JP2006261026A - Manufacturing method of electro-optical device and electro-optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an electro-optical device uniformly forming thickness of each functional layer and an electro-optical device. <P>SOLUTION: A hole transporting layer functional liquid S1 which dissolves or disperses a hole transporting layer material by a first solvent is made into a micro droplet S1a and applied on a pixel electrode 10 in a light emitting element formation region 9, then, the first solvent content is partly removed from the micro droplet S1a, and by condensing into a prescribed concentration, it is made into a concentration liquid S1b. Next, a second solvent S2 is applied by a prescribed amount on the concentration liquid S1b as a micro droplet S2a, and solvent is substituted, and it is made into a diluted solution S2b presenting liquid state again with a reduced viscosity. After that, by heating and removing the second solvent S2 in the diluted solution S2b, a hole transporting layer 11 is formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an electro-optical device and an electro-optical device.

  With respect to electronic devices equipped with a display device such as a flat panel display (FPD), a personal computer, and a mobile terminal device such as a mobile phone, market needs such as miniaturization, weight reduction, and high definition have been increasing in recent years. Along with this, display devices provided in these electronic devices are required to have similar functions. Among these, an organic electroluminescence display device (hereinafter referred to as an organic EL display) provided with an organic electroluminescence element (hereinafter referred to as an organic EL element) corresponding to each pixel as one of the electro-optical devices. The display performance is excellent because it is self-luminous with high brightness, can be driven by a low voltage direct current, and has a high response speed. An organic EL display is expected as a display device following a liquid crystal display device because the display device can be thinned, lightened, and consumes low power.

  The organic EL element, which is the light emitting layer of an organic EL display, is generally formed by a vacuum deposition method when a low molecular material is used as the organic EL material, and spin coated when a polymer material is used as the organic EL material. It is often formed by a method or a droplet discharge method (inkjet method). For example, when an organic EL element is formed by a droplet discharge method using a polymer organic EL substance, a solution of a composition in which the organic EL substance is dissolved in an organic solvent (hereinafter referred to as an organic EL functional liquid). Then, the organic EL functional liquid layer is formed by discharging to a predetermined position on the electrode of the organic EL substrate, and the organic solvent is removed from the organic EL functional liquid layer, whereby a light emitting layer can be obtained (Patent Document 1).

In manufacturing an organic EL display, it is desired to form each functional layer including a light emitting layer in a uniform thickness. However, it is difficult to satisfy both the discharge performance by the droplet discharge device required for the organic EL functional liquid and the film formability when the organic solvent is removed after the organic EL functional liquid layer is formed. In some cases, the film is formed unevenly (Patent Document 2).
Japanese Patent Laid-Open No. 10-12377 JP 2004-71506 A

  When the thickness of each functional layer including the light emitting layer becomes non-uniform as described above, current concentration occurs in the thin portion. As a result, luminance unevenness occurs in each pixel of the organic EL display, and there is a possibility that deterioration of the thin portion of each functional layer proceeds rapidly. In addition, when the film thickness difference is severe, the thin film portion may be exposed to the underlying layer electrode, which may cause a short circuit with the counter electrode formed on the functional layer.

  An object of the present invention is to provide a method of manufacturing an electro-optical device and an electro-optical device that can uniformly form the thickness of each functional layer.

In order to solve the above-described problems, the method of manufacturing an electro-optical device according to the present invention includes a liquid composition in which a light-emitting element forming material is dispersed or dissolved in a plurality of light-emitting element forming regions formed on a substrate. In the electro-optical device manufacturing method in which the functional layer is formed in each of the light emitting element forming regions by coating, a liquid state in which the light emitting element forming material is dispersed or dissolved in the respective light emitting element forming regions with a first solvent. A first coating step of applying a composition; a first drying step of removing at least a portion of the first solvent from the applied liquid composition; and a liquid from which at least a portion of the first solvent has been removed. A second coating step of adding a second solvent different from the first solvent to the composition and replacing the solvent; a second drying step of removing the solvent component from the solvent-substituted liquid composition; Have

  According to this, for example, if a material having good dispersibility or solubility with respect to the light emitting layer forming material is used as the second solvent to be applied in the second application step, the first composition can be used in the first drying step. The liquid composition formed in the light emitting layer forming region by removing at least a part of the solvent is solvent-substituted by the second solvent added in the second coating step, and uniformly dispersed in the light emitting layer forming region. Alternatively, since the film is dissolved and reformed, a functional layer having a uniform film thickness can be formed when the film is formed by completely removing the solvent component in the second drying step. Therefore, it is possible to manufacture an electro-optical device that has no luminance unevenness and has excellent display quality and high reliability.

  In the method of manufacturing the electro-optical device, the first solvent is low in volatility, and the second solvent is high in volatility and excellent in dispersibility or solubility in the light emitting element forming material. It may be.

