembly is used, including, for example, fixed glass roof systems, front windshields, side sliding glass, rear quarter glass, rear glass, etc. Unlike coil and cone based speakers, piezoelectric actuators advantageously occupy minimal space, have significantly lower weight, can be used to occupy space within a vehicle that was not previously used for speaker placement (i.e., in laminated glass structures), and, in contrast to coil and cone speakers that are typically placed within a trim panel (e.g., a door panel) below a vehicle window, piezoelectric actuators may be located above and / or beside a passenger(s).

[0036] As used herein, when referring to a laminated glass structure comprising two glass panels, the terms "ambient glass side" and "exterior glass side" are interchangeable and generally refer to the glass panel that includes a surface exposed to the environment. Conversely, the terms "cabin glass side" and "interior glass side" are interchangeable and generally refer to the glass panel that includes a surface exposed to the interior of the vehicle. The term "asymmetric" refers to the vertical position of a pair of piezoelectric actuators within a polymer laminate, wherein each piezoelectric actuator is at a different plane between the glass panels in the laminated glass structure, or the pair of piezoelectric actuators are at the same vertical position (same plane), wherein one of the piezoelectric actuators is configured to generate an acoustic wave in opposite phase relative to the other piezoelectric actuator in the pair.

[0037] Conventional techniques associated with the laminated glass manufacturing process may or may not be described in detail herein. In addition, the various tasks and process steps described herein may be incorporated into a more comprehensive program or process having additional steps or functions not described in detail herein. In particular, the various steps in the windshield manufacturing process are well known, and therefore, for the sake of brevity, many conventional steps will only be briefly mentioned herein or will be omitted entirely without providing well-known process details.

[0038] For ease of description, spatially relative terms, such as "below," "beneath," "lower," "above," "upper," etc., may be used herein to describe the relationship of one element or feature to another or more elements or features as shown in the figures. It should be understood that the spatially relative terms are intended to cover different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the drawings is turned over, elements described as being "below" or "beneath" other elements or features will be oriented as being "above" the other elements or features. Thus, the term "below" can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0039] The following definitions and abbreviations are used to interpret the claims and specification. As used herein, the terms "comprise, comprising," "include," "has," "having," "contains," or "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, mixture, process, method, article, or apparatus comprising a list of elements is not necessarily limited to only those elements, but may include other elements not expressly listed or inherent to such composition, mixture, process, method, article, or apparatus.

[0040] The terms "one" and "a kind of" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced items. Unless the context clearly indicates otherwise, the term "or" means "and / or". References to "aspects" throughout the specification mean that specific elements (e.g., features, structures, steps, or characteristics) described in conjunction with the aspect are included in at least one aspect described herein, and may or may not exist in other aspects. In addition, it should be understood that the described elements may be combined in any suitable manner in various aspects. In addition, the terms "upper", "lower", "top", "bottom", "left", and "right" and their derivatives shall relate to the described structures as they are oriented in the accompanying drawings. The same numbers in the various figures may refer to the same structural components or portions thereof.

[0041] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0042] Unless otherwise indicated herein, all test standards are the most current standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0043] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0044] There are generally a number of ways to achieve asymmetry with paired piezoelectric actuators. The piezoelectric actuators can be attached to opposing interior surfaces of the glass panel (e.g., on sides 2 and 3); the piezoelectric actuators can be in the same plane within the laminate, albeit offset relative to the centerline axis, wherein one of the piezoelectric actuators is flipped in orientation so that the sound produced by each piezoelectric actuator has an opposite phase relative to the other piezoelectric actuator; and the piezoelectric actuators can be in the same plane within the laminate, albeit offset relative to the centerline axis, wherein the polarity of the positive and negative wires used to power the piezoelectric actuators has a different polarity for one of the piezoelectric actuators relative to the other piezoelectric actuator.

