OLED display device and method for manufacturing OLED display device

Abstract

The present invention relates to an OLED display device and a method for manufacturing the OLED display device. The OLED display device comprises: a substrate; a sub-pixel line on the substrate; and a coating material separation layer on the substrate. Each sub-pixel line comprises sub-pixels of the same color arranged along a first axis. The coating material separation layer has a coating separation opening. Each coating separation opening contains sub-pixels of the same color that are continuous in a sub-pixel row. In each coating separation opening, the organic light-emitting films of the sub-pixels of the same color are connected by an organic light-emitting film made of the same material as the organic light-emitting film of the sub-pixel. When observed along a second axis perpendicular to the first axis, the position of the dam between the coating separation openings in each sub-pixel line is different from the position of the dam between the coating separation openings in adjacent sub-pixel lines.

Description

Technical Field

[0001] The invention relates to an organic light-emitting diode (OLED) display device and a method for manufacturing the OLED display device. Background Art

[0002] Organic light-emitting diode (OLED) elements are current-driven self-luminous elements, so they do not require backlight. In addition, OLED elements have the advantages of achieving low power consumption, wide viewing angles, and high contrast, and are highly anticipated in the development of flat panel display devices.

[0003] The display area of ​​a color display device is generally composed of sub-pixels of three primary colors, red (R), green (G), and blue (B). The sub-pixels are arranged on a substrate of a display panel. Various arrangements of sub-pixels (pixel arrangements) have been proposed. For example, an RGB stripe arrangement and a delta-nabla arrangement (also referred to as a delta arrangement) are known.

[0004] Known methods for manufacturing OLED elements include a vapor deposition method in which an organic EL material is vapor-deposited on a substrate and a printing method in which an organic EL material dissolved in an organic solvent is applied to a substrate by printing. Generally, the organic electroluminescent (EL) material used in the vapor deposition method is a low molecular weight material, and the organic EL material used in the printing method is a high molecular weight material.

[0005] The vapor deposition method requires a metal mask to vapor-deposit different light-emitting materials on a substrate, and the utilization rate of the materials is low. In contrast, the printing method does not require a mask; the utilization rate of organic EL materials is high, allowing large-area printing. However, the trend toward higher-resolution OLED panels requires a smaller pitch between sub-pixels; technology to reduce the risk of color mixing of inks is important.

[0006] One of the printing methods uses inkjet technology. Inkjet technology ejects ink droplets from a nozzle to apply the ink droplets to a substrate. After forming a thin film transistor (TFT) array, an insulating coating material separation layer with multiple openings (bank openings) is formed in an active matrix OLED display device using inkjet technology. In each bank opening, one or more electrodes for one or more sub-pixels of the same color are included. The inkjet method ejects ink into the bank opening. Therefore, the coating material separation layer prevents the mixing of ink colors. Summary of the invention

[0007] The brightness of a sub-pixel depends on the thickness of the organic light-emitting film remaining after the ink dries. In forming an OLED element by printing, it is important to reduce the unevenness of the brightness to be perceived.

[0008] One aspect of the present invention is an OLED display device, comprising: a substrate; a plurality of sub-pixel lines on the substrate, each of the plurality of sub-pixel lines including a plurality of sub-pixels of the same color arranged along a first axis; and a coating material separation layer on the substrate, the coating material separation layer having a plurality of coating separation openings. Each of the plurality of coating separation openings contains a plurality of sub-pixels of the same color that are continuous in one sub-pixel line. Within each coating separation opening, the organic light-emitting films of the plurality of sub-pixels of the same color are connected by an organic light-emitting film made of the same material as the organic light-emitting films of the plurality of sub-pixels. When observed along a second axis perpendicular to the first axis, the position of the dam between the coating separation openings in each of the plurality of sub-pixel lines is different from the position of the dam between the coating separation openings in adjacent sub-pixel lines.

[0009] Another aspect of the present invention is a method for manufacturing an OLED display device, the method comprising: forming a plurality of sub-pixel electrode lines on a substrate, each of the plurality of sub-pixel electrode lines consisting of a plurality of sub-pixel electrodes arranged on a line along a first axis; forming a coating material separation layer having a plurality of coating separation openings, each of the plurality of coating separation openings being formed to contain a plurality of sub-pixel electrodes; and ejecting an organic EL ink into each of the plurality of coating separation openings. During the formation of the coating material separation layer, when viewed along a second axis perpendicular to the first axis, the position of the dam between the coating separation openings in each of the plurality of sub-pixel electrode lines is different from the position of the dam between the coating separation openings in adjacent sub-pixel electrode lines.

[0010] An aspect of the present invention is to reduce non-uniformity in brightness to be perceived on an OLED display device.

[0011] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematically shows an example of the structure of an OLED display device;

[0013] Figure 2A An example of the structure of a pixel circuit is shown;

[0014] Figure 2B Another structural example of a pixel circuit is shown;

[0015] Figure 3 Schematically shows a cross-sectional structure of a portion including a driving TFT of an OLED display device;

[0016] Figure 4 Schematically showing sub-pixels in a △-▽ arrangement;

[0017] Figure 5 An example of a pattern of a coating separation opening of a coating material separation layer is shown;

[0018] Figure 6 is a diagram showing uneven brightness of sub-pixels in a coating separation opening and a structure in which uneven brightness is hardly perceived; and

[0019] Figure 7 Another example of the pattern of the coating separation openings of the coating material separation layer is shown. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention are described with reference to the accompanying drawings. It should be noted that the embodiments are only examples of implementing the present invention and do not limit the technical scope of the present invention. In order to clearly understand the description, the size or shape of some elements in the accompanying drawings are exaggerated.

[0021] The organic light emitting diode (OLED) display device in the present invention includes a coating material separation layer having a plurality of openings. In each opening, a plurality of OLED elements (sub-pixels) of the same color are formed. An organic EL material of one color is coated in each opening. The boundaries between the openings of the coating material separation layer are arranged to be staggered. This arrangement reduces the non-uniformity of brightness to be perceived on the OLED display device.

