VA - Vertical Alignment

A type of LCD in which the liquid crystals naturally align vertically to the glass substrates when in their off state. This unique alignment, in combination with the front and rear polarizers, prevents light from passing through, resulting in a deep black background and exceptionally high contrast ratios.

How Does a VA Display Work?

Like Twisted Nematic (TN) displays, VA displays control the passage of light by altering the orientation of LC molecules. However, instead of aligning parallel to the glass (as in TN displays), VA molecules are oriented perpendicular when no voltage is applied.

• Off-State (No Voltage Applied):
  The LC molecules remain vertically aligned, blocking light and producing a dark black background.
• On-State (Voltage Applied):
  The LC molecules tilt to a horizontal position, allowing light to pass through. This makes selected segments or pixels visible, creating bright, high-contrast images.

Advantages of VA Displays

• High Contrast & Deep Blacks: The ability to block light more effectively than TN displays gives VA displays their signature deep black appearance and sharp image quality.
• Wide Viewing Angles: VA technology provides wider viewing angles compared to standard TN panels, though slightly less than IPS panels.
• Vivid Colour Performance: When combined with custom backlighting or optical filters, VA displays can achieve striking color effects, making them a cost-effective alternative to full-color TFT-LCDs.
• Customisable Backlighting: Almost any backlight color can be used, allowing for selective color effects—for example, highlighting warning symbols to capture user attention.
• Colour Options: Striking colour can be added via filters and printing methods (see below)
  

Types of VA Displays

VA LCDs can be either passively driven or actively driven:

• Passive VA Displays: Used in simpler applications with segment-based designs, such as digital meters or domestic applications.
• Active VA Displays (TFT VA): Found in high-resolution colour screens, where thin-film transistors (TFTs) actively drive each pixel, similar to TN and IPS TFT displays.

Colour Filters

Colour filters with colour gradients can be added to the display which delivers much greater visual impact and enhances aesthetics overall when compared to using block colours. They can be applied as a film or printing directly on the polarizer. The intensity of light passing through a selected segment can also be controlled by driver ICs that supports grey scaling, a feature which some UI developers will find useful.