University of Rochester

Byelocorp Scientific, Inc.

Optical Shields, Inc.

Byelocorp, Inc.

Stephen D Jacobs

Kenneth L Marshall

Igor Victorovich Prokhorov

Tanya Z Kosc

Gennadii Rafailovich Gorodkin

Donald Golini

Tvasta David Strafford

William Kordonski

Kathleen A Cerqua

Anka Trajkovska-Petkoska

Sadeg Mustafa Faris

James L Fergason

Arthur Louis Berman

Le Li

Gerald Philip Cox

Shai Negev Shafrir

Hong Yang

John C Lambropoulos

Cathy A Fromen

Chunlin Miao

Jae-Cheul Lee

Mimi Wang

Rui Shen

Joni Mici

A magnetorheological material comprises a magnetic particle and a ceramic material, wherein the magnetorheological material is in a dried form and further wherein a portion of the ceramic material is in the form of a nanocrystalline coating over the entire exterior surface of the magnetic particle and another portion of the ceramic material is in the form of a free nanocrystal. A magnetorheological material comprises a magnetic particle having a ceramic material coating over an external surface thereof as a result of a coating process, and a free nanocrystal of the ceramic material in the form of a residual by-product of the coating process. A sol-gel process for making a magnetorheological product comprises providing a sol of a desired ceramic coating material; combining a desired quantity of carbonyl iron (CI) particles with the sol to coat the CI particles with the ceramic coating material; creating a resulting quantity of nanocrystalline ceramic material-coated CI particles and a quantity of free nanocrystals of the ceramic material; and, drying the resulting quantity of coated CI particles and free nanocrystals to a moisture content equal to or less than 2 wt %.

Magnetorheological materials, method for making, and applications thereof

A PCLC flake/fluid host suspension that enables dual-frequency, reverse drive reorientation and relaxation of the PCLC flakes is composed of a fluid host that is a mixture of: 94 to 99.5 wt % of a non-aqueous fluid medium having a dielectric constant value &#x2208;, where 1&#x3c;&#x2208;&#x3c;7, a conductivity value &#x3c3;, where 10&#x3e;&#x3c3;&#x3e;10Siemens per meter (S/m), and a resistivity r, where 10&#x3e;r&#x3e;10ohm-meters (&#x3a9;-m), and which is optically transparent in a selected wavelength range &#x394;&#x3bb;; 0.0025 to 0.25 wt % of an inorganic chloride salt; 0.0475 to 4.75 wt % water; and 0.25 to 2 wt % of an anionic surfactant; and 1 to 5 wt % of PCLC flakes suspended in the fluid host mixture. Various encapsulation forms and methods are disclosed including a Basic test cell, a Microwell, a Microcube, Direct encapsulation (I), Direct encapsulation (II), and Coacervation encapsulation. Applications to display devices are disclosed.

PCLC flake-based apparatus and method

Doped electrically actuatable (electrically addressable or switchable) polymer flakes have enhanced and controllable electric field induced motion by virtue of doping a polymer material that functions as the base flake matrix with either a distribution of insoluble dopant particles or a dopant material that is completely soluble in the base flake matrix. The base flake matrix may be a polymer liquid crystal material, and the dopants generally have higher dielectric permittivity and/or conductivity than the electrically actuatable polymer base flake matrix. The dopant distribution within the base flake matrix may be either homogeneous or non-homogeneous. In the latter case, the non-homogeneous distribution of dopant provides a dielectric permittivity and/or conductivity gradient within the body of the flakes. The dopant can also be a carbon-containing material (either soluble or insoluble in the base flake matrix) that absorbs light so as to reduce the unpolarized scattered light component reflected from the flakes, thereby enhancing the effective intensity of circularly polarized light reflected from the flakes when the flakes are oriented into a light reflecting state. Electro-optic devices contain these doped flakes suspended in a host fluid can be addressed with an applied electric field, thus controlling the orientation of the flakes between a bright reflecting state and a non-reflecting dark state.

Electrically actuatable doped polymer flakes and electrically addressable optical devices using suspensions of doped polymer flakes in a fluid host

Precisely configured, especially of geometric shape, flakes of liquid crystal material are made using a mechanically flexible polymer mold with wells having shapes which are precisely configured by making the mold with a photolithographically manufactured or laser printed master. The polymer liquid crystal is poured into the wells in the flexible mold. When the liquid crystal material has solidified, the flexible mold is bent and the flakes are released and collected for use in making an electrooptical cell utilizing the liquid crystal flakes as the active element therein.

Method for making precisely configured flakes useful in optical devices

Optical devices utilizing flakes (also called platelets) suspended in a host fluid have optical characteristics, such as reflective properties, which are angular dependent in response to an AC field. The reflectivity may be Bragg-like, and the characteristics are obtained through the use of flakes of liquid crystal material, such as polymer liquid crystal (PLC) materials including polymer cholesteric liquid crystal (PCLC) and polymer nematic liquid crystal (PNLC) material or birefringent polymers (BP). The host fluid may be propylene carbonate, poly(ethylene glycol) or other fluids or fluid mixtures having fluid conductivity to support conductivity in the flake/host system. AC field dependent rotation of 90&#xb0; can be obtained at rates and field intensities dependent upon the frequency and magnitude of the AC field. The devices are useful in providing displays, polarizers, filters, spatial light modulators and wherever switchable polarizing, reflecting, and transmission properties are desired.

