JP2006310075A - Organic electroluminescence light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescence light-emitting device appropriate for constituting a printing head, an image display, or the like for emitting high-purity light and obtaining high-definition images that have improved reproducibility. <P>SOLUTION: The organic electroluminescence light-emitting device A1 has a red luminous section 11R, a green luminous section 11G, and a blue luminous section 11B for emitting red, green, and blue light as a plurality of organic electroluminescence luminous sections 11. The organic electroluminescence light-emitting device A1 has a light absorption means for absorbing, at least one of the lights at the intermediate wavelength region of red and green light or light at the intermediate wavelength region of green and blue light from light generated at the plurality of organic electroluminescence luminous sections 11. The light absorption means is constituted by dispersing and mixing a light absorbent, for example, to a substrate 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic EL light emitting device configured as a photosensitive print head, an image display device, or the like.

  In recent years, those using organic EL have become widespread as light emitting means for photosensitive print heads and image display devices. The organic EL has a basic structure in which a light emitting layer containing an organic phosphor is sandwiched between a cathode and an anode, and the light emitting layer (organic phosphor) emits light by an electric field applied using the cathode and the anode ( For example, see Patent Documents 1 to 3). For this reason, the organic EL can be driven at a low voltage and has an advantage of excellent responsiveness.

  When a photosensitive color print head is configured using such an organic EL, a plurality of organic EL light emitting sections capable of emitting light of the three primary colors of red, green, and blue are provided. In this case, in order to improve the image quality of the color print image, it is necessary to emit light of three primary colors with a small half width from each organic EL light emitting unit.

  However, as described above, since the organic EL emits light from the organic phosphor, the purity of the emitted light depends on the nature of the organic phosphor. For example, the half-value width of the emitted light is larger than that of the LED. There was a peculiar problem that the color purity was low. Specifically, for example, as shown in FIG. 2A, each of the red light SR, the green light SG, and the blue light SB emitted from the organic EL is longer than the short wavelength side with respect to their peak wavelengths. On the wavelength side, the emission intensity tends to be higher, and the half width is larger. For this reason, as shown in FIG. 5B, when the red light SR, the green light SG, and the blue light SB are combined, an intermediate wavelength region between red and green, and an intermediate wavelength region between green and blue. The emission intensity of becomes relatively high. Therefore, in the conventional print head and image display device using organic EL, the reproducibility of the print image or the display image is slightly inferior, and there is still room for improvement in obtaining a high-quality image. It was.

JP 2003-94729 A JP-A-11-95723 JP-A-9-212128

  The present invention has been made in view of the above-described circumstances, and is capable of emitting high-purity light and capable of obtaining a high-quality image with excellent reproducibility, an image display device, and the like. An object of the present invention is to provide an organic EL light-emitting device that is suitable for constituting the above.

  The organic EL light-emitting device provided by the first aspect of the present invention includes, as a plurality of organic EL light-emitting units, a red light-emitting unit, a green light-emitting unit, and a blue light-emitting unit that individually emit red light, green light, and blue light, respectively. An organic EL light-emitting device having a light emitting portion, wherein the light emitted from the plurality of organic EL light-emitting portions is light in an intermediate wavelength region of the red light and the green light, and the green light and the blue light. The light-absorbing means for absorbing at least one of the light in the intermediate wavelength region of the light is provided.

  According to such a configuration, the intensity of at least one of light in the intermediate wavelength region of red light and green light and light in the intermediate wavelength region of green light and blue light is reduced, and red light, green light, and blue light are reduced. The full width at half maximum of all of the light or two of the color lights is reduced, and the purity of the light is increased. As a result, for example, when configured as a print head or an image display device, the color reproducibility of the print image or the display image is excellent, and a high-quality image can be obtained.

  In a preferred embodiment of the present invention, the light absorbing means has a first light absorption band having an absorption wavelength peak in a wavelength range of 550 to 600 nm and an absorption wavelength peak in a wavelength range of 490 to 515 nm. A second light absorption band.

  According to such a configuration, it is more preferable to reduce the half-value widths of the red light having a peak wavelength of about 620 nm, the green light of about 530 nm, and the blue light of about 470 nm to increase the purity of the light of these three colors. It becomes.

