JP2011119078A - Method for manufacturing functional film - Google Patents

Abstract

Provided is a functional film manufacturing method capable of making the film thickness of a functional film formed in a pixel region uniform even if a thin film transistor is disposed in the pixel region.
In a method of applying an ink containing a functional film material to a substrate having a thin film transistor and having a pixel region formed by a bank on the transistor, the ink is applied from above the substrate. The problem can be solved by applying the ink so that it lands in a region other than the region where the transistor is formed in the pixel region.
[Selection] Figure 6

Description

  The present invention relates to a method for producing a functional film, and more particularly to a method for producing an organic electroluminescent display (hereinafter abbreviated as “organic EL display”). More specifically, an organic light emitting layer or the like is formed by an ink jet apparatus. The present invention relates to a method for manufacturing a functional film.

  Organic EL displays can be broadly classified into the following two types depending on the method of forming the organic light emitting layer. One is a method of forming an organic light emitting layer by vapor deposition, and is used when the organic light emitting layer is made of a low molecular organic material. The other is a method of forming an organic light emitting layer by a solvent coating method, and is often used not only when the organic light emitting layer is made of a low molecular organic material but also when it is made of a polymer organic material.

  One of the typical means for forming an organic light emitting layer by a solvent coating method is to form an organic light emitting layer by ejecting ink droplets containing an organic light emitting material to a pixel region of a display substrate using an inkjet device. (For example, refer to Patent Document 1). The ink droplets ejected at this time contain an organic light emitting material and a solvent.

  The ink jet apparatus has an ink jet head having a plurality of nozzles, and ejects ink from the nozzles while controlling the positional relationship between the nozzles of the ink jet head and the substrate (see, for example, Patent Document 2). Patent Document 2 discloses that liquid droplets that have landed on a substrate spread in the same direction to form pixels having a predetermined line width.

  When applied to a display device, an element such as a TFT (Thin Film Transistor) is generally disposed below a pixel region to which ink is applied.

  FIG. 11 shows a method of forming a light emitting layer by ink jetting on a pixel arranged on the switching element 214 (see Patent Document 3).

  In FIG. 11, 100 is an electroluminescence display device, 100A is a substrate, 114 is a droplet discharge head, 210R, 210G, and 210B are compartments, 211R, 211G, and 211B are liquid light emitting materials, 211FR, 211FG, and 211FB are light emitting layers, 212R, 212G, and 212B are hole transport layers, 213 is an interlayer insulating film, 214 is a switching element, 214S is a source electrode, 214G is a gate electrode, 214D is a drain electrode, 214V is a through hole, 215 is a bank, 216 is a counter electrode Reference numeral 217 denotes an inert gas, and 218 denotes a sealing substrate.

  Hereinafter, a conventional method for manufacturing an electroluminescence display device will be described.

  As shown in FIG. 11A, the light emitting material 211R is discharged from the droplet discharge head 114 to the section 210R. A layer of the light emitting material 211R is formed on all of the sections 210R and then dried to obtain the light emitting layer 211FR. Next, as shown in FIG. 11B, the light emitting material 211G is discharged from the droplet discharge head 114 to the section 210G. A layer of the light emitting material 211G is formed on all of the sections 210G and then dried to obtain the light emitting layer 211FR.

  Further, as shown in FIG. 11C, the light emitting material 211B is discharged from the droplet discharge head 114 to the section 210B. A layer of the light emitting material 211B is formed on all of the compartments 210B and then dried to obtain a light emitting layer 211FB. Then, as shown in FIG. 11D, the counter electrode 216 is provided so as to cover the light emitting layers 211FR, 211FG, 211FB and the bank 215. The counter electrode 216 functions as a cathode. Then, the electroluminescent display apparatus 100 is obtained by adhere | attaching the sealing substrate 218 and the base | substrate 100A in a mutual peripheral part.

JP 2004-362818 A JP 2003-266669 A JP 2005-218918 A

  As described above, the conventional technique only discloses application when the switching element 214 is present in the lower portion of the bank. However, a drive circuit such as the switching element 214 is disposed below the pixel of the display device, and a recess may be formed in the pixel by the drive circuit. No specific application method for making the inner film thickness uniform is disclosed. In fact, the present inventors have found that the organic EL display arranged below the pixel region is not uneven in the bank where the switching element is regulated, and the underlying substrate on which the light emitting material is applied is uneven. Faced with a scene to do.

