Laser irradiation device

Abstract

To enhance irradiation precision of laser light through a window.SOLUTION: A laser irradiation device (1) comprises a light source which emits laser light, an irradiator (12) which includes an enclosure (21) through which the laser light from the light source passes and a window (23) provided at a laser light exit of the enclosure (21), and a dirt preventive device which prevents the window (23) from getting dirty. The dirt preventive device is, for example, a cover device (14) which covers the window (23).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a laser irradiation device that irradiates a laser. [Background technology]

[0002] A known laser irradiation device is disclosed in Patent Document 1. This laser irradiation device includes a light source, a laser irradiation unit, and an optical system that guides a laser from the light source to the laser irradiation unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6654028 Summary of the Invention [Problem to be solved by the invention]

[0004] When irradiating a laser from a laser irradiation unit, a window that allows the laser to pass through must be provided at the laser irradiation port in order to maintain the cleanliness and dryness of the laser irradiation device. However, if the window is dirty, the laser will be refracted as it passes through the window, which may reduce the accuracy of the laser irradiation.

[0005] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a laser irradiation device that can improve the accuracy of laser irradiation through a window. [Means for solving the problem]

[0006] In order to solve the above problem, a laser irradiation device according to one aspect of the present disclosure includes a light source that generates a laser, an irradiator that includes a housing through which the laser from the light source passes and a window provided at the laser exit of the housing, and a dirt prevention device that prevents the window from becoming dirty. [Effects of the Invention]

[0007] According to the laser irradiation device of the present disclosure, it is possible to irradiate a laser beam through a clean window with high precision. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a laser irradiation device according to an embodiment of the present disclosure and a high-power laser system including the same, and is a side view showing the high-power laser system when the cover device is in an open state. [Figure 2] FIG. 2 is a side view showing the high-power laser system when the cover device is in a closed state. [Figure 3] FIG. 2 is a side view showing the details of the laser irradiation device. [Figure 4] FIG. 2 is a perspective view showing the details of the laser irradiation device. [Figure 5] FIG. 2 is a perspective view showing the laser irradiation device when the cover device is in an open state. [Figure 6] FIG. 2 is a perspective view showing the laser irradiation device when the cover device is in a closed state. [Figure 7] FIG. 2 is a side view showing the configuration of a blowing device and a cleaning device. [Figure 8] FIG. 10 is a front view showing how air is blown from the blowing device. [Figure 9] FIG. 10 is a front view showing how washer fluid is sprayed from the cleaning device. [Figure 10] FIG. 2 is a functional block diagram showing a control system of the high-power laser system. [Figure 11] 10 is a flowchart illustrating an example of a control operation executed by a controller of the high-power laser system. [Figure 12A] FIG. 1 is a diagram for explaining how a target is tracked using a tracking camera. [Figure 12B] FIG. 10 is a diagram for explaining how tracking converges. [Figure 13] FIG. 10 is a side view of a laser irradiation device according to a modified example of the embodiment. [Figure 14A] FIG. 10 is a side view of a laser irradiation device according to another modified example of the embodiment. [Figure 14B] FIG. 10 is a side view showing a state in which the irradiation window is covered with a lower cover in the other modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Overall system configuration] 1 and 2 are side views showing a schematic configuration of a laser irradiation device 1 according to an embodiment of the present disclosure and a high-power laser system including the same. The high-power laser system shown in these figures is a laser system for irradiating a target with a high-power laser from the laser irradiation device 1. The high-power laser irradiation by this system may be performed, for example, for the purpose of transmitting power to an air vehicle or flying object that is powered by electricity and autonomously steers itself. Alternatively, the high-power laser may be irradiated for the purpose of repelling or immobilizing a flying or flying harmful object. In this case, the harmful object may be, for example, a flying or flying harmful bird or animal.

[0010] The laser irradiation device 1 is mounted on a vehicle 101 as a moving body. The vehicle 101 includes an engine 102 as a power source, wheels 103 rotated and driven by the engine 102, a cabin 104 with a built-in driver's seat, a frame 105 connected to the cabin 104, and a container 106 supported by the frame 105. The above-mentioned laser irradiation device 1 is mounted on the container 106. Furthermore, the container 106 is equipped with a radar detector 110 that detects targets using radar. In other words, the high-power laser system of this embodiment is a mobile laser system equipped with the laser irradiation device 1 and the radar detector 110 mounted on the vehicle 101. Note that in this embodiment, for convenience of the following explanation, the up-down direction, left-right direction, front-rear direction, and horizontal direction of the vehicle 101 are defined as the up-down direction, left-right direction, front-rear direction, and horizontal direction of a driver sitting in the driver's seat of the vehicle 101.

