JP2008243650A - Organic electroluminescent device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL device wherein heat generated in an organic EL element can be efficiently released by improving a structure on the element substrate side. <P>SOLUTION: In the element substrate 10 of the organic EL device 1, a heat dissipating layer 8 having thermal conductivity higher than that of a barrier rib 5 is formed in both end parts 100e, 100f in the longitudinal direction of a pixel region 100, and the heat dissipating layer 8 projects upward from the upper end face of the barrier rib 5. In addition, a part of an negative electrode layer 12 is superposed on the upper end face of the heat dissipating layer 8. Therefore, heat generated in an organic functional layer 20 can be efficiently released through a sealing substrate 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence device (hereinafter, “electroluminescence” is referred to as “EL”) having an organic functional layer in a region surrounded by a partition wall.

  As shown in FIGS. 10A and 10B, the organic EL device includes a pixel electrode 11 (anode) in the pixel region 100 surrounded by the partition wall 5 on the element substrate 10 as shown in the entire cross section and the cross section of the pixel region. Layer), an organic functional layer 20 including a hole injecting and transporting layer 21 and a light emitting layer 22, and a cathode layer 12 are sequentially stacked. The organic functional layer 20 is formed, for example, by discharging a liquid composition in which an organic fluorescent material or the like is dissolved and dispersed in a solvent (including a dispersion medium) onto the element substrate 10 by an ink jet method and then solidifying the liquid composition. No. 5 functions as a bank that prevents the liquid composition from protruding from a predetermined region when the liquid composition is discharged. In addition, a sealing substrate 9 is disposed opposite to the surface of the element substrate 10 on which the organic EL element 2 is formed, and the sealing substrate 9 and the element substrate 10 are sealed on the entire surface or the outer peripheral side. Bonded with resin 90.

In the organic EL device configured as described above, heat is generated when the organic EL element 2 is driven. Therefore, in order to improve the reliability of the organic EL device, it is necessary to efficiently release the heat generated in the organic EL element 2. Therefore, a structure using a sealing member with high thermal conductivity and a structure with two sealing substrates are proposed (see Patent Documents 1 and 2).
JP 2004-119277 A JP 2005-317346 A

  However, in the organic EL device, even if the thermal conductivity of the sealing member is increased, the heat conduction on the way from the organic EL element 2 to the sealing material is low, so that the heat generated in the organic EL element 2 is efficiently released. There is a problem that can not be.

  In view of the above problems, an object of the present invention is to provide an organic EL device that can efficiently release heat generated in an organic EL element by improving the structure on the element substrate side.

  In order to solve the above problems, in the present invention, an organic EL in which a first electrode layer, an organic functional layer including at least a light emitting layer, and a second electrode layer are sequentially stacked in a pixel region surrounded by a partition wall. In an organic EL device including an element substrate on which an element is formed, heat dissipation that is higher in thermal conductivity than the partition is partly on the organic functional layer on a lower layer side of the second electrode layer in the pixel region. It is characterized in that the layers are laminated.

  In the present invention, the heat generated in the organic functional layer is first dissipated through the second electrode layer. However, the portion of the second electrode layer that is in contact with the organic functional layer is on the inner side of the partition wall, and is at a position lower than the partition wall unless the thickness is very large. Therefore, the temperature rise of the organic EL element cannot be sufficiently suppressed only by heat radiation from the portion of the second electrode layer that is in contact with the organic functional layer. However, in the present invention, on the lower layer side of the second electrode layer in the pixel region, a heat dissipation layer having higher thermal conductivity than the partition is directly laminated on a part of the organic functional layer. The organic EL element is positioned above the portion of the second electrode layer that is in contact with the organic functional layer in a state where it is in contact with the most functional organic functional layer. Therefore, the heat generated in the organic functional layer is efficiently radiated through the heat radiating layer. Therefore, since the temperature rise of the organic EL element can be kept low, the reliability of the organic EL device can be improved.

  In the present invention, it is preferable that the heat dissipation layer is formed at an end portion in the pixel region. In the pixel area, the central area is often used as an effective light emitting area. Therefore, if a heat dissipation layer is disposed in an area that avoids the effective light emitting area, heat is emitted without reducing the amount of light emitted from the organic EL element. A layer can be provided.

  In the present invention, the heat-dissipating layer is composed of a clay mineral such as talc, mica, and sericite, a resin containing a filler such as titanium oxide, barium sulfate, and carbon black, or an inorganic insulating material such as silicon oxide or silicon nitride. It is composed of materials. If a filler is blended with the resin, the thermal conductivity of the resin can be increased, and if it is a resin, it is suitable for forming a thick heat dissipation layer. Moreover, if it is an inorganic insulating material, it can comprise a thermal radiation layer with high heat conductivity compared with resin.

  In this invention, it is preferable that a part of said 2nd electrode layer has overlapped with the upper end surface of the said thermal radiation layer. If comprised in this way, since the part which overlaps with the upper end surface of the said heat radiating layer among the 2nd electrode layers exists in a position higher than the part which has overlapped with the organic functional layer directly, heat dissipation is high. Therefore, since the temperature rise of the organic EL element can be kept low, the reliability of the organic EL device can be improved.

  In this invention, it is preferable that the said heat radiating layer protrudes upwards from the upper end surface of the said partition. If comprised in this way, since the heat dissipation from a thermal radiation layer will improve, the temperature rise of an organic EL element can be restrained low, and the reliability of an organic EL apparatus can be improved.

