JP2003216061A - Composite thin film holding substrate, transparent conductive film holding substrate and vertical cavity surface-emitting body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite thin film holding substrate with high efficiency of taking light outside. <P>SOLUTION: The composite thin film holding substrate includes a composite thin film 4 consisting of a filler 2 having a refractive index lower than that of a base material 1 and a binder 3 having a refractive index higher than that of the filler 2 on the surface of the base material 1. Light is efficiently scattered in passing through the composite thin film 4 consisting of the filler 2 and the binder 3 having different refractive indexes. Moreover, the composite thin film 4 containing the filler 2 having a low refractive index has a low refractive index. As a result, the light passing through the composite thin film 4 can be emitted to the outside from the base material 1 with high efficiency. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light emitter used for various displays, display devices, liquid crystal backlights, and the like, a composite thin film holding substrate and a transparent conductive film holding substrate for the surface light emitter.

[0002]

2. Description of the Related Art In recent years, various displays have been developed with the progress of information-oriented society. One of the typical thin film type light emitting devices used in such a display is, for example, organic electroluminescence (EL).
There is a luminous body.

FIG. 7 shows a light emitting element 15 on a transparent substrate 1.
The structure of the organic electroluminescence light-emitting body formed by providing is schematically shown in a sectional view. The light emitted from the light emitting element 15 is extracted through the base material 1 by being emitted from the exposed surface of the base material 1. As shown by the arrow in FIG. 7, a part of the light that is incident on the interface between the surface of the base material 1 and the air at a small incident angle is reflected by the base material 1.
Most of the light is emitted from the exposed surface of the substrate 1
Is reflected at the interface between the exposed surface of the substrate and air, and is guided in the direction toward the edge of the substrate in the base material 1.
Only about 20% of the emitted light goes out from the exposed surface of the substrate 1. This phenomenon is one of the main causes for keeping the extraction efficiency of the thin film type light emitting device low.

Therefore, avoiding such a phenomenon, the substrate 1
Various measures have been taken to increase the light extraction efficiency from the exposed surface of the. For example, as schematically shown in a sectional view in FIG. 8, the exposed surface of the base material 1 is subjected to fine processing to form a diffusion layer 16, and the diffusion layer 16 of the base material 1 diffuses light. , To reduce the waveguiding in the substrate 1,
The efficiency of extracting light from the exposed surface of the base material 1 to the outside is improved. This fine processing includes microlens processing and diffusion processing.

However, in the case of FIG. 8, since the thickness of the base material 1 is generally on the order of millimeters, the number of times the light in the wave guide hits the diffusion layer 16 is small, and the wave guide is suppressed to improve the extraction efficiency. The effect is not sufficient. Further, since the diffusion layer 16 diffuses the light, when the light emission needs to be recognized as an image as in a display or the like, the light is mixed and it becomes difficult to obtain a clear contrast. There is also the problem of.

In another embodiment, as schematically shown in a sectional view in FIG. 9, a low refractive index layer 17 having a refractive index smaller than that of the base material 1 (for example, a refractive index) is provided between the base material 1 and the light emitting element 15. Is 1.3
The following) is provided. By doing so, light is refracted at the interface between the low refractive index layer 17 and the base material 1, and the incident angle of the light incident on the interface between the exposed surface of the base material 1 and the air becomes small. The amount of light reflected at the interface between the exposed surface of the material 1 and air is reduced, and the waveguiding in the base material 1 is suppressed,
The efficiency of extracting light from the surface of the base material 1 to the outside is improved.

In the case of FIG. 9, by inserting the low refractive index layer 17, it is possible to substantially eliminate the waveguiding in the base material 1, and as a result, it is possible to improve the light extraction efficiency. However, when the thickness of the light emitting element 15 having a refractive index higher than that of the low refractive index layer 17 is large, reflection of light at the interface between the light emitting element 15 and the low refractive index layer 17 increases, and the light emitting element 15 There is a possibility that the number of waveguides in the inside may increase, and there is a problem that the thickness design of the light emitting element 15 needs to be devised.

As described above, in the thin film type light emitting device, it is difficult to improve the extraction efficiency when the emitted light is extracted to the outside (in the atmosphere), and the improvement of the extraction efficiency is a problem.

In general, the extraction rate η at which light generated inside a light-emitting body having a surface-emitting element is extracted to the outside of the light-emitting body is based on the law of classical optics in a medium having a refractive index n. Is determined by the critical angle θc of total reflection when the light is emitted into the air having a refractive index of 1.0.

From the law of refraction, this critical angle θc is given by the following equation (1).

Sin θc = 1 / n (1) Then, the extraction rate η is determined by the amount of light passing through the medium having the refractive index n into the air and the total amount of light generated (the amount of light totally reflected at the interface between the medium and the air and the amount in the air). (Sum of the amount of light passing through) is calculated by the following equation (2).

Η = 1− (n ² −1) ^1/2 / n (2) When the refractive index n of the medium is larger than 1.5, the following approximate expression (3) can be used. Is the refractive index n of the medium
When is extremely close to 1.00, it is necessary to use the above equation (2).

Η = 1 / (2n ² ) (3) Here, in a thin film type light emitting body such as an electroluminescence (EL) element, since the thickness of the surface light emitting element portion is smaller than the wavelength of light, the refraction of the base material The rate mainly controls the extraction rate η. Usually, the refractive index n of glass, plastic film, etc. used as a substrate is 1.5.
It is about 1.6. Therefore, from equation (3), the extraction rate η
Is about 0.2 (about 20%). That is, the remaining 80%
Is lost as guided light due to total internal reflection at the interface between the substrate and air.

An organic EL element is typically used as a thin-film light-emitting body, but the same applies to a PL light-emitting element using a PL (photoluminescence) light-emitting layer as a light-emitting body.
In a PL light emitting element, a PL light emitting layer is formed in a structure laminated on a base material. In this element, when the PL light emitting layer is irradiated with light such as ultraviolet rays, the PL light emitting layer emits light and the light is emitted from the base material. In this element as well, since the light-emitting body is usually formed on the base material, the extraction rate η is low and most of the light is lost as guided light.

In view of the above, Patent Document 1 discloses that a light emitting body is formed on a substrate having a surface layer having a low refractive index.
It is disclosed that the light guide loss at the base material is reduced.
There, a thin film light emitter is formed on a thin film having a low refractive index to improve the light extraction efficiency. In a light emitter whose thickness is smaller than the wavelength of light, the amount of light that can be emitted to the surface of the light emitting layer increases because the waveguiding within the light emitting layer is limited. Specifically, the light emitting layer (organic E
In the case of L, the thickness of the transparent conductive film is 200).
The phenomenon of the limitation of the waveguiding becomes remarkable when the thickness becomes about nm or less. This is because the Applied Physics Letter
s, Volume 78, No. 13, p. 1927 and the like.

Considering the above contents, when a certain light emitting layer is formed on the surface of a base material to form a light emitting body, it is better to form it on a base material having a surface layer having a low refractive index. It is clear that the extraction efficiency is high, and the following formula (4): n2 <n1 (4) (wherein, n1 is the refractive index of the base material, and n2 is previously formed on the base material surface on the light emitting layer formation side). It is advantageous for forming a light-emitting body to form a thin-film surface layer on the base material that satisfies the above relationship of the low refractive index of the surface layer. Generally, a glass or plastic film is used as the substrate,
Its refractive index is about 1.5 to 1.6.

It can be said that there are practically infinite combinations of the types of base materials and the types of thin films provided on the surfaces thereof that satisfy the relationship of the formula (4). Actually, by appropriately selecting the refractive index of the light emitting layer itself, the conditions for forming the light emitting layer (eg temperature, process), etc. Can be improved. In Patent Document 1, it is assumed that a general substrate is used, and the surface thereof has a refractive index of 1.003.
It is proposed to provide a thin film of ˜1.300, and specifically, a porous thin film represented by silica airgel is formed. However, the thin film having a low refractive index formed here is not necessarily strong enough because it is porous.

[0018]

[Patent Document 1] Japanese Patent Laid-Open No. 2001-202827

[0019]

Therefore, by forming a thin film on the surface of the base material regardless of the type of the base material,
There is a demand for a thin layer that can be expected to have an effect of improving luminous efficiency as compared with the above-mentioned known techniques, and preferably has sufficient strength and handleability for forming a luminous body.

Therefore, the present invention comprises a substrate having a higher efficiency of extracting light to the outside than a conventional substrate having a thin layer, more specifically, a substrate having a composite thin film, and a substrate using such a substrate. An object of the present invention is to provide a transparent conductive film holding substrate and a surface light emitting body.

[0021]

The above object is a composite thin film holding substrate comprising a substrate and a composite thin film disposed on the surface thereof, the composite thin film including a filler and a binder. One of the refractive index (Nf) of the filler and the refractive index (Nb) of the binder is
It has been found to be achieved by a composite thin film holding substrate characterized by being smaller than s). Refractive index of filler (N
The other of f) and the refractive index (Nb) of the binder is smaller than this one.

Therefore, in the composite thin film holding substrate of the present invention, the relationship of the refractive index has the following two cases A and B: Case A: Nf <Ns and Nf <Nb Case B: Nb <Ns and Nb <Nf Further, as a result of repeated studies by the inventors, a composite thin film holding substrate comprising a base material and a composite thin film arranged on the surface thereof, wherein the composite thin film comprises a filler and a binder, It has also been found to be achieved by a composite thin film holding substrate, characterized in that both the refractive index (Nf) and the refractive index (Nb) of the binder are higher than the refractive index (Ns) of the substrate.

Therefore, in the composite thin film holding substrate of the present invention, the refractive index relationship satisfies the following case C: Case C: Ns <Nb and Ns <Nf In the present invention, the composite thin film is a filler and a binder. A coating film is formed by applying a liquid coating material composition containing a forming material to a substrate to form a coating film, and drying the coating film to leave the coating film on the substrate. Drying means removing a liquid component (or a volatile component) from the coating film to leave a solid coating film, and may be heated as necessary during drying. In addition, after drying and obtaining a film, you may heat a film and heat-process, and you may heat-process a film by continuing heating at the time of drying.

In the composite thin film, the filler is dispersed in the binder formed from the binder-forming material, and these form different phases from each other. In this sense, the term "composite" is used. The binder holds and holds the filler in a dispersed state in the binder. The binder is formed from the binder-forming material by drying the coating material composition in the form of a film, and during this drying, even if the binder-forming material is chemically changed,
Alternatively, it does not have to change, but it is converted into a solid in the form of a layer as a whole from the state of being dissolved and / or dispersed in the coating material composition. The coating material composition is usually a liquid solvent and / or a dispersion medium (for example, water, alcohol (for example, methanol, ethanol, isopropyl alcohol, etc.), toluene, xylene in order to make it into a liquid state that can be applied to a substrate. Organic solvent such as methyl ethyl ketone), and optionally other components. As such other components, a leveling agent for forming a smooth coating film represented by an acrylic polymer, ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol derivatives such as ethylene glycol monoethyl ether acetate, Examples thereof include thickeners for controlling the film thickness represented by diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether, high boiling point solvents, and silane coupling agents for imparting adhesion to a substrate.

