Abstract:
In order to reduce the exposure of a detector surface 180 of a photo-multiplier 160 to stray charged particles, an off-axis structure is interposed between the resonant structure and the detector surface of the photo-multiplier. By providing the off-axis structure with at least one reflective surface, photons are reflected toward the detector surface of the photo-multiplier while at the same time absorbing stray charged particles. Stray particles may be absorbed by the reflective surface or by any other part of the off-axis structure. The off-axis structure may additionally be provided with an electrical bias and/or an absorbing coating for absorbing stray charged particles.
Abstract:
An IR limiting device for a detector that is based on a micro-optomechanical cantilever array is disclosed. In the normal state, each microcantilever device in the array behaves like a mirror that reflects the infrared signal to the detector. The microcantilever device absorbs radiation outside the desired infrared region. When the radiation is stronger than a predetermined threshold, the microcantilever device bends as a result of thermo-mechanical forces, and it reflects the signal away from the detector, thereby limiting the radiation. The advantage of such a system is that each pixel in the detector can be addressed individually, and the limiting is localized.
Abstract:
A non-circular, mechanically variable optical attenuator using a pair of specially constructed polarizing elements with means enabling a gradual transition from un-crossed polarization vector fields to crossed polarization vector fields using a linear motion with respect to one another. The polarizing elements whose polarization axis varies with spatial position on the element have a polarization vector field that is a function of position on the element. Specifically, the two polarizing elements have a defined orientation of polarization axes or vectors on the polarization vector fields that vary with spatial location on the polarizing element such that when aligned light passes, and when the polarization axes are crossed, light is attenuated. The present attenuator has a practical application for dimmable mirrors or windows by providing a variable optical attenuator that is purely mechanical and non-circular in shape. Dimming of the mirror or window is controlled by gradually sliding one such special polarizer with respect to the other.
Abstract:
A solar filter assembly combines a high-precision Fabry-Perot etalon with a variety of conditioning filters judiciously selected to effectively block completely all radiation except for the spectral line of interest. In addition, a tuning mechanism is provided to precisely control the peak frequency of the filter's output by varying the optical length of the etalon's cavity.
Abstract:
A handheld fluorescence detector that includes a handheld data processing system and a UV light source connected to the data processing system is disclosed. The UV light source illuminates an object to be scanned with light having a UV illumination wavelength. A safety mechanism inhibits the light from the UV light source from reaching an eye of a person in the vicinity of the UV light source at an intensity that would damage the eye. A fluorescence detector senses fluorescent light generated by the object in response to the illumination. The fluorescence detection can utilize a photodetector or a human observer. The detector can be included in a cellular telephone or PDA. Safety mechanisms that utilize baffles or total internal reflection to protect the user are described. In addition, interlock mechanisms that prevent the UV light source from being activated when no object is present can be incorporated.
Abstract:
A photo-sensing device includes a light emitting part, a light receiving part, and a housing. The light emitting part emitting a beam of light to the light receiving part, and the housing contains the light emitting part and the light receiving part. The housing includes at least an opening, and the opening is covered by an insulation component to prevent electrostatic charges from damaging the photo-sensing device.
Abstract:
An IR limiting device for a detector that is based on a micro-optomechanical cantilever array is disclosed. In the normal state, each microcantilever device in the array behaves like a mirror that reflects the infrared signal to the detector. The microcantilever device absorbs radiation outside the desired infrared region. When the radiation is stronger than a predetermined threshold, the microcantilever device bends as a result of thermo-mechanical forces, and it reflects the signal away from the detector, thereby limiting the radiation. The advantage of such a system is that each pixel in the detector can be addressed individually, and the limiting is localized.
Abstract:
An auto darkening eye protection device comprising a shutter assembly and a control circuit. The shutter assembly is adjustable between a light state and a dark state. The control circuit comprises a sensing circuit, a weld detect circuit, a positive voltage generator, and a negative voltage generator. The sensing circuit senses incident light and provides an output indicative of the incident light. The weld detect circuit receives the output of the sensing circuit, and enables a dark state drive signal to be delivered to the shutter assembly. The positive and negative voltage generators output the dark state drive signal to the shutter assembly to switch the shutter assembly from the light state to the dark state upon enablement by the weld detect circuit. The dark state drive signal includes a high voltage pulse followed by a stable AC waveform. The high voltage pulse is formed by a positive voltage signal and a negative voltage signal.
Abstract:
Radiation receiver with a photodetector and a sensor, wherein the sensor receives the radiation intensity, and a shutter arranged before the photodetector is driven in dependence on the detected incident radiation intensity. The incident radiation is supplied to the photodetector via a delay device arranged before the shutter, so that no radiation destroying the photodetector can reach the photodetector, due to the shutter having been driven, and can if necessary be kept away or absorbed by the shutter.
Abstract:
A photometering apparatus for measuring the brightness of an object to be photographed, includes a condenser lens having at least one aspheric lens surface for condensing a bundle of rays reflected from the object. A diaphragm is provided at a predetermined distance behind the condenser lens with respect to the object, and a split type light receiving device is provided behind the diaphragm to receive light which passes through the diaphragm. These elements satisfy the condition represented by the formula 0.3.ltoreq.L.sub.ASP /T.sub.L .ltoreq.0.7, wherein "T" represents the distance between the surface of the condenser lens nearer to the object to be photographed and the light receiving device, and wherein "L.sub.ASP " represents the reduced distance between the aspheric surface of the condenser lens and the diaphragm. The term "L.sub.ASP " is defined by the relationship L.sub.ASP =(d.sub.L /N)+d.sub.s, wherein "d.sub.L " represents the thickness of the lens, "d.sub.s " the distance between the diaphragm and the surface of the lens nearer to the image, and "N" the refractive index of the lens at the e-line.