Polarizing plate for organic light-emitting display and display device including the same

• US 9,081,144 B2
• Filed: 12/07/2012
• Issued: 07/14/2015
• Est. Priority Date: 12/12/2011
• Status: Active Grant

• Current Assignee: Cheil Industries Incorporated
• Original Assignee: Cheil Industries Incorporated
• Inventors: Kim, Do Won, Kim, Ran, Kim, Jin Sook, Cho, Hyeon, Shin, Jik Soo
• Primary Examiner(s): FONT, FRANK G
• Application Number:
  US13/708,550
• Publication Number:
  US 20130163081A1
• Time in Patent Office: 949 Days
• Field of Search: 359/485.03, 359/487.02
• US Class Current: 1/1
• CPC Class Codes: G02B 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/875 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/8793 Arrangements for polarized light emission H10K59/8791 takes precedence

Abstract

A polarizing plate for use with an organic light emitting display includes an adhesive layer, a retardation film, a polarizer, and a protective film sequentially stacked in this order, the polarizing plate further including a positive C plate.

Claims

1. A polarizing plate for an organic light-emitting display, the polarizing plate comprising:

a stack sequentially including an adhesive layer, a retardation film, a polarizer, and a protective film sequentially; and

a positive C plate in contact with the retardation film, wherein a sum of in-thickness retardations of the retardation film and the positive C plate lies within a range to compensate for the in-thickness retardation of the retardation film.

2. The polarizing plate as claimed in claim 1, wherein the positive C plate is interposed between the polarizer and the retardation film.

3. The polarizing plate as claimed in claim 1, wherein the positive C plate is interposed between the retardation film and the adhesive layer.

4. The polarizing plate as claimed in claim 1, wherein the positive C plate has an in-thickness retardation (Rth) of about −

130 nm to about −

50 nm at a wavelength of 550 nm, Rth being calculated according to the following Equation

Rth=((nx+ny)/2−

nz)×

d,

where nx, ny, and nz are indexes of refraction in x-, y- and z-axis directions of the positive C plate, respectively, and d is a thickness of the positive C plate.

5. The polarizing plate according as claimed in claim 1, wherein the positive C plate has an in-plane retardation (Re) of about 0 nm to about 5 nm at a wavelength of 550 nm, Re being calculated according to the following

Re=(nx−

ny)×

d,

where nx, and ny are indexes of refraction in x- and y-axis directions of the positive C plate, respectively, and d is a thickness of the positive C plate.

6. The polarizing plate as claimed in claim 1, wherein the positive C plate has a thickness of about 0.5 μ

m to about 20 μ

m.

7. The polarizing plate as claimed in claim 1, wherein the retardation film has an in-thickness retardation (Rth) of about 50 nm to about 150 nm at a wavelength of 550 nm.

8. The polarizing plate as claimed in claim 1, wherein the retardation film has an in-plane retardation (Re) of about 100 nm to about 150 nm at a wavelength of 550 nm.

9. The polarizing plate as claimed in claim 1, wherein the retardation film has a degree of biaxiality Nz that ranges from about 0 to about 2 at a wavelength of 550 nm, Nz being calculated according to the following

Nz=(nx−

nz)/(nx−

ny),

where nx, ny, and nz are indexes of refraction in x-, y-, and z-axis directions of the retardation film, respectively.

10. The polarizing plate as claimed in claim 1, wherein a sum of the in-thickness retardations of the retardation film and the positive C plate ranges from about −

30 nm to about 30 nm at a wavelength of 550 nm.

11. The polarizing plate according as claimed in claim 1, further comprising at least one functional film, the at least one functional film being at least one of low reflectivity films, anti-glare films, low reflectivity and anti-glare hybrid films, or hard coating films.

12. The polarizing plate according as claimed in claim 11, wherein the at least one functional film is stacked on the protective film.

13. The polarizing plate as claimed in claim 1, wherein the adhesive layer comprises an adhesive resin and a dye.

14. The polarizing plate as claimed in claim 13, wherein the dye has an absorption wavelength of about 380 nm to about 430 nm.

15. An optical display device, comprising:

a display panel; and

a polarizing plate, the polarizing plate including;

a stack sequentially including an adhesive layer, a retardation film, a polarizer, and a protective film sequentially, the adhesive layer facing a light emitting surface of the display panel; and

a positive C plate in contact with the retardation film, wherein a sum of in-thickness retardations of the retardation film and the positive C plate lies within a range to compensate for the in-thickness retardation of the retardation film.

16. An optical display device as claimed in claim 15, wherein the display panel is an organic light-emitting display panel.