JP2006245010A - Panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel capable of sufficiently preventing a decrease of a luminescent area even in using for a long time. <P>SOLUTION: The panel 10 is equipped with a substrate 12, a sealing board 14 arranged to be faced to the substrate 12, a luminescent element 16 provided on a surface 12a side facing to the sealing board 14 in the substrate 12, and a sealer layer 24 arranged between the substrate 12 and the sealing board 14 to adhere them as well as including the luminescent element 16 inside. The sealer layer 24 is such that an area of a region A1 contacting the substrate 12 is larger than an area of a region A2 contacting the sealing board 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a panel, for example, a panel on which an EL element or the like is mounted.

A light emitting element such as an EL (ElectroLuminescence) element has a feature that it can be easily reduced in size and weight, and is expected to be applied to a display, illumination, and the like. In order for these light-emitting elements to be put into practical use in the above-mentioned applications, one important factor is that they have a long lifetime. Therefore, conventionally, in order to extend the life by eliminating external influences as much as possible, these light emitting elements are in the form of a panel in which the structure constituting the element is sealed between a substrate and a sealing plate. Often used.

  In recent years, for the purpose of further extending the life of the light emitting element, in the panel having the above-described structure, the space between the substrate and the sealing plate is filled with a sealing agent such as a resin. By filling the sealant in this way, the contact of the light emitting element with the outside air is further suppressed, and thereby the deterioration of the light emitting element is less likely to occur. In addition, since the light emitting element is covered with the sealant in this manner, the influence of the external force on the light emitting element is reduced, so that it is possible to suppress the destruction of the light emitting element due to the application of the external force.

As such a panel in which the sealing agent is filled between the substrate and the sealing plate, for example, a sealing agent disposed on the substrate so as to surround the light emitting element, and the inside of the sealing agent, the pixel portion ( There is known a light emitting device including another sealing agent provided so as to cover the light emitting element) (see Patent Document 1).
JP 2004-39542 A

  However, in the panel described in Patent Document 1, when the panel is used for a long period of time, a region where the light emitting element does not emit light (dark spot) is generated, and the light emitting area tends to decrease gradually. For this reason, the said panel needed the further improvement from a viewpoint of lifetime improvement.

  Accordingly, the present invention has been made in view of such circumstances, and an object of the present invention is to provide a panel that can prevent a reduction in light emitting area even when used for a long period of time.

  The panel of the present invention that achieves the above object includes a substrate, a sealing plate disposed to face the substrate, a light emitting element provided on a surface of the substrate facing the sealing plate, and the substrate. And a sealing agent layer that is disposed between and seals the sealing plate and includes the light emitting element therein, and the sealing agent layer is one of the substrate and the sealing plate The area of the region in contact with one side is larger than the area of the region in contact with the other of the substrate and the sealing plate.

  According to the EL panel having the above-described configuration, it is possible to suppress a decrease in light emission area due to long-term use. According to the study by the present inventors, in the panel (light emitting device) of the above prior art, stress tends to concentrate on the contact interface between the sealing agent covering the light emitting element and the sealing agent formed around the sealing agent, It has been found that cracks and peeling are likely to occur at such an interface. Then, external moisture or the like that has entered from such cracks contacts the light emitting element and degrades it, and as a result, the light emitting area is reduced as described above.

  On the other hand, in the panel of the present invention, since the sealing agent layer has the shape as described above, the substrate and the sealing plate are firmly bonded, and the sealing agent layer is formed inside. Even if the stress is maintained, it is considered that the cracks and the like as described above are hardly generated. Thus, in the panel of the present invention, it is considered that the entry of outside air from cracks or the like is suppressed, and the reduction of the light emitting area is reduced even when used for a long time. In addition, it is considered that when the sealing agent layer has the shape as described above, the substrate and the sealing plate are firmly bonded, thereby improving the durability of the panel.

  Further, the sealing agent layer is filled so as to fill all regions between the substrate and the sealing plate, and covers at least a part of at least one edge portion of the substrate and the sealing plate. Preferably it is formed. By having such a shape, the adhesive strength by the sealant layer is further improved, so that it is possible to further extend the life of the panel.