[0011] The laser irradiation device 1 includes a laser oscillator 11, an irradiation optical device 12, a support mechanism 13, and a cover device 14 shown in Fig. 2. The laser oscillator 11 is a light source that generates the laser Lb shown in Fig. 1. The irradiation optical device 12 is an irradiator that irradiates the laser Lb oscillated from the laser oscillator 11 while guiding the laser Lb in a desired direction. The support mechanism 13 is a mechanism that supports the irradiation optical device 12 so that it can rotate and tilt. The cover device 14 is a device that includes an openable cover for covering the irradiation optical device 12.

[0012] The cover device 14 in this embodiment and the blow device 15 and cleaning device 16 described below all correspond to the "fouling prevention device" in this disclosure. Preventing contamination in this disclosure includes not only preventing adhesion of various foreign matter to the irradiation window 23 described below, but also monitoring and removing foreign matter adhering to the irradiation window 23.

[0013] The laser oscillator 11 is disposed inside a container 106, and the irradiation optical device 12 and the support mechanism 13 are disposed on the container 106. The cover device 14 has a cover that can be retracted into and out of the container 106. That is, the cover device 14 is switchable between an open state shown in FIG. 1 in which the irradiation optical device 12 and the support mechanism 13 are exposed on the container 106, and a closed state shown in FIG. 2 in which the irradiation optical device 12 and the support mechanism 13 are covered. The interior of the container 106 may be used not only as a storage room that houses the laser oscillator 11, but also as an operator's room where an operator who operates the laser irradiation device 1 is stationed.

[0014] The laser Lb generated by the laser oscillator 11 can be of any type as long as it is a high-power laser, but an iodine laser or a fiber laser is suitable. An iodine laser is a type of gas laser generated by a chemical reaction between excited oxygen and iodine. When using an iodine laser, the laser oscillator 11 can include, for example, an excited oxygen generator that generates excited oxygen, an iodine supplying device that supplies iodine that reacts with the excited oxygen generated by the generator, and a laser resonator that generates laser oscillation through a chemical reaction between the excited oxygen and iodine. A fiber laser is a type of electrically driven laser that oscillates a laser using an optical fiber doped with a laser-active element and has advantages such as high-efficiency oscillation and high beam quality. When using a fiber laser, the laser oscillator 11 can include, for example, a semiconductor laser as an excitation light source, a coupler that couples the light from the semiconductor laser to an optical fiber doped with an active element that serves as a medium, and a laser resonator that extracts laser light from the optical fiber in a state excited by the semiconductor laser.

[0015] 3 and 4 are side and perspective views showing the details of the illumination optical device 12 and the support mechanism 13. The term "side" here refers to the side of the illumination optical device 12, and refers to a surface perpendicular to the Y-axis, which is the extension direction of a tilting shaft 33a (described later) for tilting the illumination optical device 12 in the vertical direction of the vehicle 101. In this embodiment, the Z-axis, which is the extension direction of a pivoting shaft 31a (described later) for pivoting the illumination optical device 12, coincides with the vertical direction of the vehicle 101. Therefore, the direction in which the side of the illumination optical device 12 faces coincides with the horizontal direction of the vehicle 101. However, this is not necessarily the case depending on the installation position and mounting direction of the illumination optical device 12 relative to the vehicle 101. As shown in these figures, the illumination optical device 12 includes a housing 21, an optical module 22, an illumination window 23, a tracking camera 24, and a photographing window 25. The housing 21 is a substantially rectangular cylindrical housing that houses the optical module 22 and the tracking camera 24. The optical module 22 is a group of optical components that condenses the laser beam Lb output from the laser oscillator 11 and directs it in a desired direction, and includes, for example, a condensing lens and a refractive lens. The irradiation window 23 is a transparent member made of a glass plate or the like that is transparent to the laser beam Lb output from the optical module 22, and is attached to the front end surface 21a of the housing 21, which is the exit of the laser beam Lb. The tracking camera 24 is an imaging device that captures an image of a target in order to track the target. The imaging window 25 is a transparent member made of a glass plate or the like that is attached to the front end surface 21a of the housing 21 in order to capture an image into the tracking camera 24. The irradiation window 23 corresponds to the "window" in this disclosure.

[0016] The irradiation optical system 12 irradiates a laser beam from the optical module 22 through the irradiation window 23 while being attitude-controlled so as to point at the target photographed by the tracking camera 24. This allows the laser beam to be irradiated onto the target.

[0017] The irradiation window 23 and the imaging window 25 are airtightly attached to the front end surface 21a of the housing 21. In other words, the inside of the housing 21 is sealed. Dry gas is sealed inside this sealed housing 21. The dry gas serves to suppress the generation of water vapor inside the housing 21. This prevents the water vapor from absorbing the laser Lb passing through the housing 21, and ultimately prevents the refractive index of the laser Lb from changing due to a temperature rise associated with the absorption of the laser.

[0018] The support mechanism 13 is a so-called two-axis gimbal mechanism. The illumination optical device 12 supported by this support mechanism 13 can rotate in the direction of arrow A1, which is rotation about the Z axis, and tilt in the direction of arrow A2, which is rotation about the Y axis perpendicular to the Z axis. As described above, the Z axis of the support mechanism 13 in this embodiment extends in the vertical direction of the vehicle 101. Furthermore, the Y axis of the support mechanism 13 in this embodiment extends in the horizontal direction of the vehicle 101.

