JP2876988B2 - Electric heating glass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention provides a surface heating element on a glass surface to prevent dew condensation, melting of attached ice and snow, defrosting and antifogging, etc. The present invention relates to an electric heating glass.

[0002]

2. Description of the Related Art Conventionally, there have been many types of electrothermal glass in which a transparent conductive film as a surface heating element is formed on a glass surface in order to prevent dew condensation and to melt attached ice and snow.

FIG. 7 shows an example of such a prior art. That is, the outer glass 50 and the inner glass 52 are made of a laminated intermediate film 51 made of polyvinyl butyral or the like.
In the laminated glass joined by the following, at the peripheral edge of the boundary surface between the outer glass 50 and the laminated intermediate film 51,
A colored coating layer 54 is formed for concealment, and a transparent conductive film 53 as a surface heating element is formed on the boundary.

On the other hand, a bus bar 55 for power supply is laminated on the colored coating layer 54, and electricity is supplied to the transparent conductive film 53 through the bus bar 55 to heat the glass surface.

[0005] However, as shown in FIG.
5 is extended so as to protrude partially from the colored coating layer 54 (extended portion 56), so that most of the coating film breakage that occurs at the time of energization occurs at the boundary between the bus bar print 55 and the transparent conductive film 53. Met.

In such a boundary, the above-mentioned boundary may be improved. For this reason, most of measures against film breakage relate to a bus bar. For example, a method in which the edge is tapered (see Japanese Utility Model Application Laid-Open No. 62-457). Japanese Patent Application Laid-Open No. 62-99191, a two-stage bus bar at the boundary (Japanese Utility Model Application Laid-Open No. 62-456), and a protective print (Japanese Utility Model Application Laid-Open No. 62-99191) are known.

[0007]

Conventionally, as shown in FIG. 7, the bus bar 55 partially protrudes from the colored coating layer 54. Further, the state of attachment of these two is not always sufficient. Therefore, in response to this, a considerable potential difference is generated between the two, and in many cases, the membrane is broken in a form induced by the potential difference.

Accordingly, the bus bar 55, the transparent conductive film 5
(3) The prior art described above was invented to improve the boundary between the two. That is, these prior arts make progress in improving the boundary between the bus bar 55 and the transparent conductive film 53 and preventing the film from being cut between the two.

[0009] On the other hand, the fact that the bus bar partially protrudes from the colored coating layer means that the color of the bus bar is clearly visible from the outside of the vehicle, which may violate domestic security standards. Based on these social situations,
A need has arisen to completely hide the busbar over the colored coating.

However, the prior art (including the above-mentioned prior art with improvement) does not consider the case where all the bus bars are on the colored coating layer, and it can be said that the performance of the electrothermal glass is insufficient. That is, as shown in the comparative example (FIG. 10), in the case of the electrothermal glass, when all the bus bars are on the colored coating layer, the energization after leaving at high temperature (80 ° C., 28 days) results in the colored coating layer and the transparent conductive coating. , In particular, in the vicinity of the end of the colored coating layer near the center of the glass plate, resulting in the breakage of the transparent conductive film.

According to the present inventors' investigation into the cause, pigment particles of about 1 μm exist on the colored coating layer after firing, whereas the thickness of the transparent conductive film is as thin as 0.1 μm.
It was clarified that the film was cut off at the boundary between the two, and that the unevenness due to the pigment particles was particularly remarkable at the end of the colored coating layer closer to the center of the glass plate.

As the colored coating layer, a ceramic color print or a colored layer formed by printing an organic paint is used. The ceramic color print is composed of glass frit, pigment, and other additives. Since the glass frit is melted, the adhesive strength with the glass is increased and the glass frit can be baked.

At this time, the glass frit melts and becomes smooth by firing, so there is no problem. However, the larger the particle size of the components other than the glass frit and the insufficient firing, the more the glass frit is colored on the ceramic color print, that is, colored. Irregularities on the surface of the coating layer become remarkable, which causes problems such as generation of current-carrying distortion in the colored coating layer and an increase in inter-terminal resistance due to the bonding step of the laminated glass. This causes film breakage at the boundary between the colored coating layer and the transparent conductive film as described above.

