JP2007109564A - Light emitting element and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting element capable of enhancing luminous efficiency because the light emitting elements can be arranged with high density. <P>SOLUTION: This light emitting element has a luminescent layer deposited between first and second electrodes facing each other in parallel, an organic semiconductor layer deposited between the luminescent layer and the first electrode, and an auxiliary electrode disposed on the reverse side opposite to the surface of the first electrode, which faces the second electrode, and also has a structure in which a second auxiliary electrode disposed on the reverse side opposite to the surface of the second electrode, which faces the first electrode, through a second luminescent layer, a third electrode, and a second organic semiconductor layer is laminated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light-emitting element and a display device using a compound having carrier transportability (hole or electron mobility) and including a semiconductor layer made of such a compound.

  At present, attention is focused on light-emitting elements that use electroluminescence (hereinafter simply referred to as EL) due to recombination of carriers (holes or electrons) in a substance that emits light by applying an electric field. For example, an EL display device equipped with a display panel using an injection type organic EL element using an organic compound material has been developed. The organic EL element includes a red EL element having a structure emitting red light, a green EL element having a structure emitting green light, and a blue EL element having a structure emitting blue light. A color display device can be realized by arranging these three organic EL elements that emit light of red, blue, and green RGB as a one-pixel light-emitting unit and arranging a plurality of pixels in a matrix on the panel portion. As a driving method of a display panel using such a color display device, a passive matrix driving type and an active matrix driving type are known. An active matrix driving type EL display device has advantages such as low power consumption and less crosstalk between pixels compared with a passive matrix type display device, and particularly, a large screen display device and a high definition display. Suitable for equipment.

  In the display panel of an active matrix drive type EL display device, an anode power supply line, a cathode power supply line, a scanning line responsible for horizontal scanning, and signal lines arranged crossing each scanning line are formed in a grid pattern. Yes. An RGB subpixel is formed at each RGB intersection of the scanning line and the signal line.

  For each subpixel, a scanning line is connected to the gate of a field effect transistor (FET) for scanning line selection, a signal line is connected to the drain, and a light emission driving FET is connected to the source. The gate is connected. A drive voltage is applied to the source of the light emission drive FET via the anode power supply line, and the anode end of the EL element is connected to the drain D thereof. A capacitor is connected between the gate and source of the light emission drive FET. Further, a ground potential is applied to the cathode end of the EL element via a cathode power supply line.

  Conventional organic light-emitting elements represented by organic EL elements are basically elements exhibiting diode characteristics, and most of them are manufactured by passive matrix driving. In the passive matrix driving method, high luminance is required instantaneously because line-sequential driving is performed, and it is difficult to obtain a high-definition display device because the limit number of scanning lines is limited. In recent years, an organic EL display using a TFT using polysilicon or the like has been studied. However, the process temperature is high, the manufacturing cost per unit area is high, and it is not suitable for a large screen. In addition, when organic EL is actively driven using TFTs, two or more transistors and one or more capacitors must be arranged in one pixel. However, since the TFT itself has a planar structure, the aperture ratio is high. In order to obtain the luminance required for the display at the expense of the above, there is a drawback that the organic EL must be made to emit a high current by flowing a large current.

For example, in the prior invention (see Patent Document 1), as shown in FIG. 1, a light emitting body comprising an anode and a cathode that is disposed at least partially facing the substrate via a light emitting material layer. The voltage direction applied between the anode and the cathode in the structure in which the auxiliary electrode is formed on the surface opposite to the surface facing the cathode via the light emitting material layer of the anode via the insulating layer A voltage is applied between the auxiliary electrode and the cathode so as to be in the same direction. In this case, since the maximum permissible current amount of the element itself is limited, there is a problem that in order to increase the maximum luminance, the material used for the light emitting layer must be changed to improve the light emission efficiency of the light emitting material itself.
JP 2002-343578 A

  An example of a problem to be solved by the present invention is to provide a light-emitting element that can be arranged at a high density and can improve luminous efficiency.

The light emitting device according to claim 1, wherein a light emitting layer formed between first and second electrodes facing in parallel,
An organic semiconductor layer formed between the light emitting layer and the first electrode;
A light-emitting element comprising: an auxiliary electrode disposed on an opposite side of a surface of the first electrode facing the second electrode via an insulating layer;
A second auxiliary electrode disposed on the opposite side of the surface of the second electrode facing the first electrode through a second light emitting layer, a third electrode, a second organic semiconductor layer, and a second insulating layer is laminated. It has the structure which was made.

The display device according to claim 15 is a display device in which a plurality of light emitting units are arranged in a matrix.
Each of the light emitting portions includes a light emitting layer formed between first and second electrodes facing in parallel,
An organic semiconductor layer formed between the light emitting layer and the first electrode;
A light-emitting element comprising: an auxiliary electrode disposed on an opposite side of a surface of the first electrode facing the second electrode via an insulating layer;
A second auxiliary electrode disposed on the opposite side of the surface of the second electrode facing the first electrode through a second light emitting layer, a third electrode, a second organic semiconductor layer, and a second insulating layer is laminated. It has the structure which was made.