  For example, when the thickest part such as a functional film formed by applying a light emitting material is compared with the thinnest part, the gate electrode part (not shown) is the thinnest and the thickest part wired (see FIG. There was a difference of about 900 nm. Therefore, it can be said that non-uniform film thickness is likely to occur when a light emitting material is applied.

  When the light emitting material is actually applied and the light emitting layer emits light, a luminance difference, that is, display unevenness often occurs. Although various factors can be considered for this display unevenness, it is mostly caused by a difference in film thickness of the light emitting layer. In addition, there is a form in which a flattening film is formed in order to alleviate the unevenness of the application surface of the pixel region. However, even in this case, unevenness that still affects display unevenness remains.

  In order to solve the above-described conventional problems, the present invention provides an organic EL display having a low thickness unevenness and less display unevenness even in an organic EL display having a form in which a recess is likely to be formed in the pixel area. An object of the present invention is to provide a functional film manufacturing method that can be realized.

  A functional film manufacturing method according to a first aspect of the present invention is a functional film manufacturing method in which a functional film is formed by applying an ink containing a functional film material to a substrate by an inkjet apparatus, , Having a row region defined by being sandwiched by two or more line banks parallel to each other, the row region having a pixel region arranged on a thin film transistor, and the ink jet device is arranged at a predetermined pitch. An ink-jet head having nozzles arranged in a line, and moving the ink-jet head in the scanning direction to eject the ink from the nozzles to the row region defined by the line-shaped bank and apply the ink to the substrate. Sometimes, the coating is performed so that the landing position in the pixel is landed on the uneven portion existing in the pixel so as to land on a portion other than the concave portion ”. . According to the functional film manufacturing method of the first aspect configured as described above, a display device with no unevenness of the coating film thickness distribution within the pixel and without display unevenness can be reliably realized.

  At this time, in the functional film manufacturing method according to the second aspect of the present invention, the coating is performed so as to land linearly with respect to the longitudinal direction when the coating is applied to the row region defined in the line bank. May be.

  Moreover, in the functional film manufacturing method of the 3rd viewpoint which concerns on this invention, the said organic film may be an organic light emitting layer in an organic electroluminescent display.

  As described above, according to the method for producing a functional film of the present invention, ink such as a luminescent material is landed on a portion other than the concave portion in the pixel region, and even if there is a concave portion in the pixel region, the ink bias It is possible to provide a method for manufacturing a functional film that can realize an organic EL display with reduced display unevenness and less display unevenness in the pixel region.

The top view of the board | substrate which should apply | coat the ink in the manufacturing method of the organic electroluminescent display of Embodiment 1 which concerns on this invention It is an expanded sectional view of the board | substrate in the manufacturing method of the organic electroluminescent display of Embodiment 1, (a) is sectional drawing by the AA line of the board | substrate shown in FIG. 1, (b) is the board | substrate shown in FIG. Sectional view along line B-B The figure which shows the positional relationship of the inkjet head of the inkjet apparatus used in the manufacturing method of the organic electroluminescent display of Embodiment 1, and a board | substrate. The figure which shows arrangement | positioning of the nozzle in the inkjet apparatus used in the manufacturing method of the organic electroluminescent display of Embodiment 1. FIG. The top view of the board | substrate which should apply the ink by which the driving transistor 11 is arrange | positioned in each pixel area | region 4 in the manufacturing method of the organic electroluminescent display of Embodiment 1 FIG. 5 is a diagram showing the landing position of ink 9 for each pixel region 4 of the ink jet device used in the method of manufacturing an organic electroluminescent display according to the first embodiment, and is placed on the driving transistor 11 at the landing position of XX. FIG. 5 is a diagram illustrating a case where ink is applied and a case where application is performed while avoiding the driving transistor 11 while applying linearly in the pixel region 4 at the YY landing position. Film thickness distribution after coating and drying and YY landing when ink is applied at the XX landing position in the pixel region 4 applied by the ink jet apparatus used in the manufacturing method of the organic electroluminescent display of Embodiment 1. Figure showing the film thickness distribution after coating and drying when ink is applied at a position Sectional drawing which shows schematic layer structure of the organic electroluminescent display which has the organic light emitting layer formed in the manufacturing method of the organic electroluminescent display of Embodiment 1 using the inkjet apparatus. The figure which shows the process in the manufacturing method of the organic electroluminescent display of Embodiment 1. FIG. The figure which shows the method of apply | coating avoiding on the driving transistor 11 in the manufacturing method of the organic electroluminescent display of Embodiment 2 which concerns on this invention. The figure which shows the case where it apply | coats to the pixel area | region where the switching element is arrange | positioned in the manufacturing method of the conventional organic electroluminescent display

  Hereinafter, a method for producing a functional film according to a preferred embodiment of the present invention will be described.

