Information about Shadow Mask
This article is about cathode ray tube (CRT) televisions and computer displays. For shadow masking in 3D computer graphics, see shadow mapping.
)
Shadow mask based CRT in close-up.
The shadow mask is one of two major technologies used to manufacture cathode ray tube (CRT) televisions and computer displays that produce color images (the other is aperture grille). Tiny holes in a metal plate separate the colored phosphors in the layer behind the front glass of the screen. The holes are placed in a manner ensuring that electrons from each of the tube's three cathode guns reach only the appropriately-colored phosphors on the display. All three beams pass through the same holes in the mask, but the angle of approach is different for each gun. The spacing of the holes, the spacing of the phosphors, and the placement of the guns is arranged so that for example the blue gun only has an unobstructed path to blue phosphors. The red, green, and blue phosphors for each pixel are generally arranged in a triangular shape (sometimes called a "triad"). All early color televisions and the majority of CRT computer monitors, past and present, use shadow mask technology. This principle was first proposed by Werner Flechsig in a German patent in 1938.
Traditionally, shadow masks have been made of materials which temperature variations cause to expand and contract to the point of affecting performance. The energy the shadow mask absorbs from the electron gun in normal operation causes it to heat up and expand, which leads to blurred or discolored (see doming) images. The invar shadow mask, which is composed of the nickel-iron alloy invar, expands and contracts much less than other materials in response to temperature changes. This property allows displays made with this technology to provide a clearer, more accurate picture. It also reduces the amount of long-term stress and damage to the shadow mask that can result from repeated expand/contract cycles, thus increasing the display's life expectancy.
While many long have considered aperture grille technology to produce superior images, advances in shadow mask and hybrid technologies since the 1990s have made purchasing decisions more a matter of personal choice or specific application. The arrival of inexpensive liquid crystal display (LCD) monitors and other flat-screen designs now challenges both aperture grille and shadow mask CRT's long reign as the technology behind the screens at which we look.
See also
External links
1. Electron guns 2. Electron beams 3. Focusing coils 4. Deflection coils 5. Anode connection 6. Mask for separating beams for red, green, and blue part of displayed image 7.
..... Click the link for more information.
..... Click the link for more information.
Television (often abbreviated to TV, T.V., or more recently, tv; sometimes called telly, the tube, boob tube, or idiot box in British English) is a widely used telecommunication system for broadcasting and receiving moving pictures
..... Click the link for more information.
..... Click the link for more information.
A computer display monitor, usually called simply a monitor, is a piece of electrical equipment which displays viewable images generated by a computer without producing a permanent record.
..... Click the link for more information.
..... Click the link for more information.
3D computer graphics (in contrast to 2D computer graphics) are graphics that utilize a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering 2D images.
..... Click the link for more information.
..... Click the link for more information.
Shadow mapping or projective shadowing is a process by which shadows are added to 3D computer graphics. This concept was introduced by Lance Williams in 1978, in a paper entitled "Casting curved shadows on curved surfaces".
..... Click the link for more information.
..... Click the link for more information.
1. Electron guns 2. Electron beams 3. Focusing coils 4. Deflection coils 5. Anode connection 6. Mask for separating beams for red, green, and blue part of displayed image 7.
..... Click the link for more information.
..... Click the link for more information.
Television (often abbreviated to TV, T.V., or more recently, tv; sometimes called telly, the tube, boob tube, or idiot box in British English) is a widely used telecommunication system for broadcasting and receiving moving pictures
..... Click the link for more information.
..... Click the link for more information.
A computer display monitor, usually called simply a monitor, is a piece of electrical equipment which displays viewable images generated by a computer without producing a permanent record.
..... Click the link for more information.
..... Click the link for more information.
Color or colour[1] (see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, yellow, blue, black, etc.
..... Click the link for more information.
..... Click the link for more information.
aperture grille (tension mask) is one of two major technologies used to manufacture color cathode ray tube (CRT) televisions and computer displays; the other is shadow mask.