  According to the above configuration, it is possible to reduce the number of devices arranged in one pixel when performing active matrix driving, and the cost can be reduced compared to an organic EL display device using polysilicon or the like. Low power consumption and long life can be achieved. Furthermore, the light-emitting element exhibits switching characteristics and can be easily manufactured without greatly changing the organic EL manufacturing process.

  Furthermore, according to the above configuration, for example, by using a structure in which two stacked light emitting element portions emit light of substantially the same color, the light emission efficiency can be improved as compared with the conventional structure. That is, in the structure of the prior invention, the maximum allowable current amount of the element itself is limited, and in order to increase the luminance, the material used for the light emitting layer must be changed to improve the light emission efficiency of the light emitting material itself. Compared with the structure of the prior invention without changing the light emitting material, it is possible to flow more current, so that the light emission luminance can be improved up to about twice.

  In addition, since two or more display colors can be obtained from one light emitting element by using materials that can emit light of different wavelengths for the two light emitting layers, the configuration of a display device with few display colors can be simplified. In addition, by changing the voltages applied to the two auxiliary electrodes, it is possible to obtain a device in which the obtained emission spectrum changes.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, an organic EL display panel will be described with reference to the drawings as an example of a light emitting device according to an embodiment of the present invention.

  FIG. 2 shows a light emission formed on a substrate 1 having a light emitting layer 6 formed between a pair of opposed first and second electrodes (anode 4 and cathode 7) in an embodiment of the present invention. An organic EL element 114 of the element is shown.

  The organic EL element 114 has, as basic parts, an auxiliary electrode 2 as a first auxiliary electrode, an insulating layer 3 as a first insulating layer, an anode 4 as a first anode (first electrode), and a hole injection layer 5 as a basic part. After the first hole injection layer and the light emitting layer 6 are formed as the first light emitting layer, the cathode 7 (second electrode) is formed as a common electrode using a transparent conductive film, and then the second portion is formed on the base portion. The light emitting layer 6b, the second hole injection layer 5b, the second anode 4b (third electrode), the second insulating layer 3b, and the second auxiliary electrode 2b are formed in this order. Here, the hole injection layer 5 and the hole injection layer 5b belong to a carrier transporting organic semiconductor layer. In addition to the hole injection layer, the carrier transporting organic semiconductor layer may be, for example, a hole transport layer or a laminate thereof, a block layer, or the like. Further, although not shown in the figure, the carrier transporting organic semiconductor layer is inserted and disposed in at least one of the cathode 7 and the light emitting layer 6 and the second light emitting layer 6b, for example, an electron injection layer, an electron It may be a transport layer or a laminate thereof, or a block layer.

  The anode 4 and the second anode 4b are formed in a lattice-like, comb-like or saddle-like pattern. This is convenient for carriers passing through the organic semiconductor layer. That is, the anode 4 on the side of the organic semiconductor layer 5 such as a hole injection layer and a hole transport layer is formed so as to define a pattern for carriers passing through the organic semiconductor layer.

  Further, the first anode 4 and the second anode 4b may be electrically connected, and may be connected to independent circuits. Similarly, the first and second auxiliary electrodes 2 and 2b may be electrically connected to the auxiliary electrode, or may be connected independently. When different materials are used for the two light emitting layers 6 and 6b, the first anode and the second auxiliary electrode are more effective when controlling the emission color when the second anode and the second auxiliary electrode are connected separately from each other. To do.

  Since the organic EL element of this embodiment has two light emitting layers with one cathode interposed therebetween, the light emission luminance can be improved up to about twice at the same voltage by using the same light emitting layer material. In addition, by using different light emitting layer materials for the two light emitting layers, an element capable of expressing two or more colors can be obtained by changing the potential applied to the two auxiliary electrodes.

  In the present embodiment, a patterned auxiliary electrode 2 is formed on a glass substrate using a vacuum deposition method or the like, and an insulating layer 3 and a hole injection layer 5 are formed thereon using a vacuum deposition method, a spin coating method, or the like. Form. By forming the anode after forming the hole injection layer, the film-formability of the coating type hole injection material is improved, and the hole injection material formed not only by the coating type hole injection material but also by vacuum evaporation However, the current flowing through the cathode 7 and the light emission intensity when no voltage is applied to the anode (when OFF) can be reduced. As a result, the ratio of the current when the voltage is applied to the anode (ON), the emission intensity, the current when OFF, and the emission intensity are improved.

  The material of the substrate 1 is not limited to a translucent material such as plastic material such as glass, quartz, and polystyrene, but is made of an opaque material such as silicon or Al, a thermosetting resin such as phenol resin, or a thermoplastic resin such as polycarbonate. Although it can be used, it is not restricted to this.

