JP5690578B2 - Organic electroluminescent device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an organic electroluminescent device and a method for manufacturing the same.

  Organic electroluminescent devices are expected as next-generation displays, lighting devices, backlights, and the like because they can emit surface light. In order to display a light emission pattern of characters or images on a display using the organic electroluminescence device, (1) a method of forming a luminance change pattern in the form of a display pattern in the surface of the organic electroluminescence device, and (2) an electrode And (3) a method in which electrodes are processed in a matrix and light-emitting display is performed using a drive circuit. These methods are selectively used according to the purpose of use of the organic electroluminescence device, the manufacturing cost, etc. For example, although the method of (1) can display only a specific pattern, an advanced fine processing technique accompanying patterning, In addition, complicated wirings and driving circuits are unnecessary, and a luminescent advertisement, a fixed display device, and the like can be manufactured at low cost.

As a method of forming the luminance change pattern, a driving voltage (hereinafter referred to as “a light exposure”) is partially applied by irradiating the light emitting surface of the organic electroluminescence element with an electromagnetic wave (hereinafter also referred to as “exposure” to “light irradiation”). Several methods have been proposed for increasing the light emission luminance by increasing the light emission start voltage).
For example, a method for patterning an organic electroluminescent element has been proposed in which a light-emitting layer made of a light-emitting material is irradiated with ultraviolet light and the irradiated portion is a non-light-emitting region (see Patent Document 1).
Further, in a method for producing a laminated organic electroluminescent device having at least one hole transport layer containing an arylamine and an electron transporting light emitting layer, the characteristics of the hole transport layer are changed by electromagnetic wave irradiation, and the organic electroluminescent device It has been proposed to adjust the brightness of the light emitting part partially and arbitrarily (see Patent Document 2).

In these proposals, the drive voltage of the irradiated portion increases due to the electromagnetic wave irradiation, and current flows nonuniformly in the light emitting surface, thereby making it possible to produce a contrast in the light emitting surface with a difference in light emission luminance.
However, the driving voltage and luminance of the organic electroluminescence device are not proportional, and the electromagnetic wave irradiation time and the amount of increase in driving voltage are not a simple proportional relationship. Must be corrected from the voltage-current density characteristics of the organic electroluminescent element and the electromagnetic wave irradiation amount-voltage increase amount, and the work is complicated. In addition, when the gradation of the image is expressed by changing the intensity of the electromagnetic wave to be radiated as in these proposals, the image may be blurred due to the deviation of the light and shade of the exposure mask. There has been a problem that the image of the organic electroluminescent element cannot be accurately expressed depending on the light emission luminance.

  Therefore, there is a need for an organic electroluminescence device that can be used to control gradation in electromagnetic wave irradiation and that can accurately express gradation with good reproducibility regardless of the luminance of the device, and a method for manufacturing the same. Is the current situation.

Japanese Patent No. 2793373 Japanese Patent No. 3599077

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention provides an organic electroluminescent device in which a desired luminance change pattern is formed more easily, with a clear image quality, and with good reproducibility without being affected by the voltage-current characteristics of the device, and a method for manufacturing the same. The purpose is to provide.

Means for solving the above problems are as follows. That is,
<1> A light emitting layer is provided between the anode and the cathode,
An organic electroluminescent element having an area gradation composed of a luminance change pattern in which luminance is changed at least in a part of a light emitting surface.
<2> The organic electroluminescence device according to <1>, wherein the luminance change pattern is formed by electromagnetic wave irradiation.
<3> The organic electroluminescence device according to <2>, wherein the electromagnetic wave irradiation is performed through an exposure mask having a pattern in which a change in electromagnetic wave transmittance is displayed in binary.
<4> The organic electroluminescence device according to <2>, wherein the electromagnetic wave irradiation is performed by scanning the surface of the organic electroluminescence device that is changed in binary.
<5> The organic electroluminescence device according to any one of <1> to <4>, wherein the resolution of the luminance change pattern is 100 dpi or more.
<6> The organic electroluminescence device according to any one of <2> to <5>, wherein a drive voltage in a portion irradiated with electromagnetic waves is increased and a current amount is decreased.
<7> The amount of current (A) that flows per area when a specific voltage is applied to a portion irradiated with electromagnetic waves, and the area when the same voltage as the voltage is applied to a portion that is not irradiated with electromagnetic waves The organic electroluminescence device according to any one of <2> to <6>, wherein a ratio (B / A) to a flowing current amount (B) is 3 or more.
<8> The organic electroluminescence device according to any one of <1> to <7>, wherein at least one of the anode and the cathode is a metal oxide electrode.
<9> The organic electroluminescent element according to any one of <1> to <8>, wherein the visible light transmittance is 20% or more.

<10> The organic electroluminescence device according to any one of <1> to <9>, which has flexibility.
<11> The organic electroluminescence device according to any one of <2> to <10>, further including an electromagnetic wave absorbing layer that absorbs an electromagnetic wave having a wavelength used in electromagnetic wave irradiation on a light emitting surface.
<12> The organic electroluminescence device according to any one of <1> to <10>, wherein the luminance unevenness in the light emitting surface is corrected by irradiating electromagnetic waves.
<13> An organic electroluminescent element production step of producing an organic electroluminescent element having a light emitting layer between an anode and a cathode;
A method of forming an organic electroluminescence device, comprising: a luminance change pattern forming step of irradiating an electromagnetic wave so that the luminance change pattern has an area gradation on at least a part of a light emitting surface of the organic electroluminescence device. is there.
<14> The method for producing an organic electroluminescent element according to <13>, wherein the electromagnetic wave irradiation is performed through an exposure mask having a pattern in which a change in electromagnetic wave transmittance is expressed in binary.
<15> The method for producing an organic electroluminescent element according to <13>, wherein the electromagnetic wave irradiation is performed by changing the binary value and scanning the organic electroluminescent upper element.
<16> The method for producing an organic electroluminescent element according to any one of <13> to <15>, further including a luminance unevenness correcting step of correcting the luminance unevenness in the light emitting surface by irradiating electromagnetic waves.
<17> In any one of the above items <13> to <15>, in the luminance change pattern forming step, the luminance unevenness correction in the light emitting surface of the organic electroluminescent element and the formation of the area gradation composed of the luminance change pattern are simultaneously performed. It is a manufacturing method of the organic electroluminescent element of description.

  According to the present invention, conventional problems can be solved, and the present invention makes it possible for the desired luminance change pattern to be more easily and with good image quality and good reproducibility without being affected by the voltage-current characteristics of the device. It is possible to provide a formed organic electroluminescent device and a method for manufacturing the same.

FIG. 1 is an example of a graph for explaining voltage-luminance characteristics before and after electromagnetic wave irradiation in an organic electroluminescent element. FIG. 2 is a graph showing the in-plane luminance distribution of the organic electroluminescent element before luminance unevenness correction in Example 5. FIG. 3 is a graph showing the in-plane luminance distribution of the organic electroluminescent element after correcting the luminance unevenness in Example 5. FIG. 4 is an image serving as a basis for pattern display on the organic electroluminescent elements of Examples 1 to 9 and Comparative Examples 1 to 7. FIG. 5 is an image obtained by binarizing the image of FIG. FIG. 6 is an exposure mask image for performing luminance unevenness correction and light emission pattern formation in Example 9 at the same time.

(Organic electroluminescence device)
The organic electroluminescent element of the present invention has a light emitting layer between an anode and a cathode, and has an area gradation composed of a luminance change pattern in which the luminance is changed at least partially in the light emitting surface.

<Luminance change pattern>
The luminance change pattern is a pattern formed by changing the luminance in at least a part of the light emitting surface of the organic electroluminescent element, and can display the pattern when the organic electroluminescent element emits light. is there.
The method for changing the luminance is not particularly limited and can be appropriately selected according to the purpose. However, electromagnetic radiation is preferable from the viewpoint that the operation is simple and the power efficiency is not lowered. A luminance change pattern can be formed by partially increasing the drive voltage and decreasing the luminance in the light emitting surface by the electromagnetic wave irradiation.

  In the present invention, it is essential that the gradation method of the luminance change pattern is an area gradation. Here, area gradation refers to creating a portion with strong light emission and a portion with low light emission, and expressing the gradation with the area ratio. By setting the luminance change pattern to area gradation, a pattern can be formed with good image quality and good reproducibility without being affected by the voltage-current characteristics of the element. Details thereof will be described later.

