The present invention relates to a technology of sealing of organic electroluminescence (EL) display device or lighting device and sealants.
Though organic EL display devices with a superior picture quality than liquid crystals and lower power consumption are expected to be the dream panels, the technology for extending the life and increasing the screen size was difficult which has been causing a delay in commercialization. Organic EL display devices, and their light emission principles are well known, and the technology for making their energy consumption extremely low to protect the earth environment is progressing. However, organic EL elements are sensitive to moisture, and organic EL elements are easily prone to degradation and deterioration by moisture. As a result, a decline in quantum efficiency is accelerated, and the life is said to be about 10,000-20,000 hours. That is, the degradation and deterioration of organic EL elements by moisture have made mass production of organic EL display devices difficult.
However, in such a technology, there used to be permeation of air or moisture from the adhesive 17, the substrate plate 12 and the sealing case 13, and due to degradation of the organic EL element 16, there were many instances of failure to emit light. To prevent this, a drying agent was provided between the substrate plate 12 and the sealing case 13. However, as the absorption efficiency depends on the material used, it was not possible to realize a performance beyond the absorption efficacy. For example, with a drying agent, only a maximum of about 20000 hours could be guaranteed. With this, if moisture absorption of the drying agent is not possible, the organic EL element 16 deteriorates, and as the number of light emitting elements of the organic EL display device 11 becomes less, the life of the panel itself is shortened. In particular, since the reliability of a panel is affected by natural environmental conditions such as temperature condition, humidity condition and atmospheric condition under which the organic EL display device 11 is used, it was difficult to guarantee a high reliability of the organic EL display device 11.
The present invention solved this problem by sealing the entire organic EL display device or lighting device, and realized prolonging the life of the organic EL element.
That is, the entire organic EL display panel is covered by sealing the top and bottom, left and right, front and back, and the entire periphery of the panel with an air-impermeable resin. Or, by dipping the substrate plate into the resin or printing the resin onto the substrate plate excluding the display part and light emitting part of the organic EL panel, it is possible to block air and moisture which affect the life of the organic EL element. The present invention intends to extend the life of organic EL panel by this approach.
Specifically, the organic EL display device of the first embodiment of this invention has a transparent substrate plate, an organic EL element provided on one side of the substrate plate and a terminal for applying relevant voltage to the organic EL element, and involves completely sealing the organic EL display device with a sealant.
The sealing material for completely sealing the organic EL display device is a transparent sealing material. Further, the sealing material used for sealing the whole organic EL display device seals the entire body as well as the periphery of the display device. In this case, it is also possible to have a configuration wherein the entire body and the periphery are sealed with a sealing material while excluding the terminal. The organic EL display device may be further provided with a sealing case installed opposite to the substrate plate, and the substrate plate and the sealing case can be secured by providing an adhesive containing glass pieces of length not greater than 10 μm in the gap between the substrate plate and the sealing case. This transparent sealing material may even completely cover the sealing case. Further, the organic EL display device may be provided with a spacer between the inner surface that has been sealed with the sealing material and the substrate plate or the sealing case, and at least one drying agent may also be provided in the space between the spacer and the substrate plate or the sealing case.
The second embodiment of this invention provides an organic EL display device including: a substrate plate; an organic EL element provided on the substrate plate; a sealing case provided on the side opposite to the side where the organic EL element is provided on the substrate plate; a first sealant provided between the sealing case and the substrate plate; a terminal connected to the organic EL element for applying electrical voltages to the terminal; the end section of the organic EL display device is sealed with a reinforcing material; and the said reinforcing material is further sealed with a plurality of layers of a second transparent sealant. The first sealant may be prepared by mixing finely crushed glass with a pure resin. From the point of characteristics also, it is preferable that the finely crushed glass has a length not greater than 10 μm. The reinforcing material for reinforcing the end section of the organic EL display device may be provided on the periphery of the organic EL display device. The reinforcing material that reinforces the end section of the organic EL display device may be formed from metal, glass or resin. Moreover, the reinforcing material that reinforces the end section of the organic EL display device may also be provided on a part of the periphery of the organic EL display device. It is also possible to provide the second sealant out of a region in which the organic EL element is formed. A drying agent may also be set inside or outside the reinforcing material.
