Spot illumination device and spot illumination method

Abstract

A spot illumination device (10) provides spot illumination directed at an illumination target located closer to a host vehicle (1) than at least the illumination distance of a passing beam of the host vehicle (1). An illumination target information acquisition unit (11) of the spot illumination device (10) acquires information pertaining to the location of the illumination target. When the illumination target is moving and the distance from the host vehicle 1 to the illumination target is a predetermined threshold value or less, an illumination control unit (12) of the spot illumination device (10) widens the illumination range of the spot illumination for the illumination target as compared to when the threshold value is exceeded.

Description

Spot lighting device and spot lighting method

[0001] The present disclosure relates to a lighting system for a vehicle, and more particularly to spot lighting that illuminates an object that should be recognized by a driver.

[0002] As a method for quickly alerting a vehicle driver to the presence of an object that should be recognized, spot lighting that locally illuminates the object has been proposed (for example, see Patent Document 1 below).

[0003] Japanese Patent Application Laid-Open No. 2022-153963

[0004] When the illumination target of a spotlight is a moving object, the direction of the spotlight needs to follow the position of the illumination target (relative position from the vehicle). In this case, even if the movement distance of the illumination target is the same, when the illumination target moves close to the vehicle, the direction of the spotlight needs to be moved more than when the illumination target moves farther away. Therefore, when the illumination target moves close to the vehicle, the local illumination range of the spotlight moves in a complicated manner, which may cause a flickering sensation to the driver and reduce the visibility of the illumination target.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a spot lighting device that can suppress flickering that the driver perceives due to the movement of the spot lighting even when the target illuminated by the spot lighting moves near the vehicle.

[0006] The spot lighting device according to the present disclosure provides spot lighting directed at an illumination target located at least closer to the vehicle than the illumination distance of the vehicle's passing lights, and includes an illumination target information acquisition unit that acquires information related to the position of the illumination target, and a lighting control unit that widens the illumination range of the spot lighting for the illumination target when the illumination target is moving and the distance from the vehicle to the illumination target is equal to or less than a predetermined threshold value compared to when the distance exceeds the threshold value.

[0007] According to the spot lighting device of the present disclosure, spot lighting with a wide lighting range is performed when the distance from the vehicle to the lighting target is short, so that even when the lighting target moves near the vehicle, the driver is prevented from feeling flickering due to the movement of the spot lighting.

[0008] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0009] 1 is a block diagram showing a configuration of a spot lighting system according to a first embodiment. FIG. 2 is a diagram for explaining the operation of the spot lighting system according to the first embodiment. FIG. 3 is a diagram for explaining switching control between wide-area spot lighting and narrow-area spot lighting having a hysteresis characteristic. FIG. 4 is a flowchart showing the operation of a spot lighting device according to the first embodiment. FIG. 5 is a diagram for explaining the operation of a spot lighting system according to a first modification of the first embodiment. FIG. 6 is a diagram showing an example of a relationship between a distance from a host vehicle to an illumination target and a width of an illumination range of spot lighting in the first modification of the first embodiment. FIG. 7 is a diagram showing an example of a relationship between a distance from a host vehicle to an illumination target and a width of an illumination range of spot lighting in the first modification of the first embodiment. FIG. 8 is a flowchart showing the operation of a spot lighting device according to a first modification of the first embodiment. FIG. 9 is a flowchart showing the operation of a spot lighting device according to a second modification of the first embodiment. FIG. 10 is a flowchart showing the operation of a spot lighting device according to a third modification of the first embodiment. FIG. 11 is a flowchart showing the operation of a spot lighting device according to a fourth modification of the first embodiment. FIG. 12 is a flowchart showing the operation of a spot lighting device according to a fifth modification of the first embodiment. FIG. 13 is a block diagram showing a configuration of a spot lighting system according to a sixth modification of the first embodiment. FIG. 14 is a diagram for explaining the operation of a spot lighting system according to a second embodiment. FIG. 15 is a flowchart showing the operation of a spot lighting device according to the second embodiment. FIG. 1 is a diagram for explaining an operation of a spot lighting system according to embodiment 3. FIG. 2 is a flowchart showing an operation of a spot lighting device according to embodiment 3. FIG. 3 is a block diagram showing a configuration of a spot lighting system according to embodiment 4. FIG. 4 is a diagram for explaining an operation of the spot lighting system according to embodiment 1. FIG. 5 is a diagram for explaining an operation of the spot lighting system according to embodiment 1. FIG. 6 is a diagram showing an example of a hardware configuration of a spot lighting device. FIG. 7 is a diagram showing an example of a hardware configuration of a spot lighting device.

