Active-matrix liquid crystal display
Encyclopedia
An active matrix
liquid crystal display
(AMLCD) is a type of flat panel display
, currently the overwhelming choice of notebook computer manufacturers, due to low weight, very good image quality, wide color gamut
and response time. The first functional AMLCD display was made by by Dr T Peter Brody
at Westinghouse Electric Corporation in 1973.
on the display while all the other pixels are being updated. This method provides a much brighter, sharper display than a passive matrix of the same size. An important specification for these displays is their viewing-angle.
Thin-film transistor
s are usually used for constructing an active matrix
so that the two terms are often interchanged, even though a thin film transistor is just one component in an active matrix and some active-matrix designs have used other components such as diode
s. Whereas a passive matrix display uses a simple conductive grid to deliver current to the liquid crystals in the target area, an active-matrix display uses a grid of transistors and capacitors with the ability to hold a charge for a limited period of time. Because of the switching action of transistors, only the desired pixel receives a charge, and the pixel acts as a capacitor to hold the charge until the next refresh cycle, improving image quality over a passive matrix.
Active matrix
Active matrix is a type of addressing scheme used in flat panel displays. The term describes a method of switching individual elements of a flat panel display, using a CdSe or Silicon-based thin-film transistor for each pixel...
liquid crystal display
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
(AMLCD) is a type of flat panel display
Flat panel display
Flat panel displays encompass a growing number of electronic visual display technologies. They are far lighter and thinner than traditional television sets and video displays that use cathode ray tubes , and are usually less than thick...
, currently the overwhelming choice of notebook computer manufacturers, due to low weight, very good image quality, wide color gamut
Gamut
In color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a...
and response time. The first functional AMLCD display was made by by Dr T Peter Brody
T Peter Brody
T. P. "Peter" Brody , was a British-naturalised physicist and the inventor of Active Matrix Thin-Film Transistor display technology, having produced the world's first Active Matrix Liquid Crystal Display in 1972 and the first functional AM-EL in 1973 while employed by Westinghouse Electric...
at Westinghouse Electric Corporation in 1973.
Introduction
The most common type of LCD display contains, besides the polarizing sheets and cells of liquid crystal, a matrix of TFTs to make a TFT-LCD. These devices store the electrical state of each pixelPixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
on the display while all the other pixels are being updated. This method provides a much brighter, sharper display than a passive matrix of the same size. An important specification for these displays is their viewing-angle.
Thin-film transistor
Thin-film transistor
A thin-film transistor is a special kind of field-effect transistor made by depositing thin films of a semiconductor active layer as well as the dielectric layer and metallic contacts over a supporting substrate. A common substrate is glass, since the primary application of TFTs is in liquid...
s are usually used for constructing an active matrix
Active matrix
Active matrix is a type of addressing scheme used in flat panel displays. The term describes a method of switching individual elements of a flat panel display, using a CdSe or Silicon-based thin-film transistor for each pixel...
so that the two terms are often interchanged, even though a thin film transistor is just one component in an active matrix and some active-matrix designs have used other components such as diode
Diode
In electronics, a diode is a type of two-terminal electronic component with a nonlinear current–voltage characteristic. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material connected to two electrical terminals...
s. Whereas a passive matrix display uses a simple conductive grid to deliver current to the liquid crystals in the target area, an active-matrix display uses a grid of transistors and capacitors with the ability to hold a charge for a limited period of time. Because of the switching action of transistors, only the desired pixel receives a charge, and the pixel acts as a capacitor to hold the charge until the next refresh cycle, improving image quality over a passive matrix.
See also
- Liquid crystal displayLiquid crystal displayA liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
- Active matrixActive matrixActive matrix is a type of addressing scheme used in flat panel displays. The term describes a method of switching individual elements of a flat panel display, using a CdSe or Silicon-based thin-film transistor for each pixel...
- Organic light-emitting diodeOrganic light-emitting diodeAn OLED is a light-emitting diode in which the emissive electroluminescent layer is a film of organic compounds which emit light in response to an electric current. This layer of organic semiconductor material is situated between two electrodes...
- Display resolutionDisplay resolutionThe display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...