Particle holding sheet, method of manufacturing particle holding sheet and organic electroluminescent display having particle holding sheet

Moisture absorbent is embedded in a sheet-type support by a centrifugal force. A gas permeable sheet is fixed to one face of the support via an adhesive layer and a protection sheet is fixed to the other face of the sheet-type support via an adhesive layer. In this way, a moisture absorbent sheet is previously prepared. When in an organic EL display, the protection sheet is removed from the moisture absorbent sheet, the adhesive layer comes into contact with an opposed face of a seal cap and the moisture absorbent sheet is fixed to the opposed face. The seal cap is put on a transparent insulating substrate in which an anode layer, organic EL lamination body, and a cathode layer are laminated. The seal cap comes into contact with the transparent insulating substrate via seal resin of ultraviolet-curable type and ultraviolet rays are irradiated so as to complete the organic EL display.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a particle holding sheet, a method of manufacturing the particle holding sheet and an organic EL (ElectroLuminescent) display having the particle holding sheet, and more particularly, relates to an moisture absorbent sheet, a method of manufacturing the moisture absorbent sheet and an organic EL display, suitable for removing moisture in a sealed space using an moisture absorbent as a particle when the organic EL elements are hermetically sealed by adhering a substrate on which organic EL elements are formed to a seal cap in the organic EL display. Hereafter, the present invention will be explained using the moisture absorbent sheet and the organic EL display having the moisture absorbent sheet, however, particles are not limited to the moisture absorbent in the present invention.

The present application claims priority of Japanese Patent Application No. 2001-111948 filed on Apr. 10, 2001, which is hereby incorporated by reference.

2. Description of Related Art

An organic EL (ElectroLuminescent) display element has a structure in which a luminescent layer made of an organic compound is put between an anode and a cathode. By applying a direct voltage to the anode and the cathode of the organic EL display element, holes injected from the anode and electrons injected from the cathode are recombined in the luminescent layer to make an excitation state. Then, luminescence occurs in a relaxation process from the excitation state to a ground state.

The organic EL display has good characteristics which cannot be provided by a liquid crystal display, for example, the organic EL display can be a self-luminescent thin flat display with a rapid response ability and a wide angle of visibility.

However, since the organic EL element deteriorates by moisture infiltration, a sufficient lifetime can not be obtained. For example, with the moisture penetrating an interface between the luminescent layer and an electrode, the electrons are prevented from injecting. Therefore, a display quality is deteriorated since a dark spot which is a non-luminescent area generates in the luminescent layer, the electrode corrodes and the dark spot grows to reduce the luminescent area.

Therefore, it is considered that influences of the moisture and a like are prevented by hermetically sealing the organic EL element. For example, an organic EL display is proposed in which the organic EL element is enclosed in a container having no moisture permeability with nitrogen gas and moisture absorbent.

An organic EL display101, as shown inFIG. 14, is provided with a transparent insulating substrate102such as a glass substrate, an anode layer103, an organic EL lamination body104including a luminescent layer, a cathode layer105and a seal cap106. A moisture absorbent107is stored in a concave portion106aformed in the seal cap106.

The anode layer103is formed on the transparent insulating substrate102and is made of transparent conductive material such as ITO (Indium Tin Oxide).

The organic EL lamination body104, for example, as shown inFIG. 14, includes a hole transport layer108, a luminescent layer109and an electron transport layer110, in that order, on the anode layer103.

The hole transport layer108is made of TPD: N,N′-diphenyl-N,N′-di(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine or alike.

The luminescent layer109is made of Alq3: tris (8-hydroxyquinolinol) Aluminum. The electron transport layer110is made of 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole or a like.

The cathode layer105is formed on the organic EL lamination body104and is made of aluminum or a like.

The seal cap106is made of metal material such as stainless steel, glass, or a like and seals the anode layer103, the organic EL lamination body104, and the cathode layer105. The seal cap106has the concave portion106afor keeping the moisture absorbent107and is put on the transparent insulating substrate102to cover the anode layer103, the organic EL lamination body104, and the cathode layer105via a seal resin111.

The moisture absorbent107is composed of particles such as BaO and is held by a gas permeable sheet112while being kept in the concave portion106aof the seal cap106.

A method of manufacturing the organic EL display101will be explained.

