Displays

CRT

A ___ consists of a picture tube with an electron gun that fires electron beams at a screen. Before reaching the screen, the electrons pass through a shadow mask. This determines where electrons hit the screen, creating phosphor dots.

CRT

A beam of electrons strikes the phosphorous coating on the screen. The coating then glows for a fraction of a second. The electrons must strike the phosphorous coating many times to keep it glowing.

DLP projectors

Digital light processing - or DLP for short - was developed by Texas Instruments, and uses a semiconductor chip known as a digital micromirror device, or DMD. The DMD consists of hundreds of thousands of miniature pivoting mirrors - one for each pixel - that are used to reflect red, green, and blue light to a screen to form images.

dot pitch

Dot pitch is the predefined measurement in millimeters between pixels on a screen. The lower the number, the clearer the display. A typical dot pitch is 0.27 millimeters.

vertical and horizontal size, centering, and convergence

You use size and centering settings to ensure that the display area reaches the edges of the screen. Convergence refers to the horizontal and vertical alignment of colors displayed on the screen. You can generally set vertical and horizontal size, centering, and convergence using the buttons on a monitor.

LCD

a backlighting source passes light through liquid crystals to create the three colors - red, blue, and green - that determine the resulting color of each pixel.

plasma

screen contains front and rear plate glass, a dielectric layer with a magnesium oxide coating, display electrodes, with phosphor coating of plasma cells, and an address electrode and address protective layer.

USB hub

A Universal Serial Bus - or USB - hub is a component some manufacturers add to LCD monitors. A self-powered, rather than bus-powered, hub offers mobile users system-connected ports into which they can plug USB devices such as printers or flash drives, without having to be mindful of power constraints.

S-video

A legacy technology designed for a standard video, or SD, applications, S-video connectors separate brightness and color information into two paths. The basic S-video connector is a 4-pin mini-DIN connector. This connector can fit into a 7-pin female S-video connector, but the 7-pin male connector isn't compatible with a 4-pin female connector.

active matrix

Active matrix displays produce sharper images and have a higher refresh rates. In these displays, transistors behind each pixel stimulate electrodes that rearrange the liquid crystals. Active matrix displays are also known as Thin Film Transistor - or TFT - displays.

LCD projectors

An LCD projector consists of a lamp, beam-splitting mirrors, and three polysilicone panels. When light passes through the mirrors, the beam is split into pure red, green, or blue light. Each color of light is then passed through a dedicated panel. Each color-specific panel consists of thousands of pixels, which will be either opened or closed with the use of electrical currents. After passing through the panels, the three colors are combined using a prism and finally projected through the projector's lens. This is known as transmissive technology.

anti-theft lock

An anti-theft lock, such as those found on notebook computers, is included with some LCD monitors. A standard locking device fits into a slot. Locking the device turns a metal bar perpendicular to the slot. In addition, the Video Electronics Standards Association - or VESA - organization includes specifications for LCD monitors that can be wall-mounted.

aspect ratio

Aspect ratio refers to the relationship between the horizontal size of a screen and its vertical size. A standard CRT monitor has an aspect ratio of 4 to 3. Widescreen monitors use a 16 to 9 aspect ratio. Aspect ratio is often denoted with a colon, for instance 16:9.

brightness

Brightness or luminescence is the measurement in candelas per square meter of light produced by an LCD monitor. The typical range is 250 to 500 cd/m2, although 250 to 300 cd/m2 is adequate for most tasks. Brighter monitors are better for movies and games. Candelas per square meter of light is abbreviated to cd/m2.

component cable

Component cables are HD capable analog video connectors comprised of three RCA connectors. These are similar to regular red, green, and blue, or RGB, video connectors. The RCA connectors create a separate signal for the colorless part of the stream called luminance whereas RGB connectors combine black and white information with the RGB streams. Two other color difference signals are created. They are Pb - blue minus luminance - and Pr - red minus luminance, and are derived from the RGB separation. Combined, the three signals produce an approximate reproduction of the original RGB signal. Component video cables have three connectors on each end.

composite cable

Composite cables are basic analog cables, combining luminance - or brightness - and chrominance - or color information - into one signal. A composite cable supports standard definition, or SD, video only, uses a yellow RCA connector, and is often accompanied by red and white RCA connectors for left and right stereo audio.

contrast ratio

Contrast ratio is the difference in light intensity between a fully lit pixel and a fully dark pixel while the display is active. CRT displays have almost infinite contrast ratios. Examples of LCD contrast ratios are 5,000:1, 100,000:1, and 250,000:1. Two types of contrast ratios exist. The static contrast ratio is the ratio of the brightest and darkest colors that may be produced at the same time. The dynamic contrast ratio is the ratio of the brightest and darkest colors produced over various intervals.

native resolution

Each LCD screen has a native resolution, which is the physical number of pixels that the screen matrix includes. If you set a monitor to display at a lower resolution than its native resolution, it will reduce the size of the visible display or attempt to blend - or interpolate - multiple pixels to produce an image similar to the original, but with a blurred appearance.

