JP2005302308A - Organic electroluminescent display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent display device of a simple structure and a high luminous efficiency as well as a simple manufacturing method of the same. <P>SOLUTION: The device is provided with a base plate 1, a transparent first electrode 2 formed on the surface of the base plate 1, a luminous layer 3 laminated on the first electrode 2, and a second electrode 4 laminated on the luminous layer 3, with a concave part 6 formed at a part where light emitted from the luminous layer 3 is transmitted. Further, the concave part 6 is formed in a spherical shape, and the first electrode 2 functions as a lens. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic EL display device and a manufacturing method thereof, and particularly relates to an organic EL display device having a simple structure and high luminous efficiency.

  The conventional organic EL display device has a structure in which a flat glass substrate, an anode, a light emitting layer (also referred to as an organic EL layer) and a cathode are laminated in a flat manner. There is a problem that the external light emission efficiency of the organic EL display device is lowered due to total reflection or the like at the interface between the glass substrate and the glass substrate.

For this reason, in the conventional light emitting element and its manufacturing method, a lens is provided on the upper layer of the electrode separately from the light emitting layer and the electrode, and the light emitted from the light emitting layer is condensed by this lens and emitted to the outside. As a result, there are some which improve the luminous efficiency.
Japanese Patent Laying-Open No. 2003-31353 (FIGS. 1 and 9)

  However, in the conventional light emitting device and the manufacturing method thereof (see, for example, Patent Document 1), a lens for condensing light emitted from the light emitting layer must be provided for each light emitting device, and a minute lens is precisely formed. Therefore, there is a problem that the manufacturing process is complicated and the cost is increased.

  An object of the present invention is to provide an organic EL display device having a simple structure and high luminous efficiency, and a simple manufacturing method of the organic EL display device.

An organic EL display device according to the present invention includes a substrate, a transparent first electrode formed on the surface of the substrate, a light emitting layer stacked on the first electrode, and a second electrode stacked on the light emitting layer. And a recess is formed in a portion of the surface of the substrate through which light emitted from the light emitting layer is transmitted.
Since the concave portion is formed in the portion of the surface of the substrate through which the light emitted from the light emitting layer is transmitted, for example, if the first electrode is formed inside the concave portion to have the function of a lens, the first Reflection of light emitted in an oblique direction at the interface between the electrode and the substrate can be suppressed, and an organic EL display device with high luminous efficiency can be obtained.

In the organic EL display device according to the present invention, the concave portion is formed in a spherical shape, and the first electrode functions as a lens.
Since the concave portion is formed in a spherical shape, and the first electrode formed therein functions as a convex lens, reflection of light emitted in an oblique direction at the interface between the first electrode and the substrate can be suppressed, Since the light condensing effect is also obtained, the light emission efficiency of the organic EL display device can be improved.

In the organic EL display device according to the present invention, the substrate is made of glass.
Since the substrate is made of transparent glass, the light emitted from the light emitting layer can be transmitted outside the system, and the above-mentioned recess can be easily formed with hydrofluoric acid or the like.

In the organic EL display device according to the present invention, the first electrode is filled in the entire interior of the recess, and the surface of the first electrode in contact with the light emitting layer is formed flat.
Since the first electrode is filled in the entire interior of the recess, for example, a convex lens corresponding to the shape of the spherical recess is formed, and reflection of light emitted in an oblique direction at the interface between the first electrode and the substrate is suppressed. be able to. In addition, since the surface of the first electrode in contact with the light emitting layer is formed flat, the light emitting layer and the second electrode can be easily formed.

In the organic EL display device according to the present invention, the surface of the light-emitting layer that contacts the first electrode and the surface that contacts the second electrode are both spherical.
Since both the surface in contact with the first electrode and the surface in contact with the second electrode of the light emitting layer are spherical, light emitted from the light emitting layer is incident at an angle close to a right angle with respect to the surface of the first electrode and the substrate, Light reflection such as total reflection can be suppressed.

