JPH03232745A - Electrically conductive glass and production thereof - Google Patents

Abstract

PURPOSE:To prevent an alkali from diffusing by laminating an alkali barrier film consisting essentially of oxides of one or more selected from Zr, Hf, Nb, Sn and La and Si and electrically conductive film on the surface of alkali- containing glass. CONSTITUTION:Alkali-containing glass plate such as soda-lime silica glass is washed and dried. The resultant glass plate is subsequently arranged in a sputtering device, evacuated and then subjected to DC sputtering in a mixed gas of Ar and O2 using one or more metals selected from Zr, Hf, Nb, Sn, La, Ti, Ta, MO, W and Cr and Si as a target to form an alkali barrier film of a silicon compound, consisting essentially of oxides containing one or metals such as Zr and Ti and Si at an atomic ratio of the total amount of the one or more metals to the Si within the range of (95/5)-(4/96) and having >=50Angstrom film thickness. An electrically conductive film such as ITO film (indium oxide film containing Sn) is then laminated thereon by DC sputtering to afford electrically conductive glass.

Description

DETAILED DESCRIPTION OF THE INVENTION [Prior Art] The present invention relates to a conductive glass with an alkali barrier film that prevents alkali ions from diffusing from a glass base of an alkali-containing glass.

Glass plates as transparent materials are chemically stable, have excellent surface hardness, can withstand high temperatures of about 500°C to 700°C, and have excellent electrical insulation and optical properties, so they are used for architectural and vehicle applications. It is used not only as a window glass material for aircraft, but also for optical parts, electrical parts, electronic parts, etc.

In particular, recently, conductive glass plates in which a conductive film is formed on the glass plate surface have been used for display elements such as liquid crystal elements, electrochromic elements, and electroluminescent elements, amorphous solar cell substrates, and the like.

As the glass substrate for these conductive glass plates, there is a tendency to use soda lime silica glass plates, which are the most widely used and inexpensive. Since it contains alkaline components such as sodium and potassium, it has the disadvantage that the performance of the coated conductive film deteriorates due to the diffusion of alkali ions from the glass base to the surface after long-term use. For example, the conductive film of the conductive glass plate becomes cloudy or its transparency decreases, the resistance value of the conductive film increases, or its chemical and physical durability decreases.

That is, in a liquid crystal display element, an oxidation-reduction reaction occurs on the surface of the display electrode due to the alkali diffused from the glass, altering the quality of the indium oxide film (ITO film) or tin oxide film (NESA film), which are the transparent electrode materials, and furthermore, The liquid crystal itself also deteriorates due to electrolysis. Electrochromic elements also wear out their electrodes for the same reason, causing a decrease in the durability of the electrochromic materials such as tungsten oxide and molybdenum oxide, and deteriorating the element. Furthermore, in the case of electroluminescent elements, alkali that comes out from the glass surface due to diffusion penetrates the conductive film and enters the phosphor material, changing the luminous efficiency and even the luminous color. Furthermore, in the case of amorphous solar cells, the resistance value of the conductive film increases, significantly reducing the photoelectric conversion efficiency, and sometimes the alkali that penetrates the electrode and comes out diffuses into the amorphous silicon, reducing the conversion efficiency. It is believed that there is a risk of a decline.

Alternatively, in alkali-containing glasses such as soda lime silica glass, alkali ions tend to move easily during high-temperature processing, and due to the diffusion of alkali ions during high-temperature processing during the manufacture of conductive glass or various coated glasses. There also arises a drawback that the performance of the conductive film or various coating films is deteriorated.

A typical solution to these drawbacks is to form a thin film on the surface of ordinary soda-lime silica glass to prevent some kind of alkali diffusion, and silica films are generally used. The reason why a silicon oxide film (for example, a SiO□ film) is used to prevent alkali diffusion is that the film is amorphous, and when another thin film, such as a conductive film, is formed on top of it, it is essentially the same film that is formed on glass. The refractive index of the silicon oxide film is slightly lower than that of glass, but it is close to that of glass, and it is transparent to a wider range of light than normal plate glass, so the transparency of glass is not impaired.

[Problems to be Solved by the Invention] However, while the conductive film formed on the alkali barrier film is formed by a direct current sputtering method that can form a uniform film over a large area at high speed, silicon oxide When attempting to form a film using a DC sputtering method using a Si target, the surface of the Si target is oxidized during sputtering and its conductivity decreases, making it impossible to maintain stable sputtering. For this reason, films have been formed by RF sputtering, CVD, or the like using an oxide target.

Therefore, apart from the method of forming the conductive film, the R of the silicon dioxide film is
It is not possible to form a silicon dioxide film continuously with a conductive film in-line because tuning of F sputtering and sputtering atmosphere control is required, or the film must be formed using a CVD method using a separate device. The problem was that productivity was low.

