JP2013207010A - Light-emitting element, manufacturing method therefor, display device and luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting element of low drive voltage having excellent view angle characteristics, in which short circuit does not take place between a first electrode and a second electrode, even if a particle (foreign matter) or a protrusion exists on the first electrode.SOLUTION: The light-emitting element is constituted by laminating a first electrode 12, an organic layer 13 including a luminous layer 13a composed of an organic light-emitting material, a first resistive layer 14, a second resistive layer 15 composed of a material having an electrical resistivity lower than that of a material composing the first resistive layer 14, and a second electrode 16, sequentially on a substrate 11. One of the first electrode 12 and second electrode 16 reflects light from the luminous layer 13a, and the other transmits the light from the luminous layer 13a. Total thickness of the first resistive layer 14 and second resistive layer 15 is 1 μm or more.

Description

  The present disclosure relates to a light-emitting element, a method for manufacturing a light-emitting element, a display device, and an illumination device, and in particular, a light-emitting element using electroluminescence of an organic material, a method for manufacturing the same, and a display device and an illumination using the light-emitting element. Relates to the device.

  In recent years, organic EL display devices using organic electroluminescence (EL) elements have attracted attention as display devices that can replace liquid crystal display devices. This organic EL display device is self-luminous, has low power consumption, and is considered to be sufficiently responsive to high-definition high-speed video signals. The development and commercialization for practical use are being promoted.

  The organic EL element usually has a structure in which a first electrode, an organic layer including a light emitting layer made of an organic light emitting material, and a second electrode are sequentially laminated (see, for example, Patent Document 1).

  A short circuit between the electrodes is one of the major issues in the practical application of such an organic EL element. That is, according to the knowledge of the present inventor, if particles (foreign matter) or protrusions exist on the first electrode, the coverage of the organic layer formed on the first electrode is not perfect, When the second electrode is formed, a short circuit may occur between the first electrode and the second electrode. For example, as shown in FIG. 19, when the foreign matter 203 exists on the first electrode 202 formed on the substrate 201, the coverage of the organic layer 204 is remarkably deteriorated in the portion of the foreign matter 203. For this reason, when the second electrode 205 is formed, the second electrode 205 comes into contact with the first electrode 202 in the vicinity of the contact portion between the first electrode 202 and the foreign matter 203, thereby causing a short circuit.

  As described above, when a short circuit occurs between the first electrode and the second electrode, in the active matrix type organic EL display device, the pixel in which the short circuit occurs is defective, and the display of the organic EL display device is performed. It will degrade the quality. Moreover, in the passive matrix type organic EL display device, when this short circuit occurs, a broken line occurs, and the display quality of the organic EL display device is deteriorated. This problem becomes a significant problem particularly in a large organic EL display device. This is because the number of allowable defects per unit area is reduced in a large organic EL display device.

  So far, various efforts have been made to reduce the short circuit between the first electrode and the second electrode. For example, Patent Document 2 discloses a technique of inserting a high resistance layer between an anode electrode and an organic layer in a bottom emission type organic EL display device. Japanese Patent Application Laid-Open No. H10-228707 discloses a technique for forming a high-resistance layer in the top emission type organic EL display device with two anode electrodes and forming an anode electrode close to the organic layer. Patent Document 4 discloses a technique in which a cathode electrode has two layers in a bottom emission type organic EL display device, and a layer constituting an anode electrode close to the organic layer has a high resistance. Further, Patent Document 5 discloses a technique for inserting a high resistance layer between an organic layer and a second electrode in a top emission type organic EL display device.

International Publication No. 01/039554 Pamphlet JP 2001-35667 A JP 2006-338916 A JP 2005-209647 A JP 2010-56075 A

  However, when the short circuit between the first electrode and the second electrode is prevented by the techniques disclosed in Patent Documents 2 to 5, there is a problem in the viewing angle characteristics of chromaticity and luminance of the organic EL display device There is. That is, the organic EL element is generally affected by interference and resonance due to the structure of the organic layer and the electrode when light generated from the light emitting layer is transmitted to the outside. Due to the influence of these interferences and resonances, the viewing angle dependence of chromaticity and luminance occurs. That is, as the viewing angle increases, there may be a problem that the shape of the spectrum of the light from the organic EL display device varies greatly or the light intensity decreases significantly. Therefore, it is desirable to keep the influence of interference as low as possible. In order to reduce the influence of interference, the pitch of interference can be reduced by increasing the distance between the first electrode and the second electrode. However, in the techniques disclosed in Patent Documents 2 to 5, since the thickness and electrical resistivity of each layer are defined in order to prevent a short circuit between the first electrode and the second electrode, The distance between the two electrodes cannot be arbitrarily separated. Moreover, since the resistance increases when the thickness of the high resistance layer is increased, the driving voltage of the organic EL element is significantly increased, and the characteristics of the element are deteriorated.

  Therefore, the problem to be solved by the present disclosure is that even if particles (foreign matter) or protrusions exist on the first electrode, a short circuit does not occur between the first electrode and the second electrode, and the viewing angle A light-emitting element having good characteristics and low driving voltage and a method for manufacturing the light-emitting element.

  Another problem to be solved by the present disclosure is to provide a high-quality display device using the above-described excellent light-emitting element and having good viewing angle characteristics.

