JP3992450B2 - Electroluminescence display device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electroluminescence display device configured by joining a plurality of display panels and a method for manufacturing the same.
[0002]
[Prior art]
In recent years, with the diversification of information equipment, there has been an increasing need for flat display elements that consume less power than commonly used CRTs (cathode ray tubes). As one of such flat display elements, an electroluminescence (hereinafter abbreviated as EL) element having features such as high efficiency, thinness, light weight, and low viewing angle dependency has attracted attention. Research and development is active. Such EL elements include an inorganic EL element having a light emitting layer made of an inorganic material and an organic EL element having a light emitting layer made of an organic material.
[0003]
An inorganic EL element is a self-luminous element that generally emits light by exciting a light emission center by applying a high electric field to a light emitting portion and accelerating electrons in the high electric field to collide with the light emission center.
[0004]
On the other hand, the organic EL element injects electrons and holes from the electron injection electrode and the hole injection electrode, respectively, into the light emitting part, recombines the injected electrons and holes at the light emission center, and makes the organic molecule excited. It is a self-luminous element that generates fluorescence when an organic molecule returns from an excited state to a ground state. This organic EL element can change a luminescent color by selecting the fluorescent material which is a luminescent material, and the expectation for the application to display apparatuses, such as multi-color and a full color, is increasing.
[0005]
At present, the above organic EL elements are in the stage of application to small displays such as digital cameras and mobile phones, and it is considered difficult to apply them to medium and large displays such as personal computers and televisions. ing. For example, in the case of an active display, it is difficult to produce a large number of polysilicon TFTs (thin film transistors) over a large area, and even in the case of a passive display, it is difficult to form an organic film uniformly over a large area. .
[0006]
For this reason, there is an attempt to produce a large organic EL display device by combining a plurality of small organic EL panels.
[0007]
[Problems to be solved by the invention]
Usually, when a small panel is simply combined, the joint between the panels is conspicuous and a good display screen cannot be obtained. On the other hand, in a liquid crystal display device, in order to make the joint between small panels inconspicuous, three display dots of R, G, and B are set as one pixel, and the distance between pixels located at adjacent panel ends is black. It has been reported to match the width of the stripe (Sharp Technical Report No. 69, December 1997, p. 81-84). The side on the joining side is cut with a dicing device, and the cut surface is further polished to improve the cutting accuracy.
[0008]
However, such a processing method is specific to a liquid crystal display device in which the panel end is sealed so that the liquid crystal inside does not leak, and the distance from the pixel located at the panel end to the panel end is increased. Therefore, it cannot be applied as it is to an EL display device that does not have such a seal structure. In other words, when water is used to remove heat generated during dicing and polishing, cutting chips (chipping) generated during processing, and abrasives such as cerium oxide, it is removed from the metal due to the influence of moisture entering from the processed surface. The electrode is oxidized, or the electrode is peeled off at the interface with the light emitting layer made of an organic material or an inorganic material, so that the light emitting portion is deteriorated. As a result, a dark spot is generated and the light emitting element does not function.
[0009]
An object of the present invention is to provide an electroluminescence display capable of deteriorating a light emitting portion and making a joint portion of adjacent display panels inconspicuous when a plurality of display panels are joined to form one display device. An apparatus and a method for manufacturing the same are provided.
[0010]
[Means for Solving the Problems and Effects of the Invention]
An electroluminescence display device according to a first invention is an electroluminescence display device in which a plurality of display panels are joined, each of the plurality of display panels including a plurality of light emitting portions formed on one surface of a substrate, The other surfaces of the substrates of the plurality of display panels are bonded to each other on a common base by an adhesive, and the end surfaces of adjacent panels are bonded to each other by an adhesive. Is covered with a mask material.
[0011]
In the electroluminescence display device according to the present invention, a plurality of display panels having a plurality of light emitting portions are bonded on a common base, and the bonding portions on the light emitting portion side of each display panel are covered with a mask material. Yes.
[0012]
In this case, since the joint part on the light emitting part side of each display panel is covered with the mask material, the adhesive used when joining the display panel on the common base oozes out to the light emitting part of each display panel. And the deterioration of the light emitting part due to the moisture of the adhesive can be prevented.
[0013]
One or a plurality of light emitting portions may constitute a pixel, and the mask material may have a width equal to or smaller than an interval between the pixels. In this case, since the mask material has a width equal to or smaller than the interval between the pixels, a plurality of display panels can be bonded without increasing the interval between the pixels at the bonding portion of the display panel. Thereby, the joint of the display panel can be made inconspicuous while keeping the resolution of the video high.
