JPH0958417A - Rear view mirror for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the heat conductivity from a surface heating element to a mirror and the speed of temperature rise, enable defrosting and declouding by a uniform temperature rise on the overall surface of the mirror, facilitate the man-hour for assembly, and reduce cost. SOLUTION: A surface heating element 2 is formed directly on the rear surface of a mirror 1 by printing. Also the surface heating element 2 is formed by print-laminating an insulating film 21 as a first layer, an electrode conductive film 22 as a second layer, a heating resistance film 23 as a third layer, and a protective insulation film 24 as a fourth layer in order on the rear surface. Then the lead of a power cord 3 is soldered to the land part 22a of the electrode conductive film 22 and current is passed through it. Thus a Joule's heat is generated in the heating resistance film 23 and transferred to the mirror 1 for heating it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rearview mirror for a vehicle such as an automobile, and more particularly to a rearview mirror for a vehicle provided with a heating element on the back surface of the mirror to prevent fog.

[0002]

2. Description of the Related Art A conventional rear view mirror for a vehicle having a heating element attached to the rear surface of a mirror is shown in FIG. 20, a side view thereof is shown in FIG. 21, and a partially enlarged view thereof is shown in FIG. The mirror 1 has a reflection film 1b formed on the back surface of glass 1a, and a sheet heating element 2 is adhered to the back surface of the mirror 1. The planar heating element 2 is composed of six layers of an adhesive layer 2a, a polyester film 2b, an adhesive layer 2c, a heating resistance film 2d, an electrode conductive film 2e, and a polyester film 2f.
It is attached to the mirror 1 via a. 3 is a conductive film for electrodes 2e
It has a connector 4 at the tip, which is a cord soldered to.

[0003]

As described above, since the conventional vehicle rearview mirror is constructed by attaching the surface heating element (heater) 2 to the mirror 1, a lot of manpower is required for the work and the cost is increased. There was a drawback to Further, it was difficult to automate the attachment of the heater part. Further, structurally, since the pressure-sensitive adhesive layers 2a and 2c are interposed between the mirror 1 and the heater 2, the thermal conductivity is poor, and the temperature rise on the rear surface of the mirror takes time, resulting in poor thermal efficiency.

The object of the present invention is that the heat conductivity to the mirror is excellent, the heat efficiency is good, the temperature rise on the back surface of the mirror can be heated rapidly and uniformly, and it does not require any labor in manufacturing and is easy to automate. , The simplification of the assembly process and the reduction of cost.

[0005]

The above object is to form a heat generating circuit by directly forming an insulating film on the back surface of a mirror by printing, and laminating a conductive film for electrodes and a resistance film for heat generation on the insulating film. This is achieved by providing a planar heating element formed by covering the heating circuit with a protective insulating film.

Further, the above-mentioned object is to form an insulating film directly on the rear surface of the mirror by printing, form a heating circuit in which a conductive film for electrodes and a resistance film for heating are printed and laminated on the insulating film, and form a heating circuit on the heating circuit. This is achieved by providing a sheet heating element covered with a protective polymer foam.

Further, the above object can be achieved by using a heating circuit formed on the rear surface of the mirror, either directly or on the upper surface of which a protective insulating film is formed and covered with a heat insulating material.

The above object can be achieved by using a heat generating circuit formed on the rear surface of the mirror and a film having a good thermal conductivity between the mirror.

Further, the above object is achieved by forming a film having good thermal conductivity on the upper surface of the heat generating circuit formed on the rear surface of the mirror and using a heat insulating film on the heat conductive film. .

According to the above means, the respective films forming the sheet heating element are sequentially laminated by printing without any trouble. Further, this printed laminate film is directly formed on the back surface of the mirror without interposing an adhesive or the like, and improves the thermal conductivity to the mirror. In addition, the lowermost insulating film formed directly on the back surface of the mirror prevents the heater current flowing through the conductive film for electrodes and the resistive film for heat generation above it from leaking to the mirror side to improve heat generation efficiency, and When an insulating film having good conductivity is used, the heat generation efficiency is increased and at the same time the thermal conductivity to the mirror is increased to accelerate the temperature rise of the mirror.