First, the anode layer103such as ITO is formed on the transparent insulating substrate102such as a glass substrate by a sputtering technique or a like. On the transparent insulating substrate102on which the anode layer103is formed, N,N′-diphenyl-N,N′-di(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine) or a like, tris (8-hydroxyquinolinol) aluminum or a like, 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole or a like are deposited by an evaporation technique. With these processes, the organic EL lamination body104including the hole transport layer108, the luminescent layer109and the electron transport layer110is formed.

Then, the cathode layer105such as aluminum is formed on the organic EL lamination body104by the evaporation technique using a shadow mask.

As shown inFIG. 15A, the seal cap106in which the concave portion106ais formed is prepared, as shown inFIG. 15B, the moisture absorbent107is stored in the concave portion106aof the seal cap106and, as shown inFIG. 15C, the moisture absorbent107is covered with the gas permeable sheet112so as to be held.

The seal resin111of an ultraviolet-curable type is coated on a lower end face of a side wall of the seal cap106which holds the moisture absorbent107. Then, under an inert gas atmosphere such as nitrogen gas or argon gas, the seal cap106is put on the transparent insulating substrate102and a side wall end face106bof the seal cap106is jointed to the transparent insulating substrate102via the uncured seal resin111.

Then, ultraviolet rays are irradiated from the side of the transparent insulating substrate102so as to cure the seal resin111. Therefore, the organic EL lamination body104is sealed by the seal cap106while being filled with inert gas such as nitrogen gas or argon gas. With these processes, the organic EL display101is completed.

However, in the conventional technique, there is a problem in that it takes time to store the moisture absorbent107in the step of keeping the moisture absorbent107in the concave portion106aof the seal cap106.

In other words, since the moisture absorbent107is composed of particles which are apt to be electrified. When the moisture absorbent107is stored in the concave portion106aof the seal cap106, the moisture absorbent107flies and overflows. Therefore, there are problems in that it is difficult to store an accurate amount of the moisture absorbent107certainly and in that an operation is complicated and it takes a great amount of working time.

Also, since the concave portion106afor storing the moisture absorbent107is formed in the seal cap106, a thickness of the seal cap106is bigger. Therefore, there is another problem in that the organic EL display is prevented from being thin and small as a whole.

Additionally, these problems also occur in a solar battery module or a like which is necessary to have moisture resistance, and therefore are not only limited to the organic EL display.

SUMMARY OF THE INVENTION

In view of the above, it is a first object of the present invention to provide a moisture absorbent sheet, a method of manufacturing the moisture absorbent sheet and an organic EL display capable of filling a desired amount of moisture absorbent into a sealed space formed by a seal cap and a transparent insulating substrate with an organic EL lamination body certainly and capable of carrying out a filling operation of the moisture absorbent without a trouble, easily and speedily.

Also, it is a second object of the present invention to provide a moisture absorbent sheet, a method of manufacturing the moisture absorbent sheet and an organic EL display capable of making the organic EL display thin and small as a whole.

According to a first aspect of the present invention, there is provided a particle holding sheet for holding a plurality of particles in such a manner that the plurality of particles is held by a support of a sheet-type,

wherein the support has a plurality of spaces connecting to an outside at least at a face of the support and at least a part of the particles is held in one of the spaces.

In the foregoing, a preferable mode is one wherein a gas permeable sheet for allowing air pass and for not allowing the particles pass is fixed to a face of the support and an adhesive layer is arranged on another face of the support.

Also, a preferable mode is one wherein the support is made of woven fabric or unwoven fabric.

Also, a preferable mode is one wherein the support is made of foam materials.

Also, a preferable mode is one wherein the particles are moisture absorbent.

Also, a preferable mode is one wherein the support is made of water-absorbing polymeric materials.

Also, a preferable mode is one wherein the moisture absorbent absorbs moisture physically and/or chemically.

Also, a preferable mode is one wherein the moisture absorbent is made of at least any one of calcium oxide, barium oxide, magnesium oxide, aluminum oxide, and phosphorus oxide.

Furthermore, a preferable mode is one wherein the moisture absorbent is made of at least any one of zeolite, silica gel, and activated carbon.

According to a second aspect of the present invention, there is provided a method of manufacturing a particle holding sheet for holding particles in such a manner that said particles are held by a support of a sheet-type, the method including:

a step of putting the particles into a rotation body which is hollow;

a step of arranging the support inside of a side wall portion of the rotation body;

a step of causing the rotation body to rotate at a predetermined rotation speed for a predetermined time around a rotation axis of the rotation body; and

a step of causing the particles to collide with the support by using a centrifugal force to hold a predetermined amount of the particles by the support.