  In the following description, a method for manufacturing an organic EL display having an organic light emitting film (a part of a functional layer) is illustrated, and will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view of a substrate 1 on which an ink containing an organic light emitting material is to be applied, as viewed from above, in the method of manufacturing an organic EL display according to the first embodiment.

  2 is an enlarged cross-sectional view of the substrate 1 shown in FIG. 1, FIG. 2A is a cross-sectional view taken along line AA of the substrate 1 shown in FIG. 1, and FIG. FIG. 2 is a cross-sectional view taken along line BB of the substrate 1 shown in FIG.

  As shown in FIGS. 1 and 2, the substrate 1 has a bank 3 for defining a pixel region 4 on a base substrate 2. On the base substrate 2 on which the banks 3 are formed, elements necessary for an organic EL display such as a reflective anode and a hole injection layer are formed although not shown. The cross-sectional shape of the bank 3 may be a forward taper type as shown in FIG. 2 or may be a reverse taper type with a narrow skirt. As the material of the bank 3 in the first embodiment, any material can be used as long as it is an insulating material, and it is an insulating resin (for example, polyimide resin) having heat resistance and resistance to solvents. preferable. As a method for forming the bank 3, a photolithography technique or the like is used, which is formed by patterning. For example, after applying the bank material, a desired shape is formed on the base substrate 2 by baking, mask exposure, development, and the like.

  As shown in FIG. 2B, in the substrate 1, the pixel restriction layer 10 is formed on the base substrate 2, and the bank 3 is formed on the pixel restriction layer 10. The pixel regulation layer 10 is made of an inorganic material, and for example, SiON is used. The pixel restricting layer 10 is formed to extend in a line shape in a direction orthogonal to the line-shaped bank 3, and the plurality of line-shaped banks 3 and the plurality of line-shaped pixel restricting layers 10 are formed from above the substrate 1. It is formed in a lattice shape when viewed.

  Ink 9 is ejected and applied to the area regulated and partitioned by the bank 3. The surface in contact with the applied ink 9 is treated to have water repellency by fluorination treatment with oxygen-based gas plasma, fluorine-based gas plasma, or the like. Since the water repellent treatment is performed on the bank 3 as described above, even when the ink 9 is applied to the pixel region 4 as will be described later, the bank 3 reliably holds it even if it rises between the banks 3. It is securely stored in between.

  As shown in FIG. 1, the bank 3 formed on the base substrate 2 has a plurality of linear banks 3A extending linearly (extending in the left-right direction in FIG. 1). The line banks 3A are formed in parallel to each other. The row region sandwiched between the line banks 3A includes a plurality of pixel regions 4 for R (red), G (green), and B (blue). Further, the above-described pixel restriction layer 10 is formed so as to partition each pixel region 4 in each column region for R, G, and B.

  The pixel regulation layer 10 is formed so that the height from the base substrate 2 is lower than that of the bank 3. In the substrate 1 in the first embodiment, the height of the bank 3 from the base substrate 2 is, for example, about 1 μm. The layer thickness of the pixel regulation layer 10 is, for example, about 100 nm. Accordingly, the liquid ink 9 ejected into the row region surrounded by the bank 3 can freely move within the row region beyond the pixel region 4. In other words, since the amount of ink 9 ejected in each row region exceeds the layer thickness of the pixel regulating layer 10, liquid ink can travel between the pixel regions 4 in the same row region during ink ejection. State.

  In the first embodiment, the width between the plurality of adjacent line banks 3A is 60 μm. The R, G and B banks 3 formed as described above are repeatedly formed on the substrate 1.

  FIG. 3 is a diagram showing the positional relationship between the three inkjet heads 5R, 5G, and 5B for R, G, and B in the inkjet apparatus of Embodiment 1 and the substrate 1 shown in FIG.