  Furthermore, the sealing agent layer is preferably made of a cured product of an adhesive composition having optical retardation. An adhesive composition having a light retarding curable property is capable of causing a curing reaction continuously even when light irradiation is stopped once it is irradiated with light.

  For example, when a panel is used for a display application, a color filter is often provided on the sealing plate side. When a conventional sealant is cured by light irradiation, light is attenuated by the color filter. There was a tendency that it was difficult to obtain a sufficiently hardened sealant layer.

  On the other hand, as described above, when the sealant layer is composed of a cured product of an adhesive composition having optical retardation, even if light that has passed through a color filter is irradiated during curing, By using curing together, sufficient curing can occur. As a result, the sealing agent layer is in a sufficiently cured state, and as a result, the durability of the panel and, in turn, the long life can be achieved.

  In the present invention, the area of the region in contact with the substrate or the sealing plate refers to the area of the region surrounded by the outer periphery of the region in contact with the substrate or the sealing plate. For example, an ultrasonic flaw detector (Hitachi) Measured by FineSAT).

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the panel which can prevent the reduction | decrease of a light emission area even when it is a case where it is used for a long period of time.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same element through all figures, and the overlapping description is abbreviate | omitted.

(First embodiment)
First, the structure of the panel according to a preferred embodiment of the present invention will be described. Here, an EL panel including an organic EL element as a light emitting element will be described as an example.

FIG. 1 is a diagram schematically showing a cross-sectional structure of an EL panel according to a preferred embodiment of the present invention. FIG. 2 is a diagram showing a planar structure of the EL panel shown in FIG. As shown in the drawing, the EL panel 10 has a structure in which a substrate 12 and a sealing plate 14 are attached via a sealant layer 24. A spacer 22 is disposed between the substrate 12 and the sealing plate 14.
An EL element portion 16 is mounted on a surface 12 a of the substrate 12 that faces the sealing plate 14. Further, a color filter 18 is provided on the surface 14 b side of the sealing plate 14 facing the substrate 12.

  As the substrate 12, those usually used as a substrate for an EL element can be applied, and examples thereof include a glass substrate, a silicon substrate, a film substrate, and an organic substrate typified by a resin substrate.

  The sealing plate 14 holds the sealing agent layer 24 between the sealing plate 14 and the substrate 12. The sealing plate 14 has an area smaller than that of the substrate 12, and is provided so as to face a region near the center of the substrate 12 so as to cover the upper portion of the EL element portion 16. Such a sealing plate 14 is preferably made of a transparent material such as glass in order to extract light emitted from the EL element portion 16 to the outside.

  The color filter 18 adjusts the emission color when transmitting the light emitted from the EL element unit 16 and enables color display of the panel. As such a color filter 18, a filter having an RGB cell which is usually used in a liquid crystal panel or the like can be suitably applied. Note that when the EL panel 10 is used as illumination or the like, the color filter 18 need not be provided.

  The sealant layer 24 fills a region excluding the EL element portion 16, the color filter 18, and the spacer 22 in a space sandwiched between the substrate 12 and the sealing plate 14. The EL element portion 16 is sealed by the sealant layer 24, thereby preventing contact between the EL element portion 16 and the outside air (air or moisture). Thus, deterioration of the EL element unit 16 due to moisture or the like is suppressed.

  The sealing agent layer 24 is formed between the substrate 12 and the sealing plate 14 so as to include the EL element portion 16 and the spacer 22 therein. Further, the region A1 of the sealing agent layer 24 that is in contact with the substrate 12 is wider than the region A2 that is in contact with the sealing plate 14, and the expanded region A1 is seen outside the sealing plate 14. It has become. In other words, the area of the region A1 is larger than the area of the region A2. With this structure, the sealing agent layer 24 is strongly bonded to the substrate 12. The sealing plate 14 bonded through the sealant layer 24 is also strongly bonded to the substrate 12.

  Further, the sealing agent layer 24 has a shape that wraps around the edge portion 14 a of the sealing plate 24. That is, a part (lower part) of the edge portion 14 a is covered with the sealing agent layer 24. With such a structure, the sealing plate 14 is more strongly bonded to the substrate 12, and intrusion of outside air between the substrate 12 and the sealing plate 14 can be further suppressed.

