JPH10100865A - Mirror equipped with heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely operate a water eliminating/excessive heating preventing function by providing a temperature control element, at least one part thereof being in contact with a surface heating resistor film, so as to properly control a temperature of a mirror. SOLUTION: A surface heating resistor film 2 made of a nickel chromium film or the like is formed on the backside of a nearly trapezoidal glass mirror substrate 1 having a curved surface by a vacuum evaporation method, electrodes 3a and 3b made of steel paste are formed on the surface heating resistor film 2 and, by attaching a thermostat 4 as a temperature control element, a mirror equipped with a heater is made. After adhesive is applied on the specified position of the surface heating resistor film 2, the thermostat 4 is slightly inclined and pressed to the surface heating resistor film 2 and thereby a part of the end of the bottom surface of the thermostat 4 is brought into direct contact with the surface heating resistor film 2. Thus, since the temperature control element is attached to be contacted with the surface heating resistor film 2, a temperature control function is properly operated for the mirror.

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 removing water droplets, raindrops, frost, dew and ice adhering to the surface of a mirror, and is particularly suitable for a vehicle mirror.

[0002]

2. Description of the Related Art Various applications of a mirror with a heater for heating a mirror to remove water droplets, raindrops, frost, dew and ice adhering to its surface have been filed. In particular, a mirror installed outside, such as a vehicle door mirror, is liable to cause attachment of water droplets and icing during rainfall, snowfall, and the like. In such a case, there is a case where the visibility of the rear is insufficient and traveling safety is impaired, so that a reliable removal function is required.

For example, Japanese Utility Model Laid-Open Publication No. Sho 61-192963 discloses that a planar heating resistor film is formed on the entire rear surface of a glass of a rearview mirror, and the glass rear surface of the rearview mirror is energized by electrodes provided at both ends. A rearview mirror with a heater for uniformly heating is disclosed. In addition, actual Kaihei 5
Japanese Patent Publication No. 13872 proposes a mirror with a heater in which a reflecting film and a heating resistor film are formed on the mirror surface and an insulating overcoat layer is provided on the surface of the reflecting film and the heating resistor.

In these mirrors with a heater, a current is applied to the planar heating resistor film to heat the mirror surface.
The water droplets, ice, etc. attached to the mirror surface are removed by heating to obtain a good view. For this reason, the mirror with a heater is provided with a temperature control element for keeping the surface temperature of the mirror constant. As the temperature control element, an element having an opening / closing function of an energizing circuit, for example, a thermostat or a temperature fuse for suppressing a rise in a mirror temperature due to a failure of the thermostat is used. Usually, the temperature control element is attached to the mirror by fixing the temperature control element on the planar heating resistor film via an adhesive layer.

[0005]

However, as described above, the temperature control element is fixed at a position distant from the planar heating resistor film by the adhesive layer, and the distance, that is,
The thickness of the adhesive layer varies greatly, and furthermore, even if the temperature control element is slightly inclined during the fixing operation, the variation in distance increases.

A mirror with a heater provided with a temperature control element fixed at a position distant from the planar heating resistor film does not accurately transmit the temperature of the electrically heated planar heating resistor film to the temperature control element. , The function originally provided by the temperature control element does not work, causing a significant decrease in mirror temperature control performance,
The size of the distance also greatly affects the temperature control performance. For example,
When a thermostat that opens and closes at 60 ° C is used as the temperature control element, the average temperature of the mirror surface is 40 ° C to 6 ° C.
Although the temperature is desirably in the range of 0 ° C., if the thermostat is fixed at a position approximately 1 mm above the planar heating resistor film, the mirror temperature can be increased from 70 ° C. to 35 ° C.
The temperature is controlled in the range of ° C, and the water removal function of the mirror is reduced. In addition, the thermal fuse is provided to prevent overheating of the mirror due to failure of the thermostat, etc.
In view of the material and structure of the exterior case used for the vehicle mirror, the maximum temperature allowed for the mirror is up to 150 ° C., preferably 100 ° C. or less. If the film is fixed at a position approximately 1 mm above the film, the mirror temperature at the time of operation of the thermal fuse exceeds 100 ° C., and the function of preventing the mirror with heater from overheating is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mirror with a heater capable of properly controlling the temperature of the mirror, and having a function of removing moisture and a function of preventing overheating reliably.

[0008]

According to the present invention, a planar heating resistor film is formed on the back surface of a mirror substrate, and at least a pair of opposing electrodes and a temperature control element are provided on the planar heating resistor film. The mirror with a heater is characterized in that at least a part of the temperature control element is in contact with the planar heating resistor film.