..... Click the link for more information.
..... Click the link for more information.
A phosphor is a substance that exhibits the phenomenon of phosphorescence (sustained glowing after exposure to light or energised particles such as electrons).
The chemical element phosphorus (Greek.
..... Click the link for more information.
The chemical element phosphorus (Greek.
..... Click the link for more information.
Electron
Theoretical estimates of the electron density for the first few hydrogen atom electron orbitals shown as cross-sections with color-coded probability density
Composition: Elementary particle
Family: Fermion
Group: Lepton
Generation: First
..... Click the link for more information.
Theoretical estimates of the electron density for the first few hydrogen atom electron orbitals shown as cross-sections with color-coded probability density
Composition: Elementary particle
Family: Fermion
Group: Lepton
Generation: First
..... Click the link for more information.
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 625–750 nm.
..... Click the link for more information.
..... Click the link for more information.
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nm. It is considered one of the additive primary colors.
..... Click the link for more information.
..... Click the link for more information.
The term blue may refer to any of a number of similar colours. The sensation of blue is made by light having a spectrum dominated by energy in the wavelength range of about 440–490 nm.
..... Click the link for more information.
..... Click the link for more information.
pixel (short for picture element, using the common abbreviation "pix" for "pictures") is a single point in a graphic image. Each such information element is not really a dot, nor a square, but an abstract sample.
..... Click the link for more information.
..... Click the link for more information.
A triangle is one of the basic shapes of geometry: a polygon with three corners or and three sides or edges which are straight line segments.
In Euclidean geometry any three non-collinear points determine a triangle and a unique plane, i.e.
..... Click the link for more information.
In Euclidean geometry any three non-collinear points determine a triangle and a unique plane, i.e.
..... Click the link for more information.
triad is a group of three phosphor dots coloured red, green, and blue on the inside of the CRT display of a computer monitor or television set. By directing differing intensities of electron beams onto the three phosphor dots, the triad will display a colour by combining the red,
..... Click the link for more information.
..... Click the link for more information.
19th century - 20th century - 21st century
1900s 1910s 1920s - 1930s - 1940s 1950s 1960s
1935 1936 1937 - 1938 - 1939 1940 1941
Year 1938 (MCMXXXVIII
..... Click the link for more information.
1900s 1910s 1920s - 1930s - 1940s 1950s 1960s
1935 1936 1937 - 1938 - 1939 1940 1941
Year 1938 (MCMXXXVIII
..... Click the link for more information.
Doming is a phenomenon found on some CRT televisions in which parts of the shadow mask become heated. In televisions that exhibit this behavior, it tends to occur in high-contrast scenes in which there is a largely dark scene with one or more localized dark spots.
..... Click the link for more information.
..... Click the link for more information.
Invar, also called FeNi, is an alloy of iron (64%) and nickel (36%) with some carbon and chromium. This alloy is known for its unique properties of controlled coefficient of thermal expansion (CTE).
..... Click the link for more information.
..... Click the link for more information.
Centuries: 19th century - 20th century - 21st century
1960s 1970s 1980s - 1990s - 2000s 2010s 2020s
1990 1991 1992 1993 1994
1995 1996 1997 1998 1999
- -
-
..... Click the link for more information.
1960s 1970s 1980s - 1990s - 2000s 2010s 2020s
1990 1991 1992 1993 1994
1995 1996 1997 1998 1999
- -
-
For the band, see .
..... Click the link for more information.
liquid crystal display (commonly abbreviated LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector.
..... Click the link for more information.
..... Click the link for more information.
Dot pitch (sometimes called line pitch, phosphor pitch or pixel pitch) is a specification for a computer display that describes the distance between phosphor dots (sub-pixels) or LCD cells of the same color on the inside of a display screen.
..... Click the link for more information.
..... Click the link for more information.
This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.
Herod_Archelaus
