JP4018430B2 - Organic EL device and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic EL element and a method for manufacturing the same, and more particularly to a light collecting structure for improving the external extraction efficiency.
[0002]
[Prior art]
A perspective view of an EL display panel using an organic EL element is shown in FIG. In an EL display panel, a plurality of strip-like ITO (Indium Tin Oxide) translucent electrodes (first electrodes) 3 are arranged on a glass substrate (translucent substrate) 1 along the direction of arrow a. Has been. A plurality of strip-shaped organic EL layers 4 are arranged on the ITO translucent electrode 3 along the arrow b direction.
[0003]
Further, an upper electrode (second electrode) 5 composed of a plurality of strip-like chromium (Cr) thin film patterns is disposed on each organic EL layer 4 so as to overlap therewith. The ITO translucent electrode 2, the organic EL layer 4 and the upper electrode 5 are covered and sealed on the glass substrate 1 with a seal (not shown). Then, nitrogen is sealed in the seal.
[0004]
If a voltage is applied to such an EL display panel by selecting a predetermined ITO translucent electrode 3 and a predetermined upper electrode 5, the selected ITO translucent electrode 3 and the upper electrode 5 A voltage is applied to the organic EL layer 4 located at the intersection, and the organic EL layer is excited to emit light. Therefore, by controlling the selection of the ITO translucent electrode 3 and the upper electrode 5, it is possible to perform a desired display using an EL display panel.
[0005]
A method for manufacturing this conventional organic EL element will be described below. Generally, a glass substrate 1 coated with ITO is prepared, and the ITO on the glass substrate 1 is etched using a resist pattern formed by photolithography as a mask, so that a predetermined pattern of ITO translucency is obtained. The electrode 3 is formed. Then, the glass substrate 1 on which the ITO translucent electrode 3 is formed is placed in a vacuum, and the organic EL layer 4 and the upper electrode 5 are formed by a vapor deposition technique. Thereafter, the seal is fixed and sealed in a nitrogen atmosphere.
[0006]
By the way, the external extraction efficiency in the conventional organic EL element is considered to be very low at about 20%.
It can be considered that most of the excited and emitted light is guided in the element (or substrate) and is hardly extracted to the outside by absorption or reflection in the waveguide.
This is one of the main reasons why the growth of the light emitting efficiency of the surface light emitting elements has been sluggish despite the recent remarkable technological advances in flat display panels (FPDs) such as organic EL elements.
Various attempts have been made in the past to overcome this problem, but no sufficient solution has been reported yet.
[0007]
That is, as shown in FIGS. 12 (a) and 12 (b), the structure explanatory view and the optical waveguide are shown in FIGS. 12 (a) and 12 (b). The light L is spread at the interface between the glass substrate 1 and the translucent electrode 3 and often exceeds the critical angle on the outer surface of the glass substrate 1 and is reflected inside by the reflection at the interface. It is considered that sufficient luminous efficiency cannot be obtained because of a large amount of returning so-called return light.
[0008]
Further, in order to reduce attenuation in the substrate, it is desirable that the thickness of the glass substrate is small. However, if the thickness is small, there is a problem that sufficient strength as a support cannot be obtained.
[0009]
Therefore, a structure in which a film for performing optical amplification is interposed between a substrate and a translucent electrode has been proposed.
This is a structure in which a porous body called silica airgel is interposed between the glass substrate 1 and the translucent electrode 3. Silica airgel is a porous body having a homogeneous ultrafine structure obtained by supercritical drying of a wet gel formed by a sol-gel reaction of silicon alkoxide.
[0010]
This porous body is expected to be put to practical use in optical design and electronic material design, which has been difficult in the past because its optical refractive index and dielectric constant are as small as air.
[0011]
[Problems to be solved by the invention]
However, silica airgel actually has a problem that resistance to an organic solvent is small, and cleaning using an organic solvent cannot be used in a subsequent process.