[0022] Overall structure

[0023] Figure 1 The schematic diagram shows an example of the structure of an OLED display device 10. The OLED display device 10 includes a thin film transistor (TFT) substrate 100 on which an OLED element (organic light emitting element) is formed, and a structural packaging unit 200 for packaging the OLED element.

[0024] A scan driver 131, a protection circuit 133, a driver IC 134, and a demultiplexer 136 are provided at the periphery of the cathode electrode forming region 114 outside the display region 125 of the TFT substrate 100. The driver IC 134 is connected to an external device through a flexible printed circuit (FPC) 135. The scan driver 131 drives the scan lines on the TFT substrate 100. The protection circuit 133 protects the elements from electrostatic discharge. The driver IC 134 is mounted with, for example, an anisotropic conductive film (ACF).

[0025] The driver IC 134 supplies power and a timing signal (control signal) to the scan driver 131, and also supplies power and a data signal to the demultiplexer 136. The demultiplexer 136 sequentially outputs the output of one pin of the driver IC 134 to d data lines (d is an integer greater than 1). The demultiplexer 136 changes the output data line for the data signal from the driver IC 134 d times per scan cycle to drive as many data lines as d times the output pin of the driver IC 134.

[0026] Pixel circuit

[0027] A plurality of pixel circuits are formed on the TFT substrate 100 to control current to be supplied to anode electrodes (sub-pixel electrodes) of sub-pixels. Figure 2A An example of the structure of a pixel circuit is shown. Each pixel circuit includes a driving transistor T1, a selection transistor T2, an emission transistor T3, and a storage capacitor C1. The pixel circuit controls the light emission of the OLED element E1. The transistor is a TFT.

[0028] The selection transistor T2 is a switch for selecting a sub-pixel. Figure 2A The selection transistor T2 in FIG. 1 is a p-channel TFT, and its gate terminal is connected to the scanning line 106. The source terminal of the selection transistor T2 is connected to the data line 105. The drain terminal of the selection transistor T2 is connected to the gate terminal of the driving transistor T1.

[0029] The driving transistor T1 is a transistor (driving TFT) for driving the OLED element E1. Figure 2A The driving transistor T1 in FIG. 1 is a p-channel TFT, whose gate terminal is connected to the drain terminal of the selection transistor T2. The source terminal of the driving transistor T1 is connected to the power supply line (Vdd) 108. The drain terminal of the driving transistor T1 is connected to the source terminal of the emission transistor T3. The storage capacitor C1 is provided between the gate terminal and the source terminal of the driving transistor T1.

[0030] The emission transistor T3 is a switch for controlling supply / stop of a driving current to the OLED element E1. Figure 2A The emission transistor T3 in FIG. 1 is a p-channel TFT, and its gate terminal is connected to the emission control line 107. The source terminal of the emission transistor T3 is connected to the drain terminal of the driving transistor T1. The drain terminal of the emission transistor T3 is connected to the OLED element E1.

[0031] Next, the operation of the pixel circuit is described. The scan driver 131 outputs a selection pulse to the scan line 106 to turn on the transistor T2. The data voltage supplied from the driver IC 134 via the data line 105 is stored in the storage capacitor C1. The storage capacitor C1 holds the stored voltage during one frame period. The conductivity of the driving transistor T1 changes in an analog manner according to the stored voltage, so that the driving transistor T1 supplies a forward bias current corresponding to the light emission level to the OLED element E1.

[0032] The emission transistor T3 is located on the supply path of the drive current. The driver IC 134 outputs a control signal to the emission control line 107 to control the on / off of the emission transistor T3. When the emission transistor T3 is turned on, the drive current is supplied to the OLED element E1. When the emission transistor T3 is turned off, the supply stops. By controlling the on / off of the transistor T3, the light emission period (duty cycle) within a frame cycle can be controlled.

[0033] Figure 2B Another structural example of a pixel circuit is shown. The pixel circuit includes a reset transistor T4 to replace Figure 2A The reset transistor T4 controls the electrical connection between the reference voltage supply line 110 and the anode of the OLED element E1. This control is performed according to a reset control signal supplied to the gate of the reset transistor T4 via the reset control line 109.

[0034] The reset transistor T4 can be used for various purposes. For example, the reset transistor T4 can be used to reset the anode electrode of the OLED element E1 to a sufficiently low voltage below the black signal level to prevent crosstalk caused by leakage current between the OLED elements E1.

[0035] The reset transistor T4 can also be used to measure the characteristics of the drive transistor T1. For example, the voltage-current characteristics of the drive transistor T1 can be accurately measured by measuring the current flowing from the power supply line (Vdd) 108 to the reference voltage supply line (Vref) 110 under the selected bias conditions, so that the drive transistor T1 will operate in the saturation region and the reset transistor T4 will operate in the linear region. If the difference in the voltage-current characteristics between the drive transistors T1 of each sub-pixel is compensated by generating a data signal on an external circuit, a very uniform display image can be obtained.

[0036] Meanwhile, when the driving transistor T1 is turned off and the reset transistor T4 operates in the linear region, the voltage-current characteristic of the OLED element E1 can be accurately measured by applying a voltage that causes the OLED element E1 to emit light from the reference voltage supply line 110. For example, in the case where the OLED element E1 is degraded due to long-term use, if the degradation is compensated by generating a data signal on an external circuit, the display device can have a long life.

[0037] Figure 2A and Figure 2B The circuit structure in is an example; the pixel circuit may have a different circuit structure. Figure 2A and Figure 2B The pixel circuit in includes a p-channel TFT, but the pixel circuit can also use an n-channel TFT.

[0038] Pixel structure

[0039] Next, the overall structure of a pixel circuit and a light emitting element is described. Figure 3 The cross-sectional structure of a portion including a driving TFT of an OLED display device 10 is schematically shown. The OLED display device 10 includes a TFT substrate 100 and a structural encapsulation unit 200 opposite to the TFT substrate 100. Hereinafter, the definitions of top and bottom correspond to the top and bottom of the figure.