The electromagnetic wave has a vacuum wavelength in the range of about 10 ⁻¹⁷ m to 10 ⁵ m, and includes γ rays, X rays, ultraviolet rays, visible rays, infrared rays, and the like. Among these, ultraviolet rays or visible rays are preferable.
As a light source of the electromagnetic wave irradiation apparatus, for example, a high pressure mercury lamp, a low pressure mercury lamp, a hydrogen (deuterium) lamp, a rare gas (for example, xenon, argon, helium, neon) discharge lamp, a nitrogen laser, an excimer laser (for example, , XeCl, XeF, KrF, KrCl, etc.), hydrogen laser, halogen laser, harmonics of various visible-infrared lasers, and the like.
These may be used individually by 1 type and may use 2 or more types together.

  The electromagnetic wave irradiation device is not particularly limited as long as light can be emitted from the various light sources, and commercially available products can be used. Examples of the commercially available product include an amber tester (light source: xenon lamp, manufactured by Shinto Kagaku Co., Ltd.), a blue-violet semiconductor laser KLX-120 mW type (emission peak: 405 nm, manufactured by Kikko Giken Co., Ltd.), and the like.

The electromagnetic wave irradiation method is not particularly limited as long as the gradation method of the luminance change pattern is an area gradation, and can be appropriately selected according to the purpose. It is preferable to perform the method through an exposure mask having a pattern in which the change in transmittance is expressed in binary. Moreover, it is not necessary to prepare an exposure mask, and the method of scanning the organic electroluminescent element by changing the electromagnetic wave irradiation in a binary manner is preferable because it is inexpensive.
As the binarization method, for example, an error diffusion method, a dither matrix method, or the like can be used.

  The luminance change pattern of the area gradation and the resolution of the exposure mask are not particularly limited and can be appropriately selected according to the purpose, but are usually 50 dpi or more, preferably 100 dpi or more, and more preferably 200 dpi or more. . If the resolution is less than 50 dpi, the displayed image may feel granularity.

  As a method for producing the exposure mask, for example, a desired image is binarized by an error diffusion method using an image processing software (for example, Photoshop elements 3.0 manufactured by Adobe), and an image obtained by reversing black and white is obtained. The method of producing and printing on an OHP sheet with an inkjet printer is mentioned.

As a method of changing electromagnetic wave irradiation by binary values, for example, the presence or absence of irradiation may be changed, or either irradiation intensity or irradiation time may be changed by binary values.
Examples of the scanning method include a method in which a laser that irradiates an electromagnetic wave is installed on an automatically controlled xy stage (ALD-220-C2P, manufactured by Chuo Seiki Co., Ltd.), and the laser is moved in the xy direction. .

The irradiation dose of the electromagnetic wave is not particularly limited, as appropriate may be ^{selected, 1J / cm 2 ~10,000J / cm} 2 are preferred according to the ^{purpose, 5J / cm 2 ~1,000J / cm} 2 Is more preferable. When the irradiation amount is less than 1 J / cm ² , the voltage rise is insufficient, and there may be a case where brightness contrast is not achieved between the exposed portion and the unexposed portion, and when it exceeds 10,000 J / cm ^2. In addition to the increase in driving voltage, the entire device may deteriorate.

  In addition, since it is necessary to provide an image contrast in order to display the light emission pattern with high image quality, the amount of irradiation of the electromagnetic wave is a current flowing per area when a specific voltage is applied to a portion irradiated with the electromagnetic wave. The ratio (B / A) between the amount (current density) (A) and the current density (B) when a voltage equal to the above voltage is applied to a portion not irradiated with electromagnetic waves is set to be 3 or more. It is preferable to do. When the ratio (B / A) is less than 3, the brightness difference between the bright part and the dark part is small, and the contrast of the displayed image may deteriorate.

  The current density is obtained by cutting out a sample of a portion irradiated with electromagnetic waves and a sample of a portion not irradiated with electromagnetic waves from the light emitting surface of the organic electroluminescent element after the luminance change pattern is formed, and connecting the electrode portion of each sample and a power source. , And can be measured by applying the same voltage. The voltage to be applied at this time is preferably measured by a voltage that is driven when the element becomes a product displaying a specific pattern, and specifically, about 3 V to 10 V is preferable.

In addition, the organic electroluminescent element of this invention may correct | amend the brightness nonuniformity in a light emission surface before and after forming a brightness change pattern, or simultaneously with the formation of a brightness change pattern.
The method for correcting the luminance unevenness is not particularly limited, and a known method can be used. However, if the correction is not performed with light and shade gradations, the deterioration progresses unevenly during energization and uneven luminance in the reverse direction is generated. It is preferable that the luminance variation pattern is formed with the area gradation after correcting the luminance unevenness with the gradation gradation.

Hereinafter, the superiority of expressing the image pattern of the organic electroluminescent element by area gradation will be described.
Here, the element configuration of the organic electroluminescence element is, in order from the anode, ITO (100) /0.3 mass% F4TCNQ-doped 2-TNATA (5) / 2-TNATA (115) / NPD (4) / HTL. -1 (3) / mCP (3) / 40 wt% PT-1 doped mCP (30) / BAlq (39) / BCP (1) / LiF (1) / Al (100) A white organic electroluminescent element sealed with a stop glass will be described as an example. The values in parentheses represent the average thickness of the layer, and the unit is “nm”. In addition, among the components, F4TCNQ, 2-TNATA, NPD, HTL-1, mCP, PT-1, BAlq, and BCP are represented by the following structural formula.

FIG. 1 shows the relationship between drive voltage and luminance when the element is irradiated with electromagnetic waves of 250 mW / cm ² for 60 minutes from a xenon mercury lamp. As can be seen from FIG. 1, the drive voltage rises due to the electromagnetic wave irradiation. At this time, although not shown, the current-luminance characteristics are almost the same before and after the electromagnetic wave irradiation. Therefore, when the part irradiated with electromagnetic waves and the part not irradiated with electromagnetic waves are made in the light emitting surface, the current is difficult to flow in the part irradiated with electromagnetic waves due to the high voltage, and the current flows only to the part not irradiated with electromagnetic waves. Become. In the case of this element, when a voltage of 6 V is applied, light emission of about 1,000 cd / m ² is observed in the part not irradiated with electromagnetic waves, whereas light of only about 120 cd / m ² is emitted in the part irradiated with electromagnetic waves. The contrast ratio at this voltage is about 10: 1. However, when comparing the luminance with 10V applied, respectively 9,000cd / ^{m 2} and 3,300cd / ^{m 2} next to the contrast ratio of 3: varies about 1. That is, when adjusting the drive voltage increase by adjusting the driving voltage by applying a gradation to the electromagnetic wave irradiation amount, and adjusting the in-plane luminance, the ratio of the current value flowing by the applied voltage even with the same irradiation amount ratio, that is, It can be seen that the current density changes. In addition, since a change in luminance is large with respect to a voltage change, it is difficult to precisely control the amount of increase in voltage and exposure with a stable image quality if there is variation among elements and variation during electromagnetic wave irradiation. This is the same regardless of the element configuration.

  The present invention uses an exposure mask having a high-resolution pattern obtained by binarizing a desired image by an error diffusion method or a dither matrix method, or changes the electromagnetic wave irradiation by a binary value and scans the organic electroluminescent element. Then, it is proposed to express gradation by area gradation. As a result, the area ratio between the portion that emits light with high luminance and the portion that emits light is constant even when the voltage is changed, so that it is possible to always make the image constant regardless of the voltage applied. . In addition, since this method has low dependency on changes in the voltage-luminance characteristics of the element, exposure can be performed without being affected by variations in element performance and variations in the light source to irradiate, and a constant image quality can always be obtained. Can do.

