JP4265230B2 - ELECTRO-OPTICAL DISPLAY DEVICE, ITS MANUFACTURING METHOD, AND ELECTRONIC DEVICE - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electro-optic display device in which a pixel interval wall made of an organic material is formed between light emitting pixels, a manufacturing method thereof, and an electronic apparatus.
[0002]
[Prior art and problems to be solved by the invention]
In recent years, in an electronic device such as a notebook computer, a mobile phone, and an electronic notebook, an organic EL display device or the like provided with an organic electroluminescence (hereinafter referred to as organic EL) element (light emitting element) corresponding to a pixel as a means for displaying information. Electro-optical display devices have been proposed. In general, in an organic EL element, an organic functional layer including a light emitting layer (organic EL layer) is disposed between a pair of opposed electrodes, and light emitted from adjacent pixels is interposed between the organic EL elements. The pixel spacing walls (bank layers) made of an organic material are arranged in contact with the organic functional layer so that the interference does not occur.
[0003]
By the way, the pixel spacing wall is generally formed by applying a photosensitive material (organic material) having heat resistance and solvent resistance such as acrylic resin and polyimide resin on the substrate, and forming an organic EL element by photolithography technology. The pixel region is formed by forming an opening in the pixel region. Such a process for forming the pixel interval wall includes a process using moisture, that is, a so-called wet process (for example, a wet etching process or a process of rinsing with acetone after the pixel interval wall is etched).
[0004]
[Patent Document 1]
International Publication No. 98/12789 Pamphlet
[0005]
Since the pixel spacing walls are made of an organic material such as acrylic resin or polyimide resin, a minute cavity is formed in the interior, and moisture enters the cavities of the pixel spacing walls by the wet process described above. The The moisture that has entered into the cavity of the pixel spacing wall in this manner gradually goes out of the pixel spacing wall due to long-term storage or high-temperature storage, thereby degrading the light emitting layer of the completed organic EL display device. This causes a decrease in luminance of the EL display device and a so-called dark spot (a region that does not emit light). Moreover, since the cavity is formed in the pixel interval wall as described above, the moisture permeability is high. For this reason, the water | moisture content which came out from the certain pixel interval wall passes through the other pixel interval wall, degrades another light emitting layer, and the problem that the brightness | luminance fall of an organic EL display apparatus and a dark spot spread also arises.
[0006]
The present invention has been made in view of the above-described problems, and an electro-optic display device that prevents a decrease in luminance and a dark spot due to moisture coming out from a pixel interval wall due to long-term storage or high-temperature storage, and a manufacturing method thereof, and An object is to provide electronic equipment.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an electro-optical display device according to the present invention is an electro-optical display device in which a pixel interval wall made of an organic material is formed between light emitting pixels, and the pixel interval wall includes the organic optical display device. It is characterized by containing a filler made of a material having a lower molecular weight than the material.
[0008]
According to the electro-optic display device having such a configuration, since the pixel interval wall contains a filler made of a material having a lower molecular weight than the organic material constituting the pixel interval wall (hereinafter referred to as a filler), the pixel Filler is filled in the cavity of the spacing wall. As described above, since the filler is filled in the cavity of the pixel interval wall, moisture does not enter the pixel interval wall by the above-described wet process, so that no moisture is contained in the pixel interval wall. As a result, since the water does not come out from the pixel interval wall even when the electro-optical display device in which such a pixel interval wall is formed is stored for a long period of time or at a high temperature, the luminance caused by the moisture coming out from the pixel interval wall It is possible to prevent the occurrence of lowering and dark spots.
[0009]
The filler is preferably an inorganic material having a lower molecular weight than the organic material, and more preferably a dehydrating material. By adopting a dehydrating material as the filler, even if some moisture is contained in the pixel interval wall, this moisture can be prevented from coming out of the pixel interval wall. In addition, since the moisture permeability of the pixel interval wall is reduced by filling the filler, even if moisture comes out of a certain pixel interval wall, the moisture does not pass through other pixel interval walls. Other electro-optical elements are not deteriorated, and the influence on the electro-optical display device can be minimized.
[0010]
Moreover, it is preferable that a filler is the predetermined | prescribed color which suppresses reflection of the light in the pixel space | interval wall in which self was contained. The filler is more preferably black, such as titanium black. By adopting the black filler, the color of the pixel interval wall becomes black, so that reflection of light on the pixel interval wall can be suppressed, and as a result, the visibility of the electro-optical display device is improved.