[0040] Figure 3 1 shows a flexible OLED panel before being peeled off from a support substrate 141. The OLED display device 10 includes an OLED panel and a driver IC 134. The OLED panel includes a TFT substrate 100 and a structural packaging unit 200. During the manufacturing process, the OLED panel is bonded to a glass support substrate 141 through a peeling layer 142. After the process is completed, the support substrate 141 is physically or chemically separated from the peeling layer 142.

[0041] The OLED display device (OLED panel) 10 includes an insulating flexible substrate 143 and a structural packaging unit opposite to the flexible substrate 143. An example of the structural packaging unit is a flexible or non-flexible packaging substrate. The structural packaging unit can also be a thin film encapsulation (TFE) structure. Figure 3 An example of a TFE structure is shown.

[0042] The flexible substrate 143 is made of polyimide, for example. A multilayer film formed by alternately stacking inorganic thin film layers 144, 146, and 148 and organic thin film layers 145 and 147 is provided between the flexible substrate 143 of the TFT array and the base film 152. The inorganic thin film layers 144, 146, and 148 are used to prevent moisture or oxygen from penetrating. Generally, the inorganic thin film layers 144, 146, and 148 are made of silicon nitride or aluminum oxide. The organic thin film layers 145 and 147 are used to prevent damage or act as buffers against bending.

[0043] The OLED display device 10 includes a lower electrode (eg, an anode electrode 162 ), an upper electrode (eg, a cathode electrode 166 ), and an organic light emitting film (organic EL device) 165 disposed between a flexible substrate 143 and a structural packaging unit.

[0044] The organic light-emitting film 165 is disposed between the cathode electrode 166 and the anode electrode 162. A typical organic light-emitting film 165 is a multilayer organic film and includes, for example, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. Layers other than the light-emitting layer are optional. A plurality of anode electrodes 162 are disposed on the same plane (for example, on the planarization film 161), and the organic light-emitting film 165 is disposed on the anode electrode 162. Figure 3 In the example of FIG. 1 , the cathode electrode 166 of one sub-pixel is part of an unseparated conductor film.

[0045] The OLED display device 10 further includes a plurality of pixel circuits, each of which includes a plurality of transistors. Each of the plurality of pixel circuits is formed between the flexible substrate 143 and the anode electrode 162 , and controls a current to be supplied to the anode electrode 162 .

[0046] Figure 3 An example of a top emission pixel structure is shown, which includes an OLED element of a top emission type. The top emission pixel structure is configured such that a cathode electrode 166 shared by multiple pixels is arranged on the light-emitting side (upper side of the figure). The cathode electrode 166 has a shape that completely covers the entire display area 125. The top emission pixel structure is characterized in that the anode electrode 162 has light reflectivity and the cathode electrode 166 has light transmittance. Therefore, a structure is achieved in which light from the organic light-emitting film 165 is transmitted toward the structural encapsulation unit.

[0047] Compared with the bottom emission pixel structure configured to extract light from the flexible substrate 143, the top emission type does not require a light transmission area in the pixel area for extracting light. Therefore, the top emission type has high flexibility when laying out the pixel circuit. For example, the light emitting unit can be arranged above the pixel circuit or wiring. The bottom emission pixel structure has a transparent anode electrode and a reflective cathode electrode so that light is transmitted to the outside via the flexible substrate 143. The features of the present invention are also applicable to the bottom emission pixel structure.

[0048] The sub-pixels of a full-color OLED display device usually display one color among red, green and blue. A red sub-pixel, a green sub-pixel and a blue sub-pixel constitute a main pixel. A pixel circuit including a plurality of transistors controls the light emission of the OLED element associated therewith. The OLED element is composed of an anode electrode, an organic light-emitting film and a cathode electrode.

[0049] A polysilicon layer is provided on the base film 152. The polysilicon layer includes a channel 155 at a position where a gate electrode 157 is to be formed later. A source region 168 and a drain region 169 are provided at both ends of each channel 155. The source region 168 and the drain region 169 are doped with high-concentration impurities for electrical connection to the wiring layer thereover.

[0050] A region doped with low-concentration impurities may be provided between the channel 155 and the source region 168 and between the channel 155 and the drain region 169. Figure 3 These regions are omitted in FIG. 1. Above the polysilicon layer, a gate electrode 157 is provided, and a gate insulating film 156 is interposed between the polysilicon layer and the gate electrode 157. An interlayer insulating film 158 is provided on the layer of the gate electrode 157.

[0051] In the display area 125, a source electrode 159 and a drain electrode 160 are provided above the interlayer insulating film 158. The source electrode 159 and the drain electrode 160 are formed of a metal having a high melting point or an alloy of such a metal. Each source electrode 159 and each drain electrode 160 are connected to a source region 168 and a drain region 169 of the polysilicon layer through contact holes 170 and 171 provided in the interlayer insulating film 158 and the gate insulating film 156.

[0052] Above the source electrode 159 and the drain electrode 160, an insulating planarizing film 161 is provided. Anode electrodes 162 are provided above the insulating planarizing film 161. Each anode electrode 162 is connected to the drain electrode 160 through a contact portion in a contact hole 172 provided in the planarizing film 161. A TFT of a pixel circuit is formed below the anode electrode 162.

[0053] Above the anode electrode 162, an insulating pixel defining layer (PDL) 163 is provided to separate the OLED elements. The pixel defining layer 163 is made of an insulating material that tends not to repel (has high wettability to) the ink (organic EL ink) including an organic EL material. For example, the pixel defining layer 163 is made of silicon nitride. The organic EL ink includes an organic EL material and a solvent. The pixel defining layer 163 has an opening pattern including a plurality of openings (PDL openings) 167. The bottom of the PDL opening 167 is the anode electrode 162, and each OLED element is formed in the PDL opening 167 of the pixel defining layer 163. The shape of the PDL opening 167 corresponds to the shape of the sub-pixel (its light-emitting area).

[0054] An insulating coating material separation layer 164 for separating organic EL ink is provided above the pixel defining layer 163. The coating material separation layer 164 is composed of an insulating material that tends to repel the organic EL ink (has low wettability to the organic EL ink). For example, the coating material separation layer 164 is made of a photosensitive resin. The coating material separation layer 164 is thicker than the pixel defining layer 163. The coating material separation layer 164 has an opening pattern including a plurality of openings (coating separation openings) 149. The insulating region between the coating separation openings 149 is called a dike. Each dike is a portion of the coating material separation layer 164. Each coating separation opening 149 is surrounded and separated by a dike.

