JP2005056855A - Electroluminescent element and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing technology for forming a fluorescent converting film without using a lithography process in a manufacturing method for an electroluminescent element. <P>SOLUTION: The method comprises a process of forming a partition member 20 having an opening corresponding to a pixel area on a substrate 10; a process of discharging fluorescent converting film precursors 40a, 40b, 40c into the opening by using a liquid droplet discharging head 2; and a process of solidifying the precursors 40a, 40b, 40c discharged onto the substrate 10 to form fluorescent converting films 40A, 40B, 40C. According to this method, the precursors 40a, 40b, 40c can be discharged while appropriately adjusting doping ratios of color conversion components of the precursors 40a, 40b, 40c on the spot and the color adjustment of the fluorescent converting film 40A, 40B, 40C is facilitated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an electroluminescence (EL) element. In particular, the present invention relates to a manufacturing technique of the element including a step of forming a fluorescence conversion film (CCM: color change media) without using a lithography process.

  The EL element includes an organic EL element and an inorganic EL element. The organic EL element is a self-luminous element that emits light by electrically exciting a fluorescent organic compound. This device is an all-solid-state device that emits light when applied with a low voltage of several volts, with high brightness, high-speed response, high viewing angle, surface emission, thin and capable of multicolor emission, and has characteristics at low temperatures. It has the feature that there is little change. An EL element using an organic substance as a light emitting material has a structure in which a light emitting layer and a fluorescence conversion film are combined, and the entire visible range can be easily covered by selecting the material of the light emitting layer and the fluorescence conversion film. Application to is actively performed. In particular, as a method for full colorization of such EL elements, for example, a method of converting white light emission into fluorescence (white light emission / fluorescence conversion method), a method of converting blue light emission into fluorescence (blue light emission / fluorescence conversion method), etc. It has been known.

  However, when a structure employing a white light emission / fluorescence conversion method, a blue light emission / fluorescence conversion method, or the like for full colorization of an EL element is manufactured, conventionally, a fluorescence conversion film is formed to correspond to a pixel region. The shape was patterned through a lithography process. Thus, when a fluorescence conversion film is formed on a substrate using a lithography process, the fluorescence conversion film material is wasted and the manufacturing cost is increased. Further, since the fluorescence conversion film material needs photosensitivity, the selection range of the material is narrowed. Furthermore, there is a problem that the running cost of equipment required for the lithography process is high and the equipment space is widened.

Since EL devices are expected to be applied to future full-color flat panel displays, reduction of manufacturing costs is an indispensable issue.
The present invention has been made in view of the above-mentioned problems, and a problem to be solved by the present invention is a method of manufacturing an electroluminescent device having a structure including a light emitting film and a fluorescence conversion film, without passing through a lithography process. The present invention provides a method for producing a fluorescence conversion film and a high-performance electroluminescent device produced by this method.

  The electroluminescence element of the present invention has a plurality of first electrodes corresponding to a pixel region on a substrate, a partition member that partitions the first electrodes and has an opening in the pixel region, and the first electrode. It has a fluorescence conversion film formed, a light emitting layer formed so as to cover the fluorescence conversion film, and a second electrode formed on the light emitting layer. In the electroluminescence element of the present invention, it is preferable that the fluorescence conversion film has conductivity. In the electroluminescence element of the present invention, it is preferable that the partition member has a light shielding property.

  In the first method of manufacturing an electroluminescent element of the present invention, a desired voltage is applied between an anode and a cathode located between the light emitting layers to cause the light emitting layers to emit light, and this light is formed for each pixel region. A method for manufacturing an electroluminescence element that obtains visible light by performing wavelength conversion using a converted fluorescent conversion film, the first step of forming a partition member having an opening corresponding to a pixel region on a substrate, and the opening A second step of discharging the fluorescent conversion film precursor into the portion using a droplet discharge head, and a third step of solidifying the fluorescent conversion film precursor discharged onto the substrate to form a fluorescent conversion film. Prepare.

  In the first method, in particular, the second step is preferably a step of discharging the fluorescent conversion film precursor while adjusting the doping ratio of the color conversion component of the fluorescent conversion film precursor.

  The fluorescence conversion film precursor is a precursor of any one of the red fluorescence conversion film, the green fluorescence conversion film, and the blue fluorescence conversion film. In this case, it is preferable to employ any one of a cyanine dye, a pyridine dye, a xanthene dye, or an oxazine dye as the composition of the precursor of the red fluorescence conversion film.

