Laser emitting device and control method for same

Abstract

The present invention comprises: a light source unit including a laser light source that emits laser light (L) toward a specific emission range (E1); a lighting control unit that performs lighting control of the laser light source; and a human detection unit that detects the presence of a human (H) in the emission range (E1) of the laser light L. The human detection unit includes an optical sensor and a sound wave sensor, and the lighting control unit controls to turn off or dim the laser light source when either the optical sensor or the sound wave sensor responds.

Description

Laser irradiation device and its control method

[0001] This application claims priority to Japanese Patent Application No. 2023-169020, filed on September 29, 2023, the contents of which are incorporated herein by reference.

[0002] In recent years, illumination light has been obtained using a laser light source such as a laser diode (LD) that can obtain high-brightness, high-power light. Furthermore, drawing on a road surface or the like has been performed by scanning the laser light emitted from the laser light source (see, for example, Patent Document 1 below).

[0003] Japanese Patent Application Publication No. 2020-122365

[0004] In order to improve the visibility of images in bright environments such as daytime, it is necessary to increase the output of the laser light when drawing.

[0005] On the other hand, when the output of the laser light is increased, in order to prevent the laser light from directly reaching the human eye, for example, a motion sensor is used to detect that a person has entered the irradiation range of the laser light, and the laser light source is turned off. This makes it possible to prevent people from looking directly at the laser light.

[0006] However, some motion sensors are prone to false detection due to the influence of external light in bright environments, and some motion sensors lose sensitivity in environments such as rainy weather and strong winds. On the other hand, motion sensors that are less affected by the external environment (such as TOF, cameras, LiDAR, and millimeter-wave radar) are relatively expensive, which increases costs.

[0007] An aspect of the present invention provides a laser irradiation device and a control method thereof that can appropriately turn off or dim a laser light source when a person enters the irradiation range of the laser light.

[0008] The present invention provides the following aspects: [1] A laser irradiation device comprising: a light source unit including a laser light source that irradiates a laser beam toward a specific irradiation area; an on-off control unit that controls on-off of the laser light source; and a human detection unit that detects the presence of a human in the irradiation area of ​​the laser beam, wherein the human detection unit includes an optical sensor and an acoustic sensor, and the on-off control unit controls to turn off or dim the laser light source when either the optical sensor or the acoustic sensor reacts. [2] The laser irradiation device described in [1], wherein the human detection unit stops detection by the optical sensor when the illuminance of external light in the irradiation area of ​​the laser beam exceeds a threshold. [3] The laser irradiation device described in [1], wherein the optical sensor and the acoustic sensor react in a detection area surrounding the irradiation area of ​​the laser beam. [4] The laser irradiation device described in [3], wherein the optical sensor and the acoustic sensor react in a detection area surrounding the scanning area of ​​the laser beam. [5] The laser irradiation device according to [4], characterized in that the sonic wave sensor reacts in a detection range surrounding the detection range of the optical sensor. [6] The laser irradiation device according to [1], characterized in that the optical sensor is an IR sensor and the sonic wave sensor is a sonar sensor. [7] The laser irradiation device according to [1], characterized in that the light source unit includes a MEMS mirror that performs drawing in the irradiation range while scanning the laser light emitted from the laser light source. [8] The laser irradiation device according to [1], which is mounted on a vehicle and characterized in that the light source unit irradiates the laser light emitted from the laser light source toward a road surface.[9] A laser irradiation device comprising: a light source unit including a laser light source that irradiates a laser beam toward a specific irradiation range; an on / off control unit that controls the on / off of the laser light source; an optical sensor and an acoustic wave sensor that detect the presence of a person within the irradiation range of the laser beam; an external light illuminance unit that detects the surrounding environment; and a driver position detection unit that detects whether the driver is inside the vehicle, the method comprising: a first step of turning on a MEMS mirror; a second step of detecting whether an external light illuminance threshold is exceeded; a third step of the on / off control unit turning off or dimming the laser light source to stop drawing the road surface when either the optical sensor or the acoustic wave sensor reacts; a fourth step of detecting that the driver is inside the vehicle; and a fifth step of turning off the MEMS mirror drive after detecting that the driver is inside the vehicle.

