Organic EL display

• US 7,755,262 B2
• Filed: 05/16/2005
• Issued: 07/13/2010
• Est. Priority Date: 05/17/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Choi, Hong Seok
• Primary Examiner(s): Patel; Nimeshkumar D.
• Assistant Examiner(s): Hines; Anne M
• Application Number:
  US11/129,445
• Publication Number:
  US 20050253494A1
• Time in Patent Office: 1,884 Days
• Field of Search: 313112-113, 313310-311, 313498-512
• US Class Current: 313/112
• CPC Class Codes: G02B 27/28 for polarising used in stereoscopes G02B30/25
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

An organic EL display having a polarizing plate is disclosed. The present invention includes an organic EL display panel, a first polarizing plate on the panel to convert a circularly or linearly polarized light to a linearly or circularly polarized light, and a second polarizing plate on the first polarizing plate to have a polarization characteristic of absorbing light in a high light efficiency wavelength range more than light in a low light efficiency wavelength range.

Claims

1. An organic EL display comprising:

an organic EL display panel to have a metal electrode;

a first polarizing plate on the organic EL display panel; and

a second polarizing plate on the first polarizing plate to have a polarization characteristic of absorbing light in a high light efficiency wavelength range more than light in a low light efficiency wavelength range,

wherein the first polarizing plate is converting a linearly polarized light into a circularly polarized or converting a circularly polarized light into a linearly polarized light and

wherein polarization efficiency and transmittance of the second polarizing plate are differently set per a red wavelength, a green wavelength and a blue wavelength, respectively and the second polarizing plate has high transmittance and low polarization efficiency in a blue wavelength rather than the green and red wavelengths.

2. The organic EL display of claim 1, wherein the first polarizing plate is a λ

/4 retarder.

3. The organic EL display of claim 1, wherein the second polarizing plate is a dichroic dye based polarizing plate fabricated by aligning dichroic dye in one direction by extension wherein the dichroic dye has a light absorption characteristic differing according to a light wavelength and a polarized direction.

4. The organic EL display of claim 1, wherein a maximum value of polarization efficiency of the second polarizing plate is tuned to a wavelength corresponding to a maximum value of a visual curve.

5. The organic EL display of claim 1, wherein a maximum value of polarization efficiency of the second polarizing plate is tuned to a wavelength corresponding to a maximum value of an external light.

6. An organic EL display comprising:

a substrate;

an anode on one surface of the substrate;

an organic EL layer on the anode;

a metal cathode on the organic EL layer;

a λ

/4 retarder on the other surface of the substrate; and

a dichroic dye based polarizing plate on the λ

/4 retarder to have a polarization characteristic of absorbing light in a high light efficiency wavelength range more than light in a low light efficiency wavelength range, wherein the dichrioc dye based polarizing plate is fabricated by aligning dichrioc dye in one direction by extension,

wherein the λ

/4 retarder is converting a linearly polarized light from the dichroic dye based polarizing plate into a circularly polarized light to the substrate and converting a circularly polarized light from the substrate into a linearly polarized light to the dichroic dye based polarizing plate and

wherein the dichroic dye based polarizing plate has high transmittance and low polarization efficiency in a blue wavelength rather than the red and green wavelengths.

7. The organic EL display of claim 6, wherein the dichroic dye has a light absorption characteristic differing according to a light wavelength and a polarized direction.

8. The organic EL display of claim 6, wherein a maximum value of polarization efficiency of the dichroic dye based polarizing plate is tuned to a wavelength corresponding to a maximum value of a visual curve.

9. An organic EL display comprising:

an organic EL display panel to have a metal electrode;

a first polarizing plate on the organic EL display panel; and

a second polarizing plate on the first polarizing plate to have a polarization characteristic of absorbing light in a high light efficiency wavelength range more than light in a low light efficiency wavelength range,

wherein the first polarizing plate is converting a linearly polarized light into a circularly polarized or converting a circularly polarized light into a linearly polarized light and

wherein the second polarizing plate has high transmittance and low polarization efficiency in blue and red wavelengths rather than a green wavelength.