JPH0725095Y2 - Anti-fog mirror - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-fog mirror suitable for use in humid rooms such as bathrooms and washrooms.

[0002]

2. Description of the Related Art Mirrors used in bathrooms and washrooms are protected against fog by applying a film having an antifog effect on the surface or coating a paint having an antifog effect on the surface. . However, these films and paints tend to peel off due to humidity and temperature changes, and even after being used for a while, the anti-fog function deteriorates.

Therefore, there has been considered an anti-fog mirror in which a heater is attached to the back surface of the mirror and the surface of the mirror is heated by heat conduction to prevent fog. For the heater, for example, a film-shaped heating element having a surface of a heat resistant polymer film coated with carbon, metal or the like can be used.

[0004]

However, in the above conventional anti-fog mirror, a temperature control circuit is required to keep the heat generation temperature of the heater at a predetermined temperature, and from the viewpoint of safety, it is necessary to prevent overheating. A circuit for this is also required. Therefore, there is a problem that the number of parts increases and the manufacturing cost increases.

Therefore, in Japanese Utility Model Laid-Open No. 48-65497, a positive temperature characteristic thermistor having a self-controlling characteristic of heat generation temperature is used as a heater, and the thermistor is embedded in the rear surface of the mirror to reduce the number of parts. An antifog mirror adapted to be reduced is disclosed.

However, also in this anti-fog mirror, if an air layer is formed between the mirror and the positive temperature characteristic thermistor, it becomes difficult for heat to conduct to the mirror, so that the surface temperature of the mirror is hard to rise and it becomes cloudy. It brings a new problem that it is difficult to exert the stopping effect.

[0007]

[Means for Solving the Problems] The anti-fog mirror according to the present invention comprises:
In order to solve the above-mentioned problems, a heat generating element made of a positive temperature coefficient thermistor is arranged on a first metal plate fixed to the back surface of a mirror, and a second metal plate is provided on the heat generating element. In the mirror, an electrically insulating liquid is filled between the first and second metal plates so as to surround the heating element, and the peripheries of the first and second metal plates are sealed to prevent the liquid from leaking. It is characterized by

[0008]

With the above structure, the first member fixed to the back surface of the mirror
In the anti-fog mirror in which a heating element made of a positive temperature coefficient thermistor is arranged on the metal plate, and a second metal plate is provided on the heating element,
An electrically insulating liquid is filled between the first and second metal plates so as to surround the heating element, and the peripheries of the first and second metal plates are sealed to prevent the liquid from leaking.
When a voltage is applied between the first and second metal plates, a current flows through the heating element to generate heat. At this time, the liquid is heated to a constant temperature by the self-temperature control function of the positive temperature characteristic thermistor, and the mirror is efficiently heated through the first metal plate. Thereby, a high anti-fog effect can be obtained. Moreover, the first
Since dew condensation of water vapor does not occur between the second metal plate and the second metal plate, a short circuit of the heating element can be prevented, and a highly reliable anti-fog mirror can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

As shown in FIG. 1, the antifog mirror of this embodiment is
Metal plate 2 (first metal plate) attached to the back surface of mirror 1.
, A PTC heating element 3a, which is a disc-shaped positive temperature characteristic thermistor disposed on the metal plate 2, and a PTC heating element 3
a ... Metal plate 4 (second metal plate) provided on the top and electrically insulating heat insulating material 5 formed so as to cover the metal plate 4.
have. Lead wires 7 are provided on the metal plates 2 and 4, respectively.
・ 7 is soldered.

An electrically insulating liquid 3b is filled between the metal plates 2 and 4 so that the heat generated by the PTC heating elements 3a ... Can be uniformly transferred to the metal plates 2 and 4. A space between the periphery of the heat insulating material 5 and the mirror 1 is sealed with a seal material 6 for preventing leakage of the liquid 3b, waterproofing, and electrical insulation.