Accordingly, a first object of the present invention is to cover the unevenness due to the pigment component of the colored coating layer when the bus bar is on the colored coating layer, and to prevent film breakage.
Further, it is another object of the present invention to provide an electrothermal glass which is not limited only to the film breakage, improves the durability of energization, and has good performance and appearance.

[0015]

In order to achieve the above object, the present invention is configured as follows. That is, in the present invention, a transparent conductive film (13) is formed on the surface of the laminated glass obtained by joining two glass plates through the intermediate film, on the surface of the laminated glass that is bonded to the intermediate film. Bus bar (15)
Energizing the coating-through, in electric glass heating the glass, the one glass plate of the above colored coating layer of the ceramic color print to the peripheral portion of the surface in contact with the intermediate film (14) is formed, The bus bar (15) is formed without protruding onto the colored coating layer (14), and a protective layer (16) is formed so as to cover the end of the colored coating layer (14) closer to the center of the glass plate. And a transparent conductive film (13) formed thereon.

The present invention is characterized in that a specific protective layer 16, that is, a protective layer 16 that provides a substantially smooth surface, is formed so as to cover the end of the colored coating layer 14 closer to the center of the glass plate. And The protective layer fills irregularities based on the pigment component and the like on the surface of the colored coating layer, and solves the conventional difficulties.

At the end of the colored coating layer after firing, components other than the glass frit, for example, pigment particles, are hardly covered by the layer formed by welding the glass frit contained in the colored coating layer. There is a tendency to be exposed, and it is considered that unevenness is generated on the end surface. In the portion other than the end portion of the colored coating layer, most of the particles of the components other than the glass frit are covered by the layer formed by welding the glass frit contained in the colored coating layer, and It is considered that the difficulty due to the irregularities is less likely to occur than at the end of the layer.

Therefore, it is the edge of the colored coating layer that is most likely to break the transparent conductive film. In the present invention, the protective layer which fills the unevenness of the edge and provides a substantially smooth surface. 16 is formed.

The protective layer 16 is transparent conductive film 13 has only to fill the unevenness of the end of the colored coating layer to provide a smooth surface to "real qualitative" so as not to broken membrane. Due to such a protective layer 16, the unevenness of the colored coating layer 14 is changed from an acute angle to a more rounded shape, the number of the protrusions is reduced, and the depth of the unevenness is reduced. Is preferred.

[0020] because "real qualitative" in smooth surface, a transparent conductive coating 13 is a means that the surface of the degree that does not cause deterioration of such film breakage, the shape of the convex portion, the number of protrusions, Since it is comprehensively determined in consideration of various factors such as the depth of the unevenness and the density of the unevenness, it is not always easy to define the numerical value. Taking the maximum height of unevenness as an example, the following is obtained. Assuming that the transparent conductive film 13 is formed to have a thickness of X (μm), the maximum height (R _max ) of the surface provided by the protective layer 16 (here, “maximum height”)
Means the maximum height (R _max ) defined in JIS B0601-1982) is 9 × X (μm) or less,
It is preferably 5 × X (μm) or less, particularly preferably X (μm).
m)

When the protective layer 16 fills the irregularities of the colored coating layer 14 and has a certain thickness or more, the smoothness of the surface becomes constant irrespective of the thickness. On the other hand, if the thickness of the protective layer 16 is too large, the appearance may be conspicuous. Therefore, the thickness of the protective layer 16 is preferably 5 μm or less.

For example, in the case where pigment particles having a particle size of about 1 μm are scattered in the colored coating layer 14 and a transparent conductive film is formed thereon with a thickness of about 0.1 μm, It is preferable that the maximum height of the surface by the protective layer 16 formed to cover the end of the layer 14 is about 0.1 μm or less.

