JP2010170768A - Organic el device, method for manufacturing organic el device, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL (Electroluminescence) device of high reliability suppressing the occurrence of dark spots. <P>SOLUTION: The organic EL device includes an organic insulating film 14 formed on an element substrate 20; a pixel electrode 15 formed on the organic insulating film 14; an organic light-emitting layer 17 formed on the pixel electrode 15; an inorganic insulating film 16 formed covering the exposed portion of the organic insulating film 14 on the element substrate 20; and a sealing substrate 30 joined to the element substrate 20 through a frame-like joint member 31 formed on the inorganic insulating film 16. An opening H3 of the inorganic insulating film 16 for exposing a part of the organic insulating film 14 is provided inside a region surrounded by the joint member 31, and a desiccant 32 is provided covering the organic insulating film 14 exposed to the opening H3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL device, a method for manufacturing the organic EL device, and an electronic apparatus.

  In general, an organic EL (electroluminescence) element has a defect that it is very weak against oxygen and moisture and deteriorates immediately. An organic EL element generally has a structure connected to a TFT through an interlayer insulating film. However, an organic insulating film suitable as an interlayer insulating film has a characteristic of easily transmitting moisture and absorbing moisture. Yes. Therefore, conventionally, an inorganic insulating film having a moisture permeability smaller than that of the interlayer insulating film is formed between the interlayer insulating film and the organic EL element.

  However, in an organic EL device in which the surface of the interlayer insulating film is completely covered with an inorganic insulating film, film peeling occurs in the interlayer insulating film due to the baking process before the formation of the organic light emitting layer or the heat treatment in the reliability test. There was a problem that the intended effect could not be obtained. This is thought to be because moisture contained in the interlayer insulating film expands the interlayer insulating film due to external factors such as heat and diffuses into the organic light emitting layer.

  Therefore, Patent Documents 1 and 2 propose an organic EL device in which an opening is formed in a part of an inorganic insulating film. According to this configuration, since the release of moisture from the interlayer insulating film is not hindered by the inorganic insulating film, moisture contained in the interlayer insulating film can be efficiently released through the opening. Therefore, generation of dark spots due to moisture in the interlayer insulating film is prevented, and an organic EL device having excellent reliability can be provided.

JP2007-188808 JP2007-250244

  However, the organic EL device in which an opening is formed in a part of the inorganic insulating film has a problem that moisture permeates easily from the outside. Therefore, when the organic EL element is sealed with a sealing substrate and then shipped as a product, the lifetime is not extended as expected compared to the case where the surface of the interlayer insulating film is completely covered with an inorganic insulating film, and not necessarily There was a problem that the expected effect could not be obtained.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a highly reliable organic EL device that suppresses the occurrence of dark spots, a method for manufacturing the organic EL device, and an electronic apparatus. .

In order to solve the above problems, an organic EL device according to the present invention includes an organic insulating film formed on an element substrate, a pixel electrode formed on the organic insulating film, and an organic light emitting formed on the pixel electrode. Layer, an inorganic insulating film formed on the element substrate so as to cover the exposed portion of the organic insulating film, and a frame-shaped bonding member formed on the inorganic insulating film, and bonded to the element substrate An opening of the inorganic insulating film that exposes a portion of the organic insulating film inside a region surrounded by the bonding member, and the opening A desiccant is provided so as to cover the organic insulating film exposed to the part.
According to this configuration, since the opening is formed in a part of the inorganic insulating film, the release of moisture from the organic insulating film is not hindered by the inorganic insulating film. Therefore, moisture contained in the organic insulating film can be easily released through the opening. In addition, since the entry of moisture from the outside is prevented by the desiccant, moisture does not enter through the opening after the product is shipped. Furthermore, since the moisture in the organic insulating film can be absorbed by the desiccant after sealing the light emitting part with the sealing substrate, for example, even when heat treatment is performed in a reliability test before product shipment, In the organic EL device, the organic insulating film is not peeled off and dark spots are not generated. Therefore, it is possible to provide an organic EL device having a long lifetime and excellent reliability.

