2697 results about "Birefringence" patented technology

In a polarization maintaining multi-core optical fiber according to the present invention, structural birefringence is generated since an elliptic core is applied. In addition, each core is arranged so that a direction of a line connecting between centers of the nearest cores and a long axis direction of a field distribution in each core may be different from each other, and thereby, overlap of field distributions between the nearest cores is reduced. As a result, a crosstalk among cores is reduced.

An optical relay device, comprising a substrate, and at least one diffractive optical element is disclosed. The substrate is made, at least in part, of a light transmissive polymeric material characterized by a birefringence, Δn, satisfying the inequality |Δn|<ε, where ε is lower than the birefringence of polycarbonate. In a preferred embodiment, the light transmissive polymeric material comprises a cycloolefin polymer or a cycloolefin copolymer.

The present invention discloses simple and yet highly efficient configurations of optical coherence domain reflectometry systems. The combined use of a polarizing beam splitter with one or two polarization manipulator(s) that rotate the returned light wave polarization to an orthogonal direction, enables one to achieve high optical power delivery efficiency as well as fixed or predetermined output polarization state of the interfering light waves reaching a detector or detector array, which is especially beneficial for spectral domain optical coherence tomography. In addition, the system can be made insensitive to polarization fading resulting from the birefringence change in the sample and reference arms. Dispersion matching can also be easily achieved between the sample and the reference arm for high resolution longitudinal scanning.

A 4-membered compound is represented by the following formula (I) is disclosed (in the formula, X1 and X2 each independently represent an oxygen atom, a sulfur atom or a substituted or unsubstituted imino group, Y1 and Y2 each independently represent a single bond, an oxygen atom or a substituted or unsubstituted imino group, B1 and B2 each independently represent an optionally substituted aliphatic, aliphatic carbonyl, aromatic or aromatic carbonyl group having 1-20 carbon atoms, and A1 and A2 each independently represent a group represented by the following formula (II) (Ar1, Ar2 and Ar3 each independently represent a cyclic group having 5-14 carbon atoms, L1 and L2 each independently represent a single bond or a divalent linking group, and p represents an integer of 0-2)). There is also disclosed a birefringence medium containing a 4-membered compound represented by the formula (I) and an optical element comprising the birefringence medium.

The present invention relates to confocal self-interference microscopy. The confocal self-interference microscopy further includes a first polarizer for polarizing reflected or fluorescent light from a specimen, a first birefringence wave plate for separating the light from the first polarizer into two beams along a polarizing direction, a second polarizer for polarizing the two beams from the first birefringence wave plate, a second birefringence wave plate for separating the two beams from the second polarizer into four beams along the polarizing direction, and a third polarizer for polarizing the four beams from the second birefringence wave plate, in the existing confocal microscopy. Optic-axes of the first and second birefringence wave plates exist on the same plane, optic-axes of the first and second birefringence wave plates are inclined from an optical axis of the entire optical system at a predetermined angle, and self-interference spatial periods of the first and second birefringence wave plates are different from each other.

Several systems and a method are taught for rapid modulation of a light beam in lidar and other imaging. Most of these involve micromechanical and other very small control components. One such unit is a light-switching fabric, based on displacement of liquid in a tube that crosses a junction of two optical waveguides. In some forms, the fabric is preferably flexible to enable folding or coiling to form a two-dimensional face that interacts with optical-fiber ends an opposed fiber bundle. The rapid operation of the switch fabric enables it to be used as a beam-splitter, separating incoming and return beams; and also to form pulses from supplied CW light. Other control components include micromechanical mirrors (e. g. MEMS mirrors) operated in arrays or singly, liquid-crystal devices, and other controlled-birefringence cells. Some of these devices are placed within an optical system for directional light-beam steering.

Reflective polarization valve engine and projection display are disclosed. Instead of prism PBS, the projector applies wire-grid polarizers with advantages of higher heat-resistance, no limitation of the incident angle and no birefringence effects, to provide excellent contrast luminance. The light source in the projector utilizes an elliptical lamp under a telecentric optical system to achieve higher efficiency and avoid color gradient. In addition, the light paths are in special arrangement. The original beam is first splitted into RGB, and then proceeding with color-recombining right after being polarized via wire-grid polarizers and analyzed by reflective polarization valves. Hence, the analyzed beams finally are recombined images with superior performances.

