JP2005235783A - Light emitting device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device and an electric appliance with low consumption power and a long service life. <P>SOLUTION: A manufacturing method for the light emitting device which has a light emitting element formed on both sides of an organic chemical compound film between a pair of electrodes. Specifically, the method applies a solution including a first organic chemical compound onto an electrode and forming a film of a second organic chemical compound by a vacuum evaporation method to heat it. By this method, the device is made low in consumption power and long in the service life. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light emitting device using an organic light emitting element having an anode, a cathode, and a film containing an organic compound that emits light by applying an electric field (hereinafter referred to as “organic compound film”). In particular, the present invention relates to a light-emitting device using an organic light-emitting element in which an organic compound film contains a polymer compound, a driving voltage is lower than that in the past, and the lifetime of the element is long, and a method for manufacturing the same. Note that the light emitting device in this specification refers to an image display device or a light emitting device using an organic light emitting element as a light emitting element. In addition, connectors with organic light-emitting elements such as anisotropic conductive film (FPC: Flexible Printed Circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) attached, printed on the end of TAB tape or TCP It is assumed that the light emitting device includes all modules provided with a wiring board or modules in which an IC (integrated circuit) is directly mounted on an organic light emitting element by a COG (Chip On Glass) method.

  An organic light emitting element is an element that emits light when an electric field is applied. The light emission mechanism is an excited state by recombining electrons injected from the cathode and holes injected from the anode at the emission center in the organic compound film by applying a voltage with the organic compound film sandwiched between the electrodes. It is said that this molecule emits light by releasing energy when the molecular exciton returns to the ground state (hereinafter referred to as “molecular exciton”).

  Note that the type of molecular exciton formed by the organic compound can be a singlet excited state or a triplet excited state. However, in this specification, both excited states contribute to light emission. .

  In such an organic light emitting device, the organic compound film is usually formed as a thin film having a thickness of less than 1 μm. In addition, since the organic light emitting element is a self-luminous element in which the organic compound film itself emits light, a backlight as used in a conventional liquid crystal display is not necessary. Therefore, it is a great advantage that the organic light emitting device can be manufactured to be extremely thin and light.

  For example, in an organic compound film of about 100 to 200 nm, the time from carrier injection to recombination is about several tens of nanoseconds considering the carrier mobility of the organic compound film. Even if the process from light emission to light emission is included, light emission occurs in the order of microseconds or less. Therefore, one of the features is that the response speed is very fast.

Furthermore, since the organic light emitting element is a carrier injection type light emitting element, it can be driven with a direct current voltage, and noise hardly occurs. Regarding the driving voltage, the thickness of the organic compound film is first made to be a uniform ultra-thin film of about 100 nm, and electrode materials that reduce the carrier injection barrier for the organic compound film are selected, and further a heterostructure (two-layer structure). In this case, sufficient luminance of 100 cd / m ² was achieved at 5.5V (Reference 1: CW Tang and SA VanSlyke, “Organic electroluminescent diodes”, Applied Physics Letters, vol. 51, No. 12, 913 -915 (1987)).

  Due to these thin, lightweight, high-speed response, and direct current low voltage driving characteristics, organic light-emitting devices are attracting attention as next-generation flat panel display devices. Further, since it is a self-luminous type and has a wide viewing angle, the visibility is relatively good, and it is considered effective as an element used for a display screen of a portable device.

  By the way, in the configuration of the organic light-emitting device shown in Document 1, first, as a method for reducing the carrier injection barrier, a low-work function and relatively stable Mg: Ag alloy is used for the cathode, and electron injection is performed. Increases sex. This makes it possible to inject a large amount of carriers into the organic compound film.

Furthermore, as the organic compound film, a single heterostructure in which a hole transport layer made of a diamine compound and an electron transport light-emitting layer made of tris (8-quinolinolato) aluminum (hereinafter referred to as “Alq ₃ ”) are stacked is applied. By doing so, the carrier recombination efficiency is dramatically improved. This is explained as follows.

For example, in the case of an organic light emitting device having only an Alq ₃ single layer, since Alq ₃ has an electron transporting property, most of the electrons injected from the cathode reach the anode without recombining with the holes and emit light. The efficiency of is very bad. That is, a material that can transport both electrons and holes in a balanced manner (hereinafter referred to as “bipolar material”) is used in order to efficiently emit light (or drive at a low voltage) in a single layer organic light emitting device. And Alq ₃ does not meet that requirement.

  However, if a single heterostructure as in Document 1 is applied, electrons injected from the cathode are blocked at the interface between the hole transport layer and the electron transporting light emitting layer and confined in the electron transporting light emitting layer. Therefore, carrier recombination is efficiently performed in the electron-transporting light-emitting layer, leading to efficient light emission.

  If the concept of such a carrier blocking function is developed, it becomes possible to control the carrier recombination region. As an example, by inserting a layer capable of blocking holes (hole blocking layer) between the hole transport layer and the electron transport layer, the holes are confined in the hole transport layer, and There is a report that succeeded in making one emit light. (Reference 2: Yasunori KIJIMA, Nobutoshi ASAI and Shin-ichiro TAMURA, “A Blue Organic Light Emitting Diode”, Japanese Journal of Applied Physics, Vol. 38, 5274-5277 (1999)).

  In addition, the organic light-emitting device in Document 1 can be said to be an idea of functional separation in which hole transport is performed by a hole transport layer, and electron transport and light emission are performed by an electron transport light-emitting layer. This concept of functional separation has further evolved into a double heterostructure (three-layer structure) in which a light emitting layer is sandwiched between a hole transport layer and an electron transport layer (Reference 3: Chihaya ADACHI, Shizuo TOKITO, Tetsuo). TSUTSUI and Shogo SAITO, "Electroluminescence in Organic Films with Three-Layered Structure", Japanese Journal of Applied Physics, Vol. 27, No. 2, L269-L271 (1988)).

  The advantage of such functional separation is that it is no longer necessary to have various functions (such as light-emitting properties, carrier transportability, and carrier injection properties from electrodes) at the same time due to the functional separation. Etc. (for example, it becomes unnecessary to search for a bipolar material forcibly). That is, a high light emission efficiency can be easily achieved by combining materials having good light emission characteristics and materials having excellent carrier transportability.

  Because of these advantages, the concept of the laminated structure (carrier blocking function or function separation) itself described in Document 1 has been widely used up to now.

  However, since the laminated structure as described above is a junction between different kinds of materials, an energy barrier always occurs at the interface. If an energy barrier exists, the movement of carriers at the interface is hindered, which raises the following two problems.

  The first is that it becomes an obstacle to further reducing the drive voltage. In fact, in the current organic light-emitting device, the driving voltage is superior to the device with a single layer structure using a conjugated polymer, and the top data in power efficiency (unit: [lm / W]) (however, singlet) (Reference 4: Tetsuo Tsutsui, Journal of the Japan Society of Applied Physics, Organic Molecules and Bioelectronics, Vol. 11, No. 1, P. 8) (2000)).

  Note that the conjugated polymer described in Document 4 is a bipolar material, and the carrier recombination efficiency can achieve a level equivalent to that of the laminated structure. Therefore, if the recombination efficiency of carriers can be made equal without using a laminated structure, such as by using a bipolar material, a single layer structure with fewer interfaces actually shows a lower drive voltage. Yes.

For example, at the interface with the electrode, there is a method of inserting a material that relaxes the energy barrier and increasing the carrier injection property to reduce the driving voltage (Reference 5: Takeo Wakimoto, Yoshinori Fukuda, Kenichi Nagayama, Akira Yokoi). , Hitoshi Nakada, and Masami Tsuchida, "Organic EL Cells Using Alkaline Metal Compounds as Electron Injection Materials", IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 44, NO. 8, 1245-1248 (1997)). In Reference 5, the driving voltage is successfully reduced by using Li ₂ O as the electron injection layer.

  However, the carrier mobility between organic materials (for example, between the hole transport layer and the light-emitting layer, hereinafter referred to as “organic interface”) is still an unsolved field, and has a low monolayer structure. This is an important point for catching up with the driving voltage.

