JP2008027815A - El panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EL panel having a sufficiently long life. <P>SOLUTION: This is the EL panel 1a which is provided with a substrate 3, an EL element 5 formed on the substrate 3, and a sealing part 7 that comes into contact with a face on a side where the EL element 5 of the substrate 3 is formed and that is installed so as to cover the EL element 5, and in which the sealing part 7 has a sealing layer 30 including a resin part 10 that is phase-separated into a first resin phase 11 and a second resin phase 12 and wherein a common continuous structure is formed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an EL (electroluminescence) panel.

The EL element is particularly vulnerable to moisture, and in order to extend its life, it is required to sufficiently prevent water from entering from the outside air environment. For this reason, a structure in which a sealing substrate is provided so as to cover the EL element formed on the substrate and the sealing substrate and the substrate are bonded together with an adhesive (sealing agent) is often used in EL panels. . In the EL panel having such a structure, the adhesion between the substrate and the adhesive layer is improved by sealing the EL element using an adhesive to which a coupling agent is added, and the interface between the substrate and the adhesive layer is improved. Attempts have been made to suppress water intrusion from water (for example, Patent Document 1).
JP 2005-213316 A

  However, the conventional EL panel has problems such as a decrease in luminance after long-term use, and further improvement has been demanded in terms of life. For example, as disclosed in Patent Document 1, the use of a coupling agent suppresses the water movement speed at the interface between the substrate and the adhesive layer to some extent, but it is still insufficient and there is room for further improvement.

  Accordingly, an object of the present invention is to provide an EL panel having a sufficiently long life.

  The present invention includes a substrate, an EL element formed on the substrate, and a sealing portion provided to contact the surface of the substrate on which the EL element is formed and to cover the EL element, The sealing part is an EL panel having a sealing layer containing a resin part in which a co-continuous structure is formed by phase separation into a first resin phase and a second resin phase.

  The EL panel of the present invention has a sufficiently long life because the co-continuous structure of the resin is formed in the sealing layer. It is considered that the water that has entered the sealing layer tends to move along the interface between the first resin phase and the second resin phase. And since the co-continuous structure is formed, the area of an interface is large and the path | route when water moves along this becomes long. As a result, it is considered that the arrival of water to the EL element is delayed and the life of the EL panel is prolonged.

  The sealing layer preferably further contains an inorganic filler dispersed so as to be unevenly distributed in the first resin phase in the resin portion. Thereby, the effect of extending the life of the EL panel can be obtained more remarkably.

  According to the present invention, an EL panel having a sufficiently long life is provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In addition, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted suitably.

  FIG. 1 is a schematic sectional view showing an EL panel according to the first embodiment of the present invention. 1 includes a substrate 3, an EL element 5 formed on the substrate 3, and a sealing provided to cover the EL element 5 on the side of the substrate 3 where the EL element 5 is formed. Part 7. The sealing portion 7 is in contact with the surface of the substrate 3 on the EL element 5 side and is in close contact with the EL element 5 while covering the sealing layer 30 with the sealing layer 30 interposed therebetween. And a sealing substrate 40 arranged opposite to each other. The distance d between the substrate 3 and the sealing substrate 40 is usually about 0.5 to 50 μm.

  The EL panel 1a can be applied as an EL panel of either a top emission type that displays light emitted from the EL element 5 on the sealing portion 7 side or a bottom emission type that displays light on the substrate 3 side. .

  The sealing layer 30 is unevenly distributed in the first resin phase 11 in the resin portion 10 in which the co-continuous structure is formed by phase separation into the first resin phase 11 and the second resin phase 12. And the inorganic filler 20 dispersed as described above.

  The resin part 10 having a co-continuous structure can be formed, for example, by curing a curable resin composition containing a curable resin and a thermoplastic resin or an elastomer. In this case, as will be described later, by appropriately selecting the type of the curable resin and the thermoplastic resin or elastomer to be combined therewith, the first resin phase mainly composed of the cured resin derived from the curable resin and Then, phase separation into a second resin phase mainly composed of a thermoplastic resin or an elastomer forms a co-continuous structure.