  In the present invention, a sealing substrate is disposed opposite to a surface of the element substrate on which the organic EL element is formed, and the sealing substrate is bonded to the element substrate with a sealing resin. Can be adopted. With this configuration, the heat generated in the organic functional layer can be released to the sealing substrate through the heat dissipation layer and the second electrode layer, so that the temperature rise of the organic EL element can be suppressed to a low level. The reliability of the EL device can be improved.

  In this case, it is preferable that the sealing resin is also disposed in a region overlapping with the pixel region. When the sealing resin is interposed between the pixel region and the sealing substrate, the heat generated in the organic functional layer is reduced as compared with the case where only an inert gas such as nitrogen gas is interposed. It is possible to efficiently escape to the sealing substrate through the two electrode layers.

  In the present invention, in the sealing resin, it is preferable that a resin portion disposed at least in a portion where the heat dissipation layer is formed in the pixel region includes a filler. If comprised in this way, the heat | fever which generate | occur | produced in the organic functional layer can be efficiently escaped to the sealing substrate through the resin part containing a thermal radiation layer, a 2nd electrode layer, and a filler.

  When the organic EL device according to the present invention is configured as a top emission type that emits light from the sealing substrate side, the sealing substrate is translucent, and in the sealing resin, in the pixel region, A translucent resin material is used at least for the resin portion disposed in the region where the heat dissipation layer is not formed.

  In the present invention, when the surface of the element substrate on which the organic EL element is formed is bonded to a sealing substrate, the portion of the element substrate where the heat dissipation layer is formed is the sealing substrate. It is preferable to touch. If comprised in this way, the heat | fever generate | occur | produced in the organic functional layer can be efficiently escaped by heat conduction to a sealing substrate via a thermal radiation layer and a 2nd electrode layer.

  In this case, in the sealing substrate, a recess is formed in a portion overlapping the portion where the heat dissipation layer is formed, and an upper end portion of the portion where the heat dissipation layer is formed in the element substrate is located in the recess. It is preferable. If comprised in this way, since the contact area of the part in which the thermal radiation layer is formed, and a sealing substrate becomes large, the heat | fever which generate | occur | produced in the organic functional layer is sealed via a thermal radiation layer and a 2nd electrode layer. In addition, it can escape efficiently by heat conduction.

  In the present invention, the organic functional layer can be formed by solidifying a liquid composition disposed in the pixel region. That is, in the method of manufacturing an organic EL device to which the present invention is applied, after forming at least the pixel electrode and the partition, and before forming the organic functional layer and the cathode, liquid is applied to the pixel region surrounded by the partition. After the composition is disposed, the organic functional layer is formed by performing a solidifying step.

  The organic EL device according to the present invention is used in an electronic apparatus such as a line head of an image forming apparatus such as a copying machine or a display device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings used for the following description, the scale of each layer and each member is shown to be different from the actual one in order to make each member large enough to be recognized on the drawing.

[Embodiment 1]
(Electrical configuration)
FIG. 1 is a block diagram showing an electrical configuration of an active matrix type organic EL display device as an example of an organic EL device to which the present invention is applied. The organic EL device 1 shown in FIG. 1 includes a plurality of scanning lines 101, a plurality of signal lines 102 extending in a direction intersecting the scanning lines 101, and a plurality of power supply lines 103 extending in parallel to the signal lines 102. In addition to having a wired configuration, a pixel region 100 described later is provided near each intersection of the scanning line 101 and the signal line 102. A data side driving circuit 104 including a shift register, a level shifter, a video line, and an analog switch is connected to the signal line 102, and a scanning side driving circuit 105 including a shift register and a level shifter is connected to the scanning line 101. Each pixel region 100 holds a switching thin film transistor 112 to which a scanning signal is supplied to the gate electrode via the scanning line 101, and a pixel signal supplied from the signal line 102 via the switching thin film transistor 112. The storage capacitor 130, the driving thin film transistor 123 to which the pixel signal held by the storage capacitor 130 is supplied to the gate electrode, and the power source line 103 when electrically connected to the power source line 103 through the driving thin film transistor 123. A pixel electrode 11 (anode layer / first electrode layer) through which a drive current flows from the line 103, and an organic functional layer 20 sandwiched between the pixel electrode 11 and the cathode layer 12 (second electrode layer) Is provided. Here, the pixel electrode 11, the organic functional layer 20, and the cathode layer 12 constitute the organic EL element 2.

  According to such a configuration, when the scanning line 101 is driven and the switching thin film transistor 112 is turned on, the potential of the signal line 102 at that time is held in the holding capacitor 130, and the holding capacitor 130 is driven according to the state. The on / off state of the thin film transistor 123 is determined. Then, current flows from the power supply line 103 to the pixel electrode 11 through the channel of the driving thin film transistor 123, and further current flows to the cathode layer 12 through the organic functional layer 20. As a result, the organic EL element 2 emits light according to the amount of current flowing therethrough.

(Overall structure)
FIG. 2 is a longitudinal sectional view showing the overall configuration of the organic EL device 1 according to Embodiment 1 of the present invention. As shown in FIG. 2, the organic EL device 1 according to this embodiment includes a pixel electrode 11 (anode layer / first electrode layer) and hole injection in a pixel region 100 surrounded by a partition wall on an element substrate 10. An organic EL element 2 in which an organic functional layer 20 including a transport layer 21 and a light emitting layer 22 and a cathode layer 12 (second electrode layer) are sequentially stacked is provided. Here, as will be described later, the organic functional layer 20 is solidified after discharging a liquid composition in which an organic fluorescent material or the like is dissolved and dispersed in a solvent (including a dispersion medium) onto the element substrate 10 by an inkjet method. The partition wall 5 functions as a bank that prevents the liquid composition from protruding from a predetermined region when the liquid composition is discharged. A sealing substrate 9 is disposed opposite to the surface of the element substrate 10 on which the organic EL element 2 is formed. The sealing substrate 9 and the element substrate 10 are sealed with an epoxy resin or the like applied on the entire surface thereof. The resin 90 is bonded together.