[0019] Specifically, the support mechanism 13 includes a base 31, a revolving unit 32, a pair of support legs 33 that support the illumination optical device 12 from both side surfaces thereof, and a Z-axis motor 34 and a Y-axis motor 35 shown in FIG. 10 . The base 31 is a disk-shaped platform fixed to the upper surface of the container 106. The revolving unit 32 is a disk-shaped rotating body disposed on the base 31 and is pivotally supported on the base 31 via a pivot shaft 31a extending in the Z-axis direction. The pair of support legs 33 are members that protrude from the revolving unit 32 above the vehicle 101, in other words, protrude to one side in the Z-axis direction, and are disposed so as to sandwich the illumination optical device 12 from both side surfaces thereof. Each support leg 33 pivotally supports the illumination optical device 12 via a tilt shaft 33a extending in the Y-axis direction. The Z-axis motor 34 is an electric motor that rotates the revolving unit 32 around the Z-axis as indicated by arrow A1. The Y-axis motor 35 is an electric motor that rotates the irradiation optical system 12 around the Y-axis as indicated by an arrow A2.

[0020] As the rotating body 32 is rotated by the Z-axis motor 34, the irradiation optical device 12 rotates around the Z-axis together with the support leg 33. As the Y-axis motor 35 is rotated, the irradiation optical device 12 tilts around the Y-axis relative to the support leg 33. In the laser irradiation device 1 of this embodiment, the irradiation optical device 12 is supported by the support mechanism 13 in such a state that it can rotate and tilt, so that the front end surface 21a on which the irradiation window 23 and the imaging window 25 are located can be directed in all directions.

[0021] The irradiation optical device 12 and the laser oscillator 11 are connected via a light guide path 18, which is simply shown in Fig. 4. The light guide path 18 is a path for introducing the laser beam Lb oscillated from the laser oscillator 11 into an optical module 22 inside the irradiation optical device 12. When the laser beam Lb is to be irradiated onto a target, the laser beam Lb is introduced from the laser oscillator 11 into the optical module 22 through the light guide path 18. The laser beam Lb introduced into the optical module 22 is then guided to the outside through an irradiation window 23.

[0022] FIG. 5 is a perspective view showing the laser irradiation device 1 when the cover device 14 is in an open state, and FIG. 6 is a perspective view showing the laser irradiation device 1 when the cover device 14 is in a closed state. As shown in this figure, the cover device 14 has a two-piece structure and includes two element covers 41A and 41B that can rotate around a support shaft 42, and a cover motor 43 shown in FIG. 10 that rotates both element covers 41A and 41B. Each of the element covers 41A and 41B has a shape obtained by dividing a spherical shell into four parts and is attached to the container 106 so that it can rotate around the support shaft 42 within an angle range close to 90 degrees. In other words, the cover device 14 is a dome-shaped device that can cover and conceal the irradiation optical device 12 and support mechanism 13 on the container 106 with the spherical shell-shaped element covers 41A and 41B. The container 106 is formed with a recessed space C for accommodating the element covers 41A and 41B when the cover device 14 is open. The cover motor 43 is an electric motor linked to each of the element covers 41A, 41B via gears or the like, and is capable of rotating the element covers 41A, 41B simultaneously in opposite directions around the support shaft .

[0023] When the cover device 14 shown in FIG. 6 is closed, the cover motor 43 rotates each of the element covers 41A and 41B to a position where almost the entire element covers 41A and 41B protrude above the container 106. As a result, the element covers 41A and 41B are butted together above the container 106, and a state in which the element covers 41A and 41B are continuous across the semicircular dividing line B is obtained. This creates a dome-shaped closed cover device 14, which conceals the irradiation optical device 12 and the support mechanism 13 of the laser irradiation device 1 from the outside world. On the other hand, when the cover device 14 shown in FIG. 5 is opened, the cover motor 43 rotates each of the element covers 41A and 41B to a position where most of the element covers 41A and 41B are housed within the container 106. As a result, the spherical shell formed by the element covers 41A and 41B opens in the left-right direction of the vehicle 101, and the irradiation optical device 12 and the support mechanism 13 are exposed above the container 106. When the cover device 14 is open, the ends of the element covers 41A and 41B are not butted together inside the container 106, but are spaced apart from each other. This is to ensure space for the above-mentioned light guide 18 (FIG. 4) that introduces the laser Lb to the irradiation optical device 12, etc.