In the composite thin film holding substrate of the present invention, the refractive index (Nf) of the filler and the refractive index (Nb) of the binder.
Both are preferably smaller than the refractive index (Ns) of the substrate, but at least one of the refractive index (Nf) of the filler and the refractive index (Nb) of the binder is the same as the refractive index (Ns) of the substrate. Or it may be larger.

Therefore, the present invention provides, in the first summary,
Providing a composite thin film holding substrate of case A, that is, a composite thin film holding substrate comprising a substrate and a composite thin film disposed on the surface thereof, wherein the composite thin film comprises a filler and a binder. The refractive index (Nf) of the agent is smaller than the refractive index (Nb) of the binder, and the refractive index (Nf) of the substrate is
s) smaller than the composite thin film holding substrate.

In the first aspect, the filler is preferably at least one selected from airgel fine particles, hollow silica fine particles and polymer hollow fine particles, and the binder is selected from organic polymers and metal oxides. It is preferable that it is at least one kind.

Therefore, the present invention provides, in a second aspect,
Case B provides a composite thin film holding substrate, ie a composite thin film holding substrate comprising a substrate and a composite thin film disposed on the surface thereof, the composite thin film comprising a filler and a binder. Has a smaller refractive index (Nb) than the filler (Nf) and has a refractive index (Nb) of the base material.
s) smaller than the composite thin film holding substrate.

In the second aspect, the binder is preferably a silica porous material, for example, the silicone resin-M described later (if it is polycondensable, it may be its polycondensation product), It is preferably an aerogel or the like, and the filler is preferably at least one kind of fine particles selected from organic polymer fine particles, metal compound fine particles and hollow silica fine particles.

Therefore, the present invention provides, in a third aspect,
Providing a composite thin film holding substrate of case C, namely a composite thin film holding substrate comprising a substrate and a composite thin film disposed on the surface thereof, the composite thin film comprising a filler and a binder. Provided is a composite thin film holding substrate in which both the refractive index (Nf) of the agent and the refractive index (Nb) of the binder are higher than the refractive index (Ns) of the base material.

In the third aspect, the binder is preferably an organic polymer or a metal oxide having a refractive index of 1.8 or less, such as an acrylic polymer or silica / titania composite oxide described below, and a filler. Is also at least 1 selected from organic polymer particles and metal compounds.
It is preferably a fine particle of a seed. Further, in the third aspect, the mixing ratio of the binder and the filler in the coating composition needs to be appropriately adjusted to a necessary ratio, and in the obtained composite thin film, the solid content in the composite film is adjusted. The volume ratio is adjusted to 75% or less.

In the first aspect, the refractive index of the filler having a lower refractive index than that of the substrate is generally 1.35.
In the second aspect, the binder having a refractive index lower than that of the base material generally has a refractive index of 1.45 or less, preferably 1.30 or less. Is preferably 1.30 or less.
Further, in the third aspect, it is desirable that the binder having a refractive index higher than that of the substrate has a refractive index of generally 1.8 or less, preferably 1.6 or less.
In any case, the refractive index of the composite thin film is usually 1.4 or less, preferably 1.35 or less.

In a fourth aspect, the present invention provides a transparent conductive film holding substrate, wherein a transparent conductive film is formed on the composite thin film of the above-mentioned composite thin film holding substrate of the present invention. There is. In this transparent conductive film holding substrate, a very thin smoothing underlayer (for example, having a thickness of about 10 to 100 nm) is formed on the composite thin film, and the transparent conductive film is formed on the smoothing underlayer. You may

In a fifth aspect, the present invention provides a surface light emitter which is excited by ultraviolet rays or electron beams on the composite thin film of the above-mentioned composite thin film holding substrate of the present invention. A thin film of an organic or inorganic phosphor that emits light is formed.

In a sixth aspect, the present invention provides another surface light-emitting body, which is provided on the transparent conductive film of the transparent conductive film holding substrate of the present invention described above. The light emitting layer and the metal electrode 9 are laminated in this order to form an electroluminescent element.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

In the composite thin layer holding substrate of the present invention, the base material can be used without particular limitation as long as it is translucent, and is usually in the form of a sheet or plate. The substrate may be, for example, a transparent glass plate, a transparent plastic plate or the like, and is not particularly limited as long as it is generally used as a translucent plate. In most cases, the refractive index of the base material 1 is in the range of 1.46 to 1.6.

In the composite thin layer holding substrate of the present invention, examples of the material which can be used as the filler include airgel fine particles, hollow silica fine particles, polymer hollow fine particles, organic polymer fine particles and metal oxide fine particles. In addition, examples of materials that can be used as the binder include organic polymers, metal oxides, and silica porous materials (particularly the silicone resin described below).
M, silica airgel, etc.) and the like. From these usable materials, the combination of the filler and the binder may be selected so as to satisfy the above-mentioned relationship of the refractive index. Next, the filler and the binder will be described.

Unless otherwise specified, in this specification, the refractive index means the refractive index obtained as follows: (Refractive index of filler) Regarding the refractive index of the filler, the filler is Whether the fine particles as a solid body, a porous body, or a hollow body (including the case where the outer shell is porous) can be determined as follows.

The refractive index and specific gravity of a sol in which a filler is dispersed in a solvent typified by water or alcohol are measured, and the refractive index and specific gravity of the solvent constituting the sol and the substance forming the filler are measured. Calculated by the following formula using true specific gravity and refractive index: n = n ₀ (PN ₀ −P ₀ N) / {n ₀ (P−P ₀ ) + p ₀ (where refractive index −1 of the filler is n) N
_0- N)} is established, and the refractive index of the filler is n + 1.

In the above formula, symbols are as shown below, and the formula is derived from the following formulas (a), (b) and (c).

The expressions (a) and (b) are expressions showing the relationship between the refractive index and the specific gravity of a mixture obtained by uniformly mixing two substances, and these are obvious to those skilled in the art. is there. On the other hand, for a filler as a porous body having fine voids whose size (generally diameter) is submicron level or less, the refractive index of the porous body is such that the solid part and void part of the porous body have Determined by the volume ratio, the refractive index of the porous body and the solid filling rate in the porous body (ie, 1
-Porosity of porous body), [refractive index of porous body-
It is generally known that 1] is proportional to the solid filling rate. Based on this, the true specific gravity (p ₀ ) of the substance forming the porous body and the original refractive index −1 of the substance (refractive index −1: n _{0 of} the solid pure substance forming the porous body) When,
From the bulk specific gravity (p) of the porous body, the formula for calculating [refractive index of porous body-1], that is, n is (c), which is also well known to those skilled in the art. Incidentally, the formula (c) is a formula which is originally applied to the filler of the porous body, but it can be similarly applied to the fine particles of the hollow body (including the case where the outer shell is porous). By setting the true specific gravity and the bulk specific gravity to be the same and the refractive index of the filler to be the same as the refractive index of the substance constituting the filler, the formula (c) can be applied even if the filler is a solid substance. Needless to say, the refractive index of the filler can be obtained by the above formula.

Refractive index of sol (measured value) = N + 1 Refractive index of solvent = N ₀ +1 Refractive index of substance constituting filler = n ₀ +1 Specific gravity of sol (measured value) = P Specific gravity of solvent = P ₀ filling True specific gravity of substances constituting the agent = p ₀ Bulk specific gravity of the filler = p Occupied volume ratio of the filler in the sol = V V = (N−N ₀ ) / (n−N ₀ ) (a) V = ( P−P ₀ ) / (p−P ₀ ) (b) n = pn ₀ / p ₀ (c) (refractive index of binder) The refractive index measured by ellipsometry of the coating film obtained as follows. The binder-forming material is dissolved and / or dispersed in a suitable solvent (eg, alcohol such as methanol or isopropyl alcohol) to obtain a liquid mixture, which is applied to a substrate to obtain a coating film. Remove liquid (or volatile matter) and dry Coating that remains on the substrate by. It should be noted that this coating constitutes a binder portion in the composite coating of the present invention.

(1-1) Airgel Fine Particles as Filler As the airgel fine particles, for example, silica airgel fine particles, composite airgel fine particles such as silica / alumina airgel, organic airgel fine particles such as melamine aerogel, and the like can be used. Silica airgel is disclosed in, for example, US Pat. Nos. 4,402,827 and 4,432.
As described in Japanese Patent Publication No. 956 and Japanese Patent Publication No. 4610863, a gel state in a wet state composed of a silica skeleton obtained by hydrolysis and polycondensation reaction of alkoxysilane (also referred to as silicon alkoxide or alkyl silicate). The compound can be produced by dispersing the compound in a solvent (dispersion medium) such as alcohol or carbon dioxide and drying it in a supercritical state at or above the critical point of this solvent. Supercritical drying, for example, by immersing the gel-like compound in liquefied carbon dioxide, replace all or part of the solvent that the gel-like compound previously contained with liquefied carbon dioxide having a lower critical point than the solvent, Then, it can be performed by drying under supercritical conditions of carbon dioxide alone or a mixture of carbon dioxide and a solvent.

Alternatively, silica airgel can be prepared according to US Pat. Nos. 5,137,279 and 5,12,436.
As described in Japanese Patent Publication No. 4, it can be produced in the same manner as above using sodium silicate as a raw material.

In producing silica airgel, JP-A-5-279011 and JP-A-7-1383.
As disclosed in JP-A-75, by hydrophobizing the gel-like compound obtained as described above by hydrolysis and polycondensation reaction of alkoxysilane,
It is preferable to impart hydrophobicity to the silica airgel.
The hydrophobic silica aerogel thus imparted with hydrophobicity can prevent moisture, water, and the like from infiltrating thereinto easily, and prevent the silica aerogel from deteriorating its performance such as refractive index and light transmittance. This step of hydrophobizing treatment can be carried out before or during supercritical drying of the gel compound.

The hydrophobizing treatment is carried out by reacting the hydroxyl group of the silanol group present on the surface of the gel-like compound with the functional group of the hydrophobizing agent to replace the silanol group with the hydrophobic group of the hydrophobizing agent. As a method for performing the hydrophobizing treatment, for example, the gel is immersed in a hydrophobizing treatment solution in which a hydrophobizing treatment agent is dissolved in a solvent, and the hydrophobizing treatment agent is allowed to penetrate into the gel by mixing, etc. Accordingly, there is a method of heating to cause the hydrophobization reaction. Examples of the solvent used for the hydrophobic treatment include methanol, ethanol, isopropanol, xylene, toluene, benzene, N, N-.
Examples thereof include dimethylformamide and hexamethyldisiloxane. The solvent is not limited to these as long as the hydrophobic treatment agent can be easily dissolved and can be replaced with the solvent contained in the gel before the hydrophobic treatment.

