Dimming program, light-emitting device, and lighting device

Abstract

The present invention provides a novel light adjusting program capable of providing a feeling of comfort to humans. Provided is a light adjusting program for acquiring basic data having a 1 / f fluctuation characteristic, generating first smoothed data and second smoothed data by performing moving average processes in respective differing periods for the basic data having the 1 / f fluctuation characteristic, generating light adjusting data by arithmetic processing of the first smoothed data and the second smoothed data, and changing the luminance of a light emitting element on the time-series basis, according to the light adjusting data.

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a light-adjusting program, a light-emitting device, and a lighting device. Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, driving methods thereof, and manufacturing methods thereof. [Background technology]

[0002] Candle and fireplace flames flicker, creating a sense of peace and tranquility. Lighting devices that mimic the flickering of natural light have been developed. For example, Patent Document 1 discloses a lighting device that changes the light output of a light source based on data set by quantifying the brightness of a specific spot on a candle flame. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 9-106891 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional lighting devices that mimic the fluctuations of natural light have the problem of producing unnatural flickering, which can make it difficult to feel at ease. In addition, the use of point light sources has the problem of uneven light emission.

[0005] An object of one embodiment of the present invention is to provide a novel light-adjusting program that can make people feel at ease.Another object of one embodiment of the present invention is to provide a novel light-adjusting program that has a relaxing effect.Another object of one embodiment of the present invention is to provide a novel light-emitting device that can make people feel at ease.Another object of one embodiment of the present invention is to provide a novel light-emitting device that has a relaxing effect.Another object of one embodiment of the present invention is to provide a novel lighting device that can make people feel at ease.Another object of one embodiment of the present invention is to provide a novel lighting device that has a relaxing effect.

[0006] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily need to solve all of these problems. Note that problems other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract other problems from the description in the specification, drawings, claims, etc. [Means for solving the problem]

[0007] One aspect of the present invention is a dimming program that generates first smoothed data and second smoothed data by performing moving average processing with different intervals on basic data having 1 / f fluctuation characteristics, generates dimming data by performing arithmetic processing on the first smoothed data and the second smoothed data, and changes the brightness of a light-emitting device over time in accordance with the dimming data.

[0008] Another aspect of the present invention is a dimming program that generates first smoothed data X and second smoothed data x by performing moving average processing with different intervals on basic data having 1 / f fluctuation characteristics, generates dimming data y by performing arithmetic processing on the first smoothed data X and the second smoothed data x according to the following formula, and changes the luminance of a light-emitting device over time in accordance with the dimming data y.

[0009]

number

[0010] However, in the above formula, y i represents the i-th data of the dimming data y, and X i denotes the i-th data of the first smoothed data X, and x i represents the i-th data of the second smoothed data x, and X max represents the maximum value of X, and min represents the minimum value of X, UL represents a predetermined upper limit value of the X component, LL represents a predetermined lower limit value of the X component, and x max represents the maximum value of x, and min represents the minimum value of x, and A represents a predetermined contribution rate.

[0011] In the light control program having the above configuration, it is preferable that the interval of the moving average process for generating the first smoothed data X is larger than the interval of the moving average process for generating the second smoothed data x.

[0012] Another embodiment of the present invention is a light-emitting device having a light-emitting device and a dimming unit, in which the dimming unit generates first smoothed data and second smoothed data by performing moving average processing with different intervals on basic data having 1 / f fluctuation characteristics, generates dimming data by performing arithmetic processing on the first smoothed data and the second smoothed data, and has a function of changing the luminance of the light-emitting device over time in accordance with the dimming data.

[0013] Another embodiment of the present invention is a light-emitting device including a light-emitting device and a dimming unit. The dimming unit generates first smoothed data X and second smoothed data x by performing moving average processing with different intervals on basic data having 1 / f fluctuation characteristics, and generates dimming data y by performing arithmetic processing on the first smoothed data and the second smoothed data according to the following formula, and changes the luminance of the light-emitting device over time in accordance with the dimming data y.

[0014]

number

[0015] However, in the above formula, y i represents the i-th data of the dimming data y, and X i denotes the i-th data of the first smoothed data X, and x i represents the i-th data of the second smoothed data x, and X max represents the maximum value of X, and min represents the minimum value of X, UL represents a predetermined upper limit value of the X component, LL represents a predetermined lower limit value of the X component, and x max represents the maximum value of x, and min represents the minimum value of x, and A represents a predetermined contribution rate.

[0016] In the light emitting device having the above configuration, it is preferable that the interval of the moving average process for generating the first smoothed data is larger than the interval of the moving average process for generating the second smoothed data.

[0017] In the light-emitting device having each of the above configurations, the light-emitting device preferably has a first electrode, a second electrode, and an EL layer.

[0018] In the light emitting device having each of the above configurations, the emission intensity at 495 nm or less in the electroluminescence spectrum of the light emitting device is preferably 1% or less of the emission intensity at the maximum peak wavelength.

[0019] In the light-emitting devices having the above configurations, the peak wavelength of the electroluminescence spectrum of the light-emitting device is preferably 590 nm or more and 625 nm or less, more preferably 590 nm or more and 620 nm or less, and the maximum peak wavelength is further preferably 590 nm or more and 625 nm or less, more preferably 590 nm or more and 620 nm or less.

[0020] In the light-emitting devices having the above configurations, the half-width of the electroluminescence spectrum of the light-emitting device is preferably 70 nm to 120 nm, more preferably 75 nm to 120 nm, more preferably 80 nm to 120 nm, more preferably 85 nm to 120 nm, and even more preferably 90 nm to 120 nm.

[0021] In the light-emitting devices having the above configurations, it is preferable that the CIE chromaticity (x, y) of the light-emitting device has x of 0.58 or more and 0.63 or less, and y of 0.37 or more and 0.42 or less. More preferably, x is 0.59 or more and 0.63 or less, and y is 0.37 or more and 0.41 or less. Even more preferably, x is 0.59 or more and 0.62 or less, and y is 0.38 or more and 0.41 or less.

[0022] Another embodiment of the present invention is a lighting device including the light-emitting device having any of the above structures and a shade, in which the shade includes a light-transmitting material.

[0023] One embodiment of the present invention includes a light-emitting device having a light-emitting device, and further includes a lighting device having a light-emitting device in its category. Therefore, the light-emitting device in this specification refers to an image display device or a light source (including a lighting device). The light-emitting device also includes a module in which a connector such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) is attached to a light-emitting device, a module in which a printed wiring board is provided at the end of a TCP, or a module in which an IC (Integrated Circuit) is directly mounted on a light-emitting device by a COG (Chip On Glass) method.

[0024] In this specification, the names of the source and drain of a transistor are interchangeable depending on the polarity of the transistor and the level of the potential applied to each terminal. Generally, in an n-channel transistor, the terminal to which a low potential is applied is called the source, and the terminal to which a high potential is applied is called the drain. In a p-channel transistor, the terminal to which a low potential is applied is called the drain, and the terminal to which a high potential is applied is called the source. For convenience, in this specification, the connection relationship of a transistor may be described assuming that the source and drain are fixed, but in reality, the names of the source and drain are interchangeable depending on the above-mentioned potential relationship.

[0025] In this specification, the source of a transistor refers to a source region that is part of a semiconductor film that functions as an active layer, or a source electrode connected to the semiconductor film. Similarly, the drain of a transistor refers to a drain region that is part of the semiconductor film, or a drain electrode connected to the semiconductor film. Furthermore, the gate refers to a gate electrode.

[0026] In this specification, a state in which transistors are connected in series means, for example, a state in which only one of the source or drain of a first transistor is connected to only one of the source or drain of a second transistor, and a state in which transistors are connected in parallel means a state in which one of the source or drain of a first transistor is connected to one of the source or drain of a second transistor, and the other of the source or drain of the first transistor is connected to the other of the source or drain of the second transistor.

[0027] In this specification, "connection" means an electrical connection, and corresponds to a state in which a current, voltage, or potential can be supplied or transmitted. Therefore, a connected state does not necessarily refer to a direct connection, but also includes a state in which a current, voltage, or potential can be supplied or transmitted via a circuit element such as a wiring, resistor, diode, or transistor.

[0028] In this specification, even when components that appear independent on a circuit diagram are connected to each other, in reality, one conductive film may have the functions of multiple components, for example, when part of a wiring functions as an electrode. In this specification, the term "connection" also includes such cases where one conductive film has the functions of multiple components. [Effects of the Invention]

[0029] According to one embodiment of the present invention, a novel light-adjusting program that can make people feel at ease can be provided. According to another embodiment of the present invention, a novel light-adjusting program that has a relaxing effect can be provided. According to another embodiment of the present invention, a novel light-emitting device that can make people feel at ease can be provided. According to another embodiment of the present invention, a novel light-emitting device that has a relaxing effect can be provided. According to another embodiment of the present invention, a novel lighting device that can make people feel at ease can be provided. According to another embodiment of the present invention, a novel lighting device that has a relaxing effect can be provided.

[0030] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract other effects from the description in the specification, drawings, claims, etc. [Brief explanation of the drawings]

[0031] FIG. 1 is a flowchart illustrating a light-adjusting program and a light-emitting device according to one embodiment of the present invention. 2A, 2B, 2C, and 2D are diagrams illustrating data processed by a light emitting device according to one embodiment of the present invention. 3A and 3B illustrate a light-emitting device according to one embodiment of the present invention. 4A and 4B illustrate a lighting device according to one embodiment of the present invention. 5A, 5B, 5C, 5D, and 5E are diagrams illustrating the configuration of a light-emitting device according to an embodiment. 6A and 6B are diagrams illustrating an electronic device according to an embodiment. FIG. 7 is a diagram illustrating an electronic device according to an embodiment. FIG. 8 is a photograph showing the appearance of the light emitting device 1. As shown in FIG. FIG. 9 is a graph of basic data having 1 / f fluctuation characteristics in the light emitting device 1. FIG. 10 is a graph of the first smoothed data and the second smoothed data in the light emitting device 1. In FIG. FIG. 11 is a graph showing the dimming data of the light emitting device 1. As shown in FIG. FIG. 12 is a diagram illustrating the configuration of a light-emitting device according to an example. FIG. 13 is a graph showing the luminance-current density characteristics of light-emitting device 1 and light-emitting device 2. As shown in FIG. FIG. 14 is a graph showing the current efficiency-luminance characteristics of light-emitting device 1 and light-emitting device 2. FIG. 15 is a diagram showing the luminance-voltage characteristics of the light-emitting device 1 and the light-emitting device 2. As shown in FIG. FIG. 16 is a diagram showing the current-voltage characteristics of the light-emitting device 1 and the light-emitting device 2. As shown in FIG. FIG. 17 is a graph showing the external quantum efficiency-luminance characteristics of light-emitting device 1 and light-emitting device 2. As shown in FIG. FIG. 18 is a diagram showing the emission spectra of light-emitting device 1 and light-emitting device 2. As shown in FIG. FIG. 19 is a graph showing the luminance-current density characteristics of the light-emitting device 3. FIG. 20 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 3. FIG. 21 is a graph showing the luminance-voltage characteristics of the light-emitting device 3. As shown in FIG. FIG. 22 is a diagram showing the current-voltage characteristics of the light-emitting device 3. As shown in FIG. FIG. 23 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting device 3. FIG. 24 is a diagram showing the emission spectrum of the light-emitting device 3. As shown in FIG. FIG. 25 is a graph showing the luminance-current density characteristics of the light-emitting device 4. As shown in FIG. FIG. 26 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 4. FIG. 27 is a graph showing the luminance-voltage characteristics of the light-emitting device 4. As shown in FIG. FIG. 28 is a diagram showing the current-voltage characteristics of the light-emitting device 4. As shown in FIG. FIG. 29 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting device 4. FIG. 30 shows the emission spectrum of the light-emitting device 4. As shown in FIG. FIG. 31 is a graph showing the luminance-current density characteristics of light-emitting device 5 and light-emitting device 6. As shown in FIG. FIG. 32 is a graph showing the current efficiency-luminance characteristics of light-emitting device 5 and light-emitting device 6. FIG. 33 is a diagram showing the luminance-voltage characteristics of the light-emitting device 5 and the light-emitting device 6. As shown in FIG. FIG. 34 is a diagram showing the current-voltage characteristics of the light-emitting device 5 and the light-emitting device 6. As shown in FIG. FIG. 35 is a graph showing the external quantum efficiency-luminance characteristics of light-emitting device 5 and light-emitting device 6. As shown in FIG. FIG. 36 shows the emission spectra of light-emitting device 5 and light-emitting device 6. As shown in FIG. FIG. 37 is a graph showing the luminance-current density characteristics of the light-emitting device 7. As shown in FIG. FIG. 38 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 7. As shown in FIG. FIG. 39 is a diagram showing the luminance-voltage characteristics of the light-emitting device 7. As shown in FIG. FIG. 40 is a diagram showing the current-voltage characteristics of the light-emitting device 7. As shown in FIG. FIG. 41 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting device 7. As shown in FIG. FIG. 42 is a diagram showing the emission spectrum of the light-emitting device 7. As shown in FIG. Figure 43 shows the relationship between [Ir(pqn)2(dppm)] 1 1 H NMR chart. Figure 44 shows the absorption and emission spectra of [Ir(pqn)2(dppm)] in dichloromethane solution. DETAILED DESCRIPTION OF THE INVENTION

[0032] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below. In the configuration of the invention described below, the same parts or parts having similar functions will be denoted by the same reference numerals in different drawings, and repeated explanations will be omitted.

[0033] (Embodiment 1) In this embodiment, a light-adjusting program, a light-emitting device, and a lighting device according to one embodiment of the present invention will be described with reference to FIGS.

[0034] FIG. 1 is a flowchart illustrating a method for operating a light-adjusting program and a light-emitting device according to one embodiment of the present invention.

[0035] [Step S1] First, first smoothed data X and second smoothed data x are generated by performing moving average processing with different intervals on basic data f having 1 / f fluctuation characteristics.

[0036] In this specification and the like, 1 / f fluctuation refers to fluctuation in which the distribution of the power spectrum density of data is inversely proportional to the frequency f (f>0).