In addition, when irradiating electromagnetic waves, the area gradation can be accurately adjusted by adjusting the electromagnetic wave irradiation amount so that the luminance difference when applying an equal voltage to the part irradiated with electromagnetic waves and the part not irradiated with electromagnetic waves becomes large. Can be expressed in This is because, if the area of a certain electromagnetic radiation portion when to be expressed at 50 cd / m ² brightness portion and unirradiated part 1: When 1, the electromagnetic wave non luminance of the irradiated area 100 cd / m ^2, electromagnetic radiation If the electromagnetic wave is irradiated so that the luminance of the portion becomes almost zero, it appears to have an average brightness of 50 cd / m ² , and even if the current density changes, the emission of the electromagnetic wave irradiated portion is very low, so the luminance is hardly affected. Therefore, brightness can be expressed only by area ratio. However, for example, when the electromagnetic wave is irradiated so that the area of the electromagnetic wave irradiated part and the electromagnetic wave non-irradiated part is 1: 1, the electromagnetic wave non-irradiated part is 60 cd / m ² , and the electromagnetic wave irradiated part is approximately 40 cd / m ^2. Similarly, the brightness appears to be 50 cd / m ^{2 on} average, but if the current ratio is changed and the luminance ratio between the electromagnetic wave irradiation part and the electromagnetic wave non-irradiation part changes, the brightness of the electromagnetic wave irradiation part cannot be ignored. Therefore, the brightness is not determined only by the area. Therefore, it is possible to set the irradiation amount of electromagnetic waves so that the luminance when an equal voltage is applied at least in an electromagnetic wave irradiated part and an electromagnetic wave non-irradiated part is different by 3 times or more in a region of 5,000 cd / m ² or less. It is important to establish a key.

Below, the element structure of the organic electroluminescent element in this invention is demonstrated.
The organic electroluminescent element has a pair of electrodes, that is, an anode and a cathode, and an organic layer including a light emitting layer between both electrodes, and further, if necessary, a hole injection layer, a hole transport layer, and an electron transport. Other components such as various functional layers such as a layer, a hole blocking layer, an electron blocking layer, and an electron injection layer, a substrate, and a protective layer may be included.
Each of these layers usually forms a laminated structure, and has a laminated structure in which the hole injection layer is provided on the anode. A hole transport layer is preferably provided between the stacked structure and the light emitting layer, and an electron transport layer is preferably provided between the cathode and the light emitting layer. An electron injection layer may be provided between the electron transport layer and the cathode. Further, a hole transporting intermediate layer (electron blocking layer) may be provided between the light emitting layer and the hole transporting layer, and an electron transporting intermediate layer (hole blocking layer) between the light emitting layer and the electron transporting layer. ) May be provided. Each of the layers may be divided into a plurality of secondary layers.

  The organic layer including the light emitting layer can be formed according to a known method, and is suitable for, for example, a dry film forming method such as a vapor deposition method or a sputtering method, a wet coating method, a transfer method, a printing method, an ink jet method, or the like. Can be formed.

There is no restriction | limiting in particular as a property of the said organic electroluminescent element, It can select suitably according to the objective, Transparent or opaque may be sufficient, and when transparent, it may be colorless and transparent or colored and transparent. Moreover, you may have flexibility. When the organic electroluminescent element is transparent or flexible, the range of uses can be expanded.
In addition, as a transmittance | permeability, it is at least 20% or more as visible light transmittance, 40% or more is preferable, and 60% or more is more preferable.

<< Electrode >>
The organic electroluminescent element includes a pair of electrodes, that is, an anode and a cathode. In view of the nature of the organic electroluminescence device, at least one of the anode and the cathode is preferably transparent. Usually, the anode only needs to have a function as an electrode for supplying holes to the organic compound layer, and the cathode only needs to have a function as an electrode for injecting electrons into the organic compound layer.
There is no restriction | limiting in particular about the shape, a structure, a magnitude | size, etc. as said electrode, According to the use and objective of an organic electroluminescent element, it can select suitably from well-known electrode materials.
Examples of the material constituting the electrode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof.

-Anode-
Examples of the material constituting the anode include tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Conductive metal oxides; metals such as gold, silver, chromium and nickel; mixtures or laminates of these metals and conductive metal oxides; inorganic conductive materials such as copper iodide and copper sulfide; polyaniline, polythiophene, Examples thereof include organic conductive materials such as polypyrrole, and laminates of these with ITO. Among these, a conductive metal oxide is preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like.

  The method for forming the anode is not particularly limited and can be performed according to a known method, for example, a wet method such as a printing method or a coating method; a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method. Chemical methods such as CVD and plasma CVD may be used. Of these, it can be formed on the substrate according to a method selected appropriately in consideration of suitability with the material constituting the anode. For example, when selecting ITO as the material of the anode, direct current or high frequency It can be formed by sputtering, vacuum deposition, ion plating, or the like. In addition, when selecting a metal etc. as a cathode material mentioned later, the 1 type (s) or 2 or more types can be formed by the sputtering method etc. simultaneously or sequentially.

-Cathode-
There is no restriction | limiting in particular as a material which comprises the said cathode, According to the objective, it can select suitably, For example, an alkali metal (for example, Li, Na, K, Cs etc.), an alkaline earth metal (for example, Mg, Ca) Etc.), gold, silver, lead, aluminum, sodium-potassium alloy, lithium-aluminum alloy, magnesium-silver alloy, rare earth metals such as indium and ytterbium. These may be used singly or in combination of two or more from the viewpoint of achieving both stability and electron injection.
Among these, alkali metals and alkaline earth metals are preferable from the viewpoint of electron injection properties, and materials mainly composed of aluminum are preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01% by mass to 10% by mass of alkali metal, or alkaline earth metal or a mixture thereof (for example, lithium-aluminum alloy, magnesium- An aluminum alloy).

  There is no restriction | limiting in particular about the formation method of the said cathode, According to a well-known method, it can carry out and the method similar to the formation method of the above-mentioned anode can be used.

  In addition, when patterning is performed when forming the anode and the cathode, the patterning may be performed by chemical etching using photolithography or the like, or by physical etching using a laser or the like. Further, the masks may be overlapped by vacuum steaming, sputtering, or the like, or by a lift-off method or a printing method.

The electrode may be subjected to a surface treatment using oxygen, nitrogen, a rare gas, or the like.
The surface treatment is not particularly limited and may be appropriately selected according to the purpose. For example, known surface treatment methods such as various kinds of sputtering such as plasma treatment and ion beam sputtering, ultraviolet irradiation treatment, and radical beam treatment may be used. Can be mentioned. Among these, plasma processing is preferable in that it can be processed in a short time and can be performed in various gas atmospheres.

  As the plasma treatment, the apparatus and conditions can be appropriately selected as long as the gas can be converted into plasma and the substrate surface can be treated. However, the plasma treatment is preferably performed under the condition that the plasma surface does not cause unevenness of the electrode surface. Under the condition that the unevenness of the electrode surface becomes larger than that before the treatment, there is a possibility that a short circuit between the electrodes is likely to occur when an organic electroluminescent element is formed.

<< Light emitting layer >>
The light emitting layer receives holes from an anode, a hole injection layer, or a hole transport layer when an electric field is applied, and receives electrons from any one of a cathode, an electron injection layer, and an electron transport layer. It is a layer having a function of providing a recombination field to emit light.
The light emitting layer includes a light emitting material. The light emitting layer may be composed only of a light emitting material, or may be a mixed layer of a host material and a light emitting material (in the latter case, the light emitting material may be referred to as a “light emitting dopant” or “dopant”).
Furthermore, the light emitting layer may contain a material that does not have charge transporting properties and does not emit light.

There is no restriction | limiting in particular as average thickness of the said light emitting layer, Although it can select suitably according to the objective, 2 nm-500 nm are preferable, 3 nm-200 nm are more preferable from a viewpoint of external quantum efficiency, and 5 nm-100 nm are preferable. Particularly preferred.
Moreover, the said light emitting layer may be 1 layer, or may be two or more layers, and each layer may light-emit with a different luminescent color.

-Luminescent material-
There is no restriction | limiting in particular as said luminescent material, According to the objective, it can select suitably, A fluorescent luminescent material may be sufficient and a phosphorescent luminescent material may be sufficient. Moreover, these may be used individually by 1 type and may use 2 or more types together.
The light emitting dopant has an ionization potential difference (ΔIp) and an electron affinity difference (ΔEa) of 1.2 eV>ΔIp> 0.2 eV and / or 1.2 eV>ΔEa> 0 with the host compound. A dopant satisfying the relationship of .2 eV is preferable from the viewpoint of driving durability.
The content of the luminescent dopant in the luminescent layer is preferably 0.1% by mass to 50% by mass with respect to the total mass of the compound generally forming the luminescent layer in the luminescent layer. 1 mass%-50 mass% are more preferable from a viewpoint of efficiency, and 2 mass%-40 mass% are especially preferable.

