JP4591837B2 - 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 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 layer functional material is two-dimensionally arranged. The present invention relates to a display device including a panel 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 to being able to increase the display image quality, it does not require a backlight, light guide plate, etc. unlike a liquid crystal display device, so it has a very advantageous feature that it can be made thinner and lighter. Yes.

  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 areas when a liquid material is applied, resulting in a mixture of light emission colors (mixed colors) between display pixels. Further, there is known a panel structure having a partition wall which protrudes on an insulating substrate and is continuously formed. 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 and an electron transport light emitting layer) is manufactured by applying a wet film forming method such as an ink jet method or a nozzle print method. In this case, the surface characteristics (lyophilicity and liquid repellency) of the partition walls provided between each pixel formation region and each display pixel (pixel formation region) to which the liquid material made of the organic material is applied, the liquid material Due to various factors such as surface tension and cohesive force caused by the solvent component of the (coating liquid), light emitting materials of different colors are mixed in adjacent pixel formation regions, resulting in mixing of light emission colors (color mixing) between display pixels. Or the film thickness of the organic EL layer formed in the pixel formation region 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. If the area of the organic EL layer is thin, especially when the organic EL layer is thin, the light emission drive current concentrates and flows there, so that the deterioration of the organic EL layer (organic EL element) becomes significant, and the reliability and life of the display panel Had the problem of lowering.

  Therefore, in view of the above-described problems, the present invention provides a display device including a display panel in which a light emitting functional layer (organic EL layer) having a uniform film thickness is formed over substantially the entire formation region of each display pixel, and An object of the present invention is to provide 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 a light emitting element having a carrier transport layer.
Forming a partition wall with a polyimide-based resin material between the formation regions of the plurality of display pixels each provided with a pixel electrode on a substrate;
Oxygen plasma treatment or UV ozone treatment is performed to make the surface of the pixel electrode lyophilic with respect to an organic solution containing a carrier transporting material, and at the same time, the imide ring on the surface of the partition wall is opened to generate a carboxyl group And modifying the process,
Immersing the partition in a solution of fluorinated alkylamine , binding the fluorinated alkylamine to a carboxyl group on the surface of the partition, and making the organic solution containing the carrier transporting material liquid repellent; It is characterized by including.

As described above, the step of making the surface of the pixel electrode lyophilic is made lyophilic with respect to the organic solution containing the carrier transporting material by performing oxygen plasma treatment or UV ozone treatment on the surface of the pixel electrode. It is characterized by that.
The step of lyophobic the surface of the partition wall includes immersing the partition wall in a solution of fluorinated alkylamine, and bonding the fluorinated alkylamine to the modified surface of the partition wall, thereby transporting the carrier. It is characterized by repelling an organic solution containing the material.

According to a second aspect of the present invention, in the method for manufacturing a display device according to the first aspect , the fluorinated alkylamine solution is an aqueous solution of the fluorinated alkylamine containing hydrochloric acid .

According to a third aspect of the present invention, in the method for manufacturing a display device according to the first or second aspect , the partition wall is formed of a silicon nitride film or a silicon oxide film formed on the substrate between the display pixel formation regions. It is formed on an insulating layer.
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, an organic solution containing the carrier transporting material is applied and dried on the lyophilic pixel electrode. A step of forming the carrier transporting layer, and facing the pixel electrodes of the plurality of display pixels in common through the carrier transporting layer and extending on the liquid-repellent partition walls. And a step of forming a single counter electrode formed on the substrate.
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, the light emitting functional layer (carrier transport layer; organic EL layer) with improved film thickness uniformity is formed over substantially the entire formation region of each display pixel. A display panel can be realized.

  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 will be described in which an organic EL element including an organic EL layer having a polymer organic material described above 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 drive only the organic EL elements (light emitting elements) 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 protrudes from one side of the insulating substrate 11 and is arranged in the vertical direction of the drawing by insulating banks (partitions) 18 that are continuously arranged with a fence-like or grid-like plane pattern. In addition, each color pixel area including a plurality of pixel pixels PXr, PXg, or PXb having the same color is defined. In addition, in each pixel formation region where a plurality of color pixels PXr, PXg, or PXb included in each color pixel region is formed, a pixel electrode (for example, an anode electrode) 15 is formed and the bank 18 is disposed. Parallel to the direction, a signal line Ld is arranged in the vertical direction of the drawing (that is, in the column direction), and a selection line Ls is arranged in the horizontal direction of the drawing (that is, in the row direction) perpendicular to the signal line Ld. A supply voltage line (for example, an anode line) La is connected to the drain electrode Tr12d (see FIG. 3 described later) and is provided on the drain electrode Tr12d so as to extend in the column direction. In addition, a counter electrode (for example, a cathode electrode) 17 having a single planar electrode (solid electrode) is formed in common with respect to a plurality of display pixels PIX (each pixel electrode 15) arranged two-dimensionally on the insulating substrate 11. Has been.

  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 having one or more transistors (for example, amorphous silicon thin film transistors) on an insulating substrate 11 is used. A circuit (or pixel circuit) DC, and an organic EL element (light emitting 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 a predetermined high potential power source, for example, and is a pixel electrode (for example, an anode electrode) 15 of the organic EL element OEL provided in each display pixel PIX (color pixels PXr, PXg, PXb). A predetermined high voltage (supply voltage Vdd) for applying a light emission driving current corresponding to display data is applied to the counter electrode 17, and the counter electrode 17 is directly or indirectly connected to a predetermined low potential power source, for example, and a plurality of organic EL A predetermined low voltage (common voltage Vcom; for example, ground potential Vgnd) is applied to the element OEL.

  For example, as shown in FIG. 2, the pixel driving circuit DC has a gate terminal connected to a selection line (scanning line) Ls and a drain terminal connected to a signal line (data line) Ld arranged in the column direction of the display panel 10. Transistor (selection thin film transistor) Tr11 having a terminal connected to the contact N11, a transistor 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 (light emission driving thin film transistor) ) Tr12. Here, the transistors Tr11 and Tr12 are both n-channel thin film transistors. If the transistors Tr11 and Tr12 are p-channel type, the source terminal and the drain terminal are opposite to each other.