  The composition of the precursor of the red fluorescent conversion film may be, for example, (a) a rhodamine fluorescent pigment and (b) absorbing light in the blue region and transferring or transferring energy to the rhodamine fluorescent pigment. A fluorescent pigment that induces absorption and dispersed in a light-transmitting medium can be employed. Moreover, as a composition of the precursor of the said green fluorescence conversion film, a stilbene type compound and a coumarin type compound are employable, for example. Moreover, as a composition of the precursor of a blue fluorescence conversion film, a coumarin dye is employable, for example.

  In the first method, it is preferable that after the step of forming the fluorescence conversion film (third step), the light emitting layer is formed on the upper layer side of the fluorescence conversion film by a coating method or a vapor deposition method.

  In the second method for producing an electroluminescent element of the present invention, a desired voltage is applied between an anode and a cathode located between the light emitting layers to cause the light emitting layers to emit light, and this light is formed for each pixel region. A method for manufacturing an electroluminescence element that obtains visible light by wavelength conversion using a converted fluorescent conversion film, the first step of forming an anode at a position corresponding to the pixel region on the substrate, and partitioning the anode A second step of forming a partition member having an opening at a position corresponding to the pixel region; and a phosphor conversion film precursor is discharged into the opening using a droplet discharge head, and fluorescence conversion is performed on the anode. A third step of filling the film precursor; and a fourth step of solidifying the fluorescence conversion film precursor to form a fluorescence conversion film.

In the second method, in particular, the third step is preferably a step of discharging the fluorescence conversion film precursor while adjusting the doping ratio of the color conversion component of the fluorescence conversion film precursor.
Further, the fluorescence conversion film precursor has conductivity, and is a precursor of any one of the red fluorescence conversion film, the green fluorescence conversion film, and the blue fluorescence conversion film.

  In the second method, it is preferable that after the step (fourth step) of forming the fluorescence conversion film, a light emitting layer is formed on the upper layer side of the fluorescence conversion film by a coating method or a vapor deposition method.

  In the first and second methods, the contact angle between the material constituting the nozzle surface of the droplet discharge head and the fluorescent conversion film precursor is preferably in the range of 30 deg to 170 deg. The viscosity of the light conversion film precursor is preferably in the range of 1 cp to 20 cp. Moreover, it is preferable to make the surface tension of a light conversion film precursor into the range of 20 dyne / cm-70 dyne / cm. As the droplet discharge head, a head including a pressurization chamber substrate having a pressurization chamber for storing the fluorescence conversion film precursor and a piezoelectric thin film element attached at a position where the pressurization chamber can be pressurized is used. It is preferable.

  Further, according to the present invention, a desired voltage is applied between the anode and the cathode located between the light emitting layers to cause the light emitting layers to emit light, and this light is emitted by the fluorescence conversion film formed for each pixel region. An electroluminescence element that obtains visible light by conversion, and includes a fluorescence conversion film between an anode and a cathode. For example, a laminated structure of cathode / light emitting layer / fluorescence conversion film / anode is adopted. In particular, the fluorescence conversion film has conductivity, and is a fluorescence conversion film of any one of a red fluorescence conversion film, a green fluorescence conversion film, and a blue fluorescence conversion film.

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

[Embodiment 1]
The structure of the EL element according to Embodiment 1 and the manufacturing method thereof will be described with reference to FIG.

(EL element structure)
FIG. 1C shows a structure of a blue light emission / fluorescence conversion type EL element. A red fluorescence conversion film 40A, a green fluorescence conversion film 40B, and a blue fluorescence conversion film 40C are formed on the substrate 10, and are covered with a light-transmitting protective film 90. On the protective film 90, an anode 30 made of ITO (Indium Thin Oxide) is formed at a position corresponding to the fluorescence conversion films 40A to 40C. When a DC voltage is applied between the anode 30 and the cathode 60, blue light is obtained by recombination of electrons and holes in the light emitting layer 50. The blue light is converted into red (R), green (G), and blue (B) by the fluorescence conversion films 40A to 40C to obtain light or an image of RGB three colors.
In addition, when the blue light emission of the light emitting layer 50 is sufficient, the blue fluorescence conversion film 40C is unnecessary.

(EL element manufacturing process)
The manufacturing process of the EL element according to this embodiment will be described with reference to FIG.

