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A vector monitor, vector display, or calligraphic display is a display device used for
computer graphics Computer graphics deals with generating images with the aid of computers. Today, computer graphics is a core technology in digital photography, film, video games, cell phone and computer displays, and many specialized applications. A great de ...
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
pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the ...
s 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. Some refresh vector displays use a normal phosphor 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 IMLAC Corporation was an American electronics company in Needham, Massachusetts, that manufactured graphical display systems, mainly, the PDS-1 and PDS-4, in the 1970s. The PDS-1 debuted in 1970. It was the first low-cost commercial realizatio ...
, require some local refresh memory to hold the vector endpoint data. Other
storage tube 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. A specialized type of storage tube, the Williams tube, was used as a main mem ...
displays, such as the popular
Tektronix 4010 The Tektronix 4010 series was a family of text-and-graphics computer terminals based on storage-tube technology created by Tektronix. Several members of the family were introduced during the 1970s, the best known being the 11-inch 4010 and 19-inc ...
, 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 is a mapping from some domain (for example, a range of integers) to bits. It is also called a bit array or bitmap index. As a noun, the term "bitmap" is very often used to refer to a particular bitmapping application: t ...
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 an effect that causes different signals to become indistinguishable (or ''aliases'' of one another) when sampled. It also often refers to the distortion or artifact that results when ...
and
pixelation In computer graphics, pixelation (or pixellation in British English) is caused by displaying a bitmap or a section of a bitmap at such a large size that individual pixels, small single-colored square display elements that comprise the bitmap, a ...
—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

In 1963, Ivan Sutherland at
MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
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 Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve co ...
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 simulated experience that employs pose tracking and 3D near-eye displays to give the user an immersive feel of a virtual world. Applications of virtual reality include entertainment (particularly video games), e ...
. In 1970, at the UK
Farnborough Airshow The Farnborough Airshow, officially 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. Since its fir ...
,
Sperry Gyroscope Sperry may refer to: Places In the United States: * Sperry, Iowa, community in Des Moines County * Sperry, Missouri * Sperry, Oklahoma, town in Tulsa County * Sperry Chalet, historic backcountry chalet, Glacier National Park, Montana *Sperry Glaci ...
( Bracknell, 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, monochrom ...
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 Etch A Sketch is a mechanical drawing toy invented by André Cassagnes of France and subsequently manufactured by the Ohio Art Company. It is now owned by Spin Master of Toronto, Ontario, Canada. An Etch A Sketch has a thick, flat gray screen in ...
, any deletion or movement requires erasing the entire screen with a bright green flash, and then slowly redrawing the entire image. Animation 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 (), 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 pilot being able to view informa ...
s in fighter aircraft 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 ''Armor Attack'' is multidirectional shooter designed by Tim Skelly and released in arcades by Cinematronics in 1980. It was licensed to Sega in Japan. The vector graphics of ''Armor Attack'' present combat between the player's jeep and enem ...
'', ''
Asteroids An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...
'', '' Omega Race'', ''
Tempest Tempest is a synonym for a storm. '' The Tempest'' is a play by William Shakespeare. Tempest or The Tempest may also refer to: Arts and entertainment Films * ''The Tempest'' (1908 film), a British silent film * ''The Tempest'' (1911 film), a ...
'', and '' Star Wars'', and in the
Vectrex The Vectrex is a vector display-based home video game console–the only one ever designed and released for the home market, developed by Smith Engineering. It was first released for the North America market in November 1982 and then Europe an ...
home videogame console. Hewlett-Packard made a series of large-screen X-Y (vector) displays, the first of which was the 20 MHz 8x10" 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" long CRT. Without the mesh, the 8x10" 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.


Color displays

Some vector monitors are capable of displaying multiple colors, using either a typical
shadow mask The shadow mask is one of the two technologies used in the manufacture of cathode-ray tube (CRT) televisions and computer monitors which produce clear, focused color images. The other approach is the aperture grille, better known by its tr ...
RGB CRT or two phosphor layers (so-called " penetration color"). Atari used the term ''color quadrascan'' to describe the shadow-mask version used in their video arcade games. 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. Some monochrome vector displays were able to display color using peripherals such as the
Vectrex The Vectrex is a vector display-based home video game console–the only one ever designed and released for the home market, developed by Smith Engineering. It was first released for the North America market in November 1982 and then Europe an ...
3-D Imager.


See also

*
Vector graphics Vector graphics is 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 display ...
*
Vectrex The Vectrex is a vector display-based home video game console–the only one ever designed and released for the home market, developed by Smith Engineering. It was first released for the North America market in November 1982 and then Europe an ...
*
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 ...


References


External links

* {{DEFAULTSORT:Vector Monitor Cathode ray tube