  Still another problem to be solved by the present disclosure is to provide an illumination device that uses the above-described excellent light-emitting element and has less angle dependency and good light distribution characteristics.

In order to solve the above problems, the present disclosure provides:
A first electrode;
An organic layer including a light emitting layer made of an organic light emitting material on the first electrode;
A first resistive layer on the organic layer;
A second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer on the first resistance layer;
A second electrode on the second resistance layer;
One of the first electrode and the second electrode reflects light from the light emitting layer, and the other of the first electrode and the second electrode transmits light from the light emitting layer,
In the light-emitting element, the total thickness of the first resistance layer and the second resistance layer is 1 μm or more.

In addition, this disclosure
Forming a first electrode on a substrate;
Forming an organic layer including a light emitting layer made of an organic light emitting material on the first electrode;
Sequentially forming a first resistance layer and a second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer on the organic layer;
Forming a second electrode on the second resistance layer,
One of the first electrode and the second electrode reflects light from the light emitting layer, and the other of the first electrode and the second electrode transmits light from the light emitting layer,
In this method, the total thickness of the first resistance layer and the second resistance layer is 1 μm or more.

In addition, this disclosure
A first electrode;
An organic layer including a light emitting layer made of an organic light emitting material on the first electrode;
A first resistive layer on the organic layer;
A second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer on the first resistance layer;
A second electrode on the second resistance layer;
One of the first electrode and the second electrode reflects light from the light emitting layer, and the other of the first electrode and the second electrode transmits light from the light emitting layer,
The display device includes at least one light emitting element having a total thickness of 1 μm or more of the first resistance layer and the second resistance layer.

In addition, this disclosure
A first electrode;
An organic layer including a light emitting layer made of an organic light emitting material on the first electrode;
A first resistive layer on the organic layer;
A second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer on the first resistance layer;
A second electrode on the second resistance layer;
One of the first electrode and the second electrode reflects light from the light emitting layer, and the other of the first electrode and the second electrode transmits light from the light emitting layer,
An illumination device having at least one light emitting element having a total thickness of 1 μm or more of the first resistance layer and the second resistance layer.

In the present disclosure, preferably, the electrical resistivity of the material constituting the first resistance layer is 1 × 10 ⁶ Ω · m or more and 1 × 10 ¹⁰ Ω · m, and the thickness of the first resistance layer is 0.1 μm. Although it is above 1 micrometer, it is not limited to this. Preferably, the electrical resistivity of the material constituting the second resistance layer is 1 × 10 ⁰ Ω · m or more and 1 × 10 ⁵ Ω · m, and the thickness of the second resistance layer is 0.5 μm or more. Although there is, it is not limited to this. Although the material which comprises a 1st resistance layer and a 2nd resistance layer is chosen as needed, it typically consists of an oxide semiconductor. As the oxide semiconductor, one kind or two or more kinds of conventionally known ones can be used.

  This light emitting element may be configured as a top emission type or a bottom emission type. In the top emission type light emitting element, the first electrode formed on the substrate reflects light from the light emitting layer, and the first resistance layer, the second resistance layer, and the second electrode transmit light from the light emitting layer. This substrate may be opaque or transparent and is selected as required. In the bottom emission type light emitting element, the first electrode, the first resistance layer, the second resistance layer, and the substrate formed on the substrate transmit light from the light emitting layer, and the second electrode transmits light from the light emitting layer. To reflect.

  The display device and the illumination device of the present disclosure can have a conventionally known configuration, and are appropriately configured according to their use and function. In a typical example, a display device is provided with a drive substrate provided with an active element (such as a thin film transistor) for supplying a display signal corresponding to each display pixel to a light emitting element, and facing the drive substrate. And a sealed substrate. The light emitting element is disposed between the driving substrate and the sealing substrate. This display device may be any one of a white display device, a monochrome display device, a color display device, and the like. In a color display device, typically, a color filter that transmits light emitted from the electrode side is provided on a substrate on the electrode side on which light of a light emitting element is emitted from the driving substrate and the sealing substrate. It is done.

  In the present disclosure described above, the first resistance layer and the second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer are formed on the organic layer, and these first resistances are formed. The total thickness of the layer and the second resistance layer is made sufficiently large to be 1 μm or more. For this reason, even if particles (foreign matter) and projections exist on the first electrode and the coverage of the organic layer formed thereon deteriorates, the particles (foreign matter) are caused by the first resistance layer and the second resistance layer. ) And protrusions are sufficiently covered. For this reason, it is possible to prevent a short circuit from occurring between the first electrode and the second electrode. Further, the thickness of the first resistance layer is not so large, and the first resistance layer is made thicker by increasing the thickness of the second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer. The total resistance of the resistance layer and the second resistance layer can be kept low. For this reason, the drive voltage of a light emitting element can be restrained low. In addition, since the distance between the first electrode and the second electrode can be made sufficiently large, the influence of light interference from the light emitting layer can be neglected. It can be made sufficiently small, and good viewing angle characteristics can be obtained.

  According to the present disclosure, even if particles (foreign matter) or protrusions exist on the first electrode, a short circuit does not occur between the first electrode and the second electrode, the viewing angle characteristics are good, and the drive voltage Low light emitting element can be realized. By using this excellent light-emitting element, a high-quality display device with favorable viewing angle characteristics and an illumination device with excellent light distribution characteristics with little angle dependency can be realized.

