JPH0963758A - Electric heating glass - Google Patents

Abstract

(57) [Abstract] [Problem] Even if a part of the bus bar breaks at any place,
Provide electrically heated glass with excellent safety that does not cause sparks or electric shock. SOLUTION: An upper side bus bar 1 is composed of a plurality of bus bar elements 1M and 1S each having one open end near both sides of one side of a transparent conductive film 3, and the bus bar element 1 is provided.
M and 1S are electrically heated glass which have parallel portions which are adjacent to each other with a space therebetween and which are in contact with the transparent conductive film 3 at the parallel portions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrically heated glass which is useful as, for example, window glass for vehicles, glass for building materials and the like.

[0002]

2. Description of the Related Art Conventionally, in severe winters and cold regions,
There are problems such as snow accumulation, icing, frosting, or clouding on the windshield or rear glass of vehicles such as trains, trains, trucks, passenger cars, etc., or on the window glass of buildings, which obstructs visibility. It is difficult to quickly remove water and the like.

On the other hand, it has been proposed to use electrically heated glass for the window glass. These conventional electrically heated glass, for example, if it is a window glass of an automobile, generally two plate glass of substantially trapezoidal shape corresponding to the window frame, and a resin film sandwiched between the two plate glass, A pair of bus bars (current-carrying electrodes) provided between the two glass sheets above and below or around the periphery of the window glass.
And a transparent electrothermal film (transparent conductive film) provided so as to be connected to these bus bars.

As a transparent electrothermal film, for example, ITO
(Compound oxide of indium and tin), thin film gold or silver, etc. are used, and the transparent electric heating film is energized from the battery via the bus bar to heat the window glass etc., and this heat causes snow melting, ice melting. , Anti-fog etc. will be done quickly.

In recent years, various transparent electrothermal films used for electrically heated glass have been developed, and the glass can be heated more quickly, for example, by applying a high voltage of 280 V or more for heating. Suitable gallium-containing zinc oxide films and the like are known.

In these electrically heated glass, when the glass is broken or cracked, or in the case of a collision accident, etc.
If the power is continued in the destroyed state, there is a danger of a dangerous state such as electric shock, abnormal heat generation, ignition, and smoke generation depending on the cracking method. For this reason, various measures have been taken in the method of supplying power to the bus bar, and a crack detector for detecting glass breakage has been provided to avoid danger.

FIG. 6 shows a basic shape of a conventional bus bar. As shown in FIG. 6, power is supplied to the pair of bus bars 1 and 2 from one side of the bus bar on the lower left side of the glass (hereinafter, referred to as one side power supply method). FIG. 8 is also a diagram showing an example of a conventional one-sided power feeding method.

In this one-sided power supply system, when the resistance of the bus bar is high, loss due to heat generation in the bus bar occurs,
The power applied to the transparent heating film becomes small, resulting in power loss. In the single-sided power supply system, if the bus bar breaks due to an accident or the like, depending on the cracking method, sparks or abnormal heat may be generated at the broken part, and the intermediate resin film may be ignited, which may be dangerous. That is, the one-sided power supply method has a drawback that sparks, ignition, smoke, or the like may be caused depending on the magnitude of the current value flowing in the bus bar or how the current bar flows.

On the other hand, as shown in FIG. 7, a double-sided power supply system has been proposed in which terminals are provided at the left and right ends of each of the upper side bus bar 1 and the lower side bus bar 2 so that power is supplied from the left and right ends of the bus bar respectively. There is. According to this method, even if a part of the bus bar is broken on the left and right bus bars and the upper part of the glass, a potential difference does not occur at the broken part of the bus bar, and ignition due to spark or abnormal heating can be suppressed. .

Further, in Japanese Patent Laid-Open No. 4-46847,
Using this double-sided feeding method, the crack detector of the method of detecting the breakage of the glass by detecting the current value flowing in the left and right busbars located near the left and right sides of the glass of the busbar 1 on the upper side of the glass Is also proposed.

[0011]

However, in the crack detection method in the double-sided power supply method, cracks can be detected when the bus bar breaks on the left and right side portions of the glass, but the upper side bus bar 1 is a transparent electric heater on the upper side. When the bus bar was ruptured at the portion in contact with the film, the change in current was too small and detection was difficult in terms of accuracy. Especially, as mentioned above, 280V
When the above-described high voltage is applied to heat by energization, the flowing current is usually small, so that the change in current when the glass is broken is extremely small and detection is difficult.

