Organic el element, and electronic apparatus

The present invention relates to organic EL devices and electronic devices.

Conventionally, an organic electroluminescence device (hereinafter referred to as organic EL device) has a configuration in which an anode, a hole transport layer, a light emitting layer, and a cathode are laminated on a glass substrate. Here, the solid organic material used for the hole transport layer and the light emitting layer is easily attacked by moisture, oxygen, and the like, and when the organic EL element is driven in the atmosphere, its light emitting characteristics rapidly deteriorate. Therefore, there is an organic EL element in which a sealing chamber is provided by a sealing glass plate surrounding a light emitting layer and one of the electrodes (for example, Patent Document 1).

The organic EL device of Patent Document 1 encloses an inert gas in the sealing chamber and provides a hygroscopic porous layer on the inner surface of the sealing glass plate. As a result, the sealing glass plate effectively prevents the diffusion of moisture from the atmosphere into the inside, and it is possible to eliminate the adverse effect on the device characteristics. Further, the porous layer removes water adsorbed on the surface of the element portion and the surface of the transparent electrode at the time of manufacturing, and keeps the sealed chamber in a moisture-free state to extend the life of the element.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 10-275679</text></patcit>

<p> However, in the organic EL element of Patent Document 1, water and oxygen flow in from the gap between the glass substrate and the sealing glass plate. In addition, a new manufacturing process for forming the porous layer was required. The present invention has been made to solve the above problems, and an object of the present invention is to provide an organic EL element and an electronic device that reduce the intrusion of oxygen and moisture from the outside.</p>

<p> In order to solve the above problems, the present invention includes an element substrate provided with a plurality of display elements and a sealing substrate that is adhered to the element substrate via an adhesive to seal the plurality of display elements. In the organic EL element, irregularities with a surface roughness Ra = 0.1 to 10 μm were formed on the adhesive surface of the sealing substrate.</p><p> According to the present invention, since the unevenness of the surface roughness Ra = 0.1 to 10 μm formed on the adhesive surface is formed on the sealing substrate side, when forming the wiring to be routed to the outside formed on the element substrate, , The shape of the wiring facing the adhesive surface of the sealing substrate via the adhesive can be formed without making a special shape.</p><p> In the present invention, the adhesive surface of the element substrate is flat. As a result, when forming the wiring routed to the outside on the element substrate, the influence on the wiring is small, and the deterioration of the wiring can be reduced.</p><p> The present invention is an organic EL element including an element substrate having a plurality of display elements and a sealing substrate which is adhered to the element substrate via an adhesive to seal the plurality of display elements. Irregularities with a surface roughness Ra = 0.1 to 10 μm were formed on the adhesive surface of the above.</p><p> According to the present invention, the unevenness is formed on the element substrate side, but since the unevenness is a very fine uneven surface having a surface roughness Ra = 0.1 to 10 μm, when forming a wiring routed to the outside on the element substrate. In addition, the influence on the wiring is small, and the deterioration of the wiring can be reduced.</p><p> In the present invention, the adhesive surface of the sealing substrate is flat. As a result, the shape of the adhesive surface of the sealing substrate can be formed without making it a special shape. In the present invention, the unevenness on the adhesive surface is formed in an annular shape so as to surround the display element. As a result, according to the present invention, a good sealing effect can be obtained in any of the circumferential directions surrounding the display element.</p><p> The present invention includes the organic EL device described above. According to the present invention, the plurality of display elements can be satisfactorily sealed and deterioration of wiring can be prevented, so that a high-performance electronic device can be provided.</p>

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. FIG. 1 (a) is a top view of a light emitting element array 10 applied to an electrophotographic printer such as an optical writing head that irradiates a photoconductor with light, and FIG. 1 (b) is a top view of FIG. 1 (a). It is a cross-sectional view of aa line.

