CN1969592A - Ceramic heater and production method therefor and heating device and hair iron - Google Patents

Abstract

A ceramic heater, comprising: a ceramic body having an outer surface and a buried conductor pattern, the conductor pattern being formed of a conductor provided so as to form a turn-back portion of a resistance heating element, The pore occupancy rate of the ceramic part sandwiched by the adjacent conductors in the folded part is in the range of 0.01 to 50%. Thereby, a ceramic heater capable of preventing insulation degradation under high-temperature conditions and having excellent durability is provided.

Description

Ceramic heater, manufacturing method thereof, heating device, and hair iron

technical field

The present invention relates to a heater for sensor heating, in particular to a ceramic heater used for heating an air-fuel ratio detection sensor for automobiles, a heater for a carburetor, a hair iron, a soldering iron, etc., and a heater composed of the same Appliances and hair irons.

Background technique

Alumina ceramic heaters in which heating resistors made of high-melting-point metals such as W, Re, and Mo are embedded in ceramics mainly composed of alumina have been widely used.

For example, when manufacturing a cylindrical ceramic heater, as shown in FIG. 10 , a ceramic molded body 12 and a ceramic green sheet 13 are prepared, and a heating element composed of a refractory metal such as W, Re, or Mo is formed on one surface of the ceramic green sheet. Resistor 14 and lead-out portion 15 are formed with electrode pads on the back (the other side), and ceramic molded body 12 is wound and fired in close contact with heating resistor 14 and lead-out portion 15 inside. Wherein, the lead-out part 15 and the electrode pad are connected through the through hole 16 formed in the ceramic green sheet (for example, refer to Patent Document 1).

In this way, the conventional ceramic heater is formed by simultaneously firing the paste heating resistor 14 , the ceramic molded body 12 and the ceramic green sheet 12 . Then, the heat-generating resistor of the ceramic heater produced in this way is folded many times to form a zigzag shape (see FIG. 1 of Patent Document 2, etc.).

In addition, Patent Document 3 to Patent Document 5 disclose the following content: the bases of a pair of gripping members are freely opened and closed by shafts, and the front ends of the two gripping members are usually opened to each other by the tension of the spring set in the bearing portion. At the same time, the hair iron is provided with a heating plate inside the openings at the front ends of the two holding members.

The hair iron has the following structure: a nickel-chromium electric heating wire is wound on a ceramic insulating plate, and the heating plate covered by the insulating plate is pressed on the plate body on both sides; The heat is transferred to the plate-like body.

Patent Document 1: JP-A-2001-126852

Patent Document 2: JP-A-2001-102156

Patent Document 3: JP-A-2000-232911

Patent Document 4: JP-A-2002-291517

Patent Document 5: JP-A-2000-14438

However, recently, ceramic heaters have been used in higher temperature environments, and thus a decrease in durability has become a problem. That is, when continuous energization is performed at a high temperature, the insulation between adjacent patterns deteriorates, the durability decreases, and problems such as sparking and disconnection occur in the end.

In addition, the heater made by winding the heating element composed of nickel-chromium electric heating wire on the insulating plate will be disconnected due to repeated heating and energization, and the heating element will react with the moisture in the air to form a reaction layer, and the resistance value of the heating element will change. If it is too large, there is a danger that a certain temperature cannot be reached under a certain voltage, and there are problems of reduced durability.

In addition, the heating plate made of nickel-chromium heating wire is difficult to evenly install the heating element on the heating plate, and there is a problem that the heating surface of the plate-shaped body cannot be heated uniformly.

In addition, since the heating surface of the heating plate and the surface of the plate-shaped body are not in contact with each other with the same heat, it is difficult for the heat of the heating plate to spread uniformly on the plate-shaped body, and there is a problem that the temperature of the heating surface is not uniform.

Contents of the invention

A first object of the present invention is to provide a ceramic heater having good durability by preventing insulation degradation at high temperatures by taking advantage of the components formed above.

In addition, the second object of the present invention is to provide a heating device and a hair iron capable of uniformly heating a heating surface of a plate-shaped body.

In order to achieve the first object above, the ceramic heater according to the present invention is characterized in that it includes a ceramic body having an outer surface and a buried conductor pattern, the conductor pattern is composed of a conductor, and the conductor is formed as The form of the turn-back portion of the resistance heating element is provided, and the pore occupancy rate of the ceramic portion sandwiched by the adjacent conductors in the turn-back portion is 0.01 to 50%.

Here, the ceramic portion sandwiched between the adjacent conductors is defined as a ceramic portion sandwiched between the conductors in an inner region along the outer surface that has substantially the same thickness as the conductor.

In addition, the first manufacturing method of the ceramic heater of the present invention is characterized in that it includes:

a step of forming a conductor paste in a predetermined pattern on the surface of the first ceramic green sheet,

and a second ceramic green sheet having at least the same thickness as the conductive pattern and being softer than the first ceramic green sheet is laminated on the surface of the first ceramic green sheet on which the conductor paste is formed to produce a ceramic green sheet laminate process,

and a step of bonding the ceramic green sheet laminate to the ceramic molded body,

and firing the bonded ceramic green sheet laminate and ceramic molded body.

In addition, the second manufacturing method of the ceramic heater of the present invention is characterized by comprising:

The process of forming a conductor paste on the surface of a ceramic green sheet according to a prescribed pattern,

and the process of filling insulators between the conductor pastes in the above prescribed pattern,

and a step of bonding the ceramic green sheet filled with an insulator between the conductor paste to the ceramic molded body using the surface on which the conductor paste is formed as the bonding surface,

and firing the bonded ceramic green sheet and ceramic molded body.

In addition, in order to achieve the second object above, the heating device of the present invention is characterized by comprising:

a heating plate, which is composed of a plate-shaped ceramic body embedded with a resistance heating element, and has a thickness ranging from 0.5 to 5.0 mm; and

A plate-shaped body has a first surface and a second surface, the heating plate is provided on the first surface, the second surface is used as a heating surface, and the heating surface is composed of a flat surface and a chamfered portion around the surface.

The hair iron of the present invention is characterized in that it is constructed by using the ceramic heater of the present invention or the heating device of the present invention.

In the ceramic heater according to the above invention, since the pore occupancy rate of the ceramic body between conductors is 0.01 to 50%, it is possible to provide a ceramic heater with high durability by preventing a decrease in insulation performance under high temperature conditions.

That is, in the invention of the ceramic heating body, it was found that if the pore occupancy rate of the ceramic part between the above-mentioned conductors is within a certain range, it is possible to prevent the insulation from being lowered under high temperature conditions, and completed the present invention.

In addition, since the heating device of the present invention embeds the resistance heating element in the plate-shaped ceramic body, there is no situation in which the resistance heating element is exposed to water vapor or the like, so it has excellent durability, can repeat rapid heating at the same time, and can heat the inside of the surface. The temperature difference can be very small, so it is possible to heat the object evenly.

