JP2009048814A - Organic electroluminescent illuminating device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To aim at reduction of pattern-forming defects of an organic EL element part and restraint of degradation of a light volume, in an illuminating device made by arraying a plurality of organic EL elements in parallel. <P>SOLUTION: The organic EL illuminating device is provided with a transparent substrate 1, transparent electrode layers 2 formed on the transparent substrate 1, organic material layers 3 each formed on the transparent electrode 2, and cathode layers 4 each formed on the organic material layer 3. Striped grooves 8 are formed on a face of the transparent substrate 1 at a side where the transparent electrode layers 2 are formed. Each transparent electrode layer 2 is arranged inside the groove 8, and the organic material layer 3 is formed on the transparent substrate 1 as it is laminated on the transparent electrode layer 2 in the groove 8, in a single pattern as seen from a side where each groove 8 is formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lighting device using an organic electroluminescence (hereinafter abbreviated as organic EL) element and a method for manufacturing the same. The organic EL is also called OLED (Organic Light Emitting Diode).

  The organic EL lighting device is generally developed in a shape that forms a single plane that matches the substrate size and obtains planar light emission.

  As shown in FIG. 3, an organic EL lighting device as a background art includes a transparent substrate 1 that serves as a light emission surface, a transparent electrode layer 2 that serves as an anode formed on the substrate 1, and the transparent electrode layer 2. The organic material layer 3 and the cathode layer 4 are sequentially laminated on the substrate. Further, on the transparent substrate 1, a sealing substrate 5 that seals the laminated body including the layers 2, 3, and 4 is bonded. A sealing agent 6 is attached to the inner surface of the sealing substrate 5. In order to feed power from the periphery of the transparent substrate 1 to the organic EL layer, the outer peripheral dimensions of the transparent electrode layer 2, the organic material layer 3, and the cathode layer 4 are respectively set so that the transparent electrode layer 2 and the cathode layer 4 are not in direct contact with each other. Slightly different. Moreover, light emission is obtained from a portion constituting the surface of the organic material layer 3 in a region constituted by the transparent electrode layer 2, the organic material layer 3 and the cathode layer 4.

  In the case of the organic EL lighting device configured as described above, no light is emitted when a defect occurs even at one location in the light emitting surface. In the above configuration, since power is fed from the periphery of the substrate, in-plane resistance from the substrate peripheral side to the center of the substrate is caused, and both the anode and cathode electrodes are transferred from the anode and cathode to the organic layer at the substrate outer periphery and the substrate center. A large difference occurs in the amount of injected current. Therefore, in the organic EL element that can emit light in proportion to the injected current, the light emission is non-uniform between the substrate outer periphery and the substrate center. In addition, due to such non-uniformity of light emission, in-plane non-uniformity of heat generation due to light emission also occurs. It becomes. Such problems increase dramatically as the light emitting area of one organic EL lighting device increases.

For this reason, it is more appropriate to suppress defects and heat generation by using a light emitting device with a certain amount of light in parallel rather than the entire light emission. In addition, there exists what was disclosed by patent document 1 as an illuminating device which comprises a some organic EL element in parallel.
JP 2001-313171 A

  The organic EL lighting device according to the background art of the present invention has been configured to increase the light emitting area by configuring the entire substrate with a single light emitting surface. In this case, if a defect occurs on the EL light emitting surface even at one place, the light emitting surface. The entire surface is turned off.

  On the other hand, when a lighting device is configured by arranging small organic EL elements in parallel instead of using a single light emitting surface, each of the anode layer, the organic material layer, and the cathode layer is subjected to a deposition mask in a vacuum deposition apparatus. Pattern formation was necessary. However, the pattern formation by this vapor deposition mask has a problem that as the size of the substrate increases, there is a problem that a pattern formation defect occurs due to the deflection or warpage of the vapor deposition mask during vapor deposition on a large transparent substrate. In addition, when comparing the light emitting area with the same substrate size, the light emitting area is inevitably reduced as compared with the lighting device constituted by one light emitting surface, and there is a problem that the function (light quantity) as the lighting device is impaired.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve at least one of the problems of the background art as described above. That is, an object of the present invention is to provide a structure and a manufacturing method capable of reducing pattern formation defects in an organic EL element part and suppressing a decrease in light quantity in an illumination device in which a plurality of organic EL elements are arranged in parallel.

