JP4697422B2 - Manufacturing method of display device - Google Patents

Description

The present invention relates to a method for manufacturing a display device , and more particularly to a method for manufacturing a display device including a display panel in which a plurality of organic electroluminescence elements are arranged as display pixels.

  In recent years, organic electroluminescence elements (hereinafter referred to as “organic EL elements”) are being used as next-generation display devices following liquid crystal display devices (LCDs) that are widely used as monitors and displays for personal computers, video equipment, portable information equipment, and the like. Research and development of a display (display device) including a light-emitting element type display panel in which self-light-emitting elements such as light-emitting diodes (LEDs) and the like are two-dimensionally arranged have been actively conducted.

  In particular, a light-emitting element type display using an active matrix driving method has a faster display response speed, no viewing angle dependency, higher luminance and higher contrast, and higher display image quality than liquid crystal display devices. The liquid crystal display device does not require a backlight unlike the liquid crystal display device, and has a very advantageous feature that it can be further reduced in thickness and weight.

Here, an organic EL element will be briefly described as an example of a self-light-emitting element applied to a light-emitting element type display.
FIG. 9 is a schematic cross-sectional view showing one configuration example of the organic EL element.
As shown in FIG. 9, the organic EL element is roughly an organic EL device comprising an anode (anode) electrode 112, an organic compound, etc. (organic material) on one surface side (upper side in the drawing) of an insulating substrate 111 such as a glass substrate. The layer 113 and the cathode (cathode) electrode 114 are sequentially stacked.

  The organic EL layer 113 includes, for example, a hole transport layer (hole injection layer) 113a made of a hole transport material (hole injection layer forming material) and an electron transport light emitting layer (light emitting layer) made of an electron transporting light emitting material. ) 113b. Note that as the hole transport material and the electron transport light-emitting material applied to the organic EL layer 113 (the hole transport layer 113a and the electron transport light-emitting layer 113b), various organic materials of low molecular weight or high molecular weight can be used. Are known.

  Here, in general, in the case of a low molecular weight organic material, although the light emission efficiency in the organic EL layer is relatively high, since the vapor deposition method is applied in the manufacturing process, it is selectively applied only on the anode electrode in the pixel formation region. When forming a thin film, the low molecular weight material adheres to the mask surface to prevent the deposition of the low molecular weight material on the region other than the anode electrode. Has the problem of being inefficient.

  On the other hand, when a polymer organic material is applied, a droplet discharge method (so-called ink jet method) or the like can be applied as a wet film forming method, so that it is selectively applied only to the anode electrode in the pixel formation region. A thin film of an organic EL layer (a hole transporting layer and an electron transporting light emitting layer) can be satisfactorily formed by applying droplets to.

Here, a manufacturing process of an organic EL element to which a polymer organic material is applied will be briefly described.
10 and 11 are process cross-sectional views illustrating an example of a manufacturing process of a display panel (organic EL element) in the prior art. Here, for convenience of explanation, a case where only an organic EL element is formed on an insulating substrate is shown. Moreover, about the structure equivalent to the element structure of the organic EL element (FIG. 9) mentioned above, the same code | symbol is attached | subjected and demonstrated.

  As an example of the manufacturing process of the organic EL element, first, as shown in FIG. 10A, a region (pixel) on each surface of the insulating substrate 111 such as a glass substrate (on the upper side in the drawing) is formed. Formation region) After the anode electrode (anode) 112 is formed for each Apx, as shown in FIG. 10B, partition walls (banks) 121 made of an insulating resin material or the like are formed in the boundary region between adjacent display pixels. Form. Here, the anode electrode 112 is exposed in the pixel formation region Apx surrounded by the partition wall 121.

Next, as shown in FIG. 10C, active oxygen radicals are generated by irradiating the surface of the insulating substrate 111 with ultraviolet UV in an oxygen gas atmosphere, and organic substances on the surface of the anode electrode 112 are decomposed and removed. As a result, the surface of the partition wall 121 is also made lyophilic by generating radicals.
Next, the insulating substrate 111 that has been subjected to the lyophilic treatment described above is irradiated with ultraviolet rays UV in a fluoride gas atmosphere, whereby fluorine is bonded to the surface of the partition wall 121 to make it liquid repellent (or water repellent). On the other hand, the surface of the anode electrode (ITO) 112 maintains lyophilicity.

  Next, as shown in FIG. 10 (d), by using an ink jet device, a liquid material (first first material) in which a hole transport material made of a polymer organic material is dispersed or dissolved in a solvent from the ink head IHH. Solution) The HMC is ejected in the form of droplets, applied onto the lyophilic anode electrode 112, and then subjected to a drying process, whereby the positive electrode is placed on the anode electrode 112 as shown in FIG. The hole transport material 113a is formed by fixing the hole transport material.

  Next, similarly, as shown in FIG. 10F, a liquid material (second solution) obtained by dispersing or dissolving an electron-transporting light-emitting material made of a polymer organic material from the ink head IHE in a solvent. The EMC is ejected in the form of droplets, applied onto the hole transport layer 113a, and then dried, thereby fixing the electron transporting luminescent material and transporting electrons as shown in FIG. 11 (g). The light emitting layer 113b is formed. In the coating process of the liquid material HMC containing the hole transport material and the liquid material EMC containing the electron transport material, the partition 121 surface has water repellency. Even when the droplets are deposited on the partition 121, they are repelled and applied only to the lyophilic region (that is, the organic EL element formation region Ael) on the anode electrode 112 of each pixel formation region Apx.

Next, as shown in FIG. 11 (h), the common electrode is opposed to the anode electrode 112 through the organic EL layer 113 (the hole transport layer 113a and the electron transport light emitting layer 113b) in each pixel formation region Apx. After forming the cathode electrode (cathode) 114 made of, a protective insulating film and a sealing resin layer 115 are formed on the insulating substrate 111 including the cathode electrode 114, as shown in FIG. By bonding the sealing substrate 116, an organic EL element (organic EL display panel) is completed.
Such a method for manufacturing an organic EL element is described in detail, for example, in Patent Document 1 and the like.

