Demisting system

Abstract

A defog system includes: a vehicle speed sensor configured to detect a vehicle speed; a first heater arranged outside a field of view of an imaging device and configured to heat a window; a second heater arranged within the field of view of the imaging device and arranged to contact the window and configured to heat the window; and a controller configured to control the first heater and the second heater. The controller is configured to determine whether the vehicle is stopped based on a detection result of the vehicle speed sensor, start the first heater and the second heater if a first condition is met, the first condition including a condition that the vehicle is stopped, and start only the first heater if a second condition is met, the second condition including a condition that the vehicle is traveling.

Description

Technical Field

[0001] The present invention relates to a defogging system for defogging windows of a vehicle. Background Art

[0002] Typically, a vehicle includes an imaging device that captures the exterior space of the vehicle from the interior space of the vehicle through a window. Such a vehicle may include a defogging system for defogging the windows. Such a defogging system includes, for example, a heater that heats the window and a controller that controls the heater.

[0003] For example, JP2020-152324A discloses a mobile body, which includes: a monitoring device that monitors the surrounding environment of the mobile body through a transparent window; a heating device that heats a portion of the window within a monitoring area of ​​the monitoring device; an air conditioner that performs air conditioning on an interior space of the mobile body; and a controller that controls the drive of the heating device and the air conditioner.

[0004] In the above-mentioned defog system, when a direct heating type heater (i.e., a heater in contact with the window) arranged within the field of view of the imaging device heats the window, thermal distortion may occur in the window within the field of view of the imaging device, which may distort the image captured by the imaging device. In particular, when the vehicle is traveling, the image captured by the imaging device is required to have high accuracy, so it is preferable to suppress the above-mentioned distortion of the image. Summary of the invention

[0005] In view of the above background, an object of the present invention is to provide a defog system that can effectively defog a window while effectively suppressing distortion of an image captured by an imaging device while a vehicle is traveling.

[0006] To achieve such an object, one aspect of the present invention provides a defogger system (X) installed in a vehicle (1) including an imaging device (10), the imaging device (10) being configured to photograph an exterior space (SP2) of the vehicle from an interior space (SP1) of the vehicle through a window (6), the defogger system comprising: a vehicle speed sensor (44) configured to detect a vehicle speed; a first heater (28) arranged outside the field of view of the imaging device and configured to heat the window; a second heater (29) arranged within the field of view of the imaging device and arranged to contact the window and configured to heat the window; and and a controller (26) configured to control the first heater and the second heater, wherein the controller is configured to determine whether the vehicle is stopped based on the detection result of the vehicle speed sensor, start the first heater and the second heater (S5, S15, S25, S35) when a first condition is met, the first condition including the condition that the vehicle is stopped (S4, S14, S24, S34: yes), and start only the first heater (S6, S17, S29, S39) when a second condition is met, the second condition including the condition that the vehicle is moving (S4, S14, S24, S34: no).

[0007] According to this aspect, when the vehicle is stopped, the vehicle windows can be effectively defogged by activating the first heater and the second heater. On the other hand, when the vehicle is traveling, the occurrence of thermal distortion in the window within the field of view of the imaging device can be suppressed by activating only the first heater. Therefore, the occurrence of distortion in the image captured by the imaging device can be effectively suppressed.

[0008] In the above aspect, preferably, the first condition includes a condition that the vehicle is stopped or a condition that the vehicle is traveling at a speed equal to or higher than a prescribed reference speed (S16: Yes), and the second condition includes a condition that the vehicle is traveling at a speed lower than the reference speed (S16: No).

[0009] When the vehicle is traveling at a relatively high speed, the traveling wind (i.e., the wind generated by the traveling of the vehicle) cools the vehicle windows. Therefore, even if the second heater is activated, thermal distortion is unlikely to occur in the windows within the field of view of the imaging device. According to the above aspects, in consideration of the above possibilities, activation of the second heater is allowed when the vehicle is traveling at a relatively high speed. Therefore, the windows can be defogged more effectively.

[0010] In the above aspect, preferably, the demisting system further includes a heater temperature sensor (45) configured to detect the temperature of the second heater, wherein the first condition includes a condition that the temperature of the second heater is equal to or lower than a prescribed threshold temperature (S28: Yes).