In the organic EL display device according to the present invention, the surface of the light emitting layer in contact with the first electrode is formed in a spherical shape, and the surface of the light emitting layer in contact with the second electrode is formed flat.
Since the surface of the light emitting layer in contact with the first electrode is formed in a spherical shape, light emitted from the light emitting layer is incident at an angle close to a right angle with respect to the surface of the first electrode and the substrate, and light such as total reflection Reflection can be suppressed. In addition, since the surface in contact with the second electrode of the light emitting layer is formed flat, the second electrode can be easily formed.

Further, in the organic EL display device according to the present invention, the depression formed in the first electrode is filled with the light emitting layer and the second electrode so that the opening of the depression is flat.
Since the depression formed in the first electrode is filled with the light emitting layer and the second electrode so that the opening of the depression is flat, the first electrode, the light emitting layer, and the second electrode can be formed thin. In addition, the entire organic EL display device can be thinned.

The organic EL display device manufacturing method according to the present invention includes a substrate, a transparent first electrode formed on the surface of the substrate, a light emitting layer stacked on the first electrode, and a layer stacked on the light emitting layer. A method of manufacturing an organic EL display device including a second electrode, the step of forming a spherical recess in a portion of a surface of a substrate through which light emitted from a light emitting layer is transmitted, and the first electrode Forming a step in which at least a part of the first electrode functions as a lens inside the recess, a step of laminating the light emitting layer on the first electrode, and a step of laminating the second electrode on the light emitting layer It is what has.
A spherical concave portion is formed in a portion of the surface of the substrate where light emitted from the light emitting layer is transmitted, and the first electrode functions as a lens on the surface of the substrate and at least a part of the first electrode inside the concave portion. Therefore, since the reflection of light emitted in an oblique direction at the interface between the first electrode and the substrate can be suppressed and a light collecting effect can be obtained, the light emission efficiency of the organic EL display device can be improved. .

In the method for manufacturing an organic EL display device according to the present invention, the step of forming the recess is performed by wet etching.
For example, if a concave portion is formed by isotropic etching by performing wet etching after forming a resist pattern by photolithography, a spherical concave portion can be easily formed.

Moreover, in the method for manufacturing an organic EL display device according to the present invention, the step of forming the recess is performed by dry etching.
For example, if a concave portion is formed by performing dry etching after forming a resist pattern by photolithography, the concave portion can be easily formed in the same manner as the above wet etching.

In the method for manufacturing an organic EL display device according to the present invention, the step of forming the concave portion is performed by sandblasting.
If the recess is formed by sandblasting, the recess can be formed without forming a resist or the like.

In the method for manufacturing an organic EL display device according to the present invention, the step of forming the concave portion is performed by a mechanical cutting means.
If the recess is formed by mechanical cutting means, the recess can be formed without forming a resist or the like.

Embodiment 1. FIG.
1, FIG. 2, FIG. 3 and FIG. 4 are schematic longitudinal sectional views showing the main parts of an organic EL display device according to Embodiment 1 of the present invention. In FIGS. 1 to 4, TFT (Thin Film Transistor) wiring and the like necessary for driving the organic EL display device are omitted.
The organic EL display device shown in FIG. 1 includes a substrate 1 made of glass, a transparent first electrode 2 made of ITO (Indium Tin Oxide), a light emitting layer 3, a second electrode 4, and a partition wall 5. In the organic EL display device according to the first embodiment, the first electrode 2 is a common electrode. The first electrode 2 is formed on the surface of the substrate 1, a plurality of light emitting layers 3 are formed so as to be stacked on the first electrode 2, and a plurality of second electrodes 4 are stacked so as to be stacked on the light emitting layer 3. Is formed.

  The partition walls 5 are provided to partition the pixels formed by the individual light emitting layers 3 (second electrodes 4). In the case of a color organic EL display, the pixels are formed of red, green and blue pixels periodically. The light emitting layer 3 has a structure in which an electron injection layer, an electron transport layer, a light emitting portion, a hole injection layer, a hole transport layer (not shown), and the like are laminated. When a voltage is applied by 4 and electrons and holes are recombined, light is emitted from the light emitting portion. In the first embodiment, a TFT wiring (not shown) is formed on the second electrode 4 side, and light is emitted to the first electrode 2 and the substrate 1 side, so-called top emission type organic EL. Suppose that it is a display device.

