JPH0517061B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an electrically conductive transparent member for automobiles, and particularly to an electrically conductive transparent member for automobiles suitable for automobile window glasses and mirrors.

[Prior art]

In order to remove fog caused by water droplets and ice adhering to automobile window glasses and mirrors, defroster devices and hot wire defroster devices, which use fans to blow hot air onto the window glass surfaces, have conventionally been used.

However, the defroster device has the following problems.

First, a large capacity defroster device is required.

Second, since the defroster device is integrated with the air conditioner, when the defroster device is activated, the warm air blown out from the defroster device raises the car's room temperature more than necessary, making it difficult to maintain the temperature inside the car at a comfortable temperature. be.

Third, the defroster device makes a lot of noise when it operates.

Fourth, when the engine coolant is at a low temperature, it takes time to defog or defrost.

In addition, the hot wire defogger has the following problems.

First, the horizontal stripes that appear when the hot-wire defogger is installed are unsightly.

Secondly, the defrosting or defrosting pattern also becomes a horizontal striped pattern, and visibility is not sufficient.

Therefore, in order to solve this problem, in place of the conventional defroster device or hot wire defroster,
Transparent conductive glass is being considered in which a transparent conductive thin film is formed over the entire glass to serve as a transparent heater film.

By the way, conventional attempts have been made to form a transparent conductive thin film over the entire glass. However, if a transparent conductive thin film is formed over the entire glass, the entire glass will be heated uniformly, there will be no temperature concentration, and it will take a long time to remove the fog.

Therefore, it has been desired to devise a method for preferentially defrosting or defrosting areas where it is desired to immediately ensure visibility.

[Purpose of the invention]

The present invention was made based on the above request, and an object of the present invention is to change the film quality depending on the location while keeping the thickness of the transparent conductive thin film uniform in a conductive transparent member used for automobile window glass etc. By doing so, it is possible to quickly secure the visibility of the part that most urgently needs to be secured.

[Structure of the invention]

According to the present invention, this object is achieved by the following electrically conductive transparent member for automobiles.

That is, the electrically conductive transparent member for automobiles of the present invention is an electrically conductive transparent member used for automobile window glass, etc., and includes a substantially rectangular transparent substrate and one set of four sides of the transparent substrate that are opposite to each other. It consists of a pair of electrodes provided along the sides of the substrate, and a transparent conductive thin film connected to these electrodes and provided over almost the entire surface of the transparent substrate.The film quality of this transparent conductive thin film changes depending on the location. It is characterized in that the resistance of the transparent conductive thin film in a portion of the transparent substrate where it is desired to quickly defrost or defrost is different from the resistance of other portions due to changes in film quality.

The present invention focuses on the fact that in automobile window glass, etc., the part where the defogging effect is most needed differs depending on the type of window glass, and focuses the current density on the part where it is necessary to ensure quick visibility. The objective is to obtain a quick field of view.

The electrically conductive transparent member for automobiles of the present invention can be applied to window glasses such as windshield glass, rear window glass, side window glass, quarter window glass, door mirrors, side mirrors, and the like.

In the present invention, transparent substrates include transparent resins such as polyacrylonitrile and polycarbonate;
Glass or the like can be used.

Transparent conductive thin films include indium oxide (In ₂ O ₃ ), indium oxide-tin solid solution (ITO) in which tin (Sn) or fluorine (F) is used as a dopant in indium oxide, indium oxide-fluorine solid solution, Using tin dioxide (SnO ₂ ), a tin dioxide-fluorine solid solution using fluorine (F), phosphorus (P) or antimony (Sb) as a dopant in this tin dioxide, a tin dioxide-phosphorus solid solution, and a tin dioxide-antimony solid solution. Furthermore, it is possible to use a metal (alloy) thin film made of gold ((Au), silver (Ag), copper (Cu), chromium (Cr), palladium (Pd), rhodium (Rh)) or an alloy thereof. I can do it.

The value of the sheet resistance of the transparent conductive thin film is preferably 5Ω/□ or less in consideration of the optimum amount of heat generation for the defogging effect and the electromotive force of the battery power supply. Therefore, the appropriate thickness of the transparent conductive thin film is about 0.5 to 1 μm. if,
If the film thickness becomes thicker than this, it will adversely affect the adhesion and the durability of the film itself. If it is thinner than this, the resistance value will be too large and almost no current will flow, making it impossible for a battery power source to provide an effective defogging function.

When using a metal thin film, it is desirable to have a thickness of about several hundred angstroms because if it becomes thick, it will be colored.