[0011] According to this aspect, the activation of the second heater can be suppressed when the temperature of the second heater is relatively high. Therefore, the occurrence of thermal distortion in the window within the field of view of the imaging device can be suppressed more effectively.

[0012] In the above aspect, preferably, the defog system also includes a window temperature sensor (46), which is configured to detect the temperature of the part within the field of view of the window, which is the part within the field of view of the imaging device, and the first condition includes the condition that the temperature of the part within the field of view of the window is equal to or lower than a specified threshold temperature (S38: yes).

[0013] According to this aspect, the activation of the second heater can be suppressed when the temperature of the portion within the field of view of the window (the portion within the field of view of the imaging device) is relatively high. Therefore, the occurrence of thermal distortion in the window within the field of view of the imaging device can be more effectively suppressed.

[0014] In the above aspect, preferably, the defog system also includes an external temperature sensor (43), which is configured to detect the temperature of the external space of the vehicle, wherein the first condition and the second condition each include a condition that the temperature of the external space of the vehicle is lower than a prescribed reference temperature (S2, S12, S22, S32: yes).

[0015] According to this aspect, it is possible to suppress activation of the first heater and / or the second heater in a state where the temperature outside the vehicle is relatively high and the vehicle window is not easily fogged. Therefore, the energy saving performance of the defogger system can be improved.

[0016] In the above aspect, preferably, the first heater is in contact with the window.

[0017] According to this aspect, both the first heater and the second heater can directly heat the window, thereby increasing the temperature increase rate of the window. Therefore, the window can be defogged more effectively and power consumption can be reduced.

[0018] In the above aspect, preferably, the first heater faces the window at a certain interval.

[0019] According to this aspect, when the first heater fails, the first heater can be easily removed, thereby improving the maintainability of the first heater.

[0020] In the above aspect, preferably, when the vehicle is traveling, the controller performs traveling control of the vehicle based on an image captured by the imaging device.

[0021] According to this aspect, when the vehicle is traveling, traveling control of the vehicle can be performed based on the undistorted image.

[0022] Therefore, according to the above aspects, it is possible to provide a defogging system that can effectively defog a window while effectively suppressing distortion of an image captured by an imaging device while a vehicle is traveling. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a perspective view showing a vehicle according to a first embodiment of the present invention;

[0024] Figure 2 is a cross-sectional view showing a front window and its periphery according to a first embodiment of the present invention;

[0025] Figure 3 is a front view showing a front window and a heating device according to a first embodiment of the present invention;

[0026] Figure 4 is a block diagram showing a vehicle according to a first embodiment of the present invention;

[0027] Figure 5 is a flowchart showing the demisting control according to the first embodiment of the present invention;

[0028] Figure 6 is a cross-sectional view showing a front window and its periphery according to a modified example of the present invention;

[0029] Figure 7 is a front view showing a front window and a heating device according to a modified example of the present invention;

[0030] Figure 8 is a sectional view showing a front window and its periphery according to another modification of the present invention;

[0031] Fig. 9 is a flowchart showing a demisting control according to a second embodiment of the present invention;

[0032] Fig.10 is a flowchart showing a demisting control according to a third embodiment of the present invention; and

[0033] Fig.11 is a flowchart showing the defog control according to the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0034] <<First Embodiment>>

[0035] Below, refer to Figures 1 to 5 A first embodiment of the present invention is described.

[0036] <Vehicle 1>

[0037] First, refer to Figures 1 to 4 A vehicle 1 according to a first embodiment of the present invention is described.

[0038] Reference Figure 1 According to the present embodiment, the vehicle 1 includes an automobile. The vehicle 1 includes a vehicle body 2 that is elongated in the front-rear direction. In the vehicle body 2, an interior space SP1 of the vehicle 1 (hereinafter referred to as the interior space SP1) is formed. A compartment 3 for accommodating passengers is provided in the front-rear center portion of the interior space SP1. The compartment 3 is provided with, for example, a plurality of front seats 4 (driver's seat and passenger seat) and a plurality of rear seats 5 arranged behind the front seats 4. In the present embodiment, two rows of seats are provided in the front and rear. In another embodiment, only one row of seats may be provided, or three or more rows of seats may be provided in the front and rear.