When supercritical drying is performed in the step after the hydrophobizing treatment, is the solvent used for the hydrophobizing treatment an easy supercritical drying medium (eg, methanol, ethanol, isopropanol, liquid carbon dioxide, etc.)? , Or those substitutable for it are preferable. Examples of the hydrophobic treatment agent include hexamethyldisilazane, hexamethyldisiloxane, trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, trimethylethoxysilane, dimethyldiethoxysilane, methyltriethoxysilane, etc. Can be mentioned.

In the present invention, the airgel fine particles used as the filler can be obtained, for example, by pulverizing the silica airgel previously prepared as described above. Alternatively, it can be obtained by pulverizing the wet gel before drying and then drying. In the case where sodium silicate is used as a starting material, airgel particles can be obtained by atomizing during suspension polymerization. The refractive index of the silica aerogel obtained as described above can be set to a desired value by variously selecting the type and mixing ratio of raw materials used for producing the silica aerogel.

(1-2) Hollow silica fine particles as a filler As the hollow silica fine particles which can be used as a filler, a hollow silica sol produced by the method described in JP-A No. 2001-233611, which is generally commercially available. Other known hollow silica powders can be used. Throughout the present specification, hollow fine particles are fine particles having a cavity surrounded by an outer shell, and any suitable known hollow silica fine particles may be used. The outer shell of the hollow silica fine particles is made of a silica-based inorganic oxide. Particularly preferable hollow silica fine particles to be used are, for example, as follows: The outer shell of the silica-based inorganic oxide is (A) a single layer of silica, (B) silica and other than silica. It includes a single layer of a composite oxide composed of an inorganic oxide, and (C) a double layer of the (A) layer and the (B) layer. The outer shell may be porous having pores, or may be one in which the pores are closed and the cavity is sealed to the outside of the outer shell. The outer shell is preferably a plurality of silica-based coating layers including an inner first silica coating layer and an outer second silica coating layer. By providing the second silica coating layer on the outer side, it is possible to close the fine pores of the outer shell to densify the outer shell, and further to obtain hollow silica fine particles in which the inner cavity is sealed.

The outer shell has a thickness of 1 to 50 nm, especially 5 to 20 nm.
It is preferably in the range of nm. When the thickness of the outer shell is less than 1 nm, the hollow fine particles may not retain a predetermined particle shape. On the other hand, when the thickness of the outer shell exceeds 50 nm, the cavities in the hollow silica fine particles are small, and as a result, the ratio of the cavities is reduced, and the refractive index may not be sufficiently lowered. Furthermore, the thickness of the outer shell is preferably in the range of 1/50 to 1/5 of the average particle diameter of the hollow fine particles. When the first silica coating layer and the second silica coating layer are provided as the outer shell as described above, the total thickness of these layers may be set within the above range of 1 to 50 nm, and in particular, they are densified. The outer shell has a thickness of the second silica coating layer of 20 to
A range of 40 nm is preferred.

The solvent used when the hollow silica fine particles are prepared and / or the gas infiltrating during the drying may be present in the cavity. Further, a precursor substance for forming a cavity described below may remain in the cavity. The precursor material may adhere to the outer shell and remain slightly, or may occupy most of the inside of the cavity. Here, the precursor substance is a porous substance that remains after a part of the constituent components of the core particle is removed from the core particle surrounded by the outer shell. As the core particles, porous composite oxide particles composed of silica and an inorganic oxide other than silica are used. As the inorganic oxide, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO
₂ , SnO ₂ , Ce ₂ O ₃ , P ₂ O ₅ , Sb ₂ O ₃ , M
One or more of oO ₃ , ZnO ₃ , WO _{3 and the} like can be mentioned. TiO as two or more kinds of inorganic oxides
It can be exemplified _{2 -Al 2 O 3, TiO 2} -ZrO 2 or the like. The solvent or gas may be present in the pores of this porous material. When the removal amount of the constituent components of the core particles at this time increases, the volume of the cavities increases, and hollow silica fine particles with a low refractive index are obtained. Excellent prevention performance.

In the present invention, the average particle diameter of the hollow silica fine particles is preferably in the range of 5 nm to 2 μm. 5n
If the average particle size is smaller than m, the effect of lowering the refractive index due to hollowness is small, and if the average particle size is larger than 2 μm, the transparency becomes extremely poor and diffuse reflection (Anti-Gla
re) will make a big contribution. In the present invention, applications in which the composite thin film is required to have high transparency include antireflection applications such as the outermost surface of a display. For that purpose, it is preferable that the hollow silica fine particles used have a particle diameter in the range of 5 to 100 nm. still,
The particle size used in this specification is the number average particle size as observed by a transmission electron microscope.

The method for producing hollow silica fine particles as described above is publicly known as described in detail in JP-A-2001-233611, and a commercially available product produced by this method is provided. A commercially available product can be obtained and used.

The refractive index of the hollow silica fine particles can be set to a desired value by variously adjusting the thickness of the outer shell and the particle diameter of the hollow silica fine particles at the stage of producing the hollow fine particles.

Regarding the hollow silica fine particles, the outer shell may be a dense layer or a porous layer, but it is preferable that the particle diameter and outer shell thickness are uniform. This is because the particle diameter and the volume ratio of the hollow fine particles in the composite thin film determine the refractive index of the composite thin film.

(1-3) Polymer Hollow Fine Particles as Filler As a filler for the composite thin film of the composite thin film holding substrate of the present invention,
Polymer hollow particles can be used. The outer shell of the fine particles is made of a polymer material such as a fluoropolymer. Various such fine particles are disclosed in, for example, Japanese Patent Laid-Open No. 10-142402.
The contents of this patent publication are hereby incorporated by reference. Particularly preferred polymer hollow fine particles to be used are fluorine-based polymers, and the use of this makes it possible to easily reduce the refractive index of the composite thin film.

The refractive index of the polymer hollow fine particles can be set to a desired value by variously selecting the particle diameter and the polymer material.

(1-4) Organic Polymer Fine Particles as Filler As a filler for the composite thin film of the composite thin film holding substrate of the present invention,
Fine particles of organic polymers can be used. Examples of the organic polymer include silicone resin, acrylic resin, styrene resin and the like. Such an organic polymer can be obtained as a filler in the form of fine particles by suspension polymerization, supercritical polymerization, etc., but may be fine particles produced by another method as long as the fine particles can be obtained. The refractive index of the organic polymer fine particles can be set to a desired value by selecting various polymer materials.

(1-5) Metal oxide fine particles as a filler As a filler for the composite thin film of the composite thin film holding substrate of the present invention,
Fine particles of metal oxide can be used. Examples of this metal oxide include titania fine particles, indium tin oxide fine particles, silica fine particles, alumina fine particles, and the like. They are,
A commercially available sol is previously used as a dispersion sol and mixed with the coating material composition. As particularly preferable metal oxide fine particles to be used, when selecting one having a large refractive index, titania fine particles, indium tin oxide fine particles can be exemplified, and when selecting one having a small refractive index,
Silica can be exemplified. The refractive index of the metal oxide fine particles can be set to a desired value by variously selecting the material itself.

(2-1) Organic Polymer as Binder An organic polymer can be used as the binder of the composite thin film of the composite thin film holding substrate of the present invention. This organic polymer is
It may be the same as the polymer forming the organic polymer fine particles described above. Therefore, such a polymer is in a dissolved and / or dispersed state in a liquid coating material composition, and by coating and drying the polymer, a solid film containing a filler in a dispersed state is formed. That is, in this case, the organic polymer itself is the binder-forming material and also the binder. As another example of such a polymer, an acrylic resin, a fluorine resin, or the like having excellent transparency is preferable, but those generally used as an optical thin film coating may be used.

In another embodiment, the binder-forming material may be chemically changed to a binder when the coating film obtained by applying the coating material composition is dried. For example, the binder-forming material may be a reactive (eg, crosslinkable, polycondensable, etc.) organic monomer, organic oligomer, or organic prepolymer that reacts to become an organic polymer as a binder. Good. Therefore, such an organic monomer, organic oligomer or organic prepolymer is dissolved and / or dispersed as a reactive binder forming material in a liquid coating material composition. Such organic monomers, organic oligomers or organic prepolymers which are preferably used include epoxy-based monomers, oligomers,
Examples thereof include prepolymers.

The refractive index of the organic polymer is
A desired value can be obtained by variously selecting the organic monomer, the organic oligomer and the organic prepolymer which bring about it.

(2-2) Silica porous material as binder A silica porous material can be used as the binder of the composite thin film of the composite thin film holding substrate of the present invention. Here, the silica porous material means a material in which silica as a binder for holding the filler in a dispersed state contains a large number of fine voids. Such a silica porous material is preferably used when a silica-based material is used as the filler.

A binder-forming material that can be used to form a particularly preferred porous silica is represented by the general formula (1):

[0066]

[Chemical 1]

(Wherein the substituents X ¹ , X ² , X ³ and X
⁴ is selected from hydrogen, halogen (eg chlorine, fluorine, etc.), a monovalent hydrocarbon group, an alkoxy group represented by OR (R is a monovalent hydrocarbon group) and a hydroxyl group represented by OH. Groups, which may be different from each other, partially different from each other, or all the same, and at least two of them are groups selected from an alkoxy group and a hydroxyl group, respectively. ) Is a silane compound represented by. The silane compound has at least 2, preferably 3, and more preferably 4 the same or different alkoxyl groups and / or hydroxyl groups. The binder-forming material may be one in which at least one alkoxyl group of the silane compound is hydrolyzed.

In another embodiment, the binder-forming material is a siloxane compound or polysiloxane compound formed by condensing one or more of the above silane compounds, if hydrolyzable, if hydrolyzed and then hydrolyzed. . The polysiloxane compound means a compound having two or more siloxane bonds. This (poly) siloxane compound preferably has at least two alkoxy groups and / or hydroxyl groups as substituents.

When the above-mentioned silane compound and (poly) siloxane compound have an alkoxyl group, they can have a hydroxyl group produced by hydrolysis of the alkoxyl group. As a result, these silane compounds and (poly) siloxane compounds can also be condensed and crosslinked at least partially when the coating material composition is applied and dried to form porous silica as a binder.
Even when the (poly) siloxane compound does not have a substituent on the alkoxy group and / or hydroxyl group, a porous binder can be formed when the coating material composition is applied and dried.

