JPH11268618A - Mirror with heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve removing performance of water drops and the like from a mirror surface without restricting heat generation by providing one or more pair of electric supply electrode on a reflective and heat generating resistor film covering a non- conductive mirror substrate reverse face and adjusting the sheet resistance values of a supplementary electrode and the resistor film to a specific ratio. SOLUTION: At least a pair of electric supply electrodes 3a, 3b are formed on a reflective and heat generating resistor film formed on a reverse face of a non- conductive mirror substrate 1 with metal film such as titanium by vacuum deposition. The electric supply electrodes 3a, 3b are directly connected with power source to supply electricity to a resistor film 2 so as to generate heat. Supplementary electrodes 5a, 5b electrically coupled with the electric supply electrodes via the reflective and heat generating resistor film 2 are provided between the electric supply electrodes 3a, 3b. The sheet resistance values of the supplementary electrodes 5a, 5b are 1 to 30% of the sheet resistance value of the resistor film 2. Accordingly, temperature distribution on the mirror surface is made uniform without deteriorating the uniformity of current distribution of the heat generating resistor 2. As a result, an efficient defogging and removing performance of water drops, frost, and the like are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror with a heater for anti-fogging or for removing water droplets, raindrops, dew, ice and the like adhering to the surface of a mirror. About.

[0002]

2. Description of the Related Art A mirror with a heater is used to prevent water droplets adhering to a rearview mirror or the like during running of a vehicle during rainfall or snowfall.
It is used to heat and remove snow, ice, etc., and to prevent water droplets from re-adhering or re-freezing, making it easier to see behind and ensuring driving safety. . In particular, in this type of mirror, it is possible to remove water droplets and ice efficiently by making the heating temperature distribution on the mirror surface as uniform as possible. In order to realize this, for example, in Japanese Patent Application Laid-Open No. 61-200051, a non-conductive substrate, a reflective film made of an electric resistive material coated on the surface of the substrate and generating heat by passing an electric current, In a heater-covered mirror body provided with a pair of power supply electrodes provided on a reflective film at an end, an auxiliary electrode having a sufficiently small resistance value is provided between a pair of power supply electrodes provided at an end of the mirror body. It has been proposed that the provision of (1) makes it possible to very easily create a desired heating temperature distribution according to the intended purpose and shape of the heater-coated mirror.

[0003]

However, Japanese Patent Application Laid-Open No.
The mirror with a heater described in Japanese Patent Application Laid-Open No. 1-200051 has a structure in which, when the sheet resistance value of the provided auxiliary electrode is extremely lower than the sheet resistance value of the reflection film, the auxiliary electrode has a low resistance value. The heat generation at the part where the is arranged is suppressed and it is not heated, and water droplets, raindrops,
There is a problem that the performance of removing dew and ice is rather deteriorated.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a non-conductive mirror substrate and a reflective film and a heating resistor film coated on the back surface of the substrate. Alternatively, a reflective film and a heating resistor film, at least one pair of power supply electrodes provided on the reflective film and the heating resistor film or the heating resistor film, and on the reflective film and the heating resistor film or the heating resistor film A mirror with a heater, comprising: a mirror provided with a sheet resistance value of 1% to 30% of a sheet resistance value of the reflection film / heating resistor film or the heating resistor film. Is what you do.

The details will be described below. FIG. 1 is a schematic rear view of a mirror with a heater used in an automobile rearview mirror according to a first embodiment of the present invention, and FIG. 2 is a schematic sectional view thereof. The non-conductive mirror substrate 1 is made of a transparent material such as glass or an acrylic plate, and its cross section has a flat or curved plate shape. On the back surface of the mirror substrate 1, a reflection film / heating resistor film 2 is formed. The reflection film / heating resistor film 2 is formed by forming a metal thin film of titanium, chromium, nickel-chromium alloy, aluminum-titanium alloy or the like by a sputtering method or a vacuum evaporation method. The reflective film / heat generating resistor film 2 may have a configuration other than the single-layer structure in which the reflective film and the heat generating resistor film are used as described above. That is, a two-layer structure including a first layer film functioning as a reflective film and a second layer film functioning as a heating resistor film can be employed. In this case, the first layer is formed of a metal thin film of aluminum, chromium, nickel, a nickel-chromium alloy, nickel-phosphorus, or the like by a sputtering method, a vacuum evaporation method, a plating method, or the like. A metal thin film of silicide, chromium silicide, tantalum nitride, titanium carbide, tungsten carbide, niobium boride, an iron-chromium-aluminum alloy, or the like can be formed by a sputtering method, a vacuum evaporation method, a plating method, or the like. Further, an insulating layer may be provided between the reflection film and the heating resistor film so that the reflection film and the heating resistor film are independently formed so as not to be electrically connected. In this case, as the reflective film, a metal thin film such as aluminum, chromium, nickel, nickel-chromium alloy, nickel-phosphorus is formed by a sputtering method, a vacuum evaporation method, a plating method, or the like, and the insulating layer is formed of silica or the like, As the heating resistor film, a thin metal film such as titanium, titanium silicide, chromium silicide, tantalum nitride, titanium carbide, tungsten carbide, niobium boride, iron-chromium-aluminum alloy is formed by a sputtering method, a vacuum evaporation method, a plating method, or the like. Can be formed. The sheet resistance value of the reflection film and the heating resistor film or the heating resistor film is preferably 2 to 20 Ω / □ in consideration of the power output on the vehicle side.