  In the organic EL element having such an element structure, as shown in FIG. 9, by applying a positive voltage from the DC voltage source 115 to the anode electrode 112 and a negative voltage to the cathode electrode 114, the hole transport layer 113a is applied. Light (excitation light) hν is emitted based on the energy generated when the injected holes and the electrons injected into the electron-transporting light-emitting layer 113 b recombine in the organic EL layer 113.

  Here, the light hν is formed by forming the anode electrode 112 and the cathode electrode 114 by using an electrode material having a light transmitting property or a light shielding property (and reflection property), respectively, so that one surface side of the insulating substrate 111 ( The light can be emitted in any direction on the upper side of the drawing or on the other side (lower side of the drawing). At this time, the emission intensity of the light hν is determined according to the amount of current flowing between the anode electrode 112 and the cathode electrode 114.

  In FIG. 9, a transparent electrode material such as tin-doped indium oxide (ITO) is used as the anode electrode 112, and an electrode material having light-shielding and reflecting properties such as a metal material is used as the cathode electrode 114. Thus, the bottom emission structure in which the light hν emitted from the organic EL layer 113 is reflected directly or by the cathode electrode 114 and emitted to the other surface side of the transparent insulating substrate 111 is shown.

JP 2003-257656 A (Pages 4 to 6, FIGS. 2 to 5 and 8)

  In the manufacturing method of the display panel (organic EL element) as described above, the periphery of the anode electrode 112 of each display pixel (pixel formation region Apx) is surrounded by the partition 121, and the charge transport layer is interposed between the partitions 121 which are partitions. After applying a liquid as a material, the film is dried to form a charge transporting layer (for example, the hole transporting layer 113a or the electron transporting light emitting layer 113b). The liquid as the charge transport layer material applied in this way tends to aggregate on the periphery of the partition wall and the anode electrode due to the surface energy, and the charge transport layer on the center of the anode electrode becomes thin, and the film thickness Caused the problem of non-uniformity. For this reason, an attempt has been made to uniformly form a charge transport layer on the anode electrode by coating a liquid repellent film on the surface of the partition wall. However, depending on the properties of the liquid used as the charge transport layer material, the film exhibiting liquid repellency is deteriorated before being dried, and it is difficult to make the charge transport layer uniform. Here, the charge transport layer is a layer that transports electrons or holes when a forward bias is applied, and may include a light emitting region in which electrons and holes are recombined.

In view of the above-described problems, an object of the present invention is to provide a method for manufacturing a display device in which a charge transport layer having a relatively uniform film thickness is formed in a pixel formation region of a display pixel.

The invention described in claim 1
In a method for manufacturing a display device including a light emitting element having a charge transport layer,
A liquid repellent film forming step of forming a liquid repellent film on the surface of a plurality of partition walls provided on a substrate and at least the surface of which is a metal conductive layer;
A base film forming step of forming a base film by applying a base non-acidic liquid containing a charge transport layer material on the pixel electrode disposed between the plurality of partition walls;
A charge transport layer forming step of forming a charge transport layer together with the base film by applying a charge transport material-containing acidic liquid containing the charge transport layer material on the base film;
It is characterized by including.

According to a second aspect of the present invention, in the method for manufacturing a display device according to the first aspect, the liquid repellent film has a property that the liquid repellency is deteriorated by an acidic solution.
A third aspect of the present invention is the method of manufacturing a display device according to the first or second aspect, wherein the liquid repellent film contains a triazine thiol compound.

According to a fourth aspect of the present invention, in the method for manufacturing a display device according to any one of the first to third aspects, the base film forming step includes a step of immersing the substrate in a base non-acidic liquid. And
According to a fifth aspect of the present invention, in the method of manufacturing a display device according to any one of the first to fourth aspects, the charge transport layer forming step includes discharging the charge transport material-containing acidic liquid in the form of droplets, and The method includes a step of forming a charge transport layer.

A sixth aspect of the present invention is the method of manufacturing a display device according to any one of the first to fifth aspects, wherein the plurality of partition walls are wirings that are directly or indirectly connected to the light emitting element. A method for manufacturing a display device.
According to a seventh aspect of the present invention, in the method for manufacturing a display device according to any one of the first to sixth aspects, the light emitting element is connected to a light emission driving circuit having a transistor. Production method.

In the method for manufacturing a display device according to the present invention, a charge transport layer having a relatively uniform film thickness can be formed in the pixel formation region of the display pixel.

Hereinafter, a display device and a manufacturing method thereof according to the present invention will be described in detail with reference to embodiments.
(Display panel)
First, a schematic configuration of a display device (display panel) according to the present invention will be described.

  FIG. 1 is a main part schematic plan view showing one embodiment of a display device (display panel) according to the present invention, and FIG. 2 is a main part showing one embodiment of a display device (display panel) according to the present invention. It is a schematic sectional drawing. In the plan view shown in FIG. 1, for convenience of illustration, only the arrangement structure of each pixel formation region, the anode line La, and the cathode line Lc viewed from the view side is shown, and the other configuration (amorphous) shown in FIG. Transistors such as silicon thin film transistors are omitted. Here, in FIG. 1, a case where one display pixel PIX is configured by combining the color pixels PXr, PXg, and PXb including three adjacent colors of red (R), green (G), and blue (B). 2 shows a cross-sectional structure centering on the formation region Rpx of the red pixel PXr.

  As shown in FIG. 1 and FIG. 2, a display device (display panel including an organic EL element) according to an embodiment of the present invention is organic on an insulating substrate (insulating substrate) 11 such as a glass substrate. One or a plurality of transistors (in FIG. 2, two transistors T1 and T2 are shown for convenience) constituting a light emission drive circuit (light emission drive means; specific examples will be described later) for driving the EL element to emit light. ), And various wiring layers LN including an anode line La, a cathode line Lc, a data line, and a scanning line directly or indirectly connected to the transistors T1 and T2, and the transistors T1 and T2 and the wiring layer LN A protective insulating film 13 made of silicon nitride or the like and a planarizing film 14 made of a photosensitive resin or the like are laminated so as to partially cover.

