TWI866052B - Abnormality determination device, abnormality determination system and abnormality determination method - Google Patents

Abstract

The present invention provides an abnormality determination device capable of determining the possibility of abnormality of a lamp heater at low cost. The abnormality determination device includes: an acquisition unit that acquires the resistance value of the electric heater of the lamp heater calculated based on the voltage at both ends of the electric heater and the current flowing through the electric heater; and a determination unit that determines whether the lamp heater is abnormal based on the acquired resistance value, i.e., abnormality determination. The determination unit determines that the lamp heater is abnormal when the acquired resistance value exceeds a first critical value.

Description

Abnormality determination device, abnormality determination system and abnormality determination method

The present invention relates to an abnormality determination device, an abnormality determination system and an abnormality determination method for determining an abnormality of a heater.

Patent document 1 discloses an electric heater that determines abnormality of the heater based on the magnitude of the change in the rate of increase of resistance when power is supplied. [Prior art document] [Patent document]

[Patent Document 1] Japanese Patent Publication No. 8-124653

[The problem that the invention wants to solve]

However, in lamp heaters such as halogen heaters among electric heaters, the emission of infrared rays is attenuated due to the blackening of the inside of the glass tube or the adhesion of dirt on the outside of the glass tube (hereinafter referred to as the blackening phenomenon), which may cause abnormalities such as insufficient heating or uneven heating. Therefore, in general, abnormalities of lamp heaters are detected by visually observing the blackening phenomenon of the glass tube or monitoring the image using a camera.

However, if the blackening of the glass tube is monitored visually or using camera images, the monitoring cost, such as labor costs and equipment costs, becomes high, so it may not be possible to always monitor the abnormality of the lamp heater. In such a case, the frequency of monitoring the blackening of the glass tube is reduced, and the abnormality of the lamp heater may be missed.

The present disclosure provides an abnormality determination device, an abnormality determination system, and an abnormality determination method capable of determining the possibility of an abnormality of a lamp heater at a low cost. [Means for solving the problem]

The abnormality determination device of one form disclosed in the present invention comprises: an acquisition unit, which acquires the resistance value of the electric heater of the lamp heater calculated based on the voltage at both ends of the electric heater and the current flowing through the electric heater; and a determination unit, which performs abnormality determination based on the acquired resistance value, wherein the abnormality determination is a determination of whether the lamp heater is abnormal. The determination unit determines that the lamp heater is abnormal when the acquired resistance value exceeds a first critical value.

The abnormality determination system of one form disclosed herein comprises: The abnormality determination device of the form; The lamp heater; and A control device for controlling the lamp heater.

One form of abnormality determination method disclosed in the present invention is: Obtaining the resistance value of the electric heater of the lamp heater calculated based on the voltage at both ends of the electric heater and the current flowing through the electric heater, When the obtained resistance value exceeds a first critical value, determining that the lamp heater is abnormal. [Effect of the invention]

By using the abnormality determination device of the above type, it is possible to realize an abnormality determination device that can determine the possibility of abnormality of a lamp heater at a low cost.

By using the abnormality determination system of the above type, it is possible to realize an abnormality determination system capable of determining the possibility of abnormality of a lamp heater at low cost.

By using the abnormality determination method of the above type, the possibility of abnormality of the lamp heater can be determined at a low cost.

An example of the present disclosure is described below with reference to the accompanying drawings. The following description is merely an example in nature and is not intended to limit the present disclosure, its applicable objects, or its use. The drawings are schematic, and the ratios of the dimensions, etc. may not necessarily be consistent with the actual ones.

As an example, as shown in FIG. 1 , an abnormality determination device 10 of an embodiment of the present disclosure constitutes a part of an abnormality determination system 1. The abnormality determination system 1 includes: a lamp heater 20 such as a halogen heater, and a thermostat 22 for controlling the temperature value of the lamp heater 20. The thermostat 22 is an example of a control device for controlling the lamp heater 20. In this embodiment, the abnormality determination system 1 includes, in addition to the lamp heater 20 and the thermostat 22, a solid state relay (SSR) 23, a temperature sensor 25, a voltage sensor 26, and an induction sensor 27.

