JP4369066B2 - Method for manufacturing organic electroluminescent display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic electroluminescent (hereinafter referred to as organic EL) display, and more particularly to a method for manufacturing an organic EL display capable of full color display and an organic EL display manufactured by the manufacturing method.
[0002]
[Prior art]
An organic EL element in which a light emitting layer is composed of an organic compound has attracted a great deal of attention as a display element that can be driven at a low voltage. Some organic EL elements use low molecular materials that are formed by vacuum deposition and others that use high molecular materials that are formed by coating. Particularly, those using high molecular materials do not require a vacuum process. It is highly expected from an industrial point of view.
[0003]
[Problems to be solved by the invention]
In order to manufacture a full-color display organic EL display, it is necessary to pattern the red, green, and blue organic EL elements and arrange them in a plane. In organic EL devices using low molecular weight materials, it is necessary to align the shadow mask during vacuum deposition. However, since alignment accuracy is limited, an ultrahigh-definition full-color organic EL display must be manufactured using this method. It is difficult.
[0004]
On the other hand, if the patterning of the organic EL element is performed by photolithography widely used in semiconductor manufacturing, the organic EL element is not resistant to the photolithography patterning process. It is very difficult to paint red, green and blue.
[0005]
For this reason, as a conventional method for patterning an organic EL element, an inkjet method (refer to Japanese Patent Laid-Open No. 10-12377), a photo bleaching method (Spring of 1997, 44th Applied Physics Related Conference Lecture Proceedings, 29p-NK-14, pp. 1156) and thermal diffusion method (Jpn. J. Appl. Phys. 38, (1999) pp. L1143-L1145).
[0006]
In the above, the ink jet method is a technique often used in a color printer or the like, but there is a problem that uneven luminance of pixels occurs due to variations in the amount of ink discharged from the nozzles. The photobleaching method uses the photo-oxidation effect of ultraviolet irradiation to change the emission color. By this method, a light emitting element that emits red, green, and blue light with high color purity for full colorization is used. It is extremely difficult to obtain.
[0007]
The thermal diffusion method is to adjust the emission color by adding a dye to a polymer by heat, but there is a bleeding of the dye caused by the diffusion of heat in a long heating time of about 1 minute 30 seconds. It is difficult to perform high-definition patterning by this method. Therefore, any of the conventional methods described above is difficult to produce a high-definition organic EL display having uniform brightness and excellent color purity using them.
[0008]
An object of the present invention is to provide an organic EL display manufacturing method and a manufacturing method thereof capable of manufacturing an ultra-high-definition full-color organic EL display by patterning red, green, and blue organic EL elements with high precision and planar arrangement. It is to provide an organic EL display manufactured by.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method of manufacturing an organic electroluminescent display according to the present invention includes: (a) a first medium in which a transparent electrode and a first host organic material are sequentially formed on a glass substrate or a plastic substrate. and generating, (b) the first protective layer on a substrate, a light absorber and a second protective layer sequentially deposited, further dye molar concentration of 50% or more to the second protective layer Generating a second medium on which the second host organic material added at a high concentration is formed, and (c) contacting the first host organic material and the second host organic material. (D) a step of disposing a photomask having a window of a predetermined size above the second medium; and (e) a laser beam in a visible range from above the photomask. Through the mask window Irradiating time about one second to the second medium Te, by temperature increase the light absorber, to disperse the dye is added to the second host organic material into the first host organic material and a step of doping Te, the laser light is visible light, the light absorber generates heat by absorbing the visible light, said photomask, said first protective layer to protect against the substrate In addition, with respect to the light absorber sandwiched by the second protective layer that protects against the second medium, a temperature rise area in a planar direction due to irradiation of the visible laser beam is limited. Is.
[0010]
In the method of manufacturing an organic electroluminescent display according to the present invention, the wavelength of the laser beam is 532 nm, and the light absorber is garnet oxide, ferrite, silicon (Si), or aluminum gallium arsenide (Al _x (Ga _{1 -x} As)) .
[0011]
In the method of manufacturing an organic electroluminescent display according to the present invention, the wavelength of the laser beam is 670 nm, and the light absorber is made of a rare earth-transition metal amorphous film or a noble metal / cobalt multilayer film / alloy. It is what.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on an embodiment of the invention with reference to the accompanying drawings.
FIG. 1 shows a first embodiment for producing an organic EL display by the method for producing an organic EL display according to the present invention.
