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This study presents and demonstrates an approach for determining the surface tilt angles of parallel-aligned liquid crystal cells. The relationships between the incident angles and the corresponding phase retardations in the splay and the bend configurations are analyzed. The equations for the surface tilt angles are derived accordingly, and their accuracy is discussed. This method does not require knowledge of the cell thickness and is easily applied to assembled pi-cells. OCIS codes: 230.3720, 120.5050.

This investigation elucidates the transient behavior associated with switching between two stable states of a bistable chiral-tilted homeotropic nematic liquid crystal device. Experimental results reveal that the applied pulse voltages and durations not only determine the final states but are interestingly related to the relaxation time. When a suitable pulse voltage is applied, the minimum relaxation time can be obtained by adjusting the pulse duration. Analyzing the hydrodynamic behavior of the liquid crystal directors explicates the switching mechanism and relaxation processes. The principles that underlie the design of the waveforms to have the minimum relaxation time are obtained. [ABSTRACT FROM AUTHOR]

In this paper, we report the thermally induced light leakage in in-plane-switching liquid crystal displays (IPS LCDs) that have a built-in small-angle deviation (<4 deg) between the polarization axis of a polarizer and the rubbing directions for liquid crystal (LC) alignment. We have found that the thermally induced light leakage depends strongly on the phase retardation which is a function of cell gap, wavelength, and birefringence of LCs used in the IPS LC cells. In addition, we have measured the light leakage of vertically aligned LC cells, which is independent of temperature and the deviation angle. A temperature-scanning method is proposed to reduce the light leakage of the IPS LCDs. [ABSTRACT FROM AUTHOR]

A field-induced birefringence method is demonstrated for determining the pre tilt angle of a vertically aligned reflective liquid crystal display. We derive theoretically that the field-induced optical phase retardation is linearly proportional to the square of the applied voltage in the low-voltage regime. The pre tilt angle can be deduced from the slope of this linear relation. The optical phase retardation is measured by a simple optical system and the pre tilt angle can be determined easily. The experimental results agree well with that obtained theoretically. We also describe the applicable range of the applied voltage and the advantage of our method. [ABSTRACT FROM AUTHOR]

Understanding the mechanism of the negative differential resistance (NDR) in transition metal dichalcogenides is essential for fundamental science and the development of electronic devices. Here, the NDR of the current-voltage characteristics was observed based on the glutamine-functionalized WS 2 quantum dots (QDs). The NDR effect can be adjusted by varying the applied voltage range, air pressure, surrounding gases, and relative humidity. A peak-to-valley current ratio as high as 6.3 has been achieved at room temperature. Carrier trapping induced by water molecules was suggested to be responsible for the mechanism of the NDR in the glutamine-functionalized WS 2 QDs. Investigating the NDR of WS 2 QDs may promote the development of memory applications and emerging devices., (© 2021 IOP Publishing Ltd.)