Polycarbonate-based oriented film and retardation film

• US 20050163943A1
• Filed: 03/28/2003
• Published: 07/28/2005
• Est. Priority Date: 06/27/2002
• Status: Active Grant

• Current Assignee: Teijin Limited
• Original Assignee: Teijin Limited
• Inventors: Ikeda, Yoshinori, Uchiyama, Akihiko, Ono, Yuhei
• Granted Patent: US 7,223,451 B2
• Time in Patent Office: Days
• US Class Current: 428/1.310
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 2307/516 mono-axially
• CPC Class Codes: B32B 2307/518 bi-axially
• CPC Class Codes: B32B 2369/00 Polycarbonates
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: C08G 64/06 not containing aliphatic unsaturation
• CPC Class Codes: C08J 2369/00 Characterised by the use of polycarbonates; Derivatives of polycarbonates
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: C09K 2323/02 Alignment layer characterised by chemical composition
• CPC Class Codes: C09K 2323/031 Polarizer or dye
• CPC Class Codes: G02B 5/3083 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 Class Codes: Y10T 428/31507 Of polycarbonate

Abstract

A uniaxially or biaxially oriented film which is made from a specific polycarbonate having a fluorene ring and a glass transition temperature of 165° C. or higher and which has a heat shrinkage factor when it is heated at 90° C. for 500 hours of 0.1% or less, and a ratio of retardation R(450) within the film plane at a wavelength of 450 nm to retardation R(550) within the film plane at a wavelength of 550 nm of 1 to 1.06. This film can be used in a high-quality liquid crystal display device such as a vertical alignment liquid crystal display device and is useful as a retardation film which almost solves a frame problem.

Claims

1. A uni- or bi-axially oriented film

(A) which comprises a polymer or polymer mixture containing a recurring unit represented by the following formula (I):

wherein R¹ to R⁸ are each independently a member selected from the group consisting of hydrogen atom, halogen atom, hydrocarbon group having 1 to 6 carbon atoms and hydrocarbon-O-group having 1 to 6 carbon atoms, and X is represented by the following formula (i)-1;

wherein R³⁰ and R³¹ are each independently a halogen atom or alkyl group having 1 to 3 carbon atoms, and n and m are each independently an integer of 0 to 4,

each of the polymer and the polymer mixture containing the recurring unit represented by the above formula (I) in an amount of 30 to 60 mol % based on the total of all the recurring units of the polymer or polymer mixture and having a glass transition temperature of 165°

C. or higher,

(B) which has a heat shrinkage factor when it is heated at 90°

C. for 500 hours under no load of 0.1% or less, and

(C) which satisfies the following formula (1);

1≦

R(450)/R(550)≦

1.06 

 

(1)

wherein R(450) and R(550) are retardations within the film plane at wavelengths of 450 nm and 550 nm, respectively.

2. The film of claim 1, wherein the amount of the recurring unit represented by the formula (I) is larger than 30 mol % based on the total of all the recurring units.

3. The film of claim 1 which is a uniaxially oriented film further satisfying the following expressions (2) and (3) at the same time:

R(550)>

K(550) 

 

(2)
R(550)>

20 nm 

 

(3)

wherein R(550) is as defined in the above expression (1) and K(550) is a value (nm) defined by the following expression (4) at a wavelength of 550 nm;

K=[(n_x+n_y)/2−

n_x]×

d 

 

(4)

wherein n_x, n_y and n_z are refractive indices in x axis, y axis and z axis directions of the film, respectively, and d is the thickness (nm) of the film.

4. The film of claim 1 which is a biaxially oriented film further satisfying the following expression (2′

) and the above expression (3) at the same time;

R(550)≦

K(550) 

 

(2′

)

wherein R(550) and K(550) are as defined in the above expressions.

5. The film of claim 4 which satisfies the following expression (1′

);

1≦

R(450)/R(550)≦

1.05 

 

(1′

)

wherein R(450) and R(550) are as defined in the above expressions.

6. The film of claim 1 which is a biaxially oriented film further satisfying the above expression (2′

), the following expression (3′

) and the following expression (5) at the same time;

R(550)≦

20 nm 

 

(3′

)
K(550)≧

50 nm 

 

(5)

wherein R(550) and K(550) are as defined in the above expressions.

7. The film of claim 1, wherein the polymer or polymer mixture has a glass transition temperature of 200°

C. or higher.

8. The film of claim 1 which is a retardation film.

9. A laminated polarizer film which comprises the film of any one of claims 1 to 6 and a polarizer film in a laminated form.

10. The laminated polarizer film of claim 9 which is laminated in such a manner that the transmission axis of the polarizer film becomes parallel to the slow axis within the plane of the film.

11. A liquid crystal display device comprising the laminated polarizer film of claim 9 or 10.

12. The liquid crystal display device of claim 11 which is in a vertical alignment mode.