JP2003068459A - Organic electroluminescence panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable that an organic EL is not deteriorated due to generation of a crack or the like in a light-emitting layer formed on the organic EL panel and that housing and transportation or the like of the organic EL panel are easily carried out in the case the organic EL panel is wound up or folded by using a flexible one as a substrate in the organic EL panel in which a drive electrode driven by a thin-film transistor is installed on the substrate. SOLUTION: In this organic EL panel, plural numbers of drive electrodes 6 driven via the thin-film transistor 1 by an outside signal are installed on the substrate 10, and when at least counter electrodes 14 opposing the light- emitting layer 12 and the drive electrodes using at least an organic material are made laminated on this substrate, the light-emitting layers are separated corresponding to respective drive electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence panel used for a display or the like, and particularly, in an organic electroluminescence panel driven by a thin film transistor, even when the organic electroluminescence panel is bent, The present invention relates to an organic electroluminescence panel which can be easily stored and transported without damaging a light emitting layer provided in the organic electroluminescence panel.

[0002]

2. Description of the Related Art In recent years, along with the diversification of information equipment, the need for a flat display device that consumes less power and occupies less space than a CRT that has been generally used has been increased, and such a flat display device is required. As one of the above, an electroluminescence element (hereinafter, abbreviated as EL element) is receiving attention.

The EL element is roughly classified into an inorganic EL element and an organic EL element depending on the material used.
In the element, a high electric field is generally applied to the light emitting portion, electrons are accelerated in the high electric field to collide with the emission center, and thereby the emission center is excited to emit light. In, the electrons and holes are injected into the light emitting part from the electron injection electrode and the hole injection electrode, respectively, and the electrons and holes thus injected are recombined at the emission center to excite the organic material. The organic material emits fluorescence when the organic material returns from the excited state to the ground state.

Here, in the case of an inorganic EL element, since a high electric field is applied as described above, its driving voltage is 100
In contrast to requiring a high voltage of up to 200 V, the organic EL element described above has the advantage that it can be driven at a low voltage of approximately 5 to 20 V.
Various studies have been conducted on devices.

In order to use such an organic EL element in a display or the like, it has been studied to manufacture an organic EL panel composed of a plurality of pixels, and in the past, a simple matrix type display was proposed. .

Here, in the conventional simple matrix type display, a plurality of linear hole injecting electrodes corresponding to the scanning lines are provided on the substrate at a required interval, and thus a plurality of linear holes are formed. A light emitting layer, a charge transport layer, etc. are formed on the substrate on which the injection electrodes are formed, and linear electron injection electrodes corresponding to the signal lines are formed on the substrate at a predetermined interval so as to be orthogonal to the above hole injection electrodes. I was trying to provide a plurality through.

When an electron injection electrode having an appropriate pattern is provided on the light emitting layer, the charge transport layer, etc. as described above,
Generally, photolithography and mask vapor deposition are used. However, since the light emitting layer and the charge transport layer have low resistance to moisture and organic solvents, if an electron injection electrode with an appropriate pattern is provided by photolithography, the light emitting layer and the charge transport layer are There is a problem that layers and the like are deteriorated, and when an electron injection electrode having an appropriate pattern is formed by mask vapor deposition, it is difficult to process a fine pattern.

Therefore, in recent years, when manufacturing an organic EL panel composed of a plurality of pixels used for a display or the like, as disclosed in JP-A-7-111341 and JP-A-8-54836. In addition, a drive electrode driven by a thin film transistor is provided on the substrate corresponding to each pixel, and the drive electrode at an appropriate position is driven by the thin film transistor so that the organic EL in a portion corresponding to the drive electrode is caused to emit light. Was developed.

Here, the organic EL devices disclosed in these publications
In the panel, the light emitting layer is continuously formed on the substrate on which the drive electrodes driven by the thin film transistors are provided corresponding to the respective pixels.