The third embodiment of this invention provides an organic EL lighting device including: a substrate plate; an organic EL element provided on one side of the substrate plate; a terminal for applying electrical voltages to the organic EL element; and the vertical and lateral surfaces of this organic EL display device are completely sealed with a transparent or translucent sealant.
In this case, excluding the terminal section, the entire surface is sealed with a transparent or a translucent sealant. The organic EL display device may be further provided with a sealing case opposite to the substrate plate, and an adhesive-based sealant may be provided between the substrate plate and the sealing case. The sealing case may also be covered with transparent or translucent sealant. The adhesive-based sealant may be prepared by mixing finely crushed glass with a pure resin, wherein the finely crushed glass shall have a length not greater than 10 μm.
Below is an overview of various aspects of the invention:
According to one aspect of the present invention, the organic EL display panel includes a transparent substrate, an organic EL element provided on a first side of the substrate, and a sealing case made of metal. The metallic sealing case is provided on the first side of the substrate so that it faces the organic EL element. The organic EL display panel further includes a terminal for applying voltage to said organic EL element and a sealant which covers an entire surface of the organic EL display panel.
In this embodiment the terminal has an interior part between the sealing case and the transparent substrate and an exterior part exterior to said substrate. In addition, the organic EL display panel includes an adhesive containing glass pieces which are not greater than 10 μm in length for securing the transparent substrate to the metalic sealing case.
According to yet another aspect of the present invention, the organic EL display panel includes a transparent substrate and an organic EL element provided on a first side of the substrate. In addition, a sealing case is provided on the first side of the substrate so that it faces said organic EL element. The organic EL display panel further includes a terminal for applying voltage to said organic EL element. Moreover, a first sealant, as an adhesive, is provided between said sealing case and said transparent substrate. A reinforcing material adjacent to an end section of the organic EL display panel is also provided, where the reinforcing material is made of the same material as that of the first sealant. Furthermore, a second sealant covers at least said reinforcing material, where the second sealant is made of a transparent material.
In this embodiment, the second sealant is a thin film encapsulation layer and the first sealant is obtained by mixing finely crushed glass pieces, having a length not greater than 10 μm, with a pure resin.
According to yet another embodiment, the second sealant further covers an entire surface of the organic EL display panel.
According to yet another embodiment, the organic EL display panel further includes a spacer between the second sealant and both of said substrate and sealing case, where the spacers are made of glass.
A process for sealing an organic EL display panel or lighting device according to embodiments of the present invention includes the steps of: (1) depositing an organic EL element on a substrate; (2) laminating a metal sealing case to the substrate using a first sealant, wherein the metal sealing case is facing said organic EL element; (3) vacuum-depositing a reinforcing material to an end section of said organic EL display panel or lighting device so that the reinforcing material is integrated with the first sealant to form one part; and (4) depositing a thin film encapsulation layer covering an entire surface of said organic EL display panel or lighting device and that of said reinforcing material.
According to one embodiment of the present invention, the step of depositing the thin film encapsulation layer is carried out by: (1) depositing a polymeric decoupling layer on the entire surface of said organic EL display panel or lighting device and that of said reinforcing material; (2) depositing a first inorganic layer on the polymeric decoupling layer under a first set of conditions so that said first inorganic layer is not a barrier layer; and (3) depositing a second inorganic layer on the first inorganic layer under a second set of conditions so that said second inorganic layer is a barrier layer.
The first set of conditions are set so that an ion and neutral energy arriving at the substrate is less than about 20 eV and a temperature of the substrate is less than about 150° C. While, the second set of conditions are set so that an ion and neutral energy arriving at the substrate is greater than about 50 eV.
In this embodiment, the polymeric decoupling layer is selected from acrylates, thiols, epoxies, polyesters, siloxanes, urethanes, or combinations thereof. On the other hand, the inorganic non-barrier layer, the inorganic barrier layer or both are selected from metals, metal oxides, metal fluorides, metal nitrides, metal carbides, metal carbonitrides, metal oxynitrides, metal borides, metal oxyborides, metal silicides, or combinations thereof.
According to yet another embodiment, the inorganic non-barrier layer or the inorganic barrier layer or both are selected from aluminum oxides, aluminosilicates, silicon oxynitrides, silicon nitrides, silicon oxides, or combinations thereof.
