JP4366721B2 - Display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a display device and a manufacturing method thereof, and in particular, a display panel in which a plurality of display pixels each having a light emitting element on which a carrier transport layer is formed by applying a liquid material made of a carrier transport material is two-dimensionally arranged. The present invention relates to a display device provided and a manufacturing method thereof.

  In recent years, a display panel (organic EL display panel) in which organic electroluminescence elements (hereinafter abbreviated as “organic EL elements”) are two-dimensionally arranged is applied as a display device for electronic devices such as mobile phones and portable music players. It has been known. In particular, the organic EL display panel using the active matrix drive system has a faster display response speed, less viewing angle dependency, and higher brightness and higher contrast than the widely used liquid crystal display devices. In addition, the display image quality can be increased, and a backlight light guide plate or the like is not required unlike a liquid crystal display device, so that it has an extremely advantageous feature that it can be further reduced in thickness and weight. .

  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 during the bonding, but forms a hole transport layer (hole injection layer) and electron transporting light emitting layer (light emitting layer) that become the organic EL layer Depending on the organic material to be used (hole transport material or electron transporting light emitting material), 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, it is generally necessary to apply a vapor deposition method in the manufacturing process. Therefore, the low molecular organic film is selectively applied only on the anode electrode in the pixel formation region. When a thin film is formed, a mask for preventing the deposition of a low molecular material in a region other than the anode electrode may be used, and the low molecular material will adhere to the surface of the mask. In addition, the material loss is large and 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, an inkjet method (droplet discharge method), a nozzle print method (liquid flow discharge method), or the like can be applied as a wet film forming method. The organic material solution can be selectively applied on the anode electrode or only on a specific region including the anode electrode, and the organic EL layer (hole transporting) can be satisfactorily performed by an efficient manufacturing process with little material loss. Layer or an electron transporting light emitting layer) can be formed.

  In such a polymer organic EL display panel, a display pixel formation region (pixel formation region) arranged on an insulating substrate such as a glass substrate is defined, and 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 regions and a mixture of light emission colors (mixed color) occurs between display pixels when a liquid material (solution) is applied. One having a panel structure in which a partition wall formed by continuously projecting on an insulating substrate between formation regions is provided. 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 EL display panel as described above, an organic EL layer (a hole transport layer and an electron transport light emitting layer) is applied by applying a wet film forming method such as an ink jet method or a nozzle print method. When manufacturing a liquid crystal, the characteristics of the surface of each partition (anode electrode) to which the liquid material made of the organic material is applied and between the display pixels (pixel formation areas) (lyophilicity and repellent properties) are provided. Liquid), due to various factors such as surface tension and cohesive force caused by the solvent component of the above liquid material, light emitting materials of different colors are mixed in adjacent pixel formation areas, and the light emission color is mixed between display pixels (color mixing) ) And the film thickness of the organic EL layer formed in the pixel formation region (especially on the anode electrode) becomes non-uniform.

  For this reason, the light emission starting voltage at the time of the light emitting operation of the organic EL element and the wavelength of light emitted from the organic EL layer (that is, chromaticity at the time of image display) deviate from the design value, and a desired display image quality cannot be obtained. In particular, when a thin region is formed in the thickness of the organic EL layer, the emission driving current concentrates and flows there, so that the deterioration of the organic EL layer (organic EL element) becomes remarkable, and the reliability of the display panel There was a problem that the lifetime was reduced.

  Therefore, in view of the above-described problems, the present invention provides a display panel in which a carrier transport layer having a uniform film thickness is formed over substantially the entire area where each display pixel is formed without causing color mixing between adjacent display pixels. And a method for manufacturing the display device.

The invention according to claim 1 is a method of manufacturing a display device including a plurality of display pixels including an organic EL element having a pixel electrode, a carrier transport layer, and a counter electrode, wherein the pixel electrode has a conductive metal oxide surface. A base layer made of an inorganic insulating film between the adjacent pixel formation regions so as to surround the formation regions of the plurality of display pixels each having the pixel electrode provided on the substrate. forming a partition wall having at least a surface bank metal layer formed by non-oxidized metal material on the formation, by UV ozone treatment or oxygen plasma treatment, a step of lyophilic the pixel electrode surface, the pixel electrode A process of etching an oxide film on the surface of the bank metal layer of the partition wall formed in the step of making the surface of the pixel electrode lyophilic after the step of making the surface lyophilic If, after the step of etching the oxide film on the surface of the bank metal layer of the partition wall, said the the surface of the bank metal layer is bonded to the triazine thiol compound septum repellent surface of the bank metal layer of the partition wall Liquefying, and applying the solution containing the carrier transporting material on the lyophilic pixel electrode in the pixel formation region and drying to form the carrier transport layer. It is characterized by.

  According to a second aspect of the present invention, in the method for manufacturing a display device according to the first aspect, in the step of lyophilicizing the pixel electrode surface, at least the pixel electrode surface is transported to the carrier by UV ozone treatment or oxygen plasma treatment. It is characterized by being made lyophilic with respect to a solution containing a carrier transporting material forming a layer.

According to a third aspect of the present invention, in the manufacturing method of the display device according to the first aspect,
Process of lyophobic surface of the bank metal layer of the partition wall, the substrate was immersed in a solution of the triazine thiol compounds, said to bind the triazine thiol compound on the surface of the bank metal layer of the partition wall, the carrier A film having liquid repellency with respect to a solution containing a transportable material is formed.

In particular, in the method for manufacturing a display device according to claim 1 , the surface of the pixel electrode is formed of a conductive metal oxide layer.
The partition wall has a bank metal layer having at least a surface formed of a non-oxide metal material.

According to a fourth aspect of the present invention, in the method for manufacturing a display device according to any one of the first to third aspects, the formation region of the display pixel is defined by the partition wall.

According to a fifth aspect of the present invention, in the method for manufacturing a display device according to any one of the first to fourth aspects, the pixel electrodes of the plurality of display pixels are commonly opposed via the carrier transport layer, and Forming a single counter electrode extending and electrically connected on the liquid-repellent partition wall.
A display device according to a sixth aspect of the invention is manufactured by the method for manufacturing a display device according to any one of the first to fifth aspects.

  According to the display device and the manufacturing method thereof according to the present invention, an organic EL layer or the like having improved film thickness uniformity over substantially the entire formation region of each display pixel without causing color mixing between adjacent display pixels. It is possible to realize a display panel in which a carrier transport layer containing 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 embodiments described below, a case will be described in which an organic EL element including an organic EL layer made of the above-described polymer organic material is applied as a light-emitting element constituting a display pixel.

(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 display element and a pixel drive circuit). In the plan view shown in FIG. 1, for convenience of explanation, the arrangement of pixel electrodes and the arrangement of wiring layers provided in each display pixel (color pixel) when the display panel (insulating substrate) is viewed from the view side. In order to show only the relationship with the structure and drive the organic EL element (display element) of each display pixel to emit light, the display of the transistors and the like in the pixel driving circuit shown in FIG. 2 provided in each display pixel is omitted. In FIG. 1, hatching is shown for convenience in order to clarify the arrangement of the pixel electrode and each wiring layer.

  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 surface side of an insulating substrate 11 such as a glass substrate. A plurality of color pixels PXr, PXg, and PXb are repeatedly arranged in the horizontal direction of the drawing (multiple of 3), and a plurality of color pixels PXr, PXg, and PXb of the same color are arranged in the vertical direction of the drawing. Here, one display pixel PIX is formed by combining the adjacent RGB color pixels PXr, PXg, and PXb.

