JP4626391B2 - Method for manufacturing organic electroluminescent element, organic electroluminescent element, and apparatus using organic electroluminescent element - Google Patents

Description

  The present invention uses a method for producing an organic electroluminescence element (hereinafter also referred to as an organic EL element), which is an electroluminescent element used for a display using an organic semiconductor film, a display light source, and the like, an organic EL element, and an organic EL element Related to the device.

  In recent years, the development of light-emitting elements using organic substances has been accelerated as a spontaneous emission type display that replaces a liquid crystal display. As an organic EL element using an organic substance, Appl. Phys. Lett. 51 (12), 21 September 1987, page 913, a method of depositing a low molecule by a vapor deposition method, Appl. Phys. Lett. 71 (1), 7 July 1997, as described from page 34, a method of applying a polymer is mainly reported. There are two types of driving methods for pixels of organic EL elements: a passive method using line sequential driving and an active method using TFT (Thin Film Transistor) driving, and it is said that the active method is becoming mainstream. In the case of the passive method, pixels are arranged in a matrix by applying a DC voltage to a metal cathode formed in a stripe shape orthogonal to an ITO (Indium Tin Oxide) electrode (anode) formed in a stripe shape on a glass substrate. It is displayed by emitting light.

  In the case of the active method, the matrix pixels formed in accordance with the TFTs arranged in a grid pattern are caused to emit light by driving the TFTs for display. Therefore, in the case of the active method, a technique for patterning a luminescent material in accordance with TFTs arranged in a lattice shape is required.

  In the case of using a low molecular weight material for the active method, a method is used in which a mask corresponding to a required pattern is used, and a different light emitting material is deposited and formed on a desired pixel through the mask. On the other hand, when a polymer material is used, colorization using an ink jet method has attracted attention because patterning can be performed minutely and easily. Examples of the formation of the organic EL element by the ink jet method include, for example, JP-A-7-235378, JP-A-10-12377, JP-A-10-153967, JP-A-11-40358, JP-A-11-54270, JP-A-11-54270. The method described in 11-339957 etc. is known.

  However, application of patterning to the organic EL element by the ink jet method is efficient and leads to cost reduction. However, it is highly expected. On the other hand, the flight of the ejected droplet is bent, the shape of the droplet is stabilized, and the minute droplet Therefore, it cannot be said that it is at a level sufficient to directly draw a high-precision fine pattern required for an organic EL element. Therefore, when the ink jet method is applied to such an electronic device, in order to cover the discharge accuracy of the ink jet method, for example, as described in JP-A-2000-353594, an opening is provided on the substrate. There is known a method of patterning a functional material by forming a partition (bank) and discharging droplets to an opening formed by the partition.

  The partition wall is generally coated with a photosensitive synthetic resin on a substrate to provide a photosensitive material layer (insulating layer), and then a mask having a pattern corresponding to the opening is illuminated with exposure light. A photolithography method is known in which a photosensitive material layer is exposed to transmitted exposure light and then developed to form partition walls.

  Since the method for forming the partition wall is configured to expose the photosensitive material layer with the exposure light transmitted through the mask, a photosensitive material layer is provided to irradiate the photosensitive material layer with the exposure light at a desired position. An alignment process between the substrate and the mask is required. As described above, since a process for alignment processing is required, throughput is reduced and an exposure apparatus provided with an alignment apparatus, a so-called stepper is required. Furthermore, the stepper is configured to sequentially perform exposure processing while stepping and repeating a plurality of shot areas. However, as the substrate size increases, the number of shots increases and throughput decreases.

  In addition, the material used for the barrier ribs has low photosensitivity, so it must be exposed for a long time, which puts a burden on the stepper and may require frequent maintenance of the optical system or damage the stepper in an expensive stepper. It becomes disadvantageous in terms of cost, such as higher. Various countermeasures have been taken against such problems of the photolithography method.

  For example, the donor sheet on which the transfer material is formed and the transparent substrate on which the pixel electrode is formed are brought into close contact, and the partition pattern is transferred onto the transparent substrate by performing laser irradiation corresponding to the pixel partition pattern from the donor sheet side. A laser photothermal transfer method is known (see, for example, Patent Document 1). However, in the technique described in Patent Document 1, since the donor sheet and the pixel electrode are brought into close contact with each other, it is assumed that the adhesiveness becomes very important. In the case of poor adhesion, there is a possibility that the yield of the pixel electrode substrate will not increase if uneven transfer occurs.

  Further, a photolithography method is known in which a light shielding portion is provided in advance on a substrate and exposure is performed from the back surface of the substrate using the light shielding portion as a mask to improve the throughput for forming the partition wall (see, for example, Patent Document 2). ). However, since Patent Document 2 exposes from the back surface of the substrate, it is assumed that the exposure accuracy is not so high. Further, it is necessary to overlap the light shielding portion and the pixel electrode, and the manufacturing process including the alignment may become very complicated.

  After forming the transparent electrode, a silicon resin mold with grooves in the shape of the bank (partition) is brought into close contact with the substrate, and a liquid raw material for the bank (partition) is infiltrated into the resulting space and solidified after filling. A method of removing the silicon resin mold after solidification and forming banks (partition walls) is known (see, for example, Patent Document 3). However, although the method described in Patent Document 3 can solve the problem of ejection accuracy of the ink jet method and can be simplified as compared with photolithography, the process is complicated because it is performed through a silicon resin mold. It is assumed that productivity will not increase so much.

In such a situation, the manufacturing process is simple, the productivity is high, and the pixels that are patterned by the partition formed using the stable partition forming method are used to partition the pixels that are formed using the inkjet method. The development of a method for producing an organic EL element that forms the organic EL element and an organic EL element are desired.
JP 2001-130141 A JP 2004-63286 A Japanese Patent Laid-Open No. 11-74076

  The present invention has been made in view of the above circumstances, and its object is to form a pattern on a substrate by partition walls formed using a partition wall formation method that is simple in manufacturing process, high in productivity, and stable. And a device using an organic EL element and a method for manufacturing an organic EL element that forms a stable pixel by using a droplet discharge method in each compartment. .

  The above object of the present invention has been achieved by the following constitution.

(Claim 1)
An organic electroluminescence device having an organic compound layer including at least one light emitting layer and a second electrode on a pixel electrode partitioned by a plurality of grid-like partition walls formed on a substrate; and a pixel electrode forming step; In the method for manufacturing an organic electroluminescence element manufactured by a manufacturing apparatus having a partition wall forming step, an organic compound layer forming step, and a second electrode forming step,
Between the pixel electrode forming step and the partition wall forming step , a surface cleaning process, a surface modification process and a charge removal process are performed on the substrate, and the partition wall is formed by an electrostatic suction nozzle discharge method,
The method of manufacturing an organic electroluminescence element, wherein the light emitting layer is formed on the pixel electrode by a droplet discharge method in the organic compound layer forming step.

(Claim 2)
The method for manufacturing an organic electroluminescent element according to claim 1, wherein the partition wall has a width of 5 to 20 μm.

(Claim 3)
3. The organic electroluminescence element according to claim 1, wherein a volume per droplet of the partition wall material solution ejected by the electrostatic suction nozzle ejection method is 0.05 to 1 pl (picoliter). Production method.

(Claim 4)
4. The method of manufacturing an organic electroluminescence element according to claim 1, wherein a nozzle diameter (inner diameter) of a discharge nozzle used in the electrostatic suction nozzle discharge method is 3 to 10 μm. .

(Claim 5)
The method of manufacturing an organic electroluminescence element according to claim 1, wherein the substrate is a flexible substrate.

(Claim 6)
The organic compound layer forming step forms the other organic compound layers excluding the light emitting layer by any one of a vacuum deposition method, a wet film formation method, and a droplet discharge method. The manufacturing method of the organic electroluminescent element of any one of these.

(Claim 7)
The said light emitting layer has a phosphorescent compound, The manufacturing method of the organic electroluminescent element in any one of Claims 1-6 characterized by the above-mentioned.

(Claim 8)
An organic electroluminescent device manufactured by the method for manufacturing an organic electroluminescent device according to claim 1.

(Claim 9)
An organic electroluminescence device using the organic electroluminescence element produced by the method for producing an organic electroluminescence element according to any one of claims 1 to 7.

  The manufacturing process is simple, the productivity is high, and a stable pixel is formed by using a droplet discharge method in each section that partitions a pixel patterned by a partition formed using a stable partition forming method. A manufacturing method of an organic EL element, an organic EL element, and a device using the organic EL element can be provided, and production of a stable and high-quality organic EL element and a device using the organic EL element has become possible.

