ORGANIC EL DISPLAY DEVICE AND MANUFACTURING METHOD THEREOF

• US 20100084676A1
• Filed: 10/07/2009
• Published: 04/08/2010
• Est. Priority Date: 10/08/2008
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: TANAKA, Masahiro
• Granted Patent: US 8,093,612 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C23C 14/048 using irradiation by energy or particles
• 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
• CPC Class Codes: H10K 71/18 using non-liquid printing techniques, e.g. thermal transfer printing from a donor sheet

Abstract

An organic EL display device forms an organic EL layer on a pixel portion by a transfer method without using a sophisticated optical system. A patterned light reflection layer is formed on a donor substrate. A light absorption layer is formed on the light reflection layer. An organic EL material layer is formed on the light absorption layer. An element substrate on which banks, lower electrodes and the like are formed is arranged to face a donor substrate in an opposed manner. When light is radiated to the donor substrate from a flash lamp or the like, only portions of the optical absorption layer where the light reflection layers are not formed are heated, and such portions of the organic EL material layer are evaporated and applied to a lower electrode formed on the element substrate. Due to such steps, the organic EL layer can be formed by a transfer method without using a sophisticated optical system.

Claims

1. An organic EL display device having pixels each of which is formed by stacking a lower electrode, an organic EL layer and an upper electrode in such order in a region surrounded by a bank, wherein

assuming a thickness of the organic EL layer stacked on the lower electrode as “

a” and

a thickness of an organic EL layer stacked on a side wall of the bank as “

b”

, a region which satisfies a relationship of 0.9a≦

b is defined on the side wall of the bank.

2. An organic EL display device according to claim 1, wherein the region which satisfies the relationship of 0.9a≦

b is defined at a portion of the side wall of the bank closer to the lower electrode and having a height less than half of a height of the bank.

3. An organic EL display device having pixels each of which is formed by stacking a lower electrode, an organic EL layer and an upper electrode in such order in a region surrounded by a bank, wherein

assuming a maximum thickness out of a thickness of the organic EL layer stacked on the lower electrode as “

a” and

a maximum thickness out of a thickness of an organic EL layer stacked on a side wall of the bank as “

b”

, a region which satisfies a relationship of 0.9a≦

b is defined on the side wall of the bank.

4. An organic EL display device according to claim 3, wherein the region which satisfies the relationship of 0.9a≦

b is defined at a portion of the side wall of the bank closer to the lower electrode and having a height less than half of a height of the bank.

5. An organic EL display device having pixels each of which is formed by stacking a lower electrode, an organic EL layer and an upper electrode in such order in a region surrounded by a bank, wherein

a taper angle made by the bank and the lower electrode is set to not less than 60°

, and

assuming a thickness of the organic EL layer stacked on the lower electrode as “

a” and

a thickness of an organic EL layer stacked on a side wall of the bank as “

b”

, a region which satisfies a relationship of 0.9a≦

b is defined on the side wall of the bank.

6. A manufacturing method of an organic EL display device which includes a TFT substrate on which pixels each of which is formed by stacking a lower electrode, an organic EL layer and an upper electrode in such order are formed in a matrix array, the manufacturing method comprising the steps of:

arranging a donor substrate which is formed by forming a patterned light reflection layer on a substrate, forming a light absorption layer on the light reflection layer and forming an organic EL material layer on the light absorption layer in a state that the donor substrate faces the TFT substrate in an opposed manner; and

forming an organic EL layer on said each pixel which is formed on the TFT substrate by radiating light to the donor substrate thus evaporating the organic EL material layer.

7. A manufacturing method of an organic EL display device according to claim 6, wherein the organic EL layer is formed of a plurality of layers, and out of the organic EL layer, a light emission layer and an electron transport layer are formed by evaporating an organic EL material layer for forming the light emitting layer, and the electron transport layer is formed by evaporating an organic EL material layer for forming the electron transport layer.

8. A manufacturing method of an organic EL display device according to claim 7, wherein out of the organic EL layer, a hole transport layer is formed by evaporating an organic EL material layer for forming the hole transport layer.

9. A manufacturing method of an organic EL display device according to claim 6, wherein the light is a light from a flash lamp.

10. A manufacturing method of an organic EL display device according to claim 6, wherein a surface protective film is formed on the light absorption layer.

11. A manufacturing method of an organic EL display device which includes a TFT substrate on which pixels each of which is formed by stacking a lower electrode, an organic EL layer and an upper electrode in a region surrounded by a bank in such order are formed in a matrix array, the manufacturing method comprising the steps of:

arranging a donor substrate which is formed by forming a patterned light absorption layer on the substrate, by forming light reflection layers on the light absorption layer, and by forming an organic EL material layer on the light reflection layer in a state that the donor substrate faces the TFT substrate in an opposed manner; and

forming an organic EL layer on said each pixel which is formed on the TFT substrate by radiating light to the donor substrate thus evaporating the organic EL material layer.

12. A manufacturing method of an organic EL display device according to claim 11, wherein the organic EL layer is formed of a plurality of layers, and out of the organic EL layer, a light emission layer and an electron transport layer are formed by evaporating an organic EL material layer for forming the light emitting layer, and the electron transport layer is formed by evaporating an organic EL material layer for forming the electron transport layer.

13. A manufacturing method of an organic EL display device according to claim 12, wherein out of the organic EL layer, a hole transport layer is formed by evaporating an organic EL material layer for forming the hole transport layer.

14. A manufacturing method of an organic EL display device according to claim 11, wherein the light is a light from a flash lamp.

15. A manufacturing method of an organic EL display device according to claim 11, wherein a surface protective film is formed on the light reflection layer.