CN100524890C - Organic electroluminescent element, flat panel display and portable electronic device - Google Patents

Abstract

The invention provides an organic electroluminescent element, comprising a substrate, a transparent anode, a transparent cathode and an organic light-emitting layer, wherein the transparent anode and the transparent cathode are oppositely arranged on the substrate, and the organic light-emitting layer is arranged between the transparent anode and the transparent cathode. The organic electroluminescent element also comprises a light-transmitting optical compensation layer arranged between the transparent anode and the substrate or on the surface of the transparent cathode, and the light-transmitting optical compensation layer is made of transition metal oxide.

Description

Organic electroluminescence element, flat panel display and portable electronic device

technical field

The present invention relates to an organic electroluminescence device (organic electroluminescence device), in particular to an organic electroluminescence device provided with an optical compensation layer (optical compensator) on the surface of a transparent anode or a transparent cathode and the application of the organic electroluminescence device flat-panel displays and portable electronic devices.

Background technique

The organic electroluminescent element does not need to be equipped with a backlight module such as a liquid crystal display device, so the process can be simplified. With the rapid development of the technology of organic electroluminescent elements, organic electroluminescent elements have been gradually applied to various electronic devices with display areas, especially portable electronic devices, such as mobile phones, personal digital assistants, mobile phones, etc. Portable computers, digital cameras, digital video cameras, etc. How to improve the brightness and luminous efficiency of the organic electroluminescent element to reduce power consumption and prolong the service life of the organic electroluminescent element is one of the important topics developed by those skilled in the art.

U.S. Patent No. 5,714,838 discloses a top-emission organic electroluminescent element, by forming a calcium film or a calcium alloy film on the transparent electrode (ZnS, GaN, ITO, etc.) The substance diffuses into the organic light-emitting layer. However, the formation of the calcium thin film or calcium alloy thin film may affect the luminous efficiency of the organic electroluminescence device.

US Patent No. 6,831,407 discloses an organic light-emitting diode, which utilizes an uneven structure formed in an organic light-emitting layer to improve luminous efficiency. However, the process of forming the uneven structure is relatively complicated.

Therefore, there is a need to provide an organic electroluminescent element capable of improving luminous efficiency and simplifying the process and a flat panel display using the organic electroluminescent element.

Contents of the invention

In view of this, the object of the present invention is to provide an organic electroluminescent element, which utilizes an optical compensation layer to generate a constructive interference effect (construction interference), thereby improving the luminance efficiency (luminance efficiency) of the organic electroluminescent element, and even improving Color shift in viewing angle.

Another object of the present invention is to provide an organic electroluminescence element, select a single-layer or multi-layer transition metal oxide (transition metaloxide) that can be formed by evaporation (evaporation), to be adjacent to the transparent anode or transparent The cathode does not require complex processes to improve the production efficiency of organic electroluminescence components.

According to the above purpose, the present invention provides an organic electroluminescence element, comprising a substrate, a transparent anode, a transparent cathode oppositely arranged, and an organic light-emitting layer, the transparent anode and the transparent cathode are arranged on the above-mentioned substrate, and the organic light-emitting layer is arranged on between the transparent anode and the transparent cathode. The above-mentioned organic electroluminescence element also includes at least one optically transparent optical compensation layer disposed between the transparent anode and the substrate and/or disposed on the surface of the transparent cathode, and the material of the optically transparent optical compensation layer is made of transition metal oxide constitute.

Furthermore, the deposition thickness of the transition metal oxide used as the optical compensation layer may be less than 10,000 angstroms, and a thickness of 500 angstroms to 1000 angstroms is more preferable. Furthermore, the optical properties of this optical compensation layer are, for example, that the n value of the refractive index (n-ik) at the wavelength of visible light (380nm to 780nm) is approximately not greater than 3.5, and the k value of the refractive index (n-ik) is approximately is less than 0.2.

Furthermore, the above-mentioned optical compensation layer is, for example, made of a material with a light transmittance of over 40%. In addition, the higher the light transmittance of the optical compensation layer, the better the luminous efficiency.

Secondly, the methods for forming the optical compensation layer include electron beam deposition, thermal evaporation, molecular beam epitaxy, vapor phase epitaxy, or metalorganic chemical vapor deposition.