In the protective layer 16 according to the present invention, which provides a substantially smooth surface, the protective layer 16 is made to be inconspicuous in appearance.
The protective layer is preferably made of a transparent substance having a refractive index of 2.0 or less. By setting the refractive index to 2.0 or less, particularly preferably in the range of 1.4 to 1.6 and approaching the refractive index of glass as the substrate, the occurrence of interference by the protective layer is suppressed, and the appearance becomes inconspicuous, preferable.

As such a substance having a refractive index of 2.0 or less,
For example, SnO ₂ (refractive index n = 2.0), SiO ₂
(N = 1.5), ZrO ₂ (n = 2.0), In ₂ O ₃
A simple substance or a mixture of metal oxides such as SnO ₂ (n = 1.9), TiO ₂ (n = 2.3), Ta ₂ O
₅ A composite oxide or the like having a high refractive index oxide such as (n = 2.1) and the above low refractive index oxide at an appropriate ratio.

As a method of forming the protective layer 16 in the present invention, there are the following four methods. First, a method in which a glass frit is mixed with a thickener, applied by printing or the like, and baked and baked; second, acetylacetonate, alkoxide, or the like of a metal of a metal oxide to be formed as the protective layer 16 organic metal salts, halides, acetates, metal salts such as nitrate salts <br/> or chelate compound, alcohol,
Aromatics such as benzene, or a solution in a solvent such as chlorinated solvents (hereinafter, referred to as a metal salt solution) After applying the method of thermal decomposition to form a metal oxide, the third, gold <br A solution obtained by dissolving a metal alkoxide in water for hydrolyzing the metal alkoxide and a mixed solution of the metal alkoxide and an alkoxide as a solvent compatible with water (hereinafter referred to as a metal alkoxide solution) is applied. And heating and firing to form a metal oxide film by a sol-gel method. Fourth, a sol in which fine particles of a metal oxide are dispersed as colloidal particles in water or an organic solvent (hereinafter referred to as a metal oxide sol) Is applied, heated and dried to form a metal oxide film by a sol-gel method.

The glass frit used in the first method includes a ceramic color print 14 and a bus bar 15.
The melting point of the glass frit may be the same as that of the glass frit contained therein.
0 to 640 ° C.) or lower. Because
This is because the glass frit needs to have a melting point equal to or lower than the firing temperature in order to make the surface sufficiently smooth by firing.

The glass frit is preferably printed by a screen printing method in the same manner as the ceramic color print and the bus bar print in the process, and is preferably printed at a time of firing. The glass frit is mixed with a thickener or the like to have a viscosity suitable for screen printing, for example, 1000.
It is preferable to adjust to about 20,000 cP (centipoise) and perform screen printing.

Since the layer formed by welding glass frit is mainly composed of silicon oxide, it is transparent and has a refractive index of about 1.5, which is preferable as the protective layer of the present invention.

In the above-mentioned second to fourth three methods, a method of applying a metal salt solution, a metal alkoxide solution, a metal oxide sol or the like (including a substance which can be converted into a metal oxide by firing) is used as a screen. Printing method, spray method, roll coater method, meniscus coater method, printing method,
A brush coating method or the like is possible.

Among the above-mentioned methods using the second to fourth liquids, the third method of firing and forming a liquid containing a metal alkoxide can be applied by a simple screen printing method in a manufacturing process, so that the efficiency is high. It is preferred. In this case, in order to obtain the desired metal oxide, suitably, the metal alkoxide may be made tone. Then, a liquid containing the desired metal alkoxide and having a viscosity suitable for screen printing with a thickener, for example, a viscosity adjusted to about 1000 to 20,000 cP is screen-printed and fired to form the protective layer 16 of the present invention. It is desirable.

Further, by arranging one end of the protective layer 16 in a gradation print of a ceramic color print, the appearance of the protective layer 16 can be made more inconspicuous and effective.

The details will be described in the accompanying drawings and in the embodiments.

[0033]

According to the structure described above, the protective layer 16
Vignetting image sticking by sintering, the ceramic color print 14 and the glass border, the ceramic color print 14 surface, the bus bar 15 and the boundary of the ceramic color print 14, and including a portion of the bus bar, the transparent conductive film 1
The portion serving as the base of No. 3 is smoothed to reduce unevenness.