  Furthermore, as another problem caused by the energy barrier, the influence on the device lifetime of the organic light emitting device can be considered. That is, the movement of carriers is hindered and the brightness is reduced due to the accumulation of charges.

  Although no clear theory has been established regarding this degradation mechanism, the luminance can be reduced by inserting a hole injection layer between the anode and the hole transport layer, and using rectangular wave ac drive instead of dc drive. (Ref. 6: SA VanSlyke, CH Chen, and CW Tang, "Organic electroluminescent devices with improved stability", Applied Physics Letters, Vol. 69, No. 15, 2160-2162 (1996) )). This can be said to be experimental support that the reduction in luminance could be suppressed by eliminating charge accumulation by inserting the hole injection layer and ac driving.

  From the above, the laminated structure has the advantage that the carrier recombination efficiency can be easily increased, and the material selection range can be widened from the viewpoint of functional separation, while the carrier structure can be increased by creating many organic interfaces. It can be said that the movement is hindered and the driving voltage and the luminance are lowered.

  Therefore, in the present invention, by fabricating an element having a concept different from that of a conventionally used stacked structure, the energy barrier existing in the organic compound film is relaxed to improve carrier mobility, and at the same time, Similar to the functional separation, it is an object to develop the functions of various materials (hereinafter referred to as “functional expression”). Accordingly, an object of the present invention is to provide an organic light emitting device having a lower driving voltage and a longer device life than the conventional one.

  It is another object of the present invention to provide a light-emitting device that has a lower driving voltage and a longer lifetime by using such an organic light-emitting element. Furthermore, it is an object of the present invention to provide an electric appliance that uses the light-emitting device to produce an electric appliance that has lower power consumption than the conventional one and that can be maintained for a long time.

  Regarding the relaxation of the energy barrier in the laminated structure, it is noticeable in the technique of inserting the carrier injection layer as shown in Document 5. An explanation using an energy band diagram is shown in FIG. 1 by taking the hole injection layer as an example.

  In FIG. 1A, the anode 101 and the hole transport layer 102 are directly joined, but in this case, the energy barrier 104 between the anode 101 and the hole transport layer 102 is large. However, a material having a HOMO level located between the ionization potential of the anode and the highest occupied molecular orbital (hereinafter referred to as “HOMO”) level of the hole transport layer is inserted as the hole injection layer 103. As a result, the energy barrier can be designed stepwise (FIG. 1 (b)).

  By designing a step-like energy barrier as shown in FIG. 1B, the carrier injection property from the electrode can be improved, and the drive voltage can be lowered to some extent. However, the problem is that by increasing the number of layers, the number of organic interfaces increases conversely. This is considered to be the reason why the single layer structure holds the top data of the driving voltage and power efficiency as shown in Document 4.

  In other words, by overcoming this point, while taking advantage of the laminated structure (a variety of materials can be combined and no complicated molecular design is required), the driving voltage and power efficiency of the single layer structure can be achieved. I can catch up.

  Therefore, the present inventor substantially eliminates the interface in the organic compound film and relaxes the energy barrier in the organic compound film in the organic compound film containing two or more types (one or more of which are high molecular compounds) of the organic compound. A method was devised.

That is, the organic compound film is a hole injecting compound that receives holes from the anode, an electron injecting compound that receives electrons from the cathode, a hole transporting compound, an electron transporting compound, and blocking holes or electrons. In the case of containing at least two compounds selected from the group consisting of a blocking compound capable of emitting light and a luminescent compound exhibiting light emission, a region where the at least two compounds are mixed (hereinafter referred to as “mixed region”) is provided. This is a method of substantially eliminating the interface in the organic compound film. Hereinafter, this method is referred to as mixed bonding.

  The reason why the polymer compound is used in the present invention is that the polymer compound generally has a higher carrier mobility and can be driven at a lower voltage. That is, it is a feature of the present invention that mixed bonding is performed in a system using a polymer compound.

  In this case, the hole injecting compound, the electron injecting compound, the hole transporting compound, and the electron transporting compound may have a function of exhibiting light emission. In addition, the light emitting compound may have both carrier transportability and carrier injection property, or may be a material with poor carrier transportability.

  The mixed region is preferably formed at a position away from the anode and the cathode. One reason is to relax the barrier by setting the interface in the organic compound film as a mixed region while retaining the regions capable of expressing each function such as carrier injection, carrier transport, and light emission.

  In particular, when the mixed region has a light emitting function, it is necessary to keep the mixed region away from the electrode and away from the electrode in order to prevent quenching by the electrode (hereinafter referred to as “quenching”). In that case, it is preferable to separate the mixed region from the electrode by 20 nm or more in consideration of diffusion of molecular excitons. As for the degree of the separation distance, the most efficient distance may be selected in consideration of the carrier balance.

  By the way, when such a mixed junction is formed, a method of doping a guest into the mixed region is also conceivable. In the mixed region, since the carrier movement is considered to be lubrication, it is preferable to use a light-emitting compound that emits light as a guest.

  By performing the mixed bonding as described above, an organic light-emitting element capable of exhibiting a function without showing a clear laminated structure (that is, without a clear organic interface) can be manufactured.

  In the organic compound film containing the first organic compound and the second organic compound different from the first organic compound, the first organic compound and the second organic compound are When providing the mixed area | region which is mixing, when a 1st organic compound and a 2nd organic compound are both high molecular compounds, one side may be a low molecular compound. Furthermore, a method of giving a continuous density change in the mixed region is still more preferable. Hereinafter, these methods are referred to as “continuous bonding”. In this case, the mixed region is particularly referred to as “continuous bonding region”.

  A conceptual diagram of a conventional laminated structure and continuous bonding according to the present invention is shown in FIG. FIG. 2A shows a conventional laminated structure (single heterostructure). That is, it has an organic compound film 203a composed of the first organic compound 201 and the second organic compound 202, and is formed of a laminated structure (or a layer formed from the first organic compound layer 201a and the second organic compound layer 202a). A clear organic interface). In this case, it can be seen that there is no region where the concentration of the first organic compound 201 and the concentration of the second organic compound 202 gradually change, and the regions are discontinuous (that is, the concentration is 0 at the organic interface). % To 100%, or 100% to 0%).

  However, in the case of the continuous junction of the present invention (FIG. 2B), a region in which the concentration of the first organic compound 201 and the concentration of the second organic compound 202 are gradually changed in the organic compound film 203b (that is, Since there is a continuous junction region 204b), there is no clear organic interface. However, since there is a region where the first organic compound can express the function (first functional region 201b) and a region where the second organic compound can express the function (second functional region 202b), the function of each material is expressed. it can.

  By performing the continuous bonding as described above, an organic light-emitting element capable of exhibiting a function without showing a clear laminated structure (that is, without a clear organic interface) can be manufactured.

  By the way, the first organic compound and the second organic compound preferably have different functions from the viewpoint of the concept of the present invention (that is, the functions of various materials are expressed without using a laminated structure). .

  In this case, if both the first organic compound and the second organic compound are high molecular compounds, a configuration in which one emits light and the other exhibits a carrier transport function is conceivable. Further, when the second organic compound is a low molecular compound, the low molecular compound exhibits light emission, the high molecular compound exhibits a carrier transport function, and the high molecular compound exhibits light emission. The structure which expresses a carrier transport function can be considered.

  Furthermore, when the high molecular compound exhibits a carrier transport function, the high molecular compound is a high molecular compound containing π electrons (that is, a conductive high molecular compound), and further, chemical doping is performed on the high molecular compound. It is preferable to improve conductivity.

  The polymer compound used as the hole transporting compound is preferably a polythiophene derivative, a polyaniline derivative, a polyvinyl carbazole derivative, or the like, and the polymer compound used as the light emitting compound is a polyphenylene derivative, a polyparaphenylene vinylene derivative, Polydialkylfluorene derivatives and the like are preferable.

  Further, when performing the mixed bonding (including continuous bonding) as described above, a method of adding the function of the guest by adding a third organic compound as a guest in the mixed region can be considered. From the viewpoint of function expression, it is preferable to use a light-emitting compound exhibiting light emission as a guest. This is because the first organic compound and the second organic compound forming the mixed region have carrier transport property or blocking property, and a light-emitting compound is added to the mixed region, so that the carrier recombination rate is increased. This is because the light emission efficiency is considered to increase.