  When the first resin phase 11 is a phase derived from an epoxy resin, the second resin phase 12 is generally a more hydrophobic phase than the first resin phase 11. In this case, the more hydrophilic first resin phase 11 allows water to penetrate more easily than the hydrophobic second resin phase 12. However, even in this case, since the inorganic filler 20 is unevenly distributed in the first resin phase 11 as in the present embodiment, the water penetration rate can be more effectively delayed with a smaller amount of the inorganic filler 20. Can do. When the amount of the inorganic filler 20 is small, it is advantageous in terms of improving the luminance particularly in the case of the top emission type.

  As the inorganic filler 20, an inorganic filler having a plate shape, a needle shape, a spherical shape, or the like can be used. Of these, a plate-like or needle-like inorganic filler is preferable. Specific examples of the inorganic filler 20 include talc and silica particles.

  In the present embodiment, substantially all of the inorganic filler 20 is present in the matrix 11, but the present invention is not limited to such a distribution, and the inorganic filler 20 includes the first resin phase 11 and the second resin phase. 12 may be evenly distributed. However, it is preferable that the inorganic filler 20 is dispersed in the resin portion 10 in a state where the number of the inorganic fillers 20 is distributed so that the first resin phase 11 is larger than the second resin phase 12. More specifically, 70% or more of the total number of inorganic fillers in the sealing layer is preferably present in the first resin phase. Note that the sealing layer preferably contains an inorganic filler from the viewpoint of improving the life of the EL panel, but the sealing layer does not necessarily contain an inorganic filler.

  The board | substrate 3 and the sealing substrate 40 are suitably selected from what is normally used as a board | substrate of EL panel. When the EL panel 1a is used as a top emission type, at least the sealing substrate 40 of the substrate 3 and the sealing substrate 40 is made of a light-transmitting material. When the EL panel 1a is used as a bottom emission type, at least the substrate 3 of the substrate 3 and the sealing substrate 40 is made of a light-transmitting material. Examples of the light-transmitting material include glass and transparent plastic.

  The EL element 5 has a laminated structure in which an EL layer composed of an organic EL material or an inorganic EL material is sandwiched between a pair of electrode layers. As the EL element 5, an element appropriately selected from conventionally known elements can be used.

  FIG. 2 is a schematic sectional view showing an EL panel according to the second embodiment of the present invention. The EL panel 1b shown in FIG. 2 has the same configuration as the EL panel 1a except for the structure of the sealing portion 7.

  The sealing substrate 40 included in the sealing portion 7 in the second embodiment has a shape in which a portion extending toward the substrate 3 is formed at the peripheral edge portion. A sealing layer 30 is formed between the extended portion and the main surface of the substrate 3, and the sealing portion 7 covers the EL element 5 so that a hollow space is formed by this and the substrate 3. Yes. This hollow space is filled with an inert gas.

  The EL panels 1a and 1b include, for example, an EL element forming process for forming the EL element 5 on the substrate 3, and a sealing portion that covers the EL element 5 on the surface of the substrate 3 on which the EL element 5 is formed. A sealing part forming step to be formed, and the sealing part forming step hardens the curable resin composition on the substrate 3 and phase-separates into the first resin phase 11 and the second resin phase 12. Forming a sealing layer 30 containing the resin part 10 in which the co-continuous structure is formed and the inorganic filler 20 dispersed so as to be unevenly distributed in the first resin phase 11 in the resin part 10. Obtained by the production method.

  As understood by those skilled in the art, the EL element 5 can be formed on one surface of the substrate 3 by a conventionally known method. It is preferable that the EL element formation step and the sealing portion formation step subsequent thereto be performed in a low humidity atmosphere substantially consisting of only an inert gas.

  The curable resin composition used in the sealing portion forming step contains, for example, a curable resin, a thermoplastic resin or elastomer, an inorganic filler, and other components as necessary.

  The curable resin is a resin made of a monomer, an oligomer, a prepolymer, or the like that forms a crosslinked structure by heating or light irradiation and is cured. An epoxy resin such as a bisphenol A type epoxy resin is preferably used as the curable resin. In this case, an epoxy resin curing agent, a curing accelerator, and the like are added to the curable resin composition. A hardening | curing agent or hardening accelerator is suitably selected from what is normally used as what advances hardening of an epoxy resin by a heating or light irradiation.

