JP5214174B2 - Method for manufacturing organic electroluminescence device - Google Patents

Description

  The present invention relates to a method of manufacturing an organic EL device (organic electroluminescence device) having an organic EL (Electro Luminescent) element.

  As a light source for a thin and light display, OLED (Organic Light Emitting Diode), that is, an organic EL element has been attracting attention. The organic EL element has a structure in which at least one organic thin film formed of an organic material is sandwiched between a pixel electrode and a counter electrode. In a coating method, which is one of the methods for forming an organic thin film, an organic solution containing an organic thin film material (for example, a functional polymer) and an organic solvent, that is, an ink is applied onto a substrate and dried.

  In general, the drying speed of ink tends to be higher at the end than at the center of the substrate. The cause is that the concentration of the organic solvent in the atmosphere near the edge of the substrate is lower than the concentration of the organic solvent in the atmosphere near the center of the substrate. When such drying unevenness occurs, unevenness occurs in the film thickness of the formed organic thin film. This film thickness unevenness causes brightness unevenness and light emission color unevenness.

Therefore, an organic EL device has been proposed in which the organic thin film at the center (light emitting region) of the substrate is used for light emission, while the organic thin film at the end of the substrate (a strip-like dummy region surrounding the light emitting region) is not used for light emission ( Patent Document 1). According to this organic EL device, since the organic thin film in the dummy region, that is, the organic thin film at the edge of the substrate is not used for light emission, it is possible to reduce luminance unevenness and light emission color unevenness caused by drying unevenness.
JP 2002-252083 A

  However, in the organic EL device described in Patent Document 1, it is necessary to secure a strip-shaped space having a width of several millimeters serving as a dummy region on the substrate on which the organic EL element is formed. This becomes an obstructive factor for narrowing the frame of the organic EL device (particularly, narrowing the frame of a display of a portable device such as a mobile phone or a portable music player).

  Therefore, the present invention provides a method for manufacturing an organic EL device that can reduce luminance unevenness and light emission color unevenness due to drying unevenness without inhibiting narrowing of the frame.

The present invention includes a substrate and a manufacturing method of an organic electroluminescent device having an organic thin film formed on the substrate has a recess in which the upper is open, said at stage detachable container is attached container A step of placing the substrate on a portion to which no ink is attached, a step of arranging an ink containing the organic thin film material and an organic solvent or the organic solvent in the concave portion of the container, and arranging the ink or the organic solvent. of the substrate that is loaded on the stage that is, the region for forming the organic thin film, it has a a step of applying the ink, the bottom of the recess, the pixel electrode and the counter electrode sandwiching the organic thin film Among them, the pixel electrode is formed and is located above the upper surface of a layer provided on the substrate .
Further, the present invention provides a method for manufacturing an organic electroluminescence device having a substrate and an organic thin film formed on the substrate, wherein the organic thin film is disposed on a portion of the stage on which the substrate is placed so as not to overlap the substrate. In a region for forming the organic thin film on the substrate placed on the stage on which the ink or the organic solvent is disposed, and the first step of disposing the ink containing the material and the organic solvent or the organic solvent. And a second step of applying the ink. A manufacturing method (first manufacturing method) is provided. A “stage” is a stage on which a substrate is placed. According to the first manufacturing method, in the ink drying process, the organic solvent is volatilized from the ink applied on the substrate, and the liquid disposed around the substrate (on the portion of the stage that does not overlap the substrate). Since the organic solvent is volatilized from (ink or organic solvent), the concentration of the organic solvent in the atmosphere near the edge of the substrate is close to the concentration of the organic solvent in the atmosphere near the center of the substrate, and the film thickness unevenness of the organic thin film Is reduced. Further, according to the first manufacturing method, it is not necessary to secure a space as a dummy region on the substrate. Therefore, according to the first manufacturing method, it is possible to reduce luminance unevenness and light emission color unevenness due to drying unevenness without inhibiting narrowing of the frame of the organic EL device.

  In the first manufacturing method, a lower end of the ink or the organic solvent disposed on a portion of the stage that does not overlap the substrate is positioned above an upper surface of the substrate placed on the stage. You may make it (2nd manufacturing method). According to the second manufacturing method, the lower end of the liquid disposed in the periphery of the substrate is lower than the upper surface of the substrate placed on the stage, and the liquid disposed in the periphery of the substrate. Since it becomes easy to bring the volatile surface closer to the volatile surface of the ink applied to the edge of the substrate, the amount of dummy organic solvent can be reduced.

