This invention provides a display element comprising a support, a phosphorescent material, and at least one layer containing a silver halide emulsion, wherein the phosphorescent material is not excited upon exposure of the silver halide emulsion. It further provides methods of exposing and processing such display elements.

A monitoring system useful for monitoring the state of a fiber communication channel in which a portion of the fiber signal is tapped and detected by a photodiode. The dark current of the photodiode and other DC offsets of the system may be compensated by passing a known signal through the photodiode and extracting the component due to the known signal. The known signal may be a locally generated optical signal having a predetermined harmonic signature. Optionally, the fiber signal may be select...

Dark current compensation in a video imaging tube is accomplished by virtue of establishing a dark current level and subtracting it from the video signal. The dark current level can be established by overscanning or scanning a nonexposed area of the image tube or by means of a compensating video sensing segment positioned directly on the actual video sensing segment. In a silicon target tube, the compensating junction can consist of a conveniently sized assembly or mosaiced junctions similar to ...

A metallic product having a dark, nonreflective and nonflaking surface is disclosed. A method of manufacturing the dark, nonreflective and nonflaking surface is also disclosed.

A device is provided for writing in the dark which has the external appearance of a book. Inside the book, a box is attached to the inside of one of the covers. The box contains a continuous strip paper supply which is drawn from underneath an illuminated translucent panel through channels that lead the paper over the translucent panel and under a lid which guides the paper across the pane so that the paper may be drawn out from the box. The lid has an opening through which the user may write on...

A dark current compensation circuit for a television camera features a switch for controlling an X-ray tube located in front of the camera, a video amplifier is coupled to the camera and a peak rectifier circuit is in turn coupled to the amplifier output. A switch synchronized with the first switch connects the rectifier to a capacitor to establish a dark current bias voltage which is applied to the amplifier.

The disclosure relates to an electrical circuit and method for suppressing the effect of undesirable electrical signal, such as, the dark current of a photomultiplier tube. The circuit comprises, preferably, a current-to-volts amplifier with a feedback that includes a noninverting amplifier and a memory. The method for suppressing the effect of dark current consists of biasing the memory under no light conditions until the output potential of the current-to-volts amplifier is zeroed to the input...

The illuminated animal collar includes a plurality of illuminating means along the surface of the collar. A switch is included, along with rechargeable power means. A plurality of solar cells are included to periodically recharge the rechargeable power means.

A smoke detector includes a dark chamber surrounded by a peripheral wall structure having a plurality of nested vanes. The second element of each vane is shorter than the first, and intersects the first element intermediate its ends at an acute angle. Adjacent vanes define a tortuous path that requires a minimum of three, and in most cases four, reflections for light to reach the inside of the chamber. Adjacent vanes define twisted channels leading from outside the chamber into the chamber for b...

The present invention relates to platelet-like pigments of dark surface color and to their preparation process and use.