KR100760881B1 - Organic electroluminescent device, process for fabricating the same and display - Google Patents

Abstract

On the anode electrode 16 and the anode electrode 16 having the light reflection film 12 formed on the insulating substrate 10 and the transparent conductive film 14 formed to cover the light reflection film 12 on the light reflection film 12. It is formed on the organic electroluminescent layer 18 formed on the organic electroluminescent layer 18, and has the cathode electrode 20 which has light transmittance. As a result, high luminous efficiency can be realized without deterioration of device characteristics.

Organic Electroluminescent Devices, Display Units

Description

ORGANIC ELECTROLUMINESCENT DEVICE, PROCESS FOR FABRICATING THE SAME AND DISPLAY}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an organic electroluminescent device, a method for manufacturing the same, a display device, and a method for manufacturing the same. In particular, an organic electroluminescent device, a method for manufacturing the same, and an organic electroluminescent device having excellent luminous efficiency, A display device having an element is provided.

BACKGROUND ART As a display device that can be made thinner and lighter than a conventional CRT and LCD, a display device using an organic electroluminescent element (EL) has recently attracted great attention. Since the organic electroluminescent device is a self-luminous type, a film substrate having high visibility, no viewing angle dependence, and flexibility can be used, which is thinner and lighter than the liquid crystal display device. In addition, in order to realize high-definition display, development of an active matrix display device having a switching element such as a thin film transistor, together with an organic electroluminescent element, is in progress.

In the display apparatus using the conventional organic electroluminescent element, the anode electrode which consists of transparent conductive films, such as ITO (indium oxide doped with tin), is formed on the insulating substrate which consists of a glass substrate, for example. On the anode electrode, an organic electroluminescent layer including a light emitting layer in which light is generated by recombination of electrons and holes is formed. On the organic electroluminescent layer, a cathode electrode made of an Al (aluminum) film, an Mg (magnesium) -Ag (silver) alloy film, or the like is formed. In this way, the organic electroluminescent element which has an anode electrode, an organic electroluminescent layer, and a cathode electrode is formed on an insulating substrate. In the active matrix display device, a switching element such as a thin film transistor for controlling a driving voltage applied to the organic electroluminescent element is formed between the insulating substrate and the organic electroluminescent element. The display device having such a structure has a so-called bottom emission type in which light generated in the light emitting layer of the organic electroluminescent layer is taken out from the side of the insulating substrate.

In the above-described display apparatus, in the case of realizing full color, light emitting layers having different light emission wavelengths are divided into pixel regions. For example, it is performed to form the light emitting layer which forms each color of RGB, for example by moving a deposition mask in order of RGB, by making the vapor deposition mask which the area | region which becomes a pixel become an opening close to a board | substrate, and forming each color of RGB.

In the case of a bottom emission display device, as described above, light generated in the organic electroluminescent element is taken out from the side of the insulating substrate. For this reason, when a switching element is formed between an insulating substrate and an organic electroluminescent element, the light emitting area which occupies one pixel becomes substantially small by presence of a switching element, and there exists a difficulty that a high luminous efficiency cannot be obtained.

In order to solve such a problem regarding the light emission efficiency, a solution has been attempted by a so-called top emission type structure in which light generated in the light emitting layer is extracted from the side opposite to the insulating substrate side on which the switching element is formed, that is, from the cathode electrode side. (See Patent Documents 1 and 2, for example).

In the top emission display device disclosed in Patent Document 1, by using a cathode electrode having a light transmissive property and using a Cr (chromium) thin film having a light reflection property as an anode electrode, the light generated in the light emitting layer is reflected to the cathode electrode side, Light is taken out from the cathode electrode. However, Cr does not reflect light generated in the light emitting layer sufficiently to the cathode electrode side because the reflectance of light is not so high.

In addition, in the top emission display device disclosed in Patent Document 2, an electrode layer made of an ITO film is directly formed on a reflective layer made of an Al film. However, since the Al film and the ITO film had poor electrical connection, it was difficult to use the reflective layer as an electrode.

For this reason, when a switching element was formed under a reflection layer, connection of an electrode layer and a switching element was difficult.

An object of the present invention is to provide an organic electroluminescent element capable of realizing high luminous efficiency, a method of manufacturing the same, and a display device having such an organic electroluminescent element.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2001-85163

[Patent Document 2] Japanese Patent Application Laid-Open No. 11-329753

Disclosure of the Invention

According to one aspect of the invention, an anode having a first conductive film having a light reflectivity and a second conductive film formed on the substrate to cover the first conductive film and having a light transmissive property. An organic electroluminescent device is provided, comprising: an electrode, an organic electroluminescent layer formed on the anode electrode, and a cathode electrode formed on the organic electroluminescent layer and having a light transmissive property.

According to another aspect of the present invention, there is provided a first conductive film having a light reflectivity, a second conductive film formed on the first conductive film, having a light transmissive property, and the first conductive film. An anode electrode formed partially between the second conductive films and electrically connected to each of the first conductive film and the second conductive film, an organic electroluminescent layer formed on the anode electrode, And an organic electroluminescent device formed on the organic electroluminescent layer and having a cathode having light transmittance.

In addition, according to another aspect of the present invention, formed on a substrate, a first conductive film having a light reflectivity, formed on the first conductive film, an insulating layer having a light transmittance, and formed on the insulating layer And an anode electrode having a second conductive film having light transmittance, an organic electro luminescence layer formed on the anode electrode, and a cathode electrode formed on the organic electro luminescence layer, and having light transmittance. An organic electroluminescent device is provided.

According to still another aspect of the present invention, there is provided a first conductive film having light reflectivity on the substrate and a second conductive film formed on the first conductive film so as to cover the first conductive film and having a light transmissive property. And a step of forming an anode electrode, a step of forming an organic electro luminescence layer on the anode electrode, and a step of forming a cathode electrode having light transparency on the organic electro luminescence layer. There is provided a method for producing an organic electroluminescent device.

Moreover, according to another viewpoint of this invention, the process of forming a switching element on a board | substrate, the process of forming a 1st insulating layer on the said board | substrate with the said switching element formed, and the said 1st insulating layer, A step of forming a reflective first conductive film, on the first insulating layer on which the first conductive film is formed, a second insulating layer made of a photosensitive resin having a first opening on an electrode of the switching element and having a light transmissive property. Forming a second opening layer by etching the first insulating layer using the second insulating layer as a mask, and forming a second opening reaching the electrode of the switching element, on the second insulating layer. And electrically connecting to an electrode of the switching element with the second opening interposed therebetween to form an anode having a second conductive film having light transparency, on the anode electrode. And a step of forming an organic electroluminescent layer, and a step of forming a cathode electrode having light transparency on the organic electroluminescent layer.

According to the present invention, the anode is formed on a substrate, and is formed so as to cover the first conductive film on the first conductive film and the first conductive film having light reflectivity, and the second conductive film having light transparency. By doing so, light generated in the organic electroluminescent layer is taken out from the cathode electrode side, whereby high light emission efficiency can be realized without deterioration of device characteristics.

According to the present invention, the first conductive film and the second conductive film are partially formed between the first conductive film and the second conductive film by partially forming a third conductive film electrically connected to each of the first conductive film and the second conductive film. Since conduction between conductive films is ensured, holes can be injected into the organic electroluminescent layer from the first conductive film.

Moreover, according to this invention, the anode electrode which has a 2nd conductive film which has a light transmittance is formed on the 1st conductive film which is formed on a board | substrate, and has a light transmissive insulating layer between them, Since the light generated in the organic electroluminescent layer is taken out from the cathode electrode side by the first conductive film under the anode electrode, high light emission efficiency can be realized without deterioration of device characteristics.

1 is a schematic view showing the structure of a display device according to a first embodiment of the present invention.

2 is a schematic view showing an example of the structure of a bottom emission display device using an organic electroluminescent element.

3 is a (first) step cross-sectional view showing the method for manufacturing the display device according to the first embodiment of the present invention.

4 is a (second) cross-sectional view showing the method for manufacturing the display device according to the first embodiment of the present invention.

5 is a schematic view showing the structure of a display device according to a second embodiment of the present invention.

6 is a (first) cross-sectional view showing the method for manufacturing the display device according to the second embodiment of the present invention.

7 is a (second) cross-sectional view showing the method for manufacturing the display device according to the second embodiment of the present invention.

8 is a schematic view showing the structure of a display device according to a third embodiment of the present invention.

9 is a cross-sectional view showing the structure of a display device according to a fourth embodiment of the present invention.

10 is a cross-sectional view showing the structure of a display device according to a fifth embodiment of the present invention.

11 is a cross-sectional view showing an example of a structure of a bottom emission type display device using a thin film transistor as a switching element together with an organic electroluminescent element.

12 is a (first) cross-sectional view showing the method for manufacturing the display device according to the fifth embodiment of the present invention.

13 is a (second) cross-sectional view showing the method for manufacturing the display device according to the fifth embodiment of the present invention.

14 is a cross-sectional view showing the structure of a display device according to a sixth embodiment of the present invention.

15 is a graph showing the characteristics of the display device according to the sixth embodiment of the present invention.

16 is a cross-sectional view showing the structure of a display device using a Cr film as an anode electrode.

17 is a (first) cross-sectional view showing the method for manufacturing the display device according to the sixth embodiment of the present invention.

18 is a (second) cross-sectional view showing the method for manufacturing the display device according to the sixth embodiment of the present invention.

19 is a cross-sectional view showing the structure of a display device according to a seventh embodiment of the present invention.

20 is a (first) cross-sectional view showing the method for manufacturing the display device according to the seventh embodiment of the present invention.

21 is a (second) cross-sectional view showing the method for manufacturing the display device according to the seventh embodiment of the present invention.

22 is a (third) step cross-sectional view showing the manufacturing method of the display device according to the seventh embodiment of the present invention.

To practice the invention  Best form for

(1st embodiment)

A display device and a manufacturing method thereof according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4. 1 is a schematic view showing the structure of a display device according to the present embodiment, FIG. 2 is a schematic view showing the structure of a bottom emission type display device using an organic electroluminescent element, and FIGS. 3 and 4 are displays according to the present embodiment. It is process sectional drawing which shows the manufacturing method of an apparatus.

First, the structure of the display device according to the present embodiment will be described with reference to FIG. 1. 1A is a plan view showing the structure of a display device according to the present embodiment, and FIG. 1B is a sectional view taken along the line X-X 'of FIG. 1A. The display device according to the present embodiment is a passive matrix display device having an organic electroluminescent element formed on an insulating substrate.

In addition, although FIG. 1 shows the structure for one pixel, actually, several pixel is arrange | positioned in matrix form.