  A concave portion 6 is formed in a portion of the substrate 1 where the light emitting layer 3 and the second electrode 4 are laminated and where light emitted from the light emitting layer 3 is transmitted. The recess 6 is formed in a spherical shape such as a spherical lens, and the first electrode 2 is formed on the surface of the substrate 1 on the side where the recess 6 is formed. The first electrode 2 is filled in the entire interior of the recess 6 and is formed flat so that the surface in contact with the light emitting layer 3 on the side opposite to the recess 6 is a flat surface. In the organic EL display device shown in FIG. 1, a flat light emitting layer 3 and a second electrode 4 are formed in a portion corresponding to the recess 6 of the first electrode 2. In addition, the recessed part 6 of this Embodiment 1 is circular when it sees from the upper surface side of an organic electroluminescence display, and shall be formed in the part of each light emitting layer 3 (2nd electrode 4) separately. However, the shape seen from the upper surface side of the recess 6 is not limited to a circle, and may be other shapes.

  In the organic EL display device shown in FIG. 1, the concave portion 6 is formed in a spherical shape on the surface of the substrate 1, and the first electrode 2 is filled in the entire inside of the concave portion 6 to have a convex lens shape. The partial first electrode 2 functions as a lens. Therefore, it is possible to suppress reflection due to total reflection or the like when light (see an arrow in FIG. 1) that is emitted in an oblique direction through the interface between the first electrode 2 and the substrate 1 is transmitted. Moreover, since the condensing effect is also acquired, the luminous efficiency of the organic EL display device can be improved.

FIG. 2 is a schematic vertical sectional view showing another example of the organic EL display device according to Embodiment 1 of the present invention. The organic EL display device of FIG. 2 differs from the organic EL display device of FIG. 1 only in the shapes of the first electrode 2, the light emitting layer 3, and the second electrode 4, and the other portions are the organic EL display device of FIG. It is assumed that Also, the same components as those of the organic EL display device of FIG.
In the organic EL display device shown in FIG. 2, the first electrode 2 is formed thin so as to coat the inner surface of the recess 6 without filling the entire interior of the recess 6. A light emitting layer 3 is formed on the first electrode 2 so as to coat the recess. For this reason, both the surface in contact with the first electrode 2 and the surface in contact with the second electrode 4 of the light emitting layer 3 are spherical. The second electrode 4 is laminated on the light emitting layer 3 so that the surface opposite to the light emitting layer 3 is flat. Note that the surface of the second electrode 4 opposite to the light emitting layer 3 is not necessarily flat.

  In the organic EL display device of FIG. 2, since the thickness of the first electrode inside the recess 6 is thin, the effect as a lens is lower than that of FIG. 1, but the surface of the light emitting layer 3 in contact with the first electrode 2 Since both surfaces in contact with the second electrode 4 are spherical, the light emitted from the light emitting layer 3 is incident at an angle close to a right angle with respect to the surface of the first electrode 2 and the substrate 1, and the light caused by total reflection or the like Reflection can be suppressed.

FIG. 3 is a schematic longitudinal sectional view showing another example of the organic EL display device according to Embodiment 1 of the present invention. The organic EL display device of FIG. 3 differs from the organic EL display device of FIG. 1 only in the shapes of the first electrode 2, the light emitting layer 3, and the second electrode 4, and the other portions are the organic EL display device of FIG. It is assumed that Also, the same components as those of the organic EL display device of FIG.
In the organic EL display device shown in FIG. 3, the first electrode 2 is thinly formed so as to coat the inner surface of the recess 6 without filling the entire interior of the recess 6. The light emitting layer 3 is formed in the recess of the first electrode 2 so as to fill the recess. For this reason, the surface in contact with the first electrode 2 of the light emitting layer 3 is spherical. Further, the surface of the light emitting layer 3 in contact with the second electrode 4 is formed flat, and this surface and the surface opposite to the light emitting side of the first electrode 2 (excluding the concave portion 6) are the same plane. It is supposed to become.