As electrode materials of the auxiliary electrode 2, the anode 4, the second auxiliary electrode 2b, the second anode 4b, and the cathode 7, Ti, Al, Li: Al, Cu, Ni, Ag, Mg: Ag, Au, Pt, Pd, Examples thereof include metals such as Ir, Cr, Mo, W, and Ta, or alloys thereof. Alternatively, a conductive polymer such as polyaniline or PEDT: PSS can be used. Alternatively, an oxide transparent conductive thin film such as tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), indium oxide (In ₂ O ₃ ), zinc oxide (ZnO), or tin oxide (SnO ₂ ) is used. The main composition can be used, but is not limited thereto. The thickness of each electrode is preferably about 10 to 500 nm. A range of 50 to 300 nm is particularly suitable for the cathode 7 material and the auxiliary electrode 2. A range of about 10 to 200 nm is particularly suitable for the cathode 7 material. These electrode materials are preferably produced by vacuum deposition or sputtering.

  The difference between the work function value of the anode material (4, 4b) and the ionization potential value of the organic semiconductor layer 5 is preferably within 0.5 eV. The light emitting layer emits light when a voltage is applied between the auxiliary electrode and the electrode on the organic semiconductor layer side so as to be opposite to the voltage direction applied between the anode and the cathode. The material of the anode is selected from those whose work function value is smaller than the ionization potential value of the organic semiconductor layer 5. The work function Wf1 of the anode and the work function Wf2 of the carrier suppression layer BF are energy measured from the vacuum level (0 eV) to each Fermi level. The ionization potential Ip1 of the organic semiconductor layer 5 is energy measured from the vacuum level to the highest occupied molecular orbital (HOMO) level at the top of the valence band. The electron affinity Ea is energy measured from the vacuum level (VACUUM LEVEL) at the reference energy level of 0 eV to the lowest unoccupied molecular orbital (LUMO) level at the bottom of the conduction band.

Various insulating materials represented by SiO ₂ and Si ₃ N ₄ can be used for the insulating layer 3, but an inorganic oxide film having a high relative dielectric constant is particularly preferable. Inorganic oxides include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, strontium titanate, Examples thereof include barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and yttrium trioxide. Of these, silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable. Inorganic nitrides such as silicon nitride and aluminum nitride can also be suitably used. In addition, as an organic compound film, polyimide, polyamide, polyester, polyacrylate, photo radical polymerization type, photo cation polymerization type photo curable resin, or a copolymer containing an acrylonitrile component, polyvinyl phenol, polyvinyl alcohol, novolac resin, In addition, phosphazene compounds including anoethyl pullulan, polymer bodies, elastomer bodies, and the like can also be used.

  The hole injection layer 5 has a function of facilitating injection of holes from the anode 4 and a function of stably transporting holes. The material is a porphyrin derivative represented by copper phthalocyanine (CuPc), petacene. A high molecular weight arylamine called starburst amine typified by m-TDATA is often used in low molecular weight systems. Alternatively, a layer in which a Lewis acid, tetrafluorotetracyanoquinodimethane (F4-TCNQ), or the like is mixed with a porphyrin derivative, a triphenylamine derivative, or the like to increase conductivity can be used. At this time, the mixing ratio is preferably 5 to 95% by weight. In the polymer system, polymer materials such as polyaniline (PANI), polythiophene derivative (PEDOT), and poly (3-hexylthiophene) (P3HT) can be used. Further, the hole injection layer 5 may be a mixed layer or a stacked layer of these materials.

  The light emitting layer 6 contains a fluorescent material or phosphorescent material which is a compound having a light emitting function. Examples of such a fluorescent substance include at least one selected from compounds such as those disclosed in JP-A 63-264692, such as quinacridone, rubrene, and styryl dyes. Examples of phosphorescent substances include Appl. Phys. Lett. 75, 4 item, 1999, organic iridium complex, organic platinum complex and the like.

  As another embodiment, as shown in FIG. 3, the organic EL element 114 shown in FIG. 2 is used except that a hole transport layer 13A is inserted as an organic semiconductor layer between the hole injection layer 5 and the light emitting layer 6. There are identical elements. Examples of the material for the hole transport layer 13A include a triphenyldiamine derivative, a styrylamine derivative, an amine derivative having an aromatic condensed ring, a carbazole derivative, and examples of the polymer material include polyvinylcarbazole and derivatives thereof, polythiophene, and the like. Two or more of these compounds may be used in combination. Furthermore, in general, it is preferable to use an organic semiconductor material having a larger ionization potential Ip than the hole injection layer for the hole transport layer. Although not shown, a second hole transport layer is inserted as an organic semiconductor layer between the second hole injection layer 5b and the second light-emitting layer 6b in this embodiment, and an auxiliary electrode / insulating layer / anode / hole injection is inserted. A structure of layer / hole transport layer / light emitting layer / cathode / second light emitting layer / second hole transport layer / second hole injection layer / second anode / second insulating layer / second auxiliary electrode may be employed.

