KR101142876B1 - Organic electroluminescence device and its driving method - Google Patents

Abstract

It is an organic electroluminescent element in which the organic compound thin film containing a light emitting layer at least is arrange | positioned between an anode and a cathode. Using the sheet resistance of the anode or cathode, the luminance or color distribution in a single light emitting surface is driven to modulate with time. For example, at least one connection part is provided in at least one of an anode and a cathode, and a voltage is applied to each of these connection parts, and at least one of the amplitude, frequency, phase, and offset of the voltage applied to each connection part is modulated. As a result, a completely novel organic electroluminescent device capable of, for example, wave-like luminance modulation and color modulation on a single light emitting surface is realized.

Organic electroluminescent element, emitting surface, offset, phase, frequency, color modulation

Description

Organic electroluminescent device and its driving method {ORGANIC ELECTROLUMINESCENCE DEVICE AND ITS DRIVING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-luminous organic electroluminescent device and a method of driving the same. In particular, a luminance distribution and color distribution over time in a single light emitting surface of a large area organic electroluminescent device such as lighting applications It relates to a completely new driving technology for realizing light emission with.

An organic electroluminescent element (hereinafter referred to as an organic EL element) is a self-luminous type light source, which has advantages such as high response speed and no viewing angle dependence, and enlargement and flexibilization of pixels. Since the light is relatively easy, application to a wide range of fields such as lighting devices and displays is expected.

As the configuration of the organic EL device, for example, a transparent electrode (anode) made of indium tin oxide (ITO) is formed on a transparent glass substrate, and a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like are formed thereon. It is known to form a cathode or the like by vacuum deposition or the like. In the organic EL device having such a configuration, when a direct current voltage is applied between the transparent electrode as the anode and the cathode, holes (holes) injected from the transparent electrode through the hole injection layer move to the light emitting layer via the hole transport layer, and from the cathode Electrons injected through the electron injection layer move to the light emitting layer via the electron transport layer, and recombination of these electron-hole pairs occurs in the light emitting layer, resulting in light of a predetermined wavelength, which is observed on the transparent glass substrate side.

By the way, in the above-mentioned organic EL element, when trying to perform brightness modulation for a visual effect over time in a predetermined screen, for example, it is usually necessary to employ | adopt the structure as a display apparatus similarly to various displays. For example, in a display in which light emitting elements are arranged in a matrix, the luminance of one column of pixels is equally adjusted, and the luminance of each column is sequentially increased from left to right on the screen, and at a certain frequency, from left to right. Scroll horizontally to make the screen appear wavy. Such display cannot be realized unless there is a display panel in which a number of pixels (light emitting elements) are arranged, and a control device composed of a driver IC, a CPU, or the like for causing each of the pixels to emit light at an accurate and timely brightness.

As a display using an organic EL element, as disclosed in, for example, Japanese Patent Laid-Open No. 2003-76324, Japanese Patent Laid-Open No. 2002-91377, and the like, various types are known. It is necessary to arrange the pixels having the configuration in a matrix form, and a scan line, a signal line, a switching element, and a driving circuit for driving control of these are indispensable for these pixels.

However, in order to manufacture the above-described display panel and control device, a great deal of labor and cost are required, and for example, in the lighting device, when the luminance modulation is to be performed for the purpose of obtaining some visual effect, the same configuration as the display device is achieved. It is not very realistic to adopt it.

In recent years, the decorative lighting device and the auxiliary lighting device for interior use not only functions as a light source but also adds value such as dimming function and maintainability. If this is required and the luminance and the color can be modulated with a simple configuration, for example, a fantastic visual effect can be obtained, and the necessity is expected to be large.

The present invention has been proposed in view of the above conventional circumstances. That is, the present invention eliminates the need for a display panel in which pixels (light emitting elements) are arranged in a matrix, a driving circuit, a control device, and the like, which require a complicated circuit configuration, and for example, luminance modulation and color, such as waves, that are emitted from a light emitting surface. It is an object of the present invention to provide an entirely novel organic electroluminescent device that can be modulated, and to provide an illumination device or a decoration device as an application thereof. In addition, an object of the present invention is to provide a method for driving an organic electroluminescence element which can realize the above-mentioned luminance modulation and color modulation with a simple circuit configuration.