In FIG. 1, first, a sputtering method is used on a glass substrate 1 to deposit and deposit an ITO transparent electrode 2 that becomes one electrode in the case of electroluminescence. Further, on the deposited ITO transparent electrode 2, As a host organic material (here, the host means that the organic material accepts a dye (guest) as described below), a high molecular weight polyvinyl carbazole (PVK) polymer 3 is applied by a spin coating method. The medium A is formed by forming a film (hereinafter, the formed film is referred to as a PVK film). The glass substrate 1 may be replaced with a plastic substrate. The glass substrate or plastic substrate is a surface plate of the display when the organic EL display is completed.
[0014]
Next, a silicon nitride (SiN) protective layer 5, a light absorber 6 composed of a dysprosium bismuth gallium iron garnet (DyBi ₂ GaFe ₄ O ₁₂ ) layer, and a SiN protective layer 7 are sequentially formed on the glass substrate 4 by sputtering. A host organic material (PVK polymer) 8 in which Nile red, which is a pigment that emits red light, is added at a high concentration of 50% or more in terms of molar concentration is formed on the uppermost SiN protective layer 7 by spin coating. To form a medium B.
[0015]
The media A and B produced as described above are arranged so that the PVK films 3 and 8 are in contact with each other, and a photomask 9 having a 0.5 mm square window is arranged above the medium B. Under such an arrangement, the second harmonic light (wavelength: 532 nm, wavelength: 532 nm, semiconductor-excited neodymium-doped yttrium vanadate (Nd: YVO ₄ ) laser generated by the laser source 10 from above the photomask 9. Intensity: 4 W), for example, is applied for 1 second to raise the temperature of the light absorber 6 and heat the PVK films 3 and 8, and the Nile Red added to the PVK film 8 of the medium B at a high concentration. The PVK film 3 of the medium A is doped. Note that the photomask 9 is for limiting the temperature rise area in the planar direction due to the laser beam irradiation of the light absorber 6.
[0016]
Further, in the laser light irradiation, as shown in FIG. 1, the beam diameter is slightly expanded using the spatial filter 11 and the plano-convex lens 12, and further, the laser light incident on the photomask 9 using the aperture 13 is irradiated. Shape the intensity distribution to be uniform.
In addition, depending on the size of the element to dope, said optical system, irradiation time, etc. can be changed and the temperature of a light absorber can be set arbitrarily.
[0017]
FIG. 2 shows the PVK film of the medium A manufactured in the first embodiment of the present invention, the PVK film itself prepared as the medium A before laser light irradiation, and the PVK film manufactured by the conventional spin coating method. The measurement results of the emission characteristics of the ultraviolet excitation are shown by curves (a), (b), and (c), respectively.
As shown by the curve (a) in FIG. 2, according to the present invention, the Nile Red-added PVK film obtained by doping (photodoping) Nile Red with a laser beam exhibits a red emission near 600 nm. Yes.
[0018]
In addition, as shown by curves (b) and (c) in FIG. 2, the PVK film of the medium A before doping with Nile red showed blue light emission around 410 nm, and the PVK and Nile red were dissolved in the solution. A film having a dye concentration of about 1% produced by a spin coating method (conventional method for producing a PVK film) exhibits red light emission in the vicinity of 600 nm, like the Nile red-added PVK film according to the present invention.
[0019]
From the above, the Nile Red-added PVK film obtained by doping Nile Red according to the present invention confirms that Nile Red is doped and dispersed in the PVK film. At this time, the doping concentration can be controlled by the laser power, the laser beam irradiation time, the dye concentration of the medium B, the composition of the light absorber of the medium B that determines the light absorption, the film thickness, and the like. After the above treatment, a metal electrode of an aluminum-lithium (Al-Li) alloy, which becomes the other electrode during electroluminescence, is vapor-deposited on the surface of the portion doped with Nile red to complete a red light-emitting organic EL display.
[0020]
The production of the red light-emitting organic EL display has been described above. However, it is assumed that the coumarin 6 is added at a high concentration by replacing the PVK film 8 (see FIG. 1) of the medium B with Nile red, and the added coumarin 6 is used. Is doped into the PVK film 3 of the medium A (see FIG. 1) to obtain a green light emitting organic EL display.
[0021]
Similarly, it is assumed that the PVK film 8 of the medium B (see FIG. 1) is replaced with Nile Red and tetraphenylbutadiene (TPB) is added at a high concentration, and the added TPB is used as the PVK film 3 of the medium A (see FIG. 1). 1)), an organic EL display emitting blue light is obtained.
