JP2009016187A - Organic el panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL panel capable of suppressing the occurrence of luminance unevenness and unnecessary deterioration of luminance even in the case it is made a large area. <P>SOLUTION: The organic EL panel has a transparent positive electrode layer 2 and a negative electrode layer 3 installed on its rear side, and an organic EL layer 4 is interposed between the both layers 2, 3. The peripheral edge portions of the positive electrode layer 2 and the negative electrode layer 3 are sealed by an insulating sealing agent 6 throughout the both layers 2, 3, and a part of the peripheral edge portion of the positive electrode layer 2 is exposed to the outside further than the insulating sealing agent 6, and a greater portion of the face on the opposite side to the adjoining face with the organic EL layer 4 of the negative electrode layer 3 is exposed to the outside, and respective exposed parts of the positive electrode layer 2 and the negative electrode layer 3 are secured as a power supply terminal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic EL panel that performs surface-emitting illumination using an EL (electroluminescence) phenomenon.

  In recent years, organic EL panels have been demanded as surface-emitting light sources that illuminate a large area such as various lighting fixtures and light posters. This organic EL panel generates little heat, and is lightweight and thin. In particular, the organic EL element can be easily selected in color as compared with the inorganic EL element, and has a low driving voltage to save power. It has various advantages such as.

  By the way, this type of organic EL panel has conventionally been provided with a structure as shown in FIGS. 3 and 4 (see, for example, Patent Document 1). In this organic EL panel, on a transparent substrate 1 such as glass, a fluorescent material using an organic compound is provided between an anode layer 2 made of a transparent electrode such as ITO and a cathode layer 3 made of a back electrode such as aluminum. A sealing layer 5 made of a glass-based sealing material is formed so as to cover the organic EL layer 4 and to cover these layers 2, 3, and 4.

  Here, the sealing layer 5 is formed in order to prevent the organic compound constituting the organic EL layer 4 from being deteriorated in characteristics when exposed to moisture or oxygen. In order to cause the organic EL layer 4 to emit light, it is necessary to apply a predetermined voltage between the upper and lower anode layers 2 and the cathode layer 3. Therefore, conventionally, when the anode layer 2, the organic EL layer 4, and the cathode layer 3 are sequentially laminated on the substrate 1, after the sealing layer 5 is formed by disposing the respective positions along the plane. The anode layer 2 and the cathode layer 3 are partly exposed to the outside from the sealing layer 5, and the exposed portion is secured as a power supply terminal portion, and a power supply wiring 8 from the DC power source 7 is provided here. I try to connect.

  However, as shown in FIGS. 3 and 4, when the anode layer 2, the organic EL layer 4, and the cathode layer 3 are sequentially displaced along the plane, the anode layer 2 for connecting the power supply wiring and The distance between each connection point P1, P2 of the cathode layer 3 becomes long. In particular, when the area of the organic EL panel is increased for illumination, the anode layer 2 composed of a transparent electrode such as ITO has a large resistance component. Therefore, when the distance between the connection points P1 and P2 increases, the organic EL layer The voltage applied between the anode layer 2 and the cathode layer 3 sandwiching 4 is different depending on the position of the light emitting surface, and as a result, the EL element panel has uneven brightness, which makes it impossible to perform uniform illumination. .

As a countermeasure, in the prior art, for example, a large number of low-resistance auxiliary electrodes made of aluminum or the like are formed in a lattice shape or a stripe shape between the substrate 1 and the anode layer 2 on the light emission side, and the anode layer 2 is fed. There has also been proposed a configuration in which the occurrence of luminance unevenness is suppressed by preventing a potential difference from occurring as much as possible between a portion close to the power feeding terminal portion and a portion away from the portion (for example, see Patent Document 2).
JP 2004-71246 A Japanese Patent Laid-Open No. 2004-14128

  However, as described in Patent Document 2 above, when a large number of auxiliary electrodes are formed between the substrate 1 and the anode layer 2 in a lattice shape or a stripe shape, the occurrence of uneven brightness can be suppressed. However, since this auxiliary electrode blocks most of the light emitted from the organic EL layer 4, there is a problem that the luminance is lowered when viewed as a whole light source. In particular, when used as an organic EL panel for lighting with a large area, a decrease in the brightness of the entire panel is not preferable.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an organic EL panel capable of suppressing the occurrence of uneven luminance and excessive decrease in luminance even when the area is increased. And

  In order to achieve the above object, an organic EL panel according to the first aspect of the present invention has an organic EL layer interposed between a transparent anode layer and a cathode layer provided on the back surface thereof. The peripheral edge portions of the anode layer and the cathode layer are sealed with an insulating sealant over both layers, and a part of the peripheral edge portion of the anode layer is more external than the insulating sealant. On the other hand, the surface of the cathode layer opposite to the surface facing the organic EL layer is exposed to the outside, and the exposed portions of the anode layer and the cathode layer are secured as power supply terminals. It is characterized by being.

