JP4998710B2 - Manufacturing method of display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device comprising a display panel on which an excellent light-emitting functional layer (organic EL layer) is formed, and a manufacturing method of the display device. <P>SOLUTION: After a nozzle printing method or an ink-jet method or the like is applied to a pixel forming region Rpx (forming region of organic EL element OLED) of each color, and an organic compound-containing liquid to contain an organic polymer-based electron transport light-emitting material (carrier transport material) is coated on a positive hole transport layer 15a three times (plurality of times) by the same amount by heating a stage in nitrogen atmosphere by carrying out drying treatment, and by removing a remaining solvent, the organic polymer-based electron transport light-emitting material is fixed to the positive hole transport layer 15a, and an electron transport light-emitting layer 15b is formed which is a carrier transport layer and also a light-emitting layer. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

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 display elements are two-dimensionally arranged.

  2. Description of the Related Art In recent years, a display panel (organic EL display panel) in which organic electroluminescence elements (hereinafter abbreviated as “organic EL elements”), which are self-luminous elements, are two-dimensionally arranged as display devices for electronic devices such as mobile phones and portable music players. ) Is known. In particular, in an organic EL display panel to which an active matrix driving method is applied, the display response speed is faster and the viewing angle dependency is smaller than that of a widely used liquid crystal display device. Has the advantage that it is not necessary. Therefore, application to various electronic devices is expected in the future.

  Here, as is well known, for example, an organic EL element generally includes an anode (anode) electrode, an organic EL layer (light emitting functional layer), and a cathode (cathode) electrode sequentially on one side of a glass substrate or the like. It has a stacked element structure. By applying a positive voltage to the anode electrode and a negative voltage to the cathode electrode so as to exceed the light emission threshold, the holes and electrons injected in the organic EL layer are regenerated. Light (excitation light) is radiated based on the energy generated when bonding, depending on the organic material (hole transport material or electron transport material) that forms the carrier transport layer to be the organic EL layer, It can be roughly classified into low molecular weight and high molecular weight organic EL elements.

  In the case of an organic EL element to which a low molecular organic material is applied, since the vapor deposition method is generally applied in the manufacturing process, the low molecular organic film is selectively thinned only on the anode electrode in the pixel formation region. When forming, a mask is used to prevent the deposition of a low molecular material in a region other than the anode electrode, and the low molecular material adheres to the surface of the mask. In addition to the large material loss, the manufacturing process is inefficient.

  On the other hand, in the case of an organic EL element to which a polymer organic material is applied, in general, an inkjet method (droplet discharge method), a nozzle printing method (liquid flow discharge method), or the like can be applied as a wet film forming method. Therefore, the organic material solution can be selectively applied only on the anode electrode or only on a specific region including the anode electrode, and the organic EL layer (correction) can be accurately performed by an efficient manufacturing process with little material loss. A hole transport layer, an electron transport layer, a light emitting layer, etc.) can be formed.

  In such a polymer organic EL display panel, a formation region (pixel formation region) of each display pixel arranged on the insulating substrate is defined, and a liquid material containing a polymer organic material is used. In order to prevent a phenomenon in which light emitting materials of different colors are mixed in adjacent pixel formation areas when applying and light emission colors are mixed (mixed colors) between display pixels, an insulating substrate is formed between the pixel formation areas. What has the panel structure which provided the partition which protruded upwards and was formed continuously is known. The organic EL display panel provided with such a partition is described in detail in, for example, Patent Document 1 and the like.

JP 2001-76881 A (pages 4 to 7, FIGS. 1 to 6)

  However, in the polymer organic EL element as described above, an organic EL layer (a hole transport layer, an electron transport layer, a light emitting layer, etc.) is applied by applying a wet film forming method such as an ink jet method or a nozzle printing method. The characteristics of the surface of the partition provided between each pixel formation region and each display pixel (pixel formation region) to which the liquid material containing the organic material is applied during manufacture (lyophilicity or liquid repellency), Due to various factors such as surface tension and cohesive force caused by the solvent component of the liquid material (coating liquid), the light emitting materials of different colors are mixed in the adjacent pixel formation region and the light emission color is mixed (mixed color) between the display pixels. Or the film thickness of the organic EL layer formed in the pixel formation region becomes non-uniform.

  For this reason, the emission driving current concentrates and flows in the thin region of the organic EL layer, so that the deterioration of the organic EL layer (organic EL element) becomes remarkable, the reliability of the display panel is reduced, and the emission start voltage is reduced. However, there is a problem that the desired light emission luminance cannot be obtained and the display image quality of the display panel is deteriorated.

The present invention has been made in view of the above problems, and an object thereof is to provide a method of manufacturing a display device comprising a display panel having good light-emitting functional layer (organic EL layer) is formed.

According to a first aspect of the present invention, in the method of manufacturing a display device including a display panel in which a plurality of display pixels including a light emitting element having a carrier transport layer are arranged, the display pixels surrounded by a partition on the substrate are formed. When the organic solution containing the carrier transporting material is applied to the region in a continuous liquid flow by applying a plurality of times by the nozzle printing method , the applied organic solution is dried by heating after each application, and in the final round The amount of the organic solution to be applied is set to be smaller than the amount of the organic solution to be applied each time before that, and the organic solution is applied to the display pixel formation region so as to be in contact with the partition. After that, the display pixel is made so that the organic solution containing the same material as the carrier transporting material is made smaller in the final time than the coverage area of the carrier transporting layer by the organic solution applied in the previous time. Is applied to forming region, characterized in that it comprises a carrier transport layer forming step of forming the carrier transport layer.

The discharge rate of the organic solution per unit time of the nozzle that discharges the organic solution at each time is set to be the same, and the scanning speed of the nozzle or the substrate is placed so that the nozzle scans the display pixel formation region. It is characterized in that the scanning speed of the stage being set is set to be faster than the first application after the second application.

  According to the display device and the manufacturing method thereof according to the present invention, it is possible to realize a display panel in which a favorable light emitting functional layer (carrier transport layer; organic EL layer) is formed.

  Hereinafter, a display device and a manufacturing method thereof according to the present invention will be described in detail with reference to embodiments. Here, in the embodiment described below, a case where an organic EL element including an organic EL layer formed by applying an organic material is applied as a light emitting element constituting a display pixel will be described.

<First Embodiment>
(Display panel)
First, a display panel (organic EL panel) and display pixels applied to the display device according to the present invention will be described.

  FIG. 1 is a schematic plan view showing an example of a pixel arrangement state of a display panel applied to a display device according to the present invention, and FIG. 2 is a diagram of each two-dimensional array on the display panel of the display device according to the present invention. It is an equivalent circuit diagram which shows the circuit structural example of a display pixel (a light emitting element and a pixel drive circuit). In the plan view shown in FIG. 1, for convenience of explanation, pixel electrodes provided in each display pixel (color pixel) viewed from one surface side (organic EL element formation side) of the display panel (insulating substrate). Only the relationship between the arrangement of each wiring layer and the arrangement structure of each wiring layer and the arrangement relationship with the bank (partition) that defines the formation region of each display pixel are shown, and the organic EL element (light emitting element) of each display pixel emits light. In order to drive, the display of transistors and the like in the pixel driving circuit shown in FIG. 2 provided in each display pixel is omitted. Further, in FIG. 1, the pixel electrodes, the respective wiring layers, and the banks are hatched for the sake of convenience in order to clarify the arrangement.

  As shown in FIG. 1, the display device (display panel) according to the present invention has three colors of red (R), green (G), and blue (B) on one side of an insulating substrate 11 such as a glass substrate. A set of color pixels PXr, PXg, and PXb having the same color pixel PXr, PXg, and PXb of the same color in the column direction (vertical direction in the drawing) and a plurality of sets are repeatedly arranged in the row direction (horizontal direction in the drawing). Multiple sequences are arranged. Here, one display pixel PIX is formed by combining the adjacent RGB color pixels PXr, PXg, and PXb.

As shown in FIG. 1, the display panel 10 protrudes from one side of the insulating substrate 11 and is arranged in a column direction by banks (partition walls) 17 that are continuously arranged with a fence-like or grid-like plane pattern. A pixel formation region (each color pixel region) of a plurality of color pixels PXr, PXg, or PXb of the same color arranged in the same manner is defined. In addition, pixel electrodes (for example, anode electrodes) 14 are formed in the pixel formation region of each color pixel PXr, PXg, or PXb, and in the column direction (vertical direction in the drawing) in parallel with the arrangement direction of the bank 17. ), And a scanning line (selection line) Ls and a supply voltage line (for example, an anode line) La are parallel to each other in a row direction (horizontal direction in the drawing) orthogonal to the data line Ld. It is arranged.
Further, as will be described in detail later, the display panel 10 has a single electrode layer (a single electrode layer (so as to be commonly opposed to the pixel electrodes 14 of the plurality of display pixels PIX) two-dimensionally arranged on the insulating substrate 11). A counter electrode (for example, a cathode electrode) 16 made of a solid electrode is formed.

  As shown in FIG. 2, each color pixel PXr, PXg, PXb of the display pixel PIX includes a pixel driving circuit (or pixel circuit) DC having one or more transistors (for example, an amorphous silicon thin film transistor) on the insulating substrate 11. The light emitting driving current controlled by the pixel driving circuit DC is supplied to the pixel electrode 14 to have a circuit configuration including an organic EL element (light emitting element) OLED that emits light.

  Specifically, for example, as shown in FIG. 2, the pixel driving circuit DC has a gate terminal at the scanning line Ls, a drain terminal at the data line Ld arranged in the column direction of the display panel 10, and a source terminal at the contact point. A transistor (selection transistor) Tr11 connected to each of N11, a transistor (light emitting drive transistor) Tr12 having a gate terminal connected to the contact N11, a drain terminal connected to the supply voltage line La, and a source terminal connected to the contact N12; And a capacitor Cs connected between the gate terminal and the source terminal of the Tr12.