A material having high electrical conductivity and thermal conductivity is used for the metal plates 2 and 4, and specifically, for example, a copper plate is used. As shown in FIG. 3, the metal plate 2 has an elliptical shape, and is placed at the position where the face of the mirror 1 is exactly reflected by a silicone adhesive or a urethane adhesive.
It is pasted.

The material for the PTC heating elements 3a ...
A barium titanate-based porcelain semiconductor is used. As shown in FIG. 2, the PTC heating elements 3a ...
It is placed between 4 and the metal plate 2.4 by cream solder.
Is soldered to. Silicon oil, for example, is used as the liquid 3b.

The liquid 3b is injected as follows. That is, after sealing with the sealing material 6 except a part of the periphery of the metal plates 2 and 4, the liquid 3b is injected using the unsealed portion as an injection hole. After the injection, the injection hole is closed with the sealing material 6.

A heat resistant resin is used for the heat insulating material 5, for example, PET (polyethylene terephthalate) resin is used. For the sealing material 6, for example, epoxy resin is used.

In the above structure, when a power source is connected to the lead wires 7 and 7, a current flows in parallel to the PTC heating elements 3a through the metal plates 2 and 4, and the PTC heating elements 3a generate heat. As a result, the liquid 3b is heated and the mirror 1 is heated through the metal plate 2. On the other hand, heat dissipation from the metal plate 4 is prevented by the heat insulating material 5. Therefore, the PTC heating element 3
The heat generated by a ... Is efficiently used for heating the mirror 1.

When the temperature of the PTC heating elements 3a ... Raises near the Curie temperature (set to about 50 ° C. in this embodiment), the electrical resistance of the PTC heating elements 3a ... Therefore, the amount of heat generation is reduced, and the temperature is lowered.
When the temperature decreases, the electric resistance of the PTC heating elements 3a ... Decreases again and the amount of heat generation increases. Since the heat generation temperature is self-controlled in this way, it is possible to keep the heat generation temperature constant without providing a temperature control circuit. As a result, the number of parts can be reduced and the manufacturing cost can be reduced.

Moreover, since the periphery of the PTC heating elements 3a ... Is filled with the highly insulating liquid 3b, the metal plate 2
The elliptical portion of the mirror 1 in contact with can be heated uniformly. Thereby, a high anti-fog effect can be obtained. Also, the metal plate 2
Since water vapor does not condense between the four, PTC heating element 3a
The short circuit of ... will not occur. Thereby, a highly reliable anti-fog mirror can be realized.

[0019]

As described above, the anti-fog mirror of the present invention is
An electrically insulating liquid is filled between the first and second metal plates so as to surround the heating element, and the peripheries of the first and second metal plates are sealed to prevent the liquid from leaking.
When a voltage is applied between the first and second metal plates, a current flows through the heating element to generate heat. At this time, the liquid is heated to a constant temperature by the self-temperature control function of the positive temperature characteristic thermistor, and the mirror is efficiently heated through the first metal plate. Thereby, a high anti-fog effect can be obtained. Moreover, the first
Since dew condensation of water vapor does not occur between the second metal plate and the second metal plate, it is possible to prevent short-circuiting of the heating element and obtain a highly reliable anti-fog mirror.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a schematic structure of an anti-fog mirror of the present invention.

FIG. 2 is a bottom view showing a part of the anti-fog mirror shown in FIG. 1 in a cutaway manner.

FIG. 3 is a plan view of the anti-fog mirror shown in FIG.

[Explanation of symbols]

 1 mirror 2 metal plate (first metal plate) 3a PTC heating element 3b liquid 4 metal plate (second metal plate) 5 heat insulating material 6 sealing material

Claims (1)

[Scope of utility model registration request] 1. An anti-fog mirror in which a heating element composed of a positive temperature coefficient thermistor is provided on a first metal plate fixed to the back surface of the mirror, and a second metal plate is provided on the heating element. An insulating liquid is filled between the first and second metal plates so as to surround the heating element, and the peripheries of the first and second metal plates are sealed to prevent the liquid from leaking. Anti-fog mirror.