| Item |
Description |
| |
|
| Active Area/Effective Area |
Perimeter dimensions of the conductive area, within the
viewing area of the LCD glass.
|
Active Matrix TFT
|
type of LCD, used in most laptops, and most LCD panels and
projectors. A typical active matrix TFT displays are noted
for their quick response time and their ability to display
full motion video and animations without image ghosting |
Alignment Layer
|
A layer and/or surface treatment applied to the boundary
of a liquid crystal cell to induce a particular director orientation.
For example, a layer of polyimide buffed in one direction
induces alignment parallel to the buffing direction |
Amorphous
|
Irregular; having no discernible order or shape. In the
context of solids, the molecules are randomly arranged, as
in glass, rather than periodically arranged, as in a crystalline
material |
Amorphous Silicon (aSi)
|
|
Anisotropic
|
Having properties which vary depending on the direction
of measurement. In liquid crystals, this is due to the alignment
and the shape of the molecules |
Annunciator
|
An active element, such as a symbol, word, or phrase. |
Aperture Ratio
|
|
Aspect Ratio
|
The ratio of the width of the display to the height of the
display eg VGA 640 x 480 is a 4:3 format (480 x 4/3 = 640) |
Bezel
|
A metal or plastic frame which fits over the LCD glass.
The bezel acts as a pressure device, compressing the elastomer
connector between the LCD glass and PCB |
Black Matrix
|
|
Brightness
|
The attribute of visual perception in accordance with which
an area appears to emit more or less light. (Luminance is
the recommended name for the photo-electric quantity which
has also been called brightness.) |
Buffing
|
To give the inner glass surfaces of a liquid crystal cell
a texture so as to align the liquid crystal molecules in a
certain direction parallel to the surfaces |
Cell Gap
|
The spacing between the two pieces of glass. This space
contains the liquid crystal fluid. |
Chip on Board (COB)
|
The LCD driver is formatted into an area on the PCB. Electrical
connections are made by micro diameter gold wires. |
Chip on Glass (COG)
|
Recent technology development, where the LCD driver is mounted
directly on the LCD glass substrate. |
Chip on Flex (COF)
|
The LCD driver is incorporated into a flex connector, which
is attached to the contact edge of the LCD glass |
Cold Cathode Fluorescent Lamp (CCFL)
|
A type of fluorescent backlighting or edge lighting. Used
in small, medium and large size graphic LCD modules. |
Colour Filter
|
|
Colour Temperature
|
A method of measuring the "whiteness" of a light
source. |
Common Interface Format (CIF)
|
Developed to support video conferencing. CIF has an active
resolution of 352 x 288 and a refresh rate of 29.97 frames
per second. Quarter CIF (QCIF) has a resolution of 144 x 176.
QCIF+ has a resolution of 220 x 176. High definition CIF (HDCIF)
is used for HDTV production and distribution having a resolution
of 1920 x 1080. |
| Common/Backplane |
The conductive surface on one of the two pieces of glass,
which superimposes the pattern on the second piece of glass.
The number of backplanes corresponds to the duty ratio. |
Component Video
|
a method of delivering quality video (RGB) in a format that
contains all the components of the original image. These components
are referred to as luma and chroma and are defined as Y'Pb'Pr'
for analog component and Y'Cb'Cr' for digital component. Component
video is available on some DVD players and projectors. |
Composite Video
|
The combined picture signal, including vertical and horizontal
blanking and synchronising signals |
Contact Edge
|
The extended area of the LCD glass which contains the conductive
leads/traces, to which electrical connections is made by a
connector. |
Contrast ratio
|
The difference in luminance between the unselected area
and the selected area. |
Colour STN
|
|
| Cursor |
A row or block of dots, used to indicate the location of
the next character or symbol to be entered. Used in dot matrix
character and graphic LCD modules. |
Digital Video Interface (DVI)
|
A standard that defines the digital interface between digital
devices such as projectors and personal computers. For devices
that support DVI, a digital to digital connection can be made
that eliminates the conversion to analog and thereby delivers
an unblemished image. |
Direct/Static Drive
|
Each conductive lead on the contact edge, connects to one
segment or annunciator. |
| Dot/Pixel |
Typically a rectangular active element, when combined together
in a matrix, forms a character, symbol or dot matrix |
Dot Matrix
|
A group of dots/pixels forming a matrix. |
| Duty Ratio |
1/N, where N equals the number of energised or unenergized
rows selected by one complete cycle. |
Elastomers
|
A class of polymers that have some degree of cross linking
and are rubbery. Elastomers possess memory, that is, they
return to their original shape after a stress is applied.
