JP4872593B2 - Planar heating element - Google Patents

Description

  The present invention relates to a structure of a planar heating element, particularly in the vicinity of a terminal member for solder bonding.

  In a conventional sheet heating element, as a mode of joining a lead wire to a terminal member of an electrode, a sheet heating element including a terminal member in which solder is previously formed on the electrode, resistor, and the surface to which the lead wire is connected After covering the whole with the exterior material, the exterior material is thermally melted to form an opening, and at the same time, there are those in which the electrode, the terminal member, and the lead wire are joined at the same time (for example, see Patent Documents 1 and 2).

FIG. 8 shows a conventional planar heating element described in the publication. As shown in FIG. 8, a pair of electrodes 2 is disposed on a polyethylene terephthalate film 1, and a resistor 3 having a positive resistance temperature characteristic is disposed on the electrode 2. A terminal member 4 is formed on the power feeding portion of the electrode 2, and the entire substrate 1 on which the electrode 2 and the resistor 4 are formed is formed by an exterior material 6 in which a heat-meltable resin film is laminated on a polyethylene terephthalate film. It is covered. The terminal member 4 is formed with a heat-melting bonding metal 7 made of solder, the lead wire is formed with a heat-melting bonding metal 8, and the bonding metal 7 and the bonding metal are formed in holes penetrating the exterior material 6. 8 of the molten phase is filled, and the terminal member 4 and the lead wire 9 are electrically and physically connected.
JP 2005-149877 A JP-A-2005-302301

  However, in the conventional planar heating element, the exterior material covering the terminal member is removed by heat to secure the opening, and the lead wire and the terminal member are joined. Since the adhesive state between the electrode and the terminal member is likely to vary due to heat generated during the process, high quality control is required.

  Also, for example, when a manufacturing method for forming a planar heating element in a roll shape is adopted, since the solder layer is formed on the terminal member in advance, the terminal member is likely to be thick and difficult to wind in a roll shape. There was a problem.

  The present invention solves the above-described conventional problems, and even when heat is applied to the terminal member and the adhesion state between the electrode and the terminal member may deteriorate, the electrode and the terminal member do not peel off. The object is to provide a planar heating element.

  In order to solve the above-described conventional problems, the planar heating element of the present invention covers a polymer resistor, an electrode, and a terminal member, and in an electrically insulating coating material that is bonded to an electrically insulating substrate, the surface member is previously attached to the terminal member. The disposed conductive resin material is bonded to the electrode, and has an opening at a portion where the lead wire is soldered to the terminal member, and the opening has a size and shape that is inward of the end of the terminal member. And is located eccentrically from the center of the terminal member.

The lead wire is soldered to the outside of the opening by soldering the lead wire through the opening at a position that is inward of the end of the terminal member and is eccentric from the center of the terminal member. Therefore, it is easy to ensure the adhesive state between the electrode and the terminal member at the end portion on the side far from the opening, and the end portion around the terminal member is planar on the electrically insulating coating material. Therefore, the terminal member is prevented from peeling off from the electrode.

  According to the planar heating element of the present invention, the adhesion state between the electrode and the terminal member can be ensured satisfactorily, the terminal member can be prevented from being peeled off, and a stable power feeding state can be provided.

  In a first aspect of the present invention, an electrode and a polymer resistor that generates heat by applying a voltage by the electrode are formed on an electrically insulating substrate, and a terminal member that can be soldered is bonded to the electrode. In a planar heating element made of an electrically insulating covering material that covers a polymer resistor, an electrode, and a terminal member and is bonded to the electrically insulating substrate, the electrically insulating covering material solders a lead wire to the terminal member An opening is provided at a portion to be joined, and the opening has a size and shape that is inward of the end of the terminal member, and is eccentric from the center of the terminal member. Thereby, by soldering the lead wire through the opening having a size and shape that is inward from the end of the terminal member and eccentric from the center of the terminal member, Since the solder does not get wet outside the opening, the end on the side far from the opening is easily secured, and the end around the terminal member is covered with an electrically insulating coating. Therefore, it can prevent that the said terminal member peels from the said electrode.

  In the second invention, the opening has a size that does not exceed a half of the surface that the terminal member desires for the electrically insulating coating material. Thereby, since the solder does not get wet outside the opening, the area affected by the heat of the solder joint can be reduced, and the area securing the adhesion state can be increased more than the first invention. it can.