  In the organic EL element OEL, the anode terminal (pixel electrode 15 serving as an anode electrode) is connected to the contact N12 of the pixel driving circuit DC, and the cathode terminal (counter electrode 17 serving as a cathode electrode) is common to each display pixel PIX. Connected to voltage Vcom. In addition, a parasitic capacitance or an additional auxiliary capacitance is formed between the gate and the source of the transistor Tr12. If the transistor Tr12 is a p-channel type, a parasitic capacitance or an additional auxiliary capacitance is formed between the gate and the drain.

  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. The signal line Ld is connected to a data driver (not shown), and a gradation signal Vpix corresponding to display data is applied at a timing synchronized with the selection state of the display pixel PIX.

  In the drive control operation in the display pixel PIX having such a circuit configuration, first, a selection signal Ssel of a selection level (on level; for example, high level) is applied to a selection line Ls from a selection driver (not shown). As a result, 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 signal 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.

  Thereby, the voltage between the gate and the source of the transistor Tr12 is set, and the current value of the current flowing between the drain and the source is set according to the voltage between the gate and the source, that is, the potential of the contact N11. . That is, a light emission drive current having a current value corresponding to the voltage of the gradation signal Vpix (that is, display data) flows from the supply voltage Vdd to the common voltage Vcom (ground potential Vgnd) via the transistor Tr12 and the organic EL element OEL. The organic EL element OEL emits light at a luminance gradation according to the value. At this time, carriers are accumulated (charged) in the parasitic capacitance (or auxiliary capacitance) between the gate and source of the transistor Tr12 based on the gradation signal Vpix applied to the contact N11.

  Next, by applying a selection signal Ssel of a non-selection level (off level; for example, low level) to the selection line Ls, the transistor Tr11 of the display pixel PIX is turned off and set to a non-selection state, and the signal line Ld and the pixel The drive circuit DC is electrically disconnected. At this time, the charge accumulated in the parasitic capacitance is held, so that the voltage corresponding to the gradation signal Vpix is held at the gate terminal of the transistor Tr12.

  Therefore, 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 OEL 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, as the pixel drive circuit DC constituting the display pixel PIX, the voltage value of the gradation signal Vpix is adjusted to control the current value of the light emission drive current that flows through the organic EL element OEL. Although the circuit configuration of the voltage gradation designation method (or voltage gradation designation drive) in which the light emission operation is performed at the luminance gradation is shown, the current value to be written is adjusted according to the display data to flow to the organic EL element OEL. It may have a circuit configuration of a current gradation designation method (or current gradation designation drive) in which light emission operation is performed at a predetermined luminance gradation by controlling the current value of the light emission drive current.

(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 top emission type light emitting structure in which light emitted from the organic EL layer is emitted to the view side (sealing substrate side) without passing through an insulating substrate will be described.

  FIG. 3 is a plan layout diagram illustrating an example of display pixels applicable to the display device (display panel) according to the present embodiment. 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, the wiring layer, and the like of the pixel driving circuit DC are formed is mainly shown. 4 and 5 are schematic cross-sectional views showing the AA cross section and the BB cross section in 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 regions (organic EL elements in the color pixels PXr, PXg, PXb) set on one surface side of the insulating substrate 11. In the formation region Rpx, for example, selection lines Ls are arranged in the upper edge region of the planar layout shown in FIG. A signal line Ld is arranged 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 each other, and in the column direction (vertical direction in the drawing in the vertical direction). The supply voltage line La is arranged so as to extend in the direction). In addition, an insulating bank (partition wall) is disposed in the right edge region of the planar layout so as to extend in the column direction.

  Here, for example, as shown in FIGS. 3 to 5, the selection line Ls is provided on the lower layer side (insulating substrate 11 side) than the signal line Ld via the gate insulating film 12, and the signal line Ld is , Provided below the supply voltage line La. The selection line Ls is formed in the same process as the gate electrode by patterning the gate metal layer for forming the gate electrodes Tr11g and Tr12g of the transistors Tr11 and Tr12. The signal line Ld is formed in the same process as the source and drain electrodes by patterning 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. The

  That is, as shown in FIGS. 4 and 5, the display pixel PIX includes a plurality of transistors Tr11 and Tr12 of a pixel driving circuit DC (see FIG. 2) provided in the display pixel PIX on the insulating substrate 11 and a selection line. Various wiring layers including Ls and a signal line Ld are provided, and a pixel drive is formed on the upper layer via a protective insulating film 13 and a planarization film 14 which are sequentially formed so as to cover the transistors Tr11 and Tr12 and the wiring layer. An organic EL having a pixel electrode (for example, an anode electrode) 15 connected to a 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 including a layer (light emitting functional layer) 16 and a counter electrode (for example, a cathode electrode) 17 to which a common voltage Vcom is applied is formed.

  More specifically, the pixel driving circuit DC is formed, for example, as shown in FIG. 3, by projecting in the row direction from the selection line Ls (or the signal line Ld) in which the transistor Tr11 shown in FIG. 2 is arranged in the row direction. Are arranged so as to extend along the signal wiring layer Ldx), and the transistor Tr12 is arranged so as to extend along the supply voltage line La.

  Here, each of the transistors Tr11 and Tr12 has a well-known field effect transistor structure, and each of the gate electrodes Tr11g and Tr12g formed on the insulating substrate 11 and each of the gate electrodes Tr11g via the gate insulating film 12. The semiconductor layer SMC is formed in a region corresponding to the Tr12g, and the source electrodes Tr11s and Tr12s and the drain electrodes Tr11d and Tr12d are 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 and drain electrodes 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 on the semiconductor layer SMC where the source electrode and the drain electrode are in contact. The gate electrodes Tr11g and Tr12g of the transistors Tr11 and Tr12 are both formed by patterning the same gate metal layer. The source electrodes Tr11s and Tr12s and the drain electrodes Tr11d and Tr12d of the transistors Tr11 and Tr12 are both 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 includes a gate electrode Tr11g formed integrally with the selection line Ls as shown in FIGS. The electrode Tr11d is connected to a signal wiring layer Ldx formed integrally with the signal line Ld.

