JP2016048596A - Manufacturing method for translucent substrate, the translucent substrate, and organic led element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a translucent substrate in which coloring is significantly restrained and a manufacturing method.SOLUTION: A translucent substrate 100 has a glass substrate 110 and an ITO film 140 formed on the glass substrate 110. The glass substrate 110 includes at least one of a chemical element selected from a group of Bi (bismuth), Ti (titanium), and Sn (stannum), and an oxidation level of the ITO film 140 at a side near by the glass substrate 110 is higher than the ITO film at a side far from the glass substrate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a translucent substrate and an organic LED element including such a translucent substrate.

  Organic LED (Light Emitting Diode) elements are widely used in displays, backlights, lighting applications, and the like.

  A general organic LED element has a first electrode (anode) placed on a glass substrate, a second electrode (cathode), and an organic light emitting layer placed between these electrodes. When a voltage is applied between the electrodes, holes and electrons are injected from each electrode into the organic light emitting layer. When the holes and electrons are recombined in the organic light emitting layer, binding energy is generated, and the organic light emitting material in the organic light emitting layer is excited by this binding energy. Since light is emitted when the excited light emitting material returns to the ground state, a light emitting (LED) element can be obtained by utilizing this.

  Usually, a transparent electrode layer such as ITO (Indium Tin Oxide) is used for the first electrode, that is, the anode, and a metallic light such as aluminum and silver is used for the second electrode, that is, the cathode. An electrode layer is used.

  Patent Document 1 discloses that an ITO film having two layers is formed on a glass substrate.

JP 2005-268616 A

Usually, when manufacturing an organic LED element, a transparent electrode layer is formed as a 1st electrode on a glass substrate. (A member formed by forming a transparent electrode layer on a glass substrate is often referred to as a “translucent substrate.” The “translucent substrate” reaches, for example, a product such as an organic LED element. (Used as the previous semi-finished product.)
However, in the research by the inventors of the present application, a phenomenon in which coloring occurs in the glass substrate is often recognized when an ITO film is formed on the glass substrate.

  Such coloring of the glass substrate greatly affects the characteristics of the translucent substrate and further the organic LED element. For example, in an organic LED element provided with a colored glass substrate, light generated in the organic light emitting layer is absorbed inside the element during use, which may cause a problem that the light extraction efficiency is greatly reduced.

  In addition, the glass substrate of patent document 1 is non-alkali glass, and does not contain bismuth oxide or titanium oxide as a glass composition. Therefore, Patent Document 1 does not recognize any of the above-described problems.

  The present invention has been made in view of such problems, and in the present invention, a translucent substrate in which the occurrence of coloring, which is not recognized in the prior art documents, is significantly suppressed, and such a translucent substrate. It aims at providing the organic LED element which has this. Another object of the present invention is to provide a method for producing a translucent substrate in which the occurrence of coloring is significantly suppressed.

In the present invention, there is provided a method for producing a translucent substrate having a glass substrate, a scattering layer formed on the glass substrate, and an ITO film formed on the scattering layer,
A step of disposing a scattering layer having a base material made of glass and a plurality of scattering materials dispersed in the base material on a glass substrate, wherein the scattering layer includes Bi (bismuth), Ti (titanium) And at least one element selected from the group consisting of Sn (tin);
Forming an ITO film on the scattering layer;
Have
The manufacturing method is characterized in that the ITO film is formed so that the side closer to the glass substrate has a higher degree of oxidation than the side far from the glass substrate.

Further, in the present invention, a method for producing a translucent substrate having a glass substrate and an ITO film on the glass substrate,
Providing a glass substrate containing at least one element selected from the group consisting of Bi (bismuth), Ti (titanium), and Sn (tin);
Forming an ITO film on the glass substrate;
Have
The manufacturing method is characterized in that the ITO film is formed so that the side closer to the glass substrate has a higher degree of oxidation than the side far from the glass substrate.

  Here, in the manufacturing method according to the present invention, the step of forming the ITO film reduces the degree of oxidation continuously or discontinuously from the side closer to the glass substrate toward the side farther from the glass substrate. The ITO film may be formed.

In the manufacturing method according to the present invention, the step of forming the ITO film includes the step of forming the ITO film by a sputtering method,
In the first stage of film formation, the ratio R (vol% · cm ² / W) of the oxygen partial pressure P _O2 (vol%) to the plasma power density P _d (W / cm ² ) compared to the stage at the end of film formation. ) (R = P _O2 / P _d ) may be large.

In particular, in the manufacturing method according to the present invention, the ratio R (vol% · cm ² / W) in the initial stage of the film formation may be 1.5 (vol% · cm ² / W) or more.

In the manufacturing method according to the present invention, the step of forming the ITO film includes:
(I) depositing a first ITO layer; and thereafter
(Ii) depositing a second ITO layer on top of the first ITO layer;
You may have.

In this case, the first and second ITO layers are formed by sputtering,
In the step (i), as compared with the step (ii), the ratio R (vol% · cm ² / W) of the oxygen partial pressure P _O2 (vol%) to the plasma power density P _d (W / cm ² ). ) (R = P _O2 / P _d ) may be large.

In particular, in the step (i), the ratio R (vol% · cm ² / W) may be 1.5 (vol% · cm ² / W) or more.

In the manufacturing method according to the present invention, the ITO film may have a resistivity of less than 2.38 × 10 ⁻⁴ Ωcm.

In addition, the manufacturing method according to the present invention, before the step of forming the ITO film,
A step of forming a coating layer containing a metal oxide and / or a metal oxynitride on the glass substrate or the scattering layer may be included.

Furthermore, in the present invention, a translucent substrate having a glass substrate and an ITO film formed on the glass substrate,
The glass substrate includes at least one element selected from the group consisting of Bi (bismuth), Ti (titanium), and Sn (tin),
The ITO film is provided with a translucent substrate characterized in that the side closer to the glass substrate has a higher degree of oxidation than the side farther from the glass substrate.

Further, in the present invention, a translucent substrate having a glass substrate, a scattering layer formed on the glass substrate, and an ITO film formed on the scattering layer,
The scattering layer includes at least one element selected from the group consisting of Bi (bismuth), Ti (titanium), and Sn (tin),
The ITO film is provided with a translucent substrate characterized in that the side closer to the scattering layer has a higher degree of oxidation than the side far from the scattering layer.

  Here, in the translucent substrate according to the present invention, the ITO film may be continuously or discontinuously reduced in the degree of oxidation from the side closer to the glass substrate toward the side farther from the glass substrate. .

  In the translucent substrate according to the present invention, the ITO film may have a thickness of 2 nm to 500 nm.

In the translucent substrate according to the present invention, the ITO film is composed of at least two layers, a first ITO layer closer to the glass substrate, and a second ITO farther from the glass substrate. Has a layer,
The first ITO layer may be in a state of higher oxidation than the second ITO layer.

In the translucent substrate according to the present invention, the ITO film may have a resistivity of less than 2.38 × 10 ⁻⁴ Ωcm.

  In the translucent substrate according to the present invention, the ITO film may have an extinction coefficient of 0.0086 or less.

  The translucent substrate according to the present invention may have an absorption coefficient of 6% or less with respect to light having a wavelength of 500 nm.

  The translucent substrate according to the present invention further includes a coating layer containing a metal oxide and / or a metal oxynitride between the glass substrate and the ITO film or between the scattering and the ITO film. You may do it.

Furthermore, in this invention, it is an organic LED element which has a glass substrate, a 1st electrode layer, an organic light emitting layer, and a 2nd electrode layer in this order,
There is provided an organic LED element including a translucent substrate having the above-described characteristics.

  In the present invention, it is possible to provide a translucent substrate in which the occurrence of coloring is significantly suppressed, and an organic LED element having such a translucent substrate. Moreover, in this invention, the manufacturing method of the translucent board | substrate with which generation | occurrence | production of coloring was suppressed significantly can be provided.

It is a schematic sectional drawing of the 1st translucent board | substrate by one form of this invention. It is a schematic sectional drawing of the 2nd translucent board | substrate by one form of this invention. It is a schematic sectional drawing of the 3rd translucent board | substrate by one form of this invention. It is a schematic sectional drawing of the organic LED element by one form of this invention. It is the flowchart which showed roughly an example of the manufacturing method of the organic LED element by this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

(First translucent substrate)
FIG. 1 is a schematic cross-sectional view of a first light-transmitting substrate according to an embodiment of the present invention.