It is an object of the present invention that, even if a crack occurs in a window glass for a vehicle or a building material glass and a part of a bus bar breaks at any place, no spark or electric shock is generated and the safety is excellent. It is to provide an electrically heated glass.

[0013]

DISCLOSURE OF THE INVENTION According to the present invention, a pair of bus bars, each of which includes an upper side bus bar and a lower side bus bar provided on each of the upper and lower sides of a sheet glass, and the sheet glass are connected to each other. In an electrically heated glass composed of a transparent conductive film provided on the surface of, the upper side bus bar is composed of a plurality of upper side bus bar elements, and the plurality of upper side bus bar elements are the upper side of the transparent conductive film at the upper side of the plate glass. Has an open end in the vicinity of both sides and extends to the power feeding portion, and at the connecting portion of the upper side bus bar with the transparent conductive film, the plurality of upper side bus bar elements are adjacent to and face each other. A plurality of upper side bus bar elements are in contact with the transparent conductive film at the parallel portions. Providing electric heated glass.

That is, the shape of the upper side busbars of a pair of busbars respectively connected to the upper and lower opposite sides of the transparent conductive film forming the electrically heated glass, particularly the connection between the busbars and the transparent conductive film. The above problem can be solved if the shape of the portion is configured to satisfy the following requirements.

1) A plurality of upper side busbar elements each having an open end near both sides of one side of the transparent conductive film connected, and the parallel portions in a state where these busbars face each other without contacting each other. Have. 2) The plurality of upper side busbar elements of the above 1) are both in contact with the upper side of the transparent conductive film in the parallel portion (hereinafter simply referred to as the busbar parallel portion).

In the present invention, the upper side of the paper is called the "upper side" for convenience. Depending on the form in which the electrically heated glass of the present invention is incorporated and used, the “upper side” may be located on the left side, the right side, or the lower side.

The plurality of upper side bus bar elements are
It is preferable to have a structure in which one power feeding unit is connected to one, because the structure of the power feeding unit can be simplified. The plurality of bus bar elements are used in a plurality of two or more, but it is preferable to use two in practice.

In the present invention, the power feeding section means a portion on the bus bar where electricity is supplied to the bus bar via the power feeding terminal. Therefore, when the power supply terminal is provided on the bus bar, the power supply unit is aligned with the position of the power supply terminal. Also,
In the present invention, the open end means the end of the bus bar element other than the power feeding portion.

[0019]

According to the electrically heated glass of the present invention having the above-mentioned structure, even if a break occurs at any position of the bus bar,
That is, even if the glass is ruptured from any of the upper, lower, left, and right sides, a potential difference does not occur as in the above-described double-sided power supply method, and therefore sparks, abnormal heat generation, ignition, etc. at the ruptured portion do not occur.

Furthermore, in the electrically heated glass of the present invention, since the potential difference between the two busbar elements in the busbar parallel portion is small, the current flowing between them is small. In fact, the current flowing in the busbar element outside the glass of the two busbar elements in the parallel part is
It is smaller than the current flowing through the inner bus bar elements arranged in parallel with this.

Therefore, when the inner busbar element breaks, the current decrease ratio of the inner busbar element and the current increase ratio of the outer busbar element are larger than those of the conventional double-sided power supply busbar, and the breakage detection performance by the current value monitor is high. Be more sensitive and improve safety.

In the electrically heated glass of the present invention, if another crack detecting means capable of electrically detecting the occurrence of cracks in the glass plate is provided, the safety is further improved.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following preferred embodiments. Examples of the plate glass used in the present invention include ordinary glass, tempered plate glass, and partially tempered plate glass. These may be colored to the extent that transparency is not impaired. Further, the shape of these plate glasses is not limited to a flat plate shape such as glass for building materials, and may be a curved surface processed into various shapes and curvatures, for example, used for windshields of various vehicles. It may have a substantially trapezoidal shape having such a curved surface.

Further, two plate glasses may be laminated and used as a laminated glass, or a structure in which plastic is laminated on plate glass may be used.

