Abstract: The liquid crystal display device using guest-host interactions has. attracted interest recently because of displaying color and wide viewing angle. This paper describes dyes with high dichroic ratio, and proposes two new types of the guest-host cell being more useful than usual one. One of them is the cell with twisted molecular alignment and has sharper threshold voltage than the usual cell with homogeneous alignment. The other one with small pretilt from homeotropic alignment is made of a host nematic with negative dielectric anisotropy and is the positive type display device with high color contrast. The optimal pretilt angle of this cell is also clarified.

Abstract: An improved roadside reflector assembly which when mounted alongside a road is continuously visible by retroreflected light by the driver of a vehicle moving along the road at night-time within a viewing angle of from about 0° to 60° relative thereto, where 0° extends substantially parallelly to a tangent to the road in the region where such reflector assembly is located. Also, such driver continuously sees retroreflected light at any given instant of time while approaching and passing a group of the reflector means so employed and so located, the individual such reflector means being longitudinally spaced from one another along such a road.

Abstract: A particle size spectrometer having a fixed field of view within the forward light scattering cone at an angle θs between approximately 100 and 200 minutes of arc (preferably at 150 minutes), a spectral range extending approximately from 0.2 to 4.0 inverse micrometers (μm-1), and a spectral resolution between about 0.1 and 0.2 μm-1 (preferably toward the lower end of this range of spectral resolution), is employed to determine the distribution of particle sizes, independently of the chemical composition of the particles, from measurements of incident light, Io, at each frequency, σ (=1/λ), and scattered light, I(σ), according to the equation: ##EQU1## where l=2πsinθ, θ being the fixed viewing angle θs at which scattered light is measured, r is particle size, σ is the reciprocal of wavelength, J1 is a Bessel function of first kind and order unity, Y1 is a Bessel function of second kind and order unity. The quantity, I.sub.σ, is the ratio of scattered light to incident light at each frequency interval. The apparatus is a passive remote sensor that can be used in laboratories, field stations, flying aircrafts and airships, and on board an orbiting satellite.

Abstract: A new approach to the reconstruction of images with limited data from rotary fan-beam computed tomography (CT) scanners is presented. The missing views are estimated by reflecting the data obtained at source positions in the range (l80±fan angle) away from the desired viewing angle. Due to asymmetry of the source/ detector geometry the "reflected" views may be offset from the desired views and additional corrections are required. Measured and "reflected" views are convolved and backprojected using the standard fan-beam geometry reconstruction algorithm. This method is used to reconstruct 1.8 second images from a rotary fan-beam scanner which rotates 360° in 3 seconds, providing improved temporal resolution for dynamic CT studies with no increase in noise at a constant radiation exposure. In addition, the method is applied to ECG-gated cardiac imaging, reducing the scanning interval required for generating systolic and diastolic images by a factor of 40%.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: Remote sensing of brightness temperatures of a scattering medium composed of spherical scatterers beneath a homogeneous surface layer is studied by using Mie scattering functions. We illustrate the effects of a surface layer by plotting the brightness temperatures as functions of frequency and viewing angle for different layer thicknesses, dielectric constants, and fractional scattering volumes. It is found that the brightness temperature increases when the loss tangent of the surface layer is increased and when the fractional volume occupied by the scatterers is decreased. In the absence of a surface layer the brightness temperature is usually decreasing as a function of frequency. The presence of a homogeneous layer may cause the brightness temperature to increase with frequency. At all viewing angles the vertical polarization is brighter than the horizontal polarization.

Abstract: A DAP (Deformation of Aligned phase of Nematic) type liquid crystal display is enabled with a voltage having a periodically variable effective value. The displaying color of the DAP type liquid crystal display is changed by cyclic variation in the effective value of the applied voltage.

Abstract: A liquid-crystal display device using the depolarization phenomenon is described. The device is the same as the usual twisted nematic liquid-crystal cell (TN cell) except that a nematic liquid crystal with negative dielectric anisotropy is used. It gives high contrast and a wide viewing angle.

Abstract: A retrofocus type wide angle photographic lens is disclosed comprising eight lens elements grouped into eight lens components. The lens has an aperture ratio 1:2.5 and a viewing angle of 85°.

Abstract: SUMMARYSpectral data (350 nm-800 nm) of various crops, obtained from field plots at a low viewing angle (8° from horizontal), were normalized in 1-nm bandwidths for studying change in the spectra associated with the growth stages from early heading to maturity under field conditions. The normalized crop spectra reduced variation from the geometrical effects of viewing under different zenith, azimuth, and diffuse beam scattering situations and enabled time comparisons to be made. The data were standardized against a calibrated grey reference plate for evaluation of reflected intensities independent of measurement angles. Even after standardization, morning and afternoon radiance values were not considered comparable, indicating inherent bi-directional effects. The ratio of IR/Red radiance for bands between 600 and 800 nm and the characteristic structure in the spectral pattern near 650–700 nm were related to stage of crop growth. Radiance values in the ultraviolet range (350–400 nm) appeared to differ sign...

Abstract: The floor area required to seat various sized audiences can be computed from tables published by Eastman Kodak Company, Rochester, N.Y. 14650 [1 , 2]. Room shape is important in determining how many people can be seated in a given area within satisfactory distance and viewing angle of the screen [3]. A room with a lengthwidth ratio of 2:1 can seat more people with a comfortable viewing angle to the screen than a room with a 4:3 length-width ratio for the same floor area. For example, a room 14.6 m long and 11 m wide has a floor area of 160.6 m2 and seats 129 persons within a 50#{176} viewing angle of the screen, whereas a room 17.1 m long and 8.5 m wide has an area of 146 m2, but seats 132 persons within a 50#{176} viewing angle [1]. Aisles in the center of the audience waste optimum viewing space. If ordinances limit the length of seat rows, aisles should be located at the sides.

Abstract: A retrofocus type wide angle photographic lens is disclosed comprising eight lens elements grouped into eight lens components The lens has an aperture ratio 1:25 and a viewing angle of 85 DEG

Abstract: This paper examines the problem of distortion which arises when a projection on a screen is viewed at an angle. A quantitative parameter—the rate of variation of the viewing angle as function of th...