  As shown in FIG. 1, the first translucent substrate 100 according to an embodiment of the present invention includes a glass substrate 110 and an ITO film 140 formed on the glass substrate 110.

  The glass substrate 110 contains at least one element of bismuth (Bi), titanium (Ti), and tin (Sn).

  Although not shown in FIG. 1, a coating layer may be provided between the glass substrate 110 and the ITO film 140. Such a coating layer functions as an anti-etching barrier that prevents elution and deterioration of the glass substrate 110 when the ITO film 140 is patterned, for example. The coating layer is made of, for example, a metal oxide or a metal oxynitride. However, the coating layer is not an essential component and may be omitted as shown in FIG.

  The ITO film 140 functions as one electrode (anode) when a finished product, for example, an organic LED element is formed from the first light-transmissive substrate 100.

  The ITO film 140 has a first surface 142 on the side close to the glass substrate 110 and a second surface 144 on the side far from the glass substrate 110.

  Here, the ITO film 140 is characterized in that the first surface 142 side has a higher degree of oxidation (degree of oxidation) than the second surface 144 side. Further, the conductivity on the second surface 144 side is higher than that on the first surface 142 side.

  Here, the effect of the ITO film 140 configured as described above will be described.

  According to the inventors of the present application, when an ITO film is formed on a glass substrate, it is often recognized that the glass substrate is colored. Such coloring of the glass substrate greatly affects the characteristics of the translucent substrate and further the organic LED element. For example, in an organic LED element provided with a colored glass substrate, light generated in the organic light emitting layer is absorbed inside the element during use, which may cause a problem that the light extraction efficiency is greatly reduced.

  When the glass substrate contains a specific component, more specifically, the glass substrate is more specifically selected from bismuth (Bi), titanium (Ti), and tin (Sn). In the presence of at least one element (hereinafter these elements are collectively referred to as “reducible elements”).

  On the other hand, the atmosphere for forming the ITO film is usually an atmosphere with relatively little oxygen. This is because if the ITO film is formed in an “oxygen-excess” atmosphere, the conductivity of the obtained ITO film is lowered and it becomes difficult to use it as an electrode of the element.

  Considering these facts, the coloring of the glass substrate is considered to be caused by the oxygen deficiency in the environment to which the glass substrate is exposed when the ITO film is formed on the glass substrate. That is, in the process of forming the ITO film, since the vicinity of the glass substrate becomes an atmosphere having weak oxidizability, the reducible elements in the glass substrate are reduced, and thereby the glass substrate is considered to be colored.

  Based on the above considerations, in the present invention, in the initial stage of the ITO film formation process, the film formation atmosphere is set to an “oxygen-excess” condition as compared with the prior art. Thereby, the atmosphere in the vicinity of the glass substrate at the time of film formation becomes stronger oxidizing property, and the reduction of the reducible element in the glass substrate is suppressed. As a result, the coloring of the glass substrate can be suppressed.

  However, if the entire ITO film is formed under such “oxygen-excess” conditions, the resistance of the ITO film becomes high as described above, and the ITO film is used as an element electrode. It becomes impossible to do.

  Therefore, in the present invention, after the ITO film portion (hereinafter referred to as the “first ITO portion” 146) having been “highly oxidized” is formed by the film formation under the initial “oxygen-excess” condition. The film forming conditions are returned to, for example, normal conditions, an ITO film portion (hereinafter referred to as “second ITO portion” 148) is formed with a “low degree of oxidation”, and the entire ITO film is formed.

  When the ITO film 140 is formed by such a method, when the first ITO portion 146 forms the second ITO portion 148, it serves as a barrier for the reduction reaction of the reducible element contained in the glass substrate 110. Function. For this reason, even if the second ITO portion 148 is formed in a conventional oxygen-deficient environment, the reduction of the reducible element in the glass substrate 110 can be suppressed. As a result, the coloring of the glass substrate 110 is significantly suppressed.

  Further, since the second ITO portion 148 has higher conductivity than the first ITO portion 146, this can suppress an increase in resistance of the ITO film 140 as a whole.

  Therefore, in the translucent substrate 100 having the ITO film 140 configured as shown in FIG. 1, it is possible to obtain both effects of preventing the coloring of the glass substrate 110 and suppressing the increase in resistance of the ITO film 140.

The resistivity of the ITO film 140 may be, for example, less than 2.38 × 10 ⁻⁴ Ωcm.

  As described above, the ITO film 140 includes the first ITO portion 146 having a high degree of oxidation and the second ITO portion 148 having a low degree of oxidation, and the degrees of oxidation of both ITO films are different. Yes. Here, in the aspect of the change in the degree of oxidation from the first ITO portion 146 to the second ITO portion 148, the degree of oxidation of the first ITO portion 146 is lower than that of the second ITO portion 148. Not particularly limited.

  For example, the degree of oxidation of the ITO film 140 may vary continuously from the first surface 142 to the second surface 144, or it may vary discontinuously (eg, in steps), or You may change in the aspect which combined the continuous part and the discontinuous part. When the degree of oxidation changes continuously, the change may be linear or curvilinear. Alternatively, a third ITO portion with the lowest degree of oxidation may be present between the first ITO portion 146 and the second ITO portion 148.

  Furthermore, the expressions first ITO portion 146 and second ITO portion 148 are merely convenient and both need not be clearly distinguishable. That is, what is important in the first translucent substrate 100 is that the first surface 142 side of the ITO film 140 is in a state of higher degree of oxidation than the second surface 144 side.

  It should be noted that in the present application, the terms “degree of oxidation” and “degree of oxidation” of an ITO film are indicators that are used relatively to express the difference between two comparison targets. There is.

  The “oxidation degree” of the ITO film 140 can be relatively evaluated, for example, by performing X-ray photoelectron spectroscopy (XPS) analysis on each of the two comparison targets.

(Second translucent substrate)
Next, a second light-transmitting substrate according to one embodiment of the present invention will be described.

  FIG. 2 is a schematic cross-sectional view of a second light transmissive substrate according to an embodiment of the present invention.

  As shown in FIG. 2, the second translucent substrate 200 is basically configured in the same manner as the first translucent substrate 100. Therefore, in FIG. 2, the same reference numerals as those in FIG. 1 plus 100 are used for the same members as in FIG.

  However, the second translucent substrate 200 shown in FIG. 2 is different from the ITO film 140 in FIG. 1 in the configuration of the ITO film 240. That is, the ITO film 240 having the first surface 242 and the second surface 244 has a multilayer structure having at least two layers. For example, in FIG. 2, the ITO film 240 includes a first ITO layer 245 disposed on the side close to the glass substrate 210 and a second ITO layer 247 disposed on the side far from the glass substrate 210.

  The first ITO layer 245 has a higher degree of oxidation than the second ITO layer 247, and the second ITO layer 247 is more conductive than the first ITO layer 245. It is high.

  In the second light-transmitting substrate 200 having the ITO film 240 having such a configuration, both the prevention of coloring of the glass substrate 210 and the suppression of the increase in resistance of the ITO film 240 are performed as in the first light-transmitting substrate 100. It is clear that the effect of can be obtained.

  In the example of FIG. 2, the ITO film 240 has a two-layer structure, but the ITO film 240 may have a multilayer structure of three or more layers. In this case, the ITO film closest to the glass substrate is configured to have a higher degree of oxidation than the other ITO films.

  In the second light transmitting substrate 200 shown in FIG. 2, a coating layer may be provided between the glass substrate 210 and the ITO film 240.

  The first ITO layer 245 may have a thickness of 1 nm to 20 nm, for example. Similarly, the second ITO layer 247 may have a thickness of 1 nm to 500 nm, for example. The total thickness of the ITO film 240 may be in the range of 2 nm to 520 nm, for example.

Further, the resistivity of the entire ITO film 240 may be less than 2.38 × 10 ⁻⁴ Ωcm, for example.

(Third translucent substrate)
In the above, the structure and effect of this invention were demonstrated to the example of the translucent board | substrate comprised by the glass substrate, ITO film | membrane, and the coating layer installed arbitrarily. However, the present invention is not limited to such an embodiment.