[0039] In the front part of the vehicle body 2, a front window 6 (windshield: an example of a window) is provided in front of the front seat 4. The front window 6 is made of glass. In another embodiment, the front window 6 may be made of a transparent material other than glass (e.g., a transparent resin). In the rear part of the vehicle body 2, a rear window 7 is provided behind the rear seat 5. On both lateral sides of the vehicle body 2, a plurality of side doors 8 are provided on both lateral sides of the front seat 4 and the rear seat 5. A side window 9 is provided at the upper part of each side door 8.

[0040] Reference Figure 1 and Figure 2 , a front camera 10 (an example of an imaging device) is provided behind the upper portion of the front window 6. The front camera 10 is a device configured to photograph the external space SP2 of the vehicle 1 (in the present embodiment, the space in front of the vehicle 1: hereinafter referred to as "external space SP2") from the internal space SP1 through the front window 6. The front camera 10 is composed of, for example, a digital camera using a solid-state imaging element such as a CCD and a CMOS. The front camera 10 includes a lens configured to converge light from the front through the front window 6, and a sensor configured to convert the light converged by the lens into an electrical signal. Figure 2 The arrow P in represents the field of view (image capturing range) of the front camera 10. Figure 3 The dotted frame Q in shows the portion of the front window 6 within the field of view of the front camera 10 (hereinafter referred to as “the portion Q within the field of view”).

[0041] Reference Figure 2 , the front camera 10 is attached to the inner surface of the front window 6 by a bracket 11. The bracket 11 includes a main body 12 arranged around the front camera 10 and a hood 13 extending forward from the main body 12. The main body 12 is fixed to the inner surface of the front window 6. The hood 13 surrounds the space in front of the lens of the front camera 10 together with the front window 6. The hood 13 includes a bottom wall 13A extending in the lateral direction, and left and right side walls 13B extending upward from both lateral ends of the bottom wall 13A (in the left side wall 13A and the right side wall 13B extending upward from ... Figure 2 In the figure, only the right side wall 13B is shown.

[0042] Reference Figure 4 The vehicle 1 includes a powertrain 14, a brake device 15, a steering device 16, a human-machine interface 17 (HMI), a navigation device 18, a heating device 19, an air conditioner 20, an occupant sensor 21, an external environment sensor 22, a vehicle sensor 23 and a controller 26. The heating device 19, the air conditioner 20, the occupant sensor 21, the external environment sensor 22, the vehicle sensor 23 and the controller 26 constitute a defog system X.

[0043] The power system 14 is a device configured to apply driving force to the vehicle 1. The power system 14 includes, for example, an internal combustion engine (for example, a gasoline engine or a diesel engine) and / or an electric motor.

[0044] The brake device 15 is a device configured to apply a braking force to the vehicle 1. The brake device 15 includes, for example, a brake caliper configured to press a pad against a brake rotor and an electric cylinder configured to supply oil pressure to the brake caliper.

[0045] The steering device 16 is a device configured to change the steering angle of the wheels. The steering device 16 includes, for example, a rack-and-pinion mechanism configured to steer the wheels and an electric motor configured to drive the rack-and-pinion mechanism.

[0046] The HMI 17 is a device configured to notify the occupant of various information (for example, a failure of the heating device 19) and receive input operations of the occupant. The HMI 17 includes, for example, a touch panel, a sound generator, an ignition switch, and the like.

[0047] The navigation device 18 is a device configured to provide the occupant with route guidance to the destination of the vehicle 1, etc. The navigation device 18 includes an input device configured to receive an input operation of the occupant. The input device may be composed of a part of the HMI 17, or may be provided separately from the HMI 17. The navigation device 18 stores map information. The navigation device 18 recognizes the current position (latitude and longitude) of the vehicle 1 based on a signal received from an artificial satellite. The navigation device 18 sets a route from a departure point (e.g., current position) to the destination of the vehicle 1 based on the destination of the vehicle 1 input by the occupant to the above-mentioned input device, the map information, and the current position of the vehicle 1.