  The conceptual diagram is shown in FIG. In FIG. 3A, an organic compound film 303 containing a first organic compound and a second organic compound is provided on a substrate 301 between an anode 302 and a cathode 304, and the mixed region 305 emits light. Compound 306 was added to obtain a light emitting region.

  In recent years, from the viewpoint of luminous efficiency, organic light-emitting devices capable of converting energy emitted when returning from a triplet excited state to a ground state (hereinafter referred to as “triplet excited energy”) into light emission are high in that. It attracts attention because of its luminous efficiency (Reference 7: DF O'Brien, MA Baldo, ME Thompson and SR Forrest, "Improved energy transfer in electrophosphorescent devices", Applied Physics Letters, vol. 74, No. 3, 442-444 ( 1999)) (Reference 8: Tetsuo TSUTSUI, Moon-Jae YANG, Masayuki YAHIRO, Kenji NAKAMURA, Teruichi WATANABE, Taishi TSUJI, Yoshinori FUKUDA, Takeo WAKIMOTO and Satoshi MIYAGUCHI, "High Quantum Efficiency in Organic Light-Emitting Devices with Iridium-Complex as a Triplet Emissive Center ", Japanese Journal of Applied Physics, Vol. 38, L1502-L1504 (1999)).

  Document 7 uses a metal complex having platinum as the central metal, and Document 8 uses a metal complex having iridium as the central metal. An organic light-emitting device that can convert these triplet excitation energy into light emission (hereinafter referred to as “triplet light-emitting device”) can achieve higher luminance emission and higher emission efficiency than conventional ones.

However, according to the report example of Document 8, the half-life of the luminance when the initial luminance is set to 500 cd / m ² is about 170 hours, and there is a problem in the device life. Therefore, by applying the present invention to a triplet light-emitting element, it is possible to realize a very high-performance light-emitting element in which the lifetime of the element is long in addition to high luminance light emission and high light emission efficiency by light emission from a triplet excited state. .

  Accordingly, a case where a material capable of converting triplet excitation energy into light emission is selected as the third organic compound that is a guest and added to the mixed region is also included in the present invention.

  What is considered as the third organic compound is not necessarily limited to the light-emitting compound that emits light. In particular, when the first organic compound or the second organic compound emits light, as the third organic compound, the highest occupied molecular orbital compared to the first organic compound and the second organic compound. It is preferable to use a compound having a large energy difference between (HOMO) and the lowest unoccupied molecular orbital (LUMO) (that is, a compound capable of blocking carriers and molecular excitons). By this method, in the mixed region formed by the first organic compound and the second organic compound, it is possible to increase the recombination rate of carriers and increase the light emission efficiency.

  The conceptual diagram is shown in FIG. In FIG. 3 (b), an organic compound film 303 containing a first organic compound and a second organic compound is provided on the substrate 301 between the anode 302 and the cathode 304, and carriers and A compound (blocking compound) 307 capable of blocking molecular excitons was added.

  In FIG. 3B, a light-emitting region in which a light-emitting compound 306 that emits light is further added to the mixed region 305 is also provided. That is, this is a form in which the technique using a light-emitting compound that emits light as the third organic compound (FIG. 3A) and the addition of a blocking compound are combined. Here, since the compound 307 capable of blocking carriers and molecular excitons is on the cathode side of the luminescent compound 306 exhibiting light emission, the compound 307 capable of blocking carriers and molecular excitons should be of a hole blocking property. That's fine.

  As compounds capable of blocking carriers and molecular excitons, phenanthroline derivatives, oxadiazole derivatives, triazole derivatives, and the like are conceivable.

  By the way, it is considered that elemental analysis by SIMS is an important technique when the mixed region as described above is specified. In particular, in the case of continuous bonding, as can be seen from the conceptual diagram shown in FIG. 2, it is considered that a significant difference appears compared to the conventional laminated structure.

  Therefore, among the elements constituting the first organic compound or the second organic compound, a region in which the detected amount of the element that can be detected by SIMS continuously changes in the direction from the anode to the cathode. The light emitting device having the above is included in the present invention.

  In addition, a high molecular compound containing a Group 15 element or a Group 16 element is generally used in an organic light emitting device, and a compound containing a Group 17 element is chemically doped to improve the conductivity of the high molecular compound. Sometimes. Therefore, by forming a continuous junction region from a material containing a Group 15 element to a Group 17 element and a material not containing it, the concentration change can be observed more remarkably. Nitrogen, phosphorus, oxygen, sulfur, fluorine, chlorine, bromine, iodine, etc. are the mainstream as the Group 15 element to Group 17 element.

  Furthermore, when a third organic compound is added as a guest to the mixed region, a metal complex may be used as a compound serving as the guest, particularly a light-emitting compound that emits light.

  Therefore, the third organic compound is a metal complex having a metal element, and the detection region of the metal element that can be detected by SIMS is a region containing both the first organic compound and the second organic compound (that is, mixed). The light emitting device which is the region) is also included in the present invention. As the metal element, aluminum, zinc, or beryllium is mainly used. Further, when the third organic compound is a light-emitting compound that emits light from a triplet excited state, iridium and platinum can be detected because iridium and platinum are mainly used as metal complexes.

  By implementing the present invention as described above, it is possible to provide a light emitting device having a driving voltage lower than that of a conventional device and having a long lifetime. Furthermore, by producing an electric appliance using the light emitting device, it is possible to provide an electric appliance that consumes less power than the conventional one and is kept long.

  By implementing the present invention, a light-emitting device with low power consumption and excellent lifetime can be obtained. Furthermore, by using such a light-emitting device for a light source or a display portion, it is possible to obtain an electric appliance that is bright and consumes little power and is kept long.

  Below, the form at the time of implementing this invention is described. Note that an organic light-emitting element only needs to have at least one of an anode and a cathode transparent in order to extract light emission, but in this embodiment, the element structure is such that a transparent anode is formed on a substrate and light is extracted from the anode. Describe. Actually, a structure for extracting light from the cathode and a structure for extracting light from the side opposite to the substrate are also applicable to the present invention.

  In carrying out the present invention, a manufacturing process for forming a mixed region or a continuous bonding region is important. The inventor has devised a process for forming a mixed region or a continuous junction region in an organic compound film containing a polymer compound. Therefore, here, a method for manufacturing the organic light emitting device disclosed in the present invention will be described.

  In the conventional process (when a laminated structure is formed by wet coating), for example, the first solution in which the first organic compound is dissolved is applied, and the solvent contained in the first solution is completely removed by heating or the like. After that, the second organic compound dissolved in the solution in which the first organic compound does not elute is formed, so that a clear organic interface is generated.

  For example, an aqueous solution of polyethylene dioxythiophene (hereinafter referred to as “PEDOT”) doped with polystyrene sulfonic acid (hereinafter referred to as “PSS”) is formed by spin coating, and is heated at 100 ° C. or higher under atmospheric pressure. After removing water completely, a cross-sectional TEM photograph of an organic compound film obtained by spin-coating a toluene solution of polyparaphenylene vinylene (hereinafter referred to as “PPV”) having an alkoxyl group and then drying again by heating. Is shown in FIG. As is clear from FIG. 4, the conventional process results in a laminated structure that produces a clear organic interface.

  The present inventor has devised five manufacturing methods as a process for solving this problem and forming the mixed region or the concentration changing region. Hereinafter, the embodiment will be described in the case of an organic compound film containing two kinds of organic compounds, which is the simplest example.

  The first manufacturing method is shown in FIG. First, a first solution 503a in which a first organic compound (polymer compound) is dissolved is wet-coated on a substrate 501 (FIG. 5 (a)) provided with an electrode 502 (FIG. 5 (b)). Next, as a step 511 for forming a mixed region or a continuous bonding region, heating is performed at a temperature at which the vapor pressure of the solvent contained in the first solution is equal to or lower than the atmospheric pressure of the working atmosphere (FIG. 5 (c)). The second solution 504 in which the second organic compound is dissolved is wet-applied in a state 503b in which the solvent contained in the solution remains (FIG. 5 (d)). Finally, all of the solvent is removed by heating 512 to obtain the organic compound film of the present invention having a mixed region or continuous bonding region 505.

