Reflective and Transflective liquid crystal displays using a wire grid reflector.

A device structure for single cell gap reflective and transflective liquid crystal displays (TF-LCDs). For an entirely reflective LCD, the imbedded wire-grid polarizer (WGP) serves as a polarization-dependent for the ambient light. For a transflective TF-LCD, the WGP only covers the reflective pixels. The disclosure also includes a method of using single cell gap liquid crystal displays (LCDs) without phase retardation films by providing a single cell gap LCD having reflective pixels and transmissive pixels, covering solely the reflective pixels, with at least one of: a wire grid polarizer and a broadband cholesteric reflector (BCR), reflecting ambient light off the reflective pixels; and passing back light through the transmissive pixels whereby the cell gap LCD obtains high contrast ratios without using phase retardation films

Transflective Liquid Crystal Display with Partial Switching

A high reflection and transmission transflective liquid crystal display (TLCD) that requires only a single cell gap. Instead of reducing the cell gap of the R sub-pixel region, the invention reduces the birefringence change .DELTA.n of reflective pixels (R) so that the total retardation change .DELTA.nd of R is equal to that of the transmissive pixels (T). This is realized by a partial switching of the pixels of approximately 45 degrees which occurs in the reflective pixel (R) region of the single cell gap by applying fringing fields, generated by a discontinuous electrode, to the molecules in the reflective pixel (R) region of the cell gap

Fast Response Liquid Crystal Mode

A novel nematic liquid crystal (LC) mode is based on the Fringing-Field-Switching of Vertically-Aligned liquid crystals. The VA-FFS mode is capable of generating very fast optical modulation without the use of very thin cell gap. IA major feature of this LC mode is that it has unusual fast relaxation time compared with the conventional nematic LC modes that require a thin cell gap. This fast relaxation occurs even at very low applied voltages and the operation is very stable. The fast-response mechanism of this LC mode involves the confinement of liquid crystal molecular switching within self-imposed thin LC layers. The present invention provides a novel approach to overcome the fundamental problem of the long relaxation time of the conventional nematic liquid crystal modes

Curing temperature effects on liquid crystal gels

The curing temperature is found to greatly affect the operating voltage, contrast ratio, hysteresis, and response time of the reversed-mode liquid crystal (LC) gels. For the gels using E48 LC host, the optimal curing temperature is around 40-50degreesC. An LC gel with contrast ratio exceeds 2000:1 (at similar to2degrees collection angle), operating voltage lower than 7 V-rms, and response time of about 20 ms is demonstrated. Potential applications of such LC gels for optical switches, displays, and switchable polarizers are emphasized

Reflective liquid crystal projection displays with low voltage and high contrast using improved bisector effect.

Methods, systems, devices and apparatus of using a reflective liquid crystal device for projection display operating at a reduced driving voltage and having an increased contrast ratio are disclosed. The reflective liquid crystal device comprises a first substrate, a second substrate with reflector means, and a twisted nematic liquid crystal layer between the first substrate and the second substrate. A polarizing beam splitter is placed outside of the reflective liquid crystal device and adjacent to the first substrate. By setting the entrance polarization direction of the polarizing beam splitter along the azimuthal angle of the linearly polarized eigenmode of the reflective liquid crystal device at the designed driving voltage, a perfect dark state is obtained, which leads to a high contrast ratio at the designed low driving voltage

Multi-Film Compensation liquid crystal display with Intial Homogenous Alignment

A liquid crystal display having a positive A-film and a negative A-film between a top polarizer and a bottom polarizer to increase the viewing angle of the liquid crystal display by reducing or eliminating light leakage at voltage-off state when viewed from an oblique angle. Method of increasing the viewing angle of the liquid crystal display by reducing or eliminating light leakage at voltage-off stage when viewed from an oblique angle. The compensation is applicable to use with liquid crystal displays having a liquid crystal layer that is homogenously aligned at off-state when no voltage is applied to the liquid crystal layer, such as IPS and FFS mode liquid crystal displays

Polymer-stabilized blue phase liquid crystals: a tutorial Invited

Blue phase liquid crystals exhibit several attractive features, such as self-assembled three-dimensional cubic structures, optically-isotropic in the voltage-off state, no need for alignment layers, and submillisecond response time. This tutorial gives step-by-step introduction on basic blue-phase materials and properties, monomers and polymerization processes, and key device performance criteria for display and photonics applications

Nanowire grid polarizer for energy efficient and wide-view liquid crystal displays

We report a liquid crystal display (LCD) using a nanowire grid polarizer (NWGP) to replace the bottom sheet linear polarizer (LP). The top LP and bottom NWGP configurations enable backlight recycling for enhancing optical efficiency while keeping a high contrast ratio and wide viewing angle. The electro-optic performance of this device configuration is studied based on the effective-medium theory and 4 x 4 matrix method. Results show that this configuration exhibits a 100: 1 contrast ratio over 75 S viewing cone in a film-compensated multidomain vertical alignment LCD and 10: 1 over 65 S viewing cone in a fringe-field switching LCD without any compensation film. (C) 2008 American Institute of Physics

Tunable electronic lens using a gradient polymer network liquid crystal

Tunable electronic lenses using gradient polymer network liquid crystal (PNLC) cells were demonstrated. By changing the photomask pattern, both positive and negative lenses were fabricated. The advantages of such a PNLC lens are low operation voltage, large aperture size, and simple electrode design. To overcome the polarization dependence, stacking two orthogonal homogeneous PNLC cells is considered

Variable-focus liquid lens by changing aperture

We propose an adaptive liquid-filled lens, which consists of an elastic membrane, a solid plate, and an annular sealing ring; a liquid with a fixed volume stored in lens chamber. The key part is the annular sealing ring which looks like an iris diaphragm. The surfaces of annular sealing ring are sealed with an elastic membrane. The radius of the annular sealing ring is changeable. By tuning the radius of the annular sealing ring, the stored liquid in the lens will be redistributed, thus changing the curvature of the elastic membrane. Therefore, the lens cell causes light to converge or diverge. A liquid lens with a positive variable focus was demonstrated, this kind of lens has the advantages of simple fabrication process, compact structure, easy operation, and low cost