In the foregoing, a preferable mode is one wherein the support has a plurality of spaces connecting to an outside at least at a face of the support, the support being arranged inside of a side wall portion of the rotation body so that the plurality of spaces are positioned at a central side of the rotation body.

According to a third aspect of the present invention, there is provided a method of manufacturing a particle holding sheet for holding particle by using a support of a sheet-type, the method including:

a step of putting the particles into a rotation body of which a side wall portion has a plurality of small apertures or is made of a mesh member and which is hollow;

a step of arranging the support outside of the side wall portion of the rotation body;

a step of causing the rotation body to rotate at a predetermined rotation speed for a predetermined time around a rotation axis of the rotation body; and

a step of diffusing the particles out of the rotation body by a centrifugal force to cause the support to hold a predetermined amount of the particles.

In the foregoing, a preferable mode is one wherein the support has a plurality of spaces connecting to an outside at least at a face of the support, the support is fixed to a support fitting member and is arranged outside of the side wall portion of the rotation body so that the plurality of spaces are positioned at a central side of the rotation body, and the support fitting member to which the support is fixed is rotated at the predetermined rotation speed for the predetermined time around the rotation axis of the rotation body in a direction same or reverse to a rotation direction of the rotation body.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a particle holding sheet for holding particles such that the particles are held by a support of a sheet-type, the method including:

a step of scattering the particles on the support having a space connecting to an outside at least at a face of the support; and

a step of pressing the particles together with the support by using a press tool to cause the support to hold a predetermined amount of the particles.

In the foregoing, a preferable mode is one wherein the press tool is a pair of rollers, the particles are scattered over the support and are inserted between the pair of rollers to be pressed whereby the particles are held by the support.

Also, a preferable mode is one wherein the particles are moisture absorbent.

According to a fifth aspect of the present invention, there is provided an organic EL display provided with a particle holding sheet for holding a plurality of particles in such a manner that the plurality of particles is held by a support of a sheet-type,

wherein the support has a plurality of spaces connecting to an outside at least at a face of the support and at least a part of the particles is held in one of the spaces.

With the above configurations, since particles are embedded and held by the support having spaces by the centrifugal force, it is possible to fill the support with a desired amount of the moisture absorbent certainly and accurately by adjusting the rotation speed of the rotation body, the effluence time of the moisture absorbent or a like.

Also, by scattering the particles on the support and by pressing with the press tool together with the support, the particles are embedded and held by the support, and therefore, it is possible to embed the plurality of the particles in the spaces of the support speedily.

Further, when the organic EL display is manufactured, the particle holding sheet for holding the moisture absorbent as the particles is put into the seal cap together with the organic EL lamination body, and a like, and therefore, it is possible to enclose a predetermined amount of the moisture absorbent certainly and accurately and it is possible to enclose the moisture absorbent easily and speedily without troubles. It is also possible to reduce a number of steps required to manufacture the organic EL display.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Best modes for carrying out the present invention will be described in further detail using embodiments with reference to the accompanying drawings.

FIRST EMBODIMENT

FIG. 1is a sectional view showing a schematic structure of an organic EL display according to a first embodiment of the present invention,FIG. 2is a view showing a structure of an essential part of a moisture absorbent sheet of the organic EL display,FIG. 3Ais a sectional view showing the essential part of the moisture absorbent sheet along a line A—A inFIG. 2andFIG. 3Bis a sectional view along a line B—B inFIG. 2,FIG. 4is a sectional view showing a structure of a moisture absorbent filling apparatus when the moisture absorbent sheet is manufactured,FIG. 5is a sectional view along a line C—C inFIG. 4,FIG. 6is a view showing a structure of a sheet support portion of the moisture absorbent filling apparatus,FIG. 7andFIG. 8are explanatory views for explaining a method of manufacturing the moisture absorbent sheet, andFIGS. 9A,9B, and9C are process views for explaining the method of manufacturing the moisture absorbent sheet.FIGS. 10A,10B, and10C are process views for explaining a method of manufacturing the organic EL display,FIG. 11is an explanatory view for explaining a method of manufacturing the organic EL display andFIGS. 12A and 12Bare process views for explaining the method of manufacturing the organic EL display.