  Next, the second manufacturing method is shown in FIG. First, a first solution 603a in which a first organic compound (polymer compound) is dissolved is wet-coated on a substrate 601 provided with an electrode 602 (FIG. 6A). Next, the first organic compound film 603b is formed by completely removing the solvent contained in the first solution 603a by heating 611 (FIG. 6B). Further, as a step 612 for forming a mixed region or a continuous joining region, an elution region 603c is formed by placing the solvent contained in the first solution in the working atmosphere (FIG. 6 (c)). The second solution 604 in which the two organic compounds are dissolved is wet-applied (FIG. 6 (d)). Finally, all the solvent is removed by heating 613 to obtain the organic compound film of the present invention having the mixed region or continuous bonding region 605.

  As a third manufacturing method, a mixed region or a continuous bonding region can be formed using a low molecular compound that can be dry-formed as the first organic compound. That is, after the first organic compound film 603b is formed by vacuum deposition or the like (that is, in the state shown in FIG. 6B), the second organic compound is dissolved in a solvent that can slightly dissolve the first organic compound. (Polymer compound) is wet-coated to form the state of FIG. 6 (d).

  Furthermore, although it is a 4th manufacturing method, in FIG. 6, a low molecular weight compound can also be used as a 1st organic compound. That is, first, the first organic compound film 603b is formed by a vacuum deposition method or the like to form the state of FIG. 6B, and a solvent capable of dissolving the first organic compound is placed in a working atmosphere. Thus, the elution region 603c is formed (FIG. 6C).

  By the way, the first to fourth manufacturing methods described above are all made of a polymer material wet-coated by the second organic compound. On the other hand, as a fifth manufacturing method, a polymer material is first wet-coated as a first organic compound, and a low molecular compound is vacuum-deposited as a second organic compound, and then a mixed region or a continuous bonding region is formed. The inventor also devised a method of forming.

  In the fifth technique, a solution in which a first organic compound (polymer compound) is dissolved is wet-applied to a substrate having electrodes, and then transferred into a vacuum chamber, and then a second organic compound (low molecule). This is a method of forming a mixed region or a concentration changing region by forming a film of the compound) by vacuum vapor deposition and then heating to diffuse the second organic compound (low molecular weight compound). The heating temperature may be a temperature at which the solvent in which the first organic compound is dissolved can be completely removed.

In the fifth method, a method in which heating is performed under a reduced pressure of 10 ⁻⁴ Pascal is further preferable. In this case, the heating temperature is preferably about 60 ° C to 100 ° C.

  With respect to the wet coating method described above, various methods are possible, and an alternate adsorption method and an ink jet method are conceivable in addition to commonly used wet film forming methods such as spin coating and dip coating. In particular, the inkjet method is capable of patterning organic compounds with high accuracy and can be patterned over a wide range, so it is an effective method for creating high-definition, large-area light-emitting devices. It is considered to be.

  FIG. 7 shows a conceptual diagram for realizing the first manufacturing method by the ink jet method. First, a bank structure 706 is formed on a substrate 701 having an electrode 702 (FIG. 7A) by photolithography (FIG. 7B). Next, the first solution 703a in which the first organic compound (polymer compound) is dissolved is wet-coated by the inkjet printer head 721a (FIG. 7 (c)). Furthermore, as a step 711 for forming a mixed region or a continuous bonding region, heating is performed at a temperature lower than the temperature at which the vapor pressure of the solvent contained in the first solution 703a becomes the atmospheric pressure of the working atmosphere (FIG. 7 (d)). Then, in a state 703b where the solvent contained in the first solution remains, the second solution 704 in which the second organic compound is dissolved is wet-applied by the inkjet printer head 721b (FIG. 7 (e)). Finally, all the solvent is removed by heating to obtain the organic compound film of the present invention having a mixed region or a continuous bonding region.

  For example, when using a compound that emits light as the second organic compound, full-color light emission is achieved by coating each pixel 707a to 707c with a compound that exhibits red, green, and blue colors using the inkjet printer head 721b. A device can be made.

  By the manufacturing method as described above, the mixed region or the continuous bonding region disclosed in the present invention can be formed.

  In this example, an organic light-emitting element manufactured by applying the method shown in FIG. 5 in the embodiment of the invention is specifically illustrated.

  First, indium tin oxide (hereinafter referred to as “ITO”) is formed on a glass substrate by sputtering to a thickness of about 100 nm to form an anode. Next, an aqueous solution of PEDOT doped with PSS as a hole transporting material is formed on the anode by spin coating.

  Here, as shown in FIG. 5, the substrate is heated at a temperature lower than the temperature at which the vapor pressure of water becomes atmospheric pressure (100 ° C.), and the water in the aqueous PEDOT solution remains slightly. Further, an alkoxyl group-substituted PPV using toluene as a solvent (hereinafter referred to as “MEH-PPV”) is formed by spin coating, and the solvent is completely removed by heating to 100 ° C. or higher.

  Finally, 400 nm of ytterbium is deposited as a cathode by vacuum deposition to obtain the organic light emitting device of the present invention that emits green light derived from MEH-PPV.

In this example, an organic light-emitting element manufactured by applying the method shown in FIG. 6 in the embodiment of the invention is specifically illustrated.

  First, ITO is deposited on the glass substrate 601 by sputtering to a thickness of about 100 nm to form an anode 602. Next, an aqueous solution of PEDOT doped with PSS as a hole transporting material is formed on the anode by spin coating, and the solvent (water) is completely removed by heating at 150 ° C. for 10 minutes.

  Here, as shown in FIG. 6, polydioctylfluorene (hereinafter referred to as “PDOF”) using xylene as a solvent is formed by spin coating in an atmosphere containing water vapor, and then heated to 100 ° C. or higher. To completely remove water and xylene.

  Finally, calcium is vacuum-deposited to 100 nm as a cathode, and then aluminum is deposited to 150 nm to obtain an organic light-emitting device of the present invention that emits blue light derived from PDOF.

  In this example, an organic light-emitting device manufactured by applying a technique in which a low molecular compound is formed by vacuum deposition and then a high molecular compound dissolved in a solvent in which the low molecular compound is slightly dissolved is applied. Illustratively.

  First, indium tin oxide (hereinafter referred to as “ITO”) is formed on a glass substrate by sputtering to a thickness of about 100 nm to form an anode. Next, 4, 4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenyl-amino] -triphenylamine (hereinafter referred to as “MTDATA”) is used as a hole transporting material. A film is formed on the anode by vacuum deposition.

  Here, a solution in which a PPV precursor soluble in a polar solvent is dissolved in ethanol is formed into a film by spin coating. Thereafter, by heating to 80 ° C. or higher, the solvent is completely removed and at the same time the PPV is polymerized.

  Finally, ytterbium is deposited as a cathode by vacuum deposition at 400 nm to obtain the organic light-emitting device of the present invention that emits green light derived from PPV.

  In this example, an organic light-emitting element manufactured by applying an inkjet method is specifically illustrated.

  First, ITO 702 is formed on the glass substrate 701 by sputtering to a thickness of about 100 nm, and a bank structure 706 is formed by photolithography (FIG. 7B). Next, an aqueous solution 703a of PEDOT doped with PSS as a hole transporting material is formed on the anode by an inkjet printer head 721a, and the solvent (water) is completely removed by heating at 150 ° C. for 10 minutes. . The PEDOT 703a formed in this way is hardly dissolved in water and is only slightly eluted.

  Here, an ink using an aqueous solution 704 in which a water-soluble PPV precursor is dissolved is formed into a film by the ink jet printer head 721b, and then heated to 100 ° C. or higher to completely remove water and xylene.

  Finally, calcium is vacuum-deposited as a cathode to 100 nm and then aluminum is deposited to 150 nm to obtain an organic light-emitting device of the present invention that emits green light derived from PPV.