[0055] A plurality of OLED elements (sub-pixels) of the same color are arranged in each coating separation opening 149. In other words, a plurality of PDL openings 167 are arranged in each coating separation opening 149. Figure 3 In the example of , two OLED elements are provided in one coating separation opening 149. As will be described later, the manufacturing of the OLED panel ejects droplets of the organic EL ink into each coating separation opening 149, thereby storing the organic EL ink in the coating separation opening 149. The amount of the organic EL ink to be ejected into the coating separation opening 149 is controlled so that the organic EL ink does not overflow from the coating separation opening 149.

[0056] The inner wall of the coating separation opening 149 is retracted from the PDL opening 167. Therefore, the pixel defining layer 163 is partially exposed between the inner wall of the coating separation opening 149 and the PDL opening 167. As described above, the wettability of the pixel defining layer 163 to the organic EL ink is high, and the wettability of the coating material separation layer 164 to the organic EL ink is low. Therefore, the organic EL ink spreads in the coating separation opening 149, so that the entire surface of the anode electrode 162 is covered with the organic EL ink without any part remaining.

[0057] The solvent of the organic EL ink dries and volatilizes to form the organic light emitting film 165. In the case where the organic light emitting film 165 is composed of multiple layers, the light emitting layer is formed by an inkjet method, and the other layers are formed by vapor deposition or an inkjet method.

[0058] Since each coating separation opening 149 is separated from other coating separation openings 149 by a bank, color mixing of the organic EL ink is prevented. In addition, the low wettability of the coating material separation layer 164 to the organic EL ink more effectively prevents color mixing of the organic EL ink. If the design allows, the wettability of the pixel defining layer 163 and the coating material separation layer 164 does not need to be as described above.

[0059] Above each anode electrode 162, an organic light emitting film 165 is provided. The organic light emitting film 165 is provided in the coating separation opening 149 and contacts the pixel defining layer 163 and the inner wall of the coating separation opening 149. A cathode electrode 166 is provided on the organic light emitting film 165. The cathode electrode 166 is a light transmitting electrode. The cathode electrode 166 transmits a portion of visible light from the organic light emitting film 165. The stacked film of the anode electrode 162, the organic light emitting film 165, and the cathode electrode 166 formed in the PDL opening 167 of the pixel defining layer 163 corresponds to an OLED element.

[0060] The structural packaging unit is disposed above the cathode electrode 166. The structural packaging unit is a multilayer film formed by alternately stacking inorganic thin film layers 182 and 184 and organic thin film layers 181, 183, and 185. The inorganic thin film layers 182 and 184 are used to prevent the penetration of moisture or oxygen, and the inorganic thin film layers 182 and 184 are generally made of silicon nitride or aluminum. The organic thin film layers 181, 183, and 185 are used to prevent damage or serve as a buffer against bending. A λ / 4 plate 187 and a polarizing plate 188 are disposed on the light emitting surface (top surface) of the structural packaging unit to prevent reflection of light incident from the outside.

[0061] Manufacturing method

[0062] An example of a method for manufacturing the OLED display device 10 is described. The method first prepares a support substrate 141, and provides a peeling layer 142 on the support substrate 141 and a flexible substrate 143 on the peeling layer 142. Next, the method forms a multilayer film including alternately stacked inorganic thin film layers 144, 146, and 148 and organic thin film layers 145 and 147. For example, silicon nitride is deposited by chemical vapor deposition (CVD) to form the inorganic thin film layer, and the organic thin film layer is formed by depositing a photosensitive resin.

[0063] Next, the method deposits silicon nitride or photosensitive resin by chemical vapor deposition (CVD) to form a base film 152. Next, the method forms a layer (polysilicon layer) including a channel 155 by a known low-temperature polysilicon TFT manufacturing technology. Specifically, the method forms a polysilicon layer by depositing amorphous silicon using CVD and crystallizing the amorphous silicon by excimer laser annealing (ELA). The method processes the polysilicon film into an island shape and dopes the source region 168 and the drain region 169 to be connected to the source electrode 159 and the drain electrode 160 with a high concentration of impurities to reduce resistance. The polysilicon layer with reduced resistance can also be used to connect components within the display area 125.

[0064] Next, the method deposits silicon oxide on the polysilicon layer including the channel 155 by, for example, CVD to form a gate insulating film 156. Furthermore, the method deposits and patterns a metal by sputtering to form a metal layer including a gate electrode 157.

[0065] In addition to the gate electrode 157, the metal layer also includes a storage capacitor electrode, a scan line 106, and an emission control line. The metal layer can be a single layer made of a material selected from the group consisting of Mo, W, Nb, MoW, MoNb, Al, Nd, Ti, Cu, Cu alloy, Al alloy, Ag, and Ag alloy. Alternatively, the metal layer can have a multilayer structure to reduce wiring resistance. The multilayer structure can include two or more layers, each layer being made of the same or different low-resistance materials selected from Mo, Cu, Al, and Ag.

[0066] When forming the metal layer, the method maintains an offset region in the source region 168 and the drain region 169 with respect to the gate electrode 157. Subsequently, the method dopes the polysilicon film with additional impurities using the gate electrode 157 as a mask to provide a low concentration impurity layer between the source region 168 and the channel 155 and between the drain region 169 and the channel 155.

[0067] Next, the method deposits silicon oxide by CVD to form an interlayer insulating film 158. The method opens contact holes in the interlayer insulating film 158 and the gate insulating film 156 by anisotropic etching. Contact holes 170 and 171 for connecting the source electrode 159 and the drain electrode 160 to the source region 168 and the drain region 169, respectively, are formed in the interlayer insulating film 158 and the gate insulating film 156.