[0011]
Further, the filler is preferably contained in an amount of 10% to 30% with respect to the pixel interval wall. For example, when the filler content is 10% or less with respect to the pixel interval wall, the filler cannot sufficiently fill the cavity of the pixel interval wall. On the other hand, when the filler content is 30% or more, the pixel interval wall becomes brittle, and the durability of the electro-optical display device is lowered.
[0012]
The method for manufacturing an electro-optical display device according to the present invention is characterized in that the pixel interval walls are formed by a dry etching technique. By adopting this manufacturing method, the pixel interval walls are formed without performing wet etching, so that the possibility that the pixel interval walls contain moisture can be reduced. As a result, it is possible to provide an electro-optic display device that more reliably prevents a decrease in luminance and a dark spot due to moisture coming from the pixel interval wall.
[0013]
According to another aspect of the invention, an electronic apparatus includes the above-described electro-optic display device. Therefore, it is possible to provide an electronic apparatus equipped with an electro-optical display device that prevents a decrease in luminance and dark spots due to moisture from the pixel interval walls.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electro-optical display device, a manufacturing method thereof, and an electronic apparatus according to an embodiment of the invention will be described with reference to the drawings. In each of the drawings 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.
[0015]
FIG. 1 is a schematic plan view showing a wiring structure of an organic EL display device which is an embodiment of the electro-optical display device. As shown in FIG. 1, the organic EL display device 1 includes a plurality of scanning lines 101, a plurality of signal lines 102 extending in a direction intersecting the scanning lines 101, and a plurality of power supplies extending in parallel to the signal lines 102. Lines 103 are respectively wired. An area partitioned by the scanning line 101 and the signal line 102 is configured as a pixel area.
[0016]
Connected to the signal line 102 is a data side driving circuit 104 including a shift register, a level shifter, a video line, and an analog switch. Further, a scanning side driving circuit 105 including a shift register and a level shifter is connected to the scanning line 101.
[0017]
In each pixel region, a switching thin film transistor 112 to which a scanning signal is supplied to the gate electrode via the scanning line 101 and a pixel signal shared from the signal line 102 via the switching thin film transistor 112 are held. A capacitor cap, a driving thin film transistor 123 to which a pixel signal held by the holding capacitor cap is supplied to the gate electrode, and the power source when electrically connected to the power source line 103 via the driving thin film transistor 123 A pixel electrode 111 into which a driving current flows from the line 103 and an organic functional layer 110 sandwiched between the pixel electrode 111 and the cathode 12 are provided. The pixel electrode 111, the cathode 12, and the organic functional layer 110 constitute a light emitting portion A (light emitting pixel), and the organic EL display device 1 includes a plurality of the light emitting portions A in a matrix.
[0018]
According to such a configuration, when the scanning line 101 is driven and the switching thin film transistor 112 is turned on, the potential of the signal line 102 at that time is held in the holding capacitor cap, and according to the state of the holding capacitor cap. The on / off state of the driving thin film transistor 123 is determined. Then, a current flows from the power supply line 103 to the pixel electrode 111 through the channel of the driving thin film transistor 123, and further a current flows to the cathode 12 through the organic functional layer 110. The organic functional layer 110 emits light according to the amount of current flowing through it.
[0019]
FIG. 2 is a schematic plan view of the organic EL display device 1, and FIG. 3 is a schematic cross-sectional view of FIG. 2 taken along the line II ′. As shown in FIG. 3, in the organic EL display device 1 of the present embodiment, a circuit element unit 14 and a display element (organic EL element) unit 10 are sequentially stacked on a substrate 2, and the substrate surface on which the stacked body is formed. Has a structure sealed by the sealing portion 3. The display element unit 10 includes a light emitting element unit 11 including an organic functional layer 110 and a cathode 12 formed on the light emitting element unit 11. The pixel electrode 111 has translucency, and the organic EL display device 1 is configured as a so-called bottom emission type display device in which display light emitted from the light emitting layer 110b is emitted from the substrate 2 side. .
[0020]
Examples of the light-transmitting substrate 2 include glass, quartz, and resin (plastic and plastic film), and an inexpensive soda glass substrate is particularly preferably used. As shown in FIG. 2, the substrate 2 is partitioned into a display region 2 a located at the center and a non-display region 2 b surrounding the display region 2 a located at the periphery of the substrate 2. The display area 2a is an area formed by the light emitting portions A arranged in a matrix, and a non-display area 2b is formed outside the display area. In the non-display area 2b, a dummy display area 2d adjacent to the display area 2a is formed.