[0024] FIG. 7 is a side view showing the irradiation window 23 and its surrounding structure, FIG. 8 is a front view showing the positional relationship between the irradiation window 23 and the blowing device 15 (described later), and FIG. 9 is a front view showing the positional relationship between the irradiation window 23 and the cleaning device 16 (described later). The side face here refers to the side face of the irradiation optical device 12, as in FIG. 3 . The front face here refers to the face perpendicular to the laser irradiation axis of the irradiation optical device 12 and facing the optical module 22 across the irradiation window 23. As shown in this figure, the laser irradiation device 1 further includes a blowing device 15 that blows air W1 onto the irradiation window 23 and a cleaning device 16 that sprays washer fluid W2 onto the irradiation window 23. While the shape of the irradiation window 23 to which the blowing device 15 and the cleaning device 16 can be applied is not particularly limited, this embodiment illustrates a case where the irradiation window 23 is circular in front view. In the following description, the surface of the irradiation window 23 refers to the front face when the direction of irradiation of the laser Lb is forward of the irradiation optical device 12, i.e., the face that faces the outside air.

[0025] 7 and 8, the blowing device 15 includes a plurality of air nozzles 51, an air supply source 52, and an air pipe 53. The plurality of air nozzles 51 are nozzles that blow air W1 from the periphery of the irradiation window 23 toward the surface of the irradiation window 23, and are arranged at equal intervals in a circle along the outer periphery of the irradiation window 23 with the nozzle openings facing the irradiation window 23, which is circular in front view. The air pipe 53 is a pipe that connects each air nozzle 51 to the air supply source 52. The air supply source 52 is a device that includes components such as a compressor that pressurizes and delivers air W1 to each air nozzle 51 through the air pipe 53.

[0026] Each air nozzle 51 can be switched between an open state in which the pressurized air W1 is blown onto the irradiation window 23 and a closed state in which the blowing of the air W1 is stopped. The air nozzles 51 are arranged such that the nozzle opening directions are at different angles so that the air W1 can be blown toward the center of the irradiation window 23, which is circular in front view.

[0027] As shown in FIGS. 7 and 9 , the cleaning device 16 includes a plurality of liquid nozzles 61, a liquid supply source 62, a liquid pipe 63, and a liquid receptacle 64. The liquid nozzles 61 are nozzles that spray washer fluid W2 from above the irradiation window 23 toward the surface of the irradiation window 23, and are arranged in an arc-shaped array at equal intervals along the upper edge of the irradiation window 23. The liquid pipe 63 is a pipe that connects each liquid nozzle 61 to the liquid supply source 62. The liquid supply source 62 is a device that includes components such as a pump that pressure-feeds the washer fluid W2 to each liquid nozzle 61 through the liquid pipe 63. Any type of washer fluid W2 may be used as long as it is capable of washing away dirt adhering to the irradiation window 23. For example, an aqueous solution containing a cleaning component such as a surfactant or a volatile component such as alcohol can be suitably used.

[0028] Each fluid nozzle 61 can be switched between an open state in which it sprays pressure-fed washer fluid W2 onto the irradiation window 23 and a closed state in which it stops spraying the washer fluid W2. When considering a state in which the laser irradiation direction of the irradiation optical device 12 shown in FIG. 1 and other figures is aligned with the front of the vehicle 101, each fluid nozzle 61 in this embodiment sprays the washer fluid W2 in a direction that has at least a downward component of the vehicle 101 and a directional component facing the front of the irradiation window 23. The washer fluid W2 sprayed from each fluid nozzle 61 flows from top to bottom on the surface of the irradiation window 23 and is then collected in a liquid receptacle 64. As shown in FIG. 9, a drain hose 64a is attached to the liquid receptacle 64 to drain accumulated liquid.

[0029] The above-described spray direction of air W1 from the air nozzle 51 and the spray direction of washer fluid W2 from the liquid nozzle 61 are merely examples. In particular, the liquid nozzle 61 is described as an example of a positional relationship that is convenient for spraying washer fluid W2 onto the entire surface of the irradiation window 23 and guiding the washer fluid W2 to the liquid receiver 64 using gravity, assuming that the reference position most frequently set during operation of the irradiation optical device 12 is the state shown in FIG. 1 . For example, if the laser irradiation device 1 is mounted with the Z axis aligned with the left-right direction of the vehicle 101, the spray direction of the washer fluid W2 from the liquid nozzle 61 is determined appropriately based on its relationship with the direction of gravity and the reference position setting of the irradiation optical device 12.

[0030] 10 is a functional block diagram showing a control system of a high-power laser system including the above-described laser irradiation device 1. As shown in this figure, the high-power laser system includes a controller 70 consisting of a microcomputer or the like. The controller 70 is electrically connected to each functional element of the laser irradiation device 1 and the radar detector 110.

[0031] The controller 70 acquires position information of the target from the radar detector 110 and controls the laser irradiation device 1 based on the acquired position information, etc. For example, the controller 70 drives the cover motor 43 to open and close the cover device 14, and drives the Z-axis motor 34 and the Y-axis motor 35 to control the attitude of the irradiation optical device 12. The controller 70 also drives the air nozzle 51 or the liquid nozzle 61 to spray air W1 or washer fluid W2 onto the irradiation window 23. Furthermore, the controller 70 causes the tracking camera 24 to photograph the target and causes the laser oscillator 11 to oscillate the laser Lb.