1 is a cross-sectional view showing an organic EL element according to Embodiment 1. FIG. FIG. 3 is a cross-sectional view illustrating a configuration example of an organic layer in the organic EL element according to Embodiment 1. FIG. 5 is a cross-sectional view for explaining the reason why a short circuit between the first electrode and the second electrode does not occur even when foreign matter is present on the first electrode in the organic EL element according to Embodiment 1. 5 is a schematic diagram showing a transmission spectrum when the thickness of the first resistance layer is fixed to 500 nm and the thickness of the second resistance layer is changed in the organic EL element according to Embodiment 1. FIG. FIG. 6 is a schematic diagram illustrating chromaticity viewing angle characteristics when the thickness of the first resistance layer is fixed to 500 nm and the thickness of the second resistance layer is changed in the organic EL element according to Embodiment 1. Chromaticity viewing angle when the total thickness of the first resistance layer and the second resistance layer changes by ± 10% when the thickness of the second resistance layer is fixed to 0 nm in the organic EL element according to the first embodiment It is a basic diagram which shows a characteristic. Chromaticity viewing angle when the total thickness of the first resistance layer and the second resistance layer changes by ± 10% when the thickness of the second resistance layer is fixed at 1000 nm in the organic EL element according to the first embodiment It is a basic diagram which shows a characteristic. FIG. 3 is a schematic diagram showing voltage-current density characteristics of two types of organic EL elements having different configurations of the first resistance layer and the second resistance layer in the first embodiment. 7 is a cross-sectional view showing a display device according to Embodiment 3. FIG. It is sectional drawing which shows the example which made the display apparatus by Embodiment 3 the module shape of the sealed structure. It is a perspective view which shows the television to which the display apparatus by Embodiment 3 is applied. It is a perspective view which shows the digital camera to which the display apparatus by Embodiment 3 is applied. FIG. 10 is a perspective view showing a notebook personal computer to which a display device according to Embodiment 3 is applied. It is a perspective view which shows the video camera to which the display apparatus by Embodiment 3 is applied. FIG. 10 is a perspective view showing a mobile phone to which a display device according to Embodiment 3 is applied. FIG. 6 is a perspective view showing a digital single-lens reflex camera to which a display device according to Embodiment 3 is applied. It is a perspective view which shows the head mounted display to which the display apparatus by Embodiment 3 is applied. It is sectional drawing which shows the organic electroluminescent illuminating device by Embodiment 4. It is sectional drawing for demonstrating the problem which the short circuit between a 1st electrode and a 2nd electrode arises by the foreign material which exists on a 1st electrode in the conventional organic EL element.

Hereinafter, modes for carrying out the invention (hereinafter referred to as “embodiments”) will be described. The description will be given in the following order.
1. Embodiment 1 (Organic EL device and manufacturing method thereof)
2. Embodiment 2 (Organic EL device and manufacturing method thereof)
3. Embodiment 3 (display device)
4). Embodiment 4 (lighting device)

<1. Embodiment 1>
[Organic EL device]
FIG. 1 shows an organic EL element according to the first embodiment. This organic EL element is a top emission type.

  As shown in FIG. 1, in this organic EL element, on the substrate 11, in order from the lower layer, the first electrode 12, the organic layer 13 including the light emitting layer 13a made of an organic light emitting material, the first resistance layer 14, the second The resistance layer 15 and the second electrode 16 are sequentially stacked.

  The substrate 11 may or may not be transparent to the light from the light emitting layer 13c, and may or may not be flexible, and can be made of various materials, and is selected as necessary. It is. Specifically, the substrate 11 is, for example, a transparent or opaque glass substrate or a semiconductor substrate such as a silicon substrate, but is not limited thereto.

  The first electrode 12 is used as an anode electrode also serving as a reflective layer. For example, light reflection of aluminum (Al), aluminum alloy, platinum (Pt), gold (Au), chromium (Cr), tungsten (W), etc. Consists of materials. The thickness of the first electrode 12 is preferably set in the range of 100 to 300 nm, but is not limited thereto. The first electrode 12 may be a transparent electrode as necessary. In this case, for example, Pt, Au, Cr, W, etc. are used for the purpose of forming a reflective interface between the first electrode 12 and the substrate 11. It is preferable to provide a reflective layer made of a light reflective material.

  The organic layer 13 includes a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a connection layer, and the like in addition to the light emitting layer 13a as necessary. In FIG. 2, as an example, the organic layer 13 is formed by sequentially laminating a hole injection layer 13b, a hole transport layer 13c, a light emitting layer 13a, an electron transport layer 13d, an electron injection layer 13e, and a connection layer 13f in order from the lower layer. A case having a structure is shown.

