JPH07257328A - Mirror with heater - Google Patents

Abstract

PURPOSE:To quickly eliminate the water drops on the surface of a mirror in a mirror with a heater, which is provided with an electrode for electrifying to heat a heating resistor, by setting the maximum voltage lowering quantity inside of an electrode in relation to the feeding point of the electrode at predetermined % of the feeding voltage. CONSTITUTION:A pair of opposite electrodes 3a, 3b for electrifying a heating resistor working as a reflecting film 2 are provided in the back surface of the heating resistor working as a reflecting film 2, and these electrodes 3a, 3b are provided in the condition that a space between the electrodes 3a, 3b is formed narrower near the right and left ends of a mirror board 1 than the space at a central part thereof so that the right and the left ends of a mirror can be heated. In the electrodes 3a, 3b, voltage is lower, as the distance from feeding points A1, A2 is farther. Consequently, the ends E1, E2 of the electrode 3a are the maximum voltage lowering point inside of the electrode 3a, and the ends E3, E4 of the electrode 3b are the local maximum voltage lowering point. In this mirror with a heater, maximum voltage lowering quantity among the local maximum voltage lowering points inside of the electrode is set at 0.5-20% of the feeding voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for use in bathroom mirrors, vehicle door mirrors, etc., and is equipped with a heater for anti-fogging or removing water drops, raindrops, dew, ice, etc. adhering to the mirror surface. Regarding the mirror.

[0002]

2. Description of the Related Art Various mirrors that can be heated have been proposed. Such a mirror that can be heated can be visually recognized by mirrors used in bathrooms and washrooms where water droplets adhere to the surface and are easily fogged, or when raindrops or raindrops cause raindrops, snow powder adhesion, or freezing during cold weather. It is often used as a mirror for vehicles that tend to deteriorate in water resistance.
The purpose is to remove dew and ice by heating the mirror.

For example, Japanese Utility Model Publication No. 58-28937 discloses a vehicle back in which a soaking plate having a high thermal conductivity is arranged in close contact with the back face of a mirror plate, and a heating element is joined to the back face of the soaking plate. A mirror is disclosed. In addition, 62-33
Japanese Patent No. 648 discloses a mirror with a heater in which a flat heater is fixed to the back surface of the mirror body and the heater pattern is closer to the peripheral portion of the mirror than the central portion. Further, Japanese Utility Model Publication No. 4-102599 discloses a planar heating element for a mirror in which a heating area is divided into a plurality of areas by electrodes.

In the above-mentioned mirror or planar heating element for a mirror, in order to uniformly heat the entire surface of the mirror so as to obtain a good field of view, an electric heating substrate having a complicated heating resistor pattern or a complicated electrode pattern is formed. Was formed and the electrothermal substrate was fixed to the rear surface of the mirror substrate. However, in the method of fixing the mirror substrate and the separate electric heating substrate to each other, complicated heating resistor patterns and electrode patterns have to be designed and manufactured, which causes a problem of high cost. In addition, since the mirror substrate is heated by heat conduction from a separate electric heating substrate, the thermal efficiency is poor,
There is also a problem that it takes a long time to remove water drops and the like.

Therefore, as in Japanese Utility Model Application Laid-Open No. 5-13872, a reflecting film / heating resistor is formed on the surface of the mirror substrate, and an insulating overcoat layer is provided on the surface of the reflecting film / heating resistor. Heater mirrors have been proposed.

[0006]

However, when the reflecting film / heating resistor is formed on the surface of the mirror substrate, the thermal efficiency is improved, but there is a problem in durability and cost of the insulating overcoat layer. . In addition, a mirror having a reflecting film and a heating resistor formed on the surface of the mirror substrate has a problem that it is easy to heat only the central portion of the mirror and it takes a long time to remove water droplets and the like at the end portion and particularly at the electrode portion. It was. In order to solve this problem, in order to quickly remove water droplets or the like from the ends or electrodes, a large amount of power must be supplied,
Not only is it inefficient, but overheating of the central part also causes disasters such as burning and deformation of peripheral parts and burns due to human contact.

