JP5003594B2 - Organic EL device - Google Patents

Description

  The present invention relates to an organic EL device including a plurality of light emitting layers containing a hole transporting material, an electron transporting material, and a dopant.

  Conventionally, in order to improve luminance life performance, an organic EL element containing a hole transporting material, an electron transporting material, and a dopant as a light emitting layer has been proposed in Patent Document 1, for example.

  This organic EL element exhibits a bipolar property having transportability for both electrons and holes as carriers by containing a hole transporting material and an electron transporting material. This bipolar property changes depending on the mixing ratio of the hole transporting material and the electron transporting material. That is, when the bipolar performance changes, the recombination region of electrons and holes changes.

The light emitting layer having such bipolar performance is formed by a vacuum deposition method in which an organic material sublimated from a deposition source is deposited on a glass substrate.
JP 2006-186385 A

  However, in the vacuum deposition method, since the distance between the deposition source and the glass substrate is not uniform within the glass substrate surface, the film thickness distribution of the light emitting layer occurs in the glass substrate. Due to this difference in film thickness, a distribution of the mixing ratio of the hole transporting material and the electron transporting material occurs in the glass substrate. Furthermore, when there are two or more light emitting layers, the recombination distribution also changes for each light emitting layer, and as a result, the luminance intensity ratio from each light emitting layer changes and the luminance as an organic EL element changes. . Therefore, when two or more light emitting layers having different emission colors are formed on the organic EL element, the chromaticity of light emitted from the organic EL element also changes.

  Specifically, when the hole transporting material ratio in the light emitting layer increases, that is, the electron transporting material ratio decreases, the hole mobility as the light emitting layer increases and the electron mobility decreases. That is, the recombination distribution is shifted to the electron injection side of the light emitting layer. Conversely, when the hole transporting material ratio decreases, that is, the electron transporting material ratio increases, the recombination distribution shifts to the hole injection side of the light emitting layer.

  From the above, when the ratio of the hole transporting material in the plurality of light emitting layers increases uniformly, the recombination distribution shifts to the hole injection side of the light emitting layer. The chromaticity becomes stronger. On the contrary, when the ratio of the electron transporting material in the plurality of light emitting layers increases uniformly, the recombination distribution shifts to the electron injection side of the light emitting layer, so that the chromaticity of the light emitting layer arranged on the electron injection side becomes strong. End up.

  For example, by having a blue and red light emitting layer, in an organic EL element that emits white light by mixing these two colors, if the light emission intensity of the blue light emitting layer is relatively strong, the light emission changes to blue. On the contrary, if the light emission intensity of the red light emitting layer is relatively increased, the light emission changes to white light emission exhibiting red. In particular, the change in the bipolar performance due to the change in the mixing ratio of the hole transporting material and the electron transporting material makes it very easy to change the light emission intensity balance between the plurality of light emitting layers.

  As described above, in an organic EL having a plurality of light emitting layers containing a hole transporting material, an electron transporting material, and a dopant and having different emission colors in each light emitting layer, many organic EL elements are provided on the glass substrate. When formed, the change in the emission intensity balance of each light emitting layer due to the change in the mixing ratio of the hole transporting material and the electron transporting material causes variation in chromaticity in each organic EL element.

  In view of the above points, the present invention is one of a large number of organic EL elements formed on a substrate and having two or more light-emitting layers. However, it is an object to reduce variation in chromaticity due to variation in the mixing ratio between the hole transporting material and the electron transporting material.

In order to achieve the above object, the invention according to claim 1 is one of many formed on one substrate (10) and contains a hole transporting material, an electron transporting material, and a dopant. A plurality of light emitting layers (40, 50) are provided, and each of the plurality of light emitting layers (40, 50) is an organic EL element that emits different emission colors, and is one of the plurality of light emitting layers (40, 50). The content ratio of the hole transport material or the electron transport material in M is defined as M, the content ratio of the dopant is defined as Md, and the emission chromaticity of all the plurality of light emitting layers (40, 50) is defined as WCIE (x, y). From the relationship between the content M of the hole transporting material or the electron transporting material M, the content Md of the dopant, and the emission chromaticity WCIE (x, y), a correlation function obtained by multiple regression analysis is expressed as WCIEx = fx (M, Md), WCIEy = fy M, Md), and a hole with which a target emission chromaticity can be obtained when the content M of the hole transport material or the electron transport material in the plurality of light emitting layers (40, 50) is a target center value. The value of the content of the transport material or the electron transport material is defined as M _0, and the target emission chromaticity when the dopant content Md in the plurality of light emitting layers (40, 50) is the target center value. Is defined as Md ₀ , the content M of the hole transporting material or the electron transporting material and the content of the dopant in all the light emitting layers (40, 50). Md is
(Equation 1)
_{| Fx (M0, Md 0)} -fx (M, Md) | ≦ 0.005
And,
(Equation 2)
_{| Fy (M0, Md 0)} -fy (M, Md) | ≦ 0.005
It is characterized by satisfying.