[0012]
This is a very serious problem in the process of manufacturing an actual device. That is, after forming the silica airgel layer, sputtering the ITO thin film as a translucent electrode and patterning it, forming the organic light emitting layer, forming the upper second electrode and patterning it An organic solvent such as isopropyl alcohol (IPA) is essential, and there is a problem that it is extremely difficult to form an element without using an organic solvent.
[0013]
In addition, the mechanical strength is not sufficient, breakage may occur, and there are problems such as a decrease in adhesion with a glass substrate or a translucent electrode. It was in a state.
[0014]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an organic EL element with high reliability by improving luminous efficiency.
[0015]
[Means for Solving the Problems]
Therefore, the present invention is characterized in that the pores have orientation between the translucent substrate and the translucent first substrate, and an inorganic porous solid thin film having a porosity of 50% or more is interposed. To do.
[0016]
That is, the first of the present invention is a light-transmitting substrate, an inorganic porous solid thin film formed on the surface of the light-transmitting substrate, with pores having orientation and a porosity of 50% or more, and the inorganic A translucent first electrode formed on the porous solid thin film; an organic EL layer formed on the transparent first electrode; and a second electrode formed on the organic EL layer. It is characterized by that.
[0017]
  According to this configuration, the pores have orientation, and the inorganic porous solid thin film having a porosity of 50% or more is interposed between the translucent substrate and the translucent first electrode. The light emission of the organic EL layer can be led out to the outside satisfactorily by the intervention of the low refractive index thin film, and the light emission efficiency can be improved. Since the refractive index of air is low, it is possible to achieve an extremely low refractive index of the film. In addition, it is possible to provide an organic EL element that has good mechanical strength and high reliability.
  In addition, since it is an inorganic porous solid thin film, it is highly resistant to organic solvents such as IPA, and has sufficiently high resistance in subsequent processes..
[0018]
Preferably, the inorganic porous solid thin film is configured such that a refractive index is smaller than a refractive index of the translucent substrate.
According to such a configuration, the light emission of the organic EL layer is favorably led to the outside by the intervention of the low refractive index thin film, and the light emission efficiency can be improved.
[0019]
Desirably, the pores of the inorganic porous solid thin film are formed on the substrate surface and have orientation.
According to this configuration, since the holes have orientation and have a periodic porous structure, the mechanical strength can be increased, and a highly reliable insulating film can be obtained.
[0020]
Desirably, the inorganic porous solid thin film has a periodic porous structure including cylindrical holes formed on a substrate surface and oriented so as to be parallel to the substrate surface. And
[0021]
According to this configuration, since the holes are oriented so as to be parallel to the substrate surface, the refractive index is uniformly low in the direction perpendicular to the substrate surface, and the entire take-out surface is uniform and reliable. It plays a role as a highly effective low refractive index thin film.
[0022]
Preferably, each of the adjacent porous structure domains includes a plurality of periodic porous structure domains including cylindrical holes formed on the substrate surface and oriented in one direction so as to be parallel to the substrate surface. Are characterized by being oriented in different directions.
[0023]
According to such a configuration, since the porous structure is oriented in a different direction for each domain, it becomes possible to close the openings of the pores to each other, and has excellent moisture resistance comparable to that of a dense film. It is possible to obtain a low-refractive-index thin film having an extremely low refractive index having a periodic structure and excellent mechanical strength. Furthermore, since the adjacent layers support the space between the layers, it is possible to construct a layered periodic porous shape that is normally considered unstable with a stable and excellent mechanical strength.
[0024]
Preferably, the translucent substrate is a flexible substrate.
[0025]
When the translucent substrate is a flexible substrate, the mechanical strength and supportability of the film formed in the upper layer are particularly serious problems. According to such a configuration, the mechanical strength is good and the substrate is in close contact with the substrate. Therefore, it is possible to obtain a highly reliable organic EL element.
