Bend Transition in Pi-cell

Abstract

Films of platinum spluttered in various gases have been examined by the method of electron-diffraction. They often show patterns which indicate that the small crystals are oriented with one face parallel to the surface of the specimen, the crystals being otherwise at random. The width of the rings formed by diffraction shows that in many cases the crystals are very small, of the order of 5 x 10-7 cm. Some films of platinum &oxide showed crystals of the order 2 x IO-' cm. § I. I N T R O D U C T I O N N the course of a research in collaboration with Prof. G. I. Finch and others on the catalytic properties of thin spluttered films of platinum, we have noticed I certain peculiarities in the crystalline condition of some of the films which seemworthy of note. They concern the orientation of the small crystals of which these films are composed, and the size of the crystals.The films were prepared by spluttering in a gas-argon, oxygen, nitrogen or hydrogen-at a pressure of about 0.1 to 0.5 mm. and at voltages varying from about 500 V to 3000 V in different cases. The crystalline nature of the films was investi-* G.P. T., Proc. R. S.128, 649 (1930); 133, I (1931).

P-136 : A Study on the Dynamic Characteristics of Bend Cell for Practical Application of OCB mode LCD

“…Generally the Vcr value is highly depended on both liquid crystal species and align uniformity, that is to say, not only inherent elastic nature of LC's but also a presence of discontinuity in liquid crystal alignment can play an important role in determination of actual Vcr values [3]. However, the initial bend transition favors discontinuity of molecular alignment due to providing a nucleation site to lower the energy barrier in phase transformation [2]. Thus there is a trade-off relation between initial transition and operational stability.…”

“…As generally known, OCB mode of pi-cell is not stable to maintain a bend state at lower voltage than its own critical voltage (Vcr), due to the Gibbs' free energy difference between splay and bend configuration [2]. Practically in general static driving for normally white OCB cell, the maximum operational voltage of black signal will be decided by optical retardation value of the adopted compensator, but the minimum operation voltage for white level must be higher then that of critical voltage, thus some voltage margin for stable operation of actual LCD should be set up with the decision of driving voltage range.…”

“…A bend cell tends to have a splay state via π-twist structure below critical voltage. When the bias of bend state is instantly removed, a metastable bend structure exists for a hundred milliseconds before relaxing to a π-twist structure [2]. If a bias exceeds a certain threshold voltage again before giving back to splay state, the picell immediately returns to bend state within a few milliseconds.…”

11.3: Stereoscopic 3D Display by Fast Response Liquid Crystal Polarization Rotator

“…A very large voltage (>10V) or some special driving scheme must be applied to transform the liquid crystal molecules from the splay state to the bend state. In addition, such transformation is a random process and depends on the nucleation which is difficult to control [5]. Although other fast liquid crystals, such as FLC and Blue Phase LC have also been invented, the use of nematic liquid crystal is still the main stream of the liquid crystal industry.…”

P‐10: A Novel Double Pulse Scan Method for Fast Driving of a π Cell

“…Rubbing directions of the π cell was set at 45° between the parallel polarizers. In order to operate the π cell as a display device, the initial splay state must be changed to a bend state by applying square waves [10][11][12][13]. Figure 2 shows the measured transmittance versus voltage characteristics of the π cell driven by a triangular wave of 5 Hz with a bias voltage of 2.4 V as shown in Fig.…”