LCD Monitors

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					LCD Monitors

IS 311 Group Presentation
        Topics to be covered

• Beatrice - CRT & LCD Monitor History
• Sici - LCDs Advantages & Disadvantages
• Gil - Current LCDs
• Jerry - Future Trends
• Julio - Buyer’s Guide
CRT & LCD Monitor History

  How it all started
           Monitor Overview
• The most-used output device on a computer.
• Most desktop displays use a cathode ray tube
• Laptops use liquid crystal display (LCD), light-
  emitting diode (LED), and gas plasma or other
  image projection technology.
• Monitors using LCD technologies are beginning to
  replace CRT.
                 LCD History

• Liquid crystals were first discovered in 1888 by
  Austrian botanist Friedrich Reinitzer.
• Melt cholesterol-like substance.
• When cooled, the liquid turned blue before finally
• RCA made the first experimental LCD in (1968).
• Manufacturers have been developing creative
  variations and improvements since on LCDs.
      What is Being Used Today?

•    The most popular display today remains CRT.
•    It has been available for more than 70 years.
•    CRTs:
    1. Vivid colors and detailed images and text.
    2. Cost less than LCD monitors.
    3. Continue to evolve.
           LCD Market Trend

• Market for flat screen LCDs grew rapidly during
  the „90s.
• Huge success of the laptop computer.
• It has still been slow in matching the market share
  of the CRT.
• Color LCDs hit the market in the early „90s.
• Has only now become popular enough for vendors
  to mass-produce.
           From CRT to LCD
  – Bulky, heavy, use vacuum tube
  – Using technology that was
    developed in the 19th century.
  – First LCD laptop monitors were
    very small due to manufacturing
  – Light, sleek, energy-efficient,
    have sharp picture.
                How Monitors Work
• Most use a cathode-ray tube as a
  display device.
• CRT: Glass tube that is narrow at
  one end and opens to a flat screen
  at the other end.
• Narrow end contains electron
   – Single gun for monochrome and
     three guns for color.
   – Display screen is covered with tiny
     phosphor dots that emit light when
     struck by the electron gun.
          Monitor Classifications

• Monochrome: Display two colors, one for the
  background and one for the foreground.

• Gray-Scale: A special type of monochrome monitor
  capable of displaying different shades of gray.

• Color: Can display anywhere from 16 to over 1 million
  different colors. Sometimes called RGB monitors.
    Monitor Quality and Resolution
•   Manufacturers describe quality by dot pitch.
•   Smaller dot pitches mean pixels are closely spaced
    which will yield a sharper image.
•   Most monitors have dot pitches that range from
    0.22mm to 0.39mm.
•   Indicates how densely packed the pixels are.
•   Most modern monitors can display 1024x768 pixels.
•   High end models can display 1280x1024.
              LCD Technology

• Used for displays in notebooks, small computers,
  pagers, phones and other instruments.
• Uses a combination of fluorescent-based backlight,
  color filters, transistors, and liquid crystal to create
  and illuminate images.
• Until recently, was only used on notebook computers
  and other portable devices.
• In 1997, manufactures began to offer full size LCD
  monitors as alternatives to CRT monitors.
              IBM Advances in
             Display Technology

• In 1981, IBM introduced the Color Graphics Adapter
  (CGA) display, able to display 4 colors and max
  resolution of 320x200.

• In 1984, Enhanced Graphics Adapter (EGA) display,
  able to display 16 colors and resolution of 640x350.
       IBM Advances in Display
         Technology (cont.)

• In 1987, Video Graphics Array (VGA) display.
   – Most computers today support the VGA standard.

• In 1990, Extended Graphics Array (XGA) display,
  capable of resolutions 800x600 in true color ( 16.8
  million colors) and 1024x768 in 65,536 colors.