[0037] The method for acquiring the basic data f having 1 / f fluctuation characteristics is not particularly limited. For example, the basic data having 1 / f fluctuation characteristics may be data generated by quantifying the movement of natural objects, or may be data artificially created using calculation software. Furthermore, data generated and saved in advance may be used, or may be used simultaneously with the generation of the data.

[0038] Examples of data generated by quantifying the movement of natural objects include data generated by using a detection device to quantify wind strength, the brightness of a flame, the movement of waves, etc. Examples of detection devices that can be used include an acceleration sensor, a camera, an illuminance sensor, and a microphone.

[0039] Methods for creating such a system using computational software include cellular automata, intermittent chaos, and half-order integration.

[0040] As the moving average process for generating the first smoothed data X and the second smoothed data x, for example, a simple moving average, a weighted moving average, an exponential moving average, a modified moving average, a triangular moving average, etc. can be used, but the use of a simple moving average is simple and preferable.

[0041] In the case of a simple moving average, the first smoothed data X and the second smoothed data x can be calculated according to the following formulas (1) and (2).

[0042]

number

[0043] However, in the above formulas (1) and (2), f i denotes the i-th data of the basic data f having 1 / f fluctuation characteristics, and X i denotes the i-th data of the first smoothed data X, and x i represents the i-th data of the second smoothed data x. d1 represents the interval (natural number) of the moving average process for generating the first smoothed data, and d2 represents the interval (natural number different from d1) of the moving average process for generating the second smoothed data. In this specification, a natural number represents an integer of 1 or greater.

[0044] In the above formulas (1) and (2), d1 is preferably larger than d2. Specifically, d2 is preferably 5% to 50% of d1, and more preferably 10% to 30% of d1.

[0045] When d1 is made larger than d2, the waveform of the first smoothed data X becomes smoother than the waveform of the second smoothed data x, and long-period components are dominant. In this way, by using two or more pieces of smoothed data (data with different periodic components) that have undergone moving average processing over different intervals to generate light control data in the subsequent step S3, it is possible to generate light control data that has new 1 / f fluctuation characteristics that can make people feel at ease or have a relaxing effect.

[0046] Although an example in which two smoothed data (first smoothed data X and second smoothed data x) are generated from basic data f having 1 / f fluctuation characteristics has been shown here, one aspect of the present invention is not limited to this. In some cases, three or more smoothed data may be generated from basic data f having 1 / f fluctuation characteristics.

[0047] [Step S2] Next, the first smoothed data X and the second smoothed data x are subjected to an arithmetic process to generate dimming data y.

[0048] The calculation process in step S2 can be performed, for example, according to the following equation (3).

[0049]

number

[0050] However, in formula (3), y i represents the i-th data of the dimming data y, and X i indicates the i-th data of the first smoothed data X (hereinafter simply referred to as X), and x i represents the i-th data of the second smoothed data x (hereinafter simply referred to as x).max represents the maximum value of X, and min represents the minimum value of X, UL represents the predetermined upper limit value of the X component (0 or more and 1 or less), and LL represents the predetermined lower limit value of the X component (0 or more and smaller than UL). max represents the maximum value of x, and min represents the minimum value of x. Furthermore, A represents a predetermined contribution rate (0 or more and 1 or less, preferably 0 or more and 0.5 or less). Note that each A may have a different value.

[0051] The calculation process in step S2 can also be performed according to the following formula (4): Formula (4) differs from formula (3) in that one of the multiple As in the formula is changed to A'.

[0052]

number

[0053] However, in formula (4), y i represents the i-th data of the dimming data y, and X i indicates the i-th data of the first smoothed data X (hereinafter simply referred to as X), and x i represents the i-th data of the second smoothed data x (hereinafter simply referred to as x). max represents the maximum value of the first smoothed data X, and X min represents the minimum value of the first smoothed data X, UL represents a predetermined upper limit value (0 or more and 1 or less) of the first smoothed data X component, and LL represents a predetermined lower limit value (0 or more and less than UL) of the first smoothed data X component. max represents the maximum value of the second smoothed data x, and x min represents the minimum value of the second smoothed data x. Furthermore, A represents an arbitrary value between 0 and 1, preferably between 0 and 0.5, and A' represents an arbitrary value between 0 and A.

[0054] The calculation process in step S2 can also be performed according to the following equation (5).

[0055]

number

[0056] However, in formula (5), y i represents the i-th data of the dimming data y, and X i indicates the i-th data of the first smoothed data X (hereinafter simply referred to as X), and x i represents the i-th data of the second smoothed data x (hereinafter simply referred to as x). max represents the maximum value of the first smoothed data X, and X min represents the minimum value of the first smoothed data X. max represents the maximum value of the second smoothed data x, and x min represents the minimum value of the second smoothed data x. Furthermore, A represents an arbitrary value between 0 and 1, preferably between 0 and 0.5. Furthermore, UL represents a predetermined upper limit value of yi (between 0 and 1), and LL represents a predetermined lower limit value of yi (between 0 and 1 and smaller than UL).

[0057] In the above formulas (3) to (5), A and A' determine the contribution rate of the second smoothed data x to the dimming data y. That is, when d1 is larger than d2, in other words, when the first smoothed data X has a waveform that is smoother than the second smoothed data x and has a dominant long-period component, setting A and A' larger increases the short-period component of the fluctuation of the dimming data y, and setting A and A' smaller decreases the short-period component of the fluctuation of the dimming data.

[0058] By generating the dimming data y as described above, the dimming data y can be optimized, and dimming data with new 1 / f fluctuation characteristics can be generated that can make people feel at ease or have a relaxing effect.

[0059] Although an example in which the dimming data y is generated by arithmetic processing of two pieces of smoothed data (first smoothed data X and second smoothed data x) has been described above, one aspect of the present invention is not limited to this. In some cases, dimming data may be generated by arithmetic processing of three or more pieces of smoothed data.

[0060] [Step S3] Next, the luminance of the light-emitting device is changed in a time series manner in accordance with the dimming data y.

[0061] The light-emitting device used in the light-adjusting program and the light-emitting device of one embodiment of the present invention is not particularly limited. For example, a light-emitting device such as a fluorescent lamp, an incandescent lamp, an LED, or an organic EL element can be used in the light-adjusting program and the light-emitting device of one embodiment of the present invention.

[0062] The method for changing the brightness of the light-emitting device according to the dimming data can be selected appropriately depending on the light-emitting device used, such as phase control dimming, current amplitude dimming, or PWM (Pulse Width Modulation) control.

[0063] In the case of the phase control method, the brightness of the light-emitting device is controlled by directly adjusting the power to the light-emitting device. Since dimming control can be performed using only the power line, only two wires are required between the dimming unit and the light-emitting device, which simplifies the manufacturing of the light-emitting device.

[0064] With the PWM control method, the brightness of the light-emitting device is controlled by changing the time ratio (duty ratio) between on and off. In addition to two power lines, two signal lines are required as wiring, but compared to the phase control method, it is less susceptible to power supply fluctuations and therefore allows for stable dimming. Furthermore, compared to current amplitude dimming, with the PWM control method, the current flowing through the light-emitting device is constant, so the emitted color can also be kept constant. The PWM control method can ensure a wider dynamic range.

[0065] Furthermore, in the case of PWM control, flickering of the light emitted by the light-emitting device can be suppressed by setting a higher frequency. For example, setting the frequency to approximately 100 Hz or higher can suppress flickering of the light emitted by the light-emitting device.

[0066] Generally, when brightness is changed over time using a PWM control method, flickering may occur in the light emitted from a light-emitting device, but by using the dimming program of one embodiment of the present invention, flickering can be suppressed, and therefore brightness can be changed more naturally.

[0067] Alternatively, new dimming data Y may be generated using the dimming data y generated in step S2 according to Equation (6), and the luminance of the light-emitting device may be changed in a time series manner according to the dimming data Y.

[0068]

number

[0069] In the formula (6), a and b each independently represent an arbitrary value.

[0070] With the above-described configuration, it is possible to provide a light control program and a light emitting device that can make people feel at ease or that has a relaxing effect.

[0071] FIG. 2 shows a diagram illustrating data acquired or generated by a light-adjusting program and a light-emitting device according to one embodiment of the present invention. The vertical axis represents the intensity of each data, and the horizontal axis represents the data number. FIG. 2A shows an example of basic data f having 1 / f fluctuation characteristics acquired by the light-adjusting program and a light-emitting device. FIG. 2B shows an example of first smoothed data X generated by the light-adjusting program and a light-emitting device. FIG. 2C shows an example of second smoothed data x generated by the light-adjusting program and a light-emitting device. FIG. 2D shows an example of light-adjusting data y generated by the light-adjusting program and a light-emitting device.

[0072] As shown in Figures 2A, 2B, and 2C, the first smoothed data X (Figure 2B) and the second smoothed data x (Figure 2C) are smoothed more than the basic data f (Figure 2A). Also, as shown in Figures 2B and 2C, the first smoothed data X (Figure 2B) is smoothed more than the second smoothed data x (Figure 2C).

[0073] The light control program and light emitting device according to one embodiment of the present invention can generate the light control data y shown in FIG. 2D by combining the two types of smoothed data in this way.

[0074] 3A is a block diagram illustrating a light-emitting device 300 according to one embodiment of the present invention. As shown in FIG. 3A, the light-emitting device 300 includes at least a power source 301, a light control unit 302, and a light-emitting device 303.

[0075] The light control unit 302 has a function of changing the luminance of the light emitting device 303 in a time series manner in accordance with the light control data y generated in steps S1 to S3 described above.

[0076] The light control unit 302 includes, for example, a storage unit. The storage unit can be loaded with the light control program according to one embodiment of the present invention. Alternatively, the storage unit can store pre-generated light control data y.

[0077] 3B illustrates a lighting device 310 according to one embodiment of the present invention. As shown in FIG. 3B, the lighting device 310 includes a shade 311, a light-emitting device 300, a base 312, and an operation button 313. The light-emitting device 300 is covered with the shade 311.

[0078] The shade 311 is made of a light-transmitting material. The light emitted by the light-emitting device 300 is scattered by the shade 311, so that the light emitted by the lighting device 310 can be made softer, thereby enhancing the relaxing effect.

[0079] Examples of the translucent material that can be used for the shade 311 include transparent resin material, milky white resin material, resin material mixed with a diffusing material, glass, paper, cloth, wood, thinly processed metal, and ceramics. However, the materials that can be used for the shade 311 are not limited to these. Any material that has translucency and can be molded into a shape that covers the light emitting device 300 can be used for the shade 311.

[0080] In this specification, the term "shade" can be interchangeably referred to as "casing" or "cover" depending on the situation. In addition, in this specification, the term "translucent" refers to the property of transmitting at least light in the wavelength range of visible light (light with a wavelength of 400 nm or more and 750 nm or less).

[0081] Fig. 4A shows illumination device 310A, which is a modified example of illumination device 310. As shown in Fig. 4A, illumination device 310A has a cylindrical shade 311. In illumination device 310A, shade 311 is made of a transparent resin material, and light emitted from light-emitting device 300 passes through shade 311 while being totally reflected, and is emitted as light 320 above illumination device 310A. With this configuration, the direction in which light is emitted can be controlled.

[0082] 4B shows illumination device 310B, which is a modification of illumination device 310A. Illumination device 310B has cylindrical shade 311a made of a transparent resin material, and further has shade 311b that covers both shade 311a and light-emitting device 300. In illumination device 310B, light emitted from light-emitting device 300 passes through shade 311a while being totally reflected, and emits light 320 above 311a. Furthermore, light 320 passes through shade 311b and emits light 321. With this configuration, the direction of light emission can be controlled, resulting in an illumination device that emits softer light.

[0083] Furthermore, the lighting device of one embodiment of the present invention can be operated not only by the operation button 313 of the base 312 but also by a remote controller. FIG.

[0084] The remote controller 330 may include multiple buttons that allow the user to select a fluctuation mode in addition to turning the lighting device 310B on and off. Specific examples of fluctuation modes include a sine wave and fluctuations that can be generated by a dimming program according to an embodiment of the present invention. A non-fluctuation light emission mode may also be selected. By using different variables for multiple dimming programs according to an embodiment of the present invention, the user may be able to select a preferred one from multiple 1 / f fluctuations that vary the fluctuation.

[0085] Furthermore, it is preferable to use a light-emitting device (organic EL element) having a first electrode, a second electrode, and an EL layer as light-emitting device 303. Such a light-emitting device has surface emission, and therefore, compared to a light-emitting device having point emission, the light emitted by light-emitting device 300 can be made uniform and soft. This can enhance the relaxing effect of light-emitting device 300. An example of a light-emitting device having a first electrode, a second electrode, and an EL layer that can be used in light-emitting device 300 will be described in detail in embodiment 2.

[0086] When a light-emitting device having a first electrode, a second electrode, and an EL layer is used as the light-emitting device 303, the half-width of the electroluminescence spectrum of the light-emitting device is preferably 70 nm or more, and more preferably 75 nm or more. This improves the color rendering of the light-emitting device 300 and enables light emission closer to natural light. Furthermore, the half-width of the electroluminescence spectrum of the light-emitting device is preferably 120 nm or less. This enables light emission with reduced blue light, as described below. Therefore, the half-width of the electroluminescence spectrum of the light-emitting device is preferably 70 nm or more and 120 nm or less. It is more preferably 75 nm or more and 120 nm or less, more preferably 80 nm or more and 120 nm or less, more preferably 85 nm or more and 120 nm or less, and even more preferably 90 nm or more and 120 nm or less.

[0087] Furthermore, when a light-emitting device having a first electrode, a second electrode, and an EL layer is used as the light-emitting device 303, the peak wavelength of the electroluminescence spectrum of the light-emitting device is preferably 590 nm or more and 625 nm or less, more preferably 590 nm or more and 620 nm or less. This allows for a light-emitting device that emits warm-colored light that is closer to natural light such as sunsets, bonfires, and candlelight, as well as the light of incandescent bulbs. The warm-colored light emitted by sunsets, bonfires, candle flames, and incandescent bulbs stimulates the human parasympathetic nervous system and provides a relaxing effect. Therefore, by using a light-emitting device whose electroluminescence spectrum has a peak wavelength of 590 nm or more and 625 nm or less (more preferably 590 nm or more and 620 nm or less), a light-emitting device that provides a relaxing effect to the user can be obtained.