As shown in FIG. 1 (a), in the light emitting element array 10, a plurality of organic electroluminescence elements (hereinafter referred to as organic EL elements) 12 as display elements are arranged on a substrate S as an element substrate. .. In the light emitting element array 10 of the present embodiment, a plurality of (10 in this embodiment) organic EL elements 12 arranged at equal pitches in a vertical row are arranged in two rows. Each of the organic EL elements 12 is arranged so as to be displaced by a half pitch in the vertical direction from the organic EL elements 12 in other adjacent rows. That is, each organic EL element 12 is arranged in a houndstooth pattern.

Further, a bank 14 is formed around the plurality of organic EL elements 12 so as to surround the entire plurality of the plurality of organic EL elements 12. As shown in FIG. 1A, the bank 14 in the present embodiment has a substantially quadrangular shape so as to surround the entire plurality of organic EL elements 12.

As shown in FIG. 1 (b), the bank 14 is composed of a liquid-repellent bank 14a formed on the substrate S and a liquid-repellent bank 14b formed on the liquid-repellent bank 14a. .. A part of the lipophilic bank 14a is formed so as to project from the liquid-repellent bank 14b toward the center of the substrate S. The positivity bank 14a is originally a material having positivity, for example, silicon oxide (SiO).₂). Further, even if it does not have positivity, the surface may be liquefied by subjecting a commonly used known liquefaction treatment. On the other hand, the liquid-repellent bank 14b may be originally made of a material having liquid-repellent properties, for example, a fluororesin. In addition, even if it does not have liquid repellency, CF is formed by forming a pattern of organic resins such as acrylic resin and polyimide resin that are usually used.₄The surface may be made liquid-repellent by plasma treatment or the like.

Further, as shown in FIG. 1 (b), the concave region 16 is formed in the center of the substrate S by the bank 14. A pixel electrode 18 is formed at the bottom of the concave region 16. The pixel electrode 18 of this embodiment has a circular shape. Further, the pixel electrodes 18 of the present embodiment are formed in a plurality of pixels (10 in the present embodiment) arranged at equal pitches in a vertical row, and are arranged in two rows in the horizontal direction. Then, each pixel electrode 18 is arranged so as to be displaced by a half pitch in the vertical direction from the pixel electrodes 18 in other adjacent rows. Each pixel electrode 18 is connected to a data signal output drive circuit (not shown) via independent wiring. Then, the drawing data signal output from the data signal output drive circuit is supplied to the pixel electrode 18.

Further, a light emitting layer 20 is formed at the bottom of the concave region 16 so as to cover the entire surface thereof. As a result, the light emitting layer 20 is also laminated on each pixel electrode 18. Further, the cathode 22 is formed over the entire surface of the liquid-repellent bank 14b and the light emitting layer 20. The cathode 22 is connected to the data signal output drive circuit. Then, the organic EL element 12 is composed of the pixel electrode 18, the cathode 22 formed relative to the pixel electrode 18, and the light emitting layer 20 formed between the pixel electrode 18 and the cathode 22. ..

Further, as shown in FIG. 1 (b), as a sealing substrate for forming a sealing space 30 for sealing the organic EL element 12 between the substrate S and the organic EL element 12 provided on the substrate S. It is equipped with a sealing glass 32. The sealing glass 32 blocks the air from entering the sealing space 30 from the external space 33, and is formed of a material having a low water transmittance such as glass, quartz, synthetic resin, or metal. There is.

The sealing glass 32 is formed in a U-shape with a downward cross-sectional view. The sealing glass 32 has an adhesive surface 36 that faces the first region 34 of the substrate S and is bonded to the first region 34. The first region 34 is set outside the portion of the upper surface of the substrate S where the organic EL element 12 is provided.