An organic EL display1, as shown inFIG. 1, is provided with a transparent insulating substrate2such as a glass substrate, an anode layer3, an organic EL lamination body4including a luminescent layer, a cathode layer5, a seal cap6for storing the organic EL lamination body4and a like in a sealed space1A formed with the transparent insulating substrate2and a moisture absorbent sheet (particle holding sheet)7.

The anode layer3is formed in stripes on the transparent insulating substrate2and is made of transparent material such as ITO (indium tin oxide).

The organic EL lamination body4, as shown inFIG. 1, includes a hole injection-transport layer8, a luminescent layer9and an electron injection-transport layer11which are laminated in order.

The hole injection-transport layer8has functions for making injection of holes from the anode layer3easy, for transporting holes to the luminescent layer9stably and for blocking electrons coming from the side of the electron injection-transport layer11and is made of TPD: N,N′-diphenyl-N,N′-di(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine or alike.

The luminescent layer9has functions of generating excitons by recombining the holes injected from the anode layer3with the electrons injected from the cathode layer5and of emitting a light in transition process, and is made up of such as Alq3: tris (8-hydroxyquinolinol) Aluminum or a like.

The electron injection-transport layer11has functions of making injection of electrons from the cathode layer5easy, for transporting electrons to the luminescent layer9stably and for blocking holes coming from the side of the hole injection-transport layer8is made up of such as 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole or a like.

The cathode layer5is formed in stripes so as to be orthogonal to the anode layer3and is made of metal having a low work function such as aluminum.

Areas between the anode layer3and the cathode layer5which are orthogonal to each other in the organic EL lamination body4are used as organic EL pixels (not shown) to be luminescent display units, and the organic EL pixels are arranged in a matrix.

The seal cap6, as shown inFIG. 1, is formed in a box-shaped cap having a predetermined depth (such as approximately 0.4 mm) of metal material such as stainless steel, glass or a like and is put on the transparent insulating substrate2to cover the anode layer3, the organic EL lamination body4, and the cathode layer5via a seal resin12of an ultraviolet-curable type.

The moisture absorbent sheet7is fixed to an opposed surface6aopposite to the cathode layer5in the seal cap6. The moisture absorbent sheet7, as shown inFIG. 2,FIG. 3AandFIG. 3B, has a structure in which a particle-like moisture absorbent13is held by a space15H of a sheet-type support15by being embedded in the space15H and in which a gas permeable sheet17is fixed to the sheet-type support15at a side opposite to the organic EL lamination body4via an adhesive layer16. The sheet-type support15is fixed to the opposed surface6aof the seal cap6via adhesive layer18while holding the moisture absorbent13.

The sheet-type support15, as shown inFIG. 2,FIG. 3AandFIG. 3B, is a plain woven fabric in which a warp15aand a weft15bmade of fluorine polymeric material such as PCTFE (polychlorotrifluoroethylene) or PTFE (polytetrafluoroethylene) are woven together and which has a thickness of approximately 20 μm or a like.

In this embodiment, the warp15aand the weft15b, each of which having a gauge of approximately 10 μm or less, are used. Also, the space15H has a vertical dimension of approximately 10 μm along the warp15aand a horizontal dimension of approximately 10 μm along the weft15b.

The moisture absorbent13is made of particle calcium oxide (CaO) or a like having particle sizes of 2 μm to 20 μm (a mean particle size is 10 μm) as an example. When the calcium oxide absorbs moisture (H2O) in the sealed space1A, the calcium oxide reacts with the moisture to generate calcium hydroxide (Ca(OH)2) and dehumidification is carried out. With this arrangement, deterioration caused by the moisture in the organic EL lamination body4and a like is prevented.

Particles do not pass through the gas permeable sheet17, while water molecules (vapor) pass easily through the gas permeable sheet17. The gas permeable sheet17is electrically-insulative and covers the sheet-type support15to prevent the moisture absorbent13from dropping. Air including the moisture passes through the gas permeable sheet17.

The moisture absorbent sheet7according to this embodiment is made by a moisture absorbent filling apparatus21for filling the sheet-type support15with the moisture absorbent13. The moisture absorbent filling apparatus21will now be explained.

