Patent Application
20150137086
The present disclosure relates to an organic electroluminescence unit that emits light utilizing organic electroluminescence (EL; Electro Luminescence) phenomenon, to a method of manufacturing the organic electroluminescence unit, and to an electronic apparatus that includes the organic electroluminescence unit.
As development of information communication industry has been accelerated, a display device that has an advanced performance has been demanded. In such a circumstance, an organic EL device that has attracted attention as a next-generation display device has advantages that are not only a wide viewing angle and excellent contrast as a self-emitting-type display device, but also fast response time.
The organic EL device has a configuration in which a plurality of layers including a light emitting layer are laminated. These layers may be formed, for example, by a dry method such as a vacuum deposition method. Specifically, a general method may be a method in which a mask having an opening is sandwiched between a deposition source and a substrate, and a layer is patterned into a desired shape. In a display unit that uses such an organic EL device, when a size thereof is made larger or resolution thereof is made higher, the mask is curved and carrying thereof becomes complicated, which makes alignment difficult and decreases an opening rate. This causes an issue of decrease in device characteristics.
To address this, for example, Patent Literature 1 discloses a laser transfer method in which a transfer layer (an organic film) is formed on a donor film having concavities and convexities, and the organic film on the convex portion is transferred with the use of a laser. However, in this technique, the organic film is formed on the concavities and convexities, which causes an issue that it is difficult to maintain uniformity in thickness of the organic film.
Accordingly, Patent Literature 2 proposes a letterpress reverse offset printing method (hereinafter, simply referred to as “reverse offset printing method”) that uses a blanket. In the reverse printing method, ink that includes a light emitting material is applied onto the blanket, and an unnecessary region (a non-printing pattern) of an ink layer is then selectively removed with the use of an intaglio plate. By transferring, to a substrate to be printed, the blanket on which a printing pattern is thus formed, a light emitting layer is formed. In such a reverse printing method, the organic film is formed on a flat blanket, which makes it easy to form an organic film having a uniform thickness.
However, for example, in a display unit that has a dividing wall between devices as described in Patent Literature 3, when it is attempted to form an organic layer (for example, a light emitting layer) provided between the dividing walls by reverse printing, air intrudes between the light emitting layer and a substrate to be printed, and a printing pattern may not be transferred properly. For this reason, there has been an issue of decrease in light emitting characteristics.
Accordingly, it is desirable to provide an organic electroluminescence unit that suppresses intrusion of air at the time of printing with the use of a plate and has favorable light emitting characteristics, a method of manufacturing the organic electroluminescence unit, and an electronic apparatus.
An organic electroluminescence unit of an embodiment of the present technology includes: a plurality of light emitting devices arranged having a pitch from 10 micrometers to 60 micrometers both inclusive, and each including a first electrode, an organic layer, and a second electrode that are laminated in order from a substrate, the organic layer including at least a light emitting layer, and at least one layer in the organic layer being formed by a plate printing method; and a dividing wall provided between adjacent light emitting devices of the plurality of light emitting devices. In the organic electroluminescence unit, a difference between a height, from the substrate, of the dividing wall and a height, from the substrate, of a surface to be printed by the plate printing method is from 0 micrometer to 1 micrometer both inclusive.
A method of manufacturing an organic electroluminescence unit of an embodiment of the present technology includes the following (A) to (D), and a difference between a height of a dividing wall and a height of a surface to be printed by a plate printing method is caused to be from 0 micrometer to 1 micrometer both inclusive.
(A) forming a plurality of first electrodes having a pitch from 10 micrometers to 60 micrometers both inclusive
(B) forming a dividing wall between the plurality of first electrodes
(C) forming an organic layer on the plurality of first electrodes, the organic layer including at least a light emitting layer
(D) forming a second electrode on the organic layer
An electronic apparatus of an embodiment of the present technology includes the above-described organic electroluminescence unit.
In the organic electroluminescence unit of an embodiment of the present technology and in the method of manufacturing the organic electroluminescence unit, a difference in height between the surface to be printed by the plate printing method and the dividing wall provided between the light emitting devices in the light emitting devices that are arranged having the pitch from 10 micrometers to 60 micrometers both inclusive is caused to be 0 micrometer to 1 micrometer both inclusive. This suppresses intrusion of air between the surface to be printed and the organic layer when the organic layer including the light emitting layer in the light emitting device is formed by the plate printing method.
