TRANSPARENT ORGANIC LIGHT EMITTING DISPLAY DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20140183472A1
• Filed: 12/03/2013
• Published: 07/03/2014
• Est. Priority Date: 12/27/2012
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: KIM, YongChul, IM, Jonghyeok
• Granted Patent: US 9,349,780 B2
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: H10K 2102/3031 Two-side emission, e.g. transparent OLEDs [TOLED]
• CPC Class Codes: H10K 59/121 characterised by the geometry or disposition of pixel elements
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]

Abstract

A transparent organic light emitting display device and a method of manufacturing the transparent organic light emitting display device are provided. The transparent organic light emitting display device comprises a plurality of sub pixel regions, each having a emissive area and a transmissive area, a thin film transistor disposed in the emissive area, and an organic light emitting element electrically connected to the thin film transistor. While the emissive area emits light to display image on the display device, the transmissive area allows the external light to be passed through the display device so that objects behind the display device can be viewed simultaneously with the displayed image.

Claims

1. A transparent organic light emitting display device comprising:

a first substrate having a sub pixel region with an emissive area and a transmissive area;

a thin film transistor (TFT) disposed in the emissive area;

an organic light emitting element disposed in the emissive area, the organic light emitting element being electrically connected to the TFT disposed in the emissive area; and

a plurality of insulating layers in the emissive area, wherein at least one of the plurality of insulating layers is extended into the transmissive area and at least a part of the insulating layer being extended into the transmissive area has substantially the same refractive index as the first substrate.

2. The transparent organic light emitting display device of claim 1, wherein said at least one of the plurality of insulating layers being extended into the transmissive area is any one of a gate insulating layer, an interlayer insulating layer, a passivation layer, an overcoating layer and a buffer layer.

3. The transparent organic light emitting display device of claim 1, wherein said at least one of the plurality of insulating layers being extended into the transmissive area has a multilayered structure, and wherein the multilayered structure includes at least one layer contained within the emissive area and at least one layer extended into the transmissive area.

4. The transparent organic light emitting display device of claim 3, wherein said at least one insulating layer being extended into the transmissive area is interposed between the TFT and the first substrate.

5. The transparent organic light emitting display device of claim 4, wherein the TFT disposed on the substrate is a coplanar TFT with an oxide semiconductor layer, and wherein a layer of the multilayered structure in contact with the oxide semiconductor layer is extended into the transmissive area from the emissive area and does not include silicon nitride.

6. The transparent organic light emitting display device of claim 3, wherein the TFT disposed on the substrate is an inverted-staggered TFT having an oxide semiconductor layer disposed on a gate electrode, said multilayered structure being interposed between the gate electrode and the oxide semiconductor layer, and wherein a layer of the multilayered structure in contact with the oxide semiconductor layer is extended into the transmissive area and does not include silicon nitride.

7. The transparent organic light emitting display device of claim 3, further comprising a second substrate, wherein the first substrate, said at least one layer of the multilayered structure extended into the transmissive area and the second substrate all have substantially the same refractive index with respect to each other.

8. The transparent organic light emitting display device of claim 3, further comprising an encapsulating layer covering the organic light emitting element, said encapsulating layer being disposed on at least part of the emissive area and at least part of the transmissive area, wherein the first substrate, the encapsulating layer and said at least one layer of the multilayered structure extended into the transmissive area have substantially the same refractive index.

9. The transparent organic light emitting display device of claim 8, wherein the organic light emitting element comprises an anode, an organic light emitting layer configured to emit white light, and a cathode, and wherein the organic light emitting display device further comprises a color filter for filtering the white light to form colored light.

10. A transparent organic light emitting display device comprising:

a substrate having a plurality of sub pixel regions, each of the plurality of sub pixel regions having an emissive area and a transmissive area;

a first insulating layer on the substrate;

a thin film transistor (TFT) disposed on the first insulating layer, the TFT having a gate electrode, a second insulating layer, a source electrode, a drain electrode and an active layer;

a third insulating layer disposed on the TFT;

an organic light emitting element disposed on the second insulating layer; and

an encapsulation layer disposed on the organic light emitting element,

wherein at least one of the first, second and third insulating layers has a refractive index that differs from a refractive index of the substrate by more than a predetermined value, and contained within the emissive area of the sub pixel region.

11. The transparent organic light emitting display device of claim 10, wherein at least one of the first, second and third insulating layers has a refractive index that is substantially the same as that of the substrate, and is extended into the transmissive area from the emissive area of the sub pixel region.

12. The transparent organic light emitting display device of claim 10, wherein at least one of the first, second and third insulating layers is a multilayered structure including at least one layer that has substantially the same refractive index as the substrate and at least one layer with a refractive index differing from the substrate by more than the predetermined threshold value, and wherein said at least one layer with the different refractive index from the substrate is contained within the emissive area of the sub pixel region.

13. The transparent organic light emitting display device of claim 10, wherein the third insulating layer has a refractive index substantially the same as that of the substrate, and is extended into the transmissive area from the emissive area of the sub pixel region.

14. The transparent organic light emitting display device of claim 13, wherein the third insulating layer is one of an overcoating layer and a passivation layer.

15. The transparent organic light emitting display device of claim 11, wherein a refractive index of the encapsulating layer differs from that of the substrate and that of the insulating layer being extended into the transmissive area by less than a predetermined value.

16. A method of manufacturing a transparent organic light emitting display device having sub pixel with a emissive area and a transmissive area, the method comprising:

forming a buffer layer on a first substrate;

forming an active layer on the buffer layer;

forming a gate insulating layer on the active layer;

forming a plurality of electrodes on the active layer, the plurality of electrodes including a source electrode, a drain electrode, and a gate electrode electrically insulated from each other by an interlayer insulating layer;

forming an overcoating layer over the emissive area and the transmissive area of the transparent organic light emitting display device; and

forming an organic light emitting element on the overcoating layer in the emissive area.

17. The method of claim 16, wherein the step for forming the buffer layer comprises:

forming a first buffer layer in the emissive area; and

forming a second buffer layer contacting the active layer in the emissive area and the transmissive area, wherein the first buffer layer includes silicon nitride and the second buffer layer includes silicon oxide.

18. The method of claim 16, wherein the gate insulating layer is formed to extend into the transmissive area from the emissive area of each sub pixel, and wherein the gate insulating layer is formed of a material with substantially the same refractive index as the substrate.

19. The method of claim 16, wherein the interlayer insulating layer is formed to extend into the transmissive area from the emissive area of each sub pixel, and wherein the interlayer insulating layer is formed of a material with substantially the same refractive index as the substrate.

20. The method of claim 16, the method further comprises forming a color filter on the organic light emitting element, wherein the organic light emitting element is configured to emit white light.

21. The method of claim 16, wherein the step of forming the organic light emitting element comprises:

forming a reflection layer on the part of the overcoating layer disposed in the emissive area;

forming a transparent conductive layer on the overcoating layer;

forming an organic light emitting layer on the transparent conductive layer; and

forming a cathode on the organic light emitting layer, wherein the organic light emitting layer is disposed in the emissive area and the transmissive area.