  In the third aspect of the invention, the opening is positioned so as not to hang over the center of the terminal member. Thereby, since the solder joint position has shifted | deviated from the center, the adhesion state beyond the center part of a terminal member is securable.

  In the fourth invention, the shape of the opening is circular or elliptical. As a result, since there are no corners in the opening, even when the terminal member is subjected to a tensile stress in the peeling direction or the like, stress is less concentrated at one location of the terminal portion than in the rectangular shape. It is possible to prevent the opening from cracking or breaking.

  In the fifth aspect of the invention, a conductive resin material and an adhesive material are juxtaposed on the surface of the terminal member to be joined to the electrode. The conductive resin material is responsible for a strong physical connection as well as an electrical connection with the electrode, and the adhesive material has a function of temporarily fixing until the terminal member is completely fixed by the exterior material by the adhesive force. . Since the terminal member can be temporarily fixed, it is possible to easily fix the terminal member at a predetermined position of the electrode until the terminal member is covered with the exterior material and physically fixed.

  In the sixth invention, the conductive resin material is disposed on the terminal member on the surface to be joined to the electrode, and the adhesive material is disposed more in the vicinity immediately below the opening than the portion having no opening. It is. The adhesive material has the function of temporarily fixing the terminal member by the exterior material due to its adhesive strength, but compared with the bonding strength between the conductive resin material and the electrode after heat welding and thermosetting And the adhesive strength is weak. Therefore, the terminal member can be temporarily fixed by disposing a large amount of adhesive material immediately below the opening, and disposing less adhesive material at positions other than directly below the opening than directly below the opening. It becomes the structure which can raise the adhesive strength between an electrode.

(Embodiment 1)
1 to 2 are schematic configuration diagrams of a planar heating element according to Embodiment 1 of the present invention. In particular, FIG. 1 is a plan view, and FIG. 2 is an XY sectional view in the vicinity of a terminal portion in FIG. .

  In FIG. 1, a planar heating element 1 overlaps a pair of electrodes 3 formed by printing and drying a silver paste on a relatively elastic electrically insulating base material 2 such as polyethylene terephthalate and the like. A polymer resistor 4 formed by printing and drying polymer resistor ink is formed. And thin-walled electric insulation such as polyethylene terephthalate in which an adhesive resin layer 10 such as a copolyester adhesive having adhesiveness with the electrode 3, the polymer resistor 4, and the electric insulating substrate 2 is formed in advance. An electrically insulating coating material 9 laminated with a conductive overcoat material is bonded together.

  The electrode 3 is provided with wide main electrodes 3a and 3b so as to be opposed to each other, and a plurality of comb-shaped branch electrodes 3c and 3d are alternately provided from the main electrodes 3a and 3b, and overlap each other. By supplying power from the branch electrodes 3c and 3d to the polymer resistor 4 arranged as described above, a current flows through the polymer resistor 4 to generate heat. This polymer resistor 4 has PTC characteristics, and when the temperature rises, the resistance value of the polymer resistor 4 rises and has a self-temperature adjusting function so as to reach a predetermined temperature, so temperature control is unnecessary. Thus, it has a function as the highly safe planar heating element 1. Since the sheet heating element 1 having this type of PTC characteristic generally requires a large inrush current in order to obtain rapid thermal performance, a large current flows through the terminal member 5 that is a power feeding section.

  A conductive resin material 5b is formed on the surface of the terminal member 5 that is in contact with the power feeding portion of the electrode 3, and the conductive resin material 5b is thermally adhesive to the electrode 3 and is thermosetting. A conductive paste prepared by dispersing silver powder as a conductivity-imparting material in polymerized polyester and adding an appropriate amount of isocyanate as a curing agent is used. The conductive resin material 17a at this stage retains thermoplasticity because it is dried at a low temperature so as not to cause a curing reaction due to isocyanate. If the pressure is applied while heating to the isocyanate curing reaction temperature or higher, the electrode 3 is thermally fused, and the electrode 3 and the terminal member 5 are electrically and physically joined by the conductive resin material 5b. The Rukoto. In this case, in particular, when the same kind of resin and the same kind of metal powder as the conductive resin material 5b are used for the electrode 3, the heat fusion property is extremely good, and sufficient heat fusion strength and low contact resistance can be obtained.