  In the organic EL display device of FIG. 3, the light emitted from the light emitting layer 3 is incident at an angle close to a right angle with respect to the surface of the first electrode 2 and the substrate 1, as in the organic EL display device of FIG. 2. Light reflection due to total reflection or the like can be suppressed.

FIG. 4 is a schematic longitudinal sectional view showing another example of the organic EL display device according to Embodiment 1 of the present invention. The organic EL display device of FIG. 4 differs from the organic EL display device of FIG. 1 only in the shapes of the first electrode 2, the light emitting layer 3, and the second electrode 4, and the other portions are the organic EL display device of FIG. It is assumed that Also, the same components as those of the organic EL display device of FIG.
In the organic EL display device shown in FIG. 4, the first electrode 2 is formed thin so as to coat the inner surface of the recess 6 without filling the entire interior of the recess 6. Then, the light emitting layer 3 and the second electrode 4 are filled with the light emitting layer 3 and the second electrode 4 so that the opening 7 of the hollow formed in the first electrode 2 becomes flat. Further, the surface of the second electrode 4 that is not in contact with the light emitting layer 3 and the surface of the light emitting layer 3 that is not in contact with the first electrode 2 and the second electrode 4 are formed flat. These surfaces and the first electrode The surface opposite to the side from which the light 2 is emitted (excluding the concave portion 6) is formed in the same plane.

  In the organic EL display device of FIG. 4, light emitted from the light emitting layer 3 is incident at an angle close to a right angle with respect to the surfaces of the first electrode 2 and the substrate 1, as in the organic EL display device of FIG. 2. Light reflection such as total reflection can be suppressed. Further, since the light emitting layer 3 and the second electrode 4 are filled in the depression formed in the first electrode 2 so that the opening 7 of the depression is flat, the first electrode 2, the light emitting layer 3 and the first electrode 2 are filled. The two electrodes 4 can be formed thin, and the entire organic EL display device can be thinned by reducing the thickness of the partition walls 5.

  In the first embodiment, a curved concave portion 6 is formed in a portion of the surface of the substrate 1 where light emitted from the light emitting layer 3 is transmitted, and the first electrode 2 is formed in the concave portion 6 to function as a lens. Therefore, reflection of light emitted in an oblique direction at the interface between the first electrode 2 and the substrate 1 can be suppressed, a light collecting effect can be obtained, and an organic EL display device with high luminous efficiency. Can be obtained.

Embodiment 2. FIG.
FIG. 5 is a schematic longitudinal sectional view showing a manufacturing process of an organic EL display device according to Embodiment 2 of the present invention. In the second embodiment, a process of manufacturing the substrate 1 of the organic EL display device shown in FIGS. 1 to 4 of the first embodiment is shown.
First, a glass substrate 1a is prepared (FIG. 5A), and a resist 10 is patterned on one surface by photolithography (FIG. 5B). This patterning is performed so that an opening is formed at the center of the portion to be the recess 6. Then, using the resist 10 as a mask, wet etching is performed with a hydrofluoric acid chemical solution to form the recess 6 (FIG. 5C). In FIG. 5C, dry etching with gas may be performed instead of wet etching with hydrofluoric acid chemical solution. Finally, the resist 10 is removed to complete the substrate 1 (FIG. 5D).

  Here, the manufacturing method in which the concave portion 6 is formed by wet etching with a hydrofluoric acid chemical solution or dry etching with gas is shown, but the concave portion 6 may be formed by sandblasting instead. Sand blasting is to form the recess 6 by spraying fine particles and hitting the glass substrate 1a, and it is not necessary to form the resist 10 in FIG. 5B. In addition, in order to form the spherical recessed part 6, there exists a method of rotating and moving the jet nozzle which ejects a micro particle | grain. There is also a method of forming the recess 6 directly in the glass substrate 1a by mechanical cutting means.