Therefore, the organic E shown in these publications is used.
When a flexible substrate is used as the substrate of the L panel and the organic EL panel is wound or bent,
There is a problem that cracks and the like occur in the light emitting layer formed on this substrate, the organic EL is deteriorated, and stable light emission cannot be performed.

[0011]

SUMMARY OF THE INVENTION The present invention is an organic EL device.
It is an object of the present invention to solve the above-mentioned various problems in a panel, and in particular, a drive electrode driven by a thin film transistor is provided on a substrate corresponding to each pixel, and a drive electrode at an appropriate position is provided in the thin film transistor. In the organic EL panel which is driven by, and emits the organic EL in the portion corresponding to the drive electrode, a flexible substrate is used for the organic EL panel, and the organic EL panel is wound up. Even when the organic EL panel is bent, the light emitting layer formed on the organic EL panel will not be cracked and the organic EL will not be deteriorated, and the organic EL panel can be easily stored and transported. The task is to do so.

[0012]

SOLUTION TO THE PROBLEM Organic E in the present invention
In the L panel, in order to solve the above problems, a plurality of drive electrodes driven via thin film transistors by an external signal are provided on a substrate, and a light emitting layer using at least an organic material and the above When laminating the counter electrode facing the drive electrode, the light emitting layer is separated corresponding to each drive electrode.

Here, like the organic EL panel of the present invention, a plurality of drive electrodes driven by thin film transistors by an external signal are provided on a substrate, and a light emitting layer made of at least an organic material and the above-mentioned substrate are provided on the substrate. If a counter electrode facing the drive electrode of is laminated, it is easy to apply a voltage between the drive electrode and the counter electrode at an appropriate position by the thin film transistor to cause the light emitting layer to emit light at the appropriate position. In addition to the conventional method, it is not necessary to pattern the counter electrode by photolithography, mask vapor deposition or the like as in the conventional case.

When the light emitting layer is separated corresponding to each drive electrode like the organic EL panel in the present invention, a flexible substrate is used for the above substrate and the organic EL panel is wound up. When it is bent or bent, the light emitting layer is less likely to be cracked. In particular, by bending the organic EL panel at a portion where the light emitting layer is not provided, the organic EL panel can be made compact without damaging the light emitting layer. You will be able to.

When the organic EL is driven by the thin film transistor as described above, a latch-up circuit or the like is added to the thin film transistor,
Various controls can be easily performed on each pixel of the organic EL panel.

Here, the organic EL element structure in the organic EL panel of the present invention is referred to as a DH structure in which a hole transporting layer, a light emitting layer and an electron transporting layer are laminated between a hole injecting electrode and an electron injecting electrode. A three-layer structure, a two-layer structure called a SH-A structure in which a hole-transporting layer and an electron-transporting light-emitting layer are stacked between a hole-injecting electrode and an electron-injecting electrode, and hole-injecting SH-B in which a hole-transporting light-emitting layer and an electron-transporting layer are laminated between an electrode and an electron-injecting electrode
It may have any of the two-layer structure called a structure.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An organic EL panel according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings.

In the organic EL panel according to this embodiment, a flexible resin substrate 10 having excellent heat resistance is used.
1 is used, the thin film transistor 1 is provided on the substrate 10 as shown in FIGS.

Here, the thin film transistor 1 is formed on the substrate 10.
In providing, a plurality of gate electrodes 3 are connected to the electrode lines 2x in the X direction, and a plurality of source electrodes 4 are connected to the electrode lines 2y in the Y direction.
An amorphous silicon layer 5 was connected to each source electrode 4.

Then, for each amorphous silicon layer 5 connected to the source electrode 4 in this manner, for each drive electrode 6
I was made to connect.

In this thin film transistor 1,
When a voltage is applied to the appropriate X-direction electrode line 2x and Y-direction electrode line 2y, the drive electrode 6 at the intersection becomes equipotential with the Y-direction electrode line 2y via the amorphous silicon layer 5.

