JP2005190797A - Organic el device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL device which has a high degree of flexibility in display (lighting) and emits auxiliary light with low power consumption, and also to provide an electronic apparatus. <P>SOLUTION: In an organic EL device 100, an organic layer 104 including a light emitting layer made of an organic material is sandwiched between a transparent anode 102 formed on a transparent substrate 101 and a reflection cathode 103, and a driving circuit 106 supplies a voltage between the transparent anode 102 and the reflection cathode 105 to make the light emitting layer emit light and to drive pixel by pixel. A light storing material is distributed on an organic substance bank layer 103b for partitioning respective pixel areas. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an organic EL device and an electronic apparatus. Specifically, an organic layer including a light emitting layer made of an organic material is sandwiched between a first electrode and a second electrode formed on a substrate, and the first The present invention relates to an organic EL device and an electronic apparatus that apply a voltage between an electrode and a second electrode to cause the light emitting layer to emit light and drive the pixel unit.

  An organic EL device is a device having advantages such as being capable of high-luminance light emission, being a self-luminous planar display device, and being capable of being thinned. Such organic EL devices have recently been used for display devices and lighting devices. In the organic EL device, the luminous efficiency is greatly improved by laminating the organic layers and separating the functions, and high-luminance light emission is realized even when the applied voltage is low. The organic EL device usually has a configuration of substrate / first electrode / organic layer / second electrode. The organic material layer includes at least a light-emitting layer made of an organic material, and many layers further include a plurality of charge transport layers for improving device characteristics. When a voltage is applied to such an organic EL device, electrons are injected from one electrode into the light emitting layer, holes are injected from the other electrode, and organic molecules excited by recombination of the electrons and holes are grounded. Luminescence is obtained when the state relaxes. Since the organic EL device can emit light from the entire light emitting layer, the organic EL device becomes a planar light emitting element and takes out light through the first electrode side or the second electrode side of the element.

  On the other hand, recently, phosphorescent materials have attracted attention. Such a phosphorescent material refers to a material that emits "phosphorescence" after being exposed to sunlight or artificial lighting and the light is extinguished. Phosphorescent materials are widely applied to substitute materials for luminescent paint containing radioactive elements, emergency evacuation guide signs and life-saving emergency supplies that shine in the dark.

  As an organic EL device using a phosphorescent material, for example, Patent Document 1 is known. FIG. 10 is a diagram illustrating a configuration of an organic EL device 600 disclosed in Patent Document 1. As shown in the figure, the organic EL device 600 is formed of a phosphorescent material, and includes a display unit 601 for displaying a road sign, a glass plate 602, a hole injection electrode 603a, an electron injection electrode 603b, and an organic layer 603c. The display unit 601 includes an organic EL element (illumination device) 603 that irradiates light, and a power supply device 604 that intermittently supplies light to the organic EL element (illumination device) 603 to emit light intermittently. In this organic EL device 600, after the display portion 601 is irradiated with light by the organic EL element (illumination device) 603, afterglow is emitted from the display portion 601 formed of a phosphorescent material. It is not necessary to continuously illuminate with the lighting device 603, and sufficient display can be performed even at night with less power.

Japanese Patent Laid-Open No. 10-208524

  However, in the organic EL device of Patent Document 1, an organic EL element is used as a backlight. However, since driving in pixel units cannot be performed, power consumption is large when driving the organic EL element. In addition, there is a problem that only display of a standard form (road sign) can be performed.

  The present invention has been made in view of the above problems, and provides an organic EL device and an electronic apparatus that have a high degree of freedom of display (illumination) and can radiate auxiliary light with low power consumption. With the goal.

  In order to solve the above-described problems and achieve the object, the present invention sandwiches an organic layer including a light emitting layer made of an organic material between a first electrode and a second electrode formed on a substrate, In the organic EL device in which a voltage is applied between the first electrode and the second electrode to cause the light emitting layer to emit light and drive in units of pixels, a phosphorescent layer including a phosphorescent material is formed between the pixel regions. To do.

  As a result, the phosphorescent layer absorbs the energy of light such as sunlight, room light, and the light emitting layer, and can be used as auxiliary light even in the dark by illuminating visible light even when the light emitting layer does not emit light It becomes. In addition, the light emitting layer can be driven in units of pixels, so that the degree of freedom of display (illumination) is high and the power consumption can be reduced. Further, since the light storage layer is formed between the pixel regions, the light of the light emitting layer can be emitted outside without being blocked by the light storage layer, and display or illumination with high luminance is possible. As a result, it is possible to provide an organic EL device that has a high degree of freedom of display (illumination) and can emit auxiliary light with low power consumption.