[0068] Next, the method deposits a conductive material into a stacked film such as Ti / Al / Ti by sputtering, and patterns the conductive stacked film to form a metal layer. The metal layer includes a source electrode 159, a drain electrode 160, and the inner walls of contact holes 170 and 171. In addition, data lines 105 and power lines 108 are also formed in the same metal layer.

[0069] Next, the method deposits a photosensitive organic material to form a planarization film 161. Subsequently, the method opens a contact hole 172 connected to the source electrode 159 and the drain electrode 160 of the TFT by exposure and development. The method forms an anode electrode 162 on the planarization film 161 having the contact hole 172. The pattern of the anode electrode 162 corresponds to the pattern of the sub-pixels; anode electrode lines corresponding to the sub-pixel lines are formed.

[0070] The anode electrode 162 includes three layers, i.e., a transparent film made of ITO, IZO, ZnO, In2O3, etc., a reflective film made of a metal such as Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir or Cr or an alloy containing such a metal, and another transparent film as described above. The three-layer structure of the anode electrode 162 is only an example, and the anode electrode 162 may have a two-layer structure. The anode electrode 162 is connected to the drain electrode 160 through the contact hole 172.

[0071] Next, the method deposits silicon oxide by CVD and patterns the film to form a pixel defining layer 163. Patterning forms a plurality of PDL openings 167 (PDL opening pattern) in the pixel defining layer 163. The anode electrode 162 of the sub-pixel is exposed at the bottom of the formed PDL opening 167. The light emitting regions of the respective sub-pixels are isolated by the pixel defining layer 163.

[0072] Next, the method deposits a photosensitive organic resin by spin coating and patterns the photosensitive organic resin to form a coating material separation layer 164. The patterning forms a plurality of coating separation openings 149 (coating separation opening pattern) in the coating material separation layer 164. Each coating separation opening 149 includes a plurality of PDL openings 167 for sub-pixels of the same color.

[0073] Next, the method applies the organic EL ink to the inside of each coating separation opening 149. An example of the method ejects droplets of the organic EL ink into the coating separation opening 149 by inkjet printing. For example, the method ejects a predetermined number of droplets of the organic EL ink of the same color into each PDL opening 167 in the coating separation opening 149. The solvent in the organic EL ink dries, leaving the organic light emitting film 165. The method forms the organic light emitting films 165 for R, G, and B colors on the anode electrode 162.

[0074] The organic light-emitting film 165 may be stacked together with other layers as a multilayer film. For example, a hole injection layer and a hole transport layer may be provided on the anode electrode side of the organic light-emitting film 165, and an electron transport layer and an electron injection layer may be provided on the cathode electrode side. Layers other than the organic light-emitting layer (light-emitting layer) 165 may be formed by an inkjet method or a vapor deposition method. The stacked structure of the organic EL element is determined by design.

[0075] Next, the method deposits a metal material for the cathode electrode 166 onto the substrate exposing the coating material separation layer 164 and the organic light-emitting film 165 (in the opening of the coating material separation layer 164). The metal material deposited on the organic light-emitting film 165 of one sub-pixel serves as the cathode electrode 166 of the sub-pixel in the region of the opening of the pixel defining layer 163.

[0076] The layer of cathode electrode 166 is formed, for example, by vapor deposition of a metal such as Al or Mg or an alloy of the metal. If the resistance of cathode electrode 166 is so high that the uniformity of the brightness of the emitted light is impaired, an additional auxiliary electrode layer may be formed using a material for a transparent electrode such as ITO, IZO, ZnO, or In2O3.

[0077] Next, the method forms a multilayer film (structural packaging unit) including alternately stacked organic thin film layers 181, 183, and 185 and inorganic thin film layers 182 and 184. For example, the inorganic thin film layer is formed by depositing silicon nitride by chemical vapor deposition (CVD), and the organic thin film layer is formed by depositing a photosensitive resin. In addition, the method forms a λ / 4 plate 187 and a polarizing plate 188 on the structural packaging unit.

[0078] △-▽Sub-pixel configuration in the panel

[0079] Figure 4 The sub-pixels arranged in a triangle-▽ pattern are schematically shown. The display area 125 is composed of a plurality of red sub-pixels 41R, a plurality of green sub-pixels 41G, and a plurality of blue sub-pixels 41B arranged in a plane. Figure 4 In FIG. 1 , one of the red sub-pixels, one of the green sub-pixels, and one of the blue sub-pixels are indicated by reference numerals by way of example. Figure 4 The rounded rectangles indicated by the same hatching in the figure represent sub-pixels of the same color. Figure 4 The sub-pixels in FIG. 4 have a rectangular shape, but the sub-pixels may have a desired shape, for example, a hexagonal or octagonal shape.

[0080] The display area 125 includes a plurality of sub-pixel rows extending along the X axis (first axis) and stacked along the Y axis (second axis). Figure 4In the figure, by way of example, one of the red sub-pixel rows is denoted by reference numeral 43R, one of the green sub-pixel rows is denoted by reference numeral 43G, and one of the blue sub-pixel rows is denoted by reference numeral 43B.

[0081] The X-axis and the Y-axis are perpendicular to each other in the plane where the sub-pixels are arranged. The X direction is one of the two opposite directions along the X-axis and is from Figure 4 The Y direction is one of the two opposite directions along the Y axis and runs from Figure 4 The top of the device points to the bottom.

[0082] exist Figure 4 In the example of , each subpixel row is composed of subpixels of the same color arranged at a predetermined pitch. Specifically, each subpixel row 43R is composed of red subpixels 41R arranged along the X axis; each subpixel row 43G is composed of green subpixels 41G arranged along the X axis; and each subpixel row 43B is composed of blue subpixels 41B arranged along the X axis. The red subpixel row 43R, the green subpixel row 43G, and the blue subpixel row 43B are arranged cyclically along the Y axis.

[0083] That is, a sub-pixel row is sandwiched between sub-pixel rows of other two colors. For example, the green sub-pixel row 43G is arranged between the red sub-pixel row 43R and the blue sub-pixel row 43B. Figure 4 In the example of FIG. 4 , the red sub-pixel row 43R, the green sub-pixel row 43G, and the blue sub-pixel row 43B are arranged in this order, and the cycle is repeated. The color order may be different from this example.