  The organic electroluminescence lighting device of the present invention is formed on a transparent substrate, a transparent electrode layer formed on the transparent substrate, an organic layer formed on the transparent electrode, and the organic layer A cathode layer. In this lighting device, a stripe-shaped groove is formed on the surface of the transparent substrate on the side on which the transparent electrode layer is formed, and the transparent electrode layer is disposed inside the groove. Further, the organic layer is formed in a single pattern on the transparent substrate while being partially laminated on the transparent electrode layer in the groove as viewed from the surface side where the groove is formed.

  ADVANTAGE OF THE INVENTION According to this invention, in the illuminating device which arranges a some organic EL element in parallel, reduction of the pattern formation defect of an organic EL element and suppression of a light quantity fall can be aimed at.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the same reference numerals are used for the same components as those of the conventional apparatus of FIG.

  FIG. 1 is a diagram showing a cross section of an organic EL lighting device according to this embodiment.

  In the organic EL lighting device illustrated in this figure, stripe-like grooves 8 are formed and arranged on the upper surface of a transparent substrate 1 such as glass. A transparent electrode layer 2 is formed at the bottom of each groove 8. An organic material layer 3 and a cathode layer 4 are sequentially laminated on the transparent substrate 1. The organic material layer 3 is formed on the upper surface of the transparent substrate 1 while being partially laminated on the transparent electrode layer 2 inside the groove 8. The cathode layer 4 is composed of a film capable of reflecting light.

  The depth of each groove 8 is set to be equal to or greater than the total thickness of the transparent electrode layer 2 and the organic material layer 3. In addition, the cathode layer 4 is laminated with a film thickness that does not cause breakage by the organic material layer 3 laminated on the upper surface portion of the transparent substrate 1 excluding the grooves 8. In this configuration, an organic EL element including the transparent electrode layer 2, the organic material layer 3, and the cathode layer 4 is formed for each stripe-shaped groove 8. As a result, non-lighting of the entire panel due to some element defects can be avoided.

  In this example, the organic material layer 3 was formed in the groove 8 of the transparent substrate 1, so that the side surface of the organic material layer 3 was in contact with the transparent substrate 1 between the grooves 8, and the organic material layer 3 emitted light. Light can be emitted not only from the transparent electrode layer 2 side at the bottom of the groove 8 to the outside but also from the transparent substrate 1 on the side wall of the groove 8. Further, in this embodiment, a phosphor is contained in the transparent substrate 1 in order to suppress a decrease in the amount of light due to a plurality of organic EL elements being distributed on the substrate (that is, to increase the light extraction efficiency). With the above configuration, the amount of light equal to or greater than that of the conventional organic EL lighting device of FIG. 3 is combined with the color conversion and light scattering effect by the phosphor contained in the transparent substrate 1 and the improvement of the light extraction efficiency by the grooves 8. It is possible to provide a lighting device having

  A sealing substrate 5 for sealing a plurality of organic EL elements arranged on the transparent substrate 1 is joined. A sealing agent 6 is attached to the inner surface of the sealing substrate 5. For the sealing agent 6, a getter is used for maintaining a vacuum in a space surrounded by the sealing substrate 5. This sealing structure is the same as the conventional structure of FIG. 3, but the lighting device of the present invention is not limited to the form shown in the reference diagram. Moreover, if the material of the cathode layer 4 does not change the physical properties by the external environment (for example, it is difficult to be oxidized), the sealing structure described above may not be taken.

