JP2006260950A - Organic el device, manufacturing method of the same, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL device having a construction hardly generating unevenness of brightness even if unevenness of film thickness is generated on an organic material formed inside a barrier rib. <P>SOLUTION: The organic EL device has barrier rib parts 112 demarcating a plurality of pixel areas R, G, B on a substrate 2, and at least an anode 111, an organic EL layer 119b, and a cathode 12 are laminated on the pixel areas R, G, B. The organic EL layer 110b is formed in a region surrounded by a barrior rib 112. The cathode 12 has a lamination structure formed by laminating a first cathode 12a having relatively small work function and a second cathode 12b having relatively large work function in this sequence from the organic EL layer 110 side. Out of the cathode 12, at least peripheral edge part of the first cathode 12a is located inside the peripheral edge part of the organic EL layer 110b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic EL device, a method for manufacturing an organic EL device, and an electronic apparatus.

As an organic EL device (organic electroluminescence device) that is a self-luminous display device, there is a configuration in which a hole transport layer or a light emitting layer made of an organic material is sandwiched between an anode and a cathode. In manufacturing such an organic EL device, the hole transport layer and the light emitting layer using an organic material are preferably formed by a spin coat method or an ink jet method. In particular, when the inkjet method is used as in Patent Document 1, a bank is formed on the anode in order to form a film on a target pixel, and an organic material (hole transport layer forming material) is formed by forming such a bank. Alternatively, the droplets containing the light emitting layer forming material) and the solvent stably land in the pixel.
JP-A-10-153967

  When the ink jet method as in Patent Document 1 is used, a target hole transport layer or a light emitting layer is formed through a solvent removal process after landing a droplet in a pixel. Here, when a film is formed from a droplet state through a drying step, the affinity between the pixel and the surface state on the anode is determined between the central portion and the outer peripheral portion (peripheral end portion) of the pixel surrounded by the bank. Due to the difference, the film thickness may vary. In particular, the film thickness tends to be large at the outer periphery of the pixel and small at the center of the pixel.

  The relationship between the film thickness of the light-emitting layer and the current tends to be almost the same as that of a conductive polymer that is generally said, and current variation can occur due to the square to the cube of the film thickness. Considering that the relationship between current and luminance is close to linear, in order to suppress variations in luminance in a certain range, variations in film thickness must be strictly suppressed. On the other hand, as long as the bank is formed, it is difficult to avoid the variation in film thickness that occurs at the central portion and the outer peripheral portion of the pixel as described above.

  The present invention has been made in view of the above-described problems, and has a configuration in which luminance variation hardly occurs even when the film thickness of the organic material formed in the bank (partition wall) varies. Another object is to provide an organic EL device and a manufacturing method thereof. It is another object of the present invention to provide a highly reliable electronic device including such an organic EL device.

  In order to solve the above-described problems, an organic EL device according to the present invention is formed with a partition portion for partitioning a plurality of pixel regions on a substrate. The pixel region includes at least an anode, an organic EL layer, and an organic EL layer. The cathode is laminated and the organic EL layer is formed in a region surrounded by the partition wall, while the cathode works relatively with the first cathode having a relatively small work function. A second cathode having a large function has a laminated structure in which the organic EL layer is laminated in this order, and at least the first cathode of the cathodes has an outer edge of the first cathode. It is formed so that it may be located inside the outer edge of the layer.

  According to such an organic EL device, since the outer edge of the first cathode constituting the cathode is located inside the outer edge of the organic EL layer, the formation area of the first cathode is a plane of the formation area of the organic EL layer. At least one of the first cathodes is not formed at a position on the inner side, that is, at a position overlapping the outer peripheral portion of the organic EL layer in plan view. Therefore, no electrons are injected into the outer peripheral portion of the organic EL layer, or substantially no electrons are injected (that is, electrons effective for light emission are not injected). As a result, in the organic EL layer formed in the pixel region, the outer periphery of the organic EL layer can be used even when the film thickness varies (difference) between the central portion and the outer peripheral portion of the pixel region for manufacturing reasons. By not injecting (or substantially not injecting) electrons into the portion, the outer peripheral portion does not contribute to light emission. As a result, uniform light emission can be obtained without luminance variations caused by variations in film thickness. In addition, there is no variation in lifetime due to variations in luminance, and as a result, the lifetime of the organic EL device can be improved.

  In the organic EL device of the present invention, the second cathode may be formed across the pixel regions. That is, if the first cathode is patterned, electrons effective for light emission cannot be injected into the organic EL layer, and the second cathode having a relatively large work function has a pattern shape following the first cathode. In addition, the entire surface can be formed in a solid shape across each pixel region. In this case, the formation is very simple. As the first cathode and the second cathode constituting the cathode, for example, a cathode in which the first cathode is made of calcium and the second cathode is made of aluminum can be used.