  3 to 5, the transistor Tr12 is connected to the source electrode Tr11s of the transistor Tr11 through a contact hole (not shown) provided in the gate insulating film 12, and the gate electrode Tr12g is connected to the transistor Tr11. A pixel of the organic EL element OEL is formed through a contact hole HLa (contact metal MTL) in which the drain electrode Tr12d is formed below the upper supply voltage line La and the source electrode Tr12s is formed in the protective insulating film 13 and the planarization film 14. It is connected to the electrode 15.

  As shown in FIGS. 3 and 4, the supply voltage line La (anode line) has a thick film wiring structure embedded in the wiring groove HLb formed in the protective insulating film 13 and the planarizing film 14, and the contact It is formed in the same process as the contact metal MTL buried in the hole HLa.

  Then, on the planarization film 14 in each pixel formation region Rpx, as shown in FIGS. 4 and 5, for example, an organic layer having a pixel electrode 15 serving as an anode electrode, a hole transport layer 16a, and an electron transport light emitting layer 16b. 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, when the display panel 10 (organic EL element OEL) has a top emission type light-emitting structure, the pixel electrode 15 has at least light reflection characteristics, and the counter electrode 17 has light transmittance. Specifically, the pixel electrode 15 has a laminated structure having a reflective metal layer 15a on the lower layer side and a transparent metal oxide layer 15b on the upper layer side, as will be described later in a manufacturing method (see FIGS. 6 to 8). Have.

  The counter electrode 17 is formed of a single planar electrode so as to face the pixel electrode 15 at least in each pixel formation region Rpx via the organic EL layer 16 in common. 4 and 5, the counter electrode 17 is provided so as to extend not only to each pixel formation region Rpx but also to the bank 18 that defines the pixel formation region Rpx.

  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 continuously protrude from the upper surface of the planarization film 14. Here, in the present embodiment, for example, as shown in FIG. 4, the bank 18 covers the peripheral edge of the pixel electrode 15 in the column direction between the pixel electrodes 15 formed in each pixel formation region Rpx adjacent in the row direction. The function of defining the application region of the organic compound material when forming the underlying layer (insulating layer) 18x on the lower layer and the organic EL layer 16 (the hole transport layer 16a and the electron transporting light emitting layer 16b) disposed in It has a laminated structure having an upper resin layer 18a. The underlayer 18x is for improving the adhesion between the resin layer 18a and the planarization film 14, and has an expansion coefficient between the expansion coefficient of the resin layer 18a and the expansion coefficient of the planarization film 14. It is preferable. The resin layer 18a is formed so that the width in the row direction is narrower than that of the base layer 18x so that the base layer 18x is exposed from both sides in the row direction.

  More specifically, the bank 18 is formed on the peripheral edge in the column direction of the pixel electrode 15 of the organic EL element OEL from the planarization film 14 exposed in the vicinity of the boundary region between the adjacent display pixels PIX (pixel electrodes 15). A base layer 18x having a silicon nitride film (SiN) or the like is provided so that a part thereof extends, and a resin layer 18a having a photosensitive polyimide resin material is formed on the base layer 18x in the thickness direction. It is laminated so as to protrude.

  Then, as shown in FIG. 1, by arranging the banks 18 having the above laminated structure on the display panel 10 (insulating substrate 11) so as to have a planar pattern of a fence shape or a lattice shape, A pixel formation region (a formation region of the organic EL layer 16 of the organic EL element OEL) of the plurality of display pixels PIX arranged in the vertical direction of the drawing is defined. An organic EL layer 16 is formed on the pixel electrode 15.

That is, as shown in FIGS. 4 and 5, the counter electrode (cathode electrode) 17 of the organic EL element OEL is formed on each organic EL layer 16 across the bank 18, and is common to all the display pixels PIX. Therefore, as compared with the case where a voltage wiring layer to which a common voltage is applied is provided for each display pixel PIX, the manufacturing process can be greatly simplified and the wiring resistance can be reduced. Can do.
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. 4 and 5, an insulating property is provided via a transparent sealing resin layer 19. A sealing substrate 20 having 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 and Tr12 provided in a lower layer of the display panel 10 (a layer on the insulating substrate 11 side of the organic EL element OEL), a selection line Ls and a signal In the pixel driving circuit DC having wiring layers such as the line Ld and the supply voltage line (anode line) La, a predetermined current value is set based on the gradation signal Vpix corresponding to the display data supplied via the signal line Ld. A light emission driving current that flows between the drain and source of the transistor Tr12 is supplied from the transistor Tr12 (drain electrode Tr12d) to the pixel electrode 15 of the organic EL element OEL via the contact hole HLa (contact metal MTL). , Organic E of each display pixel PIX (each color pixel PXr, PXg, PXb) Element OEL emits light operation at 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 15 has light reflection characteristics and the counter electrode 17 has light transmittance (that is, 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 directly or via a counter electrode 17 having light transparency, or a pixel electrode having light reflection characteristics. The light is reflected by 15 and is emitted to one side of the insulating substrate 11 (display panel) (upward in FIGS. 4 and 5).

(Manufacturing method of display device)
Next, a method for manufacturing the above-described display device (display panel) will be described.
6 to 8 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 of the AA cross section shown in FIG. 4 will be described. FIG. 9 is a chemical symbol for explaining the modification of the bank surface formed in the display device (display panel) according to the present embodiment. FIG. 10 shows the display device (display panel) according to the present embodiment. ) Is a chemical symbol indicating the molecular structure of the bank surface formed.

  In the manufacturing method of the display device (display panel) described above, first, as shown in FIG. 6A, display pixels PIX (each color) set on one surface side (the upper surface side in the drawing) of the insulating substrate 11 such as a glass substrate. For each pixel PXr, PXg, PXb) formation region (pixel formation region) Rpx, the above-described pixel drive circuit (see FIGS. 2 and 3) DC transistors Tr11, Tr12, selection line Ls and signal line Ld (signal wiring layer). A wiring layer such as Ldx is formed (see FIGS. 4 and 5). Specifically, gate electrodes Tr11g, Tr12g and selection lines Ls (see FIG. 5) formed integrally with the gate electrode Tr11g on the insulating substrate 11 at the same time by patterning the same gate metal layer. After that, a gate insulating film 12 is formed over the entire area of the insulating substrate 11.