According to the organic electroluminescence unit of an embodiment of the present embodiment and the method of manufacturing the organic electroluminescence unit, the height of the dividing wall provided between the light emitting devices that are arranged having the pitch from 10 micrometers to 60 micrometers both inclusive is caused to have a difference, with the height of the surface to be printed by the plate printing method, from 0 micrometer to 1 micrometer both inclusive. This suppresses intrusion of air between the organic layer including the light emitting layer of the light emitting device and the surface to be printed at the time of printing, which allows the printing pattern to be transferred properly. This achieves favorable light emitting characteristics.
An embodiment of the present disclosure is described below in detail with reference to the drawings. Incidentally, the description is provided in the following order.
[1-1. Configurations of Surface to be Printed and Dividing Wall]
Part (A) of
In the reverse offset printing method that uses a blanket (hereinafter, simply referred to as “reverse printing method”), a predetermined printing pattern is formed on a blanket, and the printing pattern is then transferred onto a substrate to be printed. Specifically, for example, when the blanket has a substantially rectangular shape, the printing pattern is transferred by gradually pressing the blanket onto the substrate to be printed with the use of a roll or the like from an arbitrary end to another end. Here, when printing is performed on a region (that is, a concave portion) in which a level difference, that is higher than the surface to be printed, is formed in the periphery thereof, the printing pattern is formed larger than a bottom surface of the concave portion. Specifically, for example, when printing is performed between the dividing walls 12 that have cross-sections on trapezoids illustrated in
On the other hand, in the present embodiment, intrusion of gas is suppressed by defining a level difference between a surface to be printed (here, the first electrode 11) and side walls (here, the dividing walls 12) provided on both ends thereof. Specifically, when a pitch (a distance between center of one dividing wall 12a to center of another dividing wall 12b where the dividing walls 12a and 12b sandwich a light emitting region; I) is from 10 μm to 60 μm both inclusive, a difference (h) between a height (h1) of the dividing wall 12 and a height (h2) of the first electrode 11 may be preferably 1 μm or smaller. By causing the level difference to be 1 μm or smaller, the blanket on which the printing pattern is formed is bent sufficiently between the dividing walls, and may be brought into contact, for example, with from a top surface to a side surface on the dividing wall 12A side, from the first electrode 11 that is the surface to be printed to a side surface of the dividing wall 12b, and a top surface thereof in order. Thus, air in the opening portion 12A (air between the printing pattern and the first electrode 11) is removed in accordance with the contact of the blanket. This makes it possible to properly transfer, for example, the printing pattern of the light emitting layer 14 on the first electrode 11 with no air bubble mixed therein.
It is to be noted that the dividing wall 12 is provided so as to cover a peripheral portion of the first electrode 11. The dividing wall 12 has a height that is equivalent with that of the first electrode (h1=h2, h=0 μm) or higher (h1>h2). Also, although the details are described later, the dividing wall 12 is configured, for example, by forming a resin film by a spin coating method or the like, and then processing the formed resin film into a predetermined shape, for example, by photolithography or the like. Here, the shape of the cross-section of the dividing wall 12 may be a trapezoidal shape as illustrated in
[1-2. Overall Configuration of Display Unit]
The substrate 110 may be formed, for example, of a glass substrate, or a plastic substrate. Alternatively, the substrate 110 may be that in which a surface of quartz, silicon, metal, or the like is subjected to an insulating process. Alternatively, the substrate 110 may be flexible or rigid.
The gate electrode 1101 has a role of controlling carrier density in the semiconductor layer 1104 by a gate voltage to be applied to the TFT 111. The gate electrode 1101 may be configured, for example, of a single-layer film made of one of Mo, Al, aluminum alloy, etc. or a laminated film made of two or more thereof. Examples of the aluminum alloy may include aluminum-neodymium alloy.
The gate insulating films 1102 and 1103 may be each configured, for example, of a single-layer film made of one of a silicon oxide film (SiOx), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al2O2), etc., or a laminated film made of two or more thereof. Here, the gate insulating film 1102 may be configured, for example, of SiO2, and the gate insulating film 1103 may be configured, for example, of Si3N4. A total thickness of the gate insulating films 1102 and 1103 may be, for example, from 200 nm to 300 nm.
