7results about How to "Low birefringence" patented technology

This invention provides a resin that combines high refractive index, high heat resistance, and low birefringence. The cyclic olefin copolymer hydride of this invention is formed by hydrogenating a cyclic olefin copolymer, wherein the cyclic olefin copolymer comprises structural units from 1-naphthylnorbornene and structural units from 2-naphthylnorbornene, and the average internal bulk ratio of 1-naphthylnorbornene to 2-naphthylnorbornene is 50 mol% or more. The cyclic olefin copolymer hydride of this invention is preferably used as a material for optical components such as optical lenses.

The application provides a high-refraction cycloolefin copolymer and a preparation method thereof, and has a structure of formula I. The cycloolefin copolymer can obtain a cycloolefin copolymer resin with high thermal stability due to high steric hindrance of the cycloolefin monomer. The refractive index of the cycloolefin copolymer resin is greatly improved due to R3 and R4 on the cycloolefin monomer, and is first broken through to above 1.70, while maintaining high light transmittance of 91.0-96.0%, extremely low water absorption (<0.01%), and a glass transition temperature of 219 DEG C. The application prepares the cycloolefin copolymer resin with high activity, adjustable molecular weight and glass transition temperature by adjusting the reaction conditions. The copolymer resin has high refractive index, high light transmittance, heat resistance, low birefringence and moisture absorption, excellent fluidity, moldability and dimensional stability.

The present invention relates to liquid crystal (LC) mixtures or LC materials based on mixtures of polar compounds, the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays, in particular in fringing field switching mode LC displays, to fringing field switching mode LC displays comprising said LC media, and to a method for producing said LC displays.

The purpose of the present invention is to provide: a cyclic olefin ring-opening polymer hydride which has both an Abbe number of an appropriate size and a low birefringence; and a starting material for the cyclic olefin ring-opening polymer hydride. This cyclic olefin ring-opened polymer is characterized by containing a structural unit (A) derived from a norbornene imide monomer represented by formula (1) and a structural unit (B) derived from a cyclic olefin monomer that does not have a polar group. The cyclic olefin ring-opening polymer hydride according to the present invention is characterized by being obtained by hydrogenating the cyclic olefin ring-opening polymer according to the present invention.

The object of this invention is to provide a cyclic olefin ring-opening polymer hydride with a suitable Abbe number and low birefringence, and the raw materials thereof. The cyclic olefin ring-opening polymer of this invention is characterized by comprising structural units (A) from 1,2,3,3a,4,6a-hexahydro-1,2,4-methyl-bridged pentanene and structural units (B) from a cyclic olefin monomer having an aromatic ring structure. Furthermore, the cyclic olefin ring-opening polymer hydride of this invention is characterized by being formed by hydrogenating the cyclic olefin ring-opening polymer of this invention.

The invention relates to the technical field of optical devices. The invention relates to a wave plate, in particular to a wave plate suitable for middle and far infrared bands and application thereof. The wave plate is prepared by using a cesium-cadmium-chlorine optical crystal as a birefringent matrix material, the chemical formula of the cesium-cadmium-chlorine optical crystal is CsCdCl3, the space group of the cesium-cadmium-chlorine optical crystal is P63 / mmc, the cesium-cadmium-chlorine optical crystal belongs to a hexagonal system, and the cell parameters of the cesium-cadmium-chlorine optical crystal are as follows: a = b = 7.418, c = 18.39, Z = 6, alpha = beta = 90 degrees, and gamma = 120 degrees. As the cesium-cadmium-chlorine optical crystal has higher transmittance and smaller birefringence in a long-wave infrared band, the prepared wave plate has larger thickness size, is convenient to process, is suitable for being used in middle and far infrared bands, has important application prospects in the fields of optics and optical communication, and has wide application prospects. Various optical devices such as optical attenuators, polarization state generators and polarization direction rotators can be prepared.

The invention belongs to the technical field of crystal material preparation, and particularly relates to a method for growing sapphire crystals by a wide seed crystal edge-defined film-fed crystal growth method, which comprises the following steps of: firstly, preparing an Al2O3-based raw material through multi-step sintering, carrying out acid etching microstructuring treatment on R / M surface seed crystals, arranging an array type feeding seam mold above a crucible during charging, and carrying out vacuum replacement for three times, so as to obtain a sapphire crystal; a gradient temperature field is established through three-area independent temperature control, seeding is performed after melt is immersed into a mold, the growth process comprises seeding, shouldering and equal-diameter growth, wide diameter expansion and equal-diameter growth of crystals are realized by accurately controlling the pulling rate, the crucible rising speed and the three-section power of a middle heating area, and the crystals are automatically separated from the mold; and high-temperature, medium-temperature and low-temperature three-stage gradient annealing is carried out under argon protection to release stress and stabilize the structure, so that the transverse temperature gradient can be accurately controlled below 5 DEG C / cm, the problem of large temperature difference between the edge and the center during wide seed crystal growth is solved, and the stability of the solid-liquid interface shape and the uniformity of crystal growth are ensured.