[0022]
FIG. 3 shows the structure of an organic EL display capable of full color display manufactured in the first embodiment of the present invention.
In the organic EL display shown in FIG. 3, Nile Red, Coumarin 6 and the window corresponding to, for example, the left end, the second position from the left end, and the third position from the left end of the window of the photomask 9 shown in FIG. Each colorant of TPB is doped into the PVK film of medium A, and a metal electrode of an aluminum-lithium (Al-Li) alloy is deposited on the doped surface to complete a full color organic EL display. 3 respectively correspond to the glass substrate, ITO transparent electrode, and PVK film (polymer) in FIG.
[0023]
FIG. 4 shows an EL spectrum of the produced full-color organic EL display.
From the figure, it can be seen that the produced full-color organic EL display can emit red, green, and blue colors.
[0024]
As described above, according to the first embodiment of the present invention, when producing a full-color organic EL display, the high-concentration dye-added PVK polymer 8 of the medium B is replaced with one added with a different dye. By doping these pigments into the PVK film (PVK polymer) 3 of the medium A using light, it is possible to easily pattern red, green, and blue light emitting organic EL elements.
[0025]
In addition, according to the first embodiment of the present invention, the laser beam irradiation time is about 1 second, which is much longer than the heating time (about 1 minute 30 seconds) reported in the conventional thermal diffusion method. Therefore, the spread of the element area in the planar direction due to bleeding can be prevented, and thus a high-definition full-color organic EL display can be manufactured. Furthermore, there is an advantage that the chromaticity can be adjusted by changing the dye to be doped.
[0026]
As a modification of the first embodiment of the present invention, a garnet-based oxide or ferrite having a composition other than dysprosium bismuth gallium iron garnet is used as a light absorber for the medium B, and the semiconductor has a wavelength of 532 nm. Even when a laser is used, a display capable of displaying a high-definition image can be manufactured.
[0027]
Next, a second embodiment of the present invention will be described.
Here, with respect to the medium B of the first embodiment of the present invention described above, a rare earth element such as terbium iron cobalt (TbFeCo) or gadolinium iron cobalt (GdFeCo) is used as a light absorber (indicated by reference numeral 6 in FIG. 1). It is possible to dope light by using a semiconductor laser having an oscillation wavelength of 670 nm as a laser beam for raising the temperature of a single transition metal amorphous film.
[0028]
Next, a third embodiment of the present invention will be described.
Here, with respect to the medium B of the first embodiment of the present invention described above, platinum / cobalt (Pt / Co) or palladium / cobalt (Pd / Co) is used as a light absorber (indicated by reference numeral 6 in FIG. 1). It is possible to perform optical doping using a semiconductor laser having an oscillation wavelength of 670 nm as a laser beam for raising the temperature of a noble metal / Co multilayer film / alloy such as
Next, a fourth embodiment of the present invention will be described.
Here, with respect to the medium B of the first embodiment of the present invention described above, silicon (Si) or aluminum gallium arsenide (Al _x Ga _1-x ) is used as a light absorber (indicated by reference numeral 6 in FIG. 1). It is possible to dope light by using a semiconductor material such as As) and using a semiconductor laser having an oscillation wavelength of 532 nm as a laser beam for raising the temperature of the semiconductor material.
[0030]
In each of the low molecular weight organic EL elements that form a film by a dry process in a vacuum chamber using each of the light absorbers (indicated by reference numeral 6 in FIG. 1) used in the first to fourth embodiments described above, Patterning can be performed using a light doping method. This will be described as a fifth embodiment of the present invention.
In this embodiment, a medium A is produced by forming a film of triphenylamine derivative (TPD), which is a hole transporting material, on the glass substrate with ITO 2, 1 (see FIG. 1) by vacuum deposition. Further, a light absorber 6 (see FIG. 1) in which a tris (8-quinolinolato) aluminum (III) complex (Alq) added with Nile red as a pigment at a high concentration is sandwiched between SiN protective layers 5 and 7 (see FIG. 1). The medium B is produced by vacuum deposition on the top.
[0031]
Next, the film surfaces of the medium A and the medium B are brought into contact with each other in a vacuum, Nile red doping is performed from the film surface of the medium B to the film surface of the medium A, and the doped medium A is an Alq serving as an electron transport layer. Is formed by vacuum vapor deposition, and a metal electrode of an aluminum-lithium (Al-Li) alloy is vapor-deposited to produce a red light emitting EL element. Similarly, blue and green light-emitting organic EL elements can be produced by this method. Therefore, according to this embodiment (fifth embodiment), even for a low molecular weight organic EL element, It is possible to pattern with high definition.
