JP4522459B2 - Organic EL panel - Google Patents

Description

  In the present invention, organic EL elements arranged in a matrix and a plurality of thin film transistors for driving the organic EL elements are provided on a substrate, and a pixel area above the pixel area where the organic EL elements are arranged in a peripheral portion of the substrate. It is related with the organic electroluminescent panel which joins the sealing panel which seals.

  Conventionally, an organic EL display panel (organic EL panel) is known as one of flat display panels. Unlike a liquid crystal display panel (LCD), this organic EL panel is expected to be widely used as a flat display panel that emits light and is bright and easy to see.

  This organic EL panel is configured by arranging a number of organic EL elements as pixels and arranging them in a matrix. In addition, as a driving method of the organic EL element, there are a passive method and an active method as in the LCD, but an active matrix method is preferable as in the LCD. That is, in the active matrix system in which a switch element (usually two for switching and driving) is provided for each pixel and the display of each pixel is controlled by controlling the switch element, the switch element is provided for each pixel. It is preferable because a high-definition screen can be realized as compared with a passive method without a screen.

  Here, the organic EL element causes the organic EL element to emit light by passing a current through the organic light emitting layer. In many cases, a hole transport layer made of an organic material or an electron transport layer is provided in order to assist light emission adjacent to the organic light emitting layer. However, these organic layers are easily deteriorated by moisture.

  Therefore, in an organic EL display, the upper area of the display area where the organic EL element is arranged is covered with a metal cathode, and the upper space of the display area where the organic EL element is arranged (area where the pixel exists) is airtight. As a space, a desiccant is disposed in this space to remove moisture.

JP 2002-203682 A

  However, in such a conventional organic EL display panel, the lifetime is often not sufficient. As a result of the examination, it was found that drying in the upper space of the organic EL element is often insufficient. That is, it has been found that the intrusion of moisture from the outside cannot be prevented sufficiently effectively.

  This invention is made | formed in view of the said subject, and it aims at providing the organic EL panel which can prevent the penetration | invasion of the water | moisture content with respect to the upper space of an organic EL element effectively.

In the present invention, organic EL elements arranged in a matrix and a plurality of thin film transistors for driving these organic EL elements are provided on a substrate, and a peripheral portion of the substrate is disposed above a display region where the organic EL elements are disposed. an organic EL panel for joining the sealing panel covering, said organic EL device covers a plurality of thin film transistors in the planarization film, and forming on the planarizing film, the moisture blocking the planarization film The substrate is provided by adhering a moisture blocking layer covering the planarizing film to a sealing panel with a sealing material around the panel where the planarizing film is present under the moisture blocking layer. And a sealing panel.

As described above, the moisture blocking layer and the sealing material on the planarizing film are connected in the region where the planarizing layer is present below, thereby performing the peripheral sealing, so that the planarizing film in the sealed region is formed into an organic EL element. separated and, thereby it is possible to effectively prevent entry of moisture from the surrounding.

  In addition, another moisture blocking layer is provided below the planarization film and above the thin film transistor, and two moisture blocking layers are connected to the periphery of the substrate, thereby connecting the planarization film side. The part is preferably closed by two moisture blocking layers.

  Thus, by covering the side portion of the planarization film with the moisture blocking layer, it is possible to prevent moisture from entering the panel through the planarization film. Moreover, even if the planarizing film is a highly hygroscopic material, the moisture is blocked by the moisture blocking phase, so that moisture can be prevented from entering the planarizing film. Even if the planarizing film absorbs moisture during the manufacturing process, the moisture does not enter the organic layer because it is wrapped in the moisture blocking layer.

  The moisture blocking layer is preferably made of silicon nitride. Silicon nitride is suitable as a moisture blocking layer because it has high moisture resistance and is stable.