  Thus, each content in each light emitting layer (40, 50) is combined by combining the film thickness distribution of each material which comprises each light emitting layer (40, 50) so that the said number 1 and number 2 may be satisfy | filled. The distribution of the ratios M and Md in the substrate (10) can be reversed to cancel the chromaticity variation. Therefore, even if the organic EL device is one of many formed on the substrate (10), variation in chromaticity due to variation in the mixing ratio of the hole transporting material and the electron transporting material can be reduced. .

  The thickness distribution shape of each material constituting each light emitting layer (40, 50) can be controlled by adjusting the direction of the evaporation source center with respect to the substrate (10). In general, film formation is performed while rotating the substrate (10) in order to reduce the film thickness distribution in the substrate (10). At this time, for example, the deposition source center is set to the center of the substrate (10). If it is directed, the center of the substrate (10) is the thickest and convex shape, and if it is directed to the periphery of the substrate (10), the center of the substrate (10) is the thinnest and concave shape. Thus, if the film thickness distribution of each material constituting each light emitting layer (40, 50) is controlled, the distribution of each content rate M, Md can be arbitrarily controlled.

  Here, it is preferable that the variation in chromaticity of individual organic EL elements formed in large numbers on the substrate (10) is ± 0.02 or less. The chromaticity affects not only the relative intensity between the light emitting layers (40, 50) but also the interference effect, and the interference effect is also affected by the film thickness of the organic layer other than the light emitting layer (40, 50). It is preferable that the chromaticity variation derived from at least the contents M and Md of each light emitting layer (40, 50) is suppressed to ± 0.005 or less.

A multiple regression analysis method can be used for deriving the correlation function (prediction formula). The procedure for deriving the correlation function by a specific multiple regression analysis method is shown below.
1. 2. Experimentally confirm the emission color of the organic EL element when each parameter is changed. Perform multiple regression analysis using all data in 2.1. 3. Partial regression coefficient for each parameter is calculated by multiple regression analysis. The product of each parameter and the corresponding partial regression coefficient is simply accumulated for all parameters. Since multiple regression analysis is a linear linear combination, the parameter does not show a linear correlation with the emission color of the organic EL element. If it is included, the accuracy is significantly reduced. Such parameters may be used after being converted so as to have a linear correlation. For example, in the case of having an exponential function correlation, the logarithm logM of the parameter M can be used.

  As in the second aspect of the present invention, the plurality of light emitting layers (40, 50) may be formed by a co-evaporation method using a plurality of independent evaporation sources.

  In the invention according to claim 3, the plurality of light emitting layers (40, 50) include a hole transport layer (30) formed of a hole transport material and an electron transport layer (70) formed of an electron transport material. ), And the hole-transporting material contained in the plurality of light-emitting layers (40, 50) is the same as the hole-transporting material forming the hole-transporting layer (30). The electron transporting material contained in the layers (40, 50) is the same as the electron transporting material forming the electron transporting layer (70).

  Thereby, the energy barrier in the boundary of a light emitting layer (40,50) and a positive hole transport layer (30) and the boundary of a light emitting layer (40,50) and an electron carrying layer (70) can be reduced. Therefore, it is possible to easily control the parameter of the content rate in the organic EL element.