[0032]
Finally, when the dye is doped with laser light, a glass substrate (corresponding to the glass substrate 4 in FIG. 1) having grooves formed on the surface is used as the medium B, and a photomask is not used. An embodiment for manufacturing an organic EL display will be described as a sixth embodiment of the present invention.
FIG. 5 shows a method for manufacturing the organic EL display according to the present embodiment.
[0033]
In FIG. 5, a light absorber layer 16 sandwiched between protective layers 15 and 17 is formed on a glass substrate 14 having grooves formed in a concavo-convex shape by a sputtering method, and a dye such as Nile Red is further formed thereon. The PVK 18 added to the concentration is formed using a spin coater or vacuum vapor deposition means, thereby producing a medium B in which the formed film surface is uneven according to the unevenness of the glass substrate 14.
[0034]
Thereafter, the same medium A as shown in FIG. 1 is used, and the film surfaces of these two media are brought into contact with each other to perform photodoping of the dye. In this case, since only the film surface corresponding to the convex part of the glass substrate is in contact, it is obvious that the light dope is not performed on the non-contact part, and therefore the photomask 9 shown in FIG. 1 is unnecessary.
Also according to the present embodiment, high-definition patterning is possible as in the first to fifth embodiments described above.
[0035]
【The invention's effect】
By using the organic EL display manufacturing method according to the present invention to produce organic EL elements that emit red, green, and blue light, high-precision patterning is possible. Accordingly, the manufacturing method of the present invention is an organic EL capable of full color display. Particularly suitable for manufacturing displays.
In addition, the organic EL display manufactured by the manufacturing method of the present invention can display an extremely high-definition image without color blur.
[Brief description of the drawings]
FIG. 1 shows a first embodiment in which an organic EL display is manufactured by an organic EL display manufacturing method according to the present invention.
FIG. 2 shows a PVK film of medium A manufactured in the first embodiment of the present invention, a PVK film itself prepared as laser medium before laser light irradiation, and a PVK film manufactured by a conventional spin coating method. The measurement results of the emission characteristics of the ultraviolet excitation are shown by curves (a), (b), and (c), respectively.
FIG. 3 shows the structure of an organic EL display capable of full color display manufactured in the first embodiment of the present invention.
FIG. 4 shows an EL spectrum of the produced full-color organic EL display.
FIG. 5 shows a method for manufacturing an organic EL display according to a sixth embodiment of the present invention.
[Explanation of symbols]
1, 4 glass substrate 2 ITO transparent electrode 3 Polyvinylcarbazole (PVK)
5,7 SiN protective layer 6 Light absorber 8 PVK with high concentration of Nile Red
9 Photomask 10 Laser source 11 Spatial filter 12 Plano-convex lens 13 Aperture 14 Glass substrate 15, 17 Protective layer 16 Light absorber layer 18 PVK with a high concentration of dye added

Claims (3)

A method for producing an organic electroluminescent display comprising:
(A) generating a first medium in which a transparent electrode and a first host organic material are sequentially formed on a glass substrate or a plastic substrate;
(B) a first protective layer on the substrate, the light absorbing material and sequentially forming a second protective layer, further adding to the high concentration of 50% or more of the dye at a molar concentration on the second protective layer Generating a second medium on which the second host organic material is deposited;
(C) disposing the first host organic material and the second host organic material in contact with each other;
(D) disposing a photomask having a window of a predetermined size above the second medium;
(E) The second medium is irradiated with laser light in the visible range from above the photomask through the window of the photomask for about 1 second to raise the temperature of the light absorber, thereby And dispersing the pigment added to the host organic material in the first host organic material,
The laser light is visible light, the light absorber generates heat by absorbing the visible light,
The photomask includes the first protective layer protecting the substrate and the light absorber sandwiched by the second protective layer protecting the second medium, in the visible region. A method for manufacturing an organic electroluminescent display, characterized by limiting a temperature rise area in a planar direction by laser light irradiation . The wavelength of the laser beam is 532 nm, and the light absorber is made of garnet-based oxide, ferrite, silicon (Si), or aluminum gallium arsenide (Al _x Ga _1-x As). 2. A method for producing an organic electroluminescent display according to 1.   2. The organic electroluminescent display according to claim 1, wherein the wavelength of the laser beam is 670 nm, and the light absorber is made of a rare earth-transition metal amorphous film or a noble metal / cobalt multilayer film / alloy. Production method.

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