In the present invention, a light emitting region in which a plurality of pixel electrodes are formed is provided inside a region surrounded by the bonding member, and one or a plurality of the opening portions surround the light emitting region. It is desirable that it be formed.
According to this configuration, since the opening of the inorganic insulating film is disposed outside the light emitting region, for example, the opening is formed as compared with the case where the opening is formed inside the light emitting region (ie, the region between the pixel electrodes). The size and layout of the part can be designed freely. Further, since the desiccant is arranged so as to surround the light emitting region, the amount of the desiccant can be increased, and moisture that enters from the joint portion between the element substrate and the sealing substrate can be effectively captured. Can do. Therefore, for example, when applied to an organic EL device having a top emission structure, the desiccant disposed in the portion overlapping with the light emitting region can be thinned, or by omitting it completely, from the sealing substrate side. The light extraction efficiency can be improved.

In the present invention, the desiccant covers the opening and surrounds the periphery of the light emitting region, and is in close contact with both the sealing substrate and the organic insulating film exposed at the opening of the inorganic insulating film. It is desirable that
According to this configuration, since the desiccant is in close contact with both the element substrate and the sealing substrate, it is possible to more effectively capture moisture entering from the joint portion between the element substrate and the sealing substrate.

The organic EL device manufacturing method of the present invention includes an organic insulating film formed on an element substrate, a pixel electrode formed on the organic insulating film, an organic light emitting layer formed on the pixel electrode, and the element. An inorganic insulating film formed so as to cover a portion of the substrate where the organic insulating film is exposed; a sealing substrate bonded to the element substrate via a frame-shaped bonding member formed on the inorganic insulating film; An opening of the inorganic insulating film that exposes a part of the organic insulating film inside a region surrounded by the bonding member before the formation of the organic light emitting layer. Forming a portion and heating the organic insulating film to release moisture contained in the organic insulating film through the opening, and after forming the organic light emitting layer, the sealing substrate Before or during bonding to the element substrate Characterized in that it comprises a step of placing a desiccant to cover the organic insulating film exposed in the opening of the inorganic insulating film.
According to this method, since the opening is formed in a part of the inorganic insulating film, the release of moisture from the organic insulating film is not hindered by the inorganic insulating film. Therefore, moisture contained in the organic insulating film can be easily released through the opening. In addition, since the entry of moisture from the outside is prevented by the desiccant, moisture does not enter through the opening after the product is shipped. Furthermore, after sealing the light emitting part with the sealing substrate, moisture in the organic insulating film can be absorbed by the desiccant. The organic EL device does not peel off the organic insulating film or cause a dark spot. Therefore, it is possible to provide an organic EL device having a long lifetime and excellent reliability.

In the present invention, the step of forming the inorganic insulating film includes a step of forming an inorganic material film on the organic insulating film so as to cover the pixel electrode, and a part of the inorganic material film is removed to form the pixel electrode. Forming an opening that exposes a portion of the organic insulating film, and forming the opening that exposes a portion of the organic insulating film includes: forming an opening that exposes a portion of the pixel electrode; It is desirable to be performed simultaneously.
According to this method, the opening can be efficiently formed without increasing the number of manufacturing steps.

In the present invention, in the step of bonding the sealing substrate and the element substrate, the sealing substrate to which the desiccant is attached is disposed on the element substrate, and the desiccant is disposed in the opening of the inorganic insulating film. It is desirable to include a step of closely contacting the organic insulating film exposed to the surface.
According to this method, the desiccant can be adhered to both the element substrate and the sealing substrate. Therefore, it is possible to effectively capture moisture entering from the joint portion between the element substrate and the sealing substrate.

An electronic apparatus according to the present invention includes the above-described organic EL device according to the present invention.
According to this configuration, it is possible to provide a highly reliable electronic device that suppresses the occurrence of dark spots.