  This sealing agent layer 24 is comprised from the hardened | cured material of the adhesive composition. The adhesive composition has an adhesive property that allows the substrate 12 and the sealing plate 14 to be bonded to each other, and has transparency capable of transmitting light emitted from the EL element portion 16 after being cured. As such a resin material, either a photo-curing resin or a thermosetting resin may be adopted. However, the resin material easily penetrates into the EL element part 16 by heating, and the EL element part 16 deteriorates. In some cases, a photocurable resin is more preferable.

  Especially, as an adhesive composition for forming the sealing agent layer 24, an adhesive composition having light delayed curing is preferable. According to the adhesive composition having this delayed optical curability, even when irradiated with light having a low output, sufficient curing occurs by using thermosetting described later. Even if light is attenuated by the color filter 18, a sufficient curing reaction occurs.

As this light-delay curable adhesive, a light (particularly ultraviolet light) cation curable adhesive composition is preferable, and an ultraviolet light (UV) cation curable epoxy resin is particularly preferable. Examples of such UV cation curable epoxy resins include epoxy resin compositions mainly composed of a liquid epoxy resin and a photocationic polymerization initiator. Specifically, a mixture of a polymerization initiator containing an anion such as SbF ⁶⁻ , AsF ⁶⁻ , PF ⁶⁻ , and BF ⁴⁻ with bisphenol A type epoxy resin and bisphenol F type epoxy resin as the main component can be exemplified. . Examples of the polymerization initiator include those in which any of the above four anions and a counter ion represented by the following chemical formula (1a) or (1b) form a salt. Of these, trisarylsulfonium hexafluoroantimonate is preferable.

  A plurality (four in this case) of spacers 22 are arranged around the EL element part 16 so as to surround the EL element part 16. That is, the spacers 22 are scattered around the EL element portion 16. Then, both the substrate 12 and the sealing plate 14 are brought into contact with and supported by each other, thereby keeping the both at a constant interval. Examples of the spacer 22 include glass particles, silica particles, resin particles, metal particles, and the like. The shape of the spacer 22 is not limited to a particle shape, and may be a columnar shape, a belt shape, an elliptical shape, or the like.

  The spacer 22 is disposed between the substrate 12 and the sealing plate 14 and is included in the sealant layer 24. In other words, the sealing agent layer 24 has a shape that protrudes outward from the spacer 22. Thus, the sealing agent layer 24 is in a state in which the peripheral portion is open to the outside, so that the outer peripheral portion as in the past is further surrounded by another sealing agent, It has a structure in which it is difficult to keep stress inside.

  The spacer 22 preferably has such a rigidity that it does not deform even when applied with some pressure in order to keep the distance between the substrate 12 and the sealing plate 14 constant. However, it is preferable that the spacer 22 has a good affinity with the sealing agent layer 24 in order to reduce a shift or the like generated between the spacer 22 and the sealing agent layer 24. From these viewpoints, the spacer 22 preferably has a structure in which a rigid core material (for example, metal particles) is dispersed in a flexible material (for example, resin).

  As described above, the EL element portion 16 is provided on the substrate 12 and is sealed by the sealing agent layer 14 filled between the substrate 12 and the sealing plate 14. Here, the structure of the EL element unit 16 mounted on the EL panel 10 will be described with reference to FIG. FIG. 3 is a diagram schematically showing a cross-sectional structure of a main part of the EL element portion. Here, an example in which an organic EL element is formed as the EL element portion 16 will be described.

  In the EL element portion 16, an anode 30, a hole injection layer 32, a hole transport layer 34, a light emitting layer 36, an electron transport layer 38, an electron injection layer 40, and a cathode 42 are sequentially formed on the substrate 12. The EL element unit 16 is a so-called top emission type organic EL element that takes out light emitted from the light emitting layer 36 from an end surface opposite to the substrate 12.

  In the EL element section 16, the anode 30 can be a transparent electrode such as ITO (Indium Tin Oxide) or a reflective electrode such as metal, and the latter reflective electrode from the viewpoint of efficiently extracting light. Is preferred. On the other hand, the cathode 42 is preferably a transparent electrode such as ITO in order to extract light from the light emitting layer 36.