[0014]
The width of the mask material is preferably 300 μm or less. Thereby, the joint of the display panel can be made inconspicuous while keeping the resolution of the video high.
[0015]
The refractive index of the adhesive may be equal to the refractive index of the base. In this case, since the refractive indexes of the adhesive and the base are the same, the joint of the display panel can be made inconspicuous when the display panel is joined.
[0016]
The plurality of light emitting unit side spaces may be sealed by the container so as to cover the plurality of light emitting units of the plurality of display panels. In this case, the plurality of light emitting unit side spaces are sealed by the container so as to cover the plurality of light emitting units of the plurality of display panels. Thereby, the damage to the light emission part by the water | moisture content of resin etc. which generate | occur | produces when resin etc. are used as a sealing layer can be eliminated. In addition, since a sealing layer made of resin or the like is not required, the light emitting portion does not generate stress due to heat generated when the pixel is lit, and the light emitting portion can be prevented from being peeled off. Display is possible.
[0017]
The plurality of light emitting units may be formed of an organic material. In this case, since the plurality of light emitting portions are formed of an organic material that is very weak against moisture, it is particularly effective to adopt the configuration of the above-described electroluminescence display device that prevents the penetration of moisture.
[0018]
A method for manufacturing an electroluminescence display device according to a second invention is a method for manufacturing an electroluminescence display device in which a plurality of display panels are joined, and a plurality of light emitting portions are respectively formed on one surface of a plurality of substrates. A step of forming a plurality of display panels, a step of covering the boundary portions between the end portions of the plurality of display panels with a mask material on the side of the plurality of light emitting portions, and a common substrate on the other surface of the plurality of display panels. And a step of joining the ends of adjacent display panels to each other using an adhesive.
[0019]
In this case, a plurality of display panels are formed by respectively forming a plurality of light emitting portions on one surface of a plurality of substrates, and a boundary portion between the ends of the plurality of display panels is formed by a mask material on the plurality of light emitting portion sides. The other surfaces of the substrates of the plurality of display panels that are covered are bonded to a common base by an adhesive, and the ends of adjacent display panels are bonded to each other by an adhesive.
[0020]
Thereby, since the adhesive for joining the display panel on the common base is used after the joint part on the light emitting part side of each display panel is covered with the mask material, the adhesive is applied to the light emitting part of each display panel. Exudation can be prevented, and deterioration of the light emitting portion due to moisture in the adhesive can be prevented.
[0021]
Before forming a plurality of display panels, a step of processing an end portion of each substrate may be further included. Thereby, it is possible to prevent damage to a plurality of light emitting portions due to chipping generated when processing the end portion of the substrate and moisture used for removing the abrasive.
[0022]
You may further provide the step which seals the space of the several light emission part side with a container so that the several light emission part of a several display panel may be covered. In this case, since a sealing layer such as a resin is not used as a protective layer for protecting a plurality of light emitting portions of a plurality of display panels from moisture or the like, a resin generated when a resin or the like is used as a sealing layer. Damage to the light emitting part due to moisture can be eliminated. In addition, since a sealing layer made of resin or the like is not required, the light emitting portion does not generate stress due to heat generated when the pixel is lit, and the light emitting portion can be prevented from being peeled off. Display is possible.
[0023]
Note that the step of sealing the spaces on the side of the plurality of light emitting units with the container may be before or after the step of joining the plurality of display panels on the common base.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an organic electroluminescence (hereinafter abbreviated as EL) display device will be described as an example of the electroluminescence display device according to the present invention. The present invention is particularly useful for an organic EL display device using an organic material that is inferior in heat resistance and moisture resistance as a light emitting portion, but can also be applied to an inorganic EL display device having a similar structure. The present invention can be applied to both display types and passive display devices.
[0025]
FIG. 1 is a schematic plan view showing a configuration of an organic EL display device according to an embodiment of the present invention. The organic EL display device 1 shown in FIG. 1 includes four small panels 2a to 2d. Each of the small panels 2a to 2d includes a plurality of light emitting portions 3a to 3d, a plurality of scanning pixel electrodes 5a to 5d, a plurality of signal pixel electrodes 6a to 6d, scanning pixel electrode driving circuits 7a to 7d, and a signal pixel electrode driving circuit. 8a to 8d and a mask 4 are provided.
[0026]
The scanning pixel electrode driving circuits 7a to 7d are arranged on one side of the small panels 2a to 2d, and the signal pixel electrode driving circuits 8a to 8d are arranged on the other side of the small panels 2a to 2d. The scanning pixel electrode driving circuits 7a to 7d and the signal pixel electrode driving circuits 8a to 8d are driven to the scanning pixel electrodes 5a to 5d and the signal pixel electrodes 6a to 6d forming the light emitting portions 3a to 3d corresponding to the pixels to be displayed. Output a signal. Accordingly, the light emitting units 3a to 3d emit light, and display driving is possible only by the small panels 2a to 2d.