The invention according to claim 4 is one of many formed on the substrate (10), and has a plurality of light emitting layers (40, 50) containing a hole transporting material, an electron transporting material and a dopant. The plurality of light emitting layers (40, 50) are organic EL elements that emit different emission colors, and the hole transporting material or the electron transporting property in one of the plurality of light emitting layers (40, 50). The material content is defined as M, the dopant content is defined as Md, and the light emission chromaticity of all the light emitting layers (40, 50) is defined as WCIE (x, y). From the relationship between the material content M, the dopant content Md, and the emission chromaticity WCIE (x, y), the correlation functions obtained by multiple regression analysis are WCIEx = fx (M, Md), WCIEy = fy ( M, Md) Content ratio of hole transporting material or electron transporting material in which target emission chromaticity is obtained when content ratio M of hole transporting material or electron transporting material in layer (40, 50) is a target central value Is defined as M _0, and when the dopant content Md in the plurality of light emitting layers (40, 50) is the target central value, the target dopant chromaticity can be obtained. When the value is defined as Md ₀ , when the plurality of light emitting layers (40, 50) are formed on the substrate (10) by a co-evaporation method using independent vapor deposition sources, the plurality of light emitting layers (40, 50). The hole transport material or electron transport material content M and dopant content Md in all of the substrate (10) are:
(Equation 3)
_{| Fx (M0, Md 0)} -fx (M, Md) |> 0.005
Or
(Equation 4)
_{| Fy (M0, Md 0)} -fy (M, Md) |> 0.005
When the distribution satisfies the above, one of the many formed in the substrate (10) by controlling the combination of the distribution,
(Equation 5)
_{| Fx (M0, Md 0)} -fx (M, Md) | ≦ 0.005
And,
(Equation 6)
_{| Fy (M0, Md 0)} -fy (M, Md) | ≦ 0.005
It is characterized by satisfying.

  According to this, even if it is a light emitting layer (40, 50) which cannot make the film thickness distribution of each material which comprises each light emitting layer (40, 50) which satisfy | fills the said Formula 3 or Formula 4 cannot be made small, By combining the chromaticity variations, it is possible to cancel the chromaticity variation so as to satisfy the expressions 5 and 6. Therefore, even if the organic EL device is one of many formed on the substrate (10), variation in chromaticity due to variation in the mixing ratio of the hole transporting material and the electron transporting material can be reduced. .

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view of an organic EL device according to an embodiment of the present invention. As shown in this figure, the organic EL element S1 includes a transparent conductive material such as an indium-tin oxide (hereinafter referred to as ITO) on a substrate 10 (hereinafter referred to as a glass substrate) made of transparent glass or the like. An anode 20 made of a film is formed. On the anode 20, a hole transport layer 30 made of a hole transport material such as a tertiary amine compound is formed.

  Here, when an ITO film is used as the anode 20, the average surface roughness Ra of the ITO film is preferably 2 nm or less, and the 10-point average surface roughness Rz is preferably 20 nm or less. These surface roughness Ra and Rz are defined in JIS (Japanese Industrial Standard).

  On the hole transport layer 30, a hole transport material made of a tertiary amine compound and an electron transport material are used as a host material, and a light emitting additive material is mixed as a dopant into the first material. A light emitting layer 40 is formed. Furthermore, a second light emitting layer 50 is formed on the first light emitting layer 40 by mixing a dopant different from the dopant contained in the first light emitting layer 40.

  Since the first light emitting layer 40 and the second light emitting layer 50 are mixed in different dopants, the light emission colors thereof are different from each other. Further, as the hole transporting material contained in each of the light emitting layers 40 and 50, it is preferable to use a hole transporting material made of a tertiary amine compound used in the hole transporting layer 30.

  On the second light emitting layer 50, a hole blocking layer 60 made of an electron transporting material is formed. As the electron transporting material in the hole blocking layer 60, it is preferable to use the electron transporting material contained in each light emitting layer and 50. On the hole blocking layer 60, an electron transport layer 70 made of an electron transport material such as tris (8-quinolinolato) aluminum (hereinafter referred to as Alq3) is formed.

  As described above, the hole transporting material contained in each light emitting layer 40, 50 is the same as the hole transporting material forming the hole transporting layer 30, and the electrons contained in each light emitting layer 40, 50 are the same. Since the transport material is the same as the electron transport material forming the electron transport layer 70, the boundary between each light emitting layer 40, 50 and the hole transport layer 30, or each light emitting layer 40, 50 and the electron transport layer 70. The energy barrier at the boundary can be reduced. This facilitates control of the mobility of electrons and holes.

  Further, an electron injection layer 80 made of LiF (lithium fluoride) or the like is formed on the electron transport layer 70, and a cathode 90 made of a metal such as Al is formed thereon.