  Furthermore, as shown in FIG. 4, as another embodiment, the same element as the organic EL element 114 shown in FIG. 2 is used except that an electron injection layer 13B is inserted as an organic semiconductor layer between the light emitting layer 6 and the cathode 7. is there. Although not shown, an electron transport layer may be further provided between the electron injection layer and the light emitting layer in this embodiment. For the electron injection layer and / or the electron transport layer, quinoline derivatives, oxadiazole derivatives, perylene derivatives such as organometallic complexes having 8-quinolinol or a derivative thereof such as tris (8-quinolinolato) aluminum (Alq3) as a ligand Pyridine derivatives, pyrimidine derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives, and the like can be used. The electron injection layer and / or the electron transport layer may also serve as the light emitting layer 6. In such a case, it is preferable to use tris (8-quinolinolato) aluminum or the like. When the electron injection layer and the electron transport layer are formed by stacking, it is preferable to stack the compounds having the highest electron affinity values from the cathode 7 side. Although not shown, a second electron injection layer is further inserted as an organic semiconductor layer between the cathode 7 and the second light emitting layer 6b in this embodiment, and an auxiliary electrode / insulating layer / anode / hole injection layer / light emitting layer / electron. A structure of injection layer / cathode / second electron injection layer / second light emitting layer / second hole injection layer / second anode / second insulating layer / second auxiliary electrode may be employed.

  Furthermore, as shown in FIG. 5, as another embodiment, it is inserted between the anode 4 and the hole injection layer 5 and between the second anode 4b and the second hole injection layer 5b. There is the same element as the organic EL element 114 shown in FIG. 2 except that the carrier suppression layer BF is inserted. The carrier suppression layer BF defines a carrier supply portion CPP in which the anode 4 is in contact with the hole injection layer 5. In this case, the work function value of the carrier suppression layer BF is smaller than the work function value of the anode 4. In this case, the material of the carrier suppression layer BF is selected from those whose work function value is larger than the ionization potential value of the hole injection layer 5. In the present embodiment, a carrier suppression layer BF made of a metal material different from the metal material of the anode 4 is stacked on the anode 4, and the carrier path injected into the hole injection layer 5 is defined by the carrier suppression layer BF.

  Due to the carrier movement in the organic semiconductor, the carrier suppression layer BF is based on the condition of its ionization potential, that is, the value of the work function (or ionization potential) between the work function of the contact electrode and the ionization potential of the organic semiconductor layer. Selected. This is because it is better to have a large energy barrier to inhibit carrier movement.

  Specifically, the material of the carrier suppression layer BF used in the present embodiment is a hole injection material (hole injection layer 5) having an ionization potential Ip1 (eV) and an anode 4 having a work function Wf1 (eV). And a carrier suppression layer BF having a work function Wf2 (eV), Ip1 and Wf2 preferably have a relationship of Ip1> Wf2. The insertion of the carrier suppression layer BF becomes a barrier from the anode 4 to the organic semiconductor layer via the carrier suppression layer BF, and current hardly flows.

  At this time, it is desirable that Ip1 and Wf1 satisfy Ip1 <Wf1, but Ip1 ≧ Wf1 may be satisfied, and the difference between Ip1 and Wf1 may be within 0.5 eV. Although hole injection on the surface where the hole injection layer 5 and the anode 4 are in contact is not hindered, holes are injected on the surface where the hole injection layer and the carrier suppression layer BF are in contact due to the difference in work function. By suppressing the current component that does not depend on the voltage applied to the auxiliary electrode 2, it is possible to reduce the OFF current and improve the luminance ON / OFF ratio.

  Furthermore, as another embodiment, the same effect as described above can be obtained by having two light emitting layers sandwiching one anode with the anode as a common electrode. For example, as shown in FIG. 6, the organic EL element 114 has, as a basic portion, an auxiliary electrode 2 on a substrate 1 as a first auxiliary electrode, an insulating layer 3 as a first insulating layer, and a cathode 7 as a first cathode (first cathode). Electrode), the electron injection layer 13B as the first electron injection layer, the light emitting layer 6 as the first light emitting layer, the hole transport layer 13A as the first hole transport layer, and the hole injection layer 5 as the first hole injection layer. After the formation, the anode 4 (second electrode) is formed as a common electrode using a transparent conductive film, and then the second hole injection layer 5b, the second hole transport layer 13Ab, and the second light emission are formed on the base portion. The layer 6b, the second electron injection layer 13Bb, the second cathode 7b (third electrode), the second insulating layer 3b, and the second auxiliary electrode 2b are sequentially formed.

  Further, as another embodiment, an intermediate insulating film laminated on the second auxiliary electrode is provided, and a third light emitting layer sandwiched between a pair of electrodes formed on the intermediate insulating film is provided. By having the light emitting layer, the same effects as described above can be obtained. For example, as shown in FIG. 7, the organic EL element 114 is formed by forming an intermediate insulating film MIL on the second auxiliary electrode of the embodiment shown in FIG. The third insulating layer 3c, the third anode 4c, the third hole injection layer 5c, the third light emitting layer 6c, and the second cathode 7b are formed in this order, and a similar element structure can be repeated. At that time, one pixel can be formed by one element by using light emitting materials that emit red, green, and blue for the three light emitting layers.