In addition, the present invention also provides a flat panel display and a portable electronic device using organic electroluminescent elements.

Furthermore, the above-mentioned portable electronic device is, for example, a mobile phone, a handheld game device, a digital camera, a digital video recorder, a digital playback device, a personal digital assistant or a portable computer.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be described in more detail below with reference to the accompanying drawings and preferred embodiments.

Description of drawings

FIG. 1 is a schematic cross-sectional view of an organic electroluminescent device with an optical compensation layer according to a first embodiment of the present invention.

2 is a schematic cross-sectional view of an organic electroluminescence device with an optical compensation layer according to a second embodiment of the present invention.

3 is a schematic cross-sectional view of an organic electroluminescent device with an optical compensation layer according to a third embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a single-layer optical compensation layer according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a multilayer optical compensation layer according to an embodiment of the present invention.

6 is a schematic cross-sectional view of an organic electroluminescence device with an optical compensation layer according to a fourth embodiment of the present invention.

7 is a schematic cross-sectional view of an organic electroluminescence device with an optical compensation layer according to a fifth embodiment of the present invention.

8 is a schematic cross-sectional view of an organic electroluminescent device with an optical compensation layer according to a sixth embodiment of the present invention.

FIG. 9 is a schematic diagram of a flat panel display according to an embodiment of the present invention.

FIG. 10A is a schematic diagram of a mobile phone including an organic electroluminescent device according to an embodiment of the present invention.

FIG. 10B is a schematic diagram of a digital camera including an organic electroluminescence element according to an embodiment of the present invention.

FIG. 10C is a schematic diagram of a personal digital assistant including an organic electroluminescence device according to an embodiment of the present invention.

FIG. 10D is a schematic diagram of a portable computer including an organic electroluminescence device according to an embodiment of the present invention.

FIG. 10E is a schematic diagram of a digital playback device including an organic electroluminescence device according to an embodiment of the present invention.

FIG. 10F is a schematic diagram of a digital video recorder including an organic electroluminescence device according to an embodiment of the present invention.

simple notation

10, 20, 30, 40, 50, 60, 70, 200～Organic electroluminescence element

100～substrate

102, 102a, 102b~the first light-transmitting optical compensation layer

103b～hole transport layer

103a～hole injection layer

104～transparent anode

105～polymer conductive layer

106～Organic light-emitting layer

107a～electron injection layer

107b～electron transport layer

108～transparent cathode

110～second light-transmitting optical compensation layer

A, B～light emitting direction

202～peripheral components

301, 401, 501, 601, 701, 802～main body

302, 602, 702～frame

303, 402, 502, 603, 702, 802～display area

306, 404, 504, 604, 706, 804～operation buttons

307, 405, 605～external connection part

308～antenna

406～shutter

403, 806～Video Receiving Department

503～Power switch

606～Touchpad mouse

705～Media reading department

707～speaker

803～Voice input unit

805～Battery

Detailed ways

FIG. 1 is a schematic cross-sectional view of a double-side emission type organic electroluminescence device with an optical compensation layer according to a first embodiment of the present invention. The organic electroluminescence device 10 includes a substrate 100 made of glass material, quartz or plastic substrate, a transparent anode 104 and a transparent cathode 108 opposite to each other. In addition, the organic electroluminescent device 10 further includes an organic light emitting layer 106 disposed between the transparent anode 104 and the transparent cathode 108 and in direct contact with the transparent anode 104 and the transparent cathode 108 . The organic electroluminescent element 10 also includes a first light transmissible optical compensation layer 102 disposed between the substrate 100 and the transparent anode and a second light transmissible optical compensation layer 110 disposed on the transparent cathode 108. . The first and second transparent optical compensation layers 102, 110 can be made of transition metal oxides not greater than 10,000 angstroms, and the thickness is preferably between 500 angstroms and 1000 angstroms, and the first transparent optical compensation layer The n value of the refractive index (n-ik) of the compensation layer 102 or the second light-transmitting optical compensation layer 110 is generally not greater than 3.5 in the wavelength range of 380nm to 780nm, and the k value of the refractive index (n-ik) varies between wavelengths The range between 380nm and 780nm is roughly less than 0.2.