The semiconductor layer 1104 may be configured, for example, of an oxide semiconductor that includes, as a main component, at least one oxide of indium (In), gallium (Ga), zinc (Zn), tin (Sn), Al, and Ti. The semiconductor layer 1104 forms a channel between the pair of source-drain electrodes 1106 by application of the gate voltage. The semiconductor layer 1104 may desirably have a thickness of a degree that does not cause degradation in ON current of the thin film transistor so that an influence of a negative charge described later is given on the channel. Specifically, the semiconductor layer 1104 may desirably have a thickness from 5 nm to 100 nm.
The channel protection film 1105 is formed on the semiconductor layer 1104, and prevents damage of the channel at the time of forming the source-drain electrodes 1106. The channel protection film 1105 may be configured, for example, of an insulating film that includes silicon (Si), oxygen (O2), and fluorine (F), and may have a thickness, for example, from 10 nm to 300 nm.
The source-drain electrode 1106 serves as a source or a drain. The source-drain electrode 1106 may be configured, for example, of a single-layer film made of one of molybdenum (Mo), aluminum (Al), copper (Cu), titanium, ITO, titanium oxide (TiO), and the like, or may be a laminated film made of two or more thereof. For example, it may be desirable to use a tri-layer film configured of Mo, Al, and Mo laminated in order having thicknesses of 50 nm, 500 nm, and 50 nm, respectively. It may be also desirable to use metal or metal compound that has week bonding with oxygen, for example, metal compound that includes oxygen such as ITO or titanium oxide. Electric characteristics of the oxide semiconductor are stably retained thereby.
The planarization layer 112 may be configured, for example, of an organic material such as polyimide or novolac. The planarization layer 112 may have a thickness, for example, from 10 nm to 100 nm, and may preferably have a thickness of 50 nm or smaller. An anode electrode 12 of the organic EL device 2 is formed on the planarization layer 112.
It is to be noted that a contact hole H is provided in the planarization film 112. The source-drain electrode 1106 is electrically connected to each of the first electrodes 11 of the organic EL devices 2R, 2G, and 2B via the contact hole H. The first electrodes 11 are electrically separated for the respective pixels by the dividing walls 12. The organic layer 14 including the light emitting layers of the respective colors described later and the second electrode 16 are laminated on the first electrode 11. A detailed configuration of the organic EL devices 2R, 2G, and 2B is described later.
The protection layer 18 is for preventing intrusion of moisture into the organic EL devices 2R, 2G, and 2B. The protection layer 18 is configured of a material having low transmission characteristics and low water permeability, and may have a thickness, for example, from 2 μm to 3 μm. The protection layer 18 may be configured of any of an insulating material and a conductive material. As the insulating material, an inorganic amorphous insulating material, for example, amorphous silicon (α-Si), amorphous silicon carbide (α-SiC), amorphous silicon nitride (α-Si1-xNx), amorphous carbon (α-C), etc. may be mentioned. Such an inorganic amorphous insulating material does not configure a grain, and therefore has low water permeability, which achieves a favorable protection film.
The sealing substrate 20 seals the organic EL devices 2R, 2G, and 2B together with an adhesive layer 19. The sealing substrate 20 may be configured of a material such as glass transparent to light generated in the organic EL device 2. For example, a color filter and a black matrix (both are not illustrated) may be provided on the sealing substrate 20. In this case, light rays of the respective colors generated in the organic EL devices 2R, 2G, and 2B are extracted, and outside light reflected in the organic EL devices 2R, 2G, and 2B is absorbed, which improves contrast.
(Organic EL Devices 2R, 2G, and 2B)
Each of the organic EL devices 2R, 2G, and 2B may have, for example, a device structure of a top surface light emission type (a top emission type). However, each of the organic EL devices 2R, 2G, and 2B is not limited to such a configuration, and may be, for example, of a transmission type in which light is extracted from the substrate 110 side, i.e., of a bottom surface light emission type (a bottom emission type).
