Abstract:
A luminescence device is formed of a substrate, and a laminated layer structure formed on the substrate including a plurality of luminescence layers emitting different luminescence colors, and a plurality of electrodes forming pairs of electrodes each sandwiching an associated luminescence layer. At least one of the plurality of electrodes are provided with apertures, through which a luminescence flux emitted from at least one of the luminescence layers is transmitted. As a result, the luminescence device can emit different luminescence colors expected to cause color mixing with each other with a minimum of positional difference leading to color irregularity.

Description:
FIELD OF THE INVENTION AND RELATED ART 
     The present invention relates to an (electro-)luminescence device utilized in copying machines, printers and display apparatus, e.g., as a backlight device for a display apparatus and a light source for illuminating an original in an image-reading apparatus. 
     Hitherto, as light-emission devices for converting applied electricity into light, there have been used, e.g., tubes and bulbs, such as incandescent lamps utilizing light emission caused by resistance heating and fluorescent tubes utilizing light emission caused by discharge in dilute gas, and semiconductor devices, such as light-emitting diodes (LED) utilizing light-emission caused by recombination of electrons and holes at pn-junctions formed in organic crystals. As indoor or outdoor illumination light sources, the tubes and bulbs have been most frequently used, but LEDs have been frequently used as indicators for various electronic appliances. Furthermore, recently, liquid crystal display apparatus equipped with fluorescent lamps as a backlight have been used as a display device for computers and portable display terminals. In addition to such usages directly exposed to human eyes, there have been frequently used functional devices, such as light sources for illuminating originals in image reading apparatus for facsimile apparatus and image scanners, and photo-writing heads in LED printers. 
     These light source devices have their own advantages and disadvantageous depending on their types. For example, the tubes and bulbs are suitable for emitting intense light by receiving a large electric power but are large in size and liable to be broken. Further, they are not suitable for usages requiring a high-speed responsiveness. On the other hand, LEDs can emit only relatively weak light but are advantageous in that they are small in size, have excellent reliability and have high-speed responsiveness. 
     While not being as popular as the above-mentioned light sources, there has been partially used an electroluminescence device wherein a thin film layer comprising a crystalline fluorescent substance is formed on a substrate by coating or vapor deposition and is supplied with an AC electric field via an insulating layer to cause luminescence. Such an electroluminescence device can be formed in a thin film on a substrate and is advantageous for usages for uniformly illuminating wide ranges or for providing a small-sized, particularly a thin, apparatus including a light source. 
     However, such an electroluminescence device has drawbacks that it can only emit weak light even lower than an LED and requires a difficult drive scheme requiring a relatively high AC voltage, so that it has not been a popular light source device. 
     On the other hand, in recent years, there has been developed an organic film luminescence device (also called an organic LED device), which is provided in a film on a substrate, provides high luminance and allows a DC drive. 
     FIG. 11 illustrates a representative organization (laminar structure) of such an organic LED device. 
     Referring to FIG. 11, an organic LED device includes a substrate  1100 , an anode  1201  comprising a transparent electrode of indium tin oxide (ITO), a hole-transporting layer  1202  comprising an organic hole-transporting material, such as an organic diamine (of, e.g., formula (1) below), an electron-transporting layer  1203  comprising an organic electron-transporting material, such as tris(8-quinolinolato)aluminum (of formula (2) below) and a cathode  1204  of a substance having a low work function such as Al and/or Hg—Ag alloy, laminated in this order.                           
     When a voltage is applied between the anode  1201  and the cathode  1204 , holes injected from the anode  1202  to the hole-transporting layer  1202  and electrons injected from the cathode  1204  to the electron-transporting layer, are re-combined to cause luminescence. 
     FIG. 12 illustrates a state of luminescence occurring in the organic LED device of FIG.  11 . 
     Referring to FIG. 12, a portion denoted by  A   schematically represents the luminescence caused by recombination of holes injected to the hole-transporting layer  1202  from the anode  1201  and electrons injected to the electron-transporting layer  1203  from the cathode  1204 . 
     Such organic LED devices can emit various colors of luminescence, e.g., by using different organic materials for the hole-transporting layer  1202  or the electron-transporting layer  1203 , by admixing another organic material into these layers, or by inserting a luminescence layer comprising another organic material between these layers. 