  The display panel 10 is projected by a common voltage line (for example, a cathode line) Lc having a bank (partition) shape that protrudes from one surface of the insulating substrate 11 and is arranged with a fence-like or grid-like plane pattern. Each color pixel area including a plurality of pixel pixels PXr, PXg, or PXb of the same color arranged in the vertical direction is defined. In addition, a pixel electrode (for example, an anode electrode) 15 is formed in each pixel formation region where a plurality of color pixels PXr, PXg, or PXb included in each color pixel region is formed, and the common voltage line Lc In parallel with the arrangement direction, the data line Ld is arranged in the vertical direction of the drawing (that is, the column direction), and the selection line Ls and the supply voltage line are orthogonal to the data line Ld in the horizontal direction of the drawing (that is, the row direction). (For example, an anode line) La is provided.

  As a specific circuit configuration of each color pixel PXr, PXg, and PXb of the display pixel PIX, for example, as shown in FIG. 2, a pixel drive composed of one to a plurality of transistors (for example, an amorphous silicon thin film transistor) on an insulating substrate 11 is performed. A circuit (or pixel circuit) DC, and an organic EL element (display element) OEL that emits light when a light emission drive current generated by the pixel drive circuit DC is supplied to the pixel electrode 15. .

  The supply voltage line La is directly or indirectly connected to, for example, a predetermined high potential power source, and is a pixel electrode 15 (for example, an anode electrode) of the organic EL element OEL provided in each display pixel PIX (color pixels PXr, PXg, PXb). A predetermined high voltage (supply voltage Vsc) for causing a light emission driving current to flow according to display data (gradation current Idata) is applied to the common voltage line Lc, for example, directly or indirectly to a predetermined low potential power source. A predetermined low voltage (common voltage Vcom; for example, ground potential Vgnd) is applied to the counter electrode (for example, cathode electrode) of the organic EL element OEL that is connected.

  For example, as shown in FIG. 2, the pixel driving circuit DC has a gate terminal connected to the selection line Ls arranged in the row direction of the display panel 10 (insulating substrate 11), a drain terminal connected to the supply voltage line La, a source Transistor Tr11 having a terminal connected to contact N11, a gate terminal connected to selection line Ls, a source terminal connected to data line Ld arranged in the column direction of display panel 10, and a drain terminal connected to contact N12. A transistor Tr12, a transistor Tr13 (light emission driving switching element) 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 between the contact N11 and the contact N12 (transistor And a capacitor Cs connected between the gate and source of Tr13. Here, n-channel thin film transistors are applied to all of the transistors Tr11 to Tr13. The thin film transistor may be an amorphous silicon thin film transistor or a polysilicon thin film transistor.

  The organic EL element OEL has an anode terminal (a pixel electrode 15 serving as an anode electrode) connected to the contact N12 of the pixel driving circuit DC and a cathode terminal (a counter electrode serving as a cathode electrode) arranged in the column direction of the display panel 10. Connected to the common voltage line Lc. In FIG. 2, a capacitor Cs is a parasitic capacitance formed between the gate and the source of the transistor Tr13 or an auxiliary capacitance additionally formed between the gate and the source.

  In the pixel drive circuit DC shown in FIG. 2, the selection line Ls is connected to a selection driver (not shown), and a plurality of display pixels PIX (color pixels) arranged in the row direction of the display panel 10 at a predetermined timing. A selection signal Ssel for setting PXr, PXg, PXb) to a selected state is applied from the selection driver. The supply voltage line La is connected to a power supply driver (not shown), and a predetermined supply voltage Vsc is applied from the power supply driver to the display pixels PIX arranged in the same row at a timing synchronized with the selection signal Ssel. The data line Ld is connected to a data driver (not shown), and a gradation current Idata corresponding to display data flows at a timing synchronized with the selection state of the display pixel PIX.

  The drive control operation in the display pixel PIX (display panel 10) including the pixel drive circuit DC having such a circuit configuration is first performed from the selection driver (not shown) to the selection line Ls in the writing operation period. Then, a selection signal Ssel of a selection level (on level; for example, high level) is applied, and a low-level supply voltage Vsc is supplied from a power supply driver (not shown) in synchronization with the selection signal Ssel as a supply voltage line (anode line) Apply to La.

  In synchronization with this timing, the data driver (not shown) controls the gradation current Idata having a current value corresponding to the display data to flow through the data line Ld. In other words, the data driver is a driver that controls the current value of the gradation current Idata according to the display data. In this embodiment, the data driver is set to the supply voltage Vsc that is a low level voltage fixed during the write operation period. On the other hand, it is assumed that the data driver lowers the potential of the data line Ld and flows the gradation current Idata having a desired current value in the direction of the data line Ld from the display pixel PIX (pixel drive circuit DC) side.

  As a result, the transistors Tr11 and Tr12 of the pixel drive circuit DC are turned on, and the low-level supply voltage Vsc is applied to the contact N11 (the gate terminal of the transistor Tr13; one end side of the capacitor Cs) and the gradation current Idata. The voltage level lower than the low-level supply voltage Vsc is applied to the contact N12 (source terminal of the transistor Tr13; the other end of the capacitor Cs) via the transistor Tr12 by the pull-in operation of the transistor Tr12. The set gradation current Idata is forced to flow.

  At this time, a charge corresponding to the potential difference generated between the contacts N11 and N12 is accumulated in the capacitor Cs and held (charged) as a voltage component. The amount of accumulated charge is automatically set by the current value of the gradation current Idata flowing between the drain and source of the transistor Tr13 during the write operation. At this time, the low-level supply voltage Vsc is set to be equal to or lower than the common potential Vcom (ground potential Vgnd) applied to the cathode terminal via the common voltage line (cathode line) Lc. Since no forward bias voltage is applied, no light emission drive current flows through the organic EL element OEL during the write operation, and no light emission operation is performed.

  Next, in the light emission operation period, a selection signal Ssel of a non-selection level (off level; for example, low level) is applied from the selection driver to the selection line Ls, and a high voltage is applied from the power supply driver to the supply voltage line La. A level supply voltage Vsc is applied. In synchronism with this timing, the operation of extracting the gradation current Idata by the data driver is stopped.

  As a result, the transistors Tr11 and Tr12 are turned off, the supply of the supply voltage Vsc to the contact N11 is cut off, and the application of the voltage level due to the drawing operation of the gradation current Idata to the contact N12 is cut off. Therefore, the capacitor Cs holds the charge accumulated in the write operation described above.

  In this manner, the capacitor Cs holds the charge (charge voltage) accumulated during the write operation, whereby the potential difference between the contacts N11 and N12 (between the gate and the source of the transistor Tr13) is held. A state is maintained in which Tr13 can flow a current having a current value corresponding to the current value of gradation current Idata. In addition, the supply voltage line La has a voltage level higher than the common voltage Vcom (ground potential Vgnd), and the drain-source potential difference is sufficiently high so that the current flowing through the transistor Tr13 becomes a saturation current during the light emission operation period. When the supply voltage Vsc having such a predetermined voltage value is applied, the transistor Tr13 has a current value of the gradation current Idata that flows during the writing operation due to the potential difference between the gate and the source due to the charge accumulated during the writing operation. A corresponding light emission drive current is passed through the organic EL element OEL in the forward bias direction, and the organic EL element OEL emits light at a luminance according to the gradation current Idata and thus the display data.