  Each of the inkjet heads 5R, 5G, and 5B is provided with a plurality of nozzles 6 (see FIG. 4) for applying the respective R, G, and B inks. The row region is arranged so as to be a landing position (so-called landing point) of the ink 9. Since the three inkjet heads 5R, 5G, and 5B for R, G, and B have the same configuration, they will be described as the inkjet head 5 in the following description. In FIG. 3, the arrow indicated by the symbol X is the scanning direction of the inkjet head 5.

  In the first embodiment, the inkjet head 5 is described as the three inkjet heads 5R, 5G, and 5B for R, G, and B, but the nozzles for R, G, and B are provided in one inkjet head. The configuration can also be supported.

  FIG. 4 is a diagram showing a substrate facing surface having a plurality of nozzles 6 in the inkjet head 5 (5R, 5G, 5B).

  As shown in FIG. 4, in the inkjet head 5, a plurality of nozzles 6 are formed on the surface facing the substrate 1. In the inkjet head 5, a row in which a plurality of nozzles 6 are arranged in a line shape is obliquely arranged with respect to the scanning direction to the substrate 1 (the arrow X direction in FIG. 4). A plurality of rows are arranged in parallel to each other. In the inkjet head 5, the row in which the plurality of nozzles 6 are arranged in a line is arranged obliquely with respect to the scanning direction when the ink 9 is applied in the row region surrounded by the bank 3. This is because the pitch between the nozzles 6 is made short, for example, about 20 μm so that the inks 9 ejected from the nozzles 6 are connected to each other at the landing position. As described above, by arranging the plurality of nozzles 6 at an angle with respect to the scanning direction, it is possible to set the nozzle pitch interval to a desired distance.

  FIG. 5 is a drawing similar to FIG. 1 and shows that driving transistors 11 are arranged in respective pixel regions 4 for R (red), G (green), and B (blue). . In the figure, the driving transistor 11 includes a source electrode 12, a gate electrode 13, and a drain electrode 14. In the pixel region 4, when comparing the highest thickness portion with the lowest thickness portion, the gate electrode 13 is the lowest and is about 900 nm lower than the highest wiring portion (not shown).

  FIG. 6 is a diagram showing the landing position of the ink 9 with respect to each pixel region 4. XX is a case where ink is landed on the driving transistor 11 while applying the inside of the pixel region 4 in a straight line. Y-Y is applied while avoiding the driving transistor 11 while applying the inside of the pixel region 4 in a straight line. Indicates when to do.

  FIG. 7 shows the film thickness after coating and drying when ink is applied at the XX landing position in the pixel region 4 and the film thickness after coating and drying when ink is applied at the YY landing position. Show. In FIG. 7, A1 indicates the distance (film thickness) from the base of the dry film other than the driving transistor 11 region when ink is applied at the YY landing position, and B1 indicates the ink at the X-X landing position. The distance (film thickness) from the base of the dry film other than the region of the driving transistor 11 when applied is shown, and A2 is the base of the dry film in the region of the driving transistor 11 when ink is applied at the YY landing position. B2 indicates the distance (film thickness) from the base of the dry film in the driving transistor 11 region when ink is applied at the XX landing position.

  Hereinafter, a specific coating method according to the method for manufacturing the organic EL display in the first embodiment will be described.

  It is formed by applying ink 9 from each nozzle 6 of the inkjet head 5 to the glass substrate 1.

  As a method of applying the ink jet head 5 to the glass substrate 1, ink is ejected from the nozzle 6 while the ink jet head 5 is scanned with respect to the glass substrate 1. The scanning direction at this time is the same direction as the direction orthogonal to the line bank 3A in the substrate 1, as shown in FIG. The inkjet head 5 (5R, 5G, 5B) performs a coating operation on the glass substrate 1, assuming that predetermined ink 9 is ejected from the nozzle 6 to each row region for R, G, B. As described above, the ink 9 is ejected from the nozzle 6 to the substrate 1 having a plurality of row regions defined by the bank 3, and the ejection frequency at which the ink 9 is ejected from the nozzle 6 is the same as in the first embodiment. It is set to 10 kHz.

  In the first embodiment, the appropriate amount of ink applied from the ejection nozzle is the same, and the droplet amount can be converted as the number of droplets. In the first embodiment, the appropriate amount of ink discharged from each nozzle 6 is 5 pl (picoliter).