     However, according to a conventional organic LED device, the luminescence color is determined by organic materials constituting a luminescence part, so that pixels of respectively different luminescence colors have to be formed in a usage, like a full-color display, requiring independent control of different luminescence colors. 
     FIG. 13 illustrates a typical organization of such an organic LED device. 
     Referring to FIG. 13, the organic LED device includes a substrate  1100 ; a first pixel comprising an anode (portion)  1201  comprising ITO for the first pixel, a hole-transporting layer (portion)  1202  of an aromatic diamine (of formula (1)), an electron-transporting layer/luminescence layer  1203  of tris(8-quinolinolato)aluminum (of formula (2)) and a cathode  1204  of Al or Hg—Ag alloy, etc.; and also a second pixel comprising an anode (portion)  1401  comprising ITO, a hole-transporting layer (portion)  1202  of an aromatic diamine (of formula (1)), an electron-transporting layer/luminescence layer  1203  of a mixture of tris(8-quinolinolato)aluminum complex (of formula (2)) and a fluorescent substance (of formula (3) below), and a cathode  1404  of Al or Mg—Ag alloy.                           
     In the above-mentioned device, the first pixel emits green luminescence, and the second pixel emits red luminescence. 
     In the device, the respective luminescence layers  1203 ,  1403  and the respective cathodes  1204 ,  1404 , have to be patterned into shapes of the respective pixels. Moreover, if the cathodes  1204  and  1404  of the adjacent pixels directly contact each other, or even in a single pixel, if the cathode  1204  ( 1404 ) directly contacts the anode  1202  ( 1401 ) or the hole-transporting layer  1202  ( 1402 ), phenomena, such as crosstalk and current leakage, undesirable for the device performances, are liable to occur, so that the mutually adjacent pixels have to be formed in sufficient separation from each other. 
     In this case, as different luminscence colors are emitted from different pixels, different color pixels are liable to be noticeable to human eyes by a careful observation, thus providing an unsatisfactory display quality. 
     When such an organic LED device is used as a light source for illuminating an original in an image reading apparatus, the directively of illumination light reaching a certain point on the original can be different for respective luminescence colors due to the fact that different luminescence colors are emitted from fairly separated different pixels, so that color irregularity is liable to occur depending on the surface gloss of the original. 
     SUMMARY OF THE INVENTION 
     In view of the above-mentioned problems of the prior art, a principal object of the present invention is to provide a luminescence device, particularly an organic LED device, having a minimized difference in sites for emitting different luminescence colors. 
     According to the present invention, there is provided, a luminescence device, comprising a substrate, and a laminated layer structure formed on the substrate including a plurality of luminescence layers emitting different luminescence colors, and a plurality of electrodes forming at least one pair of electrodes each sandwiching an associated luminescence layer, wherein at least one of the plurality of electrodes is provided with apertures, through which a luminescence flux emitted from at least one of the luminescence layers is caused to pass. 
     Each of the plurality of luminescence layers may comprise one or more organic compound layers. In the luminescence device, plural layers of electrodes each belonging to different pairs of electrodes sandwiching associated luminescence layers of different luminescence colors are respectively provided with apertures of which positions and/or sizes may be at least partially different from each other. Further, each pair of electrodes sandwiching an associated luminescence layer may comprise one transparent electrode on a side closer to the substrate and the other opaque electrode provided with apertures on a side more remote from the substrate, so that the luminescence flux is emitted through the substrate. 
     Further, at least: one luminescence layer may be sandwiched by a pair of electrodes which are both provided with apertures of which positions and/or sizes are at least partially different from each other so that the pair of electrodes comprises one transparent electrode on a side closer to the substrate and the other opaque electrode, and luminescence light flux is emitted in a direction leaving away from the substrate. 
     The present invention further provides an image-reading apparatus including a luminescence device as described above as an illumination light source, and a data processing apparatus including such an image-reading apparatus as a data-reading unit. 
     The present invention further provides a display apparatus including a luminescence device as described above as a display unit. 
     These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1,  3  and  5  are schematic sectional views showing organization of organic LED devices according to a first, a second and a third embodiment, respectively, of the invention. 
     FIGS. 2,  4  and  6  are schematic sectional views illustrating luminescence states in the organic LED devices of FIGS. 1,  3  and  5 , respectively. 
     FIG. 7 is a partial perspective of an image-reading apparatus including an organic LED device of the second embodiment (FIG. 3) as a light source for illuminating an original. 