  Embodiments according to the present invention will be described with reference to FIGS. 1 to 7, but the present invention is not limited thereto.

  FIG. 1 is a schematic flow diagram for manufacturing an organic EL element.

  As shown in this figure, the organic EL element is manufactured through a schematic pixel electrode forming step, a partition wall forming step, an organic compound layer forming step, a second electrode forming step, and a sealing layer forming step. In this figure, in the organic compound layer forming step, hole transport layer formation and light emitting layer formation are performed. This will be described with reference to the flowchart below.

  In S1, the TFT that is the pixel electrode and the first electrode are patterned and formed in the pixel electrode forming step on the substrate supplied from the base material supplying step.

In S2, since the surface of the ITO (first electrode), which is a pixel electrode patterned and formed on the substrate, is cleaned before the hole transport layer is formed, the substrate cleaning processing apparatus (not shown) is used. Thereafter, a charge removal process is performed. For example, a low-pressure mercury lamp, an excimer lamp, or a plasma cleaning apparatus is preferably used as the substrate cleaning processing apparatus. Examples of the conditions for the substrate cleaning treatment using the low-pressure mercury lamp include conditions for performing substrate cleaning by irradiating a low-pressure mercury lamp with a wavelength of 184.2 nm at an irradiation intensity of 5 to ²⁰ mW / cm ² and a distance of 5 to 15 mm. For example, atmospheric pressure plasma is preferably used as a condition for the substrate cleaning process by the plasma cleaning apparatus. Examples of the cleaning conditions include conditions in which a gas containing 1 to 5% by volume of oxygen is used as the argon gas, and the substrate cleaning process is performed at a frequency of 100 KHz to 150 MHz, a voltage of 10 V to 10 KV, and an irradiation distance of 5 to 20 mm. As the charge removing means, a non-contact type charge removing device (not shown) and a contact type charge removing device (not shown) are preferably used, and a non-contact type charge removing device (not shown) is provided on the pixel electrode side. It is preferable to apply a contact type charge removing device (not shown) to the side. Examples of the non-contact type charge removing device include a non-contact type ionizer. The type of ionizer is not particularly limited, and the ion generation method may be either an AC method or a DC method. An AC type, a double DC type, a pulsed AC type, and a soft X-ray type can be used, but the AC type is particularly preferable from the viewpoint of precise static elimination. Air or N ₂ is used as the injection gas required when using the AC type, but it is preferable to use N ₂ with sufficiently high purity. From the viewpoint of in-line operation, the blower type or the gun type is selected.

  As the contact-type charge removing device, a static eliminating roll or a grounded conductive brush is used. A static elimination roll as a static elimination machine is grounded, and rotates in contact with the static eliminated surface to remove surface charges. Such static elimination rolls include rolls made of elastic plastic or rubber mixed with conductive materials such as carbon black, metal powder, and metal fibers in addition to rolls made of metal such as aluminum, copper, nickel, and stainless steel. used. In particular, an elastic material is preferable in order to improve contact with the substrate. Examples of the conductive brush connected to the earth include a neutralizing bar or a neutralizing yarn structure having a brush member made of conductive fibers arranged in a line or a linear metal brush. The neutralization bar is not particularly limited, but a corona discharge type is preferably used. For example, SJ-B manufactured by Keyence Corporation is used. There is no particular limitation on the static elimination yarn, but usually a flexible yarn is preferably used. For example, 12/300 × 3 manufactured by Naslon can be cited as an example.

  In S3, after the partition wall forming liquid is discharged by the electrostatic suction nozzle discharge method between the pixel electrodes (see FIG. 2) formed by patterning on the substrate in the partition wall forming step, drying and heating processes are performed. A partition is formed. Then, after performing a charge removal process, it is sent to the next step. The charge removal process is performed by the same method as the charge removal process shown in S2. The electrostatic suction nozzle discharge method will be described in detail with reference to FIGS. The barrier ribs may be formed after the hole transport layer is formed, and are appropriately selected as necessary.

  In S4, the hole transport layer is formed by applying a solution for hole transport layer to each section partitioned by the partition in the organic compound layer forming step by a droplet discharge method, followed by drying and heat treatment. The Then, after performing a charge removal process, it is sent to the next step. The charge removal process is performed by the same method as the charge removal process shown in S2. In addition, when the hole transport layer is already formed, it becomes unnecessary. Examples of the droplet discharge method include an inkjet method, a dispenser method, and an electrostatic suction nozzle discharge method.

  In S5, the light emitting layer solution is formed by applying the solution for the light emitting layer on the hole transport layer already formed in each section partitioned by the partition walls by the droplet discharge method, followed by drying and heat treatment. Then, after carrying out the charge removal treatment, it is sent to the next step. The charge removal process is performed by the same method as the charge removal process shown in S2. Examples of the droplet discharge method include an inkjet method, a dispenser method, and an electrostatic suction nozzle discharge method.

  In S6, an electron transport layer is formed on the light emitting layer by a vapor deposition method using a mask that matches the patterning of the barrier ribs formed on the substrate.

  In S7, a second electrode is formed on the electron transport layer by vapor deposition using a mask that matches the patterning of the barrier ribs formed on the substrate in the second electrode formation step. The method for forming the electron transport layer and the second electrode is not particularly limited. For example, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In S8, the sealing layer is formed on the second electrode in the sealing layer forming step, and the organic EL element is manufactured. The sealing layer may be formed by a vapor deposition method, or the sealing film may be attached with an adhesive.

  The present invention relates to a method for manufacturing an organic EL element using an electrostatic suction nozzle discharge method instead of a conventional ink jet method for forming an organic EL element for which higher precision is required.

  FIG. 2 is a partial schematic view of an active organic EL element. FIG. 1A is a partial schematic perspective view of an active organic EL element. FIG. 1B is a schematic cross-sectional view taken along the line AA ′ of FIG.

  In the figure, 1 indicates an organic EL element. The organic EL element has a plurality of grid-like sections 101 formed by partition walls 102a and 102b provided on a substrate 103, and TFTs 104a and ITO electrodes (anodes) 104b provided in the sections. An organic compound layer 105 having a pixel electrode 104, a hole transport layer 105a, a light emitting layer 105b, and an electron transport layer (not shown), a first insulating layer 106, a second insulating layer 107, and a cathode layer 108. Have.

  In the present invention, a plurality of grid-like sections are formed by the partition walls 102a (102b) and the partition walls 102a (102b) shown in this figure, and an organic EL layer 105 is formed in the formed sections to form an organic EL. The present invention relates to an organic EL element manufacturing method for manufacturing an element, an organic EL element, and an organic EL device using the organic EL element.

  The present invention is a method of manufacturing the organic EL element shown in the figure by a manufacturing apparatus having a pixel electrode forming step, a partition wall forming step, an organic compound layer forming step, and a second electrode forming step. In the forming process, the pixel electrode is partitioned by forming a partition wall by the electrostatic suction nozzle discharge method in the partition forming process around the pixel electrode formed on the substrate, and on the partitioned pixel electrode in the organic compound layer forming process. An organic compound layer 105 having a hole transport layer 105a, a light emitting layer 105b, and an electron transport layer (not shown) is formed, and a cathode layer 108 is formed on the electron transport layer (not shown) in the second electrode forming step. The present invention relates to an organic EL element manufacturing method for manufacturing an organic EL element by forming, an organic EL element, and an organic EL device using the organic EL element. Each layer constituting the organic compound layer 105 may be a plurality of layers.

  FIG. 3 is a schematic plan view showing a state of lattice-shaped partition walls formed so as to surround a plurality of pixel electrodes formed on the substrate.

  In the figure, reference numeral 2 denotes a substrate having grid-like partition walls. R indicates the width of the partition wall in the horizontal direction, and the width R is set so that the film formation area becomes larger than the effective pixel area in order to suppress the influence of film thickness unevenness generated at the center and end of the droplet. It is preferable to set it as 5-20 micrometers, Furthermore, 5-10 micrometers is more preferable. S indicates the width of the partition wall in the vertical direction, and the width R is preferably the same as the width of the partition wall in the horizontal direction. T indicates the interval between the partition walls 102b, and U indicates the interval between the partition walls 102a. Since the pixel size varies depending on the usage, the interval T and the interval U cannot be generally specified, but are preferably 30 to 150 μm, and more preferably 50 to 100 μm.

  The height of the partition wall 102a (102b) is preferably set in accordance with the thickness of the organic compound layer provided in the section formed by each partition wall. Other symbols are the same as those in FIG.