  According to this, since the volatility of the first solvent is low, it is difficult for the liquid composition to change in viscosity in the first coating step, and thus the electro-optical device can be manufactured while maintaining stable coating properties. Is possible. In addition, since the second solvent applied in the second application step is excellent in dispersion or dissolution of the light emitting element material, the liquid composition that has undergone the first drying step is uniformly distributed in the light emitting layer forming region. Therefore, when the film is formed by completely removing the solvent component in the subsequent second drying step, a functional layer having a uniform film thickness can be formed. Furthermore, since the second solvent has high volatility, when the solvent component is removed in the second drying step, the second solvent is uniformly and rapidly from the entire surface layer of the functional layer substituted by the solvent. Since the solvent component is volatilized and removed, the formed functional layer is formed with a more uniform film thickness.

  In addition, as described above, since the functional layer having a uniform film thickness can be formed by the action of the second solvent addition, the film forming property does not have to be considered in selecting the first solvent. Selection for improving the applicability in the first application step is possible, and a liquid composition having excellent applicability can be prepared. Therefore, the applicability in the first application process is improved, and a stable application quality of the liquid composition can be obtained. Therefore, it is possible to manufacture an excellent electro-optical device having a stable display quality and the like.

In the method for manufacturing the electro-optical device, the liquid composition may be dried in the first drying step until the liquid composition is concentrated to a predetermined concentration.
According to this, since the liquid composition applied to the light emitting layer forming region in the first application step can be concentrated by controlling to a predetermined concentration rate, solvent replacement with the second solvent can be realized with high reproducibility. It is possible to stably manufacture an electro-optical device having excellent display quality and the like.

In this method of manufacturing an electro-optical device, the liquid composition may be dried until gelation in the first drying step.
According to this, the residual amount of the first solvent in the liquid composition than the method of concentrating the liquid composition applied to the light emitting layer forming region in the first application step to a predetermined concentration in the first drying step. Since the contribution of solvent replacement by the second solvent is increased and the film formation contribution of the second solvent is easily exhibited, a light-emitting layer having a uniform thickness can be formed. Thus, an electro-optical device having excellent display quality can be manufactured.

In this method of manufacturing an electro-optical device, the liquid composition may be dried until it is powdered in the first drying step.
According to this, the solvent substitution contribution ratio by the second solvent is further increased as compared with the method in which the liquid composition applied to the light emitting layer forming region in the first application step is dried until gelation in the first drying step. Therefore, a light emitting layer with a uniform film thickness can be formed, so that an electro-optical device with excellent display quality can be manufactured.

In this electro-optical device manufacturing method, the electro-optical device may be applied by a droplet discharge method at least in the first application step.
According to this, since the droplet discharge method is a coating method capable of performing fine patterning with a liquid composition in a simple process and in a short time, for example, multicoloring of a color display type electro-optical device It is possible to achieve high functionality such as high definition and high definition relatively easily. In addition, since the required amount of the liquid composition is applied to the required place, the electro-optical device can be manufactured without wasting the liquid composition even on a large-area substrate.

In this method of manufacturing an electro-optical device, the second solvent may be applied simultaneously to a plurality of light emitting element formation regions of the substrate in the second application step.
Accordingly, the second solvent can be applied to a plurality of light emitting element forming regions or all the light emitting element forming regions at the same time, instead of being applied to each light emitting element forming region of the electro-optical device substrate. Therefore, even if the electro-optical device has a large screen or high definition, the electro-optical device can be efficiently manufactured because it can be applied in a short time or in a batch.

The electro-optical device of the present invention is manufactured by the above-described electro-optical device manufacturing method.
According to this, since a functional layer having a uniform thickness can be formed, it is possible to obtain a highly reliable electro-optical device having excellent display quality and the like.

  Hereinafter, an embodiment in which the present invention is embodied in an organic EL display will be described with reference to the drawings. In the present embodiment, an organic EL display having a so-called top emission structure, in which light emitted from an organic EL element formed on a substrate is extracted not from the substrate side but from the upper part of the organic EL element, is taken as an example.

FIG. 1 is a front view illustrating an organic EL display, and FIG. 2 is a cross-sectional view of the organic EL display taken along line aa in FIG.
As shown in FIG. 1, the organic EL display 1 includes a display unit D and a flexible circuit board FC connected to the lower side of the display unit D (in the direction of arrow Y in FIG. 1).

  The display unit D includes a substrate 2. The substrate 2 is made of a material such as a glass material or a resin material. The substrate 2 is provided with a substantially rectangular display region R at the approximate center thereof. In the display region R, m × n pixels 3 are formed in a matrix. A pair of scanning line driving circuits 5 and an inspection circuit 6 are formed on the substrate 2 in a region other than the display region R (hereinafter referred to as a non-display region Q).

In the display area R, m pixels 3 groups per row are n rows in the row direction indicated by the X arrow in the figure, and n pixels 3 groups per column are indicated by the column direction indicated by the Y arrow in the figure. M rows are formed. Each pixel 3 includes a red organic EL element 4R that emits red light, a green organic EL element 4G that emits green light, and a blue organic EL element 4B that emits blue light along the row direction. The organic EL element 4R for red, the organic EL element 4G for green, and the organic EL element 4B for blue are arranged in this order. That is, the organic EL elements 4R, 4G, and 4B for each color are arranged in the row direction in a red organic EL element 4R, a green organic EL element 4G, a blue organic EL element 4B, a red organic EL element 4R, and a green color. The organic EL elements for use 4G are repeatedly arranged in this order. The color organic EL elements 4R, 4G, and 4B are arranged at the same pitch as the adjacent color organic EL elements 4R, 4G, and 4B.