(Configuration of each pixel area)
FIGS. 3A, 3B, and 3C are respectively plan views of one pixel region of the organic EL device according to Embodiment 1 of the present embodiment, taken along line A1-A1 ′ in FIG. FIG. 4 is a cross-sectional view schematically showing a state where the pixel region is cut along the line, and a cross-sectional view schematically showing a state where the pixel region is cut along the line B1-B1 ′ of FIG. Since the structure of the circuit portion and the like of the organic EL device is well known, detailed description thereof is omitted. As shown in FIGS. 3A, 3B, and 3C, the cross-sectional structure of the organic EL device 1 of the present embodiment is generally on the surface side of the element substrate 10, and the wiring and thin film transistor described with reference to FIG. Is formed through an interlayer insulating film. A transparent pixel electrode 11 made of ITO or the like is patterned and formed in a predetermined shape on the uppermost interlayer insulating film 30, and the pixel electrode 11 is electrically connected to the thin film transistor 123.

  A region where the pixel electrode 11 is formed is a pixel region 100, and in this embodiment, has a rectangular planar shape. In the pixel region 100, an insulating layer 6 made of a silicon oxide film or the like is formed on the pixel electrode 11. In the insulating layer 6, a plurality of openings 61 are formed in two rows along the longitudinal direction in the central region 100 d (effective pixel region / effective light emitting region) of the pixel region 100. The surface of is exposed.

  On the insulating layer 6, a partition wall 5 made of, for example, an acrylic resin or a polyimide resin having a height of 0.1 to 3.5 μm is formed so as to surround the pixel region 100. In this region, an organic functional layer 20 is stacked on the upper layer side of the first insulating layer 6. A cathode layer 12 is formed on the organic functional layer 20, and the pixel electrode 11, the organic functional layer 20, and the cathode layer 12 constitute the organic EL element 2.

  The organic functional layer 20 includes, for example, a hole injection transport layer 21 stacked on the pixel electrode 11 and a light emitting layer 22 stacked on the hole injection transport layer 21. In addition, other organic functional layers having other functions, such as an interlayer layer or an electron transport layer, may be formed adjacent to the light emitting layer 22. The hole injection transport layer 21 has a function of injecting holes into the light emitting layer 22 and a function of transporting holes. In the light emitting layer 22, holes injected from the hole injecting and transporting layer 21 and electrons injected from the cathode layer 12 are recombined in the light emitting layer to emit light. Here, the light emitting layer 22 emits white light in all the pixel regions 100, or a red light emitting layer that emits red (R) for each color corresponding to the plurality of pixel regions 100, and green (G). The green light emitting layer that emits light and the blue light emitting layer that emits blue (B) are formed.

The hole injecting and transporting layer 21 is formed by discharging a hole injecting and transporting layer forming material and a solvent (including a dispersion medium) liquid composition inside the partition wall 5 and then removing the solvent, as will be described later. It is. The light emitting layer 22 is also formed by discharging a liquid composition containing a light emitting layer forming material and a solvent (including a dispersion medium) to the inside of the partition wall 5 and then removing the solvent. Thus, when forming the positive hole injection transport layer 21 and the light emitting layer 22, the partition 5 has the function which prevents that a liquid composition protrudes outside. For this reason, the partition wall 5 may be subjected to plasma treatment using CF ₄ gas to increase the water repellency of the partition wall 5.

  The cathode layer 12 is formed in a stripe shape over almost the entire surface of the element substrate 10 or across the plurality of pixel regions 100, and plays a role of flowing current through the organic functional layer 20 in pairs with the pixel electrode 11. The cathode layer 12 is configured by, for example, laminating a calcium layer and an aluminum layer. At this time, it is preferable to provide a cathode with a low work function on the side closer to the light emitting layer. In this embodiment, the cathode layer 12 is in direct contact with the light emitting layer 22 and plays a role of injecting electrons into the light emitting layer 22. Depending on the material of the light emitting layer 22, the light emitting layer 22 is intended to increase the light emission efficiency. An electron injection layer such as LiF may be formed between the cathode layer 12 and the cathode layer 12.

  The organic EL device 1 of this embodiment is, for example, a bottom emission type that emits light from the element substrate 10 side, and the cathode layer 12 is made of a reflective material such as Al (aluminum). Therefore, the light emitted from the organic functional layer 20 to the element substrate 10 side is transmitted through the circuit unit 3 and the element substrate 10 and emitted to the lower side (observer side) of the element substrate 10 and from the organic functional layer 20. The light emitted to the opposite side of the element substrate 10 is reflected by the cathode layer 12, passes through the circuit portion 3 and the element substrate 10, and is emitted to the lower side (observer side) of the element substrate 10. . If the cathode layer 12 is formed in a light transmissive state using ITO, Pt, Ir, Ni, Pd, Al or the like, and a reflective layer is formed on the lower layer side of the pixel electrode 11, the cathode layer 12 side It can be configured as a top emission type that emits light.

