JP7724130B2 - Laser irradiation device - Google Patents

Description

This disclosure relates to a laser irradiation device that emits a laser.

The laser irradiation device shown in Patent Document 1 below is known. This laser irradiation device includes a light source, a laser irradiation unit, and an optical system that guides the laser from the light source to the laser irradiation unit.

Patent No. 6654028

When emitting a laser from the laser irradiation unit, a window that allows the laser to pass through must be provided at the laser's irradiation port in order to maintain a clean and dry interior of the laser irradiation device. However, if the window is dirty, the laser will be refracted as it passes through the window, which could reduce the accuracy of the laser irradiation.

This disclosure was made in consideration of the above-mentioned circumstances, and aims to provide a laser irradiation device that can improve the accuracy of laser irradiation through a window.

To solve the above problem, one aspect of the present disclosure provides a laser irradiation device that includes a light source that generates a laser beam, an irradiator that includes a housing through which the laser beam 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.

The laser irradiation device disclosed herein allows for precise irradiation of the laser through a clean window.

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. FIG. 2 is a side view showing the high-power laser system when the cover device is in a closed state. FIG. 2 is a side view showing the details of the laser irradiation device. FIG. 2 is a perspective view showing the details of the laser irradiation device. FIG. 2 is a perspective view showing the laser irradiation device when the cover device is in an open state. FIG. 2 is a perspective view showing the laser irradiation device when the cover device is in a closed state. FIG. 2 is a side view showing the configuration of a blowing device and a cleaning device. FIG. 10 is a front view showing how air is blown from the blowing device. FIG. 10 is a front view showing how washer fluid is sprayed from the cleaning device. FIG. 2 is a functional block diagram showing a control system of the high-power laser system. 10 is a flowchart illustrating an example of a control operation executed by a controller of the high-power laser system. FIG. 1 is a diagram for explaining how a target is tracked using a tracking camera. FIG. 10 is a diagram for explaining how tracking converges. FIG. 10 is a side view of a laser irradiation device according to a modified example of the embodiment. FIG. 10 is a side view of a laser irradiation device according to another modified example of the embodiment. 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.

[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.

The laser irradiation device 1 is mounted on a vehicle 101, which is a mobile object. The vehicle 101 includes an engine 102 as a power source, wheels 103 rotated 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 laser irradiation device 1 described above is mounted on the container 106. The container 106 also includes a radar detector 110 that uses radar to detect targets. In other words, the high-power laser system of this embodiment is a mobile laser system equipped with the laser irradiation device 1 and radar detector 110 mounted on the vehicle 101. Note that, for convenience of the following explanation, in this embodiment, the up-down, left-right, front-rear, and horizontal directions of the vehicle 101 are defined as the up-down, left-right, front-rear, and horizontal directions of the driver sitting in the driver's seat of the vehicle 101.

The laser irradiation device 1 comprises a laser oscillator 11, an irradiation optical device 12, a support mechanism 13, and a cover device 14 shown in Figure 2. The laser oscillator 11 is a light source that generates the laser Lb shown in Figure 1. The irradiation optical device 12 is an irradiator that irradiates the laser Lb emitted from the laser oscillator 11 while guiding it 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 comprises an openable cover for covering the irradiation optical device 12.

In this embodiment, the cover device 14 and the blow device 15 and cleaning device 16, which will be described later, all correspond to "fouling prevention devices" in this disclosure. Preventing contamination in this disclosure includes not only preventing the adhesion of various foreign matter to the irradiation window 23, which will be described later, but also monitoring the adhesion of foreign matter to the irradiation window 23 and removing it.

The laser oscillator 11 is disposed inside the container 106, and the irradiation optical device 12 and support mechanism 13 are disposed on top of the container 106. The cover device 14 has a cover that can be extended and retracted from the container 106. That is, the cover device 14 can be switched between an open state shown in FIG. 1 in which the irradiation optical device 12 and 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 support mechanism 13 are concealed. The interior of the container 106 may be used not only as a storage room for the laser oscillator 11, but also as an operator's room where an operator who operates the laser irradiation device 1 is stationed.

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 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 supply 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. Fiber lasers are a type of electrically driven laser that oscillates using an optical fiber doped with a laser-active element, and have 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 semiconductor laser light 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.

3 and 4 are side and perspective views showing the details of the illumination optical device 12 and the support mechanism 13. The "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 the 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 the pivoting shaft 31a (described later) for rotating the illumination optical device 12, coincides with the vertical direction of the vehicle 101, so the direction in which the side of the illumination optical device 12 faces coincides with the horizontal direction of the vehicle 101. However, this may not be 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 roughly 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 focus and direct the laser beam Lb output from the laser oscillator 11 in the desired direction, and includes, for example, a focusing lens and a refractive lens. The irradiation window 23 is a transparent member made of a glass plate or the like that allows the laser beam Lb output from the optical module 22 to pass through, and is attached to the front end surface 21a of the housing 21, which is the exit for 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 to capture an image into the tracking camera 24. The irradiation window 23 corresponds to the "window" in this disclosure.