  The light emitting material of the light emitting layer 13a is appropriately selected according to the emission color. As the green light emitting material, for example, Alq3 (triskinolinol aluminum complex) can be used. As the red light-emitting material, for example, a material obtained by doping rubrene as a host material with a pyromethene boron complex can be used. As a blue light-emitting material, for example, a material obtained by doping ADN (9,10-di (2-naphthyl) anthracene) with a diaminochrysene derivative as a dopant material at a relative film thickness ratio of 5% can be used. The emission color of the light emitting layer 13a is not limited to a single color. For example, white light is emitted by stacking a plurality of light emitting layers having different light emission colors or by co-depositing a plurality of light emitting materials having different light emission colors. Or you may. The hole injection layer 13b is made of, for example, hexaazatriphenylene (HAT). The hole transport layer 13c is composed of, for example, α-NPD [N, N′-di (1-naphthyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine]. The The electron transport layer 13d is made of, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline). The electron injection layer 13e is made of, for example, lithium fluoride (LiF). The connection layer 13f is made of, for example, Alq3 or HAT doped with 5% of Mg. The thicknesses of these layers constituting the organic layer 13 are, for example, 5 to 50 nm for the light emitting layer 13a, 1 to 20 nm for the hole injection layer 13b, 15 nm to 100 nm for the hole transport layer 13c, and an electron transport layer. 13d and the electron injection layer 13e are preferably set in the range of 15 nm to 200 nm.

The first resistance layer 14 is configured to be transparent to the light from the light emitting layer 13a. The electrical resistivity of the material constituting the first resistance layer 14 is, for example, 1 × 10 ⁶ Ω · m to 1 × 10 ¹⁰ Ω · m (or 1 × 10 ⁴ Ω · cm to 1 × 10 ⁸ Ω · cm). Or less), preferably 1 × 10 ⁸ Ω · m or more and 1 × 10 ⁹ Ω · m or less (or 1 × 10 ⁶ Ω · cm or more and 1 × 10 ⁷ Ω · cm or less). Is not to be done. The thickness of the first resistance layer 14 is selected from 0.1 μm to 1 μm, for example, but is not limited thereto. Although the material which comprises the 1st resistance layer 14 is selected suitably, an oxide semiconductor is used suitably. Specific examples of the oxide semiconductor include niobium oxide (Nb ₂ O ₅ ), titanium oxide (TiO ₂ ), molybdenum oxide (MoO ₂ , MoO ₃ ), tantalum oxide (Ta ₂ O ₅ ), and oxide. Hafnium (HfO), IGZO, a mixture of niobium oxide and titanium oxide, a mixture of titanium oxide and zinc oxide (ZnO), a mixture of silicon oxide (SiO ₂ ) and tin oxide (SnO ₂ ), two of these materials The material which combined the above suitably can be mentioned. The electrical resistivity of the material constituting the first resistance layer 14 and the thickness of the first resistance layer 14 are appropriately determined from the driving voltage of the organic EL element and the coverage of the first resistance layer 14. Specifically, for example, when the organic EL element is driven, the first resistance layer 14 is set so that the voltage drop value in the first resistance layer 14 is 0.05 V or more and 1.0 V or less. The electrical resistivity of the constituent material and the thickness of the first resistance layer 14 are selected. As shown in FIG. 3, the thickness of the first resistance layer 14 is preferably set so that, for example, when the foreign material 17 exists on the first electrode 12, the first resistive layer 14 formed on the first resistive layer 14 has the foreign material. The second electrode 16 that completely covers 17 and is finally formed is selected so as not to contact the first electrode 12.

The second resistance layer 15 is configured to be transparent to the light from the light emitting layer 13a. The electric resistivity of the material constituting the second resistance layer 15 is, for example, 1 × 10 ⁰ Ω · m to 1 × 10 ⁵ Ω · m (or 1 × 10 ⁻² Ω · cm to 1 × 10 ³ Ω · m). cm or less), but is not limited thereto. The thickness of the second resistance layer 15 is, for example, 0.5 μm or more, preferably 1 μm or more, but is not limited thereto. There is no particular upper limit on the thickness of the second resistance layer 15, but the thickness of the second resistance layer 15 is generally 5 μm or less, typically 2 μm or less. Although the material which comprises the 2nd resistance layer 15 is chosen suitably, an oxide semiconductor is used suitably like the material which comprises the 1st resistance layer 14. Specific examples of the oxide semiconductor include niobium oxide (Nb ₂ O ₅ ), titanium oxide (TiO ₂ ), molybdenum oxide (MoO ₂ , MoO ₃ ), tantalum oxide (Ta ₂ O ₅ ), and oxide. Hafnium (HfO), IGZO, a mixture of niobium oxide and titanium oxide, a mixture of titanium oxide and zinc oxide (ZnO), a mixture of silicon oxide (SiO ₂ ) and tin oxide (SnO ₂ ), two of these materials The material which combined the above suitably can be mentioned. The material constituting the second resistance layer 15 may be the same as or different from the material constituting the first resistance layer 14, and is selected as necessary. By making the electrical resistivity of the material constituting the second resistance layer 15 lower than the electrical resistivity of the material constituting the first resistance layer 14, the second resistance layer can be obtained without increasing the drive voltage of the organic EL element. The thickness of 15 can be increased. When the material constituting the second resistance layer 15 is the same as the material constituting the first resistance layer 14, the electrical resistivity of the material constituting the second resistance layer 15 is set to the electric resistance of the material constituting the first resistance layer 14. In order to lower the resistivity, for example, the following is performed. That is, when the first resistance layer 14 and the second resistance layer 15 are formed by sputtering, for example, the electrical resistivity of both can be changed by adjusting the oxygen partial pressure in the atmosphere used for film formation. it can. Specifically, the oxygen partial pressure in the atmosphere when the second resistance layer 15 is formed is set lower than the oxygen partial pressure in the atmosphere when the first resistance layer 14 is formed, so that the second The electrical resistivity of the material constituting the resistance layer 15 can be made lower than the electrical resistivity of the material constituting the first resistance layer 14. By increasing the thickness of the second resistance layer 15, the distance between the first electrode 12 and the second electrode 16 can be increased, thereby reducing the pitch of light interference from the light emitting layer 12a, The influence of interference can be reduced.