(Detailed configuration of each pixel region and the effect of this embodiment)
In the organic EL device 1 of the present embodiment, the heat radiation layer 8 having higher thermal conductivity than the partition wall 5 is formed at both end portions 100e and 100f in the longitudinal direction of the pixel region 100. The heat dissipation layer 8 is formed in a region shifted from the central region 100 d and is formed on the organic functional layer 20 on the lower layer side of the cathode layer 12 in the pixel region 100. The heat dissipation layer 8 is made of a clay mineral such as talc, mica, or sericite, a resin containing a filler such as titanium oxide, barium sulfate, or carbon black, or an inorganic insulating material such as silicon oxide or silicon nitride. It is configured. If a filler is blended in the resin, the thermal conductivity of the resin can be increased, and if it is a resin, it is suitable for forming the heat dissipation layer 8 thick. Moreover, if it is an inorganic insulating material, the thermal radiation layer 8 with high heat conductivity compared with resin can be comprised.

  In this embodiment, the heat dissipation layer 8 projects upward from the upper end surface of the partition wall 5, and a part of the cathode layer 12 overlaps the upper end surface of the heat dissipation layer 8. For this reason, the portion of the cathode layer 12 directly laminated on the organic functional layer 20 is at a position lower than the upper end surface of the partition wall 5, but the portion of the cathode layer 12 laminated on the upper end surface of the heat dissipation layer 8 is , A position higher than the upper end surface of the partition wall 5, that is, a position close to the sealing substrate 9. In this embodiment, a portion of the cathode layer 12 laminated on the upper end surface of the heat dissipation layer 8 is not in contact with the sealing substrate 9, and a sealing resin 90 such as an epoxy resin is provided between the cathode substrate 12 and the sealing substrate 9. Is intervening.

  As described above, in the organic EL device 1 according to the present embodiment, the heat radiation layer 8 having higher thermal conductivity than the partition wall 5 is formed at both ends 100e and 100f in the longitudinal direction of the pixel region 100. Projects upward from the upper end surface. A part of the cathode layer 12 overlaps the upper end surface of the heat dissipation layer 8. For this reason, when the organic EL element 2 is driven, the heat generated in the organic functional layer 20 escapes to the sealing substrate 9 through the cathode layer 12, but in this embodiment, the heat generated in the organic functional layer 20 is Also escapes to the sealing substrate 9 through the heat dissipation layer 8 and the cathode layer 12. Moreover, since the heat dissipation layer 8 protrudes upward from the upper end surface of the partition wall 5, the portion of the cathode layer 12 that overlaps the upper end surface of the heat dissipation layer 8 is also positioned above the upper end surface of the partition wall 5, close. Therefore, according to this embodiment, the heat generated in the organic functional layer 20 can be efficiently released through the sealing substrate 9.

  Further, since the sealing resin 90 is interposed between the element substrate 10 and the sealing substrate 9, heat from the element substrate 10 can be efficiently released to the sealing substrate 9. Therefore, since the temperature rise of the organic EL element 2 can be suppressed low, the reliability of the organic EL device 1 can be improved.

  The heat dissipation layer 8 is formed at both end portions 100e and 100f in the pixel region 100, and is formed in a region that avoids the central region 100d (effective light emitting region). For this reason, the heat radiation layer 8 can be provided without reducing the amount of light emitted from the organic EL element 2.

  In this embodiment, when the organic EL device 1 is a bottom emission type, a light shielding resin material may be used as the sealing resin 90. Here, if a material containing a filler is used as the sealing resin 90, heat from the element substrate 10 can be efficiently released to the sealing substrate 9. On the other hand, when the organic EL device 1 is a top emission type, a translucent resin material may be used as the sealing resin 90.

(Configuration of droplet discharge head)
4 (a), 4 (b), and 4 (c) are explanatory diagrams schematically showing the internal structure of a droplet discharge head used when manufacturing each, and an explanatory diagram of a pressure generating element in a flexural vibration mode. It is explanatory drawing of the pressure generating element of a longitudinal vibration mode.

  In manufacturing the organic EL device 1 of this embodiment, the hole injection transport layer 21 and the light emitting layer 22 are formed using a droplet discharge method. In that case, a droplet discharge head described with reference to FIGS. 4A, 4B, and 4C is used. As shown in FIG. 4A, the droplet discharge head 322 is connected to a liquid composition storage unit 337 such as a tank shape or a cartridge shape for storing the liquid composition M discharged as droplets. The droplet discharge head 322 includes a nozzle row formed by arranging a large number of nozzle openings 327 in a row. In such a droplet discharge head 322, the nozzle row extends in the sub-scanning direction intersecting the main scanning direction, and the liquid composition M is transferred to the liquid composition M while the droplet discharging head 322 moves in the main scanning direction. By selectively discharging from the nozzle opening 327, the droplet M0 is landed at a predetermined position on the element substrate 10. Further, the droplet discharge head 322 can move the main scanning position by the droplet discharge head 322 at a predetermined interval by moving in parallel in the sub-scanning direction by a predetermined distance.

  As shown in FIGS. 4A and 4B, the droplet discharge head 322 includes, for example, a stainless steel nozzle plate 329, an elastic plate 331 facing the nozzle plate 329, and a plurality of partition members 332 that join them together. have. A plurality of pressure generation chambers 333 and liquid reservoirs 334 are formed between the nozzle plate 329 and the elastic plate 331 by the partition member 332, and the plurality of pressure generation chambers 333 and liquid reservoirs 334 are connected via the liquid composition flow inlet 338. Communicate with each other. A liquid composition supply hole 336 is formed at an appropriate position of the elastic plate 331, and the liquid composition reservoir 337 is connected to the liquid composition supply hole 336. Accordingly, the liquid composition reservoir 337 supplies the liquid composition M to be discharged to the liquid composition supply hole 336. The supplied liquid composition M fills the liquid reservoir 334 and further fills the pressure generating chamber 333 through the liquid composition flow inlet 338. In this way, the liquid composition reservoir 337 and each pressure generating chamber 333 communicate with each other.