It is a top view of a line head which is an example of an organic EL device. It is AA 'sectional drawing of FIG. It is explanatory drawing of the manufacturing method of a line head. It is explanatory drawing of the manufacturing method of a line head. It is explanatory drawing of the manufacturing method of a line head. It is explanatory drawing of the manufacturing method of a line head. 1 is a schematic diagram of an image forming apparatus as an example of an electronic apparatus.

[Organic EL device]
FIG. 1 is a plan view of a line head 1 which is an example of the organic EL device of the present invention. The line head 1 has a light emitting region 1A formed by arranging a plurality of organic EL (electroluminescence) elements 19 on a long and thin rectangular element substrate 20. In FIG. 1, the organic EL elements 19 are arranged in two rows in a staggered manner, but they may be formed by one row of organic EL elements 19.

  FIG. 2 is a cross-sectional view of the line head 1. The line head 1 includes an element substrate 20 on which an organic EL element 19 is formed, and a sealing substrate 30 that seals a surface of the element substrate 20 on which the organic EL element 19 is formed. The element substrate 20 and the sealing substrate 30 are bonded and integrated through a frame-shaped bonding member 31 provided at the peripheral edge of the opposing region of both substrates.

The element substrate 20 includes a circuit unit 11 including a TFT (switching element) 12 having a semiconductor layer 123 and a gate electrode 124 on a substrate 10 made of glass or the like. On the surface of the circuit portion 11, an inorganic insulating film 13 mainly composed of SiO ₂ is formed so as to cover the source electrode 121 and the drain electrode 122 of the TFT 12. On the inorganic insulating film 13, an organic insulating film (planarizing film) 14 mainly composed of an acrylic or polyimide resin material having photosensitivity, insulation and heat resistance is formed.

  A pixel electrode (first electrode) 15 made of ITO or the like is formed on the organic insulating film 14. The pixel electrode 15 is connected to the drain electrode 122 of the TFT 12 through a contact hole H 1 that penetrates the organic insulating film 14 and the inorganic insulating film 13.

An inorganic insulating film 16 such as SiO ₂ or SiN is formed on the organic insulating film 14 so as to cover the pixel electrode 15. The inorganic insulating film 16 is formed of a material having a moisture permeability lower than that of the organic insulating film 14, and prevents moisture contained in the organic insulating film 14 from diffusing into the organic EL element 19. The inorganic insulating film 16 is formed so as to cover the entire portion of the element substrate 20 where the organic insulating film 14 is exposed, and prevents moisture from entering the organic insulating film 14 from the outside.

  In the inorganic insulating film 16, an opening H <b> 2 that exposes a part of the pixel electrode 15 is formed. On the inorganic insulating film 16, an organic light emitting layer 17 made of an organic low molecular material or an organic polymer material is formed so as to cover the pixel electrode 15 exposed in the opening H2. A common electrode (second electrode) 18 made of MgAg is formed so as to cover the organic light emitting layer 17. An organic EL element 19 is formed by the pixel electrode 15, the organic light emitting layer 17, and the common electrode 18, and a plurality of organic EL elements 19 are formed along the longitudinal direction of the element substrate 20. 1A is formed (see FIG. 1).

  In FIG. 2, the organic EL element 19 is formed by sandwiching the organic light emitting layer 17 between the pixel electrode 15 and the common electrode 18, but is necessary between the pixel electrode 15 and the organic light emitting layer 17. Depending on the case, a hole injection layer, a hole transport layer, and the like can be formed. In addition, an electron transport layer or an electron injection layer can be formed between the organic light emitting layer 17 and the common electrode 18 as necessary. In the present invention, layers including a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and the like formed by being added to the organic light emitting layer are defined as “organic light emitting layer”.

  In the inorganic insulating film 16, an opening H <b> 3 is formed in a region that does not overlap with the pixel electrode 15. As shown in FIG. 1, the position of the opening H3 is between the joining member 31 and the light emitting region 1A. A large number of openings H3 are formed along the longitudinal direction of the element substrate 20 so as to surround the periphery of the light emitting region 1A. In the present embodiment, the plurality of openings H3 are arranged one by one above and below the light emitting region 1A, but may be arranged by a plurality of rows. Further, it may be formed not only in the longitudinal direction of the element substrate 20 but also in the lateral direction, and arranged so as to surround the light emitting region 1A in a frame shape. Further, a plurality of openings H3 arranged in the longitudinal direction of the element substrate 20 may be connected to form a continuous elongated opening H3.