[10] The method for controlling a laser irradiation device described in [9], wherein in the third step, the human presence detection unit stops detection by the optical sensor when the illuminance of external light in the irradiation range of the laser light exceeds a threshold value.

[0009] As described above, according to the aspects of the present invention, a laser irradiation device and a control method thereof are provided that are capable of appropriately turning off or dimming the laser light source when a person enters the irradiation range of the laser light.

[0010] 1 is a schematic diagram showing an example of road surface drawing by a laser irradiation device according to one embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a laser irradiation device. FIG. 3 is a schematic diagram showing the configuration of a light source unit provided in a laser irradiation device. FIG. 4 is a schematic diagram showing the irradiation range and detection range of a laser irradiation device installed on a door mirror of a vehicle, viewed from the side. FIG. 5 is a schematic diagram showing the irradiation range and detection range of a laser irradiation device installed on a door mirror of a vehicle, viewed from above. FIG. 6 is a flowchart for explaining the lighting control of a laser light source during road surface drawing by a laser irradiation device. FIG. 7 is a schematic diagram showing a case where the detection range of an IR sensor and the detection range of a sonar sensor are made different. FIG. 8 is a schematic diagram showing the irradiation range and detection range of a laser irradiation device installed on a street lamp.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings used in the following description, the dimensions of the components may be shown at different scales to make them easier to see, and the dimensional ratios of the components may not necessarily be the same as those in reality.

[0012] As an embodiment of the present invention, a laser irradiation device 1 shown in, for example, FIGS. 1 to 8 will be described.

[0013] FIG. 1 is a schematic diagram showing an example of road surface drawing using a laser irradiation device 1. FIG. 2 is a block diagram showing the configuration of the laser irradiation device 1. FIG. 3 is a schematic diagram showing the configuration of a light source unit 4 provided in the laser irradiation device 1. FIG. 4 is a schematic diagram showing an irradiation range E1 and a detection range E2 of the laser irradiation device 1 installed on the door mirror 101 of the vehicle 100, as viewed from the side. FIG. 5 is a schematic diagram showing an irradiation range E1 and a detection range E2 of the laser irradiation device 1 installed on the door mirror 101 of the vehicle 100, as viewed from above. FIG. 6 is a flowchart for explaining the lighting control of the laser light source 2 during road surface drawing using the laser irradiation device 1. FIG. 7 is a schematic diagram showing a case where the detection range E3 of the IR sensor 5 and the detection range E4 of the sonar sensor 6 are different. FIG. 8 is a schematic diagram showing the irradiation range E1 and the detection range E2 of the laser irradiation device 1 installed on a street light 200.

[0014] In addition, in the drawings shown below, an XYZ Cartesian coordinate system is set up, with the X-axis direction representing the fore-and-aft direction (length direction) of vehicle 100, the Y-axis direction representing the left-and-right direction (width direction) of vehicle 100, and the Z-axis direction representing the up-and-down direction (height direction) of vehicle 100.

[0015] 1, the laser irradiation device 1 of this embodiment is configured to apply the present invention to a vehicle drawing device installed on a door mirror 101 of a vehicle 100. That is, the laser irradiation device 1 performs road surface drawing by projecting a drawing pattern P, such as letters or an image, using laser light L that is irradiated toward a road surface T on the side of the vehicle when the vehicle is stopped.

[0016] Specifically, as shown in Figures 1, 2 and 3, this laser irradiation device 1 includes a light source unit 4 including a laser light source 2 and a MEMS (Micro-Electro-Mechanical Systems) mirror 3, a human detection unit 7 including an IR sensor 5 and a sonar sensor 6, and a lighting control unit 8 electrically connected to the light source unit 4 and the human detection unit 7.

[0017] The laser light source 2 is configured by an LD package including, for example, a red LD chip that emits red light, a green LD chip that emits green light, and a blue LD chip that emits blue light. The LD package also includes, for example, a first dichroic mirror that reflects blue light, a second dichroic mirror that reflects green light and transmits blue light, and a third dichroic mirror that reflects blue and green light and transmits red light, and emits each color light coaxially.

[0018] This makes it possible for the laser light source 2 to arbitrarily adjust the color tone (emission color) of the laser light L obtained by combining (mixing) these colored lights while controlling the proportions of red light, green light, and blue light emitted by each LD chip in the LD package.