  Here, n-channel thin film transistors (field effect transistors) are applied to the transistors Tr11 and Tr12. If the transistors Tr11 and Tr12 are p-channel type, the source terminal and the drain terminal are opposite to each other. The capacitor Cs is a parasitic capacitance formed between the gate and the source of the transistor Tr12, an auxiliary capacitance additionally provided between the gate and the source, or a capacitance component composed of these parasitic capacitance and auxiliary capacitance. Yes (see FIG. 5).

  In the organic EL element OLED, the anode terminal (pixel electrode 14 serving as an anode electrode) is connected to the contact N12 of the pixel driving circuit DC, and the cathode terminal (cathode electrode) is formed by the single electrode layer described above. The common voltage line Lc formed integrally with the counter electrode 16 is connected.

  In the display pixel PIX (pixel drive circuit DC and organic EL element OLED) shown in FIG. 2, the scanning line Ls is connected to, for example, a scanning driver (not shown) and arranged in the row direction of the display panel 10 at a predetermined timing. A selection voltage (scanning signal) Ssel for setting the plurality of display pixels PIX (color pixels PXr, PXg, PXb) to a selected state is applied. The data line Ld is connected to a data driver (not shown), and a data voltage (grayscale signal) Vpix corresponding to display data is applied at a timing synchronized with the selection state of the display pixel PIX.

  The supply voltage line La is directly or indirectly connected to, for example, a predetermined high potential power source, and is a pixel electrode (for example, an anode electrode) of the organic EL element OLED provided in each display pixel PIX (color pixels PXr, PXg, PXb). ) A predetermined high voltage having a potential higher than the reference voltage Vss applied to the counter electrode 16 (for example, cathode electrode; common voltage line Lc) of the organic EL element OLED in order to flow a light emission driving current according to display data to 14) (Supply voltage Vdd) is applied, and the common voltage line Lc is connected to, for example, a predetermined low potential power source directly or indirectly, and all the display pixels PIX (organic) arranged two-dimensionally on the insulating substrate 11 A predetermined low voltage (reference voltage Vss; for example, ground potential) through the counter electrode 16 formed by a single electrode layer with respect to the cathode electrode of the EL element OLED) ND) is set to be commonly applied.

  That is, in each display pixel PIX, the supply voltage Vdd and the reference voltage Vss are applied to both ends (the drain terminal of the transistor Tr12 and the cathode terminal of the organic EL element OLED) of the pair of the transistor Tr12 and the organic EL element OLED connected in series. Then, a forward bias is applied to the organic EL element OLED so that the organic EL element OLED can emit light, and the current value of the light emission drive current that flows according to the gradation signal Vpix is controlled by the pixel drive circuit DC.

  In the drive control operation in the display pixel PIX having such a circuit configuration, first, a scanning level (on level; for example, high level) is applied to a scanning line Ls from a scanning driver (not shown) during a predetermined selection period. When the selection voltage Ssel is applied, the transistor Tr11 is turned on and set to the selected state. In synchronization with this timing, control is performed so that a gradation signal Vpix having a voltage value corresponding to display data is applied to the data line Ld from a data driver (not shown). As a result, a potential corresponding to the gradation signal Vpix is applied to the contact N11 (that is, the gate terminal of the transistor Tr12) via the transistor Tr11.

  In the pixel drive circuit DC having the circuit configuration shown in FIG. 2, the current value of the drain-source current of the transistor Tr12 (that is, the light emission drive current flowing through the organic EL element OLED) is the potential difference between the drain-source and the gate. -Determined by the potential difference between the sources. Here, since the supply voltage Vdd applied to the drain terminal (drain electrode) of the transistor Tr12 and the reference voltage Vss applied to the cathode terminal (cathode electrode) of the organic EL element OLED are fixed values, the drain of the transistor Tr12 The potential difference between the sources is fixed beforehand by the supply voltage Vdd and the reference voltage Vss. Since the potential difference between the gate and source of the transistor Tr12 is uniquely determined by the potential of the gradation signal Vpix, the current value of the current flowing between the drain and source of the transistor Tr12 is controlled by the gradation signal Vpix. be able to.

  As described above, the transistor Tr12 is turned on in a conductive state corresponding to the potential of the contact N11 (that is, a conductive state corresponding to the gradation signal Vpix), and the transistor Tr12 and the organic EL element OLED are supplied from the supply voltage Vdd on the high potential side. Since a light emission driving current having a predetermined current value flows through the reference voltage Vss (ground potential GND) on the low potential side through the organic EL element OLED, the luminance gradation corresponding to the gradation signal Vpix (that is, display data) The flash operates with. At this time, charges are accumulated (charged) in the capacitor Cs between the gate and the source of the transistor Tr12 based on the gradation signal Vpix applied to the contact N11.

  Next, in the non-selection period after the end of the selection period, by applying a selection voltage Ssel of a non-selection level (off level; for example, low level) to the scanning line Ls, the transistor Tr11 of the display pixel PIX is turned off and non-selected. The selected state is set, and the data line Ld and the pixel drive circuit DC are electrically disconnected. At this time, the charge accumulated in the capacitor Cs is held, so that the voltage corresponding to the gradation signal Vpix is held at the gate terminal of the transistor Tr12 (that is, the potential difference between the gate and the source is held). It becomes a state.

  Accordingly, similarly to the light emission operation in the selected state, a predetermined light emission drive current flows from the supply voltage Vdd to the organic EL element OLED via the transistor Tr12, and the light emission operation state is continued. This light emitting operation state is controlled so as to continue, for example, for one frame period until the next gradation signal Vpix is applied (written). Then, such a drive control operation is sequentially executed for every row, for example, for all the display pixels PIX (each color pixel PXr, PXg, PXb) two-dimensionally arranged on the display panel 10, thereby obtaining desired image information. An image display operation to be displayed can be executed.

  In FIG. 2, the pixel driving circuit DC provided in the display pixel PIX is written in each display pixel PIX (specifically, the gate terminal of the transistor Tr12 of the pixel driving circuit DC; the contact N11) according to display data. A voltage designation type gradation control method for controlling the current value of the light emission drive current to flow through the organic EL element OLED by adjusting (specifying) the voltage value of the gradation signal Vpix so that the light emission operation is performed at a desired luminance gradation. However, the current value of the light emission drive current that flows through the organic EL element OLED is controlled by adjusting (specifying) the current value to be written to each display pixel PIX according to the display data, so that the desired luminance can be obtained. It may have a circuit configuration of a current designation type gradation control system that performs light emission operation at gradation.

(Device structure of display pixel)
Next, a specific device structure (planar layout and cross-sectional structure) of the display pixel (light emission drive circuit and organic EL element) having the circuit configuration as described above will be described. Here, a display panel (organic EL panel) having a bottom emission type light emitting structure in which light emitted from the organic EL layer is emitted to the viewing side (the other side of the insulating substrate) through the insulating substrate will be described.

  FIG. 3 is a plan layout view showing an example of display pixels applicable to the display device (display panel) according to the present invention. Here, a planar layout of one specific color pixel among the red (R), green (G), and blue (B) color pixels PXr, PXg, and PXb of the display pixel PIX shown in FIG. 1 is shown. In FIG. 3, the layer in which each transistor, wiring, and the like of the pixel driving circuit DC are formed is mainly shown. 4A and 4B show the IVA-IVA line (in this specification, the Roman numeral “4” shown in FIG. 3) in the display pixel having the planar layout shown in FIG. For convenience, “IV” is used as a corresponding symbol. The same applies hereinafter) and a cross-sectional view taken along the line IVB-IVB.

  Specifically, the display pixels PIX (color pixels PXr, PXg, PXb) shown in FIG. 2 are pixel formation regions (organic EL elements in the color pixels PXr, PXg, PXb) set on one surface side of the insulating substrate 11. 4 (indicated as Rpx in FIG. 4), for example, the scanning line Ls and the supply voltage extend in the row direction (horizontal direction in the drawing) in the upper and lower edge regions of the planar layout as shown in FIG. Each line La is arranged, and the data line Ld is arranged so as to extend in the column direction (vertical direction in the drawing) in the left edge region of the planar layout so as to be orthogonal to the lines Ls and La. It is installed. A bank (detailed later) 17 is disposed in the right edge region of the planar layout so as to extend in the column direction across the color pixels adjacent to the right side.

  Here, for example, as shown in FIGS. 3, 4A, and 4B, the data line Ld is provided on the lower layer side (insulating substrate 11 side) than the scanning line Ls and the supply voltage line La, and the transistor By patterning the gate metal layer for forming the gate electrodes Tr11g and Tr12g of Tr11 and Tr12, the contact hole Ch1 is formed in the same process as the gate electrode and provided in the gate insulating film 12 formed thereon. To the drain electrode Tr11d of the transistor Tr11 formed integrally with the signal wiring layer Ldx.

  Further, the scanning line Ls is provided on the upper layer side than the data line Ld, and the source and drain metal layers for forming the source electrodes Tr11s and Tr12s and the drain electrodes Tr11d and Tr12d of the transistors Tr11 and Tr12 are patterned to pattern the scanning line Ls. It is formed in the same process as the source electrode and the drain electrode, and is connected to the gate electrode Tr11g through contact holes Ch2 provided in the gate insulating film 12 located at both ends of the gate electrode Tr11g of the transistor Tr11.

  Here, the scanning line Ls has, for example, a wiring structure in which a lower layer wiring portion Ls0 and an upper layer wiring portion Ls1 are stacked, and a supply voltage line La (including a power supply wiring layer La described later) is also connected to the lower layer wiring portion La0. It has a wiring structure in which an upper layer wiring portion La1 is laminated. The lower layer wiring portions Ls0 and La0 are both provided in the same layer as or integrally with the source electrode Tr12s and the drain electrode Tr12d of the transistor Tr12, and a source and drain metal layer for forming the source electrode Tr12s and the drain electrode Tr12d. Are simultaneously formed in the patterning step.

