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Charactron was a U.S. registered trademark (number 0585950, 23 February 1954) of Consolidated Vultee Aircraft Corporation (Convair) for its shaped electron beam cathode ray tube. Charactron CRTs performed functions of both a display device and a read-only memory storing multiple characters and fonts. The similar Typotron was a U.S. registered trademark (23 November 1953) of Hughes Aircraft Corporation for its type of shaped electron beam storage tube with a direct-view bistable storage screen.
The United States Patent and Trademark Office (USPTO) is an agency in the U.S. Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.
Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953 it was purchased by General Dynamics, and operated as their Convair Division for most of its corporate history.
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, sometimes known as firmware. Software applications for programmable devices can be distributed as plug-in cartridges containing read-only memory.
The Charactron CRT used an electron beam to flood a specially patterned perforated anode that contained the stencil patterns for each of the characters that it could form. The first deflection positioning of the electron beam steered the beam to pass through one of the (typically 64 or 116) characters and symbols that could be formed. The beam, which then had the cross-section of the desired character, was re-centered along the axis of the tube and deflected to the desired position of the screen for display. Alternately, as in the accompanying image, the entire matrix was filled with the electron beam then deflected through a selection aperture to isolate one character.
The term Charactron is sometimes mistakenly applied to another type of CRT properly called a monoscope which generates an electrical signal by scanning an electron beam of uniform cross section across a printed pattern on an internal target electrode.
A monoscope was a special form of video camera tube which displayed a single still video image. The image was built into the tube, hence the name. The tube resembled a small cathode ray tube (CRT). Monoscopes were used beginning in the 1950s to generate TV test patterns and station logos. This type of test card generation system was technologically obsolete by the 1980s.
There were two basic types/uses of Charactrons:
The technical expertise, and trademarks, for the Charactron ultimately passed to Stromberg-Carlson, General Dynamics, Stromberg DatagraphiX, Anacomp, and finally Lexel Imaging Systems.
Stromberg-Carlson was a telecommunications equipment and electronics manufacturing company in the United States. It was formed in 1894 as a partnership by Alfred Stromberg and Androv Carlson. It was one of five companies that controlled the national supply of telephone equipment until after World War II.
General Dynamics Corporation (GD) is an American aerospace and defense corporation. As of 2019, it was the fifth-largest defense contractor in the United States, and the sixth-largest in the world, by sales. The company ranked No. 92 in the 2019 Fortune 500 list of the largest United States corporations by total revenue. It is headquartered in Reston, Fairfax County, Virginia.
Anacomp, Inc., is an American company that specializes in computer services and document management. It was founded in Indianapolis, Indiana, in 1968 by Ronald D. Palamara, Robert R. Sadaka, and J. Melvin Ebbert, three professors at Purdue University. Their goal was to direct the power of the computer toward the disciplines of investment management, education, urban analysis, computer science and civic systems, but is now headquartered in Chantilly, Virginia. The name Anacomp is a combination of the words ANAlyze and COMPute. Since its inception, Anacomp has made many acquisitions and spin-offs and has entered and exited different lines of business.
The cathode-ray tube (CRT) is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images. It modulates, accelerates, and deflects electron beam(s) onto the screen to create the images. The images may represent electrical waveforms (oscilloscope), pictures, radar targets, or other phenomena. CRTs have also been used as memory devices, in which case the visible light emitted from the fluorescent material is not intended to have significant meaning to a visual observer.
The Williams tube, or the Williams–Kilburn tube after inventors Freddie Williams and Tom Kilburn, is an early form of computer memory. It was the first random-access digital storage device, and was used successfully in several early computers.
The Selectron was an early form of digital computer memory developed by Jan A. Rajchman and his group at the Radio Corporation of America (RCA) under the direction of Vladimir K. Zworykin. It was a vacuum tube that stored digital data as electrostatic charges using technology similar to the Williams tube storage device. The team was never able to produce a commercially viable form of Selectron before magnetic-core memory became almost universal, and it remains practically unknown today.
A television set or television receiver, more commonly called a television, TV, TV set, or telly, is a device that combines a tuner, display, and loudspeakers for the purpose of viewing and hearing shows broadcast through satellites or cables or viewing and hearing a computer. Introduced in the late 1920s in mechanical form, television sets became a popular consumer product after World War II in electronic form, using cathode ray tubes. The addition of color to broadcast television after 1953 further increased the popularity of television sets in the 1960s, and an outdoor antenna became a common feature of suburban homes. The ubiquitous television set became the display device for the first recorded media in the 1970s, such as Betamax, VHS and later DVD. It has been used as a display device since the first generation of home computers and dedicated video game consoles in the 1980s. In the 2010s flat panel television incorporating liquid-crystal displays, especially LED-backlit LCDs, largely replaced cathode ray tubes and other displays. Modern flat panel TVs are typically capable of high-definition display and can also play content from a USB device.
Storage tubes are a class of cathode-ray tubes (CRTs) that are designed to hold an image for a long period of time, typically as long as power is supplied to the tube.
