Showing papers on "Tilt (optics) published in 1986"

Depth response of confocal optical microscopes.

Abstract: The on-axis intensity response of a confocal scanning optical microscope was measured for an objective of numerical aperture 0.9. The data compare favorably with theoretical calculations obtained by numerical integration of the standard theory, provided that lens aberrations are taken into account. The invariance of the shape of the central lobe to surface roughness and tilt is also demonstrated.

Tilt and swivel support

Abstract: A tilt and swivel apparatus supports a structure such as a CRT display device above a stable base. Separate tilt and swivel mechanisms are provided to improve the stability of the apparatus. Stop elements limit the extent of tilting and rotation which is permitted. An internal passage is provided for cable connections to the supported structure.

Observation and interpretation of the atomic structure of a [Sgrave] = 19/[110] (331) tilt boundary in Au thin films

Abstract: The atomic structure of a (331) [Sgrave] = 19/[110] tilt boundary prepared from an Au bicrystal has been investigated by very high resolution transmission electron microscopy. It has also been possible to confirm independently the type of contrast obtained in such a micrograph by dynamical diffraction and computer image simulations and correlate the image features to the atomic position data. Close agreement has been achieved between two relaxed boundary structure models and the computer-enhanced [Sgrave]=19 micrograph viewed along the tilt axis direction. Direct measurements of the interfacial dilatation of the (331) planes parallel to the interface and the relative translations of the two crystals on either side of the interface have also been made.

Refractive Changes Induced by Intraocular Lens Tilt and Longitudinal Displacement

Abstract: • There is a tendency for the posterior chamber intraocular lens to tilt about the points of insertion. This is found clinically and in postmortem studies of eyes that have had intraocular lenses surgically implanted. One end is often located in the lens capsule and the other end is located in the ciliary sulcus. The possibility of anteroposterior displacement also exists. Using a modified Gullstrand schematic model eye, we have computed the amount of spherical and cylindrical errors that are induced due to the tilt and/or displacement of the intraocular lens. If a cylindrical error of approximately 90° from the axis of insertion (lens plus haptic loops) and/or axis of tilt is detected, further careful investigation is warranted.

Single gyro northfinder

Abstract: Disclosed is a northfinding apparatus having a single rotation rate sensor secured to a platform. The output of the rotation rate sensor is corrected for tilt and tilt rate of the platform. Measurements of the tilt and tilt rate and the rotation rate are combined to provide an azimuth angle of the platform relative to north.

Tilt and splay of surfactants on surfaces.

Abstract: The energy of a monolayer of surfactant on a surface is calculated as a function of the orientation of the surfactant tails. The structure is determined by a competition between the spacings preferred by the polar heads and nonpolar tails. As a function of the head-tail mismatch, we find a region of no molecular tilt, and one of uniform tilt. In the tilted state, solitonlike defects resembling micellar clusters are stabilized by entropy or finite-size effects.

Modeling of injection-locking phenomena in diode-laser arrays

Abstract: We report the first self-consistent numerical model to our knowledge of the injection-locking process in a gain-guided diode-laser array. This model reproduces two essential features of device behavior seen in recent experiments: (1) the single-lobed far-field output beam that results from injecting a single end-element of the array and (2) the linear dependence of the far-field beam angle on injection frequency. This angular scanning of the far-field beam angle can be understood on the basis of a simple plane-wave picture in which a change in the injection frequency leads to a tilt of the wave front in the diode-laser array in order to maintain the Fabry–Perot resonance condition.

Pan and tilt mount

Abstract: The invention is directed to a highly accurate remote positionable pan and tilt mount for a television camera or the like. The pan and tilt portions are rotated by stepping motors. The pan portion can be continuously rotated in either direction through 360°.

Talbot interferometry for measuring the small tilt angle variation of an object surface.

Abstract: In measuring the small tilt angle of a surface, an autocollimator is generally used. It is difficult to measure the local variation of tilt angles of a large object surface because the area of measurement is limited. In this Letter we present a simple method for measuring the small tilt angle variation of an object surface. The principle of the method is based on Talbot interferometry. The use of Talbot interferometry as a method for deflection mapping of phase objects and for measuring the focal length of lenses has been reported by the authors. The sensitivity of the Talbot interferometry can be easily tuned by varying the crossed angle between two gratings, and the optical system is rather simple. Figure 1 shows a schematic representation of the optical

Measurements of tilt angle and heat capacity in the vicinity of one smectic-A-chiral-smectic-C transition

Abstract: Both high-resolution heat-capacity and tilt-angle measurements have been carried out near the smectic-A--chiral--smectic-C transition of p-(n-decyloxy)benzylidene-p-amino-(2-methlbutyl)cinnamate (DOBAMBC). The extended mean-field theory, suggested by Huang and Viner, for the smectic-A--smectic-C (or chiral--smectic-C) transition, requires a unique relationship between the tilt angle and the anomalous part of the heat capacity. Here we demonstrate this relationship by our experimental results on both heat capacity and tilt angle. This provides a strong additional support for the extended mean-field model in describing the smectic-A--chiral--smectic-C transition.