Furthermore, the hair iron according to the present invention can have high durability by including the ceramic heater of the present invention or the heating device of the present invention.

In addition, in the hair iron of the present invention, by including the heating device of the present invention, since no local high-temperature portion is generated on the heating surface, it is possible to provide a hair iron that does not cause damage due to partial high-temperature heating, for example. .

Description of drawings

FIG. 1 is a partially cutaway perspective view showing the structure of a ceramic heater according to Embodiment 1 of the present invention.

Fig. 2 is a sectional view taken along line X-X of the ceramic heater of Fig. 1 .

3 is an enlarged cross-sectional view showing between conductors of the cylindrical ceramic heater according to Embodiment 1. FIG.

4 is an enlarged cross-sectional view showing between conductors of a flat ceramic heater according to a modified example of Embodiment 1. FIG.

Fig. 5 is a side view showing a cutout of a constituent part of the hair iron according to Embodiment 2 of the present invention.

Fig. 6 is a front view showing the positional relationship between the heating plate and the plate-shaped body to which the hair iron shown in Fig. 5 is applied.

Fig. 7 is a sectional view taken along line X-X in Fig. 6 .

8 is a cross-sectional view showing a heating device according to a modified example of Embodiment 2 of the present invention.

FIG. 9 is a plan view showing a heating plate used in the heating device according to Embodiment 2. FIG.

Fig. 10 is a developed view of a conventional ceramic heater.

In the figure: 1-ceramic heater, 2-ceramic core material, 3-ceramic sheet, 4-heating resistor, 5-lead lead out part, 6-through hole, 7-electrode plate, 8-lead parts, A- The area between the conductors of the cylindrical ceramic heater, B- the area between the conductors of the flat ceramic heater, 5- the heating device, 50- the holding part, 52- the shaft, 53- the coil spring, 54- the bearing part, 55- the plate body, 55a-heating surface, 57-heating plate, 58-resistance heating element, 59-spring, 61-lead wire.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1

Fig. 1 is a partially cutaway perspective view of a ceramic heater 1 according to Embodiment 1 of the present invention. Fig. 2 is an X-X sectional view of Fig. 1 .

The ceramic heater 1 according to Embodiment 1 is characterized in that a heating resistor 4 is incorporated in a ceramic body composed of a ceramic core material 2 and a ceramic sheet 3 . Here, the heating resistor 4 is constituted by the turned-back portion of the conductor pattern, and the portion where the heating resistor 4 is formed has a void occupancy rate of 0.01 to 50% in the ceramic body between adjacent conductors.

This ceramic heater 1 is to form heating resistor body 4 and lead wire lead-out part 5 on the surface; Form the ceramic green sheet (ceramic sheet 3 after firing) of electrode plate 7 on the back, make heating resistor body 4 and lead wire lead-out part 5 becomes the inner side, is wound on a ceramic molded body (ceramic core material 2 after firing), and is obtained by close-contact firing. Wherein, the lead-out part 5 and the electrode pad 7 are connected through the through hole 6 formed on the ceramic sheet 3 .

The ceramic body is composed of a ceramic core material 2 fired into a ceramic molded body and a ceramic sheet 3 fired into a ceramic green sheet. The ceramic body is composed of various ceramics such as alumina ceramics, silicon nitride ceramics, aluminum nitride ceramics, and silicon carbide ceramics, and it is particularly preferable to use alumina or silicon nitride as an important component, thereby obtaining Rapid heating and excellent durability ceramic heater 1. For example, when aluminum oxide (Alumina) is used, it is preferable to use Al ₂ O ₃ : 88 to 95% by weight, SiO ₂ : 2 to 7% by weight, CaO: 0.5 to 3% by weight, MgO: 0.5 to 3% by weight, ZrO ₂ : Alumina composed of 1 to 3% by weight. If the Al ₂ O ₃ content is less than 88% by weight, the glassiness increases, and there is a risk of increased migration during energization. On the other hand, if the Al ₂ O ₃ content exceeds 95% by weight, the amount of glass diffused into the metal layer of the built-in heating resistor 4 decreases, and the durability of the ceramic heater 1 may deteriorate. In addition, when silicon carbide ceramics are used, relative to the main component of silicon nitride, 3 to 12% by weight of rare earth element oxides and 0.5 to 3% by weight of Al ₂ O ₃ are preferably used as sintering aids, and furthermore, as the sintered body contained in SiO ₂ amount, SiO ₂ mixed to 1.5 to 5% by weight as much as possible. The amount of SiO ₂ shown here is the sum of SiO ₂ generated by oxidation of impurities contained in the silicon nitride raw material, SiO ₂ of impurities contained in other additives, and SiO ₂ intended to be added. In addition, by dispersing MoSi ₂ or WSi ₂ in the base material silicon nitride, the thermal expansion coefficient of the base material is close to that of the heating resistor 4 , thereby improving the durability of the heating resistor 4 .

In addition, the heating resistor 4 is composed of a meandering conductor pattern, and is connected to the lead wire lead-out portion 5 whose resistance value relative to the heating resistor 4 is about 1/10. Usually, in order to simplify these operations, it is often the case that the heating resistor 4 and the lead-out part 5 are simultaneously printed and formed on the ceramic green sheet (the ceramic sheet 3 is formed after firing). Among them, the folded portion of the present invention is a member having a U-shaped folded shape or a meandering shape in order to achieve a desired resistance value.

Here, the size of the ceramic heater 1 may be, for example, about 2 to 20 mm in width and 40 to 200 mm in length without the outer diameter. As the ceramic heater 1 for heating an automobile air-fuel ratio sensor, the outer diameter and width are preferably 2 to 4 mm, and the length is 50 to 65 mm. In addition, in terms of automotive applications, it is preferable that the heating length of the heating resistor 4 be 3 to 15 mm as much as possible. When the heat generation length is shorter than 3mm, the temperature rise at the time of energization can be rapid, but the durability of the ceramic heater 1 is reduced. When the heating length is longer than 15 mm, the temperature rise rate becomes slow, and if the temperature rise rate is to be accelerated, the power consumed by the ceramic heater 1 must become larger, so it is not preferable to use it. Here, the heating length is the length in the longitudinal direction of the meandering heating resistor 4 shown in FIG. 1 , and the heating length is appropriately selected according to the intended use.

Here, although the boundary line is drawn between the ceramic core material 2 and the ceramic sheet 3 in FIG. 2 , in fact, after the unfired ceramic molded body is bonded to the ceramic green sheet, it is not regarded as the case that the ceramic green sheet is fired a lot. Boundary of the bonding surface.