  Moreover, according to a preferable aspect of the present invention, it is desirable that the phosphorescent layer is a bank layer separating pixel regions. Thereby, auxiliary light can be emitted from the bank layer.

  According to a preferred aspect of the present invention, the substrate is formed of a transparent substrate, emits light from the transparent substrate side, and the phosphorescent layer is formed between the pixel regions on the light emitting surface of the transparent substrate. It is desirable to be a stored phosphorescent film. Thereby, auxiliary light can be emitted from the phosphorescent film formed on the transparent substrate.

  Moreover, according to the preferable aspect of this invention, it is desirable for the said board | substrate to be formed with transparent luminous glass. As a result, the luminance of the auxiliary light can be increased.

  According to a preferred aspect of the present invention, it is desirable that the luminous layer is formed by an ink jet method. Accordingly, it is possible to form the phosphorescent layer with high accuracy and low cost without wasting materials as compared with methods such as vapor deposition.

  According to a preferred aspect of the present invention, it is desirable that the phosphorescent material is a phosphorescent material that emits green light. Thereby, it becomes possible to use auxiliary light that can be easily recognized by human eyes.

  According to a preferred aspect of the present invention, the organic layer is configured by alternately arranging red, green, and blue organic layers including red, green, and blue light-emitting layers, respectively, and the phosphorescent material is red A phosphorescent material that emits light is desirable. Thereby, the luminous layer including the luminous material that emits red light can efficiently absorb the energy of the light emitted from the blue light emitting layer and the green light emitting layer, and efficiently use the emitted light inside the organic EL device. Is possible.

  Moreover, according to the preferable aspect of this invention, it is desirable to mount the organic EL device of this invention in an electronic device. Thereby, it is possible to provide an electronic apparatus equipped with an organic EL device that has a high degree of freedom of display (illumination) and can emit auxiliary light with low power consumption.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The organic EL device of this embodiment can be widely applied to display devices, lighting devices, light source devices, and the like. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  FIG. 1 is a diagram showing a partial cross-sectional structure of an organic EL device 100 according to Example 1 of the present invention. The organic EL device 100 according to the first embodiment is a bottom emission type organic EL device driven by alternating current. In the figure, 101 is a transparent substrate, 102 is a transparent anode (first electrode), 103a is an inorganic bank layer, 103b is an organic bank layer (light storage layer), 104 is an organic layer including a light emitting layer made of an organic material, 105 is A reflective cathode (second electrode) 106 is a drive circuit that applies an AC voltage between the transparent anode 102 and the reflective cathode 105 to drive the pixel unit.

  On the transparent substrate 101, a transparent anode 102 made of ITO is formed and patterned in the pixel region. On the transparent substrate 101, an inorganic bank layer 103a and an organic bank layer 103b are sequentially stacked to form bank portions (partition walls) that separate the pixel regions.

The inorganic bank layer 103a is formed by forming an inorganic film such as SiO ₂ , TiO ₂ , or SiN on the entire surface of the transparent substrate 101 and the transparent electrode 101 by, for example, CVD, sputtering, vapor deposition, etc., and then etching the inorganic film. The patterning is performed by forming an opening in a pixel region on the transparent electrode 101.

  Next, an organic bank layer 103b containing a phosphorescent material is formed on the inorganic bank layer 103a. Specifically, after an ink composition containing an organic bank layer material is discharged onto the inorganic bank layer 103a by an ink jet apparatus (ink jet method), a drying process and a heat treatment are performed to form the inorganic bank layer 103a. As this ink composition, for example, an ink composition in which an organic resin in which a phosphorescent material is dispersed is dissolved in a solvent can be used. Here, as the phosphorescent material, for example, silicon aluminate or the like can be used. Moreover, as an organic resin, polymethylmethacrylate (PMMA), an acrylic resin, a polyimide resin etc. can be used, for example. Moreover, as a solvent, dimethylaniline, tetrahydrofuran (THF), benzene, cyclohexane etc. can be used, for example. The organic bank layer 103b is subjected to ink repellent treatment.