Therefore, the ceramic color print 1
Even if the transparent conductive film 13 having a thickness much smaller than the thickness of the transparent conductive film 4 is applied, there is no local increase in resistance, and the film can be prevented from being cut.

[0035]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partially enlarged longitudinal sectional view of an electric heating glass according to one embodiment of the present invention.

First, the electrothermal glass forms a laminated glass in which the outer glass 10 and the inner glass 12 are joined by a laminated intermediate film 11 made of polyvinyl butyral or the like.

One of the glass bonding surfaces of the laminated glass (FIG. 1)
, A transparent conductive film 13 as a surface heating element is formed on the glass bonding surface of the outer glass sheet 10, and the ceramic color print 1 plays a role of hiding and the like.
A bus bar 15 for power supply is mounted and laminated on the base 4 without protruding from the bus bar, and a current is applied to the transparent conductive film 13 via the bus bar to heat the glass surface.

Furthermore, the boundary insertion of the protective layer, which is the most important feature of the present invention, is as follows.
The ceramic color print 1 which covers the end near the center of the glass plate of
4 and bus bar 15 and ceramic color print 14
, And further cover a part of the bus bar 15 which is the base of the transparent conductive film 13 to smooth its surface and prevent a local resistance increase which may cause the film to break.
Improve the energization durability. For easy understanding, FIG. 2 is a plan view of the outer plate, and FIG.
A section is shown.

As shown in FIG. 3, it is also preferable to form a taper in the ceramic color print near the print edge 19 of the ceramic color print 14 and form the protective layer 16 thereon.

The edge of the surface of the protective layer 16 which is in contact with the transparent conductive film and which is closer to the center of the glass is also tapered to reduce the level difference, which is more effective in preventing the transparent conductive film from breaking.

The bus bar 15 used in the present invention is preferably a silver paste containing silver and glass frit or the like, and any other suitable bus bar can be used as long as it can sufficiently exert the effects of the present invention. .

On the other hand, the ceramic color print 14 is made of glass frit, CuO—Cr ₂ O ₃ , TiO ₂ , Fe ₂
An appropriate method such as mixing a pigment such as O ₃ , CoO, or Cr ₂ O ₃ and a filler such as alumina, and printing out an ink is used.

As a method of manufacturing the protective layer, it is most efficient and preferable in the manufacturing process that the protective layer is applied by a screen printing method in the same manner as a ceramic color print or a bus bar print, and is baked at the time of firing.

[0044] Further, as the printing thickness of the protective layer, as described above, it may be a thickness such that the actual qualitative smooth surface with a protective layer, is not limited. For example, in consideration of the fact that the pigment, which is a component of a ceramic color print, usually has a particle size of 5 to 15 μm and that pigment particles of about 1 μm exist even after firing, the film thickness after firing is about 0.1 μm. 1-5 μm range, especially 1 μm
It can be said that it is good to set it to about m. Also, 5μ
When the thickness is larger than m, the edge of the protective layer is conspicuous, which is not preferable in appearance. If the thickness is less than 0.1 μm, a substantially smooth surface may not be provided.
It is preferably at least μm.

A ceramic color print is necessary because it is important in terms of concealing properties and appearance when bus bars are stacked, but it is necessary to smooth the print surface in order to improve the current-carrying performance. In view of the above, it can be said that the print thickness of the above-mentioned protective layer is optimal.

For various reasons described above, the print width of the protective layer should be 1 to 3 mm from the in-plane bus bar edge 18 to the glass edge 17 and 1 to 3 mm from the in-plane ceramic color print edge 19 to the in-plane direction. A good distance is desirable.

The transparent conductive film is not particularly limited, but may include SnO ₂ ,
A multilayer film having a configuration sandwiching a metal oxide such as ITO, ZnO, TiO ₂ , an ITO film, a SnO ₂ : F film, a SnO film;
₂ : a single-layer film such as an Sb film or a ZnO: Al film is generally used, and the sheet resistance is desirably 10 Ω or less. The film thickness may be, for example, an external color tone or a spectral value (T _V , T _E). , R
_V , R _E ), and may be adjusted according to the purpose (the total thickness is often 500 to 1000 °).

