Abstract: A control circuit for an electrostatic transducer including: an audio signal input, a detector configured to detect a current or charge signal from the electrostatic transducer. The detector is configured to produce an audio output signal varying at audio frequencies. A transform circuit is configured to transform the audio output signal to produce a feedback signal. A comparator is configured to compare an input audio signal at the audio signal input to the feedback signal to produce an error signal. A controller is configured to input a control signal to the electrostatic transducer, the control signal responsive to the error signal. The control signal is configured to control acoustic transparency of the electrostatic transducer, from outside space through through-holes of the first electrode, across the membrane and through through-holes of the second electrode.

Abstract: Monitoring time-dependent displacement of a membrane in an electrostatic acoustic device. An oscillator is configured to produce a probe signal varying at radio frequency. The probe signal is symmetrically coupled into the first and second electrodes. DC bias voltages are symmetrically applied to the first and second electrodes. A voltage signal from the membrane is sensed and input at a high pass filter input. A multiplier is configured to input the filtered signal modulated at radio frequency and portion of the probe signal. The multiplier is configured to output a multiplied signal which is demodulated to produce therefrom an audio output signal responsive to the time-dependent displacement of the membrane.

Abstract: A control circuit for an electrostatic transducer including: an audio signal input, a detector configured to detect a current or charge signal from the electrostatic transducer. The detector is configured to produce an audio output signal varying at audio frequencies. A transform circuit is configured to transform the audio output signal to produce a feedback signal. A comparator is configured to compare an input audio signal at the audio signal input to the feedback signal to produce an error signal. A controller is configured to input a control signal to the electrostatic transducer, the control signal responsive to the error signal. The control signal is configured to control acoustic transparency of the electrostatic transducer, from outside space through through-holes of the first electrode, across the membrane and through through-holes of the second electrode.

Abstract: An electrostatic transducer including a membrane, a first electrode and a second electrode. The first electrode is disposed parallel to the membrane. The membrane is configured to respond mechanically to a varying first electric field in accordance with respective electric potentials applied between the first electrode and the membrane. The second electrode is disposed parallel to the membrane opposite from the first electrode. The membrane is configured to respond mechanically to a varying second electric field in accordance with respective electric potentials between the second electrode and the membrane. The first and second electrodes have through holes configured for acoustic transmission to and from the membrane.

Abstract: An acoustic device including a membrane having an edge. A membrane support is attached to the edge of the membrane. A central region of the membrane is unsupported by the support. A first electrode and the membrane support are manufactured as a single element. The first electrode is disposed parallel to the membrane. The membrane is configured to respond acoustically to a varying first electric field emanating from the first electrode when a varying first voltage is applied to the first electrode. A coating is deposited on a surface of the first electrode facing the membrane.

Abstract: A membrane hetero-structure includes a polymer layer and a single-layer or multi-layer graphene sheet disposed on the polymer layer. The membrane hetero-structure is tensioned across a frame having an opening such that both the polymer layer and the graphene sheet extend across the opening. An optional rigid member is provided in a center of the membrane to be spaced apart from edges of the opening. The assembly of the frame and membrane hetero-structure forms an electrostatically driven micro-electro-mechanical system (MEMS) or sound generation and recording apparatus. In one instance, when a voltage signal is applied between an electrode layer parallel to the membrane and contacts on the frame that are electrically connected to the graphene sheet, the membrane hetero-structure is actuated.

Abstract: A membrane hetero-structure includes a polymer layer and a single-layer or multi-layer graphene sheet disposed on the polymer layer. The membrane hetero-structure is tensioned across a frame having an opening such that both the polymer layer and the graphene sheet extend across the opening. An optional rigid member is provided in a center of the membrane to be spaced apart from edges of the opening. The assembly of the frame and membrane hetero-structure forms an electrostatically driven micro-electro-mechanical system (MEMS) or sound generation and recording apparatus. In one instance, when a voltage signal is applied between an electrode layer parallel to the membrane and contacts on the frame that are electrically connected to the graphene sheet, the membrane hetero-structure is actuated.