  As shown in FIG. 2, each color organic EL element 4 </ b> R, 4 </ b> G, 4 </ b> B is formed on a circuit forming layer 2 b formed on the substrate 2. The circuit forming layer 2b constitutes a circuit element such as a thin film transistor T for driving each pixel 3 formed in the display region R, a scanning line driving circuit 5 or an inspection circuit 6 formed in the non-display region Q. This is a layer in which some or all of the circuit elements to be formed are formed. These are formed by patterning by vapor deposition such as sputtering or photolithography. A bank B that partitions the organic EL elements 4R, 4G, and 4B in a matrix is formed in a region corresponding to the display region R on the circuit formation layer 2b.

The surface of the bank B has liquid repellency. The bank B may be made of a material originally having liquid repellency, for example, a fluorine resin. In addition, even if it does not have liquid repellency, the organic resin such as acrylic resin and polyimide resin, which is usually used, is patterned by photolithography and the surface is made liquid repellant by CF ₄ plasma treatment etc. It may be.

  In addition, pixel electrodes 10 are formed on the bottoms of the concave light emitting element formation regions 9 defined by the banks B on the circuit formation layer 2b. The pixel electrode 10 is made of aluminum (Al) in this embodiment. Each pixel electrode 10 is electrically connected to the corresponding thin film transistor T through a contact hole H. In addition, what was laminated | stacked so far is hereafter called the organic EL display substrate 20 in this embodiment.

  A function in which a hole transport layer 11, red, green, and blue light emitting layers 12R, 12G, and 12B are stacked in this order on the pixel electrode 10 formed in each light emitting element formation region 9 of the organic EL display substrate 20. Layer 13 is formed. The light emitting layer 12R is a light emitting layer made of an organic light emitting material that emits red light, the light emitting layer 12G is a light emitting layer made of an organic light emitting material that emits green light, and the light emitting layer 12B is a blue light emitting layer. A light emitting layer made of an organic light emitting material that emits light.

  A cathode 14 is formed over the entire surface of the functional layer 13 and the bank B. A part of the cathode 14 is formed so as to cover the non-display area Q. The cathode 14 is formed of a transparent electrode using light-transmitting indium-tin oxide (ITO) or the like.

  As described above, the pixel electrode 10, the hole transport layer 11, the red organic EL element 4R, and the cathode 14 are stacked to configure the red organic EL element 4R. Further, the pixel electrode 10, the hole transport layer 11, the green organic EL element 4G, and the cathode 14 are laminated to constitute a green organic EL element 4G. Similarly, the pixel electrode 10, the hole transport layer 11, the blue organic EL element 4B, and the cathode 14 are laminated to constitute the blue organic EL element 4B.

Further, a sealing layer 15 including a sealing member made of a light-transmitting material is formed on the outer peripheral edge of the circuit forming layer 2b so as to cover the cathode 14.
As shown in FIG. 1, a pair of scanning line driving circuits 5 is disposed on the non-display area Q on the substrate 2 so as to sandwich the display area R. Each scanning line driving circuit 5 outputs a scanning signal for selecting a desired group of pixels 3 in one row among the above-described n rows of pixels 3 group. Further, as shown in FIG. 1, an inspection circuit 6 is formed on the substrate 2 and in the non-display area Q on the side opposite to the Y arrow direction from the display area R. The inspection circuit 6 is driven to inspect whether or not each color organic EL element 4R, 4G, 4B is normally driven before the organic EL display 1 manufactured through the above manufacturing process is shipped. Circuit.

  On the other hand, a data line driving circuit 7 and a control circuit 8 are formed on the flexible circuit board FC. The data line driving circuit 7 is a data signal that determines the light emission luminance of each color organic EL element 4R, 4G, 4B for the group of pixels 3 in the row selected by the scanning signal output from the scanning line driving circuit 5. Is output.

The control circuit 8 generates various control signals for drive control by the scanning line driving circuits 5 and the data line driving circuit 7 and outputs the generated control signals to the driving circuits 5 and 7, respectively.
Next, a method for forming the hole transport layer 11 and the color light emitting layers 12R, 12G, and 12B constituting the functional layer 13 of the organic EL display, which are stacked on the pixel electrode 10 in each light emitting element forming region 9, will be described in detail. .

(First application process)
FIGS. 3A to 3E are explanatory views for explaining the formation process of the hole transport layer 11 by a droplet discharge method (inkjet method).