  The lower wiring portions Ls0 and La0 are respectively composed of a transition metal layer for reducing migration of chromium (Cr), titanium (Ti), etc., and an aluminum simple substance or an aluminum alloy provided on the transition metal layer. And a low-resistance metal layer for reducing the wiring resistance. The upper layer wiring portions Ls1 and La1 may be formed of a single layer of a low resistance metal for reducing wiring resistance such as aluminum alone or an aluminum alloy, or may be made of chromium (Cr) or titanium (Ti). You may have a laminated structure in which the said low resistance metal layer was provided on the transition metal layer for reducing migration.

  More specifically, for example, as shown in FIG. 3, the pixel driving circuit DC is connected to the scanning line Ls (or the data line Ld) in which the transistor Tr11 shown in FIG. The transistor Tr12 is disposed so as to extend along the signal wiring layer Ldx formed in the direction, and the transistor Tr12 extends along the power supply wiring layer Lay (or bank 17) formed so as to protrude from the supply voltage line La in the column direction. It is arranged to extend.

  Here, each of the transistors Tr11 and Tr12 has a well-known field effect type thin film transistor structure, and is formed in a region corresponding to each of the gate electrodes Tr11g and Tr12g via the gate electrodes Tr11g and Tr12g and the gate insulating film 12, respectively. And the source electrodes Tr11s and Tr12s and the drain electrodes Tr11d and Tr12d formed so as to extend to both ends of the semiconductor layer SMC.

  A channel protective layer BL such as silicon oxide or silicon nitride for preventing etching damage to the semiconductor layer SMC is formed on the semiconductor layer SMC where the source electrode and the drain electrode of the transistors Tr11 and Tr12 face each other. An impurity layer OHM for realizing ohmic connection between the semiconductor layer SMC and the source and drain electrodes is formed between the source and drain electrodes and the semiconductor layer SMC.

  Then, to correspond to the circuit configuration of the pixel driving circuit DC shown in FIG. 2, the transistor Tr11 scans through the contact hole Ch2 in which the gate electrode Tr11g is provided in the gate insulating film 12, as shown in FIG. The drain electrode Tr11d is connected to the line Ls and formed integrally with the signal wiring layer Ldx.

  3 and 4, the transistor Tr12 has a gate electrode Tr12g connected to the source electrode Tr11s of the transistor Tr11 through a contact hole Ch3 provided in the gate insulating film 12, and the drain electrode Tr12d is connected to the transistor Tr12. The source electrode Tr12s is directly connected to the pixel electrode 14 of the organic EL element OLED, connected to the power supply wiring layer La formed integrally with the supply voltage line La.

  As shown in FIGS. 3 and 4, the organic EL element OLED is provided on the gate insulating film 12 of the transistors Tr11 and Tr12, and is directly connected to the source electrode Tr12s of the transistor Tr12 so that a predetermined light emission drive current is generated. A pixel formation region Rpx (an organic compound described later) defined by a bank 17 disposed in the column direction on the insulating substrate 11 (set between the banks 17). An organic EL layer (light emitting functional layer) 15 composed of a hole transport layer 15a (carrier transport layer) and an electron transporting light emitting layer 15b (carrier transport layer) formed in the coating region of the containing liquid, and an insulating property A counter electrode 16 composed of a single electrode layer (solid electrode) provided in common to each display pixel PIX two-dimensionally arranged on the substrate 11 is sequentially laminated.

  Here, since the display panel 10 according to the present embodiment has a bottom emission type light emitting structure, the pixel electrode 14 is formed of a transparent electrode material such as ITO and has light transmission characteristics, and is opposed to the display panel 10. The electrode 16 has light reflection characteristics. The counter electrode 16 is provided so as to extend not only on each pixel formation region Rpx but also on the bank 17 that defines the pixel formation region Rpx.

  In the above-described structure, the scanning line Ls is formed by patterning the source and drain metal layers, the data line Ld is formed by patterning the gate metal layer, and is connected to the drain electrode and the gate electrode by the contact holes Ch1 and Ch2. However, the present invention is not limited to this, and the scan lines Ls are formed by patterning the gate metal layer, and the data lines Ld are formed by patterning the source and drain metal layers, thereby forming the contact holes Ch1 and Ch2. You may make it provide integrally with a gate electrode or a drain electrode, without providing.

  In addition, the supply voltage line La and the power supply wiring layer La are formed by layers different from the source and drain metal layers, but may be formed by patterning the source and drain metal layers. In this case, the supply voltage line La must be electrically insulated from other wirings formed by patterning the source and drain metal layers.

  The bank 17 is a boundary region between a plurality of display pixels PIX (each color pixel PXr, PXg, PXb) two-dimensionally arranged on the display panel 10, and extends in the column direction of the display panel 10 (the display panel 10 as a whole is shown in FIG. As shown in Fig. 2). Here, as shown in FIGS. 3 and 4A, the transistor Tr12 extends in the column direction of the display panel 10 (insulating substrate 11) in the boundary region. Insulating films 13a and 13b are formed so as to cover the transistor Tr12 and serve as an interlayer insulating film between the pixel electrodes 14 formed in each pixel formation region Rpx, and the bank 17 is insulated on the insulating films 13a and 13b. It is formed by laminating resin layers so as to protrude continuously from the surface of the conductive substrate 11. As a result, the region surrounded by the banks 17 extending in the column direction (pixel formation regions Rpx of the plurality of display pixels PIX arranged in the column direction (vertical direction in FIG. 1)) is formed in the organic EL layer 15 (holes). It is defined as an application region of an organic compound material when forming the transport layer 15a and the electron transporting light emitting layer 15b).

The bank 17 applied to this embodiment is subjected to a surface treatment so that at least the surface (side surface and upper surface) of the bank 17 has liquid repellency with respect to the organic compound-containing liquid applied to the pixel formation region Rpx. ing. The bank 17 is formed using, for example, a photosensitive resin material.
Note that one side of the insulating substrate 11 on which the pixel driving circuit DC, the organic EL element OLED, and the bank 17 are formed is sealed by bonding a metal cap, a sealing substrate, or the like (not shown). .

  In such a display panel 10, in the pixel driving circuit DC including functional elements such as the transistors Tr11 and Tr12, wiring layers such as the scanning line Ls, the data line Ld, and the supply voltage line (anode line) La, the data line Based on the gradation signal Vpix corresponding to the display data supplied via Ld, a light emission drive current having a predetermined current value flows between the source and drain of the transistor Tr12 and is supplied to the pixel electrode 14 of the organic EL element OLED. Thus, the organic EL element OLED of each display pixel PIX (each color pixel PXr, PXg, PXb) emits light with a desired luminance gradation corresponding to the display data.

  At this time, the display panel 10 shown in the present embodiment, that is, the pixel electrode 14 has light transmission characteristics and the counter electrode 16 has light reflection characteristics (that is, the organic EL element OLED is a bottom emission type). Therefore, the light emitted from the organic EL layer 15 of each display pixel PIX (each color pixel PXr, PXg, PXb) is directly transmitted through the pixel electrode 14 having light transmission characteristics or the counter electrode having light reflection characteristics. 16, passes through the insulating substrate 11 (display panel 10), and is emitted to the other surface side of the insulating substrate 11 that is the visual field side (downward in FIGS. 4 and 5).

(Manufacturing method of display device)
Next, a method for manufacturing a display device (display panel) according to the present invention will be described.
5 to 8 are process cross-sectional views illustrating a first embodiment of a method for manufacturing a display device (display panel) according to the present invention. Here, the cross section along the line IVA-IVA and the cross section along the line IVB-IVB shown in FIGS. 4A and 4B are divided into the right side and the left side of each of FIGS. Show. FIG. 9 is a conceptual diagram showing a coating process (coating scanning path) of the organic compound-containing liquid in the manufacturing method of the display device (display panel) according to the present embodiment, and FIG. 10 is a display according to the present embodiment. It is a conceptual diagram which shows the formation process of the organic electroluminescent layer (electron transport light emitting layer) in the manufacturing method of an apparatus (display panel). In FIG. 10, the illustration is simplified to conceptually show the step of applying the organic compound-containing liquid, and a cross-sectional structure in which pixel electrodes and insulating films are directly formed on an insulating substrate is shown for convenience. .

  In the manufacturing method of the display device (display panel) described above, first, as shown in FIGS. 5A to 5D, a display set on one surface side (the upper surface side of the drawing) of the insulating substrate 11 such as a glass substrate. For each pixel formation region Rpx of the pixel PIX (each color pixel PXr, PXg, PXb), the above-described pixel drive circuit (see FIGS. 2 and 3) DC transistors Tr11 and Tr12, data line Ld, signal wiring layer Ldx, scanning line A wiring layer such as a lower layer wiring portion Ls0 of Ls and a lower layer wiring portion La0 of the supply voltage line La is formed, and a pixel electrode 14 serving as an anode electrode of the organic EL element OLED is formed.

  Specifically, after forming a gate metal layer on the transparent insulating substrate 11, the gate electrodes Tr11g, Tr12g, and data are patterned by patterning the gate metal layer as shown in FIG. The line Ld is formed at the same time, and thereafter, the gate insulating film 12, the semiconductor film that becomes the semiconductor layer SMC made of amorphous silicon, and the insulating film such as silicon nitride that becomes the channel protective layer BL are continuously formed over the entire area of the insulating substrate 11. To do.

  Next, as shown in FIG. 5B, the insulating film and the semiconductor film are appropriately patterned, and the channel protective layer BL and the semiconductor layer SMC are sequentially formed in regions corresponding to the gate electrodes Tr11g and Tr12g on the gate insulating film 12. Form. Thereafter, impurity layers OHM for ohmic connection are formed at both ends of the semiconductor layer SMC.