  In the first or second manufacturing method, the stage is formed with a concave portion opened upward at a position that does not overlap the substrate, and in the first step, the ink or the organic solvent is put into the concave portion. Alternatively, a container having a recess is attached to the stage at a position that does not overlap the substrate so that the recess opens upward. In the first step, the ink or The organic solvent may be added. According to each of these forms, the amount of the liquid can be adjusted while maintaining the positional relationship between the ink applied on the substrate and the liquid disposed around the substrate. In addition, according to the latter form, by removing the container, one stage can be used for manufacturing a plurality of types of organic EL devices having different substrate sizes.

  In the first manufacturing method, the upper surface of the stage may be flat, and the ink or the organic solvent may be disposed in contact with the upper surface of the stage in the first step. This form has the advantage that the existing stage can be used as it is.

  Hereinafter, various embodiments according to the present invention will be described with reference to the accompanying drawings. The organic EL device according to each embodiment is an organic EL device having a substrate and an organic thin film formed on the substrate. Specifically, a structure in which one organic thin film is sandwiched between a pixel electrode and a counter electrode. This is a light emitting device (display device) in which the pixels (organic EL elements) are arranged in a matrix. In addition, the organic EL device according to each embodiment forms an organic thin film by ejecting ink containing an organic solvent and a polymer or a low molecule, which is a material of the organic thin film (organic electroluminescent material), from an inkjet head. Manufactured by the inkjet method. In the drawings, the ratio of dimensions of each part is appropriately different from the actual one.

<First Embodiment>
FIGS. 1-7 is a figure for demonstrating the manufacturing method of the organic electroluminescent apparatus based on the 1st Embodiment of this invention. 1 is a sectional view showing the first step, FIG. 2 is a sectional view showing the next step of FIG. 1, FIG. 3 is a plan view showing the step of FIG. 2, and FIG. 4 is the next step of FIGS. FIG. 5 is a sectional view showing the next step of FIG. 4, FIG. 6 is a sectional view showing the next step of FIG. 5, and FIG. 7 is a sectional view showing the result of the step of FIG.

  In the manufacturing method according to the present embodiment, first, the intermediate body 5 in FIG. 1 is manufactured. Specifically, the layer 20 is formed on the substrate 10, and the pixel electrode 30 serving as an anode or a cathode of the organic EL element is patterned on the layer 20, thereby forming the plurality of pixel electrodes 30 on the layer 20. In addition, the base layer 40 is formed of an inorganic insulator such as silicon oxide or silicon nitride so as to surround the pixel opening (the central region of the upper surface of the pixel electrode 30), and the pixel opening is surrounded on the base layer 40. The partition wall (bank) 50 is formed of an insulating resin material such as acrylic, epoxy, or polyimide.

  The material of the substrate 10 is, for example, glass, ceramic, or metal, and can be appropriately selected according to the emission type (bottom emission type, top emission type, or dual emission type) of the organic EL device to be manufactured. The layer 20 includes a plurality of TFTs (thin film transistors) 21 for supplying current to the organic EL elements to emit light, conductors 22 that electrically connect the TFTs 21 and the pixel electrodes 30, power supply lines (not shown), and the like. An inorganic insulator (for example, silicon oxide or silicon nitride) covering the electrical circuit element is included. Further, the pixel electrode 30, the base layer 40, and the partition wall 50 define a region R in which an organic thin film is formed.

Next, as shown in FIG. 1, the exposed surface of the partition wall 50 is subjected to a liquid repellency treatment. Specifically, a plasma process (CF ₄ plasma process) using tetrafluoromethane as a process gas is performed in an air atmosphere. Thereby, a fluorine group is introduced into the exposed surface of the partition wall 50 to impart liquid repellency.

  Next, as shown in FIGS. 2 and 3, the intermediate body 5 is placed on the drawing stage 70. The drawing stage 70 is a stage on which the intermediate body 5 (substrate 10) is placed, and a central portion 71 on the upper surface thereof is flat. When the intermediate body 5 is placed on the drawing stage 70, the entire lower surface of the substrate 10 is brought into contact with the central portion 71. Further, a groove (concave portion) 72 opened upward is formed in the drawing stage 70 so as to surround the central region 71. At the time of the above placement, the substrate 10 is prevented from overlapping the groove 72. In other words, the groove 72 is formed in the drawing stage 70 at a position that does not overlap the substrate 10.

  Next, as shown in FIG. 4, an organic solvent is placed on the portion of the stage 70 that does not overlap the substrate 10 (first step). That is, an organic solvent is disposed around the substrate 10. Specifically, about 10 microliters of organic solvent is placed in the groove 72. This insertion method is arbitrary, and for example, it may be dropped with a dropper or may be ejected from an inkjet head. Hereinafter, the organic solvent put in the groove 72 is referred to as “dummy”.