     FIG. 8 is a plan view of the organic LED device of FIG. 7 as viewed from the glass substrate side thereof. 
     FIG. 9 is an enlarged view of a part D shown in FIG.  8 . 
     FIG. 10 is an illustration of a facsimile apparatus including the image-reading apparatus of FIG.  7 . 
     FIG. 11 is a schematic sectional view showing a typical organization of a conventional organic LED device. 
     FIG. 12 is a schematic sectional view illustrating a luminescence state in the organic LED device of FIG.  11 . 
     FIG. 13 is a schematic sectional view showing a typical organization of a conventional organic LED including separate pixels of mutually different luminescence colors. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a laminar organization of an organic LED device according to a first embodiment of the present invention. 
     Referring to FIG. 1, the organic LED device includes a substrate  100 ; 
     a first anode  201  comprising a transparent electrode of ITO (indium tin oxide); a hole-transporting layer  202  comprising an aromatic diamine (of formula (1) above); an electron-transporting layer/luminescence layer  203  comprising tris(8-quinolinolato)aluminum complex (of formula (2) above); a first cathode  204  comprising a material having a low work function, such as Al or Mg—Ag alloy and provided with apertures  205  formed therein; 
     a transparent insulating layer  300  comprising, e.g., SiN or SiO 2 ; 
     a second anode  401  comprising a transparent electrode of ITO; a hole-transporting layer  402  comprising an aromatic diamine (of formula (1)); an electron-transporting layer/luminescence layer  403  comprising tris(8-quinolinolato)aluminum complex (of formula (2)) and a fluorescent substance (of formula (3) above); and a second cathode  404  comprising a material having a low work function such as Al or Mg—Ag alloy and provided with apertures  405 . 
     FIG. 2 schematically illustrates a state of luminescence occurring in the organic LED device of FIG.  1 . 
     Referring to FIG. 2, each portion A represents luminescence caused by recombination of holes injected to the hole-transporting layer  202  from the first anode  201  and electrons injected to the electron-transporting layer  203  from the first anode  204 . In this instance, green luminescence inherent to tris(8-quinolinolato)aluminum complex of formula (2) constituting the electron-transporting layer/luminescence layer  203  is emitted. The first cathode  204  is provided with the apertures  205  so that the luminescence is not caused at parts corresponding to the apertures  205 . 
     Referring further to FIG. 2, each portion B represents luminescence caused by recombination of holes injected to the hole-transporting layer  402  from the second anode  401  and electrons injected to the electron-transporting layer  403  from the second anode  404 . In this instance, rather than green luminescence inherent to tris(8-quinolinolato)aluminum complex constituting the electron-transporting layer/luminescence layer  403 , red luminescence attributable to the fluorescent substance (of formula (3)) added thereto as a dopant is predominant. The second cathode  404  is provided with the apertures  405  so that the luminescence is not caused at parts corresponding to the apertures  405 . 
     The red luminescence flux occurring at the portion B is transmitted through the apertures  205  formed in the first cathode  204  and emitted together with the green luminescence flux occurring at the portions A through the substrate  100 . 
     Accordingly, in this embodiment, pixels of different luminescence colors need not be formed at (horizontally) different positions, but different luminescence colors can be emitted from a horizontally single pixel. As a result, by sufficiently reducing the sizes of the apertures  205  and  405 , it is possible to provide an organic LED device from which different luminescence colors can be emitted from luminescence positions which are substantially free from local deviation (with a minimized positional deviation) relative to a pixel size. 
     Regarding the respective luminescence colors, the green luminescence is caused by a voltage applied between the first anode  201  and the first cathode  204 , and the red luminescence is caused by a voltage applied between the second anode  401  and the second cathode  404 , so that the respective luminescence colors can be independently emitted, thus allowing at least three color luminescences of green, red and orange (as mixture of green and red) to be issued from a substantially single pixel. 
     While the perspective layers and pixels may be designed in various manners, a specific example of the device of the above embodiment may be organized in the following dimensions: 
     (Respective Layer Thickness) 
     Anode ( 201 ,  401 ): 1200 Å 
     Hole-transporting layer ( 202 ,  402 ): 500 Å 
     Electron-transporting layer ( 203 ,  403 ): 500 Å 
     Cathode ( 204 ,  404 ): 2000 Å 
     Transparent insulating layer ( 300 ): 2000 Å 
     (Planar Sizes) 
     Pixel: 300 μm×300 μm 
     Aperture ( 205 ,  405 ): 50 μm×300 μm 
     (Operation Voltage) 
     10 volts between each pair of an anode and a cathode. 