  First, as shown in FIG. 3A, a first hole transport layer material as a light emitting element forming material is formed on the pixel electrode 10 in the light emitting element forming region 9 from the nozzle N provided in the droplet discharge head 21. A liquid composition (hereinafter referred to as “hole transport layer functional liquid”) S1 dissolved or dispersed in a solvent is discharged as fine droplets S1a. And as shown in FIG.3 (b), the micro droplet S1a is apply | coated on the pixel electrode 10 of the light emitting element formation area 9. FIG. Note that as the hole transport layer material, a triphenylamine derivative (TPD), a pyrazoline derivative, an arylamine derivative, a stilbene derivative, a triphenylenediamine derivative, or the like is used. Further, 3,4-polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) is also used as the hole transport layer material. In addition, as the first solvent, a solvent having a solubility capable of dissolving or uniformly dispersing a solute containing the hole transport layer material and a good coating property is used. Specifically, the first solvent is desirably a low volatility, that is, a relatively low saturated vapor pressure. This is because if the volatility is too high, it will volatilize and the hole transport layer material will easily clog the nozzle. In addition, the hole transport layer functional liquid is thickened by volatilization, thereby deteriorating the discharge property from the nozzle N and adversely affecting the coating property.

(First drying step)
As shown in FIG. 3B, when the microdroplet S1a is applied on the pixel electrode 10 in the light emitting element formation region 9, the process proceeds to a temporary drying process as a first drying process in which heat treatment is performed next. In the temporary drying step, the organic EL display substrate 20 is heated to partially remove the first solvent component from the fine droplets S1a applied onto the pixel electrode 10. Then, as shown in FIG. 3C, the fine droplets S1a on the pixel electrode 10 are concentrated to a predetermined concentration rate to obtain a concentrated solution S1b. At this time, it is desirable to concentrate the amount of the first solvent to 50% or less, and it is particularly desirable to concentrate to about 10% to 20%. Note that the method for concentrating the applied microdroplets S1a is not limited to heat treatment, and can also be performed by flowing a gas such as vacuum degassing or nitrogen gas.

(Second application process)
Next, as shown in FIG. 3D, a predetermined amount of the second solvent S2 is applied as fine droplets S2a from the nozzle N of the droplet discharge head 21 onto the concentrated liquid S1b in the light emitting element formation region 9. . As the second solvent S2, a solvent having excellent dispersibility or solubility of the hole transport layer material which is a solute of the hole transport layer functional liquid S1 and having high volatility, that is, a solvent having a high saturated vapor pressure is used. As the second solvent S2, a known organic solvent having these characteristics can be used. For example, xylene is preferable. For example, when 3,4-polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) is used as the hole transport layer material, the second solvent S2 is methyl alcohol, ethyl alcohol, isopropyl alcohol, or the like. Polar solvents may be used. When the second solvent S2 is applied, as shown in FIG. 3 (e), the concentrated liquid S1b that has been concentrated by temporary drying and has increased viscosity is replaced by the fine droplets S2a of the second solvent S2. Then, the viscosity is lowered again to become a diluted solution S2b which exhibits a liquid state.

  In this diluted solution S2b, since the second solvent S2 is excellent in dispersibility or solubility, the hole transport layer material in the diluted solution S2b is uniformly dispersed or dissolved in the entire light emitting element formation region 9. .

(Second drying step)
Subsequently, the organic EL display substrate 20 on which the diluent S2b is formed is heated to remove the solvent component that has been solvent-substituted with the second solvent S2 in the diluent S2b. The hole transport layer 11 is formed. At this time, since the diluent S2b has the hole transport layer material uniformly dispersed or dissolved in the entire light emitting element formation region 9 by the second solvent S2, the function of uniform film thickness can be obtained by heating and drying. A hole transport layer 11 as a layer is formed. Moreover, since the second solvent S2 has high volatility, the evaporation of the second solvent S2 is promoted substantially uniformly from the entire surface layer of the diluent S2b, so that the hole transport layer 11 after film formation is more uniform. The film thickness is formed.

  When the hole transport layer 11 is formed, next, the respective color light emitting layers 12R, 12G, and 12B as functional layers are formed on the hole transport layer 11. For the formation method, the same method as that for the hole transport layer 11 can be used. Hereinafter, an example of a method for forming the respective color light emitting layers 12R, 12G, and 12B will be described with reference to FIGS. In addition, description is abbreviate | omitted about the component which is the same as that of the said formation method of the positive hole transport layer 11, or equivalent.

  4A to 4E are explanatory views schematically showing a method for forming the red light emitting layer 12R as a representative example among the color light emitting layers 12R, 12G, and 12B constituting one pixel. 4A to 4E show a part of the structure of the organic EL display substrate 20 in the same manner as in FIGS. 3A to 3B.

(First application process)
First, as shown in FIG. 4A, a liquid composition containing a red light emitting layer material from a nozzle N provided in a droplet discharge head 21 on a hole transport layer 11 formed in a light emitting element forming region 9. F1 (hereinafter referred to as “red light emitting layer functional liquid”) is discharged as fine droplets F1a. And as shown in FIG.4 (b), the micro droplet F1a is apply | coated on the positive hole transport layer 11. FIG.