[0048] The heating device 19 is a device configured to defog the front window 6 by heating the front window 6. Figure 2 and 3 The heating device 19 includes a first heater 28 and a second heater 29 .

[0049] The first heater 28 of the heating device 19 is arranged outside the field of view of the front camera 10. The first heater 28 includes, for example, a metal heating wire 31 arranged in contact with the inner surface of the front window 6 and a pair of electrodes (not shown) connected to the heating wire 31. The heating wire 31 is printed on the front window 6. The heating wire 31 has a frame-like shape (annular shape) and surrounds the inner part Q of the field of view of the front window 6. In another embodiment, the heating wire 31 may be set inside the front window 6, or may have a laminated structure. In addition, in another embodiment, a plurality of heating wires 31 may be arranged, or the heating wire 31 may have a shape other than the frame-like shape (for example, a linear shape).

[0050] The second heater 29 of the heating device 19 is arranged in the field of view of the front camera 10. For example, the second heater 29 includes a plurality of metal heating wires 32 arranged to contact the inner surface of the front window 6, and a pair of electrodes 33 connected to both ends of each heating wire 32. Each heating wire 32 is printed on the front window 6. Each heating wire 32 has a linear shape and extends in the lateral direction. In another embodiment, each heating wire 32 may be arranged in the front window 6, or may have a laminated structure. In addition, in yet another embodiment, only one heating wire 32 may be arranged, or each heating wire 32 may have a shape different from a linear shape (e.g., a frame-like shape). In addition, in yet another embodiment, the second heater 29 may include a heating wire 32 arranged in a single stroke manner so that both ends of a heating wire 32 are adjacent to each other.

[0051] Reference Figure 4 The air conditioner 20 is a device configured to perform air conditioning on the interior space SP1. The air conditioner 20 includes a duct connected to the interior space SP1 and the exterior space SP2, an evaporator and a heater core both installed in the duct, a blower (fan) configured to generate airflow in the duct, and a motor configured to drive the blower. The air conditioner 20 is configured to be able to switch the air volume (rotation speed of the blower) and the air conditioning mode. The above-mentioned air conditioning mode includes, for example, an external air introduction mode for introducing air in the exterior space SP2 into the interior space SP1, an internal air circulation mode for circulating the air in the interior space SP1, and a defroster mode for blowing air to the front window 6.

[0052] The occupant sensor 21 is a sensor configured to detect the seating state of the occupant. The occupant sensor 21 includes a seat belt sensor 35 configured to detect the fastening state of the seat belt by the occupant and an occupant camera 36 configured to photograph the occupant.

[0053] The external environment sensor 22 is a sensor configured to detect objects present in the external space SP2, such as boundaries and obstacles on the travel route of the vehicle 1. The external environment sensor 22 includes the above-mentioned front camera 10, sonar 38, and external camera 39.

[0054] The vehicle sensor 23 is a sensor configured to detect the state of the interior space SP1, the state of the exterior space SP2, the driving state of the vehicle 1, and the like. The vehicle sensor 23 includes: an interior temperature sensor 41 configured to detect the temperature of the interior space SP1 (hereinafter referred to as "the interior temperature"); an interior humidity sensor 42 configured to detect the humidity of the interior space SP1 (hereinafter referred to as "the interior humidity"); an exterior temperature sensor 43 configured to detect the temperature of the exterior space SP2 (hereinafter referred to as "the exterior temperature"); a vehicle speed sensor 44 configured to detect the vehicle speed; a heater temperature sensor 45 configured to detect the temperature of the second heater 29; and a window temperature sensor 46 configured to detect the temperature of the portion Q within the field of view of the front window 6. The heater temperature sensor 45 detects the temperature of the second heater 29, for example, based on the resistance value of each heater wire 32 of the second heater 29. The window temperature sensor 46 is composed of, for example, a contact type or non-contact type thermistor.

[0055] The controller 26 includes an electronic control unit composed of a CPU, ROM, RAM, etc. The controller 26 is connected to each component of the vehicle 1 via a communication network such as a controller area network (CAN), and is configured to control each component of the vehicle 1 .

