Electroluminescence display apparatus with opening in silicon oxide layer

• US 6,850,005 B2
• Filed: 07/24/2003
• Issued: 02/01/2005
• Est. Priority Date: 07/25/2002
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Nishikawa, Ryuji, Ichikawa, Shinji, Suzuki, Koji, Yoneda, Kiyoshi
• Primary Examiner(s): Williams, Joseph
• Assistant Examiner(s): QUARTERMAN, KEVIN J
• Application Number:
  US10/627,179
• Publication Number:
  US 20040066136A1
• Time in Patent Office: 558 Days
• Field of Search: 313/498, 313/499, 313/500, 313/506, 257/59, 257/40, 257/72, 257/79, 345/76, 345/80, 345/92
• US Class Current: 313/506
• CPC Class Codes: H10K 50/84 Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/865 comprising light absorbing layers, e.g. light-blocking layers
• 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 59/87 Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 59/878 comprising reflective means
• CPC Class Codes: H10K 59/8792 comprising light absorbing layers, e.g. black layers

Abstract

An inter-layer insulating film and a gate insulating film which are positioned on the optical path of light from an organic EL element to be externally emitted, for example, located under a transparent electrode, are removed. Because SiO₂ films having a refractive index which differs significantly from refractive indexes of other films are used for these films, there was a problem of light attenuation in these layers. Such light attenuation can be reduced by removing these layers located in the region through which light from the organic EL element passes.

Claims

1. An electroluminescence display apparatus comprising a plurality of pixels provided over a common substrate, each pixel comprising:

an electroluminescence element including a transparent lower electrode, an emissive element layer including an emissive material, and an upper electrode formed to face the lower electrode via the emissive element layer; and

a thin film transistor for controlling light emission of the electroluminescence element, the thin film transistor being formed below the electroluminescence element and electrically connected with the electroluminescence element, wherein

the thin film transistor includes a gate electrode, a silicon oxide layer, and a silicon active layer,

the lower electrode of the electroluminescence element which is connected to the thin film transistor extends in a region where the thin film transistor is not formed, and

in the region where the thin film transistor is not formed, the silicon oxide layer has an opening, and a moisture blocking insulating film, which is formed to cover the thin film transistor in a region where the thin film transistor is formed and which is formed over the substrate where the silicon oxide layer is removed in the region where the thin film transistor is not formed, and a planarization insulating film which is formed on the moisture blocking insulating film, are provided between the lower electrode and the substrate.

2. An electroluminescence display apparatus according to claim 1, wherein

the moisture blocking insulating film includes silicon nitride.

3. An electroluminescence display apparatus according to claim 1, wherein

an inter-layer insulating film including a silicon oxide layer is formed between the thin film transistor and the moisture blocking insulating film which covers the thin film transistor,

a gate insulating film including a silicon oxide layer is formed between the silicon active layer and the gate electrode of the thin film transistor, and

both the silicon oxide layer of the inter-layer insulating film and the silicon oxide layer of the gate insulating film have an opening in the region where the thin film transistor is not formed.

4. An electroluminescence display apparatus according to claim 3, wherein

a buffer layer is formed between the substrate and the thin film transistor for preventing impurities from the substrate from entering the thin film transistor, and

the buffer layer includes a silicon oxide layer, the silicon oxide layer having an opening in the region where the thin film transistor is not formed.

5. An electroluminescence display apparatus according to claim 1, wherein

the lower electrode of the electroluminescence element is formed of transparent conductive metal oxide,

the moisture blocking insulating film is either one of silicon nitride and tetraethoxysilane, and

the planarization insulating film is either one of resin, silicon nitride, and tetraethoxysilane.

6. An electroluminescence display apparatus according to claim 1, wherein

the region where the silicon oxide layers have an opening corresponds to an emissive region of the electroluminescence element.

7. An electroluminescence display apparatus according to claim 1, wherein

a light absorption member is disposed under the peripheral portion of the emissive region of the electroluminescence element.

8. An electroluminescence display apparatus according to claim 1, wherein

the thin film transistor is a top gate type thin film transistor in which a gate electrode layer is located above a silicon active layer.

9. An electroluminescence display apparatus comprising:

a thin film transistor including a silicon oxide layer, the thin film transistor being formed over a transparent substrate, and

an electroluminescence element formed on an insulating film which is formed so as to cover the thin film transistor, wherein

the electroluminescence element includes;

a transparent electrode which is connected with the thin film transistor, which is formed on the insulating film provided over the thin film transistor, and which extends toward the lateral region from a region where the thin film transistor is formed;

an emissive element layer including an emissive material, the emissive element layer being formed on the transparent electrode; and

an opposing electrode formed on the emissive element layer,

the silicon oxide layer of the thin film transistor has an opening at a position under an emissive region of the electroluminescence element, and

a light absorption member is provided under the peripheral portion of the emissive region of the electroluminescence element.

10. An electroluminescence display apparatus, comprising:

a top gate type thin film transistor in which a gate electrode layer is located above a silicon active layer, the thin film transistor being formed over a transparent substrate; and

an electroluminescence element formed over an insulating film which is formed so as to cover the thin film transistor, wherein

the electroluminescence element includes;

a transparent electrode which is connected with the thin film transistor, which is formed on the insulating film provided over the thin film transistor, and which extends toward the lateral region from a region where the thin film transistor is formed;

an emissive element layer including an emissive material, the emissive element layer being formed on the transparent electrode; and

an opposing electrode formed on the emissive element layer, and

the thin film transistor includes a silicon oxide layer which has an opening at a position under an emissive region of the electroluminescence element.

11. An electroluminescence display apparatus according to claim 10, wherein

a light absorption member is provided in the peripheral portion of the emissive region of the electroluminescence element and under the transparent electrode through which light emitted from the emissive element layer transmits.

12. An electroluminescence display apparatus according to claim 10, wherein

the silicon oxide layer is removed from an optical path along which light obtained in the emissive element layer transmits through the lower electrode to the substrate, such that no silicon oxide layer exists in the optical path.

13. An electroluminescence display apparatus according to claim 10, wherein

an inter-layer insulating film including a silicon oxide layer is formed between the thin film transistor and the moisture blocking insulating film which covers the thin film transistor,

a gate insulating film including a silicon oxide layer is formed between the silicon active layer and the gate electrode of the thin film transistor, and

both the silicon oxide layer of the inter-layer insulating film and the silicon oxide layer of the gate insulating film have an opening in the region where the thin film transistor is not formed.

14. An electroluminescence display apparatus according to claim 13, wherein

a buffer layer is formed between the substrate and the thin film transistor for preventing impurities from the substrate from entering the thin film transistor, and

the buffer layer includes a silicon oxide layer, the silicon oxide layer having an opening in the region where the thin film transistor is not formed.

15. An electroluminescence display apparatus according to claim 10, wherein

the lower electrode of the electroluminescence element is formed of transparent conductive metal oxide,

the moisture blocking insulating film is either one of silicon nitride and tetraethoxysilane, and

the planarization insulating film is either one of resin, silicon nitride, and tetraethoxysilane.