We proposed and demonstrated a new modulation scheme of surface plasmon resonance (SPR) sensor for higher sensitivity. We fabricated novel SPR transducers with wedge membrane structure on the Au thin film (Otto configuration) for gas sensing application. The transducers are composed of SiO<sub>2</sub> / gas flowing layer / Au trilayers, fabricated by wafer bonding of SiO<sub>2</sub> substrate on Au thin film on Si substrate via the ball spacers to define the thickness (t) of the gas flowing layer. There is variation of t within the sample owing to the inhomogeneous bonding force during the adhesion process, leading to variation of t and modulating the SPR within the single transducer. The SPR was measured with attenuated total reflection with a glass prism. We measured SPR for different positions having different t by images detected by a camera with focusing and objective lenses. Asymmetric intensity distributions in the images were fitted with the simulated reflectivity, meaning that the obtained images correspond to the SPR near the cut-off condition in Otto configuration. We observed the shift of the intensity distribution upon the change of the excitation condition through different t. Based on the new modulation scheme, higher sensitivity is expected through analysis of the observed images.
The photopolymer materials of poly(vinyl cinnamate) (PVCi) and polyimides showing homeotropic liquid crystal (LC) alignment have been used to control LC alignment on these films using linearly-polarized (LP)- UV exposure, and the LC alignment mechanism including pretilt angle generation on the films has been discussed. In the case of PVCi, an important contribution of non-dimerized side chains of PVCi molecules to the LC alignment is pointed out. On the other hand, LC alignment on homeotropically alignment polymer films exposed to LP-UV light is shown to be determined through the interaction of LC with alkyl branches attached to the polymer. It is also shown that the photo-alignment method using these photopolymer materials are very promising technique for the fabrication of some attractive LCD modes such as in-plane switching and vertically-aligned display modes, and an example of the application of the photo-alignment method to the fabrication of in-plane switching device is presented.
TN-LCDs having multidomain subpixels have been fabricated using photoalignment. These TN-LCDs exhibit a homogeneous and wide viewing angle. This paper places an emphasis on four domain TN-LCD called super multidomain (SMD). The SMD- TN-LCD exhibits the maximum performance among other multidomain TN-LCDs which is shown in terms of computer simulation and experimental measurements done by the author's group. A non-rubbing technique is required for SMD; we also show that photoalignment is useful for fabricating SMD-TN-LCD. Some performance of an SMD-TN-LCD are demonstrated.
All kinds of LCDs are generally consisted of planar liquid crystal media, which are sandwiched between glass or plastic sheets. In this paper, the LC molecular conformations and their surface alignments in LCDs are systematically introduced, and the methods of LC surface alignment and their mechanisms are discussed. Furthermore the relationship between the EO performance of LCDs, such as TN, STN, Ch-N phase change, FLC, and PD-LCDs and the surface LC alignment is discussed.