The organic EL device 2R is formed in the opening portion 12A in the dividing wall 12. The organic EL device 2R may be configured, for example, of the hole injection layer (HIL) 13B, the hole transfer layer (HTL) 13A, the red light emitting layer 14R, a blue light emitting layer 14B, an electron transfer layer (ETL) 15A, an electron injection layer (EIL) 15B, and the second electrode 16 that are laminated in order on the first electrode 11. This is similarly applicable to the organic EL device 2G. The organic EL device 2G may have, for example, a laminated structure in which the red light emitting layer 14R in the laminated structure of the organic EL device 2R is substituted by the green light emitting layer 14G. The organic EL device 2B may be configured, for example, of the hole injection layer 13B, the hole transfer layer 13A, the blue light emitting layer 14B, the electron transfer layer 15A, the electron injection layer 15B, and the second electrode 16 that are laminated in order on the first electrode 11. As described above, in the present embodiment, the red light emitting layer 14R and the green light emitting layer 14G are formed separately for each pixel, and the blue light emitting layer 14B is formed over the entire surface of the display region 110A and is shared by the respective pixels. Other than this, the hole injection layer 13B, the hole transfer layer 13A, the electron transfer layer 15A, and the electron injection layer 15B are provided to be shared by the respective pixels. Although detailed description is provided later, in the present embodiment, the red light emitting layer 14R and the green light emitting layer 14G are formed by a reverse printing method, and the blue light emitting layer 14B is formed by a vacuum deposition method.
The first electrode 11 may serve, for example, as an anode. When the display unit 1 is of a top surface light emission type, the first electrode 11 may be configured, for example, of a highly-reflective material such as aluminum, titanium, or chromium (Cr). It is to be noted that, when the display unit 1 is of a bottom surface light emission type, for example, a transparent conductive film made of a material such as ITO, IZO, or IGZO may be used.
As described above, the dividing wall 12 electrically insulates between the respective devices of the organic EL devices 2R, 2G, and 2B, and partitions the light emitting regions of the respective pixels. One of the organic EL devices 2R, 2G, and 2B is formed in each of the plurality of opening portions 12A formed by the dividing walls 12. The dividing wall 12 may be configured, for example, of an organic material such as polyimide, novolac resin, or acrylic resin. Alternatively, the dividing wall 12 may be configured of a lamination of the organic material and an inorganic material. Examples of the inorganic material may include SiO2, SiO, SiC, and SiN.
The hole injection layer 13B is a buffer layer for improving efficiency of hole injection into the light emitting layers of the respective colors, and preventing leakage. The hole injection layer 13B may preferably have a thickness, for example, from 5 nm to 200 nm, and more preferably, from 8 nm to 150 nm. A material configuring the hole injection layer 13B may be appropriately selected in a relationship with the materials of adjacent layers such as the electrode. However, examples of the material configuring the hole injection layer 13B may include polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, polythienylene vinylene, polyquinoline, polyquinoxaline, derivatives thereof, a conductive polymer such as a polymer including an aromatic amine structure in a main chain or a side chain, metal phthalocyanine (such as copper phthalocyanine), and carbon. Specific examples of the conductive polymer may include polydioxythiophene such as oligoaniline, oligoaniline, and poly(3,4-ethylenedioxythiophene) (PEDOT). Other than this, trade name Nafion (trademark) and trade name Liquion (trademark) available from H. C. Starck, trade name ELsource (trademark) available from Nissan Chemical Industries, Ltd., conductive polymer verazol available from Soken Chemical & Engineering Co., Ltd., etc. may be used.
The hole transfer layer 13A is for increasing efficiency of hole transfer into the light emitting layers of the respective colors. The hole transfer layer 13A may preferably have a thickness, for example, from 5 nm to 200 nm, and more preferably, from 8 nm to 150 nm, which may although depend on the overall configuration of the device. As a material configuring the hole transfer layer 13A, a polymer material that is soluble to an organic solvent, for example, polyvinyl carbazole, polyfluorene, polyaniline, polysilane, derivatives thereof, a polysiloxane derivative including aromatic amine in a side chain or a main chain, polythiophene, a derivative of polythiophene, polypyrrole, or 4,4′-bis(N-1-naphthyl-N-phenylamino)biphenyl (α-NPD) may be used.
The red light emitting layer 14R, the green light emitting layer 14G, and the blue light emitting layer 14B each cause recombination of an electron and a hole in response to application of an electric field, and thereby emit light. The light emitting layers of the respective colors may each preferably have a thickness from 10 nm to 200 nm, and more preferably, from 20 nm to 150 nm, which may although depend on the overall configuration of the device.