  Next, as shown in FIG. 5C, on the gate insulating film 12 and in the substantially central region of the pixel formation region Rpx of each display pixel PIX (in the planar layout shown in FIG. Transparent electrode material such as tin-doped indium oxide (ITO) or zinc-doped indium oxide (IZO) having a rectangular planar pattern in the area (except for the periphery where wiring is arranged) A pixel electrode 14 made of (having light transmission characteristics) is formed. Thereafter, as shown in FIG. 3, contact holes Ch1, Ch2, and Ch3 are formed in the gate insulating film 12 so that the upper surfaces of the data line Ld and the gate electrodes Tr11g and Tr12g of the transistors Tr11 and Tr12 at predetermined positions are exposed. Form.

  Then, as shown in FIG. 5D, source electrodes Tr11s and Tr12s and drain electrodes Tr11d and Tr12d are formed at both ends of the semiconductor layer SMC of the transistors Tr11 and Tr12 via the impurity layer OHM. At the same time, the lower layer wiring portion Ls0 of the scanning line Ls, the lower layer wiring portion La0 of the supply voltage line La (including the power supply wiring layer Lay), and the signal wiring layer Ldx are simultaneously formed.

  Here, the source electrodes Tr11s and Tr12s, the drain electrodes Tr11d and Tr12d, the lower layer wiring portion Ls0 of the scanning line Ls, the lower layer wiring portion La0 of the supply voltage line La, and the signal wiring layer Ldx are formed after the step of FIG. After forming the drain metal layer, the drain metal layer is collectively formed by patterning. Thereby, the signal wiring layer Ldx is connected to the data line Ld located below via the contact hole Ch1, and the scanning line Ls is connected to the gate electrode Tr11g located below via the contact hole Ch2, Tr11s is connected to the gate electrode Tr12g located below via the contact hole Ch3. The other end side of the source electrode Tr12s of the transistor Tr12 extends to the pixel electrode 14 and is electrically connected.

  In addition, at least the source electrode Tr11s and drain electrode Tr11d of the transistor Tr11, the source electrode Tr12s and drain electrode Tr12d of the transistor Tr12, the lower layer wiring portion Ls0 of the scanning line Ls, and the supply voltage line La (including the power supply wiring layer Lay). The source and drain metal layers for forming the lower layer wiring portion La0 and the signal wiring layer Ldx are, for example, a lower layer metal layer made of chromium (Cr) alone or a chromium alloy, aluminum (Al) alone, or aluminum-titanium. It has a wiring structure in which an upper metal layer made of an aluminum alloy such as (AlTi) or aluminum-neodymium-titanium (AlNdTi) is laminated.

  Next, an inorganic insulating material such as silicon nitride (SiN) is formed so as to cover the entire area of one surface of the insulating substrate 11 including the transistors Tr11 and Tr12, the scanning line Ls, and the lower wiring portions Ls0 and La0 of the supply voltage line La. After forming the insulating film made of the material, the insulating film is patterned, and as shown in FIG. 6A, the upper surface of the lower wiring portion Ls0 of the scanning line Ls and the lower wiring portion La0 of the supply voltage line La, and Then, an insulating film 13a having an opening through which the upper surface of the pixel electrode 14 is exposed is formed.

  Next, on the insulating substrate 11 on which the insulating film 13a is formed, aluminum (Al) alone, aluminum-titanium (AlTi), aluminum-neodymium, for example, by sputtering, ion plating, vacuum deposition, plating, or the like. -After forming a low resistance metal layer (aluminum thin film) for reducing the wiring resistance such as aluminum alloy such as titanium (AlNdTi), by patterning, as shown in FIG. Upper layer wiring portions Ls1, La1 made of an aluminum thin film are formed only in a region corresponding to the planar pattern of the supply voltage line La (including the power supply wiring layer Lay). The upper layer wiring portions Ls1, La1 and the lower layer wiring portions Ls0, A scanning line Ls and a supply voltage line La (including a power supply wiring layer Lay) having a laminated wiring structure made of La0 are formed. It is.

  Next, an insulating film made of, for example, silicon nitride is used by using a chemical vapor deposition method (CVD method) or the like so as to cover the entire area of one surface side of the insulating substrate 11 including the scanning line Ls and the supply voltage line La. After the formation, the insulating film is patterned to cover the transistors Tr11 and Tr12, the scanning line Ls, and the supply voltage line La (including the power supply wiring layer Lay) as shown in FIG. An insulating film 13b having an opening through which the upper surface of the pixel electrode 14 of the display pixel PIX is exposed is formed.

  Next, as shown in FIG. 7A, a bank 17 made of a photosensitive resin material such as polyimide or acrylic is formed on the insulating film 13b formed in the boundary region between adjacent display pixels PIX. Form. Specifically, exposure and development are performed on a photosensitive resin layer formed to have a film thickness of, for example, 1 to 5 μm so as to cover the entire area of one surface side of the insulating substrate 11 including the insulating film 13b. By performing the processing, it has a fence-like or grid-like plane pattern (see FIG. 1) that includes a boundary region between display pixels PIX adjacent in the row direction and extending in the column direction of the display panel 10. Banks (partitions) 17 are formed. Here, as the resin material, for example, a polyimide coating material “Photo Nice PW-1030” manufactured by Toray Industries, Inc. can be favorably applied. Thereby, the pixel formation region Rpx (the formation region of the organic EL layer 15 of the organic EL element OLED) of the plurality of display pixels PIX of the same color arranged in the column direction of the display panel 10 is surrounded and defined by the bank 17. Then, the upper surface of the pixel electrode 14 whose outer edge is defined by the openings formed in the insulating films 13a and 13b is exposed (partition wall forming step).

  Next, after the insulating substrate 11 is washed with pure water, the pixel electrode 14 and the insulating film 13a exposed to each pixel formation region Rpx defined by the bank 17 by performing, for example, oxygen plasma treatment or UV ozone treatment. The surface of 13b is subjected to a lyophilic treatment with respect to the organic compound-containing liquid of the hole transport material or electron transporting light-emitting material used in the carrier transport layer forming step described later (lyophilic step).

  Next, the surface of the bank 17 is made liquid repellent with respect to the organic compound-containing liquid. Specifically, after the insulating substrate 11 is immersed in, for example, a fluorine-based (fluorine compound) lyophobic solution, the taken-out insulating substrate 11 is washed with alcohol or pure water and dried to form the surface of the bank 17. A liquid-repellent thin film (film) is formed. Here, when, for example, fluorinated alkylamine or the like is applied as the liquid repellent treatment solution, it does not react with the oxide film or the nitride film, and therefore a metal such as ITO or IZO on the surface of the pixel electrode 14 exposed in the pixel formation region Rpx. It is not formed on the surface of the oxide or the insulating films 13a and 13b, and retains the lyophilic property imparted by the above-described oxygen plasma treatment or UV ozone treatment.

  Thereby, on the same insulating substrate 11, only the surface of the bank 17 formed of the resin material is subjected to the liquid repellent treatment, and the surface of the pixel electrode 14 exposed to each pixel formation region Rpx defined by the bank 17 is A state where liquid repellency is not achieved (a state where lyophilicity is maintained) is realized.

  By defining the pixel formation region Rpx of each display pixel PIX (organic EL element OLED) by such a bank 17, the organic compound-containing liquid can be used by a nozzle printing method or an ink jet method in the carrier transport layer forming step described later. Even when the organic EL layer 15 is applied and the light emitting layer (electron transporting light emitting layer 15b) is formed, it is possible to prevent leakage and overcoming of the organic compound-containing liquid into the adjacent pixel formation region Rpx. It is possible to separate red, green, and blue while suppressing color mixing between adjacent pixels.

  Note that “liquid repellency” used in the present embodiment refers to an organic compound-containing liquid containing a hole transport material to be a hole transport layer, which will be described later, and an electron transport light-emitting material to be an electron transport light-emitting layer. When the 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 determined to be 50 ° or more. To do. In addition, “lyophilic” as opposed to “liquid repellency” is defined in the present embodiment as a state in which the contact angle is 40 ° or less, preferably 10 ° or less.

  Next, as shown in FIG. 7B, a nozzle printing (nozzle coating) method for discharging a continuous solution (liquid flow) to the pixel formation region Rpx (formation region of the organic EL element OLED) of each color, or Applying a solution or dispersion of a hole transport material in the same step by applying an inkjet method or the like that discharges a plurality of discrete droplets separated from each other in a predetermined position, and then drying by heating and drying the hole transport layer (Carrier transport layer) 15a is formed.

  Specifically, as an organic compound-containing liquid containing an organic polymer-based hole transport material (carrier transport material), for example, a polyethylene dioxythiophene / polystyrene sulfonic acid aqueous solution (PEDOT / PSS; polyethylene disulfide as a conductive polymer). After applying oxythiophene PEDOT and a dispersion of polystyrene sulfonate PSS, which is a dopant, in an aqueous solvent) on the pixel electrode 14, the stage on which the insulating substrate 11 is placed is heated to 100 ° C. or higher. By heating under temperature conditions and performing a drying treatment to remove the residual solvent, an organic polymer hole transport material is fixed on at least the pixel electrode 14, and the hole transport layer 15a as a carrier transport layer is formed. Form.

  Here, the upper surface of the pixel electrode 14 exposed in the pixel formation region Rpx and the surfaces of the insulating films 13a and 13b at the outer edges thereof are lyophilic with respect to the organic compound-containing liquid containing the hole transport material by the lyophilic process. Therefore, the organic compound-containing liquid applied to the pixel formation region Rpx defined by the bank 17 is in the pixel formation region Rpx (on the pixel electrode 14 and the insulating films 13a and 13b at the outer edges thereof). It spreads well enough. On the other hand, the bank 17 is set sufficiently high with respect to the height of the organic compound-containing liquid (PEDOT / PSS) to be applied, and has sufficient liquid repellency with respect to the organic compound-containing liquid. Therefore, it is possible to prevent the organic compound-containing liquid from leaking out and over to the adjacent pixel formation region Rpx.