[0056] The controller 26 includes an external environment recognition unit 52 , a travel control unit 53 , a defog control unit 54 , and a storage unit 55 .

[0057] The external environment recognition unit 52 of the controller 26 is configured to recognize the position of an object (e.g., a boundary line and an obstacle on the driving route of the vehicle 1) existing in the external space SP2 based on the detection result of the external environment sensor 22. For example, the external environment recognition unit 52 is configured to recognize the position of an object existing in front of the vehicle 1 by analyzing the change in the density value of the image captured by the front camera 10.

[0058] The driving control unit 53 of the controller 26 is configured to perform driving control of the vehicle 1 based on the detection results of the external environment sensor 22 and the vehicle sensor 23. For example, in a case where the vehicle speed detected by the vehicle speed sensor 44 is equal to or higher than a prescribed first threshold speed, the driving control unit 53 performs lane keeping control based on the position of the dividing line identified by the external environment recognition unit 52. In the lane keeping control, the driving control unit 53 controls the steering device 16 so that the vehicle 1 travels in a reference position (e.g., the lateral center of the lane) in the lane demarcated by the dividing line. In addition, in a case where the vehicle speed detected by the vehicle speed sensor 44 is equal to or higher than a prescribed second threshold speed, the driving control unit 53 performs collision mitigation control based on the position of the obstacle identified by the external environment recognition unit 52. In the collision mitigation control, the driving control unit 53 controls the braking device 15 to avoid or mitigate the collision between the vehicle 1 and the obstacle.

[0059] The defog control unit 54 of the controller 26 is configured to control the heating device 19 to defog the front window 6. In addition, the defog control unit 54 switches the air volume and air conditioning mode of the air conditioner 20 based on the detection result of the vehicle sensor 23 and the input operation of the occupant to the HMI 17. The defog control unit 54 is configured to control the first heater 28 and the second heater 29 of the heating device 19 by using pulse width modulation control (PWM control) based on the detection result of the vehicle sensor 23, etc.

[0060] The storage unit 55 of the controller 26 is composed of a memory, a HDD, etc. The storage unit 55 stores programs, tables, etc. required for controlling the vehicle 1 .

[0061] <Defog control>

[0062] Next, we will refer to Figure 5 The defog control performed by the defog control unit 54 of the controller 26 is described. For example, the defog control is periodically performed from the time immediately after the ignition switch of the vehicle 1 is turned on.

[0063] When the defog control is started, the defog control unit 54 acquires the outside temperature based on the detection result of the outside temperature sensor 43 (step S1 ).

[0064] Subsequently, the demisting control unit 54 determines whether the external temperature is lower than a prescribed reference temperature (10° C. in the present embodiment) (step S2). In another embodiment, the reference temperature may be a temperature different from 10° C. In the case where the external temperature is equal to or higher than the reference temperature (step S2: No), the demisting control unit 54 terminates the demisting control without activating the first heater 28 and the second heater 29.

[0065] On the other hand, in a case where the outside temperature is lower than the reference temperature (step S2 : Yes), the defog control unit 54 acquires the vehicle speed based on the detection result of the vehicle speed sensor 44 (step S3 ).

[0066] Subsequently, the defog control unit 54 determines whether the vehicle speed is 0 km / h, that is, whether the vehicle 1 is stopped (step S4 ).

[0067] In the case where the vehicle 1 stops (step S4: Yes), the defog control unit 54 activates the first heater 28 and the second heater 29 (step S5). Therefore, the front window 6 is heated by the first heater 28 and the second heater 29, so the front window 6 is defogged. In this way, the first condition (i.e., the condition for activating the first heater 28 and the second heater 29) includes two conditions: the condition that the outside temperature is lower than the reference temperature and the condition that the vehicle 1 stops.

[0068] On the other hand, when the vehicle 1 is not stopped, that is, when the vehicle 1 is running (step S4: No), the defog control unit 54 activates only the first heater 28 (step S6). Therefore, the front window 6 is heated by the first heater 28, and thus the front window 6 is defogged. In this way, the second condition (that is, the condition for activating only the first heater 28) includes two conditions, the condition that the outside temperature is lower than the reference temperature and the condition that the vehicle 1 is running.