HDMI

HDMI connectors were created to support HD DVD and Blu-Ray. The standard cable, Type A, contains 19 pins in a flat, D-shaped shell. Ten of the pins are on the upper inside of the connector, and the remaining pins are on the lower inside. Type B connectors, which have 29 pins, aren't in common use. These connectors are popular because they are small and modular and can carry both high definition - or HD - video and audio streams. miniHDMI is a smaller version of the HDMI connector, used for portable devices such as tablets. These connectors usually have a miniHDMI connector on one end and a standard HDMI connector on the other.

viewing angle

If you want to show someone else what's on your LCD monitor and this person views the monitor from an angle, the image might not be visible or might be distorted. The image might also appear wavy and colors incorrect. The viewing angle, listed in degrees, is the maximum angle from which images on an LCD screen can be viewed without the images appearing distorted. The ideal viewing angle is zero degrees, or centered in front of the LCD monitor. A 90 degree viewing angle covers the area 45 degrees to either side of the center. A 70 degree viewing angle covers the area 35 degrees to either side.

screen size

Is the diagonal measurement, in inches, of the entire picture tube. For CRT monitors, the screen size value can be misleading because the measurement includes areas of the picture tube that are behind the bezel or plastic case that surrounds the viewable area of the screen. For this reason, you might also find another measurement called the viewable area, which measures just the portion of the screen that's visible.

screen size

LCD monitors are measured diagonally, just like CRT monitors. However, unlike the published dimensions of a CRT monitor, those of an LCD monitor refer to the viewable area only. They don't include the areas of the screen the bezel hides.

DVI

LCD screens and digital projectors may use Digital Visual Interface - or DVI - connectors. These are D-sub connectors that can supply both analog and digital information. The number and configuration of pins vary depending on the device to which a connector is designed to connect. A DVI connector has a long horizontal pin on one side of the face, and may have two pins above and below this pin. Next to this long pin are three rows of pins, which differ in number depending on the connector.

LCoS projectors

Liquid crystal on silicon - or LCoS - is a hybrid, or combination, of both LCD and DLP technologies. Typically three LCoS chips are dedicated to the colors blue, red, and green respectively. These chips have liquid crystals that allow light to pass through. This is similar to LCD technology. However, beneath the liquid crystals is a reflective surface. When the light is reflected, the liquid crystal pixels either open or close, which in turn modulates the light to create an image.

refresh rate

Refresh rate - or vertical scan frequency - is the number of times per second that the display is redrawn. The larger the monitor, the higher the refresh rate needs to be. Refresh rates are measured in Hertz. At a refresh rate of 60 Hz, for example, a monitor is refreshed 60 times per second. The image appears more stable at higher refresh rates. The recommended refresh rate for a CRT monitor is at least 85 Hz. Hertz is abbreviated to Hz.

resolution

Resolution refers to the number of pixels - or "dots" - on the display device. It's expressed as the number of pixels per row and column. For example, a monitor with a resolution of 1280 × 1024 has 1280 dots per row and 1024 dots per column. Consider a 15-inch monitor and a 21-inch monitor, both with a maximum resolution of 1280 × 1024. Obviously both monitors have the same number of pixels. However, the 15-inch monitor would have much smaller pixels. This could make the display resolution seem higher, but text may become too small to read.

response time

Response time doesn't apply to CRTs. It is the time it takes in milliseconds for a single pixel to turn on and off. A lower response time will provide better performance. Although subjective, an 8-millisecond response time works well for gaming applications, whereas a 20-millisecond response time is sufficient for tasks such as word processing.

LCD orientation

Some LCD monitors enable you to change the orientation of the display. These types of monitors can be pivoted so that you can view an image in a portrait or landscape orientation. Wide-screen LCD monitors have an aspect ratio of 16:9, compared to the ratio of 4:3 common to CRT monitors, televisions, and standard-screen LCD monitors.

Pixel

The smallest unit of computer displays is known as a ______

VGA

VGA is still a common connector type for displays. This type of connector consists of a blue D-shaped shell - called a D-subminiature or D-sub connector - with 15 pins arranged in three rows of five.

passive matrix

consists of a series of circuits that intersect one another. At each intersection, a single LCD element enables light to pass through. This is an older technology and monitors using it have poorer image quality than those with active matrixes.

OLED

contains an anode and cathode, organic layers - including emissive and conductive layers, and a substrate.

projector

contains red, green, and blue LCDs, and dichroic mirrors for reflecting the different colors of light. It also contains a dichroic combiner cube and a dichroic mirror "wavelength selector".

show desktop on only one monitor

is often used with laptop computers. One monitor, usually an external monitor, will actively display the desktop area, and the other, usually the laptop's built-in screen, isn't used

extend displays

mode increases the desktop area, extending it across all connected display devices.

duplicate displays

mode will duplicate the desktop area on all connected display devices.

LED

operates at 103 to 180 watts of power, whereas an LCD uses 180 to 220 watts. In LED TVs, a light guide plate transports light from source to another point with minimal loss. In LCD TVs, light passes through optical sheets. An LED TV draws much lower current than an LCD TV which uses CCFL bulbs, thus resulting in lower power consumption.