In this embodiment, the red light emitting layer functional liquid F1 is obtained by dispersing or dissolving polyfluorene, which is a red light emitting material, with cyclohexylbenzene, which is a first solvent. The cyclohexylbenzene as the first solvent dissolves or uniformly disperses the solute containing the red light emitting material (polyfluorene) in the same manner as the first solvent of the functional liquid S1 in the case of forming the hole transport layer 11. It is a solvent with solubility and good coatability. More specifically, hexylbenzene as the first solvent has low volatility, that is, high boiling point and low saturated vapor pressure, and therefore the red light emitting layer functional liquid F1 hardly causes nozzle clogging due to volatilization. Therefore, the red light emitting layer functional liquid F1 does not adversely affect the applicability by increasing the viscosity due to volatilization and deteriorating the discharge performance.

(First drying step)
Next, the process proceeds to a temporary drying step of heating the organic EL display substrate 20 in a state where the fine droplets F1a are applied. In the temporary drying step, a part of the solvent component is removed from the fine droplets F1a and concentrated at a predetermined concentration rate to obtain a concentrated solution F1b as shown in FIG. 4 (c).

(Second application process)
Subsequently, as shown in FIG. 4D, a predetermined amount of the second solvent F2 is discharged onto the concentrate F1b. Then, as shown in FIG. 4E, the concentrated liquid F1b is solvent-substituted by the second solvent F2 to disperse or dissolve the red light emitting layer material as the light emitting element forming material in the concentrated liquid F1b, and the viscosity decreases. A diluted liquid F2b exhibiting a liquid state is formed. At this time, the second solvent F2 is, as in the formation of the hole transport layer 11, excellent in dispersibility or solubility in the luminescent red light emitting element material and having high volatility, that is, saturated vapor. High pressure is used. For example, as the second solvent F2, a known organic solvent such as xylene, toluene, mesitylene, tetralin, and anisole is used.

(Second drying step)
Next, the solvent is removed from the organic EL display substrate 20 on which the diluent F2b has been formed by a method such as heating, and a red light emitting layer 12R as a functional layer is formed as shown in FIG. The red light emitting layer 12R is formed in a uniform film thickness in the element formation region by the action of the addition of the second solvent F2 as in the film formation of the hole transport layer 11 described above.

  The green light emitting layer 12G and the blue light emitting layer 12B are also formed by the same manufacturing method as the red light emitting layer 12R. Incidentally, polyphenylene vinylene or the like is used as a green light emitting layer material as a light emitting element forming material for forming the green light emitting layer 12G, and polyphenylene vinylene or polyphenylene is used as a blue light emitting layer material as a light emitting element forming material for forming a blue light emitting layer 12B. Alkylphenylene and the like are used, but not limited to these.

Next, a droplet discharge apparatus used for the droplet discharge method will be described with reference to the drawings.
FIG. 5 is a perspective view showing a configuration of a droplet discharge device for applying a liquid composition (functional liquid) containing the functional layer 13 material by a droplet discharge method (inkjet method).

  As shown in FIG. 5, the droplet discharge device 30 includes a base 31 having a rectangular parallelepiped shape. In the present embodiment, the longitudinal direction of the base 31 is the Y direction, and the direction orthogonal to the Y direction is the X direction. On the upper surface 31a of the base 31, a pair of guide concave grooves 32a and 32b extending in the Y direction are provided over the entire width in the Y direction. On the upper side of the base 31, a stage 33 provided with a linear motion mechanism (not shown) corresponding to the pair of guide grooves 32a and 32b is attached. The linear movement mechanism of the stage 33 is, for example, a screw type linear movement mechanism including a screw shaft (not shown) extending along the guide grooves 32a and 32b and a ball nut screwed to the screw shaft. The screw shaft is connected to a Y-axis motor (not shown) that receives a predetermined pulse signal and rotates forward and backward in units of steps.

  When a drive signal relative to a predetermined number of steps is input to the Y-axis motor, the Y-axis motor rotates forward or reversely, and the stage 33 is determined along the Y direction by an amount corresponding to the same number of steps. Forward or double movement (scanning in the Y direction) at a speed (scanning speed V). In the present embodiment, the position where the stage 33 is disposed on the most front side of the guide grooves 32a and 32b (base 31) (solid line position in FIG. 1) is the forward movement position, and the guide grooves 32a and 32b ( A position (a two-dot chain line position in FIG. 5) arranged at the innermost side of the base 31) is defined as a double action position.

A mounting surface 34 is formed on the upper surface of the stage 33, and a suction-type substrate chuck mechanism (not shown) is provided on the mounting surface 34. When the substrate 2 is placed on the placement surface 34, the organic EL display substrate 20 is positioned and fixed at a predetermined position on the placement surface 34 by the substrate chuck mechanism.

  A pair of support bases 35a and 35b are erected on both sides in the X direction of the base 31, and a guide member 36 extending in the X direction is installed on the pair of support bases 35a and 35b. The guide member 36 is formed so that the width in the longitudinal direction is longer than the width in the X direction of the stage 33, and one end of the guide member 36 is projected to the support base 35 a side.

