JP2001213284A - Mirror having heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror having a heater of a structure which requires no thermostat or thermistor as a temperature control component and is as simple as possible. SOLUTION: The mirror having the heater comprises a non-conductive mirror substrate, a heat-generating resistor film which is also used as a reflective film or a reflective film and the heat-generating resistor film which is covered on a back surface of the substrate, a sheet heating body which is disposed on the heat-generating resistor film which is also used as the reflective film or the heat-generating resistor film and has the self-temperature adjusting function, and at least a pair of power supply electrodes disposed so as to simultaneously supply the power to the heat-generating resistor film which is also used as the reflective film or the heat-generating resistor film and the sheet heating body.

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. . Particularly, in this type of mirror, it is known that a current is applied to a reflective film provided on the back surface of the mirror to generate heat, thereby heating the mirror to obtain an anti-fog effect. In this mirror, thermostats, thermistors,
It is common to use components such as thermal fuses, but a sheet-like heating element with a self-temperature control function is formed from a material having PTC characteristics, and this is attached to a mirror and connected in series with a reflection film as a heating resistor. Japanese Patent Application Laid-Open No. 10-329660 discloses a mirror for controlling the temperature by controlling the energization due to a rise in resistance caused by a rise in temperature.

[0003]

However, when a thermostat or thermistor is used as a temperature control component,
There is a problem that the cost increases. Also,
When a reflection film as a heating resistor and a planar heating element having a self-temperature control function are connected in series, there is a problem that the structure becomes complicated such that a large number of power supply electrodes for conducting electricity are required. .

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and comprises a non-conductive mirror substrate, a reflective film and a heating resistor coated on the back surface of the substrate. A film or a reflective film and a heating resistor film; a sheet heating element having a self-temperature adjusting function disposed on the reflective film and the heating resistor film or the heating resistor film; and the reflecting film and the heating resistor film Alternatively, there is provided a mirror with a heater, comprising: a heating resistor film and at least one pair of power supply electrodes arranged so as to be capable of supplying power to the planar heating element at the same time.

[0005]

In the mirror with heater according to the present invention, when the energization is started, both the reflection film and the heating resistor film and the planar heating element having a self-temperature adjusting function are energized, and heat is generated to quickly raise the temperature of the mirror. As a result, the resistance value of the planar heating element having a self-temperature adjustment function increases, so that the amount of electricity is reduced, the heat generation is suppressed, and the heating becomes dull. Keeps a constant temperature. Due to its structure, temperature control parts such as thermostats are not required.
Since the reflection film / heating resistor film and the planar heating element having a self-temperature adjusting function are connected in parallel, the power supply electrode can be shared.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic rear view of a mirror with a heater used for an automobile rearview mirror, and FIG. 2 is a schematic cross-sectional view thereof.
The non-conductive mirror substrate 1 is formed of a transparent material such as glass or an acrylic plate. Regardless of the present embodiment, an arbitrary shape can be selected for the outer shape and cross section according to the design and visibility of the vehicle to be mounted.

On the back surface of the mirror substrate 1, there is formed a reflective film / heat generating resistor film 2 made of titanium as a metal thin film by a sputtering method. This reflection film and heat generating resistor film 2
Is chromium, nickel-chromium alloy, aluminum
A metal thin film such as a titanium-based alloy may be formed by a sputtering method or a vacuum evaporation method, and a first film having a function as a reflection film and a second film having a function as a heating resistor film are formed. A configuration other than a single layer such as a two-layer structure may be adopted. In the case of a two-layer structure, the first layer is made of aluminum, chromium, nickel, a nickel-chromium alloy,
A metal thin film such as nickel-phosphorus is formed by a sputtering method, a vacuum evaporation method, a plating method, or the like, and the second layer is formed of titanium, titanium silicide, chromium silicide, tantalum nitride, titanium carbide, tungsten carbide, niobium boride,
A metal thin film such as an iron-chromium-aluminum alloy 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, a metal thin film of aluminum, chromium, nickel, nickel-chromium alloy, nickel-phosphorus, or the like is formed as a reflective film by a sputtering method, a vacuum evaporation method, a plating method, or the like. It is formed by a sputtering method or a vacuum deposition method, and as a heating resistor film, a metal thin film of titanium, titanium silicide, chromium silicide, tantalum nitride, titanium carbide, tungsten carbide, niobium boride, iron-chromium-aluminum alloy, etc. is sputtered. It can be formed by a method, a vacuum evaporation method, a plating method, or the like.