  On the other hand, the anode may be configured as a pixel electrode patterned for each pixel region on the substrate. In the present invention, the outer edge of the anode may be any of the inner side, the outer side, and the outer edges of the organic EL layer overlapping each other.

  In addition, an electron injection layer made of lithium fluoride may be formed between the organic EL layer and the first cathode. When such an electron injection layer made of lithium fluoride is interposed between the first cathode and the organic EL layer, it is possible to promote electron injection from the first cathode to the organic EL layer. Such an electron injection layer can also be formed in a solid shape across the pixel regions, but, like the first cathode, the outer edge of the electron injection layer is inside the outer edge of the organic EL layer. It is preferable that it is formed so that it may be located in. This is because light emission at the outer peripheral portion of the organic EL layer can be more reliably suppressed.

  Further, an electron injection shielding layer for shielding electron injection is formed between the organic EL layer and the cathode, and the electron injection shielding layer is located at a position overlapping the outer peripheral portion of the organic EL layer in plan view. It can be formed selectively. In this case, among the organic EL layers, electron injection is shielded at the outer peripheral portion where the electron injection shielding layer is formed, so that light emission at the outer peripheral portion of the organic EL layer can be more reliably suppressed.

  In the organic EL device having the electron injection shielding layer as described above, the cathode has translucency, and light emitted from the organic EL layer is emitted from the cathode side, and the electron injection shielding is performed. The layer may have a light shielding property. In this case, even if light emission occurs at the outer peripheral portion of the organic EL layer, the electron injection shielding layer shields the light, so that light can be prevented from passing to the cathode side, and luminance variation can be prevented from occurring in the pixel region. It becomes possible to do.

  The organic EL layer may be formed by applying a liquid material in which an organic material constituting the organic EL layer is dissolved or dispersed in a solvent to a region surrounded by the partition wall. . When the liquid phase method in which an organic EL layer is formed by applying a liquid material to the region surrounded by the partition wall, the thickness of the organic EL layer depends on the degree of wettability with respect to the partition wall. However, if the configuration of the present invention is adopted for an organic EL device including an organic EL layer formed by such a liquid phase method, the problem of non-uniform film thickness is caused. It can be solved as described above. As the liquid phase method, specifically, a droplet discharge method using a droplet discharge device (inkjet device) can be exemplified.

  Next, in order to solve the above-described problem, the organic EL device manufacturing method of the present invention includes a partition wall forming step for forming a partition wall for partitioning a plurality of pixel regions on a substrate, and an anode on the substrate. An organic EL layer forming step for forming an organic EL layer on the anode, and a cathode forming step for forming a cathode on the organic EL layer, the organic EL layer forming step comprising: The cathode includes a step of applying a liquid material in which an organic material constituting the organic EL layer is dissolved or dispersed in a solvent to a region surrounded by the partition wall, and a step of drying the applied liquid material. Forming the first cathode having a relatively low work function on the organic EL layer, such that the outer edge of the first cathode is positioned inside the outer edge of the organic EL layer; and Relatively on the first cathode; Characterized in that it comprises the steps of forming a large second cathode things function, a.

  By such a method, the above-described organic EL device of the present invention can be suitably manufactured. Note that in the organic EL layer forming process, the selective discharge of the liquid material into the region surrounded by the partition wall can be performed more reliably if the droplet discharge method using a droplet discharge device (inkjet device) is employed. It becomes like this.

  Further, in the step of forming the second cathode, it can be formed across each pixel region by vapor deposition or the like. That is, if a conductive metal material such as aluminum constituting the second cathode is formed on the entire surface of the substrate across the respective pixel regions by vapor deposition, the formation of the second cathode becomes very simple.

  On the other hand, the anode forming step can be performed prior to the partition wall forming step, and in this case, the anode can be patterned for each pixel region on the substrate. Such an anode is configured as a pixel electrode, and it is possible to control energization of each pixel electrode via, for example, a TFT (thin film transistor) as a switching element. Note that after the anode is formed, the partition wall portion is selectively formed in a form surrounding the anode, that is, in a region where the anode is not formed. Here, the partition wall may be formed so as to partially overlap with the outer periphery of the anode. As a result, it is possible to eliminate the problem that a gap is generated between the anode and the partition wall portion, and the pixel region can be surely partitioned by the partition wall portion.

  Next, in order to solve the above-described problems, an electronic apparatus according to the present invention includes the organic EL device. In this case, it is possible to provide a highly reliable electronic device with little emission unevenness.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing to be referred to, the scale may be different for each layer or each member in order to make the size recognizable on the drawing.

(First embodiment)
FIG. 1 shows an embodiment of an organic EL device of the present invention, and is a diagram schematically showing an active matrix type organic EL device in particular. Note that the organic EL device 1 shown in FIG. 1 employs an active driving method using thin film transistors.

