DHF mode

Therefore at relatively low field a fast and reversible switching could be obtained in the DHF mode. Note that the optics of the DHF effect is almost the same as that of... 

Section 2 covers the DHF mode with a helical structure. The bookshelf structure, the Cl-uniform (CIU) orientation, and the C2-uniform (C2U) orientation are described in Sections 3, 4, and 5, respectively. Section 6 covers the stability of the molecular orientations in FLC devices exposed to shock. Weakness in this respect is one of the intrinsic problems of FLC displays. The layer rotation behaviour, an intrinsic behaviour of FLC displays, is described in Section 7. 

Among these modes, (2) DHF mode, (3) twisted FLC mode, (4) monostable FLC mode, (8) CDR mode, (5) the application of Parallel Stripe Texture and (9) the application of the frustoelectric liquid crystalline phase are reviewed below. 

In the case of a helical pitch shorter than the wavelength of visible light, colouration due to selective reflection from the helical structure disappears and the rotation of the optical axis by deformation of the helical structure can be used for optical switching. This mode is called the Deformed-Helix Ferroelectric (DHF) liquid crystal mode. The DHF mode can realize stable continuous grey scale. Moreover, the viewing angle dependence of the contrast is small even in... 

The most serious problem with respect to the DHF mode is that the helical structure is unwound and the alignment is deteriorated by applying an electric voltage larger than the saturated voltage. This is different from the cholesteric helical structure which is restored by cutting off the electric field. This phenomenon restricts applications, and, furthermore, is a critical problem from the viewpoint of product quality assurance. 

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