JP2011216778A - Organic el display device, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL display device that is manufactured inexpensively with high accuracy, and to provide a method of manufacturing the same.SOLUTION: A process of forming at least one of a hole transport layer, a light emitting layer and an electron transport layer includes a process of forming a film material layer of the layer and a process of arranging a mask having a predetermined pattern formed thereon at an interval between the mask and the film material layer, and imparting activation energy to the film material layer through the mask while introducing active gas to between the mask and film material layer. The organic EL element is formed by performing patterning by an optical etching method, so that the organic EL display device is manufactured inexpensively with high accuracy compared with a case wherein coating is carried selectively by different colors using vapor-deposition masks.

Description

  The present invention relates to an organic EL display device including an organic EL element and a manufacturing method thereof.

  The organic EL display device includes an organic EL element that is a self-luminous element, and has features such as a wide viewing angle, no need for a backlight, thinning, and high response speed. Therefore, the organic EL display device has attracted attention as a next-generation display device (for example, Patent Document 1).

  In recent years, technologies have been proposed to improve the efficiency of carrier injection into the light-emitting layer by increasing the electrode structure to reduce the electrical barrier, and to improve the light extraction efficiency from the light-emitting layer using the interference effect. Has been.

  However, in order to make an electrode into a multilayer structure, it is necessary to coat an electrode for every luminescent color, and the number of manufacturing processes will increase. In addition, various kinds of vapor deposition masks are necessary for coating differently, but these vapor deposition masks tend to cause dents, scratches, distortions, etc., and may be damaged when the vapor deposition mask is cleaned or inspected. As a result, there is a problem that the manufacturing cost of the organic EL display device is increased. Moreover, when using a vapor deposition mask, there also exists a problem that it cannot pattern with so high precision.

JP 2006-113376 A

  The present invention provides an organic EL display device that can be manufactured with high accuracy at low cost and a method for manufacturing the same.

  According to one aspect of the present invention, first to third organic EL elements that emit light of different colors are provided, and each of the first to third organic EL elements includes a first electrode formed on a substrate and A first carrier injection layer formed on the first electrode, a first carrier transport layer formed on the first carrier injection layer, a light emitting layer formed on the first carrier transport layer, A second carrier transport layer formed on the light emitting layer, a second carrier injection layer formed on the second carrier transport layer, and a second electrode formed on the second carrier injection layer. At least one of the first carrier injection layer, the first carrier transport layer, and the light emitting layer of each of the first to third organic EL elements has substantially the same height and thickness. EL display device characterized by different It is provided.

  According to one aspect of the present invention, the first to third organic EL elements that emit light of different colors are provided, and each of the first to third organic EL elements is formed on a substrate. An electrode, a first carrier injection layer formed on the first electrode, a first carrier transport layer formed on the first carrier injection layer, and a light emitting layer formed on the first carrier transport layer A second carrier transport layer formed on the light emitting layer, a second carrier injection layer formed on the second carrier transport layer, and a second electrode formed on the second carrier injection layer And the height of the lower surface of at least one of the first carrier injection layer, the first carrier transport layer, and the light emitting layer of each of the first to third organic EL elements is substantially the same. , Of the first to third organic EL elements An organic EL display device characterized in that the thickness of the at least one layer that each of the two organic EL elements has is substantially the same, and is different from the thickness of the at least one layer that the other organic EL element has. Provided.

  According to another aspect of the present invention, the step of forming a plurality of first electrodes corresponding to different three colors on the substrate, and the first corresponding to the different three colors on the plurality of first electrodes, respectively. A step of sequentially forming a carrier injection layer and a first carrier transport layer; a step of forming a plurality of light emitting layers that emit light of different colors on the first carrier transport layer corresponding to three different colors; A step of sequentially forming a second carrier transport layer and a second carrier injection layer on each of the plurality of light emitting layers; and a plurality of second electrodes corresponding to the different three colors on the second carrier injection layer. Forming at least one of the first carrier transport layer, the plurality of light emitting layers, and the second carrier transport layer, wherein the step of forming the layer corresponding to the three different colors Forming a film material layer; and A mask in which a predetermined pattern is formed at a distance from the film material layer is disposed, and an active gas is introduced between the mask and the film material layer, and the film material layer is interposed through the mask. There is provided a method for manufacturing an organic EL display device, comprising the step of applying activation energy.

  According to the present invention, an organic EL display device can be manufactured with high accuracy at low cost.