  In a preferred embodiment of the present invention, the plurality of organic EL light emitting units are formed on a substrate, and light emitted from the plurality of organic EL light emitting units is configured to pass through the substrate. In addition, since the light absorber is dispersed in the substrate, the substrate is configured as the light absorbing means.

  According to such a configuration, since the substrate serving as the base member of the organic EL light emitting unit is used as the light absorbing means, the configuration is reasonable, and the number of parts is increased and the overall size is increased. You can avoid inviting them.

  In a preferred embodiment of the present invention, the plurality of organic EL light emitting units are formed on a substrate, and light emitted from the plurality of organic EL light emitting units is configured to pass through the substrate. The light absorbing means is laminated on the light emitting surface of the substrate. In this case, the light absorbing means can be configured as a light absorbing coating layer or a sheet or film light absorbing filter.

  According to such a configuration, the function intended by the present invention can be obtained by a simple configuration in which the light absorbing means is simply laminated on the substrate, and its manufacture is easy.

  In a preferred embodiment of the present invention, it is configured as an organic EL print head for irradiating a photosensitive recording medium with light to form an image, or as an organic EL display device for displaying an image. However, it goes without saying that the organic EL light emitting device according to the present invention can be configured as a device or equipment other than those described above.

  The organic EL light-emitting device provided by the second aspect of the present invention is an organic EL light-emitting device including an organic EL light-emitting unit that emits red light, green light, or blue light. Light absorbing means for absorbing light in the wavelength region of the bottom region different from the peak wavelength region of this light from the light generated in step.

  According to such a configuration, it becomes possible to increase the purity of red light, green light, or blue light emitted from the organic EL light emitting unit, and also a print head or an image display device is configured using this organic EL light emitting device. In this case, the quality of the recorded image or display image can be improved.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a main part of an organic EL light emitting device according to the present invention. The organic EL light emitting device A1 of this embodiment includes a substrate 10 and a plurality of organic EL light emitting units 11.

  As the plurality of organic EL light emitting units 11, there are a red light emitting unit 11R, a green light emitting unit 11G, and a blue light emitting unit 11B that can individually emit red light, green light, and blue light, respectively. These organic EL light emitting units 11 are formed by laminating a transparent anode 12, a plurality of organic layers 13, and a plurality of cathodes 14 on one surface of the substrate 10. An insulating layer (not shown) is appropriately formed between the plurality of organic layers 13 and the plurality of cathodes 14.

  The anode 12 is for applying an electric field to a target portion of the organic layer 13 together with the cathode 14, and is made of, for example, ITO. In the organic layer 13, a portion to which an electric field is applied by the anode 12 and the cathode 14 emits light by electroluminescence. As the organic layer 13, a red organic layer 13R, a green organic layer 13G, and a blue organic layer 13 are used. There is an organic layer 13B. Each of these organic layers 13R, 13G, and 13B has a light emitting layer (not shown) containing an organic phosphor. Each of the organic layers 13R, 13G, and 13B can be selected by selecting the type of the organic phosphor included in the light emitting layer. It emits green light and blue light. The cathode 14 is formed of aluminum or the like, for example, and reflects light generated in the organic layer 13 to the substrate 10 side. The light generated in the organic EL light emitting unit 11 passes through the substrate 10 and is emitted to the outside from the light emitting surface 10a on one side of the substrate 10.

  The substrate 10 serves as a base member for forming the plurality of organic EL light emitting units 11. However, in the present embodiment, the substrate 10 corresponds to an example of the light absorbing means of the present invention. The substrate 10 is configured using, for example, a transparent resin plate or glass plate, and first and second light absorbers that absorb light in a wavelength range to be described later are mixed and mixed therein. ing.

  The first light absorber is an intermediate between the peak wavelengths of the red light peak wavelength (for example, 620 nm) emitted from the red light emitting portion 11R and the green light peak wavelength (for example, 530 nm) emitted from the green light emitting portion 11G. It absorbs light in the wavelength region (the wavelength region indicated by S1 in FIG. 3), and has an absorption wavelength peak in the wavelength range of 550 to 600 nm. The second light absorber is an intermediate wavelength region (indicated by reference sign S2 in FIG. 3) between the peak wavelength of the green light described above and the peak wavelength of the blue light emitted from the blue light emitting unit 11B (for example, 470 nm). (Wavelength range shown) is absorbed, and has an absorption wavelength peak in the wavelength range of 490 to 515 nm. As these first and second light absorbers, for example, organic dye compounds are used. Some organic dye compounds have a characteristic of absorbing only light in a specific wavelength region in visible light. In this embodiment, two types of organic dye compounds having such characteristics are used. The first and second light absorbers are mixed in the raw material for forming the substrate 10 in advance, and the raw material is formed into a plate shape to produce the substrate 10 and dispersed therein. Has been.