As shown to FIG. 1B, the light reflection film 12 which consists of an Al film which has light reflectivity is formed on the insulating substrate 10 which consists of glass substrates. On the light reflection film 12, a transparent conductive film 14 made of an ITO film having light transparency is formed. In addition, in this specification, "having light reflectivity" means that the reflectance of light is 50% or more, More preferably, it is 80% or more. In addition, "having light transmittance" means that light transmittance is 50% or more, More preferably, it is 80% or more. In this way, the anode electrode 16 which has the light reflection film 12 and the transparent conductive film 14 is formed on the insulating substrate 10. On the anode electrode 16, an organic electroluminescent layer 18 in which a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are sequentially stacked is formed. On the organic electroluminescent layer 18, the cathode electrode 20 which consists of an Al / ITO laminated film which has a light transmittance is formed. In this way, the organic electroluminescent element which has the anode electrode 16, the organic electroluminescent layer 18, and the cathode electrode 20 is formed on the insulating substrate 10. As shown in FIG.

As shown to FIG. 1A, the anode electrode 16 is extended and formed in the predetermined direction (up-down direction in FIG. 1A) on the insulating substrate 10. As shown in FIG. The transparent conductive film 14 is formed more widely than the light reflection film 12. As a result, the light reflection film 12 is covered with the transparent conductive film 14. The cathode electrode 20 is extended and formed in the direction (left-right direction in FIG. 1A) orthogonal to the anode electrode 16 on the insulating substrate 10 in which the anode electrode 16 was formed. The organic electroluminescent layer 18 is formed in the rectangular shape which is wider than an intersection area | region between both of these areas where the anode electrode 16 and the cathode electrode 20 cross | intersect. In this way, the pixel region in which the organic electroluminescent element which has the said structure was formed is comprised.

In the display device according to the present embodiment, in the organic electroluminescent element, the anode electrode 16 includes a light reflecting film 12 having a light reflectivity and a transparent conductive film 14 having a light transmissivity, and a light reflecting film ( 12) The main feature is that the transparent conductive film 14 is covered.

In the display device according to the present embodiment, electrons are injected from the cathode electrode 20 into the organic electroluminescent layer 18, and holes from the transparent conductive film 14 of the anode electrode 16 are organic electroluminescent. Injected into layer 18. The injected electrons are transported to the light emitting layer by the electron transport layer, and the injected holes are transported to the light emitting layer by the hole transport layer. In this way, electrons and holes transported to the light emitting layer are recombined in the light emitting layer to generate light emission. Light generated in the light emitting layer is reflected by the light reflection film 12 to the cathode electrode 20 side, and is extracted from the cathode electrode 20 side having light transparency.

As described above, the display device according to the present embodiment has a top emission type in which light is extracted from the cathode electrode 20 side opposite to the insulating substrate 10 due to the presence of the light reflection film 12. Therefore, in the case where another element is formed between the insulating substrate 10 and the organic electroluminescent element, it is possible to extract light even from a region where the other element is formed. In other words, the luminous area of the organic electroluminescent element is not limited by other elements, and high luminous efficiency can be realized. For example, in the case where an organic electroluminescent element is formed on an insulating substrate on which a switching element such as a thin film transistor is formed with an interlayer insulating film interposed therebetween, the light emitting area is not limited by the switching element. Efficiency can be realized.

With respect to the display device according to the present embodiment of such a top emission type, the display device shown in FIG. 2 is a bottom emission type display device using an organic electroluminescent element. FIG. 2A is a plan view showing the structure of a bottom emission display device using an organic electroluminescent element, and FIG. 2B is a sectional view taken along the line X-X 'of FIG. 2A. 2 shows a structure for one pixel, but a plurality of pixels are actually arranged in a matrix.

As shown in FIG. 2, the transparent anode electrode 102 which consists of an ITO film | membrane is formed on the insulating substrate 100 which consists of glass substrates. On the anode electrode 102, an organic electroluminescent layer 104 formed by sequentially laminating a hole transporting layer, a light emitting layer, and an electron transporting layer is formed. On the organic electroluminescent layer 104, a cathode electrode 106 made of an Al film, an Mg-Ag alloy film, or the like is formed. In this way, the organic electroluminescent element which has the anode electrode 102, the organic electroluminescent layer 104, and the cathode electrode 106 is formed on the insulating substrate 100. As shown in FIG.

In the bottom emission display device illustrated in FIG. 2, light generated in the organic electroluminescent layer 104 is extracted from the insulating substrate 100 side. For this reason, when another element, such as a switching element, is formed between the insulating substrate 10 and an organic electroluminescent element, the light emitting area of an organic electroluminescent element is restrict | limited by the other element, It is difficult to realize high luminous efficiency like a display device.

In the display device according to the present embodiment, the light reflection film 12 made of the Al film is covered with the transparent conductive film 14 made of the ITO film so that the surface thereof is not exposed in the anode electrode 16. have. Thereby, when patterning the ITO film | membrane in a manufacturing process, it can prevent that the light reflection film 12 which consists of Al films corrodes. That is, since an alkaline developer is used for patterning the ITO film, when the surface of the Al film is exposed and both the Al film and the ITO film are exposed to the developer, the Al film may corrode due to the battery effect. In the display device according to the present embodiment, since the transparent conductive film 14 made of the ITO film is formed to cover the light reflection film 12 made of the Al film, corrosion of the light reflection film 12 due to such a battery effect is prevented. It is being prevented.

In addition, whiskers may be generated between the light reflection film 12 made of the Al film and the transparent conductive film 14 made of the ITO film due to heat generation or the like when the driving voltage is applied to the organic electroluminescent element. Such a whisker may be one of the causes of the inter-electrode short circuit. However, in the display device according to the present embodiment, since the transparent conductive film 14 made of the ITO film is formed so as to cover the light reflection film 12 made of the Al film, the anode electrode 16 and the cathode electrode by whiskers are formed. Short circuit between 20 can be prevented.

In addition, the Al film has a higher reflectance than the Cr film conventionally used, and is suitable as a light reflection film of an organic electroluminescent element. On the other hand, when an Al film is used as the light reflection film, the above problems arise. In the display device according to the present embodiment, the ITO film is formed so as to cover the Al film, thereby realizing higher luminous efficiency than before without accompanying problems such as corrosion and short circuit between electrodes.

In addition, the organic electroluminescent layer 18 is formed on the transparent conductive film 14 which consists of an ITO film like the conventional organic electroluminescent element. For this reason, as the organic electroluminescent layer 18, the organic electroluminescent layer of the same material and structure as the conventional organic electroluminescent element is used as it is, and the top emission type display device which has high luminous efficiency is comprised. can do.

Next, the manufacturing method of the display device which concerns on this embodiment is demonstrated using FIG. 3 and FIG.

First, an Al film 22 having a film thickness of 150 nm is formed on the insulating substrate 10 made of a glass substrate, for example, by a sputtering method (see FIG. 3A).

Subsequently, the Al film 22 is patterned into a predetermined shape by photolithography and etching. In this way, the light reflection film 12 which consists of Al films 22 is formed on the insulating substrate 10 (refer FIG. 3B).

Next, an ITO film 24 having a film thickness of 70 nm, for example, is formed on the insulating substrate 10 on which the light reflection film 12 is formed (see FIG. 3C).

Subsequently, the ITO film 24 is patterned into a predetermined shape by photolithography and etching. At this time, the ITO film 24 is patterned in a shape and a size covering the light reflection film 12 so that the surface of the light reflection film 12 is not exposed. In this way, the transparent conductive film 14 which consists of the ITO film 24 is formed (refer FIG. 4A). During patterning of the ITO film 24, since the surface of the light reflection film 12 made of the Al film 22 under the ITO film 24 is not exposed, corrosion of the light reflection film 12 due to the battery effect is prevented. You can prevent it.

Subsequently, on the insulating substrate 10 on which the anode electrode 16 having the light reflection film 12 and the transparent conductive film 14 was formed, a vapor deposition mask opened to a predetermined size by, for example, a vacuum deposition method, was interposed therebetween. For example, 2-TNATA (4,4 ', 4''-tris (2-naphthylphenylamino) triphenylamine) film having a thickness of 40 nm, for example, α-NPD (10 nm thick) N, N'-dinaphthyl-N, N'-diphenyl- [1,1'-biphenyl] -4,4'-diamine) membranes, for example small amounts of t (npa) py (1,3 Alq ₃ (tris (8-hydroxyquinolinate) aluminum) film having a thickness of 30 nm, for example, doped with 6,8-tetra (N-naphthyl-N'-phenylamino) pyrene) For example, an Alq ₃ film having a film thickness of 20 nm, for example, a LiF film having a thickness of 0.5 nm is sequentially formed.

Thus, a hole injection layer consisting of a 2-TNATA film, a hole transporting layer consisting of an α-NPD film, a light emitting layer consisting of an Alq ₃ film doped with t (npa) py, an electron transporting layer consisting of an Alq ₃ film, and an electron consisting of a LiF film An organic electroluminescent layer 18 having an injection layer is formed (see FIG. 4B).

Subsequently, on the insulating substrate 10 in which the organic electroluminescent layer 18 was formed, a mask opened in a predetermined shape by, for example, a vacuum deposition method and a sputtering method, was interposed, for example, a film thickness of 10 An Al film having a thickness of nm, for example, an ITO film having a thickness of 30 nm is sequentially formed to form an Al / ITO laminated film.

In this way, the cathode electrode 20 which consists of Al / ITO laminated films is formed (refer FIG. 4C).

In this way, the display device shown in FIG. 1 is manufactured.

As described above, according to the present embodiment, in the display device using the organic electroluminescent element, the anode electrode 16 has the light reflection film 12 having light reflectivity and the transparent conductive film 14 having light transparency. Therefore, a top emission display device having a high luminous efficiency can be realized.

In addition, since the light reflection film 12 is covered with the transparent conductive film 14, the device characteristics due to corrosion of the light reflection film 12 or a whisker generated between the light reflection film 12 and the transparent conductive film 14 or the like. Deterioration can be suppressed.

In addition, since the organic electroluminescent layer 18 is formed on the transparent conductive film 14 like the conventional organic electroluminescent element, as the organic electroluminescent layer 18, the conventional organic electroluminescent The organic electroluminescent layer of the same material and structure as a neSense element can be used as it is.

(2nd embodiment)

A display device according to a second embodiment of the present invention will be described with reference to FIGS. 5 to 7. 5 is a schematic view showing the structure of the display device according to the present embodiment, and FIGS. 6 and 7 are process cross-sectional views showing the method for manufacturing the display device according to the present embodiment. In addition, the same code | symbol is attached | subjected about the component similar to the display apparatus which concerns on 1st Embodiment shown in FIG. 1, FIG. 3, and the manufacturing method, and its manufacturing method, or abbreviate | omits.

The display device according to the present embodiment is a passive matrix display device having an organic electroluminescent element formed on an insulating substrate, like the display device according to the first embodiment, and the basic configuration thereof is the first embodiment. The same applies to the display device. In the display device according to the present embodiment, the conduction between the light reflection film 12 and the transparent conductive film 14 is ensured, and the display according to the first embodiment can be performed in that holes can be injected from the light reflection film 12. It is different from the device.