  Then, such a series of drive control operations are repeatedly performed, for example, for each row for all the display pixels PIX (each color pixel PXr, PXg, PXb) two-dimensionally arranged on the display panel 10 to obtain a desired An image display operation for displaying image information can be executed.

(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.
FIG. 3 is a plan layout view showing an example of a display pixel applicable to the display device (display panel) according to the present embodiment, and FIG. 4 is a detailed diagram of a main part of the planar layout of the display pixel according to the present embodiment. It is. 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. 3 mainly shows a layer in which each transistor and wiring layer of the pixel driving circuit DC are formed, and FIG. 4 shows a layer below the common voltage line Lc in the planar layout shown in FIG. Each transistor and wiring layer to be formed are specifically shown. In FIG. 4, the parenthesis numbers indicate the upper and lower order of each conductive layer (including the wiring layer). The smaller the number, the lower the layer side (insulating substrate 11 side). ). 5 and 6 are schematic cross-sectional views showing the AA cross section and the BB cross section of the display pixel PIX having the planar layout shown in FIG. 3, respectively.

  Specifically, the display pixels PIX (color pixels PXr, PXg, PXb) shown in FIG. 2 are pixel formation areas (formation areas of the respective color pixels PXr, PXg, PXb) set on one surface side of the insulating substrate 11. In Rpx, a selection line Ls and a supply voltage line La are provided so as to extend in the row direction (horizontal direction in the drawing) in the upper and lower edge regions of the planar layout shown in FIG. A data line Ld and a common voltage line Lc are arranged so as to extend in the column direction (vertical direction in the drawing) in the left and right edge regions of the planar layout so as to be orthogonal to Ls and La, respectively. .

  Here, as shown in FIGS. 3 to 6, the supply voltage line La is provided on the lower layer side (insulating substrate 11 side) than the common voltage line Lc, and the selection line Ls and the supply voltage line La are the same layer. The data line Ld is provided on the lower layer side than the selection line Ls and the supply voltage line La. Here, the selection line Ls is formed in the same process as the source and drain by patterning the source and drain metal layers for forming the source and drain of the transistors Tr11 to Tr13. The data line Ld is formed in the same process as the gate by patterning the gate metal layer for forming the gates of the transistors Tr11 to Tr13.

  That is, as shown in FIGS. 5 and 6, the display pixel PIX includes a plurality of transistors Tr <b> 11 to Tr <b> 13 and a capacitor Cs of a pixel driving circuit DC (see FIG. 2) provided in the display pixel PIX on the insulating substrate 11. Further, various wiring layers including the selection line Ls and the data line Ld are provided, and the upper layers thereof are provided via the protective insulating film 13 and the planarization film 14 which are sequentially formed so as to cover the transistors Tr11 to Tr13 and the wiring layer. Further, a pixel electrode (for example, an anode electrode) 15 connected to the pixel driving circuit DC and supplied with a predetermined light emission driving current, a hole transport layer 16a (carrier transport layer), and an electron transport light-emitting layer 16b (carrier transport layer). An organic EL element OEL composed of an organic EL layer (light-emitting functional layer) 16 and a counter electrode (for example, a cathode electrode) 17 to which a common voltage Vcom is applied. It has been made.

  More specifically, as shown in FIGS. 3 and 4, the pixel drive circuit DC is arranged so that the transistor Tr11 shown in FIG. 2 extends along the selection line Ls arranged in the row direction. The transistor Tr12 is arranged so as to extend along the data line Ld arranged in the column direction, and the transistor Tr13 is arranged so as to extend along the common voltage line Lc arranged in the column direction. Yes.

  Here, each of the transistors Tr11 to Tr13 has a well-known field effect transistor structure, and each of the gate electrodes Tr11g to Tr13g formed on the insulating substrate 11 and each of the gate electrodes Tr11g via the gate insulating film 12. And a semiconductor layer SMC formed in a region corresponding to .about.Tr13g, and source electrodes Tr11s to Tr13s and drain electrodes Tr11d to Tr13d formed so as to extend to both ends of the semiconductor layer SMC.

  A block 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 to Tr13 face each other. An impurity layer OHM for realizing ohmic connection between the semiconductor layer SMC and the source and drain electrodes is formed on the semiconductor layer SMC where the source electrode and the drain electrode are in contact. The gate electrodes Tr11g to Tr13g of the transistors Tr11 to Tr13 are all formed by patterning the same gate metal layer. The source electrodes Tr11s to Tr13s and the drain electrodes Tr11d to Tr13d of the transistors Tr11 to Tr13 are all formed by patterning the same source and drain metal layers.

  In order to correspond to the circuit configuration of the pixel drive circuit DC shown in FIG. 2, the transistor Tr11 has a contact hole HLa in which the gate electrode Tr11g is provided in the gate insulating film 12, as shown in FIGS. The source electrode Tr11s is connected to the electrode Eca on one end side (contact N11 side) of the capacitor Cs through the contact hole HLb provided in the gate insulating film 12, and the drain electrode Tr11d is connected to the selection line Ls. It is formed integrally with the supply voltage line La.

  3 to 5, the transistor Tr12 has a gate electrode Tr12g connected to the selection line Ls through a contact hole HLa provided in the gate insulating film 12, and the source electrode Tr12s is connected to the gate insulating film 12. The drain electrode Tr12d is integrally formed with the electrode Ecb on the other end side (the contact N12 side) of the capacitor Cs through a contact hole HLc provided in the capacitor Cs.

  In the transistor Tr13, as shown in FIGS. 3 to 5, the gate electrode Tr13g is integrally formed with the electrode Eca on one end side (contact N11 side) of the capacitor Cs, and the source electrode Tr13s is connected to the other end side of the capacitor Cs ( The drain electrode Tr13d is formed integrally with the supply voltage line La, and is formed integrally with the electrode Ecb on the contact N12 side.

In addition, the capacitor Cs includes an electrode Eca on one end formed integrally with the gate electrode Tr13g of the transistor Tr13 and an electrode Ecb formed on the other end integrally formed with the source electrode Tr13s. So as to extend opposite to each other.
As shown in FIGS. 3, 4, and 6, the selection line Ls extends on the gate insulating film 12 and is formed in the same layer as the supply voltage line (anode line) La.

  Further, as shown in FIG. 5, a contact hole HLd is formed in the protective insulating film 13 and the planarization film 14 on the source electrode Tr13s (electrode Ecb of the capacitor Cs) of the transistor Tr13, and the source electrode Tr13s and the organic EL A metal material (contact metal MTL) is embedded so as to be electrically connected to the pixel electrode 15 of the element OEL.

  Then, on the planarization film 14 in each pixel formation region Rpx, as shown in FIGS. 5 and 6, for example, an organic layer composed of a pixel electrode 15 serving as an anode electrode, a hole transporting layer 16 a and an electron transporting light emitting layer 16 b. An organic EL element in which an EL layer 16 and a counter electrode 17 serving as a cathode electrode are sequentially stacked is provided. Here, in this embodiment, the light emitted from the organic EL layer 16 is emitted from the side opposite to the insulating substrate 11 (through a sealing resin layer 19 and a sealing substrate 20 described later). A display panel (organic EL panel) having a light-emitting structure will be described. Therefore, the pixel electrode 15 has at least light reflection characteristics, and the counter electrode 17 has light transmittance. Here, the pixel electrode 15 has a laminated structure composed of the lower reflective metal layer 15a and the upper transparent conductive metal oxide layer 15b, as will be described later in the manufacturing method (see FIGS. 7 to 10). Have.