             Apple II
 • Released in 1977
 • First true “personal computer”
 • Based on the Apple I design
   with some additions
    – Plastic case
    – Able to display color graphics
 • Able to display 6 colors at
   280x192 resolution.
Apple II Control Panel
                Pre-IBM (cont.)
• Developed in late 1970s
  by Radio Shack.
• First product in store
  history to fetch more than
• Monitor was basically an
  RCA TV with the tuner
• Became a direct
  competitor to the Apple
              Heath Desktop

• One of the first
  computers designed as
  complete desktop
• Included monitor,
  floppy disks and
• Was eventually bought
  by Zenith.
              IBM PC-1981

• IBM‟s 5150 model
  introduced in 1981.
• The PC featured a 5-
  MHz Intel processor,
  18K of memory and
  an optional color
• Starting price: $1,565
Windows Screen Shots Throughout Time:

                     Windows 3.1
Windows Screen Shots Throughout Time:

    Windows 98

                     Windows 2K
Windows Screen Shots Throughout Time:

             Windows XP
          Advantages of LCDs
• Physical Size
   – Compact and Lightweight
   – Space saving
   – Can be mounted on a wall or panel
          Advantages of LCDs
• Display Size
  – Available at comparable in screen size as traditional
  – Shown on the next slide, a 12.1" LCD display (left) has
    only a slightly smaller viewing area than a typical 14"
    CRT monitor. Newer, larger LCD monitors are also
    appearing that have 15", 17", and even larger screen
    sizes that are comparable to the largest CRT monitors.
    (One thing to note is that LCD monitors are typically
    sized by their actual viewable diagonal measurement,
    but CRTs typically are not.)
Advantages of LCDs
          Advantages of LCDs
• Power Consumption and Radiation Emission
  – Consume less energy and more durable
     • A typical CRT losses approximately 50% of its brightness
       after 10,000 hours. An LCD bulb will maintain its brightness
       anywhere from 25,000 to 50,000 hours.
     • LCD consumes fewer watts than a CRT. LCD will use an
       average 30 watts compared to 120 watts for the CRT.
     • Can reduce electric bill by 40-85%.
     • Uses a combination of fluorescent-based backlight, color
       filters, transistors, and liquid crystal to create and illuminate
       images. It blocks light rather emit light
          Advantages of LCDs
• Power Consumption and Radiation Emission
  – Doest not emit Radiation
  – Not subject to Electromagnetic Interference
            Advantages of LCDs

• Viewing
  – Cause less eyestrain
  – Does not flicker or glare

 (Source: Dailey News – June 2, 2002,,,
          Advantages of CRT

• Color
  – Most are capable of displaying unlimited
• Resolution
  – Multiple video Resolutions.
          Advantages of CRT

• Response Time
  – Faster response time. Critical to people who
    watch videos or play games on their PC‟s.
  – The fastest LCD‟s offer a response time of
    about 25 milliseconds as apposed to CRT‟s
    that have a response time of about 13
         Advantages of CRT
• Viewing Angle
  – Look @ a very wide angle

      Disadvantages of LCDs
• Resolution
     • Displays Native Resolutions (Resolution that it
       displays best)
• Viewing Angle
     • Smaller, needed to be viewed more directly from
       the front.
     • From the side the images on an LCD screen can
       seem to disappear, or invert colors.
     • Newer displays that are coming out have a wider
       viewing angle so this is not as much of an issue as it
       has been in the past.
      Disadvantages of LCDs

• Price
  – Upfront cost it is more costly but long-term
    cost but will conserve energy in the long run.
  – The energy savings may not be much for an
    individual use, but for a corporate office where
    50 displays or more are in use, the energy
    savings might be more of an issue.
       Disadvantages of LCDs

• Installation
  – Need a plug interface to connect to the
  – Some require a special digital plug-interface in
    order to work .
  – Problem: is that this plug is not available on
    most computers, so another video card or
    adapter must be purchased to plug these LCD
    monitors into the computer.
       Disadvantages of LCDs

• Response Time
  – It is much slower. The delay can cause a
    ghosting effect on images it displays.

       Disadvantages of CRTs

• Physical size
  – Takes more desktop space.

