Retardation plate and its manufacturing method, circularly polarizing plate and 1/2 wave plate using same, and a reflective liquid crystal display

• US 20040041968A1
• Filed: 08/29/2003
• Published: 03/04/2004
• Est. Priority Date: 08/30/2002
• Status: Abandoned Application

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Ueda, Tadashi, Sato, Takanori, Otoshi, Masaaki, Terai, Fumitaka
• Application Number:
  US10/650,824
• Publication Number:
  US 20040041968A1
• Time in Patent Office: Days
• US Class Current: 349/117
• 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

Abstract

A method is provided for manufacturing a wide band retardation plate which gives uniform phase difference characteristics to incident light over the whole visible wavelength region, and which, as it permits selection of raw materials regardless of whether they have a positive or negative intrinsic double refraction value, allows a wide selection of raw materials. For this purpose, the method comprises a machine direction-stretched film-forming step for transporting and stretching in an identical direction to the transport direction, a Material A of two or more materials having different positive intrinsic double refraction values to form a machine direction-stretched film, a transverse direction-stretched film-forming step for transporting and stretching in a perpendicular direction to the transport direction, a Material B of the aforesaid two or more materials to form a transverse direction-stretched film, and a lamination step for laminating the machine direction-stretched film and the transverse direction-stretched film.

Claims

1. A retardation plate comprising:

a laminate of two or more materials having different intrinsic double refraction values, wherein the retardation plate satisfies the relation;

Re(450)<

Re(550)<

Re(650),

where Re(450), Re(550) and Re(650) are retardation values in wavelengths 450 nm, 550 nm and 650 nm, respectively.

2. A retardation plate according to claim 1, wherein the intrinsic double refraction values of two or more materials are positive, and the slow axes of each layer are mutually perpendicular.

3. A retardation plate according to claim 1, wherein the intrinsic double refraction values of two or more materials are negative, and the slow axes of each layer are mutually perpendicular.

4. A retardation plate according to claim 1, wherein the intrinsic double refraction values of two or more materials are positive and negative, and the slow axes of each layer are mutually perpendicular.

5. A retardation plate according to claim 1, wherein the orientation axes of the molecular chains in each layer are mutually perpendicular.

6. A retardation plate according to claim 1, wherein the orientation axes of the molecular chains in each layer are mutually parallel.

7. A retardation plate according to claim 1, wherein the retardation plate further comprises an adhesive layer.

8. A retardation plate according to claim 1, wherein at least one of the materials in each layer is a norbornene polymer.

9. A retardation plate according to claim 1, wherein at least one of the materials is selected from at least one of a polyester polymer, polyarylene sulfide polymer, polyarylate polymer and polycarbonate polymer.

10. A retardation plate according to claim 1, comprising two layers wherein, when the absolute values of the retardation (Re) at a wavelength of 450 nm and a wavelength of 550 nm are respectively Re(450) and Re(550), the difference in the value of Re(450)/Re(550) of each layer is 0.03 or more.

11. A retardation plate according to claim 1, comprising two layers wherein, when the absolute value of the retardation (Re) at a wavelength of 450 nm and a wavelength of 550 nm are respectively Re(450) and Re(550), the value of Re(450)/Re(550) in each layer is mutually different, and the value of Re(550) in the layer having the smaller value of Re(450)/Re(550) is larger than the value of Re(550) in the layer having the larger value of Re(450)/Re(550).

12. A retardation plate according to claim 1, wherein, at wavelengths of λ

=450 nm, 550 nm and 650 nm, the retardation Re(λ

) and the wavelength λ

satisfy the following relation;

0.2≦

Re(λ

)/λ

≦

0.3

13. A retardation plate according to claim 1, wherein, at wavelengths of λ

=450 nm, 550 nm and 650 nm, the retardation Re(λ

) and the wavelength λ

satisfy the following relation;

0.4≦

Re(λ

)/λ

≦

0.6

14. A retardation plate according to claim 1, wherein the intrinsic double refraction values of the two or more materials are positive,

a Material A of the two or more materials is transported and stretched in an identical direction to the transport direction to form a machine direction-stretched film, and

a Material B of the two or more materials is transported and stretched in a perpendicular direction to the transport direction to form a transverse direction-stretched film.

15. A retardation plate according to claim 1, wherein the intrinsic double refraction values of the two or more materials are negative,

a Material C of the two or more materials is transported and stretched in an identical direction to the transport direction to form a machine direction-stretched film, and

a Material D of the two or more materials is transported and stretched in a perpendicular direction to the transport direction to form a transverse direction-stretched film.

16. A retardation plate according to claim 1, wherein the intrinsic double refraction values of the two or more materials are positive and negative, and the materials of the two or more materials are transported and stretched in one of an identical direction and a perpendicular direction to the transport direction to form a machine direction-stretched film and a transverse direction-stretched film.