  Further, between the pixel formation regions Rpx in the column direction (boundary regions between the formation regions of the organic EL elements OEL of the display pixels PIX), the formation regions of the organic EL elements OEL (strictly speaking, the formation of the organic EL layer 16). A bank (partition wall) 18 for defining a region is provided so as to protrude from the upper surface of the planarization film 14. Here, in the present embodiment, the bank 18 extends in the column direction, for example, as shown in FIG. 5, and serves as an interlayer insulating film between the pixel formation regions Rpx. And an upper bank metal layer 18a that is a portion extending in the column direction of the common voltage line (cathode line) Lc.

  More specifically, the bank 18 extends from the planarization film 14 exposed in the vicinity of the boundary region between the display pixels PIX adjacent in the row direction to the peripheral edge in the column direction of the pixel electrode 15 of the organic EL element OEL. A base layer 18x made of a partially overlapping silicon nitride film (SiN) or the like is provided so as to extend in the column direction, and a bank metal layer 18a made of a conductive material (for example, a metal material) is formed on the base layer 18x. Are sequentially stacked so as to protrude in the thickness direction and extend in the column direction. As shown in FIG. 1, the ends of the plurality of base layers 18x and the bank metal layer 18a along the column direction are connected along the row direction outside the pixel formation region of the plurality of display pixels PIX.

  That is, a plurality of displays arranged in the column direction (vertical direction in the drawing) is provided by disposing the bank 18 having the laminated structure on the display panel 10 (insulating substrate 11) so as to have a fence-like planar pattern. A plurality of stripe-shaped pixel formation regions each having a pixel PIX are defined, and a predetermined number of pixels PIX (organic EL elements OEL) arranged in the entire area of the display panel 10 are defined by the bank metal layer 18a of the bank 18. Can be made to function as a wiring layer (common voltage line Lc) to which a common voltage (common voltage Vcom) can be applied in common.

That is, as shown in FIGS. 5 and 6, the counter electrode (cathode electrode) 17 of the organic EL element OEL extends on the bank 18 including the bank metal layer 18a and is electrically connected to the bank metal layer 18a. By forming them so as to be connected, the bank 18 (bank metal layer 18a) can also be used as the common voltage line Lc.
In addition, on the insulating substrate 11 on which the pixel driving circuit DC, the organic EL element OEL, and the bank 18 are formed, as shown in FIGS. 5 and 6, an insulating property is provided via a transparent sealing resin layer 19. A sealing substrate 20 made of a glass substrate or the like is bonded so as to face the substrate 11.

  In such a display panel 10, for example, functional elements such as transistors Tr11 to Tr13 and capacitors Cs provided in a lower layer of the display panel 10 (layer on the insulating substrate 11 side of the organic EL element OEL), a selection line, and the like. In the pixel driving circuit DC composed of wiring layers such as Ls, the data line Ld, and the supply voltage line (anode line) La, a predetermined current is determined based on the gradation current Idata corresponding to the display data supplied via the data line Ld. A light emission drive current having a current value flows between the drain and source of the transistor Tr13, and is supplied from the transistor Tr13 (source electrode Tr13s) to the pixel electrode 15 of the organic EL element OEL through the contact hole HLd (contact metal MTL). Thus, each display pixel PIX (each color pixel PXr, PXg , PXb) the organic EL element OEL emits light with a desired luminance gradation according to the display data.

  At this time, in the display panel 10 shown in this embodiment, when the pixel electrode 15 has a light reflection characteristic and the counter electrode 17 has a light transmission property (that is, when the organic EL element OEL is a top emission type). The light emitted from the organic EL layer 16 of each display pixel PIX (each color pixel PXr, PXg, PXb) is reflected directly through the counter electrode 17 having optical transparency or reflected by the pixel electrode 15 having light reflection characteristics. Then, the light is emitted to one side of the sealing substrate 20 (upward in FIGS. 5 and 6) without passing through the insulating substrate 11 (display panel).

  In this embodiment, the display element (organic EL element) having a top emission type light emitting structure has been described. However, the present invention is not limited to this, and the pixel electrode 15 having light transmittance, By applying the counter electrode 17 having the light reflection characteristic, the light emitted from the organic EL layer 16 is reflected directly or through the pixel electrode 15 having the light transmittance or by the counter electrode 17 having the light reflection characteristic. In addition, a display element having a bottom emission type light emitting structure that emits to the other surface side (downward in FIGS. 5 and 6) through the insulating substrate 11 (display panel) may be applied.

(Manufacturing method of display device)
Next, a method for manufacturing the above-described display device (display panel) will be described.
7 to 10 are process cross-sectional views illustrating an example of a method for manufacturing a display device (display panel) according to the present embodiment. Here, the manufacturing process of the panel structure seen from the AA cross section shown in FIG. 5 will be described. FIG. 11 is a conceptual diagram showing the chemical structural formula of the coating material on the bank surface formed in the display device (display panel) according to the present embodiment and the bonding in the state where the coating material is coated on the bank metal layer 18a. is there.

  In the manufacturing method of the display device (display panel) described above, first, as shown in FIG. 7A, display pixels PIX (each color) set on one surface side (the upper surface side of the drawing) of the insulating substrate 11 such as a glass substrate. In the pixel pixel PXr, PXg, PXb) formation region (pixel formation region) Rpx, the above-described pixel drive circuit (see FIGS. 2 to 4) DC transistors Tr11 to Tr13, capacitor Cs, data line Ld, selection line Ls, etc. A wiring layer is formed (see FIGS. 5 and 6).

  Specifically, the gate electrodes Tr11g to Tr13g, the electrode Eca on one side of the capacitor Cs formed integrally with the gate electrode Tr13g, and the data line Ld (see FIG. 5) on the insulating substrate 11 are the same. The gate metal layer is simultaneously formed by patterning, and then a gate insulating film 12 is formed over the entire insulating substrate 11.

  Next, a semiconductor layer SMC made of, for example, amorphous silicon or polysilicon is formed in regions corresponding to the gate electrodes Tr11g to Tr13g on the gate insulating film 12, and both sides of the block layer BL provided on the semiconductor layer SMC are formed. In addition, source electrodes Tr11s to Tr13s and drain electrodes Tr11d to Tr13d are formed through an impurity layer OHM for ohmic connection with the semiconductor layer SMC. At this time, by patterning the same source and drain metal layers, the electrode Ecb on the other side of the capacitor Cs connected to the source electrode Tr13s and the drain electrode Tr12d, the selection line Ls, and the drain electrodes Tr11d and Tr13d are connected. A supply voltage line La (see FIG. 6) is formed simultaneously.

  The source electrodes Tr11s to Tr13s and the drain electrodes Tr11d to Tr13d of the transistors Tr11 to Tr13, the electrode Ecb on the other end side of the capacitor Cs, the selection line Ls, and the supply voltage line La reduce wiring resistance and migrate. In order to reduce this, for example, it may have a laminated wiring structure composed of an aluminum alloy layer and a transition metal layer. Further, the transistors Tr11 to Tr13 are not limited to the inverted stagger type, but may be a coplanar type or the like.

  Next, as shown in FIG. 7B, a thickness of 50 nm to 100 nm is formed so as to cover the entire area of the one surface of the insulating substrate 11 including the transistors Tr11 to Tr13, the capacitor Cs, the selection line Ls, and the supply voltage line La. After sequentially forming a protective insulating film (passivation film) 13 made of silicon nitride (SiN) or the like and a planarizing film 14 made of a photosensitive organic resin material having a thickness of 1 μm to 10 μm, the planarizing film 14 and the protective insulating film 13 are formed. By patterning with light irradiation and etchant, a contact hole HLd is formed in which the upper surface of the source electrode Tr13s of the transistor Tr13 (or the electrode Ecb on the other side of the capacitor Cs) is exposed.