  In the step of forming the hole transport layer 15a, for example, an organic compound-containing liquid containing a hole transport material is applied to the pixel formation regions Rpx of the plurality of display pixels PIX defined in the column direction of the insulating substrate 11. When applying the nozzle printing method for continuous application, as shown in FIG. 9, the nozzle of a nozzle printing machine (not shown) is reciprocated while scanning the insulating substrate 11 in the column direction (vertical direction in the drawing). The stage on which the nozzle or the insulating substrate 11 is placed is moved so that it is applied and applied to the pixel formation regions Rpx in different rows (adjacent rows) in the forward pass and the return pass (see arrows in the figure). Control.

  Next, as shown in FIG. 8A, a nozzle printing method, an ink jet method, or the like is applied to the pixel formation region Rpx (formation region of the organic EL element OLED) of each color, and the above-described hole transport layer 15a is formed. An electron transporting light emitting material solution or dispersion is applied to the substrate, and then heated and dried to form an electron transporting light emitting layer (carrier transport layer) 15b.

  Specifically, as an organic compound-containing liquid containing an organic polymer-based electron-transporting light-emitting material (carrier-transporting material), for example, red containing a conjugated double bond polymer such as polyparaphenylene vinylene-based or polyfluorene-based ( R), green (G), and blue (B) light emitting materials are appropriately dissolved in an aqueous solvent or an organic solvent such as tetralin, tetramethylbenzene, mesitylene, xylene, or the like to prepare a 0.1 wt% to 5 wt% solution. For example, as shown in FIGS. 10A to 10C, after applying the same amount (fixed amount) by 3 times (multiple times) on the hole transport layer 15a, the stage in a nitrogen atmosphere is applied. The organic solvent type electron transporting light emitting material is formed on the hole transporting layer 15a as shown in FIGS. 8 (a) and 10 (d) by heating and drying the material to remove the residual solvent. Fix the carrier transport layer There is also a light-emitting layer to form an electron transporting light emitting layer 15b.

  Here, the surface of the hole transport layer 15a formed in the pixel formation region Rpx is lyophilic with respect to the organic compound-containing liquid containing the electron transporting light-emitting material, and thus is defined by the bank 17. The organic compound-containing liquid applied to the pixel forming region Rpx spreads out sufficiently in the pixel forming region Rpx (on the hole transport layer 15a). On the other hand, the bank 17 is set sufficiently high with respect to the height of the organic compound-containing liquid to be applied and has sufficient liquid repellency with respect to the organic compound-containing liquid. It is possible to prevent the organic compound-containing liquid from leaking into and overcoming the formation region Rpx.

  In FIG. 10, for convenience of illustration, the organic compound-containing liquids EM11 to EM13 applied to the pixel formation region Rpx are shown as discontinuous droplets for convenience. However, when the nozzle printing method is applied. Is discharged in a continuous liquid flow. Further, in the first to third organic compound-containing liquid EM11 to EM13 application processes shown in FIGS. 10A to 10C, the nozzle printing machine is similar to the above-described formation process of the hole transport layer 15a. The nozzle NZL is reciprocated while being scanned in the direction perpendicular to the drawing (that is, the row direction of the insulating substrate 11 shown in FIGS. 1 and 9), and the forward path (for example, scanning from the top to the bottom in FIG. 9). In the pixel formation region Rpx in different columns (the next column in which the emission color becomes the same color pixel by forming the same material) on the return path (for example, the path in the scanning direction from bottom to top in FIG. 9). The movement of the stage on which the nozzle NZL or the insulating substrate 11 is placed is controlled so as to be applied.

  In the present embodiment, as shown in FIG. 9, the nozzle NZL is substantially constant with respect to the display pixel PIX (pixel formation region Rpx) in which the display panel 10 (insulating substrate 11) is two-dimensionally arranged. By sequentially repeating the forward scanning and the backward scanning for each column at the scanning speed, a coating process for one time is executed through a so-called one-stroke path. Accordingly, since the same operation is repeated at a constant cycle in the second and subsequent coating steps, the nozzle scanning direction with respect to each pixel formation region Rpx is always set to be constant, and the coating amount of the organic compound-containing liquid at each time Are set to be substantially the same, and the time interval between them is set to be substantially constant each time.

  In this case, when the volatile organic solvent such as xylene described above is used as the organic compound-containing liquid, the solvent applied up to the next coating step (for example, the second and third times) is volatilized and some natural drying is observed. However, it retains a liquid that is well mixed with the organic compound-containing liquid to be applied in the next application step.

  As shown in FIG. 1, in the display panel 10 in which display pixels PIX of three colors RGB (color pixels PXr, PXg, PXb) are arranged in the column direction for each color, and three colors of RGB are repeatedly arranged. Performs the coating operation for three colors by scanning the entire area of the insulating substrate 11 by repeating the forward scanning and the backward scanning every three rows of nozzles NZL for each color, and this operation is shown in FIG. ) To (c), the electron transporting light emitting layer 15b corresponding to each color of RGB is formed by repeating three times.

Here, the film thickness characteristic of the electron transporting light emitting layer 15b formed on the pixel electrode 14 of each display pixel PIX formed on the insulating substrate 11 will be examined in detail.
FIG. 11 is an example of experimental data for demonstrating the effect (uniform film thickness) in the formation process of the organic EL layer (electron transporting light emitting layer) according to the present embodiment. FIG. It is an example of the experimental data for demonstrating the effect (reduction of the variation in film thickness) in the formation process of the organic electroluminescent layer (electron transport light emitting layer) which concerns on this.

  Here, the above-mentioned organic material in which a red light emitting material is dissolved or dispersed in xylene (organic solvent) at a concentration of 2 wt% by applying a nozzle printing method on a single insulating substrate in which a pixel formation region is defined by a bank. As shown in FIG. 11 (a), the compound-containing liquid is applied to the same pixel twice in the same amount (applied twice), and the same amount is applied to the same pixel as shown in FIG. 11 (b). The film thickness of the light emitting layer in each pixel (pixel number) in the case of application (three times application) in three times was measured. In this case, the substrate temperature is 40 ° C., the discharge amount from the nozzle is 129.56 ± 0.94 μl / min, and the nozzle scanning speed is 1.5 m / s for the first application scan and 1.25 m for the second application scan. / S was set to 1.25 m / s in the third coating scan. Note that the total coating amount in the third coating is larger by one coating than the total coating amount in the second coating.

  In addition, the number of pixels in one column arranged on the insulating substrate is 100 pixels, the size of the application region in each display pixel (pixel formation region) is 370 × 55 μm, and the size of the measurement region in each display pixel (pixel formation region). After setting to 325 × 20 μm and continuously applying to all 100 pixels in each column, 50 pixels (that is, odd or even pixels) are extracted every other pixel in the column direction from the display pixels in each column. The film thickness of the light emitting layer in the measurement region in each display pixel was measured, and evaluation was performed by calculating a maximum value (thickest value), a minimum value (thinnest value), and an average value. That is, the pixel number on the horizontal axis in FIG. 11 is a value in the arrangement order of the pixels arranged along each column direction, and here, only the odd-numbered film thickness is shown.

  According to this, when the organic compound-containing liquid is applied twice to each pixel formation region, both the maximum value and the minimum value of the film thickness of the light emitting layer in the measurement region vary as shown in FIG. However, the variation in film thickness was suppressed compared to the case where the coating was applied once with the same total coating amount, and the difference between the maximum value and the minimum value with respect to the average value of the film thickness was within 5% of the film thickness. The display pixel was 66%, and the display pixel in which the difference between the maximum value and the minimum value with respect to the average value of the film thickness was within 2% of the film thickness was 0%.

  When the organic compound-containing liquid is applied three times to each pixel formation region, as shown in FIG. 11B, variations in both the maximum value and the minimum value of the thickness of the light emitting layer in the measurement region are significantly suppressed. Thus, the display pixel in which the difference between the maximum value and the minimum value with respect to the average value of the film thickness is within 5% of the film thickness is 100%, and similarly, the difference between the maximum value and the minimum value with respect to the average value of the film thickness is It was found that display pixels that were within 2% of the film thickness reached 88%.

  In addition, in order to verify the variation in the film thickness in the column direction in a single pixel, a specific display pixel (for example, the 49th pixel) on the insulating substrate is extracted, and a light emitting layer formed over substantially the entire measurement region. When the maximum value and the minimum value of the film thickness are measured and the variation (the difference in film thickness when the average film thickness is converted to 0) with respect to the average value (average film thickness) at each measurement position is verified, it is shown in FIG. In this way, the variation in film thickness is greatly suppressed (approximate average film thickness) in the case of coating three times (indicated by a solid line in the figure) compared to the case of twice coating (indicated by a dotted line in the figure). It was found to approximate the thickness).

  As described above, the same amount of the organic compound-containing liquid is applied a plurality of times (for example, three times) using a nozzle printing method or an ink jet method, and then subjected to a heat-drying process, so that it is substantially formed on the pixel electrode 14. An organic EL layer (light emitting functional layer) 15 including an electron transporting light emitting layer 15b having a uniform film thickness is formed (carrier transport layer forming step).

  Next, as shown in FIG. 8B, the insulating layer 11 on which the bank 17 and the organic EL layer 15 (the hole transport layer 15a and the electron transport light emitting layer 15b) are formed has light reflection characteristics. Then, a common counter electrode (for example, cathode electrode) 16 is formed to face each pixel electrode 14 via the organic EL layer 15 in each pixel formation region Rpx.

  Here, the counter electrode 16 is an electron having a low work function such as calcium (Ca), barium (Ba), lithium (Li), indium (In), etc. having a thickness of 1 to 10 nm by using, for example, a vacuum deposition method or a sputtering method. High work consisting of injection layer (cathode electrode) and aluminum (Al), chromium (Cr), silver (Ag), palladium silver (AgPd) based alloy having a thickness of 100 nm or more, or a transparent electrode such as ITO An electrode structure in which a thin film (feed electrode) of a function is laminated can be applied.