First, the structure of the display device according to the present embodiment will be described with reference to FIG. 5. 5A is a plan view showing the structure of the display device according to the present embodiment, and FIG. 5B is a sectional view taken along the line X-X 'of FIG. 5A. Although FIG. 5 shows a structure for one pixel, a plurality of pixels are actually arranged in a matrix.

 As shown to FIG. 5B, the light reflection film 12 which consists of an Al film which has a light reflection property is formed on the insulating substrate 10 which consists of glass substrates. On the peripheral part of the light reflection film 12, an intervening film 30 made of a Mo (molybdenum) film having light reflectivity is formed. On the light reflection film 12 in which the interposition film 30 is formed on the peripheral portion, a transparent conductive film 14 made of an ITO film having light transparency is formed. The interposition film 30 is electrically connected to each of the light reflection film 12 and the transparent conductive film 14, and the interlayer film 30 electrically controls the transparent conductive film 14 and the light reflection film 12. The connection is improved, and the conduction between the two is secured. In this way, the anode electrode 32 which has the light reflection film 12, the transparent conductive film 14, and the interposition film 30 which improves the electrical connection of both is formed on the insulating substrate 10. As shown in FIG. On the anode electrode 32, an organic electroluminescent layer 18 in which a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are sequentially stacked is formed. On the organic electroluminescent layer 18, the cathode electrode 20 which consists of an Al / ITO laminated film which has a light transmittance is formed. In this way, the organic electroluminescent element which has the anode electrode 32, the organic electroluminescent layer 18, and the cathode electrode 20 is formed on the insulating substrate 10. As shown in FIG.

As shown in FIG. 5A, the anode electrode 32 is extended and formed in the predetermined direction (up-down direction in FIG. 5A) on the insulating substrate 10. As shown in FIG. The interposition film 30 is formed in a frame shape on the periphery of the light reflection film 12. The transparent conductive film 14 is formed wider than the light reflection film 12 in which the interposition film 30 was formed. Thereby, the light reflection film 12 in which the interposition film 30 was formed is covered with the transparent conductive film 14. The cathode electrode 20 is extended and formed in the direction (left-right direction in FIG. 5A) orthogonal to the anode electrode 16 on the insulating substrate 10 in which the anode electrode 16 was formed. The organic electroluminescent layer 18 is formed in the rectangular shape which is wider than an intersection area | region between both the areas where these anode electrodes 32 and the cathode electrode 20 cross | intersect. In this way, the pixel region in which the organic electroluminescent element which has the said structure was formed is comprised.

In the organic electroluminescent device, the display device according to the present embodiment is formed on the light reflection film 12 having the light reflection property and the peripheral edge of the light reflection film 12, and the light reflection film 12 and the light reflection film 12 The interlayer film 30 and the interlayer film 30 for electrically connecting to each of the transparent conductive films 14 formed on the upper surface of the transparent conductive film 14 are formed on the light reflection film 12 formed on the periphery. The anode electrode 32 has the transparent conductive film 14 which has a light transmittance, and the main reflection is that the light reflection film 12 is covered by the transparent conductive film 14.

Since the Al film and the ITO film have poor electrical connection, in the display device according to the first embodiment, the light reflecting film 12 made of Al film and the transparent conductive film 14 made of ITO film in the anode electrode 16. There is a case where the conduction between the two is not sufficiently secured.

In the display device according to the present embodiment, the peripheral portion of the anode electrode 32 has an Al / Mo / ITO structure. For this reason, the electrical connection between the light reflection film 12 which consists of Al films, and the transparent conductive film 14 which consists of ITO films by the intervening film 30 which consists of Mo films electrically connected to each of Al film and ITO film | membrane is carried out. This has been improved and the conduction between the two is secured. Therefore, holes can be injected from the light reflection film 12 into the organic electroluminescent layer 18. In addition, since the interposition film 30 is formed on the periphery of the light reflection film 12, the interlayer film 30 is formed on the light emitting layer of the organic electroluminescent layer 18 by the light reflection film 12 having a higher reflectance than the interposition film 30. The generated light can be sufficiently reflected on the cathode electrode 20 side.

In addition, since the transparent conductive film 14 is formed so as to cover the light reflection film 12 on which the intervening film 30 is formed on the periphery, like the display device according to the first embodiment, the light reflection film 12 is corroded. Can be prevented. In addition, a short circuit between the anode electrode 32 and the cathode electrode 20 due to the whisker generated between the light reflection film 12 and the transparent conductive film 14 due to heat generation when the driving voltage is applied can be prevented. In addition, the organic electroluminescent layer of the conventional organic electroluminescent element can be used for the organic electroluminescent layer 18 as it is.

Next, the manufacturing method of the display device which concerns on this embodiment is demonstrated using FIG. 6 and FIG.

First, on the insulating substrate 10 which consists of a glass substrate, the Al film | membrane 22 with a film thickness of 150 nm is formed by the sputtering method, for example.

Subsequently, an Mo film 34 having a film thickness of 10 nm, for example, is formed on the Al film 22 by the sputtering method (see FIG. 6A).

Next, the resist film 36 is formed on the Mo film 34 by, for example, a spin coat method. Next, by patterning the resist film 36 using photolithography, the resist film 36 is left so as to cover a region to be formed of the light reflection film 12 in which the Al film 22 should remain. At this time, the film thickness of the periphery of the resist film 36 covering the region to be formed of the interlayer film 30 in which the Mo film 34 should remain is thick, the Mo film 34 is removed, and the Al film 22 is removed. The resist film 36 is left so that the film thickness of parts other than the peripheral part of the resist film 36 which covers the area | region which should remain | survives becomes thin (refer FIG. 6B).

Thickness setting of the film thickness of the said resist film 36 can be performed by adjusting an exposure amount with the mask used for photolithography, for example. Specifically, for example, in the mask used for photolithography, a portion for exposing the resist film 36 covering the region to be formed of the interlayer film 30 in which the Mo film 34 should remain is usually exposed. On the other hand, the part which exposes the resist film 36 which covers the area | region in which the Mo film | membrane 34 is removed and the Al film | membrane 22 must remain is made into a slit shape. When the resist film 36 is developed using such a mask, the resist film 36 covering the region where the Mo film 34 should be removed and the Al film 22 should remain is the region to be formed of the interlayer film 30. Exposure is inadequate compared with the resist film 36 which covers the film. Thus, by developing partially changing the exposure amount of the resist film 36, a thick foil can be formed in the film thickness of the resist film 36. FIG.

Subsequently, unnecessary Al film 22 and Mo film 34 other than the formation region of the anode electrode 32 are removed by, for example, wet etching, using the resist film 36 having a thick film formed thereon as a mask. (See FIG. 6C). For wet etching, for example, an etching solution obtained by mixing phosphoric acid, nitric acid, acetic acid, and water can be used.

Subsequently, the thin portion of the film thickness of the resist film 36 covering the region where the resist film 36 is to be etched back by, for example, ashing treatment, and the Mo film 34 is removed and the Al film 22 must remain. Is removed to form the openings 38 in the resist film 36. On the other hand, the thick part of the film thickness of the resist film 36 which covers the formation area | region of the interposition film 30 is left (refer FIG. 6D).

Subsequently, the Mo film 34 exposed to the bottom of the opening 38 is removed by, for example, wet etching, using the resist film 36 having the opening 38 formed thereon as a mask. For wet etching, as in the case where the unnecessary Mo film 34 and Al film 22 are removed in FIG. 6C, for example, an etching solution in which phosphoric acid, nitric acid, acetic acid, and water are mixed can be used.

Next, the resist film 36 used as a mask is removed.

In this way, the interstitial film 30 which consists of the light reflection film 12 which consists of Al films 22, and the Mo film 34 formed on the periphery of the light reflection film 12 is formed (refer FIG. 7A).

Subsequently, an ITO film 24 having a thickness of 70 nm, for example, is formed on the insulating substrate 10 on which the light reflection film 12 and the intervening film 30 are formed, for example, by a sputtering method (FIG. 7B). See).

Subsequently, the ITO film 24 is patterned into a predetermined shape by photolithography and etching. At this time, the ITO film 24 is patterned in the shape and size which coat | cover the light reflection film 12 so that the surface of the light reflection film 12 in which the interposition film 30 was formed on the peripheral part may not be revealed. In this way, the transparent conductive film 14 which consists of the ITO film 24 is formed (refer FIG. 7C).

Subsequently, the organic electroluminescent layer 18 and the cathode electrode 20 are formed in the same manner as in the manufacturing method of the display device according to the first embodiment shown in FIGS. 4B and 4C, respectively. The display device by form is manufactured.

As described above, according to the present embodiment, in the display device using the organic electroluminescent element, the anode electrode 32 has the light reflective film 12 having light reflectivity and the transparent conductive film 14 having light transparency. Therefore, a top emission display device having a high luminous efficiency can be realized.

In addition, since the light reflection film 12 is covered with the transparent conductive film 14, the device characteristics due to corrosion of the light reflection film 12 or a whisker generated between the light reflection film 12 and the transparent conductive film 14 or the like. Deterioration can be suppressed.

In addition, on the periphery of the light reflection film 12, an interlayer film for electrically connecting to each of the light reflection film 12 and the transparent conductive film 14 formed on the light reflection film 12 to ensure conduction therebetween ( Since 30) is formed, holes can be injected from the light reflection film 12 into the organic electroluminescent layer 18.

In addition, since the organic electroluminescent layer 18 is formed on the transparent conductive film 14 like the conventional organic electroluminescent element, as the organic electroluminescent layer 18, the conventional organic electroluminescent The organic electroluminescent layer of the same material and structure as a neSense element can be used as it is.

(Third embodiment)

The display device and the manufacturing method thereof according to the third embodiment of the present invention will be described with reference to FIG. 8 is a schematic view showing the structure of the display device according to the present embodiment. In addition, the same code | symbol is attached | subjected about the same component as the display apparatus by 1st and 2nd embodiment shown in FIG. 1 and 5, and description is abbreviate | omitted or simplified.

In the display device according to the present embodiment, light generated in the light emitting layer of the organic electroluminescent layer is extracted from the cathode electrode side opposite to the insulating substrate in one pixel in which the organic electroluminescent element formed on the insulating substrate is formed. And a double-sided light emitting portion where light generated in the light emitting layer of the organic electroluminescent layer is extracted from both sides of the cathode electrode side and the insulating substrate side.

Hereinafter, the structure of the display device according to the present embodiment will be described with reference to FIG. 8. 8A is a plan view showing the structure of the display device according to the present embodiment, FIG. 8B is a sectional view taken along the line X-X 'of FIG. 8A, and FIG. 8C is a sectional view taken along the line Y-Y' of FIG. 8A. In addition, although FIG. 8 shows the structure for one pixel, actually, the some pixel is arrange | positioned in matrix form.