1 is a cross-sectional view of one pixel of an organic EL display device according to a first embodiment of the present invention. Sectional drawing of the organic EL element 50r, 50g, 50b. Process drawing which shows the procedure of the manufacturing process of the organic EL element 50r, 50g, 50b of FIG. Sectional drawing of the manufacturing process of the organic EL elements 50r, 50g, and 50b of FIG. FIG. 5 is a manufacturing process cross-sectional view subsequent to FIG. 4. FIG. 6 is a manufacturing process cross-sectional view following FIG. 5. Manufacturing process sectional drawing following FIG. The figure explaining the photoetching method. The figure which expanded the dashed-dotted line in FIG. The figure which shows the state patterned by the photo-etching method. Sectional drawing of the organic EL element 51r, 51g, 51b which is a modification of FIG. Process drawing which shows the procedure of the manufacturing process of the organic EL element 51r, 51g, 51b of FIG. Sectional drawing of the organic EL element 52r, 52g, 52b which concerns on 2nd Embodiment. Process drawing which shows the procedure of the manufacturing process of the organic EL element 52r, 52g, 52b of FIG. FIG. 14 is a manufacturing process cross-sectional view of the semiconductor device of FIG. 13; FIG. 16 is a sectional view of the manufacturing process following FIG. 15. FIG. 17 is a sectional view of the manufacturing process following FIG. 16. FIG. 18 is a sectional view of the manufacturing process following FIG. 17. FIG. 19 is a manufacturing process cross-sectional view following FIG. 18. FIG. 20 is a sectional view of the manufacturing process following FIG. 19. FIG. 21 is a manufacturing process cross-sectional view following FIG. 20. FIG. 22 is a manufacturing process cross-sectional view following FIG. 21. Sectional drawing of the organic EL element 53r, 53g, 53b which concerns on 3rd Embodiment. FIG. 24 is a process diagram showing a procedure of manufacturing steps of the organic EL elements 53r, 53g, and 53b in FIG. Sectional drawing of the organic EL element 54r, 54g, 54b which concerns on 4th Embodiment. Process drawing which shows the procedure of the manufacturing process of the organic EL element 54r, 54g, 54b of FIG.

  Hereinafter, embodiments of an organic EL display device and a manufacturing method thereof according to the present invention will be specifically described with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view of one pixel of an organic EL display device according to the first embodiment of the present invention. This figure is a top light emitting element type that extracts light emitted from an organic EL element from the top surface, and used a solid sealing technique that does not have a desiccant and a hollow structure and seals the organic EL element with a sealing layer. It is an example of an active matrix organic EL display device. 1 and other drawings do not accurately represent the thickness of each layer.

  1 includes a glass substrate IS, insulator films I1 and I2, TFTs (Thin Film Transistors) 30r, 30g, and 30b, a power supply line PL, video signal lines DLr, DLg, and DLb. Organic EL elements 50r, 50g, and 50b and a partition wall 70 are provided.

  The TFT 30r includes a source region 21r and a drain region 22r, a gate insulating film 23r, and a gate electrode 24r. The source region 21r and the drain region 22r are formed apart from each other in the semiconductor layer on the glass substrate IS, and a channel through which carriers move is formed therebetween. The source electrode of the TFT 30r is connected to the power supply line PL and supplied with a power supply voltage. The gate electrode 24r is supplied with a pixel voltage from the video signal line DLr via a selection element (not shown). The drain electrode is connected to the anode ANDr of the organic EL element 50r. The TFT 30r allows a current corresponding to the pixel voltage to flow through the organic EL element 50r. The TFT 30g and the TFT 30b have the same configuration. The TFTs 30r, 30g, and 30b are covered with the insulator films I1 and I2 and insulated from each other.

  The organic EL element 50r has an anode ANDr, an organic layer ORGr, and a cathode CTD. The anode ANDr is formed using, for example, ITO (Indium Tin Oxide). The organic layer ORGr emits light with a luminance corresponding to the magnitude of the current flowing through the TFT 30r. The cathode CTD is a transparent electrode that transmits light emitted from the organic layer ORGr. FIG. 1 shows an example in which the cathode CTD is commonly used in the organic EL elements 50r, 50g, and 50b.

  The organic EL elements 50r, 50g, and 50b emit light corresponding to the red (R) wavelength, light corresponding to the green (G) wavelength, and light corresponding to the blue (B) wavelength, respectively. Further, the organic layers ORGr, ORGg, and ORGb have different configurations, which will be described later. Except for these points, the organic EL elements 50r, 50g, and 50b have the same configuration.

  The partition wall 70 insulates the adjacent organic EL elements 50r, 50g, and 50b, and is formed of, for example, a resin material. In FIG. 1, bank portions (ribs) are formed so as to surround the organic EL elements 50 r, 50 g, and 50 b, but the bank portions may not be provided. The organic EL elements 50r, 50g, 50b are sealed with a sealing substrate or a sealing film (not shown).