  Next, as shown in FIG. 5, ink is applied to all regions R on the substrate 10 placed on the drawing stage 70 on which the dummy is arranged (second step). Specifically, a total of about 10 milliliters of ink is ejected from the nozzle 81 of the inkjet head 80 and dropped into each region R. Next, the dummy and the ink applied to all the regions R are dried in vacuum. At this time, the organic solvent is volatilized as shown in FIG. In the present embodiment, since the dummy exists, the concentration of the organic solvent in the atmosphere near the edge of the substrate is close to the concentration of the organic solvent in the atmosphere near the center of the substrate. Further, the substrate 10 may be annealed to increase the degree of drying.

  As shown in FIG. 7, when the drying process is completed, as a result, a light emitting layer (organic thin film) 60 is formed in each region R on the substrate 10. Next, a counter electrode is formed on all the light emitting layers 60 and the partition walls 50 by a vacuum deposition method. The material of the pixel electrode 30 and the counter electrode is, for example, ITO (Indium Tin Oxide) or aluminum, and can be appropriately selected according to the emission type of the organic EL device. The light emitting layer 60 is made of an organic electroluminescent material, and is excited by the recombination of carriers between the pixel electrode 30 and the counter electrode to emit light.

  Next, sealing is performed. Thus, an organic EL device is manufactured. The counter electrode may be formed and sealed while the substrate 10 is placed on the drawing stage 70 or after the substrate 10 is lowered from the drawing stage 70. The drawing stage 70 can be used for manufacturing another organic EL device by cleaning.

  As described above, according to the first embodiment, in the ink drying process, the concentration of the organic solvent in the atmosphere near the edge of the substrate 10 is the concentration of the organic solvent in the atmosphere near the center of the substrate 10. Therefore, the drying speed of the ink is uniform over the entire region R, and the film thickness unevenness of the formed light emitting layer 60 is reduced. In addition, according to the first embodiment, since the organic solvent that is about 1/1000 of the total amount of ink to be arranged on the substrate 10 is arranged around the substrate 10, the thickness of the light emitting layer 60 is set to all regions. It can be uniform over R.

  Further, according to the first embodiment, it is not necessary to secure a space as a dummy region on the substrate 10. Therefore, according to the first embodiment, it is possible to reduce luminance unevenness and light emission color unevenness due to drying unevenness without hindering narrowing of the frame of the organic EL device. Further, according to the first embodiment, since the organic solvent is put into the groove 72 of the drawing stage 70, the positional relationship between the ink applied on the substrate 10 and the organic solvent arranged around the substrate 10 is determined. While maintaining, the amount of the organic solvent disposed around the substrate 10 can be adjusted.

<Second Embodiment>
FIG. 8 is a diagram for explaining a method of manufacturing the organic EL device according to the second embodiment of the invention. The positioning of FIG. 8 in the second embodiment is the same as the positioning of FIG. 6 in the first embodiment. As apparent from FIG. 8, the second embodiment is different from the first embodiment in that a drawing stage 90 is used instead of the drawing stage 70. The upper surface of the drawing stage 90 is flat over the entire area.

  In the second embodiment, an organic solvent is disposed on the drawing stage 90 in the first step. Specifically, a dummy organic solvent is applied to a region 91 that does not overlap the substrate 10 on the upper surface of the drawing stage 90. This coating method is arbitrary, and for example, it may be dropped with a dropper or may be ejected from an inkjet head. As a result, the dummy contacts the flat upper surface of the drawing stage 90.

  According to the second embodiment, the same effect as that of the first embodiment can be obtained. In addition, it is possible to directly use a drawing stage (a drawing stage whose entire upper surface is flat) conventionally used in the manufacturing process of an organic EL device using an inkjet method.

<Third Embodiment>
FIG. 9 is a diagram for explaining a method of manufacturing an organic EL device according to the third embodiment of the present invention. The positioning of FIG. 9 in the third embodiment is the same as the positioning of FIG. 8 in the second embodiment. As is clear from FIG. 9, the third embodiment is different from the second embodiment in that a drawing stage 90 to which a container 92 is attached is used.

  The container 92 has a bottom surface and a recess 93 that opens to the opposite side of the bottom surface. The entire bottom surface of the container 92 is in contact with a region 91 that does not overlap the substrate 10 such that the recess 93 opens upward. For this reason, the bottom of the recess 93 is positioned above the lower surface of the substrate 10 in a state where the substrate 10 is placed on the drawing stage 90. The attachment method of the container 92 to the drawing stage 90 is arbitrary, and for example, adhesion may be used.