     FIG. 3 illustrated a laminar organization of an organic LED device according to a second embodiment of the present invention. 
     Referring to FIG. 3, the organic LED device includes a substrate  100 ; 
     a first anode  201  comprising a transparent electrode of ITO (indium tin oxide); a hole-transporting layer  202  comprising an aromatic diamine (of formula (1) above); an electron-transporting layer/luminescence layer  203  comprising tris(8-quinolinolato)aluminum complex (of formula (2) above); a first cathode  204  comprising a material having a low work function, such as Al or Mg—Ag alloy and provided with apertures  205  formed therein; 
     a transparent insulating layer  300  comprising, e.g., SiN or SiO 2 ; 
     a second anode  401  comprising a transparent electrode of ITO; a hole-transporting layer  402  comprising an aromatic diamine (of formula (1)); an electron-transporting layer/luminescence layer  403  comprising tris(8-quinolinolato)aluminum complex (of formula (2)) and a fluorescent substance (of formula (3) above); and a second cathode  404  comprising a material having a low work function such as Al or Mg—Ag alloy and provided with apertures  405 ; 
     a transparent insulating layer  500  comprising, e.g., SiN or SiO 2 ; 
     a third anode  601  comprising a transparent electrode of ITO; a hole-transporting layer  602  comprising an aromatic diamine (of formula (1)); an electron-transporting layer/luminescence layer  603  comprising tris(8-quinolinolato)aluminum complex (of formula (2)) and a distyryl derivative (of formula (4) below); and a third cathode  604  comprising a material having a low work function such as Al or Mg—Ag alloy and provided with apertures  605 .                           
     FIG. 4 schematically illustrates a state of luminescence occurring in the organic LED device of FIG.  3 . 
     Referring to FIG. 4, each portion A represents luminescence caused by recombination of holes injected to the hole-transporting layer  202  from the first anode  201  and electrons injected to the electron-transporting layer  203  from the first anode  204 . In this instance, green luminescence inherent to tris(8-quinolinolato)aluminum complex of formula (2)) constituting the electron-transporting layer/luminescence layer  203  is emitted. The first cathode  204  is provided with the apertures  205  so that the luminescence is not caused at parts corresponding to the apertures  205 . 
     Referring further to FIG. 4, each portion B represents luminescence caused by recombination of holes injected to the hole-transporting layer  402  from the second anode  401  and electrons injected to the electron-transporting layer  403  from the second anode  404 . In this instance, rather than green luminescence inherent to tris(8-quinolinolato)aluminum complex constituting the electron-transporting layer/luminescence layer  403 , red luminescence attributable to the fluorescent substance (of formula (3)) added thereto as a dopant is predominant. The second cathode  404  is provided with the apertures  405  so that the luminescence is not caused at parts corresponding to the apertures  405 . 
     Further referring to FIG. 4, each portion C represents luminescence caused by recombination of holes injected to the hole-transporting layer  602  from the third anode  601  and electrons injected to the electron-transporting layer  603  from the third anode  604 . In this instance, blue luminescence attributable to the distyryl derivative (of formula (4)) added to tris(8-quinolinolato)aluminum complex as a dopant is predominant. The third cathode  604  is provided with the apertures  605  so that the luminescence is not caused at parts corresponding to the apertures  605 . 
     The red and blue luminescence fluxes occurring at the portion B and C are transmitted through the apertures  205  formed in the first cathode  204  and emitted together with the green luminescence flux occurring at the portions A through the substrate  100 . 
     Accordingly, in this embodiment, the different luminescence colors of R, G and B can be emitted from a horizontally single pixel. As a result, by sufficiently reducing the sizes of the apertures  205 ,  405  and  605 , it is possible to provide an organic LED device from which different luminescence colors can be emitted with substantially no local deviation relative to a pixel size. 
     Regarding the respective luminescence colors, the green luminescence is caused by a voltage applied between the first anode  201  and the first cathode  204 , the red luminescence is caused by a voltage applied between the second anode  401  and the second cathode  404 , and the blue color is caused by a voltage applied between the third mode  601  and the third cathode  604 , so that the respective luminescence colors can be independently emitted. 