[0069] In this way, the defog control unit 54 is configured to activate the first heater 28 and the second heater 29 when the first condition including the condition that the vehicle 1 is stopped is satisfied, and to activate only the first heater 28 when the second condition including the condition that the vehicle 1 is traveling is satisfied. Therefore, when the vehicle 1 is stopped, the front window 6 can be effectively defogged by activating the first heater 28 and the second heater 29. On the other hand, when the vehicle 1 is traveling, by activating only the first heater 28, the occurrence of thermal distortion of the front window 6 within the field of view of the front camera 10 can be suppressed. Therefore, the occurrence of distortion in the image captured by the front camera 10 can be effectively suppressed.

[0070] In addition, the first condition (i.e., the condition for activating the first heater 28 and the second heater 29) and the second condition (i.e., the condition for activating only the first heater 28) each include a condition that the outside temperature is lower than the reference temperature. Therefore, it is possible to suppress activation of the first heater 28 and / or the second heater 29 in a state where the outside temperature is high and thus the front window 6 is not prone to fogging. Therefore, it is possible to improve the energy-saving performance of the defogging system X.

[0071] Furthermore, the first heater 28 is in contact with the front window 6. Therefore, both the first heater 28 and the second heater 29 can directly heat the front window 6, thereby increasing the temperature increase rate of the front window 6. Therefore, the front window 6 can be defogged more effectively and power consumption can be reduced.

[0072] Furthermore, the defog control unit 54 suppresses distortion of the image captured by the front camera 10 when the vehicle 1 is traveling. Therefore, when the vehicle 1 is traveling, the traveling control unit 53 can perform traveling control of the vehicle 1 based on the undistorted image.

[0073] <Modification example>

[0074] In this embodiment, the first heater 28 and the second heater 29 include a heating wire 31 and a heating wire 32, respectively. On the other hand, in a modified example, as Figure 6 and Figure 7 As shown, each of the first heater 28 and the second heater 29 may be made of a transparent film such as an indium tin oxide film (ITO film).

[0075] In the present embodiment, the first heater 28 is constituted by a direct heating type heater (a heater arranged to be in contact with the front window 6). On the other hand, in another modified example, as Figure 8 As shown, the first heater 28 may include an indirect heating type heater (a heater facing the front window 6 at a certain interval).

[0076] In the case where the first heater 28 is constituted by an indirect heating type heater, the first heater 28 includes, for example, one or more heating wires (not shown), and is held by the bracket 11. In the case where the first heater 28 is held by the bracket 11 in this manner, the first heater 28 may be detachable together with a portion of the bracket 11. Therefore, the maintainability of the first heater 28 is improved.

[0077] Incidentally, on the upper surface of the bottom wall 13A of the cover 13 constituting the bracket 11, a stray light reducing structure (e.g., a corrugated structure) may be formed to reduce stray light (reflected light) entering the lens of the front camera 10. In this case, the first heater 28 may be attached to the lower surface of the bottom wall 13A (see FIG. Figure 8 ). On the other hand, in the case where the first heater 28 itself is provided with a stray light reducing structure, the first heater 28 may be attached to the upper surface of the bottom wall 13A.

[0078] <<Second Embodiment>>

[0079] Next, we will refer to Fig. 9A second embodiment of the present invention is described. The contents other than the defogging control performed by the defogging control unit 54 are the same as those of the first embodiment. Therefore, the description thereof will be omitted. In addition, steps S11 to S15 of the defogging control according to the second embodiment are the same as steps S1 to S5 of the defogging control according to the first embodiment. Therefore, the description thereof will be omitted.

[0080] When the vehicle 1 is not stopped, that is, when the vehicle 1 is running (step S14: No), the defogger control unit 54 determines whether the vehicle speed is equal to or higher than a prescribed reference speed (80 km / h in this embodiment) (step S16). In another embodiment, the reference speed may be set to a speed other than 80 km / h.