[0026]
In the second aspect of the present invention, a light-transmitting substrate, an inorganic porous solid thin film formed on the surface of the light-transmitting substrate, having pores with orientation and a porosity of 50% or more, and the inorganic porous material An organic EL element portion formed on the porous solid thin film, and a drive element portion formed on the inorganic porous solid thin film, the organic EL element portion having a predetermined shape on the inorganic porous solid thin film A strip-shaped translucent first electrode formed at intervals, an organic EL layer formed on the transparent first electrode, and formed on the organic EL layer and orthogonal to the first electrode A plurality of organic EL elements, and the driving element portion is formed on the inorganic porous solid thin film, and includes the inorganic porous electrode. The organic EL element part is connected on or below the porous solid thin film.
[0027]
According to such a configuration, the above-mentioned organic EL element part with improved luminous efficiency can be formed on the same substrate, and the same inorganic porous solid thin film is used as the low dielectric constant thin film, Since it is formed, it is possible to obtain an organic EL device that has high adhesion with each part and that is fast and highly reliable.
In the drive circuit section, a wiring section having a multilayer wiring structure using the inorganic porous solid thin film as an interlayer insulating film is configured, and the active element is mounted as a chip element on a contact formed in the wiring section. Since an insulating film having a low dielectric constant can be formed, high speed and high reliability can be achieved.
In addition, when a semiconductor layer is formed on an inorganic porous solid thin film and an element region is formed in the semiconductor layer, the inorganic porous solid thin film has a good orientation. It becomes possible to form.
[0028]
In the third aspect of the present invention, a step of forming an inorganic porous solid thin film on a translucent substrate, a step of forming a lower electrode on the inorganic porous solid thin film, and an organic EL layer on the lower electrode A step of forming an upper electrode on the organic EL layer, the step of forming the inorganic porous solid thin film forming a precursor solution containing a silica derivative and a surfactant, and the precursor A contact step in which the solution is brought into contact with the substrate surface, a pre-crosslinking step in which the precursor solution is heated to start a cross-linking reaction before or after the contact step, and the cross-linking reaction is started in the pre-crosslinking step. Firing the translucent substrate with which the precursor solution is brought into contact, and decomposing and removing the surfactant.
[0029]
According to such a configuration, it is possible to provide an inorganic porous solid thin film having excellent controllability, excellent mechanical strength, and an extremely low refractive index. Further, since it can be formed at a low temperature, it is possible to form a highly reliable low refractive index film without affecting the base. In addition, since this inorganic porous solid thin film has high resistance to an organic solvent such as IPA, it can be formed without being restricted by a cleaning process in a subsequent patterning process or the like, so that a highly reliable organic EL element is efficiently formed. It becomes possible.
Furthermore, a highly reliable insulating film can be formed without affecting the base even when used as an interlayer insulating film on a substrate in which integrated circuits are mixed.
Further, the porosity can be appropriately changed by adjusting the concentration of the precursor liquid, and an inorganic porous solid thin film having a desired refractive index can be formed with extremely high workability.
[0030]
Preferably, the contacting step is a step of immersing the substrate in the precursor solution.
According to this configuration, it is possible to form the low refractive index insulating film with high productivity.
[0031]
Preferably, the contacting step is a step of immersing the substrate in the precursor solution and pulling it up at a desired speed.
According to this configuration, it is possible to form the low refractive index insulating film with high productivity.
[0032]
Preferably, the contact step is a step of applying the precursor solution onto a substrate.
According to this configuration, it is possible to form the low refractive index insulating film with high productivity.
[0033]
Preferably, the contact step is a spin coating step of dropping the precursor solution onto the substrate and rotating the substrate.
According to such a configuration, the film thickness and the porosity can be easily adjusted, and the low refractive index insulating film can be formed with high productivity.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of an organic EL device and a method for producing the same according to the present invention will be described. FIG. 1 is an explanatory diagram of the structure of the organic EL element of this embodiment. FIG. 1A is a sectional view, and FIG. 1B is an explanatory view of the structure of the inorganic porous solid thin film. FIG. 2A is a diagram showing a light emission waveguide path of the organic EL element of the present embodiment, and FIG.
[0035]
The EL display panel formed using this organic EL element is the same as that shown in FIG. 11 except that the inorganic porous solid thin film 2 is interposed between the glass substrate and the ITO transparent electrode.