  The second electrode 16 is transparent to the light from the light emitting layer 13a and is used as a cathode electrode. Specifically, the second electrode 16 is made of, for example, indium tin oxide (ITO) or an oxide of indium and zinc, which is generally used as a transparent electrode material. In general, since a transparent electrode tends to have light absorption in a wavelength region of 450 nm or less, when the transparent electrode is formed thick, light emitted from the light emitting layer 13a is absorbed particularly in blue light emission, and as a result, the light emission efficiency is improved. Since it falls, it is as thin as possible, specifically 200 nm or less, for example.

[Method of manufacturing organic EL element]
This organic EL element can be manufactured as follows, for example.
First, the substrate 11 is prepared.

  Next, a film made of the above electrode material is formed on the substrate 11 by, for example, a sputtering method, a vacuum deposition method, or the like, and the first electrode 12 is formed.

  Next, the organic layer 13 is formed on the first electrode 12 by a vacuum vapor deposition method or a coating method.

  Next, a film made of the above resistance material is formed on the organic layer 13 by, for example, sputtering, vacuum deposition, chemical vapor deposition (CVD), ion plating, or the like, and the first resistance layer 14 is formed. Form.

  Next, a film made of the above-described resistance material is formed on the first resistance layer 14 by, for example, a sputtering method, a vacuum evaporation method, a CVD method, an ion plating method, or the like, and the second resistance layer 15 is formed. At this time, the total thickness of the second resistance layer 15 and the first resistance layer 14 is set to 1 μm or more. As a result, as shown in FIG. 3, even when foreign matter 17 is present on the first electrode 12, foreign matter is caused by the thick second resistive layer 15 and first resistive layer 14 having a total thickness of 1 μm or more. Since 17 is completely covered, it is possible to prevent the second electrode 16 formed on the second resistance layer 15 from contacting the first electrode 12.

  Next, a film made of the above electrode material is formed on the second resistance layer 15 by, for example, a sputtering method or a vacuum deposition method, and the second electrode 16 is formed.

  Thereafter, the first electrode 12, the organic layer 13, the first resistance layer 14, the second resistance layer 15 and the second electrode 16 are patterned into a predetermined shape by etching or the like, if necessary.

  Thus, the target organic EL element shown in FIG. 1 is manufactured.

  FIG. 4 shows the change in the transmission spectrum for the light from the light emitting layer 13a when the thickness of the second resistance layer 15 is changed, and FIG. 5 shows the change in the chromaticity viewing angle characteristic. However, here, the emission color of the light emitting layer 13a is green, the thickness of the organic layer 13 is 200 nm, the thickness of the first resistance layer 14 is 500 nm, and the thickness of the second resistance layer 15 is 3 nm, 0 nm, 500 nm, and 1000 nm. A transparent electrode having a thickness of 200 nm was used as the second electrode 16. 4 that the interference pitch is narrowed by increasing the thickness of the second resistance layer 15, and accordingly, the chromaticity viewing angle characteristics are improved as shown in FIG. Further, by reducing the thickness of the second resistance layer 15 to reduce the influence of interference, it is possible to obtain an effect of reducing the change in viewing angle with respect to the thickness distribution of the second resistance layer 15.

  Chromaticity viewing angle characteristics when the total thickness of the first resistance layer 14 and the second resistance layer 15 when the thickness of the second resistance layer 15 is 0 nm changes by ± 10% with respect to the thickness of the center. FIG. 6 shows the change in the above. Further, when the thickness of the second resistance layer 15 is 1000 nm, the chromaticity field when the total thickness of the first resistance layer 14 and the second resistance layer 15 changes by ± 10% with respect to the thickness of the center. The change of the angular characteristic is shown in FIG. 6 and 7 that a good viewing angle characteristic is obtained even when the total thickness of the first resistance layer 14 and the second resistance layer 15 changes by ± 10%.