17. A ½

wave plate comprising;

a laminate of a polarizing plate, and a retardation plate wherein, at λ

=450 nm, 550 nm and 650 nm, the retardation Re(λ

) and the wavelength λ

satisfy the relation;

0.4≦

Re(λ

)/λ

≦

0.6,

and the polarizing plate transmission axis of the polarizing plate and the slow axis of the retardation plate intersect each other.

18. A ½

wave plate according to claim 17, wherein the polarizing plate transmission axis of the polarizing plate and the slow axis of the retardation plate intersect each other at an angle of 30°

to 60°

.

19. A circularly polarizing plate comprising:

a laminate of a polarizing plate, and a retardation plate wherein, at λ

=450 nm, 550 nm and 650 nm, the retardation Re(λ

) and the wavelength λ

satisfy the relation;

0.2≦

Re(λ

)/λ

≦

0.3,

and the polarizing plate transmission axis of the polarizing plate and the slow axis of the retardation plate intersect each other.

20. A circularly polarizing plate according to claim 19, wherein the polarizing plate transmission axis of the polarizing plate and the slow axis of the retardation plate intersect each other at an angle of 30°

to 60°

.

21. A reflective liquid crystal display comprising:

a laminate of a reflector,a liquid crystal cell, and a polarizing plate laminated in this sequence,and

a retardation plate formed by laminating two or more materials having different intrinsic double refraction values between the reflector and the polarizing plate,

wherein the retardation plate satisfies the relation;

Re(450)<

Re(550)<

Re(650),

where Re(450), Re(550) and Re(650) are retardation values in wavelengths 450 nm, 550 nm and 650 nm,respectively.

22. A method of manufacturing a retardation plate comprising the steps of:

transporting and stretching in an identical direction to the transport direction a Material A to form a machine direction-stretched film,

transporting and stretching in a perpendicular direction to the transport direction a Material B to form a transverse direction-stretched film, and

laminating the machine direction-stretched film and the transverse direction-stretched film,

wherein the Material A and B have different positive intrinsic double refraction values, and the retardation plate comprises;

a laminate of two or more materials having different intrinsic double refraction values, wherein the retardation plate satisfies the relation;

Re(450)<

Re(550)<

Re(650),

where Re(450), Re(550) and Re(650) are retardation values in wavelengths 450 nm, 550 nm and 650 nm, respectively.

23. A method of manufacturing a retardation plate according to claim 22,

wherein the step of laminating is one of (1) a lamination step performed by transporting stretched films together in an identical direction, (2) a lamination step performed by sticking wherein the slow axes in the stretched films are arranged to be perpendicular, and (3) a lamination step performed by sticking using an adhesive.

24. A method of manufacturing a retardation plate according to claim 22,

wherein the step of forming the machine direction-stretched film,the step of forming the transverse direction-stretched film, and the step of laminating, are performed continuously.

25. A method of manufacturing a retardation plate comprising the steps of:

transporting and stretching in an identical direction to the transport direction a Material C to form a machine direction-stretched film,

transporting and stretching in a perpendicular direction to the transport direction a Material D to form a transverse direction-stretched film, and

laminating the machine direction-stretched film and the transverse direction-stretched film,

wherein the Material C and D have different positive intrinsic double refraction values, and the retardation plate comprises;

a laminate of two or more materials having different intrinsic double refraction values, wherein the retardation plate satisfies the relation;

Re(450)<

Re(550)<

Re(650),

where Re(450), Re(550) and Re(650) are retardation values in wavelengths 450 nm, 550 nm and 650 nm, respectively.

26. A method of manufacturing a retardation plate according to claim 25,

wherein the step of laminating is one of (1) a lamination step performed by transporting stretched films together in an identical direction, (2) a lamination step performed by sticking wherein the slow axes in the stretched films are arranged to be perpendicular, and (3) a lamination step performed by sticking using an adhesive.

27. A method of manufacturing a retardation plate according to claim 25,

wherein the step of forming the machine direction-stretched film,the step of forming the transverse direction-stretched film, and the step of laminating, are performed continuously.

28. A method of manufacturing a retardation plate comprising the steps of:

transporting and stretching in one of an identical direction and a perpendicular direction to the transport direction, two or more materials having positive and negative intrinsic double refraction values to form one of a machine direction-stretched film and a transverse direction-stretched film, and

laminating the stretched films,

wherein the retardation plate comprises;

a laminate of two or more materials having different intrinsic double refraction values, wherein the retardation plate satisfies the relation Re(450)<

Re(550)<

Re(650),

where Re(450), Re(550) and Re(650) are retardation values in wavelengths 450 nm, 550 nm and 650 nm, respectively.

29. A method of manufacturing a retardation plate according to claim 28,

wherein the step of laminating is one of (1) a lamination step performed by transporting stretched films together in an identical direction, (2) a lamination step performed by sticking wherein the slow axes in the stretched films are arranged to be perpendicular, and (3) a lamination step performed by sticking using an adhesive.

30. A method of manufacturing a retardation plate according to claim 28,

wherein the step of forming the stretched film, and the step of laminating, are performed continuously.