  An organic EL device 1 includes a circuit element unit 14 including a thin film transistor as a circuit element, an anode (pixel electrode) 111, a functional layer 110 including an organic EL layer (organic EL element), and a cathode (counter electrode) on a substrate 2. 12 and the sealing portion 3 and the like are sequentially laminated.

  As the substrate 2, a glass substrate is used in this example. In addition to the glass substrate, various known substrates such as a silicon substrate, a quartz substrate, a ceramic substrate, a metal substrate, a plastic substrate, and a plastic film substrate are used. In the substrate 2, a plurality of pixel areas A as light emitting areas are arranged in a matrix, and when performing color display, for example, corresponding to each color of red (R), green (G), and blue (B) The pixel area A to be configured is configured in a predetermined arrangement. In each pixel region A, an anode 111 is arranged, and in the vicinity thereof, a signal line 132, a power supply line 133, a scanning line 131, and other anode scanning lines (not shown) are arranged. As the planar shape of the pixel region A, an arbitrary shape such as a circle or an oval is applied in addition to the rectangle shown in the figure.

  The sealing portion 3 prevents water and oxygen from entering and prevents the cathode 12 or the functional layer 110 from being oxidized. The sealing portion 3 is applied to the substrate 2 and the sealing is bonded to the substrate 2. Substrate 3b (sealing can) is included. As the material of the sealing resin, for example, a thermosetting resin or an ultraviolet curable resin is used, and in particular, an epoxy resin that is one kind of thermosetting resin is preferably used. The sealing resin is annularly applied to the periphery of the substrate 2 and is applied by, for example, a microdispenser. The sealing substrate 3b is made of glass, metal, or the like, and the substrate 2 and the sealing substrate 3b are bonded together via a sealing resin.

FIG. 2 shows a circuit structure of the organic EL device 1.
On the substrate 2 shown in FIG. 1, a plurality of scanning lines 131 as shown in FIG. 2, a plurality of signal lines 132 extending in a direction intersecting the scanning lines 131, and a plurality of signals extending in parallel to the signal lines 132. The power supply line 133 is wired. Further, the pixel region A is formed at each intersection of the scanning line 131 and the signal line 132.
For example, the data line driving circuit 103 including a shift register, a level shifter, a video line, and an analog switch is connected to the signal line 132. The scanning line 131 is connected to a scanning side driving circuit 104 including a shift register and a level shifter.

  In the pixel region A, a first thin film transistor 123 for switching in which a scanning signal is supplied to the gate electrode via the scanning line 131 and a holding for holding an image signal supplied from the signal line 132 via the thin film transistor 123. A capacitor 135, a second driving thin film transistor 124 to which an image signal held by the holding capacitor 135 is supplied to the gate electrode, and the power line 133 when electrically connected to the power line 133 through the thin film transistor 124 An anode (pixel electrode) 111 into which a drive current flows from and a functional layer 110 sandwiched between the anode 111 and the cathode (counter electrode) 12 are provided. The functional layer 110 includes an organic EL layer as an organic EL element.

  In the pixel region A, when the scanning line 131 is driven and the first thin film transistor 123 is turned on, the potential of the signal line 132 at that time is held in the holding capacitor 135, and the second potential is changed depending on the state of the holding capacitor 135. The conductive state of the thin film transistor 124 is determined. In addition, a current flows from the power supply line 133 to the anode 111 through the channel of the second thin film transistor 124, and further a current flows to the cathode (counter electrode) 12 through the functional layer 110. The functional layer 110 emits light according to the amount of current at this time.

FIG. 3 is an enlarged view showing a cross-sectional structure of the display area in the organic EL device 1. FIG. 3 shows a cross-sectional structure of three pixel regions corresponding to red (R), green (G), and blue (B) colors. As described above, the organic EL device 1 includes the circuit element unit 14 in which circuits such as TFTs are formed on the substrate 2, the anode (pixel electrode) 111, the light emitting element unit 11 in which the functional layer 110 is formed, and A cathode (counter electrode) 12 is sequentially laminated.
In the organic EL device 1, light emitted from the functional layer 110 to the substrate 2 side passes through the circuit element unit 14 and the substrate 2 and is emitted to the lower side (observer side) of the substrate 2, and the functional layer 110. The light emitted from the opposite side of the substrate 2 is reflected by the cathode 12, passes through the circuit element unit 14 and the substrate 2, and is emitted to the lower side (observer side) of the substrate 2.

