JP7035812B2 - Heater device - Google Patents

Description

The present invention relates to a heater device.

Conventionally, in a heater device that heats an object by releasing radiant heat when the heat generating part generates heat, whether or not an object such as a finger approaches or comes into contact with the heat generating part is determined by the capacitance of the electrode provided in the heater device. A technique for determining based on the above is described in Patent Document 1. This reduces the possibility that the object will come into contact with the heat generating portion and be overheated. Hereinafter, such a determination is referred to as an object determination.

Japanese Unexamined Patent Publication No. 2014-190674

The inventor has studied in such a heater device to perform object determination based on the capacitance at a predetermined reference time point and the current capacitance after energization of the heat generating portion.

As a result of the examination, the inventor conceived that there may be a situation where the object is already sufficiently close to or in contact with the heat generating portion at the above reference time point, or the electrode is broken. In such a case, the inventor has noticed that the capacitance at the reference point in time is not appropriate, and the object determination using such capacitance becomes inaccurate. If the object determination using the capacitance becomes inaccurate, the object may come into contact with the heat generating portion and be excessively heated.

In view of the above points, the present invention may cause inaccurate object determination in a heater device in a situation where an object is already sufficiently close to or in contact with a heat generating portion at a reference time point, or an electrode is broken. The first purpose is to reduce the sex.

Further, the inventor has studied in such a heater device to perform object determination based on the capacitance at a reference time point and the current capacitance after energization of the heat generating portion.

As a result of the examination, the inventor conceived that there may be a situation where the object is already sufficiently close to or in contact with the heat generating portion at the above reference time point, or the electrode is broken. In such a case, the inventor has noticed that the capacitance at the reference point in time is not appropriate, and the object determination using such capacitance becomes inaccurate.

In view of the above points, the present invention is inaccurate in determining an object in a heater device in a situation where an object is already sufficiently close to or in contact with the heat generating portion before the heat generating portion is energized, or the electrode is disconnected. The first purpose is to reduce the possibility of becoming.

Further, as a result of another study, the inventor found that when energization of the heat generating portion started after the above reference time point, the temperature of the heat generating portion increased, and as a result, the capacitance of the electrode increased due to the deformation of the heater device. I came up with the idea that it may change. In such a case, there is a possibility that the current capacitance deviates significantly from the capacitance at the reference time even though an object other than the heater device is neither in contact with the electrode nor sufficiently close to it. There is. In this case, the inventor has noticed that the object determination using the capacitance becomes inaccurate.

In view of the above points, a second object of the present invention is to reduce the possibility that the object determination becomes inaccurate due to the deformation of the heater device after energizing the heat generating portion in the heater device.

The invention according to claim 1 for achieving the first object is a heater device, which is a heating unit (22) that generates heat by energization, an electrode (24) to which a voltage is applied, and the heat generating unit. A control unit (40) for controlling energization to the electrode is provided, and the control unit has a reference capacitance (C1), which is the capacitance of the electrode at a reference time point (t1), within a predetermined range (Cm). When the range determination unit (S110) for determining whether or not the electrode is present and the range determination unit determines that the reference capacitance is within the predetermined range, the electrode is static at a time point after the reference time point. It has a normal operating unit (S115-S130) for determining whether or not to reduce the amount of electricity supplied to the heat generating portion based on the electric capacity (C) and the reference capacitance, and the range determining unit. Is a heater device that prohibits the operation of the normal operating unit when it is determined that the reference capacitance is not within the predetermined range.

As described above, when it is determined that the reference capacitance (C1) at the reference time point before the heat generating portion is energized is not within the predetermined range (Cm), the operation of the normal operating portion is prohibited. Therefore, in a situation where the object is already sufficiently close to or in contact with the heat generating portion at the reference time point, or the electrode is disconnected, the possibility that the object determination becomes inaccurate in the normally operating portion is reduced.

The invention according to claim 5 for achieving the second object controls energization of a heat generating portion (22) that generates heat by energization, an electrode (24) to which a voltage is applied, and the heat generating portion. The control unit includes a control unit (40), and the control unit to a specific unit (S105) that specifies a reference capacitance (C1), which is the capacitance of the electrode at a reference time point (t1), and a heat generation unit. Calculation to calculate the correction value (P) for reducing the absolute value of the difference between the capacitance (Cx) of the electrode and the reference capacitance at the correction time point (t6) after the energization of The amount of electricity supplied to the heat generating portion is reduced based on the unit (S225), the capacitance (C) of the electrode at the time point (t7) after the correction time, the reference capacitance, and the correction value. It is a heater device provided with a normal operating unit (S115-S130) for determining whether or not to perform the operation.

In this way, the correction value (P) for reducing the absolute value of the difference between the electrostatic capacitance (Cx) of the electrode and the reference capacitance at the correction time point (t6) after the energization of the heat generating portion is started. Is used to determine whether or not to reduce the amount of electricity supplied to the heat generating portion at a time point (t7) after the correction time point. By doing so, the correction value P corresponding to the deformation of the heater device due to the temperature rise can be applied to the object determination at a later time point. As a result, it is possible to reduce the influence of the deformation of the heater device on the object determination after energizing the heat generating portion. Therefore, it is possible to reduce the possibility that the object determination becomes inaccurate due to the deformation of the heater device after energizing the heat generating portion.

The reference numerals in parentheses attached to each component or the like indicate an example of the correspondence between the component or the like and the specific component or the like described in the embodiment described later.

It is a figure which shows the arrangement of the heater apparatus of 1st Embodiment. It is a schematic diagram of a heater device. FIG. 2 is a cross-sectional view taken along the line III-III of FIG. It is a block diagram of a heater device. It is a flowchart of the process executed by a control unit. It is a schematic diagram which shows the electric field generated in a heater device. It is a figure which shows the electric field when an object approaches an electrode. It is a graph which shows the time-dependent change of the capacitance detected by the detection part. It is a figure which shows the situation which the electrode is broken. It is a flowchart of the process executed by the control unit in 2nd Embodiment. It is a flowchart of the process additionally executed by the control unit in 2nd Embodiment. It is a graph which shows the time-dependent change of temperature and capacitance. It is sectional drawing before the change of the distance between a transmitting electrode and a receiving electrode. It is sectional drawing after the change of the distance between a transmitting electrode and a receiving electrode. It is a flowchart of the process additionally executed by the control unit in 3rd Embodiment. It is a flowchart of the process additionally executed by the control unit in 4th Embodiment.

Hereinafter, a plurality of embodiments will be described with reference to the drawings. In each of the following embodiments, the parts that are the same or equal to each other are designated by the same reference numerals in the drawings.

(First Embodiment)
First, the first embodiment will be described. In FIG. 1, the heater device 20 according to the first embodiment is installed in the room of a moving body such as a road traveling vehicle, a ship, or an aircraft. The heater device 20 constitutes a part of the heating device for the room. The heater device 20 is an electric heater that generates heat by being supplied with power from a power source such as a battery or a generator mounted on a moving body. The heater device 20 is formed in the shape of a thin plate. The heater device 20 generates heat when electric power is supplied. The heater device 20 radiates radiant heat H mainly in the direction perpendicular to the surface in order to heat the object positioned in the direction perpendicular to the surface thereof.