[0006] At least a pair of power supply electrodes 3a and 3b are formed on the reflection film / heating resistor film 2. The power supply electrodes 3a and 3b are formed to be directly connected to the power supply and to supply electricity to the reflective film / heat generating resistor film 2 to generate heat. These power supply electrodes 3a, 3b
Can be formed by printing a silver paste, a copper paste, or the like on the reflection film / heating resistor film 2 or by directly forming a thin metal film of silver, copper, nickel, or the like by sputtering or electrolytic etching. The method can be used. On the power supply electrodes 3a and 3b, by soldering or the like,
The lead wires 4a and 4b are connected.
a and 4b are connected to a power supply. Further, auxiliary electrodes 5a, 5b electrically connected to the power supply electrodes 3a, 3b via the reflective film and the heat generating resistor film 2 are provided between the power supply electrodes 3a, 3b on the reflective film and the heat generating resistor film 2. Are formed. The auxiliary electrodes 5a and 5b are formed by printing or painting a carbon paste, a carbon-silver paste, a copper paste, or the like on the reflective film / heating resistor film 2, or by sputtering or electrolytic etching a metal thin film. Can be formed. Here, the sheet resistance value of the auxiliary electrodes 5a and 5b needs to be 1% to 30% of the sheet resistance value of the reflection film / heating resistor film 2. This is because if the sheet resistance of the auxiliary electrode is set to less than 1% of the sheet resistance of the reflection / heating resistor film or the heating resistor film, the resistance of the auxiliary electrode is too low to suppress heat generation. Is not heated,
If the sheet resistance value of the auxiliary electrode exceeds 30% of the sheet resistance value of the heat generating resistor film or the heat generating resistor film, the temperature distribution becomes non-uniform. The resistance difference between the heating resistor film and the heating resistor film becomes smaller, the effect of inducing current to the auxiliary electrode is weakened, and the current distribution of the reflecting film and the heating resistor film or the heating resistor film cannot be controlled, resulting in uneven temperature distribution. Because it becomes. In order to make the sheet resistance of the auxiliary electrode a value of 1% to 30% of the sheet resistance of the reflection film and the heating resistor film, the material of the auxiliary electrode is selected and the film thickness is adjusted. A more preferable value of the sheet resistance of the auxiliary electrode is 5% to 30% of the sheet resistance of the reflection film and the heating resistor film.

In the present embodiment, two auxiliary electrodes 5a and 5b are formed in a stripe shape.
It is also possible to change the formation position and shape of the auxiliary electrode, the number of auxiliary electrodes, and the like according to the mirror shape and the desired temperature distribution state of the mirror. It is particularly preferable that the auxiliary electrode is formed so that the mirror substrate extends over a region heated by the power supply electrode and a region not heated by the power supply electrode. Further, it is also possible to form a temperature distribution in the auxiliary electrode by a method such as providing a film thickness distribution in the auxiliary electrode, or overlapping auxiliary electrodes having different resistance values on the auxiliary electrode. A temperature detecting element may be provided for controlling the mirror heating, or a coating with an insulating moisture-proof material may be provided for improving the durability.