The steps of forming the organic electroluminescent element 10 are to sequentially form a first light-transmitting optical compensation layer 102, a transparent anode 104, an organic light-emitting layer 106, a transparent cathode 108, and a second light-transmitting optical compensation layer on the surface of the substrate 100. 110. It should be noted that the above-mentioned first light-transmitting optical compensation layer 102 and the second light-transmitting optical compensation layer 110 can adopt thermal evaporation (thermal evaporation), electron beam deposition (electrical beam deposition), molecular beam epitaxy ( molecular beam epitaxy), vapor phase epitaxy (vapor phase epitaxy; VPE), metal organic chemical vapor deposition (metal organicchemical vapor deposition; MOCVD), or resistance heating evaporation.

Furthermore, the first light-transmitting optical compensation layer or the second light-transmitting optical compensation layer is selected from titanium dioxide (TiO ₂ ) layer, tungsten trioxide (WO ₃ ) layer, tantalum trioxide (Ta ₂ O ₃ ), five Vanadium oxide (V ₂ O ₅ ), zinc oxide (ZnO), zirconia (ZrO), cerium oxide (CeO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), gadolinium oxide (Gd ₂ O ₃ ), A group consisting of chromium trioxide (Cr ₂ O ₃ ), nickel oxide (NiO), bismuth oxide (Bi ₂ O ₃ ), samarium oxide (SmO) and neodymium oxide (Nd ₂ O ₅ ) or a combination thereof.

The first light-transmitting optical compensation layer 102 formed on the surface of the substrate 100 may be a double-layer structure including a lower optical compensation layer 102a and an upper optical compensation layer 102b, as shown in FIG. 4 . It can also be a single-layer structure as shown in FIG. 5 . Furthermore, the thicknesses of the lower optical compensation layer 102 a and the upper optical compensation layer 102 b are respectively between 500 angstroms and 1000 angstroms, preferably between 700 angstroms and 900 angstroms. However, the present invention is not limited thereto, and the first light-transmitting optical compensation layer 102 may also have a structure of more than two layers. Furthermore, the second light-transmitting optical compensation layer 110 may also be a single-layer, double-layer or more than double-layer structure.

The transparent anode 104 can be made of transparent conductive materials such as indium tin oxide (ITO) or indium zinc oxide (IZO) with a thickness of 700 angstroms to 800 angstroms. The transparent cathode 108 can be made of conductive materials such as indium tin oxide (ITO) and indium zinc oxide (IZO) with a thickness of 700 angstroms to 800 angstroms, or aluminum with a thickness of about 5 nanometers.

The organic light-emitting layer 106 is, for example, doped tris (8-hydroxyquinolinato) aluminum (III) Alq _{3 (} Tris (8-hydroxyquinolinato) aluminum (III). When biased, the applied voltage injects electrons and holes respectively from the transparent cathode 108 and the transparent anode 104 into the organic light-emitting layer 106, so that the chemical molecules in the organic light-emitting layer 106 are excited by energy to generate fluorescence (fluorescence) or Phosphorescence (phosphorescence), and then through the transparent anode 104, the first light-transmitting optical compensation layer 102 and the substrate 100 to release toward the light-emitting direction A (direction of the arrow). On the other hand, the fluorescence or phosphorescence generated by the organic light-emitting layer 106 also passes through The transparent cathode 108 and the second light-transmitting optical compensation layer 110 are released toward the light-emitting direction B (direction of the arrow). In detail, the organic electroluminescent element 10 of this embodiment can emit light upward (direction A) and light downward (B direction) double-sided emission type organic electroluminescent element.

Next, please refer to FIG. 2 , which is a schematic cross-sectional view of an organic electroluminescent element 20 with an optical compensation layer according to a second embodiment of the present invention. The organic electroluminescent element 20 of the second embodiment is the same as that of the first embodiment. The organic electroluminescent element 10 is substantially the same, including a first light-transmitting optical compensation layer 102, a transparent anode 104, an organic light-emitting layer 106, and a transparent cathode 108 sequentially formed on the substrate 100, but the organic electroluminescent element 10 is not formed. The second light-transmitting optical compensation layer 110 in.