  Thus, the hole transport layer 30, the first light emitting layer 40, the second light emitting layer 50, the hole blocking layer 60, the electron transport layer 70, and the electron injection layer 80 are laminated between the pair of electrodes 20 and 90. The organic EL element S1 is configured. The above is the overall configuration of the organic EL element S1 according to the present embodiment.

  In such an organic EL element S1, an electric field is applied between the anode 20 and the cathode 80, holes are injected from the anode 20, and electrons are injected and transported from the cathode 80 to the light emitting layers 40 and 50, respectively. Electrons and holes are recombined in the first light emitting layer 40 and the second light emitting layer 50, and the light emitting layers 40 and 50 emit light by the energy of the recombination. And the emitted light is taken out from the glass substrate 10 side, for example, and is visually recognized.

  The organic EL element S1 is manufactured by sequentially forming the layers 20 to 90 on the glass substrate 10 by sputtering, vapor deposition, or the like. Here, the organic layers such as the hole transport layer 30, the light emitting layers 40 and 50, the hole blocking layer 60, and the electron transport layer 70 are formed by vapor deposition.

In the present embodiment, the organic EL element S1 has a hole transport material or electron transport material content in one of the light emitting layers 40 and 50 as M, a dopant content as Md, The emission chromaticity of all the light emitting layers 40 and 50 is defined as WCIE (x, y), the content M of the hole transporting material or the electron transporting material, the content Md of the dopant, and the emission chromaticity WCIE (x , Y), the correlation function obtained by the multiple regression analysis is defined as WCIEx = fx (M, Md), WCIEy = fy (M, Md), and the hole transporting material in each of the light emitting layers 40, 50 is defined. Alternatively, when the content M of the electron transporting material is the target central value, the value of the content of the hole transporting material or the electron transporting material that provides the target emission chromaticity is defined as M _0, and each light emitting layer The content of dopant in 40 and 50 When Md ₀ is defined as the value of the dopant content at which the target emission chromaticity is obtained when Md is the target center value, the hole transport material or the electron transport property in all of the light emitting layers 40 and 50 is defined. The content M of the material and the content Md of the dopant are
(Equation 7)
| Fx (M ₀ , Md ₀ ) −fx (M, Md) | ≦ 0.005
And,
(Equation 8)
| Fy (M ₀ , Md ₀ ) −fy (M, Md) | ≦ 0.005
Meet.

  The inventors derived Equation 7 and Equation 8 as follows. Hereinafter, the derivation of the correlation function (prediction formula) will be described.

  First, Study Example 1 will be described. In Study Example 1, Compound 1, which is a tertiary amine compound, was formed as a hole transport layer 30 on the anode 20 to a thickness of 75 nm. On the hole transport layer 30, as the first light emitting layer 40, the compound 1 which is a tertiary amine compound shown in FIG. 2 and the compound 2 which is an anthracene derivative having electron transport properties shown in FIG. Compound 3 which is a yellow light emitting additive material shown in FIG. 5 was formed to a thickness of 20 nm with a weight ratio of 53: 47: 3.1, respectively. Further, as the second light emitting layer 50 on the first light emitting layer 40, the compound 1 which is a tertiary amine compound, the compound 2 which is an anthracene derivative having an electron transporting property, and the compound 4 which is a blue light emitting additive material shown in FIG. And 34 nm in a weight ratio of 80: 20: 3.1, respectively.

  And 20 nm of compounds 2 as an electron transport material were formed as a hole-blocking layer 60 on what was formed as mentioned above. Further, 12 nm of Alq3 was formed as the electron transport layer 70 on the hole blocking layer 60. In addition, LiF was deposited to 0.5 nm on the electron injection layer 80 and Al was deposited to 200 nm on the cathode 90, and was sealed with a sealing can in a dry nitrogen atmosphere to obtain an organic EL element S1. The organic EL element S1 created under these conditions is used as a reference condition.

  As Study Example 2, an organic EL element S1 in which the weight ratio of Compound 1, Compound 2, and Compound 3 in the first light-emitting layer 40 was 45: 55: 3.1 with respect to Study Example 1 was formed. Other configurations are the same as those in the first study example. The same applies to the following study examples.

  As Study Example 3, compared to Study Example 1, an organic EL element S1 in which the weight ratio of Compound 1, Compound 2, and Compound 3 in the first light emitting layer 40 was 62: 38: 3.1 was formed.

