An optical add/drop wavelength switch is controllably changed from a bridge state, in which output is identical to input, e.g. a Wavelength Division Multiplexed (WDM) input, and an add/drop state, In which a signal input to an add port is substituted for a particular wavelength subrange of the WDM input, other wavelengths of the WDM input being unchanged. In one embodiment, the wavelength subrange of the WDM signal is given a polarization different from other wavelengths of the WDM, such as by using a stacked waveplate or other optical filter or polarization discriminator. The differently-polarized wavelengths can the be spatially separated, e.g. by a birefringent element or a polarization beam splitter, preferably In a bit-controlled fashion, such as by using a liquid crystal or other polarization controller. Polarization controllers and discriminators can be used similarly to selectably align or combine the add signal with the portion of the WDM signal outside the subrange. The add/drop wavelength switch can be used, e.g. In an optical token ring network and/or to make-up an optical crossbar for exchanging any arbitrarily designatable channels, e.g. among a plurality of multi-channel optical fibers.

Optical add/drop wavelength switch

This report is a supplement to the literature review, FHWA-RD-95-153. The purpose of the review was twofold: first, to conduct a literature review of human factors-applicable articles associated with Advanced Traveler Information Systems (ATIS) and ATIS-related commercial vehicle operations (CVO) systems and to extract existing human factors guidelines for the development of future ATIS devices, and second, to identify areas in which further research was needed in order to establish guidelines. An extensive search was conducted of the ITS human factors research available in the open literature. Included in the review are: relevant technical ATIS reports; literature from automobile and CVO manufacturers, after-market system development companies, ITS university researchers, and government agencies; and documents from Europe and Japan. The main body of this supplement report contains a brief summary of over 250 articles found for the literature review. The articles appear alphabetically. Applicability to guideline development and usefulness to future project tasks is indicated for each article. There are two appendices. The first contains each citation, the associated keywords and the page number from the main report. The second is a keyword index.

Development of human factors guidelines for advanced traveler information systems and commercial vehicle operations: literature review

In liquid crystal display cells comprising a liquid crystal (7) disposed between two substrate plates (1,2) provided with drive electrodes (3,4), the orientation layer (5,6) on the inner sides of the plates where the electrodes are disposed comprises an oriented photopolymer layer. This layer is formed by irradiating photopolymer layer. This layer is formed by irradiating photoreactive material with linear polarized light.

Liquid crystal display cells

A protective automatic darkening filter construction 10 includes two low twist liquid crystal cells 26, 30 interspersed between a series of offset polarizers 24, 28, 32. The resulting construction provides improved homogeneity in the dark state as viewed by the user over a large viewing angle. By reducing variations in shade, visibility through the filter may be improved.

Automatic darkening filter with offset polarizers

A liquid crystal display device comprising: (a) a liquid crystal layer arranged between substrates each having an electrode; (b) a pair of polarizers arranged so as to sandwich the liquid crystal layer; (c) a birefringent medium arranged between the liquid crystal layer and at least one of the polarizers, when a voltage is applied so that liquid crystal molecules at boundary regions facing said substrates have different tilt angles from other molecules, retardation in said birefringent medium being equal or close to remaining retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said remaining retardation; and (d) control means for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.

Liquid crystal display device with residual retardation compensated for in liquid crystal layer

A liquid crystal display device of negative display type, which comprises a liquid crystal cell comprising a nematic liquid crystal layer sandwiched between substrates provided with electrodes, a light shielding layer covering other than the area corresponding to a display pattern, a pair of polarizing films provided on both sides of the liquid crystal cell with their polarization axes arranged to permit light from a no voltage-applied portion to pass therethrough, said liquid crystal cell being adapted to apply a voltage sufficient to energize the nematic liquid crystal to the electrodes at a display pattern area other than a desired display pattern, wherein a twist angle of liquid crystal layer is in a range of 50 DEG -80 DEG 

Liquid crystal display device with a 50 DEG -80 DEG twist angle

A liquid crystal display device of negative display type, which comprises a liquid crystal cell comprising a nematic liquid crystal layer sandwiched between substrates provided with electrodes, a light shielding layer covering other than the area corresponding to a display pattern, a pair of polarizing films provided on both sides of the liquid crystal cell with their polarization axes arranged to permit light from a no voltage-applied portion to pass therethrough, said liquid crystal cell being adapted to apply a voltage sufficient to energize the nematic liquid crystal to the electrodes at a display pattern area other than a desired display pattern, wherein a twist angle of liquid crystal layer is in a range of 50°-80°.

Yuji Souda

Papers

Liquid crystal display device with a 50 DEG -80 DEG twist angle

Liquid crystal display device with a 50°-80° twist angle

Double-Layered Super-Twisted Nematic Liquid Crystal Display for Automotive Applications

Improved VHC (Very High Contrast) LCD for Automotive Dashboard Displays