  FIG. 4 is a schematic diagram of the electrostatic suction nozzle discharge method apparatus for forming the grid-like partition walls shown in FIG.

  In the figure, reference numeral 3 denotes an electrostatic suction nozzle discharge device. The electrostatic suction nozzle ejection device 3 includes a substrate mounting table 302 for supporting a substrate 103 having pixel electrodes 104 arranged in a pattern, and a partition wall that is disposed above the substrate mounting table 302 and can be charged. From a liquid ejection device 301 in which an ultrafine nozzle 301 a (see FIG. 5) for ejecting a forming solution (hereinafter simply referred to as a solution) is directed to the substrate mounting table 302. In the case where the droplets ejected and adhered to the substrate are of a thermosetting type, it is preferable to have a curing means (for example, a heater, ultraviolet irradiation) 303 that cures the landed droplets. Either one of the substrate mounting table 302 and the liquid ejection device 301 can be moved in the XY directions (arrow directions in the figure) by a moving means (not shown). The curing means 303 is also disposed on an attachment frame (not shown) of the liquid ejection device 301 so as to be movable in the XY direction (arrow direction in the drawing) together with the liquid ejection device 301. The liquid ejecting apparatus 301 may be a line type liquid ejecting apparatus in which a plurality of nozzles are arranged, and can be appropriately selected as necessary. Reference numerals 302 a to 302 d denote holding jigs for the substrate 103 disposed on the substrate mounting table 302. The holding jigs 302a to 302d are arranged at the four corners of the substrate mounting table 302 so that the substrate 103 can be moved in accordance with the movement of the liquid ejection device 301 in the X-axis and Y-axis directions (arrow directions in the drawing). It can be moved according to the size of the board to be installed. Reference numeral 4 denotes a counter electrode. The counter electrode will be described with reference to FIG. The liquid ejection device 301 will be described in detail with reference to FIG.

  There are the following two methods for forming the grid-shaped partition walls shown in FIG. 2 by using the electrostatic suction nozzle discharge device 3 shown in this figure. 1) A plurality of pixel electrodes formed by patterning on a substrate by fixing the substrate mounting table 302 and attaching the liquid ejection device 301 to a robot movable in the X-axis and Y-axis directions (arrow directions in the figure). A method for forming a partition by discharging a partition forming liquid from the liquid discharge device 301 in the meantime. At this time, the substrate mounting table 302 is provided with a holding jig at a position corresponding to the movement of the liquid ejection device 301 in the X-axis and Y-axis directions (arrow directions in the drawing). It is necessary to place it. 2) The liquid ejection device 301 is fixed, and the substrate mounting table 302 is moved in the X-axis and Y-axis directions (arrow directions in the figure), so that the plurality of pixel electrodes formed on the substrate are patterned. A method of forming a partition by discharging a partition forming liquid from the liquid discharge device 301. At this time, it is necessary to provide the substrate mounting table 302 with an index that matches the X-axis and Y-axis directions (arrow directions in the drawing) of the substrate mounting table 302, and to mount the substrate in accordance with the index. Which of the methods 1) and 2) shown above can be used can be appropriately selected as necessary.

  The partition walls as shown in FIGS. 3 and 4 need to be disposed between the light emitting layers formed on the pixel electrodes. For example, when a gas barrier film is provided between the pixel electrodes and the substrate. Is provided on the gas barrier film on the substrate when the gas barrier film is not provided, and on the hole transport layer when the hole transport layer is provided on the entire surface of the substrate on the pixel electrode. It is possible to select appropriately according to the configuration of the organic EL element to be manufactured.

  When the hole transport layer is provided on the entire surface of the substrate, it can be appropriately selected from a vacuum deposition method, a wet film formation method, and a droplet discharge method. Among these, the wet film formation method is preferable, and the hole transport layer coating solution is spin-coated. A method, a die coating method, a screen printing method, a flexographic printing method, a Mayer bar method, a cap coating method, a spray coating method, a casting method, a roll coating method, a bar coating method, a gravure coating method, and the like can be used. It can be suitably selected according to the material of the hole transport layer.

  Examples of the method for forming the organic compound layer in the partition include various methods such as a vacuum deposition method, a wet film formation method, and a droplet discharge method. Examples of the organic compound layer formed in the partition include a hole transport layer, a light emitting layer, and an electron transport layer. Among these organic compound layers, the light emitting layer is a droplet discharge method such as an inkjet method, a dispenser method, or an electrostatic suction nozzle discharge method, and other layers (hole transport layer, electron transport layer, etc.) excluding the light emitting layer are It is preferably formed by a vacuum deposition method, a wet film formation method, or a droplet discharge method.

  The partition walls as shown in FIGS. 3 and 4 are members that function as partition members, and the partition walls can be suitably formed by an electrostatic suction nozzle discharge method. By using the electrostatic suction nozzle discharge method, the organic photosensitive material is selected and applied directly on the substrate according to the height of the partition walls, which makes it difficult to apply conventional resist coating, mask exposure / development, and etching. Can be simplified. At this time, by setting the internal diameter of the head nozzle used in the electrostatic suction nozzle discharge method to 20 μm or less, the electric field concentration effect between the nozzle electrode and the lower electrode can be used, so that highly accurate patterning is possible. Become.

  Immediately before the barrier rib is formed, it is preferable to perform a substrate cleaning process for removing organic contamination adhered to the substrate surface in order to make the wettability of the landing droplets uniform in the electrostatic suction nozzle discharge method. At the same time, the surface modification of the ITO substrate can be performed, and there is an effect of reducing the element driving voltage and an effect of increasing the light emission efficiency. As the substrate cleaning process, for example, a low-pressure mercury lamp, an excimer lamp, a UV ozone process, a plasma process, or the like is effective.

  In addition, in order to prevent flying droplets from being disturbed in the electrostatic suction nozzle discharge method, it is preferable to perform a charge removal process for removing the surface potential accumulated on the substrate. At the same time, it works to prevent dust adhesion and dielectric breakdown, and has the effect of improving yield. Examples of the charge removal treatment method include a light irradiation method and a corona discharge method. The light irradiation type generates weak ions by the weak X-rays, and the corona discharge type generates air ions by corona discharge, and the air ions are attracted to the charged object to compensate for charges of opposite polarity, and static electricity can be neutralized. Other symbols are the same as those in FIG.

FIG. 5 is an enlarged schematic cross-sectional view of the liquid ejection device along BB ′ in FIG. 4.
(Overall configuration of liquid ejection device)
The liquid ejection device 301 has an ultra-fine nozzle 301a that ejects droplets of a chargeable solution from its tip, a facing surface that faces the tip of the nozzle 301a, and droplet landing on the facing surface. The counter electrode 4 that supports the receiving substrate 302, a solution supply unit that supplies a solution to the flow path 301a1 in the nozzle 301a, and a discharge voltage application unit 301b that applies a discharge voltage to the solution in the nozzle 301a are provided. Note that a part of the configuration of the nozzle 301a and the solution supply unit and a part of the configuration of the discharge voltage applying unit 301b are integrally formed by the nozzle plate 301c1.

The nozzle 301a1 is integrally formed with an upper surface layer of a nozzle plate 301c1 to be described later, and is erected vertically from the flat plate surface of the nozzle plate 301c. Further, the nozzle 301a is formed with an in-nozzle flow path 301a1 penetrating from the tip portion along the center line. Reference numeral 301a2 denotes a droplet ejected from the nozzle flow path 301a1.
The volume of the droplet 301a2 is 0.05 pl (picoliter) to 1 pl (in consideration of the wetting and spreading diameter of the landed droplet, the coalescence between the droplets, the line width after coalescence, and the like when forming and rubbing the partition wall. Picoliter) is preferred. The volume of the droplet is the equivalent diameter obtained by shooting the droplet ejected from the nozzle and flying using an ultra high-speed camera, treating the droplet as a sphere, processing the two-dimensional image, and converting the area of the droplet into a circle. And calculated from the obtained diameter. Here, for example, methods disclosed in Japanese Patent Application Laid-Open Nos. 2001-150658, 2001-150659, and 2001-150696 can be applied to the method for measuring the diameter of the droplets. Specifically, a droplet enlarged through a high-magnification lens is imaged on an image sensor, and a signal output from the image sensor is subjected to image processing. Then, the outer diameter of the droplet was recognized from the density value of the outer shape portion of the droplet of the image information subjected to image processing, and the outer diameter was used as the diameter of the droplet.