A seat 11 for the occupant 12 to sit in is installed in the room. The heater device 20 is installed indoors so as to radiate radiant heat H to the feet of the occupant 12. The heater device 20 can be used, for example, as a device for immediately providing warmth to the occupant 12 immediately after the start of another heating device. The heater device 20 is installed on the wall surface of the room. The heater device 20 is installed so as to face the occupant 12 in the assumed normal posture. For example, a road vehicle has a steering column 14 for supporting the steering wheel 13. The heater device 20 can be installed on the lower surface of the steering column 14 so as to face the occupant 12.

Next, the configuration of the heater device 20 will be described with reference to FIGS. 2, 3, and 4. In FIGS. 2 and 3, the heater device 20 extends along an XY plane defined by axes X and Y. The heater device 20 has a thickness in the direction of the axis Z. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The heater device 20 is formed in a substantially quadrangular thin plate shape. The heater device 20 includes a heat generating portion side low heat conducting portion 21, a heating layer 220, an insulating substrate 23, an electrode 24, and an electrode side low heat conducting portion 25. The heat generating portion side low heat conducting portion 21, the heating layer 220, the insulating substrate 23, the electrode 24, and the electrode side low heat conducting portion 25 constitute a heater main body portion. The heater device 20 can also be referred to as a planar heater that radiates radiant heat H mainly in a direction perpendicular to the surface.

The heat generating layer 220 has a plurality of heat generating portions 22 and two energizing portions 26 that generate heat by energization. The heat generating layer 220 is arranged on the back surface side (that is, the anti-human body side) of the insulating substrate 23. That is, each heat generating portion 22 and each energizing portion 26 are formed on the back surface side of the insulating substrate 23.

The heat generating portions 22 form a rectangle extending in the direction of the axis Y, and are arranged side by side in the axis X direction apart from each other. The heat generating portions 22 are connected to each other via the energizing portion 26. The plurality of heat generating portions 22 are regularly arranged so as to occupy a predetermined area on the XY plane in the drawing.

Each heat generating portion 22 is made of a material having a low electric resistance. Each heat generating portion 22 can be made of a metal material. Each heat generating portion 22 is selected from materials having a lower thermal conductivity than copper. For example, each heat generating portion 22 can be configured by using a metal such as copper, an alloy of copper and tin (Cu—Sn), silver, tin, stainless steel, nickel, and nichrome, and an alloy containing these.

By being heated to a predetermined radiation temperature, the heat generating unit 22 can radiate radiant heat H that makes the occupant 12, that is, a person feel warm. Each heat generating portion 22 is made of a material having a high thermal conductivity.

Each energizing portion 26 has a rectangular shape extending in the direction of the axis X, and is arranged at both ends of the plurality of heat generating portions 22 in the axis Y direction. Each energizing portion 26 is made of a material having a low electrical resistance. One of the energizing units 26 is connected to the plurality of heat generating units 22 and connected to the power supply terminal 221 at one end side of the plurality of heat generating units 22 in the axial Y direction. Further, the other end of the energizing unit 26 is connected to the plurality of heat generating units 22 and connected to the ground terminal 222 on the other end side of the plurality of heat generating units 22 in the axial Y direction.

On the back surface side (that is, the anti-human body side) of the heat generating portion 22, the heat generating portion side low thermal conductive portion 21 having a lower thermal conductivity than the heat generating portion 22 is arranged. The heat-generating portion-side low heat-conducting portion 21 is arranged so as to cover the heat-generating portion 22 from the back surface side of the heat-generating portion 22. The low heat conductive portion 21 on the heat generating portion side has high insulating properties, and is made of, for example, a polyimide film, an insulating resin, or the like.

The heat generating layer 220 has a large thermal resistance in the surface direction of the heat generating layer 220 because the heat generating portion side low thermal conductive portion 21 having a lower thermal conductivity than each heat generating portion 22 is arranged between the plurality of heat generating portions 22. Has been done.

As described above, the heat generating layer 220 of the present embodiment has a low heat capacity and a high heat resistance, and when it comes into contact with an object, the heat transfer in the surface direction of the heat generating layer 220 is suppressed, and the contacted portion thereof. The temperature drops quickly. The thickness of the plurality of heat generating portions 22 is preferably 50 microns or less, and further preferably 20 microns or less in order to sufficiently reduce the heat transfer in the plane direction of the heat generating layer 220.

The volume of each heat generating portion 22 is set so as to reduce the heat capacity. The heat capacity of each heat generating portion 22 is set so that when an object comes into contact with the surface of the heater device, the surface temperature of the radiant heater device at the contact portion falls below a predetermined temperature in a short time. In a desirable form, the heat capacity of each heat generating portion 22 is set so that the surface temperature of the contact portion is lower than 60 ° C. when a finger or the like of a human body comes into contact with the surface of the heater device.

The insulating substrate 23 is made of a resin material that provides excellent electrical insulation and withstands high temperatures. Specifically, the insulating substrate 23 is made of a resin film. A plurality of paired electrodes 24 are arranged on the surface side (that is, the human body side) of the insulating substrate 23. The insulating substrate 23 has a lower thermal conductivity than the heat generating portion 22.

The electrode 24 has a transmitting electrode 24a and a receiving electrode 24b arranged apart from each other. The transmitting electrode 24a and the receiving electrode 24b are formed adjacent to the surface side of the insulating substrate 23. That is, a plurality of transmitting electrodes 24a and a plurality of receiving electrodes 24b are formed on the surface side of the insulating substrate 23.

Each transmitting electrode 24a has a rectangular shape extending in the direction of the axis Y, and each receiving electrode 24b has a rectangular shape extending in the direction of the axis Y. The transmitting electrode 24a and the receiving electrode 24b constituting the pair of electrodes 24 are arranged adjacent to each other so as to be aligned in the direction of the axis X. Such electrodes 24 are arranged at predetermined intervals in the direction of the axis Y. The transmitting electrode 24a and the receiving electrode 24b are made of a conductive metal such as copper. The transmitting electrode 24a and the receiving electrode 24b are made of the same material.

The plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b are regularly arranged so as to occupy a predetermined area on the XY plane in the drawing. The plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b each have a predetermined area on the XY plane in the drawing for generating the capacitance required for capacitance detection.

The plurality of transmitting electrodes 24a are connected to the same positive electrode terminal 241 via the conductive portion 243, and the plurality of receiving electrodes 24b are connected to the same negative electrode terminal 242 via the conductive portion.

When a predetermined voltage is applied between the positive electrode terminal 241 and the negative electrode terminal 242, an electric field is formed between the paired transmitting electrode 24a and the receiving electrode 24b. Then, when an object such as a finger approaches in this electric field, the proximity or contact of the object such as a finger to each electrode 24 is detected by detecting the change in the capacitance.

The plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b are dispersedly arranged on the surface side of the insulating substrate 23. Each of the plurality of transmitting electrodes 24a is separated from any of the plurality of receiving electrodes 24b. Each of the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b is made of a material having high thermal conductivity. The plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b each have a higher thermal conductivity than the insulating substrate 23.

On the surface side (that is, the human body side) of each transmitting electrode 24a and each receiving electrode 24b, an electrode-side low thermal conductivity portion 25 having a thermal conductivity lower than that of each transmitting electrode 24a and each receiving electrode 24b is arranged. The electrode-side low heat conductive portion 25 is arranged so as to cover each transmitting electrode 24a and each receiving electrode 24b from the surface side of each transmitting electrode 24a and each receiving electrode 24b. The electrode-side low heat conductive portion 25 has high insulating properties, and is made of, for example, a polyimide film, an insulating resin, or the like.