  As the hole injection layer 32, the hole transport layer 34, the electron transport layer 38, and the electron injection layer 40, those made of known materials applicable to these uses in the organic EL can be applied. Further, the light emitting layer 36 may be either a low molecular material or a high molecular material. The light emitting layer 36 may be doped with a desired organic material or the like.

  Note that the organic EL panel 10 is not limited to a mode in which light is extracted from the sealing plate 14 side as described above. For example, the substrate 12 may be made of a transparent material and light may be extracted from the substrate 12 side. . Such an EL element unit 16 constitutes a so-called bottom emission type organic EL element. In this case, it is not necessary to provide the color filter 18 on the sealing plate 14 side, and it is preferable to arrange the color filter 18 at an arbitrary position on the substrate side.

  Next, a method for manufacturing the EL panel 10 having the above-described structure will be described.

  In the method of manufacturing the EL panel 10, first, the substrate 12 is prepared, and the layers constituting the EL element unit 16 described above are laminated thereon. The formation method of each layer is arbitrary. For example, when a layer made of an inorganic material or a low molecular organic material is formed, a vapor deposition method is used, and when a layer made of a high molecular organic material is formed, a known method is used. Application methods and printing methods can be applied.

  Next, a plurality of particulate spacers 22 are scattered around the EL element portion 16. At this time, the spacer 22 may be formed by, for example, applying a resin composition containing a core material and a resin around the EL element portion 16 and curing the resin composition. The application of the resin composition can be performed using, for example, a screen printing method or a dispenser.

  Subsequently, a sealing agent constituting the sealing agent layer 24 after curing is dropped inside the spacer 22. As the sealant, a resin material that can constitute the sealant layer 24, preferably an adhesive composition having a light delayed curing property can be used. Here, additives other than resin materials, such as a filler, may be contained in the sealing agent, for example.

  In addition, when the spacer 22 is formed using the resin composition containing a core material and resin, it is preferable that resin in a resin composition has a viscosity higher than a sealing agent. In this case, when the resin composition is applied around the EL element portion 16, the resin is less likely to flow than the sealing agent, and the core material can be firmly fixed to the surface 12a of the substrate 12 with the resin. For this reason, the shift | offset | difference from the position planned about the spacer 22 is fully prevented. As a result, it is possible to make the gap between the sealing plate 14 and the substrate 12 uniform, and it is possible to sufficiently prevent the occurrence of distortion due to stress, the occurrence of microscopic cracks and peeling, and the reduction of the light emitting region more sufficiently. Can be prevented. At this time, the resin is not particularly limited as long as it can fix the core material to the substrate 12 or the sealing plate 14 and has a viscosity higher than that of the sealant. Examples of such a resin include polyamide, Acrylate or the like can be used.

  The amount of the sealant added is such that at least the EL element portion 16 and the spacer 22 are included inside after the sealing plate 14 is bonded together as will be described later. In a preferred case, the space between the substrate 12 and the sealing plate 14 is filled with the sealant layer 24, and the peripheral edge protrudes outside the substrate 12 or the sealing plate 14.

  In the manufacture of the EL panel 10, the structure including the substrate 12, the EL element portion 16, the spacer 22, and the sealant is formed, and the sealing plate 14 provided with the color filter 18 is prepared. As a method of forming the color filter 18 on the sealing plate 14, there is a method of sequentially forming R, G, and B color filters on the sealing plate 14 by a photolithography method or the like.

  Then, the structure described above and the sealing plate 14 provided with the color filter 18 are bonded together to obtain a panel precursor. In such bonding, first, the sealing plate 14 is disposed with respect to the structure so that the EL element portion 16 and the color filter 18 face each other. Subsequently, the substrate 12 and the sealing plate 14 are pressurized from the outside. At this time, heating may be performed together with pressurization.

  As described above, when the spacer 22 is made of a core material and a resin, the resin is crushed by the pressurization, but the interval between the substrate 12 and the sealing plate 14 is preferably determined by a more rigid core material. To be kept. As a result, the spacers 22 are in close contact with the sealing agent, the substrate 12, the sealing plate 14 and the like by the resin, thereby making it difficult for the EL panel 10 to be displaced.