  Each of the transistors T1, T2 includes, for example, a gate electrode Eg formed on the insulating substrate 11, a semiconductor layer SMC formed in a region corresponding to each gate electrode Eg via the gate insulating film 12, and the semiconductor layer The SMC includes an impurity layer OHM formed on both ends of the SMC, and a source electrode Es and a drain electrode Ed respectively formed on the impurity layer OHM. In addition, contact holes HL are appropriately formed in the protective insulating film 13 and the planarization film 14 stacked on the transistors T1 and T2 and the wiring layer LN, and a conductive layer (for example, a conductive layer on the planarization film 14) A metal material (contact metal MTL) is embedded so as to be electrically connected to a pixel electrode 15) to be described later.

  Then, the formation area of each color pixel (see the formation area Rpx of the red pixel PXr shown in FIG. 2) on the planarizing film 14 has at least light reflection characteristics, for example, the pixel electrode 15 serving as an anode electrode, An organic EL element in which an organic EL layer (charge transport layer, light-emitting layer) 16 composed of a hole transport layer 16a and an electron transport light-emitting layer 16b, and a counter electrode 17 having light transmittance and serving as a cathode electrode, for example, are sequentially stacked. Is provided.

  Further, banks (partition walls) are formed so as to protrude from the planarizing film 14 (insulating substrate 11) between the formation regions of the respective color pixels adjacent to each other (strictly, the boundary region between the formation regions of the organic EL elements). 18 (the column direction portion of the cathode line Lc in FIG. 1) is provided. Furthermore, on the insulating substrate 11 including the organic EL element and the bank 18, a sealing substrate (counter substrate) made of a glass substrate or the like so as to face the insulating substrate 11 through a transparent sealing resin layer 19. ) 20 is joined.

  In particular, in the display device (display panel) according to the present embodiment, the bank 18 defines the formation regions Rpx, Gpx,... For each color pixel PXr, PXg, PXb, and the bank 18 is made of a metal material or the like. As shown in FIG. 1, the conductive material is applied in a grid pattern between the display pixels PIX (color pixels PXr, PXg, PXb) two-dimensionally arranged on the display panel (insulating substrate 11). A metal conductive layer (cathode line Lc) can be provided. For example, as shown in FIG. 2, the counter electrode 17 of the organic EL element of each display pixel PIX (each color pixel PXr, PXg, PXb) is connected to the bank 18. The counter electrode 17 and the bank 18 are electrically connected to each other so that the bank 18 supplies a predetermined common voltage (such as a ground potential) to the counter electrode 17. For this purpose, the cathode line Lc is applied.

  In the display device having such a configuration, for example, a light emission drive circuit including transistors T1 and T2, a wiring layer LN, and the like provided in the lower layer of the display panel (the layer on the insulating substrate 11 side of the organic EL element). , A light emission drive current having a predetermined current value flows between the drain and source of the transistor T2 based on a gradation signal (display data) supplied via a data line (not shown). By being supplied to the pixel electrode 15 of the organic EL element through the contact metal MTL embedded in the contact hole HL, the organic EL element emits light with a predetermined luminance gradation corresponding to display data.

  At this time, when the organic EL element is of a top emission type, that is, the pixel electrode 15 is in contact with the light reflective electrode (as shown in FIG. 2, the reflective metal layer 15 a such as aluminum and the organic EL layer 16 are oxidized. Laminated structure of metal oxide layer 15b such as a transparent electrode material (for example, tin-doped indium oxide (ITO), zinc-doped indium oxide, etc.) such as a compound or a mixture containing at least one of indium, zinc oxide, and tin oxide When the cathode electrode 17 is a transparent conductive film such as ITO or zinc-doped indium oxide, the light emitted from the organic EL layer 16 of each display pixel PIX (each color pixel PXr, PXg, PXb) is The sealing resin layer is reflected directly through the counter electrode 17 having optical transparency or reflected by the pixel electrode 15 having optical reflection characteristics. Through 9 sealing substrate 20 direction; is emitted to the (viewing side drawing upward in FIG. 2).

  Further, when the organic EL element is a bottom emission type, that is, the pixel electrode 15 is a transparent electrode material (for example, tin-doped indium oxide) such as a compound or a mixture containing at least one of indium oxide, zinc oxide, and tin oxide. (ITO) or zinc-doped indium oxide film), and the cathode electrode 17 is oxidized with an electron injection film having a relatively low work function such as Ca, Mg, Ba, Li, and the like, and the electron injection film. It may be a laminated structure with a protective conductive film such as Al for preventing sheet resistance and reducing sheet resistance. Light emitted from the organic EL layer 16 of each display pixel is emitted through the substrate 11. In the case of the bottom emission type, the planarizing film 14 is not necessarily required. Further, the protective insulating film 13 may not be formed in the region where the pixel electrode 15 is formed.

(Manufacturing method of display device)
Next, a manufacturing method of the display device (display panel) having the above-described configuration will be described.
3 to 6 are process cross-sectional views illustrating an example of a method for manufacturing a top emission type display device (display panel) according to the present embodiment. Moreover, FIG. 7 is a chemical symbol which shows the molecular structure of the film material applied to the manufacturing method of the display apparatus (display panel) concerning this embodiment. The bottom emission type can also be manufactured by following the top emission type manufacturing method.

  In the manufacturing method of the display device (display panel) according to the present embodiment, first, as shown in FIG. 3A, each display pixel PIX is provided on one surface side (upper surface side of the drawing) of the insulating substrate 11 such as a glass substrate. A plurality of transistors T1 constituting a light emission drive circuit that generates a light emission drive current having a current value corresponding to display data and supplies it to an organic EL element for each predetermined region corresponding to each color pixel PXr, PXg, PXb. , T2, wiring layer LN, and the like are formed.

  Specifically, for example, a gate electrode Eg made of a metal material and a wiring layer connected to the gate electrode Eg are formed on one surface side of the insulating substrate 11, and then an insulating film is formed over the entire area of the insulating substrate 11. A gate insulating film 12 is formed by covering. Next, a semiconductor layer SMC made of, for example, amorphous silicon or polysilicon is formed in a region corresponding to the gate electrode Eg on the gate insulating film 12, and the semiconductor layer SMC and the source electrode are respectively formed at both ends of the semiconductor layer SMC. An impurity layer OHM for realizing an ohmic connection with Es and the drain electrode Ed is formed, and the source electrode Es, the drain electrode Ed, and a conductive film that is a source of these electrodes are patterned on the impurity layer OHM in a lump. A scan line, a data line, and an anode line La that are formed and appropriately connected to the transistors T1 and T2 are formed.