[0081] When the vehicle speed is equal to or higher than the reference speed (step S16: Yes), the defogger control unit 54 activates the first heater 28 and the second heater 29 (step S15). On the other hand, when the vehicle speed is lower than the reference speed (step S16: No), the defogger control unit 54 activates only the first heater 28 (step S17).

[0082] As described above, in the second embodiment, the first condition (i.e., the condition for starting the first heater 28 and the second heater 29) includes the condition that the vehicle 1 is stopped or the condition that the vehicle 1 is traveling at a speed equal to or higher than the reference speed, and the second condition (i.e., the condition for starting only the first heater 28) includes the condition that the vehicle 1 is traveling at a speed lower than the reference speed.

[0083] When the vehicle 1 travels at a relatively high speed, the traveling wind (i.e., wind generated by the travel of the vehicle 1) cools the front window 6. Therefore, even if the second heater 29 is activated, thermal distortion is unlikely to occur in the front window 6 within the field of view of the front camera 10. In the second embodiment, in consideration of the above possibility, activation of the second heater 29 is permitted when the vehicle 1 travels at a relatively high speed. Therefore, the front window 6 can be defogged more effectively.

[0084] <<Third Embodiment>>

[0085] Next, we will refer to Fig.10 A third embodiment of the present invention is described. The contents other than the demisting control performed by the demisting control unit 54 are the same as those of the first embodiment. Therefore, the description thereof will be omitted. In addition, steps S21 to S26 of the demisting control according to the third embodiment are the same as steps S11 to S16 of the demisting control according to the second embodiment. Therefore, the description thereof will be omitted.

[0086] When the vehicle speed is equal to or higher than the reference speed (step S26 : Yes), the defog control unit 54 acquires the temperature of the second heater 29 (hereinafter referred to as “heater temperature”) based on the detection result of the heater temperature sensor 45 (step S27 ).

[0087] Next, the defog control unit 54 determines whether the heater temperature is equal to or less than a prescribed threshold temperature (80° C. in this embodiment) (step S28 ). In another embodiment, the threshold temperature may be a temperature other than 80° C.

[0088] When the heater temperature is equal to or less than the threshold temperature (step S28: Yes), the demisting control unit 54 activates the first heater 28 and the second heater 29 (step S25). On the other hand, when the heater temperature is higher than the threshold temperature (step S28: No), the demisting control unit 54 activates only the first heater 28 (step S29).

[0089] As described above, in the third embodiment, the first condition (i.e., the condition for starting the first heater 28 and the second heater 29) includes the condition that the heater temperature is equal to or lower than the threshold temperature. Therefore, the operation of the second heater 29 can be suppressed in a state where the temperature of the second heater 29 is relatively high. Therefore, the occurrence of thermal distortion in the front window 6 within the field of view of the front camera 10 can be more effectively suppressed.

[0090] In the third embodiment, when the vehicle speed is equal to or higher than the reference speed, the defogger control unit 54 determines whether the heater temperature is equal to or lower than a prescribed threshold temperature. On the other hand, in another embodiment, when the vehicle speed is equal to or higher than the reference speed, the defogger control unit 54 may activate the first heater 28 and the second heater 29. In addition, when the vehicle speed is lower than the reference speed, the defogger control unit 54 may also determine whether the heater temperature is equal to or lower than a prescribed threshold temperature.

[0091] <<Fourth Embodiment>>

[0092] Next, we will refer to Fig.11 A fourth embodiment of the present invention is described. The contents other than the defogging control performed by the defogging control unit 54 are the same as those of the first embodiment. Therefore, the description thereof will be omitted. In addition, steps S31 to S36 of the defogging control according to the fourth embodiment are the same as steps S11 to S16 of the defogging control according to the second embodiment. Therefore, the description thereof will be omitted.

[0093] When the vehicle speed is equal to or greater than the reference speed (step S36: Yes), the defog control unit 54 obtains the temperature of the field-of-view portion Q of the front window 6 (hereinafter referred to as "field-of-view temperature") based on the detection result of the window temperature sensor 46 (step S37).

[0094] Then, the defog control unit 54 determines whether the temperature in the field of view of the front window 6 is equal to or less than a prescribed threshold temperature (80° C. in this embodiment) (step S38). In another embodiment, the threshold temperature may be a temperature other than 80° C.