Further, by covering the heat generating circuit with a heat insulating material, the heat radiation of the heater can be prevented and the heat efficiency can be further improved. When the heat generating circuit is covered with a heat insulating foam, the heat insulating property is increased and the glass Prevents scattering when damaged.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. FIG. 1 is a rear view of the mirror according to the first embodiment of the present invention, FIG. 2 is an enlarged view taken along the line BB, and FIG. 3 is an enlarged view taken along the line AA. In the figure, 1 is a mirror and 2 is a planar heating element. The mirror 1 is composed of a glass 1a and a reflective film 1b on the back surface of the glass 1a.

The planar heating element 2 is directly formed on the back surface of the mirror by printing, and has an insulating film 21 as a first layer, a conductive film 22 for electrodes as a second layer, a resistance film 23 as a heating element for a third layer, and a fourth layer. The protective insulating film 24 is sequentially printed and laminated on the layers. The first insulating film 21 has a heater current of the mirror 1
It is intended to prevent leakage to the reflection film 1b of FIG. 6 (a metal film such as Cr is used).
As shown in (A), it is uniformly printed on the heater portion on the back surface of the mirror 1. FIG. 6 shows an example of a print pattern of each layer.

The second-layer electrode conductive film 22 includes a land portion 22a for soldering a power lead wire or a terminal, a +,
The negative electrode is composed of comb-shaped portions 22b arranged alternately so as to face each other in a comb shape, and is printed with silver paste, copper paste, high-conductivity carbon ink or the like as shown in FIG. 6B.

The third heating resistance film 23 is made of carbon ink or the like having electric resistance between the comb-shaped electrodes and on the conductive film 22b for electrodes, as shown in FIG. 6C. It is formed by printing uniformly, leaving 22a. Although the heating circuit (heater) is composed of the third-layer heat-generating resistance film 23 and the second-layer electrode conductive film 22, the stacking order of the second layer and the third layer may be reversed.

The protective insulating film 24 of the fourth layer is an insulating protective overcoat for protecting the heating circuit.
6D, the surface of the heater is covered by printing, coating, pasting, spraying or the like, leaving the electrode land portion 22a, as shown in FIG. 6D.

[0017]

[Table 1]

FIG. 4 shows the appearance of the sheet heating element 2 formed by printing and laminating on the back surface of the mirror 1. The electrode conductive film 22 is exposed when printing or applying the third and fourth layers. The cord 3 is soldered and connected to the land portion 22a. An enlarged cross section of the soldering portion of the land portion 22a is shown in FIG. The core wire of the power cord 3 is soldered 51 to the electrode conductive film 22 in the land portion and covered with silicone 52 for insulation and waterproof protection.

By connecting the connector 4 at the tip of the cord 3 to a power source and supplying a heater current from the land portion 22a of the conductive film 22 for electrodes to the comb-shaped portion 22b, the resistance film 23 for heat generation interposed between the comb-shaped partial electrodes is formed. Generates heat due to Joule heat. Since the insulating film 21 is interposed between the heater current and the mirror 1, leakage to the mirror 1 is prevented, heat generation efficiency is improved, and direct printing is performed without an adhesive or the like between the heater and the mirror. Because it is a thing, the fever mirror 1
The thermal conductivity of the mirror is excellent and the temperature rise on the mirror surface can be accelerated.

By using a material having a PTC characteristic for the heating resistance film 23, it is possible to automatically control the temperature by providing a self-temperature control function.

FIG. 7 shows a second embodiment of the present invention,
FIG. 8 is a sectional view thereof. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding portions, and the first layer insulating film 21, the second layer electrode conductive film 22, and the third layer heating resistance film 23 of the planar heating element 7 are shown. Are similarly printed and laminated in sequence.

The protective film 71 of the fourth layer of this embodiment is overcoated with a polymer foam. Polyurethane, polystyrene, vinyl chloride, and other plastic materials are used for the foam, and by expanding the foam, the thermal conductivity is small and the heat insulation effect is enhanced, so heat is prevented from escaping to the back side, the thermal efficiency of the heater is increased, and the mirror Accelerate the temperature rise on the back side. Also, it is difficult to cool even after the temperature is raised. In addition, the elasticity and flexibility of the foam prevent scattering when the mirror is damaged. That is, even if the mirror is broken, the foam does not break, which is effective in preventing scattering.