In this example, a solution in which a first organic compound (polymer compound) is dissolved is wet-applied to a substrate having electrodes, and then transported into a vacuum chamber, and then a second organic compound (low molecular compound). The second organic compound (low molecular compound) is diffused by vacuum deposition and then heated to diffuse the mixed region or continuous junction region, thereby emitting light in the mixed region or continuous junction region. An example in which an organic light-emitting element doped with a compound (here, a compound exhibiting light emission from a triplet excited state) is specifically illustrated. At this time, the heating temperature may be a temperature at which the solvent in which the first organic compound is dissolved can be completely removed. Furthermore, it is more preferable to perform the heating under a reduced pressure of about 10 ⁻⁴ Pascal.

  First, indium tin oxide (hereinafter referred to as “ITO”) is formed on a glass substrate by sputtering to a thickness of about 100 nm to form an anode. Next, since polyvinyl carbazole (hereinafter referred to as “PVK”) is used as the hole transporting material, a chloroform solution of PVK is formed by spin coating, and the solvent is removed by heating. Thereafter, since a solution using the same solvent (chloroform) is coated, it is desirable to perform this film formation several times in order to increase the film thickness to some extent.

Next, a solution obtained by adding 5 wt% of a bis (2-phenylpyridine) -acetylacetonatoiridium (hereinafter referred to as “Ir (ppy) ₂ (acac)”) complex, which is a triplet light emitting material, to a chloroform solution of PVK. Is prepared, and a film is formed by spin coating on the previously formed PVK film.

Here, without heating the substrate, tris (8-quinolinolato) aluminum (hereinafter referred to as “Alq ₃ ”), which is an electron transport material, is vacuum-deposited under a reduced pressure of 10 ⁻³ Pascal. Thereafter, by baking at 80 ° C. under a reduced pressure of 10 ⁻⁴ Pascal, a region having PVK and Alq ₃ as a host and Ir (ppy) ₂ (acac) as a guest (in the mixed region of PVK and Alq ₃ is Ir (ppy) ₂ (acac-doped region) can be formed.

Finally, an Al: Li alloy is deposited as a cathode at 150 nm by vacuum deposition to obtain the organic light emitting device of the present invention that emits green light derived from Ir (ppy) ₂ (acac).

  In this example, a light-emitting device including the organic light-emitting element disclosed in the present invention will be described. FIG. 8 is a cross-sectional view of an active matrix light emitting device using the organic light emitting element of the present invention. Note that although a thin film transistor (hereinafter referred to as “TFT”) is used here as an active element, a MOS transistor may be used.

  Further, although a top gate TFT (specifically, a planar TFT) is exemplified as the TFT, a bottom gate TFT (typically an inverted staggered TFT) can also be used.

  In FIG. 8, reference numeral 801 denotes a substrate. Here, a substrate that transmits visible light is used. Specifically, a glass substrate, a quartz substrate, a crystallized glass substrate, or a plastic substrate (including a plastic film) may be used. Note that the substrate 801 includes an insulating film provided on a surface.

  A pixel portion 811 and a drive circuit 812 are provided over the substrate 801. First, the pixel portion 811 will be described.

  The pixel portion 811 is an area for displaying an image. There are a plurality of pixels on the substrate, and each pixel has a TFT (hereinafter referred to as “current control TFT”) 802 for controlling the current flowing through the organic light emitting element, a pixel electrode (anode) 803, an organic compound film 804 and a cathode 805 are provided. Although only the current control TFT is shown in FIG. 8, a TFT (hereinafter referred to as “switching TFT”) for controlling the voltage applied to the gate of the current control TFT is provided.

  Here, the current control TFT 802 is preferably a p-channel TFT. Although an n-channel TFT can be used, when a current control TFT is connected to the anode of the organic light emitting element as shown in FIG. 8, the p-channel TFT can reduce power consumption. However, the switching TFT may be an n-channel TFT or a p-channel TFT.

  A pixel electrode 803 is electrically connected to the drain of the current control TFT 802. In this embodiment, since a conductive material having a work function of 4.5 to 5.5 eV is used as the material of the pixel electrode 803, the pixel electrode 803 functions as an anode of the organic light emitting element. As the pixel electrode 803, typically, indium oxide, tin oxide, zinc oxide, or a compound thereof (ITO or the like) may be used. An organic compound layer 804 is provided on the pixel electrode 803.

  Further, a cathode 805 is provided on the organic compound layer 804. As a material for the cathode 805, it is desirable to use a conductive material having a work function of 2.5 to 3.5 eV. As the cathode 805, a conductive film containing an alkali metal element or an alkalinity metal element, a conductive film containing aluminum, or a stack of aluminum or silver over the conductive film may be used.

  In addition, a layer including the pixel electrode 803, the organic compound layer 804, and the cathode 805 is covered with a protective film 806. The protective film 806 is provided to protect the organic light emitting device from oxygen and water. As a material for the protective film 806, silicon nitride, silicon nitride oxide, aluminum oxide, tantalum oxide, or carbon (specifically, diamond-like carbon) is used.

  Next, the drive circuit 812 will be described. The drive circuit 812 is an area for controlling the timing of signals (gate signal and data signal) transmitted to the pixel portion 811 and includes a shift register, a buffer, a latch, an analog switch (transfer gate), or a level shifter. In FIG. 8, a CMOS circuit including an n-channel TFT 807 and a p-channel TFT 808 is shown as a basic unit of these circuits.

  The circuit configuration of the shift register, buffer, latch, analog switch (transfer gate) or level shifter may be a known one. In FIG. 8, the pixel portion 811 and the drive circuit 812 are provided over the same substrate, but an IC or LSI can be electrically connected without providing the drive circuit 812.

  In FIG. 8, the pixel electrode (anode) 803 is electrically connected to the current control TFT 802, but a structure in which the cathode is connected to the current control TFT can also be adopted. In that case, the pixel electrode may be formed using a material similar to that of the cathode 805, and the cathode may be formed using a material similar to that of the pixel electrode (anode) 803. In that case, the current control TFT is preferably an n-channel TFT.

  Incidentally, although the light emitting device shown in FIG. 8 is manufactured in the process of forming the wiring 809 after the pixel electrode 803 is formed, in this case, the pixel electrode 803 may cause surface roughness. . Since the organic light-emitting element is a current-driven element, the characteristics may be deteriorated due to surface roughness of the pixel electrode 803.

  Therefore, as shown in FIG. 9, a light-emitting device in which the pixel electrode 903 is formed after the wiring 909 is formed is also conceivable. In this case, it is considered that the current injection property from the pixel electrode 903 is improved as compared with the structure of FIG.

  In FIGS. 8 and 9, each pixel installed in the pixel portion 811 or 911 is separated by a positive tapered bank-like structure 810 or 910. By making this bank-like structure into, for example, a reverse taper type structure, it is possible to adopt a structure in which the bank-like structure does not contact the pixel electrode. An example is shown in FIG.

  In FIG. 10, a wiring and separation unit 1010 that also serves as a separation unit using wiring is provided. As shown in FIG. 10, the shape of the wiring and separation portion 1010 (structure with eaves) is formed by laminating a metal constituting the wiring and a material having a lower etch rate than the metal (for example, metal nitride), and etching. Can be formed. With this shape, it is possible to prevent the pixel electrode 1003 and the wiring and the cathode 1005 from being short-circuited. In FIG. 10, unlike a normal active matrix light-emitting device, the cathode 1005 on the pixel has a stripe shape (similar to a passive matrix cathode).

  Here, an appearance of the active matrix light-emitting device shown in FIG. 9 is shown in FIG. FIG. 11 (a) shows a top view, and FIG. 11 (b) shows a cross-sectional view of FIG. 11 (a) taken along PP ′. Also, the reference numerals in FIG. 9 are cited.

  In FIG. 11A, reference numeral 1101 denotes a pixel portion, 1102 denotes a gate signal side driving circuit, and 1103 denotes a data signal side driving circuit. Signals transmitted to the gate signal side drive circuit 1102 and the data signal side drive circuit 1103 are input from a TAB (Tape Automated Bonding) tape 1105 through the input wiring 1104. Although not shown, instead of the TAB tape 1105, a TCP (Tape Carrier Package) provided with an IC (integrated circuit) may be connected to the TAB tape.