  The nozzle plate 329 is provided with a nozzle opening 327 for ejecting the liquid composition M as a droplet M0 from the pressure generating chamber 333, and the nozzle forming surface where the nozzle opening 327 is open is a flat surface. ing. In this way, the nozzle opening 327 is opened in the pressure generation chamber 333. A pressure generating element 339 is attached to the back surface of the elastic plate 331 forming the pressure generating chamber 333 so as to correspond to the pressure generating chamber 333. For example, as shown in FIG. 4B, the pressure generating element 339 is a piezoelectric element in a flexural vibration mode including a piezoelectric element 341 and a pair of electrodes 342 a and 342 b that sandwich the piezoelectric element 341. The vibration direction is indicated by an arrow C. As shown in FIG. 4C, the pressure generating element 339 may be a longitudinal vibration mode piezoelectric element. This longitudinal vibration mode piezoelectric element (pressure generating element 339) is configured by alternately laminating piezoelectric materials and conductive materials in parallel to the extending direction, with the tip fixed to an elastic plate 331 and the other end based on a base. It is fixed to the base 320. Such a pressure generating element 339 contracts in a direction perpendicular to the stacking direction of the conductive layers in the charged state, and extends in a direction perpendicular to the conductive layer when the charged state is released.

  In any case, any piezoelectric element is deformed by a drive signal applied between the electrodes, and the pressure generating chamber 333 is expanded and contracted. In addition, a liquid repellent layer 343 made of, for example, a Ni-tetrafluoroethylene eutectoid plating layer is provided in the periphery of the nozzle opening 327 in order to prevent the flying of the droplet M0 and the clogging of the nozzle opening 327. .

(Manufacturing method of the organic EL device 1)
A method for manufacturing the organic EL device 1 of the present embodiment will be described with reference to FIG. 5A and 5B are cross-sectional views of the element substrate 10 before forming the organic functional layer 20 and a cross-section corresponding to one pixel region in the organic EL device according to Embodiment 1 of the present invention. FIG.

  In manufacturing the organic EL device 1 of this embodiment, first, as shown in FIGS. 5A and 5B, the circuit unit 3 is formed using various semiconductor processes. Next, after an ITO film is formed on the interlayer insulating film 30, the ITO film is patterned by using a photolithography technique to form the pixel electrode 11. Next, after forming an insulating film on the upper layer of the pixel electrode 11, the insulating film is patterned by using a photolithography technique to form the insulating layer 6 including the opening 61. Next, a resin layer such as acrylic resin or polyimide resin is applied to the entire surface of the element substrate 10 by spin coating or the like, and then exposed and developed to form the partition walls 5 at the same time. In this state, the pixel region 100 is a concave portion 100 a surrounded by the partition wall 5.

  Next, in the hole injecting and transporting layer forming liquid application step, the liquid composition 21a containing the hole injecting and transporting layer forming material is discharged into the recess 100a from the droplet discharge head 322 described with reference to FIG. The liquid composition 21a discharged in this manner lands in the recess 100a and spreads to both end portions 100e and 100f within the recess 100a. Here, as the liquid composition 21a, 3,4-polyethylenediosithiophene / polystyrene sulfonic acid (PEDOT / PSS) which is a polyolefin derivative, polyphenylene vinylene whose polymer precursor is polytetrahydrothiophenylphenylene, 1, 1 A composition in which a hole injecting and transporting layer forming material such as -bis- (4-N, N-ditolylaminophenyl) cyclohexane is dissolved in a polar solvent can be used. Examples of the polar solvent include glycol ethers such as isopropyl alcohol, normal butanol, γ-butyrolactone, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone and derivatives thereof, carbitol acetate, and butyl carbitol acetate. And the like.

  Next, a hole injection transport layer fixing step is performed. For this purpose, the discharged liquid composition is heated and dried, the polar solvent contained in the liquid composition 21a is evaporated, and the hole injection transport layer 21 is fixed. The fixing process is performed, for example, in a nitrogen atmosphere at room temperature and a pressure of, for example, about 133.3 Pa (1 Torr). If the pressure is too low, the liquid composition 21a is bumped, which is not preferable. On the other hand, if the temperature is higher than room temperature, the evaporation rate of the polar solvent increases and a flat film cannot be formed. After the drying treatment, it is preferable to completely remove the polar solvent and water remaining in the hole injecting and transporting layer 21 by performing a heat treatment in nitrogen, preferably in vacuum, at about 200 ° C. for about 10 minutes.