  In the third embodiment, a dummy organic solvent is placed in the recess 93 in the first step. This insertion method is arbitrary, and for example, it may be dropped with a dropper or may be ejected from an inkjet head. The organic solvent put in the concave portion 93 accumulates in the concave portion 93 to become a dummy and volatilizes from the opening of the concave portion 93.

  According to the third embodiment, an effect similar to that of the first embodiment can be obtained. In addition, according to the third embodiment, a drawing stage conventionally used in the ink jet method (a drawing stage having a flat upper surface) can be used after simple processing (attachment of the container 92). it can. Further, according to the third embodiment, by removing the container 92, one drawing stage 90 can be used for manufacturing a plurality of types of organic EL devices having different substrate sizes.

<Fourth embodiment>
FIG. 10 is a diagram for explaining the method of manufacturing the organic EL device according to the fourth embodiment of the invention. The positioning of FIG. 10 in the fourth embodiment is the same as the positioning of FIG. 9 in the third embodiment. As is apparent from FIG. 10, the fourth embodiment is different from the third embodiment in that a drawing stage 95 is used instead of the drawing stage 90 to which the container 92 is attached. A concave portion 96 opened upward is formed in a portion of the drawing stage 95 that does not overlap the substrate 10. The concave portion 96 corresponds to the concave portion 93 in FIG. 9, and the bottom thereof is positioned above the lower surface of the substrate 10 when the substrate 10 is placed on the drawing stage 95.

  In the fourth embodiment, a dummy organic solvent is put into the recess 96 in the first step. This insertion method is arbitrary, and for example, it may be dropped with a dropper or may be ejected from an inkjet head. The organic solvent placed in the recess 96 accumulates in the recess 96 to become a dummy and volatilizes from the opening of the recess 96. According to the fourth embodiment, an effect similar to that of the third embodiment can be obtained. However, the recess 96 cannot be attached to or detached from the drawing stage 95.

<Fifth embodiment>
FIG. 11 is a diagram for explaining the method of manufacturing the organic EL device according to the fifth embodiment of the invention. The positioning of FIG. 11 in the fifth embodiment is the same as the positioning of FIG. 9 in the third embodiment. As apparent from FIG. 11, the fifth embodiment is different from the third embodiment in that a drawing stage 90 to which a container 97 is attached is used instead of the drawing stage 90 to which the container 92 is attached. Is a point.

  The container 97 has a bottom surface and a recess 98 opened to the opposite side of the bottom surface. The entire bottom surface of the container 97 is in contact with a region 91 that does not overlap the substrate 10 so that the recess 97 opens upward. A method for attaching the container 97 to the drawing stage 90 is arbitrary, and for example, adhesion may be used. The bottom of the container 97 is thicker than the bottom of the container 92. Further, the top surface of the bottom of the container 97, that is, the bottom of the recess 98 is positioned above the top surface of the substrate 10 in a state where the substrate 10 is placed on the drawing stage 90.

  In the fifth embodiment, a dummy organic solvent is placed in the container 97 in the first step. That is, it is put in the recess 98. This insertion method is arbitrary, and for example, it may be dropped with a dropper or may be ejected from an inkjet head. The organic solvent put in the concave portion 98 accumulates in the concave portion 98 to become a dummy and volatilizes from the opening of the concave portion 98. At this time, the lower end of the dummy is positioned above the upper surface of the substrate 10 placed on the drawing stage 90.

  According to the fifth embodiment, an effect similar to that of the third embodiment can be obtained. In addition, according to the fifth embodiment, the dummy volatile surface is arranged at the end of the substrate 10 as compared with the embodiment in which the lower end of the dummy is positioned below the upper surface of the substrate 10 placed on the drawing stage 90. Since it becomes easy to approach the volatile surface of the ink applied in the region R of the portion, the amount of the dummy organic solvent can be reduced.

<Modification>
The scope of the present invention includes not only the above-described embodiment but also the following modifications.
For example, each embodiment described above may be modified to use ink instead of an organic solvent as a dummy. In this case, when the drying process is completed, an organic thin film is formed on a portion of the drawing stage that does not overlap the substrate 10. For example, when such a modification is performed on the first embodiment, the organic thin film 65 is formed in the recess 72 of the drawing stage 70 as shown in FIG.

  Further, for example, the third embodiment (FIG. 10) is modified, and the lower end of the dummy is higher than the upper surface of the substrate 10 placed on the drawing stage as in the fifth embodiment (FIG. 11). You may make it locate in. Further, in this modification and the fifth embodiment, the lower end of the dummy may be positioned above the upper surface of the layer 20, or may be positioned above the upper surface of the pixel electrode 30. Also good.