The transparent conductive film 13 is applied to one of the glass bonding surfaces, but the laminated intermediate film 11 on the inner side of the outer glass 10 is used so that ice, snow, etc. attached to the outer surface of the outer glass 10 can be easily melted. It is better to be provided on the side. As a forming method, an appropriate method such as a vacuum evaporation method or a sputtering method can be used.

In addition to the above, by providing one end (print edge) of the protective layer in a gradation print of a ceramic color print, a good electrothermal glass can be provided without the protective layer being noticeable in appearance. can do. An example is shown in FIG. 5, and a cross-sectional view taken along the line CC ′ is shown in FIG. 14 wear <br/> color coating layer of the ceramic color print, 24 is a gradation print of such colored coating layer.

FIG. 5 shows an example in which the gradation print 24 is formed in a dot shape, but other shapes may be used. As a whole, the ceramic color print edge 19
What is necessary is just to be formed so that it might look like it was blurred in the in-plane direction from.

The protective layer 16 of the present invention covers the printed edge 19 of the colored coating layer and prevents the transparent conductive film 13 from breaking. Since the portion of the transparent conductive film 13 that is directly coated on the glass plate around the gradation print 24 has sufficient conductivity, the film is hardly cut off at the edge of the gradation print 24.
Since the print edge 20 of the protective layer 16 is in the gradation print 24, the protective layer is not noticeable in appearance.

Since the present invention is configured as described above, it is possible to completely prevent breakage of the film which has conventionally occurred.

Example 1 A ceramic color print was screen-printed around the outer glass 50 as shown in FIG. 2 and pre-dried, and then an Ag paste for a bus bar was screen-printed as shown in FIG. 2 and pre-dried. Further, as shown in FIG. 4, a glass frit was mixed with a thickener, screen-printed, dried, baked at 630 ° C., and then overlapped with the inner glass sheet and bent.

The thickness of the ceramic color print after firing was 15 μm, the thickness of the bus bar was 20 μm, the thickness of the protective layer formed by welding glass frit was about 1 μm, and the surface of the protective layer had a _{Rmax of} 0.1 μm or less. Was. Next, Z
A transparent conductive film (total thickness: about 0.1 μm) having a composition of nO / Ag / ZnO was formed, and joined to the inner glass and the intermediate film as shown in FIG. 4 to form a laminated glass. The inter-terminal resistance between the bus bars of the laminated glass was 9.53Ω.

The resistance after holding the laminated glass at 80 ° C. for 30 days was 9.26 Ω, and no breakage of the film was observed even when current was supplied. No current distortion occurred.

Example 2 Instead of the glass frit, the protective layer of Example 1 was screen-printed with a sol-gel reaction solution containing a small amount of water obtained by diluting silicon alkoxide with alcohol, and then simultaneously printing the ceramic color print and the bus bar. It was formed by baking.

The thickness of the protective layer after firing was 0.5 μm, and the surface had an R _max of about 0.2 μm. All other steps were the same as in Example 1 to form a laminated glass.
The resistance between terminals is 11.31Ω, 80 ° C., and after 30 days, 11.3Ω.
The resistance was 54Ω, and no breakage of the film was observed even when the current was applied.
No current distortion occurred.

Comparative Example A laminated glass as shown in FIG. 10 was formed in the same manner as in Example 1 except that no protective layer was formed. The initial terminal-to-terminal resistance was 9.53Ω, but was 80%.
The resistance after standing at 30 ° C. for 30 days was 11.63Ω, and the film was cut off when electricity was supplied.

[0059]

According to the present invention, the following effects can be obtained from the above configuration.

That is, by covering the ceramic color print and the bus bar, which are the bases of the transparent conductive film, with a specific protective layer, the film of the transparent conductive film is particularly remarkably cut, and the portion closer to the center of the glass plate of the ceramic color print is obtained. By covering the end portions, it is possible to prevent the film from being cut or to increase the sheet resistance of the transparent conductive film in this portion, and it is possible to suppress the occurrence of conduction distortion.