An object of the present invention is to provide at low cost a mirror with a heater capable of quickly removing water droplets and the like on the mirror surface by uniformly heating the entire surface of the mirror substrate including the electrode portion with good thermal efficiency.

[0008]

The present invention has been made to solve the above-mentioned conventional problems, and forms a reflecting film / heating resistor film or a reflecting film and a heating resistor film on a substrate. Along with this, in the heater-equipped mirror having an electrode for heating the heating resistor with electricity, the maximum amount of voltage drop in the electrode with respect to the feeding point of the electrode is 0.5 to 2 of the feeding voltage.
The gist is a mirror with a heater characterized by 0%.

FIG. 1 is a schematic rear perspective view of a heater-equipped mirror used in a vehicle door mirror according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional schematic diagram thereof. Reference numeral 1 is a mirror substrate, which is made of a transparent material such as glass. A reflective film / heating resistor film 2 is formed on the rear surface of the mirror substrate 1. The reflective film / heat generating resistor film 2 is formed of a film of titanium, chromium, nichrome 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 case where the film formed on the rear surface of the mirror substrate 1 also serves as the reflective film and the heat generating resistor film as in the present embodiment. . For example, a multi-layered film is formed, and each film has a function as a reflection film and a function as a heating resistor film, or an insulating layer is formed between the reflective film and the heating resistor film. However, those formed so as not to be electrically connected can also be used. When forming a multilayer film,
The first layer is made of aluminum, chromium, nickel, nichrome alloy, nickel-phosphorus or the like as a material and is formed by a sputtering method, a vacuum deposition method or a plating method, and the second layer is made of titanium, titanium silicide,
It can be formed by a sputtering method, a vacuum deposition method, a plating method, or the like using chromium silicide, tantalum nitride, titanium carbide, tungsten carbide, niobium boride, an iron-chromium-aluminum alloy, or the like. When the reflective film and the heating resistor film are separately formed, aluminum, chromium, nickel, nichrome alloy, nickel-phosphorus, or the like is used as the material for the reflective film, and the sputtering method, the vacuum deposition method, the plating method, or the like is used. Silica is used as the insulating layer and titanium, titanium silicide, chromium silicide, tantalum nitride, titanium carbide, tungsten carbide, niobium boride, iron-chromium-aluminum alloy, etc. are used as the material for the heating resistor film. It can be formed by a sputtering method, a vacuum deposition method, a plating method, or the like.

A pair of opposing electrodes 3a, 3b for energizing the heating resistor / reflection film 2 are provided on the back surface of the heating resistor / reflection film 2. The electrodes 3a and 3b facing each other have a space between the electrodes 3a and 3b near the left and right ends of the mirror substrate 1 so that the electrodes can be heated at the left and right ends (direction of FIG. 1) of the mirror. It is provided to be narrower than the interval.

The electrodes 3a and 3b can be formed by various methods. For example, a thin layer of copper or silver is formed using a copper paste or a silver paste, solder is applied on the thin layer, or a thin layer of nickel is formed by nickel plating. Normally, electrodes are formed with a uniform thickness and a uniform width, but by making the thickness and width of the electrodes non-uniform, changing the resistance value of the electrodes depending on the location, or connecting electrodes made of multiple materials, It is also possible to change the rate of the voltage drop within. Further, the number of electrodes is not limited to two. For example, although not shown, a new electrode is provided in the middle of the electrodes 3a and 3b in FIG. Such an electrode may be used as the negative electrode, or as another example, a pair of electrodes may be additionally provided on the left and right ends of the substrate in FIG.

Further, the back surface of the heat generating resistor / reflection film 2 and the back surfaces of the electrodes 3a and 3b are coated with an insulating material 4 such as resin / rubber having a low Young's modulus which does not cause cracks due to temperature change, for electrical insulation. Has been done.

Reference numeral 5 is a lead wire for connecting the electrodes 3a, 3b to a power supply circuit (not shown). The lead wire 5 is connected to the electrodes 3a, 3b by soldering or the like. A connection point A ₁ between the lead wire 5 and the electrode 3a is a feeding point of the electrode 3a, and a connection point A ₂ between the lead wire 5 and the electrode 3b is a feeding point of the electrode 3b.