As described above, according to the present invention, the periphery is sealed by connecting the moisture blocking layer and the sealing material in the region where the planarizing film is present below . Thus, in the region existing in the planarizing film no step, as possible out be performed reliably seal around to connect the water blocking layer and the sealant. Therefore , the planarization film is separated from the organic EL element, and this can effectively prevent moisture from entering from the periphery.

  Further, by covering the side portion of the planarizing film with the moisture blocking layer, it is possible to prevent moisture from entering the panel through the planarizing film.

  Silicon nitride is suitable as a moisture blocking layer because it has high moisture resistance and is stable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a main part of one embodiment. On the glass substrate 10, _two insulating layers 12 are formed on the entire surface in order of SiNx and SiO ₂ (SiO ₂ (upper) / SiNx (lower)) in order to prevent impurities from entering from the glass substrate 10. ing. A large number of thin film transistors are formed in the main part on the insulating film 12. In this figure, a second TFT which is a thin film transistor for controlling a current from the power supply line to the organic EL element is shown. Each pixel is also provided with a first TFT that controls the accumulation of the voltage from the data line in the capacitor. The second TFT is turned on in accordance with the voltage accumulated in the capacitor and is turned on from the power supply line to the organic EL element. To control the current flowing to

A semiconductor layer 14 made of polysilicon and forming an active layer is formed on the insulating film 12, and a gate insulating film 16 made of a two-layer film in which SiO ₂ and SiNx are stacked in this order is formed covering the semiconductor layer 14. . A gate electrode 18 made of Mo or the like is formed above the intermediate portion of the semiconductor layer 14 with a gate insulating film 16 interposed therebetween. The gate electrode 18 is covered with two layers of insulating films laminated in order of SiNx and SiO _2. An interlayer insulating film 20 is formed. Further, on both end sides of the semiconductor layer 14, contact holes are formed in the interlayer insulating film 20 and the gate insulating film 16, for example, an aluminum drain electrode 22 and a source electrode 24 are formed.

  A first moisture blocking layer 26 made of a SiNx or TEOS film is formed on the entire surface so as to cover the interlayer insulating film 20, the drain electrode 22, and the source electrode 24.

  A first planarizing film 28 made of an organic material such as an acrylic resin is formed on the first moisture blocking layer 26, and is made of a SiNx or TEOS film on the first moisture blocking layer 26, as with the first moisture blocking layer 26. A second moisture blocking layer 60 is formed. A transparent electrode 30 such as ITO is formed on the second moisture blocking layer 60 as the anode of the organic EL element for each pixel.

  A part of the transparent electrode 30 reaches the source electrode 24 and is also formed on the inner surface of the contact hole exposing the upper surface of the source electrode provided therein. Thereby, the source electrode 24 and the transparent electrode 30 are directly connected.

  The peripheral portion of the pixel region other than the light emitting region of the transparent electrode 30 is covered with a second planarization film 32 made of the same organic material as the first planarization film 28.

  A hole transport layer 34 is formed on the entire surface of the second planarization film 32 and the transparent electrode 30. Here, since the second planarization film 32 is opened in the light emitting region, the hole transport layer 34 is in direct contact with the transparent electrode 30 that is an anode in the light emitting region. On the hole transport layer 34, a light emitting layer 36 and an electron transport layer 38 which are slightly larger than the light emitting region and divided for each pixel are laminated in this order, and a cathode 40 such as aluminum is formed thereon. Has been.

  Therefore, when the second TFT is turned on, a current is supplied to the transparent electrode 30 of the organic EL element through the source electrode 24, a current flows between the transparent electrode 30 and the cathode 40, and the organic EL element emits light according to the current.

  In this example, the second TFT has a configuration in which two transistors that flow current from two drains to one source are connected in parallel. The first TFT is usually a double gate type in which two transistors are connected in series, and has a laminated structure similar to that of the second TFT, although the planar shape is different and the connection relationship is also different.