Then, the first region 34 and the adhesive surface 36 are bonded to each other via the adhesive 38 (see FIG. 2) to seal the organic EL element 12 between the substrate S on the flat plate and the sealing glass 32. A sealing space 30 is formed. The adhesive 38 is provided over the entire area of the first region 34 (adhesive surface 36) set in a square shape. The adhesive 38 is not particularly limited as long as it can maintain stable adhesive strength and has good airtightness. As the adhesive 38 of the present embodiment, a photocurable epoxy resin that is cured by irradiation with ultraviolet light is used.

Further, as shown in FIG. 1 (b), a desiccant 40 is provided in the sealing space 30. The desiccant 40 suppresses deterioration of the organic EL element 12 arranged in the sealing space 30 due to moisture.

FIG. 2 is an enlarged cross-sectional view of a main part showing the vicinity of the first region 34 and the adhesive surface 36. As shown in FIG. 2, the adhesive surface 36 is a very fine uneven surface with a surface roughness Ra = 0.1 to 10 μm. The groove formed by the concave portion 46 and the convex portion 48 has a shallow depth and is minute. The first region 34 is flat with no recesses or protrusions formed.

Next, a method for manufacturing an organic EL device will be described. First, a plurality of pixel electrodes 18 are patterned at substantially the center of the substrate S so as to be arranged in a houndstooth pattern by a known method. Subsequently, silicon oxide (SiO) on the substrate S so as to surround the entire plurality of pixel electrodes 18 around the plurality of pixel electrodes 18.₂) Is patterned to form a positivity bank 14a. After that, on the formed wicked bank 14a, a fluororesin was patterned so that a part of the wicked bank 14a protruded toward the center of the substrate S, for example, so that the height was 1 to 2 micrometers. To form a liquid-repellent bank 14b. As a result, a bank 14 is formed on the substrate S so as to surround the entire plurality of pixel electrodes 18 around the plurality of pixel electrodes 18. As a result, a concave region 16 is formed in the center of the substrate S on which the pixel electrode 18 is formed.

Subsequently, the light emitting layer 20 is formed in the concave region 16 by the droplet ejection method. That is, the liquid composition formed by dissolving or dispersing the light emitting material constituting the light emitting layer 20 in a predetermined solvent such as xylene is discharged from the nozzle of the discharge head. At this time, the liquid composition is sequentially discharged while the discharge head is moved relative to the substrate S along the guide rail provided on the discharge head, so that the liquid composition is discharged a plurality of times into the concave region 16. As a result, the liquid composition is applied to the entire inner surface of the concave region 16.

Next, the substrate S is heated by placing it on a hot plate, for example, to evaporate the solvent in the liquid composition, and the light emitting layer 20 is formed on the entire surface of the concave region 16. After that, the LiF layer, the Ca layer, the Al layer and the like are laminated on the bank 14 and the light emitting layer 20 by a vapor deposition method or the like to form the cathode 22. Subsequently, a sealing glass 32 having light transmission is formed on the entire surface of the cathode 22.

More specifically, the adhesive surface 36 of the sealing glass 32 is formed into a very fine uneven surface with a surface roughness Ra = 0.1 to 10 μm by a shot blasting device (not shown). The shot blasting apparatus processes by ejecting fine abrasive grains accelerated by a carrier gas such as compressed air from a nozzle and colliding with the adhesive surface 36. As a result, the adhesive surface 36 of the sealing glass 32 becomes a very fine uneven surface with a desired surface roughness.

Next, the wiring 50 is formed on the substrate S. When forming the wiring 50, a metal film such as aluminum is formed on the substrate S by a predetermined method such as vapor deposition or sputtering. Next, the metal film is patterned using a predetermined method such as a photolithography method. In this way, the wiring 50 is formed so as to pass over the first region 34.

Then, the desiccant 40 is arranged on the organic EL element 12 on the substrate S. Next, the adhesive 38 is applied onto the first region 34 of the substrate S. After that, the adhesive surface 36 of the sealing glass 32 and the first region 34 of the substrate S are brought close to each other, the substrate S and the sealing glass 32 are pressed with a predetermined force, and the first region 34 and the adhesive surface 36 are adhered to each other. Adhere via agent 38. Then, the adhesive 38 is irradiated with ultraviolet light. As a result, the adhesive 38 is cured, and the sealing glass 32 is firmly adhered to the substrate S.