  An organic layer 104 including a light emitting layer made of an organic material is formed on the transparent anode 102. The organic layer 104 can be formed by applying a polymer organic material by an inkjet method. Note that a low molecular organic material may be formed by vapor deposition. The organic layer 104 is a single layer type (light emitting layer), two layer type (light emitting layer / hole injection layer), three layer type (electron transport layer / light emitting layer / hole transport layer), four layer type (electron injection layer). / Light emitting layer / hole transporting layer / hole injecting layer) and any of the five-layered types (electron injecting layer / electron transporting layer / light emitting layer / hole transporting layer / hole injecting layer) may be used. .

  A reflective cathode 105 made of Al / ITO or the like is formed on the entire surface of the organic layer 104 and the organic bank layer 103b. Note that a protective layer (sealing layer) may be formed on the reflective cathode 105.

  FIG. 2 shows a standard relative visibility curve of the human eye. In this figure, the horizontal axis indicates the wavelength, the vertical axis indicates the standard relative luminous sensitivity, and the highest sensitivity is shown as normalized sensitivity with “1”. As shown in FIG. 2, the human eye has the highest sensitivity to light having a wavelength of 555 nm, and has a sensitivity in the range of 380 nm to 760 nm. Therefore, in Example 1, it is desirable to use a phosphorescent material that emits G (green) light with the highest sensitivity of human eyes as the phosphorescent material.

  FIG. 3 is a diagram illustrating an example of an afterglow spectrum of the phosphorescent material that emits G light according to the first embodiment. As shown in the figure, it has a steep spectrum near 550 nm and emits light that is easily recognized by the human eye. FIG. 4 is a diagram illustrating an example of temporal transition of afterglow intensity of the phosphorescent material of Example 1. As shown in the figure, the afterglow intensity decreases with time, but afterglow is emitted for a predetermined time. Note that an organic material that emits green light is preferably used for the light-emitting layer of the organic layer 104. Thereby, the color of a normal display or illumination and the color of the auxiliary light (afterglow) by a phosphorescent material can be made the same, and it becomes an easy-to-see organic EL device.

  In the organic EL device 100 configured as described above, when an AC voltage is applied between the transparent anode 102 and the reflective cathode 105 by the drive circuit 106, the light emitting layer of the organic layer 104 emits light, and this emitted light is transmitted to the transparent substrate 101 side (light emission). Ejected from the surface side). In addition, since the phosphorescent material of the organic material bank layer 103b absorbs light emitted from the light emitting layer, sunlight, indoor light, and the like, and gradually releases this energy as visible light, this organic matter is emitted even when the light emitting layer 104 does not emit light. Visible light is illuminated from the light exit surface of the transparent substrate 101 from the bank layer 103b, and can be used as auxiliary light even in the dark.

  As described above, according to the organic EL device 100 of Example 1, the organic layer 104 including the light-emitting layer made of an organic material, the transparent electrode (first electrode) 102 formed on the transparent substrate 101, and the reflection The electrode (second electrode) 105 is sandwiched, and a voltage is applied between the transparent electrode 102 and the reflective electrode 105 by the drive circuit 106 to cause the light emitting layer to emit light and drive in units of pixels. Since the phosphorescent layer (organic bank layer 103b) is formed, the phosphorescent layer absorbs the energy of light such as sunlight, room light, and the light emitting layer, and emits visible light even when the light emitting layer does not emit light. Illuminated and can be used as auxiliary light even in the dark. In addition, the light emitting layer can be driven in units of pixels, so that the degree of freedom of display (illumination) is high and the power consumption can be reduced. Further, since the light storage layer is formed between the pixel regions, the light of the light emitting layer can be emitted outside without being blocked by the light storage layer, and display or illumination with high luminance is possible.

  Further, according to the first embodiment, since the phosphorescent layer is the organic bank layer 103b that separates the pixel regions, auxiliary light can be emitted from the organic bank layer 103b. In addition, according to Example 1, the organic material bank layer (phosphorescent layer) 103b is formed by the ink jet method, so that the organic material can be obtained with high accuracy and at low cost without wasting materials as compared with a method such as vapor deposition. The bank layer 103b can be formed. Moreover, according to Example 1, since the luminous material is made into the luminous material which emits G light, it becomes possible to make auxiliary light easy to recognize to human eyes.

  In Example 1, the transparent substrate 101 may be made of transparent luminous glass. As the transparent phosphorescent glass, for example, a zinc borosilicate glass containing the rare earth element terbium can be used. Thereby, it is possible to further increase the luminance of the auxiliary light.

  Further, the organic EL device 100 according to the first embodiment has been described with respect to the bottom emission type organic EL device, but the present invention can also be applied to a top emission type organic EL device.

