JPH0546373U - Anti-fog mirror - Google Patents

Abstract

(57) [Summary] [Structure] The heat transfer plate 2 is provided in close contact with the rear surface of the mirror 1. A PTC heater 3 composed of a positive temperature coefficient thermistor is fixed in close contact with the back surface of the heat transfer plate 2. [Effect] PTC heater 3 consisting of positive temperature coefficient thermistor
Can have a self-temperature control function, so that the temperature control circuit and the overheat prevention circuit, which are conventionally required, can be omitted, and the PTC heater 3 has one surface of the heat transfer plate 2
Since it is closely attached and fixed to the back surface of the vehicle, it is possible to avoid the conventional ignition due to local overheating. Therefore, the above configuration can be downsized and is excellent in safety.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an anti-fog mirror including a constant temperature heater, for example, a plate heater made of barium titanate-based porcelain semiconductor having PTC characteristics so as not to be fogged in a high humidity room such as a bathroom.

[0002]

[Prior Art]

 Conventionally, in order to prevent fogging of a mirror in a high humidity room such as a bathroom, a film having an anti-fog effect has been attached to the surface of the mirror, or a paint having an anti-fog effect has been applied to the surface of the mirror. A cloudy mirror is used.

However, in the above and the above, since the film and the coating material are exposed, there is a problem that they are easily peeled off due to humidity and temperature change, and further, they are aged and the function of the anti-fog is apt to deteriorate.

Therefore, in order to avoid the above-mentioned problems, a film-shaped heating element, which is obtained by applying a heating coating material such as carbon or metal on the surface of a sheet-shaped heating element, for example, a heat-resistant polymer film, is provided on the back surface of the mirror. There is known an anti-fog mirror that has a function of preventing fog by sticking it so that it is not exposed and then energizing its heating element to generate heat and transmitting the heat to the mirror to heat the surface of the mirror.

[0005]

[Problems to be solved by the device]

 However, the above conventional anti-fog mirror requires a temperature control circuit to keep the heat generation temperature at a predetermined temperature, and a circuit to prevent overheating is also required to ensure safety. The problem that the anti-fog mirror becomes larger, and if a film-like heating element is attached to the mirror and an air layer is created between them, the film-like heating element in the raised part escapes heat when energized. Since there is no place, there is a problem that it overheats locally and catches fire, which is dangerous.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the anti-fog mirror of the present invention is provided with a heat transfer plate in close contact with the rear surface of the mirror, and a heating element composed of a positive temperature coefficient thermistor has one surface on the back surface of the heat transfer plate. It is characterized by being closely attached.

[0007]

[Action]

 According to the above configuration, the heating element composed of the positive temperature coefficient thermistor can have the self-temperature control function, so that the temperature control circuit and the overheat prevention circuit which have been conventionally required can be omitted, and the heating element can be omitted. However, since its one surface is fixed in close contact with the back surface of the heat transfer plate, it is possible to avoid the conventional ignition due to local overheating.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. In the anti-fog mirror, as shown in FIG. 1, a heat transfer plate 2 is provided in close contact with a back surface of the mirror 1 at a predetermined position, for example, a position where a face is just photographed. A plurality of PTC heaters (heating elements) 3 made of an annular positive temperature coefficient thermistor are attached to the back surface at predetermined intervals, and further, the mirror 1, the heat transfer plate 2 and the back side of each PTC heater 3 ... A heat insulating material 4 made of foamed resin, for example, a hard urethane foam is provided so as to closely adhere to and cover. Further, since the heat transfer plate 2 is used as a current-carrying medium, the current-carrying electrode 5 is provided below the rear surface of the heat-transfer plate 2.

As the heat transfer plate 2 as described above, as shown in FIG. 2, for example, a metal plate having a good heat transfer property formed into a length of 200 mm, a width of 200 mm, and a thickness of 3 mm, for example, an aluminum plate is used. The heat transfer plate 2 has mounting holes 2a for mounting the PTC heater 3 at the center of the heat transfer plate 2 and a predetermined distance from the center to the four corners, for example, 100 mm at a total of 5 positions. Further, the electrode hole 2b for the electrode 5 is formed at a position 10 mm below the heat transfer plate 2, for example, above the center of the lower side.

When the PTC heater 3 and the electrode 5 are mounted using, for example, a flat head screw 6 having a small diameter of 3 mm and a large diameter of 6 mm, as shown in FIG. 1, the mounting holes 2a ... The heat transfer plate front surface 2c of the heat transfer plate 2 attached to the mirror 1 is formed into a shape in which the flat head 6b of the flat head screw 5 of the flat head screw 5 for fixing the PTC heater 3 is fitted.

Therefore, as shown in FIG. 3, the mounting holes 2a ... And the electrode holes 2b are cylindrical portions at a predetermined distance from the heat transfer plate rear surface 2d side of the heat transfer plate 2, and heat transfer from there to the tip. 2b has a taper-shaped portion whose diameter increases toward the plate front surface 2c, and the size of each of the holes 2a ... 2b is particularly limited as long as it corresponds to the shape size of the flat head screw 6. In the above case, a small diameter of 4 mm and a large diameter of 6 mm are used, though not necessarily.