[0032] The laser irradiation device 1 includes a dirt sensor 17 that detects dirt on the irradiation window 23. The dirt sensor 17 is, for example, a sensor that optically detects dirt adhering to the irradiation window 23. The detection result by the dirt sensor 17 is input to the controller 70.

[0033] [Example of operation] 11 is a flowchart showing an example of a control operation executed by the controller 70. When the control shown in this figure starts, the controller 70 determines whether the radar detector 110 is in operation or not (step S1). In this embodiment, the cover device 14 of the laser irradiation device 1 is always in a closed state. That is, when this control starts, the laser irradiation device 1 is in a second mode, which will be described later.

[0034] The radar detector 110 is activated, for example, by an operator who recognizes the need for laser irradiation. That is, the operator inputs an activation command for the radar detector 110 into the controller 70, and upon receiving the activation command, the controller 70 activates the radar detector 110. When the radar detector 110 is in operation, that is, when the determination in step S1 is YES, the controller 70 determines whether or not a target has been detected by the radar detector 110 (step S2).

[0035] If the determination in step S2 is YES and detection of a target is confirmed, the controller 70 executes a control mode (hereinafter referred to as the first mode) in which air W1 is blown onto the irradiation window 23 with the cover device 14 open. That is, the controller 70 opens the air nozzle 51 to start air blowing, blowing air W1 onto the surface of the irradiation window 23 (step S3), and drives the cover motor 43 in the opening direction to open the cover device 14 (step S4). This first mode exposes the irradiation optical device 12 above the container 106, and protects the surface of the irradiation window 23 with the blown air W1.

[0036] Next, the controller 70 photographs and tracks the target using the tracking camera 24 (step S5). That is, the controller 70 controls the attitude of the illumination optical device 12 using the Z-axis and Y-axis motors 34, 35 of the support mechanism 13 so that the target detected by the radar detector 110 comes into the field of view of the tracking camera 24, and causes the tracking camera 24 to continuously photograph the target.

[0037] Next, the controller 70 determines whether the tracking has converged (step S6). FIGS. 12A and 12B are diagrams for explaining target tracking, showing images captured by the tracking camera 24. In FIG. 12A, point X1 indicates the tracking point, and point X2 indicates the laser aim. The tracking point X1 is a reference point included in the image of the target, and the laser aim X2 is the arrival point of the laser Lb emitted from the irradiation optical device 12. As shown in FIG. 12B, the controller 70 controls the attitude of the irradiation optical device 12 so that the tracking point X1 coincides with the laser aim X2. Then, when a stable state is achieved in which the tracking point X1 approximately coincides with the laser aim X2, the controller 70 determines that the tracking has converged.

[0038] If the determination in step S6 is YES and the tracking convergence is confirmed, the controller 70 irradiates the target with the laser beam Lb (step S7). That is, the controller 70 controls the laser beam 11 so that the laser beam Lb is emitted from the laser beam 11 to the irradiation optical unit 12. As a result, the laser beam Lb is introduced into the optical module 22, and the laser beam Lb is irradiated from the optical module 22 through the irradiation window 23.

[0039] Next, the controller 70 determines whether or not the target has been dealt with (step S8). The specific determination here varies depending on the purpose of the laser irradiation. For example, when performing laser irradiation for the purpose of wirelessly powering an autonomously flying or flying target, if the target is moving, it is necessary to continuously track the target for a certain period of time or more and irradiate the target with the laser Lb. Therefore, whether or not the deal has been dealt with, i.e., whether or not to continue or interrupt the power supply, can be determined, for example, by whether or not the time during which the target and the laser sight X2 continue to substantially coincide with each other exceeds a predetermined certain period of time. Alternatively, the target may be equipped in advance with a sensor that determines the charge level at the target, a control device that determines whether the charge is sufficient, and a wireless device that wirelessly transmits the determination result, and the deal may be determined based on charge status information transmitted from the wireless device to the laser irradiation device 1. Alternatively, if the purpose is to repel flying or harboring harmful birds and animals, the deal may be determined based on image analysis by the controller 70. In this case, the controller 70, for example, analyzes the images captured by the tracking camera 24 and determines whether the harmful bird or animal has been repelled from the observation range or whether the bird or animal has lost its ability to fly, and if either determination is positive, determines that the response has been completed.

[0040] If the determination in step S8 is YES and it is confirmed that the countermeasures have been completed, the controller 70 determines whether or not there are other targets (step S9). That is, the controller 70 determines whether or not there are any targets detected by the radar detector 110 other than the targets for which countermeasures have already been completed.

[0041] If the determination in step S9 is YES and the presence of another target is confirmed, the controller 70 repeats the processing from step S5 onwards to track and deal with the other target.