  Next, the operation of the organic EL light emitting device A1 will be described.

  First, when an electric field is applied to each organic EL light emitting unit 11, red light, green light, and blue light are emitted and incident on the substrate 10. Here, the light incident on the substrate 10 has an emission spectrum as shown in FIG. 2A, for example, as described in the prior art. The emission spectrum when the red light emitting unit 11R, the green light emitting unit 11G, and the blue light emitting unit 11B are simultaneously driven is as shown in FIG. As can be understood from the drawing, the red light SR, the green light SG, and the blue light SB partially overlap with each other in the base region, and the light intensity of the overlapped portion is relatively high. The purity of is low.

  On the other hand, as described above, the substrate 10 is mixed with the first and second light absorbers and absorbs light in a predetermined wavelength range. More specifically, as shown in FIG. 3, the light emitted from the red light emitting unit 11R absorbs light in the skirt range shorter than the peak wavelength (620 nm). For the light emitted from the green light emitting unit 11G, the light in both the short wavelength side and the long wavelength side of the peak wavelength (530 nm) is absorbed, and the light emitted from the blue light emitting unit 11R is Light in the skirt range on the longer wavelength side than the peak wavelength (470 nm) is absorbed. For this reason, in the organic EL light emitting device A1, light with high purity of red, green, and blue having a small half width is emitted from the light emitting surface 10a of the substrate 10.

  In the present invention, the type of light absorber dispersed and mixed in the substrate may be appropriately selected according to the characteristics of light emitted from the organic EL light emitting device (for example, the type of organic phosphor). One of the first and second light absorbers can be omitted. In addition to the first and second absorbers, it absorbs light (eg, 640 nm or more) in the tail wavelength side longer than the peak wavelength of red light (620 nm), or more than the peak wavelength of blue light (470 nm) A light absorber that absorbs light in the skirt range on the short wavelength side (for example, 450 nm or less) may be additionally used.

  FIG. 4 shows another embodiment of the present invention. In FIG. 4 and subsequent figures, the same or similar elements as those of the above embodiment are denoted by the same reference numerals as those of the above embodiment.

  The organic EL light emitting device A2 shown in FIG. 4 has a configuration in which first and second light absorbing layers 21 and 22 as light absorbing means are stacked on the light emitting surface 10a of the substrate 10A. . The substrate 10A is formed using, for example, a transparent resin plate or glass plate, and no light absorber is mixed therein. The 1st light absorption layer 21 absorbs the light of the intermediate wavelength range of each peak wavelength of red light and green light, and the 2nd light absorption layer 22 is green light and blue light. It absorbs light in the intermediate wavelength region between the peak wavelengths. These first and second light absorption layers 21 and 22 are in the form of a film or a sheet in which the first and second light absorbers similar to those of the above-described embodiment are dispersed and mixed in the transparent base material. It is.

  In the organic EL light emitting device A2 of the present embodiment, when light emitted from the plurality of organic EL light emitting units 11 passes through the first and second light absorption layers 21 and 22, Light in the intermediate wavelength regions S1 and S2 shown in FIG. 3 is sequentially absorbed. As a result, the light finally obtained is light with high red, green, and blue purity, as in the previous embodiment shown in FIG.

  Note that the first and second light absorption layers 21 and 22 may be stacked on the substrate 10A in the order opposite to the stacking order shown in FIG. Moreover, it is also possible to omit one of the first and second light absorption layers 21 and 22. Furthermore, the light absorption layer can also be formed as a single layer in which both the first and second light absorbers are mixed in the same layer. In addition to the first and second light absorption layers 21 and 22, a third light absorption layer that absorbs light in a skirt range longer than the peak wavelength (620 nm) of red light (eg, 640 nm or more), and You may further form both or one of the 4th light absorption layers which absorb the light (for example, 450 nm or less) of the base wavelength side shorter than the peak wavelength (470 nm) of blue light. About a light absorption layer, it may replace with the means formed in a film form or a sheet form, and may comprise a film | membrane form by apply | coating and hardening the paste in which the light absorber was mixed directly to the board | substrate 10A.