As shown to FIG. 8A, on the insulating substrate 10 which consists of glass substrates, like the display apparatus by 1st and 2nd embodiment, the transparent conductive film 14, the organic electroluminescent layer 18, and the cathode The electrode 20 is formed. The pixel region where the transparent conductive film 14 and the cathode electrode 20 intersect are divided into two substantially equilateral regions by a boundary orthogonal to the extending direction of the transparent conductive film 14. In the region on one side of the boundary, the light reflection film 12 is formed under the transparent conductive film 14, and the top light emitting part 40 in which the anode electrode 32 having the light reflection film 12 and the transparent conductive film 14 is formed. ) Is formed. In the region on the other side of the boundary, the light reflection film 12 is not formed, and the double-side light emitting portion 44 in which the anode electrode 42 made of the transparent conductive film 14 is formed is formed.

The upper surface light emission part 40 has the cross-sectional structure shown in FIG. 8B. The cross-sectional structure shown in FIG. 8B has the same cross-sectional structure as the display device according to the second embodiment. That is, on the insulating substrate 10, the light reflection film 12 which consists of Al films which have light reflection property is formed. On the peripheral part of the light reflection film 12, the interposition film 30 which consists of Mo films | membrane which has light reflection property is formed. On the light reflection film 12 in which the interposition film 30 is formed on the peripheral portion, a transparent conductive film 14 made of an ITO film having light transparency is formed. The interposition film 30 is electrically connected to each of the light reflection film 12 and the transparent conductive film 14, and the interlayer film 30 electrically controls the transparent conductive film 14 and the light reflection film 12. The connection is improved, and the conduction between the two is secured. In this way, the anode electrode 32 which has the light reflection film 12, the transparent conductive film 14, and the interposition film 30 which improves the electrical connection of both is formed on the insulating substrate 10. As shown in FIG. On the anode electrode 32, an organic electroluminescent layer 18 in which a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are sequentially stacked is formed. On the organic electroluminescent layer 18, the cathode electrode 20 which consists of an Al / ITO laminated film which has a light transmittance is formed. In this way, on the insulating substrate 10 in the top surface light-emitting part 40, it has the anode electrode 32 which has the light reflection film 12, the organic electroluminescent layer 18, and the cathode electrode 20. An organic electroluminescent element is formed. In the top emission part 40, the light generated in the organic electroluminescent layer 18 is reflected by the light reflection film 12 to the cathode electrode 20 side, and from the cathode electrode 20 side having light transparency. It is taken out.

The double-sided light emitting portion 44 has a cross-sectional structure shown in FIG. 8C. That is, the anode electrode 42 which consists of the transparent conductive film 14 common to the upper surface light emission part 40 is formed on the insulating substrate 10. FIG. Unlike the top light emitting part 40, in the double-side light emitting part 44, the light reflection film 12 is not formed, and the transparent conductive film 14 is formed directly on the insulating substrate 10. On the anode electrode 42, the organic electroluminescent layer 18 common to the top light emission part 40 is formed. On the organic electroluminescent layer 18, the cathode electrode 20 which has the light transmittance common to the upper surface light emission part 40 is formed. In this way, the organic electroluminescent element which has the anode electrode 42, the organic electroluminescent layer 18, and the cathode electrode 20 on the insulating substrate 10 in the double-sided light emitting part 44 is Formed. In the double-sided light emitting portion 44, the light generated in the organic electroluminescent layer 18 is not formed with the light reflection film 12, and is formed from both sides of the cathode electrode 20 side and the insulating substrate 10 side. It is taken out.

Thus, the transparent conductive film 14 and the cathode electrode which form the area | region in which the light reflection film 12 was formed in the same pixel, and the area | region in which the light reflection film 12 is not formed, ie, are common to the anode electrodes 32 and 42 By partially forming the light reflection film 12 in the overlapping light emitting region, the top emission type region and the double side emission type region may be formed in the same pixel.

In addition, in this embodiment, although the top light emitting part 40 and the double-sided light emitting part 44 were made into substantially the same shape mutually, the shape of both light emitting parts 40 and 44 is not limited to this. By appropriately changing the shape of the light reflection film 12 partially formed in the same pixel, the shapes of both light emitting portions 40 and 44 can be made desired. Thereby, it becomes possible to set light emission characteristics, such as brightness | luminance, as desired according to the use, function, etc. of a display apparatus.

In addition, in this embodiment, although the anode electrode 32 similar to the display apparatus by 2nd embodiment was used in the top surface light-emitting part 40, in the 1st embodiment in which the interposition film 30 is not formed, An anode electrode 16 such as a display device may be used in the upper surface light emitting part 40.

In addition, in this embodiment, although the light reflection film 12 was partially formed in the same pixel, the pixel in which the light reflection film 12 was formed and the light reflection film 12 were formed with respect to the several pixel arrange | positioned in matrix form. The pixel which is not formed may be formed, and the top emission pixel and the double emission pixel may be mixed.

(4th embodiment)

A display device and a manufacturing method thereof according to a fourth embodiment of the present invention will be described with reference to FIG. 9 is a sectional view showing the structure of a display device according to the present embodiment. 1, 3, and 4, the same components as those of the display device according to the first embodiment and the method of manufacturing the same are denoted by the same reference numerals to omit or simplify the description thereof.

The display device according to the present embodiment has the main feature that the smooth unevenness is formed on the surface of the insulating substrate 10 in the display device according to the first embodiment.

That is, as shown in FIG. 9, smooth unevenness | corrugation is formed in the surface of the insulating substrate 10 which consists of a glass substrate. On the insulating substrate 10 having smooth unevenness on the surface, like the display device according to the first embodiment, the anode electrode 16 and the organic electroluminescent layer having the light reflection film 12 and the transparent conductive film 14 are provided. 18 and the cathode electrode 20 are formed.

In the display device according to the present embodiment, the anode electrode 16, the organic electroluminescent layer 18, and the cathode, which are formed on the insulating substrate 10, by smooth irregularities formed on the surface of the insulating substrate 10. The area of the electrode 20 is larger than the case where it is formed on the insulating substrate 10 of the flat surface on which the unevenness | corrugation is not formed. Thereby, luminous efficiency can be improved further.

As a method of forming the unevenness on the surface of the insulating substrate 10, a method as described below can be used.

For example, irregularities can be directly formed on the surface of the insulating substrate 10 by etching the surface of the insulating substrate 10 using a solution such as sulfuric acid.

Or after coating the insulating substrate 10 with resin etc., the predetermined pattern which consists of resin etc. is formed on the insulating substrate 10 using the exposure method, and the surface of the insulating substrate 10 is made of resin, etc. Unevenness with or without it can be formed.

According to the first embodiment shown in Figs. 3A to 3C and 4A to 4C, the display device according to the present embodiment forms smooth unevennesses on the surface of the insulating substrate 10 by using the above-described method. Can be manufactured in the same manner as in the manufacturing method of the display device.

Thus, according to this embodiment, since smooth unevenness | corrugation is formed in the surface of the insulating board | substrate 10 in which an organic electroluminescent element is formed, luminous efficiency can be improved further.

In the present embodiment, the case where the smooth irregularities are formed on the surface of the insulating substrate 10 in the display device according to the first embodiment has been described. However, the display devices according to the second and third embodiments are described. Also, by forming smooth unevenness on the surface of the insulating substrate 10 as described above, the luminous efficiency can be further improved.

(5th embodiment)

A display device and a manufacturing method thereof according to a fifth embodiment of the present invention will be described with reference to FIGS. 10 to 13. Fig. 10 is a sectional view showing the structure of the display device according to the present embodiment, Fig. 11 is a sectional view showing an example of the structure of a bottom emission type display device using a thin film transistor as a switching element together with an organic electroluminescent element. 13 is a cross-sectional view illustrating the method of manufacturing the display device according to the present embodiment. In addition, about the component similar to the display apparatus which concerns on 2nd Embodiment shown in FIG. 5, and its manufacturing method, the same code | symbol is attached | subjected and description is abbreviate | omitted or simplified.

In the display device according to the present embodiment, a thin film transistor is formed as a switching element together with an organic electroluminescent element similar to the display device according to the second embodiment, and the thin film transistor is used for the organic electroluminescent element. An active matrix display device for controlling a driving voltage to be applied. Hereinafter, the structure of the display device according to the present embodiment will be described with reference to FIG. 10. In addition, although FIG. 10 shows the structure for one pixel, actually, several pixel is arrange | positioned in matrix form.

On the insulating substrate 10 made of a glass substrate, a buffer layer 46 made of a silicon oxide film is formed. On the buffer layer 46, a channel layer 48 made of a polysilicon film is formed. On the channel layer 48, a gate electrode 52 is formed with a gate insulating film 50 made of a silicon oxide film interposed therebetween. In the channel layer 48 on both sides of the gate electrode 52, a source region 54 and a drain region 56 are formed, respectively. In this way, the insulating substrate 10 has a gate electrode 52, a source region 54 and a drain region 56 formed in the channel layer 48, and controls the driving voltage applied to the organic electroluminescent element. A thin film transistor is formed.

An interlayer insulating film 58 is formed on the insulating substrate 10 on which the thin film transistor is formed. On the interlayer insulating film 58, the source electrode 62 connected to the source region 54 with the contact hole 60 therebetween, and the drain electrode connected to the drain region 56 with the contact hole 64 interposed therebetween ( 66) are formed respectively.

An interlayer insulating film 68 is formed on the interlayer insulating film 58 on which the source electrode 62 and the drain electrode 66 are formed. In the interlayer insulating film 68, a contact hole 70 reaching the source electrode 62 is formed.

On the interlayer insulating film 68 on which the contact holes 70 are formed, a light reflection film 12 made of an Al film having light reflectivity is formed in a region including the contact holes 70. On the peripheral part of the light reflection film 12, the interposition film 30 which consists of Mo films | membrane which has light reflection property is formed. On the light reflection film 12 in which the interposition film 30 is formed on the peripheral portion, a transparent conductive film 14 made of an ITO film having light transparency is formed. The interposition film 30 is electrically connected to each of the light reflection film 12 and the transparent conductive film 14, and the interlayer film 30 is electrically connected to the transparent conductive film 14 and the light reflection film 12. It is improved and the conduction between them is secured. In this way, the anode electrode 32 which has the light reflection film 12, the transparent conductive film 14, and the interposition film 30 for ensuring the conduction between both is formed on the interlayer insulation film 68. As shown in FIG. The anode electrode 32 is electrically connected to the source electrode 62 of the thin film transistor with the contact hole 70 formed in the interlayer insulating film 68 interposed therebetween.

On the anode electrode 32, an organic electroluminescent layer 18 in which a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are sequentially stacked is formed. On the organic electroluminescent layer 18, the cathode electrode 20 which consists of an Al / ITO laminated film which has a light transmittance is formed. In this way, the organic electroluminescent element which has the anode electrode 32, the organic electroluminescent layer 18, and the cathode electrode 20 is formed on the interlayer insulation film 68. As shown in FIG.