  Next, as shown in FIG. 7C, a contact metal MTL made of a metal material is embedded in the contact hole HLd. Here, as the contact metal MTL, for example, a thick film formed by depositing a metal material such as copper (Cu) using an electroless plating method or the like can be applied. Thereafter, as shown in FIG. 8A, the pixel electrode 15 electrically connected to the contact metal MTL is formed for each pixel formation region Rpx (the formation region of each color pixel PXr, PXg, PXb).

  Specifically, the pixel electrode 15 is a reflective metal having a light reflection characteristic made of a metal or an alloy containing at least one of aluminum (Al), chromium (Cr), silver (Ag), and palladium silver (AgPd). The film is formed into a thin film by sputtering or the like, and patterned into a predetermined shape, thereby forming a lower reflective metal layer 15a electrically connected to the contact metal MTL. Thereafter, it is made of a transparent electrode material such as tin-doped indium oxide (ITO) or zinc-doped indium oxide so as to cover the entire area of the one surface side of the insulating substrate 11 including the reflective metal layer 15a (light transmission characteristics). The upper conductive metal oxide layer 15b is formed by patterning so that the upper surface and the end surface of the reflective metal layer 15a are not exposed.

  As described above, when the upper metal oxide film is patterned, by preventing the lower reflective metal layer 15a from being exposed, a battery reaction due to the etchant is not caused between the metal oxide film and the reflective metal layer 15a. In addition, the reflective metal layer 15a on the lower layer side can be prevented from being over-etched or suffering from etching damage.

  Next, a chemical vapor deposition method (CVD method) or the like is used so as to cover the entire area of one surface side of the insulating substrate 11 including the pixel electrode 15 including the reflective metal layer 15a and the conductive metal oxide layer 15b, for example. An insulating layer made of an inorganic insulating material such as a silicon oxide film or a silicon nitride film is formed and then patterned to form display pixels PIX adjacent to each other in the row direction as shown in FIG. 8B. In a region between the pixel electrode 15 (boundary region with the adjacent display pixel PIX), a base layer 18x that is a lowermost layer of the bank 18 described later is formed along the column direction. The underlayer 18x has substantially the same shape as the supply voltage line Lc in FIG. 1, and is formed so that the pixel formation region of the display pixel PIX is opened in a plurality of stripe shapes.

  Next, as shown in FIG. 9A, on the base layer 18x, for example, copper (Cu), silver (Ag), aluminum (Al), or a low resistance such as a single metal or an alloy mainly composed of these. The bank metal layer 18a (supply voltage line Lc) made of the non-oxide metal material is formed so that the pixel formation region of the display pixel PIX is opened in a plurality of stripe shapes. If the surface of the bank metal layer 18a is a non-oxide metal material, the inside may contain a material other than the non-oxide metal material.

  Specifically, a thin film of the metal material is formed by using, for example, a sputtering method or a vacuum deposition method so as to cover the entire area of one surface side of the insulating substrate 11 including the base layer 18x, and a photolithography technique is used. Then, the bank metal layer 18a is formed by leaving the base layer 18x with a predetermined pattern. In the portion extending in the column direction, the bank metal layer 18a has a width in the row direction narrower than that of the base layer 18x so that the base layer 18x is exposed from both sides in the row direction. The underlayer 18x is an intervening layer for improving the adhesion between the planarization film 14 and the bank metal layer 18a, and the thermal expansion coefficient thereof is the same as that of the planarization film 14 and the bank metal layer. It is preferably between the thermal expansion coefficient of 18a.

  As a result, as shown in FIG. 1, the pixel formation region (the formation region of the organic EL layer 16 of the organic EL element OEL) Rpx of the plurality of display pixels PIX of the same color arranged in the column direction of the display panel 10 is changed to the bank metal. The bank 18 including the layer 18a and the base layer 18x is surrounded and defined, and the upper surface of the pixel electrode 15 (conductive metal oxide layer 15b) is exposed for each pixel formation region Rpx.

  Next, the insulating substrate 11 is washed with pure water, and then subjected to UV ozone treatment, oxygen plasma treatment or the like, thereby exposing the surface of the pixel electrode 15 (and the pixel exposed to each pixel formation region Rpx defined by the bank 18). Lyophilization of the underlying layer 18x exposed in the peripheral region of the electrode 15). A part of the surface of the bank metal layer 18a is oxidized during the lyophilic process, and the liquid repellent process described later cannot be performed on the surface of the bank metal layer 18a. The oxide film is removed. Next, the surface of the bank metal layer 18a from which the oxide film has been removed is selectively subjected to a liquid repellency treatment.

  Here, in the UV ozone treatment, which is an example of the lyophilic treatment of the pixel electrode 15, active oxygen radicals are generated by irradiating the insulating substrate 11 with ultraviolet light in an oxygen gas atmosphere, so that the pixel electrode 15 (conducting metal oxide layer made of ITO or the like), containing an organic compound-containing liquid containing a hole transporting material to be a hole transporting layer to be described later and an electron transporting light emitting material to be an electron transporting light emitting layer The liquid is made lyophilic (hydrophilic) so as to improve the wettability with respect to the organic compound-containing liquid or the organic solvent used in these solutions.

Further, the oxide film removal treatment is performed by immersing the insulating substrate 11 having the bank 18 formed on one side in an acid-based aqueous solution such as ammonium persulfate to soft-etch the surface of the bank metal layer 18a. After removing the oxide film, it is washed with pure water and dried. Next, the lyophobic treatment of the bank metal layer 18a is specifically performed by treating the insulating substrate 11 with a lyophobic solution of a triazine thiol compound such as triazine trithiol or a fluorinated triazine dithiol derivative containing fluorine in a functional group. Insert into the bath and immerse. In this treatment step, the temperature of the liquid repellent treatment solution is set to about 20 to 30 ° C., and the immersion time is set to about several tens of seconds to 10 minutes. Thereafter, the insulating substrate 11 is removed from the liquid repellent treatment solution, rinsed with alcohol or the like to wash away the liquid repellent treatment solution (triazine thiol compound) remaining on the surface of the insulating substrate 11, and the insulating substrate 11 is subjected to secondary cleaning with pure water. Then, it is dried by blowing nitrogen gas (N ₂ ).

  At this time, the triazine thiol compound is selectively combined with the metal on the surface of the bank metal layer 18a from which the oxide film has been removed by the oxide film removal treatment to form a film, but the metal oxide on the surface of the pixel electrode 15 is formed. The material (conductive metal oxide layer 15b) or the inorganic insulating film forming the base layer 18x is not coated to such an extent that it exhibits liquid repellency.

That is, a fluorine-based triazine dithiol derivative applicable as an example of a triazine thiol compound is a thiol group in nitrogen (—N) of triazine (six-membered ring structure containing three nitrogens) as shown in FIG. In addition to the molecular structure to which (—SH) is bonded, an alkyl group (—CH ₂ —CH ₂ —) and a fluorinated alkyl group (—CF ₂ —CF ₂ —CF ₂ ) are added to the S atom of a specific thiol group (—SH). In addition to triazine trithiol, which has a molecular structure in which —CF ₃ ) is sequentially bonded, and is similar to other triazine thiol compounds, as shown in FIG. Therefore, the coating film formed on the surface of the bank metal layer 18a exhibits stronger liquid repellency than triazine trithiol. The concentration of the liquid repellent treatment solution used in the treatment step described above is preferably in the range of approximately 1 × 10 ⁻⁴ to 1 × 10 ⁻² mol / L.