A particularly preferred porous silica material is SiX ₄
(X is, for example, a hydrolyzable substituent having 1 to 4 carbon atoms, for example, an alkoxyl group having 1 to 5 carbon atoms),
A polysiloxane compound (in the present specification, this polysiloxane, obtained by polycondensation of a partial or complete hydrolyzate of a tetrafunctional hydrolyzable organosiloxane having four hydrolyzable substituents on elemental silicon. The compound is referred to as “silicone resin-M”), and the coating material composition is used, and the coating film is dried. In addition, in order to distinguish from what is generally known as “silicone resin”, the polysiloxane compound as the binder forming material is referred to as “silicone resin-type” in this specification.
M ”(SILICONE RESIN-M).
Such "silicone resin-M" need not be the same as what is commonly known as a silicone resin. The silicone resin-M may itself have a hydrolyzable substituent, and in that case, when the silicone resin-M forms a binder, it is hydrolyzed and condensed to give a silicone having a higher molecular weight. Form a binder as Resin-M. When the silicone resin-M does not have such a substituent, the silicone resin-M directly forms the binder.

Therefore, a composite thin film in which the filler is dispersed in the binder is prepared by including the binder-forming material as described above together with the filler in the coating material composition, applying it to the substrate and drying the coating film. Obtainable. The refractive index of such a porous silica material as a binder can be set to a desired value by variously changing the weight ratio of the filler and the binder-forming material.

Such a silicone resin-M forming a silica porous material preferably has a weight average molecular weight of about 200 to 2000, and 600 to 1200 when the mechanical strength of the composite coating is required. Is more preferable. A molecular weight in this range tends to easily improve the strength of the composite coating and increase the porosity of the binder (that is, the ratio of voids in the binder). The silicone resin-M preferably has a weight average molecular weight of about 2,000 or more, more preferably 3,000 or more, for example, 3,000 to 5,000, when the composite coating is not required to have high mechanical strength. is there.

The composite coating formed using Silicone Resin-M is preferably 100 to 3 if necessary.
It may be heat-treated at 00 ° C, more preferably at 50 to 150 ° C for 5 to 30 minutes, and the mechanical strength of the composite coating can be improved.

In another embodiment, the porous silica material is silica airgel. The airgel as the binder is coated with a gel-like compound obtained by the hydrolysis / polymerization reaction of the alkoxysilane (silicon alkoxide, particularly the above-mentioned tetrafunctional alkoxysilane) as described above, the gelation reaction of the aqueous sodium silicate solution, and the like. It can be used as a binder-forming material contained in a material composition, by applying a coating material composition to obtain a coating film, and drying the coating material to form a film while holding the filler. Therefore,
In this case, the binder-forming material is an alkoxysilane or a hydrolyzate thereof (not all the alkoxyl groups are necessarily hydrolyzed, and a partial hydrolyzate in which only a part of the alkoxyl groups is hydrolyzed is included). And at least one condensate of a hydrolyzate. In general, the binder-forming material is preferably a condensate of hydrolysates. Such silica airgel can be obtained as described above. By mixing the filler in a wet gel compound and drying the mixture, a composite thin film in which the filler is dispersed in silica airgel can be obtained. Therefore, the coating composition
It comprises a wet gel-like compound and a filler.

The refractive index of such an airgel as a binder can be set to a desired value by selecting the mixing ratio of the raw material solution, the drying method and the like.

(2-3) Metal Oxide as Binder A metal oxide can be used as the binder of the composite thin film of the composite thin film holding substrate of the present invention. In this case, the metal oxide precursor contained as a binder forming material in the coating material composition changes into a metal oxide as a binder when the coating film obtained by applying the coating material composition is dried. Examples of such metal oxide precursors that are preferably used include silica and silica / titania composite oxides. The refractive index of the metal oxide as the binder can be set to a desired value by variously selecting the constituent element species of the substance that provides the metal oxide.

In the composite film holding substrate of the present invention, the combination of the filler and the binder described above may be selected so as to satisfy the above relationship of the refractive index. The refractive index of the composite thin film formed from the combination of such filler and binder (that is, the refractive index of the composite film as a whole)
Is usually smaller than the refractive index theoretically calculated from the refractive index of the filler, the refractive index of the binder, and the filler / binder ratio in the thin film formed. This is because in the binder of the composite thin film to be formed, in addition to voids that may be inherent in the binder material itself (for example, voids due to the porosity of the binder), voids are present between the fine particles constituting the filler. It may be present, and voids may be present between the fine particles of the filler and the binder. In fact, when the filler and the binder-forming material are mixed to form a composite coating, such other Voids are also included in the composite thin film, and such voids have the effect of lowering the refractive index of the composite thin film. In the present specification, the refractive index of the composite thin film means a general refractive index including the effect of such other voids.

In the composite coating film formed by using the coating material composition of the present invention, the binder existing around the filler and acting as a matrix means a state in which a large number of fine voids are contained therein. Therefore, the apparent specific gravity of the binder is smaller than the true specific gravity of the material itself (that is, the material when voids are substantially absent) constituting the binder. The ratio of the apparent specific gravity of the binder to the true specific gravity of the binder is preferably 0.90 or less, more preferably 0.75 or less, for example 0.50 to 0.75. In addition, this ratio is a value calculated including the volume of such voids when the composite coating film includes the above-mentioned "other voids". The voids in the binder usually contain the gas around the coating.

In one example, a tetrafunctional silicone resin (ie, Silicone Resin-M) as a binder with a refractive index of 1.45 and hollow silica particles as a filler with a refractive index of 1.32 were used as a binder / filler. Volume ratio 0.1
.About.0.3, the average refractive index of the composite thin film is 1.26 to 1.
Can be 35.

In another example, silica airgel as a binder with a refractive index of 1.20 and acrylic polymer microparticles as a filler with a refractive index of 1.59 are used in a binder / filler volume ratio of 0.5 to 0.75. The average refractive index of the composite thin film containing the same can be 1.30 to 1.40.

In yet another example, a refractive index of 1.5
No. 9 acrylic polymer as a binder and silica / titania composite oxide fine particles as a filler having a refractive index of 1.6, and a binder / filler volume ratio of 0.05 to 0.1.
The composite thin film containing 5 may have an average refractive index of 1.35 to 1.40. In the case of this composite thin film, when calculated on the basis of the apparent volume of the composite coating and the weight of the binder and the filler, about 40% of the volume of the composite thin film is occupied by the voids, and therefore the composite thin film The average refractive index is smaller than that of the filler and smaller than that of the binder.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1A is a sectional view schematically showing one form of the composite thin film holding substrate A of the first aspect. In the illustrated form, the filler 2 and the binder 3 are formed on the surface of the substrate 1.
The composite thin film 4 is formed. The composite thin film 4 is obtained by applying a liquid coating material composition, which is a mixture of a filler and a binder forming material, onto the base material 1 and drying it. In the illustrated embodiment, the refractive index of this filler 2 is lower than that of the base material 1, and the refractive index of the formed binder 3 is higher than that of the filler 2. The base material 1 is as described above.

The refractive index of the filler 2 is not particularly limited as long as it is lower than that of the base material 1, but is usually lower than 1.35, preferably lower than 1.3. The refractive index is desirable in order to reduce the average refractive index of the composite thin film 4. Since the lower the refractive index of the filler 2 is, the lower limit is ideally 1.0, but practically 1.003, and the lower limit may be 1.1 in general. The refractive index of the binder is not particularly limited as long as it is higher than the refractive index of the filler, but usually 1.
A refractive index lower than 5, preferably lower than 1.46 is desirable in order to lower the average refractive index of the composite thin film 4.

Examples of the filler 2 having a refractive index lower than that of the base material 1 include the above-mentioned airgel fine particles, hollow silica fine particles, polymer hollow fine particles and the like.

When silica airgel fine particles are used as the airgel fine particles of the filler 2, the refractive index thereof is preferably in the range of 1.008 to 1.18 in order to secure performances such as transparency of the silica airgel. More preferably, it is adjusted to be within the range of 1.1 to 1.3.

When hollow silica fine particles are used as the filler 2, the refractive index thereof is preferably 1.2 to 1.35,
More preferably, it is adjusted to be within the range of 1.2 to 1.3.

When polymer hollow particles are used as the filler 2, the refractive index thereof is preferably 1.2 to 1.
4, more preferably, it is adjusted to be within the range of 1.2 to 1.3.

The filler 2 having a low refractive index described above preferably has a particle size in the range of 5 nm to 2 μm, and particularly 20 n.
It is more preferably m to 500 nm. When the filler is hollow fine particles, the thickness of the outer shell is preferably 5 nm to 20 nm. The smaller the particle size of the filler 2, the higher the effect of lowering the average refractive index of the composite thin film 4 (that is, the refractive index of the composite thin film as a whole), and the composite thin film 4 having excellent transparency can be obtained. As a result, the light extraction efficiency can be increased. On the contrary, the larger the particle size, the greater the scattering effect in the composite thin film 4 and the greater the effect of suppressing the waveguiding of light, so that the light extraction efficiency can be increased. In order to have both of these effects, the particle size of the filler 2 is preferably in the above range, and the particle size of the filler 2 is the refractive index of the binder 3 constituting the composite thin film 4, the type and thickness of the light emitting element, and the like. According to the above, an appropriate one can be appropriately selected within the above range. The particle size described in this specification refers to the primary particle size, and the particle size is measured by visual observation such as observation with a transmission electron microscope.

On the other hand, the binder 3 having a refractive index higher than that of the filler 2 is preferably an organic polymer or metal oxide produced from the binder-forming material contained in the transparent coating material composition. If the refractive index of the binder 3 is higher than that of the filler 2, the binder is a binder such as the above-mentioned organic polymer or metal oxide, and if the refractive index is higher than the refractive index of the filler, the kind thereof is There is no particular limitation. As a material that is preferably used as the binder-forming material, in the case of an organic polymer as a binder, acrylic polymers such as methyl methacrylate, epoxy-based polymers, fluorine-based polymers, styrene-based polymers, etc. can be exemplified, and formed using these. The binder has a refractive index of usually 1.4 to 1.65, preferably 1.45 to 1.6. In addition, as a material which is preferably used as the binder-forming material, in the case of a metal oxide as a binder, silica, indium tin oxide, titania, silica / titania composite oxide, zirconia, etc. can be exemplified. The refractive index of the binder is usually 1.45 to 3.0, preferably 1.45 to 2.5.

In particular, it is desirable to select a binder-forming material having a good dispersibility of the filler 2 used together in the coating material composition. Above all, when a silica-based material is used as the filler 2, SiX ₄ described above is used.
A silicone resin-M obtained by polycondensation of a partial or complete hydrolyzate of a tetrafunctional hydrolyzable organosiloxane represented by (X is an alkoxyl group having 1 to 4 carbon atoms) is used as the binder 3. Is most preferred. As mentioned above, this silicone resin-M
It may itself have hydrolyzable substituents, or Silicone Resin-M may not have such substituents. Thus, the refractive index of the binder 3 formed of the silicone resin-M is usually 1.3 to 1.
50, preferably 1.3 to 1.45.