[0021]
As shown in FIG. 3, the circuit element unit 14 includes the above-described scanning line, signal line, storage capacitor, switching thin film transistor, driving thin film transistor 123, and the like, and is arranged in the display region 2a. The light emitting unit A is driven. One end of the cathode 12 is connected to the cathode wiring 120 formed on the substrate 2 from the light emitting element portion 11, and one end of the wiring is connected to the wiring 5 a on the flexible substrate 5. The wiring 5a is connected to a driving IC 6 (driving circuit) provided on the flexible substrate 5 (see FIG. 2).
[0022]
Further, the above-described power supply lines 103 (103R, 103G, 103B) are wired in the non-display area 2b of the circuit element unit 14. Further, the above-described scanning side drive circuits 105 and 105 are arranged on both sides of the display area 2a in FIG. The scanning side drive circuits 105 and 105 are provided in the circuit element portion 14 below the dummy region 2d. Further, in the circuit element section 14, a drive circuit control signal line 105a and a drive circuit power supply line 105b connected to the scanning side drive circuits 105 and 105 are provided. Further, an inspection circuit 106 is arranged above the display area 2a in FIG. The inspection circuit 106 can inspect the quality and defects of the display device during manufacturing or at the time of shipment.
[0023]
The sealing unit 3 includes a sealing resin 603 applied to the substrate 2 and a sealing can (sealing member) 604. The sealing resin 603 is an adhesive that adheres the substrate 2 and the sealing can 604, and is applied annularly around the substrate 2 by, for example, a microdispenser. The sealing resin 603 is made of a thermosetting resin, an ultraviolet curable resin, or the like, and is particularly preferably made of an epoxy resin that is a kind of thermosetting resin. Further, the sealing resin 603 is made of a material that hardly allows oxygen or moisture to pass therethrough, preventing water or oxygen from entering the sealing can 604 from between the substrate 2 and the sealing can 604, and the cathode 12. Alternatively, oxidation of the light emitting layer 110b formed in the light emitting element portion 11 is prevented.
[0024]
The sealing can 604 is provided with a recess 604 a for accommodating the display element 10 inside thereof, and is bonded to the substrate 2 via a sealing resin 603. Note that, on the inner surface side of the sealing can 604, a getter material that absorbs or removes oxygen and moisture can be provided in a region corresponding to the non-display region 2b as necessary. Examples of the getter material include alkali metals such as Li, Na, Rb, and Cs, alkaline earth metals such as Be, Mg, Ca, Sr, and Ba, oxides of alkaline earth metals, alkali metals, and alkaline earths. A metal hydroxide or the like can be preferably used. Alkaline earth metal oxides act as a dehydrating agent by reacting with water and changing to hydroxides. Alkali metal or alkaline earth metal reacts with oxygen to change into hydroxide and reacts with water to change into oxide, and thus acts not only as a dehydrating material but also as a deoxidizing material. Thereby, the oxidation of the light emission part A can be prevented and the reliability of the apparatus can be enhanced.
[0025]
In FIG. 4, the figure which expanded the cross-section of the display area 2a in this organic electroluminescence display 1 is shown. The organic EL display device 1 includes a light emitting element portion 11 in which a circuit element portion 14 in which a circuit such as a TFT is formed on a substrate 2, a pixel electrode 111, and an organic functional layer 110 including a light emitting layer 110b are formed. And the cathode 12 are sequentially laminated.
[0026]
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. Further, a portion where P is not introduced is a channel region 141c.
[0027]
In the circuit element portion 14, a gate insulating film 142 that covers the base protective film 2c and the semiconductor film 141 is formed. A gate electrode 143 (scanning line 101) made of Al, Mo, Ta, Ti, W, or the like is formed on the gate insulating film 142 at a position corresponding to the channel region 141c of the semiconductor film 141. The semiconductor film 141, the gate insulating film 142, and the gate electrode 143 constitute a thin film transistor 123. In the thin film transistor 123, since the semiconductor film 141 uses polysilicon, display with high luminance and high definition can be realized.