Further, between each transmitting electrode 24a and each receiving electrode 24b, an electrode-side low thermal conductive portion 25 having a thermal conductivity lower than that of each transmitting electrode 24a and each receiving electrode 24b is arranged. As a result, the thermal resistance of the heat generating layer 220 in the plane direction is increased. Further, each transmitting electrode 24a and each receiving electrode 24b are in the form of a thin film, and are dispersedly arranged on the surface side of the insulating substrate 23. Therefore, each transmitting electrode 24a and each receiving electrode 24b of the present embodiment have a low heat capacity.

As described above, each transmitting electrode 24a and each receiving electrode 24b have a low heat capacity and a high thermal resistance, and when they come into contact with an object, heat transfer in the surface direction of the heat generating layer is suppressed, and the contacted portion. It has the property that the temperature of the surface drops rapidly.

The thickness of the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b is preferably 50 microns or less, and further, the heat transfer in the plane direction of the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b is sufficiently small. In order to do so, it is preferably 20 microns or less.

Next, the block configuration of the heater device 20 of the present embodiment will be described with reference to FIG. The heater device 20 includes a detection unit 30, a supply unit 50, and a control unit 40.

The detection unit 30 forms an electric field between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b, and detects objects around the transmitting electrodes 24a and the receiving electrodes 24b. Specifically, the detection unit 30 applies a predetermined voltage between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b, and between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b. Form an electric field. Along with this, the detection unit 30 detects the capacitance between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b. Then, the detection unit 30 sends a signal indicating the detected capacitance to the control unit 40.

The supply unit 50 supplies electric power to the heat generation unit 22 in response to an instruction from the control unit 40. The supply unit 50 controls the amount of electricity supplied to the plurality of heat generating units 22. Energization of the heat generating unit 22 is performed via the supply unit 50.

The control unit 40 is configured as a computer equipped with a CPU, a memory, and the like. When the CPU executes the program stored in the memory, various processes described later in the control unit 40 are realized. As a result, the control unit 40 controls the energization from the supply unit 50 to the heat generation unit 22. Memory is a non-transitional substantive storage medium.

Next, the processing of the control unit 40 will be described with reference to FIGS. 5, 6, and 7. The process shown in FIG. 5 is a process executed by the control unit 40 based on the fact that the power is turned on to the heater device 20.

When the power is turned on to the heater device 20, the heater device 20 is activated. When the heater device 20 is activated, the detection unit 30 repeatedly applies a pulsed pulse voltage to the transmitting electrode 24a to form an electric field between the transmitting electrode 24a and the receiving electrode 24b. As a result, as shown in FIG. 6, an electric field E is formed between the transmitting electrode 24a and the receiving electrode 24b.

Then, the detection unit 30 uses a well-known method between the transmitting electrode 24a and the receiving electrode 24b based on the voltage between the transmitting electrode 24a and the receiving electrode 24b when a predetermined period has elapsed from the fall of the pulse voltage. Start detecting capacitance. Then, the detection unit 30 starts repeatedly outputting a signal indicating the detected capacitance to the control unit 40. Hereinafter, the capacitance between the transmitting electrode 24a and the receiving electrode 24b is simply referred to as a capacitance.

In the process of FIG. 5, the control unit 40 first specifies the value of the capacitance based on the signal indicating the capacitance output from the detection unit 30 in step S105, and the specified value is the capacitance C1. Record in memory as. This capacitance C1 corresponds to the reference capacitance. Further, the capacitance C1 is determined only after the capacitance between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b detected by the detection unit 30 starts to be applied to the electrodes 24 to the control unit 40. The capacitance to be recorded.

Subsequently, in step S110, it is determined whether or not the capacitance C1 recorded in step S105 is within the predetermined range Cm. The predetermined range Cm used here is a range having a fixed upper limit value and lower limit value previously recorded in the memory.

This predetermined range is a range in which the capacitance detected by the detection unit 30 should be contained if the heater device 20 is in a normal use state at the time of starting. If the capacitance C1 is within the predetermined range Cm, the process proceeds to step S115.

In step S115, the control unit 40 controls the supply unit 50 to start energization of the plurality of heat generating units 22. By this energization, the plurality of heat generating portions 22 start to generate heat. The temperature of each heat generating portion 22 that has generated heat rises to, for example, about 100 ° C., and begins to radiate radiant heat H that makes the occupant 12 feel warm.

Subsequently, in step S120, the control unit 40 identifies the value of the capacitance based on the signal indicating the latest capacitance output from the detection unit 30, and sets the specified value as the current capacitance C. Record in memory.

Subsequently, in step S125, the control unit 40 determines whether or not the absolute value of the value obtained by subtracting the capacitance C1 recorded in step S105 from the capacitance C recorded in step S120 is larger than the reference value Ct. do.

When an object such as a finger is not sufficiently close to or in contact with the electrode 24, the current capacitance C is substantially the same as the capacitance C1. In that case, the absolute value of the value obtained by subtracting the capacitance C1 recorded in step S105 from the capacitance C recorded in step S120 becomes smaller than the reference value Ct.

In this case, the control unit 40 returns from step S125 to step S120. That is, while an object such as a finger is not sufficiently close to or in contact with the electrode 24, the control unit 40 repeats the processes of steps S120 and S125 while continuing to energize the plurality of heat generating units 22.

On the other hand, as shown in FIG. 7, when an object such as a finger approaches at least one of the transmitting electrode 24a and the receiving electrode 24b, a part of the electric field formed between the transmitting electrode 24a and the receiving electrode 24b is on the fingertip side. The electric field detected by the receiving electrode 24b is reduced. As a result, the capacitance between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b is reduced. Then, as shown in FIG. 7, when an object such as a finger sufficiently approaches or comes into contact with at least one of the transmitting electrode 24a and the receiving electrode 24b, the capacitance C recorded in step S120 to the capacitance C1 recorded in step S105. The absolute value of the value obtained by subtracting is larger than the reference value Ct.

In this case, the control unit 40 proceeds from step S125 to step S130, controls the supply unit 50, and ends the energization of the plurality of heat generating units 22. By this energization stop, the plurality of heat generating portions 22 stop the radiation of the radiant heat H that makes the occupant 12 feel warm. This reduces the possibility that an object that approaches or comes into contact with the heat generating unit 22 will be excessively heated by the heat generating unit 22. After step S130, the process of FIG. 5 ends. As described above, the determination performed in step S125 is a determination as to whether or not to stop the energization of the heat generating portion 22.

Even when the heater temperature of the heater device 20 is raised to a temperature that can provide a feeling of heating to the occupant (for example, about 100 ° C.), when the occupant comes into contact with the heater surface, the temperature of the contacted portion rapidly decreases. .. Specifically, the temperature of the contacted portion drops to 52 ° C. or lower at which the reflection reaction of the occupant due to heat does not occur.

Further, when the heater device 20 detects the proximity or contact of a surrounding object, the heater device 20 stops energizing the heat generating portion 22. Therefore, for example, even if the contact with the heater surface continues for a relatively long time without noticing that the occupant has touched the surface of the heater device, it is unlikely to cause thermal discomfort to the occupant.

Here, a case where an object such as a finger is sufficiently close to or in contact with the electrode 24 will be described from before the heater device 20 is started to immediately after the start. In such a case, the capacitance C1 detected by the detection unit 30 immediately after the heater device 20 is started and recorded by the control unit 40 in step S105 does not fall within the predetermined range Cm which should be within the normal use state. ..