In the composite thin film 4, the abundance ratio of the filler 2 and the binder 3 varies depending on the ratio of the respective refractive indices and the ratio of the densities, but the mass ratio of the filler 2 is 40 to 95 mass%. Preferably, in that case, the average refractive index of the composite thin film 4 is usually 1.2 to 1.4, preferably 1.20.
It is 1.35. When the ratio of the low refractive index filler 2 is lower than 40% by mass, the average refractive index of the composite thin film 4 becomes large, and when it is higher than 95% by mass, the strength of the composite thin film 4 and the base material 1 are increased. There is a possibility that the practicability becomes insufficient, such as a decrease in the adhesiveness, and both are not preferable.
Throughout the present specification, the average refractive index of the composite coating means the refractive index measured as described in Examples below.

When forming the composite thin film 4 on the surface of the substrate 1, the filler 2 and the binder 3 are mixed with a solvent to dissolve and / or disperse the liquid to prepare a liquid coating material composition. After applying the composition to the surface of the substrate 1, the composition is dried to remove the liquid and leave the film as the composite thin film 4. Upon such drying,
You may heat as needed. Further, the coating film obtained may be fired by further heat treatment if necessary.
As a coating method, any suitable method such as spin coating, dip coating, flow coating, roll coating and bar coating may be adopted. An appropriate coating method can be selected depending on the thickness of the composite thin film 4, the size of the base material 1, the type, and the like.

In the first aspect of the present invention, the average refractive index of the composite thin film formed as described above is generally smaller than the refractive index of the substrate, for example, 0.01 to 0.5, preferably It is desirable that it is smaller by 0.05 to 0.3. The average refractive index itself of the composite thin film is usually 1.2 to 1.4, preferably 1.20 to 1.35, and more preferably 1.
25 to 1.3. However, since the filler 2 can diffuse the light passing through the composite thin film 4, it may be slightly larger than the average refractive index of the composite thin film, for example, 1.35 to 1.4.
It may be as large as 5.

In FIG. 1B, the composite thin film holding substrate A of FIG. 1A is used, and a thin film light emitting element 15 is provided on the side of the composite thin film 4 opposite to the side on which the base material 1 is located. The surface luminous body A is conceptually shown in a sectional view. In the illustrated form, the light emitting element 1
The light emitted at 5 passes through the composite thin film 4 and the base material 1 and is extracted from the surface of the base material 1 as indicated by the arrow. The composite thin film 4 is a composite layer of the filler 2 having a lower refractive index and the binder 3 having a higher refractive index, and the average refractive index of the composite thin film 4 is preferably smaller than that of the substrate 1. The light is diffused in the interface between the light emitting element 15 and the composite thin film 4 and in the composite thin film 4, and passes through the base material 1 as diffused light. At this time, the incident angle of the light incident on the substrate 1 from the composite thin film 4 becomes small,
As a result, it is possible to reduce the amount of light reflected at the interface between the surface of the substrate 1 and the air to reduce the waveguiding within the substrate 1, and in the preferred case, make it almost nonexistent. be able to.

There is also a light component which can be guided in the light emitting element 15, but the interface between the light emitting element 15 and the composite thin film 4 is reduced in flatness as schematically shown by the influence of the filler. As a result, scattering at the interface can reduce this waveguiding. Furthermore, since the thickness of the light emitting element 15 is at most a submicron order (for example, 0.05 to 1 μm),
The guided light hits the interface between the light emitting element 15 and the composite thin film 4 a great number of times, and almost all of the guided light can finally be transmitted to the composite thin film 4 side. Thus, the composite thin film 4 is formed on the substrate 1.
It is possible to reduce the waveguiding of light by providing
The light extraction efficiency from the surface of the base material 1 can be improved.

In this composite thin film 4, the larger the difference in refractive index between the filler 2 and the binder 3, the higher the light extraction efficiency can be. Specifically, this difference is preferably at least 0.01, More preferably at least 0.05
Is. The surface of the composite thin film 4 on which the light emitting element 15 is arranged preferably has a high roughness as long as the light emitting element 15 can be formed.

The particles 2 of the filler in the above composite thin film 4
The space between them does not necessarily have to be completely filled with the binder 3, and a void portion (this can also be referred to as a bubble) may exist between them. The void usually contains a surrounding gas (generally air), and thus the void has a low refractive index like the filler 2, or a lower refractive index. Therefore, the filler 2
If a void remains between the two, the void acts in substantially the same manner as the filler 2, and as a result, the light extraction efficiency is improved. The average refractive index of the composite thin film 4 as a whole is preferably lower than the refractive index of the base material 1, but may be slightly higher than that of the base material 1.

FIG. 2A is a sectional view schematically showing one form of the composite thin film holding substrate A of the second aspect. In the illustrated form, the filler 2 and the binder 3 are formed on the surface of the substrate 1.
The composite thin film 4 is formed. The composite thin film 4 is obtained by applying a coating material composition which is a mixture of the filler 2 and a binder forming material and drying it. In the illustrated embodiment,
The refractive index of the formed binder 3 is lower than that of the base material 1, and the refractive index of the filler 2 is higher than that of the binder 3.

The binder 3 having a refractive index lower than that of the base material 1 is not particularly limited as long as it is translucent and has a refractive index lower than that of the base material 1. Above all, the above-mentioned silica porous body and airgel ( For example, silica airgel) is preferable. To lower the average refractive index of the composite thin film 4,
Generally, it is desirable that the refractive index of the binder 3 is lower than 1.3, preferably lower than 1.25.

When a porous silica material is used as the binder 3, the binder has a refractive index of preferably 1.2 to 1.45, more preferably 1.2 to 1.35. It is preferable to select the forming material.

When an airgel is used as the binder 3, a binder forming material is used so that the refractive index thereof is preferably in the range of 1.005 to 1.3, more preferably in the range of 1.1 to 1.3. It is preferable to select it.

As the filler 2 having a refractive index higher than that of the binder 3, hollow silica fine particles such as fine particles of metal oxides such as silica and titania described above and fine particles of organic polymers typified by silicone are used. it can. The refractive index of the filler 2 is not particularly limited as long as it is higher than that of the binder 3, but is generally 1.4 or more, preferably 1.46 or more, more preferably 1.5 or more. Is used.

When the metal oxide fine particles are used as the filler 2, the refractive index thereof is preferably in the range of 1.46 to 3.0, more preferably in the range of 1.5 to 2.5. It is preferable to select fine particles of metal oxide.

When fine particles of an organic polymer are used as the filler 2, the refractive index thereof is preferably 1.49 to 1.7.
It is preferable to select the fine particles of the organic polymer so as to fall within the above range, more preferably within the range of 1.5 to 1.67.

When hollow silica fine particles are used as the filler 2, the hollow silica particles have a refractive index of preferably 1.3 to 1.4, more preferably 1.32 to 1.37. It is preferable to select fine silica particles.

The above-mentioned filler 2 has a particle size of 5 nm to
The range of 2 μm is preferable, and 20 nm to 500 is particularly preferable.
Those of nm are more preferable. When the filler is hollow fine particles, the thickness of the outer shell is preferably 5 nm to 20 nm. The effect of lowering the average refractive index of the composite thin film 4 (that is, the refractive index as a whole of the composite thin film) is that the smaller the bulk specific gravity of the filler 2 is, the smaller the void ratio in the particles is, in the hollow particles. Is high and the particle size is small, the composite thin film 4 having excellent transparency can be obtained.
As a result, the light extraction efficiency can be increased. On the contrary, the larger the particle size, the greater the scattering effect in the composite thin film 4 and the greater the effect of suppressing the waveguiding of light, so that the light extraction efficiency can be increased. In order to have both of these effects, the particle size of the filler 2 is preferably in the above range, and the particle size of the filler 2 is the refractive index of the binder 3 constituting the composite thin film 4, the type and thickness of the light emitting element, and the like. According to the above, an appropriate one can be appropriately selected within the above range.

In the composite thin film to be formed, the abundance ratio of the binder 3 and the filler 2 may be changed according to the refractive index and density of these materials, the intended average refractive index of the composite thin film, etc. The binder 3 has a mass ratio of 40 to 95
It is preferably mass% and the mass ratio of the filler is preferably 5 to 60 mass%. The ratio of the low refractive index binder 3 is 4
If it is less than 0% by mass, the average refractive index of the composite thin film 4 will be large, and if it is more than 95% by mass, the strength of the composite thin film 4 as a film will be insufficient. There is a possibility that it cannot be done, and both may not be preferable.

When forming the composite thin film 4 on the surface of the base material 1, the liquid coating material composition prepared by mixing and dispersing the filler 2 and the binder forming material in the solvent is used as described above. After being applied to the surface of to obtain a coating film, this is dried, and if necessary, heat-treated and baked. When an airgel is used as the binder 3, it may be dried by a supercritical drying method if necessary.

In the second aspect of the present invention, the average refractive index of the composite thin film formed as described above is generally lower than the refractive index of the substrate, for example, 0.01 to 0.5, preferably It is desirable that it is smaller than 0.05 to 0.3. The average refractive index itself of the composite thin film is usually 1.1 to 1.4, preferably 1.1 to 1.35, and more preferably 1.2 to 1.3.
Is.

In FIG. 2B, the thin film light emitting element 15 is provided on the side of the composite thin film 4 opposite to the side on which the substrate 1 is located, using the composite thin film holding substrate A of FIG. 2A. The surface luminous body A is conceptually shown in a sectional view. In the illustrated form, the light emitting element 1
The light emitted at 5 passes through the composite thin film 4 and the base material 1 and is extracted from the surface of the base material 1 as indicated by the arrow. The composite thin film 4 is a composite layer of the binder 3 having a lower refractive index and the filler 2 having a higher refractive index, and the average refractive index of the composite thin film 4 is smaller than that of the substrate 1. The light passes through the interface between the light emitting element 15 and the composite thin film 4 and the inside of the composite thin film 4, and further passes through the base material 1. At this time, since the composite thin film has a smaller refractive index than the base material 1, the incident angle of light entering the base material 1 from the composite thin film 4 becomes small, and as a result, at the interface between the surface of the base material 1 and air. The amount of light reflected can be reduced to reduce the waveguiding within the substrate 1 and, if preferred, can be virtually absent.

There is also a light component that can be guided in the light emitting element 15, but the flatness is reduced at the interface between the light emitting element 15 and the composite thin film 4 due to the effect of the filler, as schematically shown. As a result, this waveguiding may be reduced by scattering at the interface. Furthermore, since the thickness of the light emitting element 15 is at most of the micron order (for example, 0.05 to 1 μm), the number of times the guided light hits the interface between the light emitting element 15 and the composite thin film 4 is extremely large, and almost the entire amount of the guided light is finally obtained. To the composite thin film 4 side. By providing the composite thin film 4 on the base material 1 in this manner, it is possible to reduce the waveguiding of light and improve the efficiency of extracting light from the surface of the base material 1.