  Next, the light emitting layer 22 is formed, but before that, a surface modification step for the hole injecting and transporting layer 21 may be performed. In the light emitting layer forming step, a non-polar solvent that is insoluble in the hole injecting and transporting layer 21 is used as a solvent for the liquid composition used in forming the light emitting layer in order to prevent re-dissolution of the hole injecting and transporting layer 21. Use. However, since the hole injecting and transporting layer 21 has low affinity for the nonpolar solvent, even when a liquid composition containing the nonpolar solvent is discharged onto the hole injecting and transporting layer 21, the hole injecting and transporting layer 21 emits light. There is a possibility that the layer 22 cannot be adhered, or the light emitting layer 22 cannot be applied uniformly. Therefore, before the light emitting layer forming step, a surface modifier made of the same solvent as the non-polar solvent of the liquid composition used for forming the light emitting layer 22 or a similar solvent, such as cyclohexylbenzene, dihydro Benzofuran, trimethylbenzene, tetramethylbenzene, toluene, xylene, or a mixture thereof is applied onto the hole injecting and transporting layer 21 by the ink jet method (droplet discharge method), spin coating method or dipping method, and then dried. By performing such a surface modification step, the surface of the hole injecting and transporting layer 21 is easily adapted to the nonpolar solvent, and in the subsequent step, the liquid composition containing the light emitting layer forming material is added to the hole injecting and transporting layer. 21 can be uniformly applied. Note that a composition in which a hole transporting material is dissolved in the surface modifying material may be applied onto the hole injecting and transporting layer 21 by an ink jet method and dried.

  Thereafter, although not shown in the drawings, in the light emitting layer forming step, a liquid composition containing the light emitting layer layer forming material from the droplet discharge head 322 described with reference to FIG. Is discharged into the recess 100a. The liquid composition thus ejected lands in the recess 100a and spreads in the upper layer of the hole injecting and transporting layer 21 in the recess 100a. Examples of such a liquid composition include polyfluorene derivatives, polyphenylene derivatives, polyvinyl carbazole, polythiophene derivatives, or polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes such as rubrene, perylene, 9, 10 -The thing which mix | blended the light emitting layer forming material doped with diphenylanthracene, tetraphenyl butadiene, Nile red, coumarin 6, quinacridone etc. in the nonpolar solvent is used. As a light-emitting layer forming material, a π-conjugated polymer material in which double-bonded π electrons are non-polarized on a polymer chain is also a conductive polymer, so that it has excellent light-emitting performance and is therefore preferably used. . In particular, a compound having a fluorene skeleton in the molecule, that is, a polyfluorene compound is more preferably used. In addition to such materials, for example, a composition for an organic EL device disclosed in JP-A-11-40358, that is, a precursor of a conjugated polymer organic compound, and at least one kind for changing light emission characteristics A composition for an organic EL device comprising the above fluorescent dye can also be used as a light emitting layer forming material. Moreover, as a nonpolar solvent, what is insoluble with respect to the positive hole injection transport layer 21 is preferable, for example, cyclohexylbenzene, dihydrobenzofuran, trimethylbenzene, tetramethylbenzene etc. can be used. By using such a nonpolar solvent for the liquid composition for forming the light emitting layer, the liquid composition for forming the light emitting layer can be applied without re-dissolving the hole injection transport layer 21.

  Next, a light emitting layer fixing step is performed. For this purpose, the discharged liquid composition is heated and dried, the nonpolar solvent contained in the liquid composition is evaporated, and the light emitting layer 22 is fixed. The fixing process is performed, for example, in a nitrogen atmosphere at room temperature at a pressure of about 133.3 Pa (1 Torr) for 5 to 10 minutes. If the pressure is too low, the liquid composition will be bumped, which is not preferable. On the other hand, when the temperature is set to room temperature or higher, the evaporation rate of the nonpolar solvent increases, and a large amount of the light emitting layer forming material adheres to the wall surface of the partition wall 5, which is not preferable. Examples of other drying means include a far-infrared irradiation method and a high-temperature nitrogen gas spraying method.

  After forming the organic functional layer 20 (the hole injecting and transporting layer 21 and the light emitting layer 22) in this way, the light emitting layer 22 is formed by using a photolithography technique as described with reference to FIGS. A heat dissipation layer 8 is formed by patterning on the substrate. Moreover, when the base material of the heat radiating layer 8 is a photosensitive resin, the heat radiating layer 8 may be formed by applying, exposing, and developing such a resin material. Then, after sufficiently drying and desorbing moisture from the organic functional layer 20, the cathode layer 12 is formed on the organic functional layer 20 and the heat dissipation layer. Thereafter, the surface of the cathode layer 12 is covered with the sealing substrate 9 using the sealing resin 90.

[Embodiment 2]
FIG. 6 is a cross-sectional view of an organic EL device according to Embodiment 2 of the present invention. FIG. 6A shows a state in which the pixel region is cut along the line A1-A1 ′ of FIG. 6B corresponds to a schematic cross-sectional view, and FIG. 6B corresponds to a cross-sectional view schematically illustrating a state in which the pixel region is cut along the line B1-B1 ′ in FIG. Since the basic configuration of the present embodiment is the same as that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 6A and 6B, in the organic EL device 1 of the present embodiment as well, in the longitudinal direction of the pixel region 100, both ends 100 e and 100 f in the longitudinal direction of the pixel region 100 conduct heat from the partition wall 5. The heat dissipation layer 8 having high properties is formed, and the heat dissipation layer 8 projects upward from the upper end surface of the partition wall 5. A part of the cathode layer 12 overlaps the upper end surface of the heat dissipation layer 8. For this reason, the heat generated in the organic functional layer 20 can be efficiently released through the sealing substrate 9.

  Here, the sealing resin 90 is interposed between the element substrate 10 and the sealing substrate 9. Of the sealing resin 90 of this embodiment, the portion overlapping with the heat dissipation layer 8 has high thermal conductivity by blending clay minerals such as talc, mica and sericite, and fillers such as titanium oxide, barium sulfate and carbon black. A resin material 91 is used. On the other hand, a translucent resin material 92 is used in a region where the heat dissipation layer 8 is not formed. Therefore, the heat from the element substrate 10 can be efficiently released to the sealing substrate 9 and the sealing resin 90 made of the translucent resin material 92 is used even when the organic EL device 1 is a top emission type. Thus, light can be emitted from the sealing substrate 9 side.

