Light emitting apparatus and electronic device

• US 20040017335A1
• Filed: 04/23/2003
• Published: 01/29/2004
• Est. Priority Date: 05/10/2002
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kobayashi, Hidekazu, Miyashita, Satoru
• Granted Patent: US 7,242,140 B2
• Time in Patent Office: Days
• US Class Current: 345/82
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

An organic EL apparatus comprising a substrate 2, a pair of electrodes 7 and 8 formed on the substrate 2, and a light emitting layer 5 disposed between the electrodes 7 and 8 is provided in order to implement a light emitting apparatus and an electronic device which decrease reflections in a display of the organic EL apparatus, and to improve display quality. The substrate 2 comprises a transparent substrate, the pair of the electrodes 7 and 8 is an anode 7 disposed on the light emitting layer 5 at the substrate 2 side, and a cathode 7 disposed on the light emitting layer 5 at an opposite side of the substrate 2. A semi-reflection film 1 is disposed near the anode 7. The semi-reflection film transmits a part of external light R₀ incident on the organic EL apparatus from the substrate 2, and reflects a part of the light other than the light transmitted.

Claims

1. A light emitting apparatus, comprising:

an organic electroluminescence element including

a substrate, a first electrode, a second electrode, and a light emitting layer sandwiched between the first and second electrodes,

wherein the organic electroluminescence element comprises a semi-reflection film that reflects at least a part of light.

2. A light emitting apparatus as claimed in claim 1, wherein the first and second electrodes are a cathode and an anode, respectively.

3. A light emitting apparatus as claimed in claim 1, wherein the first electrode has a light transmission property, and the second electrode has a light reflection property.

4. A light emitting apparatus as claimed in claim 1, wherein the semi-reflection film is disposed on the light emitting layer at the substrate side.

5. A light emitting apparatus as claimed in claim 1, wherein at least one of the first and second electrodes has a light reflection property, and

wherein a thickness of the light emitting layer is set such that first reflection light and second reflection light are interfered and attenuated each other;

the first reflection light being incident on the light emitting apparatus and reflected by the semi-reflection film; and

the second reflection light being reflected by the electrode having the reflection property.

6. A light emitting apparatus as claimed in claim 5, wherein a reflectance of the semi-reflection film is set such that an intensity of the first reflection light is approximately the same as that of the second reflection light.

7. A light emitting apparatus as claimed in claim 1, wherein at least one of the first and second electrodes has a light reflection property, and

wherein a thickness of the light emitting layer is set such that a phase of the first reflection light is deviated from a phase of the second reflection light at an angle of about 180°

;

the first reflection light being incident on the light emitting apparatus and reflected by the semi-reflection film; and

the second reflection light being reflected by the electrode having the light reflection property.

8. A light emitting apparatus as claimed in claim 7, wherein a reflectance of the semi-reflection film is set such that an intensity of the first reflection light is approximately the same as that of the second reflection light.

9. A light emitting apparatus as claimed in claim 1, wherein the semi-reflection film transmits about 50 percent of the light incident on the semi-reflection film, and reflects about 50 percent of the light incident thereon.

10. A light emitting apparatus as claimed in claim 1, further comprising:

a plurality of pixel apertures on which the light emitting layer is disposed, spaces between the pixel apertures on which the light emitting layer is not disposed, a transparent layer and a reflection layer formed on the spaces between the pixels,

wherein a thickness of the transparent layer is set such that a third reflection light and a fourth reflection light are interfered and attenuated each other;

the third reflection light being incident on the spaces between the pixels, reflected by the semi-reflection film and left from the spaces between the pixels; and

the fourth reflection light being transmitted through the semi-reflection film and the transparent layer, and reflected by the reflection layer.

11. A light emitting apparatus as claimed in claim 10, wherein the semi-reflection film is disposed on the spaces between the pixels.

12. A light emitting apparatus as claimed in claim 10, wherein a reflectance of the semi-reflection film is set such that an intensity of the third reflection light is approximately the same as that of the fourth reflection light.

13. A light emitting apparatus as claimed in claim 1, further comprising:

a plurality of pixel apertures on which the light emitting layer is disposed, spaces between the pixel apertures on which the light emitting layer is not disposed, a transparent layer and a reflection layer formed on the spaces between the pixels,

wherein a thickness of the transparent layer is set such that a phase of the third reflection light is deviated from a phase of the fourth reflection light at an angle of about 180°

;

the third reflection light being incident on the light emitting apparatus, reflected by the semi-reflection film and left from the spaces between the pixel; and

the fourth reflection light being transmitted through the semi-reflection film and the transparent layer, and reflected by the reflection layer.

14. A light emitting apparatus as claimed in claim 13, wherein the semi-reflection film is disposed on the spaces between the pixels.

15. A light emitting apparatus as claimed in claim 13, wherein a reflectance of the semi-reflection film is set such that an intensity of the third reflection light is approximately the same as that of the fourth reflection light.

16. A light emitting apparatus as claimed in claim 13, comprising a thin film transistor, wherein the reflection layer functions as an electrode in the thin film transistor.

17. A light emitting apparatus as claimed in claim 1, wherein the semi-reflection film is formed near one of the first and second electrodes.

18. A light emitting apparatus as claimed in claim 3, wherein the first electrode also acts as the semi-reflection film.

19. A light-emitting apparatus as claimed in claim 1, comprising a plurality of scanning lines and a plurality of data lines formed in a matrix, switching means connected to the scanning lines and the data lines, and pixel electrodes connected to the switching means.

20. An electronic device, comprising the light emitting apparatus as claim in claim 1.