WO2018230358A1 - Electromagnetic wave utilization system - Google Patents

Abstract

This electromagnetic wave utilization system is provided with an electromagnetic wave device (100, 201) and a heater (11, 21). The electromagnetic wave device sends and/or receives electromagnetic waves. The heater heats a passage section (1, 203) through which the electromagnetic waves utilized by the electromagnetic wave device are passed. The heater includes a heating element (111) that produces heat when a current flows, and a holding section (112) for holding the heating element. The heating element and the holding section are transparent to the electromagnetic waves utilized by the electromagnetic wave device. This makes it possible to heat the passage section without obstructing the passage of the electromagnetic waves.

Description

Electromagnetic wave utilization system Cross-reference of related applications

This application includes Japanese Patent Application No. 2017-116049 filed on June 13, 2017, Japanese Patent Application No. 2018- filed on Feb. 14, 2018, the disclosure of which is incorporated herein by reference. No. 023883 and Japanese Patent Application No. 2018-0773015 filed on Apr. 5, 2018.

This disclosure relates to an electromagnetic wave utilization system that utilizes electromagnetic waves.

Conventionally, Patent Document 1 describes an in-vehicle camera that captures a rear view of a vehicle. In this prior art, the vehicle-mounted camera is installed on the ceiling in the vehicle compartment in the vicinity of the rear window, and images the outside through the rear window.

In this conventional technology, the in-vehicle camera is installed so that the heater wire of the rear window defogger does not enter the imaging range. The defogger is a device that clears the fog of the rear window by heating the rear window with a heater wire.

JP-A-2-300715

According to this conventional technology, since the in-vehicle camera is installed so that the heater wire of the rear window defogger does not fall within the imaging range, the field of view of the in-vehicle camera is not hindered by the heater wire of the defogger.

However, in this conventional technique, since there is no defogger heater wire in the imaging range, the clouding in the imaging range cannot be cleared well. Therefore, the visibility of the field of view of the in-vehicle camera may not be ensured satisfactorily under conditions where the rear window is cloudy.

This fear similarly occurs not only in an in-vehicle camera that captures visible light but also in various electromagnetic wave utilization systems that use electromagnetic waves, such as a vehicle laser device that transmits and receives laser light.

This indication aims at providing the electromagnetic wave utilization system which can perform the heating of the passage part through which electromagnetic waves pass, without preventing the passage of electromagnetic waves in view of the above-mentioned point.

The electromagnetic wave utilization system according to one aspect of the present disclosure includes an electromagnetic wave device and a heater. The electromagnetic wave device performs at least one of transmission and reception of electromagnetic waves. The heater heats a passing portion through which electromagnetic waves used by the electromagnetic wave device pass. The heater includes a heating element that generates heat when an electric current flows, and a holding unit that holds the heating element. The heating element and the holding unit are transparent to the electromagnetic wave used by the electromagnetic wave device.

This allows the passage part to be heated without obstructing the passage of electromagnetic waves.

It is sectional drawing of the vehicle carrying the vehicle imaging device in 1st Embodiment. It is a partial expanded sectional view which shows the imaging device for vehicles of FIG. It is a top view of a heater. It is a flowchart which shows the control processing which the control apparatus of the imaging device for vehicles in 1st Embodiment performs. It is sectional drawing which shows the laser apparatus in 2nd Embodiment. FIG. 6 is a view taken in the direction of arrow VI in FIG. 5.

Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, the vehicle photographing device of the present embodiment will be described with reference to the drawings. In the figure, the up and down arrows indicate the up and down and front and rear directions of the vehicle. The vehicle photographing device is an electromagnetic wave utilization system that utilizes visible light, which is a type of electromagnetic wave.

As shown in FIG. 1, the camera unit 10 is attached to a surface on the vehicle interior side of the windshield 1 of the vehicle. The camera unit 10 is attached to the upper part of the windshield 1 of the vehicle and the substantially central part in the left-right direction. The camera unit 10 is located in the vicinity of a rearview mirror (not shown).