In such a case, as a comparative example different from the present embodiment, if the process immediately proceeds from step S105 to step S115, the detection of an object such as a finger may become inaccurate. Specifically, even if an object such as a finger sufficiently approaches or contacts the electrode 24, the energization of the plurality of heat generating portions 22 is not stopped, or an object such as a finger does not sufficiently approach the electrode 24. Nevertheless, there is a possibility that the energization of the plurality of heat generating portions 22 may be stopped.

Hereinafter, the reason why this happens in the comparative example will be described with reference to FIG. The vertical axis of the graph of FIG. 8 is the capacitance between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b, and the horizontal axis is time. That is, the graph of FIG. 8 shows the change with time of the capacitance detected by the detection unit 30.

In the comparative example, if an object such as a finger is not sufficiently close to the electrode 24 and is not in contact with the electrode 24 from before the heater device 20 is started to at the time point t1 immediately after the start, the change with time of the capacitance is shown by the broken line 301. It changes like. That is, at the time point t1, the capacitance C1 (hereinafter referred to as the capacitance C1a) recorded in step S105 falls within the predetermined range Cm. Then, at the time point t2 after the time point t1, when an object such as a finger sufficiently approaches or comes into contact with the electrode 24, the absolute value of the difference between the capacitance Ca and the capacitance C1a recorded in step S120 | Ca. -C1a | = ΔCa is larger than the reference value Ct. As a result, the control unit 40 proceeds from step S125 to step S130 to stop energization of the plurality of heat generating units 22. This is unlikely to cause thermal discomfort to the occupants.

However, in the comparative example, if an object such as a finger is sufficiently close to or in contact with the electrode 24 from before the heater device 20 is started to at the time point t1 immediately after the start, the change with time of the capacitance is as shown by the solid line 302. Changes to. That is, at the time point t1, the capacitance C1 (hereinafter referred to as the capacitance C1b) recorded in step S105 does not fall within the predetermined range Cm and becomes lower than the lower limit value of the predetermined range Cm. In the comparative example, the control unit 40 proceeds from step S105 to step S115 without going through step S110. Then, at the time point t2 after the time point t1, when an object such as a finger sufficiently approaches or comes into contact with the electrode 24, the absolute value of the difference between the capacitance Cb and the capacitance C1 recorded in step S120 | Cb—C1b | = ΔCb is smaller than the reference value Ct. This is because the capacitance Cb is below the normal predetermined range Cm, and even if an object such as a finger sufficiently approaches or comes into contact with the electrode 24, the amount of reduction in the capacitance is not sufficient. be. As a result, the control unit 40 returns from step S125 to step S120 to continue energization. That is, it cannot be detected that an object such as a finger is sufficiently close to or touches the electrode 24. Therefore, it is likely to cause thermal discomfort to the occupants.

Alternatively, in the comparative example, at the time point t1 immediately after the heater device 20 is started, the capacitance C1 recorded in step S105 does not fall within the predetermined range Cm due to some external abnormality, and is above the upper limit value of the predetermined range Cm. Can also be high. Here, the external factor means a factor other than the heater device 20. In this case, in the comparative example, the control unit 40 proceeds from step S105 to step S115 without going through step S110. Then, at a certain time point after the time point t1, the difference between the capacitance C and the capacitance C1 recorded in step S120 even though the object such as a finger is not in contact with or sufficiently close to the electrode 24. The absolute value of may be larger than the reference value Ct. As a result, the control unit 40 proceeds from step S125 to step S130, and stops energizing the plurality of heat generating units 22. As a result, the energization of the plurality of heat generating portions 22 is stopped at unnecessary timings. As described above, when the capacitance C1 recorded in step S105 is higher than the upper limit of the predetermined range Cm, there is a possibility that an object such as a finger may be erroneously detected as being sufficiently close to or in contact with the electrode 24. There is.

On the other hand, in the present embodiment, the control unit 40 executes step S110 after step S105. Therefore, as described above, when the capacitance C1b recorded in step S105 at the time point t1 is lower than the lower limit of the predetermined range Cm, the control unit 40 has the capacitance C1b within the predetermined range Cm in step S110. Judge that it is not included. Then, the control unit 40 ends the process of FIG. 5 while bypassing step S115, that is, prohibiting the process of steps S115-S130. As a result, it is possible to prevent the occupant from being given thermal discomfort. The time point t1 corresponds to the reference time point.

Further, as described above, when the capacitance C1 recorded in step S105 at the time point t1 is higher than the upper limit value of the predetermined range Cm, the control unit 40 sets the capacitance C1b within the predetermined range Cm in step S110. Judge that it is not included. Then, the control unit 40 ends the process of FIG. 5 by bypassing step S115, that is, without energizing the plurality of heat generating units 22. This makes it possible to prevent an object such as a finger from being erroneously detected as being sufficiently close to or in contact with the electrode 24.

Further, for example, when one or both of a part of the transmitting electrode 24a and a part of the receiving electrode 24b are disconnected at the positions marked with x as illustrated in FIG. 9 due to disturbance before the heater device 20 is started. Will be explained. In such a case, the change with time of the capacitance detected by the detection unit 30 after the heater device 20 is started is the same as that of the solid line 302 in FIG. That is, the capacitance C1 detected by the detection unit 30 after the heater device 20 is activated and recorded by the control unit 40 in step S105 does not fall within the predetermined range Cm that should be entered under normal usage conditions, and does not fall within the predetermined range Cm. It will be lower than the lower limit of. In this case, the control unit 40 determines in step S110 that the capacitance C1 is not within the predetermined range Cm. Then, the control unit 40 ends the process of FIG. 5 by bypassing step S115, that is, without energizing the plurality of heat generating units 22. As a result, it is possible to prevent the occupant from being given thermal discomfort.

As described above, in the present embodiment, the control unit 40 determines whether or not the capacitance C1 between the plurality of transmitting electrodes 24a and the receiving electrode 24b at the time point t1 is within the predetermined range Cm. Then, when the control unit 40 determines that the capacitance C1 is within the predetermined range Cm, the control unit 40 executes step S115-step S130. On the other hand, when the control unit 40 determines that the capacitance C1 is not within the predetermined range Cm, the control unit 40 prohibits the execution of step S115-step S130.

As described above, when it is determined that the capacitance C1 at the time point t1 before the heating unit 22 is energized is not within the predetermined range Cm, the execution of steps S115-S130 is prohibited. Therefore, there is a possibility that the determination in step S125 will be inaccurate in a situation where the object is already sufficiently close to or in contact with the heat generating portion before the heat generating portion 22 is energized, or the electrodes are disconnected. Is reduced.

More specifically, when the control unit 40 determines that the capacitance C1 is not within the predetermined range Cm, the control unit 40 prohibits the start of energization of the heat generation unit 22. By doing so, the problem in the situation where the object is already sufficiently close to or in contact with the heat generating portion 22 at the time point t1 or the electrode 24 is broken is solved. Further, the problem in the situation where the object is already sufficiently close to or in contact with the heat generating portion 22 before the heat generating portion 22 is energized, or the electrode 24 is disconnected is solved. That is, the possibility that the object comes into contact with the heat generating portion and is excessively heated due to the inaccuracies in the object determination (that is, the determination in step S125) is reduced.