[0045] like Figure 1 , a perspective view of an exemplary vehicle 1 is depicted, and includes multiple glass panels for a front windshield 2, a fixed roof system 3, a movable glass roof system (not shown), side movable glass 4, rear side glass (not shown), and rear glass 5. The arrangement, shape, and / or location typically vary between different vehicles.

[0046] like Figure 2As shown in , there is a cross-sectional view of a laminated glass structure 10 for a motor vehicle in accordance with one or more embodiments of the present disclosure, wherein piezoelectric actuators may be attached to opposing inner surfaces of glass panels (e.g., on sides 2 and 3). The laminated glass structure 10 includes at least one pair of asymmetrically disposed piezoelectric actuators 12, 14 within one or more polymer laminates 16, one of the polymer laminates 16 being shown, the polymer laminate being used to laminate a first glass panel 18 to a second glass panel 20. The first glass panel 18 includes an inner surface 24 and an outer surface 22 (side 1)(side 2) facing the external environment surrounding the vehicle. The second glass panel 20 includes an outer surface 28 and an inner surface 26 (side 3)(side 4) facing the interior of the vehicle. The piezoelectric actuators 12, 14 are asymmetrically positioned within the polymer laminate 16 and within the thickness of the polymer laminate 16 about a centerline (C) extending longitudinally between the first glass panel 18 and the second glass panel 20, respectively (see, e.g., Figure 4 ) (i.e., the piezoelectric actuator is offset relative to the centerline). Piezoelectric actuator 12 is located on an inner surface 24 (i.e., Side 2) of first glass panel 18, and piezoelectric actuator 14 is located on an inner surface 26 (i.e., Side 3) of second glass panel 20.

[0047] The piezoelectric actuators 12, 14 can be secured to the surface of the polymer laminate sheet prior to assembly, or to the corresponding glass surface during the assembly and lamination process, without the need for special adhesives or formulations, bezels in the case of package handles located on the roof, or other labor intensive measures. By providing the piezoelectric actuators in the polymer laminate stackup, as opposed to mounting cone speakers, there are significant manufacturing benefits.

[0048] Although there is no particular limitation on the thickness of the laminated glass structure, for roof applications, the total thickness of the outer glass panel 18 is typically set within a range of about 1.6 to about 3.5 millimeters (mm), and the inner glass panel 20 is typically set within a range of about 0.7 to about 3.5 mm. The polymer laminate 16 and any additional sheets that may be used for various applications (such as solar reflectivity) may have a thickness in the range of 0.3 mm to about 2 mm, for example, but greater or lesser thicknesses may be used. For example, the laminate itself may have a thickness of about 0.80 mm.

[0049] The process of laminating a laminated glass structure generally involves applying heat and pressure to bond two or more layers of glass together with a sheet of a polymeric laminate (e.g., polyvinyl butyral, ethylene vinyl acetate, or the like) interposed therebetween. The polymeric laminate is generally melted or softened by heat, causing it to bond the layers of glass together and produce a strong, durable laminate.

[0050] The temperature range used for laminated glass is typically between 120°C and 150°C (248°F and 302°F), but some processes may use higher or lower temperatures, depending on the materials and equipment used.

[0051] The pressure range for laminating glass can vary widely depending on the specific lamination process, but is typically between 10 and 15 psi (0.7 to 1 bar). Some processes may use higher pressures to achieve a stronger bond, while other processes may use lower pressures to reduce the risk of damaging the glass. In some applications, a masking layer (also called decoration) may be formed of ceramic, ceramic metal, etc., and may be provided around the perimeter of one or both of the glass panels prior to lamination. These are often referred to as ceramic inks and are fused to the glass during the bending process.