  Next, a semiconductor layer SMC having, for example, amorphous silicon or polysilicon is formed in a region corresponding to each gate electrode Tr11g, Tr12g on the gate insulating film 12, and impurities for ohmic connection are formed at both ends of the semiconductor layer SMC. Source electrodes Tr11s and Tr12s and drain electrodes Tr11d and Tr12d are formed through the layer OHM. At this time, a signal line Ld and a signal wiring layer Ldx (see FIGS. 4 and 5) connected to the drain electrode Tr11d are simultaneously formed by patterning the same source and drain metal layers. At this time, a contact hole (not shown) is provided in the gate insulating film 12 on the gate electrode Tr12g, and the source electrode Tr11s and the gate electrode Tr12g are connected to each other by forming the source electrode Tr11s over the contact hole. Is done.

  Note that the source electrodes Tr11s and Tr12s and the drain electrodes Tr11d and Tr12d, the selection line Ls, and the signal line Ld (including the signal wiring layer Ldx) of the transistors Tr11 and Tr12 described above reduce wiring resistance and migration. For the purpose, for example, it may have a laminated wiring structure having an aluminum alloy layer and a transition metal layer.

  Next, as shown in FIG. 6B, protection having silicon nitride (SiN) or the like so as to cover the whole area of one surface side of the insulating substrate 11 including the transistors Tr11 and Tr12, the selection line Ls, and the signal line Ld. After sequentially forming an insulating film (passivation film) 13 and a planarizing film 14 including an organic material, the planarizing film 14 and the protective insulating film 13 are etched to expose the upper surface of the source electrode Tr12s of the transistor Tr12. A wiring trench HLb corresponding to the wiring pattern of the supply voltage line La extending in the column direction is formed while exposing the hole HLa and the upper surface of the drain electrode Tr12d of the transistor Tr12.

  Next, as shown in FIG. 6C, a contact metal MTL having a metal material is embedded in the contact hole HLa by an electroless plating method or the like, and a supply voltage line La having a thick film wiring structure is embedded in the wiring groove HLb. After the formation, as shown in FIG. 6D, 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). .

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

  As described above, when patterning the upper metal oxide film, the lower reflective metal layer 15a is not exposed so as not to cause a battery reaction between the metal oxide film and the reflective metal layer 15a. In addition, it is possible to prevent the reflective metal layer 15a on the lower layer side from being over-etched or being damaged by etching.

  Next, a chemical vapor deposition method (CVD method) or the like is used to cover the entire area of one surface side of the insulating substrate 11 including the pixel electrode 15 having the reflective metal layer 15a and the metal oxide layer 15b. By forming an insulating layer having an inorganic insulating material such as a film or a silicon nitride film and then patterning, as shown in FIGS. 4, 5, and 7A, the display pixels PIX adjacent in the row direction are formed. In a region between the formed pixel electrodes 15 (that is, a boundary region with an adjacent display pixel PIX), a base layer (insulating layer) 18x serving as a lower layer of a bank 18 described later is formed along the column direction. The underlying layer 18x partially overlaps the peripheral edge of the pixel electrode 15 in the column direction.

  Next, as shown in FIG. 7B, a resin layer 18a having a photosensitive polyimide resin material is formed on the base layer 18x. Specifically, the photosensitive polyimide film formed so as to cover the entire area of the one surface side of the insulating substrate 11 including the base layer 18x is exposed and developed, and a predetermined pattern is formed on the base layer 18x. It is formed by having it remain. Here, as the resin material, for example, a polyimide coating material “Photo Nice PW-1030” manufactured by Toray Industries, Inc., a polyimide material “Kapton (registered trademark)” manufactured by DuPont, etc. can be applied satisfactorily. The resin layer 18a is formed to have a thickness of about 1 to 5 μm. Since the resin layer 18a is arranged in the center of the base layer 18x in the row direction (left-right direction in FIG. 7B), the width is narrower than the width of the base layer 18x, The upper surface is exposed from both end sides of the resin layer 18a.

  As a result, the pixel formation region (the formation region of the organic EL layer 16 of the organic EL element OEL) of the plurality of display pixels PIX of the same color arranged in the column direction of the display panel 10 has the resin layer 18a and the base layer 18x. The partition wall 18 is surrounded and defined, and the upper surface of the pixel electrode 15 (metal oxide layer 15b) is exposed in the region.

Next, the insulating substrate 11 is washed with pure water, and then subjected to oxygen plasma treatment, whereby the surface of the pixel electrode 15 exposed in each pixel formation region Rpx defined by the bank 18 is lyophilicized. The surface modification of the resin layer 18a forming the upper layer is simultaneously performed. Here, the oxygen plasma treatment is specifically performed by using, for example, a barrel type asher (model) DES-106-254AEH manufactured by Plasma System Co., Ltd., with a degree of vacuum of 0.6 Torr, a high frequency (RF) output of 250 W, oxygen (O ₂ ) A gas flow rate of 60 sccm, a chamber temperature of 80 ° C., and a processing time of 10 min are set.

  As described above, when the oxygen plasma treatment is performed on the pixel electrode 15 (metal oxide layer 15b) under the above-described treatment conditions, the pixel electrode 15 (metal oxide layer 15b) exhibits lyophilicity with respect to a polymer-based organic compound-containing liquid described later. When the oxygen plasma treatment is performed on the resin layer 18a containing photosensitive polyimide, the imide ring of the polyimide having a molecular structure as shown in FIG. A carboxyl group MS1 and an amide bond MS2 as shown in FIG. 9B are formed and separated by the moisture in the reaction atmosphere derived from the moisture adsorbed on the surface or taken into the interior.