The present inventors have carried out various studies over a long time in order to achieve the above object. As a result, in an organic EL element having a large area of light emitting surface, such as for lighting, due to the resistance value of the electrode (anode or cathode), the applied voltage varies depending on the distance from the connecting portion, and the luminance modulation is used by using this. I have come to the conclusion that color modulation is possible.

The present invention has been devised based on a completely new idea unlike the conventional one. That is, in the organic electroluminescent device of the present invention, at least an organic compound thin film including a light emitting layer is disposed between an anode and a cathode, and the anode and the cathode are planar electrodes, and a light emitting surface having a predetermined area is configured. An organic electroluminescent device comprising: at least one of an anode and a cathode of the planar electrode is connected to a power supply through two or more connecting portions, and at least a portion of these connecting portions is applied with driving waveforms of different waveforms. Moreover, the illuminating device and the decorative device of this invention are equipped with such an organic electroluminescent element. It is characterized by the above-mentioned.

On the other hand, in the method of driving the organic electroluminescent device of the present invention, at least an organic compound thin film including a light emitting layer is disposed between an anode and a cathode, and the anode and the cathode are planar electrodes, and have light emission having a predetermined area. A method of driving an organic electroluminescent element having a plane, wherein the luminance and / or color are distributed in at least one light emitting plane, and the luminance and color distribution in the light emitting plane is time-lapsed. Drive to modulate according to the present invention.

In an organic EL device having a large light emitting area, for example, when a transparent electrode formed as a predetermined area under an organic compound thin film as an anode has a predetermined resistance value, voltage is not uniformly applied within the light emitting surface, but transparent The applied voltage varies with the distance from the connecting portion provided in the electrode. Here, for example, when a plurality (two or more) of connecting portions are provided in the transparent electrode, and driving voltages having different effective voltages, frequencies, phases, and the like are respectively applied to the connecting electrodes, the distances from the respective connecting portions are different. The driving voltage of the pattern is applied. As a result, light emission is performed with distribution in luminance and color in the light emitting surface. For example, a distribution state in which the luminance and the color are different in one emission surface is realized, such that the luminance is high in the portion within one light emitting surface and the luminance is low in the other portion. In this case, when the effective voltage, frequency, phase, and the like are properly controlled, the distribution state changes with time, for example, light emission accompanied with movement such as a screen wave in a single light emitting surface is realized. .

In the present invention, light emission accompanied with the above motion is performed in a single light emitting surface, and thus, it is not necessary to arrange the light emitting elements in a matrix like a display, and may have the same configuration as that of an organic EL element for ordinary lighting purposes. . In addition, some driving circuits are required to control the driving voltage applied to the connecting portion, but scanning lines, signal lines, switching elements corresponding to pixels, and complicated driving circuits for controlling the driving of them are not necessary.

Effects of the Invention

According to the present invention, there is no need for a display panel in which pixels (light emitting elements) are arranged in a matrix, a driving circuit, a control device, or the like requiring a complicated circuit configuration, and for example, luminance modulation and color such as waves that are emitted from a light emitting surface. It is possible to provide a completely novel organic electroluminescent element which can be modulated, and a driving method thereof. By applying this, it is possible to provide a high value-added lighting device or a decorative device.

1 is a schematic cross-sectional view showing the basic configuration of an organic EL element.

2 is a schematic diagram for explaining the principle of the present invention.

3 is a diagram showing an equivalent circuit at points a to d in the area between the connecting portions.

4 is a characteristic diagram showing a change in applied voltage in the region between the connecting portions when a voltage is applied to the connecting portion A. FIG.

5 is a waveform diagram illustrating an example of an applied voltage applied by the power sources C and D. FIG.

6 is a diagram showing an example of luminance modulation such as waves over time.

7 is a schematic plan view showing an organic EL device produced in an example.