  Thereafter, the sealing agent sandwiched between the substrate 12 and the sealing plate 14 is cured to form the sealing agent layer 24, whereby the substrate 12 and the sealing plate 14 are bonded to each other, and the structure shown in FIG. The EL panel 10 is obtained. Curing of the sealing agent is performed by appropriately selecting means such as photocuring and thermosetting according to the resin material constituting the sealing agent. In the case of using an adhesive composition having light retardation as described above (hereinafter referred to as “light retardation curable composition”) as a sealant, curing is not caused at once by light irradiation. It is preferable to perform two-stage curing as shown below.

  That is, first, light is irradiated to the light delayed curable composition that is a sealing agent, and the polymerization reaction of the composition is started to partially cure. Here, “partially cured” refers to a state where the curable composition is not completely cured and maintains a certain degree of fluidity. The degree of curing of the curable composition can be measured by, for example, a differential thermal scanning calorimeter (DSC). In the first curing step, the sealing agent is preferably cured to such an extent that it maintains a rubbery state.

  The light used for curing is not particularly limited as long as it is a light that can cause curing of the light-delay curable composition. For example, when the composition is cured by irradiation with ultraviolet light. UV light is used. As the ultraviolet light, for example, light emitted from a high-pressure mercury lamp can be used.

  Partial curing of the light-retarding curable composition may be caused by setting the conditions such as the amount of light irradiation and the irradiation time to the sealing agent so that the curable adhesive composition does not completely cure. it can. Specifically, for example, light emitted from a light source usually used for curing a photocurable resin is attenuated through a filter or the like, and then irradiated to a sealing agent, or light from such a light source is conventionally used. The method of irradiating for shorter time is mentioned. Note that when a light source whose light output is adjustable is used, light that has been adjusted to an output suitable for partial curing in advance may be irradiated.

  In particular, when the panel precursor has a transparent sealing plate 14 including the color filter 18 as in the present embodiment, the conventional light source is disposed on the sealing plate 14 side. Since the light emitted from the light source is attenuated by the color filter 18, the sealing agent is irradiated with light suitable for partial curing as described above.

In curing the light delayed curable composition, the sealing agent after light irradiation is then heated. Thereby, the polymerization reaction of the partially cured light delayed curable composition further proceeds, and the composition is almost completely cured. Thus, the sealing agent layer 24 is formed. In the heating step, light irradiation may be continued or stopped.

  In this step, the polymerization reaction generated in the curable adhesive composition by the above-described light irradiation further proceeds by heating. For example, when a UV cation curable epoxy resin is used as the curable adhesive composition, cationic polymerization initiated by light irradiation proceeds in a chain by heating, whereby the UV cation curable epoxy resin becomes Almost completely cured.

  In the EL panel 10 having the above-described configuration, the sealing agent layer 24 has a structure including not only the EL element portion 16 but also the spacer 22 therein. Conventionally, the sealant filled in the panel has been surrounded by other sealants on the outside, and it has been easy for stress to concentrate between the internal and external sealants. The stress generated in the agent was easily retained. For this reason, the conventional panel has cracks and peeling due to the stress, and the light emitting elements tend to be gradually deteriorated by the outside air (humidity and the like) entering from the cracks.

  On the other hand, in this embodiment, since the contact area between the sealing agent layer 24 and the spacer 22 is small, the stress concentration as described above hardly occurs, and cracks, peeling, etc. may occur between them. Significantly less. As a result, the EL element portion 16 sealed in the sealant layer 24 has very little contact with the outside air due to cracks and the like, and a non-light emitting region (dark spot) is hardly formed even after long-term use.

  In particular, as described above, when the sealant layer 24 is made of a cured product of an adhesive composition having optical retardation, the stress of the sealant layer 24 is particularly reduced. Therefore, with this configuration, cracks and the like of the EL panel 10 are further less likely to occur, and the life of the EL panel 10 can be further increased.

(Second Embodiment)
Next, a second embodiment of the panel according to the present invention will be described with reference to FIG.