In the organic EL panel of this embodiment, as shown in FIG. 2, in the thin film transistor 1 having the above-mentioned structure, the above-mentioned electrode lines 2x, 2 are formed.
y, each gate electrode 3, each source electrode 4, and each amorphous silicon layer 5 were all covered with the insulating film 7, and only the drive electrode 6 was exposed. In this embodiment, the drive electrode 6 is used as an electron injection electrode, and a magnesium-indium alloy or the like is used as the electrode material.

Next, after the electron transport layer 11 is formed on the substrate 10 on which the thin film transistor 1 and the drive electrodes 6 connected to the thin film transistor 1 are provided in this manner,
The electron transport layer 11 is irradiated with a laser beam, and the electron transport layer 11 is separated so as to correspond to each drive electrode 6, as shown in FIG.
Was formed. As a material forming the electron transport layer 11, a commonly used electron transport material can be used, and for example, an oxadiazole derivative [tBu-PBD] shown in Chemical Formula 1 below can be used. .

[0024]

[Chemical 1]

The substrate 10 on which the electron transport layer 11 is separately formed so as to correspond to each drive electrode 6 in this way
After forming the light emitting layer 12 on the upper surface, the light emitting layer 12 is irradiated with a laser beam to separate the light emitting layer 12 so as to correspond to the drive electrodes 6 as shown in FIG. A light emitting layer 12 was formed so as to cover each electron transport layer 11 formed above. As the material for forming the light emitting layer 12, a generally used organic light emitting material can be used. For example, tris (8-hydroxyquinoline) aluminum [Alq3] shown in Chemical formula 2 below can be used. In addition, in the charge transporting host material,
Alternatively, a light emitting material such as rubrene shown in 1 may be doped.

[0026]

[Chemical 2]

[0027]

[Chemical 3]

Then, the substrate 1 on which the light emitting layer 12 is separated so as to correspond to the respective drive electrodes 6 is formed.
0, as shown in FIG. 5, the hole transport layer 13 was formed without separating, and the hole injecting electrode was formed as the counter electrode 14 on the hole transport layer 13 without separating. Even in the case where the hole transport layer 13 is thus formed without being separated, in this embodiment, the light emitting layer 12 is formed so as to cover each electron transport layer 11 as described above. Therefore, the hole transport layer 13 does not come into contact with the electron transport layer 11.

Here, as the material for forming the hole transport layer 13, a generally used hole transport material can be used. For example, N, N'-diphenyl-N, N'- shown in the following chemical formula 4 is used. Bis (3-methylphenyl) -1,
A triphenylamine derivative such as 1'-biphenyl-4,4'-diamine [TPD] or a hydrazone derivative can be used.

[0030]

[Chemical 4]

Further, transparent ITO is used for the counter electrode 14 used as the hole injecting electrode.

Then, in the organic EL panel of this embodiment, when a voltage is applied between the drive electrode 6 and the counter electrode 14 at an appropriate position by the thin film transistor 1 formed on the substrate 10, the drive electrode 6 is applied to the drive electrode 6. The light emitting layer 12 in the corresponding position emitted light, and this light came to be emitted from the counter electrode 14 made of the transparent ITO.

In the organic EL panel of this embodiment, the substrate 10 is made of flexible resin as described above, and each light emitting layer 12 is separated so as to correspond to each drive electrode 6. By bending the substrate 10 in a portion where the light emitting layer 12 is not provided,
The organic EL panel can be made compact without damaging the light emitting layer 12, and the organic EL panel can be easily stored and transported.

In the organic EL panel of this embodiment, the hole transport layer 13 is provided on the entire surface of the substrate 10 on which the light emitting layer 12 is formed. However, as shown in FIG. As for the light emitting layer 12, it is also possible to perform processing with a laser beam in the same manner as the light emitting layer 12 to separate the hole transport layer 13 so as to correspond to each drive electrode 6, and thus the hole transport layer 13 is formed separately. In addition, as shown in FIG. 7, the hole injecting electrode can be formed as the counter electrode 14 without separating it.