8 is a schematic perspective view showing a connection example of the organic EL elements (two in-plane terminals) in the embodiment.

FIG. 9 is a schematic diagram showing the light emission behavior of each light emitting surface in the connection example shown in FIG. 8.

BEST MODE FOR CARRYING OUT THE INVENTION

EMBODIMENT OF THE INVENTION Hereinafter, the organic electroluminescent element and its drive method which apply this invention are demonstrated in detail, referring drawings.

The present invention is suitable for application to a large area organic EL device having a light emitting area exceeding 10 mm x 10 mm (= 100 mm ² ), for example, an organic EL device for lighting or decoration. This is because in organic EL devices having a small area of pixels, such as organic EL elements in displays, luminance modulation and color modulation in a single pixel are visually meaningless, and it is required to increase added value in organic EL elements for lighting and decoration. The reason for this is that the luminance modulation and the need for color modulation are high. So, in the following embodiment, it demonstrates a large area organic EL element, such as for illumination and decoration.

The basic configuration of the organic EL device of the present invention is not different from the general organic EL device. For example, as shown in FIG. 1, the transparent electrode 2 and the organic compound thin film functioning as an anode on the substrate 1 are shown. (3) and the cathode 4 are laminated | stacked in order, and an element part is comprised.

The board | substrate 1 functions as a support body which supports an element part, but also functions as a barrier layer which prevents penetration into an element part, such as moisture and oxygen. Although the constituent material of this board | substrate 1 is not specifically limited, For example, in the case of a bottom emission type organic electroluminescent element, since light emission is taken out through the board | substrate 1, it is preferable that it is a transparent material. Therefore, glass, plastic, etc. can be used, for example. Since glass is excellent also in barrier property, such as water and oxygen, it is a preferable material. When using plastic, since the said barrier property may be lacking, in that case, it is preferable to form a barrier layer on the surface.

Although an anode is formed on the said board | substrate 1, in the case of the above-mentioned bottom emission type organic electroluminescent element, it is preferable that this anode is also transparent. Therefore, it is usual for the anode to be a transparent electrode 2 formed of an inorganic transparent conductive material such as indium tin oxide (ITO), for example.

Although the organic compound thin film 3 is formed on the transparent electrode 2, as a structure, what is necessary is just to provide the minimum light emitting layer, for example, the hole injection layer 5, the hole transport layer 6, and the light emitting layer ( 7), the electron transport layer 8 and the electron injection layer 9 can be configured as a five-layer structure. Of course, it is not limited to this, The hole injection layer 5, the hole transport layer 6, the electron carrying layer 8, and the electron injection layer 9 can also be abbreviate | omitted suitably.

As a material which comprises each layer, all well-known thing can be used by organic electroluminescent element, There is no restriction | limiting in particular. For example, as the material of the hole injection layer 5, for example, 4,4 ', 4 "-tris [N- (1-naphthyl) -N-phenylamino] -triphenylamine (TNATA), TDATA, etc. Arylamines, phthalocyanines such as copper phthalocyanine (CuPc), Lewis acid doped organic layers, etc. Examples of the material for the hole transport layer 6 include aryl amines such as TPD, spiro TPD, NPD, TPAC, and the like. Can be mentioned.

As a material of the light emitting layer 7, a triarylamine derivative, a stilbene derivative, a polyarylene, an aromatic condensed polycyclic compound, an aromatic heterocyclic compound, an aromatic heterocondensed cyclic compound, a metal complex compound, etc. are mentioned, for example. Alternatively, an aluminum complex (Alq ₃ ), beryllium complex (Bebq ₂ ), or the like may be used as a host material, and a dopant dye may be doped into the host material. In this case, as a doping pigment, perylene, coumarin 6, quinacridone (Qd), rubrene, DCM, etc. are mentioned.

As a material of the electron carrying layer 8, aluminum complex, oxadiazoles, triazoles, phenanthroline, etc. are mentioned, for example. As a material of the electron injection layer 9, alkali metals, such as lithium, lithium fluoride, lithium oxide, a lithium complex, an alkali metal dope organic material, etc. are mentioned.