FIG. 1 is a schematic rear perspective view of an embodiment of a mirror with a heater according to the present invention, and FIG. 2 is a schematic vertical sectional view of FIG. The mirror substrate 1 uses a transparent material such as glass. The cross-sectional shape may be a flat plate or a curved plate, but a vehicle rearview mirror often has a curved surface. A planar heating resistor 2 is provided on the back surface of the mirror base 1.
Are formed. This planar heating resistor 2 is made of chromium,
It is formed by forming a single layer of a resistor material such as nickel, nickel chromium alloy, titanium or the like or a metal thin film composed of multiple layers thereof by a vacuum evaporation method or a sputtering method.

Then, on the planar heating resistor 2,
At least one pair of opposing electrodes 3a, 3b for energizing this to heat the mirror with heater is formed.
Various methods can be employed for forming the electrodes 3a and 3b. For example, there is a forming method of printing an ink containing copper or silver on opposite sides of a mirror with a heater.

Further, a temperature control element is provided on the sheet heating resistor 2. At the time of installing the temperature control element, at least a part of the temperature control element is attached to the sheet heating resistor. It is necessary to attach it to the membrane. As the temperature control element, there are a type 4 having a function of opening and closing an energizing circuit, and a type 5 which cuts off the energizing circuit. Examples of the type having the opening and closing function include a thermostat and a semiconductor temperature control element.
When used for vehicles, a thermostat that has a simple structure and does not require an external operation control circuit is preferable. A type having a cutting function is a thermal fuse. The reason why at least a part of the temperature control element is attached so as to be in contact with the planar heating resistor film is to properly operate the temperature control function for the mirror. In order to mount a part of the temperature control element so as to be in contact with the sheet heating resistor film, a method of pressing the temperature control element in a state of being inclined with respect to the sheet heating resistor film at the time of attachment is adopted. In order to attach the entire surface of the temperature sensing portion of the element so as to be in contact with the planar heating resistor film, an adhesive layer is formed only on the outer peripheral portion of the temperature control element, and the temperature sensing portion and the planar heating resistor film are bonded together. In the meantime, a method of eliminating the adhesive can be adopted. In addition, the electrode 3a and each temperature control element are connected by a lead wire 6, and reference numeral 7
Is an insulating moisture-proof layer made of resin.

EXAMPLE 1 A planar heating resistor film 2 made of a nickel-chromium film having a thickness of about 40 nm was vacuum-deposited on the back surface of a substantially mirror-shaped glass mirror substrate 1 having a curved surface of 1400R. The electrodes 3a and 3b made of copper paste were formed on the planar heating resistor film 2, and a thermostat 4 having an operating temperature of 60 ° C. was attached as a temperature control element to form a mirror with a heater. When attaching the thermostat 4, 0.1 g of UV3851 (manufactured by Loctite Co., Ltd.) was used as an adhesive, applied to a predetermined position of the sheet heating resistor film 2, and then the thermostat 4 was attached to the sheet heating resistor film 2. And a part of the bottom edge of the thermostat 4 is in contact with the planar heating resistor film 2.
(See FIG. 3, reference numeral 8 is an adhesive layer).

Embodiment 2 A planar heating resistor film 2 made of a nickel-chromium film having a film thickness of about 40 nm is vacuum-deposited on the back surface of a substantially mirror-shaped glass mirror substrate 1 having a curved surface of 1400R. The electrodes 3a and 3b made of copper paste were formed on the planar heating resistor film 2, and a thermostat 4 having an operating temperature of 60 ° C. was attached as a temperature control element to form a mirror with a heater. In attaching the thermostat 4, the entire surface of the temperature sensing portion of the thermostat 4 is brought into close contact with the sheet heating resistor film 2, and then the adhesive U
V3851 (manufactured by Loctite Co., Ltd.) was applied to the outer periphery of the thermostat 4 and was fixed so that the entire periphery of the bottom of the thermostat 4 was in direct contact with the sheet heating resistor film 2 (FIG. 4).
reference).

Comparative Examples 1-4 A planar heating resistor film 2 made of a nickel-chromium film having a thickness of about 40 nm was formed on the back surface of a glass mirror substrate 1 having a curved surface of 1400R and a substantially trapezoidal shape. Electrodes 3a and 3b made of copper paste are formed on the planar heating resistor film 2 by a vacuum deposition method, and a thermostat 4 having an operating temperature of 60 ° C. is attached as a temperature control element to create a mirror with a heater. did. When attaching the thermostat 4, UV3851 (manufactured by Loctite Co., Ltd.) as an adhesive was applied to a predetermined position of the planar heating resistor film 2, and the thermostat 4 was fixed. At this time, the thicknesses of the adhesive layers are 0.5 mm, 1.0 mm, and 1.0 mm, respectively.
5, mm and 2.0 mm.