[0088] It is particularly effective for the maximum peak wavelength of the electroluminescence spectrum of the light-emitting device to be within the above-mentioned range. That is, when a light-emitting device having a first electrode, a second electrode, and an EL layer is used as the light-emitting device 303, the maximum peak wavelength of the electroluminescence spectrum of the light-emitting device is preferably 590 nm or more and 625 nm or less, more preferably 590 nm or more and 620 nm or less. This not only enables a light-emitting device to emit warm-colored light very similar to natural light such as sunsets, bonfires, and candlelight, as well as light from incandescent bulbs, but also prevents the emission color from deviating from the warm color due to process variations, resulting in an inexpensive light-emitting device suitable for mass production. Furthermore, the warm-colored light emitted by sunsets, bonfires, candle flames, and incandescent bulbs stimulates the human parasympathetic nervous system, resulting in a relaxing effect. Therefore, using a light-emitting device whose maximum peak wavelength of the electroluminescence spectrum is 590 nm or more and 625 nm or less (more preferably 590 nm or more and 620 nm or less) can provide a light-emitting device that provides a significant relaxing effect to the user.

[0089] Furthermore, when a light-emitting device having a first electrode, a second electrode, and an EL layer is used as the light-emitting device 303, it is more preferable that the electroluminescence spectrum of the light-emitting device contains almost no blue light. Specifically, it is more preferable that the emission intensity of the visible light component of 495 nm or less in the electroluminescence spectrum is 1 / 100 or less of the emission intensity at the maximum peak wavelength.

[0090] Blue light refers to blue light (wavelength 360-495nm) that has high energy among visible light. Blue light reaches the retina without being absorbed by the membranes or lens, and is said to cause damage to the retina and optic nerve. Exposure to blue light at night can also disrupt the circadian rhythm. The danger of blue light is that the human eye has low visual sensitivity to light in that wavelength range. Therefore, even if people are exposed to strong blue light, they are unaware of it, and damage can easily accumulate.

[0091] Therefore, by using a light-emitting device whose electroluminescence spectrum contains almost no blue light, it is possible to provide a light-emitting device that can reduce eye fatigue and improve the quality of sleep of the user. From this perspective, in order to reduce the blue light component, the half-width of the electroluminescence spectrum of the light-emitting device is preferably 120 nm or less.

[0092] The light-emitting device 300 having the above-described light-emitting device configuration can be used as a light-emitting device for light therapy (phototherapy) that exhibits a relaxation effect and improves sleep quality. That is, another embodiment of the present invention is a light-emitting device for phototherapy, in which the peak wavelength (or maximum peak wavelength) of the electroluminescence spectrum is 590 nm to 625 nm (more preferably 590 nm to 620 nm), the half-width of the electroluminescence spectrum is 70 nm to 120 nm (more preferably 75 nm to 120 nm), and the emission intensity of visible light components of 495 nm or less is 1 / 100 or less of the emission intensity at the maximum peak wavelength of the electroluminescence spectrum. The half-width is more preferably in the range of 80 nm to 120 nm, more preferably 85 nm to 120 nm, and even more preferably 90 nm to 120 nm.

[0093] In the light-emitting device according to one embodiment of the present invention, the warm-colored light emitted from the device, which stimulates the parasympathetic nervous system and provides a relaxing effect, preferably falls within a specific range of emitted colors. That is, in the light-emitting device, the CIE chromaticity (x, y) of the device is preferably such that x is 0.58 or more and 0.63 or less, and y is 0.37 or more and 0.42 or less. More preferably, x is 0.59 or more and 0.63 or less, and y is 0.37 or more and 0.41 or less. Even more preferably, x is 0.59 or more and 0.62 or less, and y is 0.38 or more and 0.41 or less.

[0094] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0095] (Embodiment 2) In this embodiment, a light-emitting device that can be used for a light-emitting device of one embodiment of the present invention will be described with reference to FIGS. 5A to 5E.

[0096] <Basic structure of light-emitting devices> The basic structure of a light-emitting device will be described. Fig. 5A shows a light-emitting device having an EL layer including a light-emitting layer between a pair of electrodes. Specifically, the device has a structure in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102.

[0097] Figure 5B also shows a light-emitting device with a stacked structure (tandem structure) having multiple (two in Figure 5B) EL layers (103a, 103b) between a pair of electrodes and a charge generation layer 106 between the EL layers.

[0098] The charge generation layer 106 has the function of injecting electrons into one EL layer (103a or 103b) and injecting holes into the other EL layer (103b or 103a) when a potential difference is generated between the first electrode 101 and the second electrode 102. Therefore, in Fig. 5B, when a voltage is applied to the first electrode 101 so that the potential is higher than that of the second electrode 102, electrons are injected from the charge generation layer 106 into the EL layer 103a and holes are injected into the EL layer 103b.

[0099] From the viewpoint of light extraction efficiency, the charge generation layer 106 is preferably transparent to visible light (specifically, the visible light transmittance of the charge generation layer 106 is 40% or more). The charge generation layer 106 functions even if it has lower conductivity than the first electrode 101 and the second electrode 102.

[0100] FIG. 5C also shows a stacked structure of the EL layer 103 of the light-emitting device according to one embodiment of the present invention. In this case, the first electrode 101 functions as an anode, and the second electrode 102 functions as a cathode. The EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are sequentially stacked on the first electrode 101. The light-emitting layer 113 may have a structure in which a plurality of light-emitting layers emitting different light colors are stacked. For example, a light-emitting layer containing a light-emitting substance that emits red light and a light-emitting layer containing a light-emitting substance that emits green light are stacked, or a layer containing a carrier-transporting material is stacked between the light-emitting layers. However, the stacked structure of the light-emitting layer 113 is not limited to the above. For example, the light-emitting layer 113 may have a structure in which a plurality of light-emitting layers emitting the same light color are stacked. For example, a first light-emitting layer containing a red-emitting material and a second light-emitting layer containing a red-emitting material may be stacked together, or may be stacked with a layer containing a carrier transport material interposed therebetween. A structure in which multiple light-emitting layers emitting the same light color are stacked may provide higher reliability than a single-layer structure. Even in a tandem structure such as that shown in FIG. 5B , in which multiple EL layers are included, each EL layer is stacked sequentially from the anode side as described above. Furthermore, when the first electrode 101 is the cathode and the second electrode 102 is the anode, the stacking order of the EL layer 103 is reversed. Specifically, the structure is such that 111 on the first electrode 101, which is the cathode, is an electron injection layer, 112 is an electron transport layer, 113 is a light-emitting layer, 114 is a hole transport layer, and 115 is a hole injection layer.

[0101] The light-emitting layers 113 included in the EL layers (103, 103a, 103b) each contain a combination of multiple substances, such as light-emitting substances, and can be configured to emit fluorescent or phosphorescent light of a desired emission color. The light-emitting layer 113 may also have a stacked structure in which light-emitting layers with different emission colors are stacked. In this case, the light-emitting substance and / or other substances used in each stacked light-emitting layer may be different materials. The multiple EL layers (103a, 103b) shown in FIG. 5B may also be configured to emit different emission colors. In this case, the light-emitting substance and / or other substances used in each light-emitting layer may be different materials. The light-emitting layer 113 may also have a stacked structure in which light-emitting layers with the same emission color are stacked. In this case, the light-emitting substance and / or other substances used in each stacked light-emitting layer may be different or the same. The multiple EL layers (103a, 103b) shown in FIG. 5B may also be configured to emit the same emission color. In this case, the luminescent material and other materials used in each luminescent layer may be different from each other or the same.

[0102] Furthermore, in a light-emitting device according to one embodiment of the present invention, for example, by configuring the first electrode 101 shown in FIG. 5C as a reflective electrode and the second electrode 102 as a semi-transmissive and semi-reflective electrode to form a micro-optical resonator (microcavity) structure, the light emitted from the light-emitting layer 113 included in the EL layer 103 can be resonated between the two electrodes, thereby enhancing the light emitted from the second electrode 102.

[0103] When the first electrode 101 of the light-emitting device is a reflective electrode having a laminated structure of a reflective conductive material and a light-transmitting conductive material (transparent conductive film), optical adjustment can be performed by controlling the film thickness of the transparent conductive film. Specifically, it is preferable to adjust the optical distance (product of film thickness and refractive index) between the first electrode 101 and the second electrode 102 to mλ / 2 (where m is a natural number) or close to it, for the wavelength λ of light obtained from the light-emitting layer 113.

[0104] In order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, it is preferable to adjust the optical distance from the first electrode 101 to the region (light-emitting region) in the light-emitting layer 113 where the desired light is obtained and the optical distance from the second electrode 102 to the region (light-emitting region) in the light-emitting layer 113 where the desired light is obtained to be (2m'+1)λ / 4 (where m' is a natural number) or close to that. Note that the light-emitting region here refers to the recombination region of holes and electrons in the light-emitting layer 113.

[0105] By performing such optical adjustment, the spectrum of the specific monochromatic light obtained from the light-emitting layer 113 can be narrowed, and light emission with good color purity can be obtained.

[0106] In the above case, the optical distance between the first electrode 101 and the second electrode 102 can be strictly defined as the total thickness from the reflective region of the first electrode 101 to the reflective region of the second electrode 102. However, since it is difficult to precisely determine the reflective regions of the first electrode 101 and the second electrode 102, the above-mentioned effect can be sufficiently achieved by assuming any position of the first electrode 101 and the second electrode 102 as the reflective region. Furthermore, the optical distance between the first electrode 101 and the light-emitting layer from which desired light is obtained can be strictly defined as the optical distance between the reflective region of the first electrode 101 and the light-emitting region of the light-emitting layer from which desired light is obtained. However, since it is difficult to precisely determine the reflective region of the first electrode 101 and the light-emitting region of the light-emitting layer from which desired light is obtained, the above-mentioned effect can be sufficiently achieved by assuming any position of the first electrode 101 as the reflective region and any position of the light-emitting layer from which desired light is obtained as the light-emitting region.

[0107] The light-emitting device shown in FIG. 5D is an example of the tandem-structure light-emitting device shown in FIG. 5B, and as shown in the figure, has a structure in which two EL layers (103a, 103b) are stacked with a charge generation layer 106 sandwiched between them. The two EL layers (103a, 103b) each have a light-emitting layer (113a, 113b), and the light-emitting colors of the light-emitting layers can be freely combined. For example, the light-emitting layer 113a can be red, and the light-emitting layer 113b can be red, green, or yellow.

[0108] The light-emitting device shown in FIG. 5E is an example of the tandem-structure light-emitting device shown in FIG. 5B, and as shown in the figure, has a structure in which three EL layers (103a, 103b, 103c) are stacked with charge generation layers (106a, 106b) sandwiched between them. Each of the three EL layers (103a, 103b, 103c) has a light-emitting layer (113a, 113b, 113c), and the light-emitting colors of the light-emitting layers can be freely combined. For example, light-emitting layer 113a can be red, light-emitting layer 113b can be red, green, or yellow, and light-emitting layer 113c can be red.

[0109] In the light-emitting device according to one embodiment of the present invention, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (such as a transparent electrode or a semi-transmitting / semi-reflective electrode). When the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. In addition, when the semi-transmitting / semi-reflective electrode is used, the visible light reflectance of the semi-transmitting / semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Furthermore, these electrodes have a resistivity of 1×10 -2 It is preferable to set it to Ωcm or less.

[0110] In the above-described light-emitting device according to one embodiment of the present invention, when one of the first electrode 101 and the second electrode 102 is a reflective electrode (a reflective electrode), the reflectivity of the reflective electrode for visible light is set to 40% to 100%, preferably 70% to 100%. -2 It is preferable to set it to Ωcm or less.

[0111] <Specific structure of the light-emitting device> Next, a specific structure of a light-emitting device according to one embodiment of the present invention will be described. Here, the description will be made using FIG. 5D, which has a tandem structure. The same EL layer structure applies to the single-structure light-emitting devices shown in FIGS. 5A and 5C. When the light-emitting device shown in FIG. 5D has a microcavity structure, the first electrode 101 is formed as a reflective electrode, and the second electrode 102 is formed as a semi-transmissive and semi-reflective electrode. Therefore, a single or multiple desired electrode materials can be used to form a single layer or a stacked layer. The second electrode 102 is formed by selecting a material in the same manner as described above after the EL layer 103b is formed.

[0112] <First Electrode and Second Electrode> The materials forming the first electrode 101 and the second electrode 102 can be any combination of the following materials, as long as they fulfill the functions of both electrodes described above. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Specific examples include In-Sn oxide (also known as ITO), In-Si-Sn oxide (also known as ITSO), In-Zn oxide, and In-W-Zn oxide. Other metals that can be used include aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), as well as alloys containing any combination of these metals. Other examples that can be used include elements belonging to Group 1 or 2 of the periodic table (e.g., lithium (Li), cesium (Cs), calcium (Ca), and strontium (Sr)), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing appropriate combinations of these elements, as well as graphene.

[0113] 5D, when the first electrode 101 is an anode, the hole injection layer 111a and the hole transport layer 112a of the EL layer 103a are sequentially formed by vacuum deposition on the first electrode 101. After the EL layer 103a and the charge generation layer 106 are formed, the hole injection layer 111b and the hole transport layer 112b of the EL layer 103b are similarly sequentially formed on the charge generation layer 106.

[0114] <Hole injection layer> The hole injection layer (111, 111a, 111b) is a layer that injects holes from the first electrode 101, which is an anode, or the charge generation layer (106, 106a, 106b) to the EL layer (103, 103a, 103b), and is a layer that contains an organic acceptor material or a material with high hole injection properties.