As shown in FIG. 2, the camera unit 10 includes a camera 100 and a housing 101. The camera 100 takes an image of the outside in front of the vehicle through the vehicle window (the windshield 1 in this example). The camera 100 is an electromagnetic wave device that captures visible light, which is a type of electromagnetic wave. The windshield 1 is a passage portion through which visible light taken by the camera 100 passes.

The image data captured by the camera 100 is input to the image processing apparatus 20. The image processing device 20 processes the image data of the camera 100 and detects an object in front of the vehicle. The detection result of the image processing device 20 is output to the collision safety control device 26. The collision safety control device 26 controls a vehicle brake and the like based on the detection result of the image processing device 20 to prevent a vehicle collision.

The camera 100 is housed in a housing 101. The housing 101 is a member that constitutes the outer shell of the camera unit 10. The housing 101 may be in close contact with the windshield 1, or a predetermined gap may be provided between the housing 101 and the windshield 1.

The front glass 1 is provided with a heater 11. The heater 11 heats the windshield 1 by generating heat, and clears the fog on the surface of the windshield 1 on the vehicle interior side, or melts snow and frost on the surface of the windshield 1 on the vehicle exterior side. Fulfill.

The heater 11 is a transparent thin film member. The heater 11 is affixed to the surface of the windshield 1 on the vehicle interior side. The heater 11 may be embedded in the windshield 1.

As shown in FIG. 3, the heater 11 includes a carbon nanotube 111 and a binder 112. The carbon nanotube 111 is a heating element that generates heat when an electric current flows. In FIG. 3, for convenience of illustration, the carbon nanotube 111 is indicated by a broken straight line.

The carbon nanotube 111 (also called CNT) is a carbon crystal having a hollow cylindrical structure. The diameter of the carbon nanotube 111 is 0.7 to 70 nm, which is about one tenth of the hair. The carbon nanotube 111 is a tube-shaped substance having a length of several tens of μm or less.

The binder 112 is a holding unit that holds the carbon nanotubes 111. The material of the binder 112 is a transparent resin.

For example, the heater 11 is a thin film in which carbon nanotubes 111 are dispersed in a binder 112. The heater 11 may have a plurality of line-shaped heating lines using a wire formed using the carbon nanotubes 111. The diameter of the wire formed using the carbon nanotube 111 is about several μm.

The carbon nanotube 111 is a member that is so thin that it cannot be identified with the naked eye. The wire formed using the carbon nanotube 111 is also a thin member that cannot be identified with the naked eye. Therefore, the heater 11 looks transparent to the naked eye. The carbon nanotube 111 can absorb light and prevent light scattering.

The heater 11 has a pair of electrodes 113a and 113b. The electrodes 113a and 113b are connected to the carbon nanotube 111.

When a DC voltage is applied from the vehicle battery 12 to the electrodes 113a and 113b, a current flows through the carbon nanotube 111 and the carbon nanotube 111 generates heat. The electrodes 113 a and 113 b are formed in an elongated shape along the edge of the heater 11.

The energization unit 13 switches between applying and interrupting a DC voltage from the battery 12 to the electrodes 113a and 113b. The energization unit 13 has a relay or a switch. The operation of the energization unit 13 is controlled by the heater control device 14.

The heater 11 is disposed so as to overlap the entire range of the field of view v1 of the camera 100. In FIG. 3, the field of view v1 of the camera 100 is indicated by a two-dot chain line for easy understanding. The heater 11 is arranged up to a range wider than the field of view v1 of the camera 100.

The electrodes 113a and 113b of the heater 11 are disposed outside the field of view v1 of the camera 100. This prevents the field of view v1 of the camera 100 from being obstructed by the heater 11.

The heater control device 14 is composed of a well-known microcomputer including a CPU, ROM, RAM, etc. and its peripheral circuits, and performs various calculations and processing based on a control program stored in the ROM, and is connected to the output side. Control the operation of various devices.

A window surface humidity sensor 15 is connected to the input side of the heater control device 14. The window surface humidity sensor 15 includes a window vicinity humidity sensor, a window vicinity air temperature sensor, and a window surface temperature sensor.

The near-window humidity sensor detects the relative humidity of the air in the passenger compartment near the windshield 1 in the passenger compartment. Hereinafter, the relative humidity is referred to as near window relative humidity. The near window air temperature sensor detects the temperature of the air in the passenger compartment near the windshield 1. The window surface temperature sensor detects the surface temperature of the windshield 1.