  Here, as an order of processing steps, first, a pair of electrodes 3 is formed by printing and drying a silver paste on an electrically insulating base material 2 such as polyethylene terephthalate prepared in a roll shape. Next, the polymer resistor 4 is formed by printing and drying the polymer resistor ink so as to overlap the electrode 3, and the polymer resistor 4 and the electrode 3 on the electrically insulating substrate 2 and the electrode 3 are fed. The terminal member 5 to be temporarily placed on the electrode 3 and the electrically insulating coating material 9 are covered with the adhesive resin layer 10 and then the conductive resin material 5b of the terminal member 5 and the electrode 3 are electrically conductive resin. After heat welding with the thermosetting reaction of the material 5 b, the opening 7 is formed in the electrically insulating coating material 9 at a position eccentric from the center by a laser or the like to expose the terminal member 5, and then the lead wire is opened at the opening 7. 8 is connected to the terminal member 5 by welding or the like, and an insulating protective material 11 such as hot melt is applied to the vicinity of the opening 7 and the attachment portion of the lead wire 8.

  In this way, the terminal member 5 is electrically insulated from the insulating base material 2 and the electrically insulating covering material 9 by simultaneously performing the process of attaching the electrically insulating covering material 9 and the step of temporarily placing the terminal member 5 on the electrode 3. The next process can be performed without being moved or peeled.

Since the terminal member 5 is sandwiched between the electrically insulating base material 2, the electrode 3 and the electrically insulating coating material 9 and integrated with the adhesive resin layer 10, the terminal member 5 is disposed between the terminal member 5 and the electrode 3. Therefore, it is possible to realize a highly safe configuration conforming to the Electrical Appliance and Material Safety Law.

  As a method of thermally welding the terminal member 5 together with the thermosetting reaction, there are a method of applying heat from the outside to the entire vicinity of the terminal with a hot plate, a method of heating only the highly conductive terminal member by induction heating, high frequency welding or the like.

  When heating from the outside, the terminal member 5 is sandwiched between the electrically insulating substrate 2, the electrode 3, and the electrically insulating coating material 9, so that the heat is passed through the electrically insulating substrate 2 or the electrically insulating coating material 9. The plate is pressed and heated. Further, when, for example, polyethylene terephthalate is used for the electrically insulating base material 2 or the electrically insulating coating material 9, the heat shrinkage start temperature starts from about 180 ° C., and the isocyanate curing reaction temperature of the conductive resin material 5b starts from about 150 ° C. To do. The conductive resin material 5b is completely thermally cured and thermally welded, and the electrical insulating base material 2 and the electrical insulating coating material 9 are electrically insulative as conditions that do not cause the heat shrinkage and the deformation caused by the heat shrinkage to a certain extent. Although it depends on the thickness of each of the substrate 2, the electrode 3, the terminal member 5, the electrically insulating covering material 9, and the adhesive resin layer 10, the hot plate temperature is set to about 150 ° C. to 250 ° C. for about 5 seconds to 30 minutes. It is necessary to crimp.

  There is also a method of directly heating the terminal member 5 by induction heating or high frequency welding. For example, when performing induction heating, a magnetic material such as iron is used for the terminal member 5, or if a high-frequency current can be generated, a non-magnetic material such as copper but a relatively high conductivity is used. If a magnetic field generated by an alternating current is applied to the terminal member 5, only the terminal member 5 can be heated.

  Heat is transmitted only to the terminal member 5 and the electrically insulating base material 2 and the electrically insulating coating material 9 in the immediate vicinity of the terminal member 5, and the thermal contraction of the electrically insulating base material 2 and the electrically insulating coating material 9 is suppressed. Therefore, a good adhesion state can be easily formed between the conductive resin material 5b and the electrode 3. In addition, in the case of the induction heating method, since only the terminal member 5 is heated, the temperature rise is very fast, and it is possible to reach the isocyanate curing reaction temperature of the conductive resin material 5b in a short time, contributing to the improvement of productivity. Will be.

