Optical film, circularly polarizing plate, and image display device

Patent metadata

Field	Value
Publication number	US-9500790-B2
Application number	US-201314379994-A
Country	US
Kind code	B2
Filing date	Feb 19, 2013
Priority date	Feb 22, 2012
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A optical film includes a thermoplastic resin and a compound wherein: (1) the absorption spectrum of said compound in solution has at least two absorption maxima in the 200-350 nm wavelength range; (2) letting λmax1 represent the wavelength of a first absorption maximum (one of the aforementioned absorption maxima) and letting λmax2 represent the wavelength of a second absorption maximum (another of the aforementioned absorption maxima) at a shorter wavelength than the first absorption maximum, (λmax1−λmax2) is at least 20 nm; (3) the aspect ratio of the molecules of the compound is at least 1.70; (4) each molecule of the compound has a non-aromatic hydrocarbon ring, a non-aromatic heterocycle, or an aromatic heterocycle; (5) the in-plane-retardation increase sensitivity of the compound is at least 0.1; 110 nm≦R 0 (550)≦170 nm; 0.72≦R 0 (450)/R 0 (550)≦0.96; and 0.83≦R 0 (550)/R 0 (650)≦0.97.

First claim

The invention claimed is:

1. An optical film comprising a thermoplastic resin and at least one compound which satisfies all of the following requirements (1) to (5):
(1) the compound has at least two absorption maxima in a wavelength region of from 200 nm to 350 nm in a solution absorption spectrum;
(2) when a wavelength of a first absorption maximum of the two absorption maxima in the wavelength region of from 200 nm to 350 nm is designated as λmax1, and a wavelength of a second absorption maximum of the two absorption maxima at shorter wavelengths than the first absorption maximum is designated as λmax2, wherein λmax1−λmax2 is 20 nm or more;
(3) an aspect ratio of a molecule of the compound is 1.70 or more;
(4) the compound has a non-aromatic hydrocarbon ring, an aromatic heterocyclic ring, or a non-aromatic heterocyclic ring in the molecule; and
(5) for a sample film having a thickness of 60 μm and containing the thermoplastic resin and the compound at a proportion of 1% by mass with respect to the thermoplastic resin, when a retardation in an in-plane direction at a wavelength of 550 nm before stretching of the sample film is designated as R 0 A0(550), and a retardation in the in-plane direction at a wavelength of 550 nm after stretching at a temperature higher by 25° C. than a glass transition temperature of the sample film is designated as R 0 A1(550), so that a in-plane retardation sensitivity obtained by dividing R 0 A1(550)−R 0 A0(550) by actual stretch ratio of the sample film is designated as A; and
for a blank film having a thickness of 60 μm and formed from the thermoplastic resin, when a retardation in the in-plane direction at a wavelength of 550 nm before stretching of the blank film is designated as R 0 B0(550), and a retardation in the in-plane direction at a wavelength of 550 nm after stretching at a temperature higher by 25° C. than a glass transition temperature of the blank film is designated as R 0 B1(550), so that an in-plane retardation sensitivity obtained by dividing R 0 B1(550)−R 0 B0(550) by actual stretch ratio of the blank film is designated as B,
an in-plane retardation increase sensitivity defined by A−B is 0.1 or more,
wherein when the retardations in the in-plane direction measured at wavelengths of 450 nm, 550 nm and 650 nm are designated as R 0 (450), R 0 (550) and R 0 (650), respectively, the following Formulas (a) to (c) are all satisfied:
110 nm≦ R 0 (550)≦170 nm;  (a)

0.72 ≦R 0 (450)/ R 0 (550)≦0.96; and  (b)

0.83 ≦R 0 (550)/ R 0 (650)≦0.97.  (c)

2. The optical film according to claim 1 , wherein the thermoplastic resin includes a cellulose derivative.

3. The optical film according to claim 1 , wherein the compound has at least one non-aromatic ring in the molecule.

4. The optical film according to claim 1 , wherein a value of λmax1−λmax2 of the compound is 50 nm or more.

5. The optical film according to claim 1 , wherein when a refractive index in an in-plane slow axis direction of the optical film is designated as nx, a refractive index in a direction perpendicular to the slow axis in the plane of the optical film is designated as ny, and a refractive index in a thickness direction (Rth) of the optical film is designated as nz, the relationship of the following Formula (d) is further satisfied:
0≦ Nz=Rth (550)/ R 0 (550)+0.5≦1.  (d)