[0084] Two adjacent sub-pixel rows are arranged at different positions along the X-axis (when viewed along the Y-axis). That is, when viewed along the Y-axis, each sub-pixel in a sub-pixel row is located between adjacent sub-pixels in the next sub-pixel row. Figure 4 In the example of , each subpixel row is offset by half a pitch relative to the next subpixel row. A pitch is the distance between the centroids of mutually adjacent subpixels in a subpixel row. The subpixels included in the first subpixel row are located at the center between two mutually adjacent subpixels included in the subpixel row adjacent to the first subpixel row.

[0085] The display area 125 includes a plurality of sub-pixel columns extending along the Y axis and arranged side by side along the X axis. Figure 4 In the embodiment of the present invention, two sub-pixel columns are denoted by reference numerals 42A and 42B. One sub-pixel column consists of sub-pixels arranged along the Y axis.

[0086] Each sub-pixel column is composed of red sub-pixels 41R, green sub-pixels 41G, and blue sub-pixels 41B that are cyclically arranged at a predetermined pitch. Figure 4 In the example of FIG. 4 , the red sub-pixel 41R, the blue sub-pixel 41B, and the green sub-pixel 41G are arranged in this order, and the cycle is in the Y direction ( Figure 4 The color order can be different from this example.

[0087] Two sub-pixel columns adjacent to each other are arranged at different positions along the Y axis (when viewed along the X axis); each sub-pixel included in the first sub-pixel column is located between sub-pixels of other two colors included in the sub-pixel column adjacent to the first sub-pixel column. Figure 4 In the example of , each subpixel column is offset by half a pitch relative to the next subpixel column. A pitch is the distance along the Y axis between the centroids of subpixels of the same color. For example, when viewed along the X axis, the green subpixel 41G is located in the middle between the red subpixel 41R and the blue subpixel 41B of the next subpixel column.

[0088] exist Figure 4 In the △-▽ arrangement shown, the brightness centers of the sub-pixels are equidistant from each other to achieve a true resolution display. In this embodiment, for the purpose of description, the sub-pixel line extending along the X axis is referred to as a sub-pixel row, and the sub-pixel line extending along the Y axis is referred to as a sub-pixel column. However, the directions of the sub-pixel rows and sub-pixel columns are not limited thereto.

[0089] Coating separation opening

[0090] Figure 5 An example of a pattern of a coating separation opening of the coating material separation layer 164 is shown. Figure 5 In the embodiment, by way of example, one of the coating separation openings (red coating separation openings) for including a plurality of red sub-pixels (when viewed along the normal to the substrate 100) is denoted by reference numeral 149R; one of the coating separation openings (green coating separation openings) for including a plurality of green sub-pixels is denoted by reference numeral 149G; and one of the coating separation openings (blue coating separation openings) for including a plurality of blue sub-pixels is denoted by reference numeral 149B. Figure 5 The coating separation openings shown with the same hatching in FIG. 1 represent coating separation openings for sub-pixels of the same color.

[0091] Each coating separation opening includes a plurality of sub-pixels of the same color. Figure 5 In the example of , the sub-pixels of the same color in the coating separation openings are included in the same sub-pixel row. Each red coating separation opening 149R includes six consecutive red sub-pixels in the red sub-pixel row. Each green coating separation opening 149G includes six consecutive green sub-pixels in the green sub-pixel row. Each blue coating separation opening 149B includes six consecutive blue sub-pixels in the blue sub-pixel row.

[0092] exist Figure 5 In the example of , the coating separation openings 149R, 149G, and 149B have the same shape. Each coating separation opening includes an area (sub-pixel area) for containing sub-pixels (PDL openings) and an area (connection area) for connecting these sub-pixel areas. The sub-pixels are located in the sub-pixel area. Figure 5 In the figure, by way of example, one of the sub-pixel regions of one red coating separation opening 149R is denoted by reference numeral 491 , and one of the connection regions of the same red coating separation opening 149R is denoted by reference numeral 492 . Figure 5 Each coating separation opening in the example is composed of six sub-pixel regions and five connection regions each connecting sub-pixel regions adjacent to each other.

[0093] In each sub-pixel row, a bank is provided between the coating separation openings adjacent to each other. Figure 5 In the figure, by way of example, two embankments (surrounded by dotted lines) between adjacent red coating separation openings 149R in different red sub-pixel rows are represented by reference numeral 495R; by way of example, one embankment (surrounded by dotted lines) between adjacent green coating separation openings 149G in a green sub-pixel row is represented by reference numeral 495G; by way of example, one embankment (surrounded by dotted lines) between adjacent blue coating separation openings 149B in a blue sub-pixel row is represented by reference numeral 495B.

[0094] like Figure 5 As shown, when viewed along the Y axis, the banks (boundaries) between adjacent coating separation openings in adjacent sub-pixel rows of different colors are arranged at different positions (staggered arrangement). This arrangement makes it difficult to perceive uneven brightness at the ends of the coating separation openings within the display area 125. This feature will be described in detail later.

[0095] Specifically, when viewed along the Y axis, the bank 495R in the red sub-pixel row is offset relative to the bank 495G in the adjacent green sub-pixel row, and further, when viewed along the Y axis, the bank 495R in the red sub-pixel row is offset relative to the bank 495B in the adjacent blue sub-pixel row. Similarly, when viewed along the Y axis, the bank 495G in the green sub-pixel row is offset relative to the bank 495R in the adjacent red sub-pixel row, and further, when viewed along the Y axis, the bank 495G in the green sub-pixel row is offset relative to the bank 495B in the adjacent blue sub-pixel row.

[0096] The offset between the banks in adjacent rows of sub-pixels of different colors is determined by design. In one example, the centers of the banks between the coating separation openings in adjacent rows of sub-pixels of different colors are spaced apart along the X axis by a distance greater than or equal to one sub-pixel pitch (the distance between the centroids of the sub-pixels) so that uneven brightness is difficult to perceive. Figure 5 In the example of , the centers of the banks between the coating separation openings in adjacent sub-pixel rows are 3.5 times or 2.5 times the sub-pixel pitch apart along the X axis. Since each coating separation opening is formed to include six sub-pixels, the distance between the banks in adjacent sub-pixel rows can be made longer.