The fluorine-based triazine dithiol derivative has a molecular structure in which the S atom of the thiol group is bonded to the alkyl group (—CH ₂ —CH ₂ —), but may be directly bonded to the fluorinated alkyl group. In addition, there is no particular limitation on the number of carbon atoms of the alkyl group and the fluorinated alkyl group as long as the triazine thiol compound does not cause significant steric hindrance when the bank metal layer 18a is coated. Further, in the fluorine-based triazine dithiol derivative, in one S atom of the remaining two thiol groups, a fluorinated alkyl group may be substituted directly or indirectly in place of a hydrogen group, or contains a fluorine atom. Between the carbons of the group may have an olefin double bond. As other triazine thiol derivatives, for example, 6-dimethylamino-1,3,5-triazine-2,4-dithiol-sodium salt or 6-didodecylamino-1,3,5-triazine-2,4 -Dithiol-sodium salt may be used, and the film 18c may be coated by dissolving in water.

  Thereby, in each structure formed on the one surface side of the insulating substrate 11, on the surface of the bank metal layer 18a made of a metal material, the oxide film formed by the lyophilic process is removed by the oxide film removing process, Since the binding property with the triazine thiol compound is remarkably improved, the pixel electrode 15 covered with the metal oxide layer (ITO or the like) 15b is formed with a coating of the triazine thiol compound to the extent that the liquid repellency is sufficiently exhibited. The surface of the substrate and the surface of the underlying layer 18x and the planarizing film 14 (or the protective insulating film 13) exposed from between the pixel electrodes 15 are hardly attached, and a film is hardly formed. Therefore, on the same insulating substrate 11, only the surface of the bank metal layer 18a is subjected to the liquid repellent treatment, and the surface of the pixel electrode 15 exposed in each pixel formation region Rpx defined by the bank 18 is not subjected to the liquid repellent treatment. A state (a state in which lyophilicity is maintained) is realized.

  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. Further, “lyophilic” with respect to “liquid repellency” is defined as a state in which the contact angle is 40 ° or less in the present embodiment.

  Further, the pixel forming regions Rpx of the display pixels PIX (organic EL elements OEL) of the same color arranged in the column direction of the display panel 10 are adjacent to the display pixels PIX of other adjacent colors by the bank 18 subjected to the liquid repellent treatment. Since it is isolated from the pixel formation region Rpx of the (organic EL element OEL), when forming a light emitting layer (electron transporting light emitting layer 16b) to be an organic EL layer 16 described later, a solution or a dispersion of the light emitting material ( Even when the liquid material is applied, the light emitting material is not mixed with the display pixels PIX (color pixels PXr, PXg, and PXb) adjacent to each other beyond the bank 18, and the color mixture between the adjacent color pixels can be performed. Can be prevented.

  Next, as shown in FIG. 9B, a plurality of droplets separated from each other with respect to the pixel formation region (formation region of the organic EL element OEL) Rpx of each color surrounded (defined) by the bank 18. Apply the solution or dispersion of the hole transport material in the same process by applying the inkjet printing method or the nozzle printing method that continuously pours the solution, and then remove the residual solvent by heat drying. Then, the hole transport layer 16a is formed. Subsequently, as shown in FIG. 10A, a solution or dispersion of an electron transporting light emitting material is applied on the hole transporting layer 16a, and then the residual solvent is removed by heating and drying to form an electron transporting light emitting layer 16b. Form. Thus, an organic EL layer (light emitting functional layer) 16 composed of the hole transport layer 16a and the electron transport light emitting layer 16b is laminated on the pixel electrode 15.

  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). Oxythiophene PEDOT and a dispersion in which polystyrene sulfonate PSS as a dopant is dispersed in an aqueous solvent are applied on the pixel electrode 15 (conductive metal oxide layer 15b), and then the applied substrate 11 is placed. The organic polymer hole transport material is fixed on the pixel electrode 15 by performing a heat drying process on the stage and / or the atmosphere on the stage under a temperature condition of 100 ° C. or more to remove the residual solvent. Then, the hole transport layer 16a which is a carrier transport layer is formed.

  Here, since the surface of the pixel electrode 15 and the surrounding underlying layer 18x has lyophilicity with respect to the organic compound-containing liquid (PEDOT / PSS), the pixel formation region Rpx defined by the bank 18 is used. The organic compound-containing liquid applied to the liquid spreads evenly in the region (on the pixel electrode 15).

  Thus, as will be described later, when the organic compound-containing liquid is heat-dried, the organic compound-containing liquid is dried while being pulled toward the edge region, so that the hole transport layer 16a is formed on the center surface of the pixel electrode 15. Therefore, the film thickness is improved. Further, since the surface of the bank metal layer 18a has liquid repellency with respect to the organic compound-containing liquid (PEDOT / PSS), the leakage of the organic compound-containing liquid to the adjacent pixel formation region and overcoming it are prevented. can do.

  Further, as an organic compound-containing liquid containing an organic polymer-based electron-transporting light-emitting material (carrier-transporting material), for example, a light-emitting material containing a conjugated double bond polymer such as polyparaphenylene vinylene or polyfluorene is used as a water. Alternatively, after applying a solution dissolved in an organic solvent such as tetralin, tetramethylbenzene, mesitylene, and xylene on the hole transport layer 16a, the stage is heated in a nitrogen atmosphere or on a stage under a reduced pressure atmosphere of 1 Torr or less. The organic polymer electron-transporting light-emitting material is fixed on the hole transport layer 16a by heating and drying the atmosphere and removing the solvent, so that the electrons are the carrier transport layer and the light-emitting layer. The transporting light emitting layer 16b is formed.

  Also in this case, like the hole transport layer 16a described above, the surface of the hole transport layer 16a on the pixel electrode 15 and the surrounding underlying layer 18x are lyophilic with respect to the organic compound-containing liquid. Therefore, the organic compound-containing liquid applied to the pixel formation region Rpx defined by the bank 18 is sufficiently familiar and spread evenly within the region (on the hole transport layer 16a).

  Thus, as described later, when the organic compound-containing liquid is heat-dried, the organic compound-containing liquid is dried while being pulled in the direction of the edge region, so that the electron transport property formed on the hole transport layer 16a The film thickness uniformity of the light emitting layer 16b is improved. Moreover, since the surface of the bank metal layer 18a has liquid repellency with respect to the organic compound-containing liquid, it is possible to prevent the organic compound-containing liquid from leaking out and getting over the adjacent pixel formation region.

  Thereafter, as shown in FIG. 10B, a light-transmissive conductive layer (transparent electrode layer) is formed on the insulating substrate 11 including at least each pixel formation region Rpx, and the organic EL layer 16 (holes) is formed. A common counter electrode (for example, cathode electrode) 17 is formed to face each pixel electrode 15 via the transport layer 16a and the electron transport light emitting layer 16b). Here, the counter electrode 17 is formed by forming a thin film made of a metal material such as calcium (Ca), barium (Ba), magnesium, lithium fluoride, or the like, which becomes an electron injection layer by, for example, vacuum deposition or sputtering. A transparent film structure in the thickness direction in which a transparent electrode layer such as ITO is laminated on the upper layer by sputtering or the like can be applied.