  FIG. 7 shows the film thickness after coating and drying when the coating landing position is XX in FIG. 6 and YY. The landing position XX is when applied on a straight line including on the transistor 11, and the landing position YY is when applied on a straight line in a region other than the transistor 11.

  Reference numeral 16 in FIG. 7 indicates the coating film thickness distribution at the YY landing position, and reference numeral 17 indicates the coating film thickness distribution at the XX landing position. Reference numeral 18 indicates the film thickness of the base on which the ink is applied. Reference numeral 19 denotes a transistor region, which is concave. In addition, about A1, A2, B1, and B2, it is as above-mentioned, and each shows the film thickness after drying. In the case of XX, the difference between the maximum film thickness and the minimum film thickness of YY is as small as 20 nm, while the difference between the maximum film thickness and the minimum film thickness is 35 nm.

  As described above, in the ink jet apparatus according to the first embodiment of the present invention, the ink 9 is landed linearly on a region other than on the driving transistor 11, thereby suppressing the ink bias and the film in the pixel region. It is possible to make the thickness uniform. As a result, the portion where electric field concentration occurs in the organic EL display can be reduced, the life of the organic EL display can be extended, and an electronic apparatus having a high-quality display can be provided.

  In the ink jet apparatus according to the first embodiment, since the dot density in the scanning direction is 4800 dpi (dots per inch), coating with a minimum coating pitch of 5.291667 μm is possible in the scanning direction. The application process for the substrate 1 by the ink jet apparatus is configured to be performed in one scanning operation. The application order of the R, G, B ink 9 is not particularly limited, but in the first embodiment, the application is performed in the order of R, G, B. In addition, it is preferable that the thickness of the organic light emitting layer of R, G, B formed after coating is about 50 to 100 nm (for example, 70 nm).

  In the ink jet apparatus of Embodiment 1, the organic light emitting material contained in the ink 9 is preferably a polymer light emitting material. Examples of the polymer light emitting material include polyphenylene vinylene (PPV) and Derivatives thereof, polyacetylene and derivatives thereof, polyphenylene and derivatives thereof, polyparaphenylene ethylene and derivatives thereof, poly 3-hexylthiophene and derivatives thereof (P3HT) Derivatives, polyfluorene (PF), and derivatives thereof are included. The ink viscosity was about 10 mPa · s.

  As described above, in the first embodiment, as shown in FIG. 7, after the coating process, the organic light emitting film is formed by vacuum drying and the film thickness is measured. Drying conditions were left for 30 seconds after coating, put in a drying furnace, evacuated to 1 Pa in 5 minutes, and then dried for 20 minutes while maintaining the temperature at 40 ° C. and the degree of vacuum at 1 Pa. The landing positions XX are when applied on a straight line including the transistor, and the landing positions Y-Y are when applied on a straight line in a region other than the transistor. In the case of XX, the difference between the maximum film thickness and the minimum film thickness is 35 nm, and the difference between the maximum film thickness and the minimum film thickness of YY is 20 nm. Thickness uniformity improved from 46.7% to 26.6%.

  This is considered to be due to the influence of the film thickness of the base. That is, since the drying starts immediately after the ink 9 has landed, the ink 9 has a convex thickness distribution on the concave surface, and the film height is higher than that of the non-landing portion. On the other hand, when applied to a flat surface while avoiding the concave surface, the ink 9 flows into the concave surface, but it does not become completely flat, but remains concave, and the landing part becomes higher than the height of the film on the concave surface. Conceivable.

  The variation indicating the uniformity of the film thickness is calculated using “(maximum film thickness value−minimum film thickness value) / average film thickness value × 100 [%]”.

  FIG. 8 shows an example of an organic EL display having an organic light emitting layer and the like formed using the ink jet apparatus according to the first embodiment, and is a cross-sectional view schematically showing a layer structure in the organic EL display.

  The relative film thickness and shape of each layer shown in FIG. 8 do not indicate the actual film thickness and shape, but are described in an easy-to-understand manner for explanation. In the organic EL display shown in FIG. 8, a reflective anode 23 and a hole injection layer 24 are formed on a planarizing film 22 on a base substrate, and the pixel regulation layer 10 and the bank described above are formed on the hole injection layer 24. 3 is formed. As described above, the interlayer layer (IL layer) 25 and the organic light emitting layer 26 are formed in the column region partitioned by the bank 3.