Therefore, even if a transparent conductive film that is much thinner than the thickness of the ceramic color print is applied, there is no local increase in resistance and the film can be prevented from being cut.

Further, by printing the protective layer 16 also on the boundary between the bus bar 15 and the ceramic color print 14, the prevention of film breakage and the improvement of the current-carrying durability become more effective.

In addition, since the print edge of the protective layer 16 away from the bus bar is set in the gradation print of the ceramic color print 14, it is possible to provide an electrically heated glass having a good appearance.

Further, by setting the refractive index of the protective layer to 2.0 or less, preferably in the range of 1.4 to 1.6 and approaching the refractive index of glass as a substrate, the occurrence of interference is reduced and the appearance is good. To provide excellent electrothermal glass.

[Brief description of the drawings]

FIG. 1 is a partially enlarged longitudinal sectional view of an electric heating glass for an automobile according to an embodiment of the present invention.

FIG. 2 is a plan view of an outer glass sheet.

FIG. 3 is a sectional view taken along AA ′ of FIG. 2;

FIG. 4 is a partial cross-sectional view of the electrothermal glass of the present invention formed in Examples 1 and 2.

FIG. 5 is a partial plan view of the electrothermal glass according to the present invention when a gradation print of a colored coating layer is formed.

FIG. 6 is a sectional view taken along CC ′ in FIG. 5;

FIG. 7 is a partially enlarged longitudinal sectional view of a conventional example when a bus bar partially protrudes from a colored coating layer.

FIG. 8 is a plan view of the outer glass plate when the bus bars are stacked without protruding on the ceramic color print.

FIG. 9 is a sectional view taken along the line BB ′ of FIG. 8;

FIG. 10 is a partial cross-sectional view of an electrothermal glass formed in a comparative example.

[Explanation of symbols]

 10, 50: outer plate glass 11, 51: laminated intermediate film 12, 52: inner plate glass 13, 53: transparent conductive film 14, 54: colored coating layer 15, 55: bus bar 56: bus bar extension 16: protective layer 17 : Glass edge 18: Busbar edge 19: Print edge of colored coating layer 20: Edge closer to glass center 24: Gradation print

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05B 3/02-3/82

Claims (6)

(57) [Claims] 1. A transparent conductive film (13) is formed on a bonding surface of one laminated glass plate and an intermediate film of a laminated glass obtained by joining two glass plates via an intermediate film, and a power supply bus bar is provided. (15) to energize the coating film through, in electric glass heating the glass, one glass plate of the above wearing <br/> color coating of the ceramic color print to the peripheral portion of the surface in contact with the intermediate layer A layer (14) is formed, and the bus bar (15) is formed without protruding onto the colored coating layer (14);
A protective layer (16) is formed so as to cover an end of the colored coating layer (14) closer to the center of the glass plate, and a transparent conductive film (13) is formed thereon. Electric heating glass. 2. A protective layer (16) is electrically heated glass according to claim 1 Symbol mounting, characterized in that a metal oxide film formed by baking a liquid containing a substance that can be a metal oxide by calcination . 3. A protective layer (16), according to claim 1 or 2, wherein the glass frit is a layer formed by welding
Electrothermal glass as described. 4. The method according to claim 1, wherein the transparent conductive film (13) is a colored coating layer (1).
4. The electrothermal glass according to claim 1 , wherein a protective layer (16) is formed so as to cover the colored coating layer (14) in a region overlapping with (4). 5. 5. A method according to claim 1, wherein the transparent conductive film is a colored coating layer.
4) and a protective layer so as to cover the colored coating layer (14) and the bus bar (15) except for a portion where the bus bar (15) and the transparent conductive film (13) are in contact with each other in a region overlapping with the bus bar (15). The electrothermal glass according to claim 1 , 2, 3, or 4, wherein (16) is formed. 6. The method of claim 1, characterized in that within the gradient print protective layer one end is an incoming color coating layer (16) (14), 2, 3, 4 or 5, wherein the heating glass.