  FIG. 1 is a cross-sectional view of one pixel, and an organic EL display device is configured by arranging a plurality of pixels in a matrix.

  FIG. 2 is a cross-sectional view of the organic EL elements 50r, 50g, and 50b. Actually, the organic EL elements 50r, 50g, and 50b are formed apart from each other as shown in FIG. 1, but for convenience, they are drawn adjacent to each other in FIG.

  The organic EL element 50b includes an anode (first electrode) ANDb, a hole injection layer HIL (Hole Injection Layer), a first hole transport layer HTL (Hole Transport Layer) 1, and a second hole transport layer HTL2. The third hole transport layer HTL3, the blue light emitting layer EML (Emitting Layer) b, the first electron transport layer ETL (Electron Transport Layer) 1, the second electron transport layer ETL2, and the electron injection layer EIL (Electron Injection) Layer) and a cathode (second electrode) CTD. The portion excluding the anode ANDb and the cathode CTD of the organic EL element 50b is the organic layer ORGb in FIG.

  The organic EL element 50g includes an anode ANDg, a hole injection layer HIL, a second hole transport layer HTL2, a third hole transport layer HTL3, a green light emitting layer EMLg, a first electron transport layer ETL1, It has a two-electron transport layer ETL2, an electron injection layer EIL, and a cathode CTD. The portion excluding the anode ANDg and the cathode CTD of the organic EL element 50g is the organic layer ORGg in FIG.

  The organic EL element 50r includes an anode ANDr, a hole injection layer HIL, a third hole transport layer HTL3, a red light emitting layer EMLr, a first electron transport layer ETL1, a second electron transport layer ETL2, and an electron injection. It has a layer EIL and a cathode CTD. The portion excluding the anode ANDr and the cathode CTD of the organic EL element 50r is the organic layer ORGr in FIG.

  The hole injection layer HIL injects holes (first carriers) from the anodes ANDr, ANDg, and ANDb. The hole injection layer HIL is a conductive thin film having high hole injection efficiency, and may be an inorganic material such as amorphous carbon or a conductive organic material. The first to third hole transport layers HTL1 to HTL3 transport holes to the light emitting layers EMLr, EMLg, and EMLb. The electron injection layer EIL injects electrons (second carriers) from the cathode. The first and second electron transport layers ETL1, ETL2 transport electrons to the light emitting layers EMLr, EMLg, EMLb.

  In the present embodiment, there is a step on the upper surface of the hole injection layer HIL included in the organic EL elements 50r, 50g, and 50b. More specifically, although the height of the lower surface of the hole injection layer HIL is formed to be substantially the same, the thicknesses thereof are different. Such a step is formed on the upper surface of the hole injection layer HIL by manufacturing the organic EL elements 50r, 50g, and 50b of FIG. 2 by the photoetching method described below.

  FIG. 3 is a process diagram showing a procedure of manufacturing steps of the organic EL elements 50r, 50g, and 50b of FIG. 2, and FIGS. 4 to 7 are cross-sectional views of manufacturing steps of the organic EL elements 50r, 50g, and 50b of FIG. It is.

  First, a hole injection layer HIL is laminated on the anodes ANDr, ANDg, ANDb by a sputtering method. Further, the film material layers of the first hole transport layer HTL1 and the second hole transport layer HTL2 are sequentially stacked on the hole injection layer HIL by a vapor deposition method (step S1). Thereby, the cross-sectional structure shown in FIG. 4 is obtained.

  Next, the second and first hole transport layers HTL2 and HTL1 on the anodes ANDr and ANDg and a part of the hole injection layer HIL are sequentially etched by the photoetching method (step S2).

  FIG. 8 is a diagram for explaining the photoetching method. FIG. 9 is an enlarged view of a dashed line in FIG. FIG. 10 is a diagram showing a state patterned by the photoetching method. 8 and 9 show a state in which the film material layer HTL1 of the first hole transport layer is stacked on the hole injection layer HIL, and the film material layer HTL1 that is an organic material is patterned by a photoetching method. FIG. 11 shows a step of forming the first hole transport layer HTL1 shown in FIG. 8 to 10, the layer below the hole injection layer HIL and the layer above the film material HTL1 of the first hole transport layer are omitted.