  For example, recently, for the purpose of increasing the light extraction efficiency from a translucent substrate and an organic LED element, a scattering layer for scattering light is installed on the surface of a glass substrate for installing an ITO film. Has been proposed.

  Here, such a scattering layer is composed of, for example, a glass base material and a scattering material dispersed in the base material. Therefore, even when the scattering layer made of glass contains the above-mentioned “reducible element”, the scattering layer is colored when the ITO film is formed on the scattering layer. Problems can arise.

  Therefore, hereinafter, the configuration of another translucent substrate according to an embodiment of the present invention for significantly suppressing the problem of coloring of the scattering layer will be described.

  FIG. 3 is a schematic cross-sectional view of a third light transmissive substrate 300 according to an embodiment of the present invention.

  As shown in FIG. 3, the third light transmissive substrate 300 includes a glass substrate 310, a scattering layer 320, and an ITO film 340.

  In this embodiment, unlike the glass substrates 110 and 210 described above, the glass substrate 310 does not necessarily include the above-described reducible element.

  The scattering layer 320 includes a glass base material 321 having a first refractive index, and a plurality of scattering materials 324 having a second refractive index different from the base material 321 dispersed in the base material 321. Consists of. The scattering layer 320 (that is, the base material 321 and / or the scattering material 324) includes at least one element of bismuth (Bi), titanium (Ti), and tin (Sn), that is, a “reducible element”. .

  Although not shown in FIG. 3, a coating layer may be provided between the scattering layer 320 and the ITO film 340. Such a coating layer functions as an anti-etching barrier that prevents elution and deterioration of the glass substrate 310 when the ITO film 340 is patterned, for example. The coating layer is made of, for example, a metal oxide or a metal oxynitride. However, the coating layer is not an essential component and may be omitted as shown in FIG.

  The ITO film 340 functions as one electrode (anode) when a finished product, for example, an organic LED element, is formed from the third light transmitting substrate 300. The ITO film 340 has a first surface 342 on the side close to the glass substrate 310 and a second surface 344 on the side far from the glass substrate 310.

  The ITO film 340 has a multilayer structure, and has at least two layers of a first ITO layer 345 and a second ITO layer 347 as shown in FIG. The first ITO layer 345 is disposed closer to the scattering layer 320 than the second ITO layer 347.

  Similar to the ITO film 240 of the translucent substrate 200 shown in FIG. 2 described above, the first ITO layer 345 has a higher degree of oxidation than the second ITO layer 347. The ITO layer 347 has higher conductivity than the first ITO layer 345.

  The first ITO layer 345 may have a thickness of 1 nm to 20 nm, for example. Similarly, the second ITO layer 347 may have a thickness of 1 nm to 500 nm, for example. The total thickness of the ITO film 340 may be in the range of 2 nm to 520 nm, for example.

Further, the resistivity of the entire ITO film 340 may be, for example, less than 2.38 × 10 ⁻⁴ Ωcm.

  Here, the first ITO layer 345 is formed in an atmosphere of “oxygen-excess” than in the prior art. For this reason, it is possible to significantly suppress the reduction of the reducible element in the scattering layer 320 during the formation of the first ITO layer 345. On the other hand, the second ITO layer 347 is formed in an atmosphere with less oxygen, for example, in an atmosphere with low oxidizability equivalent to that of the prior art, as compared with the film formation conditions of the first ITO layer 345. However, since the first ITO layer 345 is present, that is, the first ITO layer 345 functions as a barrier layer, the second ITO layer 347 is formed even when the second ITO layer 347 is formed. The reduction reaction of the reducing element is suppressed.

  As a result, the first ITO layer 345 having a higher degree of oxidation than the second ITO layer 347 and higher conductivity than the first ITO layer 345 without causing the scattering layer 320 to be colored. An ITO film 340 having the second ITO layer 347 can be formed.

  From the above, also in the third translucent substrate 300 having the ITO film 340, it is possible to obtain both effects of preventing the scattering layer 320 from being colored and suppressing the increase in resistance of the ITO film 340.

  In the above, the structure and effect were demonstrated about the 3rd translucent board | substrate 300 of a type provided with a scattering layer. However, the configuration of the third translucent substrate having the scattering layer is not limited to this. For example, in a translucent substrate having a scattering layer, the ITO film may be a “single layer” like the ITO film 140 of FIG. In this case, as described above, the surface of the ITO film close to the scattering layer becomes the first ITO portion having a high degree of oxidation, and the surface side far from the scattering layer becomes the second ITO portion having a low degree of oxidation. Configured as follows.

(Organic LED element)
Next, with reference to FIG. 4, the organic LED element by one form of this invention is demonstrated.

  In FIG. 4, schematic sectional drawing of an example of the organic LED element by one form of this invention is shown.

  As shown in FIG. 4, an organic LED element 401 according to an embodiment of the present invention includes a glass substrate 410, a scattering layer 420, a first electrode (anode) layer 440, an organic light emitting layer 450, and a second electrode. A (cathode) layer 460 is laminated in this order.

  The glass substrate 410 has a role of supporting each layer constituting the organic LED element on the top. In the example of FIG. 4, the lower surface of the organic LED element 401 (that is, the exposed surface of the glass substrate 410) is the light extraction surface 470.

  The scattering layer 420 includes a glass base material 421 having a first refractive index, and a plurality of scattering materials 424 having a second refractive index different from the base material 421 and dispersed in the base material 421. Consists of.

  The scattering layer 420 has a role of effectively scattering the light generated from the organic light emitting layer 450 and reducing the amount of light totally reflected in the organic LED element 401. Therefore, in the organic LED element 401 having the configuration shown in FIG. 4, the amount of light emitted from the light extraction surface 470 can be improved.

  The scattering layer 420 includes the “reducible element” as described above.

  The first electrode layer 440 is made of an ITO film. On the other hand, the second electrode layer 460 is made of a metal such as aluminum or silver.

  In general, the organic light emitting layer 450 includes a light emitting layer and a plurality of layers such as an electron transport layer, an electron injection layer, a hole transport layer, and a hole injection layer.

  Although not shown in FIG. 4, in the organic LED element 401, a coating layer may be provided between the scattering layer 420 and the first electrode layer 440.

  The coating layer smoothes the surface of the scattering layer and facilitates the subsequent film formation process, and / or the elution or deterioration of the scattering layer during patterning of the first electrode layer, etc. It functions as an anti-etching barrier that prevents The coating layer is made of metal oxide or metal oxynitride.

  Here, the ITO film constituting the first electrode layer 440 may have a multilayer structure as described above. For example, in FIG. 4, the ITO film is composed of two layers, a first ITO layer 445 closer to the glass substrate 410 and a second ITO layer 447 farther from the glass substrate 410. In addition, the first ITO layer 445 has a higher degree of oxidation than the second ITO layer 447, and the second ITO layer 447 is more conductive than the first ITO layer 445. The nature is getting higher.

  Also in the organic LED element 401 including the first electrode layer 440 configured as described above, it is possible to obtain both effects of preventing the scattering layer 420 from being colored and suppressing the resistance increase of the first electrode layer 440.

  In FIG. 4, the portion from the glass substrate 410 to the first electrode layer 440 may be configured by the above-described translucent substrate 300 shown in FIG. 3.

  In the example of FIG. 4, the first electrode layer 440 includes two ITO films 445 and 447. However, the first electrode layer 440 may be composed of three or more ITO films. In this case, the ITO film closest to the glass substrate is configured to have a higher degree of oxidation than other ITO films.

  Alternatively, the first electrode layer 440 may be formed of a “single layer” like the ITO film 140 shown in FIG. In this case, as described above, the surface of the ITO film close to the scattering layer becomes the first ITO portion having a high degree of oxidation, and the surface side far from the scattering layer becomes the second ITO portion having a low degree of oxidation. Composed.

  Further, in the configuration of FIG. 4, the organic LED element 401 includes a scattering layer 420. However, in the organic LED element, the scattering layer 420 is not necessarily required and may be omitted. However, in the case of an organic LED element not including such a scattering layer, the glass substrate has a composition including a reducible element.