Next, a lyophobic treatment is performed on the surface of the bank 18 (resin layer 18a) using the fluorinated alkylamine shown in FIG. Specifically, the liquid repellent treatment of the bank 18 is performed by inserting the insulating substrate 11 into a treatment bath of a liquid repellent treatment solution having a fluoroalkylamine aqueous solution containing hydrochloric acid (or chlorine). The temperature of the liquid repellent treatment solution in this treatment step is set to about 20 to 60 ° C., and the immersion time is set to about 1 to 30 minutes. Thereafter, the insulating substrate 11 is taken out of the liquid repellent treatment solution, washed with pure water, and dried by blowing nitrogen gas (N ₂ ).

In the fluoroalkylamine, one of the hydrogen atoms of the amino group (—NH ₂ ) is substituted with a chlorine group of hydrochloric acid in an aqueous solution, and this chlorine group and the oxygen plasma treatment described above generate a polyimide on the surface of the resin layer 18a. Condensation occurs with the hydrogen group of the carboxyl group (see FIG. 9B), and as shown in FIG. 10B, the surface of the resin layer 18a is substituted with a functional group containing a fluorine atom that exhibits liquid repellency. Therefore, the surface of the bank 18 exhibits strong liquid repellency. 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.

  Here, since the fluorinated alkylamine (fluorine compound) used as the liquid repellent treatment solution does not react with the oxide film or the nitride film, the metal oxide (metal oxide layer 15b) on the surface of the pixel electrode 15 and the base layer 18x are formed. Fluoroalkylamine is not bonded to the surface of the inorganic insulating film to be formed, and maintains the lyophilic property imparted by the above-described oxygen plasma treatment. The fluorinated alkylamine does not have to have a linear molecular structure as described above, and is not particularly limited as long as the number of fluorine groups can exhibit sufficient liquid repellency.

  Thereby, the fluorinated alkylamine is bonded to the surface of the resin layer 18a that forms the upper layer of the bank 18 having the resin material among the components formed on the one surface side of the insulating substrate 11, and the liquid repellent treatment is performed. Fluoroalkylamine does not bind to the surface of the pixel electrode 15 (metal oxide layer 15b) exposed in each pixel formation region Rpx defined by the bank 18 and the surface of the base layer 18x forming the lower layer of the bank 18, A state where liquid repellency treatment is not performed (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.

  In addition, the bank 18 that defines the pixel formation region Rpx of each display pixel PIX (organic EL element OEL) is isolated from the pixel formation region Rpx of the adjacent display pixel PIX (organic EL element OEL) of another color. When forming a light emitting layer (electron transporting light emitting layer 16b) to be an organic EL layer 16 to be described later, even when a solution or dispersion liquid (liquid material) of the light emitting material is applied, the adjacent display pixel PIX. The light emitting material is not mixed between (color pixels PXr, PXg, PXb), and color mixing between adjacent color pixels can be prevented.

  Next, as shown in FIG. 7C, an ink jet method in which a plurality of droplets separated from each other are ejected to a predetermined position with respect to the pixel formation region (formation region of the organic EL element OEL) of each color, or continuous In the same process by applying a nozzle coating method or the like that discharges the solution, the solution or dispersion of the hole transport material is applied and then dried by heating to form the hole transport layer (carrier transport layer) 16a. Subsequently, as shown in FIG. 8A, an ink jet method or a nozzle coating method is applied to apply a solution or dispersion of the electron transporting light emitting material on the hole transport layer 16a, and then heat drying. Thus, an electron transporting light emitting layer (carrier transporting layer) 16b is formed. Thereby, the organic EL layer (light emitting functional layer) 16 having the hole transport layer 16a and the electron transporting light emitting layer 16b is formed on the pixel electrode 15 in a stacked manner.

  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 coating oxythiophene PEDOT and a dispersion of polystyrene sulfonate PSS as a dopant in an aqueous solvent) on the pixel electrode 15 (metal oxide layer 15b), the insulating substrate 11 is placed. The stage is heated and dried under a temperature condition of 100 ° C. or more to remove the solvent, thereby fixing an organic polymer-based hole transport material on the pixel electrode 15 and transporting holes as a carrier transport layer. Layer 16a is formed.

  Here, the surfaces of the pixel electrode 15 and the surrounding underlying layer 18x are lyophilic with respect to the organic compound-containing liquid (PEDOT / PSS) by the above-described oxygen plasma treatment, and thus are defined by the bank 18. The organic compound-containing liquid applied to the formed pixel formation region Rpx spreads sufficiently in the region (on the pixel electrode 15). On the other hand, the surface of the bank 18 (resin layer 18a) has liquid repellency with respect to the organic compound-containing liquid (PEDOT / PSS) by the liquid repellency treatment using the fluorinated alkylamine aqueous solution described above. A phenomenon in which the applied organic compound-containing liquid rushes up due to a capillary phenomenon at the side wall portion of the bank 18 is suppressed, and leakage or overcoming of the organic compound-containing liquid into an adjacent pixel formation region can be prevented.

  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 tetralin. After applying a solution dissolved in an organic solvent such as tetramethylbenzene, mesitylene, xylene or water on the hole transport layer 16a, the stage and / or atmosphere on the stage is heated and dried in a nitrogen atmosphere. By removing the solvent, the organic polymer electron transporting light emitting material is fixed on the hole transporting layer 16a to form the electron transporting light emitting layer 16b which is a carrier transporting layer and also a light emitting layer.

  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 spreads sufficiently in the region (hole transport layer 16a). On the other hand, since the surface of the bank 18 (resin 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 into and over the adjacent pixel formation region. Can do.

  Thereafter, as shown in FIG. 8B, a light-transmitting 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, for example, by forming a thin film having a metal material such as barium, magnesium, lithium, or an alloy thereof serving as an electron injection layer by an evaporation method, a sputtering method, or the like, and an ITO or the like on the upper layer by a sputtering method or the like. A transparent film structure in which a transparent electrode layer or a thin film of aluminum or the like is laminated and formed in the thickness direction can be applied.

