Abstract:
A strain sensor apparatus for a rotatable shaft including a radiation emitter/receiver, a vibration element attached to the shaft and a radiation-reflective annulus surrounding the shaft and vibration element.
Abstract:
A strain sensor apparatus for a rotatable shaft including a radiation emitter/receiver, a vibration element attached to the shaft and a reflector that is positioned to reflect radiation onto the vibration element.
Abstract:
A process to form a laterally offset photodiode for an optically coupled resonator includes implanting a semiconductor substrate to form the laterally offset photodiode adjacent to the resonator. The resonator masks the implanting underneath the resonator when the semiconductor substrate is implanted. Also disclosed is an optically coupled resonator, a process for fabricating an optically coupled resonator, and a device including an optically coupled resonator having a laterally offset photodiode.
Abstract:
A pressure sensor includes a resonator element (14) mounted on an optical fibre ferrule (11) whereby light signals for maintaining the resonator in a state of oscillation and for returning a modulated signal to a remote station are coupled to the resonator. The resonator is located in an evacuated cavity and is mounted on a flexible diaphragm whereby pressure changes may be detected as changes in the resonant frequency.
Abstract:
A sensor comprises a beam, e.g. of silicon, which resonates at a frequency dependent on the force imposed on the beam. Light on a line induces resonance of the beam by means of the photothermal effect. The light reflected from the beam is amplitude modulated at the resonance frequency, and returns along the line. It is reflected by a semi-reflecting plane mirror onto a lens which focusses it onto a photodetector. The photodetector produces an output voltage modulated at the oscillation frequency, and is thus representative of the force imposed on beam 1.
Abstract:
Resonator measurement system having at least MEMS and/or NEMS, comprising: an optomechanical device comprising at least one resonating element at at least one resonance frequency of fr and at least one optical element whose optical index is sensitive to the displacement of the resonating element, excitation circuitry of exciting the resonating element at least at one operating frequency of fm, injection device for injecting a light beam whose intensity is modulated at frequency f1=fm+Δf in the optomechanical device, a photodetection device configured measure the intensity of a light beam coming out of the optomechanical device, the intensity of the measurement beam having at least one component at frequency Δf.
Abstract:
A resonator device 10 is disclosed. The resonator device may be used in a transducer or a sensor such as a pressure, force or acceleration sensor. The resonator device comprises a resonator 20 provided on a diaphragm 30. A cap 40 is provided which may be fusion bonded to the diaphragm 30 to enclose the resonator 20 and form a hermetically sealed package 10. The resonator device is excited by applying electromagnetic stimulation, such as infra-red or optical stimulation, which may be from a laser via a fibre 50. The resonator device may be interrogated by applying an electromagnetic signal into the optical cavity formed between the resonator 20 and the inside surface of the cap 40 to derive a frequency change of the resonator. As the resonator device incorporates a hermetically sealed package and is stimulated by electromagnetic radiation, it is robust and able to operate in harsh environments.
Abstract:
A strain sensor apparatus for a rotatable shaft including a radiation emitter/receiver, a vibration element attached to the shaft and a reflector that is positioned to reflect radiation onto the vibration element.
Abstract:
A device for measuring a vibration frequency of a mechanically vibrating string or rod, comprising a microwave transmitter for directing microwaves towards the vibrating string and a microwave receiver for receiving the microwaves amplitude modulated by the frequency of mechanical vibration. A member is arranged close to a vibration maximum of the vibrating string. The member is arranged on one side of the vibrating object and the microwave receiver is arranged on the other side thereof. The device is used for measuring temperature, pressure, torque, force or identity.
Abstract:
A device for measuring a vibration frequency of a mechanically vibrating string or rod, comprising a microwave transmitter for directing microwaves towards the vibrating string and a microwave receiver for receiving the microwaves amplitude modulated by the frequency of mechanical vibration. A member is arranged close to a vibration maximum of the vibrating string. The member is arranged on one side of the vibrating object and the microwave receiver is arranged on the other side thereof. The device is used for measuring temperature, pressure, torque, force or identity.