The distance from the tip of the nozzle to the surface of the substrate on which the ejected droplets land is preferably 10 to 500 μm in consideration of the electric field concentration strength, mechanical accuracy, and the like.
(nozzle)
The nozzle 301a will be described in further detail. The nozzle 301a is formed with an ultrafine diameter as described above. The inner diameter of the nozzle is in a range in which a discharge voltage that enables discharge of droplets by the effect of electric field concentration described later is less than 1000 V, and preferably has a diameter of 20 μm or less. More preferably, it is 8 micrometers or less, More preferably, it is 4 micrometers or less, and it is preferable that it is larger than 0.2 micrometers. The inner diameter of the nozzle refers to the inner diameter of the tip of the nozzle flow path 301a1. By setting the inner diameter of the nozzle to 20 μm or less, the electric field strength distribution becomes narrow. As a result, the electric field can be concentrated. As a result, the formed droplets can be made minute and the shape can be stabilized, and the total applied voltage can be reduced. In addition, immediately after the droplet is ejected from the nozzle, the droplet is accelerated by an electrostatic force acting between the electric field and the electric charge. However, when the droplet is separated from the nozzle, the electric field rapidly decreases, and thereafter, the droplet is decelerated due to air resistance. However, a droplet that is a minute droplet and has a concentrated electric field is accelerated by mirror image force as it approaches the counter electrode. By balancing the deceleration due to the air resistance and the acceleration due to the mirror image force, it is possible to stably fly the fine droplets and improve the landing accuracy. The internal diameter of the nozzle is preferably 8 μm or less. By setting the internal diameter of the nozzle to 8 μm or less, it becomes possible to further concentrate the electric field, and further reduce the size of the droplets and reduce the influence of fluctuations in the distance of the counter electrode on the electric field intensity distribution during flight. Therefore, it is possible to reduce the influence of the position accuracy of the counter electrode, the characteristics of the base material, and the thickness on the droplet shape and the landing accuracy. Furthermore, by making the internal diameter of the nozzle 4 μm or less, it is possible to achieve a remarkable electric field concentration, to increase the maximum electric field strength, to make the shape of the droplet extremely fine, The initial discharge speed can be increased. Thereby, by improving the flight stability, it is possible to further improve the landing accuracy and improve the ejection response.
The inner diameter of the nozzle is preferably larger than 0.2 μm. By making the inner diameter of the nozzle larger than 0.2 μm, the charging efficiency of the liquid droplets can be improved, so that the discharge stability of the liquid droplets can be improved.
(Solution supply means)
The solution supply means is provided inside the nozzle plate 301c1 at a position that becomes the root of the nozzle 301a, and communicates the solution from the external solution tank (not shown) to the solution chamber 301d. A supply path 301e for guiding and a supply pump (not shown) for applying a supply pressure of the solution to the solution chamber 301d are provided. The supply pump can supply the solution to the tip of the nozzle 301a and maintain the supply pressure in a range that does not spill from the tip.
(Discharge voltage application means)
The discharge voltage applying means 301b includes a discharge electrode 301b1 for applying a discharge voltage provided in a boundary position between the solution chamber 301d and the nozzle flow path 301a1 inside the nozzle plate 301c1, and a direct current is always applied to the discharge electrode 301b1. And a discharge power supply 301b3 for applying a pulse voltage to the discharge electrode 301b1 to be a potential required for discharge superimposed on the bias voltage. The discharge electrode 301b1 can also be formed by plating.

  The discharge electrode 301b1 directly contacts the solution inside the solution chamber 301d to charge the solution and apply a discharge voltage. It is preferable to drive the voltage V applied to the nozzle in the basin represented by Equation 1.

Γ: surface tension of liquid, ε ₀ : dielectric constant of vacuum, r: nozzle radius, h: distance between nozzle and substrate, k: proportional constant depending on nozzle shape (1.5 <k <8.5) ).
The bias voltage by the bias power supply 301b2 is applied in a constant manner within a range where the solution is not discharged, thereby reducing the width of the voltage to be applied at the time of discharge, thereby improving the reactivity at the time of discharge. Yes.

  The discharge voltage power supply 301b3 applies the pulse voltage superimposed on the bias voltage only when discharging the solution. At this time, the value of the pulse voltage is set so that the superimposed voltage V satisfies the condition of the following expression (3).

However, γ: surface tension of solution, ε ₀ : dielectric constant of vacuum, r: nozzle radius, k: proportional constant (1.5 <k <8.5) depending on nozzle shape.

  As an example, the bias voltage is applied at 300V DC and the pulse voltage is applied at 100V. Therefore, the superimposed voltage at the time of ejection is 400V.

  The arbitrary waveform voltage to be applied is preferably 1000 V or less, and the arbitrary waveform voltage to be applied is preferably 500 V or less.

  When the solution is ejected from the nozzle 301a by a single pulse, a pulse width Δt greater than the constant τ determined by Equation 2 may be applied.

In the formula, ε is the dielectric constant of the fluid, and σ is the conductivity.
(Liquid discharge head)
The liquid discharge head 301c includes a base layer 301c3, a flow path layer 301c3 that forms a solution supply path located thereon, and a nozzle plate 301c1 that is an upper surface layer formed further above the flow path layer 301c3. The discharge electrode 301b1 described above is interposed between the flow path layer 301c3 and the upper surface layer (nozzle plate 301c1).

  The base layer 301c2 is formed of a silicon substrate or a highly insulating resin or ceramic, forms a soluble resin layer on the base layer 301c2, and removes and removes only portions that follow the pattern of the supply path 301e and the solution chamber 301d. An insulating resin layer is formed on the formed part. This insulating resin layer becomes the flow path layer 301c3. A discharge electrode 301b1 is formed on the upper surface of the insulating resin layer by plating with a conductive material (for example, NiP), and an insulating resist resin layer is further formed thereon. Since this resist resin layer becomes the upper surface layer (nozzle plate 301c1), this resin layer is formed with a thickness in consideration of the height of the nozzle 301a. Then, this insulating resist resin layer is exposed by an electron beam method or a femtosecond laser to form a nozzle shape. The in-nozzle flow path 301a1 is also formed by laser processing. The dissolvable resin layer according to the pattern of the supply path 301e and the solution chamber 301d is removed, and the supply path 301e and the solution chamber 301d are opened to complete the liquid discharge head.

(Counter electrode)
The counter electrode 4 has a counter surface perpendicular to the nozzle 301a, and supports the substrate 302 along the counter surface. As an example, the distance from the tip of the nozzle 301a to the opposing surface of the counter electrode 4 is set to 100 μm. Since the counter electrode 4 is grounded, the ground potential is always maintained. Therefore, when a pulse voltage is applied, a droplet ejected by an electrostatic force generated by an electric field generated between the tip of the nozzle 301a and the opposing surface is guided to the opposing electrode 4 side. The liquid ejection device 301 ejects liquid droplets by increasing the electric field strength by concentrating the electric field at the tip of the nozzle 301a due to the ultra-miniaturization of the nozzle 301a. Although it is possible to discharge droplets, it is desirable that induction by electrostatic force is performed between the nozzle 301a and the counter electrode 4. It is also possible to release the charge of the charged droplets by grounding the counter electrode 4.

  FIG. 6 is a schematic view showing the operation of discharging the fine liquid droplets of the liquid discharge apparatus shown in FIG. FIG. 5A is a schematic diagram illustrating a state in which a solution is supplied to the flow path in the nozzle of the liquid ejection device. FIG. 5B is a schematic view showing a state in which micro droplets are ejected from the nozzle of the liquid ejection device to the counter electrode side.

  FIG. 6 is a schematic view showing the operation of discharging the fine liquid droplets of the liquid discharge apparatus shown in FIG. FIG. 6A is a schematic diagram illustrating a state in which a solution is supplied to the flow path in the nozzle of the liquid ejection device. FIG. 6B is a schematic view showing a state in which micro droplets are ejected from the nozzle of the liquid ejection device to the counter electrode side.

  FIG. 6A will be described. The solution is supplied to the nozzle flow path 301a1 by a supply pump (not shown) of the solution supply means. In such a state, the discharge electrode 301b1 (see FIG. 4) is supplied by the bias power supply 301b2 (see FIG. 4). ) Through which a bias voltage is applied to the solution. In this state, the solution in the nozzle flow path 301a1 is charged, and a meniscus that is depressed in a concave shape by the solution is formed at the tip of the nozzle 301a. The vertical axis V represents the total voltage of the bias voltage and the pulse voltage, the horizontal axis T represents time, and the line in the graph represents the change over time of the total voltage during non-ejection.

