Gm Global Technolgoy Operations, Inc.

Hughes Aircraft Company

Nuno A Vaz

George W Smith

Thomas H VanSteenkiste

George P Montgomery, Jr

Thomas Hubert Van Steenkiste

Alan L Browne

Anna M Lackner

James L Kohler

John D Margerum

Richard A Young

Shung H Sung

Elena Ramos

Charles R Allison

A noise reduction system for a device having a noise generating subsystem includes a Helmholtz resonator and a controller. The Helmholtz resonator is disposed in fluid communication with the noise generating subsystem, and includes an active material responsive to a control signal that adjusts a dimensional characteristic of the Helmholtz resonator in such a manner as to affect a resonance characteristic of the Helmholtz resonator. The controller is responsive to an operational characteristic of either the device or the noise generating subsystem to produce the control signal. In response to the operational characteristic, the control signal serves to affect the resonance characteristic of the Helmholtz resonator in such a manner as to reduce a noise arising from the noise generating subsystem, or create a desirable sound quality alteration.

Noise reduction system

An electronic display generates an image which, through substantial registry of two opponent vector images, is perceived as a full color image. The display receives two channels of information representing two opponent color vectors of an image to be displayed, develops two images in the two opponent color vectors, and superimposes the two images to generate the image which is perceived as a full color image.

Multi-color electronic display utilizing opponent colors

A film of a polymer dispersed liquid crystal material having improved light scattering and solar attenuation properties, which utilizes a significantly reduced amount of the liquid crystal component as compared to conventional polymer dispersed liquid crystal films, is provided. These improved properties are obtained by the addition of preferably up to about three volume percent of an organic photoaccelerator chosen from the group of amines or aminobenzoates, to the liquid crystal-polymer precursor mixture prior to curing of the mixture.

Polymer dispersed liquid crystal films having improved optical

Liquid crystal films are potentially useful for automotive displays and for automotive windows and sunroofs with variable optical transmission. The present invention provides a liquid crystal material having an extended wavelength response and a method for making the same. The size of the liquid crystal microdroplets within the material are controlled such that a polydisperse liquid crystal film is formed. Controlling the curing parameters during the cure of a supersaturated mixture of liquid crystal in polymer precursor allows for the fabrication of a polymer-dispersed liquid crystal material containing a multimodal distribution of microdroplet sizes which provides a film acting as both as a visible light shutter and a strong scattered of infrared radiation.

Polymer dispersed liquid crystal material having an extended wave-length

An electrical contact for use with an optically responsive, polymer dispersed liquid crystal film is provided. The preferred electrical contact means consists of a pair of U-shaped, electrically conductive spring connectors. Each of these spring connectors is rigidly biased against corresponding transparent electrodes provided on each of the surrounding transparent substrates, so as to provide a compressive clamping force against the electrode. This ensures an intimate and complete electrical connection between each spring connector and each transparent electrode. The spring connector may be formed from any electrically conductive material which is sufficiently strong yet yielding and which is sufficiently anodic with respect to the electrode material, a preferred material being a suitable beryllium copper alloy when the electrodes are formed from a material such as indium-tin oxide. The preferred spring connector also provides redundant electrical contact between each electrode and itself, therefore, enabling its use in large area devices, such as window panels, wherein it is imperative that failure at a single point of electrical contact does not result in failure of the electrical connection.

Electrical contacts for polymer dispersed liquid crystal films

Optically responsive films comprising birefringent nematic and/or birefringent chiral nematic liquid crystal microdroplets dispersed in electron beam cured polymeric reaction products are disclosed.

Polymer dispersed liquid crystal films formed by electron beam curing

In an optical device containing material which is dielectric wherein the device is switchable between an inactive relatively opaque state and an activated relatively transparent state in response to the application of a driving electric field of sufficiently low frequency, a problem may arise in that the switching time between the inactive-opaque state and the activated-transparent state is increased and/or the light transmissivity in the activated-transparent state is decreased when the device is at a relatively low temperature. This problem is alleviated by applying a heating electric field of sufficiently high frequency as to heat the dielectric material while not switching the device to the activated-transparent state thereby raising the temperature of the device to decrease the switching time between the inactive-opaque state and the activated-transparent state and/or to increase the light transmissivity in the activated-transparent state. The dielectric material may be a polymer film containing dispersed liquid crystal droplets.

Optical device with dielectric heating

A method of forming a polymer dispersed liquid crystal (PDLC) film is disclosed which consists of forming a solution of LC dissolved in a monomer, photopolymerizing the solution to form a film having a dispersion of LC bubbles therein, establishing a correlation between the LC bubble size and selected characteristics of the film, selecting a LC bubble size corresponding to desired film characteristics, and controlling the conditions of photopolymerization to achieve said LC bubble size. The LC bubble size is controlled by means of the UV exposure intensity, exposure temperature, exposure wavelength, LC concentration and/or concentration of polymerization initiator. Correlations are noted between LC bubble size and the resulting film's threshold and operating voltages for optical transmission, contrast ratio, absolute transmissivity and electro-optical response times. Special types of films, including in situ gratings and holograms, are obtained by periodically varying the conditions of polymerization over the film to produce a corresponding periodic spatial variation in the LC bubble size; different processes used to achieve this result are noted. Films with LC bubbles in a new size regime that significantly decreases the operating voltage threshold, and with gradients in the bubble size, are also disclosed.

Polymer dispersed liquid crystal film devices, and method of forming the

In an automotive vehicle having a visual glass pane subject to collecting vision obscuring moisture in the form of ice, frost, mist, fog, etc., apparatus is provided for removing the collected moisture. Specifically, the apparatus comprises a transparent layer of dielectric material underlying the glass pane in heat conducting relationship thereto, and means for producing dielectric heating of the dielectric material to thereby heat the glass and remove the collected moisture. Preferably, the layer of dielectric material is a polymer film and the means for producing dielectric heating includes a pair of transparent electrodes extending over the layer of dielectric material. For ease of fabrication, the pair of electrodes may be interdigitated on the same side of the layer of dielectric material.

Moisture removal from visual glass surfaces by dielectric heating

A method of creating memory effect in an optically responsive film containing smectic liquid crystal microdroplets dispersed in a polymeric film by first heating it to a higher temperature such that the structure of the liquid crystal is transformed into an isotropic phase, and then cooling the liquid crystal from that higher temperature in an electric field of sufficient intensity such that the liquid crystal microdroplets remain in an aligned state of the smectic phase for a sufficiently long period of time.

Method to create memory in a dispersed smectic system

Optically responsive films comprising birefringent nematic and/or birefringent chiral nematic liquid crystal microdroplets dispersed in UV-cured polymeric reaction products of di- and/or triallyl ethers and esters and suitable polythiols are disclosed.

Growing community of inventors

West Bloomfield, MI, United States of America

Nuno A Vaz