As shown in FIG1 , the lamp heater 20 has an electric heating element 21 such as a heating wire. In the present embodiment, as an example, a thermostat 22 is connected to the electric heating element 21 via a solid-state relay 23, and a power source 24 is connected to the solid-state relay 23. The thermostat 22 controls the electric heating element 21 via the solid-state relay 23 so that the temperature value of the lamp heater 20 becomes a predetermined value based on the temperature value detected by the temperature sensor 25. When the solid-state relay 23 is turned on, a current from the power source 24 is supplied to the electric heating element 21. The amount of heat generated by the electric heating element 21 changes according to the amount of operation. The voltage sensor 26 detects the voltage at both ends of the electric heating element 21. The current sensor 27 detects the current flowing through the electric heater 21 .

The abnormality determination device 10 includes an acquisition unit 100 and a determination unit 110, and determines the abnormality of the lamp heater 20. As an example, the abnormality determination device 10 includes a processor 11, a memory unit 12, and a communication unit 13. Each of the acquisition unit 100 and the determination unit 110 is implemented, for example, by the processor 11 executing a prescribed program stored in the memory unit 12. The processor 11 includes a central processing unit (CPU), a micro processing unit (MPU), a graphic processing unit (GPU), a digital signal processor (DSP), a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), etc. The memory unit 12 includes, for example, an internal recording medium or an external recording medium. The internal recording medium includes a non-volatile memory, etc. The external recording medium includes a hard disk (hard disk drive (HDD)), a solid state drive (SSD), an optical disk device, etc. The communication unit 13 includes, for example, a communication circuit or a communication module for transmitting and receiving data with an external device such as a server.

The acquisition unit 100 acquires the resistance value (hereinafter referred to as the resistance value) of the electric heater 21, for example, through the communication unit 13. The resistance value is calculated, for example, based on the voltage at both ends of the electric heater 21 detected by the voltage sensor 26 and the current flowing through the electric heater 21 detected by the inductive flow sensor 27. In this embodiment, in addition to acquiring the resistance value, the acquisition unit 100 acquires the power value (hereinafter referred to as the power value) of the lamp heater 20 and the temperature value (hereinafter referred to as the temperature value) of the lamp heater 20. The power value is calculated, for example, based on the voltage at both ends of the electric heater 21 detected by the voltage sensor 26 and the current flowing through the electric heater 21 detected by the inductive flow sensor 27.

The acquired resistance value and power value may be subjected to low-pass filtering (e.g., moving average processing). The low-pass filtering of the resistance value and power value is set, for example, according to the type of the lamp heater 20, and is performed by the abnormality determination device 10 or an external device.

The temperature value is measured by the temperature sensor 25. The object of the temperature measured by the temperature sensor 25 may be the electric heating element 21, the object to be heated by the electric heating element 21, or the environment around the electric heating element 21. For example, the value measured by the temperature sensor 25 in the form shown below can be set as the "temperature value". · The value obtained by directly measuring the temperature of the electric heating element 21 using the temperature sensor 25. · The value obtained by measuring the surface of the object to be heated (for example, a workpiece or a semiconductor wafer arranged in a frame containing the lamp heater 20) heated by the electric heating element 21 using the temperature sensor 25. · The value obtained by measuring the ambient temperature around the object to be heated heated by the electric heating element 21 arranged in the furnace using the temperature sensor 25.

The determination unit 110 performs an abnormality determination based on the acquired resistance value to determine whether the lamp heater 20 is abnormal. Specifically, when the acquired resistance value exceeds a first critical value, the determination unit 110 determines that the lamp heater 20 is abnormal.

The first critical value is calculated, for example, based on the resistance value (hereinafter referred to as the reference resistance value) when the lamp heater 20 is in a normal and stable state. As an example, the first critical value is calculated by multiplying the reference resistance value by a residual coefficient (for example, 1.05). Whether the lamp heater 20 is normal when the first critical value is calculated is determined, for example, by visual inspection or camera images. The normal state of the lamp heater 20 includes a state in which the lamp heater 20 is not determined to be abnormal by the determination unit 110. The calculation of the first critical value can be performed using the abnormality determination device 10, or can be performed using an external device. Whether the lamp heater 20 is in a stable state is determined, for example, by whether the stability condition described later is satisfied. The calculated first threshold value may be stored in the memory unit 12 or in an external device.

