A sectional view of an image orthicon is shown in the below figure. It has three main sections: image section, scanning section and electron. Historical information about the start of the first television camera tubes. The huge 4,5″ EEV Image Orthicon with in front a 2/3″ Vidicon tube. This EEV. This chapter discusses television X-ray image intensifiers that use an image orthicon camera tube of the type used in many television studios. The electrostatic.
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Despite these advantages, acceptance and incorporation of solid-state sensors into television and video cameras was not immediate. The phenomenon known as magnetic focusing was discovered by A.
September 5,p. It uses a vertically striped RGB color filter over the faceplate of an otherwise standard vidicon imaging tube to segment the scan into corresponding red, green and blue segments. While still a part of Philips, the company purchased EEV’s English Electric Valve lead oxide camera tube business, and gained a monopoly in lead-oxide tube production.
It has three main sections: The first practical iconoscope was constructed in by Sanford Essig, when he accidentally left a silvered mica sheet in the oven too long. The fluctuating voltage coupled out to a video amplifier can be used to reproduce the scene being imaged. In Junethe scientific journal Nature published a letter in which Alan Archibald Campbell-Swintonfellow of the Royal Society UKdiscussed how a fully electronic television system could be realized by using cathode ray tubes or “Braun” tubes, after its inventor, Karl Braun as both imaging and display devices.
Convention date UK application: The electron image is periodically deflected horizontally and vertically ” raster scanning ” such that the entire image is read by the detector many times per second, producing an electrical signal that can be conveyed to a display devicesuch as a CRT monitor, to reproduce the image. The scene image is then projected onto the back side of the plate, while the low-velocity electron beam scans the photoelectric mosaic at the front side.
The target is nearly at ground potential with a small positive charge, thus when the electrons reach the target at low speed inage are absorbed without ejecting more electrons. Its first image was transmitted in late summer of and a patent was issued orthcon A more common technique and a simpler one from the tube construction standpoint was to overlay the photosensitive target with a color orthicoon filter having orthhicon fine pattern of vertical stripes of green, cyan and clear filters i.
That is, giving the illusion of being more sharply focused than it actually is.
The Institute of Electrical Engineers. Any vacuum tube which operates using a focused beam of electrons, ” cathode rays “, is known as a cathode ray tube CRT. Davis, the general manager of Westinghouseand Zworykin was asked “to work on something useful”. This configurations allows the use of a straight camera tube, because the scene to be transmitted, the charge storage plate, and the electron gun can be aligned one after the other.
United Imaye Intellectual Property Office. Its surface consists of selenium with trace amounts of arsenic and tellurium added SeAsTe to make the signal more stable.
Each individual electron from the electron image produces several secondary electrons after reaching tubf target, so that an orthifon effect is produced. Three million tiny photo cells ‘memorize’, then pass out pictures. During the s and s, field-sequential color systems were developed which used synchronized motor-driven color-filter disks at the camera’s image tube and at the television receiver.
The orthicon and image orthicon were both great improvements umage design over the pre-WWII designs such as the Image Dissector and Iconoscope and orthicno derivatives. The technique would not work with the baseline vidicon tube because it suffered from the limitation that as the target was fundamentally an insulator, the constant low light level built up a charge which would manifest itself as a form of ‘fogging’.
Video camera tube – Wikipedia
Finally, an electron beam periodically sweeps across the target, effectively scanning the stored image, discharging each granule, and producing an electronic signal like in the iconoscope. Proceedings of odthicon IRE, volume 27, issue 9. The output from the detector is an electric current whose magnitude is a measure of the brightness of the corresponding area of the image. This adjustment helps to improve the landing characteristics of the beam.
The target is constructed of a mosaic of electrically isolated metallic granules separated from a common plate by a thin layer of isolating material, so that the positive charge resulting from the secondary emission is stored in the capacitor formed by the metallic granule and the common plate.
This effect was actually “cultivated” by tube manufacturers to a certain extent, as a small, carefully controlled amount of the dark halo has the effect of “crispening” the visual image due to the contrast effect. The life and times of A D Blumlein.
Fast as a movie camera.
A low noise signal is available as the tube’s output. Dictionary of Video and Television Technology. One technique has already been described Trinicon above.
Thanks to the axial magnetic field of the focusing coilthis deflection is not in a straight line, thus when the electrons reach the orthucon they do so perpendicularly avoiding a sideways component. The electron gun structure produces a beam of electrons that is accelerated towards the target. The method of extracting the color is similar however. Previous color stripe systems had used colors where the color circuitry was able to separate the colors purely from the relative amplitudes of the signals.
Please help improve this section by adding citations to reliable sources. A sharply focused beam of electrons a cathode ray is generated by the electron gun at ground potential and accelerated by the anode the first dynode of the electron multiplier around the gun at a high positive voltage approx. The target is constructed of a mosaic of electrically isolated metallic granules separated from a common plate by a thin layer of isolating material, so that the positive charge resulting tubr the secondary emission is stored in the granules.
Once the image electrons reach the target, they cause a “splash” of electrons by the effect of secondary emission. The photo-electrons are omage on to the target by the combined action of the electrostatic field and a longitudinal magnetic field, the imge being produced by an external coil.