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Glossary of Terms

Midas Components

¼ VGA

Resolution of 320 X 240 dots.

½ VGA

Resolution of 640 X 240 dots.

8 Bit Interface

Display is driven with 8 data bus lines.

16 Bit Interface

Display is driven over 16 data bus lines.

Active Area

In the viewing area of the LCD glass, the dimensions of the perimeter of the conductive area.

Bezel

A frame of plastic or metal, fitting over the LCD glass, to protect the edges of the glass and act as a pressure device, compressing the elastomer connector between the PCB and LCD glass.

Backlight (B/L)

A light source that is placed behind the display to make the display readable in poor/no light situations.

CCFL

Cold cathode fluorescent lamp. Previously used for backlights in displays.

Chip-on-board (COB)

The LCD driver wafer is mounted on the PCB with gold wires used to connect it to other circuits. It is covered with epoxy.

Chip-on-glass (COG)

Technology that mounts the LCD driver to the contact edge of the LCD glass.

Cover Glass

A screen applied over a display to improve various aspects of performance, including damage resistance and sunlight resistance.

Common / Backplane

The superimposition of the conductive pattern from one piece of glass to the second piece. The duty ratio is determined by the number of backplanes.

Cold Cathode Fluorescent (CCFL)

In medium to large LCD graphic modules, a type of fluorescent backlighting or edge lighting.

Contact Edge

The area of the LCD with conductive leads/traces where electrical connection is made by use of a connector.

Contrast Ratio

The difference in luminance between the unselected area and the selected area.

Crosstalk 

Crosstalk is the defect produced by the interference of the adjacent pixels. The contrast of these crosstalk areas is different from other areas. Crosstalk can appear only with certain display patterns.

CTP

Capacitive touch panel.

Cursor

Dots used to indicate the location of the next character or symbol to be entered.

DIL (Dual-In-Line)

Two parallel rows of connection holes on a PCB. Also, the type of connector used with this array.

Direct / Static Drive

The method in which each conductive lead on the contact edge connects to one segment or annunciator.

Dot Gap

The space containing liquid crystal fluid between the two pieces of glass.

Dot / Pixel

An active element that forms a character or symbol when combined in a matrix.

Dot Matrix

A group of dots/pixels forming a character or symbol, usually five dots across and seven dots down.

Double Film Compensated Super Twisted Nematic (FFSTN) 

This display type is the same as the FSTN, the only difference is that it has double the compensation film.

DSI

Display serial interface.

Duty Ratio

1/N when N is equal to the number of segments selected by one complete cycle.

Edge Lighting

A backlight in which the tube(s) are located at the side of the display and uses a light guide to get even lighting across the display, which allows for thinner displays.

EL Backlight

A type of backlight using electroluminescent material. The thinnest available backlight. Electroluminescent can also be a type of display.

Elastomer Connector

A silicone rubber strip made up of sequentially spaced conductive and non-conductive material. The most common method of connection for LCD modules.

Fill Hole

The space left between the epoxy seals on one end of the LCD glass after assembly. This space, used to fill the glass with the liquid crystal fluid, is noted by a mound of epoxy.

Font

The active pattern containing the information to be displayed in the LCD glass.

Film Compensated Super Twisted Nematic (FSTN)

This display uses an optical retarder to eliminate elliptical polarization from STN display.

Ghosted

A phenomenon occurring when voltage from an energized element leaks to an adjacent OFF element and turns the adjacent element partially ON.

Grey Scale

Greyscale is a range of shades of grey without apparent colour. The darkest possible shade is black, which is the total absence of transmitted or reflected light. The lightest possible shade is white, the total transmission or reflection of light at all visible wavelengths. Intermediate shades of grey are represented by equal brightness levels of the three primary colours (red, green and blue) for transmitted light, or equal amounts of the three primary pigments (cyan, magenta and yellow) for reflected light.

HDMI

High-definition multimedia interface.

Heat Seal

A flexible adhesive connector bonded by heat to the contact edge of the glass.

IPS

In Plane Switching is a display technology that gives all round viewing angles.

Interconnect Dot

Consisting of silver impregnated epoxy, it connects the pattern piece of glass to each backplane.

Inverter, DC to AC

Converts DC to AC at a high frequency, and powers electroluminescent lamps.

Leads

The conductive traces on the contact edge of the glass.

Liquid Crystal Fluid

Having properties of both a solid and a liquid, it consists of rod-shaped bipolar molecules which are capable of twisting polarized light when in the OFF state.

LVDS

Low voltage differential signalling. Used for long distance control.

MCU

Micro Controller Unit. Basic controller, generally found on small TFTs.

MIP

Memory-in-Pixel.

MIPI

Mobile industry processor interface.

Module

An LCD glass connected to a PCB with drivers on board. It may also have controllers, temperature compensation circuits, or other features.

Multiplex

Using multiple backplanes in order to reduce the number of connections between the LCD and the drivers.

Negative Mode

Light characters or dots on a dark background.

O-Film

A film that can be added to a display to give it greater viewing angles.

PCAP

Projective capacitive touch panel.

Pitch

The centre dimension of adjacent conductive traces, dots, or connector holes.

Positive Mode

Dark characters or dots on a light background.

Reflective

A smooth silver piece of aluminium foil, bonded to the rear polarizer, which reflects incoming ambient light. Backlighting cannot be used with a reflective LCD.

RGB Interface

Can be 16-bit, 18-bit, or 24-bit. The display has no on-board memory mapped controller and will require a PIC.

RMTS

Resistive Multi Touch Screen.

RTP

Resistive Touch Panel.

Saturation Voltage

RMS voltage required to turn fluid to 90% on.

Segment

An active element of a digit, usually 7 segments for numeric and 14 segments for alpha/numeric digits.

SIL (Single-In-Line)

An LCD module that has a single row of connection holes, and an LCD glass with a single contact edge.

Super Twisted Nematic (STN)

The structure of STN is similar to TN but with 180 to 270 twist. The higher twist gives better contrast and viewing angle for highly multiplexed applications.

SVGA

Resolution of 800 X 600 dots.

SXGA

Resolution of 1280 X 1024 dots.

Tape Automated Bonding (TAB)

Chip mounted to the flat flexi of the display.

TFT

Thin film transistor.

Threshold Voltage

RMS voltage required to turn fluid to 10% on.

Touch Screen / Panel (TP)

A transparent glass or hard plastic sheet that mounts over the display viewing area and allows users to input using the screen.

Transflective

A type of backing, bonded to the rear polarizer, which enables light to pass through the back as well as reflecting light from the front.

Transmissive

An LCD which does not have a reflector or transflector laminated to the rear polarizer. A backlight must be used with this type of LCD configuration.

Twisted Nematic (TN)

In a quiescent state, display has a 90° twist in the alignment of the liquid crystal molecules at the transition between the surfaces of the two glass substrates.

UART

Universal Asynchronous Receiver/Transmitter is an interface used to control a serial interfaced display module.

UHD

Ultra-high definition. 7680 X 4320 pixels.

USB

Universal serial bus.

VGA

Resolution of 640 X 480 dots.

Viewing Angle

A cone perpendicular to the LCD in which minimum contrast can be seen.

Viewing Area

The dimensions measured from the inside perimeter of the LCD bezel or LCD glass epoxy seal.

Vertical Alignment twisted Nematic (VATN)

Liquid crystals align vertically when the voltage is zero, this creates a true black background on the display.

Wide VGA (WVGA)

Resolution of 800 X 480 dots.

Wide ¼ VGA (WQVGA)

Resolution of 480 X 272 dots.

XGA

Resolution of 1024 X 768 dots.

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