  FIG. 4 is a diagram schematically showing a cross-sectional structure of an EL panel according to the second embodiment of the present invention. As shown in FIG. 4, the panel 110 of this embodiment is different from the panel 10 of the first embodiment in that the spacers 22 are not provided.

  According to this panel 20, the region A <b> 1 in contact with the substrate 12 of the sealant layer 24 is wider than the region A <b> 2 in contact with the sealing plate 14, and this widened region A <b> 1 is larger than the sealing plate 14. It is in a state where it protrudes to the outside. In other words, the area of the region A1 is larger than the area of the region A2.

  As described above, since the sealing agent layer 24 has the shape as described above, the substrate 12 and the sealing plate 14 are firmly bonded to each other, and stress is held inside the sealing agent layer 24. However, it is considered that cracks and the like are less likely to occur inside the sealant layer 24. For this reason, in the EL panel 110, the entry of outside air from cracks or the like is suppressed, and even when used for a long period of time, the reduction of the light emitting area is reduced. In addition, since the sealing agent layer 24 has the shape as described above, the substrate 12 and the sealing plate 14 are firmly bonded to each other, thereby improving the durability of the panel 110.

In the EL panel 110 of the present embodiment, the following formula:
R = 100 × (A1-A2) / A2
(In the above formula, A1 represents the area of the contact region between the substrate 12 and the sealing agent layer 24, and A2 represents the area of the contact region between the sealing plate 14 and the sealing agent layer 24).
Is preferably 0.020001% (= 200 ppm) or more. Below this value, cracks tend to occur when stress is maintained in the sealant layer 24. Further, the ratio R is preferably 400% or less for the reason of improving the life.

Furthermore, the following formula:
P = a / h × 100
(In the above formula, h represents the thickness of the sealing agent layer 24, and a represents the spread of the bottom of the sealing agent layer 24)
It is more preferable that the ratio P represented by is 10% or more. Here, when the contact area between the sealing plate 14 and the sealant layer 24 is projected onto the surface 12a of the substrate 12, the spread a of the bottom of the sealant layer 24 corresponds to the outer peripheral edge of the projected area, the substrate 12 and The difference with the outer periphery of the contact area | region of the sealing agent layer 24 is said. If P is less than 10%, cracks tend to occur when stress is maintained in the sealant layer 24. The ratio P is preferably 50000% or less for the purpose of improving the life.

  Note that the present invention is not limited to the panel having the structure described above, and can be appropriately changed without departing from the spirit of the present invention. For example, the EL element portion of the present invention is not limited to the above-described top emission type, and may be a bottom emission type EL element that extracts light emission from the substrate side. In this case, a color filter or a passivation film may be formed between the substrate and the EL element portion. Further, the panel is not limited to the above-described EL panel on which the organic EL element is mounted, and any panel including a light emitting element having a similar sealing structure such as an EL panel on which an inorganic EL element is mounted is not particularly limited. Is applicable.

  In the first and second embodiments, the sealing agent layer 24 has a shape that wraps around the edge 14 a of the sealing plate 14. It does not need to go around to the edge part 14a, and may have the shape where the surface 14b of the sealing board 14 and the outer peripheral surface 24a of the sealing agent layer 24 cross | intersect. That is, the area of the region A2 may be equal to or smaller than the area of the surface 14b of the sealing plate 14.

  Furthermore, in the said 1st Embodiment, area | region A1 which is in contact with the board | substrate 12 of the sealing agent layer 24 has spread rather than area | region A2 which is in contact with the sealing board 14, and this expanded area A1 is sealing board 14. However, the area of the region A1 may be equal to the area of the region A2, or may be smaller than the region A2.

  Furthermore, in the second embodiment, the region A1 in contact with the substrate 12 of the sealing agent layer 24 is wider than the region A2 in contact with the sealing plate 14, and this widened region A1 is the sealing plate. However, the area of the area A1 may be smaller than that of the area A2. In short, the area of the region A1 should not be equal to the area of the region A2.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.