  Here, on the semiconductor layer SMC, a block layer BL for preventing etching damage to the semiconductor layer SMC when the source electrode Es, the drain electrode Ed, and the wiring layer LN are formed by patterning may be provided. . The source electrode Es, the drain electrode Ed, the scan line, the data line, and the anode line La have, for example, a laminated wiring structure made of an aluminum alloy and a transition metal in order to reduce wiring resistance and migration. is doing.

  Next, as shown in FIG. 3B, a protective insulating film (passivation film) 13 is formed so as to cover the entire area of one surface of the insulating substrate 11 including the transistors T1 and T2 and the scanning lines, data lines, and anode lines La. And the planarization film 14 are sequentially formed, and then penetrate the planarization film 14 and the protective insulating film 13 to, for example, the source electrode (or the light emission drive transistor) T2 constituting the light emission drive circuit (or The contact hole HL exposing the upper surface of the drain electrode) is formed.

  Next, as shown in FIGS. 3C and 4D, after the contact metal MTL is buried in the contact hole HL, the formation regions Rpx, Gpx,... Of the color pixels PXr, PXg,. A pixel electrode 15 electrically connected to the contact metal MTL is formed. Here, the pixel electrode 15 is specifically made of ITO or zinc so as to cover the reflective metal layer 15a after forming a thin reflective metal layer 15a having light reflection characteristics such as aluminum (Al) and patterning it. A thin metal oxide layer 15b such as doped indium oxide is formed and patterned. In order to prevent a battery reaction with the reflective metal layer 15a when patterning the upper metal oxide layer 15b, the reflective metal layer 15a is coated with a film that becomes the metal oxide layer 15b after patterning the reflective metal layer 15a. It is preferable to pattern this film so that it is not exposed.

  Thus, since the pixel electrode 15 has an electrode structure in which the lower reflective metal layer 15a and the upper metal oxide layer 15b are stacked, the upper surface and the end surface of the reflective metal layer 15a are covered with the metal oxide layer 15b. Therefore, even when the etching conditions of the reflective metal layer 15a and the metal oxide layer 15b are different, the lower reflective metal layer 15a is overetched or damaged by etching when the metal oxide layer 15b is formed by patterning. Can be prevented.

  As described above, the metal oxide layer 15b constituting the upper layer of the pixel electrode 15 is made of a transparent electrode material (for example, tin-doped oxide) such as a compound or a mixture containing at least one of indium oxide, zinc oxide, and tin oxide. Indium (ITO), zinc-doped indium oxide, etc.) are deposited using an electron beam evaporation method, sputtering method, ion plating method, etc., and then patterned in accordance with the planar shape (light emitting region) of the organic EL element It is formed by doing.

  Next, regions between the pixel electrodes 15 formed corresponding to the formation regions Rpx, Gpx,... Of the color pixels PXr, PXg,... (That is, formation of the color pixels PXr, PXg,. As shown in FIG. 4E, a bank base layer 21 made of an inorganic insulating material such as a silicon nitride film is formed in the regions Rpx, Gpx,...

  Furthermore, as shown in FIG. 4 (f), on the bank underlayer 21, for example, at least the surface is made of copper, silver, aluminum, or a non-oxide such as a simple metal or an alloy containing these as a main component. A bank metal portion 18b (metal conductive layer; corresponding to the cathode line Lc shown in FIG. 1) made of a low-resistance metal material is formed. As a result, the region surrounded by the bank (partition wall) 18 composed of the bank metal portion 18b (cathode line Lc) and the bank base layer 21 is formed into the formation regions Rpx, Gpx,... (That is, the color pixels PXr, PXg,. , A light emitting region in an organic EL element). The bank metal portion 18b formed in the bank 18 may be plated with gold in order to prevent oxidation. Instead of the bank metal portion 18b, a non-conductive material (for example, polyimide) having the same shape may be used, and the surface may be plated with metal to impart conductivity.

Next, as shown in FIG. 5 (g), a liquid repellent thin film (liquid repellent property) comprising a coating 18c of a triazine thiol compound such as triazine trithiol or a fluorine-based triazine dithiol derivative on the surface of the bank metal portion 18b. Film) is selectively formed. Specifically, the insulating substrate 11 formed up to the bank 18 is cleaned by UV ozone cleaning, and then inserted into a tank filled with an aqueous solution of a triazine thiol compound and immersed in the aqueous solution. The temperature of the aqueous solution in this step is approximately 20 to 30 ° C., and the immersion time is approximately 1 to 10 minutes. At this time, the triazine thiol compound is selectively bonded to the metal. However, the metal oxide, the organic insulating film, and the inorganic insulating film are not coated to the extent that they exhibit liquid repellency. Next, the insulating substrate 11 taken out from the aqueous solution is rinsed with alcohol to wash away the excess triazine thiol compound on the insulating substrate 11, followed by secondary cleaning with water, and then by blowing nitrogen gas (N ₂ ). dry.

Here, as an example of the triazine thiol compound, the fluorine-based triazine dithiol derivative as described above is a nitrogen (-N) of triazine (six-membered ring structure containing three nitrogens) as shown in FIG. In addition to a molecular structure in which a thiol group (—SH) is bonded to an alkyl group (—CH ₂ —CH ₂ —) and a fluorinated alkyl group (—CF ₂ —CF ₂ ) on the S atom of a specific thiol group (—SH) -CF ₂ -CF ₃ ) are sequentially bonded to each other, and like the other triazine thiol compounds, as shown in FIG. 7B, they are selectively bonded to the surface of the bank metal portion 18b. Although the film 18c that makes the surface of the metal part 18b liquid-repellent is coated, it does not bond to the metal oxide, the organic insulating film, and the inorganic insulating film to the extent that they clearly show liquid repellency. Since this fluorine-based triazine dithiol derivative contains fluorine atoms exhibiting liquid repellency in addition to triazine trithiol which itself exhibits liquid repellency, the coating film 18c has stronger liquid repellency than triazine trithiol. Show. In addition, the density | concentration of the aqueous solution used in the process mentioned above has the preferable range of about 1 * 10 ^{< -4} > ^-1 * 10 ^<-2 > mol / L in general.