  5 to 8 show an example in which the organic EL light emitting device according to the present invention is configured as an organic EL print head. The organic EL print head A3 of the present embodiment is for performing color printing on a photosensitive recording medium such as photosensitive paper K, and includes an organic EL print head substrate 31 and a lens array 32.

  The organic EL print head substrate 31 is for emitting line-shaped light toward the lens array 32. As shown in FIGS. 7 and 8, the organic EL print head substrate 31 has a substrate 10B and a plurality of organic EL light emitting sections 11, and the basic configuration thereof is shown in FIG. The same as the substrate 10 and the plurality of organic EL light emitting units 11. Therefore, the first and second light absorbing materials described above are dispersed and mixed in the substrate 10B. A sealing case 38 is provided on the substrate 10B to cover and protect the plurality of organic EL light emitting units 11.

  The substrate 10B has a long rectangular flat plate shape, and three rows of cathodes 14 and organic layers 13 are formed on the substrate 10B so as to extend in the longitudinal direction of the substrate 10B. On the other hand, the plurality of anodes 12 extend in the short direction of the substrate 10B. In the organic layer 13, a plurality of portions where the plurality of anodes 12 and the three rows of cathodes 14 intersect and are sandwiched therebetween are regions capable of emitting light, and this portion is the organic EL light emitting unit 11. Each of the plurality of red light emitting portions 11R, green light emitting portions 11G, and blue light emitting portions 11B is arranged in a line at regular intervals in the longitudinal direction of the substrate 10B. Terminal wiring portions 14 a are connected to the longitudinal ends of the three rows of cathodes 14. On the other hand, one end in the longitudinal direction of the plurality of anodes 12 extends toward the plurality of drive ICs 34 mounted on the substrate 10B, and is electrically connected to the plurality of drive ICs 34. By the switching operation of the plurality of drive ICs 34, energization is turned on / off, and light emission drive of the plurality of organic EL light emitting units 11 is controlled.

  As shown in FIGS. 6 and 7, the lens array 32 is for focusing the light emitted from each organic EL light emitting unit 11 on the photosensitive paper K (see FIG. 5), and is attached to the lens holder 32a. A plurality of rod lenses 32b are arranged and held in a row. Each lens array 32 can form an erecting equal-magnification image, for example. The lens array 32 is assembled to the organic EL print head substrate 31 so that the lens surfaces of the rod lenses 32b face the plurality of organic EL light emitting units 11 with the substrate 10B interposed therebetween.

  In the organic EL print head A3, red light, green light, and blue light are emitted from the organic EL print head substrate 31 in a line shape, and the line light is converged by the lens array 32 to be photosensitive paper. K is irradiated. On the other hand, the organic EL print head substrate 31 has a plurality of organic EL light emitting units 11 and a substrate 10B having the same configuration as the organic EL light emitting device A1 shown in FIG. For this reason, each of the line-shaped red light, green light, and blue light emitted from the organic EL print head substrate 31 and eventually the organic EL print head A3 has a small half-value width in the emission spectrum (see FIG. 3). ). As a result, a high-quality color image with good color reproducibility can be formed on the photosensitive paper K.

  FIG. 9 shows an example in which the organic EL display device according to the present invention is configured as an organic EL image display device. The organic EL display device A4 of the present embodiment is capable of displaying a color image and includes an organic EL light emitting panel 40.

  The organic EL light emitting panel 40 includes a plurality of organic EL light emitting units 11 arranged in a matrix on a substrate 10C. The basic configuration of the substrate 10C and the plurality of organic EL light emitting units 11 is the same as that shown in FIG. Therefore, the substrate 10C is also mixed with the light absorber and can absorb light in a predetermined frequency range. On this board | substrate 10C, the sealing case 43 which covers the some organic EL light emission part 11 and protects these is provided. In this organic EL light emitting panel 40, one image is composed of a total of three light emitting parts, that is, a red light emitting part 11R, a green light emitting part 11G, and a blue light emitting part 11B, which are adjacent to each other. A desired image can be displayed by emitting light and selecting the light emission intensity of these light emitting portions. A driving IC 34A electrically connected to the plurality of cathodes 14 is mounted on the substrate 10C, and the driving IC 34A plays a role of selectively driving the plurality of organic EL light emitting units 11 as described above.