       Disadvantages of CRTs
• Power Consumption and Radiation Emission
  – Consumes more energy
  – Emits harmful radiation. The metal shield behind the
    glass of your monitor protects your body from a flood
    of radiation.
  – It holds a dangerous electrical charge even after turned
    off and can last up to several years and be hazardous
    and even deadly to anyone who opens a CRT monitor
  – Know to cause fires due to electrical malfunctions and
    excessive heat if the ventilation holes are accidentally
    covered up.

Current Technology and Trends
            Business Aspect

1. Reasons for a sensitive market:
    I. Price sensitive demand – As price drops
       slightly sales go up sharply.
   II. Long time for production facilities to
            Recent History

• 1999 – Very high demand for LCD
• 2000 – Crash of computer market causes
• Prices are slashed.
Average 17” LCD Monitor Street price

     Quarter             Average Price

               1Q 2001                   $1,148

               2Q 2001                   $1,003

               3Q 2001                   $887

               4Q 2001                   $781

               1Q 2002                   $773

               2Q 2002                   $757

               3Q 2002                   $735

               4Q 2002                   $676
          Technology Aspect

• 1. Display addressing.

• 2. Analog VS digital signal handling.

• 3. Display Uniformity and Viewing Angle .
Active VS. Passive Display

Active Display   Passive Display
TFT (Thin Film Transistor)
   Analog VS Digital signal handling

• On most graphic card signal goes through
  DAC (digital to analog converter) to
  convert to Analog signal.
• LCD must convert the signal back to digital
  to determine which pixel to light.
• If conversion has error the result is "pixel
  jitter", in which the image seems to
  shimmer or move.
     Improved Signal Handling

• 1. DVI (digital video interface) standard
     was adopted.
• i. DVI handles both analog and digital
       signals with separate connectors
• 2. controlling circuitry became substantially
  better in a very short time.
        Display Uniformity


• Early LCD backlight wasn‟t uniform and
  “hot spots” were created.
• Display manufacturers developed more
  sophisticated diffusing materials.
           Viewing Angles

• Improving Viewing angels can be done by
  changing cell design.
• Three different cell designs.
  1. Vertical alignment (VA).
  2. In-plane switching (IPS).
  3. Multi-domain.
LCD Future Trends
      LCD Future Trends

• Short & Long Term Prices
• 3 Important Ergonomic Features
• LCD Monitor Quality
• New Technologies
        LCD Future Trends

• Lower LCD Prices in the Short Term
  – The Dock Works Strike
  – The Slow Economy
  – More Factories Online
         LCD Future Trends
• Lower Prices in the Long-Term
  – Calculators, CRTs, VCRs and DVD Players
    were all very expensive at first
  – They now sell at lower prices because of the
    laws of supply and demand
  – What do they have in common with LCDs?
  – The are all electronic devices
  – So if the laws of supply and demand continue to
     apply, LCDs will sell for less in the long-term
        LCD Future Trends

• Lower Prices in Long-Term (continued)
  – Example of an LCD going down in price
     • IBMs T220 LCD monitor cost about
       $50,000 when it first came out
     • Oct 2001 – it costs: $22,000
     • Dec 2001 – it costs: $15,999
     • May 2002 – it costs: $8,400 (T221)
           LCD Future Trends

• Three Important Ergonomic Features
  – Large Viewing Angles
     • All LCDs approaching 170° both horizontal & vertical
  – Minimal Reflection and Glare
     • Sharp‟s AGLR screen coating which forms a quarter-
       wavelength filter that cancels reflection rather than
       diffusing it as other do.
  – Thin Bezels
     • When working with multiple monitors, your eyes don‟t
       jump past wide gaps – thus less eye strain
LCD Future Trends
  A workstation where all three of
these ergonomic features are useful
        LCD Future Trends

• LCD Monitor Quality
  – Backlights
    • The only thing that can wear out
    • There are more LCDs with 50,000 hour life
  – Zero-Voltage Black
    • lessens impact of non-functioning subpixals
         LCD Future Trends