[0010] <First Embodiment> Fig. 1 is a block diagram showing the configuration of a spot lighting system according to the first embodiment. The spot lighting system according to the first embodiment includes a spot lighting device 10 mounted on a vehicle 1, and a lighting device 21 and a periphery detection device 22 of the vehicle 1 connected thereto. Hereinafter, the vehicle 1 mounted with the spot lighting device 10 will be referred to as the "host vehicle." However, the spot lighting device 10 does not need to be permanently installed on the host vehicle 1, and may be a device independent of the host vehicle 1.

[0011] The lighting device 21 is a light source for spot lighting.

[0012] The periphery detection device 22 detects illumination targets of spotlights present in the vicinity of the vehicle 1, and is composed of, for example, a camera, a ToF (Time of Flight) sensor (radar, LiDAR (Light Detection and Ranging), sonar, etc.). Examples of illumination targets of spotlights include obstacles, pedestrians, and other vehicles (including motorcycles and bicycles), but any feature that the driver should be aware of may be used. The periphery detection device 22 provides information on the detected illumination targets (hereinafter referred to as "illumination target information") to the spotlight device 10. The illumination target information includes at least information related to the position of the illumination target (e.g., distance and direction from the vehicle 1). In addition to information related to the position of the illumination target, the illumination target information may also include information such as the size, type, moving speed, and moving direction of the illumination target.

[0013] The spotlight device 10 controls the lighting device 21 to provide spotlight on the illumination target based on the illumination target information acquired from the periphery detection device 22. The spotlight device 10 includes an illumination target information acquisition unit 11 and an illumination control unit 12.

[0014] The illumination target information acquisition unit 11 acquires illumination target information from the periphery detection device 22 .

[0015] Based on the illumination target information acquired by the illumination target information acquisition unit 11, the illumination control unit 12 controls the lighting device 21 to provide spot illumination to illumination targets located at least closer to the vehicle 1 than the illumination distance of the vehicle's passing lights (so-called "low beams"). The illumination distance of the passing lights is assumed to be about 40 m. In other words, the illumination control unit 12 provides spot illumination to illumination targets located within a radius of about 40 m from the vehicle 1.

[0016] In this embodiment, the lighting control unit 12 performs spot lighting on an illumination target that may collide with the vehicle 1. Conversely, if there is no possibility that the illumination target may collide with the vehicle 1, spot lighting is not performed on the illumination target.

[0017] The lighting control unit 12 can control the lighting position, lighting range, and lighting aspect (e.g., illuminance, hue, blinking cycle, etc.) of the spot lighting. In this embodiment, the lighting control unit 12 controls the width of the lighting range of the spot lighting depending on the distance from the host vehicle 1 to the lighting target. Specifically, as shown in FIG. 2 , when the distance from the host vehicle 1 to the lighting target 2 is greater than a predetermined threshold, the lighting control unit 12 narrows the lighting range 3 of the spot lighting for the lighting target 2, and when the distance is equal to or less than the threshold, the lighting control unit 12 widens the lighting range 3 of the spot lighting for the lighting target 2 when the distance from the host vehicle 1 to the lighting target 2 is equal to or less than the threshold, compared to when the distance exceeds the threshold. Hereinafter, spot lighting with a narrow lighting range that is implemented when the distance from the host vehicle 1 to the lighting target 2 is greater than the threshold will be referred to as "narrow spot lighting," and spot lighting with a wide lighting range that is implemented when the distance is equal to or less than the threshold will be referred to as "wide spot lighting."