In the organic EL panel of this embodiment, the drive electrode 6 driven by the thin film transistor 1 is used as the electron injection electrode, while the counter electrode 14 is used as the hole injection electrode. While 6 is made of transparent ITO and used as a hole injecting electrode, the counter electrode 14 may be made of magnesium-indium alloy or the like and used as an electron injecting electrode.

In this case, in order to emit light from the drive electrode 6 side, a transparent substrate is used for the substrate 10 and the hole transport layer 1 is provided on the drive electrode 6.
4, the light emitting layer 13, and the electron transport layer 12 are laminated in this order.

Further, in this embodiment, the electron transport layer 12 and the light emitting layer 1 are provided between the driving electrode 6 and the counter electrode 14.
3 and the example of the organic EL panel having the DH structure in which the hole transport layer 14 is provided, the element structure of this organic EL panel is not limited to such a DH structure.
It may have the above-mentioned SH-A structure or SH-B structure.

[0038]

As described above in detail, in the organic EL panel of the present invention, a plurality of drive electrodes driven by the external signals through the thin film transistors are provided on the substrate, and at least the organic material is provided on the substrate. Since the used light emitting layer and the counter electrode facing the drive electrode are laminated, a voltage is applied between the drive electrode and the counter electrode at an appropriate position by the thin film transistor, and the light emitting layer emits light at the appropriate position. In addition to the fact that it can be easily performed, it is no longer necessary to pattern the counter electrode by photolithography or mask vapor deposition as in the conventional case.

Further, in the organic EL panel of the present invention, since the light emitting layer is separated corresponding to each drive electrode, a flexible substrate is used and the organic EL panel is wound or bent. In this case, the light emitting layer is less likely to be cracked, and in particular, by bending the organic EL panel at the portion where the light emitting layer is not provided, the organic electroluminescence panel can be compacted without damaging the light emitting layer. It can be stored and transported easily.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a state of a thin film transistor formed on a substrate in an organic electroluminescence panel according to an embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory view showing a state in which a thin film transistor and a drive electrode connected to the thin film transistor are provided on a substrate in the same embodiment.

FIG. 3 is a cross-sectional explanatory view showing a state in which an electron transport layer is formed on each drive electrode provided on the substrate in the same embodiment.

FIG. 4 is a cross-sectional explanatory view showing a state in which a light emitting layer is formed on the electron transport layer shown in FIG. 3 in the same embodiment.

FIG. 5 is a cross-sectional explanatory view of the organic electroluminescence panel in which the hole transport layer and the counter electrode are formed on the light emitting layer shown in FIG. 4 in the same embodiment.

FIG. 6 is a cross-sectional explanatory view showing a state in which a hole transport layer is separated so as to correspond to each drive electrode similarly to the light emitting layer in the organic electroluminescence panel in the same embodiment.

FIG. 7 is a cross-sectional explanatory view of the organic electroluminescence panel in which a counter electrode is formed on the hole transport layer shown in FIG. 6 in the same embodiment.

[Explanation of symbols]

1 thin film transistor 2x, 2y electrode wire 3 Gate electrode 4 Source electrode 5 Amorphous silicon layer 6 drive electrode 10 substrates 11 Electron transport layer 12 Light-emitting layer 13 Hall transport layer 14 Counter electrode

Claims (3)

[Claims] 1. A plurality of drive electrodes, which are driven by thin film transistors by an external signal, are provided on a substrate, and a light emitting layer made of at least an organic material and a counter electrode facing the drive electrodes are provided on the substrate. An organic electroluminescence panel, characterized in that the light-emitting layers are laminated and the light-emitting layers are separated corresponding to the respective drive electrodes. 2. The organic electroluminescence panel according to claim 1, wherein a carrier transport layer is formed on the drive electrode, and the light emitting layer is formed so as to cover the carrier transport layer. Characteristic organic electroluminescence panel. 3. The organic electroluminescence panel according to claim 1 or 2, wherein a flexible substrate is used.