[0028]
Further, a transparent first interlayer insulating film 144a and a second interlayer insulating film 144b are formed on the gate electrode 143 and the gate insulating film 142, and the first and second interlayer insulating films 144a and 144b are insulated. Contact holes 145 and 146 are formed through the films 144a and 144b and connected to the source and drain regions 141a and 141b of the semiconductor film 141, respectively. The contact hole 145 is connected to the pixel electrode, and the pixel electrode 111 and the semiconductor source region 141 a are electrically connected through the contact hole 145. Further, the contact hole 146 is connected to the power supply line 103, and a pixel signal is supplied from the power supply line 103 through the contact hole 146.
[0029]
The driving circuit is configured as described above. The circuit element unit 14 is also formed with the storage capacitor cap and the switching thin film transistor 142 described above, but these are not shown in FIG.
[0030]
The pixel electrodes 111 are formed by patterning in a substantially rectangular shape in plan view on the second interlayer insulating film 144b, and a plurality of pixel electrodes 111 are arranged in a matrix in the display region 2a. For the pixel electrode 111, a light-transmitting conductive material made of a metal oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO) is used.
[0031]
The light emitting element unit 11 includes an organic functional layer 110 stacked on each of the plurality of pixel electrodes 111, and a bank layer 112 (provided between each pixel electrode 111 and the organic functional layer 110) that partitions each organic functional layer 110. The pixel interval wall) is the main component. The cathode 12 is disposed on the organic functional layer 110, and the pixel electrode 111, the organic functional layer 110, and the cathode 12 constitute a light emitting portion A.
[0032]
The bank layer 112 is made of an organic material having excellent heat resistance and solvent resistance, such as acrylic resin and polyimide resin, and has an opening 112d corresponding to the position where the pixel electrode 111 is formed. The bank layer 112 contains a filler 150 (hereinafter referred to as a filler) made of a material having a lower molecular weight than the organic material constituting the bank layer 112. For this reason, the filler 150 is filled in the cavity formed inside the bank layer 112. Therefore, it is possible to reduce the moisture permeability of the bank layer 112 and prevent the bank layer 112 from containing moisture in the process of forming the bank layer 112. In the unlikely event that moisture comes out of a certain bank layer 112, the moisture does not pass through the other bank layer 112, so the other light emitting layer 110 b is not deteriorated, and the present organic EL display device 1 is brought into contact. Can be minimized.
[0033]
In addition, as the filler 150, it is preferable to use an inorganic material having low moisture permeability as compared with an organic material, and specifically, silica gel, titanium oxide, or the like can be used. It is more preferable to use a dehydrating material as the filler 150. By using a dehydrating material as the filler 150, even if the bank layer 112 contains a small amount of moisture in the formation process of the bank layer 112, the dehydrating material retains moisture, and the moisture remains in the bank layer 112. It is possible to prevent going outside. Examples of the filler 150 having such a dehydrating effect include calcium oxide. The filler 150 preferably has a color that suppresses reflection of light in the bank layer 112 such as titanium black. By adopting the black filler, the color of the bank layer 112 becomes black, so that reflection of light in the bank layer 112 can be suppressed.
[0034]
Such a filler 150 is preferably contained in an amount of 10% to 30% with respect to the bank layer 112. For example, if the filler content in the bank layer 112 is 10% or less, the filler 150 cannot sufficiently fill the cavities of the bank layer 112. On the other hand, when the content of the filler 150 is 30% or more, the bank layer 112 becomes brittle, and the durability of the organic EL display device 1 is lowered.
[0035]
In each region partitioned by the bank layer 112, the electrode surface 111a of the pixel electrode 111 is lyophilic with plasma processing using oxygen as a processing gas and exhibits lyophilicity. On the other hand, the wall surface of the opening 112d and the upper surface 112f of the bank layer 112 are fluorinated (liquid repellent) by plasma treatment using tetrafluoromethane as a processing gas, and exhibit liquid repellency.
[0036]
The organic functional layer 110 includes a hole injection / transport layer 110a stacked on the pixel electrode 111, a light emitting layer 110b formed adjacent to the hole injection / transport layer 110a, and adjacent to the light emitting layer 110b. And an electron injection / transport layer 110c formed as described above. The hole injection / transport layer 110a has a function of injecting holes into the light emitting layer 110b and a function of transporting holes inside the hole injection / transport layer 110a. As the hole injection / transport layer forming material, for example, a mixture of a polythiophene derivative such as polyethylenedioxythiophene and polystyrenesulfonic acid can be used. The electron injection / transport layer 110c has a function of injecting electrons into the light emitting layer 110b and a function of transporting electrons inside the electron injection / transport layer 110c. As the electron injection / transport layer 110c, for example, lithium quinolinol (Liq), lithium fluoride (LiF), bathophenesium, or the like can be preferably used. A metal having a work function of 4 eV or less, such as Mg, Ca, Ba, Sr, Li, Na, Rb, Cs, Yb, Sm, or the like can also be used.