In the above fluorine-based triazine dithiol derivative, the S atom of the thiol group was bonded to the alkyl group (—CH ₂ —CH ₂ —), but it may be directly bonded to the fluorinated alkyl group, and significant steric hindrance. Unless it becomes, there is no special restriction | limiting in carbon number of an alkyl group and a fluoroalkyl group. Further, in the fluorine-based triazine dithiol derivative, in one S atom of the remaining two thiol groups, a fluorinated alkyl group may be substituted directly or indirectly in place of a hydrogen group, or contains a fluorine atom. Between the carbons of the group may have an olefin double bond. As other triazine thiol derivatives, for example, 6-dimethylamino-1,3,5-triazine-2,4-dithiol-sodium salt or 6-didodecylamino-1,3,5-triazine-2,4 -Dithiol-sodium salt may be used, and the film 18c may be coated by dissolving in water.

  Thereby, the coating 18c of the triazine thiol compound is formed only on the surface of the bank metal portion 18b made of a metal material among the respective components formed on the one surface side of the insulating substrate 11, while the metal oxide layer (ITO or the like) is formed. ) It is difficult to adhere to the surface of the pixel electrode 15 covered with 15b, the surface of the bank base layer 21, and the planarizing film 14 (or the protective insulating film 13) exposed between the pixel electrodes 15, and no film is formed. Therefore, on the same insulating substrate 11, only the surface of the bank metal portion 18b is subjected to a liquid repellent treatment, and the surface of the pixel electrode 15 exposed to the formation regions Rpx, Gpx,. A state where the liquid repellent treatment is not performed is realized.

  In addition, “liquid repellency” used in the present embodiment includes an organic compound-containing liquid containing a hole transport material to be a hole transport layer described later and an electron transport light-emitting material to be an electron transport light-emitting layer. When a contact angle is measured by dropping an organic compound-containing liquid or an organic solvent used in these solutions onto an insulating substrate or the like, the contact angle is defined as a state where the contact angle is 50 ° or more. . Further, “lyophilic” with respect to “liquid repellency” is defined as a state in which the contact angle is 40 ° or less in the present embodiment.

  Next, a hole transport layer is formed on the formation regions Rpx, Gpx,... Of the color pixels PXr, PXg,... Defined by the bank metal portion 18b (bank 18) whose surface is made liquid-repellent by the coating 18c of the triazine thiol compound. 16a is formed. Specifically, first, the insulating substrate 11 that has been subjected to the above-described liquid repellency treatment is a solution or dispersion (hereinafter referred to as the following) in which a relatively lipophilic polyethylenedioxythiophene (PEDOT) is dissolved or dispersed in an organic solvent. Dipping in a “non-acidic liquid for base”). As the organic solvent, ethanol (boiling point 78.3 ° C.), acetonitrile (boiling point 81.6 ° C.), and nitrocetane (boiling point 101 ° C.) are preferable. In particular, an organic solvent having a boiling point of 100 ° C. or lower can quickly dry the non-acidic base solution before the PEDOT aggregates locally, so that the PEDOT film can have a relatively uniform thickness. The drying temperature is preferably from the boiling point of the organic solvent to 150 ° C.

  As a result, as shown in FIG. 5 (h), the surface of the pixel electrode 15 (metal oxide layer 15b) exposed in the formation regions Rpx, Gpx,... Of each color pixel PXr, PXg,. A thin film (lyophilic film) made of polyethylene dioxythiophene PEDOT is selectively formed as the base film 16x. Here, since the liquid in which polyethylenedioxythiophene PEDOT is dispersed or dissolved is neutral (non-acidic) (has non-oxidizing characteristics), this non-acidic liquid for base is applied to the surface of the bank metal portion 18b. Even if a manufacturing method in contact with the provided coating 18c is applied, the liquid repellent property can be maintained well without deteriorating (removal by etching, peeling, etc.) the coating 18c of the triazine thiol compound. The metal material constituting the bank 18 (bank metal portion 18b) inside 18c is not deteriorated (removed by oxidation, etching, peeling, or the like). Accordingly, it is possible to easily form the base film 16x collectively by immersing the entire substrate 11 with the base non-acidic liquid by a dip coating method or a spin coating method.

  As described above, on the same insulating substrate 11, the surface of the bank 18 (bank metal portion 18b) is coated with the triazine thiol compound 18c without being deteriorated by the base non-acidic liquid. The surface of the pixel electrode 15 exposed to the formation regions Rpx, Gpx,... Of the color pixels PXr, PXg,... Defined by the bank 18 is made of polyethylenedioxythiophene PEDOT. The base film 16x realizes a state (having lyophilicity) that is easy to become familiar with the hole transport material described later.

  Next, as shown in FIG. 6 (i), droplets individually separated from the ink head are discharged to the formation regions Rpx, Gpx,... Of the color pixels PXr, PXg,. Applying an inkjet method or a nozzle coating method that discharges the liquid in a continuous liquid state without separation, an aqueous solution of the hole transport material is applied in the form of droplets, and then the aqueous solution is dried to form the hole transport layer 16a. Form. Specifically, as an acidic organic compound-containing liquid (charge-transporting material-containing acidic liquid) containing an organic polymer-based hole transporting material, for example, a polyethylenedioxythiophene / polystyrenesulfonic acid aqueous solution (PEDOT / PSS; conductive) Polyethylene dioxythiophene PEDOT which is a polymer and a polystyrene sulfonic acid PSS which is a dopant are dispersed in an aqueous solvent). PSS is used as a dopant that improves the solubility in water, and the polyethylene dioxythiophene / polystyrene sulfonic acid aqueous solution exhibits acidity when PSS is added. This aqueous solution is ejected in the form of droplets from an ink head (not shown), and is applied onto the pixel electrode 15 (metal oxide film 15b) on which the base film 16x is formed, that is, on the base film 16x, and then nitrogen. By performing a drying process in an atmosphere to remove the solvent, the organic polymer hole transport material is fixed on the pixel electrode 15 to form the hole transport layer 16a which is a charge transport layer.