  Further, the counter electrode 17 is not only a region facing the pixel electrode 15 but also a single conductive layer (not shown) extending to the bank 18 that defines each pixel formation region Rpx (formation region of the organic EL element OEL). Flat electrode; solid electrode). This simplifies the manufacturing process as compared with the case where the power supply wiring layer for applying the common voltage Vcom to the counter electrode 17 serving as the cathode electrode is provided for each display pixel PIX on the insulating substrate 11. Wiring resistance can be reduced.

  Next, after forming the counter electrode 17, a sealing layer 19 having a silicon oxide film, a silicon nitride film, or the like as a protective insulating film (passivation film) is formed on one surface side of the insulating substrate 11 using a CVD method or the like. Furthermore, the cross-sectional structure as shown in FIGS. 4 and 5 is obtained by bonding a countersunk sealing lid or a flat sealing substrate 20 using UV curing or thermosetting adhesive. The display panel 10 is completed.

Next, specific effects of the display device and the manufacturing method thereof according to the above-described embodiment will be specifically described.
First, the liquid repellency and lyophilicity of the display panel surface (substrate surface) when the manufacturing method according to this embodiment is applied will be described.

  Table 1 shows that an oxygen plasma treatment is performed on the ITO film forming the pixel electrode 15 (metal oxide layer 15b) and the polyimide film forming the bank 18 (resin layer 18a) in the display panel according to the above-described embodiment. FIG. 5 shows the experimental results of measuring the pure water contact angle and the mesitylene contact angle when the lyophobic treatment is performed using the fluorinated alkylamine aqueous solution after the oxygen plasma treatment in the manufacturing method according to the present embodiment. Here, the treatment conditions in the oxygen plasma treatment and the treatment conditions in the lyophobic treatment using the fluorinated alkylamine aqueous solution were set to be the same as those shown in the manufacturing method described above.

  As shown in Table 1, when the oxygen plasma treatment was performed on the substrate on which the ITO film and the polyimide film were formed, the pure water contact angle on the surface of the ITO film was 5 °, which is a good parent to pure water. In addition to exhibiting liquid properties, the pure water contact angle on the surface of the polyimide film was 10 ° and the mesitylene contact angle was 14 °, indicating a relatively high lyophilic result.

  On the other hand, as shown in the above-described embodiment, when the liquid repellency treatment is performed using the fluorinated alkylamine aqueous solution after the oxygen plasma treatment, the pure water contact angle on the surface of the ITO film is 15 °, In addition, the contact angle of pure water on the surface of the polyimide film is 73 ° and the contact angle of mesitylene is 54 °. Compared to the surface of the ITO film, only oxygen plasma treatment can be performed. Compared with the case where it gave, the result which shows comparatively high liquid repellency was obtained.

  As a result, only the surface of the bank 18 (resin layer 18a) having polyimide formed on the substrate is selectively subjected to the liquid repellent treatment, and the region (pixel electrode surface) exhibiting lyophilicity on the single substrate is repelled. It has been found that a good hydrophilic / hydrophobic pattern can be formed by coexisting with a region exhibiting liquidity (bank surface).

  Next, the uniformity of the film thickness of the organic EL layer (hole transport layer and electron transporting light emitting layer) when the manufacturing method according to the present embodiment is applied will be described. Here, a simple model (see FIG. 11) is produced in the panel structure (see FIG. 5) of the cross-sectional structure of the display panel shown in FIG. 4 (cross section AA in the planar layout shown in FIG. 3). The surface height distribution (film thickness profile) when an EL film (hole transport layer) was formed was measured.

  FIG. 11 is a cross-sectional dimension diagram showing specific numerical values in the display panel (simple model) used for measuring the surface height distribution (film thickness profile) in the display device according to the present embodiment. These are actual measurement data showing the distribution of surface height (film thickness profile) in the display panel having the cross-sectional dimension shown in FIG. Here, the measurement was performed using a contact-type step meter (Surfcoder ET4000 manufactured by Kosaka Laboratory Ltd.). FIG. 11B shows a cross-sectional dimension, and FIG. 11A shows an example of a planar layout corresponding to the cross-sectional dimension. In FIG. 11A, for the sake of simplicity, the region where the metal oxide layer (ITO) serving as the pixel electrode is exposed is hatched for convenience. FIG. 13 is a conceptual diagram showing a state change of the film surface in the step of forming the organic EL layer (hole transport layer) according to this embodiment.

  As shown in FIGS. 11A and 11B, the specific cross-sectional structure in the simple model of the display panel has a predetermined plane pattern on the glass substrate 101 (corresponding to the insulating substrate 11 described above). An ITO film 102 (corresponding to the metal oxide layer 15b forming the pixel electrode 15 described above) is formed, and a part of the ITO film 102 extends from the region where the glass substrate 101 around the ITO film 102 is exposed onto the ITO film 102. The silicon nitride film 103 (corresponding to the above-described underlayer 18x) is formed so that the upper surface of the ITO film 102 is exposed through a rectangular opening having an opening width W1 of 50 to 60 μm. .

  On the silicon nitride film 103, the bank-like polyimide film 104 (the upper layer of the bank 18 described above) is formed so that the pitch P1 in the cross-sectional direction (left and right direction in the drawing) is 150 to 180 μm and the separation distance W2 is 80 to 100 μm. (Corresponding to a resin layer 18a for forming) is disposed in parallel, and a region surrounded by the polyimide film 104 is defined as a pixel formation region. Here, the silicon nitride film 103 is exposed between the end of the opening of the silicon nitride film 103 and the end of the polyimide film 104 with a width W3 of 5 to 30 μm.

  In a model of a display panel having such a cross-sectional structure, a region in which PEDOT / PSS is surrounded by a polyimide film 104 as an organic compound-containing liquid for forming a hole transport layer in a state where only oxygen plasma treatment is performed ( In the case where the hole transport layer is formed by applying to the pixel formation region) and, as shown in the above-described embodiment, after the oxidation plasma treatment, the fluorinated alkylamine aqueous solution is used to perform the liquid repellency treatment. When the hole transport layer was formed by applying PEDOT / PSS, the distribution of the surface height of the hole transport layer was measured. Here, the treatment conditions in the oxygen plasma treatment and the treatment conditions in the lyophobic treatment using the fluorinated alkylamine aqueous solution were set to be the same as those shown in the manufacturing method described above.