[0115] An organic acceptor material is a material that can generate holes in an organic compound by causing charge separation between the organic compound and another organic compound whose LUMO (Lowest Unoccupied Molecular Orbital) level and HOMO (Highest Occupied Molecular Orbital) level are close to each other. Therefore, compounds having electron-withdrawing groups (e.g., halogen groups, cyano groups), such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives, can be used as organic acceptor materials. For example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, and the like can be used. Among organic acceptor materials, compounds such as HAT-CN, in which an electron-withdrawing group is bonded to a fused aromatic ring containing multiple heteroatoms, are particularly suitable because of their high acceptability and thermal stability. Radialene derivatives containing electron-withdrawing groups (especially halogen groups such as fluoro groups, cyano groups, etc.) are also preferred because of their extremely high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropanetriylidenetris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenetris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenetris[2,3,4,5,6-pentafluorobenzeneacetonitrile].

[0116] In addition, as a material with high hole injection properties, oxides of metals belonging to Groups 4 to 8 of the periodic table (e.g., transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide) can be used. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is preferred because it is stable in the air, has low hygroscopicity, and is easy to handle. Other examples include phthalocyanine-based compounds such as phthalocyanine (abbreviated as HPc) and copper phthalocyanine (abbreviated as CuPc).

[0117] In addition to the above materials, we also have low molecular weight compounds such as 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), and 1,3,5- Aromatic amine compounds such as tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) can be used.

[0118] In addition, polymeric compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can be used. Alternatively, polymeric compounds containing added acids, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviation: PEDOT / PSS) and polyaniline / poly(styrenesulfonic acid) (PAni / PSS), can also be used.

[0119] Furthermore, a mixed material containing a hole transport material and the above-mentioned organic acceptor material (electron accepting material) can also be used as the material with high hole injection properties. In this case, electrons are extracted from the hole transport material by the organic acceptor material, generating holes in the hole injection layer 111, and the holes are injected into the light-emitting layer 113 via the hole transport layer 112. Note that the hole injection layer 111 may be formed as a single layer made of a mixed material containing the hole transport material and the organic acceptor material (electron accepting material), or may be formed by laminating the hole transport material and the organic acceptor material (electron accepting material) as separate layers.

[0120] As for hole transporting materials, the hole mobility at a square root of the electric field strength [V / cm] of 600 is 1×10 -6 cm 2 A substance having a hole mobility of 1 / Vs or more is preferred. Note that other substances can be used as long as they have a higher hole transporting property than an electron transporting property.

[0121] As the hole transporting material, a material with high hole transporting properties, such as a compound having a π-electron-rich heteroaromatic ring (for example, a carbazole derivative, a furan derivative, or a thiophene derivative) or an aromatic amine (an organic compound having an aromatic amine skeleton), is preferred.

[0122] Examples of the carbazole derivatives (organic compounds having a carbazole ring) include bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives), aromatic amines having a carbazolyl group, and the like.

[0123] Specific examples of the bicarbazole derivatives (e.g., 3,3′-bicarbazole derivatives) include 3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9′-bis(biphenyl-4-yl)-3,3′-bi-9H-carbazole (abbreviation: BisBPCz), 9,9′-bis(1,1′-biphenyl-3-yl)-3,3′-bi-9H-carbazole (abbreviation: BismBPCz), 9-(1,1′-biphenyl-3-yl)-9′-(1,1′-biphenyl-4-yl)-9H,9′H-3,3′-bicarbazole (abbreviation: mBPCCBP), and 9-(2-naphthyl)-9′-phenyl-9H,9′H-3,3′-bicarbazole (abbreviation: βNCCP).

[0124] Specific examples of the aromatic amine having a carbazolyl group include 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)]- 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), ,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1 -naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), etc.

[0125] In addition to the above, examples of the carbazole derivatives include 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA).

[0126] Specific examples of the furan derivatives (organic compounds having a furan ring) include 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II).

[0127] Specific examples of the thiophene derivatives (organic compounds having a thiophene ring) include organic compounds having a thiophene ring, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV).

[0128] Specific examples of the aromatic amine include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP ...,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4,4'-bis[N-(spi -phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), N-(4-biphenyl)-N-{4-[(9-phenyl)-9H-fluoren-9-yl]-phenyl}-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as FBiFLP), N,N,N',N'-tetrakis(4-biphenyl)-1,1-biphenyl-4,4'-diamine (abbreviated as BBA2BP), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9'-bifluorene (abbreviation: DPA2SF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: m-MTDATA), N,N'-di(p-tolyl)-N,N'-Diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), DNTPD, 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4) ), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-Diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4- Biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviated as TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviated as αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviated as YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]triphenylamine Bis(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazol-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: YGTBiβNB), bis-biphenyl-4'-(carbazol-9-yl)biphenylamine (abbreviation: YGBBi1BP), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), N,N-bis(9,9-dimethyl-9H-fluorene-2- N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, and the like are mentioned.

[0129] Other examples of hole-transporting materials that can be used include polymeric compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD). Alternatively, polymeric compounds containing added acids, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviation: PEDOT / PSS) and polyaniline / poly(styrenesulfonic acid) (PAni / PSS), can also be used.

[0130] However, the hole transporting material is not limited to the above, and one or more of various known materials may be used as the hole transporting material.

[0131] The hole injection layers (111, 111a, 111b) can be formed using various known film formation methods, for example, vacuum deposition.

[0132] <Hole transport layer> The hole transport layers (112, 112a, 112b) are layers that transport holes injected from the first electrode 101 by the hole injection layers (111, 111a, 111b) to the light-emitting layers (113, 113a, 113b). The hole transport layers (112, 112a, 112b) are layers that contain a hole transport material. Therefore, the hole transport layers (112, 112a, 112b) can use the same hole transport material that can be used for the hole injection layers (111, 111a, 111b).

[0133] In the light-emitting device of one embodiment of the present invention, the light-emitting layers (113, 113a, 113b) can be formed using the same organic compound as that used in the hole-transport layers (112, 112a, 112b). It is more preferable to use the same organic compound in the hole-transport layers (112, 112a, 112b) and the light-emitting layers (113, 113a, 113b) because holes can be efficiently transported from the hole-transport layers (112, 112a, 112b) to the light-emitting layers (113, 113a, 113b).

[0134] <Light-emitting layer> The light-emitting layers (113, 113a, 113b) are layers containing a light-emitting substance. Note that, as the light-emitting substance that can be used for the light-emitting layers (113, 113a, 113b), a substance that emits light of a color such as green, yellow-green, yellow, orange, or red can be appropriately used. Furthermore, when there are multiple light-emitting layers, a structure can be achieved in which different light-emitting substances are used for each light-emitting layer, thereby emitting different light colors. Furthermore, a stacked structure in which one light-emitting layer contains different light-emitting substances can be used.

[0135] Furthermore, the light-emitting layers (113, 113a, 113b) may contain one or more organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material).

[0136] When multiple host materials are used in the light-emitting layers (113, 113a, and 113b), it is preferable to use a substance having a larger energy gap as the second host material than the energy gaps of the existing guest material and the first host material. Furthermore, it is preferable that the lowest singlet excitation energy level (S1 level) of the second host material 3 is higher than the S1 level of the first host material, and the lowest triplet excitation energy level (T1 level) of the second host material is higher than the T1 level of the guest material. Furthermore, it is preferable that the lowest triplet excitation energy level (T1 level) of the second host material is higher than the T1 level of the first host material. This structure allows the formation of an exciplex using two types of host materials. To efficiently form an exciplex, it is particularly preferable to combine a compound that easily accepts holes (hole-transporting material) with a compound that easily accepts electrons (electron-transporting material). This structure also allows the simultaneous realization of high efficiency, low voltage, and long life.

[0137] The organic compounds used as the host materials (including the first host material and the second host material) may be hole-transporting materials usable in the hole-transporting layers (112, 112a, and 112b) described above or electron-transporting materials usable in the electron-transporting layers (114, 114a, and 114b) described below, as long as they satisfy the requirements for a host material used in an emitting layer. These organic compounds may also be exciplexes composed of multiple organic compounds (the first host material and the second host material described above). An exciplex (also referred to as an exciplex) formed by multiple organic compounds in an excited state has an extremely small difference between the S1 and T1 levels and functions as a TADF material capable of converting triplet excitation energy into singlet excitation energy. A combination of multiple organic compounds that form an exciplex is preferably one in which one of the compounds has a π-electron-deficient heteroaromatic ring and the other has a π-electron-rich heteroaromatic ring. As a combination for forming an exciplex, one of the compounds may be a phosphorescent material such as an iridium, rhodium, or platinum-based organometallic complex or a metal complex.

[0138] There are no particular limitations on the light-emitting substance that can be used in the light-emitting layer (113, 113a, 113b), and light-emitting substances that convert singlet excitation energy into light emission in the visible light range, or light-emitting substances that convert triplet excitation energy into light emission in the visible light range, can be used.

[0139] <Light-emitting material that converts singlet excitation energy into light> Examples of luminescent materials that convert singlet excitation energy into luminescence and can be used in the luminescent layers (113, 113a, 113b) include the following fluorescent substances (fluorescent luminescent materials): pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives. Pyrene derivatives are particularly preferred because of their high luminescence quantum yield. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), (N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine) (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophen-2-yl)-N , N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), and the like.

[0140] In addition, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)phenyl N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'- (9-Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenyl) N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), and the like can be used.

[0141] In addition, N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl- 2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone, (abbreviation: DPQd), rubrene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yl N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhTD), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB),6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), 1,6BnfAP Examples of suitable compounds include rn-03, 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10FrA2Nbf(IV)-02). Pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 can be used. Among the compounds mentioned above, propanedinitrile compounds are particularly suitable for obtaining electroluminescence with a peak wavelength of 590 nm to 620 nm.

[0142] <Light-emitting material that converts triplet excitation energy into light> Next, examples of luminescent materials that convert triplet excitation energy into luminescence and can be used in the luminescent layer 113 include phosphorescent materials and thermally activated delayed fluorescence (TADF) materials that exhibit thermally activated delayed fluorescence.

[0143] A phosphorescent material is a compound that exhibits phosphorescence but does not exhibit fluorescence at a temperature range from low temperatures (e.g., 77 K) to room temperature (i.e., 77 K to 313 K). The phosphorescent material preferably contains a metal element with a large spin-orbit interaction, such as an organometallic complex, a metal complex (platinum complex), or a rare-earth metal complex. Specifically, a transition metal element is preferred, and a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)) is particularly preferred. Among these, iridium is preferred because it can increase the transition probability associated with the direct transition between the singlet ground state and the triplet excited state.

[0144] <Phosphorescent material (495nm to 590nm: green or yellow)> Examples of phosphorescent materials that exhibit green or yellow color and have an emission spectrum with a peak wavelength of 495 nm or more and 590 nm or less include the following materials.

[0145] For example, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm )2(acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp)2(acac)]), and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]). iridium complexes, organometallic iridium complexes containing a pyrazine ring such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(4dppy)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl -κN)phenyl-κC], [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), [2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofuro Iridium(III) (abbreviated as Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC] Organometallic iridium complexes containing a pyridine ring, such as [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mdppy)), and bis(2,4-diphenyl-1,3-oxazolato-N,C 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(dpo)2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridinato-N,C 2’}Iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph)2(acac)]), bis(2-phenylbenzothiazolato-N,C 2’ ) iridium(III) acetylacetonate (abbreviated as [Ir(bt)2(acac)]), as well as rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]).

[0146] <Phosphorescent materials (570nm to 750nm: yellow or red)> Examples of phosphorescent materials that exhibit yellow or red color and have an emission spectrum with a peak wavelength of 570 nm or more and 750 nm or less include the following materials.

[0147] For example, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), (dipivaloylmethanato)bis[4,6-di(naphthalen-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), bis[2-(2-quinolinyl-κN)phenyl-κC][2-(6-phenyl-4-pyrimidinyl-κN] 3Organometallic complexes containing a pyrimidine ring, such as [Ir(pqn)2(dppm)], (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κN). 2 O,O')iridium(III) (abbreviation: [Ir(dmdppr-P)2(dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ) 2 O,O')iridium(III) (abbreviation: [Ir(dmdppr-dmCP)2(dpm)]), bis[2-(5-(2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN)-4,6-dimethylphenyl-κC](2,2',6,6'-tetramethyl-3,5-heptanedionato-κO,O')iridium(III) (abbreviation: [Ir(dmdppr-dmp)2(dpm)]), (acetylacetonato)bis[2-methyl-3-phenylquinoxalinato-N,C 2’ ]iridium(III) (abbreviation: [Ir(mpq)2(acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C 2’ )iridium(III) (abbreviation: [Ir(dpq)2(acac)]), organometallic complexes with a pyrazine ring such as (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), bis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC](2,4-pentanedionato-κ 2 Examples of such complexes include organometallic complexes with a pyridine ring, such as (O,O')iridium(III) (abbreviation: [Ir(dmpqn)2(acac)]), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(II) (abbreviation: [PtOEP]), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]). Among the above, organometallic complexes having either a pyrimidine ring or a pyrazine ring, or both, are suitable for obtaining electroluminescence having a peak wavelength of 590 nm to 620 nm. Furthermore, among organometallic complexes having a pyridine ring, organometallic complexes having a quinoline ring are particularly suitable for obtaining electroluminescence having a peak wavelength of 590 nm to 620 nm. Among these, organometallic complexes having both a ligand having a pyrimidine ring or a pyrazine ring and a ligand having a quinoline ring are suitable for obtaining an electroluminescence spectrum with low emission intensity at 495 nm or less and a half-width of 90 nm to 120 nm.

[0148] ≪TADF material≫ The following materials can be used as TADF materials. TADF materials are materials that have a small difference between the S1 level and the T1 level (preferably 0.2 eV or less), can upconvert a triplet excited state to a singlet excited state with a small amount of thermal energy (reverse intersystem crossing), and efficiently emit light (fluorescence) from the singlet excited state. Conditions for efficiently obtaining thermally activated delayed fluorescence include an energy difference between the triplet excited energy level and the singlet excited energy level of 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0.1 eV or less. Delayed fluorescence in TADF materials refers to light emission that has a spectrum similar to that of normal fluorescence but has a significantly long lifetime. Its lifetime is 1×10 -6 seconds or more, preferably 1 x 10 -3 More than a second.