  FIG. 6B will be described. When a pulse voltage is applied from the discharge voltage power supply 301b3, the solution is guided to the tip side of the nozzle 301a by the electrostatic force due to the electric field strength of the concentrated electric field at the tip portion of the nozzle 301a, and protrudes outside to the convex meniscus. Is formed, and the electric field is concentrated by the apex of the convex meniscus, and finally, a state in which micro droplets are discharged to the counter electrode side against the surface tension of the solution. The vertical axis V represents the total voltage of the bias voltage and the pulse voltage, the horizontal axis T represents time, and the line in the graph represents the change over time of the total voltage during ejection.

  Since the liquid ejection device 301 (see FIG. 4) ejects droplets by using an unprecedented minute diameter nozzle 301a, the electric field is concentrated by the charged solution in the nozzle flow path 31a1, and the electric field strength is increased. Therefore, it is possible to secure a more accurate droplet discharge property. For this reason, a nozzle having a structure in which electric field concentration is not performed (for example, an inner diameter of 100 μm) as in the prior art has been considered impossible to discharge because the voltage required for discharge becomes too high. Therefore, it is possible to discharge the solution at a lower voltage than in the prior art. And since it has a fine diameter, it is possible to easily control the discharge flow rate per unit time due to the low nozzle conductance, and the sufficiently small droplet diameter (not described above) without narrowing the pulse width. According to each condition, discharge of the solution by 0.8 μm) is realized. Furthermore, since the ejected droplets are charged, the vapor pressure is reduced even for very small droplets and the evaporation is suppressed, so the loss of droplet mass is reduced and the flight is stabilized. , Preventing a drop in droplet landing accuracy.

  In order to obtain an electrowetting effect on the nozzle 301a, an electrode may be provided on the outer periphery of the nozzle 301a, or an electrode may be provided on the inner surface of the nozzle flow path 301a1 and covered with an insulating film from above. . By applying a voltage to this electrode, the wettability of the inner surface of the nozzle flow path 301b1 can be increased by the electrowetting effect for the solution to which the voltage is applied by the ejection electrode 301b1, and the inside of the nozzle can be increased. The solution can be smoothly supplied to the flow path 301b1, and it is possible to discharge well and improve the response of the discharge.

  In addition, the discharge voltage application means 301b always applies a bias voltage and discharges a droplet by using a pulse voltage as a trigger, but always applies an alternating current or a continuous rectangular wave with an amplitude required for the discharge and increases and decreases its frequency. It is good also as a structure which discharges by switching. In order to discharge droplets, charging of the solution is indispensable. Even if a discharge voltage is applied at a frequency exceeding the charging speed of the solution, discharging is not performed, and the frequency is changed so that the solution can be sufficiently charged. Discharging is performed. Therefore, the discharge of the solution can be controlled by applying a discharge voltage at a frequency larger than the dischargeable frequency when discharging is not performed, and performing control to reduce the frequency to a dischargeable frequency band only when discharging is performed. Is possible. In such a case, since the potential applied to the solution itself does not change, it is possible to further improve the time response and thereby improve the droplet landing accuracy.

  In the present invention, a method of using the liquid discharge device 301 shown in FIG. 5 and discharging droplets from the nozzles as shown in FIG. 6 is called electrostatic suction nozzle discharge method.

  FIG. 7 is a schematic diagram showing a state in which an organic compound layer is formed by an ink jet method in a partition made by an electrostatic suction nozzle discharge method according to the present invention and a partition wall produced by a conventional ink jet method. FIG. 7A is a schematic view showing a state in which an organic compound layer is formed by an ink jet method in a partition made of a partition wall produced by a conventional ink jet method. FIG. 7B is a schematic view showing a state in which an organic compound layer is formed by an inkjet method in a partition made of partition walls produced by the electrostatic suction nozzle discharge method according to the present invention.

  A description will be given with reference to FIG. In the figure, reference numeral 102b 'denotes a partition wall produced by an ink jet method. Reference numeral 5 denotes a droplet. V ′ indicates the width of the partition wall 102b ′, and is usually 20 to 40 μm because of the size of the droplets in the ink jet method. W ′ indicates the height of the partition wall 102b ′. In this figure, it is 3 μm. X ′ indicates the width of the effective pixel electrode, and is 50 μm in this figure. In this figure, since the width of the partition is wide (the occupied area of the partition is large), there is no non-light emitting portion between the partition provided between the pixel electrodes 104b and the pixel electrode, and the light emitting layer formation area is set to the pixel. It can no longer be formed larger than the area. The droplets applied to the compartments become thicker on the partition wall side due to the difference in solvent drying speed between the central part and the end part of the droplets, and this influence extends to the area of the effective pixel electrode. The film thickness of the layer is not stable and varies in the effective pixel electrode region. Further, in order to cover the ejection accuracy of the ink jet method, a liquid repellent treatment of the partition walls is necessary.

  This will be described with reference to FIG. In the figure, reference numeral 102b denotes a partition wall produced by an electrostatic suction nozzle discharge method. Reference numeral 5 denotes a droplet. V indicates the width of the partition wall 102b, and is 5 to 20 μm from the relation of the size of the droplets in the electrostatic suction nozzle discharge method. W indicates the height of the partition wall 102b. In this figure, it is 3 μm. X represents the width of the effective pixel electrode, which is 50 μm, which is the same as the width of the effective pixel electrode shown in FIG. In this figure, since the width of the partition wall is narrow (the occupied area of the partition wall is small), a non-light-emitting portion can be taken between the partition wall provided between the pixel electrodes 104b and the pixel electrode. It can be formed larger than the pixel area. The droplet applied to the compartment becomes thicker on the partition wall due to the difference in solvent drying speed between the center and the edge of the droplet, but this effect does not reach the area of the effective pixel electrode, so it is applied to the compartment. In addition, a stable coating film is formed without the thickness of the organic compound layer being varied in the region of the effective pixel electrode. Further, since the film forming region can be enlarged, the ejection accuracy of the ink jet method can be covered, and the liquid repellent treatment of the partition walls can be made unnecessary.

The following effects can be obtained by fabricating the partition wall constituting the active organic EL element as shown in FIG. 2 by the electrostatic suction nozzle ejection method using the liquid ejection device as shown in FIGS. It is done.
1) It has become possible to produce a partition wall with higher precision and narrow width, which has been difficult to produce with conventional inkjet ejection accuracy.
2) By narrowing the width of the partition wall with high accuracy, the area occupied by the partition wall can be reduced, so that the light emitting layer formation area can be formed larger than the pixel area, so the film thickness of the organic compound layer in the partition wall Unevenness can be reduced.
3) Since the area of the light-emitting layer can be formed larger than the pixel area by reducing the area occupied by the partition by reducing the width of the partition with high accuracy, the organic compound layer in the partition is formed by an inkjet method. It has become possible to form with the discharge accuracy of a conventional droplet discharge method such as a dispenser method.
4) Since direct patterning with high positional accuracy is possible, the material cost can be reduced, and the conventional photolithography can be eliminated, so that the equipment cost can be reduced and the production cost can be reduced. Become.
5) Due to the effects shown in 1) to 4), it is possible to produce a low-cost, high-quality organic EL element, and it is possible to apply it to a spontaneous emission type display device replacing a liquid crystal display.

  The partition material solution according to the present invention is a solution obtained by dissolving a partition material in water or an organic solvent. Examples of the partition material according to the present invention include polymers such as epoxy resins, acrylic resins, polyimide resins, olefin resins, phenol resins, melamine resins, urethane resins, polyester resins, and polyvinyl resins. It is possible to use materials. However, when it is necessary to perform heat treatment, it is preferable to have a heat resistance of 250 ° C. or higher, and in this respect, epoxy resins, acrylic resins, and polyimide resins are preferable.

  The partition wall material is diluted or dispersed to an appropriate concentration in a solvent such as toluene, xylene, methylene chloride, water, etc., and then droplets of ultrafine and fine diameters are discharged from the electrostatic suction nozzle discharge device shown in FIGS. The partition walls corresponding to the pixel electrodes formed by patterning are formed by forming the partition walls in the vertical direction and the horizontal direction. Furthermore, the partition wall material solution is preferably a solution that cures when heat is applied.

  Hereinafter, the gas barrier layer, the first electrode, the hole transport layer, the light emitting layer, the electron transport layer, the second electrode, the sealing layer and the like constituting the organic EL device according to the present invention will be described.

  A transparent resin film is mentioned as a strip | belt-shaped flexible support body used for the strip | belt-shaped flexible support body in which the gas barrier layer concerning this invention and the 1st electrode were already formed. Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloolefin resins such as polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Is mentioned.