[0052] Now go to Figure 3 , there is a cross-sectional view of a laminated glass structure 30 according to one or more embodiments of the present disclosure, wherein a pair of spaced apart piezoelectric actuators 32, 34 are disposed on the same inner surface (e.g., side 2 or side 3). The laminated glass structure 30 includes a first glass panel 38, a second glass panel 40, and one or more laminate materials 36 therebetween. The first glass panel 38 includes an outer surface 42 (side 1) facing the external environment surrounding the vehicle and an inner surface 44 (side 2). The second glass panel 40 includes an inner surface 46 (side 3) facing the interior of the vehicle and an outer surface 48 (side 4). As shown, a pair of piezoelectric actuators 32, 34 are both located on the inner surface 46 (side 3) of the second glass panel 40, at the same vertical position between the first glass panel 38 and the second glass panel 40, respectively. The thickness of the piezoelectric actuators 32, 34 is less than the thickness of the laminate material 36. To provide asymmetry, one of the piezoelectric actuators 32 or 34 is flipped in orientation relative to the other, so that the piezoelectric actuators produce sounds with opposite phases. In one or more embodiments, instead of flipping one of the piezoelectric actuators 32 or 34 relative to the other, the polarity of the positive and negative wires powering the piezoelectric actuators are reversed to produce sound from each piezoelectric actuator having opposite phases relative to each other.

[0053] exist Figure 4, a cross-sectional view of a laminated glass structure 50 for a vehicle according to one or more embodiments of the present disclosure is shown, the laminated glass structure 50 including a pair of spaced apart piezoelectric actuators 52, 54 completely encapsulated within a polymer laminate material 56 disposed between a first glass panel 58 and a second glass panel 60. The first glass panel 58 includes an outer surface 62 (side 1) facing the external environment surrounding the vehicle and an inner surface 64 (side 2). The second glass panel 60 includes an inner surface 66 (side 3) facing the interior of the vehicle and an outer surface 68 (side 4). During assembly and lamination, a plurality of sheets of the polymer laminate material 56 are provided, wherein the piezoelectric actuators 52, 54 can be adhesively attached to selected surfaces of the sheet material, such that the piezoelectric actuators 52, 54 are respectively located at different vertical locations within the resulting laminate and on opposite sides of a centerline (C) extending longitudinally between the first glass panel 58 and the second glass panel 60.

[0054] Figure 5 A cross-sectional view of a laminated glass structure 70 is shown that includes a semi-rigid or rigid plastic layer 90 within a polymer laminate 76 between a first glass panel 78 and a second glass panel 80 at a centerline (C) to provide additional features, such as solar reflectivity, to the laminated glass structure in accordance with one or more embodiments of the present disclosure. An exemplary plastic layer 90 is a polyester, such as polyethylene terephthalate (PET), polycarbonate, or the like.

[0055] The first glass panel 78 includes an outer surface 82 (i.e., side 1) facing the exterior of the vehicle and an inner surface 84 (i.e., side 2), and the second glass panel 80 includes an inner surface 86 (i.e., side 3) facing the interior of the vehicle and an outer surface 88 (i.e., side 4). During assembly and lamination, a pair of piezoelectric actuators 72, 74 may be adhesively coupled to the plastic layer 90 at desired locations on opposite sides of the plastic layer 90 or on selected sheet surfaces of the polymer laminate material 76 prior to applying heat and pressure to form the laminated glass structure 70, such that the piezoelectric actuators 72, 74 are on opposite sides of the plastic layer 90. Although the piezoelectric actuators 72, 74 are disposed on opposite surfaces of the rigid plastic layer, it should be apparent that the piezoelectric actuators 72, 74 may be disposed on the same side, proximate the first glass panel 78 or proximate the second glass panel 80, and still produce sound, as long as the piezoelectric actuators 72, 74 are configured to produce sound in opposite phases as previously described. Plastic layer 90 may include a conductive metal coating (not shown) that may be patterned, such as by laser etching, to provide power to the actuator, or the laminated glass structure may include positive and negative wires that may be electrically coupled to the infotainment system to provide power.