  Furthermore, since the insulating protective material 11 such as hot melt is applied to the attachment portion of the terminal member 5 and the lead wire 8, power is supplied from the attachment portion of the opening 7 and the lead wire 8 by the electrode 3 and the electrode 3. The polymer resistor 4 is protected by the insulating protective material 11 and is configured to be cut off from the outside air, thereby preventing problems such as contamination deterioration due to moisture and foreign matter and short-circuiting due to migration of the electrode 3. The stability and durability of performance can be improved. In addition, when the insulating protective material 11 is applied, the lead wire 8 is pulled out in a direction different from the direction in which force may be applied to the product, so that the terminal can be applied even when force is applied to the product. No force is directly applied to the member 5, and peeling between the terminal member 5 and the electrode 3 can be suppressed.

  In addition, the material of the electrode 3 that can be printed is hardly connectable with the solder 6, but the terminal member 5 and the electrode 3 can be surface-bonded through the conductive resin material 5b, and the terminal member 5 can be soldered. 6 connections are possible. And according to the above-mentioned connection method, since the conductive resin material 5b can be formed into a thin surface, the junction resistance value can be made extremely low, so that a large current can flow, and the surface By joining, sufficient strength can be secured.

Therefore, it is possible to draw a complicated electrode 3 pattern and excellent flexibility, but the lead wire 8 is formed by the solder 6 even if the electrode 3 is formed by printing in which the solder 6 connection is often impossible. It is possible, and it is extremely excellent in productivity, and at the same time it is an extremely strong electrical and physical bond, withstands high currents, and is highly reliable. Furthermore, it is extremely useful when a large amount of current is required because the power supply voltage is low, or when a heating element having a positive resistance temperature characteristic that requires a large inrush current to obtain rapid thermal performance is used. is there.

  Further, in a simple quality control situation, the solder 6 spreads only in the opening portion 7 with good wettability and is covered with the electrically insulating coating material 9 so that it does not protrude outside the opening portion 7 with poor wettability. .

  The electrically insulating base material 2, the electrically insulating coating material 9, the terminal member 5, and the electrode 3 are thermally expanded and contracted at different temperature coefficients and thermally welded to the terminal member 5 due to heat when the solder 6 is disposed. The adhesive strength between the electrode 3 and the electrode 3 may be reduced. In particular, when a resin material such as polyethylene terephthalate is used for the electrically insulating base material 2 and the electrically insulating covering material 9 as in the present embodiment, the terminal member 5a, which is a metal, the electrically insulating base material 2, and the electrically insulating material The coefficient of thermal expansion with the conductive covering material 9 is greatly different and an internal stress is applied, so that the adhesive strength between the terminal member 5 around the solder 6 and the electrode 3 may be reduced. However, since the opening 7 is located eccentrically from the center of the terminal member 5 from the center, the thermal effect due to the operation of the solder 6 extends to the periphery of the opening 7, and the conductive resin material 5b on the side far from the opening 7 The electrode 3 is not affected by the heat of the solder 6, and a sufficient planar adhesive strength can be maintained.

  Further, when performing the solder 6, a soaking plate made of a material having high thermal conductivity such as aluminum is placed under the electrically insulating base 2 so that heat is applied only near the solder 6. On the insulating covering material 9, the vicinity of the terminal member 5 is covered to such an extent that the solder workability is not lowered, and high adhesion is provided between the heat equalizing plate placed underneath and the electrically insulating base material 2. By performing the soldering operation, it is possible to further reduce the thermal effect of the solder 6 on the bonding state between the terminal member 5 and the electrode 3.

(Embodiment 2)
The second embodiment is different from the first embodiment in the area of the opening 7, and will be described with reference to the same drawing as the first embodiment.

  That is, the opening 7 has a size that does not exceed one half of the surface desired for the electrically insulating coating material 9 of the terminal member 5 at a position eccentric from the center.

  By setting the opening 7 to a size that does not exceed one half of the surface desired for the electrically insulating coating material 9 of the terminal member 5, the spread of the solder 6 can be reduced to the surface desired for the electrically insulating coating material 9 of the terminal member 5. The size of the conductive resin material 5b that is affected by the heat of the solder 6 is smaller than that of the first embodiment, and the adhesion state of the conductive resin material 5b is stably ensured. As a result, the area is increased, a highly reliable terminal configuration can be provided as compared with the first embodiment, and management of positional accuracy when the opening 7 is formed by a removing means such as a laser is simplified. be able to.