--Phosphorescent material--
There is no restriction | limiting in particular as said phosphorescence-emitting material, According to the objective, it can select suitably, The complex etc. which contain a transition metal atom or a lanthanoid atom are mentioned.
There is no restriction | limiting in particular as said transition metal atom, According to the objective, it can select suitably, For example, ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, gold | metal | money, silver, copper, platinum etc. are mentioned. Among these, rhenium, iridium, and platinum are preferable, and iridium and platinum are particularly preferable.

  Examples of the ligand of the complex include G.I. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H.C. Examples include ligands described in Yersin's "Photochemistry and Photophysics of Coordination Compounds" published by Springer-Verlag 1987, Akio Yamamoto "Organic Metal Chemistry-Fundamentals and Applications-" .

  The complex may have one transition metal atom in the compound or may be a so-called binuclear complex having two or more. Different metal atoms may be contained at the same time.

Examples of the phosphorescent material include, for example, US Pat. No. 6,303,238, US Pat. No. 6,097,147, WO00 / 57676, WO00 / 70655, WO01 / 08230, WO01 / 39234, WO01. / 41512 pamphlet, WO02 / 02714 pamphlet, WO02 / 15645 pamphlet, WO02 / 44189 pamphlet, WO05 / 19373 pamphlet, WO2004 / 108857 pamphlet, WO2005 / 042444 pamphlet, WO2005 / 042550 pamphlet, JP2001. JP-A No. 247859, JP-A No. 2002-302671, JP-A No. 2002-117978, and JP-A No. 2003. JP 133074, JP 2002-235076, JP 2003-123982, JP 2002-170684, EP 12111257, JP 2002-226495, JP 2002-234894, special JP-A-2001-247859, JP-A-2001-298470, JP-A-2002-173675, JP-A-2002-203678, JP-A-2002-203679, JP-A-2004-357791, JP-A-2006 Phosphorescence described in JP-A No. 93542, JP-A 2006-261623, JP-A 2006-256999, JP-A 2007-19462, JP-A 2007-84635, JP-A 2007-96259, and the like. Compound etc. are mentioned.
Among these, Ir complex, Pt complex, Cu complex, Re complex, W complex, Rh complex, Ru complex, Pd complex, Os complex, Eu complex, Tb complex, Gd complex, Dy complex, and Ce complex are preferable, and Ir complex Pt complex and Re complex are more preferable, Ir complex including at least one coordination mode of metal-carbon bond, metal-nitrogen bond, metal-oxygen bond and metal-sulfur bond, Pt complex, and Re complex are more preferable. From the viewpoints of luminous efficiency, driving durability, chromaticity, and the like, Ir complexes, Pt complexes, and Re complexes containing a tridentate or higher polydentate ligand are particularly preferable.

  Specific examples of the phosphorescent material that can be used in the present invention include, but are not limited to, the following compounds.

--Fluorescent material--
The fluorescent material is not particularly limited and can be appropriately selected according to the purpose. For example, benzoxazole, benzimidazole, benzothiazole, styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, Coumarin, pyran, perinone, oxadiazole, aldazine, pyralidine, cyclopentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, cyclopentadiene, styrylamine, aromatic dimethylidin compounds, condensed polycyclic aromatic compounds (for example, , Anthracene, phenanthroline, pyrene, perylene, rubrene, or pentacene), 8-quinolinol metal complexes; various metal complexes typified by pyromethene complexes and rare earth complexes; poly Thiophene, polyphenylene, polymeric compounds such as polyphenylene vinylene; organic silane, and derivatives thereof. These may be used individually by 1 type and may use 2 or more types together.

-Host material-
The host material is preferably a charge transport material. The host material may be one type or two or more types.
As the charge transporting material, a hole transporting host material having excellent hole transporting property and an electron transporting host material having excellent electron transporting property can be used.

--Hole-transporting host material--
The hole transporting host material is not particularly limited and may be appropriately selected depending on the purpose. For example, pyrrole, indole, carbazole, azaindole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole, Imidazole, thiophene, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic tertiary amine compound, styrylamine compound, aromatic dimethylidin compound , Porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole), aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, organosilanes Carbon film, or a derivative thereof, and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, indole derivatives, carbazole derivatives, aromatic tertiary amine compounds, and thiophene derivatives are preferable, those having a carbazole group in the molecule are more preferable, and compounds having a t-butyl-substituted carbazole group are particularly preferable.

--- Electron transporting host material--
The electron transporting host material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include pyridine, pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole, oxadiazol, and fluorenone. , Anthraquinodimethane, anthrone, diphenylquinone, thiopyran dioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, fluorine-substituted aromatic compounds, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene; phthalocyanines or their derivatives (It may form a condensed ring with other rings), metal complexes of 8-quinolinol derivatives, various metal complexes represented by metal complexes having metal phthalocyanine, benzoxazole and benzothiazol as ligands Etc. These may be used individually by 1 type and may use 2 or more types together.
Among these, from the viewpoint of durability, a metal complex compound is preferable, and a metal complex having a ligand having at least one nitrogen atom, oxygen atom, or sulfur atom coordinated to a metal is more preferable.
Examples of the metal complex compound include Japanese Patent Application Laid-Open No. 2002-235076, Japanese Patent Application Laid-Open No. 2004-214179, Japanese Patent Application Laid-Open No. 2004-221106, Japanese Patent Application Laid-Open No. 2004-221106, Japanese Patent Application Laid-Open No. 2004-221068, and the like. Examples thereof include compounds described in JP-A No. 2004-327313.

  Examples of the hole transporting host material and the electron transporting host material that can be used in the present invention include the following compounds and deuterated compounds thereof, but are not limited thereto.

<Other ingredients>
The organic electroluminescent device of the present invention includes, as other components, a hole injection layer, a hole transport layer, a hole transport intermediate layer (electron block layer), an electron transport intermediate layer (hole block layer), and an electron transport. Each functional layer of the layer and the electron injection layer, a substrate, a protective layer, and the like may further be included.

<< Hole Injection Layer >>
The hole injection layer is a layer having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. The hole injection layer may have a single layer structure or a multilayer structure composed of a plurality of layers having the same composition or different compositions.
The hole injection material may be a low molecular compound or a high molecular compound, and can be appropriately selected according to the purpose. For example, a pyrrole derivative, a carbazole derivative, a triazole derivative, or an oxazole derivative. , Oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic Group tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, phthalocyanine compounds, porphyrin compounds, thiophene derivatives, organosilane derivatives, carbon, etc. . Among these, arylamine derivatives are preferred in that the drive voltage is likely to increase due to electromagnetic wave exposure in an organic electroluminescent device using a material having an arylamine skeleton for the hole injection layer.
These may be used individually by 1 type and may use 2 or more types together.

  The method for forming the hole injection layer is not particularly limited, and a known method can be used.For example, a vapor deposition method, a dry film forming method such as a sputtering method, a wet coating method, a transfer method, a printing method, It can be suitably formed by an inkjet method or the like.

Specific examples of the hole injection material that can be used in the present invention include, but are not limited to, the following compounds.

The hole injection layer may be p-doped, and specifically contains an electron accepting compound.
The p-doped hole injection layer can be formed by co-evaporation of a hole injection material and an electron accepting compound.

The electron-accepting compound may be an inorganic compound or an organic compound as long as it has an electron-accepting property and oxidizes an organic compound.
Examples of the inorganic compound include metal halides such as ferric chloride, aluminum chloride, gallium chloride, indium chloride, and antimony pentachloride; metal oxides such as vanadium pentoxide and molybdenum trioxide.
Examples of the organic compound include compounds having a nitro group, a halogen, a cyano group, a trifluoromethyl group or the like as a substituent; quinone compounds, acid anhydride compounds, fullerenes, and the like.
These electron accepting compounds may be used alone or in combination of two or more.

The content of the electron-accepting compound varies depending on the type of material and cannot be uniquely determined, but is preferably 0.01% by mass to 50% by mass with respect to the hole injection layer material, and 0.05% by mass. % To 20% by mass is more preferable, and 0.1% to 10% by mass is particularly preferable.
When the amount used is within the preferred range, the number of carriers in the hole injection layer is increased, so that the hole injection property and the transport property are improved. On the other hand, if the content exceeds 50% by mass, the number of carriers may be decreased, resulting in a decrease in hole injection property and transport property, which is not preferable.

<< Hole Transport Layer >>
The hole transport layer is a layer having a function of receiving holes from the anode or the anode side and transporting them to the cathode side together with the hole injection layer.
The hole transport layer may have a single layer structure or a multilayer structure composed of a plurality of layers having the same composition or different compositions.
Examples of the material for the hole transport layer and the electron-accepting compound contained include those similar to the hole injection layer.