FIG. 3 is a schematic rear view of a mirror with a heater used in a rearview mirror for an automobile according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in that the mirror substrate 11 has a different shape, and the pair of power supply electrodes 13a and 13b
Are formed along the upper and lower sides of the auxiliary electrode 15.
a and 15b are formed along the upper and lower sides of the mirror substrate 11 in the same manner as the power supply electrodes 13a and 13b, and are outside the area surrounded by the power supply electrodes 13a and 13b (the area not heated by the power supply electrodes) ( (The right part of the figure) is clearly thicker, and a thermostat 16 as a temperature detecting element and a thermal fuse 17 are connected between the power supply electrode 13a and a power supply (not shown). This is the same as in the first embodiment.

[0009]

In the mirror with heater of the present invention, the sheet resistance of the auxiliary electrode is set to 1% to 30% of the sheet resistance of the reflection film and the heating resistor film or the heating resistor film. In addition, since the current distribution of the reflecting film and the heating resistor film or the heating resistor film can be controlled and the auxiliary electrode portion can be heated by having a certain resistance, the temperature distribution on the mirror can be made uniform. .

[0010]

The present invention will be described below in detail with reference to examples. Example 1 In the first embodiment, R = 1 as the mirror substrate 1
Using a deformed glass substrate having a curved surface of 400 mm, a titanium film having a thickness of about 55 nm is formed as a reflective film and a heating resistor film 2 by a sputtering method, and the feed electrodes 3a and 3b are formed to a thickness of about A mirror with a heater was formed by printing a copper paste so as to have a thickness of 75 μm, and forming the auxiliary electrodes 5a and 5b by printing a carbon-silver paste so as to have a thickness of about 130 μm. 10. The sheet resistance of each of the reflection film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 5a, 5b of the mirror with heater obtained in Example 1 was measured by a four-terminal method.
0Ω / □, 0.04Ω / □, 0.05Ω / □, 0.12
Ω / □ and 0.11 Ω / □.

Example 2 In the first embodiment, R = 1
Using a deformed glass substrate having a curved surface of 400 mm, a titanium film having a thickness of about 60 nm is formed as a reflective film and a heating resistor film 2 by a sputtering method. A mirror with a heater was formed by printing a copper paste so as to have a thickness of 50 μm, and forming the auxiliary electrodes 5a and 5b by printing a copper paste so as to have a thickness of about 30 μm. When the sheet resistance value of each of the reflection film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 5a, 5b of the mirror with heater obtained in Example 2 was measured by a four-terminal method, 10.0 Ω / □ was obtained.
0.06Ω / □, 0.06Ω / □, 0.20Ω / □,
It was 0.19 Ω / □.

Example 3 In the first embodiment, R = 1
Using a glass substrate of a different shape having a curved surface of 400 mm, a titanium film having a thickness of about 50 nm is formed as a reflective film and a heating resistor film 2 by a sputtering method. A copper film is formed by a sputtering method so as to have a thickness of 250 nm.
An aluminum film was formed by a sputtering method so that a and b had a thickness of about 50 nm, and a mirror with a heater was prepared. When the sheet resistance value of each of the reflection film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 5a, 5b of the mirror with heater obtained in Example 3 was measured by a four-terminal method, 12.5Ω / □ was obtained. 0.08Ω / □, 0.08
Ω / □, 0.62Ω / □, 0.62Ω / □.

Embodiment 4 In the first embodiment, as the mirror substrate 1, R = 1
A two-layer film of a nickel-chromium alloy film having a film thickness of about 70 nm and a titanium film having a film thickness of about 80 nm as a reflective film and a heating resistor film 2 using a glass substrate of a different shape having a curved surface of 400 mm. Are formed by sputtering, and the power supply electrodes 3a and 3b are formed by printing silver paste so that the film thickness becomes about 75 μm, and the auxiliary electrodes 5a and 5b are formed.
Was formed by printing a carbon paste so that the film thickness was about 80 μm, to prepare a mirror with a heater. The sheet resistance of each of the reflection film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 5a, 5b of the mirror with heater obtained in Example 4 was measured by a four-terminal method, and was 4.3.
Ω / □, 0.02Ω / □, 0.02Ω / □, 0.41Ω
/ □, 0.42Ω / □.

Embodiment 5 In the first embodiment, R = 1
Using a deformed glass substrate having a curved surface of 400 mm, a titanium film having a thickness of about 40 nm is formed as a reflective film and a heating resistor film 2 by a sputtering method. A mirror with a heater was produced by forming a copper paste so as to have a thickness of 30 μm and forming a nickel-chromium alloy film by a sputtering method so as to have a thickness of about 200 nm as the auxiliary electrodes 5a and 5b. When the sheet resistance of each of the reflection film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 5a, 5b of the mirror with heater obtained in Example 5 was measured by a four-terminal method, 15.8Ω / □ was obtained. 0.20Ω / □, 0.1
8 Ω / □, 3.16 Ω / □, 3.19 Ω / □.