In the electrodes 3a, 3b, the feeding points A ₁ ,
The voltage drops as the distance from A ₂ increases. Therefore, the ends E ₁ and E ₂ of the electrode 3a are the maximum voltage drop points in the electrode, and the ends E ₃ and E _{4 of} the electrode 3b are also the maximum voltage drop points in the electrode. In the mirror with a heater of the present invention,
At the maximum voltage drop point in the electrode, the maximum voltage drop amount needs to be 0.5 to 20% of the power supply voltage. When the maximum voltage drop is less than 0.5% of the power supply voltage, the amount of heat generated by the electrodes is too small to uniformly heat the entire surface of the mirror substrate including the electrode portions. Further, when the maximum voltage drop exceeds 20% of the power supply voltage, a large amount of power needs to be supplied to heat the entire mirror, resulting in poor efficiency.

There may be a plurality of feeding points in the electrode. FIG. 3 is a schematic rear perspective view of a heater-equipped mirror used in a vehicle door mirror that is another embodiment of the present invention. This embodiment is the same as the above embodiment except that two feeding points are formed for one electrode in the above embodiment. In this embodiment, the feed points for the electrode 3a are A ₁ and A ₃ , and the maximum voltage drop points in the electrode 3a are E ₁ , E ₂ and the feed points A ₁ and A ₃ which are the ends of the electrode 3a. It is E ₅ , which is the potential midpoint of Also, the electrode 3
The feeding points for b are A ₂ and A ₄ , and the maximum voltage drop points in the electrode 3b are E ₃ , E ₄ at the ends of the electrode 3b and the potential intermediate point between the feeding points A ₂ and A _4. A certain E ₆ .

[0016]

With the heater-equipped mirror of the present invention, the entire surface of the mirror including the surface provided with the electrodes can be uniformly heated under the desired temperature control. This is because it is possible to efficiently heat the entire mirror by heating the mirror substrate to be heated and adjusting the power consumption of the electrode portion to an appropriate amount.

[0017]

EXAMPLES The present invention will be described in more detail below with reference to examples.Examples 1-5 and Comparative Examples 1, 2  For the mirror with heater having the structure shown in FIG. 1 and FIG.
On the glass mirror substrate as shown in Table 1
The sprayed film is formed by the sputtering method, and the metal
Stroke screen printing method is used to form thin metal layers as electrodes.
Power supply point A₁-A₂ Apply a voltage of DC12V between
It was

[0018]

[Table 1] Note) Supplementary explanation of Table 1 Electrode of Example 2: formed thicker than that of Example 1. Electrode of Example 4: formed thicker than that of Example 3. Heat generating resistor / reflection film of Example 5: A titanium film was formed on the nichrome film. Electrode of Comparative Example 2: A thick solder film was formed on the copper thin layer.

Example 6 With respect to the mirror with heater having the structure shown in FIG. 3, a chromium layer of 0.02 μm was formed on a glass mirror substrate by a sputtering method, and 0.03 μm was formed on this chromium layer.
The titanium layer is formed by a sputtering method as a heat resistor / reflection film, and a silver thin layer is formed on this heat resistor / reflection film by a screen printing method of silver paste. A thin copper layer is formed and used as an electrode, feeding points A ₁ , A
A voltage of DC 12V was applied between ₃ and A ₂ and A ₄ .
At this time, the current between the electrodes was 4.5A.

The voltage drop at the maximum voltage drop point of the mirror with heater obtained in Examples 1 to 6 and Comparative Examples 1 and 2 was measured. The results are shown in Table 2.

[0021]

[Table 2]

The temperature of the mirror surface was measured by controlling the heating of the mirror with heater obtained in Examples 1 to 6 and Comparative Examples 1 and 2 by a thermostat.

Example 1 Although the temperature in the vicinity of the feeding point was slightly higher, the temperature of the mirror surface including the portion corresponding to the electrode portion could be controlled as set within the range of 45 to 65 ° C.

Example 2 The temperature of the mirror surface including the portion corresponding to the electrode portion was set to 5
It was possible to control as set in the range of 0 to 60 ° C.