In this composite thin film 4, the difference in refractive index between the filler 2 and the binder 3 is appropriately designed. Specifically, this difference is preferably at least 0.01, more preferably at least 0.1. . The surface of the composite thin film 4 on which the light emitting element 15 is arranged preferably has originally high flatness, but its roughness is designed by the particle size and the filling amount of the filler. On the other hand, on the other hand, when the roughness becomes large, it is expected that the waveguide component is reduced due to diffusion at the interface, and the roughness needs to be within a range in which the light emitting element 15 can be formed as a continuous film.

The filler particles 2 in the composite thin film 4 described above are used.
The space between them does not necessarily have to be completely filled with the binder 3, and a void portion (this can also be referred to as a bubble) may exist between them. The void usually contains a surrounding gas (generally air), and therefore the void has a low refractive index like the binder 3, or a refractive index lower than that. Therefore, when the voids remain between the fillers 2, the voids act in substantially the same manner as the binder 3, and as a result, the light extraction efficiency becomes higher. The refractive index of the composite thin film 4 as a whole is preferably lower than that of the substrate 1, but may be slightly higher than that of the substrate 1.

Alternatively, as in the case of the composite thin film holding substrate according to the third aspect of the present invention, the binder 3 having a refractive index higher than that of the base material 1 and the refractive index higher than that of the base material 1 are used. It is also possible to form the composite thin film 4 having an average refractive index lower than that of the base material 1 by combining the fillers. Although the substrate of the third gist is not shown, if it is shown, the drawing is similar to the substrate shown in FIG. 2 (a) cited above. Explain by quoting.

In the case of the substrate of the third aspect, the binder 3 having a refractive index higher than that of the base material 1 is not particularly limited as long as it is translucent and has a higher refractive index than the base material 1.
A binder such as the above-mentioned organic polymer or metal oxide is preferable. The refractive index of such a binder is 1.5
~ 1.8 is preferable, and the range of 1.5-1.6 is more preferable. In order to form the composite thin film 4 having a refractive index lower than that of the base material 1 by combination with a filler having a refractive index higher than that of the base material 1, the mixing ratio of the binder is small and the binder is complex. It is necessary to configure the composite thin film so as to suppress filling of voids between the fine particles of the filler in the thin film and promote bonding of the fine particles of the filler.

For example, when an organic polymer is used as the binder 3, it is preferable to select the binder forming material so that the refractive index thereof falls within the range of 1.5 to 1.7, for example. When a metal oxide is used as the binder 3, it is preferable to select the binder-forming material so that its refractive index falls within the range of 1.5 to 1.8, for example.

Despite having a combination of a binder 3 having a refractive index higher than that of the substrate 1 and a filler having a refractive index higher than that of the substrate 1, it has a lower refractive index than the substrate 1. When forming the composite thin film 4, as the filler 2 having a refractive index higher than that of the substrate 1, fine particles of the above-mentioned silica, metal oxide such as titania, fine particles of an organic polymer, or the like can be used. The refractive index of this filler 2 is
It is sufficient that the refractive index is higher than that of 1. However, it is generally 1.46 or more.

When fine particles of a metal oxide are used as the filler 2, the refractive index thereof is preferably in the range of 1.46 to 1.6, more preferably 1.46 to 1.55. It is preferable to select fine particles of metal oxide. When fine particles of an organic polymer are used as the filler 2, the refractive index of the organic polymer is preferably in the range of 1.49 to 1.65, and more preferably in the range of 1.49 to 1.6. It is preferable to select fine particles.

The above-mentioned filler 2 has a particle size of 5 nm to
The range of 2 μm is preferable, and 20 nm to 500 is particularly preferable.
Those of nm are more preferable. When the filler is hollow fine particles, the thickness of the outer shell is preferably 5 nm to 20 nm. The smaller the binder / filler ratio in the solid content in the coating material of the filler 2, that is, the smaller the occupation ratio of the binder to fill the voids between the fillers, the smaller the average refractive index of the composite thin film 4 ( That is, the refractive index of the composite thin film as a whole can be lowered.
Further, the smaller the particle size, the more transparent the composite thin film 4 is obtained, and as a result, the light extraction efficiency can be increased. On the contrary, the larger the particle size, the greater the scattering effect in the composite thin film 4 and the greater the effect of suppressing the waveguiding of light, so that the light extraction efficiency can be increased. In order to have both of these effects, the particle size of the filler 2 is preferably in the above range, and the particle size of the filler 2 is the composite thin film 4.
Depending on the refractive index of the binder 3 constituting the above, the type and thickness of the light emitting element, etc., an appropriate one can be appropriately selected within the above range.

A composite thin film 4 composed of a binder and a filler, each of which has a refractive index higher than that of the substrate.
In the above, the composition ratio of the binder 3 and the filler 2 may be changed according to the refractive index, the density of these materials, the average refractive index of the intended composite thin film, etc.
Is preferably 5 to 20% by mass, and the mass ratio of the filler is preferably 80 to 95% by mass.

When forming a composite thin film with a binder and a filler, each of which has a refractive index higher than that of the substrate, the binder is present only for binding the filler, as described above. However, it is necessary that most of the spaces between the fillers are not occupied by the binder and remain as spaces. In the composite thin film having such a structure, the volume filling rate of the filler in the composite thin film is 5
It should occupy 0% to 75%, and the void ratio in the composite thin film should be 25% or more.

The mass ratio of the binder 3 having a high refractive index is 20.
When it is higher than mass%, the binder easily fills the voids between the fine particles of the filler, and as a result, the average refractive index of the composite thin film 4 becomes large, and when it is higher than 95 mass%, the composite thin film is increased. In some cases, the strength of the film of No. 4 becomes insufficient, and the purpose may not be achieved in some cases.

Similar to the embodiment shown in FIG. 2B, the thin-film light emitting element 15 is used on the side of the composite thin film 4 opposite to the side on which the base material 1 is located, using the composite thin film holding substrate of the third aspect. It is natural that a surface light emitting device can be obtained by providing

In the composite thin film holding substrate A of FIGS. 1 (a) and 2 (a), the surface of the composite thin film 4 provided on the base material 1 (that is, the surface opposite to the base material 1 side). If the roughness is too high, it is preferable to provide a smoothing underlayer on the surface of the composite thin film 4 opposite to the base material 1 to fill the irregularities on the surface of the composite thin film 4 for smoothing. Such a smoothing base layer 6 is
In addition to the composite thin film holding substrate A of FIG.
The composite thin film holding substrate A of FIG.
FIG. 3A and FIG. 3B are schematic sectional views. By providing the smoothing base layer 6 in this manner, it is possible to form, on the composite thin film 4, a thin film such as an organic electroluminescence device that requires smoothness between thin films and high uniformity of thickness. Will be easier.

The material forming the smoothing underlayer 6 is not particularly limited, but a material having a refractive index close to that of a layer such as a thin film formed on the smoothing underlayer 6 is preferable. . Specifically, silica, silicon nitride, alumina,
Aluminum nitride, metal oxides and metal nitrides such as titania, magnesium fluoride, fluorinated compounds such as fluoropolymers, acrylic polymers, epoxy polymers,
Parylene or the like can be used. As a method for forming the smoothing base layer 6, vacuum deposition, sputtering, CV
Examples thereof include a vapor deposition method such as D, a coating method of forming a coating film on the composite thin film 4 and then removing volatile components by drying.

Composite thin film holding substrate A formed as described above
A transparent conductive film may be formed on the surface of the substrate and on the side opposite to the side where the substrate is located. At this time, when the exposed surface of the composite thin film is not flat, the smoothing base layer 6 may be formed on the composite thin film, and the transparent conductive film may be formed thereon, as described above.

A form in which the transparent conductive film is formed in this way is schematically shown in a sectional view in FIG. The form shown in FIG. 4 shows a transparent conductive film holding substrate B formed by providing a transparent conductive film 5 on the composite thin film 4 of the composite thin film holding substrate A formed as described above. . In the embodiment shown in FIG. 4, the smoothing base layer 6 is provided on the surface of the composite thin film 4 opposite to the base material 1, and the transparent conductive film 5 is formed on the smoothing base layer 6. FIG. 4A shows the composite thin film holding substrate A of FIG. 3A provided with the transparent conductive film 5, and FIG.
3A and 3B respectively show the composite thin film holding substrate A of FIG. 3B provided with the transparent conductive film 5. In this way, the smoothing base layer 6
By forming the transparent conductive film 5 on the transparent conductive film 5, it becomes easy to form the transparent conductive film 5 on a thin film having a smooth surface and high thickness uniformity.

The transparent conductive film 5 may be one that can be used as an anode when forming an electroluminescence element as described later. In that case, examples of the material of the transparent conductive film 5 include indium tin oxide (ITO), zinc oxide, tin oxide, indium zinc oxide (IZO), and conductive polymers, but are not particularly limited. As the method of forming the transparent conductive film 5, as in the case of the smoothing base layer 6, a vapor phase growth method, a coating method, or the like can be appropriately selected.

Depending on the type of the transparent conductive film 5 and the method of forming the transparent conductive film 5, it is possible to form the transparent conductive film 5 having a smooth surface even if the underlying smoothness is low. In that case, the transparent conductive film 5 can be directly formed on the composite thin film 4 without providing the smoothing base layer 6. For example, in the case of forming a transparent conductive film 5 by forming an amorphous metal oxide represented by IZO by a vapor phase growth method,
This corresponds to the case where the transparent conductive film 5 is formed by forming a film of a conductive polymer and ITO fine particles by a coating method.

The embodiment shown in FIG. 5 is a schematic cross-sectional view of a surface light emitter C in which a thin film 7 of a phosphor is provided on a composite thin film 4 in a composite thin film holding substrate A manufactured as described above. Indicate. In the embodiment shown in FIG. 5, the thin film 7 of the phosphor is provided directly on the surface of the composite thin film 4 opposite to the substrate 1. The thin film 7 contains an organic or inorganic phosphor that emits light when excited by irradiation with ultraviolet rays or electron beams, and forms a surface light-emitting body C as a photoluminescent element. This surface light emitter C is particularly useful in self-luminous displays such as CRTs, FEDs and PDPs. FIG. 5A shows FIG.
FIG. 5B shows the composite thin film holding substrate A of FIG. 2A provided with the phosphor thin film 7, and FIG.
In each of the figures, a thin film 7 of phosphor is provided. Since the phosphor thin film 7 is in contact with the surface of the composite thin film 4 in this way, the light extraction efficiency is improved due to the unevenness of the surface of the composite thin film 4 due to the presence of the filler 2.

The material of the phosphor is not particularly limited, and any organic or inorganic material conventionally used in photoluminescence devices can be used. As a method for forming the phosphor thin film 7, a vapor phase growth method such as a sputtering method or a MOCVD method (organic metal vapor phase growth method) is used for an inorganic phosphor, and a vacuum deposition is used for a low molecular weight organic phosphor. Examples of the method include coating methods such as spin coating and inkjet coating in the case of polymer organic fluorescent substance.