A material configuring each of the red light emitting layer 14R, the green light emitting layer 14G, and the blue light emitting layer 14B may be any material as long as the material is suitable for each of the light emitting color. Such a material may be a high molecular material (having a molecular weight, for example, of 5000 or more), or may be a low molecular material (having a molecular weight, for example, of 5000 or less). When using the low molecular material, for example, a mixed material including two or more of host materials and dopant materials may be used. When using the high molecular material, for example, the high molecular material may be used, for example, in a state of ink dissolved in an organic solvent. Alternatively, a mixed material including these low molecular material and high molecular material may be used.
As described above, in the present embodiment, the red light emitting layer 14R and the green light emitting layer 14G are formed by a reverse printing method that is a so-called wet method, and the blue light emitting layer 14B is formed by a vacuum deposition method that is a dry method. For this reason, the high molecular material is mainly used as the materials configuring the red light emitting layer 14R and the green light emitting layer 14G, and the low molecular material is mainly used for the blue light emitting layer 14B.
Examples of the high molecular material may include a polyfluorene-based high-molecular derivative, a (poly)p-phenylene vinylene derivative, a polyphenylene derivative, a polyvinylcarbazole derivative, a polythiophene derivative, a perylene-based pigment, a coumarin-based pigment, a rhodamine-based pigment, and mixtures in which a dopant material is mixed to these materials. Examples of the dopant material may include rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, nile red, coumarin 6, etc. may be mentioned. As the low molecular material, for example, benzine, styrylamine, triphenylamine, porphyrin, triphenylene, azatriphenylene, tetracianoquinodimethane, triazole, imidazole, oxadiazole, polyarylalkane, phenylenediamine, arylamine, oxazole, anthracene, fluorenone, hydrazone, stilbene, derivatives thereof, and a heterocyclic conjugated monomer or oligomer such as polysilane-based compounds, vinylcarbazole-based compounds, thiophene-based compounds, and aniline-based compounds. Further, the light emitting layer of each of the colors may include, as a guest material, a material having high light emission efficiency, for example, a low-molecular fluorescent material, phosphorescent pigment, metal complex, etc. other than the above-described materials.
The electron transfer layer 15A is for increasing efficiency of electron transfer to the light emitting layers of the respective colors. Examples of a material configuring the electron transfer layer 15A may include quinoline, perylene, phenanthroline, bisstyryl, pyrazine, triazole, oxazole, fullerene, oxadiazole, fluorenone, derivatives thereof, and metal complexes thereof. Specifically, tris(8-hydroxyquinoline)aluminum (abbreviated as Alq3), anthracene, naphthalene, phenanthrene, pyrene, anthracene, perylene, butadiene, coumarin, C60, acridine, stilbene, 1,10-phenanthroline, derivatives thereof, or metal complexes thereof may be mentioned. Other than this, an organic material that has a superior electron transfer performance may be preferably used. Specific examples thereof may include an arylpyridine derivative, and a benzoimidazole derivative. A total thickness of the electron transfer layer 15A and the electron injection layer 15B may be preferably, for example, from 5 nm to 200 nm, and more preferably, from 10 nm to 180 nm, which although depends on the overall configuration of the device.
The electron injection layer 15B is for increasing efficiency of electron injection into the light emitting layers of the respective colors. Examples of a material configuring the electron injection layer 15B may include alkali metal, alkaline-earth metal, rare-earth metal, oxides thereof, composite oxides thereof, fluorides thereof, and carbonates thereof.
The second electrode 16 may have, for example, a thickness of about 10 nm. In a case of the top surface light emission type, the second electrode 16 may be configured of a single-layer film of a conductive film material that has light transmission characteristics, or a laminated film including two or more thereof. Examples of such a conductive film material may include ITO, IZO, ZnO, InSnZnO, MgAg, and Ag. In a case of the bottom surface light emission type, for example, a high reflectance material such as aluminum, AlSiC, titanium, or chromium may be used.
[1-2. Manufacturing Method]
The display unit 1 as described above may be manufactured as follows, for example.