     FIG. 5 illustrates a laminar organization of an organic LED device according to a third embodiment of the present invention. 
     Referring to FIG. 5, the organic LED device includes a substrate  100 ; 
     a first anode  201  comprising a transparent electrode of ITO (indium tin oxide) provided with apertures  206 ; a hole-transporting layer  202  comprising an aromatic diamine (of formula (1) above); an electron-transporting layer/luminescence layer  203  comprising tris(8-quinolinolato)aluminum complex (of formula (2) above); a first cathode  204  comprising a material having a low work function, such as Al or Mg—Ag alloy and provided with apertures  205  formed therein; 
     a transparent insulating layer  300  comprising, e.g., SiN or SiO 2 ; 
     a second anode  401  comprising a transparent electrode of ITO; a hole-transporting layer  402  comprising an aromatic diamine (of formula (1)); an electron-transporting layer/luminescence layer  403  comprising tris(8-quinolinolato)aluminum complex (of formula (2)) and a fluorescent substance (of formula (3) above); and a second cathode  404  comprising a material having a low work function such as Al or Mg—Ag alloy and provided with apertures  405 ; 
     a transparent insulating layer  500  comprising, e.g., SiN or SiO 2 ; 
     a third anode  601  comprising a transparent electrode of ITO; a hole-transporting layer  602  comprising an aromatic diamine (of formula (1)); an electron-transporting layer/luminescence layer  603  comprising tris(8-quinolinolato)aluminum complex (of formula (2)) and a distyryl derivative (of formula (4) above); and a third cathode  604  comprising a material having a low work function such as Al or Mg—Ag alloy and provided with apertures  605 . 
     FIG. 6 schematically illustrates a state of luminescence occurring in the organic LED device of FIG.  5 . 
     Referring to FIG. 6, each portion A represents luminescence caused by recombination of holes injected to the hole-transporting layer  202  from the first anode  201  and electrons injected to the electron-transporting layer  203  from the first anode  204 . In this instance, green luminescence inherent to tris(8-quinolinolato)aluminum complex of formula (2) constituting the electron-transporting layer/luminescence layer  203  is emitted. The first anode  201  is provided with apertures  206 , the first cathode  204  is provided with apertures  205 , and the apertures  206  and  205  are formed at mutually slightly deviated positions, so that the luminescence occurs at positions corresponding to edges of the apertures  205  and  206 . 
     Referring further to FIG. 6, each portion B represents luminescence caused by recombination of holes injected to the hole-transporting layer  402  from the second anode  401  and electrons injected to the electron-transporting layer  403  from the second anode  404 . In this instance, rather than green luminescence inherent to tris(8-quinolinolato)aluminum complex constituting the electron-transporting layer/luminescence layer  403 , red luminescence attributable to the fluorescent substance (of formula (3)) added thereto as a dopant is predominant. The second anode  401  is provided with apertures  406 , the second cathode  404  is provided with apertures  405 , and the apertures  406  and  405  are formed at mutually slightly deviated positions, so that the luminescence occurs at positions corresponding to edges of the apertures  405  and  406 . 
     Further referring to FIG. 6, each portion C represents luminescence caused by recombination of holes injected to the hole-transporting layer  602  from the third anode  601  and electrons injected to the electron-transporting layer  603  from the third anode  604 . In this instance, blue luminescence attributable to the distyryl derivative (of formula (4)) added to tris(8-quinolinolato)aluminum complex as a dopant is predominant. The third anode  601  is provided with apertures  606 , the third cathode  604  is provided with apertures  605 , and the apertures  606  and  605  are formed at mutually slightly deviated positions, so that the luminescence occurs at positions corresponding to edges of the apertures  605  and  606 . 
     The portions A, B and C causing luminescence are disposed at edges of the apertures, so that the respectively generated luminescence fluxes at A, B and C are emitted through the apertures  205  of the first cathode  204 , the apertures  405  of the second  404  and the apertures  605  of the third cathode  604  to be emitted to a side opposite to the substrate  100 . 
     Accordingly, in this embodiment, the different luminescence colors of R, G and B can be emitted from a horizontally single pixel. As a result, by sufficiently reducing the sizes of the apertures  205 ,  405  and  605 , it is possible to provide an organic LED device from which different luminescence colors can be emitted with substantially no local deviation relative to a pixel size. 