  In addition, about the part which overlaps with the thermal radiation layer 8, while using the resin material 91 with high thermal conductivity by mixing | blending a filler, the structure which does not arrange | position sealing resin 90 in the area | region in which the thermal radiation layer 8 is not formed is employ | adopted. Also good. Even when configured in this way, heat can be efficiently released from the element substrate 10 to the sealing substrate 9 and even when the organic EL device 1 is a top emission type, it is made of a translucent resin material 92. Light can be emitted from the side of the sealing substrate 9 through the sealing resin 90.

[Embodiment 3]
FIG. 7 is a cross-sectional view of an organic EL device according to Embodiment 3 of the present invention, and FIGS. 7A, 7B, and 7C each show an organic EL device according to Embodiment 3 of the present invention. FIG. 3 is a longitudinal sectional view showing the overall configuration of FIG. 1, a sectional view schematically showing the organic EL device 1 cut at a position corresponding to the line A1-A1 ′ in FIG. 3A, and the organic EL device 1 It is sectional drawing which shows typically a mode that it cut | disconnected in the position corresponded to the B1-B1 'line | wire of Fig.3 (a). Since the basic configuration of the present embodiment is the same as that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 7A, 7 </ b> B, and 7 </ b> C, in the organic EL device 1 of the present embodiment, as in the first embodiment, both end portions 100 e and 100 f in the longitudinal direction of the pixel region 100 have partition walls. 5 is formed, and the heat dissipation layer 8 protrudes upward from the upper end surface of the partition wall 5. A part of the cathode layer 12 overlaps the upper end surface of the heat dissipation layer 8. For this reason, the heat generated in the organic functional layer 20 can be efficiently released through the sealing substrate 9.

  Here, although the element substrate 10 and the sealing substrate 9 are bonded to each other by the sealing resin 90, the sealing resin 90 is disposed only along the outer periphery of the sealing substrate 9, and the pixel region 100 has no Not placed. When comprised in this way, it can respond to any organic EL device 1 of a bottom emission type and a top emission type.

[Embodiment 4]
FIG. 8 is a cross-sectional view of an organic EL device according to Embodiment 4 of the present invention. FIG. 8A shows a state in which the pixel region is cut along the line A1-A1 ′ of FIG. 8B corresponds to a cross-sectional view schematically showing a state in which the pixel region is cut along the line B1-B1 ′ of FIG. 3A. Since the basic configuration of the present embodiment is the same as that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 8A and 8B, also in the organic EL device 1 of this embodiment, heat conduction from the partition wall 5 to both end portions 100 e and 100 f in the longitudinal direction of the pixel region 100, as in the first embodiment. The heat dissipation layer 8 having high properties is formed, and the heat dissipation layer 8 projects upward from the upper end surface of the partition wall 5. A part of the cathode layer 12 overlaps the upper end surface of the heat dissipation layer 8. For this reason, the heat generated in the organic functional layer 20 can be efficiently released through the sealing substrate 9.

  Here, the portion of the element substrate 10 where the heat dissipation layer 8 is formed is in surface contact with the sealing substrate 9. For this reason, the heat from the element substrate 10 can be efficiently released to the sealing substrate 9. In the pixel region 100, either a configuration in which the sealing resin 90 is present in a region where the heat dissipation layer 8 is not formed or a configuration in which the sealing resin 90 is not present may be employed. In the pixel region 100, when the sealing resin 90 is not formed in a region where the heat dissipation layer 8 is not formed, or when the sealing resin 90 formed in the pixel region 100 is made of a translucent resin material, Both the emission type and top emission type organic EL devices 1 can be used.

[Embodiment 5]
FIG. 9 is a cross-sectional view of an organic EL device according to Embodiment 5 of the present invention. FIG. 9A shows a state in which the pixel region is cut along the line A1-A1 ′ of FIG. 9B corresponds to a schematic cross-sectional view, and FIG. 9B corresponds to a cross-sectional view schematically showing a state in which the pixel region is cut along the line B1-B1 ′ of FIG. Since the basic configuration of the present embodiment is the same as that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 9A and 9B, in the organic EL device 1 of the present embodiment as well, in the same way as in the first embodiment, heat conduction from the partition wall 5 to both ends 100e and 100f in the longitudinal direction of the pixel region 100. The heat dissipation layer 8 having high properties is formed, and the heat dissipation layer 8 projects upward from the upper end surface of the partition wall 5. A part of the cathode layer 12 overlaps the upper end surface of the heat dissipation layer 8. For this reason, the heat generated in the organic functional layer 20 can be efficiently released through the sealing substrate 9.

  Here, the portion of the element substrate 10 where the heat dissipation layer 8 is formed is in contact with the sealing substrate 9. In addition, in the sealing substrate 9, a recess 9a is formed in a portion overlapping the portion where the heat dissipation layer 8 of the element substrate 10 is formed, and the upper end portion of the portion where the heat dissipation layer 8 is formed is located in the recess 9a. ing. For this reason, since the contact area between the element substrate 10 side and the sealing substrate 9 side is wide, the heat generated in the organic functional layer 20 can be efficiently released through the sealing substrate 9. In this embodiment, either a configuration in which the sealing resin 90 is present or a configuration in which the sealing resin 90 is not present may be employed in a region where the heat dissipation layer 8 is not formed in the pixel region 100. In the pixel region 100, when the sealing resin 90 is not formed in a region where the heat dissipation layer 8 is not formed, or when the sealing resin 90 formed in the pixel region 100 is made of a translucent resin material, Both the emission type and top emission type organic EL devices 1 can be used.