[0042] On the other hand, if the determination in step S9 is NO and it is confirmed that no other targets exist, the controller 70 executes a control mode (hereinafter referred to as the second mode) for closing the cover device 14. That is, the controller 70 drives the cover motor 43 in the closing direction to close the cover device 14 (step S10), and closes the air nozzle 51 to stop blowing of air W1 (step S11). By this second mode, the irradiation optical device 12 is covered and hidden by the cover device 14, and air blowing to the irradiation window 23 is stopped.

[0043] Next, a control operation will be described when the determination in step S1 is NO, that is, when the radar detector 110 is not in operation. In this case, the controller 70 determines whether or not there is a request to perform a dirt inspection on the irradiation window 23 (step S13). For example, the controller 70 determines that there is a request for a dirt inspection when a command to perform a dirt inspection is input from the operator via a predetermined input device.

[0044] If the determination in step S13 is NO, and it is confirmed that there is no request for a dirt inspection, the controller 70 maintains the second mode described above (step S20).

[0045] On the other hand, if the determination in step S13 is YES and it is confirmed that a dirt inspection is requested, the controller 70 drives the cover motor 43 in the opening direction to open the cover device 14 (step S14).

[0046] Next, the controller 70 determines whether or not the surface of the irradiation window 23 is contaminated beyond an allowable level based on the input information from the contamination sensor 17 (step S15).

[0047] If the determination in step S15 is YES and contamination exceeding the allowable level is confirmed, the controller 70 executes a control mode (hereinafter referred to as a third mode) in which the irradiation window 23 is washed with the washer fluid W2. That is, the controller 70 opens the liquid nozzle 61 to spray the washer fluid W2 onto the surface of the irradiation window 23 (step S16). In this third mode, the surface of the irradiation window 23 is washed with the washer fluid W2.

[0048] The cleaning in step S16 is continued until the contamination of the irradiation window 23 falls below an allowable level. When the contamination falls below an allowable level, the determination in step S15 becomes NO. Then, the controller 70 closes the liquid nozzle 61 to stop spraying the washer fluid W2 (step S17), and drives the cover motor 43 in the closing direction to close the cover device 14 (step S18). That is, the controller 70 switches the control mode from the third mode in which the irradiation window 23 is cleaned to the second mode in which the cover device 14 is closed.

[0049] The functions of each element, including the controller 70, disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, application-specific integrated circuits (ASICs), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuitry. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. Where hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or processor.

[0050] [Action and effect] As described above, in this embodiment, when a target is detected by the radar detector 110, the first mode is executed, in which the cover device 14 is opened and air W1 is blown onto the irradiation window 23 (see steps S3 and S4). The detection of a target means that there is a high possibility that irradiation of the target with the laser Lb will be required in the near future, that is, the necessity for laser irradiation is high. According to this embodiment, in which the first mode is selected in such a situation, the laser Lb can be accurately irradiated onto the target while preventing dirt from adhering to the irradiation window 23. In other words, in the laser irradiation device 1 of this embodiment, the controller 70 determines whether the necessity for laser irradiation is high or low according to the detection result of the radar detector 110, and selects whether to maintain each mode or switch to another mode based on the determination result.

[0051] That is, in this embodiment, the cover device 14 is open while the target is being detected. Therefore, when irradiation of the laser beam Lb is actually requested, i.e., when target tracking has converged, the laser beam Lb can be quickly irradiated through the already exposed irradiation window 23. However, when the cover device 14 is open, foreign matter such as dust, raindrops, or insects may adhere to the irradiation window 23, contaminating the irradiation window 23. If the irradiation window 23 becomes contaminated, some of the laser beam Lb may be absorbed by the foreign matter, causing localized heating of the irradiation window 23, potentially resulting in a significant temperature distribution across the irradiation window 23. Such a temperature distribution may change the pointing direction of the laser beam Lb as it passes through the irradiation window 23, reducing the irradiation accuracy of the laser beam Lb. In contrast, in this embodiment, air W1 is blown onto the irradiation window 23 from the air nozzle 51 while the cover device 14 is open. This blown air W1 protects the irradiation window 23 and prevents the irradiation window 23 from becoming contaminated. This makes it possible to improve the accuracy of irradiation of the laser Lb through the irradiation window 23, and to increase the hit rate of the laser Lb on the target.

[0052] On the other hand, when a target is not detected and there is no request for a contamination inspection, a second mode is executed in which the cover device 14 is closed (see steps S10 and S20). The absence of a target means that irradiation of the laser Lb on the target is not currently required, i.e., the need for laser irradiation is low. According to this embodiment, in which the second mode is selected in such a situation, the irradiation window can be kept clean until the next need for laser irradiation increases, thereby maintaining high irradiation accuracy of the laser Lb. For example, if the cover device 14 is left open when a target is not detected, such as while traveling to a destination, there is a high possibility that significant contamination will adhere to the irradiation window 23. In contrast, in this embodiment, the cover device 14 is closed when a target is not detected, so the cover device 14 can cover the irradiation optical system 12 and shield the irradiation window 23 from the outside world. This keeps the irradiation window 23 clean, so that the next time laser irradiation is requested, the laser Lb can be accurately irradiated from the clean irradiation window 23.

