Vertical Alignment (VATN Displays) vs. Negative Mode Character LCD Display Module

Published on Wednesday, 09 May 2012 13:30

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VATN Displays – A new LCD Display Technology

A VATN LCD display (Vertically Aligned Twisted Nematic) is one of the newer LCD technologies. We recommend that original equipment manufacturers (OEM) of industrial LCD displays take a serious look at the advantages of this type of display. Specifically, this new display technology has cutting-edge features, which are advantageous to the industrial display industry.  VATN technology offers industrial LCD Displays a wider viewing angle. Monochrome LCD displays have been one of the most popular types of display modules on the market for the last several years. These displays are available in two popular options. Positive mode (dark letters on a light colored background) and negative mode (light colored letters on a darker background). The photo to the left shows a positive mode, STN yellow green with LED backlight.  Compare this to the photo below.

Positive mode is still more popular than negative mode, but negative mode is gaining ground and with the release of a new type of fluid technology called VATN display, we believe that negative mode will become even more popular.

The photo below show a negative mode, FSTN blue background with white LED backlight.      

Advantages of VATN LCD Displays

Some of the advantages of a VATN Display compared to older monochrome LCD modules include:

• Sharper contrast than FSTN (Film Compensated STN)
• Wider viewing angle of 70 degrees in both the X and Y direction (right/left/up/down)
• No hot spots.

How does VATN displays differ from TN, STN & FSTN?

VATN display technology takes a completely different approach than older TN, STN and FSTN technologies. Below is a diagram that displays the differences between a VATN versus a TN LCD module.   As can be seen above, TN allows between 5% to 10% leakage of the light to escape. This reduces the contrast/sharpness of the characters. Also, the oval shape molecules of the VATN are vertical whereas the molecules of the TN are somewhere between horizontal and vertical, but never fully vertical. This allows the VATN display to stay sharp over a wider viewing area.

VATN displays are known by other industries names:

VATN display technology is known by the following names. BTN (Black background Twisted Nematic), vertical alignment displays, Jet black displays and is very similar to EBT (Excellent black Technology). EBT display technology is not the same as VATN, but very similar. We have found the advantages of VATN over EBT include a wider viewing angle and the ability to use this technology in character displays.

VATN displays eliminate hot and cold spots from LED backlights.

One of the greatest advantages of VATN is the elimination of hot and cold spots. Below is a photo of a negative mode display showing hot spots.

Display modules use a polarizer to help spread out the light and make it more even. This does not always work with a blue or white LED backlights. Many times you are left with a hot spot. This can be an issue since they will make the display look produce polka dots. VATN removes hot spots by taking a totally different approach. Below is a photo of a VATN character display. The characters are very bright and there are no hot spots.

Is there such a thing as a VATN graphics displays?

No, at this time the duty cycle of VATN is 1/8 versus 1/16 duty cycle. This means that the LCD will require more controller drivers to keep refreshing the segments. We do expect VATN graphic displays to be available in the future, but they are not in production at this time.