(Second Embodiment)
Next, the second embodiment will be described. The heater device 20 of the present embodiment is different from the heater device 20 of the first embodiment in that it further has a temperature sensor (not shown). Further, the control unit 40 of the present embodiment executes the process shown in FIG. 10 instead of the process shown in FIG. The process of FIG. 10 is different from the process of FIG. 5 in that step S123 is executed after step S120 is executed and step S125 is executed. Steps having the same processing content in FIGS. 5 and 10 are assigned the same step number. Further, the control unit 40 of the present embodiment executes the process shown in FIG. 11 in parallel with the process shown in FIG. 10 in addition to the process shown in FIG. Other configurations of the heater device 20 of the present embodiment are the same as those of the first embodiment.

The temperature sensor is arranged in the vicinity of the heat generating unit 22, detects the temperature of the heat generating unit 22, and outputs a detection signal corresponding to the detected temperature to the control unit 40. This temperature sensor may be arranged in contact with the heat generating portion 22 in the heat generating layer 220, or may be embedded in the insulating substrate 23.

In the process of FIG. 10, the control unit 40 specifies the capacitance C in step S120, applies the correction value P to the capacitance C in step S123, and then corrects in step S125. The above determination is made using the capacitance C after the value P has been applied. The application of the correction value P will be described later. The correction value P is set to 0, which is the default value, when the heater device 20 is started.

The process shown in FIG. 11 is executed by the control unit 40 based on the fact that the power is turned on to the heater device 20. In the process of FIG. 11, the control unit 40 first determines in step S205 whether or not the energization to the heat generating unit 22 has been turned on from off, and if not, returns to step S205. When the energization to the heat generating unit 22 is changed from off to on, the control unit 40 proceeds from step S205 to step S210. The on / off of energization of the heat generating unit 22 is controlled in the process of FIG.

After the energization to the heating unit 22 is first turned on after the heater device 20 is started, the temperature of the heating unit 22 rises with the passage of time and gradually stabilizes. The amount of energization to the heat generating unit 22 is adjusted in advance at the time of manufacturing the heater device 20 so that the temperature of the heat generating unit 22 stabilizes at a predetermined target temperature. The stabilization of the temperature of the heat generating unit 22 means that the absolute value of the amount of change in the temperature of the heat generating unit 22 per unit time is sufficiently reduced.

FIG. 12 shows the change with time of the temperature of the heat generating portion 22 by the solid line 311. As shown in the solid line 311, the temperature of the heat generating unit 22 rises after the time t1 when the energization to the heat generating unit 22 is turned on from off, and the temperature rise rate decreases with the passage of time. Then, in the vicinity of the target temperature Tx, the temperature rise rate becomes close to zero.

Further, FIG. 12 shows the change with time of the capacitance between the transmitting electrode 24a and the receiving electrode 24b by a solid line 312. As shown in this figure, it is sufficient that an object other than the heater device 20 is in contact with the electrode 24 as the temperature of the heating unit 22 rises after t1 when the energization of the heating unit 22 is turned from off to on. Capacitance may decrease even though they are not close to each other. This is due to the deformation of the heater device 20 due to heat.

Specifically, as the temperature of the heat generating portion 22 rises, the insulating substrate 23, the low heat conducting portion 25 on the electrode side, the low heat conducting portion 21 on the heat generating portion side, and the like expand, and as a result, the state as shown in FIG. 13 is changed to FIG. The state may change to the state shown in. That is, the distance between the transmitting electrode 24a and the receiving electrode 24b may become long. As the distance between the transmitting electrode 24a and the receiving electrode 24b becomes longer, the capacitance decreases. Alternatively, the heater device 20 bends due to the difference in the linear expansion rate between the heat generating portion side low heat conducting portion 21, the heat generating portion 22, and the electrode side low heat conducting portion 25, and as a result, between the transmitting electrode 24a and the receiving electrode 24b. Capacitance is reduced.

In step S210 following step S205, the control unit 40 identifies the temperature of the heat generating unit 22 based on the detection signal input from the temperature sensor. Further, the control unit 40 determines in step S215 whether or not the temperature of the heat generating unit 22 has stabilized. Whether or not the temperature of the heat generating portion 22 is stabilized is determined by whether or not the temperature specified in the immediately preceding step S210 is within a predetermined temperature range Tm centered on the target temperature Tx. For example, the lower limit of the temperature range Tm may be 0.95 times the target temperature Tx. Further, for example, the upper limit of the temperature range Tm may be 1.05 times the target temperature Tx.

If the temperature specified in the immediately preceding step S210 is within the temperature range Tm, the process proceeds to step S220. If the temperature specified in the immediately preceding step S210 is not within the temperature range Tm, it is determined that the temperature of the heat generating unit 22 is not stabilized, and the process returns to step S210.

In the example of FIG. 12, during the period between the time point t1 and the time point t6, the control unit 40 repeatedly executes steps S210 and S215 by determining in step S215 that the temperature of the heat generating unit 22 is not stabilized.

At the time point t6, the temperature of the heat generating portion 22 falls within the temperature range Tm. Then, in step S215 immediately after that, the temperature specified in step S210 immediately before is within the temperature range Tm. Therefore, the control unit 40 determines that the temperature of the heat generating unit 22 has stabilized at that time, and proceeds to step S220. The time point t6 corresponds to the correction time point.

In step S220, the control unit 40 specifies the value of the capacitance based on the signal indicating the latest capacitance output from the detection unit 30, and sets the value as the capacitance Cx. Subsequently, in step S225, the correction value P is changed. Specifically, the correction value P is changed from the default value to a value corresponding to the value of the capacitance Cx specified immediately before. Specifically, the value obtained by subtracting the capacitance Cx from the capacitance C1 is defined as the correction value P. After step S225, the process of FIG. 11 ends.

If the capacitance Cx is corrected using the correction value P calculated in this way, that is, if the correction value P is added to the capacitance Cx, the corrected capacitance Cx + P becomes the capacitance. It will be the same as C1. Therefore, the absolute value of the difference between the corrected capacitance Cx + P and the capacitance C1 becomes zero. That is, the correction value P is a correction value for reducing the absolute value of the difference between the corrected capacitance Cx + P and the capacitance C1 to zero.

In step S123 of FIG. 10, the control unit 40 applies the correction value P to the capacitance C specified in the immediately preceding step S120, as described above. Specifically, the result of adding the correction value P to the capacitance C is referred to as a new capacitance C. Since the correction value P is zero from the time point t1 to t6 when the temperature of the heat generating portion 22 is not stable, the capacitance C specified in the immediately preceding step S120 and the new capacitance value C are the same value. Therefore, the capacitance value C used in step S125 following step S123 is the capacitance value C that has not been corrected in step S123.

After t6 when the temperature of the heat generating portion 22 stabilizes, the correction value P becomes a positive value different from zero. Therefore, the capacitance C specified in the immediately preceding step S120 is changed to a new capacitance C. That is, the capacitance C used in step S125 is the capacitance value C corrected in the immediately preceding step S123.

Specifically, as shown by the solid line 312 in FIG. 12, the capacitance C is corrected so that the corrected capacitance C at the time point t6 is the same as the capacitance C1. After the time point t6, a value larger than the capacitance C specified in the immediately preceding step S120 becomes the corrected capacitance C.