Direct-view bistable storage tube (DVBST) was an acronym used by Tektronix to describe their line of storage tubes. These were cathode ray tubes (CRT) that stored information written to them using an analog technique inherent in the CRT and based upon the secondary emission of electrons from the phosphor screen itself. The resulting image was visible in the continuously glowing patterns on the face of the CRT.
Cromaclear is a trademark for CRT technology used by NEC during the mid to late-90s. This adopted the slotted shadow mask and inline electron gun pioneered by the 1966 GE Porta-Color and used by most then-current television tubes to computer monitor use. It was claimed that Cromaclear could offer the image clarity and sharpness of the Trinitron and Diamondtron aperture grille CRTs without the disadvantages e.g. expense and the horizontal damping wires.
A vector monitor or vector display is a display device used for computer graphics up through the 1970s. It is a type of CRT, similar to that of an early oscilloscope. In a vector display, the image is composed of drawn lines rather than a grid of glowing pixels as in raster graphics. The electron beam follows an arbitrary path tracing the connected sloped lines, rather than following the same horizontal raster path for all images. The beam skips over dark areas of the image without visiting their points.
The Geer tube was an early single-tube color television cathode ray tube, developed by Willard Geer. The Geer tube used a pattern of small phosphor-covered three-sided pyramids on the inside of the CRT faceplate to mix separate red, green and blue signals from three electron guns. The Geer tube had a number of disadvantages, and was never used commercially due to the much better images generated by RCA's shadow mask system. Nevertheless, Geer's patent was awarded first, and RCA purchased an option on it in case their own developments didn't pan out.
The beam-index tube is a color television cathode ray tube (CRT) design, using phosphor stripes and active-feedback timing, rather than phosphor dots and a beam-shadowing mask as developed by RCA. Beam indexing offered much brighter pictures than shadow-mask CRTs, reducing power consumption, and as they used a single a electron gun rather than three, they were easier to build and keep in alignment.
Electrically operated display devices have developed from electromechanical systems for display of text, up to all-electronic devices capable of full-motion 3D color graphic displays. Electromagnetic devices, using a solenoid coil to control a visible flag or flap, were the earliest type, and were used for text displays such as stock market prices and arrival/departure display times. The cathode ray tube was the workhorse of text and video display technology for several decades until being displaced by plasma, liquid crystal (LCD) and solid-state devices such as LEDs and OLEDs. With the advent of microprocessors and microelectronic devices, many more individual picture elements ("pixels") could be incorporated into one display device, allowing graphic displays and video.
Nimo was the trademark of a family of very small non-standard CRTs manufactured by Industrial Electronics Engineers around mid-1960s, with 10 electron guns with stencils which shaped the electron beam as digits. The Nimo tube operated on a similar principle as the charactron, but used a much simpler design. They were intended as single digit, simple displays, or as 4 or 6 digits by means of a special horizontal magnetic deflection system. Having only 3 electrode types, the driving circuit for this tube was very simple, and as the image was projected on the glass face, it allowed a much wider viewing angle than for example nixie tubes which Nimo tried to replace.
Electron-stimulated luminescence (ESL) was a claimed method of producing light by cathodoluminescence, i.e. by a beam of electrons made to hit a fluorescent phosphor surface. This is also the method used to produce light in a cathode ray tube (CRT), but, unlike CRTs, ESL lamps do not include magnetic or electrostatic means to deflect the electron beam.
A scotophor is a material showing reversible darkening and bleaching when subjected to certain types of radiation. The name means dark bearer, in contrast to phosphor, which means light bearer. Scotophors show tenebrescence and darken when subjected to an intense radiation such as sunlight. Minerals showing such behavior include hackmanite sodalite, spodumene and tugtupite. Some pure alkali halides also show such behavior.
This is a subdivision of the Oscilloscope article, discussing the various types and models of oscilloscopes in greater detail.
Beam deflection tubes, sometimes known as sheet beam tubes, are vacuum tubes with an electron gun, a beam intensity control grid, a screen grid, sometimes a suppressor grid, and two electrostatic deflection electrodes on opposite sides of the electron beam, that can direct the rectangular beam to either of two anodes in the same plane. They can be used as two-quadrant, single-balanced mixers or (de)modulators with very linear qualities, their mode of operation similar to one-half of a Gilbert Cell, by applying an unbalanced signal f1 to the control grid and a balanced signal f2 to the deflection electrodes, then extracting the balanced mixing products f1 − f2 and f1 + f2 from the two anodes. Similar to a pentagrid converter, the cathode and the first two grids can be made into an oscillator. Two beam deflection tubes can be combined to form a double-balanced mixer.
A deflection yoke is a kind of magnetic lens, used in cathode ray tubes to scan the electron beam both vertically and horizontally over the whole screen.
The Photographic Display Unit, or PDU, was a large-format display system used by the Royal Air Force to present radar images for interpretation by a number of operators and commanders. Made by Kelvin Hughes, it projected a 6 feet (1.8 m) diameter image that could optionally be overlaid with a map and range rings. The PDU was originally designed for the ROTOR system and subsequent AMES Type 80-based Master Radar Stations. A smaller version with a 24 inches (610 mm) display was used onboard Royal Navy ships, and a larger version projected onto movie screens was used in the SAGE system in the US.
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