Fluorescence conversion film precursor discharge process (FIG. 1A)
This step is a step of discharging the fluorescent conversion film precursor onto the glass substrate 10. As the glass substrate 10, for example, a flat transparent glass substrate of about 300 mm × 300 mm × 0.7 mm is prepared. As this transparent glass substrate, it is preferable to use a substrate that can withstand heat at 350 ° C., is resistant to chemicals such as acid and alkali, and can be mass-produced.

  First, a partition member (bank) 20 is formed on the glass substrate 10 in order to easily form the fluorescence conversion film in a desired shape at a desired position on the glass substrate 10. The partition member 20 has a shape having an opening corresponding to the pixel region. Examples of the material of the partition member 20 include acrylic resin and polyimide resin. The height of the partition member 20 is about 0.5 μm to 2 μm, and is adjusted as necessary. The partition member 20 may be blended with a fluorine-based resin or a fluorine-based surfactant, or the partition member 20 may be plasma-treated with CF4. If it does in this way, wettability with ink will fall and it can prevent color mixing of the ink on the partition member 20. FIG.

  The precursor of the fluorescence conversion film is supplied to the openings between the partition members 20 by discharging. The precursor of the phosphor conversion film is discharged using the droplet discharge head 2. The droplet discharge head 2 may be a piezo jet method or a method that discharges by generating bubbles due to heat generation. In the piezo jet method, the head 2 is provided with a nozzle plate and a piezoelectric thin film element on a pressure chamber substrate having a pressure chamber. By driving the piezoelectric thin film element, the fluid filled in the pressurizing chamber (in this case, the fluorescent conversion film precursor) is instantaneously pressurized and selectively discharged to a predetermined region through the nozzle. The In the method of discharging by generation of bubbles due to heat generation, the head 2 is provided with a heating element in a pressurizing chamber that communicates with the nozzle. By heating the heating element, the fluid in the vicinity of the nozzle is boiled, and the fluid is discharged by volume expansion due to bubbles generated at this time. It is preferable to adopt the piezo jet method in that there is no alteration of the fluorescent conversion film precursor due to heating.

  Specifically, as shown in the figure, first, a red fluorescent conversion film precursor 40a is discharged to a position corresponding to a pixel region on the substrate 10 (region corresponding to a red pixel). As a precursor of a red fluorescent conversion film, (a) a rhodamine fluorescent pigment, (b) a fluorescent pigment having absorption in the blue region and inducing energy transfer or reabsorption to the rhodamine fluorescent pigment, It is preferable to use those containing.

  The fluorescent pigment preferably has an absorption in a blue region of 520 nm or less and an absorption of OD1.0 or more at 420 nm to 490 nm. Moreover, it is preferable to use the said rhodamine type fluorescent pigment containing a naphthalimide type fluorescent pigment or a coumarin type fluorescent pigment. With these compositions, the emission color of the blue light-emitting layer can be converted to red with a high efficiency of 33% or more.

  Next, the precursor 40b of the green fluorescent conversion film is discharged to a position corresponding to the pixel region on the substrate 10 (region corresponding to the green pixel). As the green fluorescent conversion film precursor 40b, a precursor containing a stilbene compound and a coumarin compound pigment is preferably used.

  Further, as necessary, the blue fluorescent conversion film precursor 40c is discharged to a position corresponding to the pixel region on the substrate 10. As the blue fluorescent conversion film precursor 40c, a precursor containing a coumarin-based dye is preferably used. However, this step is not necessary when the colored light (blue) of the light emitting layer 50 is sufficient.

According to the above method, since the precursor of the fluorescence conversion film can be discharged while adjusting the doping ratio of the color conversion component of the fluorescence conversion film, color adjustment can be facilitated.
The physical property values (contact angle, viscosity, surface tension) of these fluorescent conversion film precursors are preferably the following values.

(1) Contact angle The contact angle between the material constituting the nozzle surface of the droplet discharge head and the phosphor conversion film precursor is preferably set in the range of 30 deg to 170 deg. This contact angle can be adjusted by appropriately adjusting the amount of water, NMP, DMI, ethanol, diethylene glycol and the like, and is particularly preferably set in the range of 35 deg to 65 deg.