  As shown in FIG. 8, the substrate fixing stage 11 fixes the glass substrate on which the film material layer HTL1 is laminated. A predetermined pattern is formed on the glass mask 12 by the transmission part 12a and the light shielding part 12b. The glass mask 12 is set by adjusting the overlapping position so that the pattern of the glass mask 12 is transferred to a desired region of the film material layer HTL1. As shown in the drawing, the glass mask 12 and the film material layer HTL1 are arranged with a space therebetween. The ultraviolet light source 13 irradiates the film material layer HTL1 with the ultraviolet light 14 through the glass mask 12. At this time, as shown in FIG. 9, only the ultraviolet rays 14 irradiated to the transmission part 12a of the glass mask 12 selectively reach the film material layer HTL1.

  An illumination system lens (not shown) may be provided between the ultraviolet light source 13 and the glass mask 12. By irradiating the ultraviolet ray 14 through the illumination system lens, the pattern transfer accuracy of the glass mask 12 can be improved. Further, a projection system lens (not shown) may be provided between the glass mask 12 and the film material layer HTL1. By irradiating UV light through the projection system lens, the pattern transfer accuracy of the glass mask 12 can be further improved.

  An active gas 15 containing at least oxygen is introduced as a carrier gas between the glass mask 12 (in the case of providing a projection system lens, a projection system lens) and the film material layer HTL1. The concentration of the active gas 15 is optimized in consideration of the distance between the glass mask 12 and the film material layer HTL1, the intensity and wavelength of the irradiated ultraviolet light 14, the etching rate of the material to be etched, and the like. The carrier gas may be an inert gas containing a rare gas such as helium or argon, or a mixed gas of nitrogen and a rare gas.

  The wavelength of the ultraviolet light 14 is set to a wavelength that can activate the active gas 15 efficiently. For example, the ultraviolet light source 13 may be a broad low-pressure mercury lamp including light having wavelengths of 185 nm and 254 nm, a xenon excimer lamp having a wavelength of 172 nm, or an F2 laser having a wavelength of 157 nm. Other light energy beams or lasers may also be used. Note that activation energy may be applied by a method other than ultraviolet irradiation, for example, laser beam irradiation may be performed.

  The active gas 15 absorbs and activates the ultraviolet rays 14 transmitted through the transmission part 12a of the glass mask 12, and is in a highly reactive state. In addition, a portion of the film material layer HTL1 laminated immediately below the transmission portion 12a is irradiated with the ultraviolet rays 14, and dangling bonds are generated on the surface or bonds are loosened, resulting in a highly reactive state.

  The active gas 15 in a highly reactive state is combined with carbon atoms or hydrogen atoms on the surface of the film material layer HTL1, and is desorbed from the film material layer HTL1 as carbon monoxide, carbon dioxide, or water molecules. This carbon monoxide or the like is discharged by the carrier gas.

  On the other hand, the portion of the film material layer HTL1 stacked immediately below the light shielding portion 12b is not irradiated with the ultraviolet rays 14 and therefore is hardly bonded to and detached from the active gas 15.

  As a result, as shown in FIG. 10, only the portion corresponding to the transmissive portion 12a of the glass mask 12 is selectively etched to form the first hole transport layer HTL1. By scanning the glass substrate and the glass mask 12 synchronously, the first hole transport layer HTL1 is formed. At this time, the scanning direction and the introduction direction of the active gas 15 are preferably the same.

  When the hole injection layer HIL formed under the first hole transport layer HTL1 is amorphous carbon or an organic material, when the film material layer HTL1 over the electrodes ANDr and ANDg is etched by the photoetching method, the positive layer thereunder is etched. A part of the hole injection layer HIL is also etched. As a result, as shown in FIGS. 2 and 10, a step is generated on the upper surface of the hole injection layer HIL.

  As described above, in the present embodiment, since the first hole transport layer HTL1 is formed by the photoetching method using the glass mask 12 instead of the separate coating process by vapor deposition using the vapor deposition mask, patterning is performed with higher accuracy. it can.

  Further, since the vapor deposition mask is used in contact with the film material layer, if there are foreign matters or irregularities on the surface of the vapor deposition mask, defects such as circular color mixing and dark spots occur. On the other hand, in the photoetching method, the glass mask 12 and the film material layer are not brought into contact with each other. Further, since the vapor deposition mask is contaminated by contact, for example, the vapor deposition mask must be cleaned every time one or two lots are processed, and after cleaning, the presence or absence of foreign matters and the positional accuracy must be inspected. On the other hand, since the glass mask 12 is not contacted, it is not necessary to clean the glass mask 12 and the manufacturing efficiency is improved. Furthermore, since the glass mask 12 is stronger than the vapor deposition mask, dents, scratches, distortions, and the like are unlikely to occur and handling is easy. Thus, the manufacturing cost of the organic EL display device can be suppressed by processing by the photoetching method.