Next, please refer to FIG. 3 , which is a schematic cross-sectional view of an organic electroluminescent element 30 with an optical compensation layer according to a third embodiment of the present invention. The organic electroluminescent element 20 of the third embodiment is similar to that of the first embodiment. The electroluminescent element 10 is substantially the same, including a transparent anode 104, an organic light-emitting layer 106, a transparent cathode 108, and a second transparent optical compensation layer 110 sequentially formed on the substrate 100. However, it is not necessary to form the organic electroluminescent element 10. The first light-transmitting optical compensation layer 102 in.

Then, please refer to FIG. 6 , which is a schematic cross-sectional view of an organic electroluminescent device 40 with an optical compensation layer according to a fourth embodiment of the present invention. The organic electroluminescent element 40 of the fourth embodiment is substantially the same as the organic electroluminescent element 10 of the first embodiment, including a first light-transmitting optical compensation layer 102, a transparent anode 104, and an organic light-emitting element formed on the substrate 100 in sequence. layer 106, a transparent cathode 108, and a second light-transmitting optical compensation layer 110, and the organic electroluminescent element 40 also includes a polymer conductive layer 105 set between the transparent anode 104 and the organic light-emitting layer 106, as a hole injection layer, for example, a mixture of polystyrene dioxythiophene (PEDT) or polystyrene sulfonate (PSS). The organic light-emitting layer 106 of this embodiment may use poly(p-phenylene vinylene); PPV.

Next, please refer to FIG. 7 , which is a schematic cross-sectional view of an organic electroluminescent device 50 with an optical compensation layer according to a fifth embodiment of the present invention. The organic electroluminescent element 50 of the fifth embodiment is substantially the same as the organic electroluminescent element 10 of the first embodiment, including a first light-transmitting optical compensation layer 102 , a transparent anode 104 , and an organic light-emitting element formed on the substrate 100 in sequence. layer 106, a transparent cathode 108, and a second light-transmitting optical compensation layer 110. The organic electroluminescent device 50 of the fifth embodiment further includes a hole transport layer 103b and an electron transport layer 107b. The hole injection layer 103a can be made of NPB (naphtha-phenyl benzidine), and the electron transport layer 107b can be made of Alq3.

Then, please refer to FIG. 8 , which is a schematic cross-sectional view of an organic electroluminescent device 60 with an optical compensation layer according to a sixth embodiment of the present invention. The organic electroluminescent element 60 of the sixth embodiment is substantially the same as the organic electroluminescent element 50 of the fifth embodiment, including a first light-transmitting optical compensation layer 102, a transparent anode 104, and a hole formed on the substrate 100 in sequence. Transport layer 103b, organic light-emitting layer 106, electron transport layer 107b, transparent cathode 108, and second light-transmitting optical compensation layer 110, the organic electroluminescent element 50 of the sixth embodiment also includes a hole injection layer 103a and an electron injection layer 107a. The hole injection layer 103a is, for example, CuPc (copper phthalocyanine). A lithium fluoride thin film can be used for the electron injection layer 107a.

In the above embodiments of the present invention, an optical compensation layer is provided on the light-emitting side of the transparent anode 104 and/or transparent cathode 108 of the organic electroluminescent element. After verification, it is found that the luminous efficiency of the organic electroluminescent element has been significantly improved. In addition, It also improves the color shift phenomenon of the organic electroluminescent element on the viewing angle.

9 is a schematic diagram of a flat-panel display according to an embodiment of the present invention, which includes a flat-panel display combined with any organic electroluminescent element 200 of the embodiment of the present invention, an external frame and a peripheral element 202 of an external circuit.

An example of a portable electronic device using the organic electroluminescent element of any embodiment of the present invention is described below.

FIG. 10A is a schematic diagram of a mobile phone including an organic electroluminescent element according to an embodiment of the present invention. The mobile phone includes a main body 301, an outer frame 302, a display area 303 using an organic electroluminescent element according to any embodiment of the present invention, and operation buttons 306 , an external connection part 307 , and an antenna 308 .

FIG. 10B is a schematic diagram of a digital camera including an organic electroluminescence element according to an embodiment of the present invention. The digital camera shown in FIG. 10B includes a main body 401 , a display area 402 using an organic electroluminescent device according to any embodiment of the present invention, an image receiving portion 403 , operation buttons 404 , an external connection portion 405 , and a shutter 406 .

