When hit by the electron beam from the back of the CRT, this normally white material turns a magenta color, producing a dark spot or line on the display. The pattern remains on the display until erased by heating the potassium chloride layer.
Skiatrons were used as an early form of projection television display, particularly in radar stations during World War II. These tubes are also sometimes known as dark trace CRTs or dark trace tubes.[1]
During World War II, radar displays using potassium chloride evaporated on a mica plate as target material were actively developed in England, Germany, the United States, and the Soviet Union.[2][3][4][5][6] Being naturally cathodochromic,[7] potassium chloride did not require any special processing or treatment to become a CRT target material.
When hit by the electron beam from the back of the CRT, this normally white material turns a magenta color, producing a dark spot or line on the display, which resulted in the term "dark trace" being applied to these devices. The pattern remains on the display until erased by heating the potassium chloride layer. This physical property is known as tenebrescence or reversible photochromism.[8]
Skiatrons were used as an early form of projection television display, particularly in radar stations during World War II. The skiatron was mounted below a translucent plotting table surface and brightly lit with mercury arcstage lights. The image on the surface reflected onto the bottom of the plotting table, using a spherical mirror and a Schmidt corrector plate, in the same fashion as an opaque projector, producing an image of the radar display at a much larger size.[9][a] In RAF stations, the surface had a map on it, in Royal Navy ships it was normally a series of radial lines. Operators viewing the surface would place markers on the projected traces, adding new markers as the traces moved. This produced trails of markers making the path of the targets clear.[10]
A variety of methods were used to erase the skiatrons. UK radars used fans to cool the tubes which were being heated by the stage lighting of the projectors. Simply turning off the fans made the tube begin to warm up, the erasure taking perhaps 10 to 20 seconds. German examples used a thin, transparent layer of tungsten deposited on the front of the tube, which heated up when current was passed through it. This provided much faster erasing.[11]
Post-war developmentsedit
After the war, skiatrons were also used for storage oscilloscopes, which were viewed directly instead of as a projection system.[1] Some examples included separate areas on the screen covered with potassium chloride or phosphor, allowing the display to be set up on the phosphor section and then recorded on the skiatron section. There was some interest in the post-war era using skiatrons for large-format projection televisions,[12] but no known commercial use can be found.[citation needed]
Even the use in radar was not widespread; looking for an even larger format system with better properties, the RAF turned to the Photographic Display Unit, a system that took a photograph of the display, rapidly processed it, and then projected it through a modified movie projector. Even with this complexity, it was faster than the skiatrons, producing a new image every 15 seconds[13] while the skiatron units were typically longer due to the erasure process.[citation needed]
Notesedit
^During WWII, CRTs were typically between 3 and 6 inches, these displays were on the order of several feet across.
^Adams, D.C. (2006). "The Kelvin-Hughes Photographic Display Unit (PDU)". Ventnor Radar. Retrieved 21 May 2017.
Bibliographyedit
"The Skiatron". Radar Recollections.
King, P. (January 1946). "The Skiatron or Dark Trace Tube". Journal of the Institution of Electrical Engineers - Part IIIA: Radiolocation. 93 (1): 171–172. doi:10.1049/ji-3a-1.1946.0045.
King, P.; Gittins, J. (May 1946). "The Skiatron or Dark Trace Tube". Journal of the Institution of Electrical Engineers - Part IIIA: Radiolocation. 93 (5): 822–831. doi:10.1049/ji-3a-1.1946.0175.
Kingsley, F.A. (27 July 2016). The Development of Radar Equipments for the Royal Navy, 1935–45. Springer. ISBN978-1-349-13457-1.
Leverenz, H. W. (1946). "Luminescence and tenebrescence as applied in radar" (PDF). RCA Review. 7: 199–239.
Rosenthal, A.H. (1940). "The Skiatron - a new Scophony development towards large screen television projection" (PDF). Electronics and Television & Short- Wave World: 74–81.
Wikkenhauser, G. (January 1948). "The Skiatron or Dark Trace Tube and its Applications" (PDF). Electronic Engineering: 20–22.
Waltz, George Jr. (July 1948). "Theater Vision". Popular Science. pp. 109–113.