[0037]
By providing such a hole injection / transport layer 110a and an electron injection / transport layer 110c between the pixel electrode 111 and the light emitting layer 110b and between the cathode 12 and the light emitting layer 110b, the light emission efficiency of the light emitting layer 110b. And device characteristics such as lifetime are improved. The hole injecting / transporting material may be different for each color of the light emitting layer 110b, or the hole injecting / transporting layer 110a may not be provided for the light emitting layer 110b of a specific color. Is possible.
[0038]
The light emitting layer 110b is a red light emitting layer 110b that emits red (R) light. ₁ Green light emitting layer 110b that emits green light (G) ₂ , And blue light emitting layer 110b emitting blue (B) ₃ , And each light emitting layer 110b ₁ ~ 110b ₃ Are arranged in stripes. Examples of the material of the light emitting layer 110b include (poly) paraphenylene vinylene derivatives, polyphenylene derivatives, polyfluorene derivatives, polyvinyl carbazole, polythiophene derivatives, perylene dyes, coumarin dyes, rhodamine dyes, or polymer materials thereof. In addition, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, quinacridone and the like can be used.
[0039]
The cathode 12 is configured by laminating a calcium (Ca) layer 12a and an aluminum (Al) layer 12b. The layer thickness of the calcium layer is preferably in the range of 2 to 50 nm, for example. The aluminum layer 12b reflects light emitted to the cathode 12 side to the substrate 2 side, and is preferably made of an Ag film, an Al / Ag laminated film, or the like in addition to the Al film. The thickness is preferably in the range of 100 to 1000 nm, for example. The cathode 12 is formed on the entire surface of the light emitting element portion 11. Then, it plays a role of flowing a current through the organic functional layer 110 in a pair with the pixel electrode 111. In addition, on the cathode 12, if necessary, SiO, SiO ₂ A protective layer for preventing oxidation made of SiN or the like may be provided.
[0040]
Next, a method for manufacturing the organic EL display device 1 of the present embodiment will be described with reference to the drawings. The manufacturing method of the organic EL display device 1 of the present embodiment includes, for example, (1) a bank part forming step, (2) a plasma processing step (3) a hole injection / transport layer forming step, (4) a light emitting layer forming step, (5) An electron injection / transport layer forming step, (6) a cathode forming step, and (7) a sealing step. In addition, a manufacturing method is not restricted to this, When other processes are removed as needed, it may be added. The (3) hole injection / transport layer forming step and (4) light emitting layer forming step were performed using a liquid discharge method (inkjet method) using a droplet discharge device.
[0041]
(1) Bank layer formation process
The bank layer forming step is a step of forming the bank layer 112 having the opening 112d at a predetermined position of the substrate 2. The formation method will be described below. First, as shown in FIG. 5, an element having a circuit element portion 14 such as a scanning line, a signal line, and a thin film transistor 123 on a substrate 2 and a plurality of pixel electrodes 111 formed on interlayer insulating films 144a and 144b. Prepare the board. Then, a photosensitive material (organic material) having heat resistance and solvent resistance such as acrylic resin or polyimide resin is applied on the substrate 2, and the opening 112 d is formed in the region where the pixel electrode 111 is disposed by dry etching technology. Form (see FIG. 6). This dry etching technique is a technique in which etching is performed using a plasma-ized etching gas as is well known, and the organic material constituting the bank layer 112 is not immersed in a chemical solution unlike the wet etching technique. For this reason, it is possible to reduce the possibility that moisture is contained in the bank layer 112 by forming the opening 112d using a dry etching technique. Note that the bank layer 112 is preferably formed by a dry etching technique, but the bank layer 112 can also be formed by a wet etching technique.
[0042]
(2) Plasma treatment process
The plasma treatment process is performed for the purpose of activating the surface of the pixel electrode 111 and further treating the surface of the bank layer 112. In particular, in the activation process, cleaning on the pixel electrode 111 and adjustment of the work function are mainly performed. Further, a lyophilic process on the surface of the pixel electrode 111 and a lyophobic process on the surface of the bank layer 112 are performed.