The display device according to the present embodiment has a top emission type in which light is extracted from the cathode electrode 20 side opposite to the insulating substrate 10 due to the presence of the light reflection film 12. Therefore, the light emitting area is not limited by the thin film transistor formed on the insulating substrate 10, and high light emitting efficiency can be realized.

With respect to the display device according to the present embodiment of such a top emission type, the display device shown in FIG. 11 is a bottom emission type display device using a thin film transistor together with an organic electroluminescent element as a switching element. 11 shows a structure for one pixel, but a plurality of pixels are actually arranged in a matrix.

As shown in FIG. 11, the buffer layer 108 is formed on the insulating substrate 100 which consists of a glass substrate. The channel layer 110 is formed on the buffer layer 108. On the channel layer 110, the gate electrode 114 is formed with the gate insulating film 112 interposed therebetween. Source regions 116 and drain regions 118 are formed in the channel layers 110 on both sides of the gate electrode 114, respectively. Thus, on the insulating substrate 100, a thin film transistor having a gate electrode 114, a source region 116 and a drain region 118 formed in the channel layer 110 is formed.

The interlayer insulating film 120 is formed on the insulating substrate 100 on which the thin film transistor is formed. On the interlayer insulating film 120, a source electrode 124 connected to the source region 116 with a contact hole 122 interposed therebetween, and a drain electrode connected to the drain region 118 with a contact hole 126 interposed therebetween ( 128) are formed respectively.

An interlayer insulating film 130 is formed on the interlayer insulating film 120 on which the source electrode 124 and the drain electrode 128 are formed. In the interlayer insulating film 130, a contact hole 132 reaching the source electrode 124 is formed.

On the interlayer insulating film 130 on which the contact holes 132 are formed, in the region including the contact holes 132, a transparent anode electrode 102 made of an ITO film, an organic electroluminescent layer 104, an Al film or Mg An organic electroluminescent element having a cathode electrode 106 made of an -Ag alloy film or the like is formed. The anode electrode 102 is electrically connected to the source electrode 124 of the thin film transistor with the contact hole l32 formed in the interlayer insulating film 130 interposed therebetween.

In the bottom emission display device illustrated in FIG. 11, light generated in the organic electroluminescent layer 104 is extracted from the insulating substrate 100 side. For this reason, the light emitting area of the organic electroluminescent element is limited by the thin film transistor formed between the insulating substrate 10 and the organic electroluminescent element, thereby achieving high light emitting efficiency as in the display device according to the present embodiment. Difficult to do

In addition, since the display device according to the present embodiment has the anode electrode 32 having the same structure as the display device according to the second embodiment, the interlayer film 30 includes a light reflection film 12 made of an Al film; The electrical connection of the transparent conductive film 14 which consists of an ITO film | membrane is improved, and the conduction between them is ensured. As a result, holes can be injected into the organic electroluminescent layer 18 from the light reflection film 12 electrically connected to the source electrode 62 of the thin film transistor. Moreover, since the transparent conductive film 14 is formed so that the light reflection film 12 in which the interposition film 30 was formed may be formed on the peripheral part, the corrosion of the light reflection film 12 can be prevented. In addition, a short circuit between the anode electrode 32 and the cathode electrode 20 due to a whisker generated between the light reflection film 12 and the transparent conductive film 14 due to heat generation when the driving voltage is applied can be prevented. As the organic electroluminescent layer 18, an organic electroluminescent layer of the same material and structure as the organic electroluminescent layer of the conventional organic electroluminescent element can be used as it is.

Next, a manufacturing method of the display device according to the present embodiment will be described with reference to FIGS. 12 and 13.

First, the buffer layer 46 which consists of a silicon oxide film with a film thickness of 300 nm, for example is formed by the CVD method, for example on the insulating substrate 10 which consists of a glass substrate.

Next, a polysilicon film having a film thickness of 40 nm is formed on the buffer layer 46 by, for example, CVD. In addition, an amorphous silicon film may be formed instead of the polysilicon film, and crystallized by a laser annealing method or the like to form a polysilicon film.

Subsequently, the polysilicon film is patterned by photolithography and dry etching to form a channel layer 48 made of the polysilicon film (see FIG. 12A).

Subsequently, a silicon oxide film having a thickness of 100 nm, for example, is formed on the buffer layer 46 on which the channel layer 48 is formed, for example, by the CVD method.

Subsequently, an AlNd (aluminum-neodymium alloy) film having, for example, a film thickness of 300 nm is formed by a sputtering method.

Subsequently, a silicon oxide film and an AlNd film are patterned by photolithography and dry etching, and a gate insulating film 50 made of a silicon oxide film and a gate electrode 52 made of an AlNd film are formed on the channel layer 48.

Subsequently, phosphorus ions are ion implanted using the gate electrode 52 as a mask, for example, by an ion implantation method, and the source region 54 and the drain region 56 are formed on both channel layers 48 of the gate electrode 52. Form each.

In this way, a thin film transistor having a gate electrode 52, a source region 54 and a drain region 56 formed in the channel layer 48 is formed on the insulating substrate 10 (see FIG. 12B).

Subsequently, an interlayer insulating film 58 made of, for example, a silicon nitride film having a film thickness of 300 nm is formed on the insulating substrate 10 on which the thin film transistor is formed, for example, by a CVD method.

Subsequently, contact holes 60 reaching the source region 54 and contact holes 64 reaching the drain region 56 are formed in the interlayer insulating film 58 by photolithography and dry etching (FIG. 12c).

Subsequently, a Ti (titanium) / Al / Ti film having a thickness of 100 nm / 100 nm / 100 nm, for example, is deposited on the interlayer insulating film 58 on which the contact holes 60 and 64 are formed, for example, by a sputtering method. Form.

Subsequently, the Ti / Al / Ti film is patterned by photolithography and dry etching to form a source electrode 62 and a drain electrode 66 each formed of a Ti / Al / Ti film (see FIG. 13A).

Subsequently, an interlayer insulating film 68 made of a photosensitive resin having a film thickness of 3.0 μm is formed on the interlayer insulating film 58 on which the source electrode 62 and the drain electrode 66 are formed, for example, by the CVD method. do.

Subsequently, a contact hole 70 reaching the source electrode 62 is formed in the interlayer insulating film 68 by lithography (see FIG. 13B).

Subsequently, on the interlayer insulating film 68 on which the contact holes 70 are formed, it is connected to the source electrode 62 with the contact holes 70 interposed in the same manner as in the manufacturing method of the display device according to the second embodiment. The anode electrode 32, the organic electroluminescent layer 18, and the cathode electrode 20 are formed (see FIG. 13C).

In this way, the display device by this embodiment shown in FIG. 10 is manufactured.

As described above, according to the present embodiment, in the active matrix display device using the organic electroluminescent element, the light reflecting film 12 having light reflectivity and the transparent conductive film 14 having light transmissivity are used as the anode electrode 32. ), A top emission type display device having a high luminous efficiency can be realized without being limited by the thin film transistor formed under the organic electroluminescent element.

In addition, since the light reflection film 12 is covered with the transparent conductive film 14, the device characteristics due to corrosion of the light reflection film 12 or a whisker generated between the light reflection film 12 and the transparent conductive film 14 or the like. Deterioration can be suppressed.

In addition, on the periphery of the light reflection film 12, an interlayer film for electrically connecting to each of the light reflection film 12 and the transparent conductive film 14 formed on the light reflection film 12 to ensure conduction therebetween ( Since 30) is formed, holes can be injected into the organic electroluminescent layer 18 from the light reflection film 12 electrically connected to the source electrode 62 of the thin film transistor.

In addition, since the organic electroluminescent layer 18 is formed on the transparent conductive film 14 similarly to the conventional organic electroluminescent element, as the organic electroluminescent layer 18, the conventional organic electroluminescent The organic electroluminescent layer of the same material and structure as a neSense element can be used as it is.

In the present embodiment, an organic electroluminescent element similar to the display device according to the second embodiment is formed on the interlayer insulating film 68, but the same as the display device according to the first or third embodiment. An organic electroluminescent element may be formed. In the case where the interlayer film 30 is not formed between the light reflection film 12 and the transparent conductive film 14 as in the display device according to the first embodiment, the contact that reaches the source electrode 62 is not included. It is preferable that the transparent conductive film 14 is directly connected to the source electrode 62 by means such as not embedding the light reflection film 12 in the hole 70.

In the display device according to the fourth embodiment, an interlayer insulating film in which smooth unevenness is formed on the surface of the interlayer insulating film 68 and smooth unevenness is formed, similarly to the case where smooth unevenness is formed on the surface of the insulating substrate 10 ( You may form an organic electroluminescent element on 68).

(6th Embodiment)

The display device according to the sixth embodiment of the present invention will be described with reference to FIGS. 14 to 18. 14 is a sectional view showing the structure of a display device according to the present embodiment, FIG. 15 is a graph showing the characteristics of the display device according to the present embodiment, FIG. 16 is a sectional view showing the structure of a display device using a Cr film as an anode electrode, and FIG. 17 and 18 are cross-sectional views illustrating the method of manufacturing the display device according to the present embodiment. 1, 3, and 4, the same components as those of the display device according to the first embodiment and the manufacturing method thereof will be denoted by the same reference numerals to omit or simplify the description thereof.

The display device according to the present embodiment is a passive matrix display device having an organic electroluminescent element formed on an insulating substrate, similarly to the display device according to the first embodiment, and the basic configuration thereof is the first embodiment. Is the same as the display device. The display device according to the present embodiment differs from the display device according to the first embodiment in that an anode electrode made of a transparent conductive film is formed on the light reflection film with an insulating layer having light transparency therebetween.

First, the structure of the display device according to the present embodiment will be described with reference to FIG. In addition, although FIG. 14 shows a structure for one pixel, a plurality of pixels are actually arranged in a matrix.

As shown in FIG. 14, on the insulating substrate 10 which consists of glass substrates, the light reflection film 72 which consists of Al films which have a light reflection property is formed. The light reflection film 72 may be formed for each pixel having a predetermined shape or may be formed on the entire surface of the display area in which the pixels are arranged.

On the light reflection film 72, the insulating layer 74 which consists of photosensitive resin which has light transmittance is formed. As photosensitive resin which is a material of the insulating layer 74, acrylic resin is used, for example. The insulating layer 74 is formed so as to cover the light reflection film 72 so that the surface of the light reflection film 72 is not exposed.