(About each component)
Next, the detail of each element which comprises the organic LED element 401 is demonstrated. It should be noted that some of the elements shown below can be used in the same manner in the light-transmitting substrates 100 to 300 shown in FIGS.

(Glass substrate 410)
The glass substrate 410 is made of a material having a high transmittance for visible light. Examples of the material of the glass substrate include inorganic glass such as alkali glass, non-alkali glass, and quartz glass. Examples of the plastic substrate material include polyester, polycarbonate, polyether, polysulfone, polyethersulfone, polyvinyl alcohol, and fluorine-containing polymers such as polyvinylidene fluoride and polyvinyl fluoride.

  When the organic LED element does not have the scattering layer 420, the glass substrate 410 contains a reducible element.

  Although the thickness of the glass substrate 410 is not specifically limited, For example, the range of 0.1 mm-2.0 mm may be sufficient. Considering strength and weight, the thickness of the glass substrate 410 is preferably 0.5 mm to 1.4 mm.

(Scattering layer 420)
The scattering layer 420 includes a base material 421 and a plurality of scattering materials 424 dispersed in the base material 421. The base material 421 has a first refractive index, and the scattering material 424 has a second refractive index different from that of the base material.

  The scattering layer 420 contains the aforementioned reducible element.

  Note that the amount of the scattering material 424 in the scattering layer 420 is preferably decreased from the inside of the scattering layer 420 to the outside, and in this case, highly efficient light extraction can be realized.

  The base material 421 is made of glass, and an inorganic glass such as soda lime glass, borosilicate glass, alkali-free glass, and quartz glass is used as the glass material.

  The scattering material 424 includes, for example, bubbles, precipitated crystals, material particles different from the base material, phase separation glass, and the like. A phase-separated glass refers to a glass composed of two or more types of glass phases.

  The difference between the refractive index of the base material 421 and the refractive index of the scattering material 424 is preferably large. For this purpose, it is preferable to use high refractive index glass as the base material 421 and use bubbles as the scattering material 424. .

Because of the high refractive index glass for the base material 421, one or more components of P ₂ O ₅ , SiO ₂ , B ₂ O ₃ , GeO ₂ , and TeO ₂ are selected as the network former. As high refractive index components, TiO ₂ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , ZnO, BaO, PbO, and Sb ₂ One or more components of O ₃ may be selected. Furthermore, in order to adjust the characteristics of the glass, alkali oxides, alkaline earth oxides, fluorides, and the like may be added within a range that does not affect the refractive index.

Accordingly, examples of the glass system constituting the base material 421 include B ₂ O ₃ —ZnO—La ₂ O ₃ system, P ₂ O ₅ —B ₂ O ₃ —R ′ ₂ O—R ”O—TiO ₂ —. Nb ₂ O ₅ —WO ₃ —Bi ₂ O ₃ system, TeO ₂ —ZnO system, B ₂ O ₃ —Bi ₂ O ₃ system, SiO ₂ —Bi ₂ O ₃ system, SiO ₂ —ZnO system, B ₂ O ₃ -ZnO _system, like P ₂ O 5 -ZnO system. here, R 'is an alkali metal element, R "represents an alkaline earth metal element. In addition, the above material system is only an example, and if it is the structure which satisfy | fills the said conditions, the material to be used will not be restricted especially.

  By adding a colorant to the base material 421, the color of light emission can be changed. As the colorant, transition metal oxides, rare earth metal oxides, metal colloids, and the like can be used alone or in combination.

(Coating layer)
Although not shown in FIG. 4, a coating layer may be provided between the scattering layer 420 and the first electrode layer 440.

  The covering layer is at least partially formed of metal oxide or metal oxynitride. The metal species constituting the metal oxide or metal oxynitride is not particularly limited, but the metal species may include, for example, titanium, indium, tin, tungsten, tantalum, and / or niobium.

The covering layer may further contain silicon oxide (SiO ₂ ).

  For example, the coating layer may be a layer composed of a mixture of titanium oxide and silicon oxide. In this case, the ratio of titanium oxide and silicon oxide is not particularly limited, but the ratio between the two (titanium oxide: silicon oxide) may be, for example, in the range of 80:20 to 20:80. . In particular, the ratio of titanium oxide: silicon oxide is preferably in the range of 75:25 to 40:60 by weight.

  In order to further improve the extraction efficiency, the refractive index of the coating layer is preferably lower than that of the first electrode layer 440. Specifically, the difference between the refractive index of the coating layer and the refractive index of the scattering layer 420 is preferably 0.2 or less, more preferably 0.13 or less, and more preferably 0.11 or less.

  The film thickness of the coating layer is not particularly limited. The film thickness of the coating layer may be in the range of 100 nm to 500 μm, for example.

  The coating layer may be formed by either a wet coating method or a dry coating method.

(First electrode layer 440)
As described above, the first electrode layer 440 is made of an ITO film. Further, as described above, the ITO film may be composed of two layers of the first ITO layer 445 closer to the glass substrate 410 and the second ITO layer 447 farther from the glass substrate 410. In this case, the first ITO layer 445 is configured to have a higher degree of oxidation than the second ITO layer 447, and the second ITO layer 447 is compared to the first ITO layer 445. It is comprised so that electroconductivity may become high.

  The thickness of the first ITO layer 445 is not particularly limited, but is preferably in the range of 1 nm to 20 nm, for example. The thickness of the second ITO layer 447 is not particularly limited, but is preferably in the range of 1 nm to 500 nm, for example.

  Note that the ITO film constituting the first electrode layer 440 may be composed of three or more layers. Alternatively, as shown in FIG. 1 described above, the ITO film changes in the degree of oxidation continuously or discontinuously from the first surface 442 to the second surface 444 of the first electrode layer 440. It may be composed of a single layer that (decreases).

  The total thickness of the first electrode layer 440 is preferably 50 nm or more.

  The refractive index of the first electrode layer 440 is in the range of 1.65 to 2.2. Note that the refractive index of the first electrode layer 440 is preferably determined in consideration of the refractive index of the base material 421 included in the scattering layer 420 and the refractive index of the second electrode layer 460. In consideration of waveguide calculation, the reflectance of the second electrode layer 460, and the like, the difference in refractive index between the first electrode layer 440 and the base material 421 is preferably 0.2 or less.

(Organic light emitting layer 450)
The organic light emitting layer 450 is a layer having a light emitting function, and is usually composed of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. However, it is obvious to those skilled in the art that the organic light emitting layer 450 does not necessarily have all of the other layers as long as it has a light emitting layer. In a normal case, the refractive index of the organic light emitting layer 450 is in the range of 1.7 to 1.8.

  The hole injection layer preferably has a small difference in ionization potential in order to lower the hole injection barrier from the first electrode layer 440. When the charge injection efficiency from the electrode to the hole injection layer is increased, the driving voltage of the organic LED element 401 is decreased, and the charge injection efficiency is increased.

As the material of the hole injection layer, a high molecular material or a low molecular material is used. Among the polymer materials, polyethylene dioxythiophene (PEDOT: PSS) doped with polystyrene sulfonic acid (PSS) is often used, and among the low molecular materials, phthalocyanine-based copper phthalocyanine (CuPc) is widely used. .
The hole transport layer serves to transport holes injected from the hole injection layer to the light emitting layer. Examples of the hole transport layer include a triphenylamine derivative, N, N′-bis (1-naphthyl) -N, N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPD), N , N′-diphenyl-N, N′-bis [N-phenyl-N- (2-naphthyl) -4′-aminobiphenyl-4-yl] -1,1′-biphenyl-4,4′-diamine ( NPTE), 1,1′-bis [(di-4-tolylamino) phenyl] cyclohexane (HTM2), and N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′- Diphenyl-4,4′-diamine (TPD) or the like is used.

The thickness of the hole transport layer is, for example, in the range of 10 nm to 150 nm. The voltage of the organic LED element can be lowered as the thickness of the hole transport layer is reduced, but it is usually in the range of 10 nm to 150 nm due to the problem of short circuit between electrodes.
The light emitting layer has a role of providing a field where the injected electrons and holes are recombined. As the organic light emitting material, a low molecular weight or high molecular weight material is used.