The moisture absorbent filling apparatus21, as shown inFIG. 4andFIG. 5, is provided with an outer cylindrical portion (as a rotation body and as a support fitting member)23and an inner cylindrical portion (as a rotation body)24fixed to a same shaft22as a rotation axis, an electric motor25for rotating the shaft22and a lid portion26. Only tops of the outer cylindrical portion23and the inner cylindrical portion24are opened. The inner cylindrical portion24is stored in the outer cylindrical portion23. When operating by using the electric motor25, the opened tops of the outer cylindrical portion23and the inner cylindrical portion24are covered by the lid portion26.

As shownFIG. 4toFIG. 6, an approximately U-shaped sheet fitting portion27is fixed to an inner wall face23aof the outer cylindrical portion23to form grooves27mfor accepting three peripheral portions of the sheet-type support15with the inner wall face23aexcept the top portion, because the sheet-type support15is inserted from the top.

The sheet fitting portion27includes a mounted portion27afor mounting the sheet-type support15and side control portions27b,27bfor preventing displacement of the sheet-type support15in a rotation direction of the outer cylindrical portion23.

The moisture absorbent13is stored in the inner cylindrical portion24. A plurality of apertures28athrough which the moisture absorbent13can pass are made in a band to form a moisture absorbent effluence portion28. A length “a” of the moisture absorbent effluence portion28along a vertical direction is approximately equal to a length of the sheet-type support15so as to prevent unnecessary moisture absorbent13from effusing to portions to which no sheet-type support15is fixed.

Next, a method of manufacturing the moisture absorbent sheet7will be explained.

First, the sheet-type support15is prepared and, as shown inFIG. 7andFIG. 8, is fixed to the sheet fitting portion27of the moisture absorbent filling apparatus21. Then, the moisture absorbent13is put into the inner cylindrical portion24. During this time, the moisture absorbent13is put into the inner cylindrical portion24until an upper position of a height corresponding to an amount to be held by the sheet-type support15. With this arrangement, the moisture absorbent13is collided with the sheet-type support15evenly.

Then, the electric motor25is started in order to rotate the outer cylindrical portion23and the inner cylindrical portion24at a predetermined rotation speed. The rotation speed set to, for example, several thousand (rpm).

With these processes, the sheet-type support15is pressed and fixed to the inner wall face23aof the outer cylindrical portion23by a centrifugal force. Also, the moisture absorbent13is effused by the centrifugal force, collides with the sheet-type support15and is embedded in the space15H (refer toFIG. 2). After the electric motor25is operated for a predetermined time, a predetermined amount of the moisture absorbent13is embedded and filled in the sheet-type support15.

In this way, as shown inFIG. 9A, the sheet-type support15in which the moisture absorbent13is held by the space15H is obtained and, as shown inFIG. 9B, the adhesive layers16,18are formed on both sides of the sheet-type support15. Then, as shown inFIG. 9C, the gas permeable sheet17is fixed to the sheet-type support15via the adhesive layer16and a removable protecting sheet19is fixed to the sheet-type support15via the adhesive layer18. With this operation, the moisture absorbent sheet7can be obtained.

Next, explanations will be given of a method of manufacturing the organic EL display1using the moisture absorbent sheet7for heremetical sealing.

As shown inFIG. 10A, by a sputtering technique, ITO film is formed on the transparent insulating substrate2such as a glass substrate which is thoroughly washed, and then is patterned by a photography technique to make the anode layer3in stripes.

Then, as shown inFIG. 10B, on the transparent insulating substrate2on which the anode layer3is formed, N,N′-diphenyl-N,N′-di(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine or a like is deposited in a predetermined pattern by a vacuum evaporation technique using a shadow mask to form the hole injection-transport layer8.

Then, by using the vacuum evaporation technique similarly to the hole injection-transport layer8, tris (8-hydroxyquinolinol) Aluminum is deposited to form the luminescent layer9. On the luminescent layer9, 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole is deposited to form the electron injection-transport layer11.

With these processes, the organic EL lamination body4in which the hole injection-transport layer8, the luminescent layer9and electron injection-transport layer11are laminated in order is obtained.

Then, as shown inFIG. 10C, aluminum or like is deposited in a predetermined pattern by the vacuum evaporation technique using a shadow mask to form the cathode layer5in stripes perpendicular to the anode layer3as shown inFIG. 11.