The energization unit 13, the heater control device 14, and the window surface humidity sensor 15 are heater control units that control the operation of the heater 11.

The heater control device 14 executes the control process shown in the flowchart of FIG. The flowchart of FIG. 4 shows a subroutine of a control program executed by the heater control device 14.

First, in step S100, based on the detection value of the window surface humidity sensor 15, the relative humidity RHW of the vehicle interior side surface of the windshield 1 is calculated. The relative humidity RHW is hereinafter referred to as window surface relative humidity RHW.

The window surface relative humidity RHW is an index representing the possibility that the windshield 1 is clouded. Specifically, the larger the value of the window surface relative humidity RHW, the higher the possibility that the windshield 1 will be fogged.

In step S110, it is determined whether or not the window surface relative humidity RHW is equal to or higher than the threshold value α. When it is determined in step S110 that the window surface relative humidity RHW is equal to or higher than the threshold value α, the process proceeds to step S120, and the heater 11 is caused to generate heat. Specifically, the heater control device 14 applies a DC voltage from the vehicle battery 12 to the electrodes 113 a and 113 b of the heater 11.

Thereby, when the possibility that the windshield 1 is fogged is high, the windshield 1 is heated by the heater 11 to prevent the windshield 1 from being fogged, or when the windshield 1 is fogged, the windshield 1 is heated by the heater 11. Then, the cloudiness of the windshield 1 can be cleared.

On the other hand, if it is determined in step S110 that the window surface relative humidity RHW is not equal to or higher than the threshold value α, the process proceeds to step S130, and the heat generation of the heater 11 is stopped. Specifically, the heater control device 14 cuts off the application of a DC voltage to the electrodes 113a and 113b of the heater 11.

In this embodiment, the heater 11 that heats the windshield 1 is disposed in the windshield 1 at a position corresponding to the field of view v1 of the camera 100. The heater 11 includes a carbon nanotube 111 and a binder 112. The carbon nanotube 111 is a member that cannot be identified with the naked eye. The binder 112 is made of a transparent material.

According to this, since the heater 11 is in the field of view v1 of the camera 100, the clouding of the field of view v1 can be cleared well. Furthermore, since the carbon nanotube 111 of the heater 11 is a member that cannot be identified with the naked eye, and the binder 112 of the heater 11 is formed of a transparent material, the heater 11 can be made transparent. Therefore, the heater 11 can be prevented from obstructing the field of view v1 of the camera 100.

In the present embodiment, the heating element of the heater 11 is formed of the carbon nanotubes 111. According to this, since the carbon nanotube 111 can absorb light and prevent light scattering, the transparency of the heater 11 can be improved.

In the present embodiment, the energization unit 13, the heater control device 14, and the window surface humidity sensor 15 determine the possibility that the windshield 1 will be fogged. Shed. Thereby, the heater 11 can be operated efficiently.

The energization unit 13, the heater control device 14, and the window surface humidity sensor 15 determine whether or not the windshield 1 is clouded. If it is determined that the windshield 1 is clouded, an electric current may be passed through the heater 11. . According to this, the heater 11 can be operated efficiently.

In the present embodiment, the electrodes 113a and 113b of the heater 11 are members that can be identified with the naked eye, and are disposed outside the field of view v1. According to this, it is possible to avoid that the electrodes 113a and 113b that can be identified with the naked eye interfere with the field of view v1 of the camera 100.

(Second Embodiment)
In the above embodiment, the vehicular photographing apparatus including the heater 11 has been described. In the present embodiment, the vehicular laser apparatus 24 including the heater 21 will be described with reference to FIGS. 5 and 6.

The vehicle laser device 24 is a device that measures the distance, direction, attributes, and the like of an object from the time it takes to irradiate a laser beam in a pulse shape and is reflected by an object and returns. Used as a sensor.

The vehicle laser device 24 includes a laser handset 201, a housing 202, and a cover 203. The laser transmitter / receiver 201 is a device that irradiates a laser beam and detects the object and measures the distance to the object by receiving the laser beam reflected back from the object.