According to this embodiment, the following effects can be obtained. (1) According to the present embodiment, the adhesive surface 36 of the sealing glass 32 is made into a minute uneven surface having a surface roughness Ra = 0.1 to 10 μm. As a result, when the wiring 50 formed on the substrate S and being routed to the outside is formed, the shape of the wiring 50 facing the adhesive surface 36 of the sealing glass 32 via the adhesive 38 is changed to a special shape. It can be formed without making it.

(2) According to the present embodiment, the adhesive surface 36 of the sealing glass 32 is made into a minute uneven surface having a surface roughness Ra = 0.1 to 10 μm. As a result, when the wiring 50 formed on the substrate S and being routed to the outside is formed, the wiring 50 in contact with the adhesive surface 36 of the sealing glass 32 via the adhesive 38 is not damaged.

(3) According to the present embodiment, since the adhesive surface 36 of the sealing glass 32 is made an uneven surface, the adhesive area becomes large and the sealing glass 32 can be bonded to the substrate S with a large adhesive force. it can.

(4) According to the present embodiment, since the adhesive surface 36 has a very small surface roughness Ra = 0.1 to 10 μm, the concave portion 46 and the convex portion 48 can be easily formed by shot blasting or the like. Moreover, the distance between the external space 33 and the sealing space 30 can be increased, and the intrusion of oxygen and moisture can be prevented.

(5) According to the present embodiment, since the concave portion 46 and the convex portion 48 provided on the sealing glass 32 are minute, the alignment when the sealing glass 32 is installed on the element substrate is easy. -In the above embodiment, the adhesive surface 36 having the concave portion 46 and the convex portion 48 is manufactured by the shot blasting apparatus, but it may be manufactured by the nanoimprint apparatus provided with the mold. More specifically, the mold and the sealing glass 32 are heated above the glass transition temperature of the sealing glass 32. Then, the mold is pressed against the sealing glass 32 and held for a certain period of time. After that, the mold and the sealing glass 32 are cooled to a temperature equal to or lower than the glass transition temperature of the sealing glass 32, and the mold and the sealing glass 32 are separated from each other. As a result, the adhesive surface 36 having the concave portion 46 and the convex portion 48 can be formed as in the above embodiment, and the same effect can be obtained. Further, not limited to the nanoimprint apparatus, an etching method, a laser processing method, an excavation method, or the like may be used.

-In the above embodiment, a minute uneven surface having a surface roughness Ra = 0.1 to 10 μm is formed on the adhesive surface 36 of the sealing glass 32. Even if this is not provided on the adhesive surface 36 of the sealing glass 32, a minute uneven surface as an uneven surface having a surface roughness Ra = 0.1 to 10 μm due to the concave portion and the convex portion is provided in the first region 34 of the substrate S. Good. Even in this case, since the concave portion and the convex portion are minute, the influence on the wiring routing on the substrate S can be reduced, and the deterioration of the wiring 50 can be reduced.

-In the above embodiment, the case where it is mainly applied to an electronic device such as an optical writing head for an electrophotographic printer has been described. For example, a display in which colorization is performed by combining a matrix-shaped white light emitting element with a color filter. It can also be used for electronic devices such as devices.

<figref num="1">(a) is a top view of the light emitting element array of the present embodiment, and (b) is a sectional view taken along line aa in (a).</figref><figref num="2">The partially enlarged view of the light emitting element array of this embodiment.</figref>

Code description

12 ... Organic EL element, 32 ... Sealed glass, 34 ... 1st area, 36 ... Adhesive surface, 38 ... Adhesive, 46 ... Concave, 48 ... Convex , 50 ... wiring.