The thickness of the plate glass used is not particularly limited, and it is general to use a plate glass having a thickness of about 1.5 to 5 mm.

In the case of laminated glass, two plate glasses,
An intermediate resin film sandwiched between the two plate glasses, at least a pair of bus bars provided between the one plate glasses of the two plate glasses, and a transparent conductive film provided so as to connect the pair of bus bars. Composed of.

The intermediate resin film used in the present invention means, in the case of laminated glass, firmly adhering two sheet glasses disposed on both sides thereof, and even when the laminated glass is broken, glass fragments are broken. In general, a polyvinyl butyral resin film, which has an effect of not scattering, is improved in various physical properties such as adhesion, weather resistance and heat resistance is preferably used. The thickness of this intermediate resin film is also not particularly limited, and is generally about 0.2 to 0.9 mm.

The method for producing a laminated glass may be a conventionally known method, and two plate glasses are laminated so as to sandwich a resin film, and a desired laminated glass is produced through steps such as pre-adhesion and autoclave treatment. It

In the present invention, a desired transparent conductive film and a pair of busbars connected to the desired transparent conductive film are provided between two sheet glasses of laminated glass to form an electrically heated glass.
In this case, either one of the plate glasses, preferably, on the surface facing the intermediate resin film of the plate glass that will be located on the indoor side during use, a desired transparent conductive film appropriately selected and a set of bus bars Is preferably provided. Next, the plate glass and another plate glass to be located outside are integrally bonded from both sides of the intermediate resin film.

As the transparent conductive film used in the present invention,
Any of various conventionally known films made of conductive materials can be used, and an appropriate film may be selected according to the purpose of use. Since the applied voltage varies depending on the type of the transparent conductive film used, the bus bar connected to the transparent conductive film is formed so as to be compatible with them.

As a specific example of the transparent conductive film used in the present invention, for example, ITO which is a complex oxide film of indium and tin, which has been used frequently at a relatively low voltage (high current), is used. Examples thereof include a film and a thin film of gold or silver.

Examples of the transparent conductive film used at a high voltage (low current) include an ITO film, a tin oxide film, or a gallium-containing zinc oxide film used by applying a voltage of 288 V to a bus bar. To be The present invention provides a low voltage,
Even if any of the high voltages is applied, the same effect is exhibited.

In order to form these transparent conductive films on the surface of the plate glass, conventionally known methods can be used, for example, vacuum evaporation method, sputtering method, electron beam type heating evaporation method, spray method, CVD method and the like. Any known method can be adopted.

The set of bus bars connected to the transparent conductive film formed by the above-mentioned method and provided for energizing the transparent conductive film is formed by, for example, printing and baking a silver paste. It is formed. The electric heating glass of the present invention is characterized in that the bus bar has a specific shape. That is, in the present invention, the above-mentioned bus bar parallel portion is provided on the upper side portion. The spacing between two busbar elements in the busbar parallel section is 0.
It is preferably about 5 to 30 mm, particularly about 1 to 5 mm.

The bus bar on the lower side has a lower risk of breakage due to its position and length than the bus bar on the upper side. Therefore, the structure of the bus bar on the lower side is not particularly limited, and the conventional one-side power feeding method is also adopted. However, it is preferable to adopt a configuration that achieves the same operation as the safer two-sided power feeding method.

For example, as shown in FIG. 1, like the upper side bus bar, the lower side bus bar is composed of a plurality of lower side bus bar elements, and the plurality of lower side bus bar elements are located on both sides of one side of the transparent conductive film in the lower side portion. 1 near each
The bus bar element has two open ends and extends to the power supply section, and at the connection portion of the bus bar with the transparent conductive film, the plurality of lower side bus bar elements have a parallel portion in a state of being adjacent and facing each other with a space therebetween. In addition, the plurality of lower side bus bar elements may be in contact with the transparent conductive film at the parallel portions.

Further, as shown in FIG. 2, there may be mentioned a configuration in which the plurality of lower side bus bar elements are connected in one power feeding section to form one. The plurality of bus bar elements are used in a plurality of two or more, but it is preferable to use two in practice.