[0056] Figure 6Depicted is a top-down view of an exemplary laminated glass structure including a pair of asymmetric piezoelectric actuators 96, 98 configured to produce sounds of opposite phase as described above, and a contour plot of the resulting total sound pressure (dB, scale on the right side of the figure) when actuated. Figure 7 It is along Figure 6 96, 98 provided in FIG. 1 . As shown in these figures, the sound produced by this dual asymmetric arrangement cancels at the symmetry plane between the pair of piezoelectric actuators. Applicants have found that in certain areas, the sound field is more uniform and louder than the sound field of a dual symmetric source (i.e., not asymmetric).

[0057] Figure 8 A top view of an exemplary laminated glass structure including four spaced apart asymmetric piezoelectric actuators 102, 104, 106, 108 is depicted, and a contour plot of the resulting total sound pressure (dB) of the four asymmetric piezoelectric actuators, such as may be desired for a panoramic roof glass panel covering four occupants of a vehicle. As shown, each of the four piezoelectric actuators 102, 104, 106, 108 is located above a location corresponding to each of the four occupants and is spaced relative to each other. Adjacent piezoelectric actuators include one piezoelectric actuator configured to generate sound in opposite phase relative to another piezoelectric actuator in the manner described above (pairs 102, 104; 102, 106; 104, 108 and 106, 108), while pairs of piezoelectric actuators at opposite corners (i.e., piezoelectric actuators diagonally opposite each other have the same phase, such as 102, 108 and 104, 106). As shown in the contour plots, the sound field from four asymmetric sources can be configured to cancel at the symmetry planes S1, S2 and be more uniform and louder in certain areas than the sound field from dual asymmetric sources (see Figure 5 for comparison).

[0058] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A laminated glass structure for a vehicle, comprising: a first glass panel including an inner surface and an outer surface facing the environment surrounding the vehicle; a second glass panel including an inner surface and an outer surface facing an interior of the vehicle; a laminate material between an inner surface of the first glass panel and an inner surface of the second glass panel effective to bond the first glass panel to the second glass panel; as well as At least one pair of spaced-apart piezoelectric actuators between the first glass panel and the second glass panel, wherein a thickness of each piezoelectric actuator is less than a thickness of the laminate, and wherein one of the piezoelectric actuators is at a different vertical position relative to the other piezoelectric actuator, and wherein the at least one pair of piezoelectric actuators is offset relative to a centerline extending longitudinally between the first glass panel and the second glass panel.

2. The laminated glass structure of claim 1, wherein one piezoelectric actuator is disposed on an inner surface of the first glass panel and another piezoelectric actuator is disposed on an inner surface of the second glass panel.

3. The laminated glass structure of claim 1, wherein each of the at least one pair of piezoelectric actuators is completely encapsulated within the laminate material.

4. The laminated glass structure of claim 1 , further comprising a plastic layer, the plastic layer comprising a first planar surface and a second planar surface and a sidewall extending between the first planar surface and the second planar surface, the sidewall defining a thickness of the plastic layer, wherein one piezoelectric actuator is disposed on the first planar surface of the plastic layer and another piezoelectric actuator is disposed on the second planar surface of the plastic layer.

5. The laminated glass structure of claim 4, wherein the plastic layer comprises polyethylene terephthalate.

6. The laminated glass structure of claim 1, wherein the laminating material comprises polyvinyl butyral resin or ethylene vinyl acetate.

7. The laminated glass structure of claim 1, wherein the laminate material has a thickness of about 0.3 millimeters to about 2 millimeters, and wherein each of the piezoelectric actuators has a thickness of less than 0.6 millimeters.

8. The laminated glass structure of claim 1, wherein the piezoelectric actuator is powered via an infotainment system to generate sound.

9. The laminated glass structure of claim 1, wherein the piezoelectric actuator comprises lead zirconium titanate, calcium titanate, barium titanate, lead titanate, or strontium titanate.

10. The laminated glass structure of claim 1, wherein the at least one pair of spaced apart piezoelectric actuators are at the same vertical position, and wherein a selected one of the at least one pair of piezoelectric actuators is configured to generate sound having an opposite phase relative to the other piezoelectric actuator.

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