In the circuit element portion 14, a base protective film 2c made of a silicon oxide film is formed on the substrate 2, and an island-shaped semiconductor film 141 made of polycrystalline silicon is formed on the base protective film 2c. Note that a source region 141a and a drain region 141b are formed in the semiconductor film 141 by high concentration P ion implantation. A portion where P is not introduced is a channel region 141c.
Further, a transparent gate insulating film 142 that covers the base protective film 2c and the semiconductor film 141 is formed in the circuit element portion 14, and a gate electrode 143 made of Al, Mo, Ta, Ti, W, or the like is formed on the gate insulating film 142. (Scanning lines) are formed, and a transparent first interlayer insulating film 144 a and a second interlayer insulating film 144 b are formed on the gate electrode 143 and the gate insulating film 142. The gate electrode 143 is provided at a position corresponding to the channel region 141 c of the semiconductor film 141. Contact holes 145 and 146 are formed through the first and second interlayer insulating films 144a and 144b and connected to the source and drain regions 141a and 141b of the semiconductor film 141, respectively.

On the second interlayer insulating film 144b, a transparent anode 111 made of ITO or the like is patterned and formed in a predetermined shape, and one contact hole 145 is connected to the anode 111.
The other contact hole 146 is connected to the power line 133.
In this way, the driving thin film transistor 123 connected to each anode 111 is formed in the circuit element section 14. The circuit element unit 14 is also formed with the storage capacitor 135 and the switching thin film transistor 124 described above, but these are not shown in FIG.

  The light emitting element unit 11 is mainly configured by a functional layer 110 stacked on each of the plurality of anodes 111 and a bank unit 112 disposed between the functional layers 110 to partition the functional layers 110. . A cathode 12 is disposed on the functional layer 110. The organic EL element 10 which is a light emitting element includes an anode 111, a cathode 12, a functional layer 110, and the like.

  The anode 111 is made of ITO, and is formed by patterning into a substantially rectangular shape in plan view. The thickness of the anode 111 is preferably in the range of 50 nm to 200 nm, particularly about 150 nm.

As shown in FIG. 3, the bank unit 112 includes an inorganic bank layer 112 a (first bank layer) positioned on the substrate 2 side and an organic bank layer 112 b (second bank layer) positioned away from the substrate 2. Configured. The inorganic bank layer 112a is made of an inorganic material such as SiO ₂ or TiO ₂ , for example. The organic bank layer 112b is formed of a resist having heat resistance and solvent resistance such as acrylic resin and polyimide resin.

  The functional layer 110 includes a hole injection / transport layer 110a stacked on the anode 111, and an organic EL layer (light emitting layer) 110b formed adjacent to the hole injection / transport layer 110a. .

  The hole injection / transport layer 110a has a function of injecting holes into the organic EL layer 110b and a function of transporting holes inside the hole injection / transport layer 110a. By providing such a hole injection / transport layer 110a between the anode 111 and the organic EL layer 110b, device characteristics such as light emission efficiency and lifetime of the organic EL layer 110b are improved. Further, in the organic EL layer 110b, holes injected from the hole injection / transport layer 110a and electrons injected from the cathode 12 are recombined in the organic EL layer, and light emission is obtained.

The organic EL layer 110b emits light from the red organic EL layer 110b ₁ that emits red (R), the green organic EL layer 110b ₂ that emits green (G), and the blue organic EL layer 110b ₃ that emits blue (B). The organic EL layers 110b _{1 to} 110b ₂ are arranged in a predetermined arrangement (for example, a stripe shape). In this embodiment, the organic EL layer 110b is composed of a polymer light emitting material (polymer organic EL material). For example, the organic EL layer 110b is composed of a low molecular light emitting material (low molecular organic EL material). It is good to do.

  On the other hand, the cathode (counter electrode) 12 is formed by laminating two layers having different work functions, and is composed mainly of a calcium layer (first cathode) 12a composed mainly of calcium and aluminum. And an aluminum layer (second cathode) 12b. Such a cathode 12 plays a role of passing a current through the functional layer 110 in a pair with the anode 111. As a material constituting the first cathode, for example, cesium can be used in addition to calcium, and as a material constituting the second cathode, for example, MgAg (magnesium and silver alloy) other than aluminum can be used. Indium tin oxide (ITO) or the like can be used.

  The calcium layer 12a having a relatively small work function is stacked on the functional layer 110, and is formed in a predetermined pattern for each pixel region A (R, G, B). On the other hand, the aluminum layer 12b having a relatively large work function is formed on the entire surface of the substrate 2 across the pixel regions A (R, G, B). The aluminum layer 12b has a function of reflecting light emitted from the functional layer 110 to the substrate 2 side.

  Here, in the organic EL device 1 according to the present embodiment, the outer edge 12g of the calcium layer 12a in the cathode 12 is positioned inside the outer edge 110g of the organic EL layer 110b. That is, the calcium layer 12a and the organic EL layer 110b are disposed relative to each other so that the formation region of the calcium layer 12a is located in the plan view of the formation region of the organic EL layer 110b. 12a has a configuration in which the planar view is not superimposed.