Further, as shown in FIG. 4, it is possible to cite a structure in which a loop-shaped bus bar is in contact with a transparent conductive film as shown in FIG.

When the bus bar on the lower side has a bus bar parallel portion, the distance between the two bus bars is preferably about 0.5 to 30 mm, particularly about 1 to 5 mm.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention, particularly preferred bus bar shapes will be described in detail with reference to the drawings. In the present embodiment, a substantially trapezoidal vehicle windshield glass plate was used.

[Embodiment 1] FIG. 1 shows the shape of a bus bar of this embodiment. In this embodiment, the ends of the pair of bus bars are connected to the positive and negative power supply terminals 5, respectively. Each of the pair of busbars has two elements, one of which has a total of four busbar elements. In the figure, 4 is a plate glass, and the transparent conductive film 3 has a shape substantially similar to the plate glass 4 indicated by a dotted line in the figure. In this example, a film having a multi-layer structure having a gallium-containing zinc oxide layer was used as the transparent conductive film 3.

In the bus bar of this embodiment, the bus bar on the upper side of the glass connected to one pole is composed of two elements 1M and 1S, and the bus bar on the lower side of the glass connected to the other pole is 2M. And 2S respectively, and these four bus bar elements form a set of bus bars. Then, at the respective ends of these bus bars near the left side of the lower side of the glass, they are connected to an external power source via a power supply unit. It is also connected to a current detection mechanism (not shown).

In this embodiment, all the power feeding parts are gathered near the left side of the lower side of the glass.
Provide 1M and 2M terminals near the left side of the lower side of the glass, and
S and 2S terminals are provided near the lower right side of the glass,
You may provide each terminal separately.

In the present embodiment, further, 1M and 1S are partially connected to the transparent conductive film and are arranged so as to have open ends near both sides of one side of the connected transparent conductive film. There is. The portions connected to the transparent conductive films of 1M and 1S form parallel portions which are adjacent to each other with a space provided therebetween.

Similarly, the lower side portions 2M and 2S also have parallel portions partially formed and connected to the transparent conductive film.

That is, in this embodiment, the bus bar is
As shown in FIG. 1, 2 of 1M and 1S are near the upper side of the glass.
The busbar element of the book forms a parallel part,
A parallel portion is formed by two bus bar elements 2M and 2S near the lower side of the glass, and further, two bus bar elements forming the parallel portion are in contact with the upper side and the lower side of the transparent conductive film, respectively.

At this time, the lengths of the elements in the parallel portions, particularly the lengths of the elements inside the parallel portions are set to be substantially the same as the lengths of the upper and lower sides of the transparent conductive film, or preferably slightly longer. It is preferable since the entire surface of the transparent conductive film is energized when energized.

As shown in FIG. 1, two bus bar elements, which are in contact with the upper side of the transparent conductive film, are stretched along the vicinity of the side of the glass, so that the bus bar elements are located at any position on the lower side of the glass. Connected to the power supply in.

Power is supplied from an external power source (eg, a voltage of 288V) to the two bus bar elements 1M and 1S on the upper side and to the two bus bar elements 2M and 2S on the lower side, and through these transparent conductive films. 3 is energized to heat the glass.

In this case, the power is supplied to the transparent conductive film 3 by the busbar elements 1M and 2M located on the inner side, and the power supply by the busbar elements 1S and 2S located on the outer side has only an auxiliary role. When the main busbar element 1M or 2M, which is the main busbar element, is broken at any of the upper, lower, left, and right positions, a current is instantaneously supplied from the auxiliary busbar element 1S or 2S to the transparent conductive film 3. Since the energization is continued, the potential difference does not occur at the damaged portion of the bus bar, and the ignition due to spark or abnormal heating can be suppressed.

Since the rate of increase of the current of the auxiliary bus bar element at this time is very large, if the change of this current is detected, the crack can be detected sensitively. Further, in the present embodiment, since the parallel portion of the bus bar element is formed on both the upper side and the lower side of the glass in the vicinity thereof, a clear current change always occurs even when a crack occurs on the upper side and the lower side. Therefore, it is possible to reliably detect cracks.