Embodiment 6 In the first embodiment, as the mirror substrate 1, R = 1
Using a deformed glass substrate having a curved surface of 400 mm, a titanium film having a thickness of about 40 nm is formed as a reflective film and a heating resistor film 2 by a sputtering method. Mirrors with heaters were formed by printing copper paste so as to have a thickness of 90 μm and applying carbon paste so as to have a thickness of about 8 μm as auxiliary electrodes 5a and 5b. The sheet resistance of each of the reflecting film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 5a, 5b of the mirror with heater obtained in Example 6 was measured by the four-terminal method.
5.3Ω / □, 0.03Ω / □, 0.03Ω / □, 4.
It was 58Ω / □ and 4.55Ω / □.

Embodiment 7 In the second embodiment, R = R
A deformed glass substrate having a curved surface of 1400 mm was used.
The power supply electrodes 13a and 13b are formed by printing a copper paste so as to have a thickness of about 75 μm, and the auxiliary electrode 15 is formed.
A and 15b were formed by printing a copper paste so as to have a film thickness of about 40 μm to prepare a mirror with a heater. The reflecting film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 7a of the mirror with heater obtained in the seventh embodiment.
7b was measured by the four-terminal method to find that 3.0 Ω / □, 0.04 Ω / □, 0.04 Ω / □,
0.16Ω / □ and 0.17Ω / □.

Comparative Example 1 In the first embodiment, R = 1
A titanium film having a thickness of about 90 nm is formed as a reflective film and a heating resistor film 2 by a sputtering method using a deformed glass substrate having a curved surface of 400 mm, and the power supply electrodes 3a and 3b are formed to a thickness of about A mirror with a heater was formed by forming the auxiliary electrodes 5a and 5b by printing a copper paste so as to have a thickness of about 75 μm. When the sheet resistance value of each of the reflection film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 5a, 5b of the mirror with heater obtained in Comparative Example 1 was measured by the four-terminal method, it was 7.5Ω / □. 0.
04Ω / □, 0.04Ω / □, 0.04Ω / □, 0.0
It was 4Ω / □.

Comparative Example 2 In the first embodiment, R = 1
Using a deformed glass substrate having a curved surface of 400 mm, a titanium film having a thickness of about 55 nm is formed as a reflective film and a heating resistor film 2 by a sputtering method, and the feed electrodes 3a and 3b are formed to a thickness of about A mirror with a heater was formed by forming a copper paste so as to have a thickness of 75 μm, and forming auxiliary electrodes 5a and 5b by applying a carbon paste so as to have a thickness of about 8 μm. The sheet resistance value of each of the reflection film / heating resistor film 2, the power supply electrodes 3a, 3b, and the auxiliary electrodes 5a, 5b of the mirror with heater obtained in Comparative Example 2 was measured by a four-terminal method to find 11.2Ω /.
□, 0.04Ω / □, 0.04Ω / □, 4.50Ω /
□, 4.48Ω / □.

Comparative Example 3 FIG. 4 is a schematic rear view of a mirror with a heater of Comparative Example 3. In Comparative Example 3, a mirror with a heater was prepared in the same manner as in Example 7, except that the auxiliary electrode was omitted. The sheet resistance value of each of the reflection film / heating resistor film 12 and the power supply electrodes 13a and 13b of the mirror with heater obtained in Comparative Example 3 was measured by the four-terminal method.
Ω / □, 0.04 Ω / □, and 0.04 Ω / □.

Comparative Example 4 FIG. 5 is a schematic rear view of a mirror with a heater of Comparative Example 4. Comparative Example 4 is different from Comparative Example 3 in that the lower power supply electrode 13
A mirror with a heater was manufactured in the same manner as in Comparative Example 3, except that the region that could not be heated by the power supply electrodes 3a and 3b was reduced by extending b to the right. The sheet resistance value of each of the reflection film / heating resistor film 12 and the power supply electrodes 13a and 13b of the mirror with heater obtained in Comparative Example 4 was measured by a four-terminal method, and was 3.0 Ω / □, 0.04 Ω / □.
0.04Ω / □.