In the present embodiment, the determination unit 110 performs an abnormality determination when the lamp heater 20 is in a stable state. An example of a stable condition for determining that the lamp heater 20 is in a stable state is shown below. Whether the lamp heater 20 is in a stable state can be determined based on any one of the following stable conditions, or can be determined based on any multiple of the following stable conditions or conditions other than the following stable conditions. · The power value is within a predetermined first range throughout the first period. For example, as long as the variation range of the power value in a predetermined monitoring period (e.g., 60 seconds) is within plus or minus 20%, it is determined to be within the first range. The first period is, for example, a period obtained by multiplying the period of obtaining the power value by the moving average number of times of the power value, and is a period longer than the monitoring period (for example, 120 seconds). ·The temperature value is within the predetermined second range throughout the second period. For example, as long as the temperature variation of the lamp heater 20 in the predetermined monitoring period (for example, 60 seconds) is within plus or minus 1 degree Celsius, it is judged to be within the second range. The second period is, for example, a period longer than the monitoring period (for example, 120 seconds).

The following shows an example of determining that "the power value is within the predetermined first range throughout the first period" when moving average processing is performed on the resistance value and the power value. · When the number of moving average processing performed on the power value is greater than the number of moving average processing performed on the resistance value, as long as the power value is continuously within the first range by the number of moving average processing performed on the power value. · When the number of moving average processing performed on the power value is less than the number of moving average processing performed on the resistance value, as long as the power value is continuously within the first range by the number of moving average processing performed on the resistance value, it is determined that "the power value is within the predetermined first range throughout the first period".

When determining whether the lamp heater 20 is in a stable state, the time that has passed since the start of the monitoring period or the first period or the second period is measured by an external device, for example, and is acquired by the acquisition unit 100 via the communication unit 13.

When the obtained resistance value exceeds the first critical value, the determination unit 110 determines whether the abnormality of the lamp heater 20 is caused by "blackening of the lamp heater 20" or "degradation of resistance of the electric heater 21" based on the obtained power value. Specifically, when the obtained power value exceeds the second critical value, the determination unit 110 determines that the abnormality of the lamp heater 20 is caused by "blackening of the lamp heater 20", and when the obtained power value does not exceed the second critical value, the determination unit 110 determines that the abnormality of the lamp heater 20 is caused by "degradation of resistance of the electric heater 21". The "blackening phenomenon of the lamp heater 20" includes, for example, the phenomenon of blackening due to the adhesion of evaporated filaments to the inner surface of the glass tube covering the electric heater 21, and the phenomenon of blackening due to the adhesion of dirt to the outer surface of the glass tube covering the electric heater 21. The "deterioration of the resistance of the electric heater 21" includes the phenomenon of an increase in the resistance value of the electric heater 21 due to changes over the years.

The second critical value is calculated, for example, based on the power value (hereinafter referred to as the reference power value) when the lamp heater 20 is in a normal and stable state. As an example, the second critical value is calculated by multiplying the reference power value by a residual coefficient (for example, 1.1). Whether the lamp heater 20 is normal when the second critical value is calculated is determined, for example, by visual inspection or camera images. The calculation of the second critical value can be performed in the abnormality determination device 10 or in an external device. Whether the lamp heater 20 is in a stable state is determined, for example, by whether the stability condition is met. The calculated second critical value can be stored in the memory unit 12 or in an external device.

When the lamp heater 20 is determined to be abnormal, for example, a notification is made that the lamp heater 20 is suspected to be degraded or the lamp heater 20 is faulty. At this time, the abnormality of the lamp heater 20 may be notified in stages according to the obtained resistance value. For example, when the obtained power value exceeds 103% of the first critical value, the deterioration state of the heater is notified at the "caution" level. When the obtained power value exceeds 105% of the first critical value, the deterioration state of the heater is notified at the "alarm" level.