In the first embodiment, it is preferable to form a post-firing primary plating layer on the electrode pad 7 of the ceramic heater 1 . This primary plating layer has the effect of improving the solder flow when soldering the lead member 8 on the surface of the electrode pattern 7 and increasing the soldering strength. The thickness of the primary plating layer is preferably 1 to 5 μm, since the adhesion force increases. As the material of the primary plating layer, Ni, Cr, or a composite material mainly composed of these components is preferable, and plating mainly composed of Ni, which is excellent in durability, is more preferable.

In addition, when used in a high-humidity atmosphere, it is preferable to use Au-based or Cu-based brazing materials because migration is less likely to occur. As the brazing material, Au, Cu, Au—Cu, Au—Ni, Ag, and Ag—Cu-based substances having high heat resistance are preferable. In order to improve durability, Au—Cu brazing, Au—Ni brazing, and Ag—Cu brazing are more preferable. In general, it is preferable to form a secondary plating layer made of Ni on the surface of the brazing material in order to improve high-temperature durability and protect the brazing material from corrosion.

In addition, as the material of the lead member 8, since the temperature of the lead member 8 rises due to the heat passing through the heating resistor 4 during use, Ni-based or Fe-Ni-based alloys with good heat resistance are preferably used.

Moreover, the present invention is characterized in that in the ceramic heater 1 with a built-in conductor pattern, the conductor pattern has a turn-back portion constituting the heating resistor 4, and in the turn-back portion, the voids of the ceramic body between any adjacent conductors occupy The rate is 0.01 to 50%. Furthermore, the pore occupancy rate of the ceramic body between any adjacent conductors in the folded portion is more preferably 0.1 to 40%, and still more preferably 1 to 20%. When the pore occupancy rate is less than 0.01%, if the rapid heating and rapid cooling are repeated, when the heating resistor 4 of the heating part is heated and expanded, the heat dissipation of the ceramic around the heating resistor 4 is insufficient, and the thermal expansion of the ceramic body cannot follow. The thermal expansion of the heating resistor 4 causes stress to concentrate on the edge portion 41 of the heating resistor, and there is a risk of fracture and disconnection. On the other hand, when the pore occupancy rate exceeds 50%, the insulation of the ceramic body around the heating resistor 4 in the heating portion tends to deteriorate and durability tends to decrease when current is continuously applied at a high temperature. However, when the ceramic green sheet is directly bonded to the ceramic molded body and fired in close contact, the pore occupancy rate becomes a value larger than the above range. Therefore, in order to achieve the porosity in the above-mentioned range, the following production method was employed.

2 is a sectional view showing an example of a section perpendicular to the longitudinal direction (X-X line sectional view shown in FIG. 1 ), showing that the conductor at the turn-back portion (heating resistor 4) of the conductor pattern is circular on the outer periphery of the ceramic core material 2. Configuration method. Here, the pore occupancy rate of the ceramic body between conductors is 0.01-50%, which means that the pore occupancy rate of the ceramic body between any adjacent conductor patterns (4a and 4b in FIG. 3 ) is 0.01-50%. Therefore, the portion of the ceramic body with a pore occupancy rate of 0.01 to 50% may be any portion of the cross-section of the heating resistor 4 cut in a direction perpendicular to the longitudinal direction. Wherein, between so-called conductors, when the ceramic body is cylindrical, as shown in Figure 3, it is along the outer circumference of the ceramic core material 2 (in other words, the outer surface of the ceramic body) connecting the lines on the top of the adjacent conductors 4a and 4b. , and the line connecting the lower edge of the conductor 4a and the lower edge of the 4b along the outer circumference of the ceramic core material 2, in the area of the area A covered by the surface of the conductor 4a, 4b; in addition, when the ceramic body is flat, as shown in Figure 4 Shown, is the line connecting the upper side of the adjacent conductor 4c and the upper side of 4d, and the line connecting the lower side of the conductor 4c and the lower side of the conductor 4d, covering the region B on the surface of the conductors 4c and 4d.

In addition, in this specification, the so-called conductor formation region refers to the annular region sandwiched between the outer circumference of the ceramic core material 2 and the outer circumference along the outer circumference from the outer circumference to the outer circumference of the outer conductor thickness when the ceramic body is cylindrical. ; When the ceramic body is in the form of a flat plate, the internal area sandwiched between the connecting wires that connect the upper sides of the conductors and the connecting wires that connect the lower sides of the conductors. That is, as defined above, between conductors is a portion between adjacent conductors in the conductor formation region.

Furthermore, in the ceramic heater according to Embodiment 1, the length along the outer surface of the void existing between adjacent conductors is preferably 1/2 or less of the conductor interval. That is, in the conductor pattern turn-back portion, along any line connecting adjacent conductors along the outer surface, it is preferable that there is no void whose length exceeds 1/2 of the line length (distance between conductors) in the ceramic body between the conductors. . When the length of the void exceeds 1/2 of the distance between the conductors, the insulation of the ceramic body covering the heating resistor 4 of the heating part deteriorates when continuous current is applied under high temperature conditions, and thus the durability deteriorates. Wherein, the so-called random line refers to any line connecting the adjacent conductors 4a and 4b in the area A along the outer surface when it is a cylindrical ceramic heater as shown in FIG. 3 . The arbitrary line at this time is the center of the circle formed by the outline (outer surface of the ceramic body) of the sectional view of the cylindrical ceramic heater as shown in FIG. 3 and an arc-shaped curve having approximately the same center; In the case of a flat ceramic heater as shown in FIG. 4, an arbitrary straight line connecting adjacent conductors 4c and 4d in the area B is called an arbitrary line.

Furthermore, in the present invention, the thickness of the conductive pattern, especially the conductor constituting the heating resistor is preferably 5 to 100 μm. When the thickness of the conductor pattern is less than 5 μm, although it is possible to prevent voids adjacent to any of the above-mentioned conductors, the resistance change and disconnection of the heating resistor 4 in the heating part will be caused during the high-temperature continuous durability test and high-temperature cycle durability test. deteriorating. On the other hand, when the thickness of the conductor pattern exceeds 100 μm, it tends to be difficult to suppress the porosity between any adjacent conductors to 50% or less.

Next, a method for achieving a pore occupancy rate of 0.01 to 50% in the ceramic body between adjacent arbitrary conductors will be described.

As an example, the following method may be adopted: a conductor pattern is formed on the surface of the first ceramic green sheet, and the conductor pattern is formed on the side of the first ceramic green sheet to form a laminate having a thickness at least substantially the same as that of the conductor pattern, preferably having the same thickness than the first ceramic green sheet. The ceramic green sheet is a softer second ceramic green sheet. According to this method, voids between patterns can be eliminated by embedding the soft second ceramic green sheet in the voids in the thickness portion of the conductor pattern. Here, the second ceramic green sheet needs to be softer than the first ceramic green sheet, because when the second ceramic green sheet is soft, when the second ceramic green sheet is bonded to the first ceramic green sheet on which the conductor pattern is implemented, at least the gap between the conductors will be damaged. In the central part, the two ceramic green sheets can be closely bonded. Here, the hardness of the ceramic green sheet is measured with a digital indicator (manufactured by Mitto), and it is preferable that a needle with a diameter of 1 mm penetrates to a depth of 200 μm or more in 30 seconds. When the hardness of the ceramic green sheet, that is, the aforementioned intrusion depth is less than 200 μm, voids are formed because conductors cannot be in close contact with each other. However, in order to reduce the gap between the patterns, pressure can be applied using a press or the like.

