A suspended nanotube film (or films) producing sound by means of the thermoacoustic (TA) effect is encapsulated between two plates, at least one of which vibrates, to enhance sound generation efficiency and protect the film. To avoid the oxidation of carbon nanotubes at elevated temperatures and reduce the thermal inertia of surrounding medium the enclosure is filled with inert gas (preferably with high heat capacity ratio, =C.sub.p/C.sub.v, and low heat capacity, C.sub.p). To generate sound directly as the first harmonic of applied audio signal without use of an energy consuming dc biasing, an audio signal modulated carrier frequency at much higher frequency is used to provide power input. Various other inventive means are described to provide enhanced projected sound intensity, increased projector efficiency, and lengthened projector life, like the use of infrared reflecting coatings and particles on the projector plates, non-parallel sheet alignment in sheet stacks, and cooling means on one projector side.

Embodiments disclosed herein include a device with an integrated acoustics function that includes a patterned touch screen cover, an acoustic thin film, a plurality of electrodes, and a substrate. In some embodiments, the substrate is coupled to the acoustic thin film and reduces heat loss from the acoustic thin film through the substrate. The acoustic thin film may be coupled to the patterned touch screen cover and conducts an oscillating electrical current provided by the plurality of electrodes, thereby acting as a nano-scale acoustic generator. In still some embodiments, the patterned touch screen cover provides an array of microspeakers and a viewing area, where the array of microspeakers is disposed around a perimeter of the patterned touch screen cover.

A system for suppressing signal harmonic distortion caused by a main signal processing device provides processing for an electrical signal containing sine components of multiple frequencies. A post-processor reduces the amplitude of each frequency, relative to other frequencies, as the frequency increases, thus suppressing harmonics, which have higher frequencies than their respective elementary signals. To compensate for frequency distortion caused by the differential frequency suppression in the post-processing stage, a pre-processor provided upstream of the main signal processing device provides frequency-dependent signal processing having a generally opposite effect to that of the post-processor, increasing the amplitude of each frequency of the signal passing through the pre-processor, relative to other frequencies, as the frequency increases. The resulting output signal thus has substantially the same frequency spectrum as the original signal while distortion-causing harmonics are reduced or eliminated.

A method for making a diaphragm is disclosed. The method includes the steps of: providing a carbon nanotube film structure; soaking the carbon nanotube film structure with a polymer; and carbonizing the carbon nanotube film structure infiltrated in the polymer, the polymer being carbonized to an amorphous carbon structure.

The present invention provides a method for manufacturing a thermal bimorph diaphragm and a MEMS speaker with thermal bimorphs, wherein the method comprises the steps of: thermally oxidizing a substrate to obtain an insulating layer thereon and providing a metal layer on the insulating layer; providing a sacrificial layer on the metal layer; providing a first thermal bimorph layer on the sacrificial layer; providing a second thermal bimorph layer on the first thermal bimorph layer; providing a metal connecting layer at the positions on the metal layer where the sacrificial layer is not provided; forming corresponding back holes on the substrate and the insulating layer and releasing the sacrificial layer; forming the thermal bimorph diaphragm which is warped with the first thermal bimorph layer and the second thermal bimorph layer after the sacrificial layer is released.

The disclosure relates to an earphone. The earphone includes a housing, a first speaker located in the housing and configured to play a first sound in a high frequency range, and a second speaker located in the housing and configured to play a second sound in a low frequency range or a middle frequency range. The first speaker includes a thermoacoustic device unit including a sound wave generator including carbon nanotube structure. The second speaker is an electric loudspeaker, electromagnetic speaker, or capacitive speaker.

A condenser microphone and a method for discriminates a first segment and a second segment in a spoken sound, is provided by using carbon nanotube bundles as capacitor materials. Such capacitor capacitance varies due to the quantum thermal mechanism of CNTs when a spoken sound containing vowel segments and consonant segments passes through the CNTs, so that the vowel segments and the consonant segments can be detected and separated.

A transducer comprising a primary element comprising a magnet configured to provide a magnetic field within a magnetic zone, the magnetic field extending in a magnetic field direction; a secondary element comprising a first graphene sheet located within the magnetic zone; a static portion; and a rotating portion configured to rotate about an axis of rotation relative to the static portion. The rotating portion comprises a first one of a set comprising the primary element and the secondary element; and wherein the static portion comprises a second one of the set; and wherein an axis of rotation of the rotating portion is such that: in a first position of the static portion relative to the rotating portion, the first graphene sheet lies in a first plane that is parallel to the magnetic field direction; and in a second position of the static portion relative to the rotating portion, the first graphene sheet lies in an offset plane that is at an angle to the first plane about the axis of rotation. On deployment of the transducer in a first mode, movement of the rotating portion relative to the static portion causes an electrical potential to be generated in the first graphene sheet thereby converting rotational kinetic energy into electrical potential; and/or on deployment of the transducer in a second mode, electrical potential in the first graphene sheet causes rotation of the rotating portion relative to the static portion thereby converting electrical potential into rotational kinetic energy.

An underwater sound generation device may be used for effective control of algae and other microorganisms in ponds and lakes. The sound projector may comprise a thermoacoustic sound transducer and an electronic unit for controlling the operation of the projector. The thermoacoustic projector may include a freestanding carbon nanotube (CNT) film encapsulated between two vibrating plates. The inert gas filled thin acoustical cavity provides a piston-type displacement of the plates and supports a high-temperature operation. A power supply driver, controlling the operation of the sound radiating system, may include a pulse generator, high-power switch amplifier, and a cable, connecting the projector with an electronic driver. The sound control system may provide an omnidirectional sound pressure level in a wide frequency range to affect the algae growth ecosystem over large distances.

An apparatus, method and computer program is described including: a driver for driving a membrane of a gas-retaining chamber to induce vibrations in the membrane in a first mode of operation, wherein said membrane is configured to surround at least part of a device; and an activator for activating a rapid expander in a second mode of operation, wherein the expander comprises an expandable foam that is configured to inflate said chamber in response to an activation signal.