A liquid crystal display device has an elliptic polarizer consisting of a polarizer, a first retarder, and a second retarder, and a reflector reflecting light in a visual light range. Optimal values for a twist angle of a liquid crystal layer, an angle between a transmission axis of the polarizer and a slow axis of the first retarder, an angle between the slow axis of the first retarder and a slow axis of the second retarder, and a product of birefringence .DELTA.n of liquid crystal material used in the liquid crystal layer and a thickness d of the liquid crystal layer are evaluated.

Embodiments of the invention are directed to apparatus and methods for converting spatially homogeneously polarized light into spatially inhomogeneously polarized light having a fast axis orientation that varies in a smooth and continuous manner over a pupil aperture. A space-variant waveplate referred to herein as a polarization converter includes an optically transmissive window characterized by a symmetric stress birefringence that provides at least λ/4 retardance and, more particularly, λ/2 retardance over an annular region centered about the optical axis of the window. Structural embodiments of the polarization converter include a mechanical compression housing and a thermal compression housing. Radially and azimuthally polarized vortex beams including cylindrical vector beams and counter-rotating beams can be generated from uniformly plane polarized input beams propagating through the polarization converter. Low-order polarization vortex beams can be optically combined to produce higher-order scalar vortex beams. Embodiments of the invention are also directed to various optical illumination and imaging systems utilizing the apparatus and methods described herein.

A method and apparatus for performing refractive index, birefringence and optical activity measurements of a material such as a solid, liquid, gas or thin film is disclosed. The method and apparatus can also be used to measure the properties of a reflecting surface. The disclosed apparatus has an optical ring-resonator in the form of a fiber-loop resonator, or a race-track resonator, or any waveguide-ring or other structure with a closed optical path that constitutes a cavity. A sample is introduced into the optical path of the resonator such that the light in the resonator is transmitted through the sample and relative and/or absolute shifts of the resonance frequencies or changes of the characteristics of the transmission spectrum are observed. A change in the transfer characteristics of the resonant ring, such as a shift of the resonance frequency, is related to a sample's refractive index (refractive indices) and/or change thereof. In the case of birefringence measurements, rings that have modes with two (quasi)-orthogonal (linear or circular) polarization states are used to observe the relative shifts of the resonance frequencies. A reflecting surface may be introduced in a ring resonator. The reflecting surface can be raster-scanned for the purpose of height-profiling surface features. A surface plasmon resonance may be excited and phase changes of resonant light due to binding of analytes to the reflecting surface can be determined in the frequency domain.

In order to characterize the optical characteristics of a device, a source of light having a variable frequency with a polarization state which varies linearly with frequency is provided as an input to the device under test. The input light is also passed through a known reference path and is added to the light output from the device under test in a beam combiner. The combined light for the frequencies of interest is split into two orthogonal polarizations which are then detected in a spectral acquisition apparatus and supplied to a microprocessor. The spectral measurements are digitized and curve-fitted to provide optical power versus optical frequency curves. Fourier transforms of each of the curves are calculated by the microprocessor. From the Fourier transforms, the four arrays of constants are calculated for the Jones matrix characterizing the device under test.

Multilayer thin film reflectors, such as mirrors and reflective polarizers, are described in which form birefringent optical layers are incorporated into a plurality of optical repeat units in the film. The form birefringent layers exhibit birefringence as a result of microscopic structures that have a dimension that is small compared to the wavelength of light but large compared to molecular distances. The optical layers within the optical repeat units have out-of-plane indices of refraction that are tailored to produce desired effects as a function of incidence angle for p-polarized light. The multilayer reflectors can be made by conventional vacuum deposition techniques using known inorganic optical materials, but can also be made entirely with polymeric materials by co-extrusion or other processes.

Disclosed is the use of certain polyglutarimides as plastic substrates for use in electronic display applications. These substrates have relatively high Tgs for plastics, and good optical clarity and flatness, with low shrinkage and low birefringence. Also disclosed are electronic display cells made using such polyglutarimide substrates.

[PROBLEMS] To provide a liquid crystal display device that does not need any surface aligning treatment, realizes striking increase of a response speed of movie display and is free from any light leakage (produce dark field) at black display.

