Adjustable sound panel with electroactive actuators

A panel that can change its stiffness and/or surface roughness and thereby its sound quality is provided. The panel includes a layer having an outer surface and an inner surface oppositely disposed from the outer surface. The panel can also include an electroactive actuator that is operable to change its shape when a voltage is applied thereto. The change in shape of the electroactive actuator results in a change in stiffness and/or surface roughness of the panel and therefore a change in the panel's acoustic characteristics. In some instances, the electroactive actuator is at least partially within the panel and upon changing of its shape results in a change in the roughness of a surface that faces a sound source. In other instances, the activation of the electroactive actuator results in an increase in stiffness of the panel.

FIELD OF THE INVENTION

The present invention is directed to a sound panel, and more particularly to a sound panel that can be adjusted.

BACKGROUND OF THE INVENTION

Sound quality can be defined as the physical pleasure or fatigue experienced by a listener and is typically characterized in a live setting by the skill of musicians, tonal quality of their musical instruments and the physical traits of the venue. Related to effecting sound quality, architectural acoustics is the science of controlling sound within buildings and can be broken into four general areas: (1) analysis of the exterior envelope of the building; (2) analysis of noise transmission from one building space to another; (3) analysis of the surfaces of interior spaces of the building; and (4) analysis of mechanical equipment noise generated within the building. Motor vehicles, military vehicles, aircraft and the like can use a similar approach by analyzing the exterior envelope of the vehicle, the noise transmitted from one space of the vehicle to another space, the characteristics of the surfaces of the interior spaces of the vehicle and noise generated by mechanical equipment of the vehicle. However, a motor vehicle, military vehicle, aircraft and the like has an additional complication of having a mobile interior space that is exposed to a wide range of noise scenarios, some changing within a given trip, mission and/or ride in the vehicle.

Looking particularly at the interior space within such vehicles, one method to control sound therein is to use fabric to cover interior surfaces in order to absorb the sound. However, fabric surfaces can be difficult to clean and it can be desirable for a surface to reflect sound rather than absorb it. Therefore, a panel or a surface on a panel that can change or alter its acoustic characteristics as a function of time, noise scenario and/or occupant instruction would be desirable.

SUMMARY OF THE INVENTION

A panel that can change its stiffness and/or surface roughness and thereby its sound quality is provided. The panel includes a layer having an outer surface and an inner surface oppositely disposed from the outer surface. The panel can also include an electroactive actuator that is operable to change its shape when a voltage is applied thereto. The change in shape of the electroactive actuator results in a change in stiffness and/or surface roughness of the panel and therefore a change in the panel's acoustic characteristics. In some instances, the electroactive actuator is at least partially within the panel and upon changing of its shape results in a change in the roughness of a surface that faces a sound source. In other instances, the activation of the electroactive actuator results in an increase in stiffness of the panel.

The panel can be made from one layer, or in the alternative can be made from more than one layer. For example, the panel can be made from an outer layer having a surface that faces a sound source, with an oppositely disposed surface being in contact with an inner layer that has an electroactive actuator at least partially therein. Upon activation of the electroactive actuator and its change in shape, the surface roughness and/or stiffness of the outer layer is altered. In addition, a panel can include an outer layer supported by a substrate, the substrate having the outer layer on one surface and the inner layer with the electroactive actuator therein on an opposing surface. Similar to the one layer and two layer panels described above, activation of the electroactive actuator and change in its shape results in a change in the surface roughness and/or stiffness of the outer layer.

In some instances, the electroactive actuator can be an electroactive polymer, the electroactive polymer being a dielectric electroactive polymer or an ionic electroactive polymer. An electrical source of power can also be included which can provide a voltage to the electroactive actuator. In addition, the electroactive actuator at least partially within a layer can be a plurality of electroactive actuators that are electrically connected to the electrical source of power and are spaced apart at predetermined distances from each other.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed generally to a panel with acoustic characteristics that can be altered. As such the panel has utility as a component for improving the sound quality of a vehicle.

The panel disclosed herein includes a layer that has at least one electroactive actuator at least partially therein. The panel can include a single layer where the electroactive actuator is at least partially therein, activation of the electroactive actuator resulting in a change of the shape thereof and a subsequent change in the surface roughness and/or stiffness of the layer. In the alternative, the panel can be made from two layers, an outer layer having a surface that faces a sound source and an inner layer oppositely disposed therefrom, the inner layer having an electroactive actuator at least partially therein. Similar to the one layer panel, activation of the electroactive actuator results in a change of the shape thereof and a subsequent change in the surface roughness and/or stiffness of the outer layer and thus the panel. Another illustrative example is provided wherein a panel is made from three layers; an outer layer that has a surface that faces a sound source, a substrate that provides backing and support to the outer layer and a third layer that has an electroactive actuator at least partially therein. Activation of the electroactive actuator that is at least partially within the third layer causes a change of the shape thereof and thus a subsequent change in the surface roughness and/or stiffness of the outer layer.

It is appreciated that the electroactive actuator can be an electroactive polymer that is made from a dielectric electroactive polymer or an ionic electroactive polymer. If a dielectric electroactive polymer is used, the polymer can be made from silicones and acrylic elastomers.