     Regarding the respective luminescence colors, the green luminescence is caused by a voltage applied between the first anode  201  and the first cathode  204 , the red luminescence is caused by a voltage applied between the second anode  401  and the second cathode  404 , and the blue color is caused by a voltage applied between the third mode  601  and the third cathode  604 , so that the respective luminescence colors can be independently emitted. 
     FIG. 7 illustrates a part of an image-reading apparatus  8  adopting the organic LED device shown in FIG. 3 according to the second embodiment of the present invention as a light source for illuminating an original. 
     Referring to FIG. 7, the image-reading apparatus  8  includes an organic LED device  1  as described above, a rod lens array  2 , a photoconverter element array  3 , a circuit substrate  4 , a housing  5  and a glass sheet  6  supporting an original  7 . 
     Light flux emitted from the organic LED device  1  supported in the housing  5  is transmitted through the glass sheet  6  to illuminate a surface of the original  7  supported thereon. Light flux reflected at the original  7  is passed through the rod lens array  2  to be focused at the photoconverter element array  3  mounted on the circuit substrate  4 . As a result, image data on the original  7  surface is read out by conversion into electric signals. 
     The image reading apparatus  8  thus comprising the organic LED device  1 , the rod lens array  2 , the photoelectric converter element array  3 , the circuit substrate  4  and the housing  5  is disposed to extend in a direction parallel to a side of the original supporting glass sheet  6  and is moved in an indicated arrow direction perpendicular to the extension direction thereof, so that images are read in a rectangular region determined by the length and the movement distance of the image reader  8 . 
     FIG. 8 shows a plan view of the organic LED device  1  in FIG. 7 as viewed from the side of the glass sheet  6  in FIG.  7 . 
     Referring to FIG. 8, the organic LED device ( 1 ) includes a transparent substrate  100  of, e.g., glass or plastic sheet, a light-emitting unit  101  as observed through the transparent substrate  100  and a flexible circuit sheet  102 . The anode, the cathode and the organic layer constituting the light-emitting unit  101  are disposed on a back of the substrate  100 . 
     FIG. 9 is an enlarged view of a section D shown in FIG. 8 showing the organization of the light-emitting unit  101  as observed through the transparent substrate  100 . More specifically, regarding the organization of the light-emitting unit ( 101  in FIG. 8) formed on the transparent substrate  100 , FIG. 9 shows a first anode  201  (of the organic LED device shown in FIG. 3) comprising a transparent electrode of ITO, a first cathode  204  comprising a conductor having a low work function such as Al or Mg—Ag alloy provided with apertures  205 , a second cathode  404 , and a third cathode  604 . The respective electrodes are connected to the flexible circuit sheet  102 . 
     Luminescence emitted from the third and second luminescence layers ( 603  and  403  in FIG. 3) are transmitted through the apertures  205  and emitted for illuminating the original surface together with the luminescence emitted from the first luminescence layer ( 203  in FIG.  3 ). 
     According to the above-mentioned image-reading apparatus, the positions of luminescence of different colors are substantially free from positional deviation, so that the directionality of illumination light reaching a certain point on the original is not different depending on different luminescence colors, so that the liability of color irregularity due to surface gloss of the original is deviated, thus allowing high-quality reading. 
     FIG. 10 is a side sectional view of a facsimile apparatus as a data processing apparatus including the image-reading apparatus of FIG. 7, which allows high-quality data processing through high-quality image reading owing to the use of an image-reading apparatus according to the present invention. Referring to FIG. 10, the facsimile apparatus incudes an image-reading apparatus  8 , a recording head  11 , a power supply unit  12 , a system control board  13 , a recording medium roll  14  from which a recording medium  14   a  is supplied via a platen roller  14   b  so as to allow recording by the recording head  11 , a feed roller  15  for feeding an original  7  via a separation claw  16  and a platen roller  17 , and an operation panel  18 . 
     The image reading apparatus according to the present invention is applicable not only to such a facsimile apparatus but also to various data processing apparatus, such as a scanner apparatus, utilizing a function of converting optical data into electric signals. 
     The organic LED device according to the present invention can also be used to constitute a (color) display apparatus allowing a high-quality display free from recognition of color points.