An example of an abnormality determination method using the abnormality determination device 10 will be described with reference to Fig. 2 to Fig. 4. As an example, the abnormality determination method shown in Fig. 2 to Fig. 4 is implemented by the processor 11 executing a predetermined program.

As shown in FIG2 , when the abnormality determination method is started, the acquisition unit 100 acquires a resistance value (step S1). The determination unit 110 determines whether the acquired resistance value exceeds a first critical value (step S2). If it is determined that the acquired resistance value exceeds the first critical value, the determination unit 110 determines that the lamp heater 20 is abnormal (step S3).

After the lamp heater 20 is determined to be abnormal in step S3, or when it is not determined in step S2 that the acquired resistance value exceeds the first critical value, the determination unit 110 determines whether to terminate the abnormality determination method (step S4). If it is not determined that the abnormality determination method is terminated, the process returns to step S1 to acquire the resistance value.

An example of the termination condition of the abnormality determination method is shown below. · The acquisition unit 100 acquires the termination instruction. · The determination unit 110 performs abnormality determination a predetermined number of times. · A predetermined time has passed since the start of the abnormality determination method.

3, a first example of an abnormality determination method for the case where an abnormality determination is performed when the lamp heater 20 is in a stable state will be described.

As shown in FIG3 , when the abnormality determination method is started, the determination unit 110 determines whether the lamp heater 20 is in a stable state (step S5 ). Step S5 is repeated until it is determined that the lamp heater 20 is in a stable state.

When it is determined that the lamp heater 20 is in a stable state, steps S1 to S4 are executed. If it is not determined in step S4 that the abnormality determination method is terminated, the process returns to step S5 to determine whether the lamp heater 20 is in a stable state.

4, a second example of the abnormality determination method in the case where the abnormality determination is performed when the lamp heater 20 is in a stable state will be described.

As shown in FIG4 , when the abnormality determination method is started, the determination unit 110 determines whether the lamp heater 20 is in a stable state (step S5), and when it is determined that the lamp heater 20 is in a stable state, the acquisition unit 100 acquires the resistance value and the power value (step S6). For example, the power value and the resistance value are acquired at substantially the same timing.

When the resistance value and the power value are obtained, the determination unit 110 determines whether the obtained resistance value exceeds the first critical value (step S2). If it is determined that the obtained resistance value exceeds the first critical value, the determination unit 110 determines whether the obtained power value exceeds the second critical value (step S7).

If it is determined that the acquired power value exceeds the second critical value, the determination unit 110 determines that the lamp heater 20 is abnormal due to the blackening phenomenon of the lamp heater 20 (step S8), and then proceeds to step S4. If it is not determined that the acquired power value exceeds the second critical value, the determination unit 110 determines that the lamp heater 20 is abnormal due to the resistance degradation of the electric heating element 21 (step S9), and then proceeds to step S4.

The abnormality determination device 10 can exert the following effects.

The abnormality determination device 10 includes: an acquisition unit 100, which acquires the resistance value of the electric heater 21 calculated based on the voltage at both ends of the electric heater 21 of the lamp heater 20 and the current flowing through the electric heater 21; and a determination unit 110, which determines whether the lamp heater 20 is abnormal based on the acquired resistance value, i.e., abnormality determination. When the acquired resistance value exceeds the first critical value, the determination unit 110 determines that the lamp heater 20 is abnormal. With such a structure, the possibility of abnormality of the lamp heater 20 can be determined without visual inspection or using a camera image. As a result, an abnormality determination device 10 capable of determining the possibility of abnormality of the lamp heater 20 at a low cost can be realized.

Here, the relationship between the power value of the normal lamp heater 20 and the power value of the abnormal lamp heater 20 is shown in FIG5. In FIG5, the power value of the normal lamp heater 20 is represented by a dotted line, and the power value of the abnormal lamp heater 20 is represented by a solid line. As an example, as shown in FIG6, a lamp heater 20 in a state where the radiant heat 202 directly heating the temperature sensor 25 is reduced due to the blackening phenomenon is set as an abnormal lamp heater 20. In FIG6, the lamp heater 20 has a portion 201 that has become black due to the blackening phenomenon, and heats the object 200 to be heat-treated.