In the embodiment shown in FIG. 6, in the above-mentioned transparent conductive film holding substrate B, the light emitting layer 8 and the metal electrode 9 are laminated on the transparent conductive film 5 to form the electroluminescent element 10. The surface luminous body D is schematically shown in a sectional view. That is, the element 10 is formed on the composite thin film holding substrate A. Electroluminescence element 10
Has a transparent conductive film 5 as an anode and a metal electrode 9 of a metal thin film as a cathode, and a light emitting layer 8 is laminated between the anode and the cathode. The form of FIG.
The organic electroluminescent element 10 is shown, and the hole transport layer 19 is provided between the transparent conductive film 5 serving as an anode and the light emitting layer 8.
However, an electron transport layer 20 is laminated between the light emitting layer 8 and the metal electrode 9 serving as a cathode, if necessary. In the case of the inorganic electroluminescence 10, a dielectric layer is laminated on one side or both sides of the light emitting layer 8. As the materials for the light emitting layer 8, the metal electrode 9, the hole transport layer 19, and the electron transport layer 20, those conventionally used in the manufacture of electroluminescence can be used as they are.

Incidentally, FIG. 6A shows that the organic electroluminescent element 10 is formed on the transparent conductive film holding substrate B of FIG. 4A.
6B, the organic electroluminescence element 10 is provided on the transparent conductive film holding substrate B of FIG. 4B.
Are provided respectively. In the organic electroluminescence element 10, when a positive voltage is applied to the transparent conductive film 5 serving as an anode and a negative voltage is applied to the metal electrode 9 serving as a cathode, electrons injected into the light emitting layer 8 through the electron transport layer 20, The holes injected into the light emitting layer 8 through the hole transport layer 19 are recombined in the light emitting layer 8 to emit light.

[0135]

EXAMPLES Next, the present invention will be described more specifically by way of examples. The weight average molecular weight was measured by GPC (gel permeation chromatography) using HLC8020 manufactured by Tosoh Corporation as a measuring instrument to prepare a calibration curve using standard polystyrene, and measuring it as the converted value.

Example 1 Tetraethoxysilane 208
356 parts by weight of methanol was added to the parts by weight, and water 18
A solution was obtained by adding 18 parts by mass of 0.01 N hydrochloric acid and thoroughly mixing them with a disper. The resulting solution was stirred for 2 hours in a constant temperature bath at 25 ° C. to obtain Silicone Resin-M (a product obtained by condensation polymerization of tetraethoxysilane by hydrolysis) as a binder-forming material having a weight average molecular weight of 850. Next, this silicone resin
M is a hollow silica IPA dispersion sol (solid content: 20 mass%, dispersion medium: isopropyl alcohol, average primary particle diameter: about 35 nm, outer shell thickness: about 8).
nm, manufactured by Catalysts & Chemicals Industry Co., Ltd.) is added so that the total solid content is 1 in the hollow silica fine particles / silicone resin-M (condensation compound conversion) solid content mass basis of 80/20.
The mixture was diluted with methanol to 0% by mass to obtain a coating material composition containing hollow silica fine particles. still,
The term "condensed compound conversion" means, for example, the weight assuming that the existing Si is SiO ₂ in the case of tetraalkoxysilane (tetraethoxysilane in this case), and the weight assuming that it is SiO _1.5 in the case of trialkoxysilane. Is.

Next, using a glass plate as a substrate, the obtained coating material composition was applied to the surface of the glass plate by a spin coater at 1000 rpm and dried to obtain a film. The composite thin film holding substrate having a structure as shown in FIG. 1A was manufactured by performing heat treatment by baking for minutes. The refractive index of the glass plate is 1.
52, the refractive index of the hollow silica fine particles was 1.25, and the refractive index of the silicone resin-M coated, dried and heat treated, that is, the binder was 1.45.

Example 2 Tetramethoxysilane 152
64 parts by mass of methanol was added to parts by mass and well mixed using a disper to obtain a solution of a binder-forming material that forms a silica airgel binder. To 216 parts by mass of this solution, 64 parts by mass of methanol and 3 parts of water
6 parts by weight, 0.6 parts by weight of 28% by weight aqueous ammonia, and polystyrene fine particle dispersed sol (solid content: 1% by weight, average primary particle size: about 100 nm, Duke Sci)
(manufactured by Entific) was added and mixed in a concentration of 50 times to obtain a coating material composition containing polystyrene fine particles in which the proportion of polystyrene fine particles in the mixture was adjusted to 10% by mass.

Next, using a glass plate as a substrate, the coating material composition was applied to the surface of the glass plate by a spin coater under the conditions of 1000 rpm to form a coating film. By performing supercritical drying under the condition of 160 kg / cm ² , a composite thin film holding substrate having a structure as shown in FIG. 2A was produced. Here, the refractive index of the glass plate is 1.52, and the refractive index of the polystyrene fine particles is 1.5.
9. The refractive index of the binder after supercritical drying is 1.18.

(Comparative Example 1) The glass plates used in Examples 1 and 2 were used as they were without treatment, and were used as Comparative Example 1.

(Comparative Example 2) The glass plates used in Examples 1 and 2 were coated with only the silicone resin-M obtained in Example 1 (thus, containing no hollow silica fine particles) in the same manner as in Example 1. This was designated as Comparative Example 2.

With respect to the substrates obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the total light transmittance and the average refractive index of the composite thin film were measured. Here, the total light transmittance was measured by measuring the total light transmittance at a wavelength of 550 nm using a spectrophotometer (“U-3400” manufactured by Hitachi, Ltd.). Further, the average refractive index of the composite thin film is measured by observing the fracture surface of the substrate with a scanning electron microscope to measure the film thickness of the composite thin film, and then measuring the thickness of the composite thin film by using an ellipsometer (“EMS-made by ULVAC”).
1 ”) was used to measure the refractive index. The results are shown in Table 1.

When the pencil hardness of the composite thin films of the substrates obtained in Examples 1 and 2 was measured, the pencil hardness was 2H in the case of Example 1 and 5H in the case of Example 2. As shown, these were practically sufficiently strong. The refractive index of 1.
In the case of the low refractive index thin film of No. 2, the pencil hardness was softer than that of B, and it was very likely to be scratched and difficult to handle.

[0144]

[Table 1]

Example 3 Using the composite thin film holding substrate obtained in Example 1, plasma CVD using tetraethoxysilane as a source was performed on the composite thin film at 300 ° C.
A smoothing underlayer made of a SiO ₂ film having a film thickness of 100 nm was formed on the surface of the composite thin film. Next, RF sputtering is performed on the smoothing underlayer at 200 ° C. to form a transparent conductive film made of an ITO thin film having a film thickness of 100 nm, and the transparent conductive film as shown in FIG. A film holding substrate was produced.

Example 4 Holding of the composite thin film obtained in Example 2
SiH on the composite thin film using the substrate_FourGas and N _Twogas
Plasma CVD with a source of
A smoothing underlayer made of a SiN film having a thickness of 100 nm
Was formed on the surface of the composite thin film. Next, of this smoothing underlayer
By RF sputtering under the condition of 200 ℃
Transparent conductivity consisting of 100 nm thick IZO thin film
A transparent conductive film holding substrate having a film formed thereon as shown in FIG.
Was produced.

(Comparative Example 3) A transparent conductive film made of an ITO thin film was formed directly on the surface of the glass plate used in Examples 1 and 2 in the same manner as in Example 3, and this was designated as Comparative Example 3.

(Comparative Example 4) A transparent conductive film made of an IZO thin film was formed directly on the surface of the glass plate used in Examples 1 and 2 in the same manner as in Example 4, and this was designated as Comparative Example 4.

With respect to the transparent conductive film holding substrates obtained in Examples 3 and 4 and Comparative Examples 3 and 4, the total light transmittance and the sheet resistance value of the transparent conductive film were measured. here,
The sheet resistance value was measured using a Hall effect measuring device (“HL5500” manufactured by Accent Optical Technology Co., Ltd.). The results are shown in Table 2.

[0150]

[Table 2]

Example 5 Using the composite thin film holding substrate obtained in Example 1, tris (8-hydroquinoline) aluminum (“Alq3” manufactured by Dojindo Laboratories) was used as a phosphor thin film on the composite thin film. Was formed into a film having a thickness of 100 nm, and a surface light emitting body as shown in FIG. 5A was produced as a photoluminescence element.

(Example 6) Using the composite thin film holding substrate obtained in Example 2, a phosphor thin film was formed on the composite thin film in the same manner as in Example 5 to obtain a photoluminescence element as shown in FIG. ) Was produced.

(Comparative Example 5) A thin film of a phosphor was formed directly on the surface of the glass plate used in Examples 1 and 2 in the same manner as in Example 5 to prepare a surface-emitting body as a photoluminescence element.

With respect to the surface luminous bodies obtained in Examples 5 and 6 and Comparative Example 5, the phosphor thin film was irradiated with a 20 W ultraviolet fluorescent lamp, and the surface luminance of the glass substrate was measured with a luminance meter (“LS-110 manufactured by Minolta Co., Ltd.”). ]) Was used for the measurement. The results are shown in Table 3.
Shown in.

[0155]

[Table 3]

Example 7 Using the transparent conductive film-holding substrate obtained in Example 3, N, N-diphenyl-N, N-bis-3- was formed on the transparent conductive film by vacuum deposition. Methylphenyl-1,1-diphenyl-4,4-diamine (α
-NPD) with a thickness of 50 nm, tris (8-hydroquinoline) aluminum (Alq3) with a thickness of 50 nm,
A film of Al having a thickness of 100 nm was formed, a hole transport layer, a light emitting layer, and a metal electrode were laminated to form an organic electroluminescence element, and a surface light emitter as shown in FIG. 6A was produced.

Example 8 An organic electroluminescence device was formed in the same manner as in Example 7 by using the transparent conductive film holding substrate obtained in Example 4 to produce a surface light emitting device as shown in FIG. 6B. Was produced.

Comparative Example 6 Using the transparent conductive film holding substrate obtained in Comparative Example 3, an organic electroluminescence device was formed in the same manner as in Example 7 to prepare a surface light emitting device.

(Comparative Example 7) Using the transparent conductive film holding substrate obtained in Comparative Example 4, an organic electroluminescence device was formed in the same manner as in Example 7 to prepare a surface light emitting body.

With respect to the surface luminous bodies obtained in Examples 7 and 8 and Comparative Examples 6 and 7, a direct current power supply of 10 V was connected between the transparent conductive film and the metal electrode of the Al film to emit light, and the surface of the glass substrate The brightness of the brightness of the
110 "). The results are shown in Table 4.

