Display Technologies

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Display Technologies
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Computer Graphics System
display
Display Processor
CPU
Memory
System Bus
I/O
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Image Quality Parameters

• Resolution
• Color Range
• Blank Between Adjacent Pixels
• Brightness
• Contrast
• Refresh Rate

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CRT
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CRT-Display
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Cathode Ray Tube (CRT)

• Heavy
• High Voltage
• Very Good Resolution

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Liquid Crystal Displays

• Liquid crystal displays use small flat chips
  which change their transparency properties when a
  voltage is applied.
• LCD elements are arranged in an n x m array call
  the LCD matrix
• Level of voltage controls gray levels.
• LCDs elements do not emit light, use backlights
  behind the LCD matrix

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LCD

• Color is obtained by placing filters in front of
  each LCD element
• Usually black space between pixels to separate
  the filters.
• Because of the physical nature of the LCD matrix,
  it is difficult to make the individual LCD pixels
  very small.
• Image quality dependent on viewing angle.

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Passive LCD screens

• Once aligned with the electric field the
  molecules in the LCD will hold their alignment
  for a short time
• Cycle through each element of the LCD matrix
  applying the voltage required for that element.

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Active LCD screens

• Higher contrast and much faster response than
  passive LCD
• Each element contains a small transistor that
  maintains the voltage until the next refresh
  cycle.

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Advantages of LCD

• Light weight
• Flat
• Low power consumption