[0043]
(3) Hole injection / transport layer formation process
As shown in FIG. 7, the hole injection / transport layer 110a is formed on the substrate 2 on which the pixel electrode 111 is formed. In the hole injection / transport layer forming step, for example, a composition containing a hole injection / transport layer forming material is discharged onto the pixel electrode 111 by using a liquid discharge method. Thereafter, a drying process and a heat treatment are performed to form the hole injection / transport layer 110 a on the pixel electrode 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.
[0044]
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 pixel electrode 111 located in the opening of the bank portion 112, and the discharge head and the substrate 2 are moved relative to each other, and an ink droplet with a controlled liquid amount is discharged from the discharge nozzle. To do. 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.
[0045]
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.
[0046]
(4) Light emitting layer forming step
Next, as shown in FIGS. 8 and 9, a light emitting layer 110b is formed on the pixel electrode 111 on which the hole injection / transport layer 110a is stacked. In FIG. 8, the blue light emitting layer 110b. ₃ And subsequently, the red light emitting layer 110b as shown in FIG. ₁ Green light emitting layer 110b ₂ Are sequentially formed. Here, the composition ink containing the light emitting layer material is discharged onto the hole injection / transport layer 110a by a liquid discharge method, and then dried and heat-treated to emit light of each color in the opening formed in the bank portion 112. Layer 110b ₁ ~ 110b ₃ Form.
[0047]
In the light emitting layer forming step, non-polarity that is insoluble in the hole injecting / transporting layer 110a is used as a solvent for the composition ink used in forming the light emitting layer in order to prevent re-dissolution of the hole injecting / transporting layer 110a. Use solvent. 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 light emitting 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. The surface modifying solvent used here can be exemplified by cyclohexylbenzene, dihydrobenzofuran, trimethylbenzene, tetramethylbenzene, etc. as the same as the nonpolar solvent of the composition ink. Examples of the solvent are toluene, xylene and the like.
[0048]
As a procedure for forming a light emitting layer by a liquid discharge method, first, when forming a blue light emitting layer, as shown in FIG. ₃ And a discharge nozzle of the discharge head is made to face the blue (B) hole injection / transport layer 110a located in the opening of the bank 112, and the discharge head While moving relative to the substrate 2, 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, the non-polar solvent contained in the composition ink is evaporated by drying the discharged ink droplets, and the blue light emitting layer 110b is evaporated. ₃ Is formed.
[0049]
Blue light emitting layer 110b ₃ As the light-emitting material for forming, for example, a material made of an organic EL material such as distyrylbiphenyl and a derivative thereof, coumarin and a derivative thereof, tetraphenylbutadiene and a derivative thereof can be used. 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.
[0050]
Subsequently, as shown in FIG. 9, the red light emitting layer 110b is formed on the red (R) and green (G) pixel electrodes 111 on which the hole injection / transport layers 110a are stacked. ₁ And the green light emitting layer 110b ₂ Respectively. The red and green light emitting layer forming steps are performed in the same procedure as the blue light emitting layer forming step described above. That is, the green light emitting layer 110b is formed by a liquid discharge method. ₂ After the composition ink containing the material forming the material is discharged onto the hole injection / transport layer 110a for green (G), drying treatment and heat treatment are performed, and the green light emitting layer 110b is formed in the opening formed in the bank portion 112. ₂ Form. Further, the red light emitting layer 110b is formed by a liquid discharge method. ₁ After the composition ink containing the material forming the material is discharged onto the red (R) hole injection / transport layer 110a, it is dried and heat-treated, and the red light emitting layer 110b is formed in the opening formed in the bank portion 112. ₁ Form. The green light emitting layer 110b ₂ As the light emitting material for forming the light emitting layer, for example, a material made of an organic EL material such as quinacridone and its derivatives can be used, and the red light emitting layer 110b ₁ As the light-emitting material for forming, for example, a material made of an organic EL material such as rhodamine and its derivatives can be used.
[0051]
(5) Electron injection / transport layer formation process
Next, as shown in FIG. 10, an electron injection / transport layer 110 c is formed on the entire surface of the light emitting layer 110 b and the bank layer 112. The electron injecting / transporting layer 110c is preferably formed by a vapor deposition method, a sputtering method, a CVD method, or the like. In particular, the electron injection / transport layer 110c is preferably formed by a vapor deposition method from the viewpoint of preventing damage to the light emitting layer 110b due to heat.