  In the above embodiment, the insulating layer is provided only between the auxiliary electrode and the hole injection layer. However, an insulating film having substantially the same shape as the anode is formed on the anode to further reduce the leakage current between the anode and the cathode. It is good also as a structure to reduce.

  According to this embodiment, since one cathode or anode is shared and two light emitting layers are provided and can be driven independently, it can be obtained from one element without changing the size of the light emitting surface and the light emitting layer material. Maximum brightness can be improved. Further, by using materials that can obtain different emission colors for the two light emitting layer materials, effects such as increasing the number of colors that can be expressed by one element can be obtained.

  Further, by using the light emitting element of the embodiment, it is possible to reduce the number of devices arranged in one pixel when active matrix driving is performed, compared with an organic EL display device using polysilicon or the like. Cost reduction, low power consumption, and long life. Furthermore, since the light emission brightness is about twice that of the conventional structure, it can be driven at a low voltage when obtaining the same brightness as the conventional element, so the load on the element is light and the life can be extended. Become. In addition, since at least two light emitting layers are made of materials capable of emitting light of different wavelengths, two or more display colors can be obtained from one light emitting element, so that a light emitting display with many expression colors can be obtained without increasing the number of pixels. The device can be easily manufactured.

  Although the light-emitting element is described in the above embodiment, a plurality of light-emitting elements can be used for a pixel of a display device. Specifically, an active drive type display device according to the present invention can be realized if at least one organic transistor, a necessary element such as a capacitor, a pixel electrode, and the like are formed on a common substrate. As an example, a structure when applied to a display device will be described below.

  8 uses the organic EL element 114 shown in FIG. 2 in which the first and second anodes 4-4b are electrically connected and the first and second auxiliary electrodes 2-2b are also electrically connected. 1 is an equivalent circuit diagram showing a light emitting portion of a subpixel of an organic EL display panel.

  Each of the light emitting portions formed on the substrate includes a switching organic TFT element 111 as a selection transistor, a capacitor 113 for holding a data voltage, and an organic EL element 114. By arranging this configuration in the vicinity of each intersection of the scanning line SL, the power supply line VccL, and the signal line DL, a light emitting portion of the pixel can be realized. In this embodiment, the effect of omitting the driving transistor can be obtained, but the present invention can also be applied when two or more driving organic TFT elements are provided.

  A gate electrode G of the switching organic TFT element 111 is connected to a scanning line SL to which an address signal is supplied, and a source electrode S of the switching organic TFT element 111 is connected to a signal line DL to which a data signal is supplied. The drain electrode D of the switching organic TFT element 111 is connected to the first and second auxiliary electrodes 2-2b of the organic EL element 114 and one terminal of the capacitor 113. The cathode 7 of the organic EL element 114 is connected to the power supply line VccL, and the other of the capacitor 113 is grounded. The first and second anodes 4-4b of the organic EL element 114 are grounded.

  The scanning line SL on the substrate of the organic EL display panel, the gate electrode G of the switching organic TFT element 111, the first and second auxiliary electrodes 2-2b of the organic EL element 114, and the other terminal of the capacitor 113 are, for example, anodized. Possible conductor pattern. Oxide films generated by anodizing from these conductor patterns become insulating films and insulating layers on the respective conductor patterns.

  The organic TFT element 111 is laminated on the substrate of the organic EL display panel so that a channel can be formed between the opposing source electrode S and drain electrode D and the source electrode and drain electrode which are formed together with the organic EL element 114. An organic semiconductor film made of an organic semiconductor, and a gate electrode G that applies an electric field to the organic semiconductor film between the source electrode S and the drain electrode D, and further covers the gate electrode G to cover the source electrode S and the drain electrode A gate insulating film that insulates from D;

  FIG. 9 is a configuration diagram illustrating an organic EL display panel in which a plurality of light emitting units (organic EL elements 114) in FIG. 8 are arranged in a matrix and used for pixels. Each of the scanning lines SL is connected to a scanning line driver SLD, the signal line DL is connected to a data line driver DLD, and the power supply line VccL is connected to a power source.

  FIG. 10 shows that the first and second anodes 4-4b are electrically connected in the organic EL element 114 shown in FIG. 2 as another embodiment, but the first and second auxiliary electrodes 2, 2b are electrically connected. Fig. 2 shows an equivalent circuit diagram showing a light emitting portion of a subpixel of an organic EL display panel using one connected to a separate circuit.

