Abstract: The invention provides a planar component for interfacing an atmospheric pressure ionizer to a vacuum system. The component combines electrostatic optics and skimmers with an internal chamber that can be filled with a gas at a prescribed pressure and is fabricated by lithography, etching and bonding of silicon.

Abstract: This invention provides for a simple method of fabricating miniature electron multipliers, in an in-plane configuration suitable for use with miniature analytic instruments such as mass filters. The materials involved are predominantly silicon and compatible oxides, allowing the possibility of integration with a mass filter formed in a similar materials system. The materials are selected simultaneously to withstand high voltages and to enhance secondary electron emission. Fabrication is based on standard planar processing methods. These methods also allow the construction of an integrated set of bias resistors in a multi-electrode device, so that the device may be operated from a single high-voltage source.

Abstract: This invention describes the combination of an electrostatically operated valve and an electrically heated desorber, comprising a movable flap carrying a chemically adsorbing coating, suspended by an elastic element above an orifice in an insulated substrate. The device is constructed by planar processing. The flap can be deflected towards the substrate to block the flow of gas through the orifice by applying a voltage between the substrate and the flap. The coating provides an adsorbing surface for a volatile organic compound. The coating may be heated electrically, by applying an alternating voltage between the substrate and the flap, thermally desorbing any adsorbed chemical species. When combined with other similar valves in a stacked assembly, the device may be using in a chemical pre-concentrator with very low dead volume.

Abstract: A method of constructing a micro-engineered mass spectrometer from bonded silicon-on-insulator (BSOI) wafers is described with reference to a quadrupole spectrometer. The quadrupole geometry is achieved using two BSOI wafers (200), which are bonded together to form a monolithic block (410). Deep etched features and springs formed in the outer silicon layers are used to locate cylindrical metallic electrode rods (300). The precision of the assembly is determined by a combination of lithography and deep etching, and by the mechanical definition of the bonded silicon layers. Deep etched features formed in the inner silicon layers are used to define ion entrance and ion collection optics. Other features such as fluidic channels may be incorporated.

Abstract: This invention provides a method of accurately aligned, multilevel micro-contact-printing without the need for dedicated inking, alignment and stamping equipment. Die-sized micro-contact-printing engines are constructed from micromachined parts, which combine precision alignment features with stamper blocks supported on elastic suspensions. The stampers carry raised patterns, the alignment features mate with corresponding features on etched inkwells and substrates, and the pattern is transferred using a microactuator.

Abstract: An accelerometer or a seismometer using an in-plane suspension geometry having a suspension plate and at least one fixed capacitive plate. The suspension plate is formed from a single piece and includes an external frame, a pair of flexural elements, and an integrated proof mass between the flexures. The flexural elements allow the proof mass to move in the sensitive direction in the plane of suspension while restricting movement in all off-axis directions. Off-axis motion of the proof mass is minimized by the use of intermediate frames disbursed within and between the flexural elements. Intermediate frames can include motion stops to prevent further relative motion during overload conditions. The device can also include a dampening structure, such as a spring or gas structure that includes a trapezoidal piston and corresponding cylinder, to provide damping during non-powered states.

Abstract: A method of constructing a micro-engineered mass spectrometer from bonded silicon-on-insulator (BSOI) wafers is described with reference to a quadrupole spectrometer. The quadrupole geometry is achieved using two BSOI wafers (200), which are bonded together to form a monolithic block (410). Deep etched features and springs formed in the outer silicon layers are used to locate cylindrical metallic electrode rods (300). The precision of the assembly is determined by a combination of lithography and deep etching, and by the mechanical definition of the bonded silicon layers. Deep etched features formed in the inner silicon layers are used to define ion entrance and ion collection optics. Other features such as fluidic channels may be incorporated.

Abstract: A method of fabricating miniature quadrupole electrostatic mass filter has been previously described. The electrodes are metallised cylinders, mounted in grooves etched in oxidised silicon substrates, which are held apart at the correct spacing by cylindrical spacer rods. This invention concerns an ion source mounted on extensions of the spacer rods, which project beyond the mass filter. The ion source consists of a cold-cathode electron emitter, which emits electrons with energies sufficient to cause impact ionisation, and electrostatic optics suitable for coupling the ion flux into the mass filter. Methods of constructing a single self-aligned electron source and a similar dual source are described. Arrangements for mounting the electron source and the ion coupling lens so that the electron and ion beams travel at right angles to one another for efficient separation are described.

Abstract: A miniature, multi-element electrical connector fabricated using micro-electro-mechanical systems technology is described. Shaped elastic cantilever elements (12) are formed on the female part (11) by deposition of conducting material on a surface that has been previously shaped to define a localised contact area and a sloped entrance face. The cantilevers (12) are then undercut. A similar process is used to construct a sloping face on the male part (10) for easy insertion. An etching process is used to fabricate an interlocking alignment system (20, 21, 22) on the two parts. Erosion of a convex corner is used to form a tapered entrance (22) to this alignment system.

Abstract: A MEMS switching device including a first and second actuator and a switching member is described, the switching member being adapted to selectively provide a signal path between a first and second signal line. The selective provision of the signal path is effected by movement of a switching member from a first position to a second position, the movement of the switching member being effected by action of the first and second actuators thereon, such action resulting from a deformation of the actuators. In one embodiment of the invention, catch mechanisms link the switching member to the substrate in a first position, such that the switching member is maintained in this position when the actuation force is removed, and can be released by deformation of one actuator.