Topographic effect on tilt, strain, and displacement measurements

Abstract: Deformation and stress fields are locally modified by the presense of topography. An approximate analytical method is used to give simple expressions for the effect of arbitrarily shaped topography on vertical, horizontal, and surface tilt measurements. This provides a means of making corrections to observations without the use of finite element techniques. Corrections to tilt fields are found to be directly proportional to the local slope of the topography. Comparison is made between expressions for tilt and those for strain and displacement. Although the topographic effects on secular tilt, strain, and vertical displacement are not yet measurable, we emphasize that the topographic effect on precision tidal tilt and strain measurements can be significant.

On Irradiance Measurement Errors at Sea Due to Tilt of Pyranometers

Abstract: Calculations are made of errors in the measurement of solar irradiance at the sea surface. which occur when pyranometers are tilled. Tilts due to buoy or ship motion caused by wave action or a preferential tilt due to drag are considered. Errors depend on sky condition and are maximum for clear skies. They depend on soar zenith angle and on the relative azimuth of sun and tilt directions, and vary, therefore, with latitude and season or time of day. Errors as large as ±10% to ±20% in the daily average (with sign dependent on azimuth of the tilt) could be encountered for clear skies poleward of 45°N or S in the winter half of the year for a 10° preferential tilt. Instantaneous errors due to wave action can be as large. Because of the difficulty of making corrections a posteriori, gimbal mounting of pyranometers is recommended.

Liquid crystal orientation controlling film and liquid crystal device using the same

Abstract: A liquid crystal display device containing a liquid crystal orientation controlling film made from a fluorine-containing polyimide-isoindoloquinazolinedione is high in a tilt angle and excellent in viewing properties.

Segment Alignment For The Keck Telescope Primary Mirror

Abstract: We propose to use a Shack-Hartmann camera to align and phase the thirty-six segments of the ten meter primary mirror of the Keck Telescope. Tilt errors are determined by employing the Shack-Hartmann device in a manner exactly analogous to that used in mirror testing and in adaptive optics. Piston errors are determined (with the same device) by exploiting diffraction effects near the intersegment edges. These two tests are shown to have sensitivities that are comparable to each other and that are sufficient to achieve the design goals of the telescope. We describe how the tilt test can be extended to give information both about the individual segment figures and about the global mirror parameters. Some of the complications and potential systematic effects associated with these tests are discussed.

Pickup unit for use in an optical information record/reproduce system

Abstract: A pickup unit for use in an optical information record/reproduce system comprising a plurality of optical elements including a light-emitting device and an objective lens by which the light issuing from the light-emitting device is focused as a beam spot on the recording surface of a recording medium, a retaining mechanism that holds the plurality of optical elements and which is movable in a direction parallel to the recording surface, and a tilt servo mechanism for causing the optical axis of the beam spot to intersect the recording surface at right angles. The tilt servo mechanism includes a sensor for detecting the angle of inclination of the optical axis in relation to the recording surface. The sensor has a sensor stay as an integral part thereof. The sensor stay is provided as an integral part of the retaining mechanism and is movable with respect to the recording surface.

An Optical Phase Reconstructor Based On Using A Multiplier-Accumulator Approach

Abstract: Phase sensors that are most commonly used in the adaptive-optics area typically measure the gradient of the phase. A phase reconstructor is necessary to obtain the phase at the actuator positions of the deformable mirror. In the past reconstructors to obtain the optical phase from gradient measurements have been built using resistive nets. These nets simulate a least-squares reconstruction algorithm. There are other algorithms which can be used to mate wavefront sensors and deformable mirrors with different geometries or which can improve the noise performance by using the spatial correlation of the phase. These types of algorithms are difficult to implement and change using analog techniques. In addition, since the movement of an actuator can influence the position of adjacent actuators it is desirable to include this effect in the reconstructor. One may also want to remove the piston and the tip and tilt from the signal applied to the deformable mirror, and determine the values of the focus and tip and tilt terms in order to provide signals to auxiliary mirrors. A digital reconstructor can provide this capability. An approach to a digital reconstructor which can calculate an optical phase which is any linear function of the gradient measurements is described. This reconstructor is based on using a multiplier-accumulator circuit in each channel. A single phase value is calculated in each channel by summing the result of multiplying each gradient measurement by a stored matrix coefficient. Several sets of matrix coefficients are stored in memory to allow one to change the reconstruction algorithm quickly. The circuitry used and the time taken to perform the reconstruction will be described.