  When the fluorescent conversion film precursor has a contact angle in this range on the nozzle surface of the discharge head, flight bending at the time of discharge can be suppressed, and precise discharge control becomes possible. When the contact angle is less than 30 deg, the wettability of the fluorescent conversion film precursor on the nozzle surface increases, and when the fluorescent conversion film precursor is discharged, the fluorescent conversion film precursor adheres asymmetrically around the nozzle holes. There is. In this case, since the attractive force acts between the fluorescent conversion film precursor attached to the nozzle holes and the fluorescent conversion film precursor to be discharged, the fluorescent conversion film precursor is discharged by non-uniform force. If a flight curve occurs, there is a fear that the target position cannot be landed, and the flight curve frequency increases. On the other hand, when the contact angle exceeds 170 deg, the interaction between the fluorescent conversion film precursor and the nozzle hole becomes minimal, and the meniscus shape at the nozzle tip is not stable, so the discharge amount and discharge timing of the fluorescent conversion film precursor are controlled. May be difficult.

  In the present invention, the flight curve means that when the phosphor conversion film precursor is ejected from the nozzle hole, the landing position of the phosphor exchange film precursor deviates from the target position by 30 μm or more. Further, the flight curve frequency refers to a point in time until the flight curve occurs when continuous ejection is performed at a vibration frequency of the piezoelectric thin film element of the droplet discharge head, for example, 14.4 kHz.

(2) Viscosity The viscosity of the fluorescent conversion film precursor is preferably in the range of 1 cq to 20 cp. This viscosity can be adjusted by appropriately changing the amount of glycerin, ethylene glycol and the like, and is particularly preferably set in the range of 2 cp to 4 cp.

  When the viscosity of the fluorescent conversion film precursor is less than 1 cp, the meniscus of the fluorescent conversion film precursor in the nozzle hole is not stable, and it may be difficult to control the discharge of the precursor. On the other hand, if the viscosity exceeds 20 cp, the fluorescent conversion film precursor cannot be smoothly discharged from the nozzle hole, and unless the specifications of the droplet discharge head such as increasing the nozzle hole are changed, the fluorescent conversion film precursor is not changed. There is a risk that it will be difficult to discharge. Furthermore, when the viscosity is large, the solid component in the fluorescent conversion film precursor is likely to be precipitated, and the nozzle hole may be clogged frequently.

(3) Surface tension The surface tension of the fluorescent conversion film precursor is preferably set in the range of 20 dyne / cm to 70 dyne / cm. This surface tension can be adjusted by appropriately changing the amount of water, NMP, DMI, ethanol, diethylene glycol, glycerin, xylene, tetralin or the like, or a mixture of these solvents, and in particular 25 dyne / cm to 60 dyne / cm. It is preferable to set within the range.

  By setting the surface tension within this range, the flight bending can be suppressed and the flight bending frequency can be reduced as in the case of the contact angle described above. When the surface tension is 70 dyne / cm or more, the meniscus shape is not stable at the tip of the nozzle, which may make it difficult to control the discharge amount and discharge timing of the fluorescent conversion film precursor. On the other hand, if the surface tension is less than 20 dyne / cm, the wettability of the fluorescent conversion film precursor with respect to the constituent material of the nozzle surface increases, so that the flight bending occurs and the flight bending frequency is high as in the case of the contact angle. There is a fear.

  This flight bend mainly occurs when the wettability of the nozzle holes is not uniform or due to clogging due to the adhesion of the solid component of the fluorescent conversion film precursor, but the droplet discharge head is cleaned (hereinafter referred to as “ This is called “flashing”). This flushing usually gives such a function to the droplet discharge head mechanism to prevent clogging and flight bending, and discharge of the phosphor conversion film precursor is performed for a certain time (hereinafter referred to as “flushing time”). ) When no longer performed, a predetermined amount of the fluorescent conversion film precursor is forcibly discharged. This flushing time means the time from when the nozzle that has not ejected the fluorescent conversion film precursor is dried to cause the flight curve, and is an index indicating the characteristics of the fluorescent conversion film precursor. Since it can be said that the longer the flushing time is, the more suitable it is for the ink jet printing technique, and therefore the fluorescent conversion film precursor can be stably discharged for a long time.

Therefore, when the fluorescence conversion film precursor has the above physical property values, the flushing time can be extended, and the interface between the atmosphere and the fluorescence conversion film precursor can be kept fresher. In addition, since the density of the dots of the phosphor conversion film precursor to be ejected can be made uniform regardless of the time of ejection, the occurrence of color unevenness in the fluorescence conversion film can be prevented. Furthermore, since it is excellent in straight flight performance when the precursor is discharged, the droplet discharge head can be easily controlled, and the manufacturing apparatus can be simplified.
In addition, the range of the said physical-property value is a suitable range in 20 degreeC temperature conditions.
After the fluorescent conversion film precursor is selectively supplied onto the substrate 10 by discharging, the fluorescent conversion film precursor is solidified by heat treatment. Through this step, the solvent component is evaporated to obtain the fluorescence conversion films 40A, 40B, and 40C.