[0053] Furthermore, in this embodiment, if it is confirmed that dirt is adhering to the irradiation window 23, a third mode is executed in which washer fluid W2 is sprayed onto the irradiation window 23 from the liquid nozzle 61 (see step S16). With this configuration, dirt adhering to the irradiation window 23 can be washed away with the washer fluid W2, and the irradiation window 23 can be restored to a clean state.

[0054] [Variations] In the above embodiment, the irradiation optical device 12 and the support mechanism 13 are covered together by a dome-shaped cover device 14, but the cover device in the present disclosure may be any cover that can cover the irradiation window 23 of the irradiation optical device 12 or the front end surface 21a of the housing 21 that includes the irradiation window 23, and various modifications are possible within that scope.

[0055] An example of a modified cover device is shown in FIG. 13. The laser irradiation device 1A shown in FIG. 13 includes a cover device 114 that opens and closes the front end surface 21a of the housing 21, which includes the irradiation window 23. The cover device 114 includes a plate-shaped shielding plate 115 having an area corresponding to the front end surface 21a, a hinge 116 that pivots around an end of the shielding plate 115, and a motor (not shown) that rotates the shielding plate 115 around the hinge 116. The hinge 116 allows the shielding plate 115 to rotate as indicated by arrow A3 and is attached to the upper end of the front end surface 21a. By rotating around the hinge 116, the shielding plate 115 can be displaced between an open state indicated by a solid line in which the shielding plate 115 is disposed along the top surface of the housing 21 and a closed state indicated by a dashed line in which the shielding plate 115 covers the front end surface 21a of the housing 21. The structure for closing or opening the front end surface 21 a of the irradiation window 23 is not limited to the structure in which the shielding plate 115 is rotated by the hinge 116. For example, a shutter-like structure formed by connecting a plurality of plate-like members may be prepared, and the irradiation window 23 may be closed or opened by switching the structure between an expanded state in which it is expanded and a stored state in which it is stored by rolling up or shifting to one side. The opening and closing direction of the shielding plate 115 is not particularly limited as long as it is a direction in which the irradiation window 23 can be switched between a state in which it is covered by the shielding plate 115 and a state in which it is not covered.

[0056] 14A and 14B are diagrams showing a modification different from the modification shown in FIG. 13. The laser irradiation device 1B shown in FIGS. 14A and 14B includes a lower cover 214 provided below the irradiation optical device 12. The lower cover 214 is fixed between a pair of support legs 33 (see also FIG. 4) that support the irradiation optical device 12. The irradiation optical device 12 is supported by the support legs 33 (support mechanism 13) so that the front end surface 21a of the housing 21 can tilt to a position facing the lower cover 214. In other words, the Y-axis motor 35 (FIG. 10) of the support mechanism 13 tilts the irradiation optical device 12 to a position facing the front end surface 21a of the lower cover 214, thereby creating the state shown in FIG. 14B in which the lower cover 214 covers the front end surface 21a. On the other hand, when coverage by the lower cover 214 is not required, the Y-axis motor 35 exposes the front end surface 21a including the irradiation window 23 to the outside by directing the front end surface 21a of the irradiation optical device 12 to an appropriate position that does not face the lower cover 214 (see FIG. 14A). That is, in the modified example of FIGS. 14A and 14B, the lower cover 214 provided below the irradiation optical device 12 and the Y-axis motor 35 that tilts the irradiation optical device 12 form a cover device that switches between a state in which the lower cover 214 covers the irradiation window 23 and a state in which it does not cover the irradiation window 23.

[0057] As described above, the cover device in the present disclosure may include various devices intended to switch the front surface of the irradiation window 23 between an exposed state and a non-exposed state to the outside world.

[0058] In the above embodiment, the contamination prevention device is a device that prevents contamination of or removes contamination from the irradiation window 23. Three types of devices, namely, the cover device 14, the blower device 15, and the cleaning device 16, are provided as examples of this contamination prevention device. However, some of these devices may be omitted. It is also possible to prevent or remove contamination from the irradiation window 23 using devices other than the above three types of devices. For example, a wiper that wipes the surface of the irradiation window 23 may be provided as a cleaning device. The wiper may be provided together with a device that sprays washer fluid W2, such as the liquid nozzle 61, or a wiper alone may be provided as a cleaning device instead of a device that sprays washer fluid W2. In other words, the contamination prevention device in the present disclosure may be any device that can prevent contamination of or remove contamination from the irradiation window 23, and various devices or combinations thereof may be used as long as they meet this requirement. As illustrated in the above embodiment, when at least a device that sprays washer fluid W2 is combined with the blow device 15, in addition to each device performing the functions described so far, after the liquid nozzle 61 sprays the washer fluid W2, the blow device 15 can remove droplets of washer fluid W2 that have adhered to the irradiation window 23.