A gas barrier film is preferably formed on the surface of the resin film used as the belt-like flexible support, if necessary. Examples of the gas barrier film include an inorganic film, an organic film, or a hybrid film of both. As a characteristic of the gas barrier film, the water vapor permeability is preferably 0.01 g / m ² · day · atm or less. Furthermore, the oxygen permeability is 10 ⁻³ ml /
It is preferably a high barrier film having a m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less.

As a material for forming the barrier film, any material may be used as long as it has a function of suppressing intrusion of elements such as moisture and oxygen that cause deterioration of the element. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times. The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, the sputtering method, the reactive sputtering method, the molecular beam epitaxy method, the cluster ion beam method, the ion plating method, the plasma polymerization method, the atmospheric pressure plasma weighting. A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

As the first electrode, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, CuI, indium tin oxide (ITO), SnO ₂ , Zn
Examples thereof include conductive transparent materials such as O. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ .ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern of a desired shape may be formed by photolithography, or if the pattern accuracy is not so high (about 100 μm or more) ), A pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. Or when using the substance which can be apply | coated like an organic electroconductive compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is taken out from the anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

  A hole injection layer (anode buffer layer) may be present between the first electrode and the light emitting layer or the hole transport layer. The hole injection layer is a layer provided between the electrode and the organic layer in order to lower the driving voltage and improve the luminance of light emission. “The organic EL element and the forefront of industrialization (November 30, 1998, NTS) The details are described in the second volume, Chapter 2, “Electrode Materials” (pages 123 to 166) of “The Company”. The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers. The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound. Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-
p-tolylaminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N′-diphenyl-N , N'-di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) ) Quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbenzene; N-phenylcarbazole Further, those having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule, for example, 4,4′-bis [N- (1-naphthyl) -N -Phenylamino] biphenyl (NPD), 4,4 ′, 4 ″ -tris [N- (3- (3) in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type. Methylphenyl) -N-phenylamino] triphenylamine (MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

  Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. This hole transport layer may have a single layer structure composed of one or more of the above materials. A hole transport layer having a high p property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like. It is preferable to use such a hole transport layer having a high p property because an organic EL element with lower power consumption can be produced.

  In the present invention, the light emitting layer refers to a blue light emitting layer, a green light emitting layer, and a red light emitting layer. There is no restriction | limiting in particular as a lamination order in the case of laminating | stacking a light emitting layer, You may have a nonluminous intermediate | middle layer between each light emitting layer. In the present invention, it is preferable that at least one blue light emitting layer is provided at a position closest to the anode in all the light emitting layers. Also, when four or more light emitting layers are provided, for example, blue light emitting layer / green light emitting layer / red light emitting layer / blue light emitting layer, blue light emitting layer / green light emitting layer / red light emitting layer / blue light emitting from the order close to the anode. Layered / green light emitting layer, blue light emitting layer / green light emitting layer / red light emitting layer / blue light emitting layer / green light emitting layer / red light emitting layer, etc. It is preferable for improving luminance stability. A white element can be manufactured by forming a light emitting layer in multiple layers.

  The total thickness of the light emitting layer is not particularly limited, but is usually selected in the range of 2 nm to 5 μm, preferably 2 to 200 nm in consideration of the uniformity of the film and the voltage required for light emission. Furthermore, it is preferable that it exists in the range of 10-20 nm. A film thickness of 20 nm or less is preferable because it has the effect of improving the stability of the emission color with respect to the driving current as well as the voltage surface. The film thickness of each light emitting layer is preferably selected in the range of 2 to 100 nm, and more preferably in the range of 2 to 20 nm. Although there is no restriction | limiting in particular about the film thickness relationship of each light emitting layer of blue, green, and red, It is preferable that the blue light emitting layer (the sum total when there are multiple layers) is the thickest among three light emitting layers.

  The light emitting layer includes at least three layers having different emission spectra, each having an emission maximum wavelength in the range of 430 to 480 nm, 510 to 550 nm, and 600 to 640 nm. If it is three or more layers, there will be no restriction | limiting in particular. When there are more than four layers, there may be a plurality of layers having the same emission spectrum. A layer having an emission maximum wavelength in the range of 430 to 480 nm is referred to as a blue light emitting layer, a layer in the range of 510 to 550 nm is referred to as a green light emitting layer, and a layer in the range of 600 to 640 nm is referred to as a red light emitting layer. Moreover, in the range which maintains the said maximum wavelength, you may mix a several luminescent compound in each light emitting layer. For example, the blue light emitting layer may be used by mixing a blue light emitting compound having a maximum wavelength of 430 to 480 nm and a green light emitting compound having the same wavelength of 510 to 550 nm.

  The material used for the light emitting layer is not particularly limited, and examples thereof include the latest trends of Toray Research Center, Inc. flat panel displays, the current state of EL displays and the latest technological trends, and various materials as described on pages 228-332.

  The light emitting layer formed by applying the coating liquid for forming the light emitting layer with the second wet coater 206b and drying is recombined with the electrons and holes injected from the electrode or the electron injection layer and the hole transport layer. The light emitting portion may be in the light emitting layer or at the interface between the light emitting layer and the adjacent layer.

The hole transport layer forming coating solution and the light emitting layer forming coating solution to be used have at least one organic compound material and at least one solvent, taking into account repelling during coating, coating unevenness, and the like. The surface tension is preferably 15 × 10 ^{−3 to} 55 × 10 ⁻³ N / m.

  The process of forming the hole transport layer and the light emitting layer, which are the constituent layers of the organic EL element shown in this figure, considers the maintenance of the performance of the hole transport layer and the light emitting layer, the prevention of failure defects due to foreign matter adhesion, etc. It is preferable that the dew point is −20 ° C. or lower and the measured cleanliness is class 5 or lower, and the atmospheric pressure is 10 to 45 ° C. excluding the drying section. In the present invention, cleanliness of class 5 or less means class 3 to class 5.

  The electron injection layer is made of a material having a function of transporting electrons and is included in the electron transport layer in a broad sense. The electron injection layer is a layer provided between the electrode and the organic layer for lowering the driving voltage and improving the luminance of the light emission. “Organic EL element and its forefront of industrialization (NST 30, November 30, 1998) Issue) ”, Chapter 2, Chapter 2,“ Electrode Materials ”(pages 123-166). The details of the electron injection layer (cathode buffer layer) are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

  In addition, as an electron transport material (also serving as a hole blocking material) used for the electron transport layer adjacent to the light emitting layer side, it is sufficient if it has a function of transmitting electrons injected from the cathode to the light emitting layer. As a material, any one of conventionally known compounds can be selected and used. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodisides. Examples include methane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivatives, thiadiazole derivatives in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and quinoxaline derivatives having a quinoxaline ring known as an electron-withdrawing group can also be used as the electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Also, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metal of these metal complexes is In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. Distyrylpyrazine derivatives can also be used as electron transport materials, and inorganic semiconductors such as n-type-Si and n-type-SiC are also used as electron transport materials in the same manner as the hole injection layer and hole transport layer. I can do it. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

An electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. , 9
5, 5773 (2004). It is preferable to use such an electron transport layer having a high n property because an element with lower power consumption can be manufactured. The electron transport layer can also be formed by thinning the electron transport material by a known method such as wet coating or vacuum deposition.

As the second electrode, a material having a work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the first electrode (anode) or the second electrode (cathode) of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.

  Moreover, after producing the metal with a thickness of 1 to 20 nm on the second electrode, the conductive transparent material mentioned in the description of the first electrode is produced thereon, so that a transparent or translucent second electrode ( A cathode) can be manufactured, and by applying this, an element in which both the first electrode (anode) and the second electrode (cathode) are transmissive can be manufactured.

  The light emitting layer constituting the organic EL device of the present invention contains a known host compound and a known phosphorescent compound (also referred to as a phosphorescent compound) in order to increase the luminous efficiency of the light emitting layer. Is preferred.

  The host compound is a compound contained in the light-emitting layer, the mass ratio in the layer is 20% or more, and the phosphorescence quantum yield of phosphorescence emission is 0.1 at room temperature (25 ° C.). Is defined as less than a compound. The phosphorescence quantum yield is preferably less than 0.01. A plurality of host compounds may be used in combination. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. In addition, by using a plurality of phosphorescent compounds, it is possible to mix different light emission, thereby obtaining an arbitrary emission color. White light emission is possible by adjusting the kind of phosphorescent compound and the amount of doping, and can also be applied to illumination and backlight.