According to yet another embodiment, the inorganic non-barrier layer or the inorganic barrier layer are made of different materials.
The first sealant used in laminating step is an adhesive containing glass pieces not greater than 10 μm in length that secures the transparent substrate to the sealing case.
The present disclosure is described in conjunction with the appended figures:
Here, the organic EL display device 1 is one kind of flat panel types. Cathode and anode are formed into a stripe form. An organic EL element 6, which is formed from organic material, is provided in a section where cathode and anode intersect as an image element in the organic EL display device 1. Here, the organic material is a molecular compound comprised of carbon as the major constituent, nitrogen, oxygen and hydrogen.
The transparent plate 2 is a substrate plate such as glass plate etc., and the organic EL element 6 in a matrix shape is provided on the substrate plate. Apart from glass plate, various materials such as acrylic material, resin or film etc., can be used for the transparent plate 2.
The sealing case 3 is a case made of metal which is separate from the organic EL element 6. The metallic sealing case 3 is provided for protecting the organic EL element 6, which is disposed on the transparent plate 2, from external atmosphere. As explained earlier, organic EL element 6 is sensitive to moisture, and easily prone to degradation and deterioration by moisture. This hastens a decrease in the quantum efficiency resulting in a shortening of the life of the organic EL display device 1. Therefore, the intrusion of moisture to the organic EL element 6 provided on the transparent substrate plate 2 is prevented by this sealing case 3.
The terminal 4 for applying voltage to the organic EL element 6 is a connection terminal using copper foil, lead wires, metal fittings for terminal etc. The terminal 4 passes current by externally applying a voltage of few volts to the organic EL element 6, and causes the organic thin film to emit light. By injecting current to the organic EL element 6, the organic molecule is shifted to an excited state, and when the organic molecule returns to the initial ground state, excess energy is released as lights, and the organic molecule in the organic EL element 6 emits lights. As shown in more detail in
In this embodiment, as for a sealant 5, a transparent and pure resin is used as a sealing material. This is because using a resin containing impurities, irrespective of the conducting or non-conducting impurities, the sealant 5 weakens the material against the breakdown voltage of the organic EL element 6. Specifically, an uncured sealing resin is applied in the entire periphery of the organic EL display device 1 by using processes such as dipping or printing or other methods, and then the sealing resin is cured. Still, although an uncured sealing resin is applied on the entire periphery of the organic EL display device 1 in this embodiment, it is also possible to provide a coating only in areas excluding the emitting surface and display surface of the organic EL display device 1 to obtain a higher intensity.
Taking the case of coating the entire periphery as an example, the thickness of uncured resin sealant 5 can be adjusted with a thickness-adjusting tool, and the uncured resin sealant 5 is coated over the entire panel. Then, it is inverted, and the opposite side is also coated similarly. The entire periphery is coated by also coating the sides. When not coating on the emitting surface and display surface, coating is provided on one side by adjusting the thickness of uncured resin sealant 5 with a thickness-adjusting tool as in case of coating on the entire periphery. Coating is provided on the sides, by excluding emitting surface and display surface, as in the coating of the entire periphery. However, coating of the sealant 5 is not restricted to this method, and various modifications are possible.
In this embodiment, the sealant 5, which seals the whole organic EL display device 1, seals the whole body as well as the periphery of the display device by a sealing material. With this, it makes possible not to allow intrusion of air and moisture, and thus prevent any adverse effect on the organic EL element 6. Even the terminal 4 is coated with the sealant 5 by providing the lead wires to the terminal 4. However, it may have a configuration in which coating of the sealant 5 is performed on the display device excluding the terminal 4.
The sealant 5 is a thin film encapsulation layer covering the entire surface of the organic EL display device 1. As shown in
The inorganic non-barrier layer 5b-1 is formed under a first set of conditions where an ion and neutral energy arriving at the substrate is less than about 20 eV and a temperature of the substrate is less than about 150° C. On the other hand the inorganic barrier layer 5b-2 is formed under a second set of conditions where the ion and neutral energy arriving at the substrate is greater than about 50 eV. In this embodiment, the composite inorganic layer 5b includes two separate layers: one inorganic non-barrier layer 5b-1 and one inorganic barrier layer 5b-2. It should be noted that the substrate indicated in the first and second set of conditions may include, but is not limited to, an organic EL display device or an organic EL lighting device which are used in our sealing process.