[0059] In the above embodiment, a blowing device 15 that blows air onto the irradiation window 23 is provided as an example of a blowing device in the present disclosure, but the gas blown from the blowing device is not limited to air, and a device that blows a gas other than air onto the irradiation window may also be used as the blowing device.

[0060] In the above embodiment, the contamination on the irradiation window 23 is detected using the contamination sensor 17, and the cleaning device 16 is activated in response to the detection of the contamination to clean the irradiation window 23. However, the cleaning device 16 may also be manually activated. In this case, the cleaning device 16 is activated and cleans the irradiation window 23 in response to an operation by an operator who visually inspects the irradiation window 23.

[0061] In the above embodiment, an example in which the laser irradiation device 1 is mounted on a vehicle 101 has been described. However, the laser irradiation device of the present disclosure can also be mounted on a moving body other than a vehicle, such as a ship or an aircraft. The laser irradiation device of the present disclosure can also be fixedly installed on a facility such as a building. Furthermore, the laser irradiation device of the present disclosure is not limited to a mounting position or mounting angle on a moving body or facility to which it is mounted. For example, the laser irradiation device 1 may be mounted on a structure other than the container 106 of the vehicle 101 so as to protrude in either the left or right direction. In this case, for example, the configuration shown in FIG. 13 can be suitably applied as a cover device.

[0062] In the above embodiment, an example has been described in which the radar detector 110 is mounted on the vehicle 101, but the radar detector 110 is not essential and may be omitted.

[0063] [summary] The above embodiment and its modifications can be summarized as follows.

[0064] The laser irradiation device includes a light source that generates a laser, an irradiator that includes a housing through which the laser from the light source passes and a window provided at the laser exit of the housing, and a dirt prevention device that prevents the window from becoming dirty.

[0065] In this embodiment, the dirt prevention device can keep the window clean, which can prevent the laser beam from changing its direction when passing through the window, thereby improving the accuracy of laser irradiation.

[0066] Preferably, the anti-fouling device includes a cover device for covering the window.

[0067] In this aspect, by covering the window with the cover device, it is possible to prevent the window from becoming dirty, and when laser irradiation is required, the cover device is opened to expose the window to the outside, allowing the laser to be irradiated appropriately through the exposed window.

[0068] The anti-fouling device may include a blower for blowing gas onto the window.

[0069] In this embodiment, it is possible to irradiate the laser through the window, while preventing the window from becoming dirty by blowing air.

[0070] Alternatively, the anti-fouling device may include a cleaning device that sprays a liquid onto the window.

[0071] In this embodiment, when dirt adheres to the window, the dirt can be washed away with the liquid.

[0072] The stain prevention device may include a cover device that covers the window, a blower device that blows gas onto the window, and a controller that controls the cover device and the blower device. In this case, it is preferable that the controller switch between a first mode in which the blower device blows gas without the cover device covering the window, and a second mode in which the cover device covers the window, depending on the need for laser irradiation.

[0073] In this aspect, for example, by selecting the first mode in a situation where laser irradiation is highly necessary, it is possible to accurately irradiate the laser while preventing dirt from adhering to the window. That is, by selecting the first mode, the cover device is opened and gas is blown onto the window, so the window can be exposed to the outside while being kept clean. Therefore, when laser irradiation is actually required, the laser can be irradiated quickly through the already exposed window. Furthermore, because the laser can be irradiated accurately through the clean window protected by gas, the laser's hit rate on the target can be increased.

[0074] In addition, when the need for laser irradiation is low, the second mode can be selected to close the cover device and isolate the window from the outside world, thereby keeping the window clean until the next time the need for laser irradiation increases.

[0075] The stain prevention device may further include a cleaning device that sprays liquid onto the window, in which case the controller executes a third mode in which the cleaning device sprays liquid when it is determined that the window is stained.

[0076] In this embodiment, the dirt adhering to the window can be washed away with the liquid, and the window can be restored to a clean state. [Explanation of symbols]

[0077] 1: Laser irradiation device 11: Laser oscillator (light source) 12: Irradiation optical device (irradiation device) 13:Support mechanism 14: Cover device 15: Blow device 16: Cleaning device 21: Housing 23: Irradiation window (window) 70: Controller Lb: Laser W1: Air (gas) W2: Washer fluid (liquid)

Claims

1. a light source that generates a laser; an irradiator including a housing through which a laser from the light source passes and a window provided at an exit of the housing for the laser; a dirt prevention device for preventing dirt from being accumulated on the window; The anti-fouling device comprises: a cover device for covering the window; a blower that blows gas onto the window; a controller for controlling the cover device and the blow device, The controller switches between a first mode in which the blowing device blows gas without the cover device covering the window, and a second mode in which the cover device covers the window, depending on the need for laser irradiation.

2. 2. The laser irradiation device according to claim 1, The stain prevention device further includes a cleaning device that sprays a liquid onto the window.

3. 3. The laser irradiation device according to claim 2, The laser irradiation device, wherein the controller executes a third mode in which liquid is sprayed from the cleaning device when adhesion of dirt to the window is confirmed.

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