  A desiccant 32 is disposed in the opening H3 of the inorganic insulating film 16. The desiccant 32 covers the organic insulating film 14 exposed in the opening H <b> 3, and the upper part thereof is in contact with the sealing substrate 30. The desiccant 32 is disposed so as to surround the periphery of the light emitting region 1 </ b> A together with the opening H <b> 3, and is accommodated in a sealed space surrounded by the element substrate 20, the sealing substrate 30, and the bonding member 31. The desiccant 32 may be formed for each opening H3, or a common long and thin line desiccant may be formed for a plurality of openings H3 arranged in one direction.

The desiccant 32 is not particularly limited as long as it exhibits a hygroscopic effect under an atmosphere in the sealed space, and various kinds of desiccants can be used. For example, sodium oxide _{(Na 2 O), (O} K 2) potassium oxide, calcium oxide (CaO), barium oxide (BaO), magnesium oxide (MgO), strontium oxide (SrO), lithium sulfate _(Li 2 _SO 4) , Sodium sulfate (Na ₂ SO ₄ ), calcium sulfate (CaSO ₄ ), magnesium sulfate (MgSO ₄ ), cobalt sulfate (CoSO ₄ ), gallium sulfate (Ga ₂ (SO ₄ ) ₃ ), titanium sulfate (Ti (SO _{4) 2} ), nickel sulfate (NiSO ₄ ), calcium chloride (CaCl ₂ ), magnesium chloride (MgCl ₂ ), strontium chloride (SrCl ₂ ), yttrium chloride (YCl ₃ ), copper chloride (CuCl ₂ ), cesium fluoride ( CsF), tantalum fluoride (TaF ₅ ), niobium fluoride (NbF) ₅ ), calcium bromide (CaBr ₂ ), cerium bromide (CeBr ₃ ), selenium bromide (SeBr ₄ ), vanadium bromide (VBr ₂ ), magnesium bromide (MgBr ₂ ), barium iodide (BaI ₂ ) , Magnesium iodide (MgI ₂ ), barium perchlorate (Ba (ClO ₄ ) ₂ ), magnesium perchlorate (Mg (ClO ₄ ) ₂ ), and the like.

  You may form the desiccant 32 in the surface facing the light emission area | region 1A of the sealing substrate 30 as needed. In this case, since the desiccant 32 having a sufficient thickness is formed around the light emitting region 1A, the thickness of the desiccant disposed on the surface facing the light emitting region 1A can be minimized. In particular, in the line head 1 of the present embodiment, the desiccant 32 is formed so as to be in close contact with both the element substrate 20 and the sealing substrate 30 and to isolate the bonding member 31 from the light emitting region 1A. Intrusion of moisture from the joining region is effectively suppressed. Therefore, the desiccant disposed on the surface facing the light emitting region 1A can be completely omitted. In this case, when applied to a top emission type organic EL device, the light extraction efficiency from the sealing substrate 30 side Can be maximized.

  On the inorganic insulating film 16, a frame-shaped bonding member 31 that surrounds the light emitting region 1 </ b> A and the desiccant 32 is formed. The bonding member 31 is made of epoxy resin, glass frit, or the like, and the element substrate 20 and the sealing substrate 30 are bonded via the bonding member 31.

  3 to 6 are process diagrams showing an example of a method for manufacturing the line head 1. First, as shown in FIG. 3, the circuit portion 11, the inorganic insulating film 13, the organic insulating film 14, and the pixel electrode 15 are formed on the substrate 10 using a known method. Then, an inorganic material film 16A is formed on the organic insulating film 14 so as to cover the pixel electrode 15, and a photoresist M is formed on the inorganic material film 16A. Openings H4 and H5 are formed in the photoresist M on the pixel electrode 15 and on the non-formation region of the pixel electrode 15 (position between the light emitting region and the bonding member).

