Saturday, August 12, 2006

Flat Panel TV Display Technology

TV Resolution Standards:

The CRT or Cathode Ray Tube Television Technology that all of us know about, has been commercially available since the 1950's.
It is currently refereed to as SDTV for Standard Definition Television. This technology allows up to 480 interlaced lines, while 240 line are visible to the viewer on each pass.

The much-talked about HDTV or High Definition Television comes in two flavors. Progressive Scan like your computers monitor and interlace like SDTV. HDTV allow for a high number of lines to be drawn on the screen allowing for images that are extraordinarily sharp with greater color fidelity.

HDTV is available in three flavors:
720p & 1080p – Progressive Scan 720 or 1080 lines are drawn across the screen once.
1080i – Interlace Scanning draws 540 lines on each pass for a total of 1080 lines.
Lastly there is EDTV or Enhanced Definition TV, these displays display at least 480 lines using the progressive scan method (480p) of HDTV, which allows for a sharper image over SDTV since interlacing is not used.

For a more detailed analysis of Television Display technologies you may be interested in:
How Home Theater and HDTV Work
How Home Theater and HDTV Work

Turn Your PC into Super TV with Instant access to 5000+ TV & radio channels. No recurring charges. For $39.95


Competing Display Technologies:
There are currently three major display technologies that are available in the consumer market when it comes to flat panel televisions.
They are:
LCD Displays (Liquid Crystal Displays)
Plasma Displays (Similar a Neon Display)
DLP Displays (Digital Light Processing Displays)

LCD Displays the oldest and most widely used of the technologies (it can be found on desktop monitors, notebooks, handheld displays, digital cameras, watches, portable games consoles...) is comprised of a system of components, the liquid crystal being chief among them.
LCD Display technology is available in passive and active version, the active version, which we are discussing here, allows for the full control of every pixel that comprises the display.
LCD Display utilizes Thin Film Transistors (TFT) to create an Active Matrix Display Area that controls the images you see on the screen.
An LCD Display is made up of a
Bottom Polarizer
Bottom Piece of Glass
Active Matrix of Thin Film Transistors
Liquid Crystal Compound
An Electrode
A Color Filter
Top Glass
Top Polarizer

Plasma Display Technology is considered an emissive display technology where by light is created by the excitation of phosphors by an inert mixture of noble gases which when electrically ionized create a plasma discharge.
At its most basic a Plasma Display is a sandwich configuration of:
Noble gases

DLP (Digital Light Processing) Technology is the newest of the television Display to hit the market and was originally developed by Texas Instruments.
DLP is a light projection technology that uses a matrix of microscopic mirrors, a color wheel, and a light source.

The microscopic mirrors allow for the blocking or reflecting of light that passes through a color wheel producing the image one sees.
There are currently two DLP Systems in use, those using a single chip DLP projector and those using a three chip project each for the primary Red, Green and Blue colors.
In single Chip DLP projectors the Digital MicroMirror Device is placed between a light source and a color wheel.

The proper color to image synchronization is handled by a complex image display processor so that color and image intensity (brightness or darkness) is displayed correctly.
In Three Chip DLP projectors a prism is used to split the light from the lamp into its primary RGB components, and then each light component is routed to a Digital MicroMirror Device.
After the light is processed it is then recombined and routed to a lens.

Newer DLP Projectors will soon due away with the lamp and color wheel and prism, an instead use LEDs (Light Emitting Diodes) for each of the primary colors (RGB - Red, Green, Blue).

You may also find
Guide to HDTV Systems
Guide to HDTV Systems

an informative read on the history and current development of display technology.

Build Your Own Projection TV

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