Protective film and anode formation process ((B) in the figure)
In this step, the protective film 90 and the anode 30 are formed on the substrate 10 on which the fluorescence conversion films 40A, 40B, and 40C are formed.

  As the protective film 90, a light-transmitting material, for example, an acrylic resin is formed by a film forming method such as a spin coating method, a bar coating method, a printing method, or an ink jet method. The film thickness is 2 μm. Next, the anode 30 is formed on the surface of the protective film 90. As the material of the anode, a light-transmitting conductive material, for example, ITO, a composite oxide of indium oxide and zinc oxide, or the like is used. In particular, ITO has a large work function and functions as a positive electrode for injecting holes into the blue light-emitting layer, and thus has preferable characteristics as an anode. In this step, ITO is formed to a thickness of 0.15 μm by sputtering and patterned into a shape corresponding to the fluorescence conversion films 40A to 40C.

Blue light emitting layer and cathode formation process ((C) in the figure)
In this step, the blue light emitting layer 50 and the cathode 60 are formed on the protective film 90 so as to cover the anode 30. As a light-emitting material in the organic EL element, a low molecular weight dye molecule and a conductive polymer that is a conjugated polymer can be employed. When a low molecular material is used, an organic thin film can be formed mainly by a vapor deposition method, and when a high molecular material is used, an organic thin film can be formed by a coating method such as a spin coating method. Although not shown in the figure, a double heterostructure may be formed by forming a hole transport layer and an electron transport layer so as to sandwich the blue light emitting layer 50.

  The example of the specific film-forming method is described below. 200 mg of 4-4′bis (N-phenyl-N- (3-methylphenyl) amino) biphenyl (TPD) was placed on a molybdenum resistance heating board, and 4-4′bis ( 200 mg of 2,2-diphenylvinyl) biphenyl (DPVBi) and tris (8-quinolinol) aluminum (Alq) are added, and the inside of the vacuum chamber is decompressed. The board containing TPD is heated to 215 to 220 ° C., and TPD is deposited on the substrate at a deposition rate of 0.1 nm / s to 0.3 nm / s to form a 60 nm-thick bill transport layer. The substrate temperature at this time is room temperature. Next, DPVBi is deposited at a board temperature of 250 ° C. and an evaporation rate of 0.1 nm / s to 0.2 nm / s to form a blue light emitting layer 50 having a thickness of 40 nm. Next, Alq is further deposited at a board temperature of 250 ° C. and a deposition rate of 0.1 nm / s to 0.3 nm / s to form an electron transport layer having a thickness of 20 nm.

  In addition, as the material of the blue light emitting layer 50, dye molecules such as anthracene, Zn (OXZ) 2, PPCP, distilbenzene (DSB), and a derivative thereof (PESB) can be used. These can be formed by organic molecular beam deposition (OMDB). According to this method, film thickness control on the molecular order is possible. Further, the material of the blue light emitting layer 50 is not limited to an organic thin film, but may be an inorganic thin film such as strontium sulfide to which cerium is added. As these inorganic thin films, those having a high withstand voltage, having a light emission center having an appropriate light emission color, and having no impurities or defects that hinder light emission are preferable.

Next, the cathode 60 is formed on the blue light emitting layer 50. As the material of the cathode, a material having a small work function is preferable, and alkali metals, alkaline earth metals and the like are particularly preferable. For example, an alloy such as Mg / Ag or Al / Li is preferable. The example of the specific film-forming method is as follows. Put 0.5g of silver wire in the dungsten basket and 1g of magnesium ribbon on the molybdenum board. The inside of the vacuum chamber is depressurized, and silver (evaporation rate 0.1 nm / s) and magnesium (evaporation rate 0.8 nm / s) are vapor-deposited simultaneously to form the cathode 60.
Through the above steps, a blue light emission / fluorescence conversion type EL element is completed.

  According to this embodiment, since the fluorescence conversion film can be formed without going through a lithography process, it is possible to reduce the manufacturing cost of an EL element having a structure including the fluorescence conversion film. Moreover, since it is not necessary to make the fluorescence conversion film have photosensitivity, there is an advantage that the range of selection of materials is widened. Further, since the fluorescence conversion film precursor is discharged using the droplet discharge head to form the fluorescence conversion film, the doping ratio of the components of the fluorescence conversion film precursor can be appropriately adjusted on the spot. Therefore, it is easy to adjust the dye component of the fluorescence conversion film. The present embodiment can also be applied to a white light emission / fluorescence conversion type EL element.