  At this time, reference numeral 1106 denotes a cover material provided above the organic light emitting device shown in FIG. 9, and is bonded by a sealing material 1107 made of resin. Any material may be used for the cover material 1106 as long as it does not transmit oxygen and water. In this embodiment, as shown in FIG. 11B, the cover material 1106 includes a plastic material 1106a, a carbon film (specifically, a diamond-like carbon film) 1106b provided on the front and back surfaces of the plastic material 1106a, 1106c.

  Further, as shown in FIG. 11 (b), the sealing material 1107 is covered with a sealing material 1108 made of resin so that the organic light emitting element is completely enclosed in the sealed space 1109. The sealed space 1109 may be filled with an inert gas (typically nitrogen gas or a rare gas), a resin, or an inert liquid (for example, liquid fluorinated carbon typified by perfluoroalkane). It is also effective to provide a hygroscopic agent or oxygen scavenger.

  Further, a polarizing plate may be provided on the display surface (the surface on which an image is observed) of the light emitting device shown in this embodiment. This polarizing plate has an effect of suppressing reflection of light incident from the outside and preventing an observer from being reflected on the display surface. Generally, a circularly polarizing plate is used. However, in order to prevent light emitted from the organic compound layer from being reflected by the polarizing plate and returning to the inside, it is preferable to adjust the refractive index so that the structure has less internal reflection.

  Note that any of the organic light-emitting elements disclosed in the present invention may be used as the organic light-emitting element included in the light-emitting device of this example.

  In this example, an active matrix light-emitting device is illustrated as an example of a light-emitting device including the organic light-emitting element disclosed in the present invention. Unlike Example 6, on the side opposite to the substrate on which the active element is formed. 1 shows a light emitting device having a structure for extracting light from a light source (hereinafter referred to as “upward emission”). FIG. 19 shows a cross-sectional view thereof.

  Note that although a thin film transistor (hereinafter referred to as “TFT”) is used here as an active element, a MOS transistor may be used. Further, although a top gate TFT (specifically, a planar TFT) is exemplified as the TFT, a bottom gate TFT (typically an inverted staggered TFT) can also be used.

  In this embodiment, the substrate 1901, the current control TFT 1902 formed in the pixel portion, and the drive circuit 1912 may have the same configuration as that of the sixth embodiment.

  Although the first electrode 1903 connected to the drain of the current control TFT 1902 is used as the anode in this embodiment, it is preferable to use a conductive material having a higher work function. Typical examples include metals such as nickel, palladium, tungsten, gold, and silver. In this embodiment, it is preferable that the first electrode 1903 does not transmit light, but in addition, it is more preferable to use a material having high light reflectivity.

  An organic compound layer 1904 is provided on the first electrode 1903. Further, a second electrode 1905 is provided on the organic compound layer 1904, which is a cathode in this embodiment. In that case, as the material of the second electrode 1905, it is desirable to use a conductive material having a work function of 2.5 to 3.5 eV. Typically, a conductive film containing an alkali metal element or alkalinity metal element, a conductive film containing aluminum, or a stack of aluminum or silver over the conductive film may be used. However, since the present embodiment uses upward emission, it is a major premise that the second electrode 1905 is light transmissive. Therefore, when these metals are used, an ultrathin film of about 20 nm is preferable.

  In addition, a layer including the first electrode 1903, the organic compound layer 1904, and the second electrode 1905 is covered with a protective film 1906. The protective film 1906 is provided to protect the organic light emitting device from oxygen and water. In this embodiment, any material that transmits light may be used.

  In FIG. 19, the first electrode (anode) 1903 is electrically connected to the current control TFT 1902; however, a structure in which the cathode is connected to the current control TFT may be employed. In that case, the first electrode may be formed of a cathode material and the second electrode may be formed of an anode material. At this time, the current control TFT is preferably an n-channel TFT.

  Further, reference numeral 1907 denotes a cover material, which is bonded by a sealing material 1908 made of resin. The cover material 1907 may be any material that does not transmit oxygen and water and that transmits light. In this embodiment, glass is used. The sealed space 1909 may be filled with an inert gas (typically nitrogen gas or a rare gas), a resin, or an inert liquid (for example, liquid fluorinated carbon typified by perfluoroalkane). It is also effective to provide a hygroscopic agent or an oxygen scavenger.

  Signals transmitted to the gate signal side drive circuit and the data signal side drive circuit are input from a TAB (Tape Automated Bonding) tape 1914 through the input wiring 1913. Although not shown, instead of the TAB tape 1414, a TCP (Tape Carrier Package) in which an IC (integrated circuit) is provided on the TAB tape may be connected.

  Further, a polarizing plate may be provided on the display surface (the surface on which an image is observed) of the light emitting device shown in this embodiment. This polarizing plate has an effect of suppressing reflection of light incident from the outside and preventing an observer from being reflected on the display surface. Generally, a circularly polarizing plate is used. However, in order to prevent light emitted from the organic compound layer from being reflected by the polarizing plate and returning to the inside, it is preferable to adjust the refractive index to have a structure with little internal reflection.

  Note that any of the organic light-emitting elements disclosed in the present invention may be used as the organic light-emitting element included in the light-emitting device of this example.

    In this example, a passive matrix light-emitting device is illustrated as an example of a light-emitting device including the organic light-emitting element disclosed in the present invention. FIG. 12A shows a top view, and FIG. 12B shows a cross-sectional view of FIG. 12A taken along PP ′.

  In FIG. 12A, reference numeral 1201 denotes a substrate, and here a plastic material is used. Plastic materials include polyimide, polyamide, acrylic resin, epoxy resin, PES (polyether sulfone), PC (polycarbonate), PET (polyethylene terephthalate) or PEN (polyether nitrile) in the form of a plate or film Can be used.

  Reference numeral 1202 denotes a scanning line (anode) made of an oxide conductive film. In this embodiment, an oxide conductive film obtained by adding gallium oxide to zinc oxide is used. Reference numeral 1203 denotes a data line (cathode) made of a metal film. In this embodiment, a bismuth film is used. Reference numeral 1204 denotes a bank made of acrylic resin, which functions as a partition for dividing the data line 1203. A plurality of scanning lines 1202 and data lines 1203 are both formed in stripes, and are provided so as to be orthogonal to each other. Although not shown in FIG. 12A, an organic compound layer is sandwiched between the scanning line 1202 and the data line 1203, and the intersection 1205 becomes a pixel.

  The scanning line 1202 and the data line 1203 are connected to an external drive circuit via the TAB tape 1207. Reference numeral 1208 represents a wiring group formed by aggregating the scanning lines 1202, and 1209 represents a wiring group formed by a set of connection wirings 1206 connected to the data line 1203. Further, although not shown, instead of the TAB tape 1207, a TCP provided with an IC on the TAB tape may be connected.

  In FIG. 12B, reference numeral 1210 denotes a sealing material, and reference numeral 1211 denotes a cover material bonded to the plastic material 1201 by the sealing material 1210. As the sealing material 1210, a photo-curing resin may be used, and a material with low degassing and low hygroscopicity is desirable. The cover material is preferably the same material as that of the substrate 1201, and glass (including quartz glass) or plastic can be used. Here, a plastic material is used.

  Next, an enlarged view of the structure of the pixel region is shown in FIG. Reference numeral 1213 denotes an organic compound layer. As shown in FIG. 12C, the bank 1204 has a shape in which the width of the lower layer is narrower than the width of the upper layer, and the data line 1203 can be physically divided. In addition, the pixel portion 1214 surrounded by the sealing material 1210 has a structure in which the organic compound layer is prevented from being deteriorated by being blocked from the outside air by a sealing material 1215 made of resin.

  The light-emitting device of the present invention having the above structure can be manufactured by a very simple process because the pixel portion 1214 is formed of the scanning line 1202, the data line 1203, the bank 1204, and the organic compound layer 1213. .