Next, as shown inFIG. 12A, the protecting sheet19has been removed from the moisture absorbent sheet7, and the adhesive layer18has come in contact with the opposed face6ain the seal cap6and the moisture absorbent sheet7is overlaid on the opposed face6a.

Seal resin12of an ultraviolet-curable type is applied to a lower end face of a side wall of the seal cap106in which the moisture absorbent sheet7is overlaid on the opposed face6a.

Then, as shown inFIG. 12B, under an inert gas atmosphere such as nitrogen gas or argon gas, the seal cap6is put on the transparent insulating substrate2and a side wall end face6bof the seal cap6is joined to the transparent insulating substrate2via the uncured seal resin12.

Then, ultraviolet rays UV are irradiated from the side of the transparent insulating substrate2so as to cure the seal resin12. Therefore, the anode layer3, the organic EL lamination body4, and the cathode layer5are sealed by the seal cap6while being filled with nitrogen gas or argon gas. With these processes, the organic EL display1is completed.

As described above, according to this embodiment, the moisture absorbent13is held by the sheet-type support15using the centrifugal force. In this process, by adjusting the rotation speed of the electric motor25, the effluence time of the moisture absorbent13and a like, it is possible to fill the sheet-type support15with a desired amount of the moisture absorbent13certainly and accurately. Also, by the centrifugal force, it is possible to manufacture the moisture absorbent sheet7speedily.

Further, when the organic EL display1is manufactured, the moisture absorbent sheet is put into the seal cap6together with the organic EL lamination body, and therefore, it is possible to enclose a predetermined amount of the moisture absorbent13certainly and accurately.

Furthermore, since the moisture absorbent13is held by the sheet-type support15, in comparison with the conventional technique in which the concave portion of the seal cap is filled with the moisture absorbent, it is possible to use the moisture absorbent effectively using a same amount of moisture absorbent. Therefore, good absorbency can be kept.

For example, in the above-mentioned conventional technique, the moisture absorbent is put into the concave portion formed in a limited area of the seal cap, and all of the moisture absorbent can not be used effectively. On the contrary, since the moisture absorbent13is distributed and put into an area corresponding to a sectional area of the seal cap6, it is possible to use the moisture absorbent13effectively.

Therefore, it is possible to carry out a long lifetime of the organic EL display1.

In other words, as a result of an experiment by the inventor, when no moisture absorbent was put, a lifetime to no luminescence under room temperature was approximately two months. When the moisture absorbent was put into the concave portion of the seal cap in the conventional technique, the lifetime under a same condition was approximately 30,000 hours. Also, the moisture absorbent sheet holding the same amount of the moisture absorbent as in the conventional technique was able to achieve approximately 55,000 hours. In addition, the measured results of the lifetimes were obtained under a condition in that the moisture absorbent of approximately 30 mg was put into the cap of which a sectional area was approximately 50 mm×45 mm.

As described above, according to this embodiment, it was understood that the lifetime was able to be extended to approximately 40 times or more in comparison with a case in that no moisture absorbent was put, and to approximately twice in comparison with the conventional technique in that the moisture absorbent was stored in the concave portion of the seal cap.

Also, it is possible to enclose the moisture absorbent13easily and speedily without troubles. It is possible to reduce a number of steps required to manufacture the organic EL display1.

Also, the moisture absorbent sheet is used when the organic EL display1is manufactured, and therefore it is unnecessary to pay attention to dealing with the moisture absorbent; for example, there is no case in that the moisture absorbent13is dropped wastefully.

Further, since it is unnecessary to form the concave for storing the moisture absorbent13in the seal cap6, the thickness of the seal cap6can be made thin, and therefore, the organic EL display can be made thin and small as a whole.

Furthermore, since a shape of the seal cap6is simple, the seal cap6can be made easily by press molding or a like.

SECOND EMBODIMENT

FIGS. 13A to 13Dare process views for explaining a method of the moisture absorbent sheet13according to a second embodiment of the present invention.

As a main difference between the first embodiment and the second embodiment, instead of a method for embedding a moisture absorbent13into a sheet-type support15using a centrifugal force when the moisture absorbent sheet7is manufactured, the moisture absorbent13is scattered and is pressed by rollers so as to be put into the sheet-type support15.

First, as shown inFIG. 13A, the sheet-type support15is set forward by a pair of rollers, a roller31aand a roller31b, for rotating while respectively pressing an upper face and an lower face of the sheet-type support15.