[0149] Examples of TADF materials include fullerene, fullerene derivatives, acridine derivatives such as proflavine, eosin, etc. Also included are metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complex (abbreviation: SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF2(OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (abbreviation: PtCl2OEP).

[0150] [ka]

[0151] Other examples include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxy) 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9, 9-Dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracen]-10'-one (abbreviation: ACRSA), 4-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)benzofuro[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm), 4-[4-(9'-phenyl-3,3'- Heteroaromatic compounds having a π-electron rich heteroaromatic compound and a π-electron deficient heteroaromatic compound, such as 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), may also be used.

[0152] In addition, a substance in which a π-electron-rich heteroaromatic compound and a π-electron-deficient heteroaromatic compound are directly bonded is particularly preferable because the donor property of the π-electron-rich heteroaromatic compound and the acceptor property of the π-electron-deficient heteroaromatic compound are both strong, thereby reducing the energy difference between the singlet excited state and the triplet excited state. Furthermore, a TADF material (TADF100) in which the singlet excited state and the triplet excited state are in thermal equilibrium may also be used as the TADF material. Such a TADF material has a short emission lifetime (excitation lifetime), which can suppress a decrease in the efficiency of light-emitting elements in the high-brightness region.

[0153] [ka]

[0154] In addition to the above, examples of materials capable of converting triplet excitation energy into luminescence include nanostructures of transition metal compounds having a perovskite structure. Nanostructures of metal halide perovskites are particularly preferred. Nanoparticles and nanorods are preferred as such nanostructures.

[0155] In the light-emitting layers (113, 113a, 113b, 113c), one or more substances having an energy gap larger than the energy gap of the light-emitting substance (guest material) may be selected and used as the organic compound (host material, etc.) used in combination with the above-mentioned light-emitting substance (guest material).

[0156] <Fluorescent host material> When the light-emitting substance used in the light-emitting layers (113, 113a, 113b, and 113c) is a fluorescent light-emitting substance, it is preferable to use, as the organic compound (host material) to be combined, an organic compound having a high energy level in a singlet excited state and a low energy level in a triplet excited state, or an organic compound with a high fluorescence quantum yield. Therefore, as long as the organic compound satisfies these conditions, a hole-transporting material (described above) or an electron-transporting material (described below) shown in this embodiment can be used.

[0157] Although some of the examples overlap with those described above, examples of the organic compound (host material) that can be preferably combined with the light-emitting substance (fluorescent light-emitting substance) include condensed polycyclic aromatic compounds such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives.

[0158] Specific examples of organic compounds (host materials) that are preferably used in combination with fluorescent materials include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9,10-diphenylanthracene (abbreviation: :DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-di Phenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazo (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)-biphenyl-4'-yl}-anthracene (abbreviation: FLPPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-Di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAn th), 1-[4-(10-[1,1'-biphenyl]-4-yl-9-anthracenyl)phenyl]-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3), 5,12-diphenyltetracene, 5,12-bis(biphenyl-2-yl)tetracene, etc.

[0159] <Phosphorescent host material> Furthermore, when the light-emitting substance used in the light-emitting layers (113, 113a, 113b, 113c) is a phosphorescent light-emitting substance, an organic compound having a triplet excitation energy greater than the triplet excitation energy (energy difference between the ground state and the triplet excited state) of the light-emitting substance can be selected as the organic compound (host material) to be combined. Note that when multiple organic compounds (for example, a first host material and a second host material (or assist material)) are used in combination with the light-emitting substance to form an exciplex, it is preferable to use these multiple organic compounds in combination with the phosphorescent light-emitting substance.

[0160] With this structure, it is possible to efficiently obtain light emission using Exciplex-Triplet Energy Transfer (ExTET), which is an energy transfer from an exciplex to a light-emitting substance. As a combination of multiple organic compounds, it is preferable to use one that easily forms an exciplex, and it is particularly preferable to combine a compound that easily accepts holes (hole transport material) with a compound that easily accepts electrons (electron transport material).

[0161] Although some of the examples overlap with those described above, examples of the organic compound (host material, assist material) that can be preferably combined with the light-emitting substance (phosphorescent light-emitting substance) include aromatic amines (organic compounds having an aromatic amine skeleton), carbazole derivatives (organic compounds having a carbazole ring), dibenzothiophene derivatives (organic compounds having a dibenzothiophene ring), dibenzofuran derivatives (organic compounds having a dibenzofuran ring), oxadiazole derivatives (organic compounds having an oxadiazole ring), triazole derivatives (organic compounds having a triazole ring), benzimidazole derivatives (benzo Examples of suitable metal complexes include organic compounds having an imidazole ring, quinoxaline (organic compounds having a quinoxaline ring) derivatives, dibenzoquinoxaline derivatives (organic compounds having a dibenzoquinoxaline ring), pyrimidine derivatives (organic compounds having a pyrimidine ring), triazine derivatives (organic compounds having a triazine ring), pyridine derivatives (organic compounds having a pyridine ring), bipyridine derivatives (organic compounds having a bipyridine ring), phenanthroline derivatives (organic compounds having a phenanthroline ring), furodiazin derivatives (organic compounds having a furodiazin ring), zinc and aluminum-based metal complexes, and the like.

[0162] Among the organic compounds, specific examples of the aromatic amine and carbazole derivative, which are organic compounds with high hole-transporting properties, are the same as the specific examples of the hole-transporting material described above, and any of these is preferable as the host material.

[0163] Specific examples of the dibenzothiophene derivatives and dibenzofuran derivatives, which are organic compounds with high hole transport properties among the above organic compounds, include 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), DBT3P-II, 2,8-dipheny Examples of suitable host materials include 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and 4-[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II).

[0164] Other preferred host materials include metal complexes having oxazole- or thiazole-based ligands, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ).

[0165] Specific examples of the organic compounds having high electron transport properties, such as oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, quinazoline derivatives, and phenanthroline derivatives, among the above organic compounds, include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) organic compounds containing heteroaromatic rings with polyazole rings, such as 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs); organic compounds containing heteroaromatic rings with pyridine rings, such as bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), and 2,2-(1,3-phenylene)bis[9-phenyl-1,10-phenanthroline] (abbreviation: mPPhen2P); The organic compounds, 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), and the like, all of which are preferred as host materials.

[0166] Specific examples of the pyridine derivatives, diazine derivatives (including pyrimidine derivatives, pyrazine derivatives, and pyridazine derivatives), triazine derivatives, and furodiazine derivatives, which are organic compounds with high electron transport properties among the above organic compounds, include 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), and 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II). 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3 -(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d ]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[(3'-dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylen-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluoren)-2-yl]-1 ,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothiophenyl]-2-phenyl-9H-carbazole (abbreviation: PC Examples of suitable host materials include organic compounds containing heteroaromatic rings with diazine rings, such as 2-[1,1'-biphenyl]-3-yl-4-phenyl-6-(8-[1,1':4',1''-terphenyl]-4-yl-1-dibenzofuranyl)-1,3,5-triazine (abbreviated as mBP-TPDBfTzn), 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as 6mBP-4Cz2PPm), and 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(1,1'-biphenyl-4-yl)pyrimidine (abbreviated as 6BP-4Cz2PPm).

[0167] Furthermore, among the above organic compounds, specific examples of metal complexes, which are organic compounds with high electron-transporting properties, include zinc- or aluminum-based metal complexes such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), and bis(8-quinolinolato)zinc(II) (abbreviation: Znq), as well as metal complexes having a quinoline ring or a benzoquinoline ring, all of which are preferable as the host material.

[0168] Other preferred host materials include polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy).

[0169] Furthermore, we have developed bipolar organic compounds with high hole-transporting and electron-transporting properties, such as 9-phenyl-9'-(4-phenyl-2-quinazolinyl)-3,3'-bi-9H-carbazole (abbreviation: PCCzQz), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 5-[3-(4,6-diphenyl-1,3,5-triazin-2yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1 Organic compounds having a diazine ring, such as 11-(4-[1,1'-diphenyl]-4-yl-6-phenyl-1,3,5-triazin-2-yl)-11,12-dihydro-12-phenyl-indolo[2,3-a]carbazole (abbreviation: mINc(II)PTzn), 11-(4-[1,1'-diphenyl]-4-yl-6-phenyl-1,3,5-triazin-2-yl)-11,12-dihydro-12-phenyl-indolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), and 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), can also be used as the host material.

[0170] <Electron transport layer> The electron transport layers (114, 114a, 114b) are layers that transport electrons injected from the second electrode 102 and the charge generation layers (106, 106a, 106b) by the electron injection layers (115, 115a, 115b) described later to the light emitting layers (113, 113a, 113b). The electron transport material used in the electron transport layers (114, 114a, 114b) has an electron mobility of 1×10 or less at a square root of an electric field strength [V / cm] of 600. -6 cm2 A substance having an electron mobility of 1 / Vs or higher is preferred. Note that other substances can be used as long as they have a higher electron transporting property than hole transporting property. The electron transport layer (114, 114a, 114b) functions as a single layer, but may also have a stacked structure of two or more layers. Note that the above mixed materials have heat resistance, so that by performing a photolithography process on the electron transport layer using such a mixed material, the influence of a thermal process on the device characteristics can be suppressed.

[0171] ≪Electron transport material≫ The electron transport material that can be used for the electron transport layer (114, 114a, 114b) can be an organic compound with high electron transport properties, such as a heteroaromatic compound. A heteroaromatic compound is a cyclic compound containing at least two different elements in the ring. The ring structure can be a three-, four-, five-, or six-membered ring, with a five- or six-membered ring being particularly preferred. The element contained in the heteroaromatic compound is preferably one or more of nitrogen, oxygen, or sulfur in addition to carbon. Heteroaromatic compounds containing nitrogen (nitrogen-containing heteroaromatic compounds) are particularly preferred, and it is preferable to use a material with high electron transport properties (electron transport material) such as a nitrogen-containing heteroaromatic compound or a π-electron-deficient heteroaromatic compound containing the same.

[0172] A heteroaromatic compound is an organic compound that contains at least one heteroaromatic ring.

[0173] The heteroaromatic ring has any one of a pyridine ring, a diazine ring, a triazine ring, a polyazole ring, an oxazole ring, a thiazole ring, etc. The heteroaromatic ring having a diazine ring includes a heteroaromatic ring having a pyrimidine ring, a pyrazine ring, a pyridazine ring, etc. The heteroaromatic ring having a polyazole ring includes a heteroaromatic ring having an imidazole ring, a triazole ring, or an oxadiazole ring.

[0174] The heteroaromatic ring also includes a fused heteroaromatic ring having a fused ring structure, such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a phlodiazin ring, or a benzimidazole ring.

[0175] Examples of heteroaromatic compounds include heteroaromatic compounds containing one or more of nitrogen, oxygen, and sulfur in addition to carbon, and examples of heteroaromatic compounds having a five-membered ring structure include heteroaromatic compounds having an imidazole ring, heteroaromatic compounds having a triazole ring, heteroaromatic compounds having an oxazole ring, heteroaromatic compounds having an oxadiazole ring, heteroaromatic compounds having a thiazole ring, and heteroaromatic compounds having a benzimidazole ring.

[0176] Furthermore, among heteroaromatic compounds containing one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a six-membered ring structure include heteroaromatic compounds having a heteroaromatic ring such as a pyridine ring, a diazine ring (including a pyrimidine ring, a pyrazine ring, and a pyridazine ring), a triazine ring, and a polyazole ring.Heteroaromatic compounds having a structure in which pyridine rings are linked include heteroaromatic compounds having a bipyridine structure and heteroaromatic compounds having a terpyridine structure.

[0177] Furthermore, examples of heteroaromatic compounds having a fused ring structure partially containing the above-mentioned 6-membered ring structure include heteroaromatic compounds having a fused heteroaromatic ring such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a phenanthroline ring, a furodiazine ring (including a structure in which an aromatic ring is fused to the furan ring of a furodiazine ring), and a benzimidazole ring.

[0178] Specific examples of the heteroaromatic compound having a five-membered ring structure (such as a polyazole ring (including an imidazole ring, a triazole ring, and an oxadiazole ring), an oxazole ring, a thiazole ring, and a benzimidazole ring) include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4)-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and the like.

[0179] Specific examples of the heteroaromatic compound having a 6-membered ring structure (including heteroaromatic rings having a pyridine ring, a diazine ring, a triazine ring, or the like) include heteroaromatic compounds having a pyridine ring, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB); Triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylen-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine ( abbreviation: mTpBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluoren)-2-yl]-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothiophenyl]-2-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-[1,1'-biphenyl]-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluoren)-2-yl]-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothiophenyl]-2-phenyl-9H-carbazole (abbreviation: PCDBfTzn), Heteroaromatic compounds containing heteroaromatic rings with a triazine ring, such as 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), mFBPTzn, 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), ...6-Bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviated as 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviated as 4,6mCzP2Pm), 4,6mCzBP2Pm, 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as 6mBP-4Cz2 PPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(1,1'-biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 4-[3-(dibenzothiophen-4-yl)phenyl]-8-(naphthalen-2-yl)-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 8BP-4mDBtPBfpm, 9mDBtBP Nfpr, 9pmDBtBPNfpr, 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviated as 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviated as 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(1,1'-biphenyl- and heteroaromatic compounds containing a heteroaromatic ring having a diazine (pyrimidine) ring, such as 8-[(2,2'-binaphthalen)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm). The aromatic compounds containing a heteroaromatic ring include heteroaromatic compounds having a fused heteroaromatic ring.

[0180] Other examples include 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), and 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6 mBP-4Cz2PPm), and other heteroaromatic compounds containing a heteroaromatic ring having a diazine (pyrimidine) ring; and heteroaromatic compounds containing a heteroaromatic ring having a triazine ring, such as 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tz), and 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn).

