Nitto-denko Corporation

Oplink Communications, Inc.

Accumux Technologies, Inc.

Santa Barbara Photonics, Inc.

Pochi Yeh

Scott Patrick Campbell

Yuri A Bobrov

Alla Y Sakharova

Michael V Paukshto

Zhiling Xu

Pavel Ivan Lazarev

Louis D Silverstein

Claire Gu

The compensator design, which comprises at least two layers of birefringent material, one of them is a positive A-plate and another one is a negative A-plate, makes possible a significant improvement in color rendering properties and contrast ratios of liquid crystal displays over a wide range of viewing angle.

Retardation films for the elimination of leakage of light through cross polarizers in LCD

Devices of information displays, in particular liquid crystal displays, which can be utilized in indication devices for various purposes. Liquid crystal displays, according to this disclosure, contain at least one layer of liquid crystal placed between two plates, on each plate there has been formed or applied at least one electrode or a system of electrodes, or an active matrix, and at least one layer of polarizer; while at least one polarizing layer is an E-type polarizer and at least one polarizing layer is an O-type polarizer.

Liquid crystal display including O-type and E-type polarizer

The present invention relates to the field of color filters, in particular, to a non-absorbing polarization color filters and to high-brightness color liquid crystal display panel with improved image contrast employing non-absorbing polarization color filters and light recycling among neighboring subpixels. The disclosed invention represents a non-absorbing polarization color filter comprising the following elements: a rear broadband multilayer lossless polarizer, a front broadband multilayer lossless polarizer, and a color polarization rotator. The rear broadband multilayer lossless polarizer has a predefined-oriented transmission axis AB. Said front broadband multilayer lossless polarizer is located approximately in parallel with the rear broadband multilayer lossless polarizer, and has a transmission axis approximately parallel or approximately orthogonal with respect to transmission axis AB. The color polarization rotator is located between the front broadband multilayer lossless polarizer and the rear broadband multilayer lossless polarizer. Said color polarization rotator comprises a stack of thin birefringent films with c-axes orientations alternated in sign according to a rocking angle &#x3b1; with respect to orientation of the transmission axis AB. A number, a rocking angle &#x3b1;, thicknesses and optical anisotropies of thin birefringent films are selected so, that the non-absorbing polarization color filter transmits a predetermined color light having the polarization state approximately parallel to transmission axis AB, reflects said predetermined color light having the polarization state orthogonal to the transmission axis AB, and reflects an unpolarized light of other predetermined color.

Non-absorbing polarization color filter and liquid crystal display incorporating the same

The disclosure pertains to the devices of information displays, in particular liquid crystal displays, and could be utilized in indication devices for various purposes. Liquid crystal displays, according to this disclosure, contain at least one layer of liquid crystal placed between two plates, on each plates there has been formed or applied at least one electrode or a system of electrodes, or an active matrix, and at least one layer of polarizer; while at least one polarizing layer is the E-type polarizer and at least one polarizing layer is an O-type polarizer. The polarizer, according to the invention, consists of at least two polarizers, at least one of which is the E-type polarizer and at least one is the O-type polarizer.

A chromatic dispersion compensator comprises a beam delay element, such as one or more Gires-Tournois etalon (GTEs); a beam director, such as a polarizing beam splitter (PBS), a prism polarizer, a dielectric polarizer or a crystal polarizer; and a polarization changer, such as one or more quarter-wave plates. The beam director directs an inbound optical beam based on its polarization toward the beam delay element whereat a first unit of group delay is induced. The optical beam traverses the beam delay element and enters a polarization changer whereat the optical beam obtains a new polarization. The optical beam traverses the polarization changer and re-enters the beam director whereupon a path change is induced on the optical beam based on its new polarization and the optical beam is redirected toward the beam delay element whereat a second unit of group delay is induced. The compensator is arranged to advantageously perform the referenced technique contemporaneously on two constituent optical beams (having different polarizations) of an inbound optical beam and eventually re-combine the two constituent optical beams into an outbound optical beam. The beam delay element may include one or more GTEs. Inducement of path changes and direction of the optical beam to the beam delay element may be assisted by one or more ninety degree mirrors. The referenced technique may be performed on an optical beam more than twice, such that a third, fourth, fifth, etc. delay is induced on the optical beam.

Chromatic dispersion compensator

A spectral interleaver providing flat top spectral transmission passbands and athermal operation is disclosed. The spectral interleaver may comprise a pentagon-shaped birefringent crystal, a polarization beam splitter, and a dielectric mirror at one facet of the crystal. Prisms and polarizing beam splitters can be employed for operation with an unpolarized input beam. The cavity formed by the mirror and the crystal serves as a spectrally dispersive mirror. Front mirror reflectivity is provided by the air-crystal (or other medium-crystal) interface. Proper mirror reflectivities can be achieved by selecting the angle &#x3b8; of the pentagon-shape crystal. By selecting the proper air space between the mirror and the crystal surface and the crystal length, the interleaver can have a flat top transmission function. A combination of two different crystals which exhibit different thermal-optic effects may be employed such that the total phase retardation is independent of the temperature, leading to athermal operation.

Athermal birefringent optical interleavers with flat-top passbands

Multi-stage, all-pass optical filters used to make low-loss, multi-channel dispersion compensation modules are disclosed. The all-pass optical filters can be ring resonators in waveguides, Gires-Tournois Interferometers (GTIs) in free space form, and the like. The coupling constants and circulating path lengths may also be distinctively varied in each of the series of GTIs, tuning the net dispersion spectrum of the GTI set, such that the sum of the dispersions from the series of GTI's can provide a system with greater bandwidth than the same number of identical GTIs. The local dispersion slope can also be tuned in this manner. Multi-cavity GTIs can also be formed with similar performance enhancing properties.

Dispersion compensation using resonant cavities

Fine-tuning of the optical path length in etalon cavities is achieved by slight variations of the cavity's index of refraction. Such index of refraction variations are accomplished by varying the relative gas mixture in gas-gap etalons or UV-exposing doped glass layer(s) in solid etalons or gas-gap&plus;glass etalons.

Optical path length tuning methods in etalons

The present invention provides a liquid crystal display apparatus and a method for viewing liquid crystal displays over a wide range of viewing angles with minimal loss in image contrast and gray level. Prior art liquid crystal displays (LCDs) exhibit low contrast and gray level inversion when viewed at large viewing angles. Prior art solutions to these problems include using a phase retardation plate or film interposed between the liquid crystal layer and a polarizer layer as an optical compensator. While such a solution improves image contrast and reduces some undesirable angular effects, the fabrication of such phase retardation compensator films requires precise thickness control and is expensive. The present invention discloses that by tilting the absorption axis of the birefringent polymer molecules comprising the polarizer sheet to orient at an appropriate angle relative to the liquid crystal image display panel, the contrast ratios and the gray level stability are substantially improved for wide angle viewing. For projection displays, absorption axis tilting (tilting) can be done by simply tilting the plane of a standard polarizer sheet relative to the plane of the LC image display. For flat panel displays, tilting can be accomplished by using a new type of sheet polarizer in which the long axis of the parallel chains of polymer molecules within the sheet are tilted relative to the physical plane occupied by the polarizer sheet and the adjacent coplanar liquid crystal layer.

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Thousand Oaks, CA, United States of America

Pochi Yeh