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ICT Lesson, 22 Feb notes

1. Visual Display Unit

  • Visual Display unit (projectors)

    • Very big category

    • Monitors

      • CRT (gone since long)
        • Very durable but is extremely large
      • Plasma (gone since long)
        • very expensive
      • LCD
        • Liquid Crystal Display
        • Newer technology
        • How does it work?
          • A light behind the screen give light
          • The Liquid Crystal change reflection rate when current pass through
          • Different color will then be shown on the screen
      • LED
        • Newer technology
        • Similar to LCD
          • Basically same with LCD except the points on screen can glow without a light in back
      • LCD vs LED
        • Full black: LCD will not be full black (still have a bit light); LED will actually be full black (that's how AMOLED black works)

    • TVs

      • Similar with a monitor (but is NOT a monitor)
      • Can do more stuff (e.g. receive TV signals)

    • TV wall

      • Multiple TV combine to show 1 thing

    • LED Walls

      • Basically big LED display
      • If you walk closely you can see a lot of led light bulb

    • Touchscreens

      • Invented in Hong Kong (TM)

    • New stuff: Contrast Ratio & Refresh Rate

2. Refresh rate

- 60Hz / 120Hz / 144Hz / 160Hz
- The higher the refresh rate, the more images in a second
- The more images in a second, the more times the screen reloads the image
- If camera refresh rate > screen refresh rate, you may be able to see flicker in image.