  The counter electrode 17 is not only a region facing the pixel electrode 15 but also a single conductive layer extending to the bank 18 that defines each pixel formation region Rpx (formation region of the organic EL element OEL). It is formed and joined so as to be electrically connected to the bank metal layer 18 a forming the bank 18. Thereby, the bank metal layer 18a forming the bank 18 can be applied as a common voltage line (cathode line) Lc connected in common to each display pixel PIX. Thus, by covering the counter metal 17 and the equipotential bank metal layer 18a between the display pixels PIX (organic EL elements OEL), the sheet resistance of the entire cathode is lowered, and the display panel 10 as a whole has uniform display characteristics. can do.

  Next, after the counter electrode 17 is formed, a sealing layer 19 made of a silicon oxide film, a silicon nitride film, or the like is formed as a protective insulating film (passivation film) over the entire surface of the one surface side of the insulating substrate 11 using a CVD method or the like. Furthermore, the display panel 10 having the cross-sectional structure as shown in FIGS. 5 and 6 is obtained by bonding (bonding) the sealing lid and the sealing substrate 20 using UV curing or thermosetting adhesive. Is completed.

In the above-described embodiment, the case where the organic EL layer 16 includes the hole transport layer 16a and the electron transporting light emitting layer 16b has been described. However, the present invention is not limited to this, for example, hole transport. The electron-transporting light-emitting layer alone 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. .
In the above embodiment, the pixel electrode 15 is an anode. However, the present invention is not limited to this and may be a cathode. At this time, in the organic EL layer 16, the carrier transport layer in contact with the pixel electrode 15 may be an electron transport layer.

(Comparison verification)
Next, specific effects of the above-described display device manufacturing method according to the present invention will be specifically verified.
FIG. 12 is experimental data showing the relationship between the ultraviolet light irradiation time and the pure water contact angle in the UV ozone treatment, and FIG. 13 shows the soft etching treatment time after the lyophilic treatment and the pure water after the lyophobic treatment. It is an experimental data which shows the relationship with a contact angle. Here, FIGS. 12 (a) and 13 (a) are tables of numerical data obtained by each experiment, and FIGS. 12 (b) and 13 (b) are FIGS. 12 (a) and 13 (b). It is a graph of the numerical data shown in (a).

  In the above-described embodiment, the insulating substrate 11 in which the pixel formation region Rpx of each display pixel PIX (organic EL element OEL) is defined by the bank 18 arranged to protrude to the one surface side is subjected to UV ozone treatment or the like. After the lyophilic treatment, the surface of the bank 18 is immersed in an acid-based aqueous solution such as ammonium persulfate to perform soft etching, and then immersed in a liquid-repellent treatment solution such as a triazine thiol compound to form a triazine thiol compound on the bank surface. By forming a film and making it liquid repellent, a hydrophilic / hydrophobic pattern is formed on the insulating substrate 11 in which a region showing lyophilicity (pixel electrode surface) and a region showing liquid repellency (bank surface) coexist. The manufacturing method is shown.

  Here, as a method for forming the hydrophilic / hydrophobic pattern on the insulating substrate, in addition to the manufacturing method shown in the above-described embodiment, for example, the insulating substrate is immersed in a liquid-repellent treatment solution to make the bank surface liquid-repellent. Thereafter, a method of making the surface of the pixel electrode (conductive metal oxide layer) exposed to each pixel formation region lyophilic by UV ozone treatment or oxygen plasma treatment (hereinafter referred to as “first comparative example” for convenience) Conceivable.

  In such a manufacturing method, the liquid repellent coating (triazine thiol compound coating) formed on the bank surface that has been made liquid repellent in the previous step is decomposed by UV ozone treatment or oxygen plasma treatment during lyophilic treatment. As a result, the liquid repellency of the bank surface decreases, and when an organic compound-containing liquid is applied, light emitting materials of different colors are mixed in adjacent pixel formation regions (organic EL elements) to emit light between display pixels. There are problems such as color mixing (color mixing).

  As a technique for avoiding such a problem, for example, after making the pixel electrode of each pixel formation region lyophilic by UV ozone treatment or oxygen plasma treatment, the liquid repellent treatment solution is insulative without soft etching the bank surface. A manufacturing method (hereinafter referred to as “second comparative example” for the sake of convenience) in which a substrate is immersed to form a liquid-repellent film on the bank surface to make it liquid-repellent is considered.

  In this case, when copper, silver, or a low-resistance alloy containing these as a main component is applied as the metal material for forming the bank (or the bank surface), the surface of these metals by UV ozone treatment or oxygen plasma treatment, etc. Since the oxide film formed on the surface of the organic EL layer is not removed, it is difficult to form a liquid repellent film (triazine thiol compound film) in the subsequent liquid repellent treatment, or a counter electrode formed on the organic EL layer (for example, There is a problem that the contact resistance is increased due to a decrease in the bondability between the cathode electrode) and the bank. In particular, when copper, which is a low-resistance and relatively inexpensive, is applied as a metal material for forming a bank, it is more likely to be oxidized than when silver is applied, and the triazine thiol compound is extremely unlikely to be bonded in the lyophobic treatment. Therefore, the liquid repellency film is not sufficiently formed and the liquid repellency tends to be remarkably lowered.

  Here, in the first and second comparative examples, when copper is used as the metal material for forming the bank, and the pure water contact angle is measured when UV ozone treatment is applied as the lyophilic treatment, Table 1 shows As shown, in the first comparative example in which copper is immersed in a liquid repellent treatment solution of a triazine thiol compound to form a coating film to make the liquid repellent and then subjected to UV ozone treatment, the pure water contact angle is 73.2 °. In addition, in the second comparative example in which copper is subjected to UV ozone treatment and then immersed in a liquid repellent treatment solution without soft etching the bank surface, the pure water contact angle is 54.5 °. In any case, it was found that the pure water contact angle is relatively low and the liquid repellency is lowered.

  On the other hand, as shown in the above-described embodiment, when an organic compound-containing liquid such as PEDOT / PSS is applied as a material for the organic EL layer (hole transport layer) formed on the pixel electrode, It has the characteristics that it is easy to aggregate in the coating and drying process and the film thickness of the formed hole transport layer tends to be non-uniform. Here, in order to make the film thickness of the hole transport layer to which PEDOT / PSS is applied uniform, the pure water contact angle on the surface of the pixel electrode (conductive metal oxide layer) is set to approximately 10 ° or less. It is necessary to perform liquefaction treatment.

  Based on such a viewpoint, when the pure water contact angle for each processing step in the manufacturing method shown in the embodiment described above is verified, first, the ozone substrate is subjected to UV ozone treatment, and the pixel electrode (conductive In the process of making the surface of the metal oxide layer) lyophilic, as shown in FIG. 3, the longer the ultraviolet light irradiation time (UV irradiation time), the lower the pure water contact angle of the pixel electrode surface to 10 ° or less. It was found that the lyophilicity with respect to the above-mentioned PEDOT / PSS was improved.

  Here, the measurement of the pure water contact angle is, specifically, a UV ozone cleaner (model: NL-UV253) manufactured by Philgen Co., Ltd. is used as the lyophilic process, and the flow rate is 10 L / min as the oxygen injection condition. The injection time was set to 0.3 min, and an ITO film (conductive metal oxide layer) formed on the surface of the pixel electrode was subjected to UV ozone treatment.