Turning now toFIGS. 1A-1D, an embodiment of the panel disclosed herein is shown generally at reference numeral20. The panel20includes a layer120having an outer surface122that faces a sound source S and an inner surface124oppositely disposed therefrom. Optionally included between the surface122and the surface124can be a fill material126. In some instances, the fill material126can be a foam material. At least partially within the layer120is an electroactive actuator200that is electrically connected to a power supply300via an electrical lead210, or in the alternative using a plurality of electrical leads210. In some instances, a plurality of electroactive actuators200that are spaced apart by predetermined distances can be provided. As shown inFIG. 1B, when the power supply300is off, the electroactive actuators200exist in their natural state. In contrast,FIG. 1Cillustrates the activation of the electroactive actuators200as illustrated by reference numeral200′ wherein the electroactive actuator200expands in a direction generally perpendicular to the outer surface122. In the alternative,FIG. 1Dillustrates the activation of the electroactive actuators200as illustrated by reference numeral200″ wherein the electroactive actuator200expands in a direction generally parallel to the outer surface122. As illustrated inFIGS. 1C and 1D, the activation of the electroactive actuator200as represented by reference numerals200′ and200″, and the change in shape thereof, can result in a change in the shape and/or surface roughness of the panel as shown inFIG. 1Cor a change in the shape and/or stiffness of the panel as best illustrated inFIG. 1D. It is appreciated that the panel20can have a plurality of electroactive actuators with a given number that expand in a direction generally perpendicular to the outer surface122and a given number that expand in a direction generally parallel to the outer surface122. In addition, the panel20can have a plurality of electroactive actuators that expand in a variety of different directions relative to the outer surface122. Furthermore, it may or may not be required or necessary for the voltage to remain applied to the electroactive actuator200in order for the actuator to maintain its expanded shape.

Although not shown, a second layer can be placed on either side of the layer120, that is either on the side facing the sound source S or on the side opposite thereof. In this manner, the panel120can alter its sound quality by applying a voltage to an electroactive actuator within the panel.

Turning now toFIGS. 2A-2D, another embodiment of a panel is shown generally at reference numeral30. In this embodiment, the panel30is made from an outer layer160and an inner layer130. The outer layer160has an outer surface162that faces the sound source S and an oppositely disposed surface164that faces the second layer130. The inner layer130has a surface132that is adjacent to the surface164of the outer layer160and a surface134oppositely disposed surface132. Optionally included between the surface132and the surface134can be a fill material136. Located at least partially within the layer130is the electroactive actuator200, or in the alternative the plurality of electroactive actuators200that are electrically connected to the power supply300using the electrical lead210. As shown inFIGS. 2C and 2D, activation of the electroactive activators200that are at least partially within the inner layer130results in a change in their shape as illustrated by reference numerals200′ and200″. The change in shaper thereby affords for a change in the surface roughness and/or stiffness of the second layer130and also the panel30. Although the activated electroactive actuators200′ and200″ illustrate the electroactive actuator200changing its shape in two different directions, it is appreciated that a change in shape in other directions can be provided and included within the scope of this disclosure.

Turning now toFIGS. 3A-3D, yet another embodiment of a panel is shown generally at reference numeral40. In this embodiment, a substrate180is present between the outer layer160and a third layer140. The third layer140is similar to the second layer130illustrated inFIGS. 2A-2Dand includes the electroactive actuator200that is at least partially therewithin and optionally has a fill material146between surfaces142and144. Similar to the previous discussion, the outer layer160has the outer surface162that faces the sound source S. Adjacent to the oppositely disposed surface164is the substrate180with the third layer140adjacent thereto. Similar to the discussion above, activation of the electroactive actuator200as illustrated inFIGS. 3C and 3Dresults in a change in their shape illustratively shown at200′ and200″, and thus a corresponding change in the surface roughness (not shown) and/or stiffness of the layer140and panel40.

Also shown inFIG. 3Dis a second sound source S′ adjacent to the third layer140. It is appreciated that activation of the electroactive actuator(s)200as discussed above can effect how sound from the second sound source S′ is reflected, transmitted and/or absorbed by the panel.

A change in the surface roughness and stiffness of the panel will alter how sound waves will be reflected, absorbed, transmitted and the like by/through the panel. In this manner, the reflection, absorption, transmittance and the like of sound waves that impact the panel from whichever side can be altered.

In use, a panel as described above can have its sound quality characteristics altered during assembly of the motor vehicle, during use of the motor vehicle, and/or during maintenance checkups of the motor vehicle. Thus it is appreciated that control of the activation of the electroactive actuator(s) and thus the surface roughness and/or stiffness of such a panel may or may not be adjustable by an occupant of a vehicle. However, it is appreciated that during different noise scenarios, e.g. when a motor vehicle is traveling down a road, it can be desirable for an occupant to have the ability to change the sound quality of the panel and thereby improve the sound quality of music being played within the vehicle, decrease the road noise experienced by an occupant within the vehicle and the like.

The invention is not restricted to the illustrative examples described above. The examples are not intended as limitations on the scope of the invention. Methods, apparatus, compositions and the like described herein are exemplary and not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art. The scope of the invention is defined by the scope of the claims.