Glossary
the Display Future world
|
| Products
|
| Active Area |
Physical glass area occupied by Liquid Crystal.
AA= n x Dot Pitch + Dot Size, where n is the number of pixel on any axis. |
| AMEPD |
Active Matrix Electrophoretic Display.
Better known as E-paper displays, AMEPD are based on titanium dioxide and hydrocarbon oil technology. |
| AMOLED |
Active-Matrix OLED. OLED with TFT layer. |
| Array BLU |
Matrix of LEDs located on the back of glasses,
about 5 mm thick. Price and power consumption depend on the number of LEDs employed.
Homogeneous luminosity. |
| Bias |
Lowest voltage level for multiplexed voltage
methods. Indicates the number of driving voltage levels: with bias=1/x, there are x+1 driving voltage
levels (1, 1/2, 1/3 ... 1/x times the max voltage level). Bias is correlated to Duty
value. |
| BL/BLU |
BackLight Unit. Light source for TFT and LCD
trasmissive/trasflective. BLU definition includes BLU source (LEDs, EL or CCFL) and
light guide. |
| Booster |
Electronic device that generates all voltage
levels (Bias) for the multiplexed voltage methods. Sometimes it is integrated into
IC controller, sometimes requires addition of external capacitors. |
| Brightness |
The amount of light emitted from the display. |
| CCFL |
Cold Cathode Fluorescent Lamp. Low power and
bright white light source, with life-time up to 30,000 hours. Requires light-guide
and DC/AC converter. |
| COB |
Chip On Board. The ICs are on PCB. It requires
a mounting media to both electrically and physically connect the PCB to the glass. |
| COF |
Chip On Film. Technology on FPC for IC and
other electronic components. Minimize display sizes. More robust than TAB but bigger
pads/tracks pitch. |
| COG |
Chip On Glass. The glass of the display is the
physical support for the IC, therefore the glass surface needs to be few millimeter bigger
in one axis to accommodate IC. |
| Color LCD |
LCD with different color areas. Color filter,
color screen print or color polarizer are used. |
| Connector |
Method/support part that connects display
module to the application. From the module: pins, Heat-Seals, FFC, COF end, TAB end, exposed pads/tracks and through holes.
From application: ZIF, LIF, through hole, pins and exposed pads/tracks. |
| Contrast Ratio |
The ratio between the luminosities of the brightest
and the darkest point that the module is capable of producing. |
| Crosstalk |
Visible defect that occurs because of
interference by adjacent pixels of segment/common. |
| CSTN |
Color STN. They employ RGB pixels. Different technology than (area) Color LCD. |
| DC/AC Converter |
Amplifier circuit that converts DC to AC voltage, used to power CCFL and EL back lights. |
| Die |
Unpackaged IC. Plural: dies or dice. |
| DIP |
Dual In Line. |
| Dot Pitch |
Corresponds to the dimensions of a pixel plus
the gap between a pixel and the one. |
| Dot Size |
Dimesions of a single pixel. |
| Duty |
Multiplexing index for multiplexed voltage
method: used to reduce the number of ITO tracks and inter-connector lines. Duty= 1/y,
means 1 lines activates y segments. Higher duty comes with less contrast quality. |
| Edge BLU |
LEDs in-line, usually embedded in the
light-guide. Homogeneity of light depend on light-guide quality, however inferior
than Array BLU (more expensive though). |
| EL |
Electro-Luminescence. Thin BLU located on
the back of glass, with homogeneous but no extremely bright emission; life time:
2~3,000 hours. Low power consumption but they require DC/AC converter. Good color
variety. |
| E-paper displays |
Type of screens technically known as AMEPD. |
| ESD |
Electro-Static Discharge. ESD is a major cause
of failure in electronic components. Human body and activity are common sources of
ESD. |
| FFC |
Flat Flexible Cable. |
| FPC |
Flexible Printed Circuit. General definition
for COF, FFC TAB and TCP. |
| FPD |
Flat Panel Displays. |
| FSTN |
Film Super Twisted Nematic. Compensation
RCF (Retardation Control Film) is used to achieve black dot on white color. Usual
color: (positive) dark-blue dot on light-grey or yellow/green; (negative) white
dot on blue. |
| Ghosting |
A condition where "off" segments become
slightly visible. |
| Glare filter |
Additional anti-reflective filter to improve
viewability in harsh lighting conditions. |
| Heat-Seals |
Mounting method and connector type. Flexible
support with interface tabs made of a conductive hot melt adhesive. Connection