  Examples of the light emitting layer include tris (8-quinolinolato) aluminum complex (Alq3), bis (8-hydroxy) quinaldine aluminum phenoxide (Alq′2OPh), and bis (8-hydroxy) quinaldine aluminum-2,5- Dimethylphenoxide (BAlq), mono (2,2,6,6-tetramethyl-3,5-heptanedionate) lithium complex (Liq), mono (8-quinolinolato) sodium complex (Naq), mono (2, 2,6,6-tetramethyl-3,5-heptanedionate) lithium complex, mono (2,2,6,6-tetramethyl-3,5-heptanedionate) sodium complex and bis (8-quinolinolate) Metal complexes of quinoline derivatives such as calcium complex (Caq2), tetraphenyl butadiene, phenyl key Kudrin (QD), anthracene, perylene, as well as fluorescent substance such as coronene.

As the host material, a quinolinolate complex may be used, and in particular, an aluminum complex having 8-quinolinol and a derivative thereof as a ligand may be used.
The electron transport layer serves to transport electrons injected from the electrode. Examples of the electron transport layer include quinolinol aluminum complex (Alq3), oxadiazole derivatives (for example, 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (END), and 2- ( 4-t-butylphenyl) -5- (4-biphenyl))-1,3,4-oxadiazole (PBD), triazole derivatives, bathophenanthroline derivatives, silole derivatives, and the like.
The electron injection layer is configured by, for example, providing a layer doped with an alkali metal such as lithium (Li) or cesium (Cs) at the interface with the second electrode layer 460.

(Second electrode layer 460)
For the second electrode layer 460, a metal having a low work function or an alloy thereof is used. The second electrode layer 460 may be, for example, an alkali metal, an alkaline earth metal, a metal belonging to Group 3 of the periodic table, or the like. For the second electrode layer 460, for example, aluminum (Al), magnesium (Mg), or an alloy thereof is used.

Also, a laminated electrode in which aluminum (Al) is deposited on a thin film of aluminum (Al), magnesium silver (MgAg), lithium fluoride (LiF), or lithium oxide (Li ₂ O) may be used. good. Furthermore, a laminated film of calcium (Ca) or barium (Ba) and aluminum (Al) may be used.

(Method for Manufacturing Translucent Substrate According to One Embodiment of the Present Invention)
Next, an example of a method for manufacturing a light-transmitting substrate according to an embodiment of the present invention is described with reference to the drawings. Here, as an example, the manufacturing method will be described using the configuration of the light-transmitting substrate 300 illustrated in FIG. 3 as an example. However, a part of the following description can be similarly applied to the method for manufacturing the translucent substrates 100 and 200 shown in FIGS.

  FIG. 5 shows a schematic flow chart in manufacturing a light-transmitting substrate according to an embodiment of the present invention.

As shown in FIG. 5, the manufacturing method of this translucent substrate is:
(A) A step of installing a scattering layer having a base material made of glass and a plurality of scattering materials dispersed in the base material on a glass substrate, wherein the scattering layer is Bi (bismuth), Including at least one element selected from the group consisting of Ti (titanium) and Sn (tin) (step S110);
(B) A step of forming an ITO film on the scattering layer, wherein the ITO film has a higher degree of oxidation on the side closer to the glass substrate than on the side farther from the glass substrate. A film forming step (step S120)
Have Hereinafter, each step will be described in detail. In the following description, the reference numerals shown in FIG. 3 are used as reference numerals for the respective members for the sake of clarity.

(Step S110)
First, the glass substrate 310 is prepared. Next, a scattering layer 320 containing a reducible element is formed on the glass substrate 310.

  The method for forming the scattering layer 320 is not particularly limited, but here, a method for forming the scattering layer 320 by the “frit paste method” will be particularly described. However, it will be apparent to those skilled in the art that the scattering layer 320 may be formed by other methods.

  In the frit paste method, a paste containing a glass material called a frit paste is prepared (preparation process), this frit paste is applied to the surface of the substrate to be installed, patterned (pattern formation process), and the frit paste is then baked. This is a method of forming a desired glass film on the surface of the substrate to be installed by performing (firing process). Hereinafter, each process will be briefly described.

(Preparation process)
First, a frit paste containing glass powder, resin, solvent and the like is prepared.

  The glass powder is composed of a material that finally forms the base material 321 of the scattering layer 320. The composition of the glass powder is not particularly limited as long as desired scattering characteristics can be obtained, and the glass powder can be frit pasted and fired. However, in the present invention, the scattering layer contains a reducible element.

The composition of the glass powder, for _example, 20 to 30 _mol% of _{P 2 O 5, B 2 O} 3 to 3~14mol%, 10~20mol% of _Bi 2 _{O 3,} a _{TiO 2 3~15mol%, Nb 2 O} 5 10 to 20 mol%, WO ₃ to 5 to 15 mol%, the total amount of Li ₂ O, Na ₂ O and K ₂ O is 10 to 20 mol%, and the total amount of the above components is 90 mol% or more. May be. Further, SiO ₂ is _0~30mol%, B 2 _{O 3} is 10~60mol%, ZnO is 0~40mol%, _Bi 2 _{O 3} is _0~40mol%, P 2 _{O 5} is 0~40mol%, alkali metal oxide A thing is 0-20 mol%, and the total amount of the above component may be 90 mol% or more. The particle size of the glass powder is, for example, in the range of 1 μm to 100 μm.

  In order to control the thermal expansion characteristics of the finally obtained scattering layer, a predetermined amount of filler may be added to the glass powder. For example, particles such as zircon, silica, or alumina are used as the filler, and the particle size is usually in the range of 0.1 μm to 20 μm.

  Examples of the resin include ethyl cellulose, nitrocellulose, acrylic resin, vinyl acetate, butyral resin, melamine resin, alkyd resin, and rosin resin. In addition, when a butyral resin, a melamine resin, an alkyd resin, and a rosin resin are added, the strength of the frit paste coating film is improved.

  A solvent has a role which melt | dissolves resin and adjusts a viscosity. Examples of the solvent include ether solvents (butyl carbitol (BC), butyl carbitol acetate (BCA), dipropylene glycol butyl ether, tripropylene glycol butyl ether, butyl cellosolve), alcohol solvents (α-terpineol, pine oil). , Ester solvents (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate), phthalate esters solvents (DBP (dibutyl phthalate), DMP (dimethyl phthalate), DOP (dioctyl phthalate)) is there. Mainly used are α-terpineol and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate). DBP (dibutyl phthalate), DMP (dimethyl phthalate), and DOP (dioctyl phthalate) also function as a plasticizer.

  In addition, a surfactant may be added to the frit paste to adjust viscosity and promote frit dispersion. Moreover, you may use a silane coupling agent for surface modification.

  Next, these raw materials are mixed to prepare a frit paste in which glass raw materials are uniformly dispersed.

(Pattern formation process)
Next, the frit paste prepared by the above-described method is applied on the glass substrate 310 and patterned. The application method and the patterning method are not particularly limited. For example, a frit paste may be pattern printed on the glass substrate 310 using a screen printer. Alternatively, a doctor blade printing method or a die coat printing method may be used.

  Thereafter, the frit paste film is dried.

(Baking process)
Next, the frit paste film is baked. Usually, firing is performed in two steps. In the first step, the resin in the frit paste film is decomposed and disappeared, and in the second step, the glass powder is softened and sintered.

  The first step is performed by maintaining the frit paste film in a temperature range of 200 ° C. to 400 ° C. in an air atmosphere. However, the processing temperature varies depending on the resin material contained in the frit paste. For example, when the resin is ethyl cellulose, the treatment temperature may be about 350 ° C. to 400 ° C., and when the resin is nitrocellulose, the treatment temperature may be about 200 ° C. to 300 ° C. The processing time is usually about 30 minutes to 1 hour.

  The second step is performed by maintaining the frit paste film in the temperature range of the softening temperature ± 30 ° C. of the glass powder contained in the atmosphere. The processing temperature is, for example, in the range of 450 ° C to 600 ° C. Further, the processing time is not particularly limited, but is, for example, 30 minutes to 1 hour.

  After the second step, the glass powder is softened and sintered, and the base material 321 of the scattering layer 320 is formed. In addition, the scattering material 324 uniformly dispersed in the base material 321 is obtained by the scattering material encapsulated in the frit paste film, for example, due to the bubbles present therein.