On the insulating layer 74, an anode 76 made of a transparent conductive film of ITO having light transparency is formed. On the anode electrode 76, an organic electroluminescent layer 18 formed by sequentially laminating a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer is formed. On the organic electroluminescent layer 18, a transparent conductive film composed of an Al film having a thin film thickness and having a light transmittance, an Ag film having a thin film thickness and having a light transparency and an ITO film having light transparency is sequentially laminated. The formed cathode electrode 20 is formed. In this way, on the insulating substrate 10, the light reflection film 72 and the insulating layer 74 are interposed, and the anode electrode 76, the organic electroluminescent layer 18, and the cathode electrode 20 are provided. An organic electroluminescent element is formed.

In the display device according to the present embodiment, electrons are injected from the cathode electrode 20 into the organic electroluminescent layer 18, and holes are injected from the anode electrode 76 into the organic electroluminescent layer 18. . The injected electrons are transported to the light emitting layer by the electron transport layer, and the injected holes are transported to the light emitting layer by the hole transport layer. In this way, electrons and holes transported to the light emitting layer are recombined in the light emitting layer to generate light emission. Light generated in the light emitting layer is emitted to the anode electrode 76 side and the cathode electrode 20 side. The light emitted to the anode electrode 76 side is reflected by the light reflection film 72 to the cathode electrode 20 side with the light transmissive insulating layer 74 interposed therebetween, and the insulating layer 74 and the anode electrode ( 76, and the organic electroluminescent layer 18 is interposed therebetween, and is taken out from the side of the cathode electrode 20 having light transparency. Light emitted to the cathode electrode 20 side is taken out from the cathode electrode 20 side which has light transmittance as it is. In this way, the light which generate | occur | produced in the light emitting layer is taken out from the cathode electrode 20 side which has light transparency.

As described above, the display device according to the present embodiment is opposite to the insulating substrate 10 due to the existence of the light reflection film 72 formed under the anode electrode 76 made of a transparent conductive film with the insulating layer 74 interposed therebetween. It is a top emission type from which light is taken out from the cathode electrode 20 side of the. Therefore, in the case where another element is formed between the insulating substrate 10 and the organic electroluminescent element, as in the display device according to the first embodiment, it is possible to extract light even from the region where the other element is formed. . That is, the light emitting area of the organic electroluminescent device is not limited by other devices, and high light emission efficiency can be realized.

In addition, when another element is formed under the light reflection film 72, you may form the light reflection film 72 more broadly than the light emitting area | region in which the anode electrode 76 and the cathode electrode 20 overlap. Thus, by forming the light reflection film 72 widely, it can suppress that the light emission of an organic electroluminescent element affects the characteristic of another element.

Moreover, it is preferable to set the film thickness of the insulating layer 74 which has the light transmittance formed between the anode electrode 76 and the light reflection film 72 to 1 micrometer or more. This is because if the film thickness of the insulating layer 74 is set smaller than 1 µm, the photosensitive due to the interference effect of light may be generated in the insulating layer 74, and sufficient luminous efficiency may not be obtained.

FIG. 15 shows the display device according to the present embodiment and the display device using the anode electrode made of the Cr film shown in FIG. 16, by varying the current density injected into the organic electroluminescent layer to measure luminance, thereby providing both display devices. A graph showing the results of comparing the characteristics of The horizontal axis of the graph shown in FIG. 15 represents the current density injected into the organic electroluminescent layer, and the vertical axis represents the luminance of the measured display device. In addition, in the graph shown in FIG. 15, the plot indicated by 를 indicates a measurement result for the display device according to the present embodiment, and the plot indicated by 은 is a display device using an anode electrode made of a Cr film shown in FIG. 16. The measurement result is shown.

In the display device according to the present embodiment, an Al film having a thickness of 100 nm is used as the light reflection film 72, and an acrylic resin layer having a thickness of 3.0 μm is used as the insulating layer 74, and has a thickness of 70 nm as the anode electrode 76. ITO membrane was used. Further, as the organic electroluminescent layer 18, a hole injection layer made of a 2-TNATA film having a thickness of 140 nm, a hole transport layer made of an α-NPD film having a thickness of 10 nm, and a small amount of t (npa) py are used. the electron injection layer made of a light-emitting layer formed, a LiF film having an electron transport layer, made of a thick 0.5㎚ 20㎚ the Alq ₃ layer doped with the Alq ₃ film thickness are sequentially laminated was used 30㎚ made. As the cathode electrode 20, an Al film having a thickness of 1.5 nm, an Ag film having a thickness of 15 nm, and an ITO film having a thickness of 35 nm were sequentially stacked.

The display device shown in FIG. 16 comparing the characteristics with the display device according to the present embodiment is a top emission display device using a Cr film as an anode electrode. As shown in the drawing, an anode electrode 134 made of a Cr film is formed on an insulating substrate 100 made of a glass substrate. On the anode 134, the organic electroluminescent layer 104 is formed. On the organic electroluminescent layer 104, a cathode electrode 106 is formed. The organic electroluminescent layer 104 and the cathode electrode 106 have the exception that the anode electrode 134 is formed directly on the insulating substrate 100, and that the Cr film is used for the anode electrode 134. Materials and structures were the same as those of the display device according to the present embodiment in which the characteristics were compared.

As is clear from the graph shown in FIG. 15, at the same current injection density, the display device according to the present embodiment has about twice the luminance of the display device using the Cr film for the anode electrode 134 shown in FIG. 16. It is obtained. Therefore, according to the display device according to the present embodiment in which the light reflection film 72 is formed with the light transmissive insulating layer 74 interposed between the anode electrode 76 made of the transparent conductive film, the Cr film is simply used as the anode electrode. Compared with the case of this, it can be said that light emission efficiency can be improved effectively.

In addition, like the display device according to the first embodiment, in the display device according to the present embodiment, the organic electroluminescent layer 18 is an anode made of a transparent conductive film, as in the conventional organic electroluminescent element. It is formed on the electrode 76. For this reason, as the organic electroluminescent layer 18, the organic electroluminescent layer of the same material and structure as the conventional organic electroluminescent element is used as it is, and the top emission type display device which has high luminous efficiency is comprised. can do.

In the display device according to the present embodiment, an insulating layer 74 is interposed between the anode electrode 76 made of a transparent conductive film and the light reflection film 72 made of an Al film. It is covered by the insulating layer 74 so that the surface is not exposed. Therefore, like the display device according to the first embodiment, when patterning the ITO film in the manufacturing process, it is possible to prevent corrosion due to the battery effect of the light reflection film 72 made of the Al film.

In addition, an insulating layer 74 is formed between the light reflection film 72 made of Al film and the anode electrode 76 made of transparent conductive film. For this reason, as in the case of using an anode electrode in which an ITO film is directly formed on an Al film, whiskers that cause short circuits between the electrodes are generated due to heat generation during application of the driving voltage to the organic electroluminescent element. none.

Next, the manufacturing method of the display device by this embodiment is demonstrated using FIG. 17 and FIG.

First, an Al film having a film thickness of 150 nm is formed on the insulating substrate 10 made of a glass substrate, for example, by a sputtering method. If necessary, the Al film may be patterned into a predetermined shape for each pixel by photolithography and etching. Alternatively, the Al film may remain on the entire surface of the insulating substrate 10 serving as the display region in which the pixels are arranged. In this way, the light reflection film 72 which consists of Al films is formed on the insulating substrate 10 (refer FIG. 17A).

Next, the acrylic photosensitive resin is apply | coated on the light reflection film 72, for example by the spin coat method. Subsequently, after apply | coating the photosensitive resin apply | coated using a predetermined | prescribed mask, the exposed photosensitive resin is developed using a predetermined | prescribed developing solution. In this way, the insulating layer 74 which consists of photosensitive resin with a film thickness of 3.0 micrometers, for example is formed by photolithography (refer FIG. 17B). Here, the insulating layer 74 is formed so as to cover the light reflection film 72 so that the surface of the light reflection film 72 is not exposed.

In this embodiment, since the insulating layer 74 is formed of photosensitive resin, the insulating layer 74 which has the surface with high flatness can be obtained, and an organic electroluminescent element is formed on the surface with high flatness. Can be formed.

Subsequently, an ITO film 78 having a film thickness of 70 nm, for example, is formed on the insulating layer 74 by the sputtering method (see FIG. 17C).

Subsequently, the ITO film 78 is patterned into a predetermined shape by photolithography and etching. In this way, the anode electrode 76 which consists of the ITO film 78 is formed on the insulating layer 74 (refer FIG. 18A). During the patterning of the ITO film 78, the light reflection film 72 made of the Al film is covered by the insulating layer 74, and the surface thereof is not exposed. Therefore, corrosion of the light reflection film 72 due to the battery effect can be prevented.

Subsequently, a 2-TNATA film having a thickness of 140 nm, for example, is deposited on the insulating layer 74 on which the anode electrode 76 is formed, with a deposition mask opened to a predetermined size by, for example, vacuum deposition. For example, an α-NPD film having a thickness of 10 nm, for example, an Alq ₃ film having a thickness of 30 nm, for example an Alq ₃ film having a thickness of 20 nm, for example, doped with a small amount of t (npa) py For example, a LiF film of 0.5 nm is sequentially formed.

In this manner, the anode 76 on, a light emitting layer composed of a 2-TNATA film hole injection layer, a hole transport layer, Alq ₃ film doped with t (npa) py made of α-NPD film comprising, consisting of Alq ₃ film The organic electroluminescent layer 18 which has an electron carrying layer and the electron injection layer which consists of a LiF film is formed (refer FIG. 18B).

Subsequently, on the organic electroluminescent layer 18, for example, an Al film having a film thickness of 1.5 nm, for example, having a mask opened in a predetermined shape by a vacuum deposition method and a sputtering method, for example. For example, an Ag film having a thickness of 15 nm, for example, an ITO film having a thickness of 35 nm is sequentially formed to form an Al / Ag / ITO laminated film.

In this way, the cathode electrode 20 which consists of Al / Ag / ITO laminated film is formed (refer FIG. 18C).

In this way, the display device shown in FIG. 14 is manufactured.

As described above, according to the present embodiment, in the display device using the organic electroluminescent element, under the anode electrode 76 made of a transparent conductive film, the light reflectivity is interposed between the insulating layers 74 having light transparency. Since the light reflection film 72 to be provided is formed, a top emission display device having high light emission efficiency can be realized.

In addition, since the light reflection film 72 is covered by the insulating layer 74, deterioration of device characteristics due to corrosion of the light reflection film 72 and the like can be suppressed.

In addition, since the organic electroluminescent layer 18 is formed on the anode electrode 76 made of a transparent conductive film like the conventional organic electroluminescent element, it is conventionally used as the organic electroluminescent layer 18. The organic electroluminescent layer of the same material and structure as the organic electroluminescent element of can be used as it is.

Also in the display device according to the present embodiment, as in the case of the display device according to the third embodiment, an area in which the light reflection film 72 is formed and an area in which the light reflection film 72 is not formed are formed in the same pixel. That is, by partially forming the light reflection film 72 in the light emitting region where the anode electrode 76 and the cathode electrode 20 overlap, the top emission region and the double-side emission region may be formed in the same pixel.