There are the following methods for forming the polymer foam layer 71. After printing or applying the foamable insulating ink, heat treatment, ultraviolet irradiation, or the like according to the foaming condition of the used ink is performed to foam. In addition, a print-laminated mirror of up to three layers of the first-layer insulating film 21, the second-layer electrode conductive film 22, and the third-layer heat-generating resistance film 23 is set in a mold, and a foamed resin is formed on the surface of the laminate. Cast. Further, a method of spraying a two-liquid mixed foaming paint to form a foam on the mirror is used.

FIG. 9 shows a third embodiment of the present invention, and FIG. 10 is a sectional view thereof. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding portions, and the first layer insulating film 21 of the planar heating element 9, the second layer electrode conductive film, the third layer heating resistor film 23, Similarly, the protective insulating film 24 of the fourth layer is sequentially laminated by printing.

In this embodiment, the heat insulating material layer 9 is used as the fifth layer.
The surface of the laminate is covered with 1. As the heat insulating material, a resin foam or a substance having a structural material with a low thermal conductivity such as glass wool or rock wool is used. The coating method may be spraying, coating, integral casting, printing, pasting, or the like.

A heat insulating material 91 for covering the surface of the fifth layer laminate.
Serves to prevent the heat generated in the internal heat generating circuit from being dissipated to the outside of the rear surface of the mirror and to raise the temperature of the mirror 1 accordingly. FIG. 11 shows the temperature rise characteristics on the back surface of the mirror. Conventionally, it took more than 2 minutes for the surface temperature of the mirror to rise from the time when the switch was turned on. This is because a considerable amount of the amount of heat generated is dissipated and the thermal efficiency is low. Is. On the other hand, according to the present invention, the temperature rising characteristics are considerably improved.

Further, since the heat insulating material layer 91 prevents heat dissipation, the heat is effectively used for raising the temperature of the mirror, which brings about an energy saving effect and improves the heat retaining property, so that it is difficult to cool after raising the temperature.

The heat insulating material layer 91 has a cushioning property,
It also has the effect of preventing rattling of the mirror in the mirror housing.

In the above, the embodiment in which the first layer to the fourth layer are printed and laminated is explained. However, the heat generating resistance film 23 and the electrode conductive film 22 are reversed on the insulating film 21 of the first layer. The screen is printed and laminated, and the protective insulating film 24 of the fourth layer is laminated by a method other than printing, such as spraying, coating, integral casting, sticking, etc., and a heat insulating material 91 of a fifth layer is formed thereon. You can also Further, the fourth layer and the fifth layer can be used in common, and the heat insulating circuits from the first layer to the third layer can be covered with the insulating heat insulating layer.

Of course, the heat-generating laminate of the first to third layers or the first to fourth layers does not depend on the printing method,
It may be formed by a method of sticking a heat generating circuit in which a conductive film for electrodes and a resistance film for heat generation are laminated on an insulating sheet with an adhesive, and the upper surface of this heat generating circuit is covered with a heat insulating material 91. You can also

FIG. 12 shows a fourth embodiment of the present invention,
FIG. 13 is a sectional view thereof.

In this embodiment, a film 121 having a high thermal conductivity is used as the first layer film 121, on which a second layer electrode conductive film 22, a third layer heat generating resistance film 23, And the protective insulating film 24 of the fourth layer are sequentially printed and laminated.

The heat conductive material used for the film 121 of the first layer is a resin having epoxy resin and aliphatic polyamine as main components, for example, Three Bond 2270 (three bond Co., Ltd.) of heat conductive-liquid epoxy resin shown in Table 1. Manufactured by the company) is preferable. This is a one-component epoxy resin having excellent thermal conductivity and high insulation, which can be cured at a relatively low temperature, and has excellent adhesive strength, electrical characteristics and the like. Also,
Ceramics that have both high thermal conductivity and electrical insulation properties are being developed. Aluminum foil can be used as a material that can enhance thermal conductivity and does not have insulating properties but good thermal conductivity. A metal material such as the above, or a metal mixture material can be used.