  When the terminal member 5 has a substantially rectangular shape of 10 mm × 20 mm, the size of the opening 7 is, for example, a square having a side of about 6 mm, and the soldering tip temperature is about 370 ° C. Ensuring adhesion of the conductive resin material 5b can be realized at the same time.

(Embodiment 3)
3 to 4 are schematic configuration diagrams of the planar heating element according to the third embodiment of the present invention. In particular, FIG. 3 is a plan view, and FIG. 4 is an XY sectional view in the vicinity of the terminal portion in FIG. .

  3 to 4, the third embodiment is different from the second embodiment in the position of the opening 7, and the same parts are denoted by the same reference numerals and only different parts will be described.

That is, the opening 7 is at a position that is greatly decentered from the center, has a size that does not exceed one half of the desired surface of the electrically insulating coating material 9 of the terminal member 5, and the opening 7 does not hang on the center of the terminal member. It is a position. Thereby, since the solder joint position has shifted | deviated from the center, the adhesion state beyond the center part of a terminal member is securable.

  As the area of the terminal member 5 is increased, the bonding strength between the terminal member 5 and the electrode 3 is increased and the reliability of the bonding is increased. At the same time, the area of the electrode 3 in the portion where the terminal member 5 is attached is also increased. There is a need. This is contrary to the original purpose of the product, which is to provide the maximum area of the polymer resistor 4 in the limited product area, increase the heat generation area, and uniformly warm the entire product. Therefore, the opening 7 is set to a position that is greatly decentered from the center, is set to a size that does not exceed one half of the surface desired for the electrically insulating coating material 9 of the terminal member 5, and the position where the opening 7 does not cover the center of the terminal member By doing so, the part that feeds power to the terminal member 5 by the lead wire 8 in the limited area of the terminal member 5 and the part that feeds power from the terminal member 5 to the electrode 3 with a good adhesion state are clearly separated for quality control. By doing so, it is possible to minimize the area of the terminal member 5 and provide a highly reliable power feeding method with simple production management. Specifically, as a method for managing the adhesion state between the terminal member 5 and the electrode 3, it is only necessary to manage the adhesion state on the side of the terminal member 5 that does not constitute the opening 7. It becomes simple.

  For example, the shape of the terminal member 5 is a substantially rectangular shape such as 10 mm × 20 mm, the opening 7 is a square having a side of about 6 mm, and the center of the opening is at a position 5 mm from the end in the longitudinal direction of the terminal member 5. In this way, the structure does not reach the center of the terminal member 5, the soldering tip temperature is about 370 ° C., and the solder 6 is formed, so that the bonding state between the terminal member 5 and the electrode 3 in the vicinity of the opening 7 becomes unstable. The part to be obtained can be limited to only a half on the side where the opening 7 of the terminal member 5 is formed.

(Embodiment 4)
FIG. 5 shows a schematic plan view of a planar heating element in Embodiment 4 of the present invention. A sectional view in the vicinity of the terminal portion is the same as that in FIG.

  In FIG. 5, the fourth embodiment is different from the first to third embodiments in the shape of the opening 7, and the same portions are denoted by the same numbers and only different portions are described.

  By making the shape of the opening 7 a circle or an ellipse, the spread of the solder 6 is made uniform, and the solder 6 itself also becomes a circle or an ellipse, and the electrically insulating substrate 2 that occurs when the solder 6 is attached. In addition, each of the electrical insulating covering material 9, the terminal member 5, and the electrode 3 can perform stress dispersion by thermal expansion / contraction. After the planar heating element is completed, if the shape of the opening 7 is circular or oval, it is possible that the force tends to concentrate particularly when a force is directly applied to the terminal member 5 by pulling with the lead wire 8. 7 can be relaxed, and the reliability with respect to the tension by the lead wire 8 can be further improved.

(Embodiment 5)
6 is an XY cross-sectional view in the vicinity of the terminal portion of the plan view of the schematic configuration diagram of the planar heating element shown in the first embodiment of the present invention in the fifth embodiment, and FIG. 7 shows the embodiment. It is the top view which looked at the terminal member 5 in 5 from the side joined with an electrode.

  6 and 7, the fifth embodiment is different from the first to fourth embodiments in that an adhesive material 5c is disposed on the surface of the terminal member 5 that contacts the electrode 3 on the conductive resin material 5b. Thus, the same parts are given the same numbers and only different parts will be described.