  Further, for example, the above-described embodiments and the above-described modifications may be modified as follows. For example, a dispenser may be used for ink application instead of the inkjet method. That is, the present invention is applicable to a so-called wet process. Further, for example, a light emitting device in which organic EL elements having a structure in which a plurality of organic thin films are sandwiched between a pixel electrode and a counter electrode is arranged in a matrix may be manufactured. Examples of the organic thin film other than the light emitting layer include a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer. For example, an organic EL device (for example, an exposure head of an electrophotographic printer) in which organic EL elements having a structure in which an organic thin film is sandwiched between a pixel electrode and a counter electrode is arranged in a line may be manufactured. It is good also as a form which manufactures the organic EL apparatus which uses this organic EL element as a light source of illumination.

<Application example>
Next, an electronic apparatus to which the organic EL device according to each of the above embodiments or each of the above modifications (hereinafter referred to as “the present organic EL device”) is applied will be described. In addition, since the electronic device to which the present organic EL device is applied is also a device having the organic EL device, it is included in the organic EL device according to the present invention.
FIG. 13 is a perspective view showing a configuration of a mobile personal computer using the organic EL device as an image display device. The personal computer 2000 includes the present organic EL device as a display device and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002.
FIG. 14 shows a mobile phone to which the present organic EL device is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and the present organic EL device as a display device. By operating the scroll button 3002, the screen displayed on the organic EL device is scrolled.
FIG. 15 shows an information portable terminal (PDA: Personal Digital Assistant) to which the organic EL device is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and the present organic EL device as a display device. When the power switch 4002 is operated, various kinds of information such as an address book and a schedule book are displayed on the organic EL device.

  Electronic devices that can use this organic EL device as a display device include those shown in FIGS. 13 to 15, digital still cameras, televisions, video cameras, car navigation devices, pagers, electronic notebooks, electronic papers, calculators. , A word processor, a workstation, a videophone, a POS terminal, a video player, a device equipped with a touch panel, and the like. Of course, an electrophotographic printer (image printing apparatus) using the organic EL device as an exposure head, a device using a lighting device, and the like are also included in the above electronic devices.

It is sectional drawing which shows the 1st process of the manufacturing method of the organic electroluminescent apparatus concerning the 1st Embodiment of this invention. FIG. 2 is a cross-sectional view showing a step subsequent to FIG. 1. It is a top view which shows the process of FIG. FIG. 4 is a cross-sectional view showing a step subsequent to FIG. 2 and FIG. 3. FIG. 5 is a cross-sectional view showing a step subsequent to FIG. 4. FIG. 6 is a cross-sectional view showing a step subsequent to FIG. 5. It is sectional drawing which shows the result of the process of FIG. It is a figure for demonstrating the manufacturing method of the organic electroluminescent apparatus concerning the 2nd Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the organic electroluminescent apparatus concerning the 3rd Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the organic electroluminescent apparatus concerning the 4th Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the organic electroluminescent apparatus concerning the 5th Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the organic electroluminescent apparatus which concerns on the modification of each embodiment of this invention. It is a perspective view which shows the external appearance of the personal computer which has the organic electroluminescent apparatus which concerns on each embodiment or its modification of this invention. It is a perspective view which shows the external appearance of the mobile telephone which has the organic electroluminescent apparatus which concerns on each embodiment or its modification of this invention. It is a perspective view which shows the external appearance of the portable information terminal which has the organic electroluminescent apparatus which concerns on each embodiment or its modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Substrate, 20 ... Layer, 21 ... TFT, 22 ... Conductor, 30 ... Pixel electrode, 40 ... Underlayer, 5 ... Intermediate, 50 ... Partition, 60 ... Light emitting layer (organic thin film), 65 ... Organic thin film, 70 , 90, 95 ... drawing stage (stage), 71 ... central portion, 72 ... groove (concave), 80 ... inkjet head, 81 ... nozzle, 91, R ... area, 92, 97 ... container, 93, 96, 98 ... Recess.

Claims (1)

In a method for manufacturing an organic electroluminescence device having a substrate and an organic thin film formed on the substrate,
And has a recess upwardly open, put the substrate to the container is not mounted portion in detachable stage container is mounted step,
Placing the ink containing the organic thin film material and the organic solvent or the organic solvent in the recess of the container;
The ink or on the said substrate an organic solvent is placed on the placed the stage, the region for forming the organic thin film, have a a step of applying the ink,
The manufacturing method , wherein the pixel electrode of the pixel electrode and the counter electrode sandwiching the organic thin film is formed, and the bottom of the recess is located above the upper surface of the layer provided on the substrate .

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