  As Study Example 4, an organic EL element S1 in which the weight ratio of Compound 1, Compound 2, and Compound 4 in the second light-emitting layer 50 was 75: 25: 3.1 with respect to Study Example 1 was formed.

  As Study Example 5, an organic EL element S1 in which the weight ratio of Compound 1, Compound 2, and Compound 4 in the second light-emitting layer 50 was 85: 15: 3.1 with respect to Study Example 1 was formed.

  As Study Example 6, an organic EL element S1 in which the weight ratio of Compound 1, Compound 2, and Compound 3 in the first light emitting layer 40 was 53: 47: 5.3 with respect to Study Example 1 was formed.

  As Study Example 7, an organic EL element S1 in which the weight ratio of Compound 1, Compound 2, and Compound 3 in the first light-emitting layer 40 was 53: 47: 2.0 with respect to Study Example 1 was formed.

  As Study Example 8, an organic EL element S1 in which the weight ratio of Compound 1, Compound 2, and Compound 4 in the second light emitting layer 50 was 80: 20: 5.5 with respect to Study Example 1 was formed.

  As Study Example 9, an organic EL element S1 in which the weight ratio of Compound 1, Compound 2, and Compound 4 in the second light-emitting layer 50 was 80: 20: 1.4 with respect to Study Example 1 was formed.

For the organic EL element S1 obtained in these examination examples 1 to 9, a desired concentration is obtained from the absorption spectrum of the single layer film of each of the first light emitting layers 40 and 50 formed side by side with each organic EL element S1. It was confirmed that. FIG. 6 shows the chromaticity when the organic EL element S1 obtained in the examination examples 1 to 9 is caused to emit light with a luminance of 920 cd / m ² under a driving condition of 1/64 duty in a room temperature environment.

  Further, based on the above results, the content of Compound 1 in each of the light emitting layers 40 and 50 (ratio of Compound 1 with respect to the total amount of Compound 1 and Compound 2), the content of Compound 3 in the first light emitting layer 40 (Compound) Focusing on four parameters such as the ratio of compound 3 to the total amount of 1, 1, 2, and 3), and the content of compound 4 in the second light emitting layer 50 (the ratio of compound 4 to the total amount of compound 1, compound 2, and compound 4) FIG. 7 shows partial regression coefficients for each parameter when multiple regression analysis is performed.

Based on the results of the multiple regression analysis described above, the correlation formula (prediction formula) of chromaticity WCIE (x, y) is expressed by the following formulas (9) and (10).
(Equation 9)
WCIEx = {(− 1.114 × M ₄₀ ) + (− 1.78 × M ₅₀ ) + (− 0.611 × Md ₄₀ ) + (− 2.473 × Md ₅₀ ) +406.129} / 1000
(Equation 10)
WCIEy = {(− 0.227 × M ₄₀ ) + (− 1.281 × M ₅₀ ) + (− 0.851 × Md ₄₀ ) + (4.127 × Md ₅₀ ) +359.415} / 1000
Here, M ₄₀ is the content of compound 1 in the first light emitting layer 40, M ₅₀ is the content of compound 1 in the second light emitting layer 50, and Md ₄₀ is the content of compound 3 in the first light emitting layer 40. , Md ₅₀ indicates the content of compound 4 in the second light emitting layer 50. The content M of the hole transport material and the electron transport material can be measured by ultraviolet / visible spectroscopy or infrared spectroscopy. Specifically, it can be calculated by measuring each peak intensity ratio derived from the hole transport material and the electron transport material in the spectrum. The dopant content Md can be measured by fluorescence spectroscopy. Specifically, it can be calculated by measuring the peak position or fluorescence lifetime of the fluorescence spectrum.

  Subsequently, the film thickness distribution in the glass substrate 10 by a vapor deposition source having a general crucible shape as a vapor deposition source of the vapor deposition apparatus will be described. The glass substrate 10 here refers to a substrate on which many organic EL elements S1 are formed.

  A vapor deposition source having a general crucible shape can be regarded as a point source because it is much smaller than the substrate size and further away from the substrate. For this reason, the film deposited on the substrate always has a concentric film thickness distribution. As shown in FIG. 8A, generally, in order to reduce the film thickness distribution in the glass substrate 10, the glass substrate 10 is rotated during vapor deposition. For this reason, if the center line of the vapor deposition source 100 is directed to the center of the glass substrate 10, the center of the glass substrate 10 is thickest and has a concentric film thickness distribution that becomes thinner toward the periphery. On the other hand, as shown in FIG. 8B, if the center line of the vapor deposition source 100 is directed to the periphery of the glass substrate 10, the thickness of the doughnut-shaped film is thin at the center of the glass substrate 10 and thick at the periphery. Will have a distribution.