The first layer of heat conducting film 121 is formed by printing directly on the rear surface of the mirror as in the case of the above embodiment, and the second and third layers of electrode conductive film 22 and heat generating film are formed thereon. The heating circuit of the resistance film 23 and the protective insulating film 24 of the fourth layer are sequentially printed and laminated to form the planar heating element 12.

When a voltage is applied between the + and-electrodes of the planar heating element, a voltage is applied to the comb-shaped electrodes facing each other, and a current flows through the heating resistor 23 interposed between the electrodes to generate Joule heat. In this case, normally, even if the comb-shaped electrode portion generates heat, the other portions hardly generate heat, but since the film 121 having good thermal conductivity is formed, the heat-conducting film 121 is also applied to the portion that does not generate heat.
The heat is conducted through and the heat spreads over the entire surface and is uniformly heated.
As a result, the uniform defrosting and dewizing effects on the entire surface of the mirror 1 can be obtained. Further, the conductivity of heat generation to the mirror 1 is enhanced and the temperature rise characteristic is excellent, and it is possible to defrost and defrost in a short time.

Conventionally, in the absence of the heat conducting film 121, it takes time until the mirror temperature rises after energization, the heat radiation to the back surface increases, and the thermal efficiency becomes poor.
Although the defrosting effect was not uniform on the entire surface and a comb-shaped pattern pattern of the circuit appeared in some cases, such a defect can be eliminated.

The heat conductive film 121 is formed on the rear surface of the mirror 1 by attaching an aluminum foil of a heat conductive material, a heat conductive resin, or the like,
It can be formed by coating, vapor deposition, or any other method. In addition, the formation of the heat generating circuit on the heat conducting film 121 is performed with reference to FIGS.
In addition to printing, a method of sticking a heat generating circuit laminated on an insulating sheet with an adhesive as shown in FIG. Further, the outermost overcoat of the planar heating element can also be sprayed, applied, integrally molded, or attached.

FIG. 16 shows a fifth embodiment of the present invention,
FIG. 17 is a sectional view thereof. First insulating film 21, second
As in the case of FIG. 1, the layer electrode conductive film 22 and the third layer heat generating resistance film 23 are sequentially printed and laminated on the rear surface of the mirror to form a heat generating circuit.

In this embodiment, a film 161 having good thermal conductivity is formed as a fourth layer on the laminated heating element, and a heat insulating layer 162 is formed thereon as a fifth layer. 4th
By forming the heat conductive film 161 in the layer, the heat generation state when heat is generated by Joule heat in the heat generating resistance film 23 by applying a voltage between the + and − electrodes can be made uniform by the heat conduction of the heat conductive film 161. it can. In addition, a heat insulating layer 1 is formed on the outer surface.
By forming 62, it is possible to prevent heat dissipation and improve thermal efficiency.

The heat conductive film 161 is made of the heat conductive material used for the film of the first layer of the fourth embodiment.
The heat insulating material used for the fifth layer of the third embodiment can be used for 62.

18 and 19 show another embodiment,
An example in which a planar heating element 18 having a heating circuit formed by laminating a conductive film for electrodes and a resistive film for heating on an insulating sheet is attached to the rear surface of a mirror, and a heat conducting film 161 and a heat insulating layer 162 are formed thereon. Therefore, the same effect as the fifth embodiment can be obtained.

[0042]

As described above, according to the present invention, the insulating film is directly formed on the back surface of the mirror by printing, and the heating circuit is printed and laminated thereon, so that the leakage of the heater current is prevented and the heating efficiency is improved. , The heat conduction from the heating element to the mirror is excellent and the temperature rise is accelerated. Further, by using a foam or other heat insulating material for the surface protection film of the heat generating circuit, the heat radiation to the outside is suppressed, the heat efficiency is improved, and the temperature rise on the rear surface of the mirror is increased. Further, since the film having good thermal conductivity is interposed between the mirror and the heat generating circuit, the spread of heat generation is good and uniform heat transfer and temperature rise can be performed. Even if this is formed on the upper surface of the heating circuit, the same rapid and uniform defrosting and defrosting effect can be obtained.