  Therefore, in the organic EL layer 110b formed in the pixel region A (R, G, B in FIG. 3), for example, due to the affinity with the bank 112 and the difference in the surface state on the anode 111 during manufacturing, Even when the film thickness varies (difference) between the central portion and the outer peripheral portion of the pixel region A, the calcium layer 12a is formed in the peripheral region of the organic EL layer 110b (the outer peripheral portion of the pixel region A). In this case, no current flows through the peripheral area, and no light emission occurs. As a result, it is supposed that uniform light emission can be obtained without causing a luminance variation in the pixel region A (R, G, B) due to a variation in film thickness in the organic EL layer 110b.

  In the organic EL device 1 of the present embodiment, the hole injecting / transporting layer 110a and the organic EL layer 110b are prepared by using a liquid composition obtained by dissolving or dispersing an organic material constituting them in a solvent by an inkjet method (liquid A film is formed by selectively discharging by a droplet discharge method and then drying the liquid composition. Prior to the discharge, the surface of the bank 112 is subjected to a liquid repellent treatment, and the anode 111 is subjected to a lyophilic treatment. In the hole injection / transport layer 110a and the organic EL layer 110b, variations in film thickness as described above can occur.

  Next, a method for manufacturing the organic EL device 1 will be described with reference to FIG. On the substrate 2, the circuit element portion 14 including the thin film transistor, the bank portion 112 (the organic bank layer 112a and the inorganic bank layer 112b), and the anode 111, which are respectively shown in FIG. 3, are already formed. And

  The manufacturing method of this example includes (1) a hole injection / transport layer forming step, (2) an organic EL layer forming step, (3) a cathode forming step, and (4) a sealing step. In addition, the manufacturing method demonstrated here is an example, Comprising: Another process may be added as needed, and a part of said process may be removed. The (1) hole injection / transport layer forming step and (2) organic EL layer forming step were performed using a liquid discharge method (inkjet method) using a droplet discharge device.

(1) Hole Injection / Transport Layer Formation Step As shown in FIG. 8A, the hole injection / transport layer 110a is formed on the substrate 2 on which the anode 111 is formed. In the hole injection / transport layer forming step, for example, a composition including a hole injection / transport layer forming material is discharged onto the anode 111 by using a liquid discharge method. Thereafter, drying treatment and heat treatment are performed to form the hole injection / transport layer 110 a on the anode 111. The subsequent steps including the hole injection / transport layer forming step are preferably performed in an inert gas atmosphere such as a nitrogen atmosphere or an argon atmosphere.

  As a procedure for forming a hole injection / transport layer by a liquid discharge method, a discharge head (not shown) for discharging a liquid is filled with a composition ink containing a material for the hole injection / transport layer, and then the discharge head is used. The discharge nozzle is opposed to the anode 111 located in the opening of the bank portion 112, and ink droplets with controlled liquid amount per droplet are discharged from the discharge nozzle while relatively moving the discharge head and the substrate 2. . Thereafter, the ejected ink droplets are dried to evaporate the polar solvent (liquid material) contained in the composition ink, thereby forming the hole injection / transport layer.

  As the composition used here, for example, a composition obtained by dissolving a mixture of a polythiophene derivative such as polyethylenedioxythiophene (PEDOT) and polystyrenesulfonic acid (PSS) in a polar solvent can be used. Examples of the polar solvent include isopropyl alcohol (IPA), normal butanol, γ-butyrolactone, N-methylpyrrolidone (NMP), 1,3-dimethyl-2-imidazolidinone (DMI) and its derivatives, carbitol acetate And glycol ethers such as butyl carbitol acetate. More specifically, the composition of the PEDOT: PSS mixture (PEDOT / PSS = 1: 20): 12.52 wt%, PSS: 1.44 wt%, IPA: 10 wt%, NMP: 27.48 A weight%, DMI: 50 weight% can be illustrated. The viscosity of the composition is preferably about 2 to 20 Ps, particularly about 4 to 15 cPs.

(2) Organic EL Layer Formation Step Next, as shown in FIG. 8B, the organic EL layer 110b is formed on the hole injection / transport layer 110a. In this embodiment, the blue organic EL layer 110b ₃ is formed, and then the red organic EL layer 110b ₁ and the green organic EL layer 110b ₂ are sequentially formed. Here, a composition ink containing an organic EL layer material is ejected onto the hole injection / transport layer 110a by a liquid ejection method, and then dried and heat-treated, whereby each color is formed in the opening formed in the bank 112. The organic EL layer 110b is formed.

  In the organic EL layer forming step, in order to prevent re-dissolution of the hole injection / transport layer 110a, it is insoluble in the hole injection / transport layer 110a as a solvent for the composition ink used in forming the organic EL layer. A nonpolar solvent is used. In this case, in order to improve the wettability of the surface of the hole injection / transport layer 110a with respect to the nonpolar solvent, it is preferable to perform a surface modification step before forming the organic EL layer. The surface modification step is performed, for example, by applying the same solvent as the nonpolar solvent or a similar solvent on the hole injection / transport layer 110a by a liquid discharge method, a spin coating method, a dip method, or the like and then drying. Examples of the surface modifying solvent used here are cyclohexylbenzene, dihydrobenzofuran, trimethylbenzene, tetramethylbenzene and the like as the nonpolar solvent of the composition ink. Examples of the solvent are toluene, xylene and the like.