6. The optical film according to claim 1 , wherein the compound is represented by the following Formula (A):

wherein in Formula (A),
Q represents an aromatic hydrocarbon ring, a non-aromatic hydrocarbon ring, an aromatic heterocyclic ring, or a non-aromatic heterocyclic ring;
W a and W b each represent a hydrogen atom or a substituent, W a and W b each being bonded to an atom that constitutes the ring of Q, the atom to which W a is bonded being adjacent to the atom to which W b is bonded, W a and W b being different from each other, and W a and W b may be bonded to each other to form a ring;
R 3 represents a substituent;
m is an integer from 0 to 2;
when m is 2, R 3 's are identical or different;
n represents an integer from 1 to 10; when n is 2 or more, a plurality of Q's, L 2 's, W a 's, W b 's, R 3 's, and m's are identical or different from each other;
L 1 and L 2 each independently represent a single bond, or at least one divalent linking group selected from the group consisting of an alkylene group, an alkenylene group, an alkynylene group, —O—, —(C═O)—, —(C═O)—O—, —NR L —, —S—, —(O═S═O)— and —(C═O)—NR L —;
R L represents a hydrogen atom or a substituent; and
R 1 and R 2 each independently represent a substituent.

7. The optical film according to claim 6 , wherein the compound represented by Formula (A) is a compound represented by the following Formula (B):

wherein in Formula (B),
W a and W b each represent a hydrogen atom or a substituent, W a and W b being different from each other, and W a and W b may be bonded to each other to form a ring;
R 3 represents a substituent;
m is an integer from 0 to 2;
when m is 2, R 3 's are identical or different;
L 1 and L 2 each independently represent a single bond, or at least one divalent linking group selected from the group consisting of an alkylene group, an alkenylene group, an alkynylene group, —O—, —(C═O)—, —(C═O)—O—, —NR L —, —S—, —(O═S═O)— and —(C═O)—NR L —;
R L represents a hydrogen atom or a substituent; and
R 1 and R 2 each independently represent a substituent.

8. The optical film according to claim 7 , wherein the compound represented by Formula (B) is a compound represented by the following Formula (1B):

wherein in Formula (1B),
W a and W b each represent a hydrogen atom or a substituent, W a and W b being different from each other, and W a and W b may be bonded to each other and form a ring;
R 3 represents a substituent;
m is an integer from 0 to 2;
when m is 2, R 3 's may bee are identical or different;
L 1 and L 2 each independently represent a single bond, or at least one divalent linking group selected from the group consisting of an alkylene group, an alkenylene group, an alkynylene group, —O—, —(C═O)—, —(C═O)—O—, —NR L —, —S—, —(O═S═O)— and —(C═O)—NR L —;
R L represents a hydrogen atom or a substituent; and
R 1 and R 2 each independently represent a substituent.

9. The optical film according to claim 7 , wherein the compound represented by Formula (B) is represented by the following Formula (2B):

wherein in Formula (2B),
W 1 represents a cyclic group, and among the ring-constituting atoms of W 1 , the atom that is bonded to the benzene ring is a carbon atom or a nitrogen atom;
R 3 represents a substituent;
m is an integer from 0 to 2;
when m is 2, R 3 's are identical or different;
L 1 and L 2 each independently represent a single bond, or at least one divalent linking group selected from the group consisting of an alkylene group, an alkenylene group, an alkynylene group, —O—, —(C═O)—, —(C═O)—O—, —NR L —, —S—, —(O═S═O)— and —(C═O)—N L —;
R L represents a hydrogen atom or a substituent; and
R 1 and R 2 each independently represent a substituent.

10. The optical film according to claim 1 , wherein a thickness of the optical film is 10 μm to 100 μm.

11. The optical film according to claim

Assignees

• Konica Minolta Inc

Inventors

• Fujisawa Rie
• Kogure Midori
• Suzuki Takatugu

Classifications

• C07D207/452

  with hydrocarbon radicals, substituted by hetero atoms, directly attached to the ring nitrogen atom · CPC title

• C07D209/86

  with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to carbon atoms of the ring system · CPC title

• G02B5/3083 Primary

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• G02B1/111

  using layers comprising organic materials · CPC title

• C07D307/60

  Two oxygen atoms, e.g. succinic anhydride · CPC title