[0097] Further, in Figure 5 In the example of , when viewed along the Y axis, the banks (boundaries) between adjacent coating separation openings in adjacent sub-pixel lines of the same color are arranged at different positions (staggered arrangement). This arrangement makes it more difficult to perceive uneven brightness at the ends of the coating separation openings in the display area 125. Since the red sub-pixel rows, the green sub-pixel rows, and the blue sub-pixel rows are cyclically arranged along the Y axis, the sub-pixel lines of the same color sandwich two sub-pixel lines of different colors.

[0098] The offset between the banks in adjacent sub-pixel rows of the same color is determined by design. In the example, the centers of the banks between the coating separation openings in adjacent sub-pixel rows of the same color are spaced apart along the X axis by more than or equal to one sub-pixel pitch, thereby making it difficult to perceive uneven brightness. Figure 5 In the example, the centers of the banks between the coating separation openings in adjacent sub-pixel rows of the same color are spaced 3.5 times or 2.5 times apart along the X-axis line as a sub-pixel pitch.

[0099] The shapes of the coating separation openings for sub-pixels of different colors may be different. The shapes of the coating separation openings for sub-pixels of the same color may also be different. For example, among the red coating separation opening 149R, the green coating separation opening 149G, and the blue coating separation opening 149B, the number of sub-pixels included in each coating separation opening may be different.

[0100] Figure 6 1 is a diagram showing unevenness in luminance of sub-pixels in a coating separation opening and a structure in which unevenness in luminance is hardly perceived. Figure 6 The diagram schematically shows a top view of the coating separation opening 149 of the coating material separation layer 164 and the PDL opening 167 of the pixel defining layer 163, a cross-sectional view of a portion of the OLED panel cut along line AA in the top view, the film thickness of the organic light-emitting film (light-emitting layer) 165, and the brightness of the sub-pixel.

[0101] The entire PDL opening 167 is included in the sub-pixel region 491 of the coating separation opening 149. The width (maximum value of the dimension along the Y axis) W2 of the connection region 492 connecting the sub-pixel region 491 is smaller than the width (maximum value of the dimension along the Y axis) W1 of the sub-pixel region 491. When viewed along the Y axis, the sub-pixel region 491 in the sub-pixel row (coating separation opening row) is offset relative to the sub-pixel region 491 in the adjacent sub-pixel row. Since the width W2 of the connection region 492 is smaller than the width W1 of the sub-pixel region 491, the connection region 492 can be appropriately separated from the coating separation opening 149 of the adjacent row.

[0102] As described above, the manufacturing method of the OLED display device applies the organic EL ink 601 to the inside of each coating separation opening 149. In the example, the manufacturing method ejects a droplet to each sub-pixel region 491 (each PDL opening 167). Figure 6 As shown, the distance between sub-pixels of different colors in the △-▽ arrangement is greater than the distance between sub-pixels of different colors in a different pixel arrangement (such as an RGB stripe arrangement).

[0103] Therefore, the risk of color mixing can be reduced.

[0104] The organic EL ink 601 injected into the sub-pixel region 491 spreads throughout the coating separation opening 149 via the connection region 492. Since the wettability of the pixel defining layer 163 is high and the wettability of the coating material separation layer 164 is low as described above, the organic EL ink 601 is appropriately spread on the anode electrode 162 within the coating separation opening 149.

[0105] Since a plurality of pixels are included in one coating separation opening 149, the variation in the film thickness of the organic light-emitting film caused by the variation in the amount of ink ejected from the nozzle is reduced. In addition, by dividing the sub-pixels of each color into a plurality of coating separation openings 149, the variation in the film thickness between the organic light-emitting films generated when the organic EL ink is dried is reduced.

[0106] The organic EL ink 601 is dried in the coating separation opening 149 to form an organic light emitting film 165. An unseparated organic light emitting film is formed in the coating separation opening 149; the organic light emitting film 165 of the sub-pixel is a part of the unseparated organic light emitting film in the coating separation opening 149. The organic light emitting film 165 of each sub-pixel is connected by an organic light emitting film of the same material in the connection region.

[0107] Usually, if Figure 6As shown, the film thickness of the organic light emitting film is different at both ends of the coating separation opening 149. Therefore, the brightness of the sub-pixels at both ends of the coating separation opening 149 tends to be greater than the brightness of the inner sub-pixels. As described above, the coating separation openings 149 are staggered, which makes it difficult to perceive the difference in brightness at both ends of each coating separation opening 149.

[0108] Figure 7 1 shows another example of the pattern of the coating separation opening of the coating material separation layer 164. The sub-pixel arrangement is similar to Figure 5 The example shown is arranged similarly to the △-▽. The pattern of the coating separation opening in this example includes a coating separation opening for including sub-pixels in a plurality of sub-pixel rows. Including sub-pixels in different sub-pixel rows in one coating separation opening causes a reduction in the variation in the film thickness between the organic light-emitting films caused by the variation in the amount of ink ejected from different nozzles and further the variation in the amount of ink ejected from the same nozzle.

[0109] exist Figure 7 In the embodiment, by way of example, one of the red coating separation openings, one of the green coating separation openings, and one of the blue coating separation openings are denoted by reference numerals 149R, 149G, and 149B, respectively. Figure 7 The coating separation openings shown with the same hatching in the figure represent the coating separation openings of the sub-pixels of the same color. A plurality of sub-pixels of the same color are arranged in each coating separation opening. Each coating separation opening includes a sub-pixel region and a connection region connecting the sub-pixel regions, and the width of the connection region is less than the width of the sub-pixel region. Each sub-pixel (PDL opening) is located in a sub-pixel region.

[0110] exist Figure 7 In the example of , the number of sub-pixels included in each red coating separation opening 149R is the same, and the sub-pixels have the same shape. The red coating separation opening 149R includes sub-pixels in two adjacent red sub-pixel rows. Specifically, the red coating separation opening 149R includes six consecutive sub-pixels in one red sub-pixel row and three consecutive sub-pixels in an adjacent red sub-pixel row.