Abstract: A method for making a film of core-shell nanoparticles generally uniformly arranged on a substrate uses atomic layer deposition (ALD) to form the shells. The nanoparticle cores are placed in a solution containing a polymer having an end group for attachment to the cores. The solution is then applied to a substrate and allowed to dry, resulting in the nanoparticle cores being uniformly arranged by the attached polymer chains. ALD is then used to grow the shell material on the cores, using two precursors for the shell material that are non-reactive with the polymer. The polymer chains also form between the cores and the substrate surface, so the ALD forms shell material completely surrounding the cores. The uniformly arranged core-shell nanoparticles can be used as an etch mask to etch the substrate.

Abstract: A method for making a film of core-shell nanoparticles generally uniformly arranged on a substrate uses atomic layer deposition (ALD) to form the shells. The nanoparticle cores are placed in a solution containing a polymer having an end group for attachment to the cores. The solution is then applied to a substrate and allowed to dry, resulting in the nanoparticle cores being uniformly arranged by the attached polymer chains. ALD is then used to grow the shell material on the cores, using two precursors for the shell material that are non-reactive with the polymer. The polymer chains also form between the cores and the substrate surface, so the ALD forms shell material completely surrounding the cores. The uniformly arranged core-shell nanoparticles can be used as an etch mask to etch the substrate.

Abstract: A method using directed self-assembly of BCPs enables the making of a master disk for nanoimprinting magnetic recording disks that have patterned data islands and patterned binary encoded nondata marks. The method uses guided self-assembly of a BCP to form patterns of sets of radial lines and circumferential gaps of one of the BCP components, which can be used as an etch mask to make the master disk. The sets of radial lines and circumferential gaps can be patterned so as to encode binary numbers. The pattern is replicated as binary encoded nondata marks into the nanoimprinted disks, with the marks functioning as binary numbers for data sector numbers and/or servo sector numbers. If the disks also use a chevron servo pattern, the binary numbers can function to identify groups of tracks associated with the chevron servo pattern.

Abstract: A patterned perpendicular magnetic recording disk with discrete data islands of recording layer (RL) material includes a substrate, a patterned exchange bridge layer of magnetic material between the substrate and the islands, and an optional exchange-coupling control layer (CCL) between the exchange bridge layer and the islands. The exchange bridge layer has patterned pedestals below the islands. The exchange bridge layer controls exchange interactions between the RLs in adjacent islands to compensate the dipolar fields between islands, and the pedestals concentrate the flux from the write head. The disk may include a soft underlayer (SUL) of soft magnetically permeable material on the substrate and a nonmagnetic exchange break layer (EBL) on the SUL between the SUL and the exchange bridge layer. In a thermally-assisted recording (TAR) disk a heat sink layer may be located below the exchange bridge layer and the SUL may be optional.

Abstract: A method for making a master disk for nanoimprinting patterned-media magnetic recording disks has patterns for both the data islands and the nondata regions. The method uses guided self-assembly of a block copolymer (BCP) to form patterns of generally radial lines and/or generally concentric rings as well as patterns of gap regions of one of the BCP components. The pattern of lines and/or rings have the BCP components aligned as lamellae perpendicular to the substrate, while the pattern of gap regions has the BCP components aligned as lamellae parallel to the substrate. One of the BCP components is removed, leaving the other BCP component as an etch mask to fabricate either the final master disk or two separate molds that are then used to fabricate the master disk.

Abstract: An embodiment of the invention provides an apparatus that includes: a storage media including a patterned structure, the patterned structure including a first groove, a first stopper in the first groove, wherein the first stopper is configured to interrupt the flow of gas in a section within the first groove.

Abstract: A method using directed self-assembly of BCPs enables the making of a master disk for nanoimprinting magnetic recording disks that have patterned data islands and patterned binary encoded nondata marks. The method uses guided self-assembly of a BCP to form patterns of sets of radial lines and circumferential gaps of one of the BCP components, which can be used as an etch mask to make the master disk. The sets of radial lines and circumferential gaps can be patterned so as to encode binary numbers. The pattern is replicated as binary encoded nondata marks into the nanoimprinted disks, with the marks functioning as binary numbers for data sector numbers and/or servo sector numbers. If the disks also use a chevron servo pattern, the binary numbers can function to identify groups of tracks associated with the chevron servo pattern.