  In the first light-emitting layer 40 and the second light-emitting layer 50 formed by the co-evaporation method using the plurality of vapor deposition sources 100 having such a concentric film thickness distribution, for example, the distribution of the compound 1 content in the glass substrate 10 Can be easily understood as being concentric.

  And organic electroluminescent element S1 was formed on the conditions of the study example 1 on the glass substrate 10 of 300 mm x 400 mm. At this time, the target weight ratio of each compound in the first light emitting layer 40 and the second light emitting layer 50 was adjusted to be an average value of the distribution in the substrate of the glass substrate 10. Hereinafter, this adjustment is referred to as a comparative example.

  The content ratio of compound 1 in the first light emitting layer 40 and the second light emitting layer 50 in this comparative example, the content ratio of compound 3 in the first light emitting layer 40, and the content ratio of compound 4 in the second light emitting layer 50 Was the highest concentric shape at the substrate center of the glass substrate 10. 9 shows the in-substrate distribution width of the glass substrate 10 of the content ratio of the compound 1, the content ratio of the compound 3, and the content ratio of the compound 4 in the first light emitting layer 40 and the second light emitting layer 50 at this time.

Then, from the distribution in the substrate of the table shown in FIG. 7, it is predicted that the chromaticity is most shifted from the target center at the substrate periphery and the center of the glass substrate 10. 11 and number 12 were calculated.
(Equation 11)
| Fx (M ₀ , Md ₀ ) −fx (M, Md) | = 0.0003> 0.005
(Equation 12)
| Fy (M ₀ , Md ₀ ) −fy (M, Md) | = 0.014 <0.005
Thereby, it can be predicted that Expression 7 is not satisfied with respect to Expression 11. Then, in the actually formed organic EL element S1, the maximum deviation amount (maximum variation width) from the central value of chromaticity between the organic EL elements S1 existing in the glass substrate 10 was evaluated, and ΔWCIEx = 0. .007 and ΔWCIEy = 0.0012, and the expressions 7 and 8 were not satisfied.

  Therefore, except for adjusting the distribution width in the substrate of the glass substrate 10 of the content ratio of the compound 1 in the first light emitting layer 40 and the second light emitting layer 50 so as to satisfy the equations 7 and 8, in the comparative example, Similarly, organic EL element S1 was formed in the glass substrate 10 of 300 mm x 400 mm. The crucible shape was changed as the adjustment of the distribution ratio of the compound 1 in the substrate. The table 1 in FIG. 10 shows the content distribution width of the compound 1 in the substrate in the first light-emitting layer 40 and the second light-emitting layer 50 after adjustment.

Then, from the distribution in the substrate of the table shown in FIG. 7, it is predicted that the chromaticity is most deviated from the target center at the substrate periphery and the center of the glass substrate 10, and from the calculation using Equations 9 and 10, the following Equation 13 is obtained. And the number 14 was obtained.
(Equation 13)
| Fx (M ₀ , Md ₀ ) −fx (M, Md) | = 0.004 <0.005
(Equation 14)
| Fy (M ₀ , Md ₀ ) −fy (M, Md) | = 0.0001 <0.005
According to this, it can be predicted that Expression 7 and Expression 8 are satisfied. When the maximum amount of deviation (maximum variation width) from the central value of chromaticity between the organic EL elements S1 existing in the glass substrate 10 was evaluated in the actually formed organic EL element S1, ΔWCIEx = 0.411. ΔWCIEy = 0.0001, which was good.

  On the other hand, in the comparative example, the position of the vapor deposition source 100 was adjusted so that the content ratio of the compound 1 in the second light emitting layer 50 was the lowest concentric shape at the center of the glass substrate 10. Then, an organic EL element S1 was formed on the 300 mm × 400 mm glass substrate 10 under the conditions of Study Example 1. At this time, the target weight ratio of each compound in the first light emitting layer 40 and the second light emitting layer 50 was adjusted to be an average value of the distribution in the substrate of the glass substrate 10. FIG. 11 shows the content-in-substrate distribution width of the compound 1 in the first light-emitting layer 40 and the second light-emitting layer 50 after adjustment.