The PTC heater 3 is made of a material having a positive temperature coefficient (Positive Temperature Coefficient), for example, a ceramic semiconductor whose main material is barium titanate, and has a low temperature from room temperature to the Curie temperature Tc (rapid change temperature). Although it is a resistance, it is a positive temperature coefficient thermistor as a heat sensitive element having a characteristic that the resistance value sharply increases when it exceeds the Curie temperature Tc.

When a voltage is applied to the PTC heater 3 due to this characteristic, initially, the resistance is low, so that the initial power consumption is large and the temperature rises rapidly, and when the temperature exceeds the Curie temperature, the resistance value sharply increases. As a result, power consumption is significantly reduced. As a result, the PTC heater 3 does not rise above a certain temperature and maintains a stable temperature, and has a self-temperature control function.

The Curie temperature Tc of this PTC heater 3 can be arbitrarily set within the range of about 30 to 250 ° C. depending on the material composition. In the PTC heater 3 in the above-described embodiment, the surface temperature of the mirror 1 effective for preventing fog is reduced. The Curie temperature Tc is set in consideration of safety and power saving.

The shape and size of the PTC heater 3 is not particularly limited, but in the above case, depending on the size of the mounting hole 2a, an annular shape having an inner diameter of 4 mm, an outer diameter of 15 mm and a thickness of 2 mm is used. Is molded into.

Next, the attachment of the PTC heater 3 to the heat transfer plate 2 will be described. As shown in FIG. 4, first, a tape-shaped insulating seal 7 is wrapped around the outer periphery of the screw portion 6a of the flat head screw 6. , The flat head screw 6 is inserted into the mounting hole 2a from the front surface 2c of the heat transfer plate. Then, the hollow portion of the PTC heater 3 is fitted into the screw portion 6a of the dish screw 6 protruding from the rear surface 2d of the heat transfer plate in the mounting hole 2a.

After that, the lead wire 8 is soldered 8a to the peripheral portion of the rear electrode surface 3b opposite to the front electrode surface 3a which is in contact with the heat transfer plate 2 of the PTC heater 3. Then, an insulating film plate 9 formed by molding a resin having excellent electric insulation properties and elasticity, for example, polypropylene into a washer shape which is a sheet-shaped donut shape is filled in the dish 6 from the rear electrode surface 3b side.

After that, the flat head screws 6 are tightened with bolts 6c to bring the front electrode surface 3a of the PTC heater 3 into close contact with the rear surface 2d of the heat transfer plate. At this time, since the large diameter of the flat head 6b of the flat head screw 6 and the large diameter of the taper portion of the mounting hole 2a are set to the same diameter, the flat head of the heat transfer plate 2c and the flat head of the mounting hole 2a are set. The top of 6b is on a plane.

In this manner, the PTC heaters 3 ... Are attached to the mounting holes 2a .. On the other hand, in the same manner as the PTC heater 3 attachment, the electrodes 5 are attached to the heat transfer plate 2 using the flat head screws 6 similar to the above. The heat transfer plate 2 is attached to the electrode hole 2b.

Subsequently, although not shown, the heat transfer plate 2 to which the PTC heaters 3 ... And the electrodes 5 are attached as described above is attached to a predetermined position on the back surface of the mirror 1, and then the mirror 1, The heat insulating material 4 shown in FIG. 1 is formed so as to tightly cover the back surfaces of the heat transfer plate 2, the PTC heater 3 and the flat head screw 6 to complete the anti-fog mirror.

The configuration of the above-mentioned embodiment is used in a room where the mirror 1 is liable to become cloudy due to high humidity such as a unit bath or a washroom installed adjacent to the unit bath, and the heat transfer plate 2 is used, for example, as a face. It can be attached to the rear part of the mirror 1 at the height position where the image of is reflected to prevent the clouding of only the part where the face is reflected, which is particularly convenient for making up the face.

Further, in the above configuration, since the PTC heater 3 is used as a heat generating means, the temperature rises quickly after passing electricity, and when the temperature reaches a predetermined temperature, the temperature is maintained, and thus the surface of the mirror 1 is Rapidly rises to a predetermined temperature, and exerts an effect of preventing fog on the surface of the mirror 1.

By the way, conventionally, there is known an anti-fog mirror having an anti-fog function by providing an anti-fog film or paint film on the surface of the mirror, and such an anti-fog mirror is used in a bathroom or the like where the humidity is high. When installed in a room, the use environment will inevitably have high humidity, so the film and other film-like substances will harden and yellow due to aging, and the anti-fog function will result from repeated thermal expansion and peeling due to thermal contraction. Was being deteriorated.