<< Electron injection layer, electron transport layer >>
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. The electron injecting material and the electron transporting material used for these layers may be low molecular compounds or high molecular compounds. Specifically, pyridine derivatives, quinoline derivatives, pyrimidine derivatives, pyrazine derivatives, phthalazine derivatives. , Phenanthroline derivative, triazine derivative, triazole derivative, oxazole derivative, oxadiazole derivative, imidazole derivative, fluorenone derivative, anthraquinodimethane derivative, anthrone derivative, diphenylquinone derivative, thiopyrandioxide derivative, carbodiimide derivative, fluorenylidenemethane Derivatives, distyrylpyrazine derivatives, aromatic tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives and metal phthalocyanines, benzoo Sasol to various metal complexes typified benzothiazole by metal complexes having a ligand, an organic silane derivatives typified by silole is preferred.

The electron injection layer and the electron transport layer may contain an electron donating dopant.
The electron donating dopant introduced into the electron injection layer and the electron transport layer is not particularly limited as long as it has an electron donating property and has a property of reducing an organic compound, and can be appropriately selected according to the purpose. However, an alkali metal such as Li, an alkaline earth metal such as Mg, a transition metal containing a rare earth metal, a reducing organic compound, or the like is preferable. As the metal, a metal having a work function of 4.2 eV or less is particularly preferable. Specifically, Li, Na, K, Be, Mg, Ca, Sr, Ba, Y, Cs, La, Sm, Gd, Yb Etc. Examples of the reducing organic compound include nitrogen-containing compounds, sulfur-containing compounds, and phosphorus-containing compounds.
These electron donating dopants may be used alone or in combination of two or more.
The content of the electron donating dopant varies depending on the type of material, but is preferably 0.1% by mass to 99% by mass, and 1.0% by mass to 80% by mass with respect to the electron transport layer material. More preferably, it is particularly preferably 2.0% by mass to 70% by mass.

  The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .

<< Hole Block Layer, Electron Block Layer >>
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side, and is usually provided as an organic compound layer adjacent to the light emitting layer on the cathode side. .
The electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side, and is usually provided as an organic compound layer adjacent to the light emitting layer on the anode side.
Examples of the compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, and phenanthroline derivatives such as BCP.
As a compound which comprises the said electron block layer, what was mentioned as the above-mentioned hole transport material can be utilized, for example.
The average thickness of the hole blocking layer and the electron blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and particularly preferably 10 nm to 100 nm. In addition, the hole blocking layer and the electron blocking layer may have a single-layer structure made of one or more of the materials described above, or may have a multilayer structure made up of a plurality of layers having the same composition or different compositions. Good.

<< Board >>
The organic electroluminescent element is preferably provided on a substrate, and may be provided in such a manner that the electrode and the substrate are in direct contact with each other, or may be provided with an intermediate layer interposed therebetween.
There is no restriction | limiting in particular as a material of the said board | substrate, According to the objective, it can select suitably, For example, inorganic materials, such as a yttria stabilized zirconia (YSZ) and glass (an alkali free glass, soda-lime glass, etc.); Polyethylene Examples thereof include polyesters such as terephthalate, polybutylene phthalate, and polyethylene naphthalate; organic materials such as polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, and poly (chlorotrifluoroethylene).

  There is no restriction | limiting in particular about the shape of the said board | substrate, a structure, a magnitude | size, According to the use of a light emitting element, the objective, etc., it can select suitably. In general, the shape of the substrate is preferably a plate shape. The structure of the substrate may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members. Good. The substrate may be transparent or opaque, and if transparent, it may be colorless and transparent or colored and transparent.

The substrate may be provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface.
Examples of the material of the moisture permeation preventing layer (gas barrier layer) include inorganic substances such as silicon nitride and silicon oxide.
The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.

<< Protective layer >>
The organic electroluminescent element may be entirely protected by a protective layer.
The material contained in the protective layer is not particularly limited as long as it has a function of suppressing the entry of elements that promote element deterioration such as moisture and oxygen into the element. For example, metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, Ni; MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, Fe Metal oxides such as ₂ O ₃ , Y ₂ O ₃ and TiO ₂ ; Metal nitrides such as SiNx and SiNxOy; Metal fluorides such as MgF ₂ , LiF, AlF ₃ and CaF ₂ ; polyethylene, polypropylene, polymethyl methacrylate, Polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, chlorotrifluoroethylene And a copolymer of dichlorodifluoroethylene, a copolymer obtained by copolymerizing a monomer mixture containing tetrafluoroethylene and at least one comonomer, a fluorine-containing copolymer having a cyclic structure in the copolymer main chain, Examples thereof include a water-absorbing substance having a water absorption rate of 1% or more and a moisture-proof substance having a water absorption rate of 0.1% or less.

  There is no restriction | limiting in particular as a formation method of the said protective layer, According to the objective, it can select suitably, For example, a vacuum evaporation method, sputtering method, reactive sputtering method, MBE (molecular beam epitaxy) method, cluster ion beam Examples thereof include an ion plating method, a plasma polymerization method (high frequency excitation ion plating method), a plasma CVD method, a laser CVD method, a thermal CVD method, a gas source CVD method, a coating method, a printing method, and a transfer method.

-Sealing container-
The organic electroluminescent element may be entirely sealed using a sealing container. Furthermore, a moisture absorbent or an inert liquid may be sealed in the space between the sealing container and the organic electroluminescent element.
The moisture absorbent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, Examples thereof include calcium chloride, magnesium chloride, copper chloride, cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, and magnesium oxide.
The inert liquid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paraffins, liquid paraffins; fluorinated solvents such as perfluoroalkane, perfluoroamine, and perfluoroether; chlorine System solvents, silicone oils and the like.

-Resin sealing layer-
The organic electroluminescent element is preferably suppressed by sealing the element performance deterioration due to oxygen or moisture from the atmosphere with a resin sealing layer.
The resin material of the resin sealing layer is not particularly limited and may be appropriately selected depending on the purpose. For example, acrylic resin, epoxy resin, fluorine resin, silicone resin, rubber resin, ester resin , Etc. Among these, an epoxy resin is particularly preferable from the viewpoint of moisture prevention function. Among the epoxy resins, a thermosetting epoxy resin or a photocurable epoxy resin is preferable.

  There is no restriction | limiting in particular as a preparation method of the said resin sealing layer, According to the objective, it can select suitably, For example, the method of apply | coating a resin solution, the method of crimping | bonding or thermocompressing a resin sheet, vapor deposition, sputtering, etc. And a dry polymerization method.

-Sealing adhesive-
The sealing adhesive used for the organic electroluminescent element has a function of preventing intrusion of moisture and oxygen from the end portion.
As the material of the sealing adhesive, the same material as that used for the resin sealing layer can be used. Among these, an epoxy adhesive is preferable from the viewpoint of moisture prevention, and a photocurable adhesive or a thermosetting adhesive is particularly preferable.
It is preferable to add a filler to the sealing adhesive. As the filler, for _example, SiO 2, SiO (silicon oxide), SiON (silicon oxynitride), an inorganic material such as SiN (silicon nitride) are preferred. Addition of the filler increases the viscosity of the sealing adhesive, improves processing suitability, and improves moisture resistance.
The sealing adhesive may contain a desiccant. Examples of the desiccant include barium oxide, calcium oxide, and strontium oxide. The addition amount of the desiccant is preferably 0.01% by mass to 20% by mass and more preferably 0.05% by mass to 15% by mass with respect to the sealing adhesive. When the addition amount is less than 0.01% by mass, the effect of adding the desiccant is diminished, and when it exceeds 20% by mass, it is difficult to uniformly disperse the desiccant in the sealing adhesive. Sometimes.
In the present invention, it is possible to seal by applying an arbitrary amount of a sealing adhesive containing a desiccant in the previous period with a dispenser or the like, and stacking and curing the second substrate after application.

The organic electroluminescent element of the present invention may further have an electromagnetic wave absorbing layer that absorbs an electromagnetic wave having a wavelength irradiated when the luminance change pattern is formed on the light emitting surface.
When the organic electroluminescent device exposed by the electromagnetic wave irradiation has increased sensitivity to the wavelength of the irradiated electromagnetic wave, the light emitting surface of the organic electroluminescent device is exposed to light including a specific wavelength from the outside. In some cases, the brightness may decrease. Therefore, in order to prevent unintended exposure, it is preferable to provide an electromagnetic wave absorbing layer that absorbs the electromagnetic wave having the wavelength irradiated in the electromagnetic wave irradiation process on the light emitting surface of the organic electroluminescent element.