As shown in FIG5 , the power value of the abnormal lamp heater 20 in the stable state increases compared to the normal lamp heater 20. Therefore, by obtaining the power value and comparing it with the first threshold value calculated based on the power value of the normal lamp heater 20, the possibility of abnormality of the lamp heater 20 can be determined. In addition, by performing abnormality determination when the lamp heater 20 is in a stable state, the possibility of abnormality of the lamp heater 20 can be determined more accurately.

When the acquired power value is within the predetermined first range throughout the first period, the determination unit 110 determines that the lamp heater 20 is in a stable state. With this structure, the possibility of abnormality of the lamp heater 20 can be determined more accurately.

When the acquired resistance value exceeds the first critical value, when the acquired power value exceeds the second critical value, the determination unit 110 determines that the abnormality of the lamp heater 20 is caused by the blackening phenomenon of the lamp heater 20. With this structure, the cause of the abnormality of the lamp heater 20 can be determined.

When the acquired resistance value exceeds the first critical value, and the acquired power value does not exceed the second critical value, the determination unit 110 determines that the abnormality of the lamp heater 20 is caused by the degradation of the resistance of the electric heating element 21. With this structure, the cause of the abnormality of the lamp heater 20 can be identified.

The power value is low-pass filtered. This structure makes it easy to stabilize the power value.

When the acquired temperature value is within the predetermined second range throughout the second period, the determination unit 110 determines that the lamp heater 20 is in a stable state. With this structure, the possibility of abnormality of the lamp heater 20 can be determined more accurately.

The abnormality determination system disclosed in the present invention can achieve the following effects.

The abnormality determination system 1 includes an abnormality determination device 10, a lamp heater 20, and a control device for controlling the lamp heater 20. With such a structure, an abnormality determination system capable of determining the possibility of abnormality of the lamp heater at low cost can be realized.

The abnormality determination method disclosed in the present invention can achieve the following effects.

In the abnormality determination method, the resistance value of the electric heater 21 is calculated based on the voltage at both ends of the electric heater 21 of the lamp heater 20 and the current flowing through the electric heater 21. When the obtained resistance value exceeds the first critical value, it is determined that the lamp heater 20 is abnormal. With this structure, the possibility of abnormality of the lamp heater can be determined at a low cost.

The abnormality determination device 10, the abnormality determination system 1, and the abnormality determination method may also be configured as follows.

The acquisition unit 100 only needs to be configured to at least acquire a resistance value.

The determination unit 110 only needs to be configured to be able to determine that the lamp heater 20 is abnormal when at least the acquired resistance value exceeds the first critical value.

The control device is not limited to the case where it includes the thermostat 22, and for example, as shown in FIG7 , it may also include a power regulator 28. Compared with the abnormality determination system 1 of FIG1 , the abnormality determination system 1 of FIG7 includes a power regulator 28 instead of the temperature sensor 25, the thermostat 22, and the solid-state relay 23. That is, in the abnormality determination system 1 of FIG7 , the temperature value of the lamp heater 20 is not controlled. The power regulator 28 controls the effective voltage supplied to the lamp heater 20 to a predetermined value. Thereby, the design freedom of the abnormality determination system 1 can be improved.

As shown in Fig. 8, the determination unit 110 may determine that the lamp heater 20 is abnormal even if the lamp heater 20 is not determined to be in a stable state based on the power value. As an example, the stable state determination process shown in Fig. 8 is implemented by the processor 11 executing a predetermined program.

As shown in FIG8 , when the stable state determination process starts, the acquisition unit 100 acquires the temperature value (step S10). The determination unit 110 determines whether the acquired temperature value is within the second range throughout the second period, in other words, whether the second period satisfies "lower limit value ≦ temperature value ≦ upper limit value" (step S11). Step S11 is repeated until it is determined that the second period satisfies "lower limit value ≦ temperature value ≦ upper limit value".

