| AM-LCD |
Active-Matrix Liquid Crystal Display.
An LCD (see separate definition) where each pixel is
individually controlled by a switch, realized via a
Thin-Film Transistor (TFT). For the opposite case, a
Passive-Matrix LCD, each pixel is passively addressed.
|
AM-OLED
|
Active-Matrix Organic Light Emitting Diode
(display). An OLED display (see separate definition)
where each pixel is individually controlled by a switch,
realized via a Thin-Film Transistor (TFT). The opposite
case, a Passive-Matrix OLED is when each pixel is passively
addressed. |
Aperture Ratio (optical)
|
Ratio of the pixel in a TFT that is un-obscured
by the transistor or bus lines i.e. the area that will
actually allow light to pass through. |
| a-Si |
Amorphous silicon. Opposite to crystalline silicon, where the silicon material on atomic scale has a perfect crystall lattice, amorphous silicon material consists of very small regions which, each which have a crystalline structure, but with large discontinuities on the border between each border. |
Back-light
|
All LCD's require a light source to operate , either ambient light in the case of a reflective LCD or an artificial one in the case of transmissive/transflective displays. A backlight is where a light source is positioned directly behind the LCD itself and gives optimum performance although adding greatly to the thickness. Typically CCFL, EL and LED's are used. |
Chip-on-Flex / Foil (COF)
|
LCD module construction technique whereby the driver chip is again supplied in die form and attached to a flexible foil negating the need for any PCB. Useful where a reflective , low cost construction is required. Additional circuitry can also be included and the foil can be reasonably large. |
Chip-on-Glass (COG)
|
LCD module construction technique whereby the driver chip is supplied in die form and assembled directly onto the cell itself. Not only does this reduce costs and increases reliability it also reduces the number of connections between the cell and the rest of the assembly. |
Colour Depth
|
Definition of the colour capability of
a given display.Based on the number of bits of information
per pixel , with 1 bit the pixel is either ON or OFF
, with 2-bits there are 4 choices/levels and with 3-bits
there are 8 levels etc. |
Colour STN (CSTN)
|
Colour variant of STN, the most common
passive mode LCD technology.Colour produced by each
dot comprising 3 smaller pixels incorporating colour
filters to give RGB when using a white backlight. |
Contrast Ratio (CR)
|
Comparison of the luminance of a pixel
in the ON state to one in the OFF state. The higher
the ratio the better. |
DSTN
|
Double (layer/cell) STN. Enables the colour
effect of a typical STN cell ( typically yellow) to
be removed by passing the light through another layer
to achieve a black/white contrast effect. Later replaced
by FSTN in most monochrome displays, although still
used regularly in the automotive arena. |
Emissive display
|
Any display that actually generates or
emits light eg. VFD or plasma in FPD's and the CRT. |
In-cell Diffusing Reflector (IDR)
|
Best performing reflective TFT construction
whereby the reflector is included within the display
itself. |
ITO
|
Indium Tin Oxide , typically the transparent
conductor material of most LCD's. |
Light Emitting Diode (LED)
|
In flat panel displays this solid state,
semiconducting , light producing device is used for
either back or frontlighting systems. Available in a
number of colours , including Red,Green and Blue. It
is not available as a 'white' device.White LED's can
be produced by incorporating RGB chips into 1 package.
this cannot be used a as a 'white' backlight however
due to the colour filter construction of all colour
LCD's |
Light guide
|
In LCD's this is generally a plastic assembly
that transmits and conducts light across a larger display
area from a single or multiple 'point' light source. |
Liquid Crystal Display (LCD)
|
Most common form of flat panel display.
Construction is 2 layers of glass (or more recently
possibly plastic) enclosing a layer of liquid crystal
material. When a voltage is applied across the LC the
crystals twist to either block or transmit light. |
LTPS
|
Low Temperature Poly Silicon. Type of
TFT technology for active matrix displays, enabling
higher resolution displays where the drive circuitry
is included on silicon on the display substrate. It
is grown out of amorphous silicon material, typically
by a process called Excimer Laser Annealing, which locally
heats up the amorphous silicon, such that larger crystalline
areas are formed. |
Luminance
|
The measure of the light intensity of
the display , sometimes called brightness.See luminous
intensity/candela/lumen. Not to be confused with Illuminance. |
Multidomain Vertically Aligned (MVA)
|
A Liquid Crystal mode which allows for
high contrast, wide viewing angles, and can completely
eliminate grey scale inversion. |