[Means for Solving the Problems] The present invention has been made based on the above-mentioned problems by discovering a new alkali barrier film that can be formed by direct current sputtering, and in which a new alkali barrier film is formed on the surface of an alkali-containing glass. A conductive glass in which an alkali barrier film for suppressing alkali diffusion and a conductive film are sequentially laminated, the alkali barrier film comprising Zr, Hf, Nb, Sn,
Zr, Hf, Nb, Zr, Hf, Nb,
Sn.

Provided is a method for producing conductive glass, characterized by forming an alkali barrier film mainly composed of an oxide containing a small amount of La and Si, and then forming a conductive film. .

The alkali barrier film of the present invention comprises Zr, )If, N
b.

This is a film whose main component is an alkali barrier film whose main component is an oxide containing Si and at least one of Sn and La. In addition, the alkali barrier film of the present invention may optionally contain T.
It may contain at least one of i, Ta, Mo, W, and Cr.

The composition of the alkali barrier film of the present invention includes Zr,
It is preferable that Si be contained at a ratio of 5 or more Si atoms to a total amount of 95 atoms of metals such as Hf. This is because if the Si content is below this percentage, the film becomes crystalline and the alkali barrier ability is significantly reduced. Further, it is preferable that Si be contained in a ratio of 96 or less Si atoms to a total of 4 atoms of metal such as Zr. If the Si content exceeds this ratio, the surface of the target will be oxidized, making it impossible to stably form a film using the DC sputtering method.

The refractive index of the alkali barrier film of the present invention can be freely adjusted depending on its composition. Table 1 shows the change in refractive index depending on the composition of the alkali barrier film when Zr is used as the metal.

Table 1 (All film thicknesses are 1,000 people) After immersion in water at 100℃ for 2 hours under 1l atmosphere
, (Visible light transmittance), and Rv (Visible light reflectance) were rated ○ if the rate of change with respect to before immersion was within 1%.

°2 If the amount of Na" eluted into pure water after contacting with pure water and storing at 90℃ for 24 hours is 0.8μg/cm" or more, mark it as "X", and if it is less than 0.8μg/cm", mark it as "○". did.

Therefore, in the case of a conductive glass used as a transparent electrode plate of a display element or the like on which a transparent electrode such as an ITO film (tin-containing indium oxide film) is formed as a conductive film, the composition of the alkali barrier film of the present invention If the refractive index of the transparent electrode is made to be the same as that of the transparent electrode, the refractive index of the part where the transparent electrode pattern is formed on the alkali barrier film and the part where only the alkali barrier film is formed without the transparent electrode is the same. Since no difference occurs, the transparent electrode pattern is not conspicuous, and the so-called "bone visible" phenomenon of the transparent electrode pattern can be prevented.

For example, in a conductive glass having a structure of glass plate/alkali barrier film made of an oxide containing Zr and Si/ITO film, Zr:Si=70 from Table 1 in accordance with the refractive index of 1.9 of the ITO film. It may be about 30. Or, in the manufacture of display elements, etc., in terms of alignment,
In cases where visibility of the transparent electrode pattern is preferred, it is appropriate to have a refractive index different from that of the ITO film, and a low refractive index can be achieved by increasing the proportion of Si. As described above, the composition of the alkali barrier film of the present invention can be appropriately selected depending on the refractive index of the conductive film formed thereon.

The thickness of the alkali barrier film of the present invention is preferably 50 Å or more so that sufficient alkali barrier performance is exhibited. Among these, a range of 100 to 5,000 people is the most practical.

Glasses that can be applied to the conductive glass of the present invention include not only the most widely used soda lime silica glass containing 10 to 20 wt% of Na and K, but also various other alkali-containing glasses.

In the conductive glass of the present invention, the conductive film formed on the above-mentioned alkali barrier film may be an ITO film, F or S.
Transparent conductive oxide films such as 5nOz films doped with b, etc., ZnO films doped with A1, etc., conductive metal films such as Ag, Au, etc., which may be deteriorated by alkali ions. It is good if it exists and is not particularly limited.

[Example] Example 1 Alkali component R of lOcmX lOcmX 3 mm,
An ordinary glass plate (soda-lime silica glass plate) containing 15% O (R: Na, K) was thoroughly washed with detergent, washed with water, and dried. After placing this glass plate in a vacuum chamber of a sputtering device and evacuating the chamber to I
=lO:90) by direct current sputtering in a mixed gas of argon and oxygen at 2 x 1O-3 Torr,
Zro, approximately 1000 people formed l5I0.902 films.

Comparative Example 1 1000 SiO□ films were formed on the same glass plate as in Example 1 by CVD using SiH4 and 0□ gas.