The negative electrode 4 superimposed on the organic compound thin film 3 is comprised from metal materials, such as aluminum, alloy materials, such as an aluminum-lithium alloy and a magnesium-silver alloy, etc., for example. The cathode 4 is formed by forming these metal materials or alloy materials by, for example, a vacuum thin film formation technique such as sputtering or vapor deposition.

In the present invention, two or more connecting portions connected to a power source are provided on either or both of the transparent electrode 2 or the cathode 4 of the organic EL element having the above-described configuration, and controlling the driving voltage applied to these connecting portions. Luminance modulation or color modulation is realized in which the distribution of luminance or color on a single light emitting surface changes over time. In this case, it is preferable that the electrode provided with two or more connection parts has a high resistance value to some extent, and specifically, it is preferable that sheet resistance is 20 ohms / square or more. If the sheet resistance is too low, it is impossible to give a predetermined voltage difference, which makes it difficult to modulate luminance or color in a visible form.

In general, since the transparent electrode 2 made of ITO has a relatively high sheet resistance, it is preferable as an electrode for providing the two or more connection portions. Since the cathode 4 is made of a metal or an alloy such as Al, the electrical resistance is small, and it is difficult to modulate at a normal film thickness. However, when the film thickness is thinned to increase the resistance value, the transparent electrode 2 and Similarly, the cathode 4 can be used as an electrode for providing two or more connection portions.

In the transparent electrode 2 or the cathode 4, the positions at which the connection portions are provided may be separated from each other, but it is preferable to arrange them with a certain distance. For example, in the case of emitting light as a wave in a square or rectangular light emitting surface, it is preferable to arrange the connecting portions on the outer sides of two opposite sides of the square or rectangular light emitting area, respectively.

Next, the principle of luminance modulation or color modulation over time in the organic EL element having the above-described configuration will be described.

As shown in FIG. 2, the structure of an organic electroluminescent element is the transparent electrode 2 which consists of ITO etc. on the board | substrate 1, the organic compound thin film 3 containing a light emitting layer, and the cathode 4 which consists of Al etc. It is formed by laminating. Here, connecting portions A and B are provided on both sides of the organic compound thin film 3 of the transparent electrode 2, respectively, and AC power sources C and D are connected to each of them as shown in a single light emitting surface. Think of the case to drive it.

As described above, the transparent electrode 2 made of ITO or the like has a predetermined resistance value, and is, for example, between the points a to d between the connection portion A to the connection portion B, for example. As shown in FIG. 3, the resistance R is equivalent to the presence of each. At this time, for example, the voltage of the AC power source connected to the connection portion A is applied to each point a to d in the form as shown in the equivalent circuit of Figs. 3 (a) to 3 (d). Therefore, the voltage applied to each point a-d changes with the distance from the connection part A by the voltage drop by each resistor R, for example, the voltage which is V1 in the connection part A. Even if is applied, as shown in FIG. 4, as it falls from the connection part A, it attenuates from Va to Vd. The same applies to the case where the voltage applied by the AC power source C is shaken from V1 to -V1, and the amplitude is large at the point a close to the connection A as shown by the lines in FIG. ), The amplitude becomes smaller.

The luminance distribution occurs due to the difference in amplitude at each of these points. The shape of the luminance distribution can be compared, for example, by shaking one end of a pencil as a supporting point. When one end of the pencil is supported and shaken at a certain speed, the human eye seems to be curved. Even when voltage is applied as shown in FIG. 4, the same phenomenon occurs as above, and an AC voltage having a predetermined frequency as shown in FIG. 4 is applied to the connection portion A while the potential of the connection portion B is applied. By vibrating at a predetermined amplitude and frequency as shown by the arrow in the figure, the luminance change from the connection part A to the connection part B is observed as a smooth luminance change under the influence of an afterimage.