There is no restriction | limiting in particular as said electromagnetic wave absorption layer, According to the wavelength to absorb, it can select suitably, For example, a filter, a film, etc. are mentioned.
The method for installing the electromagnetic wave absorbing layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the entire organic electroluminescent element may be wrapped or the light emitting surface of the organic electroluminescent element may be covered. It may be covered.

-Drive-
The organic electroluminescent element emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. be able to.
The organic electroluminescence device can be applied to an active matrix by a thin film transistor (TFT). As the active layer of the thin film transistor, for example, amorphous silicon, high temperature polysilicon, low temperature polysilicon, microcrystalline silicon, oxide semiconductor, organic semiconductor, carbon nanotube, or the like can be used.
As the organic electroluminescent element, for example, a thin film transistor described in WO2005 / 088826 pamphlet, JP-A-2006-165529, US Patent Application Publication No. 2008 / 0237598A1, and the like can be applied.

(Method for manufacturing organic electroluminescent device)
The method for producing an organic electroluminescent element of the present invention includes at least an organic electroluminescent element production process for producing an organic electroluminescent element having a light emitting layer between an anode and a cathode, and light emission of the organic electroluminescent element. A luminance change pattern forming step of irradiating electromagnetic waves so that the luminance change pattern has an area gradation on at least a part of the surface, and further including other steps as necessary.

<Organic electroluminescence device manufacturing process>
The organic electroluminescence device manufacturing step is a step of manufacturing the organic electroluminescence device by laminating the above-described components of the organic electroluminescence device as described above. In this step, all the configurations and methods described above can be applied.

<Brightness change pattern formation process>
The luminance change pattern forming step is a step of forming the above-described luminance change pattern by electromagnetic wave irradiation. The electromagnetic wave irradiation can be performed by the above-described means and method. A method of changing the transmittance of electromagnetic wave through an exposure mask having a pattern displaying a binary value. It is preferable to carry out the method by scanning the light emitting element.
Further, in the luminance change pattern forming step, it is preferable in terms of work efficiency and cost to simultaneously perform luminance unevenness correction in the light emitting surface of the organic electroluminescent element and formation of area gradation composed of the luminance change pattern. .

<Other processes>
The manufacturing method of the organic electroluminescent element of the present invention may include a luminance unevenness correcting step of correcting luminance unevenness in the light emitting surface as another step.
As described above, the luminance unevenness correction may be performed before or after the luminance change pattern forming step, or may be performed simultaneously with the luminance change pattern forming step.

Examples of the present invention will be described below, but the present invention is not limited to these examples. However, Examples 1-4, 6, and 10 are read as reference examples.

Example 1
<Production of organic electroluminescence device>
A glass substrate with ITO having a thickness of 100 nm (substrate average thickness: 0.7 mm, Super Flat ITO, manufactured by Geomatek Co., Ltd.) was washed and sufficiently dried, and then the surface of ITO was subjected to oxygen plasma treatment. Next, the substrate was put into a vacuum deposition apparatus, and 2-TNATA was deposited so as to have a thickness of 120 nm. Next, NPD was vapor-deposited so that the thickness was 4 nm, HTL-1 was then vapor-deposited so that the thickness was 3 nm, and mCP was vapor-deposited so that the thickness was 3 nm. Next, mCP doped with 40% by mass of PT-1 was deposited as a light emitting layer so as to have a thickness of 30 nm. Furthermore, BCP was vapor-deposited so that the thickness might be 1 nm so that Balq might be 39 nm in thickness. The vapor deposition rate was 0.2 nm / s. Next, LiF was vapor-deposited so as to have a thickness of 1 nm, and finally aluminum (Al) was vapor-deposited as a cathode so as to have a thickness of 100 nm. The deposition rate of LiF was 0.02 nm / s, and the deposition rate of Al was 1 nm / s. Next, the sealing glass was adhered using a UV curable adhesive (XNR5516Z manufactured by Nagase ChemteX Corporation) to obtain a white organic electroluminescent element having a light emitting area of 15 cm × 15 cm. The structure of the finally obtained element was ITO (100) / 2-TNATA (120) / NPD (4) / HTL-1 (3) / mCP (3) / mCP + 40% PT-1 (30) / BAlq (39) / BCP (1) / LiF (1) / Al (100). The values in parentheses represent the average thickness, and the unit is “nm”.

<Electromagnetic wave irradiation>
An image obtained by binarizing the image shown in FIG. 4 using Adobe Photoshop elements 3.0 using the error diffusion method and reversing the image (FIG. 5) is an OHP sheet (VF-1100N, manufactured by KOKUYO Corporation). The ink was printed at a resolution of 200 dpi using an inkjet printer (an inkjet printer manufactured by Hewlett-Packard Company, OFFICEJET6000). The exposure mask thus manufactured expresses light and dark with area gradation. Using this as an exposure mask, it was placed on the 15 cm square white organic electroluminescent element obtained above, and placed in a discoloration tester (light source: xenon lamp) manufactured by Shinto Kagaku Co., Ltd., and irradiated with electromagnetic waves for 3 hours. When 6 V was applied to the obtained organic electroluminescent element, it was confirmed that light was emitted in the pattern of FIG. After confirming the exposed pattern, an ultraviolet cut filter (manufactured by FUJIFILM Corporation, SC-42) was attached to the surface of the substrate for observing light emission for the purpose of preventing further exposure with external light.

<Evaluation of pattern-displayed image quality>
A voltage of 4 V, 6 V, and 8 V was sequentially applied to the obtained organic electroluminescent device to display a pattern, and 10 evaluators were allowed to evaluate the image quality in the following five stages. The average value of the evaluation scores at the time of 4V application, 6V application, and 8V application was used as the evaluation score for image evaluation. The results are shown in Table 1.
〔Evaluation criteria〕
5: Very good 4: Good 3: Normal 2: Bad 1: Very bad

(Example 2)
In Example 1, an organic electroluminescent element was produced and evaluated in the same manner as in Example 1 except that the resolution at the time of printing an image on the OHP sheet was changed from 200 dpi to 50 dpi.

(Comparative Example 1)
In Example 1, instead of printing the image of FIG. 5 on an OHP sheet with an inkjet printer at a resolution of 200 dpi, the image of FIG. 5 was gravure using PET-10 made by Kurashiki Spinning Co., Ltd. (Kurabo). An organic electroluminescent element was produced and evaluated in the same manner as in Example 1 except that printing was performed.

(Example 3)
A white organic electroluminescent element was produced in the same manner as in Example 1. A semiconductor laser having an emission peak at 405 nm (Kiko Giken Co., Ltd., blue-violet semiconductor laser KLX-120 mW type) was installed on an automatically controlled xy stage (ALD-220-C2P, manufactured by Chuo Seiki Co., Ltd.). While moving the laser in the xy direction, a 405 nm electromagnetic wave was irradiated onto the light emitting surface of a 15 cm square white organic electroluminescent element, and exposed so as to form the image pattern of FIG. At this time, in the exposed portion, the laser irradiation time was set to 25 seconds. The laser was not irradiated at all in the part where the light emission was to be enhanced. In the portion irradiated with the laser, the voltage of the element increased, the amount of current flowing decreased, and the luminance decreased. After confirming the exposed pattern, an ultraviolet cut filter (manufactured by FUJIFILM Corporation, SC-42) was attached to the surface of the substrate where light emission was observed for the purpose of preventing further exposure with external light. The obtained organic electroluminescent element was evaluated in the same manner as in Example 1.

(Comparative Example 2)
A white organic electroluminescent element was produced in the same manner as in Example 1. In the same manner as in Example 3, the light emitting surface of the white organic electroluminescent element was scanned while irradiating a laser. At this time, exposure was performed so that the image shown in FIG. 4 was obtained by changing the laser irradiation time to 64 gradations. After confirming the exposed pattern, an ultraviolet cut filter (manufactured by FUJIFILM Corporation, SC-42) was attached to the surface of the substrate for observing light emission for the purpose of preventing further exposure with external light. Note that the electromagnetic wave exposure here is a pattern formation with light and shade gradations because gradation is applied to the intensity of the laser. The obtained organic electroluminescent element was evaluated in the same manner as in Example 1.