  The reflective anode 23 is separately formed corresponding to the pixel region 4 shown in FIG. 1, and serves as a light emitting portion of the display. Alternatively, after the pixel restricting layer 10 is formed, the hole injection layer 24 may be formed on the entire surface, and then the bank 3 may be formed. The pixel regulation layer 10 is formed by a normal photolithography technique. That is, the pixel regulation layer 10 is formed by the formation process of “resist coating process” → “mask exposure process” → “development process” → “dry etching process” → “resist removal process”.

  The ink jet device according to the first embodiment is used in the coating process for forming the organic light emitting layer 26, and the ink jet apparatus having the same configuration is used in the coating process for forming the interlayer layer (IL layer) 25.

  As shown in FIG. 8, in the organic EL display, an electron transport layer 27, a cathode 28, a sealing layer 29, and a resin layer 30 are formed so as to cover the organic light emitting layer 26 and the bank 3. And the glass substrate 31, the polarizing plate 32, etc. are provided in the upper part of the resin layer 30, and the organic EL display is comprised.

  The organic EL display configured as described above is manufactured as shown in the process flowchart of FIG. That is, “flattening film formation” → “reflection anode formation” → “hole injection layer formation” → “bank formation” → “IL layer formation” → “organic light emitting layer formation” → “electron transport layer formation” → “cathode” It is manufactured in the order of “formation” → “sealing layer formation” → “resin layer formation”. In this manufacturing process, the IL layer and the organic light emitting layer are generated by applying a predetermined material using the ink jet apparatus described in the first embodiment.

  As described above, in the method of manufacturing the organic EL display according to the first embodiment, the inkjet device is used in a process for generating an organic light emitting layer or the like, and even if the driving transistor is arranged in the pixel and there is a recess, the pixel By causing the ink to land on a portion other than the concave portion, it is possible to suppress the unevenness of the ink and to form a predetermined functional film having a uniform film thickness within the pixel.

  Moreover, according to the manufacturing method of the organic EL display of Embodiment 1, since the uniformity of film thicknesses, such as an organic light emitting layer which is a functional film, can be ensured, a high-quality organic EL display without luminance unevenness is obtained. Can be provided.

(Embodiment 2)
Hereinafter, a method for manufacturing an organic EL display according to Embodiment 2 of the present invention will be described with reference to the accompanying drawings.

  The manufacturing method of the organic EL display of the second embodiment is different from the manufacturing method of the organic EL display of the first embodiment described above in that the ink 9 is linearly applied when applied to a region other than on the driving transistor 11. Instead of landing, it is to be applied to a region other than the driving transistor 11. Therefore, in the description of the second embodiment, the same reference numerals are given to the components having the same configurations as those described in the first embodiment, and the description of the second embodiment uses the description of the first embodiment. Is omitted.

  FIG. 10 is a diagram showing the landing position of the ink 9 for each pixel region 4 in the second embodiment. The case where the pixel region 4 is applied to the discontinuous line 33 instead of the straight line while avoiding the driving transistor 11 is shown.

  The configurations of the organic EL display and the ink jet device in the second embodiment are the same as those in the first embodiment. Therefore, the following second embodiment will be described with reference to FIG. 1, FIG. 3, FIG. 4 and FIG. 5 used in the description of the first embodiment. The positional relationship between the substrate 1 and the nozzle 6 of the inkjet head 5 (5R, 5G, 5B) in the inkjet apparatus and the scanning direction are the same as those in the first embodiment.

  In the method of manufacturing the organic EL display according to the second embodiment, as shown in FIG. 10, by applying the ink 9 to a region other than the driving transistor 11, the film thickness after coating and drying is similar to that in the first embodiment. The difference between the maximum film thickness and the minimum film thickness is 35 nm to 18 nm as compared with the case where the film is applied on a straight line including on the driving transistor 11, and the film thickness uniformity is 46.7% to 24 with respect to the average film thickness 75 nm. % Improved.

  The variation indicating the uniformity of the film thickness is calculated using “(maximum film thickness value−minimum film thickness value) / average film thickness value × 100 [%]”.