The same applies to the connection portion B, and therefore, as shown in FIG. 5, for example, the voltage V _C applied by the power source _C and the voltage V _D applied by the power source D. FIG. By providing a predetermined phase difference or the like, the luminance modulation such as a wave of the screen is possible as shown in FIG. In Fig. 6, first, in Fig. 6 (a), the brightness at the left end is the highest in the drawing, but by gradually changing the voltage applied to each of the connection portions A and B, Figs. 6 (b) and 6 (c) are shown. As shown in Fig. 1), the region with the highest luminance gradually moves to the right in the drawing. In addition, as shown in Fig. 6D, the region with the highest luminance moves to the right end of the light emitting surface. On both sides of the region with the highest luminance, the luminance gradually decreases with a predetermined gradation, and in addition to the series of movements in the region with the highest luminance, fantastic light emission such as light waves in the entire screen is realized.

As mentioned above, although wave | undulation of the light emission between two mutually opposing sides of a light emitting area was demonstrated as an example, brightness modulation and color modulation are not limited to this, A various change is possible. For example, by providing the connection portion at three or more places, for example, it is possible to realize more complicated luminance modulation and color modulation. In addition, the voltage applied to each electrode can be subjected to luminance modulation and color modulation in various patterns by appropriately changing amplitude, offset, phase difference, frequency, and the like. In addition, the driving voltage waveform to be applied includes, for example, a sine wave and the like, and smooth luminance modulation and color modulation can be performed by this, but the present invention is not limited to this, and may be a triangular wave or a rectangular wave.

In particular, in the case of performing color modulation, a plurality of light emitting layers emitting colors of different colors may be provided in the organic compound thin film. At this time, by changing the voltage level required for light emission of each light emitting layer, color modulation is realized by the same voltage driving as described above.

Hereinafter, specific examples to which the present invention is applied will be described. In the present Example, in order to confirm the effect of this invention, the organic electroluminescent element was produced and the brightness modulation and the color modulation were tested.

Change of luminance distribution over time

The organic EL element of the structure shown in FIG. 7 was used for optimization of drive conditions. As shown in Fig. 7, the organic EL device is formed by laminating an organic compound thin film 3 and a cathode 4 made of Al on a glass substrate 1 on which a transparent electrode 2 made of ITO is formed. In the drawing, an oblique region is a light emitting region. The substrate size is 100 mm wide and the light emitting area is 75 mm wide.

The organic compound thin film 3 has a four-layer structure of CuPc (200 Pa) / α-NPD (300 Pa) / Alq ₃ (1000 Pa) / LiF (10 Pa). In addition, the thickness of the cathode 4 made of Al was 800 kPa. Film formation of each layer was performed by resistance heating method. In addition, the organic EL element was sealed using the glass cap.

Using such an organic EL element, the time-dependent change of the luminance distribution in the organic EL element was tested by the drive patterns 1 to 4 shown in Table 1 below. At this time, the voltage of the cathode 4 was fixed at 0V. In addition, both terminals of the light emitting region of the transparent electrode 2 serving as an anode were set to Ch1 and Ch2, respectively, and a sine wave voltage was applied to both of them. First, the change in luminance distribution over time is likened to a bent by shaking a pencil, but when applied to it, Ch1 is the support point of the pencil, Ch2 becomes the pencil tip, and the point of movement of the support point and the pencil tip (frequency, amplitude, etc.). ) Corresponds to each parameter in Table 1.

(1) drive pattern 1

In the drive pattern 1, blinking display was performed, and the whole surface was literally turned on and off repeatedly. At this time, the contrast was assured by raising the amplitude of Ch1.

(2) drive pattern 2

In the driving pattern 2, a display similar to the bar display seen in an audio apparatus or the like is realized. The Ch1 side is always lit, and a line drawn in the longitudinal direction has moved left and right (Ch1⇔Ch2). By raising the offset of Ch2, the luminance on the Ch1 electrode side can be lowered, and the movement becomes clear.