As shown in FIG. 1A, this organic EL element has a structure shown in FIG. 1B between a translucent substrate 1 made of a glass substrate and an ITO electrode as a translucent first electrode. As shown in a schematic diagram for explanation, an inorganic porous solid thin film 2 having a porosity of 70%, in which cylindrical holes are oriented, is interposed.
[0036]
That is, the organic EL element includes a light-transmitting substrate 1 made of a glass substrate having a refractive index n = 1.52, and an inorganic porous solid having a refractive index n = 1.2 formed on the surface of the light-transmitting substrate 1. A thin film 2, a first electrode 3 made of an indium tin oxide (ITO) transparent conductive film having a refractive index n = 1.92 formed on the inorganic porous solid thin film 2, and formed on the first electrode 3 A hole transport layer (not shown) composed of N, N′-diphenyl-4,4′-diamine (hereinafter abbreviated as TPD) and the like, and an organic EL layer composed of 8-Hydirixyquinolin Aluminum (hereinafter abbreviated as Alq) 4, an electron injection layer (not shown) made of calcium oxide CaO or the like formed on the organic EL layer 4, and a metal second electrode 5 made of Cr formed on the electron injection layer. It will be.
[0037]
When a DC voltage is applied to the organic EL element having such a configuration, holes are injected from the first electrode 3 into the organic EL layer 4 through the hole transport layer, and from the cathode 6 through the electron injection layer 5 to the organic EL layer. 4 is injected with electrons. In the organic EL layer 4, recombination of holes and electrons occurs, and a light emission phenomenon occurs when excitons generated thereby shift from the excited state to the ground state. In this case, green light emission is obtained.
[0038]
The light thus generated in the organic EL layer 4 passes through the first electrode 3, the inorganic porous solid thin film 2, and the translucent substrate 1 as shown in FIGS. 2 (a) and 2 (b). Derived.
[0039]
Here, since the refractive index of the inorganic porous solid thin film 2 is about 1.2, it has a light condensing property before exiting from the glass to the air at the interface between the first electrode 3 and the inorganic porous solid thin film 2, and The light can be extracted efficiently. Therefore, it is guided forward well without being reflected at this interface. Thus, by sandwiching the low refractive index inorganic porous solid thin film between the translucent substrate and the translucent first electrode 3 made of ITO or the like, the amount of light guided forward increases. It can be seen as a thing. For example, when the refractive index n1 = 1.9 of ITO, the refractive index n2 = 1.5 of the glass substrate of the translucent substrate, and the refractive index n3 = 1.2 of the inorganic porous solid thin film 2, this inorganic porous solid By sandwiching the thin film 2, the amount of light was about 1.3 times.
[0040]
Next, the manufacturing process of the organic EL element of this embodiment is demonstrated.
First, as shown in FIG. 3A, cylindrical holes h that are oriented in one direction so as to be parallel to the surface of the light-transmitting substrate 1 are formed on the surface of the glass substrate as the light-transmitting substrate 1. A mesoporous silica thin film is formed so as to include a plurality of periodic porous structure domains (FIG. 1B).
[0041]
First, as shown in FIG. 4 (a), first, as a surfactant, cationic cetyltrimethylammonium bromide (CTAB: C₁₆H₃₃N⁺(CH_Three)_ThreeBr^-), Tetramethoxysilane (TMOS) as a silica derivative, and hydrochloric acid (HCl) as an acid catalyst,₂Dissolve in an O / alcohol mixed solvent and prepare a precursor solution in a mixing vessel. The precursor solution was charged at a molar ratio of 100 as a solvent, mixed as a surfactant 0.05, a silica derivative 0.1, and an acid catalyst 2, and the translucent substrate 1 was immersed in the mixed solution. As shown in FIG. 3 (b), after sealing the mixing vessel, the silica derivative is polymerized by hydrolysis polycondensation reaction by maintaining at 30 to 150 ° C. for 1 to 120 hours (preliminary crosslinking step), and the interface A mesoporous silica thin film is formed using a periodic self-aggregate of the activator as a template.