[0161]

[Table 4]

[0162]

In the composite thin film holding substrate according to the first aspect of the present invention, by providing a filler having a refractive index smaller than that of the base material on the surface of the base material, it is possible to guide light inside the substrate. The wave component can be reduced, and the light extraction efficiency can be increased. Further, when a composite thin film composed of a filler having a refractive index lower than that of the base material and a binder having a refractive index higher than that of the filler is formed, a composite composed of the filler and the binder having different refractive indexes is formed. Some light is scattered as it passes through the membrane. Due to the synergistic effect, when the light emitting element is provided on the composite thin film of this substrate, the light guided in the light emitting element is reduced, and the light passing through the composite thin film has high extraction efficiency from the base material to the outside (atmosphere). Become.

In the composite thin film holding substrate according to the second aspect of the present invention, the surface of the base material comprises a binder having a refractive index lower than that of the base material and a filler having a refractive index higher than that of the binder. The same applies when the composite thin film is formed.

In the composite thin film holding substrate of the third aspect of the present invention, the surface of the base material comprises a binder having a higher refractive index than the base material and a filler having a higher refractive index than the base material. The same applies to the case where the following composite thin film is formed.

In the composite thin film holding substrate according to the first aspect,
The filler having a lower refractive index than the base material is selected from airgel fine particles, hollow silica fine particles and polymer hollow fine particles, and the binder having a higher refractive index than the filler is selected from organic polymers and metal oxides. In this case, the effect of increasing the efficiency of extracting light to the outside by the composite thin film including the filler and the binder can be improved.

In the composite thin film holding substrate according to the second aspect,
The binder whose refractive index is lower than the base material is airgel,
When the filler having a refractive index higher than that of the binder is fine particles selected from an organic polymer and a metal compound, it is possible to improve the effect of enhancing the light extraction efficiency to the outside by the composite thin film including the binder and the filler.

In any of the composite thin film holding substrates described above, when the refractive index is lower than that of the base material but is 1.35 or less, the average refractive index of the composite thin film can be made low, and The light extraction efficiency can be further enhanced.

The transparent conductive film holding substrate of the present invention in which a transparent conductive film is formed on the composite thin film of the composite thin film holding substrate according to any one of the above, is a transparent conductive film having a high light extraction efficiency to the outside. A film holding substrate can be obtained.

In the transparent conductive film holding substrate of the present invention,
When the smoothing underlayer is formed on the composite thin film, and the transparent conductive film is formed thereon, the transparent conductive film can be formed as a thin film having a smooth surface and high uniformity of thickness, and It is possible to obtain a transparent conductive film holding substrate having a high efficiency of extracting light to the outside.

The surface-emitting body of the present invention has a thin film of an organic or inorganic phosphor that emits light when excited by ultraviolet rays or an electron beam, and is formed on the composite thin film of the composite thin film holding substrate. It is possible to obtain a surface-emitting body having a high extraction efficiency of.

Another surface light-emitting device of the present invention has an electroluminescent element formed by laminating a light-emitting layer and a metal electrode in this order on a transparent conductive film of a transparent conductive film holding substrate, which is exposed to the outside. It is possible to obtain a surface light emitter having a high light extraction efficiency.

[Brief description of drawings]

1A and 1B are cross-sectional views schematically showing an example of the form of a composite thin film holding substrate of the present invention, FIG.
In, a light emitting element is provided.

2A and 2B are cross-sectional views schematically showing another example of the form of the composite thin film holding substrate of the present invention, in which the light emitting element is provided in FIG. 2B.

3 (a) and (b) are shown in FIG. 1 (a) and FIG.
It is sectional drawing which shows typically the form which provided the smoothing base layer on the composite thin film holding substrate of (a).

4 (a) and (b) are the same as FIG. 3 (a) and FIG.
It is sectional drawing which shows typically the form which provided the transparent conductive film on the composite thin film holding substrate of (b).

5 (a) and (b) are shown in FIG. 1 (a) and FIG.
It is sectional drawing which shows typically the form which provided the fluorescent substance thin film on the composite thin film holding substrate of (a).

6 (a) and (b) are the same as FIG. 3 (a) and FIG.
It is sectional drawing which shows typically the form which provided the electroluminescent element on the composite thin film holding substrate of (b).

FIG. 7 is a cross-sectional view showing an example of a conventional light emitting body.

FIG. 8 is a cross-sectional view showing another example of a conventional light emitting body.

FIG. 9 is a sectional view showing still another example of a conventional light emitting body.

[Explanation of symbols] 1 base material 2 Filler 3 binders 4 Composite thin film 5 Transparent conductive film 6 Smoothing base layer 7 Phosphor thin film 8 light emitting layer, 9 metal electrodes 10 Electroluminescence element

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) C09D 183/04 C09D 183/04 201/00 201/00 H05B 33/02 H05B 33/02 33/14 33 / 14 A (72) Inventor Hikaru Tsujimoto 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Inventor ▲ Taka ▼ Koichi Hama 1048 Kadoma, Kadoma City, Osaka Matsushita Electric Works Co., Ltd. (72) Inventor Masaru Yokoyama 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works Co., Ltd. (72) Inventor, Yasuhisa Kishigami, Kadoma, Osaka Prefecture, 1048, Matsushita Electric Works Co., Ltd. (72), Nobuhiro Ide, Kadoma City, Osaka Daiji Kadoma 1048 Matsushita Electric Works Co., Ltd. (72) Inventor Kenji Kono Kadoma City, Osaka Prefecture 1048 Kadoma Matsushita Electric Co., Ltd. (72) Inventor Yoshihiro Ito Kadoma City, Osaka 10 Kadoma Shin 48 address Matsushita Electric Works Co., Ltd. in the F-term (reference) 3K007 AB03 BB06 CA00 DB03 4F100 AA01C AA17B AA20B AG00A AK01B AK52B AS00B AT00A BA02 BA03 BA07 BA10A BA10C CA23B DE04B DJ00B EH46B GB41 JA20B JG01C JK15B JM02B JN01C JN13C JN18B YY00B 4J038 AA011 CC031 CC032 CD091 CD092 CG141 CG142 DB001 DL031 DL032 HA211 HA216 HA441 HA446 KA08 KA12 KA18 KA20 KA21 MA04 NA01 NA19 NA20 PA07 PA18 PB09 5C094 AA10 BA27 EB02 ED12

Claims (24)

[Claims] 1. A composite thin film holding substrate comprising a base material and a composite thin film disposed on the surface thereof, the composite thin film comprising a filler and a binder, wherein the filler has a refractive index (Nf). , Smaller than the refractive index (Nb) of the binder,
A composite thin film holding substrate having a refractive index (Ns) smaller than that of the base material. 2. A composite thin film holding substrate comprising a base material and a composite thin film disposed on the surface thereof, wherein the composite thin film comprises a filler and a binder, and the refractive index (Nb) of the binder is Smaller than the refractive index (Nf) of the filler,
A composite thin film holding substrate having a refractive index (Ns) smaller than that of the base material. 3. A composite thin film holding substrate comprising a base material and a composite thin film disposed on the surface of the composite thin film, the composite thin film comprising a filler and a binder, the refractive index (Nf) of the filler and A composite thin film holding substrate in which both the refractive index (Nb) of the binder is higher than the refractive index (Ns) of the base material. 4. The composite thin film holding substrate according to claim 1, wherein the filler is selected from airgel fine particles, hollow silica fine particles and polymer hollow fine particles, and the binder is selected from organic polymers and metal oxides. 5. The composite thin film holding substrate according to claim 2, wherein the binder is a porous silica material and the filler is selected from organic polymer fine particles, metal compound fine particles and hollow silica fine particles. 6. The composite thin film holding substrate according to claim 3, wherein the filler is selected from organic polymer particles and metal oxide particles, and the binder is selected from organic polymers and metal oxides. 7. The composite thin film holding substrate according to claim 4, wherein the composite thin film has a refractive index of 1.4 or less. 8. The composite thin film holding substrate according to claim 5, wherein the composite thin film has a refractive index of 1.4 or less. 9. The composite thin film holding substrate according to claim 6, wherein the composite thin film has a refractive index of 1.4 or less. 10. The refractive index of the filler is 1.3 or less,
The composite thin film holding substrate according to claim 7. 11. The composite thin film holding substrate according to claim 8, wherein the binder has a refractive index of 1.5 or less. 12. The composite thin film holding substrate according to claim 9, wherein the binder has a refractive index of 1.8 or less. 13. A transparent conductive film holding substrate having a transparent conductive film, which is transparent on the composite thin film of the composite thin film holding substrate according to any one of claims 1, 4, 7, and 10. A transparent conductive film holding substrate on which a conductive film is formed. 14. A transparent conductive film holding substrate having a transparent conductive film, which is transparent on the composite thin film of the composite thin film holding substrate according to any one of claims 2, 5, 8, and 11. A transparent conductive film holding substrate on which a conductive film is formed. 15. A transparent conductive film holding substrate having a transparent conductive film, which is transparent on the composite thin film of the composite thin film holding substrate according to any one of claims 3, 6, 9, and 12. A transparent conductive film holding substrate on which a conductive film is formed. 16. The transparent conductive film holding substrate according to claim 13, wherein the transparent conductive film is formed on a smoothing base layer formed on the composite thin film. 17. The transparent conductive film holding substrate according to claim 14, wherein the transparent conductive film is formed on a smoothing base layer formed on the composite thin film. 18. The transparent conductive film holding substrate according to claim 15, wherein the transparent conductive film is formed on a smoothing base layer formed on the composite thin film. 19. A surface light emitter comprising a thin film of a fluorescent substance, which is formed on the composite thin film of the composite thin film holding substrate according to claim 4 and emits light when excited by ultraviolet rays or electron beams. A surface light emitter on which a thin film of an inorganic phosphor is formed. 20. The light emitting layer and the metal electrode are laminated in this order on the transparent conductive film of the transparent conductive film holding substrate according to claim 13, and the transparent conductive film, the light emitting layer and the metal electrode are electroluminescent. A surface light emitter that constitutes an element. 21. A light emitting layer and a metal electrode are laminated in this order on the transparent conductive film of the transparent conductive film holding substrate according to claim 14, and the transparent conductive film, the light emitting layer and the metal electrode are electroluminescent. A surface light emitter that constitutes an element. 22. A light emitting layer and a metal electrode are laminated in this order on the transparent conductive film of the transparent conductive film holding substrate according to claim 15, and the transparent conductive film, the light emitting layer and the metal electrode are electroluminescent. A surface light emitter that constitutes an element. 23. The composite thin film is formed by drying a coating film formed by applying a coating material composition comprising hollow silica fine particles and a silicone resin to a substrate. Composite thin film holding substrate. 24. The average particle diameter of the hollow silica fine particles is 5 n.
The composite thin film holding substrate according to claim 23, which has a thickness of m to 2 μm.