The irradiation optical device 12 emits a laser beam from the optical module 22 through the irradiation window 23 while its attitude is controlled so that it points toward the target photographed by the tracking camera 24. This allows the laser to be irradiated onto the target.

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 interior 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 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 the temperature rise that accompanies absorption of the laser.

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 around the Z axis in the direction of arrow A1, and tilt around the Y axis perpendicular to the Z axis in the direction of arrow A2. As mentioned 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.

Specifically, the support mechanism 13 includes a base 31, a rotating body 32, a pair of support legs 33 that support the illumination optical device 12 from both sides 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 rotating body 32 is a disk-shaped rotating body disposed on the base 31 and is pivotally supported on the base 31 via a pivot 31a extending in the Z-axis direction. The pair of support legs 33 protrude from the rotating body 32 above the vehicle 101, in other words, protrude to one side in the Z-axis direction, and are positioned to sandwich the illumination optical device 12 from both sides thereof. Each support leg 33 pivotally supports the illumination optical device 12 via a tilting shaft 33a extending in the Y-axis direction. The Z-axis motor 34 is an electric motor that rotates the rotating body 32 around the Z-axis as indicated by arrow A1. The Y-axis motor 35 is an electric motor that rotates the illumination optical device 12 around the Y-axis as indicated by arrow A2.

In response to the rotational drive of the rotating body 32 by the Z-axis motor 34, the irradiation optical device 12 rotates around the Z axis together with the support leg 33. In addition, in response to the rotational drive of the Y-axis motor 35, the irradiation optical device 12 tilts around the Y axis relative to the support leg 33. In this embodiment, the laser irradiation device 1 supports the irradiation optical device 12 on the support mechanism 13 in such a state that it can rotate and tilt, making it possible to orient the front end surface 21a, on which the irradiation window 23 and imaging window 25 are located, in all directions.

The irradiation optical device 12 and the laser oscillator 11 are connected via a light guide path 18, shown simply in Figure 4. The light guide path 18 is a path for introducing the laser Lb emitted from the laser oscillator 11 into the optical module 22 inside the irradiation optical device 12. When irradiating the target with the laser Lb, the laser Lb is introduced from the laser oscillator 11 into the optical module 22 via the light guide path 18. The laser Lb introduced into the optical module 22 is then guided to the outside through the irradiation window 23.

Figure 5 is a perspective view showing the laser irradiation device 1 when the cover device 14 is in an open state, and Figure 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-part structure and includes two element covers 41A and 41B that can rotate around a support shaft 42, and a cover motor 43 shown in Figure 10 that rotates both element covers 41A and 41B. Each of the element covers 41A and 41B has the shape of a spherical shell divided 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 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 connected to each of the element covers 41A and 41B via gears or the like, and is capable of rotating the element covers 41A and 41B simultaneously in opposite directions around the support shaft 42.

When closing the cover device 14 shown in FIG. 6, the cover motor 43 rotates each element cover 41A, 41B to a position where almost the entire element cover 41A, 41B protrudes above the container 106. This causes the element covers 41A, 41B to butt against each other above the container 106, resulting in a state where the element covers 41A, 41B are continuous across the semicircular dividing line B. This creates a dome-shaped closed cover device 14, which conceals the irradiation optics 12 and support mechanism 13 from the outside world of the laser irradiation device 1. On the other hand, when opening the cover device 14 shown in FIG. 5, the cover motor 43 rotates each element cover 41A, 41B to a position where most of the element covers 41A, 41B are housed within the container 106. This causes the spherical shell formed by the element covers 41A, 41B to open in the left-right direction of the vehicle 101, exposing the irradiation optics 12 and support mechanism 13 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. This is to ensure space for the above-mentioned light guide path 18 (Figure 4) that introduces the laser Lb to the irradiation optical device 12.

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 below, and FIG. 9 is a front view showing the positional relationship between the irradiation window 23 and the cleaning device 16 described below. The "side" here refers to the side of the irradiation optical device 12, as in FIG. 3 above. The "front" here refers to the surface 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 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 surface when the direction of laser Lb irradiation is forward of the irradiation optical device 12, i.e., the surface that is exposed to the outside air.

As shown in Figures 7 and 8, the blowing device 15 includes multiple air nozzles 51, an air supply source 52, and an air pipe 53. The multiple 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 in a circular pattern at equal intervals along the outer periphery of the irradiation window 23 with their nozzle openings facing the circular irradiation window 23 when viewed from the front. 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 air W1 to each air nozzle 51 through the air pipe 53.

