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A vector monitor, vector display, or calligraphic display is a
display device A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signa ...
used for
computer graphics Computer graphics deals with generating images and art with the aid of computers. Computer graphics is a core technology in digital photography, film, video games, digital art, cell phone and computer displays, and many specialized applications. ...
up through the 1970s. It is a type of
CRT CRT or Crt most commonly refers to: * Cathode-ray tube, a display * Critical race theory, an academic framework of analysis CRT may also refer to: Law * Charitable remainder trust, United States * Civil Resolution Tribunal, Canada * Columbia ...
, similar to that of an early
oscilloscope An oscilloscope (formerly known as an oscillograph, informally scope or O-scope) is a type of electronic test instrument that graphically displays varying voltages of one or more signals as a function of time. Their main purpose is capturing i ...
. In a vector display, the image is composed of drawn lines rather than a grid of glowing
pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...
s as in
raster graphics upright=1, The Smiley, smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for ...
. The
electron beam Since the mid-20th century, electron-beam technology has provided the basis for a variety of novel and specialized applications in semiconductor manufacturing, microelectromechanical systems, nanoelectromechanical systems, and microscopy. Mechani ...
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. Some refresh vector displays use a normal
phosphor A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or ...
that fades rapidly and needs constant refreshing 30-40 times per second to show a stable image. These displays, such as the Imlac PDS-1, require some local refresh memory to hold the vector endpoint data. Other storage tube displays, such as the popular Tektronix 4010, use a special phosphor that continues glowing for many minutes. Storage displays do not require any local memory. In the 1970s, both types of vector displays were much more affordable than
bitmap In computing, a bitmap (also called raster) graphic is an image formed from rows of different colored pixels. A GIF is an example of a graphics image file that uses a bitmap. As a noun, the term "bitmap" is very often used to refer to a partic ...
raster graphics displays when megapixel computer memory was still very expensive. Today, raster displays have replaced nearly all uses of vector displays. Vector displays do not suffer from the display artifacts of
aliasing In signal processing and related disciplines, aliasing is a phenomenon that a reconstructed signal from samples of the original signal contains low frequency components that are not present in the original one. This is caused when, in the ori ...
and pixelation—especially black and white displays; color displays keep some artifacts due to their discrete nature—but they are limited to displaying only a shape's outline (although advanced vector systems can provide a limited amount of shading). Text is crudely drawn from short strokes. Refresh vector displays are limited in how many lines or how much text can be shown without refresh flicker. Irregular beam motion is slower than steady beam motion of raster displays. Beam deflections are typically driven by magnetic coils, and those coils resist rapid changes to their current.