  Further, a polarizing plate may be provided on the display surface (the surface on which an image is observed) of the light emitting device shown in this embodiment. This polarizing plate has an effect of suppressing reflection of light incident from the outside and preventing an observer from being reflected on the display surface. Generally, a circularly polarizing plate is used. However, in order to prevent light emitted from the organic compound layer from being reflected by the polarizing plate and returning to the inside, it is preferable to adjust the refractive index so that the structure has less internal reflection.

Note that any of the organic light-emitting elements disclosed in the present invention may be used as the organic light-emitting element included in the light-emitting device of this example.

  In this embodiment, an example in which a printed wiring board is provided in the light emitting device shown in Embodiment 8 to form a module is shown.

  In the module shown in FIG. 13A, a TAB tape 1304 is attached to a substrate 1301 (here, including a pixel portion 1302, wirings 1303a and 1303b), and a printed wiring board 1305 is attached via the TAB tape 1304. Yes.

  Here, a functional block diagram of the printed wiring board 1305 is shown in FIG. In the printed wiring board 1305, at least ICs functioning as I / O ports (input or output units) 1306 and 1309, a data signal side driving circuit 1307, and a gate signal side circuit 1308 are provided.

  In this specification, a module having a configuration in which a TAB tape is attached to a substrate having a pixel portion formed on the substrate surface and a printed wiring plate having a function as a drive circuit is attached via the TAB tape is described in this specification. In particular, it will be called a drive circuit external module.

  Note that any of the organic light-emitting elements disclosed in the present invention may be used as the organic light-emitting element included in the light-emitting device of this example.

  In this embodiment, an example in which a printed wiring board is provided in the light emitting device shown in Embodiment 6, 7, or 8 and modularized is shown.

  In the module shown in FIG. 14A, a TAB tape 1405 is attached to a substrate 1401 (including a pixel portion 1402, a data signal side driving circuit 1403, a gate signal side driving circuit 1404, and wirings 1403a and 1404a). A printed wiring board 1406 is attached via a TAB tape 1405. A functional block diagram of the printed wiring board 1406 is shown in FIG.

  As shown in FIG. 14B, at least ICs functioning as I / O ports 1407 and 1410 and a control unit 1408 are provided inside the printed wiring board 1406. Although the memory unit 1409 is provided here, it is not always necessary. The control unit 1408 is a part having a function for controlling a drive circuit, correction of video data, and the like.

  A module having a configuration in which a printed wiring board having a function as a controller is attached to a substrate on which an organic light emitting element is formed is specifically referred to as a controller external module in this specification.

  Note that any of the organic light-emitting elements disclosed in the present invention may be used as the organic light-emitting element included in the light-emitting device of this example.

  In this example, an example of a light-emitting device in which the organic light-emitting element disclosed in the present invention is driven at a constant voltage by digital time gradation display is shown.

  FIG. 17A shows a circuit configuration of a pixel using an organic light emitting element. Tr represents a transistor, and Cs represents a storage capacitor. In the circuit configuration in FIG. 17A, the source line is connected to the source side of the transistor Tr1, and the gate line is connected to the gate of the transistor Tr1. The power supply line is connected to the storage capacitor Cs and the source side of the transistor Tr2. Since the anode of the organic light emitting element of the present invention is connected to the drain side of the transistor Tr2, the opposite side of the transistor Tr2 across the organic light emitting element is a cathode.

In this circuit, when a gate line is selected, a current flows from the source line to Tr1, and a voltage corresponding to the signal is accumulated in Cs. Then, a current controlled by the voltage (V _gs ) between the gate and source of Tr2 flows in Tr2 and the organic light emitting element.

After Tr1 is selected, Tr1 is turned off and the Cs voltage (V _gs ) is maintained. Therefore, it is possible to continue flowing a current that depends on V _gs .

  FIG. 17B shows a chart for driving such a circuit by digital time gray scale display. That is, one frame is divided into a plurality of subframes. In FIG. 17B, a 6-bit gradation is used to divide one frame into six subframes (SF1 to SF6). TA is the write time. In this case, the ratio of each sub-frame light emission period is 32: 16: 8: 4: 2: 1 as shown in the figure.

  An outline of the TFT substrate driving circuit in this embodiment is shown in FIG. In the substrate configuration in FIG. 17 (c), the power supply line and the cathode as shown in FIG. 17 (a) are connected to the pixel portion in which the organic light emitting device of the present invention is used as each pixel. The shift register is connected to the pixel portion in the order of shift register → latch 1 → latch 2 → pixel portion. A digital signal is input to the latch 1, and image data can be sent to the pixel portion by a latch pulse input to the latch 2.

  Since the gate driver and source driver are provided on the same substrate, and the pixel circuit and driver are designed to be digitally driven, a uniform image can be obtained without being affected by variations in TFT characteristics. it can.

  In this embodiment, an example of an active matrix type constant current driving circuit which is driven by passing a constant current through the organic light emitting element disclosed in the present invention is shown. The circuit configuration is shown in FIG.

  A pixel 1810 illustrated in FIG. 18 includes a signal line Si, a first scanning line Gj, a second scanning line Pj, and a power supply line Vi. The pixel 1810 includes Tr1, Tr2, Tr3, Tr4, a mixed junction organic light emitting element 1811, and a storage capacitor 1812.

  The gates of Tr3 and Tr4 are both connected to the first scanning line Gj. One of the source and drain of Tr3 is connected to the signal line Si, and the other is connected to the source of Tr2. One of the source and drain of Tr4 is connected to the source of Tr2, and the other is connected to the gate of Tr1. That is, one of the source and drain of Tr3 and one of the source and drain of Tr4 are connected.

  The source of Tr1 is connected to the power supply line Vi, and the drain is connected to the source of Tr2. The gate of Tr2 is connected to the second scanning line Pj. The drain of Tr2 is connected to the pixel electrode of the organic light emitting element 1811. The organic light emitting element 1811 includes a pixel electrode, a counter electrode, and an organic light emitting layer provided between the pixel electrode and the counter electrode. A constant voltage is applied to the counter electrode of the organic light emitting element 1811 by a power source provided outside the light emitting panel.

  Note that Tr3 and Tr4 may be either n-channel TFTs or p-channel TFTs. However, Tr3 and Tr4 have the same polarity. Tr1 may be either an n-channel TFT or a p-channel TFT. Tr2 may be either an n-channel TFT or a p-channel TFT. One of the pixel electrode and the counter electrode of the light-emitting element is an anode, and the other is a cathode. When Tr2 is a p-channel TFT, it is desirable to use the anode as the pixel electrode and the cathode as the counter electrode. Conversely, when Tr2 is an n-channel TFT, it is desirable to use the cathode as the pixel electrode and the anode as the counter electrode.

The storage capacitor 1812 is formed between the gate and source of Tr1. The storage capacitor 1812 is provided in order to more reliably maintain the voltage (V _GS ) between the gate and the source of Tr1, but it is not always necessary to provide it.

  In the pixel shown in FIG. 18, the current supplied to the signal line Si is controlled by a current source included in the signal line driver circuit.

 By applying the circuit configuration as described above, it is possible to perform a constant current drive in which a constant current is supplied to the organic light emitting element to keep the luminance constant. Although the organic light emitting device having the mixed region disclosed in the present invention has a longer life than the conventional organic light emitting device, it is effective because the life can be further extended by performing constant current driving as described above. It is.

  The light-emitting device of the present invention described in the above embodiment has an advantage of low power consumption and long life. Therefore, an electric appliance in which the light-emitting device is included as a display unit or the like is an electric appliance that can operate with lower power consumption than the conventional one and that can be maintained for a long time. In particular, an electric appliance such as a portable device that uses a battery as a power source is extremely useful because low power consumption is directly linked to convenience (battery is unlikely to run out).

  Further, since the light-emitting device is a self-luminous type, a backlight like a liquid crystal display device is not necessary, and the thickness of the organic compound layer is less than 1 μm, so that it can be thin and light. Therefore, an electric appliance in which the light emitting device is included as a display unit or the like is an electric appliance that is thinner and lighter than conventional ones. This is also extremely useful because it is directly connected to convenience (lightness and compactness when carrying), especially with respect to electric appliances such as portable devices. Furthermore, there is no doubt that the thinness (not bulky) of electrical appliances in general is also useful from the viewpoint of transportation (capable of mass transportation) and installation (serving space such as rooms).