The significance of doing so will be explained. When the capacitance C detected by the detection unit 30 is smaller than the capacitance C1 even though an object such as a finger is neither in contact with the electrode 24 nor sufficiently close to the electrode 24, the detection unit 30 after the time point t6 The absolute value of the difference between the detected capacitance C and the capacitance C1 becomes large. Moreover, this absolute value tends to increase as an object such as a finger approaches the electrode 24. That is, after the time point t6, since | C—C1 | becomes larger than the reference value Ct, the amount that the capacitance C must decrease decreases. Therefore, if the capacitance C is not corrected in step S123, even if an object such as a finger is not sufficiently close to the electrode 24, | C-C1 | becomes larger than the reference value Ct in step S125. There is a possibility that it will end up. That is, there is a possibility that an object such as a finger may be erroneously detected as being sufficiently close to or in contact with the electrode 24.

On the other hand, in the present embodiment, the control unit 40 corrects and increases the capacitance C in step S123 to bring the capacitance C closer to the capacitance C1 than it actually is. By doing so, the absolute value of the difference between the corrected capacitance C and the capacitance C1 becomes small. Therefore, when an object such as a finger is not sufficient but approaches the electrode 24 a little, the possibility that | C—C1 | becomes larger than the reference value Ct in step S125 is reduced. That is, the possibility of false positives is reduced.

In fact, as shown in FIG. 12, when an object such as a finger approaches the electrode 24 at a time point t7 after the time point t6, the corrected capacitance C decreases and the object separates from the electrode 24. At the time point t8, the corrected capacitance C increases. Since the corrected capacitance C immediately before the time point t7 is almost the same as the capacitance C1, the control unit 40 stops energization in step S125 according to the distance between the object such as a finger and the electrode 24. The continuation can be properly decided.

Further, as the temperature of the heat generating unit 22 rises, the capacitance C detected by the detection unit 30 is larger than the capacitance C1 even though an object such as a finger is not in contact with or sufficiently close to the electrode 24. May also be large. In that case, after the time point t6 when the temperature of the heat generating portion 22 stabilizes, the amount in which the capacitance C must decrease increases because | C—C1 | becomes larger than the reference value Ct. Therefore, if the capacitance C is not corrected downward in step S123, | C-C1 | may not be larger than the reference value Ct in step S125 even if an object such as a finger sufficiently approaches or comes into contact with the electrode 24. There is sex. That is, it may not be possible to detect that an object such as a finger is sufficiently close to or touches the electrode 24.

On the other hand, in the present embodiment, the control unit 40 corrects and reduces the capacitance C in step S123. This is because the correction value P is a negative value in this case. As a result, the capacitance C is closer to the capacitance C1 than it actually is. By doing so, the amount of the corrected capacitance C that must be reduced is reduced because | C—C1 | becomes larger than the reference value Ct in step S125. That is, the possibility that it becomes impossible to detect that an object such as a finger is sufficiently close to or touches the electrode 24 is reduced.

Further, the control unit 40 sets the correction value P when the temperature of the heat generating unit 22 is stabilized. Therefore, the correction value P becomes an appropriate value.

In the present embodiment, the control unit 40 stops and does not stop energization in step S125 of FIG. 10 during the period from the time point t1 to the time point t6, that is, even before the temperature of the heat generating unit 22 stabilizes. Is determined. However, in the period from the time point t1 to the time point t6, the control unit 40 does not have to determine whether the energization is stopped or not in step S125 of FIG. 10 before the temperature of the heat generating unit 22 stabilizes. In that case, the control unit 40 does not stop energizing the heat generating unit 22 based on the capacitance C during the period from the time point t1 to the time point t6.

As described above, the control unit 40 has a capacitance (Cx) and a capacitance between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b at the time point t6 after the energization of the heating unit 22 is started. The correction value P for reducing the absolute value of the difference from C1 is calculated.

Then, the control unit 40 generates heat based on the capacitance C between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b, the capacitance C1, and the correction value P at the time point t7 after the time point t6. It is determined whether or not to reduce the amount of electricity supplied to 22.

In this way, the correction value P is used to determine whether or not to reduce the amount of energization to the heat generating portion 22 at the time point t7 after the time point t6. By doing so, the correction value P corresponding to the deformation of the heater device 20 due to the temperature rise can be applied to the object determination at a later time point. As a result, it is possible to reduce the influence of the deformation of the heater device 20 after energizing the heat generating portion 22 on the object determination. Therefore, it is possible to reduce the possibility that the object determination becomes inaccurate due to the deformation of the heater device 20 after the energization of the heat generating portion 22.

Further, the control unit 40 determines whether or not the temperature of the heat generating unit 22 has stabilized after the energization of the heat generating unit 22 is started. The time point t6 is a time point after it is determined that the temperature of the heat generating portion 22 has stabilized. As described above, since the time point t6 is the time point after the temperature of the heat generating portion 22 is stabilized, the accuracy of the correction is improved.

Further, the control unit 40 determines whether or not the temperature of the heat generating unit 22 is stabilized based on the temperature of the heat generating unit 22 detected by the temperature sensor. In this way, by determining whether or not the temperature of the heat generating portion 22 is stabilized based on the detection result of the temperature sensor, it is possible to determine the stabilization more directly. It should be noted that the same effect as that of the first embodiment is realized in this embodiment as well.

(Third Embodiment)
Next, the third embodiment will be described. In this embodiment, as a method for detecting that the temperature of the heat generating unit 22 has stabilized, a method using the elapsed time from the energization on time of the heat generating unit 22 is adopted. In the heater device 20 of the present embodiment, the processing content of the control unit 40 is changed from that of the heater device 20 of the second embodiment. Specifically, the control unit 40 executes the process shown in FIG. 15 instead of the process shown in FIG. The steps having the same processing contents in FIGS. 15 and 11 are assigned the same step numbers. In the process of FIG. 15, steps S210 and S215 are abolished and step S213 is added to the process of FIG. The other heater device 20 has the same configuration as that of the second embodiment.

If the control unit 40 determines in step S205 that the energization to the heat generating unit 22 is turned on in the process of FIG. 15, the control unit 40 proceeds to step S213. In step S213, it is determined whether or not the reference time Tr has elapsed since the energization of the heat generating portion 22 was started. The reference time Tr is set in advance at the time of manufacturing the heater device 20 as the time from the start of energization of the heat generating unit 22 to the stabilization of the temperature of the heat generating unit 22.

If it is determined in step S213 that the reference time Tr has not elapsed since the start of energization, the control unit 40 executes step S213 again. When it is determined in step S213 that the reference time Tr has elapsed from the start of energization, the control unit 40 changes the correction value P from the default value by executing steps S220 and S225, as in the second embodiment.

In this way, it is also possible to detect that the temperature of the heat generating unit 22 has stabilized by using the elapsed time from turning on the power to the heat generating unit 22. This makes it possible to make a simpler determination of stabilization. It should be noted that the same effect as that of the second embodiment is realized in this embodiment as well.

(Fourth Embodiment)
Next, the fourth embodiment will be described. In this embodiment, as a method for detecting that the temperature of the heat generating unit 22 has stabilized, a method using the capacitance C detected by the detecting unit 30 is adopted. In the heater device 20 of the present embodiment, the processing content of the control unit 40 is changed from that of the heater device 20 of the second embodiment. Specifically, the control unit 40 executes the process shown in FIG. 16 instead of the process shown in FIG. The steps having the same processing contents in FIGS. 16 and 11 are assigned the same step numbers. In the process of FIG. 16, steps S210 and S215 are abolished, and steps S211 and S212 are added to the process of FIG. The other heater device 20 has the same configuration as that of the second embodiment.