In addition, as another method, the method of screen printing paste can be used. The method is accomplished as described below. First, the heating resistor 4 and the lead-out portion 5 are screen-printed on a ceramic green sheet. At this time, the paste applied by screen printing is an organic resin-based binder composed of a powder composed mainly of a high-melting point metal (W, Mo, Re, etc.) and an adhesive component, mainly ethyl cellulose , nitrocellulose and the organic solvents used as diluents, mainly TPO (terpineol), DBP (dibutyl phthalate), DOP (dioctyl phthalate), BCA (diethylene glycol Alcohol butyl ether acetate) and other substances formed. These pastes were printed at an original thickness ranging from 5 to 150 μm. In addition, the conductor pattern is formed by adjusting the line width, printing thickness, specific resistance of the paste, etc. so that the resistance value of the heating resistor 4 becomes approximately 10 times the resistance value of the lead lead-out portion 5 . Then, the paste containing the insulator is screen-printed in order to fill the voids adjacent to the thick portion between the conductors. At this time, the paste used is made of high melting point insulator, which is mainly composed of the same composition as the ceramic green sheet, that is, Al ₂ O ₃ : 88-95% by weight, SiO ₂ : 2-7% by weight, CaO: 0.5-3% by weight, Alumina ceramics composed of MgO: 0.5 to 3% by weight and ZrO ₂ : 1 to 3% by weight are mixed with an organic resin-based binder composed of bonding components, mainly ethyl cellulose, nitrocellulose and diluent The organic solvents used in the agent are mainly TPO (terpineol), DBP (dibutyl phthalate), DOP (dioctyl phthalate), BCA (diethylene glycol butyl ether acetate), etc. formed substance. Furthermore, a single alumina component or an insulating material having a volume resistivity of 108Ω or more may be used as the paste other than the composition of the ceramic green sheet. Here, the viscosity of the paste is preferably adjusted within a range of 50 dPa.s to 1000 dPa.s for printing. When the paste viscosity is less than 50dPa.s, although the printing performance is excellent, due to the low density of the raw material, the drying shrinkage will increase, and there will be a difference in height on the upper side of the conductor pattern, and voids will easily occur after firing. Moreover, when a viscosity is 1000 dPa.s or more, leveling (leveling) property will fall, and a void will generate|occur|produce easily in a film, and it is unpreferable. Among them, screen printing is carried out on a screen in which the heating resistor and the lead-out part are reversed.

Furthermore, as another method, a filling method using a dispenser may be employed. As mentioned above, it is possible to set a high raw material density for materials with a paste viscosity of 1000dPa.s or more. In order to minimize the amount of shrinkage caused by drying shrinkage, although the gaps between conductors can be reliably filled, screen printing The method is not preferred and cannot be used. Therefore, when using such a high-viscosity paste, the filling method using a dispenser can be preferably used.

In this way, the method of using screen printing or applying a dispenser is an effective method in that it is possible to fill insulators not on the conductor pattern but between the conductors.

Among them, in the embodiment of the present invention, it is clearly indicated that the ceramic body is wound with a ceramic green sheet in a cylindrical ceramic molded body, but the present invention also includes: a flat ceramic molded body, or a ceramic green sheet bonded A ceramic body formed by sintering and firing ceramic green sheets printed with conductors and the like.

Embodiment 2

Next, the heating device 51 according to Embodiment 2 of the present invention will be described.

Fig. 5 is a partially broken side view showing a configuration example of a hair iron 100 using a heating device 51 according to the second embodiment. In this Fig. 5, 50 is a holding member, 52 is a shaft connecting a pair of holding members that are freely openable and closed, and 53 is a coil spring installed in a bearing portion 54 to maintain the opening direction of the front ends of the two holding members at ordinary times. . 55 is the plate-shaped body 55 which is respectively fitted into the opening 56 provided in the front-end part of both holding members 50, and faces each other.

FIG. 6 is a front view showing the positional relationship between the heating plate 57 and the plate-shaped body 55 taken out of the heating device 51 in FIG. 5 , and FIG. 7 is a cross-sectional view along line X-X. The heat of the heating plate 57 is transferred to the one main surface 55b of the plate-shaped body through the one main surface 57a of the heating plate 57, so that the heating surface 55a provided on the other main surface of the plate-shaped body 55 can be uniformly heated.

With such a configuration, the plate-shaped body 55 having the large heating surface 55a can be efficiently and uniformly heated using the small heating plate 57 made of ceramics.

That is, the heating device 51 according to Embodiment 2 is composed of a heating plate 57 in which a resistance heating element 58 is embedded in a plate-shaped ceramic body, and a plate-shaped body 55 having a heating surface 55a for heating an object to be heated. The surface 55b is in contact with one main surface 57a of the heating plate 57 described above. Therefore, the present invention is characterized in that the heating surface 55a is composed of a flat surface and a C surface or a chamfered surface of a curved surface provided around the flat surface, and the thickness H of the heating plate 57 is 0.5 to 5 mm. The heating plate 57 embeds a resistance heating element 58 inside the plate-shaped ceramic body, the resistance heating element 58 blocks the air, and the resistance heating element 58 can prevent corrosion caused by moisture in the air. In addition, the resistance heating element 58 embedded in the plate-shaped ceramic body has its own resistance. When printing under a certain power, Joule heats up to a specified temperature, and the heating plate 57 can be used as a heating element to heat up to the required specified temperature.

Therefore, since the above-mentioned heating surface 55a is composed of a flat surface and a C surface or a chamfered portion of a curved surface provided on its periphery, even if the object to be heated is inserted when sliding on the heating surface 55a, there is little risk of damage to the object to be heated. . Thus, when the object to be heated is hair, in order not to damage the hair, when the above-mentioned chamfered portion is the C surface, the size Wc is preferably 0.1 to 5 mm, more preferably 0.3 to 4 mm. More preferably, it is 1 to 3 mm. In addition, when the above-mentioned chamfer is a curved surface, the so-called curved surface is a region formed by a circular arc or a quadratic curve in a section perpendicular to the end surface. When the width Wr is 0.2 to 5 mm, the damage to the heated object is small. preferred. More preferably, it is 0.3 to 4 mm, and more preferably 1 to 3 mm.