  Further, as shown in FIG. 10, a side wall portion (taper portion) 16 is formed on the side surface of the first hole transport layer HTL <b> 1, which is modified by taking in oxygen contained in the active gas 15. Since the side wall portion 16 has a large oxygen content, the refractive index is different from that of other portions. In addition, the upper part of the film material layer HTL1 exposed to more active gas has a higher etching rate than the lower part, so that the side wall part 16 is formed in a tapered shape having a narrower width on the upper surface side. Therefore, the side wall part 16 reflects light emitted from the organic EL elements 50r, 50g, and 50b in a direction parallel to the respective layers upward. As a result, the light extraction efficiency can be improved. The angle and refractive index of the side wall portion 16 can be adjusted by the concentration and flow rate of the active gas 15.

  As described above, the second and first hole transport layers HTL2 and HTL1 on the anodes ANDr and ANDg and a part of the hole injection layer HIL are photoetched to obtain the cross-sectional structure shown in FIG. Thereafter, the film material HTL2 of the second hole transport layer is further laminated by vapor deposition (step S3 in FIG. 3), and the cross-sectional structure shown in FIG. 6 is obtained.

  Next, the film material HTL2 on the anode ANDr and a part of the hole injection layer HIL are etched by a photoetching method (step S4). Thereby, the cross-sectional structure shown in FIG. 7 is obtained. At this time, a step is generated between the hole injection layer HIL on the anode ANDr and the hole injection layer HIL on the anode ANDg. A side wall (not shown) is formed on the side surface of the second hole transport layer HTL2.

  As shown in FIG. 7, the thicknesses of the hole injection layers on the anodes ANDr, ANDg, and ANDb are different from each other.

  Thereafter, the third hole transport layer HTL3 is stacked by a vapor deposition method (step S5). Further, the light emitting layers EMLr, EMLg, and EMLb are respectively stacked on the upper surfaces of the anodes ANDr, ANDg, and ANDb (step S6). Subsequently, the first and second electron transport layers ETL1 and ETL2 and the electron injection layer EIL are laminated on each of them by vapor deposition (step S7). Further, the cathode CTD is laminated to form the organic EL elements 50r, 50g, and 50b having the cross-sectional structure shown in FIG.

  As described above, a step is generated on the upper surface of the hole injection layer HIL. By appropriately designing this step according to the wavelength of light extracted from each organic EL element 50r, 50g, 50b, the film thickness and refractive index of each layer from the hole injection layer HIL to the electron injection layer EIL in FIG. The light extraction efficiency from the organic EL elements 50r, 50g, and 50b can be improved. More specifically, the thickness of this step is determined by resonance between light emitted upward from each of the light emitting layers EMLr, EMLg, and EMLb and light reflected downward from the lower surface. It is better to set the thickness to be amplified. A metal reflective layer (not shown) such as aluminum or silver may be provided under the anodes ANDr, ANDg, and ANDb so that light emitted downward can be easily reflected upward.

  FIG. 11 is a cross-sectional view of organic EL elements 51r, 51g, 51b, which is a modification of FIG. The organic EL elements 51r, 51g, and 51b have a common fourth hole transport layer HTL4 between the hole injection layer HIL and the first hole transport layer HTL1. There is a step in the fourth hole transport layer HTL4, not in the hole injection layer HIL.

  FIG. 12 is a process diagram showing a procedure of manufacturing steps of the organic EL elements 51r, 51g, 51b of FIG. Hereinafter, a description will be given focusing on differences from FIG. 2 and FIG. 3.

  First, the electron injection layer HIL and the fourth, first, and second hole transport layers HTL4, HTL1, and HTL2 are sequentially stacked on the anodes ANDr, ANDg, and ANDb (step S1 '). Next, the second and first hole transport layers HTL2 and HTL1 on the anodes ANDr and ANDg and a part of the fourth hole transport layer HTL4 are sequentially etched by a photoetching method (step S2 ').

  Thereafter, a film material HTL2 for the second hole transport layer is further stacked (step S3). Subsequently, the second hole transport layer HTL2 on the anode ANDr and a part of the fourth hole transport layer HTL4 are sequentially etched by the photoetching method (step S4 '). The subsequent manufacturing steps are the same as those in FIG. Thus, the organic EL elements 51r, 51g, 51b having the structure shown in FIG. 11 are obtained.

  In addition to FIGS. 2 and 11, an organic EL element having a step in at least one of the hole injection layer HIL, the hole transport layer HTL, and the light emitting layer EML may be formed. Also in this case, the thickness of the step may be adjusted so that the light extraction efficiency is increased by the resonance operation.