  At this time, the charge transport material-containing acidic liquid (polyethylenedioxythiophene / polystyrenesulfonic acid aqueous solution PEDOT / PSS) dropped on the pixel electrode 15 (the surface of the base film 16x) is applied to the surface of the pixel electrode 15 (metal oxide film 15b). Since the droplets are easily wetted and familiar with the base film 16x made of polyethylenedioxythiophene PEDOT, the formation regions Rpx, Gpx,... For each color pixel PXr, PXg,. The hole transport layer 16a having a uniform film quality and film thickness can be formed with good spread over the entire region. On the other hand, the acidic liquid containing the charge transport material deposited on the surface of the bank 18 (bank metal portion 18b) subjected to the liquid repellency treatment with the coating film 18c of the triazine thiol compound is quickly adapted before the liquid repellency of the coating film 18c is deteriorated. The base film 16x is easily moved. Further, since the base film 16x becomes a part of the hole transport layer, the hole transport layer 16a having a sufficient thickness can be formed even if the amount of the acidic liquid containing the charge transport material applied on the base film 16x is reduced. . For this reason, since the amount of the charge transport material-containing acidic liquid to be applied is small, the coating film 18c is quickly dried before the liquid repellency of the coating 18c is deteriorated, so that a uniform film thickness can be obtained.

  As described above, in the present embodiment, the formation regions Rpx, Gpx,... Of the respective color pixels PXr, PXg,... Are positively formed using the polyethylenedioxythiophene / polystyrenesulfonic acid aqueous solution PEDOT / PSS. When forming the hole transport layer 16a, the base film 16x is preliminarily familiar with at least the polyethylenedioxythiophene / polystyrene sulfonic acid aqueous solution PEDOT / PSS (for example, the components constituting the charge transport material-containing acidic liquid). A thin film made of a material having the property that the droplets are uniformly distributed) is formed. Thereby, aggregation of the hole transport material can be suppressed, and the hole transport layer 16a having a uniform film quality and film thickness can be formed.

  In particular, the polyethylenedioxythiophene / polystyrenesulfonic acid aqueous solution PEDOT / PSS for forming the hole transport layer 16a uses polystyrenesulfonic acid PSS as a dopant in order to disperse insoluble polyethylenedioxythiophene PEDOT in an aqueous solvent. However, this polystyrene sulfonic acid PSS causes the aqueous solution to be acidic. Therefore, when such an acidic solution directly deposits on the bank 18 (bank metal portion 18b) in a sufficient amount as a charge transport layer material, the aqueous solution is dried. It takes time until the metal material constituting the bank metal portion 18b and the coating film 18c of the triazine thiol compound formed on the surface are deteriorated (removed by oxidation, etching, peeling, etc.) and liquid repellent on the surface of the bank 18 Conductivity is not maintained, and conductivity is reduced. The reduction. Since the liquid repellency is not maintained, the charge transport layer material aggregates between the peripheral edge of the pixel electrode 15 and the bank metal portion 18b, and the film thickness becomes non-uniform.

  Therefore, in the present embodiment, by applying a charge transport material (PEDOT) having non-oxidation characteristics to the metal material constituting the bank metal portion 18b and the coating 18c of the triazine thiol compound having liquid repellency, During the dipping process (dip coating) for forming the base film 16x, the deterioration of the surface of the bank 18 (bank metal portion 18b) is suppressed, and the formation regions Rpx, Gpx,... Of the respective color pixels PXr, PXg,. A base film 16 x can be selectively formed on the pixel electrode 15. Since the base film 16x becomes a part of the charge transport layer, the amount of the charge transport material-containing acidic solution can be reduced, and therefore the time for the coating 18c to be immersed in the charge transport material-containing acidic solution is shortened. The acidic liquid containing the charge transport material can be dried while maintaining the water repellency on the surface, and the film thickness can be made uniform.

  Here, the material liquid of the base film 16x as described above may be a non-acidic liquid and may contain a charge transport material. Specifically, a copolymer of polyethylenedioxythiophene PEDOT and polyethylene glycol PEG, A non-acidic (non-oxidizing property) organic dispersion such as a polyethylenedioxythiophene PEDOT oligomer end-capped with a methacryl group can be favorably applied.

Moreover, as a solvent for the material of the base film 16x, an organic solvent having a low boiling point can be favorably applied. According to this, after the insulating substrate 11 is immersed in the organic dispersion, it is taken out and dried. In the process, since the evaporation of the solvent proceeds relatively quickly, a polyethylenedioxythiophene / polystyrenesulfonic acid aqueous solution PEDOT / PSS having a relatively high boiling point and a slow solvent evaporation rate is dropped directly on the pixel electrode 15. Compared with the case of drying and fixing, it is possible to suppress the aggregation of the material of the base film 16x and reduce the variation in film quality and film thickness.
Furthermore, the film thickness of the base film 16x formed on the pixel electrode 15 is specifically equal to or greater than the average roughness (Ra) of the surface of the pixel electrode 15 (metal oxide film 15b), and the average roughness It is desirable to set it to 2 times (2 × Ra) or less.

  Next, as in the case of the hole transport layer 16a, as shown in FIG. 6 (i), the formation regions Rpx, Gpx,... Of the color pixels PXr, PXg,. The ink-transporting light-emitting material aqueous solution is applied in the form of droplets by applying an inkjet method, and then the aqueous solution is dried to form the electron-transporting light-emitting layer 16b. Specifically, as a charge transport material-containing acidic liquid (compound-containing liquid) containing an organic polymer-based electron transport light-emitting material, for example, a polyfluorene-based or polyparaphenylene vinylene-based light-emitting material such as tetralin, tetra A solution dissolved in an organic solvent such as methylbenzene, mesitylene, xylene or the like is discharged in the form of droplets from a nozzle bed (not shown), applied onto the hole transport layer 16a, and then heated in a nitrogen atmosphere. The organic polymer electron transporting light-emitting material is fixed on the hole transporting layer 16a by removing the solvent by performing a drying process by using a sheath heater or the like in a vacuum atmosphere, and charge transporting. The electron transporting light emitting layer 16b which is a layer is formed. Here, as the light emitting material, a material having each color of red, green, and blue corresponding to the formation regions Rpx, Gpx,... Of the respective color pixels PXr, PXg,.