In addition, when the thickness H of the heating plate 57 is 0.5 to 5.0 mm, the heat of the heating plate 57 can be efficiently transmitted to the plate-shaped body 55 . If the thickness of the heating plate 57 is less than 0.5 mm, the flatness of one main surface of the plate-shaped body 55 will be as large as 0.02 to 0.2 mm. Therefore, when the heating plate 57 is mounted with stress, the heating plate 57 may be damaged.

In addition, when the thickness of the heating plate 57 exceeds 5mm, even if the heating plate 57 is installed in the plate-shaped body 55, the one main surface 57a of the heating plate 57 is not deformed, and the one main surface 57a of the heating plate 57 and the plate-shaped body 55 Therefore, the heating surface 55a of the plate-shaped body 55 cannot be uniformly heated.

Therefore, when the thickness of the heating plate 55 is 0.5-5mm, the main surface 57a of the heating plate 57 and the main surface 55b of the plate-shaped body 55 can be respectively deformed and matched, so the heating surface 55a can be heated at a widely uniform temperature. More preferably, the heating plate 55 has a thickness of 1 to 3 mm.

Moreover, it is preferable to provide the heat conduction member 63 between the one main surface 55b of the plate-shaped body 55, and the one main surface 57a of the heating plate 57. When the heat conduction member 63 is provided, the heat conduction between the one main surface 57a of the heating plate 57 whose surface roughness is Ra and the one main surface 55b of the plate-shaped body 55 becomes easier, and the heat of the heating plate 57 can be efficiently transferred to the plate-shaped body. 55 is preferred.

The thermally conductive member 63 is preferably made of silicon-based resin or a resin mixed with fine metal particles having high thermal conductivity. Gold, silver, copper, and nickel, which have a high heat transfer rate, are preferable as the metal fine particle powder, and silver is more preferable. In addition, as the resin, silicon-based resin or fluorine-based resin can be used. Furthermore, the heat conduction member can be stretched and slid due to the difference in thermal expansion between the above-mentioned plate-shaped body 55 and the heating plate 57 while there is no gap between the one main surface 55a of the plate-shaped body 55 and the one main surface 57a of the heating plate 57. It is preferable that the heat conduction member 63 keeps the heat conduction between the main surface 55a and the main surface 57a from changing, and can prevent the temperature difference of the heating surface 55a from becoming too large.

In addition, in the heating device 51 of the present invention, it is preferable that the surface roughness Ra of the one main surface 57a of the heating plate 57 is 1-30. If the roughness Ra of one main surface 57a of the heating plate 57 is less than 1.0, it is difficult to uniformly conduct heat through the contact surface with the plate-shaped body 55, so there is a danger of increasing the in-plane temperature difference of the heated surface 55a. More preferably, the surface roughness Ra of one main surface of the heating plate 57 is 3-10.

The heating device 51 of Fig. 5, 6 presses the heating plate 57 by the claw portion 55c of the plate-shaped body 55 and makes the plate-shaped body 55 contact with the heating plate 57 ( FIG. 7 ), instead of directly pressing the heating plate 57 with the claw portion 55c, as shown in FIG. 8 The heating plate 57 is pressed by the spring 59 fixed to the claw portion, so that the main surface 55b of the plate-like body 55 and the main surface 57 of the heating plate 57 can be elastically pressed into contact. By setting a plurality of pressing portions of the springs 59, it is possible to bring the heating plate 57 and the plate-shaped body 55 into contact in a wide range, and thus it is preferable. Therefore, the spring 59 is preferably a member composed of a spring plate having a plurality of fulcrums.

In addition, the plate-shaped ceramic body of the present invention is preferably a ceramic mainly composed of any one of alumina, mullite, and silicon nitride. The above-mentioned ceramics are preferably ceramics with relatively high thermal conductivity, good corrosion resistance, and high insulation resistance under high temperature conditions.

In addition, when the plate-shaped ceramic body is alumina, the alumina content is preferably 80 to 98% by mass. Because such a component can achieve the thermal conductivity of the plate-shaped ceramic body of 16.7-25.21W/(mK), the insulation resistance above 10 ¹³ Ω.cm under the high temperature condition of 300°C, and the bending strength above 300MPa. When the alumina content is less than 90% by mass, sintering aids or impurities such as Mn, Ca, and Si are increased, and therefore there is a risk of lowering insulation resistance under high temperature conditions.

In addition, when the alumina content exceeds 99.5% by mass, there is less sintering aid, and dense sintering becomes difficult at a relatively low temperature of 1700°C or lower, making low-cost mass production difficult.

In addition, the plate-shaped body 5 of the present invention is preferably a conductive metal. The thermal conductivity of the metal reaches more than 200W/(mK), so the heat of the heating plate 7 can be evenly transmitted to the heating surface 55a. Aluminum, iron, or an alloy thereof is preferable as the above-mentioned metal. The thermal expansion coefficient of the plate-shaped body 5 made of metal is preferably 8 to 25×10 ^-6 /°C or less, and the thermal expansion coefficient of the plate-shaped ceramic body 57 is particularly preferably in the range of 8 to 17×10 ^-6 /°C. Due to the difference in thermal expansion between the plate body 55 and the heating plate 57, the distance between the main surface 57a and the main surface 55b becomes uneven, and the heat conduction becomes uneven, so there is a risk that the uniformity of temperature distribution may be impaired. Furthermore, although the object to be heated is in contact with the heating surface 55a and conducts heat from the heating surface 55a to the object to be heated, at this time, because the object to be heated is in contact with the heating surface 55a and slides simultaneously, there is a danger of static electricity on the heating surface 55a. When the heating surface 55a has conductivity, it is preferable because it has the effect of discharging these static electricity.

In addition, the area of the contact surface of the plate-shaped body 55 and the heating plate 57 is 20 to 80% of the area of the heating surface 55a. When it is less than 20%, there is a possibility that the heating surface 55a of the plate-shaped body 55 cannot be uniformly heated. In addition, when the area of the contact surface between the plate-shaped body 55 and the heating plate 57 exceeds 80% of the area of the heating surface 55a, the heating plate 57 becomes larger and the price of the heating device 51 increases, which may be difficult to use industrially. More preferably, the area of the contact surface is 30 to 60% of the area of the heating surface 55a.

In addition, the thickness B of the plate-shaped body 55 is preferably 0.2 to 10 mm. When the thickness is less than 0.2 mm, when the heating plate 57 is fixed by a spring plate, the strength is small, and the plate-shaped body 55 is deformed to produce a gap, and only one side of the contact occurs. Therefore, there is a danger that the temperature difference in the heating surface 55a becomes large. . In addition, when the thickness of the plate-shaped body 55 exceeds 10 mm, the heat capacity becomes large. Even if the heating plate 57 is heated, the temperature of the heating surface 55 a of the plate-shaped body 55 may not be able to rapidly rise in temperature. The thickness B is more preferably 1 to 3 mm.