In the present invention, the thickness of the transparent conductive thin film is uniform throughout. This transparent conductive thin film is formed on a transparent substrate by a vacuum film forming method such as a vacuum evaporation method, sputtering, or ion plating, or a chemical vapor deposition (CVD) method such as a hydrolysis reaction or a thermal decomposition reaction.

In the present invention, the quality of the transparent conductive thin film varies depending on the location on the transparent substrate. As the film quality changes, the resistance changes, and as a result, by appropriately selecting the part where the film quality is changed, it is possible to concentrate current on the part where it is desired to rapidly defrost or defrost, thereby causing local heat generation.

Methods for changing the film quality of this transparent conductive thin film include changing the composition of the transparent conductive thin film using reactive sputtering, applying hydrogen peroxide, or applying acid or alkali. Can be used.

On a pair of opposing sides of the transparent conductive thin film,
A pair of electrodes is preferably provided on the window glass at a position that is not visible from the outside when the window glass is closed.

The electrode functions as a terminal that supplies current to the transparent conductive thin film. As the electrode, a low-resistance material such as aluminum (Al), nickel (Ni), silver (Ag), chromium (Cr), etc. can be used. These electrodes are formed by vacuum evaporation, sputtering, ion plating, printing and baking of conductive paste, and the like. Note that a lead wire is attached to the electrode by soldering, brazing, etc., and this lead wire is connected to an on-vehicle battery power source or the like via a switch.

A transparent protective film may be formed on the transparent conductive thin film for insulation and protection. As this transparent protective film, zirconium oxide (ZrO ₂ ), alumina (Al ₂ O ₃ ), etc. can be used.

Furthermore, an antireflection film may be formed on this transparent protective film. As this antireflection film, silicon dioxide or the like can be used. Note that the transparent protective film can also be used as an antireflection film.

The above-mentioned transparent protective film and antireflection film can be formed by a vacuum film forming method such as a vacuum evaporation method, ion plating, or sputtering.

[Action of the invention]

According to the electrically conductive transparent member for automobiles of the present invention, the thickness of the transparent electrically conductive thin film is uniform throughout the film, but the film quality varies depending on the location, and the resistance of parts where rapid defogging is particularly required is higher than that of other parts. It is made larger or smaller, and the current is concentrated in this part. At this time, the film quality can be determined, for example, by applying hydrogen peroxide to replenish oxygen defects and increasing the resistance, or by applying acid or alkali to deteriorate the transparent conductive thin film material and increase the resistance. You may do so. As a result, defogging begins quickly in the area where the current is concentrated, and the range of defogging expands from there toward the surrounding area.

〔Effect of the invention〕

According to the conductive transparent member for automobiles according to the present invention, the following effects are achieved.

(b) The heat generation pattern is formed in such a way that the current density is concentrated in areas where quick visibility is required, so not only does it prevent fogging due to water droplets, etc., but it also easily prevents ice from forming on the outside of the glass, and quickly melts the ice. It is possible to have a defogging function with a quick start-up mainly in areas where you want to maintain visibility.

(b) Because the heat is generated by the electric resistor on the glass surface, defogging is faster when the engine coolant is low compared to methods using conventional defroster devices.
Also, no noise is generated.

(c) Visibility is improved because horizontal stripes do not occur as with conventional hot-wire defogger.

〔Example〕

Next, preferred embodiments of the present invention will be described with reference to the drawings.

[First Example] This example shows an example in which the present invention is applied to a rear window glass.

Here, FIG. 1 is a schematic configuration diagram showing an outline of a sputtering vacuum chamber used in a first embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of an automobile rear window glass according to a first embodiment of the present invention. , FIG. 3 is an explanatory diagram showing how fogging is removed by electrical heating.

Transparent substrate 1 in the shape of automobile rear window glass
After washing thoroughly with an organic solvent and pure water, silver paste 2 containing glass frit as an electrode was screen printed on the left and right sides as shown in Figure 2.
After drying at 150℃ for 20 minutes, bake at 500℃ for 30 minutes.
At this time, the difference in level between the electrode surface and the glass surface (usually
(approximately 50 μm), polish the surface using an abrasive containing fine alumina powder to eliminate the step and create a gently sloped surface.