  Note that since the light-emitting device is a self-luminous type, the light-emitting device is superior in visibility in a bright place as compared with a liquid crystal display device and has a wide viewing angle. Therefore, an electric appliance having the light-emitting device as a display portion has a great merit in terms of easy viewing.

  That is, the electric appliance using the light emitting device of the present invention is extremely useful because it has the advantages of low power consumption and long life in addition to the advantages of the conventional organic light emitting elements such as thin and light weight and high visibility.

  In this embodiment, an electric appliance including the light emitting device of the present invention as a display portion is illustrated. Specific examples thereof are shown in FIGS. 15 and 16. In addition, any of the elements disclosed in the present invention may be used as the organic light-emitting element included in the electric appliance of this example. Moreover, any form of FIGS. 8-14 may be used for the form of the light-emitting device contained in the electric appliance of a present Example.

  FIG. 15A shows a display using an organic light emitting element, which includes a housing 1501a, a support base 1502a, and a display portion 1503a. By manufacturing a display using the light-emitting device of the present invention as the display portion 1503a, a thin and light display that can be kept long can be realized. Therefore, transportation becomes simple, space saving during installation is possible, and the service life is also long.

  FIG. 15B shows a video camera, which includes a main body 1501b, a display unit 1502b, an audio input unit 1503b, operation switches 1504b, a battery 1505b, and an image receiving unit 1506b. By manufacturing a video camera using the light-emitting device of the present invention as the display portion 1502b, a lightweight video camera with low power consumption can be realized. Therefore, the consumption of the battery is reduced and the carrying becomes easy.

  FIG. 15C illustrates a digital camera, which includes a main body 1501c, a display unit 1502c, an eyepiece unit 1503c, and an operation switch 1504c. By manufacturing a digital camera using the light-emitting device of the present invention as the display portion 1502c, a lightweight digital camera with low power consumption can be realized. Therefore, the consumption of the battery is reduced and the carrying becomes easy.

  FIG. 15D shows an image reproducing device provided with a recording medium, which is a main body 1501d, a recording medium (CD, LD, DVD, etc.) 1502d, an operation switch 1503d, a display unit (A) 1504d, and a display unit (B) 1505d. including. The display portion (A) 1504d mainly displays image information, and the display portion (B) 1505d mainly displays character information. By producing the image reproducing device using the light emitting device of the present invention as the display unit (A) 1504d and the display unit (B) 1505d, the image reproducing device that has low power consumption and is kept light and long. realizable. Note that the image reproducing device provided with the recording medium includes a CD reproducing device, a game machine, and the like.

  FIG. 15E illustrates a portable (mobile) computer, which includes a main body 1501e, a display portion 1502e, an image receiving portion 1503e, an operation switch 1504e, and a memory slot 1505e. By manufacturing a portable computer using the light-emitting device of the present invention as the display portion 1502e, a thin and light portable computer with low power consumption can be realized. Therefore, the consumption of the battery is reduced and the carrying becomes easy. The portable computer can record information on a recording medium in which flash memory or nonvolatile memory is integrated, and can reproduce the information.

  FIG. 15F shows a personal computer, which includes a main body 1501f, a housing 1502f, a display portion 1503f, and a keyboard 1504f. By manufacturing a personal computer using the light-emitting device of the present invention as the display portion 1503f, a thin and lightweight personal computer with low power consumption can be realized. In particular, when a portable application such as a notebook computer is required, it is a great advantage in terms of battery consumption and lightness.

  In addition, the electric appliances often display information distributed through an electronic communication line such as the Internet or wireless communication such as radio waves, and in particular, opportunities for displaying moving image information are increasing. The response speed of the organic light emitting device is very fast, and it is suitable for such moving image display.

  Next, FIG. 16A shows a mobile phone, which includes a main body 1601a, an audio output unit 1602a, an audio input unit 1603a, a display unit 1604a, an operation switch 1605a, and an antenna 1606a. By manufacturing a mobile phone using the light-emitting device of the present invention as the display portion 1604a, a thin and lightweight mobile phone with low power consumption can be realized. Therefore, the battery consumption is reduced, the carrying becomes easier and the body can be made compact.

  FIG. 16B shows an audio device (specifically, an on-vehicle audio), which includes a main body 1601b, a display portion 1602b, and operation switches 1603b and 1604b. By manufacturing an acoustic device using the light-emitting device of the present invention as the display portion 1602b, a lightweight acoustic device with low power consumption can be realized. In the present embodiment, in-vehicle audio is shown as an example, but it may be used for home audio.

  In addition, in the electric appliances as shown in FIGS. 15 to 16, the light emission luminance is modulated according to the brightness of the usage environment by further incorporating a light sensor and providing means for detecting the brightness of the usage environment. It is effective to have such a function. The user can recognize the image or the character information without any problem if the brightness of 100 to 150 can be secured in the contrast ratio as compared with the brightness of the usage environment. That is, when the usage environment is bright, it is possible to increase the brightness of the image for easy viewing, and when the usage environment is dark, the brightness of the image can be suppressed to reduce power consumption.

  Various electric appliances using the light-emitting device of the present invention as a light source can be said to be very useful because they can operate with low power consumption and can be thin and light. Typically, an electrical appliance including the light-emitting device of the present invention as a light source such as a backlight or a front light of a liquid crystal display device or a light source of a lighting device can achieve low power consumption and be thin and lightweight.

  Therefore, even when the display units of the electric appliances of FIGS. 15 to 16 shown in this embodiment are all liquid crystal displays, the electric appliances using the light emitting device of the present invention as the backlight or front light of the liquid crystal display. By producing a thin, lightweight electric appliance with low power consumption can be achieved.

The figure which shows the role of a positive hole injection layer. The figure which shows the structure of an organic light emitting element. The figure which shows the structure of an organic light emitting element. The figure which shows the cross-sectional TEM photograph of an organic compound film | membrane. 3A and 3B illustrate a method for manufacturing an organic compound film. 3A and 3B illustrate a method for manufacturing an organic compound film. 3A and 3B illustrate a method for manufacturing an organic compound film. The figure which shows the cross-section of a light-emitting device. The figure which shows the cross-section of a light-emitting device. The figure which shows the cross-section of a light-emitting device. 3A and 3B illustrate a top structure and a cross-sectional structure of a light-emitting device. 3A and 3B illustrate a top structure and a cross-sectional structure of a light-emitting device. FIG. 6 illustrates a structure of a light-emitting device. FIG. 6 illustrates a structure of a light-emitting device. The figure which shows the specific example of an electric appliance. The figure which shows the specific example of an electric appliance. FIG. 11 illustrates a circuit configuration of a light-emitting device. FIG. 11 illustrates a circuit configuration of a light-emitting device. The figure which shows the cross-section of a light-emitting device.

Claims (6)

A solution containing the first organic compound is applied onto the electrode by an inkjet method,
Forming a second organic compound by vacuum deposition,
A method for manufacturing a light-emitting device, comprising heating. A solution containing a polymer compound is applied onto the electrode by an inkjet method,
A low molecular weight compound is formed into a film by vacuum deposition,
A method for manufacturing a light-emitting device, comprising heating. Apply a solution containing a hole transporting material on the anode by an inkjet method,
A film of an electron transporting material is formed by vacuum deposition,
A method for manufacturing a light-emitting device, comprising heating. Applying a solution containing polyvinyl carbazole on the anode by an inkjet method,
Tris (8-quinolinolato) aluminum was formed by vacuum deposition,
A method for manufacturing a light-emitting device, comprising heating. A first solution containing a hole transporting material is applied onto the anode by an inkjet method,
A second solution containing the hole transporting material, the luminescent material, and the solvent is applied by an inkjet method,
A film of an electron transporting material is formed by vacuum deposition,
A method for manufacturing a light-emitting device, comprising heating. Forming a thin film transistor on an insulating surface;
A solution containing the first organic compound is applied to the electrode electrically connected to the thin film transistor by an inkjet method,
Forming a second organic compound by vacuum deposition,
A method for manufacturing a light-emitting device, comprising heating.

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