[0027]
As shown in FIG. 1, the organic EL display device 1 includes four small panels 2 a to 2 d with an adhesive so that each of the scanning pixel electrodes 5 a to 5 d and the signal pixel electrodes 6 a to 6 d are continuously arranged. It is bonded and enlarged to a desired size. Further, a mask 4 is provided at the boundary between the small panels 2a to 2d so that the adhesive does not ooze out on the image display side. In this case, one screen can be displayed as one large panel by driving the electrodes 5a to 5d and 6a to 6d in synchronization with the upper, lower, left and right drive circuits 7a to 7d and 8a to 8d. .
[0028]
For example, when manufacturing a 10-inch monochrome display device of VGA (Video Graphics Array) specifications of 640 dots wide × 480 dots high, a small size of 5 inches with 320 pixels wide × 240 dots high and a pixel pitch of about 300 μm. Four panels 2a to 2d may be bonded together. In a full-color display device, one pixel is formed with three types of light emitting units of R (Red), G (Green), and B (Blue) as one unit.
[0029]
FIG. 2 is a schematic cross-sectional view of the organic EL display device of FIG.
As shown in FIG. 2, it is composed of glass substrates 9a and 9b on which scanning pixel electrodes 5a and 5b of FIG. 1 made of ITO or the like are formed and light emitting portions 3a and 3b provided on the glass substrates 9a and 9b, respectively. Small panels 2a and 2b are attached to a reinforcing glass substrate 10 with an adhesive 11. Although only two small panels 2a and 2b are shown in FIG. 2, the four small panels 2a, 2b, 2c and 2d shown in FIG.
[0030]
A mask 4 is provided on the boundary line between the small panels 2a and 2b. Similarly, the mask 4 is also provided on the boundary lines of the small panels 2a and 2c, the boundary lines of the small panels 2b and 2c, and the boundary lines of the small panels 2c and 2d. Furthermore, it is sealed with a can (CAN) 12 so as to cover the entire small panels 2a, 2b, 2c, 2d.
[0031]
FIG. 3 is a schematic view of a manufacturing process of the organic EL display device of FIG.
First, as shown in FIG. 3A, the end portion 14 of the glass substrate 9a on which the scanning pixel electrode 5a such as ITO is formed is cut to a desired pixel pitch with a blade 13 of a dicing device or a scribe device. Then, the cut end face is polished and polished smoothly so that high-precision bonding can be performed.
[0032]
Then, as shown in FIG. 3B, a hole injection layer is formed on the glass substrate 9a as the light emitting portion 3a, and a signal pixel electrode 6a functioning as a hole transport layer, a light emitting layer, and an electron injection electrode is sequentially formed thereon. . Here, a triphenylamine dielectric having a thickness of 1000 mm is used as the hole injection layer, a diamine dielectric having a thickness of 200 mm is used as the hole transport layer, and a 200 mm thickness is used as the light emitting layer. An aluminum quinolinol complex doped with quinacridone or the like is used, and the signal pixel electrode 6a is made of 3000 mm thick magnesium indium (MgIn). In this way, the small panel 2a is manufactured. Similarly, small panels 2b, 2c and 2d are also produced.
[0033]
Next, as shown in FIG. 3C, a mask 4 is formed at the joints on the light emitting parts 3a, 3b side of the adjacent small panels 2a, 2b. As a method for forming the mask 4, an ultraviolet curable resin (AVR200 manufactured by ThreeBond) is applied with a width of 300 μm using a dispenser, and then cured by irradiation with ultraviolet rays. This method has a simple process. Other mask 4 forming methods include application of visible light curable resin by a dispenser, vacuum deposition using a metal mask, formation of an inorganic material by RF sputtering, formation of an inorganic material by laser CVD, and epoxy resin by screen printing. There is application of. The width of the mask 4 is desirably 300 μm or less in consideration of the pixel pitch. In the same manner, the mask 4 is also formed at the junction between the small panels 2a and 2c, the junction between the small panels 2b and 2c, and the junction between the small panels 2a and 2d.