  FIG. 5 is a diagram showing a partial cross-sectional structure of an organic EL device 200 according to Example 2 of the present invention. 5, parts having the same functions as those of the organic EL device 100 of FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 5, the organic EL device 200 according to the second embodiment is the same as the organic EL device 100 according to the first embodiment, and further a phosphorescent light emitting film (phosphorescent layer) between pixel regions on the light emission surface of the transparent substrate 101. 201 is formed. FIG. 6 is a partial plan view showing the positional relationship between the pixel electrode 102 and the phosphorescent film 201.

  The phosphorescent light-emitting film 201 is formed by performing a drying process and a heat treatment after ejecting an ink composition containing a phosphorescent light-emitting film material onto the light emission surface (back surface) of the transparent substrate 101 by an inkjet apparatus (inkjet method). . As this ink composition, for example, an ink composition in which an organic resin in which a phosphorescent material is dispersed is dissolved in a solvent can be used. Here, as the phosphorescent material, for example, silicon aluminate or the like can be used. As the organic resin, for example, polystyrene or polyurethane can be used. Moreover, as a solvent, tetrahydrofuran (THF), benzene, cyclohexane etc. can be used, for example. As the phosphorescent material, it is desirable to use a phosphorescent material that emits G as in the first embodiment.

  In the organic EL device 200 having the above-described configuration, the phosphorescent material of the phosphorescent light-emitting film (photoluminescent layer) 201 is used to store energy such as the light emitted from the light-emitting layer 104, sunlight, and room light, similar to the organic bank layer (photoluminescent layer) 103b. In order to absorb and gradually release this energy as visible light, even if the light emitting layer 104 does not emit light, visible light is illuminated from the light emitting surface side of the transparent substrate 101 from the light emitting and emitting film 201 to assist light even in the dark. Can be used. Further, since the phosphorescent light emitting film 201 is formed between the pixel regions, the light of the light emitting layer can be emitted to the outside without being shielded by the phosphorescent light emitting film 201, and display or illumination with high luminance is possible. Further, since the phosphorescent light emitting film 201 is formed by the ink jet method, it is possible to form the phosphorescent light emitting film 201 with high accuracy and low cost without wasting materials as compared with a method such as vapor deposition. .

  In Example 2, the phosphorescent layer is composed of the organic bank layer 103b and the phosphorescent light emitting film 201. However, the object of the present invention can be achieved even when the phosphorescent material is not used for the organic bank layer 103b. . Further, the organic EL device 200 according to the second embodiment has been described with respect to the bottom emission type organic EL device, but the present invention can also be applied to a top emission type organic EL device. In this case, the transparent anode 101 is a reflective anode, the reflective cathode 105 is a transparent cathode, a transparent sealing layer is formed on the transparent cathode, and the phosphorescent film 201 is formed on the sealing layer. good.

  FIG. 7 is a diagram showing a partial cross-sectional structure of an organic EL device 300 according to Example 3 of the present invention. In FIG. 7, parts having the same functions as those of the organic EL device 200 of FIG. The organic EL device 300 according to Example 3 is a full-color organic EL device. As shown in FIG. 7, the organic EL device 300 according to the third embodiment includes an R organic layer 104R, a G organic layer 104G, and a B organic layer 104B including R (red), G (green), and B (blue) light emitting layers. Are alternately arranged. A phosphorescent material that emits R light is used as the phosphorescent material of the organic bank layer 103b and the phosphorescent film 201. FIG. 8 is a diagram illustrating an example of an afterglow spectrum of the phosphorescent material that emits R light according to the third embodiment. R has the spectral sensitivity on the longest wavelength side among R, G, and B, and therefore can efficiently absorb the G emission light of the G organic layer 104G and the B emission light of the B organic layer 104B. The light emitted from the light emitting layer inside the EL device 300 can be efficiently absorbed and used as auxiliary light.

  In addition, you may decide to comprise the transparent substrate 101 with transparent luminous glass, and in this case, the luminous material which emits R light is used. Further, in Example 3, a phosphorescent material is used for both the organic bank layer 103b and the phosphorescent light emitting film 201, but the object of the present invention can be achieved even if a phosphorescent material is used for either one. Can do. In addition, the organic EL device 300 according to the third embodiment has been described with respect to the bottom emission type organic EL device, but can also be applied to a top emission type organic EL device.

