Liquid Crystal Technologies

TN ― Twisted Nematic

A type of liquid crystal whereas the alignment surface and therefore the LC molecules are oriented 90 from each surface of glass. Produces images in two modes: Positive and Negative. Positive Mode provides white background with black segments. Negative Mode provides black background and white segments.

When two polarizing filters are arranged along perpendicular axes, as in the first illustration, light passes through the lead filter and follows the helix arrangement of the liquid crystal molecules. The light is twisted 90 degrees, thus allowing it to pass through the lower filter. When voltage is applied, however, the liquid crystal molecules straighten out of their helix pattern. Light is blocked by lower filter and the screen appears black because of there being no twisting effect.

The multiplex rate is equal to the number of rows that can be displayed simultaneously. For example, a display with a multiplex rate of 16 can display 16 rows of information simultaneously.

ETN ― Enhanced contrast Twisted Nematic

Low cost LCD technology, has a dye in the LCD fluid which increases the contrast in negative mode displays giving improved background appearance. Like TN this suits low duty application 1:1 -1:4 duty, maximum 1;8 duty. Suits wide temperature versions.

ETN segment type displays are ideal solutions for electronic products which requiring high readability such as audio, aire conditioner controller etc.

HTN ― High Twisted Nematic

A type of liquid crystal whereas the alignment surface and therefore the LC molecules are oriented 110̓ from each surface of glass.

Produces images in two modes:

(1)Positive and Negative. Positive Mode provides white background with black segments.

(2)Negative Mode provides black background and white segments.

When two polarizing filters are arranged along perpendicular axes, as in the first illustration, light passes through the lead filter and follows the helix arrangement of the liquid crystal molecules. The light is twisted 110 degrees, thus allowing it to pass through the lower filter. When voltage is applied, however, the liquid crystal molecules straighten out of their helix pattern. Light is blocked by lower filter and the screen appears black because of there being no twisting effect.

STN ― Super-Twisted Nematic

A high information content LCD that uses adjustable interference of two optical modes to achieve a large number of multiplexed lines, higher contrast and higher level of gray scale. It results in the birefringence mode. An improved twisted nematic fluid (twist or greater) which has better contrast and optimum viewing range than standard twisted nematic.

The graph shows a comparison of a voltage versus transmitted light curve of a typical TN and a supertwist nematic (STN) display. (Generally, a greater twist angle equates to higher multiplexibility.) The V90 and V10 points on the graph indicate the voltages that yield 90 percent and 10 percent light transmission, respectively.

As the figure shows, STN displays have a steeper curve than TN displays, which allows higher multiplex levels for STN displays. (STNs were developed primarily to overcome the difficulties encountered in multiplexing TN displays.)

The multiplex rate is equal to the number of rows that can be displayed simultaneously. For example, a display with a multiplex rate of 400 can display 400 rows of information simultaneously.

ESTN ― Enhanced Super Twisted Nematic

ESTN technology displays are enhanced performance STNs. They are low cost replacements for Double STN or Film STN, with nearly the same good performance over wide temperature range. ESTN is used in negative mode displays and can be optimized to the backlight color to increase the contrast ratio. It is an ideal display for the automotive and industrial sectors where wide operating temperature range is crucial.

Features:

1.Transmissive Negative Mode

2.Wide operating temperature range

3.Supper Wide Viewing Angel

4.High brightness

5.High contrast ratio

6.Duty Ratio: 1:8~1:136

FSTN ― Film Compensation Super-Twisted Nematic

LCD with an extra film added to the outside of the cell to compensate the color shift of blue on green to black on white. The film is made of a polymer with double refraction to remove the interference of colors. It results in retardation compensation.

The film (the top layer in the figure) is placed in the display, either under or over the top polarizer. Some film compensation systems use two films, one on the rear that serves as a collimator, and one on the front that serves as a dispersion film to broaden the viewing cone. Film compensation improves the viewing angle, but does not affect switching time. FSTN is all standard STN displays with a polymer film applied to the glass as a compensation layer instead of the second cell as in the case of the DSTN. This simpler and more importantly cost effective method provides the preferred black on white image for this display technology.

ASTN ― Advanced Super-Twisted Nematic

LCD with an extra special TEP (Temperature match Elliptical Polarizer) compensation film added to the outside of the cell. TEP is used as a compensator which can increases contrast and gives the black on white appearance.

Features:

1.Thin and reduced weight.

2.Easy to laminate.

3.Higher brightness through reduced reflections.

4.Temperature compensated driving necessary.

― Improved switching times at low temperature.

5.Cost effective.

BM STN ― Black Mask STN

With inner black masking technology, interelectrode gaps light leakage can be effectively blocked by BM (black ink masking) layer, this BM layer can absorb/block over 99% lightwave so that the contrast can be significantly enhanced.BM STN series character displays are ideal solutions for electronic products which require high readability. Available with different backlight such as RED, WHITE, AMBER, GREEN and BLUE.

BM STN type displays are ideal solutions for Instruments Medical diagnostic applications (Blood Pressure Monitors), Home appliance (coffee machine, audio etc.)