[0181] Specific examples of the heteroaromatic compound having a fused ring structure partially containing a 6-membered ring structure (heteroaromatic compound having a fused ring structure) include bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2-(1,3-phenylene)bis[9-phenyl-1,10-phenanthroline] (abbreviation: mPPhen2P), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline] (abbreviation: 2mDBTPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPD and heteroaromatic compounds having a quinoxaline ring, such as 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 7mDBTPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 6mDBTPDBq-II), 2mpPCBPDBq, etc.

[0182] In addition to the heteroaromatic compounds described above, the electron transport layers (114, 114a, 114b) may also include the following metal complexes: metal complexes having a quinoline ring or a benzoquinoline ring, such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq3), Almq3, 8-quinolinolatolithium(I) (abbreviation: Liq), BeBq2, bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), and bis(8-quinolinolato)zinc(II) (abbreviation: Znq); and metal complexes having an oxazole ring or a thiazole ring, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ).

[0183] In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used as electron transport materials.

[0184] The electron transport layer (114, 114a, 114b) may not only be a single layer, but also have a structure in which two or more layers made of the above-mentioned substances are stacked.

[0185] <Electron injection layer> The electron injection layers (115, 115a, 115b) are layers containing a substance with high electron injection properties. The electron injection layers (115, 115a, 115b) are layers for increasing the efficiency of electron injection from the second electrode 102, and it is preferable to use a material for the second electrode 102 having a work function whose difference in LUMO level is small (0.5 eV or less) compared with that of the material for the electron injection layers (115, 115a, 115b). Therefore, the electron injection layer 115 may contain any of lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF), 8-(quinolinolato)lithium (abbreviated as Liq), 2-(2-pyridyl)phenolatolithium (abbreviated as LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviated as LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviated as LiPPP), lithium oxide (LiO x Alkali metals, alkaline earth metals, such as cesium carbonate, or compounds thereof can be used. Rare earth metal compounds, such as erbium fluoride (ErF3) and ytterbium (Yb), can also be used. The electron injection layers (115, 115a, 115b) may be formed by mixing a plurality of the above materials, or by stacking a plurality of the above materials. Electrides may also be used for the electron injection layers (115, 115a, 115b). Examples of electrides include a substance in which a high concentration of electrons is added to a mixed oxide of calcium and aluminum. The substances constituting the above-mentioned electron transport layers (114, 114a, 114b) can also be used.

[0186] The electron injection layer (115, 115a, 115b) may also be made of a mixed material containing an organic compound and an electron donor (donor). Such a mixed material has excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent at transporting the generated electrons. Specifically, the electron transport materials (metal complexes, heteroaromatic compounds, etc.) used in the electron transport layer (114, 114a, 114b) described above can be used. The electron donor may be any substance that exhibits electron donating properties to the organic compound. Specific examples include alkali metals, alkaline earth metals, and rare earth metals, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides and alkaline earth metal oxides are also preferred, such as lithium oxide, calcium oxide, and barium oxide. Lewis bases such as magnesium oxide can also be used. Organic compounds such as tetrathiafulvalene (TTF) can also be used. Furthermore, a plurality of these materials may be laminated.

[0187] Alternatively, the electron injection layer (115, 115a, 115b) may be made of a mixed material containing an organic compound and a metal. The organic compound used here preferably has a LUMO (Lowest Unoccupied Molecular Orbital) level of -3.6 eV or more and -2.3 eV or less. A material having an unshared electron pair is also preferred.

[0188] Therefore, the organic compound used in the mixed material may be a mixed material obtained by mixing a heteroaromatic compound with a metal, as described above as being usable in the electron transport layer. Preferred heteroaromatic compounds include heteroaromatic compounds having a five-membered ring structure (such as an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, or a benzimidazole ring), heteroaromatic compounds having a six-membered ring structure (such as a pyridine ring, a diazine ring (including a pyrimidine ring, a pyrazine ring, or a pyridazine ring), a triazine ring, a bipyridine ring, or a terpyridine ring), and heteroaromatic compounds having a fused ring structure partially including a six-membered ring structure (such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, or a phenanthroline ring). Specific materials are described above, and therefore will not be described here.

[0189] As the metal used in the mixed material, it is preferable to use a transition metal belonging to Group 5, 7, 9 or 11 in the periodic table, or a material belonging to Group 13, such as Ag, Cu, Al or In. In this case, the organic compound forms a Singly Occupied Molecular Orbital (SOMO) with the transition metal.

[0190] For example, when light obtained from the light-emitting layer 113b is to be amplified, the optical distance between the second electrode 102 and the light-emitting layer 113b is preferably set to be less than ¼ of the wavelength λ of the light emitted by the light-emitting layer 113b. In this case, the optical distance can be adjusted by changing the film thickness of the electron-transporting layer 114b or the electron-injecting layer 115b.

[0191] Furthermore, as in the light-emitting device shown in FIG. 5D, by providing a charge generation layer 106 between two EL layers (103a, 103b), a structure in which multiple EL layers are stacked between a pair of electrodes (also called a tandem structure) can be obtained.

[0192] <Charge generation layer> The charge generation layer 106 has a function of injecting electrons into the EL layer 103a and injecting holes into the EL layer 103b when a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) 102. The charge generation layer 106 may be configured by adding an electron acceptor to a hole transporting material, or by adding an electron donor to an electron transporting material. Alternatively, both of these configurations may be stacked. By forming the charge generation layer 106 using the above-mentioned materials, it is possible to suppress an increase in driving voltage when EL layers are stacked.

[0193] When the charge generation layer 106 has a structure in which an electron acceptor is added to a hole-transporting material that is an organic compound, the material described in this embodiment can be used as the hole-transporting material. Examples of the electron acceptor include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ) and chloranil. Examples of the electron acceptor include oxides of metals that belong to Groups 4 to 8 of the periodic table. Specific examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide.

[0194] When the charge generation layer 106 has a structure in which an electron donor is added to an electron transporting material, the materials described in this embodiment can be used as the electron transporting material. As the electron donor, an alkali metal, an alkaline earth metal, a rare earth metal, or a metal belonging to Group 2 or Group 13 of the periodic table, or an oxide or carbonate thereof can be used. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, or the like can be preferably used. Alternatively, an organic compound such as tetrathianaphthacene can be used as the electron donor.

[0195] Although FIG. 5D shows a configuration in which two EL layers 103 are stacked, a stack structure of three or more EL layers may be formed by providing a charge generating layer between different EL layers.

[0196] <Substrate> The light-emitting device described in this embodiment mode can be formed on various substrates. Note that the type of substrate is not limited to a specific one. Examples of the substrate include a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having stainless steel foil, a tungsten substrate, a substrate having tungsten foil, a flexible substrate, a laminated film, paper containing a fibrous material, or a base film.

[0197] Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, soda lime glass, etc. Examples of flexible substrates, laminated films, base films, etc. include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), synthetic resins such as acrylic, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyamide, polyimide, aramid, epoxy resins, inorganic vapor deposition films, and papers.

[0198] The light-emitting device described in this embodiment can be fabricated by a gas-phase method such as vapor deposition, or a liquid-phase method such as spin coating or inkjet printing. When a vapor deposition method is used, a physical vapor deposition (PVD) method such as sputtering, ion plating, ion beam deposition, molecular beam deposition, or vacuum deposition, or a chemical vapor deposition (CVD) method can be used. In particular, layers having various functions included in the EL layer of the light-emitting device (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115) can be formed by a vapor deposition method (vacuum deposition, etc.), a coating method (dip coating, die coating, bar coating, spin coating, spray coating, etc.), a printing method (inkjet printing, screen (stencil printing), offset (lithographic printing), flexography (relief printing), gravure printing, microcontact printing, etc.), or the like.

[0199] When applying the above-mentioned coating method, printing method, or other film formation method, it is possible to use high molecular weight compounds (oligomers, dendrimers, polymers, etc.), medium molecular weight compounds (compounds in the intermediate range between low molecular weight and high molecular weight: molecular weight of 400 to 4000), inorganic compounds (quantum dot materials, etc.), etc. As quantum dot materials, colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, core-type quantum dot materials, etc. can be used.

[0200] The layers constituting the EL layer 103 of the light-emitting device described in this embodiment (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115) are not limited to the materials described in this embodiment, and other materials can be used in combination as long as they can fulfill the functions of each layer.

[0201] In this specification and the like, the terms "layer" and "film" can be used interchangeably as appropriate.

[0202] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0203] (Embodiment 3) In this embodiment, a structure of a light-emitting device in a lighting device of one embodiment of the present invention will be described with reference to Fig. 6. Fig. 6A is a cross-sectional view taken along line ef in the top view of the lighting device shown in Fig. 6B.

[0204] In the light-emitting device of this embodiment, a first electrode 401 is formed over a light-transmitting substrate 400, which serves as a support. The first electrode 401 corresponds to the first electrode 101 in Embodiment 2. When light is extracted from the first electrode 401 side, the first electrode 401 is formed using a light-transmitting material.

[0205] A pad 412 for supplying a voltage to the second electrode 404 is formed on the substrate 400 .

[0206] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the structure of the EL layer 103 in Embodiment 2. For details of these structures, refer to the description therein.

[0207] A second electrode 404 is formed to cover the EL layer 403. The second electrode 404 corresponds to the second electrode 102 in Embodiment 2. When light is extracted from the first electrode 401 side, the second electrode 404 is formed of a material with high reflectivity. The second electrode 404 is connected to a pad 412 to supply a voltage.

[0208] As described above, the light-emitting device described in this embodiment has a light-emitting device including the first electrode 401, the EL layer 403, and the second electrode 404. Since the light-emitting device has high emission efficiency, the lighting device in this embodiment can be a lighting device with low power consumption.

[0209] The lighting device is completed by bonding and sealing substrate 407, on which the light-emitting device having the above configuration is formed, to substrate 400 using sealants 405 and 406. Either sealant 405 or 406 can be used. Also, a desiccant can be mixed into inner sealant 406 (not shown in FIG. 6B), which can absorb moisture and improve reliability.

[0210] Furthermore, the pad 412 and a part of the first electrode 401 can be extended outside the sealing materials 405 and 406 to serve as an external input terminal. An IC chip 420 equipped with a converter or the like may also be provided thereon.

[0211] (Fourth embodiment) In this embodiment, an application example of a light-emitting device or a lighting device which is one embodiment of the present invention will be described with reference to FIGS.

[0212] As an indoor lighting device, it can be applied as a ceiling light 8001. Ceiling lights 8001 are available in types such as direct ceiling mount types and ceiling recessed types. Such lighting devices are constructed by combining a light emitting device with a shade, a housing, or a cover. It can also be applied to cord pendant types (types that hang from the ceiling with a cord).

[0213] The footlight 8002 can also project light onto the floor, improving safety around the feet. For example, it is effective for use in bedrooms, stairs, and corridors. In this case, the size and shape can be changed appropriately depending on the size and structure of the room. It can also be used as a stationary lighting device consisting of a light-emitting device and a support base.

[0214] The sheet lighting 8003 is a thin sheet-like lighting device. It is attached to a wall surface and can be used for a wide range of purposes without taking up much space. It can also be easily made into a large area. It can also be used on curved walls.

[0215] It is also possible to use a lighting device 8004 in which light from a light source is controlled to only a desired direction.

[0216] The desk lamp 8005 includes a light source 8006, and the light-emitting device according to one embodiment of the present invention or a light-emitting device that is a part of the light-emitting device can be used as the light source 8006.

[0217] In addition to the above, by applying the light-emitting device of one embodiment of the present invention or a light-emitting device that is a part of the light-emitting device to a part of furniture installed in a room, the lighting device can have the function of the furniture.

[0218] As described above, various lighting devices using the light-emitting device or lighting device according to one embodiment of the present invention can be obtained. Note that these lighting devices are also included in one embodiment of the present invention.

[0219] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments. [Example]

[0220] In this example, the light-emitting device of one embodiment of the present invention described in Embodiment 1 was actually manufactured, and the results of examining its operating characteristics will be described.

[0221] Fig. 8 shows a photograph of the appearance of the light emitting device 1 that was actually fabricated. Fig. 9 shows a graph of basic data f having 1 / f fluctuation characteristics for the light emitting device 1. Fig. 10 shows a graph of first smoothed data X and second smoothed data x for the light emitting device 1. Fig. 11 shows a graph of dimming data y for the light emitting device 1. In Figs. 9 to 11, the vertical axis represents the intensity of each data, and the horizontal axis represents the data number.

[0222] 8, the light emitting device 1 includes a light emitting device and a housing. The light emitting device has a light emitting area of ​​1142.75 mm 2An organic EL element measuring 35 mm×32.65 mm was used. The configuration of the light-emitting device used in this example will be explained in Example 2.

[0223] A method for adjusting the light intensity of the light emitting device 1 will be described with reference to FIGS.

[0224] First, basic data f having 1 / f fluctuation characteristics was created using a spreadsheet software (Fig. 9).

[0225] Next, moving average processing (simple moving average) with different intervals was performed on the basic data f having the 1 / f fluctuation characteristics shown in Fig. 9 to generate the first smoothed data X and the second smoothed data x shown in Fig. 10. The interval d1 of the moving average processing to generate the first smoothed data X was set to 30, and the interval d2 of the moving average to generate the second smoothed data x was set to 5.

[0226] It can be seen from FIG. 10 that by making d1 larger than d2, the waveform of the first smoothed data becomes smoother than the waveform of the second smoothed data.

[0227] Next, the first smoothed data X and the second smoothed data x shown in Fig. 10 were subjected to arithmetic processing to generate the dimming data y shown in Fig. 11. The arithmetic processing was performed according to the following formula.

[0228]

number

[0229] However, in the above formula, y i represents the i-th data of the dimming data y (0 to 1), and X i denotes the i-th data of the first smoothed data X, and x i represents the i-th data of the second smoothed data x. max represents the maximum value of X, and min represents the minimum value of X, UL represents the predetermined upper limit value of the X component, and LL represents the predetermined lower limit value of the X component.max represents the maximum value of x, and min represents the minimum value of x. Furthermore, A represents a predetermined contribution rate. In this example, calculation processing was performed with UL set to 0.9, LL set to 0.6, and A set to 0.1.