FIG. 10C is a schematic diagram of a personal digital assistant including an organic electroluminescent element according to an embodiment of the present invention. The personal digital assistant includes a main body 501, a display area 502 using an organic electroluminescent element according to any embodiment of the present invention, a power switch 503, Operation button 504 and infrared port 505 .

Fig. 10D is a schematic diagram of a portable computer including an organic electroluminescent element according to an embodiment of the present invention. The portable computer includes a main body 601, an outer frame 602, and a display area using an organic electroluminescent element according to any embodiment of the present invention 603 , an operation button 604 , an external connection part 605 and a touchpad mouse 606 .

FIG. 10E is a schematic diagram of a digital playback device including an organic electroluminescent element according to an embodiment of the present invention. This digital playback device is a digital video disc or a similar playback device. It includes a main body 701, an outer frame 702, and the The display area 703 , the media reading part 705 , the operation buttons 706 and the speaker 707 of the organic electroluminescent element in any embodiment of the invention.

FIG. 10F is a schematic diagram of a digital video recorder including an organic electroluminescent element according to an embodiment of the present invention. The digital video recorder includes a main body 801, an organic electroluminescent element 802 using any embodiment of the present invention, a voice input unit 803, and operation buttons 804. , a battery 805 and an image receiving unit 806 .

Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention It shall prevail as defined in the appended claims.

Claims (14)

1. organic electroluminescent element comprises:

One substrate;

The transparent cathode that one transparent anode and is oppositely arranged is arranged on this substrate;

One organic luminous layer is arranged between this transparent anode and this transparent cathode;

One first light transmission optical compensating layer is arranged between this transparent anode and this substrate; And

One second light transmission optical compensating layer is arranged on this transparent cathode;

Wherein this first light transmission optical compensating layer or the second light transmission optical compensating layer are selected from group or its combination that is made of tungstic acid, three oxidations, two tantalums, vanadic oxide, ceria, niobium pentaoxide, gadolinium oxide, chrome green, nickel oxide, bismuth oxide, samarium oxide and neodymia.

2. organic electroluminescent element as claimed in claim 1, wherein the n value of the refractive index (n-ik) of this first light transmission optical compensating layer or the second light transmission optical compensating layer is not more than 3.5 between wave-length coverage 380nm to 780nm, and the k value of refractive index (n-ik) between wave-length coverage 380nm to 780nm less than 0.2.

3. organic electroluminescent element as claimed in claim 1, wherein this first light transmission optical compensating layer or the second light transmission optical compensating layer are single layer structure.

4. organic electroluminescent element as claimed in claim 1, wherein this first light transmission optical compensating layer or the second light transmission optical compensating layer are sandwich construction.

5. organic electroluminescent element as claimed in claim 1, wherein the thickness of this first light transmission optical compensating layer or the second light transmission optical compensating layer is not more than 10,000 dusts.

6. organic electroluminescent element as claimed in claim 5 is wherein between thickness in 500 to 1000 dusts of this first light transmission optical compensating layer or the second light transmission optical compensating layer.

7. organic electroluminescent element as claimed in claim 1, wherein this transparent anode comprises indium tin oxide or indium-zinc oxide.

8. organic electroluminescent element as claimed in claim 1, wherein this transparent cathode comprises indium tin oxide or indium-zinc oxide.

9. organic electroluminescent element as claimed in claim 1 also comprises a hole injection layer, is arranged between this transparent anode and this organic luminous layer.

10. organic electroluminescent element as claimed in claim 1 also comprises:

One electron transfer layer is adjacent to this transparent cathode; And

One hole transmission layer is adjacent to this transparent anode.

11. organic electroluminescent element as claimed in claim 1, wherein this first light transmission optical compensating layer or the second light transmission optical compensating layer by electron beam deposition, hot evaporation, molecular beam epitaxy, vapour phase epitaxy, and Metalorganic chemical vapor deposition any and form.

12. a flat-panel screens comprises organic electroluminescent element as claimed in claim 1.

13. a portable electronic device comprises organic electroluminescent element as claimed in claim 1.

14. portable electronic device as claimed in claim 13, wherein this portable electronic device comprises mobile phone, hand held game device, digital code camera, digital video recorder, digital broadcast device, personal digital assistant, portable computer.

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