(Application example to electronic equipment)
Next, specific examples of electronic devices to which the organic EL device according to the present invention can be applied will be described with reference to FIG. FIG. 9A is a perspective view showing an example in which the organic EL device according to the present invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) 400. As shown in the figure, a personal computer 400 includes a main body unit 402 having a keyboard 401 and a display unit 403 to which the organic EL device according to the present invention is applied. FIG. 9-2 is a perspective view showing an example in which the organic EL device according to the present invention is applied to the display unit of the mobile phone 500. As shown in the figure, a mobile phone 500 includes a plurality of operation buttons 501, a receiving part 502, a mouthpiece 503, and a display unit 504 to which the organic EL device according to the present invention is applied.

  The organic EL device according to the present invention includes a portable information device called PDA (Personal Digital Assistants), a personal computer, a workstation, a digital still camera, an in-vehicle monitor, a digital video camera, in addition to the above-described cellular phone and notebook computer. Can be widely applied to electronic devices such as liquid crystal televisions, viewfinder type, monitor direct view type video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, video phones, and POS terminals. .

  The organic EL device of the present invention can be widely used for display devices, electrochromic glass, electronic paper, lighting devices, light source devices, printer heads, and the like. The electronic device according to the present invention includes a mobile phone, a portable information device called PDA (Personal Digital Assistants), a portable personal computer, a personal computer, a workstation, a digital still camera, an in-vehicle monitor, a digital video camera, and a liquid crystal display. It can be widely used in electronic devices such as televisions, viewfinder type, monitor direct view type video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, video phones, and POS terminals.

1 is a partial cross-sectional view of an organic EL device according to Example 1 of the invention. The figure which shows the standard specific luminous efficiency curve of a human eye. The figure which shows an example of the afterglow spectrum of the luminous material of Example 1. FIG. The figure which shows an example of the time transition of the afterglow intensity | strength of the luminous material of Example 1. FIG. The fragmentary sectional view of the organic EL device concerning Example 2 of the present invention. The top view which shows the positional relationship of a pixel electrode and a luminous light emitting film. FIG. 6 is a partial cross-sectional view of an organic EL device according to Example 3 of the invention. The figure which shows an example of the afterglow spectrum of the luminous material of Example 3. FIG. The perspective view of the personal computer provided with the organic electroluminescent apparatus which concerns on an Example. The perspective view of the mobile telephone provided with the organic electroluminescent apparatus which concerns on an Example. The figure which shows the structure of the conventional organic EL apparatus.

Explanation of symbols

  100 organic EL device, 101 transparent substrate, 102 transparent anode (first electrode), 103a inorganic bank layer, 103b organic bank layer, 104 organic layer, 104RR organic layer, 104GG organic layer, 104BB organic layer, 105 reflective cathode (Second electrode) 106 is a drive circuit, 200 organic EL device, 201 photoluminescent film, 300 organic EL layer, 400 computer, 401 keyboard, 402 main body, 403 display unit, 500 mobile phone, 501 operation button, 502 Earpiece, 503 Mouthpiece, 504 Display unit, 600 Organic EL device, 601 Display unit, 602 Glass plate, 603 Organic EL element (illumination device), 603a Hole injection electrode, 603b Electron injection electrode, 603c Organic layer, 604 Power supply apparatus

Claims (8)

An organic layer including a light emitting layer made of an organic material is sandwiched between a first electrode and a second electrode formed on a substrate, and a voltage is applied between the first electrode and the second electrode to apply the light emitting layer. In an organic EL device that emits light and drives in units of pixels,
An organic EL device, wherein a phosphorescent layer containing a phosphorescent material is formed between each pixel region.   2. The organic EL device according to claim 1, wherein the phosphorescent layer is a bank layer separating pixel regions. The substrate is composed of a transparent substrate, and emits light from the transparent substrate side,
3. The organic EL device according to claim 1, wherein the phosphorescent layer is a phosphorescent light emitting film formed between pixel regions on the light emission surface of the transparent substrate.   The organic EL device according to any one of claims 1 to 3, wherein the substrate is made of a transparent phosphorescent glass.   5. The organic EL device according to claim 1, wherein the phosphorescent layer is formed by an ink-jet method.   6. The organic EL device according to claim 1, wherein the phosphorescent material is a phosphorescent material that emits green light. The organic layer is configured by alternately arranging red, green, and blue organic layers including red, green, and blue light-emitting layers, respectively.
The organic EL device according to claim 1, wherein the phosphorescent material is a phosphorescent material that emits red light.   An electronic apparatus comprising the organic EL device according to any one of claims 1 to 7.

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