Other embodiments may include one inorganic layer 5b formed on the polymeric decoupling layer 5a where a first portion of the inorganic layer 5b, which is adjacent to the polymeric decoupling layer, is not a barrier layer while a second portion of the inorganic layer is a barrier layer. In this case, the first portion of the inorganic layer is formed under a first set of conditions where an ion and neutral energy arriving at the substrate is less than about 20 eV and a temperature of the substrate is less than about 150° C. After a desired thickness of the first portion of the inorganic layer 5b has been reached, changing to the second set of conditions forms the second portion of the inorganic barrier layer 5b where an ion and neutral energy arriving at the substrate is greater than about 50 eV.
Examples of polymers used in the polymeric decoupling layer 5a may include, but are not limited to, acrylates, thiols, epoxies, polyesters, siloxanes, urethanes, or combinations thereof. The inorganic layer 5b may be any suitable barrier material. Suitable inorganic materials based on metals include, but not limited to, individual metals, two or more metals as mixtures, intermetallics or alloys, metal oxides, metal fluorides, metal nitrides, metal carbides, metal carbonitrides, metal oxynitrides, metal borides, metal oxyborides, metal silicides, or combinations thereof. Metals includes but not limited to aluminum, indium, germanium, tin, antimony and bismuth, and combination thereof. Many of the resultant metal based materials will be conductors or semiconductors. Suitable inorganic materials based on p block semiconductors and non-metals include, but are not limited to, silicon and silicon compounds. It should be noted that the non-barrier and barrier inorganic layers may be made of the same material or a different material.
However, it is also possible to constitute either the substrate plate 2 or the sealant 5 or both from translucent or opaque members.
In this embodiment, which is different from the above embodiment, a sealing case 3 has been provided. As described above, the sealing case 3 is made of metal and is separate from the organic EL element 6 which is disposed on the transparent substrate plate 2. As is known in the art, the organic EL element 6 is sensitive to moisture, and therefore is easily susceptible to degradation and deterioration by moisture. The intrusion of moisture into the organic EL element 6 is prevented by the metallic sealing case 3. In this embodiment, the sealant 5 is provided to completely envelope the sealing case 3. With such a configuration, the intrusion of moisture to the organic EL element 6 can be prevented to a great extent.
Further, the substrate plate 2 and the sealing case 3 are secured by providing between the substrate plate 2 and the sealing case 3 an adhesive 7 containing glass pieces of length not greater than 10 μm. With this, the intrusion of moisture through the gap between substrate plate 2 and sealing case 3 can be prevented, and the lifetime of the organic EL display device 1 can be improved. The adhesive 7 includes of a pure resin mixed with finely crushed glass pieces of length not greater than 10 μm. With this, compared to the resin-based adhesives used conventionally, the intrusion of oxygen and moisture to the organic EL element 6 can be further prevented by preserving the characteristics of glass.
In this embodiment, in addition to securing the substrate plate 2 and the sealing case 3 by providing the adhesive 7 containing glass pieces of length not greater than 10 μm between the substrate plate 2 and the sealing case 3, the entire body of the substrate plate 2 and the sealing case 3 is sealed with a transparent sealant 5. With this, the intrusion of moisture to the organic EL element 6 can be prevented to a very great extent, and the degradation or deterioration of the organic EL element 6 due to moisture can be greatly controlled. By significantly improving the deterioration or degradation of the organic EL element due to moisture, mass production of a long-life organic EL display device 1 becomes easy.
In this embodiment, the end part of the organic EL display device 1 is sealed with reinforcing materials 8A and 8B, and further sealed with a plurality of layers of a transparent second sealant 5 provided by covering the reinforcing materials 8A and 8B. With such a configuration, contamination of the organic EL element 6 by external atmosphere can be prevented apart from greatly improving the strength of the organic EL display device 1. It is also possible to make the organic EL display device 1 thin.
The first sealant or adhesive 7 is a sealant prepared by mixing a pure resin with finely crushed glass. The finely crushed glass is characterized by having a length not greater than 10 μm and by maintaining the characteristics of glass, compared to the conventionally used resin-based adhesives, the intrusion of oxygen and moisture to the organic EL element 6 can be effectively prevented.