Further, according to the present invention, since the sheet heating element is printed on the mirror, the assembling process can be simplified and automated, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a structural view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is an external view of an embodiment of the present invention.

5 is a partially enlarged sectional view of FIG.

FIG. 6 is a print pattern diagram of an embodiment of the present invention.

FIG. 7 is a structural diagram of another embodiment of the present invention.

FIG. 8 is a sectional view of FIG.

FIG. 9 is a structural diagram of another embodiment of the present invention.

FIG. 10 is a sectional view of FIG. 9;

FIG. 11 is a mirror temperature rising characteristic diagram of the present invention.

FIG. 12 is a structural diagram of another embodiment of the present invention.

FIG. 13 is a sectional view of FIG. 12;

FIG. 14 is a structural diagram of another embodiment of the present invention.

FIG. 15 is a sectional view of FIG. 14;

FIG. 16 is a structural diagram of another embodiment of the present invention.

FIG. 17 is a sectional view of FIG.

FIG. 18 is a structural diagram of another embodiment of the present invention.

FIG. 19 is a sectional view of FIG.

FIG. 20 is a structural diagram of a conventional example.

FIG. 21 is a sectional view of FIG. 20.

FIG. 22 is a partially enlarged view of FIG. 21.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mirror, 2 ... Sheet heating element, 21 ... Insulating film, 22 ... Electrode conductive film, 23 ... Heating resistive film, 24 ... Protective insulating film, 3 ... Cord, 4 ... Connector, 7 ... Sheet heating Body, 71
... Foam material layer, 9 ... Sheet heating element, 91 ... Insulating material layer, 12 ...
Sheet heating element, 121 ... Heat conductive film, 14 ... Sheet heating element, 1
6 ... Sheet heating element, 161 ... Heat conductive film, 162 ... Heat insulating material layer, 18 ... Sheet heating element.

Claims (5)

[Claims] 1. A rear-view mirror for a vehicle, wherein a planar heating element is provided on the rear surface of the mirror, and an insulating film directly printed on the rear surface of the mirror.
For a vehicle characterized in that a planar heating element including a heating circuit in which a conductive film for electrodes and a heating resistance film are printed and laminated on the insulating film and a protective insulating film covering the heating circuit are provided. Rearview mirror. 2. A rear-view mirror for a vehicle, wherein a planar heating element is provided on the rear surface of the mirror, and an insulating film printed directly on the rear surface of the mirror.
A planar heating element comprising a heating circuit in which a conductive film for electrodes and a heating resistive film are printed and laminated on the insulating film, and a protective polymer foam covering the heating circuit is provided. Rear-view mirror for vehicles. 3. A heat generating circuit in which a conductive film for electrodes and a resistance film for heat generation are laminated on an insulating sheet is attached to the back surface of the mirror, or a conductive film for electrodes and a resistance film for heat generation are directly printed and laminated to generate heat. A vehicle rear-view mirror having a circuit, wherein a heat insulating material is provided directly on the upper surface of the heating circuit or on a protective insulating film formed thereon. 4. A heat generating circuit in which a conductive film for electrodes and a resistance film for heat generation are laminated and formed on an insulating sheet is attached to the back surface of the mirror, or a conductive film for electrodes and a resistance film for heat generation are directly printed and laminated to generate heat. A rear view mirror for a vehicle having a circuit, wherein a film having good thermal conductivity is interposed between the heat generating circuit and the mirror. 5. A heat generating circuit in which a conductive film for electrodes and a resistance film for heat generation are laminated and formed on an insulating sheet is attached to the back surface of the mirror, or a conductive film for electrodes and a resistance film for heat generation are directly printed and laminated to generate heat. A rear-view mirror for a vehicle having a circuit, wherein a film having good thermal conductivity is provided on an upper surface of the heat generating circuit, and a heat insulating material is provided on the heat-conductive film.