Example 1
First, an organic EL element having an EL element portion provided on a substrate was formed. Next, a UV cation curable epoxy resin (XNR5570, manufactured by Nagase ChemteX Corporation) was dropped as a sealing agent on the substrate. Next, a transparent sealing plate was disposed so as to face the EL element portion, and these were pressed and bonded together to obtain a panel precursor.

Then, the obtained panel precursor is irradiated with ultraviolet light (output: 13000 mJ / cm ² ) emitted from a high-pressure mercury lamp from the sealing plate side to cure the UV cation curable epoxy resin as a sealing agent. An EL panel having a structure similar to that shown in FIG. 4 was obtained except that a sealant layer was formed and no color filter was provided.

  For the EL panel thus obtained, using an ultrasonic flaw detector (FineSAT made by Hitachi Construction Machinery Finetech), the interface between the substrate and the sealing agent layer and the interface between the sealing agent layer and the sealing plate are observed, Using the image of the interface, the area of the contact region between the substrate and the sealant layer and the area of the contact region between the sealant layer and the sealing plate were calculated. As a result, R = (A1-A2) / A2 = about 1000 ppm, and the area of the contact region between the substrate and the sealant layer is larger than the area of the contact region between the sealant layer and the sealing plate. I understood.

  Further, when the obtained EL panel was observed, it was confirmed that no cracks or peeling occurred in the panel.

(Comparative Example 1)
An EL panel was produced in the same manner as in Example 1 except that the UV cation curable epoxy resin as a sealing agent was dropped so that the sealing agent layer did not protrude from between the sealing plate and the substrate. I got a panel.

  For the EL panel thus obtained, the area of the contact region between the substrate and the sealing agent layer and the area of the contact region between the sealing agent layer and the sealing plate were calculated in the same manner as in Example 1. As a result, R = (A1-A2) / A2 = about 30 ppm, and it was found that the area of the contact region between the substrate and the sealing agent layer was almost equal to the area of the contact region between the sealing agent layer and the sealing plate. .

  Moreover, when the obtained EL panel was observed, some cracks were seen inside the panel.

[Luminescence test]
Using the obtained EL panels of Example 1 and Comparative Example 1, a light emission test was performed to measure a decrease in the light emitting region after light emission for a long time. That is, first, the EL panel immediately after manufacture was caused to emit light, and the area of the light emitting region was measured. Next, this light emission was continuously generated, and the area of the light emitting region was measured again after 800 hours. And the area of the light emission area | region after long-time light emission when the area of the light emission area | region immediately after manufacture was set to 100 was computed. The obtained results are shown in Table 1.

  From Table 1, it was found that the EL panel of Example 1 compared with the EL panel of Comparative Example 1 has a very small reduction in the light emitting region even after 800 hours of light emission, and can achieve a long life. Therefore, in an EL panel in which the area of the region in contact with either the substrate or the sealing plate is larger than the area of the region in contact with the other of the substrate or the sealing plate, It has been confirmed that even if no spacer is interposed between the sealing plate and the sealing plate, the reduction of the light emitting area can be sufficiently prevented.

It is a figure which shows typically the cross-section of the EL panel which concerns on one Embodiment of this invention. It is a figure which shows the planar structure of the EL panel shown in FIG. It is a figure which shows typically the cross-section of the principal part of an EL element part. It is a figure which shows typically the cross-section of the EL panel which concerns on other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... EL panel, 12 ... Board | substrate, 14 ... Sealing plate, 14a ... End edge part, 16 ... EL element part (light emitting element), 18 ... Color filter, 22 ... Spacer, 24 ... Sealing agent layer, A1, A2 ... region.

Claims (3)

A substrate,
A sealing plate disposed opposite to the substrate;
A light emitting device provided on the surface of the substrate facing the sealing plate;
A sealant layer that is disposed between the substrate and the sealing plate to bond them, and includes the light emitting element therein,
With
In the sealing agent layer, the area of the region in contact with one of the substrate and the sealing plate is larger than the area of the region in contact with the other of the substrate and the sealing plate. panel. The panel according to claim 1, wherein the sealing agent layer is formed so as to cover at least a part of an edge portion of at least one of the substrate and the sealing plate.   3. The panel according to claim 1, wherein the sealant layer is formed of a cured product of an adhesive composition having light retarding curability.

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