Positive And Negative LCD Screens
LCD Screens are available in two options. Positive mode (dark letters on a light colored background) and negative mode (light colored letters on a darker background).
This is the blog exploring advances in segment display technology and showing
how it remains a real alternative to TFT displays. Previously we explored adding color to segment and dot matrix display.
The typical viewing angel and contrast of today’s segment displays are generally better than those of earlier generations,
giving sharper definitin and clearer legibility whether viewing from a distance or close-up. New vertical-alignment technology enables segment displays with a conventional black background to deliver still more impressive visual performance, by preventing bleed of even small quantities of light from the lit segment into the dark background. The improvements are particularly noticeable edges that give a beautiful, high-quality effect.
This is achieved by making the liquid crystals naturally align vertically to the glass substrates. When no voltage is applied, the liquid
crystals remain perpendicular to the substrate, greatly reducing light bleed-thought between crossed polarizers as observed in TN displays.
When voltage is applied, the liquid crystals shift to a tilted position, allowing light to pass through and create a grey-scale display depending
on the amount of tilt generated by the electric field.
Traditionally, the way to achieve this kind of improvement in performance has been to use a relatively expensive technology such as
DSTN (Double Super Twisted Nematic). Vertical alignment now makes the effect more affordable and more effective, and has a deeper-black
background, a higher contrast ratio, a wider viewing angle, and better image quality at extreme temperature.
Post time: Sep-21-2018