Each air nozzle 51 can be switched between an open state in which pressurized air W1 is blown onto the irradiation window 23, and a closed state in which the blowing of the air W1 is stopped. Each air nozzle 51 is positioned so that the nozzle opening direction is at a different angle so that the air W1 can be blown toward the center of the irradiation window 23, which is circular in front view.

7 and 9, the cleaning device 16 includes multiple liquid nozzles 61, a liquid supply source 62, a liquid pipe 63, and a liquid receptacle 64. The multiple liquid nozzles 61 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 connects each liquid nozzle 61 to the liquid supply source 62. The liquid supply source 62 includes components such as a pump that pressure-feeds washer fluid W2 to each liquid nozzle 61 through the liquid pipe 63. Any type of washer fluid W2 can 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 preferably used.

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

The above-mentioned directions of spraying air W1 from the air nozzle 51 and spraying washer fluid W2 from the liquid nozzle 61 are merely examples. In particular, the liquid nozzle 61 is described as an example of a convenient positional relationship for spraying washer fluid W2 over 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 Figure 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 direction of spraying 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.

Figure 10 is a functional block diagram showing the control system of a high-power laser system including the laser irradiation device 1 described above. As shown in this diagram, the high-power laser system is equipped with 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.

The controller 70 acquires target position information 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 Y-axis motor 35 to control the attitude of the irradiation optical device 12. The controller 70 also drives the air nozzle 51 or 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.

The laser irradiation device 1 is equipped with 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 results from this dirt sensor 17 are input to the controller 70.

[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 (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.

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 the controller 70 activates the radar detector 110 upon receiving the activation command. When the radar detector 110 is in operation, that is, when the determination in step S1 is YES, the controller 70 determines whether a target has been detected by the radar detector 110 (step S2).

If step S2 returns YES and target detection 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 blown air W1.

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 is within the field of view of the tracking camera 24, and causes the tracking camera 24 to continuously photograph the target.

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

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

Next, the controller 70 determines whether 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 traversing target, if the target is moving, it is necessary to continuously track the target for a certain period of time and irradiate the target with the laser Lb. Therefore, whether the deal has been dealt with, i.e., whether to continue or halt the power supply, can be determined, for example, by whether the time the target and the laser sight X2 remain substantially aligned exceeds a predetermined 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. The deal may then be determined based on the 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 images captured by the tracking camera 24 to determine 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.

If step S8 returns YES and it is confirmed that the countermeasure has been completed, the controller 70 determines whether other targets exist (step S9). In other words, the controller 70 determines whether there are any targets detected by the radar detector 110 in addition to the target for which countermeasures have already been completed.

If step S9 returns 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.

On the other hand, if step S9 returns NO and it is confirmed that no other targets exist, the controller 70 executes a control mode (hereinafter referred to as the second mode) in which the cover device 14 is closed. 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 the blowing of air W1 (step S11). This second mode causes the irradiation optical device 12 to be covered and hidden by the cover device 14, and stops the air blow to the irradiation window 23.

Next, we will explain the control operation when the determination in step S1 is NO, i.e., when the radar detector 110 is not in operation. In this case, the controller 70 determines whether there is a request to conduct 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 conduct a dirt inspection is input by the operator via a specified input device.

If step S13 returns NO and it is confirmed that no dirt inspection is required, the controller 70 maintains the second mode described above (step S20).

On the other hand, if step S13 returns YES and a request for a dirt inspection is confirmed, the controller 70 drives the cover motor 43 in the opening direction to open the cover device 14 (step S14).

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

If step S15 returns YES and contamination exceeding the allowable level is confirmed, the controller 70 executes a control mode (hereinafter referred to as the third mode) in which the irradiation window 23 is washed with washer fluid W2. That is, the controller 70 opens the liquid nozzle 61 to spray 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 washer fluid W2.

The cleaning in step S16 continues until the contamination of the irradiation window 23 falls below an acceptable level. When the contamination falls below an acceptable level, the determination in step S15 becomes NO. The controller 70 then 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). In other words, 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.

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, ASICs (Application Specific Integrated Circuits), 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. In the case of a processor, where the hardware 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.

[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, i.e., 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 based on 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.

In other words, in this embodiment, the cover device 14 is open while the target is being detected. Therefore, when laser Lb irradiation is actually requested, i.e., when target tracking has converged, the laser 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, causing it to become contaminated. If dirt adheres to the irradiation window 23, some of the laser 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 Lb as it passes through the irradiation window 23, reducing the irradiation accuracy of the laser 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 it from becoming contaminated. This increases the accuracy of the laser Lb's irradiation through the irradiation window 23, thereby increasing the hit rate of the laser Lb on the target.