  Thereafter, the scattering layer 320 can be formed by cooling the glass substrate 310. In addition, the thickness of the scattering layer 320 finally obtained may be in the range of 5 μm to 50 μm.

  After the scattering layer 320 is formed on the glass substrate 310, a coating layer is formed on the scattering layer 320 if necessary.

  The coating layer is formed by, for example, a dry coating method. Alternatively, the coating layer may be formed by, for example, a wet coating method. The type of the wet coating method is not particularly limited, and for example, the coating layer may be formed using a sol-gel solution containing an organometallic solution and organometallic particles.

(Step S120)
Next, an ITO film 340 is formed on the scattering layer 320 (if there is a coating layer).

  The installation method of the ITO film 340 is not particularly limited, and the ITO film 340 may be installed by a film formation method such as a sputtering method, a vapor deposition method, and a vapor phase film formation method.

  Hereinafter, as an example, a method for forming the ITO film 340 by sputtering will be described.

  When the ITO film 340 is formed by sputtering, the ITO film 340 includes a first film formation step for forming the first ITO layer 345 and a second film formation for forming the second ITO layer 347. The film formation process is performed.

(I First film formation step)
Generally, when forming an ITO film by sputtering, a target made of an alloy of metallic indium and metallic tin or an ITO target is used.

Power density of plasma will vary depending on size of the apparatus, for example, in the range of ^{0.2W / cm 2 ~3W / cm 2} .

  Further, a mixed gas of an inert gas and oxygen is used as the sputtering gas.

  In the manufacturing method according to an embodiment of the present invention, the first ITO layer 345 is formed in the first film forming step under an atmosphere having a stronger oxidizing property than that of the prior art, that is, under the condition of “oxygen excess”.

Here, in the present application, the ratio R (vol% · cm ² / W) of the oxygen partial pressure P _O2 (vol%) of the sputtering gas to the plasma power density P _d (W / cm ² ) for the following reason, that is, R = _PO2 / _Pd is used to define the oxidizability of the deposition environment.

That is, for example, the amount of oxygen contained in the sputtering gas varies depending on various film forming conditions such as the scale and type of the sputtering apparatus and the power of the plasma. Therefore, it is difficult to simply represent the oxidizability of the film forming environment by the oxygen partial pressure in the sputtering gas. However, when the index R (vol% · cm ² / W) (R = P _{O 2} / P _d ) as in the present application is used, the influence of the variable factors as described above is standardized, and the film formation environment is oxidized. Can be compared more appropriately.

According to the above definition, it can be said that the larger the index R (vol% · cm ² / W), the more the environment is more oxidizing and the “oxygen-excess” condition. The index R (vol% · cm ² / W) is preferably larger than 1.03 (vol% · cm ² / W), more preferably 1.5 (vol% · cm ² / W) or more. preferable. The index R (vol% · cm ² / W) is, for example, about 1.6 or more, or about 2 or more.

  By forming the first ITO layer 345 under such “oxygen-excess” conditions, it is possible to significantly suppress the reduction of the reducible element in the scattering layer 320 during the sputtering process. it can. Further, the first ITO layer 345 having a high degree of oxidation can be formed on the scattering layer 320 by performing sputtering film formation under “oxygen-excess” conditions.

(Ii Second Film Formation Step)
Next, a second ITO layer 347 is formed on the first ITO layer 345.

The second ITO layer 347 has a lower oxidization condition than the film formation environment selected in the first film formation process, that is, from the index R (vol% · cm ² / W) in the first film formation process. The film is formed in an environment showing a small index R (vol% · cm ² / W). For example, the second ITO layer 347 may be formed under conditions that are generally employed when forming a conventional ITO film.

In the second film formation step, the index R (vol% · cm ² / W) is preferably 1.03 or less.

  Here, when the second ITO layer 347 is formed, the first ITO layer 345 having a high degree of oxidation is already formed on the scattering layer 320. For this reason, the barrier effect of the first ITO layer 345 can suppress the reduction of the reducible element contained in the scattering layer 320 during the formation of the second ITO layer 347.

  Therefore, the second ITO layer 347 can be formed without causing the scattering layer 320 to be colored even in the second film formation step.

  Through the first film formation step and the second film formation step as described above, the ITO film 340 having the first ITO layer 345 and the second ITO layer 347 can be formed.

  Here, since the second ITO layer 347 is formed under a condition in which the index R is smaller (that is, a condition with less oxidization), the conductivity of the film is higher than that of the first ITO layer 345. Can be increased. Therefore, the resistivity of the ITO film 340 can be reduced as compared with the case where the entire ITO film 340 is configured by the first ITO layer 345 in a state of high oxidation.

For example, the resistivity of the entire ITO film 340 can be set to a value comparable to that of an ITO film formed by a conventional method, for example, about 1.5 × 10 ⁻⁴ Ωcm.

  In this way, the first ITO layer 345 having a higher degree of oxidation than the second ITO layer 347, and the second ITO layer 347 having a higher conductivity than the first ITO layer 345, , An ITO film 340 can be formed.

  Thereafter, the ITO film 340 may be patterned by an etching process or the like.

  Through the above steps, the light-transmitting substrate 300 including the glass substrate 310, the scattering layer 320, and the ITO film 340 can be manufactured.

  In addition, when manufacturing an organic LED element from the translucent board | substrate 300, what is necessary is just to form an organic light emitting layer and a 2nd electrode layer further in order.

  For example, an organic light emitting layer may be provided on the first ITO layer 340 by vapor deposition and / or coating. In addition, the second electrode layer 460 may be provided on the organic light emitting layer by, for example, vapor deposition, sputtering, vapor deposition, or the like.

  In the above description, the manufacturing method according to an embodiment of the present invention is described by taking as an example the case where an ITO film 340 having a multilayer structure having two ITO films 345 and 347 that can be clearly identified is formed. did. The ITO film 340 having such a multi-layer structure is easily formed when the film forming process is temporarily interrupted before changing the film forming conditions such as the plasma density and the oxygen partial pressure.

  However, the manufacturing method of the present invention is not limited to this, and a single layer structure ITO film 140 having two portions 146 and 148 having different characteristics as shown in FIG. It may be filmed. The ITO film 140 having such a single layer structure can be configured by, for example, continuously performing film formation without interrupting the film formation process when changing the film formation conditions.

  In the above description, the ITO film 340 is formed by sputtering. However, this is merely an example, and the ITO film 340 may be formed by other film forming methods.

  In the above, the subject of this invention and the thought for solving it were demonstrated to the example of the translucent board | substrate and organic LED element which are comprised by installing an ITO film | membrane on a glass substrate.

  However, the application range of the present invention is not limited to such a translucent substrate and organic LED element.

For example, for the electrode layer of the translucent substrate, in addition to the ITO film, various conductive oxides such as IZO (Indium Zinc Oxide), AZO (Al-doped ZnO), SnO ₂ , Ta-doped SnO ₂ and Ti-doped In ₂ O ₃ or the like can be used. Such a conductive oxide is usually formed on a glass substrate under the same conditions as those for forming an ITO film, that is, in an environment where oxygen deficiency is likely to occur. Therefore, the same problem of coloring the glass substrate can occur when various conductive oxides other than the ITO film are formed. The problem can be solved by applying the present invention to such a problem.

  Next, examples of the present invention will be described.

(Preliminary test)
An ITO film was formed on a glass substrate by the following method, and the characteristics of the obtained samples were evaluated.

(Example 1)
An ITO film was formed on a glass substrate containing Bi (bismuth) using an ITO target and a sputtering apparatus. The concentration of Bi in the glass substrate is 20 mol%.

The glass substrate temperature was heated to 380 ° C. Moreover, the mixed gas of argon gas and oxygen was used as plasma gas. The oxygen concentration (P _O2 ) was 0.79 vol%.

The plasma density (P _d ) during film formation was 0.25 W / cm ² . Therefore, the index R (vol% · cm ² / W) (R = P _{O 2} / P _d ) is 3.20 (vol% · cm ² / W). The thickness of the ITO film was 30 nm (target).

  After the film formation, a glass sample having an ITO film (hereinafter referred to as “sample 1”) was obtained.