As a procedure for forming an organic EL layer by a liquid discharge method, first, a blue organic EL layer is formed. In forming the blue organic EL layer, a discharge head (not shown) is filled with a composition ink containing a material for forming the blue organic EL layer, and the discharge nozzle of the discharge head is placed in the opening of the bank unit 112. While facing the blue (B) hole injecting / transporting layer 110a positioned and moving the ejection head and the substrate 2 relative to each other, ink droplets whose liquid amount per droplet is controlled are ejected from the ejection nozzle. The ejected ink droplet spreads on the hole injection / transport layer 110a and fills the opening of the bank 112. Subsequently, by drying the discharged ink droplets, the nonpolar solvent contained in the composition ink is evaporated, and the blue organic EL layer 110b ₃ is formed.

As the light emitting material for forming a blue organic EL layer 110b _3, it can be used, for example distyryl biphenyl and its derivatives, coumarin and its derivatives, those made of an organic EL material such as tetraphenylbutadiene and its derivatives. On the other hand, as the nonpolar solvent, those insoluble in the hole injection / transport layer are preferable. For example, cyclohexylbenzene, dihydrobenzofuran, trimethylbenzene, tetramethylbenzene, and the like can be used.

Subsequently, on the hole injection / transport layer 110a for red (R) and green (G), to form a red organic EL layer 110b ₁ and green organic EL layer 110b _2, respectively. This red and green organic EL layer forming step is performed in the same procedure as the blue organic EL layer forming step described above. That is, a composition ink containing an organic EL layer material is ejected onto the hole injection / transport layer 110a by a liquid ejection method, followed by drying and heat treatment, and an organic EL layer is formed in the opening formed in the bank 112. Form. As, as the light emitting material for example can be used one made of an organic EL material, such as rhodamine and its derivatives, form a green organic EL layer 110b ₂ emitting material for forming the red organic EL layer 110b _1, e.g. What consists of organic EL materials, such as a quinacridone and its derivative (s), can be used.

(3) Cathode formation process Next, the cathode 12 which makes a pair with the anode 111 is formed. Here, the aluminum layer 12a shown in FIG. 8 (d) is formed after the calcium layer 12a is formed as shown in FIG. 8 (c).

  In the step of forming the calcium layer 12a, as shown in FIG. 8C, on each color organic EL layer 110b, by a vapor deposition method, a sputtering method, a CVD method, etc. through a mask having a predetermined pattern opening, The calcium layer 12a is formed into a pattern. Specifically, the calcium layer 12a is arranged so as to overlap in a plan view so that the outer edge 12g of the calcium layer 12a is positioned inside the outer edge 110g of the organic EL layer 110b, that is, inside the formation region of the organic EL layer 110b. Thus, the calcium layer 12a is formed. Note that the calcium layer 12a may be formed by patterning by a photolithography technique after the calcium layer is formed over the entire pixel region.

  Further, in the step of forming the aluminum layer 12b, as shown in FIG. 8D, aluminum is deposited on the entire surface of the substrate 2 including each color organic EL layer 110b and the bank portion 112 by a vapor deposition method, a sputtering method, or a CVD method. For example, the film is formed.

(4) Sealing step Finally, the substrate 2 on which the organic EL element (light emitting element) is formed and the sealing substrate 3b (see FIG. 1) are sealed with a sealing resin. For example, a sealing resin made of a thermosetting resin or an ultraviolet curable resin is applied to the peripheral portion of the substrate 2, and the sealing substrate 3b is disposed on the sealing resin.
The sealing step is preferably performed in an inert gas atmosphere such as nitrogen, argon, or helium. If it is carried out in the air, when a defect such as a pinhole has occurred in the cathode 12, water or oxygen may enter the cathode 12 from the defective portion and the cathode 12 may be oxidized, which is not preferable.

  Thereafter, the cathode 12 is connected to the wiring of the substrate 2, and the wiring of the circuit element unit 14 (see FIG. 1) is connected to a driving IC (driving circuit) provided on or outside the substrate 2. The organic EL device 1 is completed.

(Second Embodiment)
Next, a second embodiment of the organic EL device of the present invention will be described with reference to FIG. In addition, description is abbreviate | omitted as what has the structure similar to 1st Embodiment except the component demonstrated by this 2nd Embodiment.