[0008] At least a pair of power supply electrodes 3a and 3b are formed on the reflective film / heat generating resistor film 2 for energizing the film to generate heat. This feeding electrode 3
a and 3b are formed by printing a silver paste, a copper paste, or the like on the reflective film and the heating resistor film 2;
It can be formed by various methods such as forming a thin film of metal such as copper or nickel directly by sputtering or plating.

Further, on the reflection film / heating resistor film 2,
A planar heating element 4 having a self-temperature adjusting function is formed so as to be connected to the aforementioned power supply electrodes 3a and 3b. This planar heating element 4 is made of a thermoplastic resin having a certain coefficient of thermal expansion, in which conductive particles such as carbon, copper, and silver are dispersed.
Although it is composed of a material having TC characteristics, various methods can be used for forming the material, such as screen-printing the material into a paste or applying a paint.

The shape of the planar heating element 4 need not be an integral planar shape as in this embodiment. Various shapes such as a slit shape can be selected according to a desired temperature distribution and a mirror shape as long as the power supply electrode is arranged so as to be capable of supplying power simultaneously with the reflection film and the heating resistor film.

The resistance value of the sheet heating element 4 can be arbitrarily set in accordance with a desired mirror temperature. However, when the energization is started, heat is generated by energizing both the reflection film / heating resistor film 2 and the sheet heating element 4. In order for the mirror to satisfy the functions of reducing heat generation due to a decrease in the amount of current supplied to the planar heating element 4 as the temperature rises, and finally generating heat by energizing substantially only the reflection film and the heating resistor film, a desired mirror temperature is required. Before and after, it is desirable that the resistance value is changed from a lower resistance value to a higher resistance value than the resistance value of the reflection film / heating resistor film 2.

Further, in this embodiment, the reflection film / heating resistor film 2 and the sheet heating element 4 are in contact with each other, but the difference in resistance between the reflection film / heating resistor film 2 and the sheet heating element 4 is very small. In the case of being large, the reflecting film / heating resistor film 2 and the sheet heating element 4 between the feeding electrodes 3a and 3b forming a pair form the sheet heating element 4 or the sheet heating element 4 from the reflecting film / heating resistor film 2. There is a case where a large current flows from the body 4 toward the reflection film and the heating resistor film 2 and a biased temperature distribution is formed. For the purpose of preventing this, an insulating sheet or the like may be provided between the reflecting film / heating resistor film 2 and the sheet heating element 4 to insulate both.

A power supply electrode (not shown) is provided on the power supply electrode 3a.
Lead wires 5 and 6 are connected by soldering or the like for energization.

The insulating and moisture-proof layer 7 is used for the purpose of improving corrosion resistance, and is formed by coating an insulating and moisture-proof coating material in which an insulating and moisture-proof material is dissolved in an organic solvent.

[0015]

According to the mirror with heater according to the present invention, the reflection film / heating resistor film and the planar heating element having the self-temperature control function are connected in parallel, so that the temperature control parts are eliminated and the cost can be reduced. In addition, even in the case where a reflection film / heating resistor film and a planar heating element having a self-temperature control function are connected in series, there is an excellent effect that the structure can be simplified, for example, the power supply electrode can be shared. is there.

[Brief description of the drawings]

FIG. 1 is a schematic rear view of a mirror with a heater according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a mirror with a heater according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mirror substrate 2 Reflection film and heating resistor film 3a Power supply electrode 3b Power supply electrode 4 Planar heating element 5 Lead wire 6 Lead wire 7 Insulation moistureproof layer

Claims (3)

[Claims] 1. A non-conductive mirror substrate, a reflection film / heating resistor film or a reflection film and a heating resistor film coated on the back surface of the substrate, and the reflection film / heating resistor film or the heating resistor film A sheet heating element having a self-temperature adjusting function disposed thereon, and at least one pair of a reflection film and a heating resistor film or at least one pair arranged so as to be capable of supplying power to the sheet heating element at the same time. A mirror with a heater, comprising a power supply electrode. 2. A resistance value of a sheet heating element having a self-temperature adjusting function is lower than a resistance value of a reflection film / heating resistor film or a heating resistor film before and after a desired mirror temperature obtained by energization. The mirror with a heater according to claim 1, wherein the mirror changes from a high value to a high value. 3. The heating element having a self-temperature adjusting function, wherein the sheet heating element is formed on the reflection / heating resistor film or the heating resistor film in direct contact therewith. Mirror with heater.