|
Elastomer Connector
|
A strip of silicone rubber made up of sequentially spaced
conductive and non-conductive material. This is the most common
connection method for LCD modules. |
| Electroluminescent Lamp |
Is a thin membrane consisting of two coated electrode plates
with an aluminium reflector. When AC voltage is applied to
the electrodes, the electrons collide with the light emission
core. The energy given off is light. |
Fill Hole
|
A space left between the epoxy seals, after assembly on
one end of the LCD glass. This space is used to fill the glass
with the LC fluid, which is noted by a mound of epoxy on one
end of the glass. |
Film STN
|
|
Flat Panel Display (FPD)
|
|
Ghosting
|
A phenomenon which occurs when voltage from an energised
element leaks to an adjacent OFF element and turns the adjacent
element partially ON. |
Heat Seal
|
A flat, flexible, adhesive connector which is bonded to
the contact edge of the glass by heat. Typically used on large
graphic modules. |
Inverter (DC to AC)
|
Used to power electroluminescent lamps. Converts DC to AC
voltage at a high frequency 300Hz ~1khz. |
Inverse/Reverse Image
|
Used exclusively on negative image graphic displays (transmissive
negative). With EL or cold cathode backlight where the background
is energised and the information to be displayed remains static
or the same colour as the polariser in the OFF state. This
is achieved by inverting the signal of the data lines before
going to the LCD module. |
Isotropic Stage
|
When the fluid heats up or cools down to the point where
the fluid is no longer in the twisted nematic state. The molecules
can no longer twist light and, therefore, all incoming light
is absorbed. In positive image displays, the viewing area
turns completely dark. The display will revert back to the
twisted nematic state when cooled below the isotropic temperature. |
LED Backlight
|
A form of backlighting for small to medium size LCDs that
use surface mount LEDs on a substrate with a light diffuser
over the top. In some cases LEDs are placed at each end of
the module and light is directed into the centre. |
Liquid Crystal Fluid
|
Has properties of both a fluid and solid. Consisting of
rod shaped, bipolar molecules, which in the OFF state are
capable of twisting polarised light. |
Liquid Crystal Display (LCD)
|
|
Liquid Crystal Module (LCM)
|
|
Low Voltage Differential Signal (LVDS)
|
|
| |
|
Module
|
Consists of LCD (glass) connected to a PCB with drivers
on board. Controllers, temperature compensation circuits,
etc., are optional. |
Multiplex
|
Using multiple backplanes (commons) in order to reduce the
number of connections between the drivers and the LCD. |
Negative Image
|
The viewing area is a dark colour in the OFF state. This
condition is achieved by having both front and rear polarisers
in the same axis. In this mode, light passes through the energised
areas. Some type of backlight must be used in order to effectively
view the information. |
Nematic
|
|
PanelLink
|
An all digital interface used to transmit computer video
from a PC/Notebook to a projector. Supports resolutions from
640x480(VGA) up to 1600x1200(UXGA). |
Persistence
|
The amount of time a phosphor or diode pixel stays lit after
current has been applied to it. A pixel's persistence is what
allows an image to remain on the screen between screen refreshes.
Screens with short persistence may show flicker, while thiose
with long persistence may show ghosting |
Pitch
|
|
Polarisers
|
|
Poly Silicon (pSi)
|
|
Positive Image
|
Active elements, when energised, appear dark in colour against
a light background (non-energised); i.e., reflective, transflective,
transmissive, (positive) inverse image. |
| Quarter Common Interface Format (QCIF) |
|
Quarter VGA (QVGA)
|
|
| Retardation Film |
A thin (100 microns thick) piece of material laminated to
the rear polariser. Function is to change normal blue coloured
dots to black. Used on supertwist graphic modules with a CFL
light source. Commonly referred to as black and white. |
Reflective
|
Typically a smooth silver/grey piece of polished aluminium
foil bonded to the rear polariser. Reflects the incoming ambient
light. Note: Backlighting can not be used with a reflective
type LCD. |
Refresh
|
|
Resolution
|
|
Response Time (Toff)
|
Total of delay time (Td off) and rise time Tr. |
Response Time (Ton)
|
Total of rise time Tr and delay time Td on: Time interval
between 10%(on) to 90%(on). |
Saturation Voltage
|
RMS voltage required to turn fluid to 90%(on). |
Segment
|
An active element of a digit (i.e., typically numeric digits
have 7 segments and alpha/numeric digits can have 14 or 16
segments). |
Supertwisted Nematic (STN)
|
An improved twisted nematic fluid (200° twist or greater)
which has better contrast and optimum viewing range than standard
twisted nematic (90°). Acronyms - SBE, New TN; NTN; SNTN. |
Tape Automated Bonding (TAB)
|
LCD driver or controller electronics are encapsulated in
a thin, hard bubble package, of which the drive leads extend
from the bubble package on a thin plastic substrate. The adhesive
along the edges is used to attach the TAB to the LCD glass
and/or PCB. |
Tape Carrier Package (TCP)
|
|
Thin Film Transistor (TFT)
|
|
Threshold Voltage
|
RMS voltage required to turn fluid to 10%(on). |
Transflective
|
A type of backing which is bonded to the rear polariser.
Enables light to pass through the back, as well as reflecting
light from the front. |
Transmissive
|
A type of LCD which does not have a reflector or transflector
laminated to the rear polariser. A backlight must be used
with this type of LCD configuration. Most common is transmissive
negative image. |
Twisted Nematic (TN)
|
A type of liquid crystal whereas the alignment surface and
therefore the LC molecules are oriented 90° from each
surface of glass. |
UL
|
End products can be Listed by Underwriters Laboratories
for expected safety concerns |
Uniformity
|
|
Viewing Angle
|
A cone perpendicular to the LCD in which minimum contrast
ratio can be seen. |
Viewing Area
|
The dimensions measured from the inside perimeter of
the LCD bezel or LCD glass epoxy seal. |
Viewing Mode
|
|
Zebra Connector
|
See Elastomer Connector |
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