In the organic EL device 1a of the second embodiment, with respect to the pixel region B includes a blue organic EL layer 110b _3, the electron injection layer 12c is selectively provided. The electron injection layer 12 c is made of lithium fluoride and has a function of promoting electron injection from the cathode 12 to the functional layer 110. In the present embodiment, the electron injection layer 12c is also disposed so that the outer edge 12h of the electron injection layer 12c is located on the inner side of the outer edge 110g of the organic EL layer 110b, similarly to the calcium layer 12a. That is, the electron injection layer 12c is disposed so as to overlap in a plan view inside the region where the organic EL layer 110b is formed.

  Also in the organic EL device 1a of the second embodiment, the outer edge 12g of the calcium layer 12a is located inside the outer edge 110g of the organic EL layer 110b, and the outer edge 12h of the electron injection layer is also organic. It is located inside the outer edge 110g of the EL layer 110b. Accordingly, in the organic EL layer 110b formed in the pixel region A (R, G, B), for example, due to the affinity with the bank unit 112 and the difference in the surface state on the anode 111 during manufacturing, the pixel region A Even when the film thickness varies (difference) between the central portion and the outer peripheral portion, the calcium layer 12a and the electron injection layer 12c are formed in the peripheral region of the organic EL layer 110b (the outer peripheral portion of the pixel region A). By not being carried out, the said peripheral area | region will not be contributed to light emission. As a result, it is supposed that uniform light emission can be obtained without causing variations in luminance due to variations in film thickness in the organic EL layer 110b. Note that such an effect of uniform light emission can also be obtained in the organic EL device 1b in which the electron injection layer 12c is formed in the entire pixel region (in the region surrounded by the bank 112) as shown in FIG. Can do. Further, the electron injection layer 12c may be formed not only in the blue pixel region B but also in the green and red pixel regions G and R.

(Third embodiment)
Next, a third embodiment of the organic EL device of the present invention will be described with reference to FIG. In addition, description is abbreviate | omitted as what has the structure similar to 1st Embodiment except the component demonstrated by this 3rd Embodiment.

  In the organic EL device 1c of the third embodiment, an electron injection shielding layer 13 that shields electron injection is formed between the functional layer 110 and the cathode 12. Specifically, it is formed so as to surround the outer periphery of the calcium layer 12a, that is, selectively formed at a position overlapping the outer peripheral portion of the organic EL layer 110b in plan view. Accordingly, the electron injection shielding layer 13 is configured in a ring shape having an opening at its center in the region surrounded by the bank 112 so that electron injection is performed only in the opening. . The electron injection shielding layer 13 is made of a material having a function of hindering electron injection from the cathode 12 to the functional layer 110, such as a silicon oxide film.

  Also in the organic EL device 1c according to the third embodiment, the outer edge 12g of the calcium layer 12a is located inside the outer edge 110g of the organic EL layer 110b, and the electron injection shielding layer 13 is the organic EL layer 110b. It is selectively formed at a position overlapping the outer peripheral portion in plan view. Accordingly, in the organic EL layer 110b formed in the pixel region A (R, G, B), for example, due to the affinity with the bank unit 112 and the difference in the surface state on the anode 111 during manufacturing, the pixel region A Even in the case where the film thickness varies (difference) between the central portion and the outer peripheral portion, the calcium layer 12a is not formed in the peripheral region of the organic EL layer 110b (the outer peripheral portion of the pixel region A). In addition, since the electron injection shielding layer 13 is formed, the peripheral region does not contribute to light emission. As a result, it is supposed that uniform light emission can be obtained without causing variations in luminance due to variations in film thickness in the organic EL layer 110b.

  In addition, in the type (top emission type) in which light emitted from the functional layer 110 is extracted from a side different from the substrate 2 as in the organic EL device 1d shown in FIG. 7, the light-shielding electron injection shielding layer 13a is used. Can do. In this case, even if light emission occurs in the outer peripheral portion of the organic EL layer 110b, the light is blocked by the electron injection blocking layer 13a, so that light can be prevented from passing to the cathode 12e side. As a result, the pixel region A ( R, G, and B) can be further prevented from generating luminance variations. In the organic EL device 1d, a light-reflective anode 111b made of aluminum or the like is used as a pixel electrode formed on the substrate 2, and a light-transmissive cathode 12e made of ITO (indium tin oxide) is used as a counter electrode. Can be used.

  Furthermore, when such electron injection shielding layers 13 and 13a are formed, the calcium layer 12a can be formed across the pixel regions A (R, G, and B). That is, if the electron injection shielding layers 13 and 13a are interposed between the organic EL layer 110b and the calcium layer 12a, the calcium layer 12a is located at a position overlapping the outer peripheral portion of the organic EL layer 110b in plan view. Even if formed, electron injection into the outer peripheral portion of the organic EL layer 110b can be blocked, and light emission at the outer peripheral portion can be prevented or suppressed.