History

The vector display was first invented by
Jonathan Zenneck Jonathan Adolf Wilhelm Zenneck (; ; 15 April 1871 – 8 April 1959) was a German physicist and electrical engineer. Zenneck improved the cathode-ray tube by adding a second deflection structure at right angles to the first, which allowed two-di ...
via use of a Braun cathode-ray tube. His solution was able to produce fundamental waveforms using two deflection cowls a high-powered cathode inside of the tube to create a continuously swept image. This device was utilized by early radio engineers, but was not practical until
John Bertrand Johnson John Erik Bertrand Johnson (born Johan Erik Bertrand; October 2, 1887 – November 27, 1970) was a Swedish-born American electrical engineer and physicist. He created the first cathode-ray tube oscilloscope and detailed a fundamental source of r ...
implemented the
hot cathode In vacuum tubes and gas-filled tubes, a hot cathode or thermionic cathode is a cathode electrode which is heated to make it emit electrons due to thermionic emission. This is in contrast to a cold cathode, which does not have a heating element ...
to drastically reduce the voltage requirements for the device. The Cathode Ray Oscillograph was subsequently commercialized and became the basis for the modern oscilloscope. Oscilloscopes were used by electrical engineers to map out physical forces, as well as by recording engineers to understand the nature of human voices. The displays also became a frequent add-on to advanced electronic
analog computers An analog computer or analogue computer is a type of computation machine (computer) that uses physical phenomena such as Electrical network, electrical, Mechanics, mechanical, or Hydraulics, hydraulic quantities behaving according to the math ...
to visualize complex forces. The first
RADAR Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
systems utilized vector graphic oscilloscopes to map aircraft positions. Vector graphics in computers first emerged with the
Whirlwind A whirlwind is a phenomenon in which a vortex of wind (a vertically oriented rotating column of air) forms due to instabilities and turbulence created by heating and flow ( current) gradients. Whirlwinds can vary in size and last from a cou ...
system built by the
Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
's
Lincoln Laboratory The MIT Lincoln Laboratory, located in Lexington, Massachusetts, is a United States Department of Defense federally funded research and development center chartered to apply advanced technology to problems of national security. Research and dev ...
. Utilizing oscilloscope tubes, the Whirlwind displays could produce complex readings of airborne trajectory, as well as played host to the first graphical demo, ''Bouncing Ball'' (1951). In 1956, the first
light pen A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with a computer's cathode-ray tube (CRT) display. It allows the user to point to displayed objects or draw on the screen in a similar way to a to ...
was implemented on the Whirlwind system. These technologies then became the basis for the advanced US SAGE air defense system which was fully active in 1958. In 1963,
Ivan Sutherland Ivan Edward Sutherland (born May 16, 1938) is an American computer scientist and Internet pioneer, widely regarded as a pioneer of computer graphics. His early work in computer graphics as well as his teaching with David C. Evans in that subje ...
at
MIT The Massachusetts Institute of Technology (MIT) is a private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of modern technology and sc ...
first used a vector graphic display for
Sketchpad Sketchpad (a.k.a. Robot Draftsman) is a computer program written by Ivan Sutherland in 1963 in the course of his PhD thesis, for which he received the Turing Award in 1988, and the Kyoto Prize in 2012. It pioneered human–computer interaction ...
, his pioneering CAD program. In 1968, he and his team again used a vector monitor to display wireframe images of 3D models. This time the display was head mounted. The obviously heavy system was held up by a support arm structure called The Sword of Damocles. The system is widely considered to be the first computer-based
virtual reality Virtual reality (VR) is a Simulation, simulated experience that employs 3D near-eye displays and pose tracking to give the user an immersive feel of a virtual world. Applications of virtual reality include entertainment (particularly video gam ...
. Ivan Sutherland later co-founded the company
Evans & Sutherland Evans & Sutherland is an American computer graphics firm founded in 1968 by David C. Evans (computer scientist), David Evans and Ivan Sutherland. Its current products are used in digital projection environments like planetariums. Its simulation b ...
, which made high-end vector displays and flight simulators. In 1970, at the UK
Farnborough Airshow The Farnborough International Airshow is a trade exhibition for the aerospace and defence industries, where civilian and military aircraft are demonstrated to potential customers and investors in Farnborough, Hampshire. Since its first show in ...
, Sperry Gyroscope (
Bracknell Bracknell () is a town and civil parish in Berkshire, England, the westernmost area within the Greater London Built-up Area, Greater London Urban Area and the administrative centre of the borough of Bracknell Forest. It lies to the east of Re ...
, England) exhibited the first ever vector graphic video display from a UK company. It featured an analogue
monochrome A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, mon ...
display with special electronics, designed by Sperry's John Atkins, that allowed it to draw vectors on screen between two pairs of coordinates. At Farnborough the display was used to demonstrate the capabilities of the new Sperry 1412 military computer - it was shown running software that drew, in real time, a wire-frame rotating cube that could be speed-controlled in any of its three dimensions. That demonstration created significant interest in the Sperry 1412 computer, which then went on to be at the heart of a number of major projects for the French Navy and the Royal Navy during the period 1972 to 1992.