  At this time, since the acidic liquid (electron transporting light-emitting material) containing the charge transport material is easily wetted with respect to the dried hole transport layer 16a, the formation regions Rpx, Gpx,... Of the color pixels PXr, PXg,. The electron transporting light emitting layer 16b having a uniform film quality and film thickness can be formed that spreads well over the entire region. On the other hand, the charge transport material-containing acidic liquid deposited on the surface of the bank 18 (bank metal portion 18b) made liquid repellent by the coating 18c of the triazine thiol compound is repelled and does not fix on the film. Thereby, the organic EL layer 16 (the hole transport layer 16a and the electron transporting light emitting layer 16b) having a uniform film quality and film thickness can be formed on the pixel electrode 15.

  Next, as shown in FIG. 6 (j), a transparent electrode layer is formed on the insulating substrate 11 including the formation regions Rpx, Gpx,... For the color pixels PXr, PXg,. A counter electrode 17 facing the pixel electrode 15 is formed through the EL layer 16 (the hole transport layer 16a and the electron transport light emitting layer 16b). Here, the counter electrode 17 includes, for example, formation regions of the color pixels PXr, PXg,... From at least the formation regions Rpx, Gpx,. Are formed as a single common electrode extending up onto the bank 18 defining Rpx, Gpx,. Specifically, the counter electrode 17 is made of a metal material having a relatively low work function, such as calcium (Ca), barium (Ba), indium (In), or the like, by a vacuum vapor deposition method, a sputtering method, or the like. It has a structure in which a thin film is formed with a film thickness (for example, about 10 nm to 20 nm) of a wavelength or less (approximately 400 nm or less), and a transparent electrode film such as, for example, ITO is laminated thereon.

  As a result, the lower metal material such as indium, which is a lower layer, adheres to the organic material constituting the organic EL layer 16 (electron transporting light emitting layer 16b) in an electrically good state, and visible light. Therefore, the light emitted from the organic EL layer 16 can be transmitted satisfactorily. Further, the transparent electrode film such as ITO of the upper layer is formed in a layered form for the purpose of reducing the resistance of the counter electrode 17 in order to increase the resistance by forming the metal film of the lower layer extremely thin to 400 nm or less. Further, the counter electrode 17 is formed so as to extend over the bank 18, so that the counter electrode 17 and the counter electrode 17 are formed through the triazine thiol compound coating 18 c formed extremely thin on the surface of the bank metal portion 18 b. The bank metal portion 18b (cathode line Lc) can be electrically connected well.

  Next, as shown in FIG. 2, a transparent sealing resin layer 19 is formed on one surface side of the insulating substrate 11 including the formation regions Rpx, Gpx,... And the banks 18 of the color pixels PXr, PXg,. After that, by joining the sealing substrate 20 so as to face the insulating substrate 11, a display panel in which a plurality of display pixels PIX (a combination of the color pixels PXr, PXg, and PXb) is two-dimensionally arranged is completed. To do. Here, as a method of bonding the sealing substrate 20 to the insulating substrate 11, a UV curable adhesive or a thermosetting adhesive is applied to the bonding surface side of the sealing substrate 20 and bonded to the insulating substrate 11. Thereafter, a method of curing and bonding the adhesive by UV irradiation or heat treatment can be applied satisfactorily.

  As described above, the manufacturing method of the display device (display panel) according to the present embodiment defines the pixel formation regions (the formation regions Rpx, Gpx,... Of the respective color pixels PXr, PXg,...) On the insulating substrate 11. After selectively forming a liquid repellent film made of the coating 18c of the triazine thiol compound on the surface of the bank 18 (bank metal portion 18b), the surface of the pixel electrode 15 is easily adapted to the hole transport material, and By selectively forming the base film 16x made of a material having non-acidity (non-oxidation characteristics), the phenomenon that the surface of the bank 18 is oxidized and etched when the base film 16x is formed is suppressed, and the surface of the bank 18 is While maintaining good liquid repellency, in the step of forming the hole transport layer 16a, the charge transport material-containing acidic liquid (polyethylenedioxythiophene / polyethylene dioxythiophene / containing the hole transport material on the pixel electrode 15). Polystyrene sulfonic acid aqueous solution PEDOT / PSS) can be uniformly applied.

  Therefore, the pixel electrode 15 exposed in the pixel formation region (the formation regions Rpx, Gpx,... Of the respective color pixels PXr, PXg,...) On the insulating substrate 11 is uniform over substantially the entire region without causing aggregation. Since the organic EL layer 16 (the hole transport layer 16a and the electron transporting light emitting layer 16b) having a film quality and a film thickness can be formed, the size of each display pixel (pixel formation region) is increased. In addition, the organic EL element can emit light uniformly over substantially the entire area of each pixel formation region, and a display panel having a high aperture ratio and excellent light emission characteristics can be realized.

In the above embodiment, the charge transport layer material contained in the base non-acid liquid and the charge transport layer material contained in the charge transport material-containing acidic liquid were both hole transport layer materials, but not limited thereto. The material may be an electron transport layer material.
In the above embodiment, the liquid-repellent film 18c is formed of a weakly acidic material such as a triazine thiol compound. However, the present invention is not limited to this, and the liquid-repellent film 18c is weak against alkalinity. When the material that forms the charge transport layer is dissolved or dispersed in an alkaline solvent or dispersion medium, a neutral or acidic base non-alkaline liquid is used instead of the base non-acid liquid, and the charge transport material-containing acidic An alkaline liquid containing an alkaline charge transport material may be used instead of the liquid.

  In the above-described embodiment, the structure in which the hole transport layer 16a and the electron transporting light emitting layer 16b are sequentially formed as the organic EL layer 16 has been described. However, the present invention is not limited thereto. The organic EL layer may be a single light emitting layer or a multilayer structure composed of a hole transport layer, a light emitting layer, and an electron transport layer, or may be composed of a hole transporting light emitting layer and an electron transport layer. In addition, other charge transport layers are added as appropriate, or the hole transport layer is controlled between the hole transport layer and the electron transporting light emitting layer to control the hole transport of the electron transporting light emitting layer. It may have a multilayer structure in which a charge transporting control layer for causing recombination of electrons and hole pairs at positions is interposed.