In addition, as in the case of the display device according to the fourth embodiment, a light reflective film 72 and an insulating layer are formed on the insulating substrate 10 on which the smooth irregularities are formed on the surface of the insulating substrate 10 and the smooth irregularities are formed. 74) and an organic electroluminescent element may be formed. Or you may form smooth unevenness | corrugation on the surface of the insulating layer 74, and may form an organic electroluminescent element on the insulating layer 74 in which smooth unevenness was formed. Smooth unevenness formed on the surface of the insulating substrate 10 or the insulating layer 74 makes the anode electrode 76, the organic electroluminescent layer 18, and the cathode electrode similar to the display device according to the fourth embodiment. The area of the 20 is larger than that of the case where the uneven surface is formed on the insulating substrate 10 on the flat surface, whereby unevenness is formed, and the light emission efficiency can be further improved.

(7th Embodiment)

A display device according to a seventh embodiment of the present invention will be described with reference to FIGS. 19 to 22. 19 is a cross-sectional view showing the structure of the display device according to the present embodiment, and FIGS. 20 to 22 are process cross-sectional views showing the manufacturing method of the display device according to the present embodiment. In addition, about the component, such as the display apparatus by 5th and 6th embodiment shown in FIG. 10, 12-14, 17, and 18, and its manufacturing method, the same code | symbol is attached | subjected and description is abbreviate | omitted or Keep it simple.

In the display device according to the present embodiment, a thin film transistor is formed as a switching element like the display device according to the fifth embodiment together with an organic electroluminescent element like the display device according to the sixth embodiment. An active matrix display device for controlling a driving voltage applied to an organic electroluminescent element by a transistor. Hereinafter, the structure of the display device according to the present embodiment will be described with reference to FIG. 19. 19 shows a structure for one pixel, but a plurality of pixels are actually arranged in a matrix.

On the insulating substrate 10 made of a glass substrate, as in the display device according to the fifth embodiment, a source region formed in the gate electrode 52 and the channel layer 48 with a buffer layer 46 made of a silicon oxide film interposed therebetween. A thin film transistor having a 54 and a drain region 56 and controlling a driving voltage applied to the organic electroluminescent element is formed.

An interlayer insulating film 58 is formed on the insulating substrate 10 on which the thin film transistor is formed. On the interlayer insulating film 58, the source electrode 62 connected to the source region 54 with the contact hole 60 therebetween, and the drain electrode connected to the drain region 56 with the contact hole 64 interposed therebetween ( 66) are formed respectively.

An interlayer insulating film 80 is formed on the interlayer insulating film 58 on which the source electrode 62 and the drain electrode 66 are formed.

On the interlayer insulating film 80, a light reflecting film 72 made of an Al film having light reflectivity is formed. In the light reflection film 72, an opening 82 for exposing a region on the thin film transistor of the interlayer insulating film 80 is formed. In addition, the opening 82 formed in the light reflection film 72 does not necessarily need to expose a region in which the thin film transistor of the interlayer insulating film 80 is formed, and at least a region on the source electrode 62 of the interlayer insulating film 80. It is enough to expose. The light reflection film 72 having such an opening 82 may have a predetermined shape for each pixel, or may be formed on the entire surface of the display area where the pixels are arranged.

On the interlayer insulating film 80 exposed from the light reflection film 72 and the opening 82, an insulating layer 74 made of a photosensitive resin having light transparency is formed. As photosensitive resin which is a material of the insulating layer 74, acrylic resin is used, for example. The insulating layer 74 is formed so as to cover the light reflection film 72 so that the surface of the light reflection film 72 is not exposed.

In the insulating layer 74 and the interlayer insulating film 80, a contact hole 70 reaching the source electrode 62 is formed.

On the insulating layer 74 in which the contact hole 70 was formed, the anode electrode 76 which consists of an ITO transparent conductive film which has a light transmittance is formed in the area | region containing the contact hole 70. As shown in FIG. The anode electrode 76 is electrically connected to the source electrode 62 of the thin film transistor with the contact layer 70 formed in the insulating layer 74 and the interlayer insulating film 80 interposed therebetween.

On the anode electrode 76, an organic electroluminescent layer 18 formed by sequentially laminating a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer is formed. On the organic electroluminescent layer 18, a transparent conductive film composed of an Al film having a thin film thickness and having a light transmittance, an Ag film having a thin film thickness and having a light transparency and an ITO film having light transparency is sequentially laminated. The formed cathode electrode 20 is formed. In this way, the organic electroluminescent element which has the anode electrode 76, the organic electroluminescent layer 18, and the cathode electrode 20 between the insulating layers 74 on the light reflection film 72 is Formed.

In the display device according to the present embodiment, the insulating substrate 10 and the light reflecting film 72 are formed under the anode electrode 76 made of a transparent conductive film with the light transmissive insulating layer 74 interposed therebetween. It is a top emission type from which light is taken out from the cathode electrode 20 side on the opposite side. Therefore, the light emitting area is not limited by the thin film transistor formed on the insulating substrate 10, and high light emission efficiency can be realized.

In addition, in the display device according to the present embodiment, an opening electrode 82 exposing at least the region on the source electrode 62 of the interlayer insulating film 80 is formed in the light reflection film 72, and the anode electrode (made of a transparent conductive film) 76 is directly connected to the source electrode 62 with this contact hole 70 interposed therebetween. As a result, organic electroluminescence is carried out from the light reflection film 72 electrically connected to the source electrode 62 of the thin film transistor without interposing a conductive film that is difficult to secure an electrical connection with the anode electrode 76. May be injected into layer 18. Moreover, since the insulating layer 74 is formed so that the light reflection film 72 may be covered, corrosion of the light reflection film 72 can be prevented. As the organic electroluminescent layer 18, an organic electroluminescent layer of the same material and structure as the organic electroluminescent layer of the conventional organic electroluminescent element can be used as it is.

In addition, when forming the light reflection film 72 which has a predetermined shape for every pixel, it is preferable to form the light reflection film 72 more broadly than the light emitting area | region which the anode electrode 76 and the cathode electrode 20 overlap. . Thus, by forming the light reflection film 72 widely, it can suppress that the light emission of an organic electroluminescent element affects the characteristic of a thin film transistor.

Next, the manufacturing method of the display device which concerns on this embodiment is demonstrated using FIGS. 20-22.

First, a thin film transistor, a source electrode 62 and a drain electrode 66 are formed on the insulating substrate 10 in the same manner as the manufacturing method of the display device according to the fifth embodiment shown in FIGS. 12A to 12C and 13A. To form (see FIG. 20A).

Subsequently, an interlayer insulating film 80 made of, for example, a silicon oxide film having a thickness of 300 nm is formed on the interlayer insulating film 58 on which the source electrode 62 and the drain electrode 66 are formed, for example, by the CVD method. (See FIG. 20B). In addition to the silicon oxide film, an insulating film made of an inorganic insulating film such as a silicon nitride film and a resin can be used for the interlayer insulating film 80.

Subsequently, an Al film 84 having a thickness of 150 nm, for example, is formed on the interlayer insulating film 80 by, for example, a sputtering method.

Subsequently, by lithography, the Al film 84 is patterned into a predetermined shape to form an opening 82 in the Al film 84 that exposes at least a region on the source electrode 62 of the interlayer insulating film 80. . The Al film 84 may be patterned so as to have a predetermined shape for each pixel, or may be left on the entire surface of the display area in which the pixels are arranged.

In this way, the light reflection film 72 which consists of Al films 84 is formed (refer FIG. 21A). In addition, in FIG. 21A, the case where the opening part 82 which exposes the area | region on the thin film transistor of the interlayer insulation film 80 is formed in the light reflection film 72 is shown.

Subsequently, on the interlayer insulating film 80 exposed from the light reflection film 72 and the opening 82, a photosensitive resin is applied by, for example, a spin coating method to form a photosensitive resin layer 86 (FIG. 21B). Reference).

After exposing the photosensitive resin layer 86 using a predetermined mask, the exposed photosensitive resin layer 86 is developed using a predetermined developer to expose a region on the source electrode 62 of the interlayer insulating film 80. The openings 88 to be formed are formed in the photosensitive resin layer 86. In this way, the insulating layer 74 which consists of the photosensitive resin layer 86 which has the light transmittance with the opening part 88 formed by photolithography is formed (refer FIG. 21C). Here, the insulating layer 74 is formed so as to cover the light reflection film 72 so that the surface of the light reflection film 72 is not exposed.

Subsequently, the opening 90 reaching the source electrode 62 is formed in the interlayer insulating film 80 using the insulating layer 74 having the opening 88 formed thereon as a mask, for example, by dry etching.

In this way, the contact hole 70 formed by the opening 90 formed in the interlayer insulating film 80 and the opening 88 formed in the insulating layer 74 is formed (see FIG. 22A). In addition, in order to prevent the light reflection film 72 from being exposed to the contact hole 70, the size of the opening 82 of the light reflection film 72, the size of the opening 88 of the insulating layer 74, etching conditions, and the like are appropriately selected in advance. It is preferable to set. This is based on the following reasons. That is, when the light reflection film 72 is exposed to the contact hole 70, the anode electrode 76 and the light reflection film 72 formed thereafter contact and the parasitic capacitance is formed therebetween. This is to avoid deterioration of device characteristics due to this.

Thus, in the manufacturing method of the display apparatus by this embodiment, since the insulating layer 74 is formed of photosensitive resin and the insulating layer 74 is used also as a mask at the time of etching the interlayer insulating film 80, Up to the contact holes 70 can be formed with a small number of processes. As the insulating layer 74, an inorganic insulating film having light transmittance such as a silicon oxide film can also be used. In this case, in addition to the process of forming the insulating layer 74 which consists of an inorganic insulating film, the resist film used as an etching mask for forming the contact hole 70 in the insulating layer 74 and the interlayer insulating film 80 is formed. A process and a process of removing a resist film are also required. For this reason, compared with the case where the insulating layer 74 is formed by the photosensitive resin, process number increases.

Subsequently, the anode connected to the source electrode 62 with the contact hole 70 interposed therebetween in the same manner as in the manufacturing method of the display device according to the sixth embodiment on the insulating film 74 having the contact hole 70 formed thereon. The electrode 76, the organic electroluminescent layer 18, and the cathode electrode 20 are formed (see FIG. 22B).

In this way, the display device by this embodiment shown in FIG. 19 is manufactured.

As described above, according to the present embodiment, in the display device using the organic electroluminescent element, under the anode electrode 76 made of a transparent conductive film, the light reflectivity is interposed between the insulating layers 74 having light transparency. Since the light reflecting film 72 is formed, a top emission display device having a high luminous efficiency can be realized without being limited by the thin film transistor formed under the organic electroluminescent element.

In addition, since the light reflection film 72 is covered by the insulating layer 74, deterioration of device characteristics due to corrosion of the light reflection film 72 and the like can be suppressed.