Example 4
<Production of organic electroluminescence device>
A 100 nm-thick IZO-attached film substrate (substrate: PET, average thickness 0.1 mm) was washed and sufficiently dried, and then the IZO surface was subjected to oxygen plasma treatment. Next, the substrate was put into a vacuum deposition apparatus, and the organic layer portion was deposited in the same manner as in Example 1. The vapor deposition rate was 0.2 nm / s. Next, LiF was vapor-deposited to a thickness of 1 nm, Al was vapor-deposited to a thickness of 0.5 nm, and Ag was vapor-deposited to a thickness of 20 nm. The deposition rate of LiF was 0.02 nm / s, and the deposition rates of Al and Ag were 0.5 nm / s. Next, the sealing glass was bonded using a UV curable adhesive to obtain a flexible translucent white organic electroluminescent element having a light emitting area of 15 cm × 15 cm. In addition, it was 46% when the transmittance | permeability of 500 nm of the obtained element was measured.

<Electromagnetic radiation>
In the same manner as in Example 1, an exposure mask was attached to the obtained flexible translucent white organic electroluminescent element, and an electromagnetic wave was irradiated. After confirming the exposed pattern, an ultraviolet cut filter (manufactured by FUJIFILM Corporation, SC-42) was attached to the substrate surface and the sealing substrate surface for the purpose of preventing further exposure with external light. Images of the obtained organic electroluminescent elements were evaluated in the same manner as in Example 1.

(Comparative Example 3)
In Example 4, instead of printing the image of FIG. 5 on an OHP sheet with an inkjet printer at a resolution of 200 dpi, the image of FIG. 5 was gravure using a GP-10 made by Kurashiki Boseki Co., Ltd. (Kurabo). An organic electroluminescent element was produced and evaluated in the same manner as in Example 4 except that printing (resolution: 200 dpi) was performed.

(Example 5)
After producing a white organic electroluminescent element in the same manner as in Example 1, the following luminance unevenness correction was performed.

<Brightness unevenness correction>
A voltage of 7 V was applied to the obtained white organic electroluminescent device using a source measure unit SMU-1 manufactured by Keithley Instruments Inc., and the luminance distribution in the light emitting surface of 15 cm × 15 cm was determined by Konica Minolta. The results of measurement at 5 mm intervals with CS-1000 manufactured are shown in FIG. As the portion far from the power source connection portion, luminance unevenness due to the wiring resistance of ITO was observed, and the in-plane (maximum luminance / minimum luminance) value was about 3.5.
The detected luminance unevenness was subjected to image processing into a black and white image, and an image with darker black as the luminance was weaker. An image was printed on a PET film by gravure printing to produce an exposure mask for correcting brightness unevenness. Note that gravure printing is a method in which the printing density is controlled by the amount of ink by changing the depth or size of a cell that holds ink, and this mask expresses light and dark in shades of gray. This exposure mask was affixed to the 15 cm × 15 cm white organic electroluminescent device produced above, and placed in a fading tester (light source: xenon lamp) manufactured by Shinto Kagaku Co., Ltd., and irradiated with electromagnetic waves for 2 hours. In the portion irradiated with electromagnetic waves through the exposure mask, the voltage of the device increased, the amount of current flowing decreased, and the luminance decreased. When the luminance distribution in the light emitting surface after the electromagnetic wave irradiation was measured in the same manner as described above, the luminance unevenness in the light emitting surface was corrected and (maximum luminance / minimum luminance) was 1.3 (see FIG. 3). .

  For the organic electroluminescent element subjected to the luminance unevenness correction, a pattern was formed by electromagnetic wave exposure and evaluated in the same manner as in Example 1.

(Example 6)
In Example 5, an organic electroluminescent element was produced and evaluated in the same manner as in Example 5 except that the resolution at the time of printing an image on the OHP sheet was changed from 200 dpi to 50 dpi.

(Comparative Example 4)
In Example 5, instead of printing the image of FIG. 5 on an OHP sheet with an inkjet printer at a resolution of 200 dpi, the image of FIG. 5 was gravure using PET-10 made by Kurashiki Spinning Co., Ltd. (Kurabo). An organic electroluminescent element was produced and evaluated in the same manner as in Example 5 except that printing was performed.

(Example 7)
In the same manner as in Example 5, a white organic electroluminescence device with corrected luminance unevenness was produced. A semiconductor laser having an emission peak at 405 nm (Kiko Giken Co., Ltd., blue-violet semiconductor laser KLX-120 mW type) was installed on an automatically controlled xy stage (ALD-220-C2P, manufactured by Chuo Seiki Co., Ltd.). While moving the laser in the xy direction, a 405 nm electromagnetic wave was irradiated onto the light emitting surface of a 15 cm square white organic electroluminescent element, and exposed so as to form the image pattern of FIG. At this time, in the exposed portion, the laser irradiation time was set to 25 seconds. The laser was not irradiated at all in the part where the light emission was to be enhanced. In the portion irradiated with the laser, the voltage of the element increased, the amount of current flowing decreased, and the luminance decreased. After confirming the exposed pattern, an ultraviolet cut filter (manufactured by FUJIFILM Corporation, SC-42) was attached to the surface of the substrate where light emission was observed for the purpose of preventing further exposure with external light. The obtained organic electroluminescent element was evaluated in the same manner as in Example 1.

(Comparative Example 5)
In the same manner as in Example 5, a white organic electroluminescence device with corrected luminance unevenness was produced. In the same manner as in Example 3, the light emitting surface of the white organic electroluminescent element was scanned while irradiating a laser. At this time, exposure was performed so that the image shown in FIG. 4 was obtained by changing the laser irradiation time to 64 gradations. After confirming the exposed pattern, an ultraviolet cut filter (manufactured by FUJIFILM Corporation, SC-42) was attached to the surface of the substrate for observing light emission for the purpose of preventing further exposure with external light. Note that the electromagnetic wave exposure here is a pattern formation with light and shade gradations because gradation is applied to the intensity of the laser. The obtained organic electroluminescent element was evaluated in the same manner as in Example 1.

(Example 8)
In the same manner as in Example 4, after producing a flexible translucent white organic electroluminescent element, the following luminance unevenness correction was performed.

<Brightness unevenness correction>
As a result of applying a voltage of 9 V to the obtained white organic electroluminescent element and measuring the in-plane luminance unevenness within 15 cm × 15 cm from the film substrate side with IZO at intervals of 5 mm by CS-1000 manufactured by Konica Minolta, The brightness unevenness due to the ITO wiring resistance was observed in the part far from the power supply connection part, and the (maximum brightness / minimum brightness) value in the light emitting surface was 5.1. It seems that luminance unevenness occurred more than the element of Example 1 because IZO having low conductivity was used for the electrode in order to provide flexibility.
The detected luminance unevenness is processed into a black and white image, and the image is printed by gravure printing using a GP-10 made by Kurashiki Boseki Co., Ltd. An exposure mask for correcting luminance unevenness was produced. This mask was affixed to the produced 15 cm square flexible translucent white organic electroluminescent device, placed in an amber tester (light source: mercury lamp) manufactured by Shinto Kagaku Co., Ltd., and irradiated with electromagnetic waves for 3.1 hours. In the portion irradiated with the electromagnetic wave, the voltage of the element was increased, the amount of flowing current was reduced, and the luminance was partially reduced. When the luminance distribution in the light emitting surface after the electromagnetic wave irradiation was measured, the luminance unevenness in the light emitting surface was corrected, and (maximum luminance / minimum luminance) was 1.3.

  The flexible semitransparent white organic electroluminescent element subjected to the above-described luminance unevenness correction was evaluated by performing pattern formation by electromagnetic wave exposure in the same manner as in Example 1.

(Comparative Example 6)
In Example 8, instead of printing the image of FIG. 5 on an OHP sheet with an inkjet printer at a resolution of 200 dpi, the image of FIG. 5 was gravure using a GP-10 made by Kurashiki Spinning Co., Ltd. (Kurabo). An organic electroluminescent element was produced and evaluated in the same manner as in Example 8 except that printing (resolution: 200 dpi) was performed.