For example, the vehicle laser device 24 is attached to a bumper (not shown) of the vehicle, irradiates laser light toward the front of the vehicle, and receives laser light returned from the front of the vehicle. The laser light emitted by the vehicle laser device 24 is, for example, laser light having a near infrared wavelength.

The operation of the laser handset 201 is controlled by the automatic operation control device 22. Detection results and measurement results by the laser handset 201 are input to the automatic operation control device 22. The automatic driving control device 22 performs automatic driving of the vehicle based on the detection result and the measurement result by the laser handset 201.

The laser transmitter / receiver 201 is accommodated in a space sealed by a housing 202 and a cover 203. The housing 202 and the cover 203 are members that house the laser transmitter / receiver 201 and protect the laser transmitter / receiver 201. The housing 202 is disposed in a region where the laser light transmitted and received by the laser handset 201 does not pass. The cover 203 is disposed in an area through which the laser beam transmitted and received by the laser transmitter / receiver 201 passes. The cover 203 is made of resin.

The heater 21 is a transparent thin film-like member similar to the heater 11 of the first embodiment, and has carbon nanotubes and a binder. The carbon nanotubes and the binder of the heater 21 are transparent to the laser light transmitted and received by the laser transmitter / receiver 201.

The transparency of the heater 21 with respect to the laser beam transmitted / received by the laser transmitter / receiver 201 is 80% or more. Therefore, it can be avoided that the heater 21 prevents the laser beam from passing through the cover 203. The transparency of the heater 21 with respect to the laser beam transmitted and received by the laser transmitter / receiver 201 is preferably about 95%.

The heater 21 is bonded to the inner surface of the cover 203 by adhesion. The heater 21 may be attached to the outer surface of the cover 203. The heater 21 may be insert-molded in the cover 203.

The heater 21 has flexibility to follow the curved shape of the cover 203 surface. The heater 21 is provided in part or all of the region of the cover 203 through which the laser beam transmitted and received by the laser transmitter / receiver 201 passes.

The cover 203 and the heater 21 are transparent to the laser light transmitted and received by the laser transmitter / receiver 201. In other words, the cover 203 and the heater 21 transmit the laser light transmitted and received by the laser transmitter / receiver 201.

When a DC voltage is applied to an electrode (not shown) of the heater 21 from a battery (not shown) of the vehicle, a current flows through the carbon nanotube (not shown) of the heater 21 and the carbon nanotube generates heat. The electrode of the heater 21 is formed in an elongated shape along the edge of the heater 21.

Since the housing 202 and the cover 203 form a sealed space, fogging may occur inside the cover 203 due to a temperature difference between the inside and outside of the sealed space. In winter, snow may adhere to the outside of the cover 203.

In the present embodiment, since the heater 21 heats the cover 203, the fog inside the cover 203 can be cleared well or the snow outside the cover 203 can be melted well.

Moreover, since the heater 21 is transparent to the laser light used by the laser handset 201, it is possible to avoid the laser light passing through the cover 203 from being obstructed by the heater 21.

Since the cover 203 is made of resin, the amount of laser light absorbed by the cover 203 can be kept lower than when the cover 203 is made of glass.

(Other embodiments)
The above embodiments can be combined as appropriate. The above embodiment can be variously modified as follows, for example.

(1) In the first embodiment, the heater 11 is disposed up to a range that is slightly wider than the field of view v1 of the camera 100 in the windshield 1, but the heater 11 is disposed on the entire windshield 1. May be. Thereby, it can prevent favorably that the windshield 1 fogs. Since the heater 11 is transparent, it can suppress that the heater 11 obstruct | occludes a passenger | crew's visual field.

(2) In the first embodiment, the camera unit 10 and the heater 11 are disposed on the windshield 1, but the camera unit 10 and the heater 11 are disposed on a window other than the windshield 1, such as a rear glass. May be.

(3) In the said 1st Embodiment, although the heater 11 is arrange | positioned at the windshield 1, the heater 11 protects lamps (namely, apparatus which irradiates visible light), such as a headlight cover of a vehicle. May be arranged. The material of the cover of the lighting device is glass or resin.