A conductive resin material 5b is formed on the surface of the terminal member 5 in contact with the power feeding portion of the electrode 3 by printing or the like, dried at a temperature at which the isocyanate curing agent does not react, and then adhered to the conductive resin material 5b. The conductive material 5c is partially formed by printing or the like.

  For example, in FIG. 7, 24 adhesive materials 5 c having a thickness of about 30 μm are arranged on the conductive resin material 5 b of the substantially rectangular terminal member 5 such as 10 mm × 20 mm in a diameter of 1 mm. By adopting the configuration shown in FIG. 7, in the step of thermally welding the terminal member 5 together with the thermosetting reaction, the pressure-sensitive adhesive material 5c for temporary bonding is thinned by heat and pressure by applying a pressure of a certain level or more. The material 5 itself is also partially deformed, so that the conductive resin material 5b and the electrode 3 can be joined at a portion without the adhesive material 5c.

  The conductive resin material 5b is responsible for strong physical connection as well as electrical connection with the electrode 3, and the adhesive material 5c performs temporary fixing until the terminal member is completely fixed by the exterior material by the adhesive force. Has function. By temporarily fixing the terminal member 5, it is possible to easily fix the terminal member 5 at a predetermined position of the electrode 3 until the terminal member 5 is covered with the electrically insulating coating material 9 and physically fixed. To. Due to the temporary fixing with the adhesive material 5c, the terminal member 5 is not displaced from the predetermined position of the electrode 3 when the electrically insulating covering material 9 is covered with the insulating base material 2, and stable positioning accuracy with simple production management. Can be obtained. Further, the terminal member 5 can be attached to a release paper or the like by temporary fixing with the adhesive material 5c, and the terminal member 5 can be easily manufactured and stored.

  By adopting the configuration of the fifth embodiment, it is possible to configure the terminal member 5 that can perform temporary bonding while securing a sufficient bonding area between the conductive resin material 5 b and the electrode 3.

  In the present embodiment, 24 adhesive materials 5c having a diameter of 1 mm are arranged in 24 pieces and the thickness is assumed to be 30 μm. However, the arrangement, area, and thickness of the adhesive material 5c are within a range that achieves the object of the present invention. The configuration may be anything.

(Embodiment 6)
FIG. 7 is an XY cross-sectional view of the vicinity of the terminal portion in the plan view of the schematic configuration diagram of the planar heating element shown in the first embodiment of the present invention in the fifth embodiment, and FIG. 8 shows the embodiment. It is the top view which looked at the terminal member 5 in 5 from the side joined with an electrode.

  7 and 8, the sixth embodiment is different from the fifth embodiment in the arrangement pattern of the adhesive material 5c on the surface of the terminal member 5 that contacts the electrode 3 on the conductive resin material 5b. The parts are given the same numbers and only different parts are described.

  For example, in FIGS. 7 and 8, an adhesive material 5c having a thickness of about 30 μm is formed on the conductive resin material 5b of the substantially rectangular terminal member 5 such as 10 mm × 20 mm on the side where the diameter of 1 mm and the opening 7 is not provided. They are arranged.

  The bonding strength between the conductive resin material 5b after heat welding and thermosetting and the electrode 3 is higher than the adhesive strength of the adhesive material 5c. In the portion where the adhesive material 5c is disposed, the conductive resin material 5b is not exposed to the electrode 3, and the conductive resin material 5b and the electrode 3 may be welded even after thermal welding and thermal curing. As a result, strong adhesive strength cannot be obtained.

However, the bonding strength between the conductive resin material 5b immediately below the opening 7 and the electrode 3 is such that when the solder 6 is disposed to bond the lead wire 8 to the terminal member 5, the heat is electrically insulated. Since the conductive substrate 2, the electrically insulating covering material 9, the terminal member 5, and the electrode 3 are thermally expanded and contracted at different temperature coefficients, the adhesive strength between the thermally welded terminal member 5 and the electrode 3 is small. May be. Therefore, in the present invention, the bonding strength between the conductive resin material 5b immediately below the opening 7 and the electrode 3 is finally reduced, and a large amount of the adhesive material 5c is provided in the vicinity immediately below the opening 7. It is arranged. As a result, the terminal member 5 has a function of the terminal member 5 immediately below the opening 7 serving as a place responsible for temporary bonding with the electrode 3 and connection with the lead wire 8, and is separated from the opening 7 in the terminal member 5. It becomes the structure which performs the physical joining and electrical connection between the conductive resin material 5b and the electrode 3 in the location.