Example 3 The temperature of the mirror surface including the portion corresponding to the electrode portion was set to 5
It was possible to control as set in the range of 0 to 60 ° C.

Example 4 The temperature of the mirror surface including the portion corresponding to the electrode portion was set to 5
It was possible to control as set in the range of 0 to 60 ° C.

Example 5 Although the temperature rise at the end portions of the electrodes, particularly near E ₁ and E ₄ is slightly large, the temperature of the mirror surface including the portions corresponding to the electrode portions is set within the range of 50 to 65 ° C. as set. I was able to control it. Although the voltage drop of A ₁ -E ₂ and A ₂ -E ₃ was 0.5% or less of the power supply voltage, the distance of A ₁ -E ₂ and A ₂ -E ₃ was short, so A ₁ -E ₂ , A ₂ -E ₃ part was also uniformly heated.

Example 6 Although the temperature rise at the end portions of the electrodes, particularly near E ₁ and E ₄ is slightly large, the temperature of the mirror surface including the portion corresponding to the electrode portions is set within the range of 50 to 65 ° C. as set. I was able to control it. . Although the voltage drop of A ₁ -E ₂ and A ₂ -E ₃ was 0.5% or less of the power supply voltage, the distance of A ₁ -E ₂ and A ₂ -E ₃ was short, so A ₁ -E ₂ , A ₂ -E ₃ part was also uniformly heated.

Comparative Example 1 The temperature in the vicinity of the feeding point was significantly higher than the temperature in the vicinity of the electrode end, and the temperature on the mirror surface was 35 to 85 ° C., and it was not possible to control within the set temperature range.

Comparative Example 2 The portion corresponding to the electrode was not heated, and the electrode end portion, especially E
₁ , because an abnormally high temperature part was locally generated near E ₄ , the temperature of the mirror surface was 40 to 95 ° C., and it was not possible to control within the set temperature range.

[0031]

The heater-equipped mirror according to the present invention consumes an appropriate amount of electric power even in the electrode portion, so that uniform heating can be obtained over the entire surface of the mirror substrate including the electrode portion, so that desired temperature control is possible. Thus, water drops, ice, etc. adhering to the mirror surface can be quickly removed over the entire surface.

[Brief description of drawings]

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

FIG. 2 is a schematic vertical sectional view of FIG.

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Mirror substrate 2 Heat-generating resistor / reflection film 3a, 3b Electrode 4 Insulation material 5 Lead wires A ₁ , A ₂ , A ₃ , A ₄ Feed points E ₁ , E ₂ , E ₃ , E ₄ , E ₅ on electrodes , E ₆ electrode maximum voltage drop point

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 1, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017]

EXAMPLES The present invention will be described in more detail below with reference to examples. Per Heated mirrors having the configuration shown in Examples 1 to 5 and Comparative Examples 1 and 2 Figures 1 and 2, the heat generation resistor and the reflective film as in Table 1 was formed by sputtering on a glass mirror substrate Further, a thin metal layer was formed as an electrode by a screen printing method of a metal paste, and a voltage of DC 12V was applied between the feeding points A _{1 and} A ₂ .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

Example 6 With respect to the mirror with heater having the structure shown in FIG. 3, a chromium layer of 0.02 μm was formed on a glass mirror substrate by a sputtering method, and 0.03 μm was formed on this chromium layer.
Titanium layer was formed by a sputtering method fever resistive and reflective films and none, to form a silver thin layer by screen printing of silver paste on the heat generation resistor and the reflective film, the silver thin layer A thin copper layer was formed on it to form an electrode, and a voltage of DC 12 V was applied between the feeding points A ₁ , A ₃ and A ₂ , A ₄ . At this time, the current between the electrodes was 4.5A.

Claims (1)

[Claims] 1. A mirror with a heater, wherein a reflective film and a heating resistor film, or a reflective film and a heating resistor film are formed on a substrate, and an electrode for heating and heating the heating resistor is provided. A mirror with a heater, wherein the maximum voltage drop in the electrode with respect to the feeding point of the electrode is 0.5 to 20% of the feeding voltage.