requires pressing hot bar. |
| Hot-Spot |
Undesired bright spots that cause inhomogeneous
luminosity, usually due to not perfectly designed light-guide. |
| HTN |
Higher Twisted Nematic. Their crystal
molecules have a higher twisted angle than TN, thus provide clearer visibility and
wider viewing angle. |
| I/O |
Input/Output. |
| Inter-connector |
Mounting method/support that connects glass
to the rest of display module. Zebra, pins, heat-seals. |
| ITO |
Indium Tin Oxide. It is transparent and
colorless in thin conductor layers, used as signal carrier on glass for pixels
activation. |
| LCD |
Liquid Crystal Display: liquid crystal
sits within a pair of transparent electrodes. |
| LCM |
LCD Module. LCD glass with controllers or/and
drivers circuit, inter-connector, possibly with BLU and connector. |
| LED |
Light Emitting Diode. Source unit for BLU
with minimum 50,000 life time. Broad color variety. |
| LIF |
Low Insertion Force. |
| Light-Guide |
Light diffuser located between BLU source and
glass, it scatters light homogeneously over the View Area. Usually included into BLU
definition. |
| NRE |
Non-Recurring Engineering refers to the one-time cost to research, develop, design and test a new product. |
| OEL |
Organic ElectroLuminescence. OLED synonymous. |
| OLED |
Organic LED. Emissive display technology
(do not require BLU) that comprises a film of organic compounds. Wide 160' Viewing
Angle and stunning definition for both monochromatic and color display. High
brightness and low power consumption. |
| PCB |
Printed Circuit Board. |
| PDP |
Plasma Display Panels. |
| Pin |
Inter-connector for COB or connector for low
I/O display; it can be straight or banded. In COB pins connect glass to PCB; in glass or COG,
pins connect LCM to the application board. Pins pinch the glass upon ITO tracks and
can be soldered at the other end. Robust but pin pitch can't be as little
as other mounting methods. |
| PLED |
Polymer LED. OLED synonymous. |
| Polarizer |
A stretched polymer which transmits light in
only one axis. A typical display has polarizer on the front and back. |
| PPI |
Pixels Per Inch. Measurement of pixel
density of a display. |
| Reflective |
A viewing mode which uses ambient front
lighting to provide the illumination for the display. Reflective displays do not
support backlight and can be only positive mode. |
| SMD |
Surface Mount Device. |
| SMT |
Surface Mount Technology. |
| SOIC |
Small Outline IC. |
| STN |
Super Twisted Nematic. Their crystal
molecules have a higher twisted angle than HTN. For high-duty drive LCD. |
| TAB |
Tape Automated Bonding. Technology on FPC
for IC only. Smaller pads/tracks pitch than COF, but less robust though. Minimize
display sizes. Smaller pads/tracks pitch than COF, less robust though. External
connectors: FPC or Heat-Seals. |
| TCP |
Tape Carrier Package, technology FPC . |
| Temperature |
Operating temperatures: Standard about 0 C
to +50 C; wide about -20 C to +70 C; very wide about -40 C to +90 C for TN or -40 C
to +80 C for other technologies. Storage temperature: ranges about -10 C and + 10 C
wider than working temperatures. |
| TFT |
Thin Film Transistor. Active-Matrix (but not active display) variant
of color LCD technology. Negative displays with high brightness and wide viewing
angle. Broadly used as mobile phone displays. |
| TN |
Twisted Nematic. The simplest and cheapest crystal technology for low duty displays. Limited viewing angle. |
| Transflective |
A viewing mode which uses both back-lit and ambient
light reflection. Tansflective displays can be either negative or positive mode. |
| Trasmissive |
The only emission light is back-lit. Trasmissive
displays can be either negative or positive mode. |
| TSSOP |
Thin Shrink Small Outline Package. |
| View Area |
Glass area which is visible through a bezel
or cut-out in an application device. This area is made up of the Active Area and a
boarder around the Active Area. |
| Viewing Angle |
Viewing angle is the maximum angle at which
a display can be viewed with acceptable definition. |
| Y-G |
Yellow-Green color. |
| Zebra |
Elastomeric (rubber) conductive strip used
on COB module to electrically connect board exposure contacts to ITO tracks.
Mechanically robust but adds extra thickness to LCM. It requires bezel for physical
anchoring to PCB. |
| ZIF |
Zero Insertion Force. |