With respect to the mirrors with heaters obtained in the above Examples 1 to 7 and Comparative Examples 1 to 4, an energization test was conducted at the same power under normal temperature and normal humidity environment, and the mirror surface temperature was measured by thermography. The results are shown in FIGS. 6 to 15 are schematic diagrams of thermography, Examples 1 to 7 correspond to FIGS. 6 to 12, Comparative Examples 1 and 2 correspond to FIGS. 13 and 14, and Comparative Examples 3 and 14. 4
Corresponds to FIG.

6 to 15, 8, 8a, 8b, 8
The region c is a range where the surface temperature of the mirror is within ± 5 ° C. with respect to the average temperature of the mirror surface, and the region 9 is a range where the average temperature of the mirror surface is -5 ° C. or less, 10,
Regions 10a and 10b are ranges where the average temperature of the mirror surface is + 5 ° C. or higher. Table 1 shows the ratio of the area of each region to the surface area of the mirror.

[0023]

[Table 1]

In Comparative Example 4, the region 10a was significantly heated to a temperature at which there was a risk of burns due to current concentration.

The area within the average mirror temperature of ± 5 ° C. is 80%.
In the above case, the mirror surface is almost uniformly heated, and as a mirror with a heater, the anti-fog performance and the removal performance of water droplets, frost, etc. are excellent, and particularly, the area within the average mirror temperature of ± 5 ° C is 85%.
In the above cases, very excellent antifogging and water / frost removal performance were exhibited.

[0026]

According to the mirror with heater according to the present invention, the sheet resistance of the auxiliary electrode is 1% to 30% of the sheet resistance of the reflection film and the heating resistor film or the heating resistor film.
It prevents the temperature from lowering on the auxiliary electrode without impairing the function of equalizing the current distribution of the reflective film and the heating resistor film or the heating resistor film. This has the effect of obtaining good anti-fogging properties and removing performance of water droplets and frost.

[Brief description of the drawings]

FIG. 1 is a schematic rear view of a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of FIG.

FIG. 3 is a schematic rear view of the second embodiment of the present invention.

FIG. 4 is a schematic back view of Comparative Example 3 of the present invention.

FIG. 5 is a schematic rear view of Comparative Example 4 of the present invention.

FIG. 6 is a thermographic simulated view of Example 1 of the present invention.

FIG. 7 is a thermographic simulated view of Example 2 of the present invention.

FIG. 8 is a thermographic simulated view of Example 3 of the present invention.

FIG. 9 is a thermographic simulated view of Example 4 of the present invention.

FIG. 10 is a thermographic simulated view of Example 5 of the present invention.

FIG. 11 is a thermographic simulated view of Example 6 of the present invention.

FIG. 12 is a thermographic simulated view of Example 7 of the present invention.

FIG. 13 is a thermographic photograph mimic diagram of Comparative Example 1 of the present invention.

FIG. 14 is a thermographic simulated view of Comparative Example 2 of the present invention.

FIG. 15 is a thermographic photograph mimic diagram of Comparative Example 3 of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mirror substrate 11 mirror substrate 2 reflective film and heating resistor film 12 reflective film and heating resistor film 3a power supply electrode 3b power supply electrode 13a power supply electrode 13b power supply electrode 4a lead wire 4b lead wire 5a auxiliary electrode 5b auxiliary electrode 15a auxiliary electrode 15b Auxiliary electrode 16 Thermostat 17 Thermal fuse 8 Region within average mirror temperature ± 5 ° C 8a Region within average mirror temperature ± 5 ° C 8b Region within average mirror temperature ± 5 ° C 8c Region within average mirror temperature ± 5 ° C 9 Mirror average Temperature -5 ° C or lower area 10 Mirror average temperature + 5 ° C or higher area 10a Mirror average temperature + 5 ° C or higher area 10b Mirror average temperature + 5 ° C or higher area

Claims (2)

[Claims] 1. A non-conductive mirror substrate, a reflecting film / heating resistor film or a reflecting film and a heating resistor film coated on the back surface of the substrate, and a reflecting film / heating resistor film or a heating resistor film And a sheet resistance of the reflecting film / heating resistor film or the heating resistor film disposed on the reflecting film / heating resistor film or the heating resistor film. A mirror with a heater, comprising: an auxiliary electrode having a value of 1% to 30% of a value. 2. The mirror with a heater according to claim 1, wherein the auxiliary electrode is formed such that a portion outside a region surrounded by the power supply electrode (a region not heated by the power supply electrode) is thick.