[0019] The MEMS mirror 3 is a movable mirror that uses MEMS technology, and controls the reflection direction of the laser light L emitted from the laser light source 2 while oscillating in two-dimensional directions within the plane.

[0020] In the light source unit 4, the laser light L emitted from the laser light source 2 is scanned by the MEMS mirror 3, and the laser light L is irradiated from the door mirror 101 toward the road surface T on the side of the vehicle. This makes it possible to draw a road surface image within the irradiation range of the laser light L.

[0021] The IR sensor 5 is a type of optical sensor that functions as a human presence sensor that detects infrared rays (IR) from heat emitted by people or reflected light. The IR sensor 6 can be, for example, a pyroelectric IR sensor or an infrared reflective sensor that combines an infrared LED and a photodiode.

[0022] The sonar sensor 6 is a type of sonic wave sensor that functions as a human detection sensor by emitting ultrasonic waves and detecting the ultrasonic waves that hit a person and are reflected back.

[0023] As shown in Figures 4 and 5, the human presence detection unit 7 is able to detect the presence of a human H in the irradiation range E1 of the laser light L by the IR sensor 5 and sonar sensor 6 reacting in the detection range E2 surrounding the irradiation range E1 of the laser light L.

[0024] The IR sensor 5 and the sonar sensor 6 are human detection sensors that primarily detect humans H who enter the irradiation range E1 of the laser light L, but they can also detect animals other than humans H, such as pets. In particular, children, dogs, cats, and the like that are shorter than the door mirror 101 may look directly at the laser light L.

[0025] The lighting control unit 8 is made up of a microcomputer such as a CPU, and controls the laser light source 2 to switch between lighting (ON) and extinguishing (OFF).

[0026] In addition to switching on / off the laser light source 2, the lighting control unit 8 may also perform gradation control of the light amount and color tone of the laser light L emitted from the laser light source 2. For example, the lighting control unit 8 may perform gradation control (dimming) to reduce the light amount of the laser light L emitted from the laser light source 2 so that the brightness is safe for human eyes.

[0027] The lighting control unit 8 is also electrically connected to an illuminance sensor 50 mounted on the vehicle 100. The illuminance sensor 50 detects the illuminance (brightness) of external light outside the vehicle, and when the illuminance of external light exceeds a threshold value, the detected signal is supplied to the lighting control unit 8.

[0028] The threshold value is set to an appropriate external light illuminance value for the IR sensor 5 to function as a human presence sensor (e.g., 30,000 Lux or more on a cloudy day, 70,000 Lux or more on a sunny day), since the higher the external light illuminance, the more likely the IR sensor 5 is to make a false detection.

[0029] The illuminance sensor 50 is not necessarily limited to a configuration in which it is mounted on the vehicle 100, but may be a configuration in which it is mounted on the laser irradiation device 1, for example.

[0030] Furthermore, in the laser irradiation device 1 of this embodiment, instead of the above-mentioned illuminance sensor 50, a configuration may be adopted in which, when it is determined that the external light illuminance exceeds a threshold value based on external light illuminance information supplied via a communication unit mounted on the vehicle 100, the signal is supplied to the lighting control unit 8.

[0031] Regarding the ambient light illuminance information, it is possible to determine that the ambient light illuminance has exceeded a threshold value, for example, based on the position information of the vehicle 100 and weather information at that position. Alternatively, when it is determined that the sensitivity of the IR sensor 5 has decreased, a signal indicating this may be supplied to the lighting control unit 8.

[0032] When performing road surface drawing, the laser irradiation device 1 of this embodiment performs an initial operation before starting road surface drawing, for example, according to the flowchart shown in FIG.

[0033] Specifically, as shown in step S101 of FIG. 6, it is detected that the key lock of the vehicle 100 has been released or that the driver has approached the vehicle 100.

[0034] 6, the power is turned on for the illuminance sensor 50, the IR sensor 5, the sonar sensor 6, etc. At this step 102, processing of the signals detected by each sensor has not yet started.

[0035] As another type of sensing, the power may be turned on for a driver position detection unit (not shown) that can detect the presence of a driver inside the vehicle 100. The driver position detection unit may be a combination of one or more of a door contact sensor that detects whether the door on the driver's seat side is open or closed, an engine start sensor that detects that the engine is running, and a sensor (heat detection type, pressure detection type, etc.) that detects that a person is sitting in the driver's seat.

