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[Bistable Nematic (BiNem) mode mode]

The BiNem mode was introduced by Nemoptic, it uses two different anchoring conditions on two substrates to achieve the bistability, usually one substrate is a weak planar anchoring and the other one has a strong tilted anchoring. This is also called "surface anchoring breaking". The BiNem mode has two states, which are uniform (U) and twist (T) states. The two states can be interchanged by applying different pulses. As shown in the following figure, to switch from U state to the T state, a pulse with sharp falling edge is required. while from T to U state, a pulse with smooth falling edge is necessary. Both the U and T states are stable even without applied field.



Figure 1. BiNem display working principle (a) pulse with a sharp falling edge; (b) pulse with a smooth falling edge.

In principle, the BiNem only has two states, and hence no gray scales. But it can be realized by driving signal modulation, through controlling the amount of black and white area separated by a border line in one pixel. When the signal changes, the border line moves to change the amount of black and white, hence different gray scales are achieved. Since it is like the curtain moving down on a window, it is also called "curtain effect".

Figure 2. Gray-scale realization in BiNem display by "curtain effect".

The color BiNem display is realized by implementing standard color filters. A 32K color display was demonstrated by Nemoptic*.

(*Picture is from nemoptic.com)

Further Readings and References:

I. Dozov et al, Fast bistable nematic display from coupled surface anchoring breaking , Proceedings of SPIE vol. 3015, 61 (1997).

I. Dozov et al., Fast bistable nematic display using monostable surface switching , Appl. Phys. Lett. 70, 1179 (1997).

D. N. Stoenescu, I. Dozov, and Ph. Martinot-Lagarde, Mol.Cryst. Liq. Cryst. Sci. Technol., Sect. A 351, 427 (2000).

S. Lamarque-Forget, Ph. Martinot-Lagarde, and I. Dozov, Jpn. J. Appl. Phys., Part 2 40 L349 (2001).

S. Joly, K. Antonova, Ph. Martinot-Lagarde, and  I. Dozov, Phys. Rev. E 70, 050701(R) (2004)



Last update: April, 2006
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