With respect to the mirrors with heaters obtained in Examples 1 and 2 and Comparative Examples 1 to 4, the temperature of the mirror surface when the circuit was opened and closed by the thermostat was measured. The surface temperature of the mirror was measured with a thermoviewer (Model JTG-5200, manufactured by JEOL Ltd.). Table 1 shows the results.

[0016]

[Table 1]

Further, the defrosting performance of the mirrors with heaters of Example 1 and Comparative Example 4 was compared.
Was 70 seconds, while Comparative Example 4 required 150 seconds. Defrosting performance test: After leaving the mirror with a heater in an environment of -30 ° C. for 15 minutes, energization was performed, and the energization time required to melt and dry frost frozen on the surface was measured.

Embodiment 3 A planar heating resistor film 2 made of a nickel-chromium film having a thickness of about 40 nm is vacuum-deposited on the back surface of a glass mirror substrate 1 having a curved surface of 1400R and a substantially trapezoidal shape. The electrodes 3a and 3b made of copper paste are formed on the planar heating resistor film 2 and a temperature fuse 5 having an operating temperature of 98 ° C. is attached as a temperature control element to form a mirror with a heater. . When attaching the thermal fuse 5, 0.05 g of UV3851 (manufactured by Loctite Co., Ltd.) was used as an adhesive, and the planar heating resistor film 2 was used.
Is applied to a predetermined position, and the thermal fuse 5 is slightly pressed with respect to the planar heating resistor film 2 so that one end of the thermal fuse 5 directly contacts the planar heating resistor film 2. (See FIG. 5).

Embodiment 4 The heater of the third embodiment is the same as the heater of the third embodiment except that the both ends of the thermal fuse 5 are in direct contact with the sheet heating resistor film 2 when the thermal fuse 5 is mounted. An attached mirror was created (see FIG. 6).

Comparative Examples 5 to 8 A planar heating resistor film 2 made of a nickel-chromium film having a film thickness of about 40 nm was formed on the back surface of a glass mirror substrate 1 having a curved surface of 1400R and a substantially trapezoidal shape. Electrodes 3a and 3b made of copper paste are formed on the planar heating resistor film 2 by a vacuum evaporation method, and a temperature fuse 5 having an operating temperature of 98 ° C. is attached as a temperature control element to mount a mirror with a heater. Created. When attaching the thermal fuse 5, 0.05 g of UV3851 (manufactured by Loctite Co., Ltd.) was used as an adhesive, and the planar heating resistor film 2 was used.
Then, the thermal fuse 5 was fixed.
The thickness of the adhesive layer at this time was 0.5 mm and 1.0 mm, respectively.
mm, 1.5, mm and 2.0 mm.

With respect to the mirrors with heaters obtained in Examples 3 and 4 and Comparative Examples 5 to 8, the temperature of the mirror surface when the circuit was cut off by a thermal fuse was measured. The surface temperature of the mirror was measured by a thermoviewer (Model JTG-5200, manufactured by JEOL Ltd.). Table 2 shows the results.

[0022]

[Table 2]

[0023]

According to the mirror with heater according to the present invention, at least a part of the thermostat and the temperature fuse as the temperature control element is installed in contact with the sheet heating resistor, so that the function of the temperature control element is excellent. It has excellent characteristics that it can operate, can appropriately control the temperature of the mirror, and the moisture removal function and the overheating prevention function work reliably.

[Brief description of the drawings]

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

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

FIG. 3 is an enlarged vertical sectional schematic view of a main part of the first embodiment.

FIG. 4 is an enlarged vertical sectional schematic view of a main part of a second embodiment.

FIG. 5 is an enlarged vertical cross-sectional schematic view of a main part of a third embodiment.

FIG. 6 is an enlarged schematic longitudinal sectional view of a main part of a fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mirror substrate 2 Planar heating resistor film 3a electrode 3b electrode 4 Thermostat 5 Thermal fuse 6 Lead wire 7 Insulation moistureproof layer 8 Adhesive layer

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroshi Hiroki 4-1-8 Yoshimachi, Soka City, Saitama Prefecture Pentel Co., Ltd.

Claims (1)

[Claims] A planar heating resistor film is formed on the back surface of the mirror substrate, and at least a pair of opposing electrodes on the planar heating resistor film, a heater-equipped mirror comprising a temperature control element,
A mirror with a heater, wherein at least a part of the temperature control element is in contact with the planar heating resistor film.