[0036] Next, as shown in step S103 of FIG. 6, the light source unit 4 starts driving the MEMS mirror 3 (ON) and, with the laser light source 2 turned off (OFF), is set in a state where scanning by the MEMS mirror 3 can be started.

[0037] The MEMS mirror 3 is driven early because it takes time to prepare for irradiation, but if it is to be started up instantly, it may be driven after step S201 in FIG. 6, which will be described later.

[0038] As shown in step S201 of FIG. 6, the lighting control unit 8 determines whether the external illuminance is equal to or less than a threshold value.

[0039] If it is determined that the external illuminance exceeds the threshold (NO), the process proceeds to step S205 in FIG. 6, where the human detection unit 7 stops detection by the IR sensor 5 (OFF) and continues detection only by the sonar sensor 6 (ON).

[0040] Specifically, the sonar sensor 6 starts receiving the detection signal. The IR sensor 5 stops detecting the object, meaning that the power supply to the IR sensor 5 remains ON, but reception of only the detection signal is turned OFF.

[0041] Alternatively, the power supply to the IR sensor 5 may be turned off. If the external illuminance again becomes equal to or less than the threshold value in the loop, the power supply to the IR sensor 5 is restarted (turned on).

[0042] Next, if the sonar sensor 6 reacts, the process proceeds to step S203 in Figure 6, where it is determined that a human H is present within the detection range E2 of the human presence detection unit 7, and the laser light source 2 is turned off (OFF), and road surface drawing is not started (the drive of the MEMS mirror 3 continues to remain ON).

[0043] On the other hand, if it is determined in step S205 of Figure 6 that there is no reaction with either sonar sensor 6 (No), the process proceeds to step S206 of Figure 6, where it is determined that no human H is present within the detection range E2 of the human presence detection unit 7, the laser light source 2 is turned on, and road surface drawing is started by scanning the laser light L of the laser light source 2 with the MEMS mirror 3.

[0044] On the other hand, if it is determined that the external illuminance is equal to or lower than the threshold (YES), the process proceeds to step S202 in Fig. 6, where the human detection unit 7 starts detection (turns both ON) with the IR sensor 5 and the sonar sensor 6. Specifically, the sonar sensor 6 and the IR sensor 5 are both set to a state in which they can start receiving detection signals.

[0045] Next, as shown in step S202 of FIG. 6, it is determined whether or not either the IR sensor 5 or the sonar sensor 6 has reacted.

[0046] If it is determined that either the IR sensor 5 or the sonar sensor 6 has reacted (Yes), the process proceeds to step S203 in Figure 6, and the lighting control unit 8 controls the laser light source 2 to be turned off (OFF) and the road surface drawing to be stopped (the drive of the MEMS mirror 3 continues to be ON).

[0047] In other words, if either the IR sensor 5 or the sonar sensor 6 reacts, it is determined that a human H is present within the detection range E2 of the human presence detection unit 7, the laser light source 2 is turned off, and road surface drawing is stopped (the drive of the MEMS mirror 3 continues to remain ON).

[0048] On the other hand, if it is determined in step S202 of Figure 6 that there is no reaction with either sonar sensor 6 (No), the process proceeds to step S204 of Figure 6, where it is determined that no human H is present within the detection range E2 of the human presence detection unit 7, the laser light source 2 is turned on, and road surface drawing is started by scanning the laser light L of the laser light source 2 with the MEMS mirror 3.

[0049] Then, the process returns to step S201, and steps S201 to S206 are repeated until the driver approaches the vehicle 100 and enters the detection range E2 of the human detection unit 7.

[0050] Next, as shown in step S207 of Fig. 6, if the driver reacts to the human detection unit, approaches the vehicle, and it is detected that the driver is inside the vehicle, there is no longer any need to perform road surface drawing, so the drive of the MEMS mirror 3 is also turned off as shown in step S208 of Fig. 6. Since it takes time for the MEMS mirror 3 to prepare for irradiation, it is better not to turn off the drive until there is no longer any need to use road surface drawing.