  As described above, in the method of manufacturing the organic EL display according to the second embodiment, the ink jet device is used in a production process of an organic light emitting layer or the like, and even if the driving transistor 11 is disposed in the pixel and there is a recess, By landing the ink on a portion other than the concave portion in the pixel, it is possible to suppress the unevenness of the ink and to form a predetermined functional film having a uniform film thickness in the pixel.

  In addition, according to the method of manufacturing the organic EL display of the second embodiment, since the uniformity of the film thickness of the organic light emitting layer or the like that is a functional film can be ensured, a high-quality organic EL display without luminance unevenness is obtained. Can be provided.

  In the above, preferred Embodiment 1 and Embodiment 2 according to the present invention have been described. However, the present invention is limited to the contents of the configuration and manufacturing process of Embodiment 1 and Embodiment 2 described above. Instead, various modifications based on the same technical idea are possible.

  For example, in the first embodiment and the second embodiment, the form of the line-shaped bank 3 is shown. However, even when the pixel region 4 is a pixel in an independent region, it is applied while avoiding the driving transistor 11. Accordingly, it is possible to make the coating film thickness uniform, and the same effects as the contents of the above-described embodiment can be obtained.

  In the first and second embodiments, the normal ejection frequency of the ink ejected from the nozzles has been described as 10 kHz. However, the frequency is not particularly limited to this, and the specification of the organic EL display to be manufactured, etc. It is set accordingly. In the first and second embodiments, the dot density in the scanning direction is 4800 dpi, but is not particularly limited, and is appropriately set according to the specifications of the manufactured organic EL display.

  In the first and second embodiments, the coating process on the substrate 1 can be performed in a single scanning operation. However, the dimensions of the inkjet heads 5R, 5G, and 5B in the longitudinal direction are the same. Even if the substrate 1 is applied in a plurality of times, the same effect is obtained.

  In the first embodiment and the second embodiment, in the inkjet head, a row in which a plurality of nozzles are arranged in a line is arranged obliquely with respect to the scanning direction, and between the nozzles in the direction orthogonal to the scanning direction. The pitch was designed to be about 20 μm (for example, 21.16666 μm). This is because the ink ejected from the nozzles is connected to each other at the landing position. Therefore, the pitch between the nozzles in the direction orthogonal to the scanning direction is preferably in the range of 10 μm to 50 μm, but is not particularly limited.

  In the first and second embodiments, the amount of ink ejected from the nozzle per droplet is 5 pl, but it is preferably in the range of 1 pl to 15 pl, and is not particularly limited. . In the first and second embodiments, the ink having a viscosity of 10 mPa · s is used, but in the present invention, the viscosity of the ink is not limited to this value, and is about 5 to 20 mPa · s. It is preferably within the range of s and is not particularly limited.

  In the first and second embodiments, the driving transistor 11 is used. However, for example, when another transistor such as a switching transistor is arranged, the coating film thickness can be made uniform by the same method. This is possible and has the same effect as the contents of the above-described embodiment.

  Further, in the first and second embodiments, the case where the region other than the driving transistor 11 region is applied linearly continuously or discontinuously is shown. However, even if the region is not linear, avoid the driving transistor 11. Even if dispersed and applied, the same effect can be obtained, and a desired high-quality organic EL display can be produced.

  According to the present invention, a uniform coating film can be formed on a substrate in an ink jet apparatus. Therefore, in order to eliminate luminance unevenness, a high voltage is not applied. Since it can be provided, it is highly versatile and useful particularly in the field of organic EL displays.

3 Bank 4 Pixel region 10 Pixel restriction layer 11 Driving transistor 12 Source electrode 13 Gate electrode 14 Drain electrode

Claims (4)

In a method of applying an ink containing a functional film material to a substrate having a thin film transistor and having a pixel region formed by a bank on the transistor,
When applying ink from above the substrate, applying so that the ink lands in a region other than the region where the transistor is formed in the pixel region;
A method for producing a functional film. The ink is applied by an inkjet head having nozzles arranged in a row at a predetermined pitch,
The method for producing a functional film according to claim 1, wherein the ink is applied while moving the inkjet head in a scanning direction. 3. The bank according to claim 1, wherein the bank is configured to extend in one specific direction, and is applied so as to land in parallel with a longitudinal direction of the bank when the ink is applied to the pixel region. A method for producing a functional film. The said functional film material is a manufacturing method of the functional film as described in any one of Claims 1 thru | or 3 which is a material of the organic light emitting layer in an organic electroluminescent display.

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