In addition, the so-called thickness of the heating plate 57 can be represented by an average value of three points in the distance between the main surface 55b and the main surface 55a.

In this way, the plate-shaped body 55 is preferably a member made of metal with a thermal conductivity of 200W/(m.K), and its periphery is equipped with a claw portion 55c in order to contact the heating plate 57. It is preferable to increase the thickness of the peripheral portion, increase the heat capacity, and reduce the heating surface temperature. poor parts.

Next, the manufacturing method and other configurations of the heating device 51 of the present invention will be described.

The heating plate 57 is made of heat-resistant ceramics such as alumina sintered body, mullite sintered body, and silicon nitride-based sintered body. For example, when made of alumina sintered body, alumina (Al ₂ O ₃ ), Silicon (SiO ₂ ), calcium oxide (CaO), magnesium oxide (MgO), etc. are appropriately added and mixed with organic solvents and solvents to form a slurry, and at the same time, use a conventionally known doctor braid or calender The method (calender roll) forms a sheet to obtain a ceramic green sheet. Then, an appropriate punching process is performed on the above-mentioned ceramic green sheet.

The resistance heating element 58 is made of metal materials such as tungsten and molybdenum. The resistance heating element paste obtained by appropriately adding and mixing an organic solvent and a solvent to the metal powder such as tungsten is passed through a conventionally known mesh on a ceramic green sheet formed with a plate-shaped ceramic body in advance. The plate printing method performs printing and coating in a predetermined pattern, and the resistance heating element 8 can be embedded in the plate-shaped ceramic body. Then, the heating plate 57 can be produced by firing the raw material heating plate embedded with the resistance heating element 58 at a high temperature (about 1600° C.). At this time, in order to obtain the above-mentioned surface roughness, it is preferable to adjust the firing temperature and time so that the crystal size on the surface of the heating plate 57 becomes 0.5 to 5 μm as much as possible.

Both ends of the resistance heating element 58 are led out from the end of the heating plate 57, and the two ends of the end are exposed through the opening A provided in the plate-shaped body 57, and the bonding wire 61 is brazed with a brazing material such as solder. The opening A that exposes the two ends of the resistance heating element 58 has the function of forming the brazing joint area between the resistance heating element 58 and the lead wire 61. The ceramic green sheet that has previously become a plate-shaped ceramic body is punched on the heating plate 57 by a punching method. end formed. The above-mentioned opening A further forms a recess 62 on the side wall corresponding to the aperture size of the lead wire 61. When the resistance heating element 58 and the lead wire 61 are soldered on the opening A, if the lead wire 61 can be inserted in the recess 62 formed on the side wall of the opening A , Exposing the upper central portion of the resistance heating element 58 just can correctly join the position, so just can be on the resistance heating element 58 by soldering the bonding wire 61 very firmly by brazing material.

In addition, the lead wire 61 brazed on the resistance heating element 58 on the above-mentioned opening A is made of metal such as nickel. 58 The effect of a certain amount of electricity necessary to produce Joule heat at a specified temperature.

The lead wire 61 utilizes the concave portion 62 provided on the side wall of the opening A in the upper central portion of the exposed resistance heating element 58 to carry out accurate welding, and at the same time, the welding portion is firmly brazed to the resistance heating element by supplying a brazing material 61 such as molten solder. Body 58 on.

Therefore, the heating device 51 of the present invention uses the lead wire 61 to supply a certain power to the resistance heating element 58, so that the resistance heating element 58 emits Joule heat at a certain temperature and functions as a heating element.

In addition, the above-mentioned invention is not limited to the above-mentioned embodiment, and various changes can be made without departing from the gist of the present invention. 61. Fill the opening A with resin or glass to strengthen the joint, or fill the opening A with a heat-resistant material while covering the opening with an insulating plate to strengthen the joint. In this case, the bonding between the resistance heating element 58 and the lead wire 61 becomes stronger, which is preferable. In addition, although the lead wire 61 is bonded to the resistance heating element 58 by using brazing material such as solder in the above-mentioned embodiment, the lead wire 61 can also be bonded by filling the opening A with resin or glass or the like while soldering the lead wire 61 on the resistance heating element 58. The soldering.

The heating device 51 is brought into contact with the metal plate body 55 through silicon lubricating oil. At this time, the thickness of the buffer material between the plate body 55 and the heat conduction member 63 also serving as the ceramic heating plate 57 is preferably 5 to 100 μm. In order to connect the ceramic heating plate 57 and the plate-shaped body 57 used for the hair iron, when the ceramic heating plate 57 and the metal heating plate 57 are directly contacted, warping occurs between the porcelain ceramic heating plate 57 and the metal plate-shaped body 55 or due to heating. The thermal expansion causes deformation, and the joint surfaces cannot be uniformly contacted to form one-sided contact, and point heat conduction occurs, which may increase the temperature difference of the heating surface 55a. The thickness of the buffer material with the heat conduction member 63 is preferably the minimum necessary. On the contrary, if it is too thick, the heat conduction problem of the ceramic heater and the metal plate may deteriorate. The thickness of the heat conduction member 63 is preferably 1 to 100 μm.

In the hair iron according to Embodiment 2 above, the heating plate 57 is provided with a conductor pattern constituting the folded portion of the heating resistor 4 described in Embodiment 1, and the pore occupancy ratio of the ceramic body between any adjacent conductors in the folded portion is preferably: 0.01 to 50% (for example, a heating plate composed of a plate-shaped ceramic heater as shown in FIG. 4 of Embodiment 1 is used). In this case, since the durability of the heating plate 57 can be improved, a more durable hair iron can be provided. Furthermore, the pore occupancy rate of the ceramic body between any adjacent conductors in the folded portion is more preferably 0.1 to 40%, and more preferably 1 to 20%.

Example 1

Prepare a ceramic green sheet with Al ₂ O ₃ as the main component and adjust the total of SiO ₂ , CaO, MgO, and ZrO ₂ within 10% by weight as much as possible, and use a paste composed of W (tungsten) powder binder and solvent to coat the surface The heating resistor 4 and the lead-out part 5 are printed on the top.

In addition, electrode pads 7 are printed on the back surface. The shape of the heating resistor 4 is a pattern that reciprocates four times with a heating length of 5 mm.

Next, in order to fill the space between the conductors with the insulator, the paste containing the insulator is screen-printed. At this time, in order to change the occupancy rate of the pores in the ceramic body between conductors, a material without screen printing and a material in which the paste viscosity was changed and screen printed were prepared.

Next, at the end of the lead-out portion 5 made of W, a through-hole 6 is formed, and paste is injected thereinto to establish conduction between the electrode pad 7 and the lead-out portion 5 . The position of the through hole 6 is formed so as to enter the inner side of the solder joint when performing the solder joint.

Next, the prepared ceramic green sheet was adhered to the periphery of the ceramic molded body, and fired at 1600° C. to form the ceramic heater 1 .

