US 12,624,142 B2Granted

Optical polymer material, optical film, display device, optical polymer material manufacturing method, and optical film manufacturing method

AssigneesYasuhiro Koike, Tosoh Corporation

InventorsYasuhiro Koike, Yuma Kobayashi, Kohei Watanabe

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Abstract

An optical polymer material includes an alternating copolymer made of a monomer of a styrene derivative and a monomer of a maleimide derivative, and has a nonlinear property in which the photoelastic coefficient of the optical polymer material decreases to a predetermined value with increase in composition ratio of the styrene derivative, and rises above the predetermined value with further increase in composition ratio of the styrene derivative. A composition ratio of the styrene derivative is within a predetermined range. An absolute value of the photoelastic coefficient is equal to or smaller than a first absolute value within the predetermined range of the composition ratio, and an absolute value of the intrinsic birefringence is equal to or smaller than a second absolute value of the optical polymer material within the predetermined range of the composition ratio.

Claims11

Dependent claims

A low birefringence optical polymer material comprising an alternating copolymer comprising a monomer of a styrene derivative and a monomer of at least one maleimide derivative, wherein

(a) the optical polymer material exhibits a nonlinear property in which a photoelastic coefficient of the optical polymer material decreases to a minimum value with an increase in composition ratio of the styrene derivative, and rises above the minimum value with a further increase in composition ratio of the styrene derivative,
(b-1) an absolute value of the photoelastic coefficient is equal to or smaller than 2×10−12 Pa−1 within a predetermined range of the composition ratio, and
(b-2) an absolute value of an intrinsic birefringence of the optical polymer material is equal to or smaller than 20×10−3 within the predetermined range of the composition ratio, and
(b-3) an absolute value of a temperature coefficient of the intrinsic birefringence is 2×10−5° C.−1 or less, and
(c) the composition ratio of the maleimide derivative is more than the composition ratio of the styrene derivative, and wherein the alternating copolymer comprises (i) from 7 mol % to 27 mol % of the styrene derivative, (ii) from 27 mol % to 68 mol % of the maleimide derivative and (iii) the remainder being at least one monomer of a modified organic compound having a physical property related to mechanical strength, the physical property being different from those of the monomer of the styrene derivative and the monomer of the maleimide derivative.

2 more elements

A low birefringence optical polymer material comprising a polymer made of (i) a monomer of a styrene derivative, (ii) a monomer of at least a maleimide derivative, and (iii) a monomer of a modified organic compound having a physical property related to mechanical strength, the physical property being different from those of the monomer of the styrene derivative and the monomer of the at least one maleimide derivative, wherein

(a) the optical polymer material exhibits a nonlinear property in which, in relation to the monomer of the styrene derivative and the monomer of the maleimide derivative, a photoelastic coefficient of the optical polymer material decreases to a minimum value with an increase in composition ratio of the styrene derivative, and rises above the minimum value with a further increase in composition ratio of the styrene derivative, and a composition ratio of the styrene derivative is within a predetermined range,
(b-1) an absolute value of the photoelastic coefficient is equal to or smaller 2×10−12 Pa−1 value within the predetermined range of the composition ratio,
(b-2) an absolute value of an intrinsic birefringence of the optical polymer material is equal to or smaller than 20×10−3 within the predetermined range of the composition ratio, and
(b-3) an absolute value of a temperature coefficient of the intrinsic birefringence is 2×10−5°°C.−1 or less, and wherein the polymer comprises (i) from 7 mol % to 27 mol % of the styrene derivative, (ii) from 27 mol % to 68 mol % of the maleimide derivative where the maleimide derivative content exceeds that of the styrene derivative and (iii) the remainder being the at least one monomer of a modified organic compound having a physical property related to mechanical strength, the physical property being different from those of the monomer of the styrene derivative and the monomer of the maleimide derivative.

1 more element

Dependencies are inferred from the claim text.