  FIG. 2 is a plan view showing a film formation layout in the manufacturing stage of the organic EL lighting device of FIG. The transparent electrode layer 2 is disposed at the bottom of the stripe-shaped groove 8 formed in parallel on the transparent substrate 1. Then, the organic material layer 3 and the cathode layer 4 are sequentially formed so as to cover the entire surface excluding the outer peripheral portion of the surface of the transparent substrate 1 where the grooves 8 are formed. The organic material layer 3 and the cathode layer 4 are formed in a substantially single continuous deposited film pattern. These deposited films are formed following the surface shape of the transparent substrate 1 on the side where the grooves 8 are formed. The outer peripheral dimensions of the organic material layer 3 and the cathode layer 4 are slightly changed so that the cathode layer 4 and the transparent electrode layer 2 do not contact each other.

  Thus, the organic material layer 3 and the cathode layer 4 are formed on a substantially entire surface of the transparent substrate 1 in a single pattern as seen in the plan view of FIG. That is, a mask having one large opening on the entire surface can be used. Therefore, it is possible to suppress an element formation defect due to the bending or warping of the mask, as compared with the method of forming a plurality of patterns on the evaporation mask.

  Next, a manufacturing example of the organic EL lighting device will be described with reference to FIGS. FIG. 3 is a process diagram showing the manufacturing method of this embodiment.

  Before the substrate is put into the vacuum deposition apparatus, a resist layer 7 is formed on the transparent substrate 1 such as a glass substrate or a transparent resin plate (FIG. 3A). The transparent substrate 1 may be a substrate containing a phosphor that enables color conversion and light scattering.

  After a stripe-shaped opening pattern is formed on the resist layer on the transparent substrate 1 by photolithography, a stripe-shaped groove 8 is excavated in the transparent substrate 1 by etching (FIG. 3B). The depth of the groove 8 varies depending on the total thickness of the transparent electrode layer 2 and the organic material layer 3 constituting the organic EL element, but is 1 μm or less at the maximum.

  Further, a transparent electrode material is formed to a thickness of about 110 to 300 nm on the surface of the transparent substrate 1 where the grooves 8 are formed, and the transparent electrode layer 2 is formed inside the grooves 8. After the formation of the transparent electrode layer 2, the resist layer is peeled off to remove the transparent electrode material formed in the portion other than the groove 8 (FIG. 3C). As the transparent electrode material, ITO (indium tin oxide) having conductivity can be used. Since it is difficult to make ITO into a uniform film, unevenness occurs, and short-circuit defects are likely to occur. Therefore, it is preferable to insert a buffer layer that smoothes the unevenness between ITO and the organic layer.

  Thereafter, the transparent substrate 1 in which the transparent electrode layer 2 is formed in the groove 8 is washed. Then, this substrate is put into a vacuum deposition apparatus, and a hole injection / transport layer, a light emitting layer, and an electron transport / injection layer are placed on the surface of the transparent substrate 1 on which the transparent electrode layer 2 is formed. The organic material layer 3 is formed by sequentially forming a film. The organic material layer 3 is not limited to a three-layer structure, and may have a two-layer structure in which a hole injection / transport layer and a light-emitting layer are stacked from the anode side. Organic molecules such as PPV can be used for the organic material layer 3.

  The organic material layer 3 only needs to be laminated on the transparent electrode layer 2 in the groove 8 and may be separated by a step between the upper surface of the transparent substrate 1 and the groove 8 formed on this surface (FIG. 3D )reference). Therefore, the metal mask for vapor deposition used when forming the organic material layer 3 does not need to have a plurality of opening patterns, and may have a shape that shields only the peripheral portion of the transparent substrate 1 serving as an electrode extraction portion (power feeding portion). That is, an evaporation mask having one large opening on almost the entire surface may be used.