[0034]
Thereafter, as shown in FIG. 3D, the small panels 2 a and 2 b are bonded to the reinforcing glass substrate 10 using an adhesive 11. As the adhesive 11, an adhesive having a refractive index close to the refractive index Nd of the glass used for the glass substrates 9 a and 9 b and the glass used for the reinforcing glass substrate 10 is used in order to reduce optical discomfort. The refractive index Nd of the glass used is about 1.5 to 1.6. For example, when a Corning 1737 substrate (Nd = 1.52) is used as the glass substrate 10, 9a, 9b, as the adhesive 11, Three bond AVR200 (Nd = 1.56) and Nagase Ciba XNR5623 (Nd = 1.57), which are ultraviolet curable resins, are used. Similarly, the small panels 2c and 2d are attached on the same glass substrate.
[0035]
In the step of FIG. 3D, when the mask 4 is formed on the joint surface on the light emitting portion 3a, 3b side of the adjacent small panels 2a, 2b, the adhesive glass 11 is bonded to the glass substrate 10 for reinforcement. In addition, it is possible to prevent the adhesive 11 from protruding from the joint portion toward the light emitting portions 3a and 3b.
[0036]
Finally, as shown in FIG. 3 (e), the entire light emitting portions 3a, 3b, 3c, 3d side of the small panels 2a, 2b, 2c, 2d are sealed with a glass or metal can 12.
[0037]
The steps of FIGS. 3C to 3E are performed in a glove box filled with a nitrogen gas atmosphere. For this reason, the space between the small panels 2a, 2b, 2c, 2d of the produced organic EL display device and the can 12 is filled with nitrogen gas.
[0038]
In this way, the organic EL display device 1 shown in FIG. 1 is produced. In addition, you may interchange the process of FIG.3 (d), and the process of FIG.3 (e).
[0039]
Further, in the present embodiment, the 2 × 2 organic EL display device 1 is described by using the four small panels 2a to 2d. However, the number of the small panels attached is not particularly limited to four, but one Other numbers may be used as long as the display device can be configured. For example, this is also effective when small panels are arranged in a line or arranged in a matrix such as 3 × 3, 2 × 3.
[0040]
In the production of the organic EL display device 1 according to the present invention, the end faces of the joint portions of the small panels 2a to 2d are processed before the light emitting portions 3a to 3d are formed as described above, thereby joining the small panels 2a to 2d. The problem that the light emitting portions 3a to 3d are peeled off due to stress when the portion is cut and polished is solved. Further, the signal pixel electrodes 6a to 6d are not oxidized even when processed while flowing water in order to remove the heat generated during cutting or polishing, or cutting pieces and abrasives, and at the interface with the organic material. No peeling occurs.
[0041]
Further, since the adhesive 11 does not protrude to the light emitting parts 3a to 3d side due to the masking effect by the mask 4, it is possible to prevent the moisture of the adhesive 11 from penetrating into the light emitting parts 3a to 3d side. By sealing the can, it is possible to prevent stress from being generated in the sealing layer due to heat generated when the pixel is lit, and damage to the light emitting portions 3a to 3d.
[0042]
【Example】
Here, organic EL display devices of Examples and Comparative Examples were manufactured and characteristics were evaluated. The organic EL display device of the example was manufactured by the manufacturing method shown in FIGS. The organic EL display device of the comparative example was manufactured by the manufacturing method shown below.
[0043]
FIG. 4 is a schematic cross-sectional view showing a manufacturing process of an organic EL display device of a comparative example. Although FIG. 4 shows the small panels 20a and 20b, the same applies to the other two small panels.
[0044]
As shown to Fig.4 (a), the several light emission part 30a and the sealing layer 40a were formed on the glass substrate 90a. Then, the edge part 140 shown to Fig.4 (a) was cut | disconnected to the desired pixel pitch with the blade 130 of the dicing apparatus or the scribe apparatus, and the joining surface was formed. Similarly, the small panel 20b and the other two small panels are manufactured.
[0045]
The light emitting unit 30a is formed on the light emitting layer, the hole injection layer formed on the scanning pixel electrode, the hole transport layer formed on the hole injection layer, the light emitting layer formed on the hole transport layer, and It consists of an electron transport layer and a signal pixel electrode formed on the electron transport layer. The material and configuration of each layer are the same as in the examples.
[0046]
Each of the above layers was formed using a vacuum evaporation method using a resistance heating boat with a degree of vacuum of 10 ⁻⁴ Pa or less. The light emitting units 30a and 30b thus formed emitted light with a luminance of 100 to 300 cd / m ² by applying a driving voltage of 5 to 10V.
[0047]
Thereafter, the joining surface of the small panel 20a was smoothly polished and finished with a high-precision abrasive so that high-precision bonding was possible. Cerium oxide was used as the high-precision abrasive. In this case, cutting and polishing were performed while flowing water in order to suppress heat generation and remove cutting fragments and abrasives. The end portion of the small panel 20b and the other two small panels were similarly cut and polished.