(Fourth embodiment)
9 and 10 show an embodiment of the electronic apparatus of the present invention. The electronic apparatus of this example includes the above-described organic EL device as display means.
FIG. 9 is a perspective view showing an example of a mobile phone. Reference numeral 1000 denotes a mobile phone main body, and reference numeral 1001 denotes a display unit using the organic EL device. As described above, an electronic apparatus including the organic EL device according to the electro-optical device of the present invention as a display unit can obtain good light emission characteristics and has extremely high reliability.

  FIG. 10 is a perspective view illustrating an example of a video monitor. The video monitor 1200 includes a display unit 1201 including an organic EL device, a housing 1202, a speaker 1203, and the like. According to the video monitor 1200, good light emission characteristics can be obtained, and the reliability is extremely high.

  The organic EL device of each of the above embodiments is not limited to the mobile phone and the video monitor as described above, but an electronic book, a personal computer, a digital still camera, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, It can be used suitably as an image display means for devices such as pagers, electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, touch panels, etc. Is obtained.

FIG. 3 is a perspective view showing the organic EL device according to the first embodiment with a part cut away. FIG. 2 is an equivalent circuit diagram of the organic EL device in FIG. 1. The partial cross section schematic diagram of the organic electroluminescent apparatus of FIG. The partial cross section schematic diagram of the organic electroluminescent apparatus of 2nd Embodiment. The partial cross-section schematic diagram which shows the modification of the organic electroluminescent apparatus of 2nd Embodiment. The partial cross section schematic diagram of the organic electroluminescent apparatus of 3rd Embodiment. The partial cross section schematic diagram which shows the modification of the organic electroluminescent apparatus of 3rd Embodiment. The partial cross section schematic diagram which shows an example of the manufacturing process of the organic electroluminescent apparatus of 1st Embodiment. The perspective view which shows one Embodiment of an electronic device. The perspective view which shows one Embodiment of an electronic device.

Explanation of symbols

  2 ... Glass substrate (substrate), 12 ... cathode, 12a ... calcium layer (first cathode), 12b ... aluminum layer (second cathode), 110b ... organic EL layer, 111 ... anode, 112 ... bank part (partition wall part) , A (R, G, B) ... pixel region

Claims (12)

A partition wall that partitions and forms a plurality of pixel regions is formed on the substrate.
The pixel region is formed by laminating at least an anode, an organic EL layer, and a cathode,
While the organic EL layer is formed in a region surrounded by the partition wall,
The cathode has a laminated structure in which a first cathode having a relatively small work function and a second cathode having a relatively large work function are laminated in this order from the organic EL layer side. Among these, at least the first cathode is formed such that the outer edge of the first cathode is located inside the outer edge of the organic EL layer.   The organic EL device according to claim 1, wherein the second cathode is formed across the pixel regions.   The organic EL device according to claim 1, wherein the anode is configured as a pixel electrode patterned for each pixel region on the substrate.   The organic EL device according to any one of claims 1 to 3, wherein the first cathode is made of calcium, and the second cathode is made of aluminum.   5. The organic EL device according to claim 1, wherein an electron injection layer made of lithium fluoride is formed between the organic EL layer and the first cathode. 6.   The organic EL device according to claim 5, wherein the electron injection layer is formed such that an outer edge of the electron injection layer is positioned inside an outer edge of the organic EL layer.   An electron injection shielding layer for shielding electron injection is formed between the organic EL layer and the cathode, and the electron injection shielding layer is selectively disposed at a position overlapping the outer peripheral portion of the organic EL layer in plan view. The organic EL device according to claim 1, wherein the organic EL device is formed.   The said cathode has translucency, the light emitted by the said organic EL layer is inject | emitted from the said cathode side, The said electron injection shielding layer has light-shielding property, It is characterized by the above-mentioned. 8. The organic EL device according to 7.   The organic EL layer is formed by applying a liquid material in which an organic material constituting the organic EL layer is dissolved or dispersed in a solvent to a region surrounded by the partition wall. The organic EL device according to claim 1.   The organic EL device according to claim 9, wherein the organic EL layer is formed by a droplet discharge method. A partition wall forming step for forming a partition wall for partitioning a plurality of pixel regions on the substrate;
An anode forming step of forming an anode on the substrate;
An organic EL layer forming step of forming an organic EL layer on the anode;
A cathode forming step of forming a cathode on the organic EL layer,
In the organic EL layer forming step, a liquid material obtained by dissolving or dispersing an organic material constituting the organic EL layer in a solvent is applied to a region surrounded by the partition wall, and the applied liquid material is dried. While including a process,
The cathode forming step is a step of patterning a first cathode having a relatively small work function on the organic EL layer so that an outer edge of the first cathode is positioned inside an outer edge of the organic EL layer. And forming a second cathode having a relatively high work function on the first cathode. A method for manufacturing an organic EL device, comprising:   An electronic apparatus comprising the organic EL device according to claim 1.

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