  On the upper side of the guide member 36, a storage tank 36a for storing various functional liquids S1 and F1 and second solvents S2 and F2 discharged by the droplet discharge device 30 is provided. On the other hand, on the lower side of the guide member 36, a pair of upper and lower guide rails 37a and 37b extending in the X direction are provided so as to protrude over the entire width in the X direction. A carriage 38 having a linear motion mechanism (not shown) corresponding to the guide rails 37a and 37b is attached to the lower side of the guide member 36.

  The carriage 38 is formed in a rectangular parallelepiped shape, and below it is provided with a droplet discharge head 21 having nozzles N for discharging various functional liquids as droplets. The carriage 38 is formed so that its longitudinal direction (X direction) width is slightly longer than the X direction width of the stage 33. The linear movement mechanism of the carriage 38 is, for example, a screw type linear movement mechanism including a screw shaft extending in the X direction along the guide rails 37a and 37b and a ball nut screwed with the screw shaft. The motor is connected to an X-axis motor (not shown) that receives a predetermined pulse signal and rotates forward and backward in steps.

  When a drive signal corresponding to a predetermined number of steps is input to the X-axis motor, the X-axis motor rotates forward or reverse, and the carriage 38 moves forward or backward along the X direction by the amount corresponding to the same number of steps. Move (scan in X direction). In the present embodiment, the position at which the carriage 38 is disposed closest to the support base 35a of the guide rails 37a and 37b (solid line position in FIG. 5) is the forward movement position, and the guide rails 37a and 37b are also closest to the support base 35b. The position (two-dot chain line position in FIG. 5) arranged at the position is set as the backward movement position.

  Then, the organic EL display substrate 20 is positioned and fixed on the mounting surface 34 of the stage 33 of the droplet discharge device 30 and conveyed in the direction of the arrow Y while FIGS. 3 (a) to 3 (f) and FIG. 4 (a). At the timing shown in (f), it is possible to apply the fine droplets S1a, F1a, S2a, F2a from the nozzle N of the droplet discharge head 21 to the light emitting element formation region 9.

Next, the effect of the said embodiment is described below.
(1) In this embodiment, when the hole transport layer 11 is formed, first, the hole transport layer functional liquid S1 dispersed or dissolved in the first solvent having low volatility of the hole transport layer material is used. Then, the fine droplet S1a of the hole transport layer functional liquid S1 was discharged to the light emitting element formation region 9 by the droplet discharge device 30. Therefore, in the hole transport layer functional liquid S1, the first solvent is less likely to volatilize, and the hole transport layer functional liquid S1 does not thicken due to volatilization. Dischargeability can be maintained satisfactorily. As a result, the fine droplets S1a of the hole transport layer functional liquid S1 can be reliably discharged to the light emitting element formation region 9.

And after removing a part of 1st solvent in the micro droplet S1a of the hole transport layer functional liquid S1 discharged to the light emitting element formation area 9, the concentrated liquid S1b is formed, Then, it melt | dissolves in the concentrated liquid S1b The highly volatile and highly volatile second solvent S2 was discharged to make the concentrated solution S1b as the diluted solution S2b. Therefore, since the hole transport layer material is uniformly dispersed or dissolved in the entire light emitting element formation region 9 due to the excellent solubility of the second solvent S2, the diluted solution S2b has a uniform thickness. The transport layer 11 can be formed. Moreover, since the second solvent S2 also has high volatility, the evaporation of the second solvent S2 is promoted substantially uniformly from the entire surface layer of the diluent S2b.
1 is formed in a more uniform film thickness.

  (2) Moreover, in the present embodiment, the solvent (first solvent) for the hole transport layer material is discharged by discharging the second solvent S2 to the hole transport layer functional liquid S1 (concentrated liquid S1b). In the selection, the film formation contribution need not be considered, and the choice of solvent can be expanded. In addition, since it is possible to select a solvent for the purpose of improving the stability and coating properties of the hole transport layer material, it is possible to improve the coating property of the functional liquid S1 containing the hole transport layer material, thereby producing It is possible to manufacture an organic EL display excellent in display quality and the like.

  (3) In this embodiment, when forming the light emitting layers 12R, 12G, and 12B, first, the light emitting layer functional liquid F1 dissolved or dispersed in the first solvent having low volatility of the light emitting layer material is used to emit light. The fine droplets F1a of the layer functional liquid F1 were discharged to the light emitting element formation region 9 by the droplet discharge device 30. Therefore, since the light emitting layer functional liquid F1 is less likely to volatilize the first solvent and the light emitting layer functional liquid F1 does not thicken due to volatilization, the discharge characteristics of the fine droplets F1a from the nozzle N are always good. Can be maintained. As a result, the fine droplets F1a of the light emitting layer functional liquid F1 can be reliably discharged to the light emitting element formation region 9. That is, the light emitting layer material can be reliably discharged to the light emitting element formation region 9.