[0051] On the other hand, if the start-up occurs instantaneously, the driving of the MEMS mirror 3 may be turned off immediately after the road surface drawing is stopped. The driver position detection unit detects whether or not a driver is present in the vehicle 100. Furthermore, as shown in step S209 in Figure 6, the sensing power supply is also turned off, and the flow of this embodiment ends.

[0052] As described above, in the laser irradiation device 1 of this embodiment, when either the IR sensor 5 or the sonar sensor 6 reacts during the above-mentioned road surface drawing, the lighting control unit 8 turns off (OFF) the laser light source 2 and controls the road surface drawing to stop.

[0053] The laser irradiation device 1 of this embodiment uses relatively inexpensive human presence sensors, the IR sensor 5 and the sonar sensor 6. Furthermore, by utilizing the difference in characteristics between the IR sensor 5, which is an optical sensor, and the sonar sensor 6, which is an acoustic sensor, it is possible to improve detection accuracy without being affected by the external environment.

[0054] That is, among the motion sensors, the IR sensor 5 is more likely to make false detections in the above-mentioned bright environment due to the influence of external light, whereas the sonar sensor 6 is not affected by external light.

[0055] Therefore, in the laser irradiation device 1 of this embodiment, when the illuminance of external light in the detection range E2 of the human detection unit 7 exceeds the threshold value, detection by the IR sensor 5 is stopped and detection by the sonar sensor 6 is performed.

[0056] This makes it possible to appropriately turn off or dim the above-mentioned laser light source 2 when a human H enters the detection range E2 of the human detection unit 7 without being affected by external light even in bright environments such as daytime.

[0057] On the other hand, the sensitivity of the sonar sensor 6 may decrease due to attenuation of ultrasonic waves in environments such as rainy weather or strong winds, whereas the sensitivity of the IR sensor 5 does not decrease in such environments.

[0058] Therefore, in the laser irradiation device 1 of this embodiment, even if a false detection occurs by the sonar sensor 6 due to a decrease in the sensitivity of the sonar sensor 6, the IR sensor 5 will react when a human H enters the detection range E2 of the human detection unit 7, so detection is possible even in environments such as rainy weather or strong winds.

[0059] This makes it possible to appropriately turn off or dim the above-mentioned laser light source 2 when a human H enters the detection range E2 of the human detection unit 7, even in environments such as rainy weather or strong winds.

[0060] As described above, in the laser irradiation device 1 of this embodiment, by using the relatively inexpensive IR sensor 5 and sonar sensor 6, it is possible to appropriately turn off or dim the laser light source 2 while maintaining detection accuracy when a human H enters the irradiation range E1 of the laser light L without being affected by the external environment.

[0061] The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0062] Specifically, in the above embodiment, a configuration in which the laser irradiation device 1 is installed on the door mirror 101 of the vehicle 100 is exemplified, but it is also possible to configure the laser irradiation device 1 to be installed, for example, around the door, on the side, on the top or bottom of the vehicle 100.

[0063] Furthermore, in the above embodiment, the detection ranges E2 of the IR sensor 5 and the sonar sensor 6 that constitute the human detection unit 7 are approximately the same range, but the detection ranges E2 do not necessarily have to coincide, and there may be a deviation of the detection ranges E2 of several centimeters to several tens of centimeters.

[0064] 7, the laser irradiation device 1 may be configured such that the IR sensor 5 reacts in a detection range E3 that surrounds the irradiation range E1 of the laser light L, and the sonar sensor 6 reacts in a detection range E4 that surrounds the detection range E3 of the IR sensor 5. In other words, FIG. 7 shows a case in which the detection range E4 of the sonar sensor 6 is wider than the detection range E3 of the IR sensor 5.

[0065] The three-dimensional detection range E3 of the IR sensor 5 is set to surround the three-dimensional irradiation range E1 of the laser light L, but it may be set to surround at least the three-dimensional scanning range of the laser light L. This makes it possible to prevent the person H from looking directly at the laser light L even if the person H were to look into the light source unit 4, by causing the IR sensor 5 to react.

[0066] In addition, since an IR sensor 5 having a detection range E3 equivalent to the detection range E4 of the sonar sensor 6 is relatively expensive, it is possible to reduce costs by using an IR sensor 5 having a detection range E3 narrower than the detection range E4 of the sonar sensor 6.