From the distribution in the substrate shown in FIG. 7, it is predicted that the chromaticity is most deviated from the target center at the substrate periphery and the center of the glass substrate 10, and from the calculations using Equations 9 and 10, the following Equations 15 and 16 was obtained.
(Equation 15)
| Fx (M ₀ , Md ₀ ) −fx (M, Md) | = 0.002 <0.005
(Equation 16)
| Fy (M ₀ , Md ₀ ) −fy (M, Md) | = 0.0037 <0.005
According to this, it can be predicted that Expression 7 and Expression 8 are satisfied. When the maximum deviation amount (maximum variation width) from the central value of chromaticity between the organic EL elements S1 existing in the glass substrate 10 was evaluated in the actually formed organic EL element S1, ΔWCIEx = 0.0005. ΔWCIEy = 0.0038, which was favorable.

  In the example shown in FIG. 11, the distribution width of the content rate is the same as that of the comparative example, but a good result is obtained by changing only the distribution shape by adjusting the position of the vapor deposition source 100. In order to improve the distribution width by changing the shape of the vapor deposition source 100 or increasing the distance from the glass substrate 10, it is necessary to increase the vapor deposition rate. To increase the vapor deposition rate, the material heating temperature is increased. Although there is a possibility of promoting decomposition, there is no fear of the above method.

  As described above, the present embodiment is characterized in that each content rate satisfies Expressions 7 and 8. That is, by combining the distributions as shown in FIG. 8A and FIG. 8B, the chromaticity variation in each of the light emitting layers 40 and 50 can be offset. Therefore, even if the organic EL element S1 is one of many formed on the glass substrate 10, the variation in chromaticity due to the variation in the mixing ratio of the hole transporting material and the electron transporting material can be reduced. .

(Second Embodiment)
In the present embodiment, only different parts from the first embodiment will be described. In the first embodiment, the distribution in the substrate can be controlled so that Expressions 7 and 8 are satisfied by the combination of distributions, but the distribution in the substrate cannot be controlled so that Expressions 7 and 8 are satisfied. is there.

Therefore, in the present embodiment, the hole transport material or the electron transport material content M and the dopant content Md in each of the light emitting layers 40 and 50 are as follows.
(Equation 17)
| Fx (M ₀ , Md ₀ ) −fx (M, Md) |> 0.005
Or
(Equation 18)
| Fy (M ₀ , Md ₀ ) −fy (M, Md) |> 0.005
When the distribution satisfies the above condition, that is, when the tolerance of the distribution in the substrate in the glass substrate 10 is large, the combination of distributions is controlled to cancel the distribution tolerance, thereby forming a large number in the glass substrate 10. One of the formed organic EL elements S1 is
(Equation 19)
| Fx (M ₀ , Md ₀ ) −fx (M, Md) | ≦ 0.005
And,
(Equation 20)
| Fy (M ₀ , Md ₀ ) −fy (M, Md) | ≦ 0.005
To satisfy.

As a result, when the deviation of the content ratios M and Md with respect to the target center value M ₀ cannot be reduced, by using the fact that the deviation is large, by combining distributions with a large deviation, those satisfying Expressions 19 and 20 are satisfied. Obtainable.

  Control of the distribution in the substrate of the glass substrate 10 can be performed by slightly shifting the position and posture of the crucible serving as the vapor deposition source 100 as described above.

(Other embodiments)
In each of the above embodiments, the case where the light emitting layer is the two layers of the first light emitting layer 40 and the second light emitting layer 50 has been described, but the light emitting layer may be three or more layers.