"4AP10 Skiatron data sheet" (PDF). RCA. 3 November 1944.
skiatron, skiatron, type, cathode, tube, that, replaces, conventional, phosphor, with, some, type, scotophor, typically, potassium, chloride, when, electron, beam, from, back, this, normally, white, material, turns, magenta, color, producing, dark, spot, line,. The skiatron is a type of cathode ray tube CRT that replaces the conventional phosphor with some type of scotophor typically potassium chloride When hit by the electron beam from the back of the CRT this normally white material turns a magenta color producing a dark spot or line on the display The pattern remains on the display until erased by heating the potassium chloride layer Skiatrons were used as an early form of projection television display particularly in radar stations during World War II These tubes are also sometimes known as dark trace CRTs or dark trace tubes 1 Contents 1 Description 2 Post war developments 3 Notes 4 References 4 1 Citations 4 2 BibliographyDescription editDuring World War II radar displays using potassium chloride evaporated on a mica plate as target material were actively developed in England Germany the United States and the Soviet Union 2 3 4 5 6 Being naturally cathodochromic 7 potassium chloride did not require any special processing or treatment to become a CRT target material When hit by the electron beam from the back of the CRT this normally white material turns a magenta color producing a dark spot or line on the display which resulted in the term dark trace being applied to these devices The pattern remains on the display until erased by heating the potassium chloride layer This physical property is known as tenebrescence or reversible photochromism 8 Skiatrons were used as an early form of projection television display particularly in radar stations during World War II The skiatron was mounted below a translucent plotting table surface and brightly lit with mercury arc stage lights The image on the surface reflected onto the bottom of the plotting table using a spherical mirror and a Schmidt corrector plate in the same fashion as an opaque projector producing an image of the radar display at a much larger size 9 a In RAF stations the surface had a map on it in Royal Navy ships it was normally a series of radial lines Operators viewing the surface would place markers on the projected traces adding new markers as the traces moved This produced trails of markers making the path of the targets clear 10 A variety of methods were used to erase the skiatrons UK radars used fans to cool the tubes which were being heated by the stage lighting of the projectors Simply turning off the fans made the tube begin to warm up the erasure taking perhaps 10 to 20 seconds German examples used a thin transparent layer of tungsten deposited on the front of the tube which heated up when current was passed through it This provided much faster erasing 11 Post war developments editAfter the war skiatrons were also used for storage oscilloscopes which were viewed directly instead of as a projection system 1 Some examples included separate areas on the screen covered with potassium chloride or phosphor allowing the display to be set up on the phosphor section and then recorded on the skiatron section There was some interest in the post war era using skiatrons for large format projection televisions 12 but no known commercial use can be found citation needed Even the use in radar was not widespread looking for an even larger format system with better properties the RAF turned to the Photographic Display Unit a system that took a photograph of the display rapidly processed it and then projected it through a modified movie projector Even with this complexity it was faster than the skiatrons producing a new image every 15 seconds 13 while the skiatron units were typically longer due to the erasure process citation needed Notes edit During WWII CRTs were typically between 3 and 6 inches these displays were on the order of several feet across References editCitations edit a b Wikkenhauser 1948 p 20 UK 513776 Rosenthal Adolph H Improvements in or relating to television receivers issued 1938 02 03 Kingsley 2016 p 125 Rosenthal 1940 King 1946 King amp Gittins 1946 nbsp The dictionary definition of cathodochromism at Wiktionary Leverenz 1946 King 1946 p 171 Wikkenhauser 1948 p 21 Wikkenhauser 1948 p 22 Waltz 1948 p 113 Adams D C 2006 The Kelvin Hughes Photographic Display Unit PDU Ventnor Radar Retrieved 21 May 2017 Bibliography edit The Skiatron Radar Recollections King P January 1946 The Skiatron or Dark Trace Tube Journal of the Institution of Electrical Engineers Part IIIA Radiolocation 93 1 171 172 doi 10 1049 ji 3a 1 1946 0045 King P Gittins J May 1946 The Skiatron or Dark Trace Tube Journal of the Institution of Electrical Engineers Part IIIA Radiolocation 93 5 822 831 doi 10 1049 ji 3a 1 1946 0175 Kingsley F A 27 July 2016 The Development of Radar Equipments for the Royal Navy 1935 45 Springer ISBN 978 1 349 13457 1 Leverenz H W 1946 Luminescence and tenebrescence as applied in radar PDF RCA Review 7 199 239 Rosenthal A H 1940 The Skiatron a new Scophony development towards large screen television projection PDF Electronics and Television amp Short Wave World 74 81 Wikkenhauser G January 1948 The Skiatron or Dark Trace Tube and its Applications PDF Electronic Engineering 20 22 Waltz George Jr July 1948 Theater Vision Popular Science pp 109 113 4AP10 Skiatron data sheet PDF RCA 3 November 1944 16LM4G Skiatron data sheet PDF in Russian Moscow Electric Lamp Plant MELZ MELZ Retrieved from https en wikipedia org w index php title Skiatron amp oldid 1161295776, wikipedia, wiki, book, books, library,