The ceramic heater 1 thus obtained was subjected to continuous energization at 1200° C. for 100 hours to measure the resistance change and evaluate the durability. Evaluation was performed with each group (lot) n=10.

In addition, regarding samples with n=3 in each group, the heating resistor 4 after firing was observed by SEM, and the porosity was measured. The results are shown in Table 1.

(Table 1) Sample No. porosity Hole length heater shape pattern thickness Evaluation results assessment ^* 1 0.005 1/10 cylinder 10 16 x 2 0.01 1/10 cylinder 20 13 ○ 3 0.1 1/10 cylinder 20 10 ○ 4 1 1/10 cylinder 20 8 ◎ 5 10 1/10 cylinder 20 6 ◎ 6 20 1/10 cylinder 20 7 ◎ 7 40 1/10 cylinder 20 11 ○ 8 50 1/10 cylinder 20 14 ○ ^* 9 60 1/10 cylinder 20 17 x 10 10 3/10 cylinder 20 11 ○ 11 10 1/2 cylinder 20 13 ○ 12 10 1/10 Plate 20 8 ◎ 13 10 1/10 cylinder 3 14 ○ 14 10 1/10 cylinder 5 10 ○ 15 10 1/10 cylinder 70 11 ○ 16 50 1/10 cylinder 110 14 ○

The material of each sample is alumina, and the samples marked with * are samples outside the scope of the present invention.

As judged from Table 1, in sample No. 9 having a void occupancy of more than 50% in the ceramic body between conductors and in sample No. 1 having a void occupancy of 0.005%, the resistance value changed by 15% or more, and disconnection occurred. On the other hand, the samples with a void occupancy rate of 50% or less did not have disconnection, indicating good durability.

In addition, as long as the pore occupancy ratio is within the range of the present invention, other factors such as pore length and ink thickness variation have no significance on durability performance.

Example 2

First, in order to obtain a ceramic heating plate as shown in FIG. 9 , on a ceramic green sheet whose main component is Al ₂ O ₃ , the total of SiO ₂ , Cao, MgO, and ZrO ₂ is adjusted as much as possible within 10% by weight. Resistance heating element. The opening A that exposes both ends of the resistance heating element has the function of forming a region where the resistance heating element and the lead wire are brazed, and it is punched by applying a punching method to the ceramic green sheet forming the heating plate in advance, and the end of the heating plate is drilled. form. The above-mentioned opening A further forms a concave portion corresponding to the diameter of the lead wire 61 on the side wall, which is used to solder the lead-out portion of the resistance heating element and the lead wire at the opening A. Then, on the surface of the resistance heating element, a coating layer composed of a ceramic sheet and approximately the same composition is formed, and after being sufficiently dried, the above-mentioned ceramic sheet and a ceramic of approximately the same composition are dispersed, and an adhesive liquid is applied to laminate the prepared ceramic sheet, Firing at 1500-1600°C.

Furthermore, after forming a plating layer made of Ni with a thickness of 3 μm on the surface of the lead-out part of the above-mentioned resistance heating element, a lead wire 61 mainly composed of Ni was bonded at 1030° C. in a reducing atmosphere using brazing material 62 made of Ag. Get a hot plate.

Combining the heating plate obtained by the above method and the plate-shaped body, a hair iron with changes in the thickness, surface roughness (Ra), presence or absence of spring pressing, presence or absence of a heat-conducting member, or material of the heating plate was manufactured.

Next, the temperature distribution on the surface of the heating surface of the manufactured hair iron was measured with a temperature distribution measuring device (TG-6200) made by JEOL Ltd., the maximum temperature and the minimum temperature on the surface of the heating surface were calculated, and the difference between the maximum temperature and the minimum temperature was taken as the temperature Instability was measured.

The results are shown in Table 2.

Table 2 Sample No. Heating plate thickness (mm) Thermal components Surface roughness of heating plate (Ra) pressing spring Heating surface temperature instability (℃) *1 0.3 none 1 none damaged *2 0.3 none 10 none damaged 3 0.5 none 2 none 19 4 0.5 none 2 none 19 5 0.5 Silicone resin 0.5 none 16 6 0.5 Silicone resin 1 none 15 7 0.5 Silicone resin 3 have 13 8 1 Silicone resin 6 have 12 9 1 Silicone resin 10 have 13 10 1 Silicone resin 20 none 14 11 1 Silicone resin 30 none 14 12 3 Silicone resin 40 none 16 13 5 metal particles 3 none 11 14 5 none 3 none 19 15 5 none 3 none 19 *16 7 none 1 none twenty two *17 7 none 10 none twenty four

The evaluation was performed with a plate-shaped body having a thickness of 1.5 mm and a ratio of the plate-shaped body/heating plate contact area to the heating surface area of 70%.

In addition, those marked with * are samples outside the scope of the present invention.

According to the analysis in Table 2, for example, the temperature instability of the heating surface of samples No. 3 to 15 with heating plates whose thickness is 0.5 to 5 mm is below 19°C, showing excellent characteristics.

On the other hand, when the thickness of the heating plate of sample No. 1 and 2 was as thin as 0.3 mm, the heating plate was damaged when the heating plate was mounted on the plate-shaped body. In addition, for samples No. 16 and 17, where the heating plate thickness is 7mm, the temperature instability of the heating surface is as large as 22°C or more, which is not preferable.

In addition, samples Nos. 5 to 13 with heat conduction members between the plate-shaped body and the heating plate are preferable, and the temperature instability of the heating surface is below 16°C, or even smaller.

In addition, sample Nos. 6 to 11 in which the surface roughness of the main surface of the heating plate is 1 to 30 μm are more preferable because the temperature instability of the heating surface is as small as 15° C. or less.

In addition, in Sample Nos. 7 to 9 in which one main surface of the plate-shaped body and one main surface of the heating plate were pressed by a spring, the temperature instability of the heating surface was 13° C. or lower, and it was found that the temperature instability was improved.

Example 3

Next, adjust the content of Al ₂ O ₃ as the main component of the heating plate between 70% and 99.8% to make ceramic sheets, and use these ceramic sheets to make a heating plate according to the method described in Example 2. The high-temperature dielectric strength and flexural strength at 200°C were measured for these materials having different Al ₂ O ₃ compositions. 20 test pieces were produced, and the flexural strength was measured based on the 4-point flexural strength test of JIS standard, and the average value is shown below.