Examples

Notable among vector displays are Tektronix large-screen computer terminals that use direct-view storage CRTs. (The CRT has at least one flood gun, and a special type of display screen, more complicated in principle than a simple phosphor.) But that permanent image cannot be easily changed. Like an Etch-a-Sketch, any deletion or movement requires erasing the entire screen with a bright green flash, and then slowly redrawing the entire image.
Animation Animation is a filmmaking technique whereby still images are manipulated to create moving images. In traditional animation, images are drawn or painted by hand on transparent celluloid sheets to be photographed and exhibited on film. Animati ...
with this type of monitor is not practical. Vector displays were used for
head-up display A head-up display, or heads-up display, also known as a HUD () or head-up guidance system (HGS), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a ...
s in
fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...
because of the brighter displays that can be achieved by moving the electron beam more slowly across the phosphors. Brightness was critical because the display needed to be clearly visible to the pilot in direct sunlight. Vector monitors were also used by some late-1970s to mid-1980s arcade games such as '' Armor Attack'', ''
Asteroids An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
'', '' Omega Race'', '' Tempest'', and ''
Star Wars ''Star Wars'' is an American epic film, epic space opera media franchise created by George Lucas, which began with the Star Wars (film), eponymous 1977 film and Cultural impact of Star Wars, quickly became a worldwide popular culture, pop cu ...
'', and in the Vectrex home videogame console.
Hewlett-Packard The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company. It was founded by Bill Hewlett and David Packard in 1939 in a one-car garage in Palo Alto, California ...
made a series of large-screen X-Y (vector) displays, the first of which was the 20 MHz 8x10-inch model 1300. The CRT had an internal, specially contoured, very fine mesh operating at low potential, which was placed after the deflection plates at the gun exit. The 17KV electrostatic field between this mesh and the separate, conductive coating charged to final accelerating potential inside the CRT funnel, accelerated the electron beam axially as well as radially, expanding the possible image size to cover the 8x10" screen of the 17.75-inch long CRT. Without the mesh, the 8x10-inch CRT would have had to be almost three times as long. Expansion mesh technology was developed in the early 1960s by the need to drive deflection plates at high frequencies in compact high-brightness CRTs operating at high acceleration voltages, to take advantage of the then-new transistor technology which was limited to only low voltages. The much bulkier and less efficient vacuum-tube electrostatic deflection amplifiers were able to operate at hundreds of volts. The
Digistar Digistar is the first computer graphics-based planetarium projection and content system. It was designed by Evans & Sutherland and released in 1983. The technology originally focused on accurate and high quality display of stars, including for the ...
planetarium A planetarium (: planetariums or planetaria) is a theatre built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation. A dominant feature of most planetariums is ...
projection system, made by
Evans & Sutherland Evans & Sutherland is an American computer graphics firm founded in 1968 by David C. Evans (computer scientist), David Evans and Ivan Sutherland. Its current products are used in digital projection environments like planetariums. Its simulation b ...
, was originally a vector display that could render both stars and wire-frame graphics. Later versions use high resolution raster projection, but the vector-based Digistar and Digistar II were installed in many planetariums, and a few may still be in operation. A Digistar prototype was used for rendering 3D star fields for the film Star Trek II: The Wrath of Khan. Another E&S vector display, the Picture System II, was possibly also used for the film.


Color displays

Some vector monitors are capable of displaying multiple colors, using either a typical
shadow mask A shadow is a dark area on a surface where light from a light source is blocked by an object. In contrast, shade occupies the three-dimensional volume behind an object with light in front of it. The cross-section of a shadow is a two-dimensional ...
RGB CRT or two phosphor layers (so-called " penetration color"). In the penetration tubes, by controlling the strength of the electron beam, electrons can be made to reach (and illuminate) either or both phosphor layers, typically producing a choice of green, orange, or red. Tektronix made color oscilloscopes for a few years using penetration CRTs, but demand for these was low. Atari used the term ''color quadrascan'' to describe the shadow-mask version used in their video arcade games. Some monochrome vector displays were able to display color using peripherals such as the Vectrex 3-D Imager.


See also

*
Vector graphics Vector graphics are a form of computer graphics in which visual images are created directly from geometric shapes defined on a Cartesian plane, such as points, lines, curves and polygons. The associated mechanisms may include vector displ ...
* Vectrex *
Raster scan A raster scan, or raster scanning, is the rectangular pattern of image capture and reconstruction in television. By analogy, the term is used for raster graphics, the pattern of image storage and transmission used in most computer bitmap image s ...


References


External links

* {{DEFAULTSORT:Vector Monitor Cathode ray tube