Computer Monitors

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Computer Monitors

• B. Konkoth

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Types of monitors

• CRT
• Cathode Ray Tube
• LCD
• Liquid Crystal Display

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CRT

• The filaments at the back of the cathode tube
  shoot a beam of electrons to the screen at the
  front of the tube
• This screen is coated with phosphor that glows
  when struck by the electron beam.

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LCD

• An LCD panel produces an image using a liquid
  crystal material made of large, easily polarized
  molecules

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2 types of LCD panels

• Active matrix
• Most common
• Contains cells of liquid crystal, a matrix of
  thin-film transistors (TFT)
• provides a much brighter, sharper display

• Passive matrix
• Dual-scan display
• Has a row of transistors running on the top of
  the screen as well as the left of the screen

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Features of a monitor
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Video cards

• Interface between the monitor and the computer.
• Also called graphic adapters, video boards,
  graphics cards, or display cards.
• Sometimes the video controller with a video port
  is integrated into the motherboard.

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Video card
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Methods of data transfer

• RGB video port
• standard method of passing three separate signals
  for red, green, and blue which most video cards
  and CRT monitors use.
• uses a regular 15-pin Super VGA port

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Methods of data transfer

• DVI port - Digital Visual Interface port
• digital interface standard used by digital
  monitor such as a digital flat panel monitor, and
  digital TVs (HDTV).
• for a video card that only has a DVI port, you
  can purchase a VGA converter so you can connect a
  standard VGA cable to use a regular analog
  monitor.

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Methods of data transfer

• S-Video Super Video
• this method sends two signals over the cable, one
  for color and the other for brightness, and is
  used by some high end TVs and video equipments.
• it uses a 4-pin round port

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Methods of data transfer

• Composite video
• using this method, the red, green, and blue (RGB)
  are mixed together in the same signal.
• this is the method used by television and can be
  used by a video card that is designed to send
  output to a TV

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Flat Screen Monitors

• LCD - Plasma
• Picture Quality
• Normal computing, both LCD and plasma screens
  will provide sharp and clear display
• Watching Blu-Ray movies or playing
  high-definition games, Plasma screens have less
  picture lag and sharper color resolution than LCD
  displays.

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LCD - Plasma

• Power Usage
• LCDs use considerably less power than plasma
  displays, which use self-lighting pixels
• Screen Burn-In
• Plasma screens are more likely to experience
  screen burn-in (the screen becomes permanently
  discolored where the unchanging image was)

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LCD - Plasma

• Pixel Levels
• LCD screens generally have more pixels per square
  inch than plasma
• makes them ideal if you are working with complex
  spreadsheet programs or editing software
• Size
• Plasma monitors are usually ahead of the curve
  regarding their maximum size
• the biggest monitors are plasma

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LCD - Plasma

• Lifespan
• LCD monitors tend to be rated for 60,000-plus
  hours
• Plasma monitors range from 20,000 to 30,000 hours
  
• Price
• Comparable pricing

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Analog DTV - HDTV

• Analog
• CRT sets
• signal is made of continually varying radio waves
  that the TV translates into a picture and sound
• DTV
• United States broadcasting is currently changed
  to digital television (DTV )
• The picture, even when displayed on a small TV,
  is better quality

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HDTV

• 18 Digital TV standards
• HDTV is the highest of all the DTV standards
• Aspect ratio, Resolution, Frame rate determines
  the differences

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• Aspect ratio - Standard television has a 43
  aspect ratio -- it is four units wide by three
  units high. HDTV has a 169 aspect ratio, more
  like a movie screen.
• Resolution - The lowest standard resolution
  (SDTV) will be about the same as analog TV and
  will go up to 704 x 480 pixels. The highest HDTV
  resolution is 1920 x 1080 pixels. HDTV can
  display about ten times as many pixels as an
  analog TV set.
• Frame rate - A set's frame rate describes how
  many times it creates a complete picture on the
  screen every second. DTV frame rates usually end
  in "i" or "p" to denote whether they are
  interlaced or progressive. DTV frame rates range
  from 24p (24 frames per second, progressive) to
  60p (60 frames per second, progressive).