(table 3) Sample No. Alumina content (%) High temperature insulation resistance strength twenty one 70 10 ¹⁰ Ω.cm or more 250Mpa twenty two 75 10 ¹¹ Ω.cm or more 275MPa twenty three 80 10 ¹³ Ω.cm or more 300MPa twenty four 90 10 ¹³ Ω.cm or more 310MPa 25 99.5 10 ¹³ Ω.cm or more 320MPa 26 99.8 10 ¹³ Ω.cm or more 328MPa

According to the analysis in Table 3, the high-temperature insulation resistance of samples No. 23 to 25 with an alumina content of 80 to 99.5% can reach 1×10 ¹³ Ω.cm or more, and even if used as a hair iron, there will be no leakage from the heater power supply. Therefore preferred. In addition, if the bending strength is as high as 300 MPa or more, even if the resistance heating element is heated repeatedly and rapidly, there is little risk of damage due to thermal stress, which is preferable.

However, for samples No. 21 and 22, when the alumina content is as small as 70 or 75% by mass, the insulation resistance is as small as 10 ¹¹ Ω.cm or less under high temperature conditions, and there is a danger of electric leakage when using a heating plate. In addition, the alumina content of sample No. 26 is as high as 99.8% by mass, and it needs to be sintered at a firing temperature above 1700°C, making it difficult to mass-produce at low cost.

Even more preferably, when the alumina content of sample No. 24 and 25 is 90 to 99.5%, the flexural strength is large, which is preferable.

Among them, the alumina content was determined by ICO quantitative analysis of the produced plate-shaped ceramic body.

Example 4

Then, the profile of the plate-shaped body is fixed according to 4mm * 80mm * 20mm (thickness * length * width), and the length of the heating plate is gradually changed, and the hair iron that changes the contact area and the heating area ratio is made in the same manner as in Example 2.

Next, a silicon-based resin is provided as a heat-conducting member between the heating plate and the plate-shaped body, and a rated voltage is applied to the resistance heating element under spring pressure, and the time from room temperature to the saturation temperature at which the maximum temperature of the heating surface is 200° C. is measured as Heating surface saturation time.

The results are shown in Table 4.

(Table 4) Sample No. (plate-shaped object/heating plate contact area/heating area) ratio% Plate Thickness (mm) Heating surface saturation time (sec) 31 5 2 68 32 10 2 63 33 20 3 60 34 30 3 57 35 50 0.1 56 36 50 0.2 50 37 50 1 46 38 50 4 46 39 50 10 47 40 50 12 52 41 60 3 53 42 80 4 60 43 100 4 65

It can be seen from Table 4 that the sample Nos. 33 to 42 with an area ratio of 20 to 80% showed excellent characteristics with a heating surface saturation time as short as 60 seconds or less.

In addition, the sample Nos. 34 to 41 with an area ratio of 30 to 60% had a heating surface saturation time as small as 57 seconds or less, showing more excellent characteristics.

On the other hand, sample Nos. 31 and 32 in which the ratio of the contact area between the heating plate 7 and the plate-shaped body 5 to the heating surface contact area was less than 20% had a saturation time of 63 seconds or more, which was not preferable.

In addition, when the contact area of sample No. 43 exceeds 80%, the heating plate becomes too large, the cost of the heating plate becomes high, and the industrial utility value decreases.

Sample Nos. 36 to 39 having a plate-like body thickness of 0.2 to 10 mm are still more preferable because their heating saturation time is as small as 50 seconds or less.

Claims (20)

1. ceramic heater is characterized in that:

Comprise ceramic body, the conductive pattern that this ceramic body has outer surface and buried underground,

Described conductive pattern is made of conductor, and described conductor is set up according to the mode that formation becomes the return portion of resistance heater, and the emptying aperture occupation rate by the folded ceramic part of the conductor of adjacency in described return portion is 0.01～50%.

2. ceramic heater as claimed in claim 1, wherein:

The length along described outer surface of the emptying aperture that exists between described contiguous conductor is, below 1/2 length of this conductor separation.

3. ceramic heater as claimed in claim 1 or 2, wherein:

The thickness setting of described conductor is at 5～100 mu m ranges.

4. the manufacture method of a ceramic heater, it comprises:

Form the operation of conductor paste by the pattern of regulation on the first ceramic green sheet surface;

With on the face of the formation conductor paste of this first ceramic green sheet, have at least and same thickness of this conductive pattern and second ceramic green sheet more soft, the operation of making the ceramic green sheet duplexer than described first ceramic green sheet by lamination;

Operation with this ceramic green sheet duplexer of bonding on ceramic formation body;

With the ceramic green sheet duplexer that burns till this bonding and the operation of ceramic formation body.

5. the manufacture method of a ceramic heater, it comprises:

Pattern in accordance with regulations forms the operation of conductor paste on the surface of ceramic green sheet;

And fill the operation of insulant between the conductor paste in described predetermined pattern;

And will between this conductor paste, fill the ceramic green sheet of insulant, the face that has formed described conductor paste is bonded in operation on the ceramic formation body as adhesive surface;

With the operation of burning till this bonding ceramic green sheet and ceramic formation body.

6. the manufacture method of ceramic heater as claimed in claim 5 is characterized in that:

The operation of filling described insulant is stuck with paste by screen printing and is carried out.

7. the manufacture method of ceramic heater as claimed in claim 5 is characterized in that:

Filling the operation of described insulant utilizes distributor to carry out.

8. heater is characterized in that possessing:

Heating plate, it is made of the tabular ceramic body of being buried underground resistance heater, has the thickness of 0.5～5.0mm scope; With

Plate body, it has the 1st and the 2nd, at described the 1st described heating plate is set, with described the 2nd as heating surface, this heating surface is made of planar portions and its peripheral chamfered section.

9. heater as claimed in claim 8, wherein:

Between the 1st of described plate body and described heating plate, possesses conducting-heat elements.

10. heater as claimed in claim 9, wherein:

Described conducting-heat elements is to contain the resin that silicon is resin or metal particle.

11. as each described heater in the claim 8～10, wherein:

The surface roughness Ra with described the 1st relative face of described heating plate is 1～30 mu m range.

12. as each described heater in the claim 8～11, wherein:

Has the mechanism of pushing described plate body and described heater.

13. as each described heater in the claim 8～12, wherein:

Described tabular ceramic body with in the middle of aluminium oxide, mullite or the silicon nitride any one as principal component.

14. heater as claimed in claim 13, wherein:

As principal component, the aluminium oxide amount is 80～99.5 quality % to described tabular ceramic body with aluminium oxide.

15. as each described heater in the claim 8～14, wherein:

Described plate body is made of metal.

16. as each described heater in the claim 8～15, wherein:

The area of described plate body and the contacted contact portion of described heating plate be described heating surface area 20～80%.

17. as each described heater in the claim 8～16, wherein:

The thickness of described plate body is 0.2～10.0mm.

18. as each described heater in claim 1～3 and the claim 8～17, wherein:

With hair as heating object.

19. a hair iron, it possesses in the claim 1～3 each described heater in each described ceramic heater or the claim 8～17.

20. a hair iron, it possesses a pair of parts of controlling that switching freely links, and possesses in the claim 1～3 each described heater in each described ceramic heater or the claim 8～17 respectively at described front end of controlling parts.

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