[0042]
This self-aggregate is C as shown in FIG.₁₆H₃₃N⁺(CH_Three)_ThreeBr^-A spherical micelle structure (FIG. 5 (b)) is formed by aggregating a plurality of molecules having a single molecule as a molecule, and the portion where the methyl group is removed becomes hollow as the degree of aggregation is increased by increasing the concentration (FIG. 5). 5 (c)), a cylindrical body (FIG. 5 (d)) in which columnar holes are oriented is formed.
Then, the substrate is pulled up, washed with water and dried, and then heated and baked in an oxygen atmosphere at 400 ° C. for 3 hours to completely thermally decompose and remove the mold surfactant, thereby forming a pure mesoporous silica thin film. This mesoporous silica thin film is divided into a plurality of domains, and is a porous thin film in which pores are oriented in each domain.
[0043]
Next, as shown in FIG. 3B, an ITO transparent electrode is formed as the translucent first electrode 3 by sputtering. Here, the evaporation atoms are evaporated from an evaporation source provided in the vacuum vessel, and the evaporation atoms are given onto the inorganic porous solid thin film 2 on the surface of the translucent substrate 1 through a shadow mask. Thereby, the ITO transparent electrode 3 having a predetermined strip pattern is formed.
[0044]
Next, as shown in FIG. 3C, the evaporated atoms are evaporated from another evaporation source, and the evaporated atoms are given to the inorganic porous solid thin film 2 and the transparent first electrode 3 through the shadow mask. Thereby, the organic EL layer 4 having a predetermined pattern is formed.
[0045]
Subsequently, as shown in FIG. 3D, the evaporation atoms are evaporated from another evaporation source, and the evaporation atoms are supplied through the shadow mask, so that the pattern of the second electrode 5 is formed.
[0046]
In this way, an organic EL element is formed. Then, in a nitrogen atmosphere, a seal (not shown) such as a glass cap or a metal cap is attached and sealed to complete an EL display panel. The seal is bonded and fixed to the translucent substrate 1 with an epoxy resin, an ultraviolet curable resin, or the like.
Further, in the above method, since the pattern formation is performed through the shadow mask rather than the electrode pattern formation by etching, there are few substrate cleaning steps, but at least the final cleaning is performed by IPA.
[0047]
According to such a configuration, since the low refractive index thin film made of a mesoporous silica thin film is formed on the entire surface of the translucent substrate, the incident angle of light with respect to the interface between the translucent substrate and the air layer can be increased. Therefore, it is possible to improve the light emission efficiency.
[0048]
In addition, since the holes are oriented so as to be parallel to the substrate surface, it has a low refractive index uniformly in a direction perpendicular to the substrate surface, and has no openings particularly for the upper and lower layers. An effective low refractive index thin film that can have a closed structure and has excellent moisture resistance and high reliability. Accordingly, the organic EL element has a long lifetime and high reliability.
[0049]
The composition of the precursor solution is not limited to the composition of the above embodiment, and the solvent is 100, the surfactant is 0.01 to 0.1, the silica derivative is 0.01 to 0.5, the acid catalyst. 0 to 5 is desirable. By using the precursor solution having such a configuration, it is possible to form a low dielectric constant insulating film having cylindrical holes.
[0050]
In the above-described embodiment, a cationic cetyltrimethylammonium bromide (CTAB: C) is used as the surfactant.₁₆H₃₃N⁺(CH_Three)_ThreeBr^-However, the present invention is not limited to this, and it goes without saying that other surfactants may be used.
[0051]
However, if alkali ions such as Na ions are used as a catalyst, the semiconductor material may be deteriorated. Therefore, it is desirable to use a cationic surfactant and an acid catalyst as the catalyst. Acid catalysts include HCl and nitric acid (HNO_Three), Sulfuric acid (H₂SO_Four), Phosphoric acid (H_ThreePO_Four), H_FourSO_FourEtc. may be used.