  Next, as shown in FIG. 4, the inorganic material film 16 </ b> A is wet-etched using the photoresist M as a mask, and the inorganic insulating film 16 having openings H <b> 2 and H <b> 3 on the pixel electrode 15 and the non-formation region of the pixel electrode 15. Form. Subsequently, the organic insulating film 14 is heated to release moisture contained in the organic insulating film 14. For example, the organic insulating film 14 is heated to about 150 to 250 ° C. in a dry air atmosphere and held for about 5 to 120 minutes. As a result, moisture contained in the organic insulating film 14 is released to the outside through the opening H3 of the inorganic insulating film 16.

  Next, as shown in FIG. 5, the organic light emitting layer 17 and the common electrode 18 are formed on the pixel electrode 15 exposed to the opening H <b> 2 using a known method, and the organic EL element 19 is formed.

  Next, as shown in FIG. 6, the element substrate 20 on which the organic EL element 19 is formed and the sealing substrate 30 to which the bonding member 31 and the desiccant 32 are attached are arranged to face each other, and the desiccant 32 and the opening H <b> 3. The element substrate 20 and the sealing substrate 30 are bonded to each other by the bonding member 31. At this time, the desiccant 32 is formed thicker than the gap of the finally obtained sealing space (interval between the sealing substrate 30 and the organic insulating film 14 exposed at the opening H3). Thus, when the sealing substrate 30 is pressed onto the element substrate 20, the desiccant 32 is crushed to cover the entire opening H 3 and to be in close contact with the organic insulating film 14 exposed in the opening H 3. .

  As a method for forming the desiccant 32, a known method such as a vacuum deposition method, a spin coating method, or an ink jet method can be used. A sheet-like desiccant may be adhered to the sealing substrate 30. In this case, a desiccant having a sufficient thickness can be formed by providing a groove in the sealing substrate 30 and fixing the desiccant to the groove using an adhesive.

  According to the line head 1 of the present embodiment, since the opening H3 is formed in a part of the inorganic insulating film 16, release of moisture from the organic insulating film 14 is not hindered by the inorganic insulating film 16. Therefore, moisture contained in the organic insulating film 14 can be easily released through the opening H3. In addition, since the entry of moisture from the outside is prevented by the desiccant 32, moisture does not enter through the opening H3 after product shipment. Furthermore, since the moisture in the organic insulating film 14 can be absorbed by the desiccant 32 after sealing the light emitting part with the sealing substrate 30, for example, heat treatment was performed in a reliability test before product shipment. Even in such a case, the film peeling of the organic insulating film 14 on the line head 1 and the occurrence of dark spots due to the film peeling do not occur. Therefore, it is possible to provide the line head 1 having a long life and excellent reliability.

  Further, since the opening H3 of the inorganic insulating film 16 is disposed outside the light emitting region 1A, for example, compared to the case where the opening H3 is formed inside the light emitting region 1A (that is, the region between the pixel electrodes 15). The size and layout of the opening H3 can be freely designed. Further, since the desiccant 32 is disposed so as to surround the light emitting region 1A, the amount of the desiccant 32 can be increased, and moisture entering from the joint portion between the element substrate 20 and the sealing substrate 30 is effective. Can be captured. Therefore, for example, when applied to a line head having a top emission structure, the desiccant disposed in the portion overlapping the light emitting region 1A can be thinned, or can be omitted completely from the sealing substrate 30 side. The light extraction efficiency can be improved.

  Although the line head has been described as an example of the organic EL device, the present invention is not limited to the line head, and can be applied to various organic EL devices such as an organic EL display. The configuration and shape of the organic EL device are not limited to those described above, and various changes can be made based on design requirements and the like without departing from the gist of the present invention.