  As shown in FIGS. 1 and 4, the counter electrode 16 is not only a region facing the pixel electrode 14 in each pixel formation region Rpx (formation region of the organic EL element OLED), but also each pixel formation region. It is formed as a single conductive layer (solid electrode) extending to the bank 17 and the insulating films 13a and 13b that define Rpx (formation region of the organic EL element OLED) (counter electrode forming step).

  Next, after the counter electrode 16 is formed, a sealing layer 18 made of a silicon oxide film, a silicon nitride film, or the like is formed over the entire surface of the one surface of the insulating substrate 11 by using a CVD method or the like, as shown in FIG. A display panel 10 in which a plurality of display pixels PIX (organic EL elements OLED and pixel driving circuit DC) having such a cross-sectional structure (bottom emission type light emitting structure) are arranged in a matrix is completed. In addition to the sealing layer 18 or in place of the sealing layer 18, a sealing substrate such as a metal cap (sealing lid) or glass is bonded using a UV curing or thermosetting adhesive. It may be.

  As described above, according to the manufacturing method of the display device according to the present embodiment, in the step of applying the organic compound-containing liquid to be the light emitting layer, the same amount (a constant amount) or substantially the same amount is divided into a plurality of times from the nozzle. By discharging an equivalent amount of the organic compound-containing liquid, the organic compound-containing liquid is applied and applied to a wide area in the pixel formation region including at least the pixel electrode, and the electron-transporting light-emitting layer is a light-emitting layer. Can be flattened, so that the emission driving current flows in a concentrated manner in the thin region of the organic EL layer (hole transport layer and electron transporting light emitting layer). A display panel with excellent reliability and display image quality by suppressing the phenomenon that the EL element) is significantly deteriorated or the light emission start voltage changes (shifts) from the design value and the desired light emission luminance cannot be obtained. Can be offered .

Second Embodiment
Next, a second embodiment of the display device manufacturing method according to the present invention will be described. Here, since the pixel arrangement state of the display panel, the circuit configuration of each display pixel, and the planar layout are the same as those of the first embodiment described above, the second embodiment will be described with reference to FIGS. 1 to 9 as appropriate. Only the steps characteristic to the method of manufacturing the display device according to the present invention will be specifically described.

  In the first embodiment described above, as a method for flattening the electron-transporting light-emitting layer 15b, which is a light-emitting layer that defines the color of each display pixel PIX, the same amount is used by using a nozzle printing method or an inkjet method. Although the case where the organic compound-containing liquid is applied in a plurality of times and then the insulating substrate is heated and dried to form the light emitting layer has been described, in the present embodiment, organic printing is performed using a nozzle printing method or an inkjet method. The compound-containing liquid is applied in several batches, and each time it is heated and dried to form a thin film that is part of the light-emitting layer, and at least the organic compound-containing liquid that is applied at the final time is formed. The area covered by the thin film becomes narrower (smaller) than the area covered by the thin film formed by the organic compound-containing liquid applied in the previous round. And controlled so, it is characterized by forming a planarized light emitting layer (for example, an electron transport luminescent layer).

Specifically, one of the methods as shown below or a combination of two or more can be favorably applied to the method for forming the light emitting layer according to the present embodiment.
(1) Controlling the amount (application amount) of the organic compound-containing liquid to be applied in multiple times, the amount of organic compound-containing liquid to be applied in the last round contains the organic compound to be applied each time before that Set to be less than the amount of liquid.

(2) Controlling the temperature of the insulating substrate (strictly, the stage on which the insulating substrate is placed) when applying the organic compound-containing liquid in a plurality of times, and containing the organic compound applied in the final round The drying speed of the liquid is set to be faster than the drying speed in each previous time.
(3) The lyophilicity for a thin film formed by selecting an organic compound-containing liquid (light emitting material and organic solvent) having different lyophilicity (wetting properties) depending on the type of application surface and applying the organic compound-containing liquid. However, it is set to be smaller than the lyophilicity with respect to the insulating substrate or the underlying member (pixel electrode or hole transport layer).

Below, the formation method of the organic electroluminescent layer (electron transport light emitting layer) at the time of applying only the method of (1) among the methods of (1)-(3) mentioned above is demonstrated. Here, the description of the manufacturing method equivalent to that of the first embodiment described above is simplified or omitted.
FIG. 13 is a conceptual diagram showing an example of a process for forming an organic EL layer (electron transporting light emitting layer) in the method for manufacturing a display device (display panel) according to this embodiment. In FIG. 13, the illustration is simplified to conceptually show the step of applying the organic compound-containing liquid, and a cross-sectional structure in which pixel electrodes and insulating films are directly formed on an insulating substrate is shown for convenience. .

  In the manufacturing method of the display device according to the present embodiment, as in the first embodiment described above, first, the bank 17 is formed so as to continuously protrude from the surface of the insulating substrate 11, and each bank 17 forms each bank. A pixel formation region Rpx of the display pixel PIX is defined, and the insulating substrate 11 is subjected to oxygen plasma treatment or UV ozone treatment to make at least the upper surface of the pixel electrode 14 exposed in the pixel formation region Rpx lyophilic. Here, in the first embodiment described above, the case where the surface of the bank 17 is subjected to lyophobic treatment after the lyophilic process of the pixel electrode 14 has been described, but in this embodiment, the lyophobic process of the bank 17 is performed. Absent.

  Next, an organic compound-containing liquid containing a hole transport material is applied in the pixel formation region Rpx to form a hole transport layer 15a on at least the pixel electrode 14, and then, as shown in FIG. As a first coating step, a first amount of an organic compound-containing liquid EM21 containing an electron-transporting luminescent material is discharged from a nozzle (not shown), applied to the pixel formation region Rpx, and subjected to a heat drying process. As shown in FIG. 13B, a thin film FL21 of an electron transporting luminescent material is formed.

  The organic compound-containing liquid EM21 is centered by the surface tension of the organic compound-containing liquid EM21, the surface tension between the organic compound-containing liquid EM21 and the hole transport layer 15a, and the surface tension between the organic compound-containing liquid EM21 and the bank 17. A meniscus with a dent is formed. For this reason, the thin film FL21 dried and deposited in this state by the first coating process has a concave shape at the center. Here, the first amount is set to a relatively large amount such that the organic compound-containing liquid EM21 spreads in accordance with the entire area of the pixel formation region Rpx including the side surface of the bank 17, for example.

  As described above, the organic compound-containing liquid EM21 is sufficiently familiar and spreads thinly on the pixel electrode 14 in the pixel formation region Rpx via the hole transport layer 15a, and the organic compound-containing liquid EM21 is in contact with the bank 17 so as to contact these interfaces. The surface tension of the organic compound-containing liquid EM21 spreads so as to rise along the side of the bank 17 where the liquid-repellent treatment is not performed, so that the liquid level of the organic compound-containing liquid EM21 In the thin film FL21 having a surface step corresponding to the liquid level, the liquid level in the vicinity of the center of the pixel electrode 14 becomes relatively low due to the step on the surface of the insulating substrate 11 and the rise of both ends toward the side surface of the bank 17. Is formed.

  Next, as shown in FIG. 13C, a second amount of organic compound-containing liquid EM22 containing an electron-transporting light-emitting material is discharged from a nozzle (not shown) as a second coating step to thereby form a pixel formation region Rpx. The thin film FL22 of an electron transporting light emitting material is formed as shown in FIG. Here, the organic compound-containing liquid EM22 is the same solution as the first organic compound-containing liquid EM21, and the second amount is on the thin film FL21 as shown in FIGS. 13 (d) and 13 (e). The applied organic compound-containing liquid EM22 spreads, for example, in a region corresponding to the planar pattern of the pixel electrode 14, but both ends of the liquid surface do not contact or contact the side surface of the bank 17, and the organic compound-containing liquid The surface tension between the EM 21 and the bank 17 is set to a relatively small amount so that it does not become relatively large as compared with the first application.

  As a result, as shown in FIG. 13E, the second time is applied to the region corresponding to the pixel electrode 14 in the pixel formation region Rpx in which the surface step of the thin film FL21 based on the first coating step is formed to be relatively low. The organic compound-containing liquid EM21 applied in the coating step is sufficiently familiar and spreads, and the urge of the bank 17 is suppressed, and at least the region corresponding to the pixel electrode 14 in the pixel formation region Rpx (or the effect of the step difference due to the bank 17). Since the thin film FL22 is deposited so as to relieve the dent of the thin film FL21, the planarized thin film FL21 and the electron transporting light emitting layer 15b having a substantially uniform film thickness are formed. Is done.

  In this embodiment, as in the case shown in FIG. 10, the organic compound-containing liquids EM21 and EM22 applied to the pixel formation region Rpx are shown in the form of droplets for convenience of illustration. When the nozzle printing method is applied, the liquid is discharged in a liquid flow. In the first and second coating steps of the organic compound-containing liquids EM21 and EM22 shown in FIGS. 13A and 13C, the nozzle NZL is illustrated in the same manner as the hole transport layer 15a forming step described above. The pixel forming region is reciprocated while scanning in the vertical direction (that is, the column direction of the insulating substrate 11 shown in FIG. 1 and FIG. 9), and the column is different in the forward path and the backward path (the next column having the same color). The stage on which the nozzle or the insulating substrate 11 is placed is controlled to be applied to Rpx.

  Here, as a method of changing the amount (first and second amounts) of the first and second organic compound-containing liquids EM21 and EM22, in addition to a method of changing the discharge amount of the organic compound-containing liquid from the nozzle itself. In the coating process in the scanning path as shown in FIG. 9, the first and second amounts are arbitrarily controlled by changing the moving speed of the nozzle or stage (that is, the coating scanning speed). May be.

  Further, as shown in FIG. 1, in the display panel 10 in which display pixels PIX of three colors RGB (color pixels PXr, PXg, and PXb) are arranged in the column direction for each color, and three colors of RGB are repeatedly arranged. Performs the coating operation for three colors by scanning the entire area of the insulating substrate 11 by repeating the forward scanning and the backward scanning every three rows of nozzles for each color, and this operation is shown in FIG. , (C) is repeated twice to form the electron transporting light emitting layer 15b corresponding to each color of RGB.