  The gate electrodes of the switching organic TFT elements 111 and 111b are connected to the scanning line SL to which an address signal is supplied, and the source electrodes of the switching organic TFT elements 111 and 111b are connected to the signal lines DL and DLb, respectively. The drain electrodes of the switching organic TFT elements 111 and 111b are connected to the first and second auxiliary electrodes 2 and 2b of the organic EL element 114 and one terminal of the capacitors 113 and 113b, respectively. The cathode 7 of the organic EL element 114 is connected to the power supply line VccL, and the other of the capacitor 113 is grounded. The first and second anodes 4-4b of the organic EL element 114 are grounded.

  FIG. 11 is a configuration diagram showing an organic EL display panel in which a plurality of light emitting units (organic EL elements 114) of FIG. 10 are arranged in a matrix and used for pixels. Each of the scanning lines SL is connected to a scanning line driver SLD, the signal lines DL and DLb are connected to data line drivers DLD and DLDb, respectively, and the power supply line VccL is connected to a power source.

  In FIG. 12, the first, second, and third anodes 4-4b-4c are electrically connected in the organic EL element 114 shown in FIG. 7 as still another embodiment. 3 is an equivalent circuit diagram showing a light emitting portion of a sub-pixel of an organic EL display panel using a structure in which auxiliary electrodes 2, 2b and 2c are electrically connected to separate circuits.

  The gate electrodes of the switching organic TFT elements 111, 111b, and 111c are connected to a scanning line SL to which an address signal is supplied, and the source electrodes of the switching organic TFT elements 111, 111b, and 111c are connected to signal lines DL, DLb, and DLc, respectively. Has been. The drain electrodes of the switching organic TFT elements 111, 111b and 111c are connected to the first, second and third auxiliary electrodes 2, 2b and 2c of the organic EL element 114 and one terminal of the capacitors 113 and 113b, respectively. The cathode 7 of the organic EL element 114 is connected to the power supply line VccL, and the other of the capacitor 113 is grounded. The first, second and third anodes 4-4b-4c of the organic EL element 114 are grounded.

  FIG. 13 is a configuration diagram showing an organic EL display panel in which a plurality of light emitting units (organic EL elements 114) of FIG. 12 are arranged in a matrix and used for pixels. Each of the scanning lines SL is connected to a scanning line driver SLD, the signal lines DL, DLb, and DLc are connected to data line drivers DLD, DLDb, and DLDc, respectively, and the power supply line VccL is connected to a power source.

Example 1
A light emitting device as shown in FIG. 14 was manufactured. 14 is a plan view of the light emitting device of FIG. 2 viewed from the substrate side. As shown in FIG. 14, the first and second anodes 4-4 b are formed in a comb-like or saddle-like shape, but may be in a lattice-like shape, and the anode may be a lattice-like, comb-like or saddle-like shape. Thus, a pattern for carriers passing through the organic semiconductor layer can be defined.

  Further, auxiliary electrode / insulating layer / anode / hole injection layer / hole transport layer / light emitting layer / cathode / second light emitting layer / second hole transport layer / second hole injection layer / second anode / second A light emitting device having a configuration of insulating layer / second auxiliary electrode was manufactured.

  Such a light emitting device was manufactured by the following steps (1) to (13).

  (1) Formation of auxiliary electrode: After forming ITO to a thickness of 100 nm on a non-alkali glass substrate by a sputtering method, a photoresist is applied by spin coating. The previous photoresist was patterned by exposure and development using an optical mask, and the ITO film in the portion without the photoresist pattern was removed by milling, and finally the photoresist was dissolved using a stripping solution.

  (2) Formation of insulating layer: An insulating layer was formed to a thickness of 300 nm by spin coating using a polyvinylphenol polymer 8 wt% propylene glycol monomethyl ether acetate (PGMEA) solution. Thereafter, the polymer film formed on the end portion on the auxiliary electrode was wiped off with cotton containing PGMEA, and baked at 200 ° C. for 180 minutes using a hot plate.

  (3) Formation of anode: 50 nm of gold was deposited as an anode by a vacuum deposition method using a metal mask. The deposition rate of gold was 0.1 m / s. Subsequently, using the same mask, aluminum was deposited to a thickness of 10 nm by vacuum deposition. The film formation rate of aluminum at this time was 0.2 nm / s.

  (4) Formation of hole injection layer: Pentacene was deposited to a thickness of 50 nm as the hole injection layer. At this time, the film formation rate of pentacene was set to 0.1 nm / s.

  (5) Formation of hole transport layer: α-NPD was deposited to a thickness of 50 nm as the hole transport layer.

  (6) Formation of light-emitting layer: Tris (8-quinolinolato) aluminum was formed to 60 nm as a light-emitting layer material by vacuum deposition.

  (7) Formation of cathode: Silver was deposited as a cathode by 15 nm by vacuum deposition. At this time, the deposition rate of silver was set to 0.1 nm / s.

  (8) Formation of second light emitting layer: Tris (8-quinolinolato) aluminum was formed to a thickness of 60 nm by vacuum deposition as the second light emitting layer.

  (9) Formation of second hole transport layer: α-NPD was formed as the second hole transport layer.