[Embodiment 2]
The structure and manufacturing method of the EL element according to Embodiment 2 will be described with reference to FIGS.

(EL element structure)
The structure of the EL element is described with reference to FIG. This EL element is of a blue light emission / fluorescence conversion type. A partition member 20 is formed in a matrix on the glass substrate 10, and partitions pixel regions (light transmission regions) where the fluorescence conversion films 40A and 40B are formed. By appropriately selecting the material of the partition member 20, the light shielding function can be shared. The fluorescence conversion film 40A is a red fluorescence conversion film, and the fluorescence conversion film 40B is a green fluorescence conversion film. In each pixel region, an anode 30 made of ITO is formed. When a voltage is applied between the cathode 60 and the cathode 60, electrons injected from the cathode 60 and holes injected from the anode 30 are converted into organic substances (light emitting layer 50). ) Meet inside and form excitons that are hole-electron pairs. Blue luminescence is obtained by luminescence recombination of excitons. The blue light is converted by the fluorescence conversion film 40A in the red pixel and by the fluorescence conversion film 40B in the green pixel, and the blue light from the light emitting layer 50 is used as it is in the blue pixel, and the light source (image by RGB) is used. ) Can be obtained. In addition, in the same figure, blue light emission is not directly used as the fluorescence conversion film, but blue light emission is directly used, but when the blue light required from the light emitted from the blue light emitting layer 50 cannot be obtained, A blue fluorescence conversion film can also be provided.

(EL element manufacturing process)
The manufacturing process of the EL element of this embodiment will be described with reference to FIGS.

Anode formation process (FIG. 2A)
An anode 30 is formed on the substrate 10. The glass substrate 10 may be the same as that in the first embodiment. As the material of the anode, a light-transmitting conductive material, for example, ITO, a composite oxide of indium oxide and zinc oxide, or the like is used. In this step, ITO is deposited to a thickness of 0.15 μm by sputtering, and patterned into a shape corresponding to the pixel region by a photolithography step.

Partition member formation process (FIG. 2B)
A partition member 20 having partitions between the anodes 30 and having openings in the pixel region is formed. Various compositions can be used for the partition member 20, but in the present embodiment, a description will be given of a case where the partition member 20 is provided with a light shielding property and functions as a black matrix. As long as the partition member 20 is a material that does not transmit light and is durable, an appropriate material can be appropriately selected and used. Specifically, a black resin such as negative resin black manufactured by Fuji Hunt, resist HRB- # 01 made by Toppan Printing Co., Ltd., and resin black manufactured by Nippon Synthetic Rubber Co., Ltd. is dissolved in an organic solvent. Can be used. These resins are formed in a predetermined thickness, for example, in the range of 0.5 μm to 2.5 μm, by spin coating, dipping, spray coating, roll coating, bar coating, or the like.

In addition to these resins, metallic black, resin black in which carbon or titanium is dispersed in a photoresist, nickel, a two-layer structure of chromium and chromium oxide, or the like can be used. In this case, the partition member 20 is formed by sputtering or vapor deposition. Next, a resist (not shown) is applied on the partition member 20, and is exposed and developed into a desired pattern. The partition member 20 is etched using this resist as a mask. Through these steps, the partition member 20 partitioned and formed in a matrix is formed. The partition member 20 includes openings 21a to 21c formed according to the position of the pixel region.
In addition, the partition member 20 can also be formed by a printing method. In this case, the organic material may be directly applied in a matrix using an intaglio, a relief, a flat plate or the like.

Fluorescence conversion film precursor discharge process (FIG. 2C)
This step is a step of discharging a liquid fluorescent conversion film precursor to the openings 21a to 21c using the droplet discharge head 2. In the figure, the red fluorescent conversion film precursor 40a is discharged into the opening 21a. In the case of the present embodiment, since the fluorescent conversion film precursor is discharged onto the anode 30, the fluorescent conversion film precursor is made of a conductive material. Specifically, the composition of the red fluorescent conversion film precursor can be, for example, a mixture of a cyanine dye, a pyridine dye, a xanthene dye, or an oxazine dye mixed with a transparent conductive material. The composition of the green fluorescent conversion film precursor can be, for example, a mixture of a transparent conductive material in a stilbene compound and a coumarin compound.

