In addition to Kopin's standard displays with twisted nematic (TN) liquid crystal materials, Kopin has developed a patent-pending multi-domain vertical alignment (MVA) technology that offers normally black images (at zero bias voltage) with very high contrast ratio and wide symmetric viewing.

Contrast ratio plotted as a function of viewing angle for the MVA mono display with a custom wide-angle viewing polarizer.

Although traditional MVAs that use protrusion and ITO slit geometry are now widely used in advanced mobile phones and LCD TVs, it is not suitable for microdisplay applications because the required protrusion and ITO slit will make the light transmission very low. Kopin's unique MVA technology has enabled Kopin to introduce monochrome microdisplays with a wide viewing angle and a contrast ratio greater than 300. The normally black LCD with high contrast ratio is the most preferred mode for the military applications, especially for the night vision applications.

More technical information can be found in the article:
A normally black, high contrast, wide symmetrical viewing angle AMLCD for military head mounted displays (HMDs) and other viewer applications