[Other embodiments]
In the above embodiment, the configuration in which the heat dissipation layer 8 protrudes upward from the upper end surface of the partition wall 5 is adopted. However, even when the heat dissipation layer 8 is positioned lower than the upper end surface of the partition wall 5, The portion overlapping the upper end surface of 5 is pushed upward from the portion directly overlapping the organic functional layer 20. Therefore, the heat dissipation from the organic functional layer 20 to the sealing substrate 9 can be improved.

  In the above embodiment, the organic EL device 1 in which the pixel regions 100 are arranged in a matrix as shown in FIG. 1 has been described as an example. However, as in the organic EL device 1 used for a line head of an image forming apparatus such as a copying machine. In addition, the present invention may be applied to a type in which the pixel regions 100 are arranged in a line.

1 is a block diagram showing an electrical configuration of an active matrix organic EL display device as an example of an organic EL device to which the present invention is applied. It is a longitudinal cross-sectional view which shows the whole structure of the organic EL apparatus which concerns on Embodiment 1 of this invention. (A), (b), (c) is a plan view for one pixel region of the organic EL device according to the first embodiment of the present invention, along the line A1-A1 'in FIG. 3 (a). It is sectional drawing which shows a mode that the pixel area | region was cut | disconnected typically, and sectional drawing which shows a mode that the pixel area | region was cut | disconnected along B1-B1 'line of Fig.3 (a). (A), (b), (c) is an explanatory view schematically showing the internal structure of a droplet discharge head used in manufacturing an organic EL device to which the present invention is applied, and pressure in a flexural vibration mode. It is explanatory drawing of a generating element, and explanatory drawing of the pressure generating element of a longitudinal vibration mode. (A), (b) is each the sectional drawing of the element substrate before forming an organic functional layer, and sectional drawing for one pixel area in the organic EL device concerning Embodiment 1 of the present invention. It is sectional drawing of the organic electroluminescent apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing of the organic electroluminescent apparatus which concerns on Embodiment 3 of this invention. It is sectional drawing of the organic electroluminescent apparatus which concerns on Embodiment 4 of this invention. It is sectional drawing of the organic electroluminescent apparatus which concerns on Embodiment 5 of this invention. It is sectional drawing of the conventional organic electroluminescent apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Organic EL device 2 ... Organic EL element 5 ... Bulkhead 6 ... Insulating layer 8 ... Heat radiation layer 9 ... Sealing substrate 9a ... Concave part of sealing substrate 10 ... Element substrate 11... Pixel electrode (first electrode) 12.. Cathode layer (second electrode) 20.. Organic functional layer 21.. Hole injection transport layer (organic functional layer) 22.・ Light emitting layer (organic functional layer) 90 ..Sealing resin, 100 ..Pixel region, 100 d ..Center region of pixel region, 100 e, 100 f.

Claims (13)

Organic having an element substrate in which an organic electroluminescent element in which a first electrode layer, an organic functional layer including at least a light emitting layer, and a second electrode layer are sequentially stacked in a pixel region surrounded by a partition wall is formed In electroluminescence equipment,
An organic electroluminescence device characterized in that a heat radiation layer having higher thermal conductivity than the partition is laminated on a part of the organic functional layer on a lower layer side of the second electrode layer in the pixel region. .   The organic electroluminescence device according to claim 1, wherein the heat dissipation layer is formed at an end portion in the pixel region.   The organic electroluminescence device according to claim 1, wherein the heat dissipation layer is made of a resin mixed with a filler.   The organic electroluminescence device according to claim 1, wherein the heat dissipation layer is made of an inorganic insulating material.   5. The organic electroluminescent device according to claim 1, wherein a part of the second electrode layer is laminated on an upper end surface of the heat dissipation layer.   The organic electroluminescent device according to claim 1, wherein the heat dissipation layer protrudes upward from an upper end surface of the partition wall. In the element substrate, a sealing substrate is disposed opposite to the surface on which the organic electroluminescence element is formed,
The organic electroluminescence device according to claim 1, wherein the sealing substrate is bonded to the element substrate with a sealing resin.   The organic electroluminescence device according to claim 7, wherein the sealing resin is disposed in a region overlapping with the pixel region.   9. The organic electroluminescence device according to claim 8, wherein in the sealing resin, at least a resin portion disposed in a portion of the pixel region where the heat dissipation layer is formed includes a filler. The sealing substrate is translucent,
10. The organic electroluminescence according to claim 8, wherein in the sealing resin, at least a resin portion disposed in a region where the heat dissipation layer is not formed in the pixel region is translucent. apparatus. The surface of the element substrate on which the organic electroluminescence element is formed is bonded to a sealing substrate,
The organic electroluminescence device according to claim 6, wherein a portion of the element substrate where the heat dissipation layer is formed is in contact with the sealing substrate. In the sealing substrate, a recess is formed in a portion overlapping the portion where the heat dissipation layer is formed,
The organic electroluminescence device according to claim 11, wherein an upper end portion of a portion where the heat dissipation layer is formed in the element substrate is located in the concave portion.   The organic electroluminescent device according to any one of claims 1 to 12, wherein the organic functional layer is formed by solidifying a liquid composition disposed in the pixel region.

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