  Thus, in the first embodiment, patterning is performed by a photoetching method to form an organic EL element. Therefore, an organic EL display device can be manufactured with low cost and high accuracy as compared with the case of performing separate coating using a vapor deposition mask. Further, since a step is formed in at least one of the hole injection layer HIL, the hole transport layer HTL, and the light emitting layer EML, the light emitting elements EMLr, EMLg, and EMLb are formed by resonance operation using the thickness of the step. Can amplify the light emitted from the light and improve the light extraction efficiency. Further, since the side wall portion is formed on the side surface of the layer formed by the photoetching method, the organic EL element reflects light emitted from the side wall portion in a direction parallel to each layer to the upper surface, thereby further improving the light extraction efficiency. Can be improved.

(Second Embodiment)
In the second embodiment described below, a more specific example of the organic EL element is shown.

  FIG. 13 is a cross-sectional view of the organic EL elements 52r, 52g, and 52b according to the second embodiment.

  The organic EL element 52b includes an anode ANDb, a hole injection layer HIL, a first hole transport layer HTL1, a second hole transport layer HTL2, a third hole transport layer HTL3, a blue light emitting layer EMLb, The first electron transport layer ETL1, the second electron transport layer ETL2, the electron injection layer EIL, and the cathode CTD.

  The organic EL element 52g includes an anode ANDg, a hole injection layer HIL, a first hole transport layer HTL1, a third hole transport layer HTL3, a green light emitting layer EMLg, a first electron transport layer ETL1, It has a two-electron transport layer ETL2, an electron injection layer EIL, and a cathode CTD.

  The organic EL element 52r includes an anode ANDr, a hole injection layer HIL, a first hole transport layer HTL1, a third hole transport layer HTL3, a red light emitting layer EMLr, a blue light emitting layer EMLb, and first electrons. It has a transport layer ETL1, a second electron transport layer ETL2, an electron injection layer EIL, and a cathode CTD.

  In the organic EL elements 52r, 52g, and 52b of FIG. 13, there are steps on the upper surfaces of the first and third hole transport layers HTL1 and HTL3. More specifically, the thickness of the first hole transport layer HTL1 on the anode ANDr and the thickness of the first hole transport layer HTL1 on the anode ANDg are substantially the same, but the first hole transport layer HTL1 on the anode ANDb. The thickness is different from these.

  FIG. 14 is a process diagram showing a procedure of manufacturing steps of the organic EL elements 52r, 52g, and 52b of FIG. 13, and FIGS. 15 to 22 are cross-sectional views of manufacturing steps of the organic EL elements 52r, 52g, and 52b of FIG. It is.

  First, the electron injection layer HIL is laminated on the anodes ANDr, ANDg, ANDb by sputtering. Further, the first hole transport layer HTL1 and the film material layer HTL2 of the second hole transport layer are stacked on the electron injection layer HIL by a vapor deposition method (step S11). Thereby, the cross-sectional structure shown in FIG. 15 is obtained.

  Next, the film material layer HTL2 on the anodes ANDr and ANDg is etched by a photoetching method to form the second hole transport layer HTL2 on the anode ANDb (step S12). Thereby, the cross-sectional structure shown in FIG. 16 is obtained. At this time, a part of the first hole transport layer HTL1 on the anodes ANDr and ANDg is also etched, and between the first hole transport layer HTL1 on the anode ANDb and the first hole transport layer HTL1 on the anode ANDg. A step occurs. A side wall (not shown) is formed on the side surface of the second hole transport layer HTL2.

  Thereafter, the third hole transport layer HTL3 and the film material layer EMLr of the red light emitting layer are laminated on the first and second hole transport layers HTL1 and HTL2 by a vapor deposition method (step S13), and FIG. The cross-sectional structure shown is obtained.

  Next, the film material layer EMLr on the anodes ANDg and ANDb is etched by a photoetching method to form a red light emitting layer EMLr on the anode ANDr (step S14). Thereby, the cross-sectional structure shown in FIG. 18 is obtained. At this time, a part of the third hole transport layer HTL3 on the anode ANDg is also etched, and a step is formed between the third hole transport layer HTL3 on the anode ANDr and the third hole transport layer HTL3 on the anode ANDg. Arise. A side wall (not shown) is formed on the side surface of the red light emitting layer EMLr.

  Thereafter, the film material layer EMLg of the green light emitting layer is laminated by vapor deposition (step S15), and the cross-sectional structure shown in FIG. 19 is obtained. Next, the film material layer EMLg on the anodes ANDr and ANDb is etched by a photoetching method to form a green light emitting layer EMLg on the anode ANDg (step S16). Thereby, the cross-sectional structure shown in FIG. 20 is obtained.