On the other hand, when a target is not detected and there is no request for a contamination inspection, the second mode is executed, in which the cover device 14 is closed (see steps S10 and S20). The fact that a target is not detected means that there is no immediate need to irradiate the target with the laser Lb, meaning that there is little need for laser irradiation. In this embodiment, in which the second mode is selected in such a situation, the irradiation window can be kept clean until the next time laser irradiation becomes necessary, 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 dirt will accumulate on 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 optics 12 and shield the irradiation window 23 from the outside world. This keeps the irradiation window 23 clean, allowing the laser Lb to be accurately irradiated from the clean irradiation window 23 the next time laser irradiation is requested.

In addition, in this embodiment, if dirt is found to be 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 washer fluid W2, restoring the irradiation window 23 to a clean state.

[Modification]
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.

An example of a modified cover device is shown in Figure 13. The laser irradiation device 1A shown in Figure 13 includes a cover device 114 that can open and close and cover the front end surface 21a of the housing 21, which is equipped with 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 the 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 it is positioned along the top surface of the housing 21, and a closed state indicated by a dashed line, in which it covers the front end surface 21a of the housing 21. The structure for closing or opening the front end surface 21a of the irradiation window 23 is not limited to a structure in which the shielding plate 115 is rotated by the hinge 116. For example, the irradiation window 23 may be closed or opened by preparing a shutter-like structure made up of multiple connected plate-like members and switching the structure between an expanded state in which it is expanded and a stored state in which it is retracted or pushed to one side. Furthermore, the opening and closing direction of the shielding plate 115 is not particularly limited, and may be any 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.

Figures 14A and 14B show a modified example different from the modified example shown in Figure 13. The laser irradiation device 1B shown in Figures 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 Figure 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 its housing 21 can be tilted to a position facing the lower cover 214. In other words, the Y-axis motor 35 (Figure 10) of the support mechanism 13 tilts the irradiation optical device 12 to a position where the front end surface 21a faces the lower cover 214, thereby creating the state shown in Figure 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 orients the front end surface 21a of the irradiation optical unit 12 to an appropriate position that does not face the lower cover 214, thereby exposing the front end surface 21a, including the irradiation window 23, to the outside (see FIG. 14A). That is, in the modified example of FIGS. 14A and 14B, the lower cover 214 provided below the irradiation optical unit 12 and the Y-axis motor 35 that tilts the irradiation optical unit 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.

As described above, the cover device in this 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.

In the above embodiment, the dirt prevention device is a device that prevents or removes dirt from the irradiation window 23. Three types of devices, the cover device 14, the blower device 15, and the cleaning device 16, are provided as examples of this dirt prevention device, but some of these devices may be omitted. It is also possible to prevent or remove dirt from the irradiation window 23 using devices other than the three types of devices described above. 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 in conjunction 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 dirt prevention device in this disclosure may be any device that can prevent or remove dirt 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 blower device 15, each device performs the functions described above, and after the liquid nozzle 61 sprays washer fluid W2, the blower device 15 can remove droplets of washer fluid W2 that have adhered to the irradiation window 23.

In the above embodiment, a blowing device 15 that blows air onto the irradiation window 23 was 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.

In the above embodiment, the dirt sensor 17 is used to detect dirt on the irradiation window 23, and the cleaning device 16 is activated in response to the detection of the dirt to clean the irradiation window 23. However, the cleaning device 16 may also be manually operated. In this case, the cleaning device 16 is activated in response to operation by an operator who visually inspects the irradiation window 23, and cleans the irradiation window 23.

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

In the above embodiment, an example was described in which the radar detector 110 was installed in the vehicle 101, but the radar detector 110 is not essential and may be omitted.

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

The laser irradiation device comprises 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.

In this embodiment, the anti-fouling device can keep the window clean. This prevents the laser's direction from changing when passing through the window, improving the laser's irradiation accuracy.

Preferably, the anti-fouling device includes a cover device that covers the window.

In this configuration, covering the window with the cover device prevents dirt from adhering to the window. Furthermore, 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.

The anti-fouling device may include a blower that blows gas onto the window.

In this manner, the laser can be irradiated through the window while preventing dirt from adhering to the window by blowing air.

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

In this manner, if dirt adheres to the window, the dirt can be washed away with liquid.

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 to irradiate the laser.

In this configuration, for example, by selecting the first mode in situations where there is a high need for laser irradiation, the laser can be accurately irradiated 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 world while remaining 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 accurately irradiated through the clean window protected by gas, the laser's hit rate on the target can be increased.

In addition, when there is little need for laser irradiation, the second mode can be selected to close the cover device and isolate the window from the outside world. This allows the window to remain clean until the next time there is a greater need for laser irradiation.

The dirt prevention device may further include a cleaning device that sprays liquid onto the window. In this case, the controller executes a third mode in which liquid is sprayed from the cleaning device when dirt is detected on the window.

In this manner, dirt adhering to the window can be washed away with liquid, restoring the window to a clean state.

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

Claims (3)

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. 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. 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.