• New Technologies
  – On-Glass Circuitry unveiled Oct. 22, 2002
     • The new screens use Sharp‟s CGS
       (continuous grain silicon)
     • Microprocessor circuitry applied directly on
       the glass, enabling it to function like a
     • Produces ultra fine resolutions
        LCD Future Trends

• New Technologies (continued)
  – ThinCRTs from Candescent
    • quarter-inch thin form factor: a "thin CRT."
    • Thousands of emitters instead of a single
      large cathode tube
    • Has the best of both CRTs and LCDs
        LCD Future Trends

• ThinCRT from Candescent Technologies
Buyer’s Guide To LCD Monitors

• What to consider when buying a LCD
  –   What applications are going to be used
  –   How much room you have on your desk
  –   How much space you need on a virtual desktop
  –   How much you want to spend
Buyer’s Guide To LCD Monitors

• Key features or things to look for when
  deciding what to buy and how much to
  – Native Resolution
     • LCD uses a matrix of cells to display its
       image, causing it to have a fixed or native
       resolution at which the display looks best
Buyer’s Guide To LCD Monitors

• Viewing angles
  – indicates how you can move to the sides
    or below the center of the screen before
    image is being displayed
  – an angle of 160 degrees is recommended
• Dot Pitch
  – another indicator of image quality
  – the smaller the better; more expensive
Buyer’s Guide To LCD Monitors

• Contrast ratio
  – is the difference in light intensity between the
    brightest white and the darkest black that an
    LCD can produce
  – helps determine how rich the color will be in
    on-screen images
  – recommend a contrast ratio of 300:1 or better
Buyer’s Guide To LCD Monitors

• Digital vs. Analog
  – if you have a graphics card with a digital video-
    out, choose LCD that has digital input
  – image will be clearer because it won‟t have to
    convert from analog to digital and back and
Buyer’s Guide To LCD Monitors
• Prices
  – $200 - $500 range: panel size – 15 inches;
    native resolution – 120/100 to 140/120 degrees;
    contrast ratio – 200:1 to 300:1
  – $500 - $800: panel size – 15 to 17 inches;
    native resolution – 120/100 to 140/120 degrees;
    contrast ratio – 300:1 to 350:1
  – $800 and up: panel size – 17 to 19 inches;
    native resolution – 150/140 to 170/170 degrees;
    contrast ratio – 300:1 to 400:1
Buyer’s Guide To LCD Monitors
• Buying Tips
  – Stick to 15 inch monitors
     • balances screen size and price together well
     • Cheapest
  – Look for a wide viewing angle
     • good for making presentations and working with
     • indicates a higher quality panel with better
       brightness and color effectiveness
     • less tendency to leave trails on screen
Buyer’s Guide To LCD Monitors

• Buying Tips
  – Try before you buy
     • actually looking at your desired monitor is
       always best
     • do not buy online or by mail unless the seller
       has a return policy
Buyer’s Guide To LCD Monitors

• Comparison with CRT buying tips
  – Stick with a 17 inch monitor
     • is big enough and doesn‟t take up too much
     • is cheaper
     • if you work with allot of graphics and image
       editing, go with the $300-$400 19 inch
Buyer’s Guide To LCD Monitors

• Comparison with CRT buying tips
  – Need to consider power cost
     • uses more power than LCD monitors
     • can find low power CRT monitors that have a
       TCO‟99 seal
  – Do not throw away CRT monitors
     • contain large amounts of toxins and lead that destroy
       soil and water
     • Recycle
Buyer’s Guide To LCD Monitors

• Where To Buy
  – Electronic stores (reasonable prices)
    • Fry‟s Electronics, Circuit City, Compaq,
      Best Buy
  – Websites – low prices, but can‟t see what
    you are buying
Buyer’s Guide To LCD Monitors

• Conclusion
  – Prices have been falling over the past two years
     • more affordable for consumers
  – Key features and buying tips mentioned should
    lead consumers in purchasing the right LCD
    monitor for the lowest price