(Example 2)
A glass sample having an ITO film (hereinafter referred to as “sample 2”) was produced in the same manner as in Example 1.

However, in Example 2, the oxygen concentration (P _O2 ) was 0.79 vol%, and the plasma density (P _d ) during film formation was 0.99 W / cm ² . Therefore, the index R (vol% · cm ² / W) is 0.80 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other conditions are the same as in Example 1.

  As a result, Sample 2 was obtained.

(Example 3)
A glass sample having an ITO film (hereinafter referred to as “sample 3”) was produced in the same manner as in Example 1.

However, in Example 3, the oxygen concentration (P _O2 ) was 1.57 vol%, and the plasma density (P _d ) during film formation was 0.99 W / cm ² . Therefore, the index R (vol% · cm ² / W) is 1.59 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other conditions are the same as in Example 1.

  Thereby, sample 3 was obtained.

(Example 4)
A glass sample having an ITO film (hereinafter referred to as “sample 4”) was produced in the same manner as in Example 1.

However, in Example 4, the oxygen concentration (P _O2 ) was 1.96 vol%, and the plasma density (P _d ) during film formation was 0.99 W / cm ² . Therefore, the index R (vol% · cm ² / W) is 1.98 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other conditions are the same as in Example 1.

  As a result, Sample 4 was obtained.

(Example 5)
A glass sample having an ITO film (hereinafter referred to as “sample 5”) was produced in the same manner as in Example 1.

However, in Example 5, the oxygen concentration (P _O2 ) was 0.60 vol%, and the plasma density (P _d ) during film formation was 1.53 W / cm ² . Therefore, the index R (vol% · cm ² / W) is 0.39 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other conditions are the same as in Example 1.

  As a result, Sample 5 was obtained.

(Example 6)
A glass sample having an ITO film (hereinafter referred to as “sample 6”) was produced in the same manner as in Example 1.

However, in Example 6, the oxygen concentration (P _O2 ) was 0.79 vol%, and the plasma density (P _d ) during film formation was 1.53 W / cm ² . Therefore, the index R (vol% · cm ² / W) is 0.52 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other conditions are the same as in Example 1.

  Thereby, Sample 6 was obtained.

(Example 7)
A glass sample having an ITO film (hereinafter referred to as “sample 7”) was produced in the same manner as in Example 1.

However, in Example 7, the oxygen concentration (P _O2 ) was 1.57 vol%, and the plasma density (P _d ) during film formation was 1.53 W / cm ² . Therefore, the index R (vol% · cm ² / W) is 1.03 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other conditions are the same as in Example 1.

  As a result, Sample 7 was obtained.

(Example 8)
A glass sample having an ITO film (hereinafter referred to as “sample 8”) was produced in the same manner as in Example 1.

However, in Example 8, the oxygen concentration (P _O2 ) was 2.34 vol%, and the plasma density (P _d ) during film formation was 1.53 W / cm ² . Therefore, the index R (vol% · cm ² / W) is 1.53 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other conditions are the same as in Example 1.

  As a result, Sample 8 was obtained.

  Table 1 below collectively shows the manufacturing conditions of Samples 1 to 8.

（評価）
前述のように作製した各サンプル１〜８を用いて、着色評価試験、吸収係数の測定、ホール抵抗率測定、および消衰係数測定を行った。

(Evaluation)
Using each of the samples 1 to 8 produced as described above, a color evaluation test, an absorption coefficient measurement, a Hall resistivity measurement, and an extinction coefficient measurement were performed.

  The results of each evaluation test are collectively shown in Table 1 above.

The color evaluation test was performed according to the following procedure:
(1) Wet etching a sample on which ITO is formed with an iron chloride aqueous solution;
(2) The spectral absorption of the sample is evaluated with a spectroscopic device (Lambda 950, manufactured by Perkin Elmer);
(3) If the absorption amount is larger than the absorption of the substrate glass, it is determined that the substrate is colored during the ITO film forming process.

  As a result of the evaluation, it was confirmed that samples 1, 3, 4, and 8 were not colored, but samples 2, 5, 6, and 7 were colored.

  When the same measurement was performed using the glass substrate before the ITO film was installed, the amount of absorption a at a wavelength of 550 nm of the glass substrate was about 5.1%.

Further, from the comparison of the index ^{R (vol% · cm 2 /} W) , but the index ^{R (vol% · cm 2 /} W) coloring occurs in ^{1.03 (vol% · cm 2 /} W) or less, index It was found that no coloring occurs when R (vol% · cm ² / W) is 1.53 (vol% · cm ² / W) or more.

From this, as a condition at the time of forming the first ITO layer (part where the degree of oxidation is higher), the index R (vol% · cm ² / W) is larger than 1.03, and the index R (vol) % · Cm ² / W) is preferably 1.53 or more.

  Next, the Hall resistivity of each sample 1-8 was measured with the Hall resistivity measuring device.

As a result of the measurement, it is understood that the Hall resistivity tends to be smaller as the index R (vol% · cm ² / W) is smaller. This is because when the index R (vol% · cm ² / W) is small, that is, when film formation is performed in an environment with low oxidizability, the degree of oxidation of the formed ITO film becomes low, and the resistance of the ITO film decreases. This suggests a decline, and is consistent with the considerations described so far. Therefore, it can be said that the index R (vol% · cm ² / W) is preferably as low as possible from the viewpoint of resistance suppression.

  Next, the extinction coefficient k of each sample 1-8 was measured. The extinction coefficient k was measured by ellipsometry.

  As a result of the measurement, the extinction coefficient k was relatively small in Samples 1, 3, 4 and 8 in which coloring did not occur (maximum 0.0051). On the other hand, in samples 2, 5, 6 and 7 in which coloring occurred, the extinction coefficient k was relatively large (at least 0.0056).

From this, it was found that the extinction coefficient k can be used as a value related to the index R (vol% · cm ² / W). That is, when the index R (vol% · cm ² / W) is large, the extinction coefficient k tends to be small, and when the index R (vol% · cm ² / W) is small, the extinction coefficient k is large. It can be said that there is a tendency.

  In addition, it can be said that the first ITO layer (the portion where the degree of oxidation is higher) is preferably formed so that the extinction coefficient k is smaller than 0.0056, in particular, 0.0051 or less.

  From the results of the above preliminary tests, an approximate relationship between the parameters during film formation and the properties of the obtained ITO film was grasped.

(Film formation test)
(Preparation of sample A)
Next, using the same glass substrate as that used in the preliminary test, an ITO film having a two-layer structure was formed on this surface to prepare a sample (referred to as “sample A”).

First, a first ITO layer was formed by sputtering on a glass substrate in an environment having a plasma density (P _d ) of 0.25 W / cm ² and an oxygen concentration (P _O2 ) of 0.79 vol% (first Film formation). The index R (vol% · cm ² / W) during the first film formation is 3.20 (vol% · cm ² / W). The thickness of the first ITO layer was 10 nm (target). Other sputtering conditions are the same as in the preliminary test.

  After the completion of the first film formation, the film formation was interrupted and the film formation conditions were changed.

Next, a second ITO layer was formed by sputtering on the first ITO layer in an environment having a plasma density (P _d ) of 1.53 W / cm ² and an oxygen concentration (P _O2 ) of 0.60 vol%. (Second film formation). The index R (vol% · cm ² / W) during the second film formation is 0.39 (vol% · cm ² / W). Note that the thickness of the second ITO layer was 150 nm (target).

  Thereby, an ITO film having a two-layer structure having a total thickness of about 160 nm was formed.

(Preparation of sample B)
Using the same glass substrate as that used in the preliminary test, an ITO film having a single-layer structure was formed on this surface to prepare a sample (referred to as “sample B”).

The ITO film was formed by sputtering on a glass substrate in an environment with a plasma density (P _d ) of 1.53 W / cm ² and an oxygen concentration (PO ₂ ) of 2.34 vol%. The index R (vol% · cm ² / W) during film formation is 1.53 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other sputtering conditions are the same as in the preliminary test.

(Preparation of sample C)
Using the same glass substrate as that used in the preliminary test, an ITO film having a single-layer structure was formed on this surface to prepare a sample (referred to as “sample C”).