  As these host compounds, compounds having a hole transporting ability and an electron transporting ability, preventing emission light from being increased in wavelength, and having a high Tg (glass transition temperature) are preferable. Known host compounds include, for example, JP-A Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, and 2002-334786. Gazette, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645 2002-338579, 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227 2002-231453, 2003-3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, Examples thereof include compounds described in 2002-299060, 2002-302516, 2002-305083, 2002-305084, 2002-308837 and the like.

  In the case of having a plurality of light emitting layers, it is preferable that 50% by mass or more of the host compound in each layer is the same compound because it is easy to obtain a uniform film property over the entire organic layer. It is more preferable that the light emission energy is 2.9 eV or more because it is advantageous in efficiently suppressing energy transfer from the dopant and obtaining high luminance. Phosphorescence emission energy means the peak energy of the 0-0 band of phosphorescence emission when the photoluminescence of a deposited film of 100 nm is measured on a substrate with a host compound.

  The host compound has a phosphorescence emission energy of 2.9 eV or more and a Tg of 90 ° C. or more in consideration of deterioration of the organic EL device over time (decrease in luminance and film properties), market needs as a light source, and the like. Preferably there is. That is, in order to satisfy both luminance and durability, it is preferable that phosphorescence emission energy is 2.9 eV or more and Tg is 90 ° C. or more. Tg is more preferably 100 ° C. or higher.

A phosphorescent compound (phosphorescent compound) is a compound in which light emission from an excited triplet is observed, is a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 25. ℃
The compound is 0.01 or more. When used in combination with the host compound described above, an organic EL device with higher luminous efficiency can be obtained.

  The phosphorescent compound according to the present invention preferably has a phosphorescence quantum yield of 0.1 or more. The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen), 4th edition, Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence quantum yield used in the present invention only needs to achieve the phosphorescence quantum yield in any solvent.

  There are two types of light emission of the phosphorescent compound in principle. One is the recombination of the carrier on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent compound. The energy transfer type is to obtain light emission from the phosphorescent compound by moving to the other, and the other is that the phosphorescent compound becomes a carrier trap, and carrier recombination occurs on the phosphorescent compound, and the phosphorescent compound emits light. Although it is a carrier trap type in which light emission can be obtained, in any case, it is a condition that the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

  The phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of the organic EL device. The phosphorescent compound is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound), rare earth Of these, iridium compounds are the most preferred.

  In the present invention, the phosphorescence emission maximum wavelength of the phosphorescent compound is not particularly limited, and can be obtained in principle by selecting a central metal, a ligand, a ligand substituent, and the like. The emission wavelength can be changed.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

The white element referred to in the present invention means that the chromaticity in the CIE1931 color system at 1000 cd / m ² is X = 0.33 ± 0.
07, Y = 0.33 ± 0.07.

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor may be used in combination. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

The organic EL device of the present invention preferably uses the following method in combination in order to efficiently extract light generated in the light emitting layer. The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1), and only about 15% to 20% of the light generated in the light emitting layer can be extracted. It is generally said that there is no. This is because the light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the element, or the transparent electrode or light emitting layer and the transparent substrate This is because the light undergoes total reflection between them, the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the side surface of the device.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435). A method for improving efficiency by providing a substrate with a light condensing property (JP-A-63-314795). A method of forming a reflective surface on the side surface of an element (Japanese Patent Laid-Open No. 1-220394). A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between a substrate and a light emitter (Japanese Patent Laid-Open No. 62-172691). A method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter (Japanese Patent Laid-Open No. 2001-202827). There is a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer, and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951).

  In the present invention, these methods can be used in combination with an organic EL element. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, a transparent electrode layer, A method of forming a diffraction grating between any layers of the light emitting layer (including between the substrate and the outside) can be suitably used. In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a low refractive index medium is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower. . Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less. The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate. The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method is generated from the light emitting layer by utilizing the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Of the light, the light that cannot go out due to total reflection between layers, etc. is diffracted by introducing a diffraction grating into any layer or medium (inside a transparent substrate or transparent electrode) , Trying to extract light out. The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. The light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction grating is preferably two-dimensionally repeated such as a square lattice, a triangular lattice, or a honeycomb lattice.

Furthermore, the organic EL device of the present invention is processed so as to provide, for example, a structure on the microlens array on the light extraction side of the substrate in order to efficiently extract light generated in the light emitting layer, or so-called condensing. By combining with the sheet, the luminance in the specific direction can be increased by collecting light in a specific direction, for example, in the front direction with respect to the element light emitting surface. As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, a substrate may be formed with a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or the apex angle is rounded and the pitch is changed randomly. Other shapes may be used. Moreover, in order to control the light emission angle from a light emitting element, you may use a light-diffusion plate and a film together with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

  Hereinafter, although an example is given and the concrete effect of the present invention is shown, the mode of the present invention is not limited to this.

Example 1
<Preparation of strip-shaped flexible substrate>
A polyethylene terephthalate film having a thickness of 100 μm (a film made by Teijin-Deupon Corp., hereinafter abbreviated as PET) was prepared.

(Formation of a transparent gas barrier layer)
On the prepared PET, a transparent gas barrier layer having a thickness of about 90 nm was formed by an atmospheric pressure plasma discharge treatment method. As a result of measuring the water vapor transmission rate by a method based on JISk-7129B, it was 10 ⁻³ g / m ² / day or less. As a result of measuring the oxygen transmission rate by a method based on JISk-7126B, it was 10 ⁻³ g / m ² / day or less.

(Formation of the first electrode)
On the barrier layer thus formed, ITO (indium tin oxide) having a thickness of 120 nm was patterned by a vapor deposition method to form a first electrode.

(Preparation of coating solution for hole transport layer)
Polyethylene dioxythiophene / polystyrene sulfonate (PEDOT / PSS, Baytron P AI 4083 manufactured by Bayer) was diluted to 65% with pure water and 5% with methanol to obtain a coating solution for a hole transport layer.

(Formation of hole transport layer)
The substrate on which the first electrode was formed was subjected to cleaning surface modification treatment and charge removal treatment, and then a hole transport layer coating solution was applied by a wet coating method, followed by solvent removal treatment and heat treatment to form a hole transport layer. . The conveyance speed was 0.5 m / min. In order to remove organic contaminants on the substrate on which the first electrode was formed and improve wettability, a surface modification treatment was performed at a low pressure mercury lamp wavelength of 184.9 nm, an irradiation intensity of 15 mW / cm ² , and an irradiation distance of 10 mm.
In order to prevent dust from adhering to the substrate on which the first electrode was formed and dielectric breakdown, a charge removal process was performed using a static eliminator using weak X-rays.

As a wet coating method, a film was formed by a cap coat method in a box in an inert gas atmosphere so that the dry film thickness of the coating solution shown above was 50 nm. A positive hole transport layer was formed by using a vacuum drying furnace as a solvent removal heat treatment step and placing it under conditions of 133 Pa and 100 ° C. for 60 minutes.
(Preparation of partition wall forming solution)
A coating solution having the following components was prepared.
(Composition of partition wall coating solution)
Polyimide solution (trade name Iupicoat FS-100L, manufactured by Ube Industries) 90 parts by mass Methyl isobutyl ketone (MIBK) 10 parts by mass The viscosity is 20 Pa · s at 25 ° C., and the solid content concentration is 40%.
(Formation of partition walls)
After the substrate having the plurality of first electrodes (pixel electrodes) formed by patterning is subjected to an electroremoval process, the X axis and Y provided on the substrate mounting table are placed on the substrate mounting table as shown in FIG. It was placed according to the axial index. After that, on the hole transport layer corresponding to the space between the plurality of first electrodes (pixel electrodes) patterned and formed by the electrostatic suction nozzle discharge method using the liquid discharge apparatus shown in FIG. As shown in Table 1, after changing the width of the barrier ribs so that the dry film thickness is 3 μm, the barrier ribs are scanned and drawn using a vacuum drying furnace similar to that of the hole transport layer under conditions of 133 Pa and 120 ° C. For 90 minutes, a solvent removal heat treatment was performed, and a substrate with a partition wall having a partition wall width was prepared. 1-1 to 1-6. In preparing the partition walls shown in Table 1, the nozzle inner diameter, the discharge droplet amount, and the number of scans in the used liquid discharge apparatus are appropriately set according to the width of each partition and are shown in Table 1.

  The width of the partition wall in the horizontal direction and the vertical direction was the same. The area per pixel including the non-pixel area is 100 μm square, the pixel electrode area partitioned by the partition is 85 μm square, and the non-pixel area between the pixel electrodes is 30 μm in both the vertical and horizontal directions. The distance from the tip of the nozzle to the surface of the substrate on which the liquid droplets landed was 300 μm.