Three-axis sample manipulator with XYZ translation for use in UHV

Abstract: A three‐axis manipulator suitable for atom diffraction experiments has been constructed by combining three modules with translation, polar rotation, and azimuthal‐tilt rotation capabilities. No magnetic materials are used and materials have been chosen to minimize the possibility of galling in vacuum. Azimuthal rotations of up to ±110°, tilt rotations of up to ±30°, and polar rotations of ±180° are possible with the manipulator. The Z motion is ±2 in. and XY motions of 10 mm lead to a change in azimuthal and tilt angles of less than one degree. The sample is heated with electron bombardment and can be cooled to 80 K.

Ferroelectric smectic c mixture, method for controlling its tilt angle, and light switching element

Abstract: A method of controlling the tilt angle of ferro­electric chiral smectic C (S C *) phase of a liquid crystal mixture is provided by making smectic A (S A ) phase present in the mixture to thereby control the tilt angle to 16 - 29°, or by making S A phase absent therein to thereby control the angle to 32 - 58°, the former method being suitably applied to birefringence display and the latter, to guest-host display, the ferroelectric smectic C mixture obtained in the method and a light switch­ing element using said mixture are disclosed.

Optimum energy model for tillage

Abstract: An optimum energy model has been given, for a soil—tool system where the soil is non-uniform, and the tool width, depth of cut, tilt angle, approach angle and forward velocity vary. The objective function of the energy model is based upon a force prediction equation, which necessitates quantification of analog values using a distorted model of the tillage tool whose performance is to be evaluated.

Reverse-wave suppressor mirror effects on cw HF unstable ring laser performance.

Abstract: The effect of a reverse-wave suppressor (RWS) mirror on the performance of a multiline cw HF ring laser was measured and theoretically discussed. Forward-wave far-field brightness was found to be very sensitive to the tilt of a conventional RWS mirror, being reduced by a factor of 2 for a 200-μrad RWS tilt. An aberrated mirror was found to reduce this tilt senstivity by nearly an order of magnitude. Also discussed is a possible mechanism whereby the tilt of the conventional RWS mirror reinforced a higher-order mode in the forward-wave output, yet the tilt of the aberrated mirror did not.

Detecting device for tilt angle of paper or the like

Abstract: PURPOSE:To detect accurately the tilt angle of paper currency on a conveyance path to its conveyance direction by detecting the position shift in the direction crossing the conveyance direction at right angles at two points on one side of the paper currency facing in the conveyance direction. CONSTITUTION:When photosensor groups of photosensor arrays SB and SD turn on, it is judged that the paper currency arrives on sensors. Then when it is judged that the paper currency is positioned on the photosensor arrays while the two sides of DE and FG facing in the conveyance direction cross measurement lines AC and BD, the position shift l2 in the measurement line direction is calculated at two points A and B. Then, apparent length l3 is found. The tilt angle theta is calculated from the orthogonal relation between (direction of measurement line) and (conveyance direction) and the actual length l of the paper currency is calculated from the tilt angle theta. Then, a decision on the paper currency length is made by using the length l and it is judged whether the length l satisfies an expression or not; when so, it is considered that the kind of the paper currency is normal and the conveyance of the paper currency is carried on. When not, it is considered that the kind of the paper currency is different and the paper currency is collected.

Detector for tilt angle of plane

Abstract: PURPOSE:To detect a tilt angle of an objective plane with reference to an optional reference direction under noncontact state by measuring the distance to the objective plane from the different four directions with a distance measuring means. CONSTITUTION:A part of rays from luminous elements 1-4 is photodetected directly with a photodetecting element 9 as the reference rays and a part of the rest is reflected by the objective plane A and photodetected with a photodetecting element 10. The rays photodetected with respective elements 9 and 10 are mixed with a signal sent from a local oscillation circuit 21 with mixer circuits 14 and 18 and transmitted through filters 15 and 19. After that, the rays are further transmitted through waveform shaping parts 16 and 20, and outputted as rectangular waves. The phase difference between these two rectangular waves is proportioned to the optical path difference between the reference rays and reflected rays. These rectangular waves are sent to a gate circuit 24. Then, a control and arithmetic circuit 25 counts a clock signal outputted from the circuit 24 and stores the value for every measured rays P1-P4. These stored values are proportioned to the distance from a sensor main body to the objective plane A. Accordingly, the tilt angle of the objective plane A is calculated based on the measured values with the circuit 25.

Stability of compact‐torus ion‐ring hybrid systems to magnetohydrodynamic tilt and shift modes

Abstract: The low‐frequency stability of a compact‐torus ion‐ring hybrid configuration, in which part of the toroidal current is carried by a ring of high‐energy ions, is studied. In particular, the magnetohydrodynamic (MHD) tilt and radial shift instabilities in spheromak‐like hybrid systems are considered. The ion ring has a stabilizing effect on the tilt mode, through its modification of the magnetic geometry. For the shift mode, the stabilization is dynamic for moderate elongation, but is again geometrical in the limit of large elongation. For moderate elongation, it is found that a high‐energy ion component substantially enhances stability against the MHD shift mode.