  In the above-described embodiments, the case where the display device and the manufacturing method thereof according to the present invention are applied to the display panel having the top emission structure has been described. However, the present invention is not limited to this, and the light emission driving is performed. By appropriately designing the layout of transistors, wiring layers, etc. that make up the circuit, it can be applied well to display panels having a bottom emission type light emitting structure that emits light toward the insulating substrate. it can. In the case of the bottom emission type, the planarization film 14 is not necessarily required, and the pixel electrode 15 may be formed on the protective insulating film 13 or the substrate 11.

  Specifically, for example, the transistors T1 and T2, the wiring layer LN, and the like are arranged in a region that overlaps the formation region of the bank 18 (bank metal portion 18b) in a plane (that is, a substantially lower layer region of the bank 18). The manufacturing method according to the present invention does not significantly reduce the aperture ratio of the display pixel PIX (display panel) even when light is emitted toward the insulating substrate 11 by performing the design layout. Is applied to emit light uniformly over a relatively wide area (substantially the entire area) of the pixel formation area (organic EL element formation area), thereby realizing a display panel with excellent light emission characteristics.

In the above embodiment, the pixel electrode 15 is an anode and the counter electrode 17 is a cathode. However, the pixel electrode 15 may be a cathode and the counter electrode 17 may be an anode.
Moreover, in the said embodiment, although the bank metal part 18b was utilized as a part of anode line La, you may apply to a part of cathode line Lc instead.

(Configuration example of pixel drive circuit)
FIG. 8 is an equivalent circuit diagram showing an example of display pixels (light emission drive circuits) two-dimensionally arranged on the display panel of the display device according to the present invention.
A display pixel PIX (color pixels PXr, PXg, PXb) applicable to the present invention includes, for example, a light emitting drive circuit including transistors T1, T2 provided on an insulating substrate 11, as shown in FIG. DC and organic EL element OEL are comprised. Various wiring layers LN including an anode line La, a cathode line Lc, a data line Ld, and a scanning line Ls directly or indirectly connected to the transistors T1 and T2 are provided, and a part of the transistors T1 and T2 and the wiring layer LN are provided. The protective insulating film 13 made of silicon nitride or the like and the planarizing film 14 made of photosensitive resin or the like are laminated so as to cover the film. A capacitor Cs is provided between the gate and the source of the transistor T2.

  In this configuration example, an n-channel transistor (that is, a transistor having a single channel polarity) is used as the light emission drive circuit DC provided in the display pixel PIX (color pixels PXr, PXg, PXb) constituting the display panel. ) A circuit configuration using T1 and T2 is shown. According to such a circuit configuration, since only an n-channel transistor can be applied, a transistor with stable operating characteristics can be easily manufactured using an amorphous silicon semiconductor manufacturing technology that has already been established. be able to. Here, the transistor of the light emission driving circuit may be a polysilicon TFT in addition to the amorphous silicon TFT. That is, only an n-channel transistor or a p-channel transistor may be provided, and both an n-channel transistor and a p-channel transistor may be provided. Moreover, you may comprise not only two but three or more transistors. The light emission driving circuit may perform voltage gradation control for controlling the luminance gradation of the organic EL element, and the luminance gradation of the organic EL element is controlled by supplying a current having a desired current value to the light emission driving circuit. It may be current gradation control.

It is a principal part schematic plan view which shows one Embodiment of the display apparatus (display panel) which concerns on this invention. It is a principal part schematic sectional drawing which shows one Embodiment of the display apparatus (display panel) which concerns on this invention. It is process sectional drawing (the 1) which shows an example of the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is process sectional drawing (the 2) which shows an example of the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is process sectional drawing (the 3) which shows an example of the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is process sectional drawing (the 4) which shows an example of the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is a chemical symbol which shows the molecular structure of the film material applied to the manufacturing method of the display apparatus (display panel) concerning this embodiment. FIG. 3 is an equivalent circuit diagram illustrating an example of display pixels (light emission drive circuits) two-dimensionally arranged on the display panel of the display device according to the present invention. It is a schematic sectional drawing which shows one structural example of an organic EL element. It is process sectional drawing (the 1) which shows an example of the manufacturing process of the display panel (organic EL element) in a prior art. It is process sectional drawing (the 2) which shows an example of the manufacturing process of the display panel (organic EL element) in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Insulating substrate 13 Protective insulating film 14 Flattening film 15 Pixel electrode 16 Organic EL layer 16x Underlayer film 16a Hole transport layer 16b Electron transport light emitting layer 17 Counter electrode 18 Bank 18b Bank metal part 18c Triazine thiol compound film 19 Sealing Stop resin layer 20 Sealing substrate T1, T2 Transistor La Anode line Lc Cathode line LN Wiring layer PIX Display pixel PXr, PXg, PXb Color pixel Rpx, Gpx color pixel formation region

Claims (7)

In a method for manufacturing a display device including a light emitting element having a charge transport layer,
A liquid repellent film forming step of forming a liquid repellent film on the surface of a plurality of partition walls provided on a substrate and at least the surface of which is a metal conductive layer;
A base film forming step of forming a base film by applying a base non-acidic liquid containing a charge transport layer material on the pixel electrode disposed between the plurality of partition walls;
A charge transport layer forming step of forming a charge transport layer together with the base film by applying a charge transport material-containing acidic liquid containing the charge transport layer material on the base film;
A method for manufacturing a display device, comprising:   2. The method for manufacturing a display device according to claim 1, wherein the liquid repellent film has a property that the liquid repellency is deteriorated by an acidic solution.   3. The display device manufacturing method according to claim 1, wherein the liquid repellent film includes a triazine thiol compound.   4. The method for manufacturing a display device according to claim 1, wherein the base film forming step includes a step of immersing the substrate in a base non-acidic liquid.   5. The method for manufacturing a display device according to claim 1, wherein the charge transport layer forming step includes a step of forming the charge transport layer by ejecting the charge transport material-containing acidic liquid in droplets. A display device manufacturing method comprising:   6. The method for manufacturing a display device according to claim 1, wherein the plurality of partition walls are wirings directly or indirectly connected to the light emitting element. 7. The method for manufacturing a display device according to claim 1, wherein the light emitting element is connected to a light emission driving circuit having a transistor.

Images