[0048]
Further, as shown in FIGS. 4B and 4C, the bonding portions of the small panels 20a and 20b are bonded using the adhesive 110, and the entire glass substrates 90a and 90b are reinforced glass substrates. 100. Similarly, the other two small panels were bonded to the same glass substrate 100 for reinforcement. FIG.4 (c) is an enlarged view of the A section shown in FIG.4 (b). As the adhesive 110, an ultraviolet curable adhesive or a polymer adhesive having optical characteristics close to the refractive index of glass in the visible light wavelength region was used.
[0049]
In the organic EL display device in the comparative example, the initial luminance is greatly lower than the above-mentioned value of 100 to 300 cd / m ² in the pixels near the bonded surface due to heat damage to the organic material due to heat generated during dicing or polishing. became. On the other hand, in the example, since the bonding portion of the small panel is processed before the light emitting portion is formed, the initial luminance is not lowered.
[0050]
Further, in the comparative example, since water was used to remove heat generated during dicing and polishing, cutting pieces (chipping) generated during processing, and abrasives such as cerium oxide, moisture entering from the processing surface As a result of this, the electrode made of metal is oxidized, or the electrode is peeled off at the interface with the light emitting layer made of an organic material or an inorganic material, so that the light emitting portion is deteriorated. As a result, a dark spot was generated, and the device did not function as a light emitting element. On the other hand, in the embodiment, by providing a mask at the light-emitting part side joint of a plurality of small panels, it was possible to prevent the moisture of the adhesive itself from penetrating the light-emitting part side. The part did not deteriorate during processing and polishing.
[0051]
Furthermore, in the comparative example, stress was generated around the light emitting portion due to heat generation during light emission, and the sealing layer was deformed by this stress, and the light emitting portion was damaged. On the other hand, in the examples, since the light emitting portion side was sealed with a can, the generation of stress due to heat generation was suppressed, and since no sealing layer was present, damage to the light emitting portion was also suppressed. For this reason, the deterioration of the light emitting part after emitting light for a certain time was very small as compared with the comparative example.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a configuration of an organic EL display device according to an embodiment of the present invention.
2 is a cross-sectional view showing a configuration of the organic EL display device of FIG.
FIG. 3 is a schematic diagram illustrating a manufacturing process of the organic EL display device of FIG. 1;
FIG. 4 is a schematic cross-sectional view illustrating a manufacturing process of an organic EL display device of a comparative example.
[Explanation of symbols]
2a to 2d Small panels 3a to 3d Light emitting part 4 Mask 10 Reinforcing glass substrate 11 Adhesive 12 Can

Claims (9)

An electroluminescence display device in which a plurality of display panels are joined,
Each of the plurality of display panels includes a plurality of light emitting portions formed on one surface of a substrate, and the other surfaces of the substrates of the plurality of display panels are adjacent to each other on a common base by an adhesive. An electroluminescence display device, wherein end faces of the panels are bonded to each other by an adhesive, and a bonding portion between the adjacent display panels is covered with a mask material on the plurality of light emitting portion sides.   The electroluminescence display device according to claim 1, wherein one or a plurality of light emitting units constitute pixels, and the mask material has a width equal to or smaller than an interval between the pixels.   3. The electroluminescence display device according to claim 2, wherein the mask material has a width of 300 [mu] m or less.   The electroluminescent display device according to claim 1, wherein a refractive index of the adhesive is equal to a refractive index of the base.   5. The electroluminescence display device according to claim 1, wherein a space on the side of the plurality of light emitting units is sealed by a container so as to cover the plurality of light emitting units of the plurality of display panels. .   The electroluminescent display device according to claim 1, wherein the plurality of light emitting portions are formed of an organic material. A method of manufacturing an electroluminescence display device in which a plurality of display panels are joined,
Forming a plurality of display panels by respectively forming a plurality of light emitting portions on one surface of a plurality of substrates;
Covering the boundary between the end portions of the plurality of display panels with a mask material on the side of the plurality of light emitting portions; and
Electro bonding, comprising bonding the other surfaces of the substrates of the plurality of display panels to a common base with an adhesive and bonding the ends of adjacent display panels to each other with an adhesive. Manufacturing method of luminescence display device. 8. The method of manufacturing an electroluminescence display device according to claim 7 , further comprising a step of processing an end portion of each substrate before forming the plurality of display panels. The electroluminescent display device according to claim 7 , further comprising a step of sealing a space on the side of the plurality of light emitting units with a container so as to cover the plurality of light emitting units of the plurality of display panels. Manufacturing method.

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