Example 9
A white organic electroluminescent element was produced in the same manner as in Example 5, and luminance unevenness was measured. In order to expose the image of FIG. 4 to the white organic electroluminescent element, the image (FIG. 6) is printed on the PET film by gravure printing using GP-10 manufactured by Kurashiki Boseki Co., Ltd. (Kurabo), and an exposure mask for correcting luminance unevenness. A mask for image exposure was also produced. This mask is printed with both a grayscale pattern for correcting the luminance unevenness of the organic electroluminescence device and an area grayscale pattern for displaying a desired fixed display image. It is designed so that both unevenness correction and pattern exposure can be performed. This mask was affixed to the white organic electroluminescent element, placed in an amber tester (light source: xenon lamp) manufactured by Shinto Kagaku Co., Ltd., and irradiated with electromagnetic waves for 2 hours. In the portion irradiated with electromagnetic waves through the exposure mask, the voltage of the element increased, the amount of flowing current decreased, and the luminance partially decreased. The obtained image was evaluated in the same manner as in Example 1.

(Comparative Example 7)
In the ninth embodiment, instead of performing gravure printing on both the grayscale pattern for correcting the luminance unevenness and the area grayscale pattern for displaying the desired fixed display image, the light and shade for correcting the brightness unevenness is used. Evaluation was performed in the same manner as in Example 9 except that both a gradation pattern and a gradation pattern for displaying a desired fixed display image were gravure-printed to produce an exposure mask for correcting brightness unevenness and an image exposure mask. did.

  Table 1 below shows the types of gradations, forms of electromagnetic wave irradiation, element properties, and image quality evaluation results in Examples 1 to 9 and Comparative Examples 1 to 7.

(Example 10)
In Example 1, a white organic electroluminescent element was produced in the same manner as in Example 1 except that the size of the substrate, the sealing glass, and the like was changed so that the light emitting surface was 2 mm × 2 mm. In addition, an area gradation mask (opening area ratio 50%) printed on an OHP sheet (manufactured by KOKUYO Corporation, VF-1100N) at 200 dpi using an inkjet printer (inkjet printer manufactured by Hewlett-Packard Company, OFFICEJET6000) was prepared. The area gradation mask was set so as to cover the entire light emitting surface 2 mm × 2 mm of the obtained device, and electromagnetic wave irradiation (exposure test) was performed in the same manner as the electromagnetic wave irradiation procedure of Example 1. The device was manufactured and the exposure test was independently performed five times. The luminance of the element was measured before and after exposure when 7V or 10V was applied. The results are shown in Table 2. The “average luminance reduction rate” in Table 2 represents the ratio of the average luminance of the element after irradiation with the electromagnetic wave when the average luminance of the element not irradiated with the electromagnetic wave is 1 under the condition of applying equal voltage.

(Comparative Example 8)
In Example 1, a white organic electroluminescent element was produced in the same manner as in Example 1 except that the size of the substrate, sealing glass, and the like was changed so that the light emitting surface was 2 mm × 2 mm. In addition, a gray scale mask equivalent to 200 dpi (gravitational transmittance of about 365% at a wavelength of 365 nm) obtained by gravure printing on a PET film using GP-10 manufactured by Kurashiki Boseki Co., Ltd. (Kurabo) is used. It was installed so as to be covered and irradiated with electromagnetic waves from a xenon lamp for 15 minutes. This device fabrication and exposure test were performed independently 5 times. The luminance of the element was measured before and after exposure when 7V or 10V was applied. The results are shown in Table 2. The exposure time of the gray gradation was a time 2,000 cd / ^{m 2} is reduced to about 1,000 cd / ^{m 2.}

From the results of Example 1, Example 2, and Comparative Example 1, the image quality of the organic electroluminescent element on which the image pattern was formed by irradiating the electromagnetic wave for forming the luminance change pattern using the exposure mask of area gradation. Was able to improve. Further, in the electromagnetic wave exposure, the image quality could be further improved by setting the exposure mask resolution to 200 dpi or more.
From the results of Example 4, the same effect as described above was obtained even in a translucent element having flexibility.
From the results of Example 3 and Comparative Example 2, the image quality of the organic electroluminescent device is improved by changing the laser irradiation in binary so that the luminance change pattern becomes an area gradation, and scanning the light emitting surface for exposure. I was able to increase it.
In Examples 5 to 8, by performing the luminance unevenness correction, the image quality could be further improved as compared with the case where the luminance unevenness correction was not performed (Examples 1 to 4).
In the ninth embodiment, by using an exposure mask that simultaneously performs luminance unevenness correction and area gradation luminance change pattern formation, organic electroluminescence with less luminance unevenness and a high-quality image pattern displayed by a single exposure. An element was obtained.

  From the comparison between Example 10 and Comparative Example 8, when the brightness of the element was changed in the area gradation, it was possible to change to any luminance without depending on the voltage, and the electromagnetic wave irradiation was repeated. While the variation in brightness between elements at the time was small, when the brightness of the element was changed in grayscale, the rate of decrease differed depending on the driving voltage for each element, and electromagnetic wave irradiation was repeated. It can be seen that the variation in luminance between elements at the time increases. Therefore, when patterning an organic electroluminescent element with electromagnetic waves, it is preferable to carry out with area gradation.

  By the manufacturing method of the present invention, it is possible to obtain an organic electroluminescence device in which a desired luminance change pattern is formed more easily and with a good image quality and good reproducibility without being affected by the voltage-current characteristics of the device. it can. And the organic electroluminescent element of this invention can be utilized suitably for a display element, a display, an electrophotography, a sign, a signboard, an interior, etc.

Claims (14)

Having a light emitting layer between the anode and the cathode;
Have a halftone dot composed of luminance change pattern of changing the brightness in at least a part of the light emitting surface,
A resolution of the luminance change pattern is 100 dpi or more;
The organic electroluminescent device luminance unevenness in the light emission surface is irradiated with electromagnetic waves, it characterized that you have been corrected.   The organic electroluminescence device according to claim 1, wherein the method of forming the luminance change pattern is electromagnetic wave irradiation. The organic electroluminescence device according to claim 2, wherein the electromagnetic wave irradiation in the formation of the luminance change pattern is performed through an exposure mask having a pattern in which a change in electromagnetic wave transmittance is displayed in binary. The organic electroluminescence device according to claim 2, wherein the electromagnetic wave irradiation in the formation of the luminance change pattern is performed by scanning the organic electroluminescence device while being changed in binary. The organic electroluminescent element according to any one of claims 2 to 4, wherein a drive voltage of a portion irradiated with an electromagnetic wave in forming a luminance change pattern is increased and a current amount is decreased. The amount of current (A) that flows per area when a specific voltage is applied to a portion irradiated with an electromagnetic wave in the formation of a luminance change pattern, and the case where the same voltage as the voltage is applied to a portion that is not irradiated with an electromagnetic wave The organic electroluminescent element according to any one of claims 2 to 5, wherein a ratio (B / A) to a current amount (B) flowing per area is 3 or more. The organic electroluminescent element according to claim 1, wherein at least one of the anode and the cathode is a metal oxide electrode. The organic electroluminescent element according to any one of claims 1 to 7, wherein the visible light transmittance is 20% or more. The organic electroluminescent element according to claim 1, which has flexibility. The organic electroluminescent element according to any one of claims 2 to 9, further comprising an electromagnetic wave absorbing layer that absorbs an electromagnetic wave having a wavelength used in electromagnetic wave irradiation in forming a luminance change pattern on a light emitting surface. An organic electroluminescence device production process for producing an organic electroluminescence device comprising a light emitting layer between an anode and a cathode;
A luminance change pattern forming step of irradiating an electromagnetic wave so that a luminance change pattern has an area gradation on at least a part of a light emitting surface of the organic electroluminescent element, and a resolution of the luminance change pattern is 100 dpi or more;
And a step of correcting luminance unevenness in the light emitting surface by irradiating electromagnetic waves. The method for producing an organic electroluminescent element according to claim 11, wherein the electromagnetic wave irradiation in the step of forming the luminance change pattern is performed through an exposure mask having a pattern in which a change in transmittance of the electromagnetic wave is displayed in binary. The method of manufacturing an organic electroluminescent element according to claim 11, wherein the electromagnetic wave irradiation in the step of forming the luminance change pattern is performed by changing the binary value and scanning the organic electroluminescent upper element. The organic electroluminescence device according to any one of claims 11 to 13, wherein in the luminance change pattern forming step, the luminance unevenness correction in the light emitting surface of the organic electroluminescence device and the formation of the area gradation composed of the luminance change pattern are simultaneously performed. Manufacturing method.