  In the present embodiment, twelve adhesive materials 5c having a diameter of 1 mm are disposed on the side where the opening 7 is disposed, and the thickness is assumed to be 30 μm. However, the arrangement, area, and thickness of the adhesive material 5c are not limited to the present invention. Any configuration may be used as long as the object is achieved. For example, it is good also as a structure which covers the adhesive material 5c over the whole directly under the location which provides the opening part 7. FIG.

  In the first embodiment, the description has been given of the processing step in which the electrode 3 and the polymer resistor 4 fed by the electrode 3 are printed on the roll-shaped electrically insulating substrate 2. A processing step in which the electrode 3 and the polymer resistor 4 fed by the electrode 3 are printed or extruded on the insulating substrate 2 may be used. In addition, the configuration, material, and construction method of each part also achieve the object of the present invention. So long as the configuration is arbitrary.

  Moreover, although the substantially rectangular shape was assumed as a shape of the terminal member 5, as long as it is a shape which does not impair the effect of this invention, it may be what kind of shape. In particular, for example, in the vicinity of the center of the surface of the terminal member 5 that is desired for the electrically insulating covering material, it is narrower than the portion having the opening, or a central portion such as a shape provided with a plurality of through holes. By adopting a shape that deteriorates the heat conduction at, the thermal effect of the solder 6 can be further alleviated, and the present invention can be more effectively carried out.

  Further, in this embodiment, the insulating protective material 11 is applied, but it may be omitted if the conditions are such that insulation can be ensured.

  As described above, the planar heating element according to the present invention is useful even when tension is applied to the lead wire because the adhesion state between the electrode and the terminal member is ensured and the terminal member can be prevented from peeling off.

Schematic diagram of the planar heating element in the first and second embodiments XY cross-sectional schematic diagram of the terminal part vicinity of FIG. 1 in Embodiment 1,2. Schematic diagram of the planar heating element in the third embodiment XY cross-sectional schematic diagram of the terminal part vicinity of FIG. 3 in Embodiment 3. FIG. Schematic diagram of planar heating element according to Embodiment 4 XY cross-sectional schematic diagram of the terminal part vicinity of FIG. 1 in Embodiment 5. FIG. The schematic diagram which looked at the terminal member in Embodiment 5 from the side joined with an electrode The schematic diagram which looked at the terminal member in Embodiment 6 from the side joined with an electrode (A) Plan view showing the configuration of a conventional heating element (b) Cross-sectional view of the heating element terminal portion

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar heating element 2 Insulating base material 3 Electrode 4 Polymer resistor 5 Terminal member 6 Solder 7 Opening 8 Lead wire 9 Electrical insulating coating material 10 Adhesive resin layer 11 Insulating protective material

Claims (6)

On the electrically insulating substrate, an electrode and a polymer resistor that generates heat by applying a voltage by the electrode are formed, and a conductive resin material is disposed on a terminal member of a surface joined to the electrode. In a sheet heating element comprising an electrically insulating coating material that is bonded to a terminal member capable of soldering bonding, covers the polymer resistor, electrode, and terminal member, and is bonded to the electrically insulating base material. The conductive covering material has an opening at a portion where the lead wire is soldered to the terminal member, and the opening is inwardly sized and shaped with respect to the end of the terminal member, and the terminal member A planar heating element located eccentric from the center. The planar heating element according to claim 1, wherein the opening has a size that does not exceed a half of a surface that the terminal member desires for the electrically insulating coating material. The planar heating element according to claim 2, wherein the opening is located at a position that does not hang over the center of the surface desired for the electrically insulating coating material of the terminal member. The planar heating element according to any one of claims 1 to 3, wherein the shape of the opening is circular or elliptical. The heating element according to any one of claims 1 to 4, wherein a conductive resin material and an adhesive material are juxtaposed on a terminal member on a surface joined to the electrode. The conductive resin material is disposed on the terminal member on the surface to be joined to the electrode, and more adhesive material is disposed in the vicinity immediately below the opening than at the portion having no opening. The heating element according to any one of the above.