  The width of the partition wall shows a result of measurement using a laser microscope manufactured by Keyence Corporation, which is provided substantially perpendicular to the droplet receiving surface of the substrate. The volume of the droplet is the equivalent diameter obtained by shooting the droplet ejected from the nozzle and flying using an ultra high-speed camera, treating the droplet as a sphere, processing the two-dimensional image, and converting the area of the droplet into a circle. And calculated from the obtained diameter.

(Production of organic EL element)
Prepared substrate with partition No. After performing the charge removal treatment on 1-1 to 1-6, a light emitting layer, an electron transport layer, a cathode, and a sealing film are sequentially formed on the hole transport layer surrounded by the partition wall by the following method, and organic An EL element was fabricated and sample No. 101-106.
(Formation of light emitting layer)
The dopant material Ir (ppy) ₃ is 5% by mass with respect to the host material polyvinyl carbazole (PVK) 1.2. Using a droplet discharge method, a light emitting layer was formed to a thickness of 100 nm after drying a solution for a light emitting layer, which was a 10% solution dissolved in dichloroethane. Subsequently, using a vacuum drying furnace similar to that for the hole transport layer, a solvent removing heat treatment was carried out by placing it at 133 Pa and 100 ° C. for 30 minutes. After the heat treatment, the substrate is cooled to the same temperature as the room temperature, and similarly, the red dopant material Btp ₂ Ir (acac) is 10% by mass so that it becomes 10% by mass. Dissolved in dichloroethane to give a 10% by mass solution, so that the blue dopant material FIr (pic) is 3% by mass. Those dissolved in dichloroethane to give a 3% by mass solution were each formed by a droplet discharge method and subjected to a drying heat treatment. An ink jet method was used as a droplet discharge method.

(Formation of electron transport layer)
A 0.5-nm-thick LiF layer was vapor-deposited in the region of the light-emitting layer formed under a vacuum of 5 × 10 ⁻⁴ Pa to form an electron transport layer.

(Formation of cathode)
An electrode was formed by vapor-depositing an aluminum layer having a thickness of 100 nm on the electron transport layer formed under a vacuum of 5 × 10 ⁻⁴ Pa.

(Formation of sealing film)
On the electrode formed under a vacuum of 5 × 10 ⁻⁴ Pa, SiOx was vapor-deposited with a thickness of 300 nm by a sputtering method in a region other than the region serving as the connection terminal, thereby forming a sealing film.

(Evaluation)
Each prepared sample No. Table 2 shows the results of the evaluation of productivity and light emission unevenness according to the following test methods attached to 101 to 106 and evaluated according to the evaluation rank shown below.

Evaluation Method for Productivity Evaluation was performed based on the number of scans with respect to the substrate of the electrostatic suction nozzle ejection device required to satisfy a predetermined film thickness when the partition wall was formed.

◎: Number of scans less than 20 times ○: Number of scans from 20 times to less than 200 times △: Number of scans from 200 times to less than 1000 times ×: Test method for uneven light emission KEITLEY source measure unit A DC voltage was applied to the organic EL element to emit light using the Model 2400. With respect to the light-emitting element that emitted light at 200 cd, light emission unevenness was observed with a 50 × microscope.

Evaluation rank of light emission unevenness ◎: 90% or more emit light uniformly ○: 80% or more emit light uniformly △: 70% or more emit light uniformly ×: Less than 70% emit light uniformly Not

  Sample No. With 101 exceeding the preferable partition wall width of 5 to 20 μm, the film formation area with respect to the effective pixel area could not be increased, resulting in uneven light emission. Sample No. No. 106 has problems such as production complexity of the fine nozzle, a decrease in productivity due to an increase in the number of scans to satisfy a desired film thickness, and a landing pattern disorder (large deviation from the set partition wall width) due to an increase in the number of scans. is there. The effectiveness of the present invention was confirmed.

Example 2
<Preparation of substrate>
A glass substrate having TFTs arranged in a pattern on a 700 μm thick soda lime glass (Asahi Glass Co., Ltd.) substrate was prepared.

(Formation of the first electrode)
A first electrode was formed by patterning ITO (indium tin oxide) having a thickness of 120 nm by a vapor deposition method using a mask matched to the TFTs arranged in a pattern.

(Formation of hole transport layer)
The same hole transport layer coating solution as that used in Example 1 was used, and a hole transport layer was formed on the first electrode in the same manner as in Example 1.

(Formation of partition walls)
A hole transport layer corresponding to a plurality of first electrodes (pixel electrodes) formed by patterning and forming the same partition wall forming coating solution as the partition wall forming coating solution used in Example 1, and by the same method as in the example. A partition wall substrate having a partition wall width and having a partition wall width was prepared. 2-1 to 2-6.
(Production of organic EL element)
Prepared substrate with partition No. After performing the charge removal treatment on 2-1 to 2-6, the same material as in Example 1 is used on the hole transport layer surrounded by the partition walls, and the light emitting layer and the electron transport layer are formed in the same manner as in Example 1. , A cathode, and a sealing film are sequentially formed to produce an organic EL element. 201-206.

(Evaluation)
Each prepared sample No. Table 3 shows the results of evaluating productivity and light emission unevenness according to the same test method as in Example 1 and evaluating according to the same evaluation rank as in Example 1.

  The effectiveness of the present invention was confirmed.

It is a schematic flowchart which manufactures an organic EL element. It is a partial schematic diagram of an active organic EL element. It is a schematic plan view which shows the state of the grid | lattice-like partition formed in the form surrounding the several pixel electrode formed on the board | substrate. It is a schematic diagram of the electrostatic suction nozzle discharge method apparatus which forms the grid | lattice-like partition shown by FIG. FIG. 5 is an enlarged schematic cross-sectional view of the liquid ejection device along BB ′ in FIG. 4. FIG. 6 is a schematic diagram illustrating a discharge operation of micro droplets of the liquid discharge apparatus illustrated in FIG. 5. It is a schematic diagram which shows the state which forms the organic compound layer by the inkjet method in the division made by the electrostatic suction nozzle discharge method concerning this invention, and the partition produced by the conventional inkjet method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic EL element 101 Section 102a, 102b, 102b 'Partition 103, 2 Substrate 104 Pixel electrode 104a TFT
104b ITO electrode (anode)
105a Hole transport layer 105b Light emitting layer 3 Electrostatic suction nozzle ejection device 301 Liquid ejection device 301a Nozzle 301a1 Flow path 301a2 Liquid droplet 301b Discharge voltage application means 301c1 Nozzle plate 302 Substrate mounting table 303 Curing means 4 Counter electrodes R, S Width T , U interval

Claims (9)

An organic electroluminescence device having an organic compound layer including at least one light emitting layer and a second electrode on a pixel electrode partitioned by a plurality of grid-like partition walls formed on a substrate; and a pixel electrode forming step; In the method for manufacturing an organic electroluminescence element manufactured by a manufacturing apparatus having a partition wall forming step, an organic compound layer forming step, and a second electrode forming step,
Between the pixel electrode forming step and the partition wall forming step , a surface cleaning process, a surface modification process and a charge removal process are performed on the substrate, and the partition wall is formed by an electrostatic suction nozzle discharge method,
The method of manufacturing an organic electroluminescence element, wherein the light emitting layer is formed on the pixel electrode by a droplet discharge method in the organic compound layer forming step. The method for manufacturing an organic electroluminescent element according to claim 1, wherein the partition wall has a width of 5 to 20 μm. 3. The organic electroluminescent element according to claim 1, wherein a volume per droplet of the partition wall material solution discharged by the electrostatic suction nozzle discharge method is 0.05 to 1 pl (picoliter). Production method. 4. The method of manufacturing an organic electroluminescence element according to claim 1, wherein a nozzle diameter (inner diameter) of a discharge nozzle used in the electrostatic suction nozzle discharge method is 3 to 10 μm. . The method of manufacturing an organic electroluminescence element according to claim 1, wherein the substrate is a flexible substrate. The organic compound layer forming step forms the other organic compound layers excluding the light emitting layer by any one of a vacuum deposition method, a wet film formation method, and a droplet discharge method. The manufacturing method of the organic electroluminescent element of any one of these. The said light emitting layer has a phosphorescent compound, The manufacturing method of the organic electroluminescent element in any one of Claims 1-6 characterized by the above-mentioned. An organic electroluminescent device manufactured by the method for manufacturing an organic electroluminescent device according to claim 1. An organic electroluminescence device using the organic electroluminescence element produced by the method for producing an organic electroluminescence element according to any one of claims 1 to 7.

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