If the control unit 40 determines in step S205 that the energization to the heat generating unit 22 is turned on in the process of FIG. 15, the control unit 40 proceeds to step S211. In step S211 the value of the capacitance is specified based on the signal indicating the latest capacitance output from the detection unit 30, and the specified value is set as the current capacitance C.

Subsequently, the control unit 40 determines in step S212 whether or not the capacitance C is stabilized. Then, if it is determined that the capacitance C is not stabilized, the process returns to step S123, and if it is determined that the capacitance C is stabilized, the process proceeds to step S220.

As described in the second embodiment, the capacitance C detected by the detection unit 30 changes with the temperature change of the heat generation unit 22. Therefore, the capacitance C1 decreases as the temperature of the heat generating portion 22 rises after the time point t1 in FIG. 12, and after the time point t6, the temperature of the heat generating portion 22 is stabilized and stabilized. Therefore, detecting that the capacitance C is stable is equivalent to detecting that the temperature of the heat generating portion 22 is stabilized.

Here, the details of the determination as to whether or not the capacitance C has been stabilized in step S212 will be described. In step S212, the control unit 40 changes the capacitance C per unit time based on the capacitance C specified in the immediately preceding step S211 and the capacitance C specified in the previous step S212. Specify the absolute value of the quantity. Then, if the specified absolute value is less than the reference change amount, it is determined that the capacitance C is stabilized, and if it is not less than, it is determined that the capacitance C is not stabilized.

However, at the first execution opportunity of step S212 after the heater device 20 is started, the control unit 40 determines the capacitance C based on the capacitance C specified in the immediately preceding step S211 and the capacitance C1. Specify the absolute value of the amount of change per unit time. In this way, it is possible to determine whether or not to change the correction value P based on whether or not the capacitance C is stabilized.

As described above, whether or not the temperature of the heat generating portion 22 is stabilized is determined based on the capacitance between the plurality of transmitting electrodes 24a and the plurality of receiving electrodes 24b, in order to determine the stabilization. There is no need to provide an additional sensor such as a temperature sensor. It should be noted that the same effect as that of the second embodiment is realized in this embodiment as well.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be appropriately modified. Further, the above embodiments are not unrelated to each other, and can be appropriately combined unless the combination is clearly impossible. Further, in each of the above embodiments, the elements constituting the embodiment are not necessarily essential except when it is clearly stated that they are essential or when they are clearly considered to be essential in principle. Further, in each of the above embodiments, when numerical values such as the number, numerical values, quantities, and ranges of the constituent elements of the embodiment are mentioned, when it is clearly stated that they are particularly essential, and when it is clearly limited to a specific number in principle. It is not limited to the specific number except when it is done. In particular, when a plurality of values are exemplified for a certain amount, it is also possible to adopt a value between the plurality of values unless otherwise specified or when it is clearly impossible in principle. .. Further, in each of the above embodiments, when the shape, positional relationship, etc. of the constituent elements are referred to, the shape, the shape, etc. It is not limited to the positional relationship. Further, the present invention also allows the following modifications and equal range modifications for each of the above embodiments. It should be noted that the following modifications can be independently selected to be applied or not applied to the above embodiment. That is, any combination of the following modifications can be applied to the above embodiment.

In the above embodiment, the control unit 40 corresponds to the range determination unit by executing step S110, corresponds to the normal operating unit by executing steps S115-S130, and is specified by executing step S105. Corresponds to the department. Further, the control unit 40 corresponds to the calculation unit by executing step S225, and corresponds to the stability determination unit by executing steps S215, S213, and S212.

(Modification 1)
In each of the above embodiments, the control unit 40 stops energizing the heat generating unit 22 in step S130. That is, the current supplied to the heat generating unit 22 is reduced to zero. However, this does not necessarily have to be the case. For example, in step S130, the current supplied to the heat generating unit 22 may be reduced to 1/2. That is, in step S130, if the current supplied to the heat generating unit 22 is reduced, the possibility that an object approaching or in contact with the heat generating unit 22 will be excessively heated by the heat generating unit 22 is reduced.

(Modification 2)
In the second, third, and fourth embodiments, the control unit 40 corrects the capacitance C detected by the detection unit 30 at a time point after the time point t6 by using the correction value P in step S123. ing. However, this does not necessarily have to be the case. For example, the control unit 40 may use the correction value P to correct the capacitance C1 detected at the time point t1 before the heating unit 22 is energized. In this case, the control unit 40 compares the capacitance C detected at a time point after the time point t6 with the corrected capacitance C1 to reduce the energization to the heat generating unit 22. Is determined. Further, in this case, the new correction value P calculated in step S225 is a value obtained by subtracting the capacitance C1 from the capacitance Cx. Even in this case, the correction value P is a correction value for reducing the absolute value of the difference between the corrected capacitance C1 and the capacitance C to zero.

(Modification 3)
In the second, third, and fourth embodiments, the correction value P is a correction value for reducing the absolute value of the difference between the corrected capacitance C1 and the capacitance C to zero. It does not necessarily have to be this way. The correction value P may be a correction value in which the absolute value of the difference between the corrected capacitance C1 and the capacitance C is reduced to a value other than zero.

(Modification example 4)
In step S225 of the second, third, and fourth embodiments, the correction value P may be a value obtained by dividing the capacitance C1 from the capacitance C1. Such a correction value P is also a correction value for reducing the absolute value of the difference between the corrected capacitance C1 and the capacitance C to zero. In this case, in step S123, the corrected capacitance C is obtained by multiplying the capacitance C detected in step S120 by this correction value P.

(Modification 5)
In the second, third, and fourth embodiments, the time point t6 corresponding to the correction time point is a time point after the temperature of the heat generating portion 22 is stabilized, but it does not necessarily have to be such a time point. For example, the time point t6 corresponding to the correction time point may be before the time point when the temperature of the heat generating portion stabilizes. Even in that case, the possibility that the corrected object determination becomes inaccurate can be reduced to some extent.

(Modification 6)
In each of the above embodiments, when the capacitance C1 is not within the predetermined range Cm in step S110, the control unit 40 prohibits the start of energization of the heat generation unit 22. However, this does not necessarily have to be the case. When the capacitance C1 is not within the predetermined range Cm, the control unit 40 suffices to bypass the series of processes from step S115 to step S130. For example, when the capacitance C1 is not within the predetermined range Cm, the control unit 40 may energize the heat generating unit 22 with a very weak current and may not perform object determination.

(Modification 7)
In each of the above embodiments, the object determination is performed by the mutual capacitance method. Therefore, the capacitance of the electrode 24 used for the object determination in each of the above embodiments is the capacitance between the plurality of transmitting electrodes 24a constituting the electrode 24 and the plurality of receiving electrodes 24b. However, this does not necessarily have to be the case. The object determination may be performed by the self-capacity method. In this case, the capacitance of the electrode used for determining the object is the capacitance between the electrode and the object.

(Modification 8)
In each of the above embodiments, the time point t1 corresponding to the reference time point at which the step S105 is executed was before the heating unit 22 was energized. However, the reference time point for detecting and storing the reference capacitance may be after energization of the heat generating portion 22.

(summary)
According to the first aspect shown in part or all of the above embodiments, the control unit determines whether or not the reference capacitance, which is the capacitance of the electrode at the reference time, is within a predetermined range. When the range determination unit determines that the reference capacitance is within the predetermined range and the range determination unit determines that the reference capacitance is within the predetermined range, heat is generated based on the capacitance and the reference capacitance of the electrode at a time point after the reference time. It has a normal operating unit for determining whether or not to reduce the amount of electricity supplied to the unit. Further, when the range determination unit determines that the reference capacitance is not within the predetermined range, the range determination unit prohibits the operation of the normal operation unit.