[0067] On the other hand, by setting the three-dimensional detection range E4 of the sonar sensor 6 wider so as to surround the three-dimensional detection range E3 of the IR sensor 5, it is possible to react quickly to a person H who suddenly appears on the road on a bicycle or motorcycle, for example, and therefore to construct a safer eye-safe system.

[0068] Furthermore, the three-dimensional detection range E3 of the IR sensor 5 does not need to completely surround the three-dimensional irradiation range E1 of the laser light L; for example, even if it does not surround a portion of the irradiation range E1 on the vehicle 100 side, a person H will not approach from the vehicle 100 side, and this will not have a negative effect on the human detection unit 7.

[0069] Furthermore, in the above embodiment, a laser irradiation device 1 mounted on a vehicle 100 is exemplified, but the laser irradiation device 1 can also be applied to a road surface drawing device that is installed on a street light 200, as shown in Figure 8, and draws the road surface while irradiating laser light L toward the road surface T.

[0070] Furthermore, the laser irradiation device to which the present invention is applied is not limited to the case where drawing is performed on the road surface T described above, but can also be applied to drawing devices that draw on, for example, wall surfaces or screens.

[0071] Furthermore, the laser irradiation device to which the present invention is applied is not limited to the above-mentioned drawing device, but can also be applied to lighting devices such as vehicle lamps that use a laser light source to irradiate illumination light onto a road surface T, etc.

[0072] REFERENCE SIGNS LIST 1...laser irradiation device 2...laser light source 3...MEMS mirror 4...light source section 5...IR sensor (optical sensor) 6...sonar sensor (sound wave sensor) 7...human detection section 8...lighting control section 50...illuminance sensor 100...vehicle 101...door mirror 200...street light E1...irradiation range E2...detection range L...laser light H...human T...road surface

Claims

1. A laser irradiation device comprising: a light source unit including a laser light source that irradiates laser light toward a specific irradiation range; an illumination control unit that controls the illumination of the laser light source; and a human detection unit that detects the presence of a human within the irradiation range of the laser light, wherein the human detection unit includes an optical sensor and an acoustic sensor, and the illumination control unit controls the laser light source to be turned off or dimmed when either the optical sensor or the acoustic sensor reacts.

2. The laser irradiation device according to claim 1, wherein the human detection unit stops detection by the optical sensor when the illuminance of external light in the irradiation range of the laser light exceeds a threshold value.

3. The laser irradiation device according to claim 1, wherein the optical sensor and the sonic sensor react within a detection range surrounding the irradiation range of the laser light.

4. The laser irradiation device according to claim 3, wherein the optical sensor and the sonic sensor react within a detection range surrounding the scanning range of the laser light.

5. The laser irradiation device according to claim 4, wherein the sonic sensor reacts within a detection range surrounding the detection range of the optical sensor.

6. The laser irradiation device according to claim 1, characterized in that the optical sensor is an IR sensor and the acoustic sensor is a sonar sensor.

7. The laser irradiation device according to claim 1, wherein the light source unit includes a MEMS mirror that performs drawing within the irradiation range while scanning the laser light emitted from the laser light source.

8. A laser irradiation device as described in claim 1, which is mounted on a vehicle and characterized in that the light source unit irradiates the laser light emitted from the laser light source toward a road surface.

9. A method for controlling a laser irradiation device comprising: a light source unit including a laser light source that irradiates laser light toward a specific irradiation range; an illumination control unit that controls the illumination of the laser light source; an optical sensor and an acoustic sensor that detect the presence of a human being within the irradiation range of the laser light; an external light illuminance unit that detects the surrounding environment; and a driver position detection unit that detects whether the driver is inside the vehicle, the method comprising: a first step of driving a MEMS mirror ON; a second step of detecting whether a threshold for external light illuminance is exceeded; a third step of the illumination control unit turning off or dimming the laser light source to stop road surface drawing when either the optical sensor or the acoustic sensor reacts; a fourth step of detecting that the driver is inside the vehicle; and a fifth step of turning off the MEMS mirror drive after detecting that the driver is inside the vehicle.

10. A method for controlling a laser irradiation device as described in claim 9, characterized in that in the third step, when the external light illuminance in the irradiation range of the laser light exceeds a threshold value, detection by the optical sensor is stopped.

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