  The manufacturing method of the organic EL display device after the substrate 1 in which the recess 6 is formed is the same as the manufacturing method of the conventional organic EL display device. That is, the partition wall 5 is formed after the first electrode 2 made of ITO or the like is formed by sputtering or the like. Then, the light emitting layer 3 made of an electron injection layer or the like is formed by vapor deposition or the like, and the second electrode 4 is formed by sputtering or the like. Thereafter, TFT wiring, a sealing film, and the like are formed to complete the organic EL display device.

In the second embodiment, since the spherical concave portion 6 is formed in the portion of the surface of the glass substrate 1a where the light emitted from the light emitting layer 3 is transmitted, as described in the first embodiment, the first electrode 2 and the substrate The reflection of light emitted in an oblique direction at the interface of 1 can be suppressed and a light collecting effect can be obtained, so that the light emission efficiency of the organic EL display device can be improved.
Moreover, the recessed part 6 can be easily formed by processing the glass substrate 1a by the wet etching by a hydrofluoric acid type chemical | medical solution, or the dry etching by gas.

  The structure of the organic EL display device according to the present invention can be applied in the form of forming a recess in the light emitting surface of a self-luminous display device (for example, an inorganic EL) other than the organic EL display device.

1 is a schematic longitudinal sectional view showing a main part of an organic EL display device according to Embodiment 1 of the present invention. FIG. 6 is a schematic vertical sectional view showing another example of the organic EL display device according to the first embodiment. FIG. 6 is a schematic vertical sectional view showing another example of the organic EL display device according to the first embodiment. FIG. 6 is a schematic vertical sectional view showing another example of the organic EL display device according to the first embodiment. FIG. 6 is a schematic longitudinal sectional view showing a manufacturing process of an organic EL display device according to Embodiment 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate, 2 1st electrode, 3 Light emitting layer, 4 2nd electrode, 5 Partition, 6 Recessed part, 7 Opening part, 10 Resist.

Claims (12)

A substrate, a transparent first electrode formed on the surface of the substrate, a light emitting layer laminated on the first electrode, and a second electrode laminated on the light emitting layer,
An organic EL display device, wherein a concave portion is formed in a portion of the surface of the substrate through which light emitted from the light emitting layer is transmitted.   2. The organic EL display device according to claim 1, wherein the concave portion is formed in a spherical shape, and the first electrode functions as a lens.   The organic EL display device according to claim 1, wherein the substrate is made of glass.   The organic material according to any one of claims 1 to 3, wherein the first electrode is filled in the entire interior of the recess, and a surface of the first electrode that contacts the light emitting layer is formed flat. EL display device.   4. The organic EL display device according to claim 1, wherein a surface of the light emitting layer in contact with the first electrode and a surface in contact with the second electrode are both spherical.   The surface of the light emitting layer in contact with the first electrode is formed in a spherical shape, and the surface of the light emitting layer in contact with the second electrode is formed flat. The organic EL display device described.   6. The organic EL display device according to claim 5, wherein the depression formed in the first electrode is filled with the light emitting layer and the second electrode so that the opening of the depression is flat. Manufacture of an organic EL display device comprising a substrate, a transparent first electrode formed on the surface of the substrate, a light emitting layer laminated on the first electrode, and a second electrode laminated on the light emitting layer A method,
A step of forming a spherical recess in a portion of the surface of the substrate through which light emitted from the light emitting layer is transmitted; and the first electrode is provided on the surface of the substrate at least in the recess. An organic EL display comprising: a step of forming a part of the light-emitting layer so as to function as a lens; a step of stacking a light-emitting layer on the first electrode; and a step of stacking a second electrode on the light-emitting layer. Device manufacturing method.   9. The method of manufacturing an organic EL display device according to claim 8, wherein the step of forming the concave portion is performed by wet etching.   9. The method of manufacturing an organic EL display device according to claim 8, wherein the step of forming the recess is performed by dry etching.   9. The method of manufacturing an organic EL display device according to claim 8, wherein the step of forming the concave portion is performed by sand blasting. 9. The method of manufacturing an organic EL display device according to claim 8, wherein the step of forming the recess is performed by mechanical cutting means.

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