Optical devices having flakes suspended in a host fluid to provide a flake/fluid system providing flakes with angularly dependent optical properties in response to an alternating current electric field due to the dielectric properties of the system

Composite or layered flakes having a plurality of layers of different materials, which may be dielectric materials, conductive materials, or liquid crystalline materials suspended in a fluid host and subjected to an electric field, provide optical effects dependent upon the angle or orientation of the flakes in the applied electric field. The optical effects depend upon the composition and thickness of the layers, producing reflectance, interference, additive and/or subtractive color effects. The composition of layered flakes may also be selected to enhance and/or alter the dielectric properties of flakes, whereby flake motion in an electric field is also enhanced and/or altered. The devices are useful as active electro-optical displays, polarizers, filters, light modulators, and wherever controllable polarizing, reflecting and transmissive optical properties are desired.

Electrically addressable optical devices using a system of composite layered flakes suspended in a fluid host to obtain angularly dependent optical effects

Flakes or platelets of polymer liquid crystals (PLC) or other birefringent polymers (BP) suspended in a fluid host medium constitute a system that can function as the active element in an electrically switchable optical device when the suspension is either contained between a pair of rigid substrates bearing transparent conductive coatings or dispersed as microcapsules within the body of a flexible host polymer. Optical properties of these flake materials include large effective optical path length, different polarization states and high angular sensitivity in their selective reflection or birefringence. The flakes or platelets of these devices need only a 3-20&deg; rotation about the normal to the cell surface to achieve switching characteristics obtainable with prior devices using particle rotation or translation.

Electrically switchable polymer liquid crystal and polymer birefringent flake in fluid host systems and optical devices utilizing same

A method and apparatus for finishing a workpiece surface using MR fluid is provided wherein the workpiece is positioned near a carrier surface such that a converging gap is defined between a portion of the workpiece surface and the carrier surface; a magnetic field is applied substantially at said gap; a flow of stiffened MR fluid is introduced into said converging gap such that a work zone is created in the MR fluid to form a sub-aperture transient finishing tool for engaging and causing material removal at the portion of the workpiece surface; and the workpiece or the work zone is moved relative to the other to expose different portions of the workpiece surface to the work zone for predetermined time periods to selectively finish said portions of said workpiece surface to predetermined degrees.

Deterministic magnetorheological finishing

Apparatus deterministic magnetorheological finishing of workpieces

A magnetorheological fluid comprises non-colloidal magnetic particles, an abrasive, water, glycerol, and an alkaline buffer. The abrasive may be CeO.sub.2, the non-colloidal magnetic particles may be carbonyl iron, and the alkaline buffer may be Na.sub.2 CO.sub.3. The fluid is useful for magnetorheological finishing.

Magnetorheological fluid composition

Method and apparatus using magnetorheological fluid for finishing a non-image-forming edge of an optical element to a very high degree of smoothness and for removing microscopic fissures from such edges, the method comprising positioning an optical element near a continuous carrier surface such that a converging gap is defined between an edge of the optical element and the carrier surface, the element being disposed such that image-forming refractive and reflective surfaces thereof do not create a gap with the carrier surface; applying a magnetic field substantially at the gap; introducing a magnetorheological fluid onto the carrier surface; driving the magnetorheological fluid through the gap to cause a flow of magnetic field-stiffened magnetorheological fluid through this gap to create a work zone and to form a transient finishing tool for removing material from the edge of the optical element; and moving the optical element relative to the work zone to expose different portions of the edge to the fluid for predetermined time periods to finish the edge to a predetermined degree. The lateral extent of fluid may be broad enough to permit polishing of a plurality of optical elements simultaneously on a single carrier surface, or a plurality of finishing stations may be ganged to finish a plurality of optical elements on a plurality of carrier surfaces.

Magnetorheological finishing of edges of optical elements

A polarizer including liquid crystal material and a surface or surfaces for cooperating with the liquid crystal material to control polarization of light which is incident in a direction normal to the polarizer by at least one of refraction and total internal reflection of one polarization component of the light while transmitting the other polarization component substantially in the direction without refraction or total internal reflection, the surface or surfaces including plural grooves in cooperative relationship with the liquid crystal material.

Liquid crystal light polarizer and method

Laser beam apodizers using cholesteric liquid crystals provides soft edge profile by use of two separate cholesteric liquid crystal mixtures with different selective reflection bands which in an overlap region have a gradient index where reflectivity changes as a function of position. The apodizers can be configured as a one-dimensional beam apod

Gradient index liquid crystal devices and method of fabrication thereof

Composite optical devices using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T.sub.g) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device.

Growing community of inventors

Pittsford, NY, United States of America

Stephen D Jacobs