[0095] When the temperature in the field of view of the front window 6 is equal to or lower than the threshold temperature (step S38: Yes), the defogging control unit 54 activates the first heater 28 and the second heater 29 (step S35). On the other hand, when the temperature in the field of view of the front window 6 is higher than the threshold temperature (step S38: No), the defogging control unit 54 activates only the first heater 28 (step S39).

[0096] As described above, in the fourth embodiment, the first condition (i.e., the condition for activating the first heater 28 and the second heater 29) includes the condition that the temperature within the field of view of the front window 6 is equal to or lower than the threshold temperature. Therefore, activation of the second heater 29 can be suppressed in a state where the temperature within the field of view of the front window 6 is relatively high. Therefore, the occurrence of thermal distortion in the front window 6 within the field of view of the front camera 10 can be more effectively suppressed.

[0097] In the fourth embodiment, when the vehicle speed is equal to or higher than the reference speed, the defogger control unit 54 determines whether the temperature in the field of view is equal to or lower than a prescribed threshold temperature. On the other hand, in another embodiment, when the vehicle speed is equal to or higher than the reference speed, the defogger control unit 54 may activate the first heater 28 and the second heater 29. In addition, when the vehicle speed is lower than the reference speed, the defogger control unit 54 may determine whether the temperature in the field of view is equal to or lower than a prescribed threshold temperature.

[0098] In the above-mentioned first to fourth embodiments, the defog system X is configured to defog the front window 6. In another embodiment, the defog system X may be configured to defog the rear window 7 or the side window 9. In other words, in the above-mentioned first to fourth embodiments, the front camera 10 is used as an example of an imaging device. In another embodiment, a rear camera (not shown) or a side camera (not shown) may be used as an example of an imaging device.

[0099] The specific embodiments of the present invention have been described above, but the present invention is not limited to the foregoing embodiments, and various modifications and changes can be made within the scope of the present invention.

Claims

1. A defogging system installed in a vehicle including an imaging device, the imaging device being configured to photograph an exterior space of the vehicle from an interior space of the vehicle through a window, the defogging system comprising: a vehicle speed sensor configured to detect a vehicle speed; a first heater disposed outside the field of view of the imaging device and configured to heat the window; a second heater disposed within the field of view of the imaging device and disposed in contact with the window and configured to heat the window; as well as a controller configured to control the first heater and the second heater, Wherein, the controller is configured as: determining whether the vehicle is stopped based on the detection result of the vehicle speed sensor, The first heater and the second heater are activated when a first condition is satisfied, the first condition including a condition that the vehicle is stopped, and Only the first heater is activated when a second condition is satisfied, the second condition including a condition that the vehicle is traveling.

2. The demisting system according to claim 1, wherein: The first condition includes a condition that the vehicle is stopped or a condition that the vehicle is traveling at a speed equal to or higher than a prescribed reference speed, and The second condition includes a condition that the vehicle travels at a speed lower than the reference speed.

3. The demisting system according to claim 1 or 2, further comprising a heater temperature sensor, wherein the heater temperature sensor is configured to detect a temperature of the second heater, in, The first condition includes a condition that the temperature of the second heater is equal to or lower than a prescribed threshold temperature.

4. The defogging system according to claim 1 or 2, further comprising a window temperature sensor, the window temperature sensor being configured to detect a temperature of a field-of-view portion of the window, the field-of-view portion being a portion within the field of view of the imaging device, and The first condition includes a condition that the temperature of the portion of the window within the field of view is equal to or lower than a specified threshold temperature.

5. The defog system according to claim 1 or 2, further comprising an external temperature sensor configured to detect a temperature of an external space of the vehicle, in, The first condition and the second condition each include a condition that the temperature of the external space of the vehicle is lower than a prescribed reference temperature.

6. The demisting system according to claim 1 or 2, wherein: The first heater is in contact with the window.

7. The demisting system according to claim 1 or 2, wherein: The first heater faces the window at a certain interval.

8. The demisting system according to claim 1 or 2, wherein: When the vehicle is traveling, the controller performs traveling control of the vehicle based on the image captured by the imaging device.

Images