At a predetermined position, a hopper41is positioned for supplying the moisture absorbent13. As shown inFIG. 13A, the moisture absorbent13is scattered onto the sheet-type support15from an exhaust port41a. A width of the exhaust port41ain a perpendicular direction to a carrying direction of the sheet-type support15is approximately equal to a width of the sheet-type support15, and therefore, the moisture absorbent13is scattered evenly.

Then, as shown inFIG. 13A, the moisture absorbent13is pressed by pairs of rollers31cand31d,rollers31eand31fand rollers31gand31htogether with the sheet-type support15, and therefore, the moisture absorbent13is embedded into the sheet-type support15.

As shown inFIG. 13B, the sheet-type support15is carried to a position of a feeder42for supplying adhesive18aused to form an adhesive layer18and of a container43for applying16aused to form an adhesive layer16by a roller32aand a roller32b.

At this position, the adhesive18ais dropped on the upper face of the sheet-type support15and then is applied by a roller32cevenly to form the adhesive layer18and the adhesive is applied on the lower face of the sheet-type support15by a roller32dto form the adhesive layer16. Then, the sheet-type support15is carried ahead for a next step by a roller32eand a roller32f.

As shown inFIG. 13C, the sheet-type support15is carried to a position for laminating the gas permeable sheet17and the protecting sheet19by a roller33aand a roller33b. The gas permeable sheet17and the protecting sheet19are pressed to the sheet-type support15by a roller33cand a roller33d.

Then, after a drying step or a like, as shown inFIG. 13D, the gas permeable sheet17and the protecting sheet19are respectively laminated via the adhesive layer16and the adhesive layer18. Thereafter, the moisture absorbent sheet7is completed after a cut step of cutting the sheet-type support15at a predetermined size.

As described above, according to this embodiment, by adjusting a supply amount of the moisture absorbent13, a carrying speed of the sheet-type support15and a like, it is possible to fill a desired amount of moisture absorbent13into the sheet-type support15certainly and accurately.

It is thus apparent that the present invention is not limited to the above embodiments but may be changed and modified without departing from the scope and spirit of the invention.

For example, in the above-mentioned embodiments, a plain woven fabric is used as the sheet-type support15, however, the present invention is not limited to the plain woven fabric and a twill woven fabric and a SHUSHI woven fabric having lots of spaces may be used. Also, the present invention is not limited to woven fabrics; and a nonwoven fabric having lots of spaces may be used. Further, a porous foam body such as a polyurethane foam body may be used as the sheet-type support15.

In this way, if only the sheet-type support15has lots of spaces, by embedding the moisture absorbent in the spaces, it is possible to obtain a moisture absorbent sheet. Then, by using the moisture absorbent sheet when an organic EL display is manufactured, it is possible to enclose the moisture absorbent easily, simply, and speedily without problems.

Also, the space15H is not always necessary to penetrate through the sheet-type support15and may be opened at a side opposite to the organic EL lamination body4.

Also, the thickness of the sheet-type support15is not always necessary to be approximately 20 μm and may be 100 μm. A plurality of the sheet-type supports15may be wrapped over and the sheet-type support15may be folded.

Also, the shape of the sheet-type support15may be rectangular, circular, or irregular. It is possible to cut the sheet-type support15into a suitable size and a suitable shape in accordance with a fitting position state of the moisture absorbent sheet. It is also possible to wrap over the moisture absorbent sheet if necessary and to change the shape of the moisture absorbent sheet freely. A plurality of moisture absorbent sheets may be used.

Further as thread textile materials, the present invention is not limited to fluorine polymeric materials, and PET (PolyEthylene Tetraphthalate) or a like may be used.

Also, textile made of water-absorbing polymeric materials or hollow fibrous textiles which are previously dried sufficiently may be used. With these textiles, it is possible to increase an absorbable moisture amount.

Also, the moisture absorbent is not limited to calcium oxide; barium oxide (BaO), magnesium oxide (MgO), aluminum oxide (Al2O3), phosphorus oxide (such as diphosphorus pentoxide (P2O5), or a like may be used. Absorbing the moisture, these oxides react with the moisture and chemical changes occur as well as calcium oxide. Therefore, there is no case in that the moisture effuses even though heated.