[0052]
Moreover, as a silica derivative, it is desirable to use silicon alkoxide materials, such as tetraethoxysilane (TEOS: Tetraethoxy Silane), without being limited to TMOS.
[0053]
The solvent is water H₂Although an O / alcohol mixed solvent was used, water alone may be used.
Furthermore, although an oxygen atmosphere is used as the firing atmosphere, it may be in the air, under reduced pressure, or in a nitrogen atmosphere. Desirably, by using a forming gas made of a mixed gas of nitrogen and hydrogen, the moisture resistance is improved and the leakage current can be reduced.
[0054]
Further, the mixing ratio of the surfactant, the silica derivative, the acid catalyst, and the solvent can be appropriately changed.
[0055]
Further, in the prepolymerization step, the temperature is maintained at 30 to 150 ° C. for 1 to 120 hours, preferably 60 to 120 ° C., more preferably 90 ° C.
Moreover, although the baking process was 400 degreeC for 1 hour, it is good also as about 1 to 5 hours at 300 to 500 degreeC. Desirably, the temperature is 350 ° C to 450 ° C.
[0056]
Furthermore, the precursor liquid is brought into contact with the substrate after the preliminary polymerization step, but the precursor liquid may be applied as it is.
[0057]
In the embodiment, the pattern is formed through the shadow mask. However, the electrode pattern may be formed by etching for the first electrode and the second electrode, in which case an organic solvent is used. The washing process is repeated many times, but the inorganic porous solid thin film is not deteriorated.
[0058]
Moreover, in the said embodiment, although the 1st electrode was formed with ITO and the 2nd electrode was formed as a metal electrode, metal electrodes, such as chromium, are formed on a board | substrate, an organic EL layer is formed in the upper layer, and the last In the case of forming a transparent electrode pattern such as an ITO electrode pattern by vacuum evaporation, the inorganic porous solid thin film according to the embodiment of the present invention is interposed between the transparent electrode pattern and the passivation film covering the upper layer. It may be.
[0059]
The manufacturing method of the organic EL element according to the present invention is not limited to the one exemplified in the above embodiment. For example, in the above embodiment, the organic EL layer is formed in a vacuum, but the organic EL layer may be formed in a nitrogen atmosphere. That is, the ITO transparent electrode and the upper electrode are formed in a vacuum, the organic EL layer is formed in a nitrogen atmosphere, and then sealing is performed in the nitrogen atmosphere. In this case, the organic EL layer may be formed by spin coating.
[0060]
Embodiment 2
In the first embodiment, the formation of the inorganic porous solid thin film, that is, the mesoporous silica thin film formed on the surface of the translucent substrate is performed by immersing in the precursor solution. However, it is limited to the immersion. Alternatively, as shown in FIG. 6, a dip coating method may be used.
[0061]
That is, the substrate is lowered vertically at a speed of 1 mm / s to 10 m / s with respect to the liquid surface of the adjusted precursor solution, and is submerged in the solution, and is allowed to stand for 1 second to 1 hour.
[0062]
Then, after the desired time has elapsed, the substrate is again lifted vertically from the solution at a speed of 1 mm / s to 10 m / s.
[0063]
Finally, as in the first embodiment, by firing, the surfactant is completely pyrolyzed and removed to form a pure mesoporous silica thin film.
[0064]
Embodiment 3
In the first embodiment, the mesoporous silica thin film is formed by dipping in the precursor solution. However, the present invention is not limited to dipping, and as shown in FIG. Good.
[0065]
The precursor solution formed in the same manner as in the above embodiment is dropped onto the surface of the substrate to be processed placed on the spinner and rotated at 500 to 5000 rpm to obtain a mesoporous silica thin film.
[0066]
Finally, as in the first embodiment, by firing, the surfactant is completely pyrolyzed and removed to form a pure mesoporous silica thin film.
[0067]
According to such a configuration, since it has a periodic porous structure, it is possible to increase mechanical strength and to obtain a highly reliable low refractive index film. In addition, since the holes are oriented so as to be parallel to the substrate surface, it has a low refractive index uniformly in the direction perpendicular to the substrate surface, and it is possible to improve the light emission efficiency. In addition, it plays a role as an effective low dielectric constant thin film having excellent moisture resistance and high reliability.