  (10) Formation of second hole injection layer: As the second hole injection layer, pentacene was deposited to a thickness of 50 nm at a deposition rate of 0.1 nm / s.

  (11) Formation of second anode: As a second anode, a 20 nm thick aluminum film was formed using a metal mask and then a 20 nm thick gold film was formed by vacuum deposition. At this time, the metal mask was formed so that the film formation range was the same as that of the anode formed in the step (3), and was further electrically connected.

(12) Formation of the second insulating layer: A 200 nm thick SiO ₂ film was formed as the second insulating layer by vacuum evaporation using an electron beam.

  (13) Formation of second auxiliary electrode: Gold was deposited as a second auxiliary electrode by a vacuum deposition method. At this time, a metal mask was used to limit the film forming range, and the metal mask was formed so as to be electrically connected to the auxiliary electrode created in the step (1).

  All steps (3) to (13) were performed with a vacuum integrated device.

(Example 2)
Further, a light emitting element as shown in FIG. 15 was manufactured. 15 is a plan view of the light emitting device of FIG. 6 as viewed from the substrate side.

  The light emitting device shown in FIG. 6 was manufactured in the following steps (1) to (15).

  (1) Formation of auxiliary electrode: ITO was formed to 100 nm by sputtering on an alkali-free glass substrate, and then patterned in the same manner as in Example 1.

(2) Formation of insulating layer: 300 nm of SiO ₂ was formed as the insulating layer by sputtering. At this time, the deposition range was limited using a metal mask so that an insulating layer was not deposited on a part of the auxiliary electrode.

  (3) Fabrication of cathode: Magnesium and silver were co-deposited at a ratio of 10: 1 by vacuum deposition as a cathode. At this time, the deposition rate of magnesium was 1 nm / s, and the deposition rate of silver was 0.1 nm / s. Thereafter, 20 nm of platinum was deposited using the same mask.

(4) Formation ... electron injection layer of the electron injection layer, and the carbon film of fullerene C ₆₀ was deposited by vacuum evaporation.

  (5) Formation of light-emitting layer: Tris (8-quinolinolato) aluminum (Alq3) and rubrene were co-deposited as a light-emitting layer material by a vacuum evaporation method to form a film having a thickness of 40 nm. At this time, the concentration of rubrene was 3 wt%. The deposition rate of Alq3 was 0.3 nm / s.

  (6) Formation of hole transport layer: α-NPD was formed as a hole transport layer by vacuum deposition using a 50 nm metal mask.

  (7) Formation of hole injection layer: CuPc was formed as a hole injection layer by vacuum deposition using a 30 nm metal mask.

  (8) Formation of anode: Gold IZO was deposited as an anode by 30 nm by vacuum deposition.

  (9) Formation of second hole injection layer: A CuPc film having a thickness of 30 nm was formed as the second hole injection layer in the same manner as in (7).

  (10) Formation of second hole transport layer: α-NPD was deposited to a thickness of 50 nm as the second hole transport layer in the same manner as in the step (6).

  (11) Formation of second light-emitting layer: B-Alq3 was formed as a second light-emitting layer to a thickness of 30 nm by a vacuum evaporation method using a metal mask.

  (12) Formation of second electron injection layer: As the second electron injection layer, C60 was formed by vacuum evaporation in the same manner as in the step (4).

  (13) Formation of second cathode: As in the case of (3), a platinum film having a thickness of 20 nm was formed as the second cathode, and then magnesium and silver were co-evaporated to a thickness of 20 nm. At this time, the same metal mask as that used in the step (3) was used, and the metal mask was formed so as to be electrically connected to the cathode formed in the step (3).

(14) Formation of the second insulating layer: The SiO ₂ film having a thickness of 3200 nm was formed as the second insulating layer by vacuum evaporation using an electron beam.

  (15) Formation of second auxiliary electrode: Gold was deposited as a second auxiliary electrode by a vacuum deposition method. At this time, the metal mask was used to limit the film formation range so that there was no electrical connection with the auxiliary electrode created in step (1).

  In addition, all the processes of (3)-(15) were performed with the vacuum integrated apparatus.

It is a fragmentary sectional view which shows the conventional organic EL element. It is a fragmentary sectional view which shows the organic EL element of embodiment by this invention. It is a fragmentary sectional view which shows the organic EL element of other embodiment by this invention. It is a fragmentary sectional view which shows the organic EL element of other embodiment by this invention. It is a fragmentary sectional view which shows the organic EL element of other embodiment by this invention. It is a fragmentary sectional view which shows the organic EL element of other embodiment by this invention. It is a fragmentary sectional view which shows the organic EL element of other embodiment by this invention. It is an equivalent circuit diagram which shows the sub pixel light emission part of the organic electroluminescence display of other embodiment by this invention. FIG. 9 is a configuration diagram illustrating an organic EL display panel in which a plurality of light emitting units in FIG. 8 are arranged in a matrix and used for pixels. It is an equivalent circuit diagram which shows the sub pixel light emission part of the organic electroluminescence display of other embodiment by this invention. FIG. 11 is a configuration diagram illustrating an organic EL display panel in which a plurality of light emitting units in FIG. 10 are arranged in a matrix and used for pixels. It is an equivalent circuit diagram which shows the sub pixel light emission part of the organic electroluminescence display of other embodiment by this invention. FIG. 13 is a configuration diagram illustrating an organic EL display panel in which a plurality of light emitting units in FIG. 12 are arranged in a matrix and used for pixels. It is a fragmentary top view which shows the organic EL element of other embodiment by this invention. It is a fragmentary top view which shows the organic EL element of other embodiment by this invention. It is a fragmentary top view which shows the organic EL element of other embodiment by this invention.