It is sectional drawing of the organic EL element which concerns on one Embodiment of this invention. It is the figure which showed the compound 1 which is a tertiary amine compound. It is the figure which showed the compound 2 which is an anthracene derivative which has electron transport property. It is the figure which showed the compound 3 which is a yellow light emission additive material. It is the figure which showed the compound 4 which is a blue light emission additive material. It is the figure which showed the table | surface of chromaticity in each examination example. It is the figure which showed the table | surface of the partial regression coefficient. It is the figure which showed direction and distribution of the vapor deposition source with respect to a glass substrate. It is the figure which showed the table | surface of the distribution width and distribution shape with respect to the content rate of a compound. It is the figure which showed the table | surface of the distribution width and distribution shape with respect to the content rate of a compound. It is the figure which showed the table | surface of the distribution width and distribution shape with respect to the content rate of a compound.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Glass substrate 40 1st light emitting layer 50 2nd light emitting layer 30 Hole transport layer 70 Electron transport layer

Claims (4)

It is one of many formed on the substrate (10) and has a plurality of light emitting layers (40, 50) containing a hole transporting material, an electron transporting material, and a dopant, and the plurality of light emitting layers (40 , 50) are organic EL elements that emit different emission colors,
The content of the hole transport material or the electron transport material in one of the light emitting layers (40, 50) is M, the content of the dopant is Md, and the light emitting layers (40, 50) All emission chromaticities are defined as WCIE (x, y),
From the relationship between the content M of the hole transporting material or the electron transporting material, the content Md of the dopant, and the emission chromaticity WCIE (x, y), a correlation function obtained by multiple regression analysis is obtained. Define WCIEx = fx (M, Md), WCIEy = fy (M, Md),
The hole transporting material capable of obtaining a target emission chromaticity when the content M of the hole transporting material or the electron transporting material in the plurality of light emitting layers (40, 50) is a target central value, or The content value of the electron transporting material is defined as M ₀ ,
When the dopant content rate Md in which the target emission chromaticity is obtained when the dopant content rate Md in the plurality of light emitting layers (40, 50) is the target central value is defined as Md ₀ ,
The hole transport material or the electron transport material content M and the dopant content Md in all the light emitting layers (40, 50) are:
_{| Fx (M0, Md 0)} -fx (M, Md) | ≦ 0.005
And,
_{| Fy (M0, Md 0)} -fy (M, Md) | ≦ 0.005
An organic EL element characterized by satisfying   The organic EL device according to claim 1, wherein the plurality of light emitting layers (40, 50) are formed by a co-evaporation method using a plurality of independent evaporation sources. The light emitting layers (40, 50) are sandwiched between a hole transport layer (30) formed of a hole transport material and an electron transport layer (70) formed of an electron transport material,
The hole transporting material contained in the plurality of light emitting layers (40, 50) is the same as the hole transporting material forming the hole transporting layer (30), and the plurality of light emitting layers (40, 50). The organic EL element according to claim 1 or 2, wherein the electron transporting material contained in 50) is the same as the electron transporting material forming the electron transporting layer (70). It is one of many formed on the substrate (10) and has a plurality of light emitting layers (40, 50) containing a hole transporting material, an electron transporting material, and a dopant, and the plurality of light emitting layers (40 , 50) are organic EL elements that emit different emission colors,
The content of the hole transport material or the electron transport material in one of the light emitting layers (40, 50) is M, the content of the dopant is Md, and the light emitting layers (40, 50) All emission chromaticities are defined as WCIE (x, y),
From the relationship between the content M of the hole transporting material or the electron transporting material, the content Md of the dopant, and the emission chromaticity WCIE (x, y), a correlation function obtained by multiple regression analysis is obtained. Define WCIEx = fx (M, Md), WCIEy = fy (M, Md),
The hole transporting material capable of obtaining a target emission chromaticity when the content M of the hole transporting material or the electron transporting material in the plurality of light emitting layers (40, 50) is a target central value, or The content value of the electron transporting material is defined as M ₀ ,
When the dopant content rate Md in which the target emission chromaticity is obtained when the dopant content rate Md in the plurality of light emitting layers (40, 50) is the target central value is defined as Md ₀ ,
When the plurality of light emitting layers (40, 50) are formed on the substrate (10) by a co-evaporation method using independent vapor deposition sources, the hole transport in all of the plurality of light emitting layers (40, 50). In the substrate (10), the content M of the conductive material or the electron transporting material and the content Md of the dopant are
_{| Fx (M0, Md 0)} -fx (M, Md) |> 0.005
Or
_{| Fy (M0, Md 0)} -fy (M, Md) |> 0.005
When the distribution has a distribution satisfying one of the plurality of distributions in the substrate (10) by controlling the combination of the distributions,
_{| Fx (M0, Md 0)} -fx (M, Md) | ≦ 0.005
And,
_{| Fy (M0, Md 0)} -fy (M, Md) | ≦ 0.005
An organic EL element characterized by satisfying

Images