Further, zeolite, silica gel, activated carbon or a like which absorbs moisture physically may be used as the moisture absorbent. Also, a deliquescent substance such as calcium chloride (CaCl2) and magnesium chloride (MgCl2) may be used as the moisture absorbent. In this case, the deliquescent substance is made into an aqueous solution, the sheet-type support is soaked in the aqueous solution or the aqueous solution is sprayed onto the sheet-type support, and then the sheet-type support is heated and dried to manufacture the moisture absorbent sheet. It is also possible to mix moisture absorbent for absorbing moisture physically and moisture absorbent for absorbing moisture chemically.

The seal cap6is not limited to metal material such as stainless steel; and transparent glass or a like may be formed into a cap.

The anode layer is not limited to ITO; and tin oxide (SnO2) or a like may be used if only transparent.

In the organic EL lamination body, the hole injection-transport layer is not limited to N,N′-diphenyl-N,N′-di (3-methylphenyl)-1,1′-biphenyl-4,4′-diamine; a hydrazone derivative, a carbazole derivative, a triazole derivative, or a like may be used. The luminescent layer9is not limited to tris (8-hydroxyquinolinol) aluminum; and a phenylanthracene derivative, a tetraallylethene derivative, or a like may be used. The electron injection-transport layer11is not limited to 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole; and a pyridine derivative, a diphenylquinone derivative, or a like may be used.

The hole injection-transport layer may divided into two layers including a hole injection layer and a hole transport layer and the two layers may be laminated. In this case, a compound used in the hole injection layer has low potential. Similarly, the electron injection-transport layer may be divided into two layers including an electron injection layer and an electron transport layer and the two layers may be laminated.

A function of a luminescent layer may be added to the hole injection-transport layer. Also, the organic EL lamination body may include a hole transport layer and a luminescent layer and may include only a luminescent layer.

The cathode layer is not limited to aluminum; and magnesium, aluminum-lithium alloy, or a like may be used.

In the first embodiment, in a moisture absorbent filling apparatus21, an inner cylindrical portion24, and an outer cylindrical portion23are rotated at the same time, however, the inner cylindrical portion24and the outer cylindrical portion23may be rotated at respective rotation speeds or only the inner cylindrical portion24may be rotated. With this arrangement, it is also possible to insert the moisture absorbent into the sheet-type support.

In this case, the inner cylindrical portion24and the outer cylindrical portion23may be rotated reversely. With this arrangement, since it is possible to embed the moisture absorbent into the sheet-type support with a more impact force of collision, large amounts of the moisture absorbent can be held by the sheet-type support.

In the second embodiment, the case in that the moisture absorbent is pressed into the sheet-type support by the pairs of rollers is described. Also, after scattering the moisture absorbent over the sheet-type support evenly, the moisture absorbent may be pressed into the sheet-type support by using a press tool having a press surface which is a plain surface to press the press surface to the tool sheet-type support.

Also, the moisture absorbent may be embedded into spaces of the sheet-type support by supplying the moisture absorbent from one side of the sheet-type support, by keeping a pressure at the other side of the sheet-type under a pressure at the one side (such as atmospheric pressure) and by inhaling the moisture absorbent via the gas permeable sheet.

Also, the moisture absorbent sheet7may be provided with the gas permeable sheet17and the adhesive layer18if necessary, and the gas permeable sheet17and the adhesive layer18may be omitted.

Also, in the embodiment, descriptions are given of the case in that the adhesive layer18is previously provided at a side of the moisture absorbent sheet7and the moisture absorbent sheet7is fixed to the seal cap6, however, the adhesive layer18may be previously provided at the opposed face6aof the seal cap6and the moisture absorbent sheet7may be fixed to the seal cap6. With this arrangement, the protecting sheet19can be omitted.

Also, the moisture absorbent sheet7may be fixed to a side wall surface in addition to the opposed face6ain the seal cap6. Further, the moisture absorbent sheet7may be fixed to only the side wall surface.

In the embodiments, descriptions are given of the case in that the moisture absorbent sheet7is applied to the organic EL display, however, the moisture absorbent sheet7may be applied to an inorganic EL, a solar battery module, and a like and is not limited to the organic EL display.

Furthermore, particles held by the particle holding sheet of the present invention are not limited to the moisture absorbent and may be particles such as magnetic powder, catalyst, and oxygen moisture absorbent.

By using the particle holding sheet for holding particles, it is also possible to solve difficulty when dealing with particles and it is possible to embed particles into a needed position easily and speedily without problems.