Even if the total thickness of the first resistance layer 14 and the second resistance layer 15 is increased in order to improve the viewing angle characteristics, the electrical resistivity of the material constituting the second resistance layer 15 will be higher than that of the first resistance layer 14. Since it is lower than the electrical resistivity of the constituent material, an increase in driving voltage of the light emitting element can be suppressed. This will be described as follows. That is, the electrical resistivity of the material constituting the first resistive layer 14 is 1 × 10 ⁶ Ω · cm, the thickness of the first resistive layer 14 is 500 nm, and the electrical resistivity of the material constituting the second resistive layer 15 is An organic EL element (element 1) was manufactured with 1 × 10 ³ Ω · cm and the second resistance layer 15 having a thickness of 1000 nm. The electric resistance of the material constituting the first resistance layer 14 is 1 × 10 ⁶ Ω · cm, and the thickness of the first resistance layer 14 is the sum of the first resistance layer 14 and the second resistance layer 15 of the element 1. An organic EL element (element 2) having a thickness equal to 1500 nm and having no second resistance layer 15 was produced. Thus, the element 1 in which the total thickness of the first resistance layer 14 and the second resistance layer 15 is 1500 nm is the same as the element 2 in which the thickness of the first resistance layer 14 is 1500 nm and the second resistance layer 15 is not provided. In comparison, the series resistance is reduced. The results of measuring the voltage-current density characteristics of these elements 1 and 2 are shown in FIG. As shown in FIG. 8, it can be seen that the voltage rise of the element 1 is suppressed as much as the series resistance is reduced compared to the element 2.

  As described above, according to the first embodiment, it is possible to prevent a short circuit between the first electrode 12 and the second electrode 16 even if the foreign matter 17 or the like is present on the first electrode 12. An excellent organic EL element having good viewing angle characteristics and low driving voltage can be realized. In addition, even if the total thickness of the first resistance layer 14 and the second resistance layer 15 changes, the change in viewing angle characteristics can be suppressed, so that the total of the first resistance layer 14 and the second resistance layer 15 is reduced. The margin for thickness increases. For this reason, the yield and quality of an organic EL element can be improved.

<2. Second Embodiment>
[Organic EL device]
This organic EL element is a bottom emission type. In this organic EL element, the substrate 11 and the first electrode 12 of the organic EL element according to Embodiment 1 are transparent to the light from the light emitting layer 13a, and the second electrode 16 reflects the light from the light emitting layer 13a. To do. Except for the above, the organic EL element is the same as the organic EL element according to the first embodiment.

[Method of manufacturing organic EL element]
The manufacturing method of the organic EL element is the same as the manufacturing method of the organic EL element according to the first embodiment.

  According to the second embodiment, the same advantages as those of the first embodiment can be obtained.

<3. Embodiment 3>
[Display device]
The display device according to the third embodiment is an active matrix display device in which the organic EL elements according to the first embodiment are arranged on a substrate. FIG. 9 shows the overall configuration of the display device 21.

  As shown in FIG. 9, on the substrate 11 of the display device 21, a display area 11a and a peripheral area 11b are provided. In the display area 11a, a plurality of scanning lines 22 and a plurality of signal lines 23 are wired vertically and horizontally, and configured as a pixel array section in which one pixel a is provided corresponding to each intersection. . Each pixel a is provided with an organic EL element 24. In the peripheral region 11b, a scanning line driving circuit 25 that scans the scanning lines 22 and a signal line driving circuit 26 that supplies a video signal (that is, an input signal) corresponding to the luminance information to the signal lines 23 are arranged. ing.

  The pixel circuit provided in each pixel a includes, for example, an organic EL element 24, a drive transistor Tr1, a write transistor (sampling transistor) Tr2, and a storage capacitor Cs. Then, the video signal written from the signal line 23 through the write transistor Tr2 is held in the holding capacitor Cs by driving by the scanning line driving circuit 25, and a current corresponding to the held signal amount is supplied to the organic EL element 24. Then, the organic EL element 24 emits light with a luminance corresponding to the current value. The driving thin film transistor Tr2 and the storage capacitor Cs are connected to a common power supply line (Vcc) 27.

  Note that the configuration of the pixel circuit as described above is merely an example, and a capacitor element may be provided in the pixel circuit as necessary, or a plurality of transistors may be provided to configure the pixel circuit. Further, a necessary drive circuit is added to the peripheral region 11b according to the change of the pixel circuit.

  The display device 21 includes a module having a sealed configuration as shown in FIG. For example, a sealing portion 29 is provided so as to surround the display area 11a which is a pixel array portion, and the sealing portion 29 is used as an adhesive and is attached to a facing portion (sealing substrate 30) such as transparent glass. Applicable display module. The transparent sealing substrate 30 may be provided with a color filter, a protective film, a light shielding film, and the like. The substrate 11 as a display module in which the display area 11a is formed may be provided with a flexible printed circuit board 31 for inputting / outputting signals to / from the display area 11a (pixel array unit) from the outside.

  According to the organic EL element 24 and the display device 21 described above, an excellent chromaticity field is achieved while preventing a short circuit between the first electrode 12 and the second electrode 16 due to the presence of the foreign matter 17 or the like on the first electrode 12. Angular characteristics can be obtained.

  The organic EL element 24 is not limited to use in the active matrix type display device 21 using a TFT substrate, but can be applied as an organic EL element used in a passive type display device, and obtains the same effect. be able to. In the case of a passive display device, one of the first electrode 12 and the second electrode 16 is configured as a signal line, and the other is configured as a scanning line.

  In Embodiment 3, the case where the organic EL element 24 is a top emission type in which light emission is extracted from the side of the first electrode 16 provided on the side opposite to the substrate 11 has been described. The bottom emission organic EL element according to the second embodiment which is taken out from the 11th side may be used. In this case, in the stacked structure described with reference to FIG. 1, the first electrode 12 on the substrate 11 made of a transparent material is configured using a transparent electrode material having a large work function such as ITO. Thereby, emitted light is extracted from both the substrate 11 side and the opposite side of the substrate 11. Further, by configuring the second electrode 16 with a reflective material in such a configuration, emitted light is extracted only from the substrate 11 side. In this case, a sealing electrode such as AuGe, Au, or Pt may be attached to the uppermost layer of the second electrode 16.