  As a result, as shown in FIG. 12, as shown in the present embodiment, after the oxidation plasma treatment, when the lyophobic treatment is performed using the fluorinated alkylamine aqueous solution, only the oxygen plasma treatment is performed. In comparison with the above, the hole transport layer is thicker in the entire area inside the opening provided in the silicon nitride film 103 (that is, on the ITO film 102), and the side surface of the polyimide film 104 forming the bank As a result, the film thickness on the upper surface of the silicon nitride film 104 was reduced (showing a state closer to the shape of the substrate surface).

  Table 2 shows the case where only the oxygen plasma treatment is performed in the surface height distribution (thickness profile of the hole transport layer) of the display panel shown in FIG. 12, and the oxygen plasma treatment in the manufacturing method according to the present embodiment. It is the experimental result which measured the dispersion | variation in the film thickness inside the opening part (namely, on the ITO film | membrane 102) provided in the silicon nitride film 103 at the time of performing lyophobic treatment using the fluorinated alkylamine aqueous solution later.

Here, the maximum value and the minimum value of the film thickness are measured for the hole transport layer formed inside the opening portion (on the ITO film 102) having the opening width W1 by using a contact step meter, and the average is obtained. And the variation was calculated. In this case, because of the structure of the contact-type step meter, the film thickness at the end of the opening cannot be measured, so the variation in the range of substantially 47.6 μm was compared with the opening width W1. Here, the following calculation formula (1) is used as the definition of variation.
Variation (%) = (maximum film thickness−minimum film thickness) / (maximum film thickness + minimum film thickness) × 100 (1)

  As shown in Table 2, when oxygen plasma treatment was applied to the substrate (ITO film), the maximum thickness of the hole transport layer was 55.2 nm, the minimum thickness was 21.6 nm, and the average over the entire opening. The film thickness was 30.2 nm, and the variation was calculated to be 43.8% using the above calculation formula (1), and a result having a relatively large variation was obtained.

  On the other hand, as shown in the above-described embodiment, when the lyophobic treatment is performed using the fluorinated alkylamine aqueous solution after the oxygen plasma treatment, the maximum film thickness of the hole transport layer is 66.2 nm and the minimum film thickness is 40. .2 nm, the average film thickness over the entire opening is 48.1 nm, and the variation is calculated to be 24.7% using the above calculation formula (1), compared with the case where only the oxygen plasma treatment is performed. As a result, the variation was greatly suppressed.

  As a result, the surface of the pixel electrode (ITO film) exposed to the pixel formation region by the manufacturing method according to the present embodiment is made lyophilic by oxygen plasma treatment, and the surface of the bank (polyimide film) that defines the pixel formation region is alkyl fluoride. By making the liquid repellent using an aqueous amine solution, the organic compound-containing liquid (PEDOT / PSS) is prevented from adhering to the side of the bank, while being well adapted to the surface of the pixel electrode, and uniform organic with little film thickness variation. It has been found that an EL layer (hole transport layer) can be formed.

  That is, in the step of forming the organic EL layer (hole transport layer), as shown in FIG. 13A, the PEDOT / PSS applied to the pixel formation region defined by the polyimide film 104 is changed to the PEDOT / PSS. On the other hand, it spreads on the surface of the ITO film 102 and the silicon nitride film 103 having lyophilic properties, while being repelled on the surface of the polyimide film 104 having liquid repellency, and therefore has a dome-shaped cross section in the region between the polyimide films 104. Will stay.

  When the heat drying process is performed in such a state, as shown in FIG. 13B, the PEDOT / PSS is sufficiently familiar and spreads on the surface of the ITO film 102 and the silicon nitride film 103, so that the PEDOT / PSS solution Drying proceeds in a state where the surface is pulled to the marginal region, the aggregation of the organic compound in the central region of the opening is suppressed, and the film thickness of the organic EL layer 16 (hole transport layer 16a) is substantially all over the opening. Is considered to be uniform.

  As described above, according to the display device and the manufacturing method thereof according to the present embodiment, as a bank for demarcating each display pixel (pixel formation region), a base layer having a silicon nitride film or the like, and a polyimide-based layer Applying a laminated structure including a resin layer having a photosensitive resin, the surface of the pixel electrode (metal oxide film having ITO or the like) exposed to each pixel formation region by oxygen plasma treatment and the surface of the underlayer are made lyophilic, Then, by repelling the resin layer surface using a fluoroalkylamine aqueous solution, the organic compound-containing liquid (PEDOT / PSS etc.) that becomes the organic EL layer (hole transport layer) is applied to the side surface of the resin layer (bank). The organic compound can be fixed by heating and drying in a state in which the surface of the pixel electrode is well-adapted while suppressing adhesion, so that light emitting materials of different colors can be used in adjacent pixel formation regions. Mixing phenomenon can be prevented, mixing of luminescent colors between display pixels (mixed color) can be suppressed, and uniform organic EL layer (light emitting functional layer) with little variation in film thickness over almost the entire area of the pixel electrode. Can be formed.

  Therefore, according to the present embodiment, a desired display image quality can be obtained by suppressing a deviation from the design value of the light emission start voltage during the light emission operation and the wavelength (chromaticity) of the light emitted from the organic EL layer. In addition, it is possible to suppress the deterioration of the organic EL element and realize a display panel having excellent reliability and life.

  In the verification of the effect described above, the case where the hole transport layer 16a is formed by applying PEDOT / PSS as the organic compound-containing liquid on the ITO film (metal oxide layer) serving as the pixel electrode has been described. The present invention is not limited to this, and it has been confirmed that even when the electron-transporting light-emitting layer 16b is formed on the hole-transporting layer 16a, the same effects can be obtained.

In the above-described embodiment, the case where the oxygen plasma treatment is applied as the treatment for lyophilicizing the surface of the metal oxide layer (ITO or the like) forming the pixel electrode has been described. However, the present invention is not limited to this. Instead, it has been confirmed that even when the UV ozone treatment is applied, the same operational effects as when the oxygen plasma treatment is applied are obtained.
Furthermore, in the above-described embodiment, the display panel having the top emission type light emitting structure has been described. However, the present invention is not limited to this, and the display panel may have a bottom emission type light emitting structure. .

