What Does the Term a-si TFT/PVA Mean?

The term, a-si TFT/PVA, describes what the liquid crystal cells (pixels) in an LCD screen are made of and how the liquid crystal cells in the screen are controlled and configured.

Description of Each Term
  • a-si - amorphous silicon. The kind of silicon used in the LCD screen.
  • TFT - Thin Field Transistors. The kind of transistors used to control the liquid crystal cells in the LCD screen.
  • PVA - Patterned Vertical Alignment. The orientation of the liquid crystal particles in the LCD screen.

Here is another term you might see:

  • TN - Twisted Nematic. A kind of liquid crystal used in LCD monitors that is naturally twisted. TNs have two interesting properties:
    • When you apply an electric current to a TN, it untwists, with the amount of untwisting dependent upon the voltage of the current.
    • The amount of light that can pass through a TN depends upon how twisted it is.

Because you can cause a TN to untwist by applying an electric current to it and control the amount it untwists by varying the voltage of the current, you can control the amount of light that passes through a TN by changing the voltage of a current you apply to the TN.

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