Further, according to the second aspect, the reference time point is a time point before the heat generating portion is energized, and the normal operating portion is in the range when the reference capacitance is within the predetermined range. When the determination unit determines, energization of the heat generating portion is started, and the current time after the energization of the heat generating portion is started is based on the capacitance (C) of the electrode and the reference capacitance. , It is determined whether or not to reduce the amount of electricity supplied to the heat generating portion. By doing so, it is possible to reduce the possibility that the object determination becomes inaccurate due to the deformation of the heater device after energizing the heat generating portion.

Further, according to the third aspect, when the range determination unit determines that the reference capacitance is not within the predetermined range, the range determination unit prohibits the start of energization of the heat generation unit. By doing so, the object determination becomes inaccurate in the situation where the object is already sufficiently close to or in contact with the heat generating portion at the time of detecting the reference capacitance, or the electrode is broken. The possibility that the object comes into contact with the heat generating portion and is excessively heated is reduced.

Further, according to the fourth aspect, the control unit has a specific unit for specifying the reference capacitance and a correction time point after the reference time point and after the energization to the heat generation unit is started. A calculation unit for calculating a correction value for reducing the absolute value of the difference between the capacitance of the electrode and the reference capacitance is provided. The normal operating unit determines whether or not to reduce the amount of electricity supplied to the heat generating portion based on the capacitance of the electrode, the reference capacitance, and the correction value at a time point after the correction time point. do.

In this way, the correction value for reducing the absolute value of the difference between the capacitance of the electrode and the reference capacitance at the time of correction after the energization of the heat generating portion is started is at a time after the time of correction. , Used to determine whether to reduce the amount of electricity supplied to the heat generating portion. By doing so, the correction value P corresponding to the deformation of the heater device due to the temperature rise can be applied to the object determination at a later time point. As a result, it is possible to reduce the influence of the deformation of the heater device on the object determination after energizing the heat generating portion. As a result, it is possible to reduce the possibility that the object determination becomes inaccurate due to the deformation of the heater device after energizing the heat generating portion.

Further, according to the fifth aspect, the control unit is for reducing the absolute value of the difference between the capacitance of the electrode and the reference capacitance at the time of correction after the energization of the heat generating portion is started. Based on the calculation unit that calculates the correction value and the capacitance, reference capacitance, and correction value of the electrode at a time point after the correction time point, it is determined whether or not to reduce the energization amount to the heat generating part. It is equipped with a normal operating part.

Further, according to the sixth aspect, it has a stability determination unit that determines whether or not the temperature of the heat generation unit has stabilized after the energization of the heat generation unit is started, and the correction time point is the above. This is the time point after the stability determination unit determines that the temperature of the heat generating unit has stabilized. As described above, since the correction time point (t6) is the time point after the temperature of the heat generating portion is stabilized, the correction accuracy is improved.

Further, according to the seventh aspect, the stability determination unit determines whether or not the temperature of the heat generation unit is stabilized based on the temperature of the heat generation unit detected by the temperature sensor. In this way, by determining whether or not the temperature of the heat generating portion is stabilized based on the detection result of the temperature sensor, it is possible to determine the stabilization more directly.

Further, according to the eighth aspect, the stability determination unit determines whether or not the temperature of the heat generation unit is stabilized based on the time elapsed from the start of energization of the heat generation unit. In this way, by determining whether or not the temperature of the heat generating portion has stabilized based on the time elapsed from the start of energization, it is possible to make a simpler determination of stabilization.

Further, according to the ninth aspect, the stability determination unit determines whether or not the temperature of the heat generation unit is stabilized based on the capacitance of the electrode. As described above, by determining whether or not the temperature of the heat generating portion is stabilized based on the capacitance, it is not necessary to provide an additional sensor for determining the stabilization.

20 Heater device 24 Electrode 22 Heat generation unit 40 Control unit

Claims (9)

It ’s a heater device.
The heat generating part (22) that generates heat when energized,
The electrode (24) to which the voltage is applied and
A control unit (40) for controlling energization to the heat generating unit is provided.
The control unit
A range determination unit (S110) for determining whether or not the reference capacitance (C1), which is the capacitance of the electrode at the reference time point (t1), is within the predetermined range (Cm).
When the range determination unit determines that the reference capacitance is within the predetermined range, it is based on the capacitance (C) of the electrode and the reference capacitance at a time point after the reference time. , A normal operating unit (S115-S130) for determining whether or not to reduce the amount of electricity supplied to the heat generating unit.
A heater device that prohibits the operation of the normal operating unit when the range determining unit determines that the reference capacitance is not within the predetermined range. The reference time point is a time point before the heat generating portion is energized.
When the range determination unit determines that the reference capacitance is within the predetermined range, the normal operating unit starts energizing the heat generating portion, and after the energizing of the heat generating portion is started. The heater device according to claim 1, wherein it is determined whether or not to reduce the amount of electricity supplied to the heat generating portion based on the capacitance (C) of the electrode and the reference capacitance at the time point. The heater device according to claim 1 or 2, wherein when the range determination unit determines that the reference capacitance is not within the predetermined range, the start of energization of the heat generating unit is prohibited. The control unit includes a specific unit (S105) for specifying the reference capacitance and a specific unit (S105).
The absolute value of the difference between the capacitance (Cx) of the electrode and the reference capacitance at the correction time point (t6) after the reference time point and after the energization of the heat generating portion is started is reduced. A calculation unit (S225) for calculating a correction value (P) for the purpose is provided.
The normal operating portion reduces the amount of energization to the heat generating portion based on the capacitance (C) of the electrode, the reference capacitance, and the correction value at a time point (t7) after the correction time point. The heater device according to any one of claims 1 to 3, wherein it is determined whether or not the heater device is used. The heat generating part (22) that generates heat when energized,
The electrode (24) to which the voltage is applied and
A control unit (40) for controlling energization to the heat generating unit is provided.
The control unit
A specific unit (S105) that specifies the reference capacitance (C1), which is the capacitance of the electrode at the reference time point (t1), and
The absolute value of the difference between the capacitance (Cx) of the electrode and the reference capacitance at the correction time point (t6) after the reference time point and after the energization of the heat generating portion is started is reduced. Calculation unit (S225) for calculating the correction value (P) for
Based on the capacitance (C) of the electrode, the reference capacitance, and the correction value at a time point (t7) after the correction time point, it is determined whether or not to reduce the energization amount to the heat generating portion. A heater device including a normal operating unit (S115-S130). It has a stability determination unit (S215, S213, S212) that determines whether or not the temperature of the heat generation unit has stabilized after the energization of the heat generation unit is started.
The heater device according to claim 4 or 5, wherein the correction time point (t6) is a time point after the stability determination unit determines that the temperature of the heat generating unit has stabilized. The heater device according to claim 6, wherein the stability determination unit determines whether or not the temperature of the heat generation unit is stabilized based on the temperature of the heat generation unit detected by the temperature sensor. The heater device according to claim 6, wherein the stability determination unit determines whether or not the temperature of the heat generation unit has stabilized based on the time elapsed from the start of energization of the heat generation unit. The heater device according to claim 6, wherein the stability determination unit determines whether or not the temperature of the heat generating unit is stabilized based on the capacitance of the electrode.

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