(3) drive pattern 3

In the driving pattern 3, an image in which waves represented by a gradient of luminance are pushed from left to right (right to left) is realized. By raising the amplitude of Ch2, the luminance on the Ch2 side increases and the afterglow becomes deeper. In addition, the motion of the wave is closely related to each of the parameters of Ch1 and Ch2, and when each parameter is changed, it is necessary to adjust the phase difference as well. In the case of the parameter of this drive pattern, the wave pushed from the left to the right arrives at the Ch2 side, and after all the lights are turned on, the brightness is lowered from the left to the right, and the lights are all turned off. In addition, the phase difference between Ch1 and Ch2 is reversed in the traveling direction of the wave at ± 90 °.

(4) drive pattern 4

In the driving pattern 4, an image in which the wave represented by the gradient of luminance is pushed, similar to the driving pattern 3, is realized. In the case of the driving parameter, the wave pushed from the left to the right reaches the Ch2 side, Luminance began to fall and disappeared from left to right at the same speed that was pushed. When the phase difference between Ch1 and Ch2 is ± 90 °, the wave propagation direction is reversed as in the case of the previous drive pattern 3.

As described above, it is possible to cause various changes in display, that is, the luminance distribution, over time by manipulating sine wave parameters. Incidentally, the voltage waveform to be applied is not limited to the sine wave, and may be a triangular wave or a rectangular fire, but the display is unique according to the applied waveform. The use of a sine wave makes the change in luminance distribution particularly smooth over time, and is effective when an organic EL is used for interior lighting or the like.

In this embodiment, the frequency is fixed simply for explaining the basic display. However, the frequency may be changed at all. For example, if the frequencies of Ch1 and 2 are raised equally, the wave speed increases if the wave is displayed. When the frequencies of Ch1 and 2 are set to different values, flickering, bar display, and wave display appear laterally.

In addition, although the display using the electrical resistance of the ITO electrode (transparent electrode 2) was demonstrated in the present Example, it is also possible to display using the electrical resistance of Al electrode (cathode 4). In that case, the ITO electrode is fixed at 0 V, and the offset of the sine wave voltage to be applied becomes a negative voltage. It is also possible to apply a sine wave voltage simultaneously to the ITO electrode side and the Al electrode side. In this case, waves generated in the horizontal direction and the vertical direction are superimposed to enjoy a more complicated and interesting change in luminance distribution over time.

Specific example in case of two in-plane terminals

In this example, two organic EL elements shown in FIG. 2 were used as light emitting units, and two of them were connected to test driving. The connection state of two organic electroluminescent elements is shown in FIG. In addition, the structure of each organic EL element is the same as that shown in previous FIG. Therefore, the same components as shown in Fig. 2 are denoted by the same reference numerals, and the description thereof is omitted here.

The drive voltage was applied to the organic EL element of the said connection structure under the following drive conditions, and the light emission was tested.

Driving condition

Cathode-anode applied waveform (drive voltage waveform by AC power supply): sine wave (amplitude: 10V, offset: 5V, frequency 2Hz)

A-B applied waveform (drive voltage waveform by AC power supply): sine wave (amplitude: 6V, offset: 0V, frequency 1Hz)

Phase difference of drive voltage waveform of AC power source (C) and AC power source (D): 120 degrees

As a result, as shown in Figs. 9A to 9C, light emission in various patterns was realized in each of the organic EL elements EL1 and EL2. 9 (a) to 9 (c), the arrow indicates the moving direction of the high luminance light emitting region. For example, as shown in FIG. 9 (a), the high luminance light emitting region is displayed in each of the organic EL elements EL1 and EL2. As shown in Fig. 9 (b), high luminance light emitting regions move from right to left in the organic EL elements EL1 and EL2 as shown in Fig. 9B. In addition, as shown in Fig. 9C, the same behavior as that of the high luminance light emitting region reciprocating in each of the organic EL elements EL1 and EL2 was also observed. These behaviors were synchronized with the organic EL element EL1 and the organic EL element EL2 by timing, and various changes were observed, such as a slight shift | offset | difference.