  Thus, as a lyophilic treatment for the insulating substrate (pixel electrode having a conductive metal oxide layer made of an ITO film), pure water contact angle of 10 ° or less by irradiating with ultraviolet light for approximately 4 minutes (min) or longer. More preferably, it was found that a pure water contact angle of 10 ° or less can be stably obtained by irradiation for about 10 minutes (min).

  Next, after the UV ozone treatment, an insulating substrate is immersed in an aqueous solution of ammonium persulfate at a concentration of 1.0 wt% and set to a liquid temperature of about room temperature, and soft etching is performed. The oxide film formed on the surface of the copper forming the film is removed. Thereafter, the film is immersed in a liquid repellent treatment solution of a triazine thiol compound to form a liquid repellent film on the surface of copper forming the bank, and a liquid repellent treatment is performed. As shown in FIG. 13, the pure water contact angle on the bank (copper) surface in this case increases as the soft etching treatment time (immersion time in an aqueous solution of ammonium persulfate) becomes longer. In addition, compared with the pure water contact angle (73.2 °, 54.5 °) when the lyophobic treatment is performed without performing soft etching, 130 shows a sufficient lyophobic property against PEDOT / PSS. It was found to be set to about °.

Thus, as a soft etching performed prior to the liquid repellency treatment for the bank (copper) disposed on the insulating substrate, a pure water contact angle of about 130 ° is obtained by immersing in an aqueous ammonium persulfate solution for approximately 10 seconds or more. It was found that it can be obtained stably.
Further, as shown in FIG. 13, the pure contact angle of the surface of the pixel electrode (ITO film) after the liquid repellency treatment is substantially constant (approximately 9 to 11 °) regardless of the soft etching treatment time. Thus, it has been found that sufficient lyophilicity against PEDOT / PSS is maintained.

  As described above, in the insulating substrate (panel substrate) in which the formation region of each display pixel (organic EL element) is defined by the bank formed of the metal material, the parent of the pixel formation region (pixel electrode) by UV ozone treatment or the like. According to the manufacturing method in which a liquefaction treatment is performed and then the bank surface is soft etched and then a triazine thiol compound film is formed to make the liquid repellent, the purity of the surface of the pixel electrode (ITO film) exposed in the pixel formation region is reduced. A good lyophilic property can be realized by setting the water contact angle to approximately 10 ° or less, and a good liquid repellency is realized by setting the pure water contact angle on the bank surface defining the pixel formation region to approximately 130 ° or more. In the step of applying an organic compound-containing liquid (such as PEDOT / PSS) for forming an organic EL layer on an insulating substrate, An organic EL layer (light-emitting functional layer) in which the compound-containing liquid is sufficiently familiar and spreads over the entire area of the pixel electrode to form a uniform film thickness can be formed, and different colors are used for adjacent pixel formation regions (organic EL elements). It is possible to prevent a phenomenon in which a mixture of light emission colors (mixed color) occurs between display pixels due to mixing of the light emitting materials.

  In addition, since the oxide film formed on the bank surface by lyophilic treatment such as UV ozone treatment is removed by soft etching before the lyophobic treatment, it is common to each pixel formation region (pixel electrode) after the formation of the organic EL layer. As a result, the bonding property between the counter electrode and the bank can be improved, and good electrical connection can be realized.

  Accordingly, it is possible to suppress the deviation from the design value of the light emission starting voltage and the wavelength (chromaticity) of light emitted from the organic EL layer during the light emitting operation, and to obtain a desired display image quality. It is possible to realize a display panel with excellent reliability and lifetime by suppressing the occurrence of deterioration and poor connection.

  In the comparative verification described above, the case where the UV ozone treatment is applied as the lyophilic treatment of the pixel electrode has been described. However, the present invention is not limited to this, and in the plasma as in the UV ozone treatment. Even when lyophilic treatment is performed by oxygen plasma treatment in which oxygen radicals are generated to lyophilic (hydrophilize) the surface of the pixel electrode (conductive metal oxide layer made of ITO or the like), Equivalent results can be obtained and equivalent effects can be obtained.

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. 3 is an equivalent circuit diagram illustrating a circuit configuration example of each display pixel (display 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 embodiment. It is a principal part detail drawing of the planar layout of the display pixel which concerns on this embodiment. It is a schematic sectional drawing which shows the AA cross section in the display pixel which has the plane layout which concerns on this embodiment. It is a schematic sectional drawing which shows the BB cross section in the display pixel which has the planar layout which concerns on this embodiment. It is process sectional drawing (the 1) which shows an example of the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is process sectional drawing (the 2) which shows an example of the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is process sectional drawing (the 3) which shows an example of the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is process sectional drawing (the 4) which shows an example of the manufacturing method of the display apparatus (display panel) which concerns on this embodiment. It is a conceptual diagram which shows the coupling | bonding in the state which the chemical structural formula of the coating material of the bank surface formed in the display apparatus (display panel) concerning this embodiment, and the coating material coat | covered the bank metal layer. It is an experimental data which shows the relationship between the irradiation time of the ultraviolet light in UV ozone treatment, and a pure water contact angle. It is experimental data which shows the relationship between the processing time of the soft etching after a lyophilic process, and the pure water contact angle after a lyophobic process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display panel 11 Insulating substrate 15 Pixel electrode 15a Reflective metal layer 15b Conductive metal oxide layer 16 Organic EL layer 16a Hole transport layer 16b Electron transport light emitting layer 17 Counter electrode 18 Bank 18x Underlayer 18a Bank metal layer PIX Display pixel Rpx pixel formation area

Claims (6)

In a method for manufacturing a display device including a plurality of display pixels including an organic EL element having a pixel electrode, a carrier transport layer, and a counter electrode,
The pixel electrode has a surface formed of a conductive metal oxide layer,
A base layer made of an inorganic insulating film is provided between the adjacent pixel formation regions so as to surround the display pixel formation regions in which the pixel electrodes are provided on the substrate, respectively , and at least the surface is not on the base layer. forming a partition wall having a bank metal layer formed by a metal oxide material,
A step of making the pixel electrode surface lyophilic by UV ozone treatment or oxygen plasma treatment;
Etching the oxide film on the surface of the bank metal layer of the partition formed in the step of making the pixel electrode surface lyophilic after the step of making the pixel electrode surface lyophilic;
After the step of etching the oxide film on the surface of the bank metal layer of the partition wall, the the surface of the bank metal layer by bonding the triazine thiol compound of the partition wall, the surface of the bank metal layer of the partition wall lyophobic Process,
Applying the solution containing the carrier transporting material on the lyophilic pixel electrode in the pixel formation region and drying to form the carrier transport layer;
A method for manufacturing a display device, comprising: The step of lyophilicizing the pixel electrode surface is characterized in that at least the pixel electrode surface is made lyophilic with respect to a solution containing a carrier transporting material forming the carrier transport layer by UV ozone treatment or oxygen plasma treatment. A method for manufacturing a display device according to claim 1. Process of lyophobic surface of the bank metal layer of the partition wall, the substrate was immersed in a solution of the triazine thiol compounds, said to bind the triazine thiol compound on the surface of the bank metal layer of the partition wall, the carrier The method for manufacturing a display device according to claim 1, wherein a film having liquid repellency is formed on a solution containing a transportable material. The method for manufacturing a display device according to claim 1, wherein the display pixel formation region is defined by the partition wall. Forming a single counter electrode that is commonly opposed to the pixel electrodes of the plurality of display pixels via the carrier transport layer and that is electrically connected to extend on the liquid-repellent partition walls The method for manufacturing a display device according to claim 1, further comprising a step of: A display device manufactured by the method for manufacturing a display device according to claim 1.

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