On the other hand, as described above, the glass breakage can be detected by detecting the value of the current flowing through the bus bar in the conventional double-sided power supply system shown in FIG. 7, but breakage occurs on the left and right sides. Although it is good in some cases, when cracks occur on the side where the transparent conductive film on the upper side or the lower side is in contact with the bus bar, the change in current is too small to detect the cracks.

[Embodiment 2] FIG. 2 schematically shows the electrically heated glass of this embodiment. As shown in FIG. 2, each of the busbars forming the pair of busbars in this embodiment has the busbar elements 1S and 1M on the upper side as the first embodiment.
It is formed similarly. On the other hand, the busbar element on the lower side has parallel portions 2S and 2M, but is connected by one power feeding unit to form one busbar, and has a structure in which one terminal is connected to an external power supply. The plurality of bus bar elements on the lower side are not connected except for the power feeding section.

[Embodiment 3] FIG. 3 schematically shows the electrically heated glass of this embodiment. As shown in FIG. 3, the respective busbars forming a set of busbars in the present embodiment are connected by one power supply unit to form one busbar, unlike the case of the first embodiment. The plurality of bus bar elements on the upper side are not connected except for the power feeding section. In this embodiment, the bus bar is connected to the external power source by one terminal, respectively, so that the structure can be extremely simplified.

[Embodiment 4] FIG. 4 schematically shows the electrically heated glass of this embodiment. As shown in FIG. 4, the busbar elements 1S and 1M on the upper side of each of the busbars constituting the pair of busbars in this embodiment are formed in the same manner as in the first embodiment.

On the other hand, unlike the case of the first embodiment, the bus bar 2 on the lower side does not form a parallel portion as referred to in the present invention. That is, it is composed of one loop-shaped bus bar, and only the transparent conductive film side portion thereof is connected to the transparent conductive film.
With such a configuration of the lower side bus bar, the area occupied by the lower side bus bar can be reduced.

[Embodiment 5] FIG. 5 schematically shows the electrically heated glass of this embodiment. In the present embodiment, the crack detection means 7 is added to the bus bar having the same structure as that of the first embodiment.
Is provided. The crack detecting means 7 is connected to a crack detecting mechanism (not shown). With such a configuration, the occurrence of cracks can be detected more accurately and the safety is improved.

For example, in the case of Example 1, if the inner bus bar element 1M or 2M in contact with the transparent conductive film 3 is completely cut off, a current detection mechanism (not shown) operates and power supply is stopped. If only the outer busbar element 1S or 2S is broken (because it is an auxiliary busbar, no abnormality occurs in the glass itself), the change in the current flowing through the busbar is small and the crack detection mechanism may not work sufficiently. There is.

In the present embodiment, in preparation for such a case, the crack detecting conductor 7 is provided at an appropriate position as the crack detecting means, so that the fluctuation of the voltage generated in the bus bar or the transparent conductive film 3 can be quickly detected. . Further, the current to the transparent conductive film 3 can be cut off in accordance with this detection result.

As the crack detecting means, specifically,
For example, crack detection means wired so as to detect voltage fluctuations occurring in the bus bar or the transparent conductive film, or crack detection means wired so as to detect fluctuations in current flowing in the bus bar or the transparent conductive film. Is mentioned.

This will be described in detail with reference to FIG. 5. In this embodiment, the shape of the bus bar is the same as that of the embodiment shown in FIG. 1, and further, a crack detecting conductor is provided near the terminals 5 of the bus bars 1 and 2. The crack detection wire 7 is connected along the outside of each bus bar, and the crack detection wire 7 is laid along the outside of each bus bar so that the crack detection wire 7 is arranged near all peripheral portions of the glass. Thereby, even if any of the four pieces of glass is cracked, it is possible to instantly know the occurrence of the crack by the crack detection lead wire.

That is, first, the voltage and resistance value of the detection lead wire 7 while the transparent conductive film 3 is energized are detected. Furthermore, by measuring the fluctuation state of these measured values,
Mutations in voltage and resistance due to mutations such as cutting and breakage that occur in bus bars and crack detection conductors can be easily detected.

Further, by interlocking the detection result with the control of the energization to the transparent conductive film 3, it is possible to quickly take measures such as the interruption of the energization in the case of the occurrence of cracks.
It can be a safer energized heating glass.