  When an epoxy resin is used as the curable resin, the thermoplastic resin or elastomer that can be combined with the epoxy resin to form a co-continuous structure includes polyethylene hexahydrophthalate, polyester, polysulfone, polyetherketone, polyethersulfone. , Ether imide, polyphenylene sulfide, polyether ether ketone, polyacetal, polycarbonate, phenoxy resin, polystyrene, polyethylene, polybutadiene rubber, polyacrylate, polyoxybenzoate, polyvinyl chloride, polyvinyl acetate, and their copolymerization ratio is 50 mol% The copolymer which is the above is mentioned.

  In the sealing portion forming step, for example, a curable resin composition is applied onto the substrate 3 or the sealing substrate 40 and sandwiched between the substrate 3 and the sealing substrate 40. The sealing layer 30 is formed by curing the curable resin composition sandwiched between the substrate 3 and the sealing substrate 40 by light irradiation or heating. At this time, the curable resin composition is preferably cured by further heating after light irradiation. When curing, the whole is pressurized as necessary.

  In addition, an EL panel is manufactured through a process normally performed in manufacturing an EL panel.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

Example 1
A bisphenol A type epoxy resin, methylhexahydrophthalic acid as a curing agent, and polyethylene hexahydrophthalate (weight average molecular weight 14000) were mixed with a homogenizer to prepare an epoxy resin composition. The ratio of polyethylene hexahydrophthalate was 30% by mass with respect to the entire epoxy resin composition.

  The obtained epoxy resin composition was applied to a glass substrate, bonded to a substrate on which an organic EL element was formed, in an inert gas atmosphere, and the whole was pressed at a pressure of 0.4 MPa. And the epoxy resin composition was hardened by heating at 120 degreeC for 4 hours, and the EL panel which has the sealing layer formed from the epoxy resin composition was obtained. When the cross section of the sealing layer was observed by SEM, it was confirmed that the resin was phase-separated into two phases to form a co-continuous structure.

Example 2
A bisphenol A type epoxy resin, methylhexahydrophthalic acid as a curing agent, polyethylene hexahydrophthalate (weight average molecular weight 14000), and talc as an inorganic filler are kneaded with three rolls to obtain an epoxy resin composition. Prepared. The ratio of polyethylene hexahydrophthalate was 30% by mass relative to the mass of the epoxy resin composition excluding talc.

  An EL panel was produced in the same manner as in Example 1 using the obtained epoxy resin composition. When the cross section of the formed sealing layer was observed with SEM, it was confirmed that a co-continuous structure was formed and talc was unevenly distributed in the phase derived from the epoxy resin.

Comparative Example An EL panel was produced in the same manner as in Example 1 except that an epoxy resin composition prepared by mixing bisphenol A type epoxy resin and methylhexahydrophthalic acid as a curing agent was used.

Evaluation of EL Panel For each of the EL panels obtained as described above, the luminance at the initial stage and after 1000 hours of light emission was measured. The results are shown in Table 1.

  As shown in Table 1, the luminance of the comparative EL panel having a sealing layer formed from a uniform resin phase was greatly reduced after 1000 hours. On the other hand, the EL panel of the example having the sealing layer in which the co-continuous structure was formed maintained sufficiently high luminance even after 1000 hours.

It is a schematic sectional drawing which shows the EL panel which concerns on 1st embodiment of this invention. It is a schematic sectional drawing which shows the EL panel which concerns on 2nd embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a, 1b ... EL panel, 3 ... Board | substrate, 5 ... EL element, 7 ... Sealing part, 10 ... Resin part, 11 ... 1st resin phase, 12 ... 2nd resin phase, 20 ... Inorganic filler, 30 ... Sealing layer, 40 ... sealing substrate.

Claims (2)

A substrate, an EL element formed on the substrate, and a sealing portion provided to contact the surface of the substrate on which the EL element is formed and to cover the EL element,
The sealing portion includes an sealing layer including a sealing portion including a resin portion in which a co-continuous structure is formed by phase separation into a first resin phase and a second resin phase.   The EL panel according to claim 1, wherein the sealing layer further contains an inorganic filler dispersed so as to be unevenly distributed in the first resin phase in the resin portion.

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