In addition, since the organic electroluminescent layer 18 is formed on the anode electrode 76 made of a transparent conductive film like the conventional organic electroluminescent element, the organic electroluminescent layer 18 is conventionally used as an organic electroluminescent layer 18. The organic electroluminescent layer of the same material and structure as the organic electroluminescent element of can be used as it is.

(Modification embodiment)

The present invention is not limited to the above embodiments, and various modifications are possible.

For example, in the said embodiment, although the case where a glass substrate is used as the insulating substrate 10 was demonstrated, the insulating substrate 10 is not limited to a glass substrate. For example, resin films, such as polycarbonate and polyethylene terephthalate, may be used as the insulating substrate 10. By using the resin film as the insulating substrate 10, a flexible flexible display device can be realized. In addition, in the case of configuring only the top emission display device, the insulating substrate 10 does not necessarily need to be light-transmitting like a glass substrate. However, as in the case of the display device according to the third embodiment, in the case where the top light emitting portion 40 and the double-sided light emitting portion 44 are formed on the same substrate, the substrate having the light transmittance may be formed on the insulating substrate 10. It needs to be used as.

In addition, in the said embodiment, although the case where the interposition film 30 was formed on the periphery of the light reflection film 12 was demonstrated, the interposition film 30 must necessarily be formed on the periphery of the light reflection film 12. It is only necessary to form it partially on the predetermined region of the light reflection film 12.

In addition, in the said embodiment, although the case where Al film was used as the light reflection film 12 and 72 for reflecting the light which generate | occur | produced in the light emitting layer of the organic electroluminescent layer 18 to the cathode electrode 20 side was demonstrated. , Light reflection films 12 and 72 are not limited to Al films. As the light reflection films 12 and 72, in addition to an alloy containing Al or Al as a main component, for example, Ag, Nd (neodymium), Si (silicon), Ti, W (tungsten), Cu (copper), Nb (niobium) ), Ta (tantalum), C (carbon), or a conductive film having light reflectivity made of an alloy containing at least any one of them can be used.

In addition, in the said embodiment, Mo film | membrane is used as the interposition film 30 for improving the electrical connection of the light reflection film 12 which consists of Al films, and the transparent conductive film 14 which consists of ITO films, and ensures the conduction between them. Although the case where it was mentioned was demonstrated, the interposition film 30 is not limited to Mo film | membrane. As the interlayer film 30, in addition to an alloy containing Mo or Mo as a main component, for example, a conductive film made of a high melting point metal such as W, Ta, Ti, Cr, or an alloy containing at least any one of them as a main component may be used. Can be.

In addition, in the said embodiment, although the case where an ITO film was used as the transparent conductive film 14 and the anode electrode 76 formed on the light reflection film 12 was demonstrated, the transparent conductive film 14 and the anode electrode 76 were demonstrated. ) Is not limited to the ITO film. As the transparent conductive film 14, in addition to the ITO film, for example, a conductive film having light transmittance such as an IZO (zinc-doped indium oxide) film or a ZnO (zinc oxide) film can be used.

In the above embodiment, the organic electroluminescent layer 18 includes a hole injection layer made of a 2-TNATA film, a hole transport layer made of an α-NPD film, and an Alq ₃ film doped with t (npa) py. a light emitting layer, has been described as to the case of using the formed electron injection layer made of an electron transport layer, LiF film made of Alq ₃ film are sequentially laminated, structure and material of the organic electroluminescence layer 18 is limited to this It is not. As the structure of the organic electroluminescent layer 18, a single layer structure of only the light emitting layer, a two-layer structure of a hole transporting layer and a light emitting layer or a light emitting layer and an electron transporting layer, and a three-layer structure of a hole transporting layer, a light emitting layer and an electron transporting layer can be applied. In addition, all organic electroluminescent materials can be used as a material of the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, and the electron injection layer which comprise the organic electroluminescent layer 18.

In the above embodiment, the case where the Al / ITO laminated film and the Al / Ag / ITO laminated film is used as the cathode electrode 20 has been described. However, the cathode electrode 20 includes the Al / ITO laminated film and Al / Ag /. It is not limited to an ITO laminated film. As the cathode electrode 20, in addition to the Al / ITO laminated film and the Al / Ag / ITO laminated film, for example, an ITO single film, an IZO film, a ZnO film, an Al single film, an Ag single film, or a laminated film thereof may have a light transmissive property. A conductive film can be used. In addition, when Al film | membrane, Ag film | membrane, etc. are used as the cathode electrode 20, these films need to be formed thin so that it may have light transmittance.

In addition, in the said embodiment, although the case where the thing which consists of photosensitive resin is used as the insulating layer 74 was demonstrated, if the insulating layer 74 has a light transmittance, it is not limited to what consists of photosensitive resin. As the insulating layer 74, in addition to the photosensitive resin, an inorganic insulating film having light transmittance such as a silicon oxide film, a silicon nitride film, and a silicon nitride oxide film can be used. In addition, as long as the insulating layer 74 has light transmittance, it is not necessary to be colorless. As the insulating layer 74, what consists of colored resins, such as polyimide, can also be used.

Moreover, in the said embodiment, although the case where the top gate type was used as a thin film transistor was demonstrated, you may use a bottom gate type as a thin film transistor. Moreover, although the case where a polysilicon film is used for the channel layer 48 was demonstrated, you may use an amorphous silicon film for the channel layer 48. As shown in FIG.

Moreover, in the said embodiment, although the case where a thin film transistor was used as a switching element was demonstrated, you may use another switching element. For example, you may use the switching element of the MIM (metal-insulation film-metal) structure using the diode which is a 2-terminal element.

An organic electroluminescent element, a method for manufacturing the same, and a display device according to the present invention realize an organic electroluminescent element, a method for producing the same, and a display device using the organic electroluminescent element, which are excellent in light emission efficiency. Therefore, while being excellent in display characteristics, it is useful for the application to the display device which is low power consumption.

Claims (23)

An anode having a first conductive film formed on a substrate and covering the first conductive film on the first conductive film, the anode having a second conductive film having light transparency; An organic electroluminescent layer formed on the anode electrode, and It is formed on the said organic electroluminescent layer, and has an organic electroluminescent element characterized by having the cathode which has light transmittance. A first conductive film formed on the substrate and having a light reflectivity, a second conductive film formed on the first conductive film and having a light transmittance, and partially formed between the first conductive film and the second conductive film; An anode having a third conductive film electrically connected to each of the first conductive film and the second conductive film, An organic electroluminescent layer formed on the anode electrode, and An organic electroluminescent device, characterized in that it has a cathode electrode formed on said organic electroluminescent layer and having light transmittance. The method of claim 2, The said 3rd conductive film is formed on the periphery of the said 1st conductive film, The organic electroluminescent element characterized by the above-mentioned. The method of claim 2, The said 2nd conductive film is formed so that the said 1st conductive film may be covered. The organic electroluminescent element characterized by the above-mentioned. The method of claim 2, And said third conductive film is made of a high melting point metal. The method of claim 5, The said 3rd conductive film is Mo, W, Ta, Ti, Cr, or the organic electroluminescent element characterized by the alloy which has at least any one of these as a main component. A first conductive film formed on the substrate and having light reflectivity, An insulating layer formed on the first conductive film and having light transmittance; An anode having a second conductive film formed on the insulating layer and having light transmittance; An organic electroluminescent layer formed on the anode electrode, and An organic electroluminescent device, characterized in that the organic electroluminescent device formed on the organic electroluminescent layer has a light-transmitting cathode. The method of claim 7, wherein The said insulating layer is formed so that the said 1st conductive film may be covered. The organic electroluminescent element characterized by the above-mentioned. The method of claim 7, wherein An organic electroluminescent element, wherein said first conductive film is formed wider than a light emitting region in which said anode electrode and said cathode electrode overlap. The method of claim 7, wherein The film thickness of the said insulating layer is 1 micrometer or more, The organic electroluminescent element characterized by the above-mentioned. The method of claim 7, wherein The light transmittance of the said insulating layer is 50% or more, The organic electroluminescent element characterized by the above-mentioned. The method of claim 1, The first conductive film is partially formed in a light emitting region in which the anode electrode and the cathode electrode overlap with each other. The method of claim 1, An unevenness is formed in the surface of the said board | substrate or the said insulating layer, The organic electroluminescent element characterized by the above-mentioned. The method of claim 1, The first conductive film is made of Al, Ag, Nd, Si, Ti, W, Cu, Nb, Ta, C, or an alloy containing at least one of them as a main component. The method of claim 1, The second conductive film is made of ITO, IZO, or ZnO. The organic electroluminescent device characterized by the above-mentioned. A display apparatus comprising the organic electroluminescent element according to claim 1 in a pixel region. The method of claim 16, And a switching element formed on the substrate to control a driving voltage applied to the organic electroluminescent element. Forming an anode electrode having a first conductive film having a light reflectivity on a substrate and a second conductive film formed on the first conductive film so as to cover the first conductive film; Forming an organic electroluminescent layer on the anode, and A method for producing an organic electroluminescent device, comprising the step of forming a cathode electrode having light transmittance on the organic electroluminescent layer. The method of claim 18, In the step of forming the anode electrode, before forming the second conductive film, a third conductive film electrically connected to each of the first conductive film and the second conductive film is partially formed on the first conductive film. The manufacturing method of the organic electroluminescent element characterized by the above-mentioned. The method of claim 19, The step of forming the anode electrode includes forming the third conductive film on the first conductive film, forming a resist film on the third conductive film, and partially forming a thick foil in the film thickness of the resist film. Process, etching the third conductive film and the first conductive film using the resist film having a thick film formed thereon as a mask; removing a thin portion of the resist film and forming an opening in the resist film. And etching the third conductive film exposed at the bottom of the opening as a mask using the resist film having the opening formed as a mask, thereby forming the third conductive film partially on the first conductive film. The manufacturing method of the organic electroluminescent element made into. The method of claim 20, In the step of partially forming a thick foil in the film thickness of the resist film, a thick foil is formed in a film thickness of the resist film by partially changing the exposure amount of the resist film. The method of claim 19, In the step of partially forming the third conductive film, the third conductive film is formed on the periphery of the first conductive film. Forming a switching element on the substrate, Forming a first insulating layer on the substrate on which the switching element is formed; Forming a first conductive film having light reflectivity on the first insulating layer, Forming a second insulating layer made of a photosensitive resin having a first opening on the electrode of the switching element, on the first insulating layer having the first conductive film formed thereon, Etching the first insulating layer using the second insulating layer as a mask, and forming a second opening portion reaching the electrode of the switching element, Forming an anode on the second insulating layer, the anode having a second conductive film having optical transparency, electrically connected to an electrode of the switching element with the first opening and the second opening interposed therebetween, Forming an organic electroluminescent layer on the anode, and And forming a cathode electrode having a light transmissivity on the organic electroluminescent layer.

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