  Thereafter, the film material layer EMLb of the blue light emitting layer is laminated by vapor deposition (step S17), and the cross-sectional structure shown in FIG. 21 is obtained. Next, the film material layer EMLb on the anode ANDg is patterned by a photoetching method to form a blue light emitting layer EMLb on the anodes ANDr and ANDb (step S18). Thereby, the cross-sectional structure shown in FIG. 22 is obtained. At this time, a side wall (not shown) is formed on the side surface of the blue light emitting layer EMLb.

  Thereafter, the first and second electron transport layers ETL1, ETL2, the electron injection layer EIL, and the cathode CTD are laminated by vapor deposition (step S19), and the organic EL elements 52r, 52g, and 52b shown in FIG. 13 are obtained.

  Thus, in the second embodiment, each film material layer is patterned by a photoetching method without performing separate coating using a vapor deposition mask. Therefore, an organic EL display device can be manufactured with low cost and high accuracy.

(Third embodiment)
The third embodiment described below is different from the second embodiment in the structure of the organic EL element 53g.

  FIG. 23 is a cross-sectional view of organic EL elements 53r, 53g, and 53b according to the third embodiment. The organic EL element 53g has a blue light emitting layer EMLb between the green light emitting layer EMLg and the first electron transport layer ETL1. This point is different from the organic EL element 52g in the second embodiment. The structures of the organic EL elements 53r and 53b are the same as those of the organic EL elements 52r and 52b in the second embodiment, and there are steps on the upper surfaces of the first and third hole transport layers HTL1 and HTL3.

  FIG. 24 is a process diagram showing a procedure of manufacturing steps of the organic EL elements 53r, 53g, and 53b of FIG. Steps S11 to S17 in FIG. 24 are the same as in the second embodiment, and the cross-sectional view shown in FIG. 21 is obtained. Thereafter, the first and second electron transport layers ETL1, ETL2, the electron injection layer EIL, and the cathode CTD are stacked without etching the blue light-emitting layer EMLb on the green light-emitting layer EMLg (step S19), and the organic layers shown in FIG. EL elements 53r, 53g, and 53b are obtained.

  In this case, the blue light emitting layer EMLb remaining in the organic EL element 53g does not emit light and functions as an electron transport layer. Further, by adjusting the thickness of the blue light emitting layer EMLb, the light emission efficiency of the light emitted from the organic EL element 53g can be improved.

  Thus, in the third embodiment, since the blue light-emitting layer EMLb on the green light-emitting layer EMLg is not etched, the number of manufacturing steps can be reduced as compared with the second embodiment, and an organic EL display device can be manufactured at a lower cost. .

(Fourth embodiment)
In the fourth embodiment described below, each organic EL element has a hole blocking layer (carrier blocking layer) HBL (Hole Blocking Layer).

  FIG. 25 is a cross-sectional view of organic EL elements 54r, 54g, and 54b according to the fourth embodiment. Each organic EL element 54r, 54g, 54b has a hole blocking layer HBL, and the third hole transport layer HTL3 of the organic EL element 54b is more than the third hole transport layer HTL3 of the other organic EL elements 54r, 54g. The thick point is different from the third embodiment.

  When there is no hole blocking layer HBL, the electron transport layer ETL deteriorates due to holes leaked from the light emitting layer EML to the electron transport layer ETL, and the light emission luminance is lowered. On the other hand, the hole blocking layer HBL of the present embodiment keeps holes injected from the anode in the light emitting layer EML and suppresses reaching the electron transport layer ETL. Therefore, the number of holes leaking into the electron transport layer ETL is reduced, and deterioration of the organic EL element can be suppressed. As a result, the lifetime of the organic EL elements 54r, 54g, and 54b can be extended.

  In addition, by forming the third hole transport layer HTL3 of the organic EL element 54b thick, it is possible to reduce the burn-in of the blue pixels that are easily burned.

  FIG. 26 is a process diagram showing a procedure of manufacturing steps of the organic EL elements 54r, 54g, and 54b of FIG.

  Steps S11 and S12 are the same as in the second embodiment. Thereafter, the film material layer HTL3 of the third hole transport layer is laminated by a vapor deposition method (step S21). Next, a part of the film material layer HTL3 on the anodes ANDr and ANDg is etched by a photoetching method to form the third hole transport layer HTL3 (step S22). Thereby, the third hole transport layer HTL3 on the anode ANDb is thicker than the third hole transport layer HTL3 on the anodes ANDr and ANDg. A side wall (not shown) is formed on the side surface of the third hole transport layer HTL3.