[0052]
(6) Cathode formation process
Next, as shown in FIG. 11, a counter electrode (cathode) 12 that forms a pair with the pixel electrode (anode) 111 is formed. That is, the cathode 12 is formed by sequentially laminating the calcium layer 12a and the aluminum layer 12b on the entire surface of the substrate 2 including the light emitting layers 110b and the bank 112. Thereby, the cathode 12 is laminated | stacked on the whole formation area of each color light emitting layer 110b, and the organic EL element corresponding to each color of red (R), green (G), and blue (B) is formed, respectively. The cathode 12 is preferably formed by, for example, an evaporation method, a sputtering method, a CVD method, or the like, and particularly preferably formed by an evaporation method in terms of preventing damage to the light emitting layer 110b due to heat. Further, on the cathode 12, SiO 2 is used for preventing oxidation. ₂ A protective layer such as SiN may be provided.
[0053]
(7) Sealing process
Finally, the substrate 2 on which the display element unit 10 is formed and the sealing can 604 are sealed through a sealing resin 603. For example, a sealing resin 603 made of a thermosetting resin or an ultraviolet curable resin is applied to the peripheral portion of the substrate 2 and the sealing can 604 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.
[0054]
Thereafter, the cathode 12 is connected to the wiring of the substrate 2 and the wiring of the circuit element unit 14 (see FIG. 3) is connected to a driving IC (driving circuit) provided on the substrate 2 or outside. The organic EL display device 1 is completed.
[0055]
Therefore, even when the organic EL display device 1 is stored for a long period of time or at a high temperature, water that causes deterioration of the light emitting layer 110b does not occur from the bank layer 112. As a result, a decrease in luminance and dark spots due to moisture occur. It is possible to provide an electro-optic display device that is prevented from occurring.
[0056]
(Second Embodiment)
Next, a second embodiment of the organic EL device will be described with reference to FIGS. In the first embodiment, the light emitted from the organic functional layer 110 is emitted to the substrate 2 side, whereas in the present embodiment, the light is emitted to the sealing portion 3 side. Yes. The difference between the present embodiment and the first embodiment is mainly the material configuration, and in this embodiment, the parts different from the first embodiment will be described.
[0057]
In the present embodiment, light emission is extracted from the sealing portion 3 side, which is the opposite side of the substrate 2, so that either a transparent substrate or an opaque substrate can be used as the substrate 2. Examples of the opaque substrate include a thermosetting resin and a thermoplastic resin in addition to a ceramic sheet such as alumina and a metal sheet such as stainless steel that has been subjected to an insulation treatment such as surface oxidation.
[0058]
In addition, the pixel electrode 111 is not necessarily limited to a transparent material, and a suitable material satisfying the function of the anode is used, and a material having light reflectivity is preferable, and Al or the like is employed. In addition, when adopting transparent metal ITO etc. as the pixel electrode 111, the structure which forms Al thin film etc. in the lower layer, and has light reflectivity is preferable.
[0059]
Moreover, as a material of the cathode 12, it needs to have transparency and transparent metals, such as ITO, are employ | adopted. Here, an Al thin film having a transparent film thickness may be formed between the ITO and the electron injection / transport layer 110c. The film thickness having transparency is preferably 50 nm or less. By forming such an Al thin film, not only the electron injection property to the electron injection / transport layer 110c is promoted, but also the plasma damage when ITO is formed by sputtering is suppressed, and the cathode 12 is transmitted through The organic functional layer 110 can be protected from invading moisture and oxygen. Further, as the material of the sealing can 604, a suitable material having transparency such as glass or resin is employed.
[0060]
In the organic EL display device 1 configured as described above, the same effects as those of the first embodiment can be obtained, and the light emitted from the organic functional layer 110 can be emitted from the sealing portion 3 side.
[0061]
(Third embodiment)
FIG. 12 shows an embodiment of the electronic apparatus of the present invention. The electronic apparatus of this embodiment is equipped with the above-described electro-optic display device as a display unit. FIG. 12 is a perspective view showing an example of a mobile phone. Reference numeral 1000 denotes a mobile phone body, and reference numeral 1001 denotes a display unit using the organic EL display device 1 described above. As described above, the electronic apparatus including the electro-optical display device according to the electro-optical device of the present invention as the display unit can prevent the luminance from being reduced and the dark spot from being generated in the display unit.