Changes in color distribution over time

Here, it was tested to express the color distribution in the light emitting region and to modulate it. The board | substrate size of the produced organic electroluminescent element is 50 mm wide, and the light emitting area size is 20 mm x 30 mm. In addition, as the layer structure of the organic compound thin film 3, CuPc (200 Pa) / alpha-NPD (300 Pa) / perylene 1% doping CBP (200 Pa) / rubrene 1% doping Alq ₃ (200 Pa) / Alq ₃ (100 Pa) ) / LiF (10 ms) was used as a six-layer structure. In addition, the thickness of the cathode 4 made of Al was 2000 kPa. Film formation of each layer was performed by resistance heating method. The produced organic EL element was sealed using the glass cap.

In the evaluation of the color distribution, since the color change is determined by the magnitude of the applied voltage, the same driving conditions as in the case of the change in the luminance distribution over time may be used. When the applied voltage is low, perylene close to the hole transport layer α-NPD emits blue light. When the voltage is increased, rubrene also gradually starts to emit yellow light, and when light emission is observed from the glass surface, it is understood that blue and yellow mixed light is emitted. For example, when the display is performed by the above drive pattern 1, when the applied voltage is maximized (the amplitude / 2 + offset voltage of Ch1 + the amplitude / 2 + offset voltage of Ch2 = 20.5VMax), the most rubrene emits light. Then, the color becomes pastel yellow near (0.27, 0.38) in the CIE chromaticity coordinates. At low voltage, only perylene emits light and is pale blue near (0.22, 0.40) in the CIE chromaticity coordinates. For this reason, the color change by the applied voltage was not simply linearly moving said two points, but was observed by the mixed color between the coordinates of two points. In addition, since the light emission color changes depending on the concentration of the dopant and the film thickness (influence of the optical resonant structure) of the element, it is necessary to set these properly according to the desired color change.

Claims (11)

An organic electroluminescent device comprising at least an organic compound thin film including a light emitting layer disposed between an anode and a cathode, wherein the anode and the cathode are planar electrodes, and a light emitting surface having a predetermined area is formed. At least one of the positive electrode and the negative electrode of the planar electrode is connected to a power source through two or more connecting portions, and at least a part of these connecting portions is applied with a driving voltage having a different waveform. The method according to claim 1, wherein at least one of luminance and color is changed in at least one light emitting surface by application of a driving voltage of the other waveform, and the distribution state of luminance and color in the light emitting surface is changed. An organic electroluminescent device, characterized in that it is driven to modulate with time. The organic electroluminescent device according to claim 1 or 2, wherein the planar electrode connected to the power supply via the two or more connection portions has a sheet resistance of 20? /? The organic material according to claim 1 or 2, wherein the anode is formed of indium tin oxide, the sheet resistance is a planar electrode of 20? /? Or more, and the connecting portions are formed at two locations of the anode. Electroluminescence element. The organic electroluminescent device according to claim 1, wherein the size of one light emitting surface is 10 mm x 10 mm or more. The organic electroluminescent element of Claim 1 is provided, The illuminating device characterized by the above-mentioned. The organic electroluminescent element of Claim 1 is provided, The decorative apparatus characterized by the above-mentioned. A method of driving an organic electroluminescence device, wherein at least an organic compound thin film including a light emitting layer is disposed between an anode and a cathode, and the anode and the cathode are planar electrodes, and a light emitting surface having a predetermined area is formed. Luminance in the light emitting surface is at least one of the luminance and the color in at least one light emitting surface by using a different voltage applied corresponding to the distance from the connection portion provided in the planar electrode. And driving the color distribution state to modulate with time. 9. An organic electroluminescent electrode according to claim 8, wherein at least one of the positive electrode and the negative electrode of the planar electrode is connected to a power supply through two or more connecting portions, and a driving voltage having a different waveform is applied at at least a part of these connecting portions. Method of driving luminescence element. 10. The method of claim 9, wherein the driving voltages of the different waveforms are different in amplitude, frequency, phase, and offset of an applied voltage. The driving method of claim 10, wherein the driving voltages of the different waveforms are driving voltages of sine waves having different phases.

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