[0068]
Embodiment 4
In the above-described embodiment, an insulating film in which a plurality of periodic porous structure domains including columnar vacancies oriented in one direction are included and adjacent porous structure domains are oriented in different directions has been described. However, as shown in FIG. 8, the holes h may be formed in the same direction over the entire substrate surface.
[0069]
Embodiment 5
Furthermore, as shown in FIG. 9 (f), a structure in which the holes h are oriented in layers is also effective. Here, it is formed by further increasing the concentration of the surfactant in the precursor solution, and the other steps are the same as those in the first to fourth embodiments.
[0070]
When the concentration of the surfactant is further increased in the structure shown in FIG. 5 (c), the molecules are oriented in layers as shown in FIG. 9 (e), and the holes h as shown in FIG. 9 (f) are formed. A low dielectric constant insulating film formed in a layered manner is formed. This structure has a higher porosity and a lower dielectric constant than those having cylindrical holes.
[0071]
In addition, when forming a precursor solution, it turns out that the structure of the structure obtained changes with the ratio of surfactant and a silica derivative.
For example, it is known that when the molecular ratio of a surfactant such as CATB / TEOS and a silica derivative is 0.3 to 0.8, a three-dimensional network structure (cubic) is obtained. When this molecular ratio is smaller than 0.1 to 0.5, a low dielectric constant insulating film in which cylindrical vacancies are oriented is obtained, while larger than this molecular ratio and 0.5 to 2 Sometimes it becomes a low dielectric constant insulating film in which layered holes are oriented.
[0072]
Embodiment 6
Furthermore, as shown in FIG. 10, a structure in which a domain having a structure in which vacancies h are aligned in a layered manner and a domain in which columnar vacancies are aligned is also effective. Here, it is formed by further increasing the concentration of the surfactant in the precursor solution, and the other steps are the same as those in the first to fifth embodiments.
[0073]
In the above embodiment, the application method using a spinner has been described. However, a so-called brush application method in which application is performed with a brush is also applicable.
[0074]
The translucent substrate may be a flexible substrate such as a polyimide tape.
[0075]
When the translucent substrate is a flexible substrate, the mechanical strength and supportability of the film formed in the upper layer are particularly serious problems. According to such a configuration, the mechanical strength is good and the substrate is in close contact with the substrate. Therefore, it is possible to obtain a highly reliable organic EL element.
[0076]
The present invention is also effective when the organic EL element and its drive circuit are formed on the same substrate. The drive circuit section may be formed on a semiconductor layer formed on the inorganic porous solid thin film, or the inorganic porous solid thin film may be used as an interlayer insulating film in the drive circuit section.
According to such a configuration, the above-mentioned organic EL element part with improved luminous efficiency can be formed on the same substrate, and the same inorganic porous solid thin film is used as the low dielectric constant thin film, Since it is formed, it is possible to obtain an organic EL device that has high adhesion to each part, can be driven at high speed, and has high reliability.
[0077]
Even if the chip element is used as an active element and this inorganic porous solid thin film is mounted on the contact formed in the wiring portion of the multilayer wiring structure using the interlayer insulating film, an insulating film having a low dielectric constant is formed. It can be fast and reliable.
[0078]
【The invention's effect】
As described above, according to the present invention, an inorganic porous solid thin film having a porosity of 50% or more is interposed between the translucent substrate and the translucent first electrode. An organic EL element with high controllability, high luminous efficiency and high mechanical strength can be formed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an organic EL device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a light emission principle of the organic EL element.
FIG. 3 is an explanatory diagram showing a process of forming an organic EL element in the first embodiment of the present invention.
FIG. 4 is a diagram showing a process of forming an inorganic porous solid thin film in the first embodiment of the present invention.
FIG. 5 is an explanatory view showing the principle of forming an inorganic porous solid thin film in the first embodiment of the present invention.
