MVA LCD Technology: What You Need to Know

MVA LCD technology—short for multidomain vertical alignment liquid crystal display technology—was developed over 20 years ago by Fujitsu. The technology is known for producing high contrast ratios, crisp and uniform displays over a wide range of viewing angles and an improved dynamic resolution.

This is a welcome change in terms of performance when compared to other, earlier LCD technologies—in particular, the TN and STN.

How is MVA LCD technology able to deliver superior display performance characteristics?

We need to first understand how LCD or liquid crystal display technology works.

How LCD technology works

LCD technology works on the principle of polarization.

What is polarization?

As you might know, light behaves both as a stream of particles and a pattern of electromagnetic waves.

However, when we talk about light in the context of polarization, we specifically refer to its wave nature, recognizing it as a wave pattern of myriad electrical and magnetic vibrations moving in multiple planes of orientation.

Light moves in multiple planes of orientation

Restricting the movement of light in a particular plane of orientation is known as polarization.

Light restricted to vertical plane of orientation is known as vertically polarized light. Light confined to move in the horizontal plane of orientation is known as horizontally polarized light. And so on.

Unpolarized, linearly polarized and circularly polarized light

How does polarization create image in an LCD display?

A typical LCD display unit comprises seven basic components:

  1. Light source
  2. Primary polarizer
  • Liquid crystal (LC) cell
  1. Transistor
  2. Color filter
  3. Secondary polarizer
  • Glass screen

 

When you switch on an LCD display, its light source illuminates. Light, from the light source, travels to the primary polarizer which polarizes the light in a specific plane of orientation, usually horizontal.

In the next stage, the horizontally polarized light passes through a liquid crystal (LC) cell. Depending on the orientation of the molecules present inside the LC cell, the horizontally polarized light either rotates to 90 degrees or passes through the unit as is.

 

Horizontally polarized light being rotated by liquid crystal unit

What is a LC cell and what controls the orientation of its molecules?

Liquid crystal (LC) cell is a type of material that shares properties of both solid and liquid. It has the orderness of solid and fluidity of liquid.

In nematic phase (read: normal substate), LC behaves more like a fluid where the molecules in its crystal lattice can change their orientation on the application of electric field.

In an LCD display, LC cells are arranged is such a way where their molecules assume a twisted configuration by default. Any light that passes through the LC cell in its default configuration is twisted to 90 degrees. On the application of current, the molecules within the LC cell change their orientation and become perpendicular to the primary polarizer. Any light that now passes through the cell is allowed to travel as is without being re-oriented in a different plane of orientation.

 

LCD technology schematics (Image source: Tosaka)

So, as the horizontally polarized light reaches a LC cell, assuming the cell is in its default configuration, the cell rotates the light to 90 degrees and re-orientates it into a vertical plane of orientation. The re-oriented light then passes through the color filter (red, green or blue) and reaches the secondary filter (vertical polarizer). The secondary filter which is also in vertical configuration allows the re-oriented light to pass through it unobstructed. It then hits the screen, producing the respective color.

On the other hand, if the LC cell is switched on, i.e., if it’s under the action of electric field, it allows the horizontally polarized light to pass through it as is without changing its orientation. The horizontally polarized light then passes through the color filter and reaches the secondary filter. However, since the secondary filter is a vertical polarizer, it does not allow the horizontally polarized light to pass through it. This produces a dark/blank image on the screen.

This constant switching of the LC cells, rapidly switches the polarized state of light, creating colorful images on an LCD screen.

The switching of a LC cell is controlled by a transistor. Every LC cell has a separate transistor.

 

Now that you’ve understood how LCD technology works, it’s easier to explain how MVA LCD technology accomplishes superior display performance compared to preceding LCD technologies.

MVA LCD technology produces superior display because to two crucial design changes:

  • First, in MVA LCD systems, the LC cells are arranged in a way that they assume a perpendicular orientation in default state. Because the LC molecules are not twisted, this helps accomplish faster response times and therefore improved dynamic resolution.
  • Secondly, the LC cells on right and left hand side of MVA LCD systems are designed in such a way that they assume opposite orientation to each other. By combining opposite orientations of different LC cells, the technology makes the brightness appear uniform over a wide range of viewing angles, producing superior contrast and crisp displays.

Do you have any other questions about MVA LCD technology? Feel free to reach out; we’ll be happy to assist you.

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