When using a blue fluorescence conversion film, the composition of the precursor may be, for example, a mixture of a coumarin dye and a transparent conductive material. Here, as the transparent conductive material, an ITO alkoxide solution, a xylene dispersion solution of ITO particles, a toluene dispersion of composite oxide particles of indium oxide and zinc oxide, or the like is used.
However, when the blue light of the blue light-emitting layer is sufficient, the step of discharging the blue fluorescent conversion film precursor is not necessary.

Fluorescence conversion film precursor solidification process (FIG. 3D)
This step is a step of solidifying the fluorescent conversion film precursor discharged into the openings 21a and 21b by heat treatment. In this step, the solvent component is evaporated to obtain the fluorescence conversion films 40A and 40B.

Blue light emitting layer forming step (FIG. 3E)
This step is a step of forming the blue light emitting layer 50 so as to cover the fluorescence conversion films 40A and 40B. As a light emitting material for organic EL, there are a pigment molecule which is a low molecule and a conductive polymer which is a conjugated polymer. An organic thin film can be formed mainly by a vapor deposition method for low molecular weight materials and by a coating method such as a spin coating method for high molecular weight materials. Although not shown in the figure, a double heterostructure may be formed by forming a hole transport layer and an electron transport layer so as to sandwich the blue light emitting layer 50. A specific film forming method is the same as that in the first embodiment.

Cathode forming step (FIG. 3F)
A cathode 60 is formed on the blue light emitting layer 50. As the material for the cathode, alkali metals, alkaline earth metals and the like are preferable. For example, an alloy such as Mg / Ag or Al / Li is preferable. A specific film forming method is the same as that in the first embodiment. After forming the cathode 60, a blue light emission / fluorescence conversion type EL element is completed.

  In the EL element manufactured in the present embodiment, a droplet discharge head is used between the anode and the cathode particularly in a certain pixel (for example, a red pixel and a green pixel) as in the structure shown in FIG. The layer formed by the conventional discharge method (that is, the fluorescence conversion film) and the layer formed by the coating method or the vapor deposition method (that is, the blue light emitting layer) are laminated, and other pixels (for example, The blue pixel) has a structure in which a layer formed by a coating method or a vapor deposition method (that is, a blue light-emitting layer) is not provided between the anode and the cathode.

  According to this embodiment, since the fluorescence conversion film itself has conductivity, it is possible to provide an EL element in which the fluorescence conversion film is positioned between the anode and the blue light emitting layer. In addition, since the fluorescence conversion film can be formed without performing a lithography process, the manufacturing cost of the EL element can be reduced. Moreover, since it is not necessary to make the fluorescence conversion film have photosensitivity, there is an advantage that the range of selection of materials is widened. Further, since the fluorescence conversion film precursor is discharged using the droplet discharge head to form the fluorescence conversion film, the doping ratio of the components of the fluorescence conversion film precursor can be appropriately adjusted on the spot. Therefore, it is easy to adjust the dye component of the fluorescence conversion film.

[Embodiment 3]
A structure of an EL element according to Embodiment 3 and a manufacturing method thereof will be described with reference to FIG.

(EL element structure)
The structure of the EL element will be described with reference to FIG. In this EL element, a partition member 70 made of resist partitions each pixel region, and the anode 30 formed on the entire surface of the substrate 10 serves as a common electrode. For example, a red fluorescence conversion film 40A, a blue light emitting layer 50, and a cathode 60 are sequentially stacked in a red pixel region.

(EL element manufacturing process)
The manufacturing process of the EL element will be described with reference to FIG. A resist 70 is spin-coated on the glass substrate 10 having an ITO film formed on the surface thereof as the anode 30 ((A) in the figure). The resist 70 is patterned in accordance with the pixel region to form openings 71a to 71c (FIG. 5B). The phosphor conversion film precursor is discharged into the openings 71a and 71b using a droplet discharge head, and this is solidified to form the fluorescence conversion films 40A and 40B. Next, the blue light emitting layer 50 and the cathode 60 are formed in the openings 71a to 71c. In this case, the fluorescent conversion film precursor needs to be conductive, and specifically, the same components (materials) as in Embodiment 2 may be used.

  According to the present embodiment, the resist 70 plays a role of electrically insulating each cathode 60. Further, since the cathode 60 can be patterned in accordance with the pixel region without passing through the lithography process, the etching process, etc., the manufacturing process can be simplified. As a result, the manufacturing cost can be reduced.