[0230] From FIG. 11, it can be seen that by performing the calculation process according to the above formula, the first smoothed data X and the second smoothed data x are combined to generate dimming data y that has sufficient smoothness and new 1 / f fluctuation characteristics.

[0231] The light emitting device 1 employed a PWM control method (100 Hz), and the brightness of the light emitting device 1 was changed over time in accordance with the dimming data thus generated. [Example]

[0232] In this example, the device structure and characteristics of light-emitting devices 1 to 3, which are organic EL elements that can be used in the light-emitting device described in Example 1, will be described. The specific configurations of light-emitting devices 1 to 3 are shown in the table below. The chemical formulas of the materials used in this example are also shown below. The light-emitting area of ​​light-emitting devices 1 to 3 shown in this example is 4 mm 2 (2mm x 2mm), but the light-emitting area is 1142.75mm 2 A light-emitting device (35 mm x 32.65 mm) can also be fabricated in a similar manner.

[0233] [Table 1]

[0234] [ka]

[0235] <<Fabrication of Light-Emitting Device 1>> The light-emitting device 1 shown in this example has a structure in which a hole injection layer 911, a hole transport layer 912, a light-emitting layer 913, an electron transport layer 914, and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a substrate 900, as shown in Figure 12, and a second electrode 903 is stacked on the electron injection layer 915.

[0236] First, a first electrode 901 was formed on a substrate 900. The electrode area was 4 mm 2 The dimensions were 2 mm×2 mm. A glass substrate was used as the substrate 900. The first electrode 901 was formed by depositing indium tin oxide containing silicon oxide (ITSO) by sputtering to a thickness of 70 nm.

[0237] Here, as a pretreatment, the surface of the substrate was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. -4 The substrate was placed in a vacuum deposition apparatus whose internal pressure had been reduced to about Pa, and vacuum-baked at 170°C for 60 minutes in the heating chamber of the vacuum deposition apparatus, after which the substrate was allowed to cool for about 30 minutes.

[0238] Next, a hole injection layer 911 was formed on the first electrode 901. The hole injection layer 911 was formed by evaporating the solution in a vacuum evaporation apparatus for 10 minutes. -4 After reducing the pressure to 10 Pa, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and a fluorine-containing electron acceptor material (OCHD-003) with a molecular weight of 672 were co-evaporated to form a 10 nm thick film at a weight ratio of 1:0.03 (= PCBBiF:OCHD-003).

[0239] Next, a hole transport layer 912 was formed on the hole injection layer 911. The hole transport layer 912 was formed by depositing PCBBiF to a thickness of 140 nm, and then depositing N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-bis(9,9-dimethyl-9H-fluoren-2-yl)amine (abbreviation: PCBFF) represented by the structural formula (ii) above to a thickness of 85 nm.

[0240] Next, a light-emitting layer 913 was formed on the hole-transporting layer 912. The light-emitting layer 913 was composed of 2-[3-(3'-dibenzothiophen-4-yl)biphenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) represented by the above structural formula (iii), PCBBiF, and bis[2-(2-quinolinyl-κN)phenyl-κC][2-(6-phenyl-4-pyrimidinyl-κN] 3 )phenyl-κC]iridium(III) (abbreviation: Ir(pqn)2(dppm)) was co-evaporated to a thickness of 50 nm in a ratio of 2mDBTBPDBq-II:PCBBiF:Ir(pqn)2(dppm) = 0.8:0.2:0.15.

[0241] Next, an electron transport layer 914 was formed on the light-emitting layer 913. The electron transport layer 914 was formed by vapor-depositing 2-[3′-(9,9-dimethyl-9H-fluoren-2-yl)-1,1′-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn) represented by the above structural formula (v) to a thickness of 10 nm, and then co-depositing 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn) represented by the above structural formula (vi) and 8-quinolinolato-lithium (abbreviation: Liq) represented by the above structural formula (vii) to a thickness of 25 nm such that mPn-mDMePyPTzn:Liq=1:1.

[0242] Next, an electron injection layer 915 was formed on the electron transport layer 914. The electron injection layer 915 was formed by vapor deposition using Liq so as to have a film thickness of 1 nm.

[0243] Next, a second electrode 903 was formed on the electron injection layer 915. The second electrode 903 was formed by vapor deposition of aluminum so as to have a film thickness of 200 nm. In this example, the second electrode 903 functions as a cathode.

[0244] Through the above steps, a light-emitting device 1 was formed on a substrate 900, with an EL layer sandwiched between a pair of electrodes. Note that the hole injection layer 911, hole transport layer 912, light-emitting layer 913, electron transport layer 914, and electron injection layer 915 described in the above steps are functional layers that constitute the EL layer in one embodiment of the present invention. Furthermore, in all of the vapor deposition steps in the above-described manufacturing method, vapor deposition using resistance heating was used.

[0245] The fabricated light-emitting device 1 was sealed in a glove box with a nitrogen atmosphere to prevent exposure to the air (a sealant was applied around the element, and during sealing, UV treatment was performed and heat treatment was performed at 80° C. for 1 hour).

[0246] <<Fabrication of light-emitting device 2>> Light-emitting device 2 is a light-emitting device that differs from light-emitting device 1 in the mixing ratio of each material in light-emitting layer 913. That is, light-emitting device 2 was fabricated in the same manner as light-emitting device 1, except that light-emitting layer 913 was formed by co-evaporating 2mDBTBPDBq-II, PCBBiF, and Ir(pqn)2(dppm) so that the ratio of 2mDBTBPDBq-II:PCBBiF:Ir(pqn)2(dppm) was 0.8:0.2:0.2.

[0247] <<Fabrication of Light-Emitting Device 3>> Light-emitting device 2 is a light-emitting device that differs from light-emitting device 1 in the light-emitting materials and mixing ratios of the materials used in light-emitting layer 913. That is, light-emitting device 3 was fabricated in the same manner as light-emitting device 1, except that instead of co-evaporating 2mDBTBPDBq-II, PCBBiF, and Ir(pqn)2(dppm), light-emitting layer 913 was co-evaporated with 2mDBTBPDBq-II, PCBBiF, and (diisobutyrylmethano)bis(4,6-(di-5-methylphenylpyrimidinato)iridium(III) (abbreviation: Ir(5mdppm)2(dibm)) represented by the above structural formula (viii) in a ratio of 2mDBTBPDBq-II:PCBBiF:Ir(5mdppm)2(dibm) = 0.8:0.2:0.1.

[0248] <Operation Characteristics of Light-Emitting Devices 1 to 3> The luminance-current density characteristics of light-emitting device 1 and light-emitting device 2 are shown in Fig. 13, the current efficiency-luminance characteristics in Fig. 14, the luminance-voltage characteristics in Fig. 15, the current-voltage characteristics in Fig. 16, the external quantum efficiency-luminance characteristics in Fig. 17, and the emission spectrum in Fig. 18. The luminance-current density characteristics of light-emitting device 3 are shown in Fig. 19, the current efficiency-luminance characteristics in Fig. 20, the luminance-voltage characteristics in Fig. 21, the current-voltage characteristics in Fig. 22, the external quantum efficiency-luminance characteristics in Fig. 23, and the emission spectrum in Fig. 24 ...1 to light-emitting device 3 at 1000 cd / m 2 The main characteristics in this range are shown in the table below. The luminance, CIE chromaticity, and emission spectrum were measured using a spectroradiometer (SR-UL1R, manufactured by Topcon Corporation) at room temperature.

[0249] [Table 2]

[0250] 13 to 24 and the above table, it was found that the light-emitting devices 1 to 3 according to embodiments of the present invention exhibited favorable operation characteristics.

[0251] 18, the maximum peak wavelengths of the emission spectra of light-emitting device 1 and light-emitting device 2 were 614 nm and 614 nm, respectively. The emission intensity at 495 nm or less in the emission spectrum of light-emitting device 1 was 1% or less of the emission intensity at the maximum peak wavelength. The emission intensity at 495 nm or less in the emission spectrum of light-emitting device 2 was 1% or less of the emission intensity at the maximum peak wavelength. The half-widths of the emission spectra of light-emitting device 1 and light-emitting device 2 were 91 nm and 90 nm, respectively.

[0252] 24, the maximum peak wavelength of the emission spectrum of the light-emitting device 3 was 612 nm. The emission intensity at wavelengths of 495 nm or less in the emission spectrum of the light-emitting device 3 was 1% or less of the emission intensity at the maximum peak wavelength. The half-width of the emission spectrum of the light-emitting device 3 was 79 nm.

[0253] That is, the light-emitting devices 1 to 3 emit light that is closer to natural light and suppress blue light, which can bring a relaxing effect to the user. Therefore, it was found that the use of the light-emitting devices 1 to 3 in the light-emitting device of one embodiment of the present invention can enhance the relaxing effect of the light-emitting device of one embodiment of the present invention. [Example]

[0254] In this example, the device structure and characteristics of light-emitting devices 4 to 6, which are organic EL elements that can be used in the light-emitting device described in Example 1, will be described. The specific configurations of light-emitting devices 4 to 6 are shown in the table below. The chemical formulas of the materials used in this example are also shown below. The light-emitting area of ​​light-emitting devices 4 to 6 shown in this example is 4 mm 2 (2mm x 2mm), but the light-emitting area is 1142.75mm 2 A light-emitting device (35 mm x 32.65 mm) can also be fabricated in a similar manner.

[0255] [Table 3]

[0256] [ka]

[0257] <<Fabrication of Light-Emitting Device 4>> Light-emitting device 4 is a light-emitting device that differs from light-emitting device 1 shown in Example 2 in the light-emitting materials and mixing ratios of the materials used in light-emitting layer 913. That is, light-emitting device 4 was fabricated in the same manner as light-emitting device 1 shown in Example 2, except that instead of co-depositing 2mDBTBPDBq-II, PCBBiF, and Ir(pqn)2(dppm) as light-emitting layer 913, 2mDBTBPDBq-II, PCBBiF, and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: Ir(dppm)2(acac)) represented by the above structural formula (ix) were co-deposited such that the ratio of 2mDBTBPDBq-II:PCBBiF:Ir(dppm)2(acac) was 0.8:0.2:0.2.

[0258] <<Fabrication of Light-Emitting Device 5>> Light-emitting device 5 differs from light-emitting device 1 described in Example 2 in the light-emitting materials and mixing ratios of the materials used in light-emitting layer 913 and the materials used in electron-transport layer 914. Specifically, in light-emitting device 5, instead of co-evaporating 2mDBTBPDBq-II, PCBBiF, and Ir(pqn)(dppm) to form light-emitting layer 913, 2mDBTBPDBq-II, PCBBiF, and (dipivaloylmethano)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: Ir(dppm)(dpm)) represented by the above structural formula (x) were co-evaporated such that the ratio of 2mDBTBPDBq-II:PCBBiF:Ir(dppm)(dpm) was 0.8:0.2:0.1. Furthermore, 2mDBTBPDBq-II was used instead of mFBPTzn to form electron-transport layer 914. Furthermore, instead of co-evaporating mPn-mDMePyPTzn and Liq, 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) represented by the above structural formula (xi) was evaporated as the electron transport layer 914. The rest of the process was the same as that of the light-emitting device 1 shown in Example 2.

[0259] <<Fabrication of Light-Emitting Device 6>> Light-emitting device 6 is a light-emitting device that differs from light-emitting device 5 in the mixing ratio of each material in light-emitting layer 913. That is, light-emitting device 6 was fabricated in the same manner as light-emitting device 5, except that light-emitting layer 913 was formed by co-evaporating 2mDBTBPDBq-II, PCBBiF, and Ir(dppm)2(dpm) so that the ratio of 2mDBTBPDBq-II:PCBBiF:Ir(dppm)2(dpm) was 0.8:0.2:0.3.

[0260] <Operation Characteristics of Light-Emitting Devices 4 to 6> The luminance-current density characteristics of light-emitting device 4 are shown in Fig. 25, the current efficiency-luminance characteristics in Fig. 26, the luminance-voltage characteristics in Fig. 27, the current-voltage characteristics in Fig. 28, the external quantum efficiency-luminance characteristics in Fig. 29, and the emission spectrum in Fig. 30. The luminance-current density characteristics of light-emitting device 5 and light-emitting device 6 are shown in Fig. 31, the current efficiency-luminance characteristics in Fig. 32, the luminance-voltage characteristics in Fig. 33, the current-voltage characteristics in Fig. 34, the external quantum efficiency-luminance characteristics in Fig. 35, and the emission spectrum in Fig. 36. The luminance-current density characteristics of light-emitting device 5 to light-emitting device 6 at 1000 cd / m 2 The main characteristics in this range are shown in the table below. The luminance, CIE chromaticity, and emission spectrum were measured using a spectroradiometer (SR-UL1R, manufactured by Topcon Corporation) at room temperature.

[0261] [Table 4]

[0262] 25 to 36 and the above table, it was found that the light-emitting devices 4 to 6, which are embodiments of the present invention, exhibited favorable operation characteristics.

[0263] 30, the maximum peak wavelength of the emission spectrum of light-emitting device 4 was 597 nm. The emission intensity at wavelengths of 495 nm or less in the emission spectrum of light-emitting device 4 was 1% or less of the emission intensity at the maximum peak wavelength. The half-width of the emission spectrum of light-emitting device 4 was 71 nm.

[0264] 36, the maximum peak wavelengths of the emission spectra of light-emitting device 5 and light-emitting device 6 were 597 nm and 600 nm, respectively. The emission intensities at wavelengths of 495 nm or less in the emission spectra of light-emitting device 5 and light-emitting device 6 were 1% or less of the emission intensities at the maximum peak wavelengths. The half-widths of the emission spectra of light-emitting device 5 and light-emitting device 6 were 72 nm and 73 nm, respectively.

[0265] That is, the light-emitting devices 4 to 6 have light emission that is closer to natural light and have reduced blue light, which can bring a relaxing effect to the user. Therefore, it was found that the use of the light-emitting devices 4 to 6 in the light-emitting device of one embodiment of the present invention can enhance the relaxing effect of the light-emitting device of one embodiment of the present invention. [Example]

[0266] In this example, the element structure and characteristics of light-emitting device 7, which is an organic EL element that can be used in the light-emitting device described in Example 1, will be described. The specific configuration of light-emitting device 7 is shown in Table 3. The chemical formulas of the materials used in this example are shown below. The structure of light-emitting device 7 is the same as that of light-emitting device 3 described in Example 2. The light-emitting area of ​​light-emitting device 7 is 1142.75 mm 2 (35mm x 32.65mm).