The ITO film was formed by sputtering on a glass substrate in an environment with a plasma density (P _d ) of 1.53 W / cm ² and an oxygen concentration (P _O2 ) of 0.60 vol%. The index R (vol% · cm ² / W) during film formation is 0.39 (vol% · cm ² / W). The thickness of the ITO film was 150 nm (target). Other sputtering conditions are the same as in the preliminary test.

  Table 2 summarizes the film forming conditions of Samples A to C.

（評価）
このようにして得られたサンプルＡ、Ｂ、Ｃを用いて、前述の方法により、着色評価試験、吸収係数の測定、ホール抵抗率測定、および消衰係数測定を行った。

(Evaluation)
Using the samples A, B, and C thus obtained, a coloring evaluation test, an absorption coefficient measurement, a Hall resistivity measurement, and an extinction coefficient measurement were performed by the above-described methods.

  The measurement results are shown in Table 2 above.

  As shown in Table 2, as a result of the coloring evaluation test, it was confirmed that the sample A was not colored. As a result of measuring the amount of absorption, the amount of absorption a of sample A was 5.23%. The value of the absorption amount a is close to the absorption amount a of the glass substrate, and the absorption amount a obtained in the sample group (samples 1, 3, 4, and 8) in which coloring did not occur in the preliminary test described above. It almost agrees with the value of.

  Similarly, in Sample B, coloring was not caused (absorption amount a = 5.43%).

  On the other hand, Sample C had an absorption of 9.47% and was colored.

Next, as a result of measuring the Hall resistivity, the Hall resistivity of Sample A was 1.30 × 10 ⁻⁴ Ωcm.

This value corresponds to Sample 5 (index R = 0.39 vol% · cm ² / W) and Sample 6 (index R = 0.52 vol% · cm ² ) manufactured in an atmosphere with weak oxidizability in the preliminary test described above. / W) comparable to the measured Hall resistivity. Therefore, in Sample A, the increase in the resistance of the ITO film is significantly suppressed even though the first film formation was performed under an oxygen-excess condition (index R = 3.20 vol% · cm ² / W). I found out.

On the other hand, the Hall resistivity of Sample B was 2.38 × 10 ⁻⁴ Ωcm, and it was confirmed that the ITO film resistance increase cannot be avoided by the method of forming the ITO film as in Sample B. Sample C had a Hall resistivity of 1.26 × 10 ⁻⁴ Ωcm, but absorption occurred.

  Thus, it has been found that the occurrence of coloring of the glass substrate can be suppressed by sequentially forming the first ITO layer having a high degree of oxidation and the second ITO layer having a low degree of oxidation. Moreover, it was confirmed that the increase in resistance of the entire ITO film can be significantly suppressed by forming the ITO film having such a configuration.

  The present invention can be applied to organic LED elements used in light emitting devices and the like.

DESCRIPTION OF SYMBOLS 100 1st translucent board | substrate 110 Glass substrate 140 ITO film 142 1st surface 144 2nd surface 146 1st ITO part 148 2nd ITO part 200 2nd translucent board | substrate 210 Glass substrate 240 ITO film | membrane 242 1st surface 244 2nd surface 245 1st ITO layer 247 2nd ITO layer 300 3rd translucent substrate 310 Glass substrate 320 Scattering layer 321 Base material 324 Scattering substance 340 ITO film 342 1st surface 344 Second surface 345 First ITO layer 347 Second ITO layer 401 Organic LED element 410 Glass substrate 420 Scattering layer 421 Base material 424 Scattering substance 440 First electrode layer 442 First surface 444 Second surface 445 First ITO layer 447 Second ITO layer 450 Organic light emitting layer 460 Second electrode layer 4 0 light extraction surface

Claims (19)

A method for producing a light-transmitting substrate comprising a glass substrate, a scattering layer formed on the glass substrate, and an ITO film formed on the scattering layer,
A step of disposing a scattering layer having a base material made of glass and a plurality of scattering materials dispersed in the base material on a glass substrate, wherein the scattering layer includes Bi (bismuth), Ti (titanium) And at least one element selected from the group consisting of Sn (tin);
Forming an ITO film on the scattering layer;
Have
The manufacturing method, wherein the ITO film is formed such that the side closer to the glass substrate has a higher degree of oxidation than the side far from the glass substrate. A method for producing a translucent substrate having a glass substrate and an ITO film on the glass substrate,
Providing a glass substrate containing at least one element selected from the group consisting of Bi (bismuth), Ti (titanium), and Sn (tin);
Forming an ITO film on the glass substrate;
Have
The manufacturing method, wherein the ITO film is formed such that the side closer to the glass substrate has a higher degree of oxidation than the side far from the glass substrate.   The step of forming the ITO film forms the ITO film in which the degree of oxidation decreases continuously or discontinuously from the side closer to the glass substrate toward the side farther from the glass substrate. 3. The production method according to 1 or 2. The step of forming the ITO film includes the step of forming the ITO film by sputtering.
In the first stage of film formation, the ratio R (vol% · cm ² / W) of the oxygen partial pressure P _O2 (vol%) to the plasma power density P _d (W / cm ² ) compared to the stage at the end of film formation. ) (R = _PO2 / _Pd ) is large, The manufacturing method according to any one of claims 1 to 3. 5. The manufacturing method according to claim 4, wherein a ratio R (vol% · cm ² / W) in an initial stage of the film formation is 1.5 (vol% · cm ² / W) or more. The step of forming the ITO film includes
(I) depositing a first ITO layer; and thereafter
(Ii) depositing a second ITO layer on top of the first ITO layer;
The manufacturing method as described in any one of Claims 1 thru | or 3 which has these. The first and second ITO layers are formed by sputtering,
In the step (i), as compared with the step (ii), the ratio R (vol% · cm ² / W) of the oxygen partial pressure P _O2 (vol%) to the plasma power density P _d (W / cm ² ). ) (R = P _O2 / P _d ) is large. The manufacturing method according to claim 7, wherein in the step (i), the ratio R (vol% · cm ² / W) is 1.5 (vol% · cm ² / W) or more. The manufacturing method according to claim 1, wherein the ITO film has a resistivity of less than 2.38 × 10 ⁻⁴ Ωcm. Before the step of forming the ITO film,
The manufacturing method according to claim 1, further comprising: forming a coating layer containing a metal oxide and / or a metal oxynitride on the glass substrate or the scattering layer. A translucent substrate having a glass substrate and an ITO film formed on the glass substrate,
The glass substrate includes at least one element selected from the group consisting of Bi (bismuth), Ti (titanium), and Sn (tin),
The translucent substrate characterized in that the ITO film is in a state of higher oxidation on the side closer to the glass substrate than on the side far from the glass substrate. A translucent substrate having a glass substrate, a scattering layer formed on the glass substrate, and an ITO film formed on the scattering layer;
The scattering layer includes at least one element selected from the group consisting of Bi (bismuth), Ti (titanium), and Sn (tin),
The translucent substrate, wherein the ITO film is in a state of higher oxidation on the side closer to the scattering layer than on the side far from the scattering layer.   The translucent substrate according to claim 11 or 12, wherein the ITO film has a degree of oxidation continuously or discontinuously decreased from a side closer to the glass substrate toward a side farther from the glass substrate.   The translucent substrate according to claim 11, wherein the ITO film has a thickness of 2 nm to 500 nm. The ITO film is composed of at least two layers, and has a first ITO layer on the side close to the glass substrate and a second ITO layer on the side far from the glass substrate,
The translucent substrate according to any one of claims 11 to 14, wherein the first ITO layer has a higher degree of oxidation than the second ITO layer. The translucent substrate according to claim 11, wherein the ITO film has a resistivity of less than 2.38 × 10 ⁻⁴ Ωcm.   The translucent substrate according to any one of claims 11 to 16, wherein the ITO film has an extinction coefficient of 0.0086 or less.   Furthermore, it has a coating layer containing a metal oxide and / or a metal oxynitride between the glass substrate and the ITO film, or between the scattering and the ITO film. The translucent substrate as described in 1. An organic LED element having a glass substrate, a first electrode layer, an organic light emitting layer, and a second electrode layer in this order,
An organic LED element provided with the translucent board | substrate as described in any one of Claims 11 thru | or 18.

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