[Embodiment 4]
The structure of the EL element and the manufacturing method thereof will be described with reference to FIG.

(EL element structure)
The structure of the EL element is described with reference to FIG. This EL element is an improvement of the third embodiment. An insulating film 80 is formed below the partition member 70, and this insulating film 80 functions to cut a leakage current between the cathode 60 and the anode 30 and prevent a short circuit of the element. For this reason, the reliability of the EL element is improved.

(EL element manufacturing process)
The manufacturing process of the EL element will be described with reference to FIG. An oxide film 80 is formed on the substrate 10 on which an ITO thin film is formed as the anode 30. The type of the oxide film 80 is not particularly limited as long as it is an insulating thin film, and a silicon dioxide film, a zirconium oxide film, a tantalum oxide film, a silicon nitride film, an aluminum oxide film, or the like is preferable. The insulating film 80 is patterned in accordance with the pixel region to form openings 81a to 81c (FIG. 1A). A resist 70 is spin coated over the entire surface of the substrate 10 ((B) in the figure). The resist 70 is patterned in accordance with the insulating film 80, and the resist 70 is left only on the insulating film 80 (FIG. 3C). Fluorescence conversion film precursor is discharged into the openings 81a and 81b using a droplet discharge head, and this is solidified to form the fluorescence conversion films 40A and 40B. Next, the blue light emitting layer 50 and the cathode 60 are sequentially formed in the openings 81a to 81c ((D)). Also in this case, the fluorescent conversion film precursor needs to be conductive, and specifically, the same components as those in Embodiment 2 may be used.

  According to the present embodiment, the insulating film 80 functions to cut a leakage current between the cathode 60 and the anode 30 and prevent a short circuit of the element. For this reason, the reliability of the EL element is improved. Here, by patterning the width of the resist 70 so as to be narrower than the width of the oxide film 80, the insulation between the anode 30 and the cathode 60 is structurally enhanced, which is more effective in preventing a short circuit.

  As described above in detail, according to the present invention, since the fluorescence conversion film can be formed without performing a lithography process, the manufacturing cost of the electroluminescence element can be reduced. In addition, since the fluorescence conversion film does not need to have photosensitivity, the range of material selection is widened. Furthermore, in order to obtain a fluorescence conversion film by discharging the fluorescence conversion film precursor using a droplet discharge head and solidifying it, the doping ratio of the components of the fluorescence conversion film precursor is easily adjusted as appropriate, and the fluorescence conversion characteristics Can be adjusted optimally.

It is sectional drawing which shows the manufacturing method of the EL element concerning Embodiment 1 of this invention along the process. It is sectional drawing which shows the manufacturing method of the EL element concerning Embodiment 2 of this invention along the process. It is sectional drawing which shows the manufacturing method of the EL element concerning Embodiment 2 of this invention along the process. It is sectional drawing which shows the manufacturing method of the EL element concerning Embodiment 3 of this invention along the process. It is sectional drawing which shows the manufacturing method of the EL element concerning Embodiment 4 of this invention along the process.

Claims (8)

A plurality of first electrodes corresponding to pixel regions on the substrate;
A partition member that partitions the first electrodes and has an opening in a pixel region;
A fluorescence conversion film formed on the first electrode;
An electroluminescence element comprising: a light emitting layer formed so as to cover the fluorescence conversion film; and a second electrode formed on the light emitting layer. 2. The electroluminescent device according to claim 1, wherein the fluorescence conversion film has conductivity. The electroluminescent element according to claim 1, wherein the partition member has a light shielding property. 4. The electroluminescent device according to claim 1, wherein the first electrode is an anode and the second electrode is a cathode. 5. The electroluminescent device according to claim 4, further comprising a hole transport layer between the fluorescence conversion film and the light emitting layer. The electroluminescent device according to claim 4, further comprising an electron transport layer between the light emitting layer and the cathode. The electroluminescent device according to claim 1, wherein an emission color of the fluorescence conversion film varies depending on the pixel region. Forming a plurality of anodes corresponding to pixel regions on the substrate;
Partitioning the anodes and forming a partition member having an opening at a position corresponding to the pixel region;
Discharging a fluorescent conversion film precursor into the opening using a droplet discharge head, and filling the anode with a fluorescent conversion film precursor;
Solidifying the fluorescence conversion film precursor to form a fluorescence conversion film; and
And a step of forming a light emitting layer on the fluorescence conversion film.

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