  Thereafter, the film material layer EMLr of the red light emitting layer is laminated by vapor deposition (step S13 '). The subsequent steps up to step S17 are the same as in the third embodiment. Thereafter, the hole blocking layer HBL, the first and second electron transport layers ETL1 and ETL2, the electron injection layer EIL, and the cathode CTD are laminated on the blue light emitting layer EMLb by a vapor deposition method (step S19 ′). The organic EL elements 54r, 54g, and 54b shown are obtained.

  Thus, in the fourth embodiment, since the hole blocking layer HBL is provided, the life of the organic EL display device can be extended. Further, since the third hole transport layer HTL3 of the organic EL element 54b is formed thick, it is possible to reduce the burn-in of the blue pixels.

  In each of the above-described embodiments, an example in which all layers are patterned by a photoetching method has been described. However, at least one of a hole transport layer, a light emitting layer, and an electron transport layer is formed by a photoetching method, Other layers may be formed by other methods (for example, vapor deposition using a vapor deposition mask).

  Based on the above description, those skilled in the art may be able to conceive additional effects and various modifications of the present invention, but the aspects of the present invention are not limited to the individual embodiments described above. Absent. Various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

50r to 54r, 50g to 54g, 50b to 54b Organic EL elements ANDr, ANDg, ANDb Anode HIL Hole injection layer HTL1 to HTL4 Hole transport layer EMLr, EMLg, EMLb Light emitting layer HBL Hole blocking layer ETL1, ETL2 Electron transport layer EIL Electron Injection Layer CTD Cathode 12 Mask 13 Ultraviolet Light Source 14 Ultraviolet 15 Activated Gas 16 Side Wall

Claims (6)

First to third organic EL elements that emit light of different colors,
Each of the first to third organic EL elements is
A first electrode formed on the substrate;
A first carrier injection layer formed on the first electrode;
A first carrier transport layer formed on the first carrier injection layer;
A light emitting layer formed on the first carrier transport layer;
A second carrier transport layer formed on the light emitting layer;
A second carrier injection layer formed on the second carrier transport layer;
A second electrode formed on the second carrier injection layer,
At least one of the first carrier injection layer, the first carrier transport layer, and the light emitting layer included in each of the first to third organic EL elements has substantially the same height and different thickness. An organic EL display device. First to third organic EL elements that emit light of different colors,
Each of the first to third organic EL elements is
A first electrode formed on the substrate;
A first carrier injection layer formed on the first electrode;
A first carrier transport layer formed on the first carrier injection layer;
A light emitting layer formed on the first carrier transport layer;
A second carrier transport layer formed on the light emitting layer;
A second carrier injection layer formed on the second carrier transport layer;
A second electrode formed on the second carrier injection layer,
The heights of the lower surfaces of at least one of the first carrier injection layer, the first carrier transport layer, and the light emitting layer of each of the first to third organic EL elements are substantially the same.
The thickness of the at least one layer that each of two of the first to third organic EL elements has is substantially the same, and the thickness of the at least one layer that the other one of the organic EL elements has Are different from each other in an organic EL display device.   Each of the at least one layer has a thickness in which light directed directly from the light emitting layer toward the second electrode and light directed toward the second electrode after being reflected on the first electrode side perform resonance operation. The organic EL display device according to claim 1, wherein the organic EL display device is set.   4. The organic EL display device according to claim 1, wherein each of the at least one layer has a tapered portion whose width is narrower toward an upper surface side. 5.   Each of the first to third organic EL elements prevents carriers supplied from the first electrode from reaching the second carrier transport layer between the light emitting layer and the second carrier transport layer. The organic EL display device according to claim 1, further comprising a carrier blocking layer. Forming a plurality of first electrodes corresponding to three different colors on a substrate;
Forming a first carrier injection layer and a first carrier transport layer corresponding to three different colors in order on the plurality of first electrodes,
Forming a plurality of light emitting layers that emit light of different colors on the first carrier transport layer corresponding to three different colors;
Forming a second carrier transport layer and a second carrier injection layer in order on each of the plurality of light emitting layers;
Forming a plurality of second electrodes corresponding to the three different colors on the second carrier injection layer,
Forming at least one of the first carrier transport layer, the plurality of light emitting layers, and the second carrier transport layer,
Forming a film material layer corresponding to the three different colors;
A mask in which a predetermined pattern is formed at a distance from the film material layer is disposed, and an active gas is introduced between the mask and the film material layer, and the film material layer is interposed through the mask. And a step of applying activation energy. A method of manufacturing an organic EL display device, comprising:

Images