  The display device described above includes, for example, various electronic devices shown in FIGS. 11 to 15, such as digital cameras, notebook personal computers, mobile terminal devices such as mobile phones, and video input to electronic devices such as video cameras. The present invention can be applied to display devices for electronic devices in various fields that display signals or video signals generated in electronic devices as images or videos. Further, since the organic EL element 24 can be driven at a low voltage and enhances the light extraction efficiency to the front, the electronic viewfinder in the digital single-lens reflex camera shown in FIG. 16 or the head mount shown in FIG. It is very effective and particularly suitable for applications where low voltage driving is required, such as displays, where viewing angles with respect to the display are limited. Hereinafter, some examples of electronic devices to which the display device is applied will be described.

  FIG. 11 is a perspective view showing a television to which the display device is applied. The television according to this application example includes a video display screen unit 41 including a front panel 42, a filter glass 43, and the like, and is manufactured by using this display device as the video display screen unit 41.

  12A and 12B are perspective views showing a digital camera to which the display device is applied. FIG. 12A is a perspective view seen from the front side, and FIG. 12B is a perspective view seen from the back side. This digital camera includes a light emitting unit 51 for flash, a display unit 52, a menu switch 53, a shutter button 54, and the like, and is manufactured by using this display device as the display unit 52.

  FIG. 13 is a perspective view showing a notebook personal computer to which the display device is applied. This notebook personal computer includes a keyboard 62 that is operated when characters and the like are input, a display unit 63 that displays an image, and the like. The display unit 63 is used as the display unit 63.

  FIG. 14 is a perspective view showing a video camera to which the display device is applied. This video camera includes a main body 71, a lens 72 for photographing a subject on a side facing forward, a start / stop switch 73 at the time of photographing, a display 74, and the like. By using this display device as the display 74, Produced.

  15A to 15G show a mobile terminal device to which the display device is applied, for example, a mobile phone. FIG. 15A is a front view in an opened state, FIG. 15B is a side view thereof, and FIG. 15C is a closed state. 15D is a left side view, FIG. 15E is a right side view, FIG. 15F is a top view, and FIG. 15G is a bottom view. The cellular phone includes an upper casing 81, a lower casing 82, a connecting portion (here, a hinge portion) 83, a display 84, a picture light 86, a camera 87, a sub display 89, and the like. It is manufactured by using this display device.

  FIG. 16 shows a digital single-lens reflex camera to which this display device is applied, FIG. 16A is a front view, and FIG. 16B is a rear view. This digital single-lens reflex camera includes a camera main body 91, a photographing lens unit 92, a grip 93, a monitor 94, an electronic viewfinder 95, and the like, and is manufactured by using this display device as the electronic viewfinder 95. .

  FIG. 17 is a perspective view showing a head mounted display to which the display device is applied. This head mounted display includes a display unit 101, an ear hook unit 102, and the like, and is manufactured by using this display device as the display unit 101.

<4. Embodiment 4>
[Lighting device]
FIG. 18 shows an illumination apparatus according to the fourth embodiment.
As shown in FIG. 18, in this lighting device, the white organic EL element 111 according to the first embodiment is mounted on a transparent substrate 110. In this case, the white organic EL element 111 is mounted on the substrate 110 with the second electrode 16 side down. For this reason, the light emitted from the second electrode 16 side passes through the substrate 110 and is extracted outside. A sealing substrate 112 is provided so as to face the substrate 110 with the white organic EL element 111 interposed therebetween, and the outer periphery of the sealing substrate 112 and the substrate 110 is sealed with a sealing material 113. . The planar shape of the illuminating device is selected as necessary, and is, for example, a square or a rectangle. In FIG. 18, only one white organic EL element 111 is shown, but a plurality of white organic EL elements 111 may be mounted on the substrate 110 in a desired arrangement as necessary. Details of the configuration of the lighting device other than the white organic EL element 111 and configurations other than those described above are the same as those of a conventionally known organic EL lighting device.

  According to the fourth embodiment, the use of the white organic EL element 111 according to the first embodiment realizes an illumination device that has low angle dependency, good light distribution characteristics, low power consumption, and low cost. be able to.

  Although the embodiments have been specifically described above, the present technology is not limited to the above-described embodiments, and various modifications can be made.

  For example, the numerical values, structures, configurations, shapes, materials, and the like given in the above-described embodiments are merely examples, and different numerical values, structures, configurations, shapes, materials, and the like may be used as necessary.