[0111] The number of sub-pixels included in each green coating separation opening 149G is the same, and the sub-pixels have the same shape. The green coating separation opening 149G includes sub-pixels in three adjacent green sub-pixel rows. Specifically, the green coating separation opening 149G includes two consecutive sub-pixels in one green sub-pixel row, two consecutive sub-pixels in another green sub-pixel row, and five consecutive sub-pixels in the green sub-pixel row sandwiched by these green sub-pixel rows.

[0112] The number of sub-pixels included in each blue coating separation opening 149B is the same, and the sub-pixels have the same shape. The blue coating separation opening 149B includes sub-pixels in one blue sub-pixel row. Specifically, the blue coating separation opening 149B includes three consecutive sub-pixels in one blue sub-pixel row.

[0113] exist Figure 7 In the example, the banks (boundaries) in the red sub-pixel row, the banks in the green sub-pixel row, and the banks in the blue sub-pixel row are surrounded by dotted lines and are indicated by reference numerals 495R, 495G, and 495B, respectively. Figure 5 Similarly, when viewed along the Y axis, the banks (boundaries) between the adjacent coating separation openings in the sub-pixel lines of different colors adjacent to each other are arranged at different positions (staggered arrangement). This arrangement makes it difficult to perceive the uneven brightness at the end of the coating separation opening in the display area 125.

[0114] In addition, when viewed along the Y axis, the banks (boundaries) between adjacent coating separation openings in adjacent sub-pixel lines of the same color are arranged at different positions (staggered arrangement). This arrangement makes it more difficult to perceive uneven brightness at the ends of the coating separation openings in the display area 125.

[0115] exist Figure 7 In the example of , the green coating separation opening 149G includes the largest number of sub-pixels, while the blue coating separation opening 149B includes the smallest number of sub-pixels. Green has the highest relative brightness, and blue has the lowest relative brightness; by including a larger number of sub-pixels in the coating separation openings, the variation in brightness between sub-pixels can be reduced. Therefore, the largest number of sub-pixels is included in the green coating separation opening 149G and the smallest number of sub-pixels is included in the blue coating separation opening 149B, so that the perceived brightness variation is reduced. The number of sub-pixels included in the red coating separation opening 149R is less than or equal to the number of sub-pixels included in the green coating separation opening 149G, and is greater than or equal to the number of sub-pixels included in the blue coating separation opening 149B.

[0116] The number of sub-pixels to be included in each coating separation opening 149 is determined by design and is not limited by the above-described structural example. The coating separation openings for sub-pixels of the same color may have different shapes and may include different numbers of sub-pixels.

[0117] As described above, embodiments of the present invention have been described. However, the present invention is not limited to the aforementioned embodiments. Those skilled in the art can easily change, add or transform each element in the aforementioned embodiments within the scope of the present invention. A part of the structure of an embodiment can be replaced by the structure of another embodiment, or the structure of an embodiment can be incorporated into the structure of another embodiment.

Claims

1. An OLED display device, comprising: substrate; a plurality of sub-pixel lines on the substrate, each of the plurality of sub-pixel lines comprising a plurality of sub-pixels of the same color arranged along a first axis; as well as a coating material separation layer on the substrate, the coating material separation layer having a plurality of coating separation openings, Each of the plurality of coating separation openings includes a plurality of sub-pixels of the same color that are continuous in one sub-pixel line, wherein, in each coating separation opening, the organic light emitting films of a plurality of sub-pixels of the same color are connected by an organic light emitting film made of the same material as that of the organic light emitting films of the plurality of sub-pixels, wherein, when viewed along a second axis perpendicular to the first axis, a position of a dam between coating separation openings in each of the plurality of sub-pixel lines is different from a position of a dam between coating separation openings in an adjacent sub-pixel line, The plurality of sub-pixel lines are composed of a red sub-pixel line, a blue sub-pixel line and a green sub-pixel line arranged cyclically along the second axis. When viewed along the second axis, positions of sub-pixels in one of two adjacent sub-pixel lines are different from positions of sub-pixels in the other sub-pixel line. wherein, when viewed along the second axis, sub-pixel lines of different colors are arranged between adjacent sub-pixel lines of the same color, and Each of at least a portion of the plurality of coating separation openings includes a sub-pixel in the adjacent sub-pixel line of the same color.

2. The OLED display device according to claim 1, wherein: A size of a region of sub-pixels connecting each coating separation opening along the second axis is smaller than a size of a region of sub-pixels including each coating separation opening along the second axis.

3. The OLED display device according to claim 1, wherein: When viewed along the second axis, a position of the bank between the coating separation openings in each of the plurality of sub-pixel lines is different from a position of the bank between the coating separation openings in an adjacent sub-pixel line having sub-pixels of the same color.

4. The OLED display device according to claim 1, wherein: When observed along the second axis, the position of the embankment in one of two adjacent sub-pixel lines having sub-pixels of the same color among the multiple sub-pixel lines is offset relative to the position of the embankment in the other sub-pixel line by a distance greater than or equal to the distance between the sub-pixels in the multiple sub-pixel lines.

5. The OLED display device according to claim 1, wherein: All sub-pixels included in each of the plurality of coating separation openings are included in the same sub-pixel line.

6. The OLED display device according to claim 1, wherein: When viewed along the second axis, the position of the embankment in one of two adjacent subpixel lines among the multiple subpixel lines is offset relative to the position of the embankment in the other subpixel line by a distance greater than or equal to the distance between subpixels in the multiple subpixel lines.

7. The OLED display device according to claim 1, in, Each of the plurality of sub-pixel lines is one of a red sub-pixel line, a blue sub-pixel line, and a green sub-pixel line, and Each of the coating separation openings including a sub-pixel of a certain color among the plurality of coating separation openings includes a sub-pixel of the certain color in a different sub-pixel line.

8. The OLED display device according to claim 7, wherein: Among the plurality of coating separation openings, the number of blue sub-pixels included in each coating separation opening is smaller than the number of green sub-pixels included in each coating separation opening.

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