Subsequently, the entire transparent substrate 1 was placed in a sputtering vacuum chamber 3 as shown in FIG. 1, and a transparent conductive thin film was formed by sputtering. First, a transparent substrate 1 is installed on the anode side, and the cathode side is used as an evaporation source.
An ITO sintered target 4 containing 10 wt% SnO ₂ in In ₂ O ₃ was used. Then, the inside of the vacuum chamber 3 was
After exhausting to about 10 ^-5 Torr, argon gas is introduced to about 2×10 ^-3 Torr. In this state, as shown in FIG. 1, while introducing oxygen from a pair of oxygen gas introduction tubes 5 opening at the side of the transparent substrate 1
A sputtering voltage of 1 kW is applied to form ITO6 as a transparent conductive thin film with a thickness of approximately 1 μm. Next, electrode 2
A terminal for taking out a lead wire (not shown) is soldered to the end of the terminal.

As a result, an automobile rear window glass 7 shown in FIG. 2 was obtained. In FIG. 2, the darker the hatched area, the more ITO is filled with oxygen vacancies, and the higher the resistance. After spraying steam on this automobile rear window glass 7 to make it foggy, when electricity was applied to the transparent conductive thin film, the result was as shown in Figure 3a.
As shown in ~c, the fog was removed in a short time mainly in areas with low resistance.

(Second Example) The application was applied to the side window glass instead of the rear window glass, the electrodes were provided on the top and bottom sides instead of the left and right sides, and the oxygen gas was applied to the transparent substrate 1.
A side window glass 8 coated with an ITO film was obtained in substantially the same manner as in the first embodiment except that the ITO film was uniformly introduced thereon. Subsequently, hydrogen peroxide solution was applied to the diagonally hatched portion of the side window glass 8 shown in FIG.

As a result, compared to the cross-hatched portion shown in FIG. 4, oxygen vacancies in the diagonally hatched portion were replenished by the hydrogen peroxide solution, and the resistance became greater than that in the cross-hatched portion. After fogging the side window glass 8 by spraying steam on it, electricity was applied to the transparent conductive thin film. The haze has been removed.

(Third Example) Electrodes were provided on the upper and lower sides of the transparent substrate 1,
An ITO film was formed on the transparent substrate 1 in substantially the same manner as in the first example except that oxygen gas was uniformly introduced onto the transparent substrate 1. Thereafter, as shown in FIG. 6, extremely diluted hydrochloric acid was applied to the intermediate part 1b sandwiched between the upper part 1a and the lower part 1c of the transparent substrate 1. As a result, the intermediate portion 1 of the transparent substrate 1
b (the cross-hatched area) was degraded by dilute hydrochloric acid, and the resistance of the transparent conductive thin film in the middle part 1b was greater than that in the upper part 1a and the lower part 1c. After fogging the rear window glass 7 by spraying steam on it, electricity was applied to the transparent conductive thin film. As the middle part of the rear window glass 7 had a large resistance, a lot of heat was generated in the middle part, as shown in FIGS. 7 a to c. The cloudiness was removed within a short period of time, mainly in this middle area.

Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various embodiments within the scope of the claims. .

For example, although the embodiment shows an example in which the present invention is applied to a rear window glass and a side window glass, it can also be applied to other window glasses and mirrors.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the outline of the sputtering vacuum chamber used in the first embodiment of the present invention, FIG. 2 is a schematic diagram of the rear window glass for an automobile according to the first embodiment of the present invention, and FIG. The figure is an explanatory diagram showing how fogging is removed by electrical heating, FIG. 4 is a schematic diagram of the structure of an automobile side window glass according to the second embodiment of the present invention, and FIG. 5 is a diagram showing how fogging is removed by electrical heating. FIG. 6 is a schematic configuration diagram of an automobile rear window glass according to a third embodiment of the present invention, and FIG. 7 is an explanatory diagram showing how fogging is removed by electrical heating. 1... Transparent substrate, 1a... Upper part, 1b... Middle part,
1c...lower part, 2...silver paste (electrode), 3...sputtering vacuum chamber, 4...indium-tin alloy (evaporation source), 5...oxygen gas introduction tube, 6...ITO (transparent conductive thin film), 7... Rear window glass, 8...Side window glass.

Claims (1)

[Scope of Claims] 1. A conductive transparent member used for automobile window glass, etc., comprising: a substantially rectangular transparent substrate; and a set of opposing sides of the transparent substrate. It consists of a pair of electrodes, and a transparent conductive thin film connected to these electrodes and provided over almost the entire surface of the transparent substrate. 1. A conductive transparent member for an automobile, characterized in that the resistance of the transparent conductive thin film in a portion to be rapidly defrosted or defrosted is different from the resistance in other portions due to a change in film quality.