  And after removing a part of 1st solvent in the micro droplet F1a of the light emitting layer functional liquid F1 discharged to the light emitting element formation area 9, and forming the concentrated liquid F1b, it becomes soluble in the concentrated liquid F1b. The second solvent F2 having excellent and high volatility was discharged to make the concentrated solution F1b into the diluted solution F2b. Therefore, the diluted liquid F2b has a uniform thickness because the hole transport layer material is uniformly dispersed or dissolved in the entire light emitting element formation region 9 due to the excellent solubility of the second solvent F2. 12R, 12G, and 12B can be formed. In addition, since the second solvent F2 has high volatility, the evaporation of the second solvent F2 is promoted substantially uniformly from the entire surface layer of the diluent F2b, so that the light emitting layers 12R, 12G, and 12B are more uniform. It is formed in a film thickness.

  (4) In addition, in the present embodiment, by selecting the solvent (first solvent) for the light emitting layer material by discharging the second solvent F2 to the light emitting layer functional liquid F1 (concentrated liquid F1b), The film formation contribution need not be taken into consideration and the choice of solvent can be expanded. In addition, since it is possible to select a solvent for the purpose of improving the stability and applicability of the light emitting layer material, it is possible to improve the applicability of the functional liquid F1 containing the light emitting layer material, thereby improving the productivity. An organic EL display excellent in quality and the like can be manufactured.

  (5) Furthermore, in the present embodiment, since the film thickness of the hole transport layer 11 and the light emitting layers 12R, 12G, and 12B can be made uniform, it is possible to prevent early deterioration and short circuit due to current concentration on the thin film thickness portion. An organic EL display having high reliability can be manufactured. Further, in the hole transport layer 11, carriers (holes) are efficiently supplied to each color light emitting element while minimizing energy attenuation, and the light emitting layers 12R, 12G, and 12B become homogeneous light emitters. An organic EL display excellent in display quality can be manufactured without luminance unevenness and display unevenness in each pixel and for each pixel.

The present invention is not limited to the above embodiment, and may be implemented as follows.
In the above embodiment, the method of applying the second solvents S2 and F2 to the light emitting element formation region 9 by the droplet discharge device 30 in the second application step is shown, but the present invention is not limited to this. The organic EL display substrate 20 can also be replaced with the second solvent S2, F2 from the first solvent by exposing the organic EL display substrate 20 to the vapor atmosphere of the second solvent S2, F2.

FIG. 6 shows a solvent vapor exposure apparatus 40 that can be used in the method of replacing the first solvent with the second solvent S2 and F2, respectively, by exposing it to the vapor atmosphere of the second solvent S2 and F2.
It is a perspective view shown notionally.

  In the solvent vapor exposure apparatus 40 shown in FIG. 6, the housing 41 includes a carry-in portion opening / closing device 42 a at the carry-in port and a carry-out portion opening / closing device 42 b at the carry-out port. Further, the bottom of the casing 41 is connected to a solvent vapor supply device 44 through a solvent vapor supply port 43. The solvent vapor supply device 44 generates vapor of the second solvent S2 (or F2) and supplies it into the housing 41. Further, an exhaust device 45 is provided on the upper portion of the housing 41. The exhaust device 45 exhausts the vapor of the second solvent S2 (or F2) supplied into the housing 41.

  Then, the entrance of the housing 41 is opened by the carry-in section opening / closing device 42a, the organic EL display substrate 20 is carried into the housing 41 from the carry-in entrance and placed on the mounting table 46, and then the opening / closing device 42a. The carry-in port of the housing 41 is closed, and the vapor of the second solvent S2 (or F2) is supplied from the solvent vapor supply device 44 into the housing 41. It should be noted that the mounting table 46 can be temperature-adjustable and the organic EL display substrate 20 to be mounted can be temperature-adjusted.

  Then, the space in the casing 41 is eventually filled with the vapor of the second solvent S2 (or F2). If the temperature of the organic EL display substrate 20 is lower than the vapor temperature of the second solvent S2 (or F2), the vapor of the second solvent S2 (or F2) is condensed on the surface of the organic EL display substrate 20. The vapor of the second solvent S2 (or F2) condenses over the entire surface of the organic EL display substrate 20 where the solvent vapor contacts, but since the bank B that partitions each pixel has water repellency, the condensed second solvent The second solvent S2 (or F2) exhibits a behavior of selectively collecting only in the concave region (light emitting element formation region 9) partitioned by the bank B. As a result, the second solvent S2 (or F2) can be applied to the light emitting element formation region 9.

  In addition, although the method of providing 2nd solvent S2 (or F2) with the solvent vapor exposure apparatus 40 was shown here, it is not restricted to this. If a device having a space and a mechanism capable of creating an atmosphere of solvent vapor by controlling the vapor density and having a mechanism capable of carrying in and taking out the organic EL display substrate 20, the second solvent S2 (or F2) is used. Substrate replacement by exposure to a vapor atmosphere is possible.

  In addition, a method of applying the second solvent S2 (or F2) to substantially the entire surface of the organic EL display substrate 20 by a spray method (not shown) or the like is also applicable. Even if the second solvent S2 (or F2) is applied to the entire surface of the organic EL display substrate 20 by a spray method or the like, the second solvent for each functional layer material is obtained by the water repellent action of the bank B described above. S2 (or F2) can be given.