  Thus, according to the method for manufacturing a display device according to the present embodiment, in the step of applying the organic compound-containing liquid to form the light-emitting layer (for example, the electron-transporting light-emitting layer), a plurality of organic compound-containing liquids are discharged from the nozzle. It is applied in batches, and each time it is heated and dried to form a thin film that becomes part of the light-emitting layer, and at least the amount of organic compound-containing liquid applied in the final round is adjusted to the previous round. The coating area of the thin film formed by the final coating is narrower (smaller) than the coating area of the thin film formed by the previous coating by reducing the amount of the organic compound-containing liquid applied to By controlling in such a manner, the entire thickness of the light emitting layer formed by laminating a plurality of thin films can be made uniform.

In addition, by sequentially laminating a plurality of thin films to be the light emitting layer, and controlling so that the coating area of each thin film changes, the effect of the step due to the bank protruding continuously on the insulating substrate is suppressed, The light emitting layer on the pixel electrode can be planarized.
Therefore, as in the first embodiment described above, the deterioration of the organic EL layer (organic EL element) due to the variation in the film thickness of the organic EL layer (hole transport layer and electron transporting light emitting layer) and the emission luminance. A display panel excellent in reliability and display image quality can be provided by suppressing the shift.
When the discharge amount of the organic compound-containing liquid per unit time at the nozzle is the same between the first application and the second application, the nozzle scanning speed may be increased after the second to reduce the application amount.

  In the above-described specific example, the method for forming the organic EL layer (electron transporting light-emitting layer) in the method (1) has been described. In the method (2), specifically, the organic compound is formed from the nozzle. When the containing liquid is applied in a plurality of times and a thin film that is a part of the light emitting layer is sequentially formed by heating and drying each time, at least the last time (2 in the coating process shown in FIG. 13). The temperature of the insulating substrate in the application process of the second time is set high so that it dries faster (for example, before reaching the bank side surface) than the liquid containing the organic compound in the previous application process. The coating area of the thin film formed by coating is controlled to be narrower (smaller) than the coating area of the thin film formed by previous coating.

Further, in the method (3), specifically, the organic compound-containing liquid is applied in a plurality of times from the nozzle, and a thin film that becomes a part of the light emitting layer is sequentially laminated by applying a heat drying process each time. When forming, the lyophilicity with respect to the organic compound-containing liquid in the hole transport layer 15a serving as the coating surface is greater than the lyophilicity with respect to the organic compound-containing liquid in the thin film formed by applying the organic compound-containing liquid. As described above, the light-emitting material and the organic solvent that constitute the organic compound-containing liquid are selected, and the spread of the organic compound-containing liquid in the application process of the last time (second time in the application process shown in FIG. 13) Control is performed so as to be narrower (smaller) than the coating area of the thin film formed by the coating process.
Also by the methods (2) and (3), the entire film thickness of a light emitting layer (for example, an electron transporting light emitting layer) formed by laminating a plurality of thin films can be made uniform.

  By the way, in the first and second embodiments described above, the bank 17 is formed so as to continuously protrude from the surface of the insulating substrate 11 so that the organic compound-containing liquid does not leak beyond the pixel formation region Rpx. Although the case where the organic compound-containing liquid is applied to the pixel formation region Rpx defined by the bank 17 has been described, the present invention is not limited to this, and each pixel formation region is defined without using a bank. Even in the case where a light emitting layer is formed by applying an organic compound-containing liquid to an insulating substrate, it can be applied satisfactorily. This will be specifically described below.

  FIG. 14 is a conceptual diagram illustrating another example of the formation process of the organic EL layer (electron transporting light emitting layer) in the method for manufacturing the display device (display panel) according to the present embodiment. In FIG. 14, the illustration is simplified to conceptually show the step of applying the organic compound-containing liquid, and a cross-sectional structure in which pixel electrodes and insulating films are directly formed on an insulating substrate is shown for convenience. .

  In the manufacturing method of the display device according to this example, first, as shown in FIG. 14A, a plurality of pixel electrodes 14 formed in a predetermined array (an array corresponding to the display pixel) on the insulating substrate 11. An insulating film 13 (corresponding to the above-described insulating films 13a and 13b) is formed between the adjacent display pixels, and at least the upper surface of the pixel electrode 14 exposed in the pixel formation region Rpx is formed with an organic compound-containing liquid. The surface of the insulating film 13 is made lyophobic with respect to the organic compound-containing liquid.

  Next, an organic compound-containing liquid containing a hole transport material is applied to the entire insulating substrate 11 including each pixel formation region Rpx to form a hole transport layer 15 a on at least the pixel electrode 14. At this time, since the organic compound-containing liquid is applied not only on the pixel electrode 14 but also on the insulating film 13, the hole transport layer 15 a is formed by the step between the pixel electrode 14 and the insulating film 13. Raised above. After that, as shown in FIG. 14A, a first amount of organic compound-containing liquid EM31 containing an electron-transporting light-emitting material is discharged as a first coating process, and the pixel formation region Rpx surrounded by the insulating film 13 is discharged. Then, a thin film FL31 of an electron transporting light emitting material is formed as shown in FIG. 14 (b).

  Here, since the hole transport layer 15a raised by the insulating film 13 formed between the display pixels PIX (pixel formation region Rpx) is relatively recessed on the pixel electrode 14, a first amount of the hole transport layer 15a is formed. The organic compound-containing liquid EM31 is also affected by the unevenness of the hole transport layer 15a, and the liquid level of the organic compound-containing liquid EM31 is relatively low in the region on the center of the pixel electrode 14 and corresponds to the liquid level. A thin film FL31 having a surface step is formed.

  Next, as shown in FIG. 14C, a second amount of organic compound-containing liquid EM32 containing an electron-transporting light-emitting material is discharged as a second coating step to form a pixel on the pixel electrode 14 in the pixel formation region Rpx. The thin film FL32 of an electron transporting luminescent material is formed as shown in FIG. Here, the organic compound-containing liquid EM32 is the same solution as the first organic compound-containing liquid EM31, and the second amount is on the thin film FL31 as shown in FIGS. 14 (d) and 14 (e). For example, the applied organic compound-containing liquid EM32 spreads in a region corresponding to the planar pattern of the pixel electrode 14, but both ends of the liquid surface do not spread over the insulating film 13 that defines the pixel formation region Rpx. It is set to a relatively small amount.

  As a result, as shown in FIG. 14E, the second time is applied to the region corresponding to the pixel electrode 14 in the pixel formation region Rpx in which the surface level difference of the thin film FL31 based on the first coating process is formed to be relatively low. The organic compound-containing liquid EM31 applied in the coating step is sufficiently familiar and spreads, and has a substantially uniform film thickness formed by laminating the thin film FL31 and the thin film FL32 at least in a region corresponding to the pixel electrode 14 in the pixel formation region Rpx The electron transporting light emitting layer 15b is formed.

As described above, according to the method for manufacturing a display device according to the present embodiment, as shown in each of the above-described embodiments, it is uniform on the pixel electrode without forming a bank protruding continuously on the insulating substrate. A light emitting layer (electron transporting light emitting layer) having a sufficient thickness can be formed.
Therefore, as in each of the above-described embodiments, deterioration of the organic EL layer (organic EL element) and deviation of emission luminance due to variations in the film thickness of the organic EL layer (hole transport layer and electron transporting light emitting layer) are prevented. It is possible to provide a display panel with excellent reliability and display image quality.

  In the manufacturing method of the display device shown in FIGS. 13 and 14, the case where the coating operation of the organic compound-containing liquid is performed twice has been described. However, the coating operation is performed three or more times. May be. In this case, what is necessary is just to control the thin film coating region formed in the final coating operation so as to be narrower (smaller) than the thin film coating region formed by the previous coating operation.

(Verification of effects by concrete experimental data)
Next, the effect of each embodiment described above will be verified by showing more specific experimental data.
In the first embodiment described above, one pixel is 240 pixels per line, the opening of the pixel electrode 14 in one pixel is 266.5 μm in length and 64 μm in width, and the oxygen plasma treatment is performed as the lyophilic treatment of the pixel electrode 14. The state of the 120th surface (center pixel) was measured by setting the total amount of the first, second, and third coatings to be the same. A 2.0 wt% xylene solution using a light emitting material containing a conjugated double bond polymer such as polyparaphenylene vinylene or polyfluorene was applied.

FIG. 15 is a graph obtained by measuring the level difference on the surface of the film that was applied three times or twice.
In the third coating, the coating scanning speed of the nozzle NZL is set to 2.5 m / sec, the heating temperature of the substrate 11 is set to 40 ° C., the total coating flow rate is set to 80.87 μl / min, and the flow rate variation (3σ value) is 1. It was 10 μl / min. As is apparent from FIG. 15, the unevenness of the film surface was the smallest.

  In the two-time coating, the coating scanning speed of the nozzle NZL is set to 1.5 m / sec, the heating temperature of the substrate 11 is set to 40 ° C., the total coating flow rate is set to 79.55 μl / min, and the flow rate variation (3σ value) is 1. It was 07 μl / min. The unevenness of the film surface was found to be slightly larger than that of the third coating.

FIG. 16 is a graph obtained by measuring the level difference on the surface of the single-coated film.
In one-time coating, the coating scanning speed of the nozzle NZL is set to 1 m / sec, the heating temperature of the substrate 11 is set to 40 ° C., the total coating flow rate is set to 79.12 μl / min, and the flow rate variation (3σ value) is 1.11 μl / min. min. One-time coating was thinner than two-time and third-time coatings, and a large variation was observed.

  FIG. 17 shows the measurement of the film thickness of the film surface of one pixel every six pixels out of 240 pixels in one line, and these measurements are performed on a plurality of lines. The average value is obtained. The display pixel in which the difference between the maximum value and the minimum value is within 5% of the film thickness is 100%, and the display pixel in which the difference between the maximum value and the minimum value with respect to the average film thickness is within 2% of the film thickness Was 77.5%, and the difference between the maximum value and the minimum value with respect to the average value of the film thickness was within 1.5% of the film thickness was 77.5%.