[MEANS FOR SOLVING PROBLEMS] There is provided a liquid crystal display device comprising a pair of transparent substrates and, interposed therebetween, a polymer stabilized blue-phase liquid crystal. The liquid crystal display device utilizing the polymer stabilized blue-phase liquid crystal exhibits a large birefringence change upon application of an electric field to cell substrate in an in-plane direction. The polymer stabilized blue-phase liquid crystal is composed of a low-molecular liquid crystal capable of developing a blue phase between cholesteric phase and isotropic phase and a polymer network created in the low-molecular liquid crystal. Further, by optimizing the type and amount of chiral dopant added to the liquid crystal, there can be provided a liquid crystal display device that is free from any light leakage (produce dark field) at black display.

A frequency swept laser source for TEFD-OCT imaging includes an integrated clock subsystem on the optical bench with the laser source. The clock subsystem generates frequency clock signals as the optical signal is tuned over the scan band. Preferably the laser source further includes a cavity extender in its optical cavity between a tunable filter and gain medium to increase an optical distance between the tunable filter and the gain medium in order to control the location of laser intensity pattern noise. The laser also include a fiber stub that allows for control over the cavity length while also controlling birefringence in the cavity.

The present invention relates to cellulose esters having low hydroxyl content for use in optical applications, such as liquid crystal display (LCD) films. Films made with low hydroxyl levels and a given ratio of non-acetyl ester to hydroxyl level have been found to have low intrinsic birefringence. Therefore, these films can be cast, molded, or otherwise oriented without an appreciable birefringence or optical distortion (i.e. retardation). Such features make these films useful in polarizer, protective, and compensator films as well as molded optical parts, such as lenses. Furthermore, it has also been found that resins of the present invention can also be made to have “+C plate” behavior either by melt or solvent based processing, a characteristic which is not typical of cellulose esters. Such +C behavior allows films to be produced having unique compensatory behavior. Other embodiments of the invention relate to methods melt casting films while minimizing birefringence formation. Another embodiment of the invention is directed to films made from the cellulose esters described herein further comprising a plasticizer.

An illumination system for a microlithographic projection exposure apparatus has a first polarization manipulator, a second polarization manipulator and at least one optical element located between these manipulators. The polarization manipulators ensure that the direction of the electric field vector of a light ray varies in time between the polarization manipulators, whereas the polarization state is fixed outside the polarization manipulators. This prevents high energy light from inducing birefringence in optical elements arranged between the two polarization manipulators.

A method and apparatus for measuring microstructures, anistropy and birefringence in polymers using laser scattered light includes a laser which provides a beam that can be conditioned and is directed at a fiber or film which causes the beam to scatter. Backscatter light is received and processed with detectors and beam splitters to obtain data. The data is directed to a computer where it is processed to obtain information about the fiber or film, such as the birefringence and diameter. This information provides a basis for modifications to the production process to enhance the process.

The present invention relates to cellulose esters having low hydroxyl content for use in optical applications, such as liquid crystal display (LCD) films. Films made with low hydroxyl levels and a given ratio of non-acetyl ester to hydroxyl level have been found to have low intrinsic birefringence. Therefore, these films can be cast, molded, or otherwise oriented without an appreciable birefringence or optical distortion (i.e. retardation). Such features make these films useful in polarizer, protective, and compensator films as well as molded optical parts, such as lenses. Furthermore, it has also been found that resins of the present invention can also be made to have “+C plate” behavior either by melt or solvent based processing, a characteristic which is not typical of cellulose esters. Such +C behavior allows films to be produced having unique compensatory behavior. Other embodiments of the invention relate to methods melt casting films while minimizing birefringence formation.

A process of readily producing a patterned birefringent product excellent in resolution and heat-resistance is provided. Said process comprises at least the following steps [1] to [3] in order:

• • [1] preparing a birefringence pattern builder which comprises an optically anisotropic layer comprising a polymer, and said optically anisotropic layer has a retardation disappearance temperature in the range higher than 20° C.,
  • at said retardation disappearance temperature in-plane retardation becomes 30% or lower of the retardation at 20° C. of the same optically anisotropic layer, and
  • said retardation disappearance temperature rises by light exposure;
  • [2] subjecting the birefringence pattern builder to patterned light exposure;
  • [3] heating the laminated structure obtained after the step [2] at 50° C. or higher and 400° C. or lower.