[Electronics]
FIG. 7 is a schematic diagram of an image forming apparatus 1000 which is an example of an electronic apparatus including the organic EL device of the present invention. The image forming apparatus 1000 includes a line head module 1003 in which the line head 1 is incorporated as an exposure unit. The line head module 1003 includes a line head 1 in which a plurality of organic EL elements are arranged and arranged, a SL array (lens array) 1001 in which lens elements that form images of the light from the line head 1 in an erecting equal magnification are arranged, and a line A head case 1002 that holds the outer periphery of the head 1 and the SL array 1001. The line head 1 and the SL array array 1001 are held in the head case 1002 in an aligned state. As a result, the SL array 1001 concatenates the light from the line head 1 to the photosensitive drum 1004 at an equal magnification. It is supposed to be imaged. Since the image forming apparatus 1000 of the present embodiment includes the above-described line head 1 according to the present invention, the image forming apparatus 1000 is a highly reliable image forming apparatus that suppresses the occurrence of dark spots.

DESCRIPTION OF SYMBOLS 1 ... Line head (organic EL apparatus), 1A ... Light emission area, 14 ... Organic insulating film, 15 ... Pixel electrode, 16 ... Inorganic insulating film, 16A ... Inorganic material film, 17 ... Organic light emitting layer, 18 ... Common electrode, 19 DESCRIPTION OF SYMBOLS ... Organic EL element, 20 ... Element substrate, 30 ... Sealing substrate, 31 ... Joining member, 32 ... Desiccant, 1000 ... Image forming apparatus (electronic device), H1, H2, H3, H4, H5 ... Opening

Claims (7)

An organic insulating film formed on the element substrate; a pixel electrode formed on the organic insulating film; an organic light emitting layer formed on the pixel electrode; and a portion where the organic insulating film is exposed on the element substrate. An organic EL device comprising: an inorganic insulating film formed to cover; and a sealing substrate bonded to the element substrate via a frame-shaped bonding member formed on the inorganic insulating film,
An opening of the inorganic insulating film that exposes a part of the organic insulating film is provided inside a region surrounded by the bonding member, and a desiccant is provided to cover the organic insulating film exposed to the opening. An organic EL device characterized by that.   A light emitting region in which a plurality of the pixel electrodes are formed is provided inside a region surrounded by the bonding member, and one or a plurality of the openings are formed surrounding the light emitting region. The organic EL device according to claim 1.   The desiccant covers the opening and surrounds the periphery of the light emitting region, and is in close contact with both the sealing substrate and the organic insulating film exposed at the opening of the inorganic insulating film. The organic EL device according to claim 2. An organic insulating film formed on the element substrate; a pixel electrode formed on the organic insulating film; an organic light emitting layer formed on the pixel electrode; and a portion where the organic insulating film is exposed on the element substrate. A manufacturing method of an organic EL device comprising: an inorganic insulating film formed to cover; and a sealing substrate bonded to the element substrate via a frame-shaped bonding member formed on the inorganic insulating film. And
Before forming the organic light emitting layer, forming an opening of the inorganic insulating film to expose a part of the organic insulating film inside a region surrounded by the bonding member, and heating the organic insulating film A step of releasing moisture contained in the organic insulating film through the opening,
A step of disposing a desiccant over the organic insulating film exposed in the opening of the inorganic insulating film after the formation of the organic light emitting layer and before or when the sealing substrate is bonded to the element substrate. A method for producing an organic EL device, comprising: The step of forming the inorganic insulating film includes a step of forming an inorganic material film on the organic insulating film so as to cover the pixel electrode, and a part of the inorganic material film is removed to expose a part of the pixel electrode. Forming an opening to be made, and
5. The organic EL device according to claim 4, wherein the step of forming the opening exposing a part of the organic insulating film is performed simultaneously with the step of forming the opening exposing a part of the pixel electrode. Manufacturing method.   The step of bonding the sealing substrate and the element substrate includes arranging the sealing substrate to which the desiccant is attached on the element substrate, and exposing the desiccant to the opening of the inorganic insulating film. The method for manufacturing an organic EL device according to claim 4, further comprising a step of closely contacting the insulating film.   An electronic apparatus comprising the organic EL device according to claim 1.

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