[0267] [Table 5]

[0268] [ka]

[0269] <<Fabrication of Light-Emitting Device 7>> As described above, the light-emitting device 7 shown in this example has the same layered structure as the light-emitting device 3 shown in Example 2, but is a light-emitting device with a different area of ​​the light-emitting portion. 2 The light-emitting device was fabricated in the same manner as the light-emitting device 3, except that a first electrode 901 (35 mm×32.65 mm) was formed.

[0270] <Operating characteristics of light-emitting device 7> The luminance-current density characteristics of the light-emitting device 7 are shown in Figure 37, the current efficiency-luminance characteristics in Figure 38, the luminance-voltage characteristics in Figure 39, the current-voltage characteristics in Figure 40, the external quantum efficiency-luminance characteristics in Figure 41, and the emission spectrum in Figure 42. 2 The main characteristics in this range are shown in the table below. The luminance, CIE chromaticity, and emission spectrum were measured using a spectroradiometer (SR-UL1R, manufactured by Topcon Corporation) at room temperature.

[0271] [Table 6]

[0272] 37 to 42 and the above table, it was found that light-emitting device 7, which is one embodiment of the present invention, exhibits favorable operating characteristics.

[0273] 42, the maximum peak wavelength of the emission spectrum of the light-emitting device 7 was 610 nm. The emission intensity at wavelengths of 495 nm or less in the emission spectrum of the light-emitting device 7 was 1% or less of the emission intensity at the maximum peak wavelength. The half-width of the emission spectrum of the light-emitting device 7 was 78 nm.

[0274] That is, the light-emitting device 7 emits light that is closer to natural light and suppresses blue light, which can provide a relaxing effect to the user. 2 The large surface area (35mm x 32.65mm) allows for softer light to be emitted, which is expected to have a greater relaxing effect.

[0275] (Reference synthesis example) In this synthesis example, the metal complex used in part of the light-emitting device in Example 2, bis[2-(2-quinolinyl-κN)phenyl-κC][2-(6-phenyl-4-pyrimidinyl-κN 3This article describes the synthesis of [Ir(pqn)2(dppm)], abbreviated as [Ir(pqn)2(dppm)]. The structural formula of [Ir(pqn)2(dppm)] is shown below.

[0276] [ka]

[0277] <Step 1: Synthesis of 2-phenylquinoline (abbreviation: Hpqn)> 7.8 g (38 mmol) of 2-bromoquinoline, 5.5 g (45 mmol) of phenylboronic acid, 113 mL of 2 M aqueous potassium carbonate, and 125 mL of 1,2-dimethoxyethane (DME) were placed in a 300 mL three-neck flask and the atmosphere inside the flask was replaced with nitrogen. 1.2 g (1.0 mmol) of tetrakis(triphenylphosphine)palladium was added to this mixture and heated to reflux at 90 °C for 3.5 hours. Water was added to the resulting reaction solution, which was then extracted with ethyl acetate. The resulting extract was washed with saturated brine, and the organic layer was dried over anhydrous magnesium sulfate. The resulting mixture was gravity filtered to obtain a filtrate. The filtrate was concentrated to obtain a solid. This solid was dissolved in toluene and suction-filtered through a Celite / alumina / Celite stack. The filtrate was concentrated to obtain a solid. The solid was purified by silica gel column chromatography. Toluene was used as the developing solvent. The resulting fraction was concentrated to obtain 7.3 g of a white solid in 95% yield. The synthesis scheme of step 1 is shown in formula (a-1) below.

[0278] [ka]

[0279] Step 2: Synthesis of di-μ-chloro-tetrakis[2-(2-quinolinyl-κN)phenyl-κC]diiridium(III) (abbreviation: [Ir(pqn)Cl]) 3 g (15 mmol) of Hpqn obtained by the synthesis method in Step 1 above, 1.97 g (6.6 mmol) of IrCl3·H2O, 81 mL of 2-ethoxyethanol, and 27 mL of water were placed in a three-neck flask and the atmosphere in the flask was replaced with argon. The mixture was irradiated with microwaves at 400 W and 100 °C for 1 hour to heat the reaction. After the specified time had elapsed, the resulting mixture was suction filtered, and the solid was washed with water and ethanol. The filtrate was concentrated and washed with water and then ethanol to obtain a solid. The solids obtained after the two suction filtrations were combined and washed with toluene to obtain 2.2 g of an orange solid in 53% yield. The synthesis scheme for Step 2 is shown in formula (a-2) below.

[0280] [ka]

[0281] Step 3: Bis[2-(2-quinolinyl-κN)phenyl-κC][2-(6-phenyl-4-pyrimidinyl-κN] 3 Synthesis of [)phenyl-κC]iridium(III) (abbreviation: [Ir(pqn)2(dppm)]) 2.2 g (1.73 mmol) of [Ir(pqn)Cl] obtained in Step 2 above and 200 mL of dichloromethane were placed in a three-neck flask, and a mixture of 0.89 g (3.5 mmol) of silver trifluoromethanesulfonate and 15 mL of methanol was added dropwise. The mixture was stirred at room temperature for 16 hours. After the specified time, the resulting mixture was filtered through Celite, and the filtrate was concentrated to obtain 2.32 g of a deep red solid. The resulting solid, 1.2 g (5.19 mmol) of 2,6-diphenylpyrimidine (abbreviation: Hdppm), and 130 mL of ethanol were placed in a three-neck flask and heated under reflux for 25 hours. The resulting mixture was concentrated, and 3 mL of ethanol was added and suction filtered. The resulting solid was purified by silica gel column chromatography. Dichloromethane was used as the developing solvent. 0.79 g of the resulting solid was further purified by high-performance liquid chromatography. Chloroform was used as the mobile phase solvent. The obtained solid was washed with hexane to obtain 0.680 g of a red solid in a yield of 24%. 0.59 g of the obtained red solid was purified by sublimation twice using the train sublimation method. The sublimation purification conditions were a pressure of 1.5 to 1.7 × 10 -3 The solid was heated at 285-295°C under 100 Pa with an argon flow rate of 0 mL / min. After purification by sublimation, the target red solid was obtained in a yield of 24%. The synthesis scheme of Step 3 is shown in the following formula (a-3).

[0282] [ka]

[0283] The protons ( 1 H) was measured by nuclear magnetic resonance (NMR). The values ​​obtained are shown below. 1 The H-NMR chart is shown in Figure 43. This shows that [Ir(pqn)2(dppm)] was obtained in this synthesis example.

[0284] 1H-NMR.δ(CD2Cl2):6.44(d,1H),6.55(t,2H),6.72-6.77(m,4H),6.83(t,1H),6.94-6.99(m,2H),7.04(t,1H),7.25-7.31(m,2H),7.48-7.49(m ,3H),7.66(d,1H),7.33-7.78(m,3H),7.92(d,1H),7.96(d,1H),8.05- 8.10(m,4H),8.13(d,1H),8.20(d,1H),8.25-8.29(m,2H),8.34(s,1H).

[0285] Next, the UV-visible absorption spectrum (hereinafter simply referred to as "absorption spectrum") and emission spectrum of a dichloromethane solution of [Ir(pqn)2(dppm)] were measured. The absorption spectrum was measured using a UV-visible spectrophotometer (V550, manufactured by JASCO Corporation). The dichloromethane solution (0.0123 mmol / L) was placed in a quartz cell, and measurements were performed at room temperature. The absorption spectrum was calculated by subtracting the absorption spectrum measured with only dichloromethane in the quartz cell from the absorption spectrum measured with the dichloromethane solution (0.0123 mmol / L) in the quartz cell. The emission spectrum was measured using an absolute PL quantum yield measurement system (C11347-01, manufactured by Hamamatsu Photonics K.K.). In a glove box (LABstar M13 (1250 / 780) manufactured by Bright Co., Ltd.), a deoxygenated dichloromethane solution (0.0123 mmol / L) was placed in a quartz cell under a nitrogen atmosphere, which was then sealed and measured at room temperature.

[0286] The measurement results of the absorption spectrum and emission spectrum are shown in Figure 44. The horizontal axis represents wavelength, and the vertical axis represents absorption intensity and emission intensity.

[0287] As shown in Figure 44, [Ir(pqn)2(dppm)] has an emission peak at 606 nm, and reddish-orange emission was observed from the dichloromethane solution. The half-width of the emission spectrum of [Ir(pqn)2(dppm)] was 104 nm. [Explanation of symbols]

[0288] 101: first electrode, 102: second electrode, 103: EL layer, 103a: EL layer, 103b: EL layer, 103c: EL layer, 106: charge generation layer, 106a: charge generation layer, 106b: charge generation layer, 111: hole injection layer, 111a: hole injection layer, 111b: hole injection layer, 112: hole transport layer, 112a: hole transport layer, 112b: hole transport layer, 113: light-emitting layer, 113a: light-emitting layer, 113b: light-emitting layer, 113c: light-emitting layer, 114: electron transport layer, 114a: electron transport layer, 114b: electron transport layer, 115: electron injection layer, 115a: electron injection layer, 115b: electron injection layer, 300: light-emitting device, 301: power supply, 302: dimming section, 303: light-emitting device, 310: lighting device, 310A: lighting device , 310B: lighting device, 311: shade, 311a: shade, 311b: shade, 312: base, 313: operation button, 320: light, 321: light, 330: remote controller, 400: substrate, 401: first electrode, 403: EL layer, 404: second electrode, 405: sealing material, 406: sealing material, 407: sealing substrate, 412: pad, 420: IC chip, 900: substrate, 901: first electrode, 903: second electrode, 911: hole injection layer, 912: hole transport layer, 913: light-emitting layer, 914: electron transport layer, 915: electron injection layer, 8001: ceiling light, 8002: foot lamp, 8003: sheet lighting, 8004: lighting device, 8005: desk lamp, 8006: light source

Claims

1. generating first smoothed data and second smoothed data by performing moving average processing with different intervals on basic data having 1 / f fluctuation characteristics; generating light control data by performing arithmetic processing on the first smoothed data and the second smoothed data; a dimming program that changes the brightness of a light-emitting device over time in accordance with the dimming data;

2. generating first smoothed data X and second smoothed data x by performing moving average processing with different intervals on basic data having 1 / f fluctuation characteristics; The first smoothed data X and the second smoothed data x are subjected to a calculation process according to the following formula to generate light adjustment data y: [Equation 1] a light-adjusting program that changes the brightness of a light-emitting device in a time series manner in accordance with the light-adjusting data y; (However, in the above formula, y ｉ represents the i-th data of the dimming data y, and X ｉ indicates the i-th data of the first smoothed data X, and x ｉ represents the i-th data of the second smoothed data x, and X ｍａｘ represents the maximum value of X, and X ｍｉｎ represents the minimum value of X, UL represents a predetermined upper limit value of the X component, LL represents a predetermined lower limit value of the X component, and x ｍａｘ represents the maximum value of x, and ｍｉｎ represents the minimum value of x, and A represents a predetermined contribution rate.

3. In claim 2, A light control program, wherein an interval of the moving average process for generating the first smoothed data X is greater than an interval of the moving average process for generating the second smoothed data x.

4. A light emitting apparatus having a light emitting device and a dimming unit, The light-emitting device has a function of generating first smoothed data and second smoothed data by performing moving average processing with different intervals on basic data having 1 / f fluctuation characteristics, generating light-control data by performing arithmetic processing on the first smoothed data and the second smoothed data, and changing the brightness of the light-emitting device over time in accordance with the light-control data.

5. A light emitting apparatus having a light emitting device and a dimming unit, The light adjustment unit performs moving average processing for different intervals on basic data having 1 / f fluctuation characteristics to generate first smoothed data X and second smoothed data x, and generates light adjustment data y by performing arithmetic processing on the first smoothed data X and the second smoothed data x according to the following formula: [Equation 2] A light emitting device having a function of changing the luminance of the light emitting device in a time series manner in accordance with the dimming data y. (However, in the above formula, y ｉ represents the i-th data of the dimming data y, and X ｉ indicates the i-th data of the first smoothed data X, and x ｉ represents the i-th data of the second smoothed data x, and X ｍａｘ represents the maximum value of X, and X ｍｉｎ represents the minimum value of X, UL represents a predetermined upper limit value of the X component, LL represents a predetermined lower limit value of the X component, and x ｍａｘ represents the maximum value of x, and ｍｉｎ represents the minimum value of x, and A represents a predetermined contribution rate.

6. In claim 5, A light emitting device, wherein an interval of moving average processing for generating the first smoothed data X is larger than an interval of moving average processing for generating the second smoothed data x.

7. In any one of claims 4 to 6, The light-emitting device comprises a first electrode, a second electrode, and an EL layer.

8. In any one of claims 4 to 7, A light emitting device, wherein the emission intensity at 495 nm or less in the electroluminescence spectrum of the light emitting device is 1% or less of the emission intensity at the maximum peak wavelength.

9. In any one of claims 4 to 8, A light-emitting device, wherein the peak wavelength of the electroluminescence spectrum of the light-emitting device is located at 590 nm or more and 625 nm or less.

10. In any one of claims 4 to 8, A light-emitting device, wherein the maximum peak wavelength of the electroluminescence spectrum of the light-emitting device is 590 nm or more and 625 nm or less.

11. In any one of claims 4 to 10, A light-emitting device, wherein the half-width of the electroluminescence spectrum of the light-emitting device is 75 nm or more and 120 nm or less.

12. In any one of claims 4 to 11, The light-emitting device has a CIE chromaticity (x, y) of 0.59 or more and 0.63 or less, and 0.37 or more and 0.41 or less.

13. A light emitting device comprising: the light emitting device according to any one of claims 4 to 12; and a shade; The lighting device, wherein the shade comprises a light-transmitting material.

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