  In this embodiment, the insulating film 12, the gate insulating film 16, the interlayer insulating film 20, and the first moisture blocking layer 26 are formed on the entire surface so as to reach the periphery on the glass substrate 10. The chemical film 28 terminates slightly before the periphery of the glass substrate 10, and the second moisture blocking layer 60 covers this side surface. The second planarization film 32, the hole transport layer 34, and the cathode 40 are terminated before reaching the periphery. That is, as shown in the figure, the sealing material 52 for bonding the sealing glass 50 to the glass substrate 10 is bonded to the second moisture blocking layer 60 on the glass substrate 10, and the second moisture blocking layer 60 is 2 Covers the side surface of the planarizing film 32 and terminates on the first moisture blocking layer 26 outside the sealing material 52.

  Here, a UV curable resin such as an epoxy resin is used for the sealing material 52, and this is adhered to the second moisture blocking layer 60. The second moisture blocking layer 60 is made of SiNx or TEOS and does not transmit moisture from outside to the inside. Thereby, it is possible to effectively prevent moisture from the outside from entering the internal space of the sealing glass 50. As the second moisture blocking layer 60, a silicon nitride film (SiNx film) is particularly suitable.

  In the conventional configuration, as shown in FIG. 2, the first and second planarization films 28 and 32 are also formed on the glass substrate 10 below the sealing material 52. These first and second planarization films 28 and 32 are made of an organic material such as an acrylic resin, and these have a higher hygroscopicity than SiNx or the like, and therefore, it is easy to introduce moisture into the panel.

  In the present embodiment, the first planarization film 28 is completely covered with an inorganic film such as SiNx having a high waterproof property, so that the space where the organic EL element exists is basically divided into the second moisture blocking film 60 and the sealing material. 52, which is enclosed by sealing glass 50, effectively prevents moisture from reaching the organic EL element.

In many cases, a driver circuit is disposed around the glass substrate 10 on which the sealing material 52 is disposed, and this driver circuit also includes a large number of thin film transistors (TFTs). The drive thin film transistor is formed on the glass substrate 10 in the same process as the first and second TFTs provided for each pixel. Therefore, there are many cases where a thin film transistor exists below the sealing material 52, and in this case, the electrodes 22 and 24 of the thin film transistor protrude on the interlayer insulating film 20, and the first moisture blocking layer 26 covering the thin film electrode is formed. There is also a step.

  However, in the present embodiment, since the first planarization film 28 exists and the above-described step is planarized, no problem occurs.

It is sectional drawing of the principal part which shows the structure of embodiment. It is sectional drawing which shows the structure of a prior art example.

Explanation of symbols

  10 glass substrate, 12 insulating layer, 14 semiconductor layer, 16 gate insulating film, 18 gate electrode, 20 interlayer insulating film, 22 drain electrode, 24 source electrode, 26 first moisture blocking layer, 28 first planarizing film, 30 transparent Electrode, 32 2nd planarization film, 34 hole transport layer, 36 organic light emitting layer, 38 electron transport layer, 40 cathode, 50 sealing glass, 52 sealing material, 60 2nd moisture blocking layer.

Claims (3)

An organic EL element arranged in a matrix and a plurality of thin film transistors for driving these organic EL elements are provided on a substrate, and a sealing covering the periphery of the substrate over the display area where the organic EL element is arranged An organic EL panel for joining panels,
The organic EL element is formed by covering the plurality of thin film transistors with a planarizing film and forming the planarized film on the planarized film.
The water blocking layer is provided on the flattening film,
The substrate and the sealing panel are bonded by adhering the moisture blocking layer covering the planarizing film to the sealing panel with a sealing material around the panel where the planarizing film is present under the moisture blocking layer. An organic EL panel characterized by being bonded to. The organic EL panel according to claim 1,
By providing another moisture blocking layer below the planarization film and above the thin film transistor, and connecting two moisture blocking layers at the periphery of the substrate, the side of the planarization film is An organic EL panel characterized by being closed by two moisture blocking layers. The organic EL panel according to claim 1 or 2,
The organic EL panel, wherein the moisture blocking layer is made of silicon nitride.

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