Abstract: A microengineered optical scanner based on a moving cantilevered dielectric waveguide is described. The waveguide is excited into resonant mechanical motion by a drive located at its root. Stress sensors detect the bending of the waveguide, allowing closed loop control of the motion. A moving image of the light emitted from the moving tip of the waveguide is created by a lens. The moving image acts as a scan line. Light back-scattered from a rough surface placed at the image plane is collected back into the waveguide by confocal imaging. The light collected in the cladding of the waveguide has higher numerical aperture than the light collected in the core. The cladding light is detected by a mode-stripping detector. Techniques for combining a cantilevered waveguide, a drive, motion sensors and a mode-stripping detector using microelectromechanical systems (MEMS) technology are described.

Abstract: A method of forming vertical knife-edge cold-cathode field emission electron sources with self-aligned gate electrodes and sub-micron electrode separations. The method exploits the enhancement of ion-beam erosion rates obtained in metals at oblique ion incidence, which allows the preferential removal of a metal layer at the convex edge of a mesa 2 to create a well-defined separation between the horizontal and vertical surfaces of the metal. The horizontal surface may be used as the gate and the vertical surface as the cathode in a vacuum triode structure. Electrical isolation is obtained by forming the mesa 2 in an insulating layer or substrate 1. Isolation may be improved by removing the insulating material in the vicinity of the metal edges. Field-induced electron emission from the cathode may be obtained at low voltage based on the enhancement of the electric field at the sharp tip of the cathode.

Abstract: This invention provides for a simple method of fabricating miniature electron multipliers, in an in-plane configuration suitable for use with miniature analytic instruments such as mass filters. The materials involved are predominantly silicon and compatible oxides, allowing the possibility of integration with a mass filter formed in a similar materials system. The materials are selected simultaneously to withstand high voltages and to. enhance secondary electron emission. Fabrication is based on standard planar processing methods. These methods also allow the construction of an integrated set of bias resistors in a multi-electrode device, so that the device may be operated from a single high-voltage source.

Abstract: An accelerometer or a seismometer using an in-plane suspension geometry having a suspension plate and at least one fixed capacitive plate. The suspension plate is formed from a single piece and includes an external frame, a pair of flexural elements, and an integrated proof mass between the flexures. The flexural elements allow the proof mass to move in the sensitive direction in the plane of suspension while restricting movement in all off-axis directions. Off-axis motion of the proof mass is minimized by the use of intermediate frames disbursed within and between the flexural elements. Intermediate frames can include motion stops to prevent further relative motion during overload conditions. The device can also include a dampening structure, such as a spring or gas structure that includes a trapezoidal piston and corresponding cylinder, to provide damping during non-powered states.

Abstract: A method of fabricating miniature quadrupole electrostatic mass filter has been previously described. The electrodes are metallised cylinders, mounted in grooves etched in oxidised silicon substrates, which are held apart at the correct spacing by cylindrical spacer rods. This invention concerns an ion source mounted on extensions of the spacer rods, which project beyond the mass filter. The ion source consists of a cold-cathode electron emitter, which emits electrons with energies sufficient to cause impact ionisation, and electrostatic optics suitable for coupling the ion flux into the mass filter. Methods of constructing a single self-aligned electron source and a similar dual source are described. Arrangements for mounting the electron source and the ion coupling lens so that the electron and ion beams travel at right angles to one another for efficient separation are described.

Abstract: This invention concerns a method of forming vertical knife-edge cold-cathode field emission electron sources with self-aligned gate electrodes and sub-micron electrode separations. The method exploits the enhancement of ion-beam erosion rates obtained in metals at oblique ion incidence, which allows the preferential removal of a metal layer at the convex edge of a mesa 2 to create a well-defined separation between the horizontal and vertical surfaces of the metal. The horizontal surface may be used as the gate and the vertical surface as the cathode in a vacuum triode structure. Electrical isolation is obtained by forming the mesa 2 in an insulating layer or substrate 1. Isolation may be improved by removing the insulating material in the vicinity of the metal edges. Field-induced electron emission from the cathode may be obtained at low voltage based on the enhancement of the electric field at the sharp tip of the cathode.

Abstract: A wavelength tunable optical filter 14 and a method of making the same. The optical filter 14 comprising two back-to-back Fabry-Perot optical cavities 30 & 40 comprising a fixed mirror 31 common to both cavities with parallel displaceable mirrors 32 & 42 located one on each side of the fixed mirror 31 to adjust the overall known length of the respective cavities. One optical cavity may have greater length than the other optical cavity.

Abstract: An inflatable seal system in a tool having opposed parts which are relatively movable together with the inflatable seal system therebetween. The inflatable seal system comprising a longitudinally extending seal cavity and a seal extending longitudinally along the seal cavity. The seal comprises an inflatable portion and an abutment portion for sealingly abutting against an opposing surface, wherein the inflatable portion remains in the seal cavity when the seal is deflated.

Abstract: An inflatable seal system in a tool having opposed parts which are relatively moveable together with the inflatable seal system therebetween. The inflatable seal system comprising a longitudinally extending seal cavity and a seal extending longitudinally along the seal cavity. The seal comprises an inflatable portion and an abutment portion for sealingly abutting against an opposing surface, wherein the inflatable portion remains in the seal cavity when the seal is deflated.

Abstract: A quadrupole mass spectrometer comprises an ion source (20), a mass filter (22) and an ion collector (24). The ion source comprises an array (30) of quantum wires. The mass filter comprises four glass fibres (32) coated with nickel and the ion collector is an a electrode connected to an integrated complementary metal oxide semiconductor temperature compensated integrated amplifier.