  FIG. 18 shows the measurement of the film thickness of the film surface of one pixel every six pixels out of 240 pixels in one line, and these measurements are performed on a plurality of lines. The average value is obtained. The display pixel in which the difference between the maximum value and the minimum value is within 5% of the film thickness is 100%, and the display pixel in which the difference between the maximum value and the minimum value with respect to the average film thickness is within 2% of the film thickness Was 72.5%, and the difference between the maximum value and the minimum value with respect to the average value of the film thickness was within 1.5% of the film thickness was 17.5%.

  In the second embodiment, one pixel is 240 pixels per line, the opening of the pixel electrode 14 in one pixel is 266.5 μm in length and 64 μm in width, and oxygen plasma treatment is performed as a lyophilic process for the pixel electrode 14. The variation in the film thickness in the horizontal direction in the second coating was measured. A 2.0 wt% xylene solution using a light emitting material containing a conjugated double bond polymer such as polyparaphenylene vinylene or polyfluorene was applied.

  In the second coating, the heating temperature of the substrate 11 is set to 40 ° C., the coating flow rate in the first coating is set to 84 to 86 μl / min, and the coating scanning speed of the nozzle NZL is set to 3.0 m / sec. The coating flow rate at 50 to 50 μl / min is less than the first time, and the coating scanning speed of the nozzle NZL increases from 1.0 m / sec every 0.2 m / sec to 11 patterns up to 3.0 m / sec. Set.

  FIG. 19 shows that the coating flow rate in the first coating is 84.66 μl / min, the flow rate variation (3σ value) is 1.37 μl / min, the coating flow rate in the second coating is 46.86 μl / min, This shows the variation in the film thickness in the horizontal direction of the pixel when the variation (3σ value) is 2.07 μl / min. The higher values on the left and right sides are the influence of the bank 17. Here, the film thickness in the pixel is between 68.75 nm where the film thickness is minimum (62.5 nm) and 110% of the minimum value (within + 10% from the minimum); The length in the horizontal direction that fits within the notation was 29 μm.

  FIG. 20 shows a case where the film thickness in each pixel is 110% of the minimum value to the minimum value (within + 10% from the minimum value) when the application scanning speed of the second nozzle NZL is modulated. ) Is a graph plotting the horizontal length of the pixels within the range, and the nozzle NZL coating scanning speed of 1.6 m / sec to 2.4 m / sec is the longest with the pixel horizontal length exceeding 28 μm. It was. FIG. 21 is a graph showing the height of the surface in the horizontal direction of the pixel when the application scanning speed of the second nozzle NZL is 1.2 m / sec, 2.2 m / sec, and 2.8 m / sec, respectively. is there. When the coating scanning speed of the second nozzle NZL is 1.4 m / sec or less, the coating scanning speed is slow (the coating amount is large), so that the amount of suction to the edge of the bank 17 is large, and the top of the bank 17 reaches the top. Riding is seen, and the center of the pixel has become thinner.

  When the coating scanning speed of the second nozzle NZL is 2.6 m / sec or more, the rate of drying before reaching the edge of the bank 17 increases, and a meniscus that protrudes slightly toward the center from the edge of the bank 17 is formed. Has been. It is considered that the flatness is lowered because the drying speed is fast and the sucking by the bank 17 is suppressed, and the coating scanning speed is fast (the coating amount is small).

  When the coating scanning speed of the second nozzle NZL is 1.4 m / sec or less, the film thickness is increased by increasing the heating temperature of the substrate 11 or using a low boiling point solvent to increase the drying speed. It is possible to improve the uniformity. That is, since it becomes easy to dry before sucking up to the top part of the bank 17 and the edge part of the bank 17, flatness can be improved.

  When the coating scanning speed of the second nozzle NZL is 2.6 m / sec or more, when the coating amount is small, the heating temperature of the substrate 11 is lowered, or a high boiling point solvent is used to slow down the drying speed, thereby reducing the film thickness. It is possible to improve the uniformity. That is, since the solution easily reaches the edge of the bank 17, the above-described meniscus formation can be suppressed and the flatness can be improved.

  In each of the above-described embodiments, the case where the organic EL layer is composed of a hole transport layer and an electron transporting light emitting layer has been described. However, the present invention is not limited to this. Only the transporting light emitting layer may be used, the hole transporting light emitting layer and the electron transporting layer may be used, or a carrier transporting layer may be appropriately interposed between them, or a combination of other carrier transporting layers may be used.

  And the manufacturing method of the display apparatus shown to each embodiment mentioned above is not limited to light emitting layers like an electron transporting light emitting layer, It is not limited to a hole transport layer, an electron transport layer, and other carrier transport layers. Also, it can be applied satisfactorily. Furthermore, the present invention is not limited to these organic EL layers (hole transport layer, electron transport layer, light emitting layer, etc.), but can be applied well when other organic films are formed by a wet film forming method in which an organic solution is applied. Can do.

In each of the above-described embodiments, the display panel having the bottom emission type light emitting structure has been described. However, the present invention is not limited to this, and the display panel may have a top emission type light emitting structure. Good. In this case, the pixel electrode may be formed of a conductive material having a light reflection characteristic such as aluminum or chromium, and the counter electrode may be formed of a conductive material having a light transmission characteristic such as ITO.
Furthermore, in each of the embodiments described above, the pixel electrode is an anode electrode, but the present invention is not limited to this and may be a cathode electrode. At this time, in the organic EL layer, the carrier transport layer in contact with the pixel electrode may be an electron transport layer.

It is a schematic plan view which shows an example of the pixel arrangement state of the display panel applied to the display apparatus which concerns on this invention. FIG. 6 is an equivalent circuit diagram illustrating a circuit configuration example of each display pixel (light emitting element and pixel driving circuit) two-dimensionally arranged on the display panel of the display device according to the present invention. It is a plane layout figure which shows an example of the display pixel applicable to the display apparatus (display panel) which concerns on this invention. It is a schematic sectional drawing in the display pixel which has the plane layout which concerns on this invention. It is process sectional drawing (the 1) which shows 1st Embodiment of the manufacturing method of the display apparatus (display panel) which concerns on this invention. It is process sectional drawing (the 2) which shows 1st Embodiment of the manufacturing method of the display apparatus (display panel) which concerns on this invention. It is process sectional drawing (the 3) which shows 1st Embodiment of the manufacturing method of the display apparatus (display panel) which concerns on this invention. It is process sectional drawing (the 4) which shows 1st Embodiment of the manufacturing method of the display apparatus (display panel) which concerns on this invention. It is a conceptual diagram which shows the application | coating process (application | coating scanning path | route) of the organic compound containing liquid in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is a conceptual diagram which shows the formation process of the organic electroluminescent layer (electron transport light emitting layer) in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is an example of the experimental data for demonstrating the effect (uniformity of a film thickness) in the formation process of the organic electroluminescent layer (electron transport light emitting layer) which concerns on this embodiment. It is an example of the experimental data for demonstrating the effect (reduction of the variation in film thickness) in the formation process of the organic EL layer (electron transport light emitting layer) according to the present embodiment. It is a conceptual diagram which shows an example of the formation process of the organic electroluminescent layer (electron transport light emitting layer) in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is a conceptual diagram which shows the other example of the formation process of the organic electroluminescent layer (electron transport light emitting layer) in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is an example of the experimental data which shows the level | step difference of the surface of the film | membrane of 3 times coating of the organic EL layer (electron transport light emitting layer) and 2 times coating in the manufacturing method of the display apparatus (display panel) concerning this embodiment. It is an example of the experimental data which shows the level | step difference of the film | membrane of the once coating of the organic EL layer (electron transport light emitting layer) in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is an example (the 1) of the experimental data which measured the film thickness of the surface of the film | membrane of each pixel in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is an example (the 2) of the experimental data which measured the film thickness of the surface of the film | membrane of each pixel in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is an example (the 1) of the experimental data which measured the height of the surface of the horizontal direction of one pixel in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is an example of the experimental data which measured the length of the part of the uniform film | membrane of the horizontal direction of one pixel in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is an example (the 2) of the experimental data which measured the height of the surface of the horizontal direction of one pixel in the manufacturing method of the display apparatus (display panel) which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display panel 11 Insulating substrate 13a, 13b Insulating film 14 Pixel electrode 15 Organic EL layer 15a Hole transport layer 15b Electron transport light emitting layer 16 Counter electrode 17 Bank PIX Display pixel Rpx Pixel formation area EM11-EM13, EM21-EM22, EM31-EM32 Organic compound-containing liquid FL21-FL22, FL31-FL32 thin film

Claims (2)

In a method for manufacturing a display device including a display panel in which a plurality of display pixels including a light emitting element having a carrier transport layer is arranged,
When an organic solution containing a carrier transporting material is applied in a continuous liquid flow multiple times by the nozzle printing method to the display pixel formation region surrounded by the partition on the substrate, it is applied after each application. The organic solution is dried by heating, and the amount of the organic solution applied in the final round is set to be smaller than the amount of the organic solution applied in each previous round, and the organic solution is After applying to the formation region of the display pixel so as to be in contact with the partition, an organic solution containing the same material as the carrier transporting material is coated in the last round, and the carrier transport layer is coated with the organic solution applied in the previous round. A method for manufacturing a display device, comprising: a carrier transport layer forming step of forming the carrier transport layer by applying to the display pixel formation region so as to be smaller than the region. The discharge rate of the organic solution per unit time of the nozzle that discharges the organic solution at each time is set to be the same, and the scanning speed of the nozzle or the substrate is placed so that the nozzle scans the display pixel formation region. 2. The method of manufacturing a display device according to claim 1, wherein the scanning speed of the stage being set is set to be faster after the second application than the first application.

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