Explanation of symbols

1 Substrate 2 Auxiliary electrode 3 Insulating layer 4 Anode 5 Organic semiconductor layer (hole injection layer)
6 Light emitting layer 7 Cathode 13A Hole transport layer 13B Electron injection layer 113 Capacitor 114 Organic EL element BF Carrier suppression layer DL Signal line SL Scan line VccL Power supply line

Claims (16)

A light emitting layer formed between first and second electrodes facing in parallel;
An organic semiconductor layer formed between the light emitting layer and the first electrode;
A light-emitting element comprising: an auxiliary electrode disposed on an opposite side of a surface of the first electrode facing the second electrode via an insulating layer;
A second auxiliary electrode disposed on the opposite side of the surface of the second electrode facing the first electrode through a second light emitting layer, a third electrode, a second organic semiconductor layer, and a second insulating layer is laminated. A light-emitting element having the structure described above.   The first electrode, the third electrode, and the second electrode are an anode and a cathode, and at least one of the organic semiconductor layer and the second organic semiconductor layer is a hole injection layer, a hole transport layer, or a laminate thereof. The light-emitting element according to claim 1.   An auxiliary organic semiconductor layer formed between at least one of the light emitting layer and the second electrode and between the second light emitting layer and the second electrode, the auxiliary organic semiconductor layer being an electron injection layer; The light emitting device according to claim 2, wherein the light emitting device is an electron transport layer or a laminate thereof.   The first electrode, the third electrode, and the second electrode are a cathode and an anode, and at least one of the organic semiconductor layer and the second organic semiconductor layer is an electron injection layer, an electron transport layer, or a laminate thereof. The light-emitting element according to claim 1.   An auxiliary organic semiconductor layer formed between at least one of the light emitting layer and the second electrode and between the second light emitting layer and the second electrode, the auxiliary organic semiconductor layer being a hole injection layer; The light emitting device according to claim 4, wherein the light emitting device is a hole transport layer or a laminate thereof.   The light emitting device according to any one of claims 1 to 5, wherein the first and third electrodes have a lattice shape, a comb shape, or a hook shape.   The light emitting device according to claim 1, wherein the second electrode is made of a transparent material or a translucent material.   The carrier deterring layer inserted in contact with at least one between the first and the organic semiconductor layers and between the third electrode and the second organic semiconductor layer. A light emitting device according to any one of the above.   The light emitting device according to claim 1, wherein the light emitting layer and the second light emitting layer are made of the same light emitting layer material.   The light emitting device according to claim 1, wherein the first and second light emitting layers are made of different light emitting layer materials.   The light emitting device according to claim 1, wherein the first and third electrodes are connected to each other.   The light emitting device according to claim 1, wherein the first and third electrodes are connected to different power sources. An intermediate insulating film laminated on the second auxiliary electrode; formed on the intermediate insulating film; and
A third light-emitting layer formed between the fourth and fifth electrodes facing in parallel;
A third organic semiconductor layer formed between the third light emitting layer and the fourth electrode;
13. The third auxiliary electrode disposed on a side opposite to the surface of the fourth electrode facing the fifth electrode with a third insulating layer interposed therebetween. 13. The light emitting element as described in.   The light emitting device according to claim 12, wherein the intermediate electrode and the fourth electrode, the fifth electrode, or the third auxiliary electrode on the side close to the intermediate insulating film are made of a transparent material or a semi-transparent material. A display device in which a plurality of light emitting units are arranged in a matrix,
Each of the light emitting portions includes a light emitting layer formed between first and second electrodes facing in parallel,
An organic semiconductor layer formed between the light emitting layer and the first electrode;
A light-emitting element comprising: an auxiliary electrode disposed on an opposite side of a surface of the first electrode facing the second electrode via an insulating layer;
A second auxiliary electrode disposed on the opposite side of the surface of the second electrode facing the first electrode through a second light emitting layer, a third electrode, a second organic semiconductor layer, and a second insulating layer is laminated. A display device having the structure described above.   Each of the light emitting units includes a switching element electrically connected to the auxiliary electrode, and includes a wiring for supplying power to the pair of electrodes and a wiring for applying on / off voltage information to the switching element. The display device according to claim 15.

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