[0062]
As mentioned above, although each embodiment of this invention was shown, this invention is not limited to these, It can change suitably within the range of the matter described in the claim, For example, this invention is applied to a plasma display apparatus etc. It is also possible to adopt. Within the scope of the matters described in the claims, the effects of the present invention can be manifested with respect to each appropriately modified item.
[0063]
【Example】
In order to demonstrate the effect of the present invention, the present inventors actually manufactured an organic EL display device having a configuration according to the present invention, and measured the number of dark spots generated. The results are reported below.
[0064]
Example 1
In this example, an organic EL display device similar to the organic EL display device 1 shown in FIGS. 1 to 4 was prepared in order to measure the number of dark spots generated. At this time, photocurable polyimide Toray Photonics PW-1000 (trade name) was used as the bank layer 112, and 30% silica gel was mixed as the filler 150 therein. In addition, BytronP CH8000 (trade name) is used as the hole injection / transport layer 110a, and a polymer-based light emitting material is formed thereon by patterning by an inkjet method to form a light emitting layer, and LiF is deposited by depositing 2 nm. / The transport layer 110c was formed, and the cathode 12 was formed by depositing 20 nm of Ca and 200 nm of Al. Furthermore, the sealing part 3 was formed by adhere | attaching protective glass with an epoxy resin. The bank layer 112 was formed by a wet etching technique.
[0065]
The organic EL display device thus formed was subjected to heat aging at 60 ° C. for 200 hours. As a result, 20 dark spots / cm ² 50 / cm when the filler 150 is not contained in the bank layer 112 under the same conditions. ² As can be seen from the comparison, it was found that the generation of dark spots can be prevented.
[0066]
(Example 2)
Next, photocurable polyimide Toray Photonics UR-3100 was used as the bank layer 112, 30% of calcium oxide fine particles (dehydrating material) were mixed therein, and other configurations were the same as in Example 1. The bank layer 112 is made of CF. ₄ It was formed by a dry etching technique using a gas.
[0067]
The organic EL display device thus formed was subjected to heat aging at 60 ° C. for 200 hours in the same manner as in Example 1. As a result, 2 dark spots / cm ² 20 / cm when silica gel which is not a dehydrating material is used as the filler 150 under the same conditions. ² As can be seen from the comparison, it was found that the generation of dark spots can be further prevented.
[Brief description of the drawings]
FIG. 1 is a wiring structure diagram of an electro-optic display device according to an embodiment of the present invention.
FIG. 2 is a plan view of the electro-optical display device.
FIG. 3 is a cross-sectional view taken along the line II ′ of FIG.
FIG. 4 is a cross-sectional view showing a main part of the electro-optical display device.
FIG. 5 is a process diagram illustrating a method for manufacturing an electro-optical display device.
FIG. 6 is a process diagram illustrating a method for manufacturing an electro-optical display device.
FIG. 7 is a process diagram illustrating the method of manufacturing the electro-optical display device.
FIG. 8 is a process diagram illustrating a method for manufacturing an electro-optical display device.
FIG. 9 is a process diagram illustrating the method for manufacturing the electro-optical display device.
FIG. 10 is a process drawing for explaining the manufacturing method of the electro-optical display device.
FIG. 11 is a process drawing for explaining the manufacturing method of the electro-optical display device.
FIG. 12 is a diagram showing an electronic apparatus according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Organic EL display device (electro-optic display device), 112 ... Bank layer (pixel interval wall), 150 ... Filler (filling), A ... Light emitting part (light emitting pixel)

Claims (4)

An opening is formed corresponding to the position where each pixel electrode is formed, and a pixel interval wall made of an organic material is disposed on each pixel electrode and in each pixel electrode within the opening of the pixel interval wall. An electro-optic display device comprising:
The electro-optical display device, wherein a dehydrating material is contained in the pixel interval wall as a filling made of a material having a lower molecular weight than the organic material.     The electro-optic display device according to claim 1, wherein a content ratio of the filler with respect to the pixel interval wall is 10% to 30%. A method of manufacturing an electro-optical display device according to claim 1 or 2,
The method of manufacturing an electro-optical display device, wherein the pixel interval wall is formed by a dry etching technique.     An electronic apparatus comprising the electro-optic display device according to claim 1.

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