First, as illustrated in
Subsequently, as illustrated in
Subsequently, as illustrated in
(Formation Step of G and R Light Emitting Layers)
Next, as illustrated in
1. Formation of first light emitting layer 14R
(1) Apply solution including a first light emitting material on the blanket.
(2) Form a printing pattern on the blanket with the use of an intaglio plate.
(3) Transfer the printing pattern on the blanket onto the drive substrate 10.
2. Formation of the second light emitting layer 14G
(1) Apply solution including a second light emitting material onto a blanket.
(2) Form a printing pattern on the blanket with the use of an intaglio plate.
(3) Transfer the printing pattern on the blanket onto the drive substrate 10.
1. Formation of First Light Emitting Layer
First, a blanket 60 is prepared that is used when a first light emitting layer (here, the red light emitting layer 14R) is transferred. Solution D1r that includes a red light emitting material is applied to be formed on the blanket 60. Specifically, as illustrated in Parts (A) and (B) of
(2) Printing Pattern Formation Step
Subsequently, a printing pattern layer (a printing pattern layer 14g1) of the red light emitting layer 14R is formed on the blanket 60. Specifically, first, as illustrated in Part (A) of
(3) Transfer Step
Subsequently, the printing pattern layer 14R1 of the red light emitting layer 14R on the blanket 60 is transferred onto the drive substrate 10 side. Specifically, first, as illustrated in Part (A) of
2. Formation of Second Light Emitting Layer
Subsequently, a blanket 62 that is used when a second light emitting layer (here, the green light emitting layer 14G) is prepared, and solution D1g including a green light emitting material is applied to be formed on the blanket 62. Specifically, as illustrated in Parts (A) and (B) of
(2) Printing Pattern Formation Step and (3) Transfer Step
Subsequently, although not particularly illustrated, a printing pattern layer of the green light emitting layer is formed on the blanket 62 with the use of a predetermined intaglio plate, and the formed printing pattern layer is transferred onto the drive substrate 10 side, in a manner similar to that in the case of the above-described green light emitting layer 14R. Thus, the green light emitting layer 14G is formed on the drive substrate 10a.
Next, as illustrated in
Subsequently, as illustrated in
Lastly, the protection layer 18 is formed so as to cover the organic EL devices 2R, 2G, and 2B on the drive substrate 10, and then the sealing substrate 20 is attached thereto with the adhesive layer 19 in between. Thus, the display unit 1 illustrated in
[Functions and Effects]
In the display unit 1 of the present embodiment, the scanning signal is supplied from the scanning line drive circuit 130 to each of the pixels via the gate electrode of the writing transistor Tr2, and the image signal is retained in the retentive capacity Cs from the signal line drive circuit 120 via the writing transistor Tr2. Thus, a drive current Id is injected into the organic EL device 2, and a hole recombines with an electron, which causes light emission. This light may pass through the second electrode 16 and the sealing substrate 20, and may be extracted to the above of the display unit 1, for example, in the case of the top surface light emission type.
In such a display unit, in the manufacturing process, for example, when the light emitting layers (the red light emitting layer 14R and the green light emitting layer 14G) are formed by a reverse printing method with the use of a blanket in the light emitting region partitioned by the dividing wall as described above, gas may intrude between the surface to be printed and the printing pattern formed on the blanket due to the level difference between the dividing wall and the surface to be printed, which may cause the printing pattern not to be transferred properly or may cause a gas bubble to be formed.
On the other hand, in the present embodiment, the level difference between the surface to be printed (for example, the first electrode 11) and the dividing wall 12 is caused to be 1 μm or smaller. This causes the blanket on which the printing pattern is formed to be brought in contact, in the transfer step, for example, with from the top surface to the side surface of the dividing wall 12A side, from the first electrode 11 serving as the surface to be printed to the side surface and the top surface of the dividing wall 12b in order. In other words, air in the opening portion 12A (air between the printing pattern and the first electrode 11) is gradually removed from a direction of pressing of the surface to be printed and the blanket. This suppresses intrusion of air (remaining of an air bubble) between the surface to be printed and the printing pattern. Specifically, this suppresses occurrence of transfer defects such as wrinkle in the printing pattern, tear of the printing pattern resulting from break of the intruded air, and failing in transfer of the printing pattern onto the first electrode. Consequently, the printing pattern is allowed to be transferred properly, which makes it possible to provide a display unit exhibiting favorable light emitting characteristics.