When it is determined that "lower limit value ≦ temperature value ≦ upper limit value" is satisfied throughout the second period, the acquisition unit 100 acquires the power value (step S12). The determination unit 110 determines whether the acquired power value is within the first range throughout the first period, in other words, whether "lower limit value ≦ power value ≦ upper limit value" is satisfied throughout the first period (step S13). As an example, when the reference power value is 1000 W, the lower limit value is 80% (=800 W) of the reference power value, and the upper limit value is 120% (=1200 W) of the reference power value.

If it is determined that the acquired power value is within the first range throughout the first period, the determination unit 110 determines that the lamp heater 20 is in a stable state (step S14), and the stable state determination process is terminated. If it is not determined that the acquired power value is within the first range throughout the first period, the determination unit 110 determines that the lamp heater 20 is abnormal (step S15), and the stable state determination process is terminated.

The determination unit 110 may be configured to determine that the lamp heater 20 is abnormal if it is not determined that the acquired power value is within the first range for a plurality of consecutive times in step S15.

The abnormality determination method disclosed herein can be executed by a computer. That is, the disclosure includes a program for causing a computer to execute the abnormality determination method and a computer-readable storage medium storing the program for causing a computer to execute the abnormality determination method.

In the above, various embodiments of the present disclosure are described in detail with reference to the drawings, and finally various forms of the present disclosure are described. In addition, in the following description, reference symbols are also added as an example.

The first form of the abnormality determination device 10 disclosed herein includes: An acquisition unit 100, which acquires the resistance value of the electric heater of the lamp heater calculated based on the voltage at both ends of the electric heater and the current flowing through the electric heater; and A determination unit 110, which determines whether the lamp heater is abnormal based on the acquired resistance value, i.e., abnormality determination. The determination unit 110 determines that the lamp heater is abnormal when the acquired resistance value exceeds a first critical value.

In the second form of the abnormality determination device 10 disclosed herein, the determination unit 110 performs the abnormality determination when the lamp heater is in a stable state.

In the third form of the abnormality determination device 10 disclosed herein, the acquisition unit 100 acquires the power value of the electric heater, and when the acquired power value is within a predetermined first range over a first period, the determination unit 110 determines that the lamp heater is in a stable state.

In the fourth form of the abnormality determination device 10 disclosed herein, when the obtained resistance value exceeds the first critical value, and when the obtained power value exceeds the second critical value, the determination unit 110 determines that the abnormality of the lamp heater is caused by the blackening phenomenon of the lamp heater.

In the abnormality determination device 10 of the fifth form of the present disclosure, when the obtained resistance value exceeds the first critical value, and the obtained power value does not exceed the second critical value, the determination unit 110 determines that the abnormality of the lamp heater is caused by the degradation of the resistance of the electric heating element.

In the sixth form of the abnormality determination device 10 disclosed herein, a low-pass filtering process is performed on the power value.

In the seventh form of the abnormality determination device 10 disclosed herein, the acquisition unit 100 acquires the temperature value of the lamp heater, and the determination unit 110 determines that the lamp heater is in a stable state when the acquired temperature value is within a predetermined second range throughout the second period.

The eighth form of abnormality determination system 1 disclosed herein comprises: the abnormality determination device 10 of the form; the lamp heater 20; and a control device for controlling the lamp heater 20.

In the ninth form of the abnormality determination system 1 disclosed herein, the control device controls the temperature value of the lamp heater 20 to a predetermined value.

In the tenth form of the abnormality determination system disclosed herein, the control device controls the effective voltage supplied to the lamp heater 20 to a predetermined value.

In the eleventh form of the abnormality determination method disclosed herein, the resistance value of the electric heater of the lamp heater is calculated based on the voltage at both ends of the electric heater and the current flowing through the electric heater, and when the obtained resistance value exceeds the first critical value, the lamp heater is determined to be abnormal.

By appropriately combining any of the various embodiments or modifications, the effects of each embodiment or modification can be achieved. In addition, embodiments can be combined with each other, embodiments can be combined with each other, or embodiments can be combined with embodiments, and different embodiments or features in embodiments can be combined with each other.