(4) In the first embodiment, the carbon nanotube 111 is used as the heating element of the heater 11. However, a member such as metal particles, carbon particles, and metal oxide particles that cannot be identified with the naked eye is used as the heating element of the heater 11. It may be used. In other words, various members that are transparent to the light captured by the camera 100 may be used.

(5) In the first embodiment, the image data of the camera 100 is used to prevent the collision of the vehicle. However, the present invention is not limited to this, and various applications such as prevention of lane departure and distance measurement between vehicles are possible. The image data of the camera 100 may be used.

(6) The camera 100 of the first embodiment is a camera that captures visible light, but may be a camera that captures infrared light or ultraviolet light.

(7) The vehicle laser device 24 according to the second embodiment transmits and receives laser light toward the front of the vehicle, and transmits and receives laser light while rotating the laser handset 201 in a horizontal plane. Also good. In that case, the heater 21 may be rotated together with the laser transmitter / receiver 201 or the heater 21 may be provided so as to surround the laser transmitter / receiver 201 by 360 degrees.

(8) Although the heater 21 is used in the vehicle laser device 24 in the second embodiment, the heater 21 may be used in a vehicle radio wave device. A vehicle radio wave device is a device that measures the distance, direction, attributes, and the like of an object from the time it takes to radiate radio waves and return after being reflected by an object, and is used, for example, as a vehicle automatic driving sensor.

In this case, the heater 21 removes fogging of the cover of the vehicle radio device, so that moisture due to fogging can be prevented from affecting the radio wave.

(9) In the second embodiment, the heating element of the heater 21 is a carbon nanotube, but the heating element of the heater 21 may be indium tin oxide, silver mesh, or the like. That is, various members that are transparent to the laser light used by the laser handset 201 may be used.

(10) In the above embodiment, as a specific example of the electromagnetic wave utilization system, a vehicle photographing device and a vehicle laser device are shown. However, the electromagnetic wave utilization system is a stationary photographing device, a stationary laser device, or the like. May be.

Claims (9)

An electromagnetic wave device (100, 201) that performs at least one of electromagnetic wave transmission and reception;
A heater (11, 21) for heating the passage (1, 203) through which the electromagnetic wave used by the electromagnetic wave device passes,
The heater includes a heating element (111) that generates heat when a current flows, and a holding portion (112) that holds the heating element.
The heating element and the holding unit are electromagnetic wave utilization systems that are transparent to the electromagnetic waves utilized by the electromagnetic wave device. The electromagnetic wave utilization system according to claim 1, wherein the heating element is formed of carbon nanotubes. The electromagnetic wave utilization system according to claim 2, wherein the passage portion is made of resin. The electromagnetic wave device (201) is a device that irradiates a laser beam through the passing portion and receives the laser beam returned by being reflected by an object,
The electromagnetic wave is the laser beam used by the electromagnetic wave device,
The electromagnetic wave utilization system according to any one of claims 1 to 3, wherein the passage portion is a cover (203) for protecting the electromagnetic wave device. The electromagnetic wave device is a camera (100) that takes an image of the outside of the vehicle through the passage portion,
The passage is a window (1) of the vehicle;
The electromagnetic wave utilization system according to any one of claims 1 to 3, wherein the heater is disposed at a position corresponding to a field of view (v1) of the camera in the window. The electromagnetic wave utilization system according to claim 5, further comprising: a heater control unit (13, 14, 15) that determines a possibility that the window is fogged and causes a current to flow to the heater when the possibility that the window is fogged increases. 6. The electromagnetic wave utilization system according to claim 5, further comprising: a heater control unit (13, 14, 15) that determines whether or not the window is clouded and flows a current to the heater when it is determined that the window is clouded. . The heater has a pair of electrodes (113a, 113b) connected to the heating element,
The electromagnetic wave utilization system according to any one of claims 5 to 7, wherein the electrode is disposed outside the field of view (v1). The electromagnetic wave device is a device that emits visible light through the passage part,
The electromagnetic wave is the visible light irradiated by the electromagnetic wave device,
The electromagnetic wave utilization system according to claim 1, wherein the passage portion is a cover that protects the electromagnetic wave device.

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