As the crack detecting means used at this time,
In addition to the crack detecting means wired so as to detect the voltage fluctuation as described above, a crack detecting means wired so as to detect the fluctuation of the current flowing through the bus bar or the transparent conductive film may be used.

[0065]

EFFECTS OF THE INVENTION The electrically heated glass of the present invention does not cause sparks or the like at the ruptured portion even if the crack occurs at any place of the electrically heated glass and the bus bar ruptures, and further has sufficient crack detection sensitivity. Therefore, the safety is further improved and it is suitable for automobiles and the like.

[Brief description of drawings]

FIG. 1 is a schematic view (a) and a partially enlarged view (b) showing an example of an electrically heated glass of the present invention.

FIG. 2 is a schematic view showing another example of the electrically heated glass of the present invention.

FIG. 3 is a schematic view showing another example of the electrically heated glass of the present invention.

FIG. 4 is a schematic view showing another example of the electrically heated glass of the present invention.

FIG. 5 is a schematic view showing another example of the electrically heated glass of the present invention.

FIG. 6 is a schematic view showing a conventional electrically heated glass.

FIG. 7 is a schematic view showing a conventional electrically heated glass.

FIG. 8 is a schematic diagram showing a conventional electrically heated glass.

[Explanation of symbols]

 1: Upper side bus bar 1M: One bus bar element forming the bus bar 1 1S: Other bus bar element forming the bus bar 1 2: Lower side bus bar 2M: One bus bar element forming the bus bar 2 2S: Configuring bus bar 2 Other busbar elements 3: Transparent conductive film 4: Plate glass 5: Power supply terminal 6: Crack 7: Detection lead wire

Claims (7)

[Claims] 1. A set of busbars comprising an upper side busbar and a lower side busbar provided on each of the upper and lower sides of a plate glass, and a transparent conductive material provided on the surface of the plate glass so as to connect between the pair of busbars. In an electrically heated glass composed of a film, the upper side bus bar is composed of a plurality of upper side bus bar elements, and the plurality of upper side bus bar elements are respectively provided with one opening near both sides of the upper side of the transparent conductive film in the upper side of the glass sheet. It has an end and extends to the power feeding portion, and in the connection portion of the upper side bus bar with the transparent conductive film, the plurality of upper side bus bar elements have a parallel portion in a state of being adjacent and facing each other with a space therebetween. An electrically heated glass, wherein a plurality of upper side bus bar elements are in contact with the transparent conductive film at the parallel portions. 2. The electrically heated glass according to claim 1, wherein the upper side bus bar has a plurality of bus bar elements connected to each other at one power feeding portion. 3. The lower side bus bar element is composed of a plurality of lower side bus bar elements, and the plurality of lower side bus bar elements each have one open end near both sides of one side of the transparent conductive film in the lower side portion of the sheet glass and a power feeding section. And the plurality of lower side busbar elements have parallel portions in a state where they are adjacent to each other and are spaced apart from each other at the connection portion of the lower side busbar with the transparent conductive film. The electrically heated glass according to claim 1 or 2, wherein the element is in contact with the transparent conductive film at the parallel portion. 4. The electrically heated glass according to claim 3, wherein the lower side bus bar has a plurality of bus bar elements connected at one power feeding portion. 5. The electrically heated glass according to claim 1, wherein the lower side bus bar has a loop shape, and a part of the loop bus bar is in contact with the transparent conductive film. 6. The electrically heated glass according to claim 1, wherein a crack detecting wire is provided around the plate glass. 7. A set of bus bars consisting of an upper side bus bar and a lower side bus bar provided on each of the upper and lower sides of an automobile sheet glass, and provided on the surface of the sheet glass so as to connect between the pair of bus bars. In an electrically heated glass composed of a transparent conductive film, the upper side bus bar is composed of a plurality of upper side bus bar elements, and the plurality of upper side bus bar elements are respectively provided on the upper side of the glass sheet in the vicinity of both sides of the upper side of the transparent conductive film. It has two open ends and is extended to the power supply section, and in the connection portion of the upper side bus bar with the transparent conductive film, the plurality of upper side bus bar elements are arranged in parallel with each other with a space therebetween. A plurality of upper side bus bar elements are in contact with the transparent conductive film in the parallel portion, Nest.