  Next, a metal thin film such as magnesium silver alloy or calcium is formed on the transparent substrate 1 so as to cover the entire organic material layer 3 to form the cathode layer 4 (FIG. 3E). When the cathode layer 2 is formed, the metal mask is replaced. The cathode layer mask does not need to have a plurality of opening patterns on the mask side like the organic material layer mask, and the size of the opening is slightly different from the organic material layer mask in accordance with the position of the electrode extraction portion. Just change it.

  Finally, the sealing substrate 5 is bonded to the transparent substrate 1 to obtain the organic EL lighting device of this embodiment (see FIG. 1). As a material for the cathode layer 4 in this example, a magnesium silver alloy or calcium was used so that the electron injection efficiency into the organic layer was improved. This magnesium silver alloy and calcium are sensitive to the surrounding environment and may oxidize to form an insulating layer. Therefore, in this example, a structure in which the cathode layer 4 side is vacuum sealed by the sealing substrate 5 is employed. However, if the physical properties of the cathode layer 4 are not changed in the external environment, the sealing substrate 5 is not necessarily provided.

  According to the above manufacturing method, a plurality of organic EL element portions can be formed in parallel on the transparent substrate 1 without intentionally forming a pattern when the organic material layer 3 and the cathode layer 4 are vacuum-deposited. That is, if the stripe-shaped groove 8 is formed in the transparent substrate 1 and the transparent electrode layer 2 is formed at the bottom of the groove 8, the subsequent organic film formation process of the organic material layer 3 and the cathode layer 4 is large over almost the entire surface. A plurality of juxtaposed organic EL element portions can be satisfactorily formed simply by using a vapor deposition mask having an opening. Therefore, compared to the manufacturing method using a vapor deposition mask having a plurality of opening patterns, it is possible to suppress the formation failure of the organic EL element part due to the deflection or warping of the vapor deposition mask, which is advantageous for increasing the illumination size with an increase in the size of the vapor deposition mask. is there.

  The organic EL lighting device as exemplified above can be used as a light source that does not contain mercury and as a surface light source that is a light source different from a linear light source typified by a fluorescent lamp or a point light source typified by an LED.

1 is a cross-sectional view of an organic electroluminescence lighting device according to an embodiment of the present invention. It is a top view which shows an example of the film-forming layout in the manufacture stage of the organic electroluminescent illuminating device of FIG. It is process drawing which shows the manufacturing method of the Example of this invention. It is a structure sectional view of the organic electroluminescence lighting device by background art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Transparent electrode 3 Organic material layer 4 Cathode 5 Sealing substrate 6 Sealant 7 Resist layer 8 Striped groove

Claims (4)

Organic electroluminescence illumination comprising a transparent substrate, a transparent electrode layer formed on the transparent substrate, an organic layer formed on the transparent electrode, and a cathode layer formed on the organic layer In the device
Striped grooves are formed on the surface of the transparent substrate on the side on which the transparent electrode layer is formed,
The transparent electrode layer is disposed inside the groove, and the organic layer is partially laminated on the transparent electrode layer inside the groove and viewed from the surface side on which the groove is formed on the transparent substrate. The organic electroluminescence lighting device is formed in a single pattern.   2. The organic electroluminescence lighting device according to claim 1, wherein the cathode layer is formed on the organic layer in a single pattern as viewed from a surface side on which the groove is formed. 3.   The organic electroluminescence lighting device according to claim 1, wherein the transparent substrate contains a phosphor. On a transparent substrate, a method for producing an organic electroluminescence lighting device in which a plurality of organic electroluminescence element portions composed of a transparent electrode layer, an organic layer, and a cathode layer are arranged in parallel,
Preparing a transparent substrate and forming a stripe-shaped groove on one surface of the transparent substrate;
Forming the transparent electrode layer in the groove from the one surface side of the transparent substrate;
Forming the organic layer on the one surface of the transparent substrate so that a part of the organic substrate is laminated on the transparent electrode layer inside the groove;
Forming the cathode layer to be laminated on the organic layer on the one surface of the transparent substrate;
The manufacturing method of the organic electroluminescent illuminating device which has these.

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