Example 1 product and Comparative Example 1 product were brought into contact with pure water and 9
After holding at 0°C for 24 hours, Na'″ dissolved in pure water.
The alkali barrier property was measured by measuring the amount of 0.60 μg/cm" for Example 1 product, and 0.60 μg/cm" for Comparative Example 1 product.
61 μg/cm". Also, Example 1 product and Comparative Example 1
Each product was washed with 5% NaOH, then brought into contact with pure water at room temperature for 24 hours, and the amount of Na'' eluted into the pure water (the amount of Na'' adsorbed during the above washing) was measured to determine the alkali adsorption property. When investigated, it was 0.13μg/cm for Example 1 product.
, it was 0.14 μg/cm 2 for one comparative example. From this, it was found that the Example 1 product had almost the same characteristics as the Comparative Example.

Example 2 In the same manner as in Example 1, lro, lSio, e02
Approximately 200 people formed a membrane.

Example 3 ZrSi2 target (Zr:SCI
:2), and in the same manner as in Example 1, Zro3s
Approximately 200 people formed sio, 6602 membranes.

Example 4 In the same manner as in Example 3, Zro, assio, as
Approximately 500 people formed Oz films.

Each of Examples 2 to 4 was brought into contact with pure water, and 8
After being stored at 5°C for 24 hours, the alkali barrier properties and alkali adsorption properties were measured and the results are shown in Table 2.

Table 2 For Examples 1 to 4, after each alkali barrier film was formed by direct current sputtering, an ITO film was continuously formed on the alkali barrier film by direct current sputtering, and then stored at 90°C for 24 hours. However, there was no change in the appearance of the ITO film.

Furthermore, even when Hf, Nb, Sn, and La were used in place of Zr, the same results as in the above example were obtained, and the alkali barrier performance was confirmed.

[Function] In the present invention, in a target made of metal such as Zr, Hf, etc. and Si, Zr, Ti, Ta, Hf, Mo,
W, Nb.

La, Cr, etc. are mostly silicon compounds, and Sn is 5
It exists as an L-Sn alloy and has less activity against oxygen than Si, so it does not oxidize. It is thought that it is possible to form a film.

[Effects of the Invention] Since the conductive glass alkali barrier film of the present invention can be formed by direct current sputtering, a uniform film can be stably formed and provided over a large area at high speed. This is a great advantage especially in terms of productivity, since the alkali barrier film and the conductive film can be successively formed in-line when the conductive film is formed on the alkali barrier film using the DC sputtering method. .

The conductive glass with an alkali barrier film of the present invention is particularly suitable as an alkali diffusion prevention film for conductive glasses used in display devices such as liquid crystal devices, electrochromic devices, electroluminescent devices, amorphous solar cell substrates, etc.
As can be seen from Table 1, it also has heat resistance, and is stable and does not deteriorate during the manufacturing process of display elements, solar cells, etc. and various environmental conditions thereafter. Of course, in addition to these, we also provide conductive coatings and heat ray reflection prevention on glass plates for automobiles, aviation, railway vehicles, transportation vehicles, construction, various devices, optical parts, electrical parts, and electronic parts. It can be usefully applied to base coats when forming coatings, reflective coatings, colored coatings, and coatings with the function of the lot number type.

Furthermore, when sealing the periphery of a liquid crystal cell, etc., if the alkali barrier film of the present invention is interposed between the sealant and the glass,
It is also possible to prevent peeling of the sealant due to alkali.

Further, the alkali barrier film of the present invention is made of metal such as Zr and Si.
Since a desired refractive index can be obtained by changing the ratio of , it can be used in a wide variety of applications.

Furthermore, since the alkali barrier film of the present invention has low alkali adsorption, it can be used satisfactorily in the production of liquid crystal cells and the like even if there is a step of washing with an alkali-containing liquid.

Claims (5)

[Claims] (1) A conductive glass in which an alkali barrier film for suppressing alkali diffusion from the glass and a conductive film are sequentially laminated on the surface of the alkali-containing glass, the alkali barrier film being Zr, Hf, Nb, Sn, A conductive glass characterized in that it is a film whose main component is an oxide containing at least one kind of La and Si. (2) The alkali barrier film is Ti, Ta, Mo, W,
The conductive glass according to claim 1, characterized in that it contains at least one kind of Cr. (3) The alkali barrier film is Zr, Hf, Nb, Sn
, La, Ti, Ta, Mo, W, Cr total amount 9
5 atoms or more of Si, and the total amount of the above metals is 4
The above metals and Si at a ratio of 96 atoms or less to Si atoms
The conductive glass according to claim 1 or 2, characterized in that the main component is an oxide containing. (4) Zr, Hf, Nb on the surface of alkali-containing glass
, Sn, and La, and an alkali barrier film whose main component is an oxide containing Si, and then a conductive film is formed. (5) The method for manufacturing conductive glass according to claim 4, characterized in that the conductive film is formed continuously with the alkali barrier film by a DC sputtering method.