However, in the above configuration, it is not necessary to provide a film-like substance having such a function on the surface of the mirror 1, and deterioration of the anti-fog function and yellowing due to the aging of such a film-like substance do not occur. .. Further, since the countersunk screw 6 is used to fix the PTC heater 3, it is possible to prevent the conventional accident such as the exfoliation of the heating element adhered to the mirror. Therefore, it can be expected that the anti-fog effect will be maintained semi-permanently.

Further, in the conventional anti-fog mirror in which a planar heating element is attached to the back of the mirror, a temperature control circuit is necessary to keep the heat generation temperature constant, and further, a circuit for preventing overheating is required. This also necessitates the problem of increasing the size of the anti-fog mirror, and on the other hand, the printing pattern of the anti-fog mirror equipped with a heating element to which a sheet heating element made by printing is attached The problem is that it is difficult to design, and if an air layer is created between the planar heating elements when they are attached to the mirror, the heating elements in the raised parts will not carry heat away when energized. Therefore, there was a problem that there was a risk of ignition due to local overheating.

However, in the above configuration, since the PTC heater 3 has a self-temperature control function, a temperature controller such as a thermostat or an electric circuit for temperature control is not necessary, and an overheat prevention circuit is not necessary. Since there is no such temperature control mechanism, the temperature control reliability is improved, the size and weight can be reduced, and the safety can be improved. Further, the PTC heater 3 has a stable calorific value. Since it is only necessary to attach the heat transfer plate 2 to the mirror 1, heat generation can be easily designed.

Further, since the number of electric circuits and the like that are more likely to cause a failure than in the past is reduced, failures due to contact failures are reduced. In addition, since the heat transfer plate front surface 2c is provided in close contact with the rear surface of the mirror 1, and further, the heat insulating material 4 which covers the PTC heater 3 in close contact with the heat transfer plate rear surface 2d from the rear surface is provided. , The heat from the PTC heater 3 can be transferred to the mirror 1 without waste, and the power saving of the anti-fog mirror can be achieved.

As a result of the above, with the above-mentioned configuration, it is possible to provide a safe and economical anti-fog mirror that has fewer failures than conventional ones, can be miniaturized.

Note that the switch of the PTC heater 3 having the above-described configuration may be interlocked with, for example, a lighting switch in the bathroom, or a humidity sensor may be provided in the bathroom and the PTC may be output based on a signal from the humidity sensor. The energization of the heater 3 may be controlled.

In the configuration of the above embodiment, an example in which the electric insulation between the flat head screw 6 and the PTC heater 3 is made by using the insulating seal 7 and the insulating film plate 9 and the soldering 8a is made for the electric connection However, as shown in FIG. 5, a pedestal 10 made of a resin having excellent electric insulation, for example, polycarbonate, and a metal washer-shaped crimp terminal 11 may be used.

The pedestal 10 is formed in a shape having a cylindrical portion and a flange portion that extends outward in the radial direction at one end thereof. A crimp terminal 11 is used to connect the flange portion of the pedestal 10 and the PTC heater 3 to each other. The PTC heater 3 is fixed to the rear surface 2d of the heat transfer plate by being sandwiched between the cylindrical portion of the pedestal 10 and the screw portion 6a of the flat head screw 6.

As a result, compared to the case where the insulating seal 7 is used, the electrical insulation can be more reliably ensured, the soldering 8a can be omitted, and thermal destruction of the PTC heater 3 can be avoided. ..

[0033]

[Effect of the device]

 As described above, the anti-fog mirror of the present invention is provided with a heat transfer plate in close contact with the back surface of the mirror, and a heating element composed of a positive temperature coefficient thermistor is fixed with one surface thereof in close contact with the back surface of the heat transfer plate. It is a configured structure.

Therefore, since the heating element composed of the positive temperature coefficient thermistor can have the self-temperature control function, it is possible to omit the temperature control circuit and the overheat prevention circuit, which have been conventionally required, and the heating element can be Since one surface of the heat transfer plate is closely attached to and fixed to the back surface of the heat transfer plate, it is possible to avoid the conventional ignition due to local overheating.

As a result of the above, the above-described configuration has an effect that it can be downsized and is excellent in safety.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an anti-fog mirror of the present invention.

FIG. 2 is a front view of a heat transfer plate in the anti-fog mirror.

FIG. 3 is a cross-sectional view of an essential part of a heat transfer plate showing the shape of a mounting hole in the heat transfer plate.

FIG. 4 is a cross-sectional view of essential parts of the anti-fog mirror, showing how the PTC heater is attached to the anti-fog mirror.

FIG. 5 is a cross-sectional view of a main part of an anti-fog mirror showing a modified example of mounting the PTC heater in the anti-fog mirror.

[Explanation of symbols]

 1 Mirror 2 Heat transfer plate 3 PTC heater (heating element)

Claims (1)

[Scope of utility model registration request] 1. A heat transfer plate is provided in close contact with the rear surface of the mirror, and a heating element composed of a positive temperature coefficient thermistor is fixed in close contact with one surface thereof to the back surface of the heat transfer plate. Anti-fog mirror.