Abstract: A method for making a master disk for nanoimprinting patterned-media magnetic recording disks has patterns for both the data islands and the nondata regions. The method uses guided self-assembly of a block copolymer (BCP) to form patterns of generally radial lines and/or generally concentric rings as well as patterns of gap regions of one of the BCP components. The pattern of lines and/or rings have the BCP components aligned as lamellae perpendicular to the substrate, while the pattern of gap regions has the BCP components aligned as lamellae parallel to the substrate. One of the BCP components is removed, leaving the other BCP component as an etch mask to fabricate either the final master disk or two separate molds that are then used to fabricate the master disk.

Abstract: A patterned perpendicular magnetic recording disk has a pre-patterned disk substrate with pillars and trenches arranged in data regions and servo regions. In the data regions, the height of the data pillars is equal to or greater than the spacing between the data pillars, while in the servo regions the height of the servo pillars is less than the spacing between the servo pillars. A magnetic recording material with perpendicular magnetic anisotropy is deposited over the entire disk substrate, which results in magnetic material on the tops of the data pillars and servo pillars and in the servo trenches. The material in the data trenches is either nonmagnetic or discontinuous. After the application of a high DC magnetic field in one perpendicular direction and a low DC magnetic field in the opposite direction, the resulting disk has patterned servo sectors with servo pillars all magnetized in the same perpendicular direction and servo trenches magnetized in the opposite perpendicular direction.

Abstract: An embodiment of the invention provides an apparatus that includes: a storage media including a patterned structure, the patterned structure including a first groove, a first stopper in the first groove, wherein the first stopper is configured to interrupt the flow of gas in a section within the first groove.

Abstract: A patterned perpendicular magnetic recording disk with discrete data islands of recording layer (RL) material includes a substrate, a patterned exchange bridge layer of magnetic material between the substrate and the islands, and an optional exchange-coupling control layer (CCL) between the exchange bridge layer and the islands. The exchange bridge layer has patterned pedestals below the islands. The exchange bridge layer controls exchange interactions between the RLs in adjacent islands to compensate the dipolar fields between islands, and the pedestals concentrate the flux from the write head. The disk may include a soft underlayer (SUL) of soft magnetically permeable material on the substrate and a nonmagnetic exchange break layer (EBL) on the SUL between the SUL and the exchange bridge layer. In a thermally-assisted recording (TAR) disk a heat sink layer may be located below the exchange bridge layer and the SUL may be optional.

Abstract: A thermally-assisted recording (TAR) patterned-media magnetic recording disk drive has a perpendicular patterned-media disk with multilevel data islands and a laser capable of supplying multiple levels of output power to a near-field transducer (NFT). If there are only two cells in each island, each island is formed of an upper cell of magnetic material with a coercivity HC1 and a Curie temperature TC1, a lower cell of magnetic material with a coercivity HC2 and a Curie temperature TC2 greater than TC1, and a nonmagnetic spacer layer between the two cells. Each cell is formed of high-anisotropy material so as to have an anisotropy field greater than the magnetic write field. The TAR laser is capable of supplying at least two levels of output power to the NFT to allow the islands to be heated to two distinct temperatures so that the two cells in an island can be written so as to have either the same or opposite magnetizations.

Abstract: A patterned perpendicular magnetic recording disk has a pre-patterned disk substrate with pillars and trenches arranged in data regions and servo regions. In the data regions, the height of the data pillars is equal to or greater than the spacing between the data pillars, while in the servo regions the height of the servo pillars is less than the spacing between the servo pillars. A magnetic recording material with perpendicular magnetic anisotropy is deposited over the entire disk substrate, which results in magnetic material on the tops of the data pillars and servo pillars and in the servo trenches. The material in the data trenches is either nonmagnetic or discontinuous. After the application of a high DC magnetic field in one perpendicular direction and a low DC magnetic field in the opposite direction, the resulting disk has patterned servo sectors with servo pillars all magnetized in the same perpendicular direction and servo trenches magnetized in the opposite perpendicular direction.