Next, a modification according to the above-described embodiment is described. A component similar to that in the above-described embodiment is designated with the same numerals, and description thereof is omitted where appropriate.
The display units 1 to 3 including the organic EL devices 2R, 2G, and 2B described in the above embodiment and Modification 1 may be mounted on an electronic apparatus in any field that performs image (or video) display as described below, for example.
Next, Examples of the present technology are described.
First, using the display unit 1 illustrated in
As can be seen from Table 1, in a range of the pitch from 21 μm to 60 μm both inclusive, a transfer defect occurred when the level difference (h) was 1.5 or larger, and a defect portion was observed in part of the printing pattern when the level difference (h) was 1.2 μm. Further, in a case where the pitch was 17 μm, a complete transfer defect occurred when the level difference (h) was 1.2 μm. As described above, it was found that proper transfer of the printing pattern is possible by causing the difference between the height (h1) of the side wall and the height (h2) of the surface to be printed to be 1.0 μm or smaller where the pitch is from 17 μm to 60 μm both inclusive. It is to be noted that the thickness of the support base of the silicon blanket is not particularly limited. Here, the PET base and the glass base having the thickness from 100 μm to 750 μm were used. However, this is not limitative. For example, the thickness thereof may be from 50 μm to 1 mm both inclusive. Moreover, also the thickness of the silicon rubber is not particularly limited, but may be, for example, from 10 μm to 1 mm both inclusive.
The present disclosure is described above referring to the embodiment and the modification. However, the present disclosure is not limited to the above-described embodiment and the like, and various modifications may be made. For example, in the above-described embodiment and the like, the red light emitting layer is formed first as the first light emitting layer formed by a reverse printing method, and then the green light emitting layer is formed as the second light emitting layer formed by a reverse printing method. However, the formation steps of the light emitting layers of the respective colors may be opposite.
Moreover, as the charge transfer material in the present disclosure, an appropriate hole transfer material or an appropriate electron transfer material may be selected depending on the order of formation of the light emitting layers, device characteristics in the respective pixels, etc.
Moreover, in the above-described embodiment, the blanket and the substrate to be printed (the drive substrate 10) are each described with a parallel flat plate as an example (a parallel flat plate—a parallel flat plate). However, this is not limitative. One of the blanket and the substrate to be printed may have a roll shape (a roll—a parallel flat plate, a parallel flat plate—a roll), or both of them may have a roll shape (a roll—a roll). Moreover, the shape of the pixels partitioned by the dividing walls 12 is not particularly limited, and may be, for example, a square having four sides of the same length, or may be a rectangular. Further, the pressing direction of the blanket at the time of printing is not particularly limited, and may be a major-axis direction or a minor-axis direction of the respective pixels.
Moreover, the material and the thickness or the deposition method and the deposition condition, etc. of each of the layers described in the above embodiment and the like are not limitative, and other material and thickness may be used, or other deposition method and deposition condition may be used. Moreover, it is not necessary to provide all of the respective layers described in the above embodiment and the like, and some may be omitted where appropriate. Further, a layer other than the layers described in the above embodiment and the like may be additionally provided. For example, one or a plurality of layers that each use a material having a hole transfer performance as with a common hole transfer layer described in Japanese Unexamined Patent Application Publication No. 2011-233855 may be additionally provided between the charge transfer layer 17 and the blue light emitting layer 14B in the blue EL device 2B. By additionally providing such a layer, light emission efficiency and life characteristics of the blue organic EL device 2B are improved.
It is to be noted that the present technology may also achieve the following configurations.
(1) An organic electroluminescence unit including:
a plurality of light emitting devices arranged having a pitch from 10 micrometers to 60 micrometers both inclusive, and each including a first electrode, an organic layer, and a second electrode that are laminated in order from a substrate, the organic layer including at least a light emitting layer, and at least one layer in the organic layer being formed by a plate printing method; and
This application claims priority on the basis of Japanese Patent Application JP 2012-126420 filed Jun. 1, 2012 in Japanese Patent Office, the entire contents of which are incorporated herein by reference.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-126420 | Jun 2012 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/063124 | 5/10/2013 | WO | 00 |