  According to this configuration, it is not necessary to apply the second solvent S2 (or F2) to each pixel of the substrate 20, and an electro-optical device having a large screen or a high-definition pattern can be processed in a short time, which is efficient. In addition, an electro-optical device can be manufactured.

  In the above embodiment, the first drying step is performed before adding the second solvents S2 and F2 to the micro droplets S1a and F1a of the various functional liquids S1 and F1 applied to the light emitting element formation region 9, respectively. Although the method of removing at least a part of the solvent by temporary drying or the like and concentrating to a predetermined concentration rate has been shown, the present invention is not limited to this. The fine liquid droplets S1a and F1a applied to the light emitting element formation region 9 may be gelled or powdered by controlling the solvent removal rate. The gelled or powdered hole transport layer material or light emitting layer material is dissolved in the second solvent S2, F2 added by the above-described method to form the diluted solutions S2b, F2b. The hole transport layer 11 and the light emitting layers 12R, 12G, and 12B can be obtained by removing the solvent components including the solvents S2 and F2.

  According to this configuration, the contribution rate of the solvent substitution by the second solvents S2 and F2 is improved, and the contribution rate to the film formability is increased. In addition, since the solvent substitution contribution rate by the second solvent S2 and F2 is more improved when the second solvent S2 and F2 are added after powdering than when gelled, The contribution ratio of the two solvents S2 and F2 to the film formability is high.

  In the embodiment of the present invention described above, an organic EL display has been described as an example. However, an electro-optical device such as a light-emitting device or a lighting device that forms a functional layer by applying a functional layer material including a light-emitting element forming material on an electrode It can be applied to the device.

  The organic EL display manufactured in the above embodiment may be implemented as a display unit of various electronic devices such as a mobile phone, a thin television, and a laptop computer.

FIG. 3 is a front view schematically showing an example of the configuration of an organic EL display as a representative example of the electro-optical device of the invention. Similarly, sectional drawing which shows an example of the structure of an organic electroluminescent display roughly. (A)-(f) is explanatory drawing which shows schematically the formation method of the positive hole transport layer of the organic electroluminescent display which concerns on one Embodiment of this invention. (A)-(f) is explanatory drawing which shows the formation method of a red light emitting layer roughly similarly. The perspective view which shows an example of a droplet discharge device roughly. The perspective view which shows an example of a solvent vapor exposure apparatus roughly.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Organic EL display, 2 ... Board | substrate, 2b ... Circuit formation layer, 3 ... Pixel, 4R ... Red organic EL element, 4G ... Green organic EL element, 4B ... Green organic EL element, 9 ... Light emitting element formation area, 10 ... Pixel electrode, 11 ... Hole transport layer, 12R ... Red light emitting layer, 12G ... Green light emitting layer, 12B ... Blue light emitting layer, 13 ... Functional layer, 14 ... Cathode, 20 ... Organic EL display substrate, 30 ... Droplet ejection device 40 ... Solvent vapor sealing device, B ... Bank, H ... Discharge head, N ... Nozzle, S1 ... Hole transport layer functional liquid as liquid composition, S1a ... Micro droplet, S1b ... Concentrated liquid, S2 ... No. 2 solvent, S2b ... diluent, F1 ... red light emitting layer functional liquid as a liquid composition, F1a ... fine droplets, F1b ... concentrated liquid, F2 ... second solvent, F2b ... diluted liquid.

Claims (8)

Electricity for forming a functional layer in each light emitting element forming region by applying a liquid composition in which a light emitting element forming material is dispersed or dissolved in a solvent to a plurality of light emitting element forming regions formed on the substrate. In the method of manufacturing an optical device,
Applying a liquid composition in which the light emitting element forming material is dispersed or dissolved in a first solvent to each of the light emitting element forming regions;
A first drying step of removing at least a part of the first solvent from the applied liquid composition;
A second coating step of adding a second solvent different from the first solvent to the liquid composition from which at least a part of the first solvent has been removed, and replacing the solvent;
And a second drying step of removing the solvent component from the solvent-substituted liquid composition. The method of manufacturing the electro-optical device according to claim 1,
The first solvent has low volatility,
The method of manufacturing an electro-optical device, wherein the second solvent has high volatility and is excellent in dispersibility or solubility in a light emitting element forming material. The method of manufacturing the electro-optical device according to claim 1,
In the first drying step, the liquid composition is dried until it is concentrated to a predetermined concentration. The method of manufacturing the electro-optical device according to claim 1,
In the first drying step, the liquid composition is dried until it is gelled. The method of manufacturing the electro-optical device according to claim 1,
A method of manufacturing an electro-optical device, wherein the liquid composition is dried until it is powdered in the first drying step. In the manufacturing method of the electro-optical device according to any one of claims 1 to 5,
A method of manufacturing an electro-optical device, wherein the coating is performed by a droplet discharge method at least in the first coating step. In the manufacturing method of the electro-optical device according to any one of claims 1 to 6,
In the second application step, the second solvent is applied simultaneously to a plurality of light emitting element formation regions of the substrate. An electro-optical device manufactured by the method for manufacturing an electro-optical device according to claim 1.

Images