The case where the present invention is applied to a display panel having a bottom emission type light emitting structure will be described below.
FIG. 14 is a schematic sectional view showing another embodiment of the display device (display panel) according to the present invention. Here, about the structure equivalent to embodiment mentioned above, the same or equivalent code | symbol is attached | subjected and the description is simplified.

  A panel structure of a display panel having a bottom emission type light emitting structure is, for example, as shown in FIG. 14A, a pixel electrode 15 and a pixel electrode 15 are formed on a gate insulating film 12 formed on an insulating substrate 11. A transistor Tr12 having one end of the source electrode Tr12s electrically connected thereto and a transistor Tr11 (not shown) are formed. The transistor Tr12 covers the transistors Tr12 and Tr11 and has an opening that exposes the upper surface of the pixel electrode 15. A base layer 18x as an insulating film is formed. Further, a resin layer 18a that protrudes continuously is formed on the base layer 18x with a fence-like or grid-like plane pattern, and the pixel electrode 15 in each pixel formation region Rpx is interposed via the organic EL layer 16. The counter electrode 17 having a single planar electrode is formed so as to face each other in common and further extend onto the resin layer 18a.

  Here, the pixel electrode 15 is formed of an electrode material having optical transparency such as ITO, and the counter electrode 17 is calcium, barium, magnesium having a thickness of about 1 to 30 nm on the surface in contact with the organic EL layer 16. Further, it is made of a metal material having a low work function such as lithium or an electron injecting film of an alloy thereof and a metal material having light reflection characteristics such as aluminum having a thickness of about 50 to 1000 nm. Thereby, the light emitted from the organic EL layer is reflected directly through the pixel electrode 15 having light transmissivity or by the counter electrode having light reflection characteristics, and the back side of the insulating substrate (display panel) 11 (That is, the light is emitted downward in FIG. 14A).

  Also in the display panel having such a panel structure, the pixel electrode 15 and the transistors Tr11 and Tr12 are formed on the insulating substrate 11 as shown in FIG. In the state where the base layer 18x and the resin layer 18a are formed, oxygen plasma treatment or UV ozone treatment is performed to make at least the surface of the pixel electrode (ITO film) lyophilic, and then using the fluorinated alkylamine aqueous solution, The surface of the resin layer 18a forming the upper layer is made liquid repellent.

  Thereafter, an organic compound-containing liquid containing a hole transporting material or an electron transporting light emitting material is applied, and fixed by heat drying, whereby the hole transporting layer 16a and the electron transporting light emitting layer 16b are sequentially formed. The At this time, as shown in the above-described embodiment, since a good hydrophilic / hydrophobic pattern is formed on the insulating substrate 11, the pixel electrode is suppressed while preventing the organic compound-containing liquid from adhering to the surface of the resin layer 18a. 15 can be well adapted to the surface and spread, can suppress the mixing (color mixing) of the luminescent color between adjacent display pixels, and can be a uniform organic with little variation in film thickness over almost the entire area of the pixel electrode. An EL layer (light emitting functional layer) can be formed.

In each of the above-described embodiments, 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, a hole The light-emitting layer may be only a transport and electron-transporting layer, may be a hole-transporting light-emitting layer and an electron-transporting layer, or a carrier transporting layer may be appropriately interposed between them, or may be a combination of other carrier transporting layers Good.
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.

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 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 a chemical symbol for demonstrating modification | reformation of the bank surface formed in the display apparatus (display panel) which concerns on this embodiment. It is a chemical symbol which shows the molecular structure of the bank surface formed in the display apparatus (display panel) which concerns on this embodiment. It is a cross-sectional dimension figure which shows the specific numerical value in the display panel (simple model) used in order to measure distribution of surface height (film thickness profile) in the display apparatus which concerns on this embodiment. It is actual measurement data which shows surface height distribution (film thickness profile) in a simple model. It is a conceptual diagram which shows the state change of the film | membrane surface in the formation process of the organic electroluminescent layer (hole transport layer) which concerns on this embodiment. It is a schematic sectional drawing which shows other embodiment of the display apparatus (display panel) which concerns on this invention.

Explanation of symbols

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

Claims (6)

In a method for manufacturing a display device including a plurality of display pixels including a light emitting element having a carrier transport layer,
Forming a partition wall with a polyimide-based resin material between the formation regions of the plurality of display pixels each provided with a pixel electrode on a substrate;
Oxygen plasma treatment or UV ozone treatment is performed to make the surface of the pixel electrode lyophilic with respect to an organic solution containing a carrier transporting material, and at the same time, the imide ring on the surface of the partition wall is opened to generate a carboxyl group And modifying the process,
Immersing the partition in a solution of fluorinated alkylamine , binding the fluorinated alkylamine to a carboxyl group on the surface of the partition, and making the organic solution containing the carrier transporting material liquid repellent;
A method for manufacturing a display device, comprising: The solution of the fluorinated alkyl amines, method of manufacturing a display device according to claim 1, characterized in that the aqueous solution of the fluorinated alkyl amines containing hydrochloric acid. The said partition is formed on the insulating layer which consists of a silicon nitride film or a silicon oxide film formed on the said board | substrate between the formation area of the said display pixel, The said Claim 1 or 2 characterized by the above-mentioned. Method of manufacturing the display device. The formation region of the display pixels, a method of manufacturing a display device according to any one of claims 1 to 3, characterized in that it is defined by the partition wall. Coating the organic solution containing the carrier transporting material on the lyophilic pixel electrode and drying to form the carrier transport layer;
A step of forming a single counter electrode that is commonly opposed to the pixel electrodes of the plurality of display pixels through the carrier transport layer and that extends on the liquid-repellent partition walls. When,
Method of manufacturing a display device according to any one of claims 1 to 4, further comprising a. Display device, characterized in that it is manufactured by the manufacturing method of a display device according to any one of claims 1 to 5.