The reinforcing materials 8A and 8B for reinforcing the end section of the organic EL display device 1 are made from metal, glass or resin, and provided in the periphery of the organic EL display device 1. In some embodiments, the reinforcing materials 8A and 8B are made from the same material as that of the first sealant 7. In addition, with satisfactory strength, the reinforcing materials 8A and 8B that reinforce the end section of the organic EL display device 1 may also be provided in a part of the periphery of the organic EL display device 1. This working example is explained with
In this working example, by providing spacers 9A and 9B, the drying efficiency can be greatly improved by plural installations of the drying agent between the substrate plate 2 and the spacer 9A or the sealing case 3 and the spacer 9B. For example, when guaranteeing a maximum of 20000 hours with one drying agent, the guaranteed period can be increased to such as 40000 hours, 60000 hours etc. by installing the drying agent in multiple numbers such as 2, 3 etc., respectively. Therefore, in addition to providing a drying agent between either the substrate plate 2 and the space 9A or the sealing case 3 and the spacer 9B or both, the drying agent may also be provided in single, double, or triple layers.
The drying agents 10A and 10B in this example may also be used in other working examples. In particular, the drying agents 10A and 10B can be used in the configurations illustrated in
It is also possible to protect the emitting region required for display. Or, if large amounts of drying agent are necessary, the entire outer periphery of the organic EL display device 1 may be enclosed with the drying agent 10A and 10B. It is also possible to integrate the drying agents 10A and 10B with the reinforcing materials 8A and 8B, or to provide the reinforcing materials 8A and 8B outside the drying agents 10A and 10B. In particular, major portion of moisture from the organic EL element 6 can better be absorbed by providing the drying agent within the reinforcing material. However, from the view point of ease of manufacturing of the organic EL display device 1, it is preferable to install the drying agent outside the reinforcing material as shown in
In the following, the process used for sealing organic EL display panel or lighting devices according to the embodiment described in
The step of depositing the thin film encapsulation layer 5 may start by depositing a polymeric decoupling layer on the entire surface of the organic EL display panel or lighting device and that of said reinforcing material. After forming the decoupling layer, an inorganic non-barrier layer is formed on the polymeric decoupling layer under a first set of conditions. Next, an inorganic barrier layer is formed on the inorganic non-barrier layer under a second set of conditions. The first and second sets of conditions are defined according to the conditions described in paragraphs [0021] and [0036].
The third embodiment of the present invention relates to an organic EL lighting device. An organic EL lighting device, unlike incandescent bulb or fluorescent tube, can be used as a very thin and small source of light, and as it can illuminate a wide area because of surface emission unlike a LED (Light-Emitting Diode), it is being anticipated as a next generation light source.
The third embodiment of this invention provides an organic EL lighting device 1 provided with: a substrate plate 2; an organic EL element 6 provided on one side of the substrate plate 2; a terminal 4 for applying voltage to the organic EL element 6; and the vertical and lateral surfaces of this organic EL display device 1 are completely sealed with a transparent or translucent sealant 5.
The organic EL lighting device 1 of this embodiment may have all the configurations illustrated in
In organic EL lighting device 1, a configuration shown in
As explained above, it is possible to suitably vary the various members and configuration elements in the organic EL display device and the organic EL lighting device of these examples. For example, to realize a lighting device to illuminate a wide area, appropriate modifications are possible to manifest the advantages of the surface emission, such as making the profile of the sealant 5 towards the display surface as a smooth tapered profile.
In addition, this invention can also be applied to organic semiconductors, organic solar panels etc. In these cases, since the performance can be satisfactorily obtained even without a drying agent, it is also possible to adopt a configuration that does not require the drying agents 10A and 10B.
While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the invention.
This application is a continuation-in-part of application Ser. No. 12/807,860, filed Sep. 14, 2010, entitled Sealing for Panels of an Organic Electroluminescence Display and Lighting Apparatus, which is hereby expressly incorporated by reference in its entirety for all purposes.
Number | Date | Country | |
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Parent | 12807860 | Sep 2010 | US |
Child | 13935435 | US |