  According to the first aspect of the present invention, since the peripheral side edge portions of the anode layer and the cathode layer are sealed with the insulating sealant over both layers, it is possible to reliably prevent deterioration of the characteristics of the organic EL layer. it can. And about an anode layer, the location exposed to the exterior rather than the insulating sealing agent of the peripheral edge part can be used as a feeding terminal, and about a cathode layer, it adjoins and opposes an organic EL layer. An arbitrary portion in the surface opposite to the surface can be used as a power supply terminal. Therefore, the distance between the connection points of the anode layer and the cathode layer can be arbitrarily set, and the distance between the connection points of the anode layer and the cathode layer is not uniquely determined as in the prior art. As a result, the voltage applied to the organic EL layer can be made uniform at the position of the light emitting surface, and even when the light emitting surface is enlarged, the occurrence of uneven brightness can be suppressed. In addition, since it is not necessary to provide an auxiliary electrode as in the prior art, an excessive decrease in luminance can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing the configuration of an organic EL panel according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, corresponding to the prior art shown in FIGS. Corresponding components are denoted by the same reference numerals.

  The organic EL panel of this embodiment includes a transparent substrate 1, and includes an anode layer 2 and a cathode layer 3 positioned on the back side of the anode layer 2 on the substrate 1. 3, an organic EL layer 4 is interposed. In this case, the anode layer 2, the organic EL layer 4, and the cathode layer 3 are all formed in a square shape in this example, but the organic EL layer 4 is longer in each side than the anode layer 2 and the cathode layer 3. Is set to be slightly shorter, and for this reason, the peripheral side portion is inward of the peripheral side portions of the anode layer 2 and the cathode layer 3.

  Here, a transparent glass plate is applied to the substrate 1, but a transparent polyethylene terephthalate (PET) resin or the like can also be applied. The anode layer 2 is made of a transparent electrode such as ITO or ZnO. The cathode layer 3 is made of a metal electrode such as Al or Au. The organic EL layer 4 is obtained by dispersing a high-molecular or low-molecular organic fluorescent material in a resin binder, and a portion of the organic EL layer 4 sandwiched between the anode layer 2 and the cathode layer 3 is a light emitting region. It becomes.

  In this embodiment, the peripheral edge portions of the anode layer 2 and the cathode layer 3 are sealed with an insulating sealant 6 that covers both layers 2 and 3. As the insulating sealant 6 in this case, for example, a low-melting glass preform is applied and melted by laser irradiation to seal the portion sandwiched between the anode layer 2 and the cathode layer 3. The As the insulating sealant 6, it is also possible to use an ultraviolet curable adhesive or a thermosetting adhesive other than the glass preform.

  In addition, a part of the peripheral edge of the anode layer 2 is exposed to the outside without being coated with the insulating sealant 6, and a portion exposed to the outside is secured as a power feeding terminal. On the other hand, the cathode layer 3 is exposed to the outside as it is without being coated with the insulating sealant 6 on the opposite side of the surface adjacent to the organic EL layer 4, and this exposed surface is the feed terminal. As ensured. When the organic EL layer 4 is caused to emit light, the ends of the wiring 8 of the DC power supply 7 are connected to the power supply terminals of the anode layer 2 and the cathode layer 3, respectively.

  Thus, in the organic EL panel of this embodiment, the peripheral edge portions of the anode layer 2 and the cathode layer 3 are sealed with the insulating sealant 6 over both the layers 2 and 3, so that the organic EL layer 4 can be reliably prevented.

  And about the anode layer 2, it can expose to the exterior rather than the insulating sealing agent 6 of the peripheral side edge part, and a part can be made into a feed terminal, and about the cathode layer 3, it is an organic electroluminescent layer An arbitrary portion on the surface opposite to the surface facing adjacent to 4 can be used as a power feeding terminal. Therefore, the distance between the connection points P1 and P2 between the anode layer 2 and the cathode layer 3 can be arbitrarily set, and the distance between the connection points P1 and P2 between the anode layer 2 and the cathode layer 3 is unambiguous as in the prior art. There is no specific decision.

  As a result, the voltage applied to the organic EL layer 4 can be made uniform at the position of the light emitting surface, and even when the light emitting surface is enlarged, the occurrence of uneven brightness can be suppressed. In addition, since it is not necessary to provide an auxiliary electrode as in the prior art, an excessive decrease in luminance can be suppressed.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the organic EL panel of the above embodiment has a quadrangular shape in plan view, but is not limited thereto, and may be a triangular shape or a polygonal shape.

It is a top view of the organic electroluminescent panel in embodiment of this invention. It is sectional drawing which follows the AA line of FIG. It is a top view of the conventional organic electroluminescent panel, and has shown the state which excluded the sealing layer. It is sectional drawing which follows the BB line of FIG. 3, and has shown the state which provided the sealing layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode layer 3 Cathode layer 4 Organic EL layer 6 Insulating sealant

Claims (1)

  In an organic EL panel in which an organic EL layer is interposed between a transparent anode layer and a cathode layer provided on the back surface thereof, the peripheral edge of the anode layer and the cathode layer is an insulating sealing agent over both layers. And a part of the peripheral edge of the anode layer is exposed to the outside of the insulating sealant, while the cathode layer is opposite to the surface facing the organic EL layer. An organic EL panel characterized in that a side surface is exposed to the outside and each exposed portion of the anode layer and the cathode layer is secured as a power supply terminal.

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