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LCD,Monitors,Graph plotters,VR headsets,printers(all),microfilm/fiche

Posted on 1997-11-20
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Last Modified: 2007-02-13
I am doing a computing project on output units and need a lot of detailed information on:-
 1)What they are used for
 2)How they work in detail
 3)Their advantages and disadvantages

The things I require information on are:-

-Monitors and VDU's
-LCD display screens
-Information onall printers(bubble,inkjet,laser(+colour),thermal, and dot matrix
-Information on graph plotters (flatbed and drum)
- VR HEADSETS AND THE GLOVES THEY USE
- Microfilms and microfiches

Thanks a lot, & whoever answers most questions will get most
points.
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Question by:Pundit
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delphinus earned 170 total points
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Monitors and VDUs:
  The standard CRT (Cathode Ray Tube) display uses
  a large vacuum tube in which it projects electrons
  against a phosphorescent screen.  As the electrons
  strike the screen, the phosphors emit light, resulting
  in the displayed picture.  The electron beam is
  focussed and scanned using magnetic fields.

  The advantages of this technology are high speed and
  high contrast.  It's a very well-developed technology
  due to the long-standing research of the television
  industry.

  The disadvantages are the units' bulk and power
  consumption.  CRTs are simple too large for portable
  computing applications.


LCD display screens:
  Liquid Crystal Displays are used for any application
  which requires a small flat-panel display.  They are
  most commonly seen in digital watches and calculators.

  LCDs work on the principle of reflected and transmitted
  light.  Small crystals suspended in the display change
  their reflectivity and transmissivity depending on the
  current being passed through them.

  The main advantage of LCDs is that they are small and
  light.  They are the dominant display technology for
  portable computing applications.

  The disadvantages are numerous.  LCDs are slow, thus
  making them undesirable for motion picture applications.
  They are also very expensive to manufacture, since for
  color LCDs, the crystals have to be microfabricated
  precisely with very high quality.


Printers:
  Dot Matrix:
    These were the dominant printer of the past, and are
    still used when printing forms which require carbon
    copy sheets to be used.

    They are based on a simple impact principle.  Small
    pins arranged in a rectangular matrix strike patterns
    on a ribbon sitting on top of the paper.  This produces
    the characters on the page.

    The only main advantage today is cost.  These printers
    are very inexpensive, and cost-effective.  However,
    even so, they have fallen into disuse because of poor
    print quality, and loud noise characteristics.

  Thermal:
    Thermal printers were widely used before the advent of
    color inkjets.  These are similar to dot matrix, except
    that the matrix is heated instead of struck.  The
    dot pins produce heat in the pattern required for
    the particular character, and merely brush against
    specially-coated thermal paper.  The paper reacts
    in heat, and produces the image desired.

    There isn't much in the way of an advantage for this
    technology anymore.  The main disadvantage is that
    it requires special paper, which can be expensive.

  Laser:
    The laser printer is based on a technology very similar
    to that of the photocopier.  A photosensitive rotating
    drum inside of the printer is scanned, using a laser,
    with the reverse of the pattern desired.  Using laser
    focussing techniques, the resolution can be very very
    sharp.  Wherever the laser strikes the drum, it is
    magnetized.  The drum then rotates through a ferro-
    magnetic dust-like toner.  The toner is picked up
    by the magnetic portion of the drum.  The drum is
    rotated over the paper, and the toner is then fused
    to the paper using a heat roller.  Color laser works
    in a similar fashion, but with 4 different colors of
    toner (Black, Cyan, Yellow, Magenta, typically).

    Laser printers have become the dominant printing
    modality in the corporate world due to their speed,
    resolution, and low noise level.  The only real
    disadvantages are their bulk, and the high cost of
    color.  However, these two disadvantages are rapidly
    diminishing.

  Inkjet:
    This technology is very similar to dot matrix
    technology.  Instead of striking pins, however, each
    point in the matrix is actually a miniature ink
    spray.  The ink sprays spurt out ink in small,
    precisely-measured quantities as the head moves
    over the page.  Because of the small size of the
    jet holes, the quality is very good.

    The advantages of inkjet are low cost, and inexpensive
    color printing.  Color is simple, in that it merely
    requires more than one pass over the paper with
    different colored inks.

    Disadvantages include running of the ink, and slow
    printing time.  Inkjets used to require specially
    absorbant paper, but with better ink formulations,
    they can print on any normal paper.

  Graph plotters:
    Plotters were very popular before the onset of
    inexpensive laser printing.  Now, they are mostly
    restricted to making very large diagrams.

    Plotters work on the principle of actually drawing
    the image using a pen, or array of pens.  A plotter
    essentially works just like a human drawing with
    a pen on a piece of paper.  Thus, it is easy to
    make a plotter arbitrarily large.

    The only difference bewteen a flatbed and a drum
    plotter is the motion mechanism.  Instead of moving
    across and down a flat piece of paper, the drum
    plotter moves across and rotates the drum.  The
    same effect is achieved.

    The main advantage of a plotter is its arbitrary size.
    It can be made essentially as large as desired.
    Disadvantages include slow print speed for text, and
    generally poor quality as the pens degrade over time.


VR Headsets and Gloves:
  VR Headsets are merely small LCD screens placed close
  to the eyes of the wearer.  They attempt to immerse
  the wearer into the world being presented.

  VR Headsets have the advantage of provide a wide depth
  of view in a compact package, but have the disadvantage
  of being only able to be viewed by one person at a time.

  VR Gloves have transducers on them which allow the
  device to determine its position and orientation.  This
  information can be used as inputs into a computer.


Microfilm and Microfiche:
  These are just incarnations of photographic film, but
  with extremely high resolution.  Photographs of printed
  material are taken with a high-resolution camera and
  film.  The film is then developed and stored.  Hundreds
  of pages can be stored in a small area.

  Microfilm is a roll of such film in a cartridge or in
  spool form.  A machine allows the viewed to roll the
  film in either direction to search for relevant items.

  Microfiche is a variant of this concept.  Flat slides,
  about half the size of a piece of paper, are viewed
  using a slide viewing machine.  This allows essentially
  random access, since the viewer is indexing across a
  flat surface.  Hundreds of pages can be stored on any
  one such slide.

  Microfilm and microfiche achieve very high storage
  density per unit volume, but will most likely soon become
  out of vogue with the development of larger and more
  inexpensive computer memories.  CDROM has already begun
  to displace microfilm and microfiche as a form of
  printed material storage.


I hope this answers your questions.
Good luck on your research project.

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