FIG. 6 is an explanatory diagram showing a process of forming an inorganic porous solid thin film in the second embodiment of the present invention.
FIG. 7 is an explanatory view showing a process of forming an inorganic porous solid thin film in the third embodiment of the present invention.
FIG. 8 is an explanatory diagram showing a low refractive index film according to a fourth embodiment of the present invention.
FIG. 9 is an explanatory view showing a low refractive index film according to a fifth embodiment of the present invention.
FIG. 10 is an explanatory diagram showing a low refractive index film according to a sixth embodiment of the present invention.
FIG. 11 is an explanatory diagram of a main part of an EL display panel.
FIG. 12 is a diagram showing a conventional organic EL element.
[Explanation of symbols]
h Hole
1 Translucent substrate
2 Inorganic porous solid thin film
3 Translucent first electrode
4 Organic EL layers
h Hole

Claims (12)

A translucent substrate;
An inorganic porous solid thin film formed on the surface of the translucent substrate, the pores having orientation, and a porosity of 50% or more;
A translucent first electrode formed on the inorganic porous solid thin film; an organic EL layer formed on the transparent first electrode;
An organic EL device comprising: a second electrode formed on the organic EL layer. The organic EL element according to claim 1, wherein the inorganic porous solid thin film is configured so that a refractive index is smaller than a refractive index of the translucent substrate. The inorganic porous solid thin film has a periodic porous structure including cylindrical holes formed on a substrate surface and oriented so as to be parallel to the substrate surface. 3. The organic EL device according to 1 or 2. The inorganic porous solid thin film includes a plurality of periodic porous structure domains that are formed on a substrate surface and include cylindrical pores oriented in one direction so as to be parallel to the substrate surface. The organic EL device according to claim 1, wherein the porous structure domains are oriented in different directions. The inorganic porous solid thin film comprises a periodic porous structure domain formed on a substrate surface and having layered pores periodically oriented in one direction so as to be parallel to the substrate surface. The organic EL device according to claim 1, wherein the organic EL device is characterized in that 6. The organic EL element according to claim 1, wherein the translucent substrate is a flexible substrate. A translucent substrate;
An inorganic porous solid thin film formed on the surface of the translucent substrate, the pores having orientation, and a porosity of 50% or more;
An organic EL element portion formed on the inorganic porous solid thin film;
Comprising a drive element portion formed on the inorganic porous solid thin film,
The organic EL element part is
A strip-shaped translucent first electrode formed at a predetermined interval on the inorganic porous solid thin film; an organic EL layer formed on the transparent first electrode;
A strip-shaped second electrode formed on the organic EL layer and formed at a predetermined interval in a direction orthogonal to the first electrode, and constituting a plurality of organic EL elements,
The organic EL device is characterized in that the drive element section is formed on the inorganic porous solid thin film and is connected to the organic EL element section on or below the inorganic porous solid thin film. Forming an inorganic porous solid thin film on a translucent substrate;
Forming a lower electrode on the inorganic porous solid thin film;
Forming an organic EL layer on the lower electrode;
Forming an upper electrode on the organic EL layer,
Forming the inorganic porous solid thin film,
Producing a precursor solution comprising a silica derivative and a surfactant;
Contacting the precursor solution with the substrate surface;
Before or after the contacting step, the precursor solution is heated to start a crosslinking reaction;
A step of baking the light-transmitting substrate contacted with the precursor solution that has been subjected to a crosslinking reaction in the preliminary crosslinking step, and decomposing and removing the surfactant. Production method. The method of manufacturing an organic EL element according to claim 8, wherein the contacting step is a step of immersing the substrate in a precursor solution. 9. The method of manufacturing an organic EL element according to claim 8, wherein the contacting step is a step of immersing the substrate in the precursor solution and pulling it up at a desired rate. The method of manufacturing an organic EL element according to claim 8, wherein the contacting step is a step of applying a precursor solution onto a substrate. The method of manufacturing an organic EL element according to claim 11, wherein the contacting step is a spin coating step in which the precursor solution is dropped on the substrate and the substrate is rotated.

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