In addition, this technique can also take the following structures.
(1) a first electrode, an organic layer including a light emitting layer made of an organic light emitting material on the first electrode, a first resistance layer on the organic layer, and the first resistance layer on the first resistance layer. A second resistance layer made of a material having a lower electrical resistivity than the material constituting the resistance layer; and a second electrode on the second resistance layer, wherein the first electrode and the second electrode One of the first and second electrodes reflects the light from the light emitting layer, and the other of the first electrode and the second electrode transmits the light from the light emitting layer. A light emitting device having a total thickness of 1 μm or more.
(2) The electric resistivity of the material constituting the first resistance layer is 1 × 10 ⁶ Ω · m to 1 × 10 ¹⁰ Ω · m, and the thickness of the first resistance layer is 0.1 μm to 1 μm. The light emitting device according to (1), wherein
(3) The electric resistivity of the material constituting the second resistance layer is 1 × 10 ⁰ Ω · m or more and 1 × 10 ⁵ Ω · m, and the thickness of the second resistance layer is 0.5 μm or more. The light emitting device according to (1) or (2).
(4) The light emitting element according to any one of (1) to (3), wherein the first resistance layer and the second resistance layer are made of an oxide semiconductor.
(5) The light emitting element according to any one of (1) to (4), wherein the first electrode is provided on a substrate.
(6) The first electrode reflects light from the light emitting layer, and the first resistance layer, the second resistance layer, and the second electrode transmit light from the light emitting layer. Light emitting element.
(7) The first electrode, the first resistance layer, and the second resistance layer transmit light from the light emitting layer, and the second electrode reflects light from the light emitting layer. Light emitting element.

  DESCRIPTION OF SYMBOLS 11 ... Board | substrate, 12 ... 1st electrode, 13 ... Organic layer, 13a ... Light emitting layer, 13b ... Hole injection layer, 13c ... Hole transport layer, 13d ... Electron transport layer, 13e ... Electron injection layer, 13f ... Connection layer , 14 ... 1st resistance layer, 15 ... 2nd resistance layer, 16 ... 2nd electrode, 24 ... Organic EL element, 110 ... Substrate, 111 ... White organic EL element, 112 ... Sealing substrate, 113 ... Sealing material

Claims (12)

A first electrode;
An organic layer including a light emitting layer made of an organic light emitting material on the first electrode;
A first resistive layer on the organic layer;
A second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer on the first resistance layer;
A second electrode on the second resistance layer;
One of the first electrode and the second electrode reflects light from the light emitting layer, and the other of the first electrode and the second electrode transmits light from the light emitting layer,
The light emitting element whose total thickness of the said 1st resistance layer and the said 2nd resistance layer is 1 micrometer or more. The material constituting the first resistance layer has an electrical resistivity of 1 × 10 ⁶ Ω · m to 1 × 10 ¹⁰ Ω · m, and the thickness of the first resistance layer is 0.1 μm to 1 μm. Item 2. A light emitting device according to Item 1. 3. The electrical resistivity of the material constituting the second resistance layer is 1 × 10 ⁰ Ω · m or more and 1 × 10 ⁵ Ω · m, and the thickness of the second resistance layer is 0.5 μm or more. The light emitting element of description.   The light emitting device according to claim 3, wherein the first resistance layer and the second resistance layer are made of an oxide semiconductor.   The light emitting device according to claim 4, wherein the first electrode is provided on a substrate.   The light emitting device according to claim 5, wherein the first electrode reflects light from the light emitting layer, and the first resistance layer, the second resistance layer, and the second electrode transmit light from the light emitting layer.   The light emitting device according to claim 5, wherein the first electrode, the first resistance layer, and the second resistance layer transmit light from the light emitting layer, and the second electrode reflects light from the light emitting layer. Forming a first electrode on a substrate;
Forming an organic layer including a light emitting layer made of an organic light emitting material on the first electrode;
Sequentially forming a first resistance layer and a second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer on the organic layer;
Forming a second electrode on the second resistance layer,
One of the first electrode and the second electrode reflects light from the light emitting layer, and the other of the first electrode and the second electrode transmits light from the light emitting layer,
A method for manufacturing a light emitting device, wherein the total thickness of the first resistance layer and the second resistance layer is 1 μm or more. A first electrode;
An organic layer including a light emitting layer made of an organic light emitting material on the first electrode;
A first resistive layer on the organic layer;
A second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer on the first resistance layer;
A second electrode on the second resistance layer;
One of the first electrode and the second electrode reflects light from the light emitting layer, and the other of the first electrode and the second electrode transmits light from the light emitting layer,
A display device comprising at least one light emitting element having a total thickness of 1 μm or more of the first resistance layer and the second resistance layer.   A driving substrate provided with an active element for supplying a display signal corresponding to each display pixel to the light emitting element; and a sealing substrate provided opposite to the driving substrate, wherein the light emitting element is The display device according to claim 9, wherein the display device is disposed between the driving substrate and the sealing substrate.   The display device according to claim 10, wherein a color filter that transmits light emitted from the second electrode side is provided on a substrate on the second electrode side of the light emitting element among the driving substrate and the sealing substrate. . A first electrode;
An organic layer including a light emitting layer made of an organic light emitting material on the first electrode;
A first resistive layer on the organic layer;
A second resistance layer made of a material having a lower electrical resistivity than the material constituting the first resistance layer on the first resistance layer;
A second electrode on the second resistance layer;
One of the first electrode and the second electrode reflects light from the light emitting layer, and the other of the first electrode and the second electrode transmits light from the light emitting layer,
A lighting device having at least one light emitting element having a total thickness of 1 μm or more of the first resistance layer and the second resistance layer.

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