This disclosure has been fully described in relation to the preferred embodiment with reference to the accompanying drawings, but various modifications or alterations are obvious to those skilled in the art. It should be understood that such modifications or alterations are included within the scope of this disclosure based on the accompanying claims as long as they do not depart from the scope of this disclosure. [Industrial Applicability]

The abnormality determination device, abnormality determination system and abnormality determination method disclosed herein can be applied to, for example, a halogen heater.

1: Abnormality determination system 10: Abnormality determination device 11: Processor 12: Memory unit 13: Communication unit 20: Lamp heater 21: Electric heating element 22: Thermostat 23: SSR 24: Power supply 25: Temperature sensor 26: Voltage sensor 27: Current sensor 28: Power regulator 100: Acquisition unit 110: Determination unit 200: Heat-treated object 201: Part that turns black due to the blackening phenomenon 202: Radiant heat S1 to S15: Steps

FIG. 1 is a block diagram showing an abnormality determination system including an abnormality determination device according to an embodiment of the present disclosure. FIG. 2 is a first flowchart for explaining an abnormality determination method using the abnormality determination device of FIG. 1 . FIG. 3 is a second flowchart for explaining an abnormality determination method using the abnormality determination device of FIG. 1 . FIG. 4 is a third flowchart for explaining an abnormality determination method using the abnormality determination device of FIG. 1 . FIG. 5 is a graph showing a relationship between a power value of a normal lamp heater and a power value of an abnormal lamp heater. FIG. 6 is a schematic diagram showing an example of an abnormal lamp heater. FIG. 7 is a block diagram showing a modified example of the abnormality determination system of FIG. 1 . FIG. 8 is a flowchart for explaining a stable state determination process using the abnormality determination device of FIG. 1 .

S1~S4: Steps

Claims (10)

An abnormality determination device includes: an acquisition unit that acquires the resistance value of the electric heater of a lamp heater calculated based on the voltage at both ends of the electric heater and the current flowing through the electric heater, and acquires the power value of the electric heater; and a determination unit that performs abnormality determination based on the acquired resistance value, wherein the abnormality determination is a determination of whether the lamp heater is abnormal. When the obtained resistance value exceeds the first critical value, the determination unit determines that the lamp heater is abnormal. When the obtained resistance value exceeds the first critical value, when the obtained power value exceeds the second critical value, the determination unit determines that the abnormality of the lamp heater is caused by the blackening phenomenon of the lamp heater. The abnormality determination device as described in claim 1, wherein the determination unit performs the abnormality determination when the lamp heater is in a stable state. The abnormality determination device as described in claim 2, wherein when the power value obtained is within a predetermined first range throughout the first period, the determination unit determines that the lamp heater is in a stable state. The abnormality determination device as described in claim 2 or 3, wherein when the obtained resistance value exceeds the first critical value, and when the obtained power value does not exceed the second critical value, the determination unit determines that the abnormality of the lamp heater is caused by the deterioration of the resistance of the electric heating element. An abnormality determination device as described in claim 2 or 3, wherein a low-pass filtering process is performed on the power value. An abnormality determination device as described in claim 2 or 3, wherein the acquisition unit acquires the temperature value of the lamp heater, and when the acquired temperature value is within a predetermined second range throughout the second period, the determination unit determines that the lamp heater is in a stable state. An abnormality determination system, comprising: an abnormality determination device as described in any one of claims 1 to 6; the lamp heater; and a control device for controlling the lamp heater. An abnormality determination system as described in claim 7, wherein the control device controls the temperature value of the lamp heater to a predetermined value. An abnormality determination system as described in claim 7, wherein the control device controls the effective voltage supplied to the lamp heater to a predetermined value. A method for determining an abnormality, obtaining the resistance value of the electric heater of a lamp heater calculated based on the voltage at both ends of the electric heater and the current flowing through the electric heater, and obtaining the power value of the electric heater, and determining that the lamp heater is abnormal due to the blackening phenomenon of the lamp heater when the obtained resistance value exceeds a first critical value and when the obtained power value exceeds a second critical value.