  In the organic EL display device A4, red, green, and blue light is emitted in a planar shape from the organic EL light emitting panel 40, and this point is different from the organic EL print head A3 described above. However, when the light passes through the substrate 10C, the light in the intermediate wavelength region S1 of red light and green light and the light in the intermediate wavelength region S2 of green light and blue light are absorbed. By this action, the light transmitted through the substrate 10C has a small half width and high purity of red, green, and blue, so that a color image display with excellent image quality can be performed.

  Note that the organic EL print head A3 shown in FIGS. 5 to 8 and the organic EL display device A4 shown in FIG. 9 are the same as those described for the organic EL light emitting device A1 of the embodiment shown in FIG. Design changes are possible. Further, instead of the means for dispersing and mixing the light absorber into the substrates 10B and 10C, it is also possible to use a light absorbing means similar to that used in the organic EL light emitting device A2 shown in FIG.

  The present invention is not limited to an organic EL light emitting device that emits light of three colors of red, green, and blue, but also to an organic EL light emitting device that emits light of only two colors or light of only one color. It is possible to apply. For example, even when a monochrome print head or a monochrome image display device is configured, if the purity of light used for image formation is increased, the quality of the print image or display image can be improved.

It is principal part sectional drawing which shows an example of the basic structure of the organic electroluminescent light-emitting device which concerns on this invention. (A) is a graph which shows an example of the emission spectrum of the light which generate | occur | produces in an organic EL light emission part, (b) is a graph which shows the state which synthesize | combined the emission spectrum shown to (a). It is a graph which shows an example of the emission spectrum of the light finally obtained by the organic electroluminescent light emitting device shown in FIG. It is principal part sectional drawing which shows the other example of the basic structure of the organic electroluminescent light emitting device which concerns on this invention. It is a whole perspective view which shows an example at the time of applying this invention to an organic electroluminescent print head. FIG. 6 is an exploded perspective view of the organic EL print head shown in FIG. 5. It is VII-VII sectional drawing of FIG. It is a perspective view which shows the principal part of the organic electroluminescent print head board | substrate in the organic electroluminescent print head shown in FIG. It is a partially broken perspective view which shows an example at the time of applying this invention to an organic electroluminescence display.

Explanation of symbols

A1, A2 Organic EL light emitting device A3 Organic EL print head (organic EL light emitting device)
A4 Organic EL display device (organic EL light-emitting device)
10, 10A substrate (light absorption means)
DESCRIPTION OF SYMBOLS 11 Organic EL light emission part 11R Red light emission part 11G Green light emission part 11B Blue light emission part 21 1st light absorption layer (light absorption means)
22 2nd light absorption layer (light absorption means)

Claims (6)

An organic EL light emitting device having a red light emitting portion, a green light emitting portion, and a blue light emitting portion that individually emit red light, green light, and blue light as a plurality of organic EL light emitting portions,
Light that absorbs at least one of the light in the intermediate wavelength region of the red light and the green light and the light in the intermediate wavelength region of the green light and the blue light from the light generated in the plurality of organic EL light emitting units. An organic EL light emitting device comprising an absorbing means.   The light absorption means has a first light absorption band having an absorption wavelength peak in a wavelength range of 550 to 600 nm, and a second light absorption band having an absorption wavelength peak in a wavelength range of 490 to 515 nm. The organic EL light-emitting device according to claim 1. The plurality of organic EL light emitting units are formed on a substrate, and light emitted from the plurality of organic EL light emitting units is configured to pass through the substrate.
The organic EL light-emitting device according to claim 1, wherein the substrate is configured as the light absorbing means by dispersing a light absorber in the substrate. The plurality of organic EL light emitting units are formed on a substrate, and light emitted from the plurality of organic EL light emitting units is configured to pass through the substrate.
The organic EL light-emitting device according to claim 1, wherein the light absorbing means is provided on the light emitting surface of the substrate in a stacked manner.   5. The organic EL display head for forming an image by irradiating light onto a photosensitive recording medium, or an organic EL display device for displaying an image. 6. The organic EL light emitting device described. An organic EL light emitting device including an organic EL light emitting unit that emits red light, green light, or blue light,
An organic EL light emitting device comprising light absorbing means for absorbing light in a wavelength region in a skirt region different from a peak wavelength region of the light from light generated in the organic EL light emitting unit.

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