[0018] Here, the diameter (irradiation diameter) of the illumination range of the wide spotlight is 4 m, and the diameter of the illumination range of the narrow spotlight is 2 m (in this specification, unless otherwise specified, the major axis diameter of an ellipse is simply referred to as the diameter. For example, the minor axis diameter is half the length of the major axis diameter). However, the sizes of the illumination ranges of the wide spotlight and the narrow spotlight may be changed depending on the size, type, moving speed, moving direction, etc. of the illuminated object. For example, if the illuminated object is a pedestrian, the size of the wide spotlight may be set to a diameter of two to four times the pedestrian's stride centered on the position of the pedestrian, and the size of the narrow spotlight may be set to a diameter of 1.5 to two times the pedestrian's stride centered on the position of the pedestrian. Furthermore, for example, the sizes of the illumination ranges of the wide spotlight and the narrow spotlight may be increased as the moving speed of the illuminated object increases.

[0019] Although FIG. 2 shows a pedestrian as a representative example of the illumination target 2, the illumination target 2 is not limited to a pedestrian. When the illumination target 2 is a pedestrian, it is preferable that the illumination range of the spotlight avoids the pedestrian's face in order to prevent glare on the pedestrian. Also, in FIG. 2, the narrow spotlight and the illumination range 3 of the narrow spotlight are elliptical in shape, but they may be any shape, such as circular, rectangular, or trapezoidal. Furthermore, the major axis of the elliptical illumination range 3 may be aligned with the movement direction of the illumination target 2. The movement speed and movement direction of the illumination target 2 may be included in the illumination target information, or may be determined by the illumination control unit 12 from the position history of the illumination target.

[0020] The threshold value of the distance from the vehicle 1 to the illumination target 2 for switching between narrow-area spot lighting and wide-area spot lighting is assumed to be approximately 5 to 6 meters. However, the threshold value is not limited to this. The threshold value may change depending on the traveling speed of the vehicle 1. For example, the threshold value may be set larger as the traveling speed of the vehicle 1 decreases.

[0021] Furthermore, frequent switching between narrow-area spotlights and wide-area spotlights can cause the spotlights to flicker. To prevent this, a hysteresis characteristic may be imparted to the control of switching between narrow-area spotlights and wide-area spotlights, as shown in FIG. 3 .

[0022] 4 is a flowchart showing the operation of the spot lighting device 10 according to embodiment 1. The operation of the spot lighting device 10 will be described below with reference to this flowchart.

[0023] When the periphery detection device 22 detects an illumination target, the illumination target information acquisition unit 11 acquires illumination target information from the periphery detection device 22 (step S101).

[0024] The lighting control unit 12 determines whether or not there is a possibility that the lighting target will collide with the host vehicle 1 based on the lighting target information acquired by the lighting target information acquisition unit 11 (step S102). For example, a pedestrian crossing the road on which the host vehicle 1 is traveling, a pedestrian attempting to enter the roadway from the sidewalk, or an obstacle on the roadway is determined to have a possibility of colliding with the host vehicle 1. Furthermore, a pedestrian moving away from the roadway or a stationary object located outside the roadway is determined to have no possibility of colliding with the host vehicle 1. However, even if the stationary object is located outside the roadway, it is determined that there is a possibility of collision if the host vehicle 1 is traveling toward the stationary object.

[0025] If it is determined that there is no possibility of the illumination target colliding with the vehicle 1 (NO in step S102), spot illumination is not performed (step S103), and the process returns to step S101.

[0026] If it is determined that the lighting target may collide with the vehicle 1 (YES in step S102), the lighting control unit 12 determines, based on the lighting target information, whether the distance from the vehicle 1 to the lighting target is less than a predetermined threshold (step S104).

[0027] If the distance from the vehicle 1 to the illumination target is equal to or less than the threshold (YES in step S104), the lighting control unit 12 controls the lighting device 21 to provide wide-area spot lighting toward the illumination target (step S105), and then returns to step S101. On the other hand, if the distance from the vehicle 1 to the illumination target is greater than the threshold (NO in step S104), the lighting control unit 12 controls the lighting device 21 to provide narrow-area spot lighting toward the illumination target (step S106), and then returns to step S101.

[0028] The spotlight device 10 repeatedly executes the above operations.

[0029] The spot lighting device 10 according to the first embodiment performs wide-area spot lighting when the distance from the vehicle 1 to the illumination target 2 is equal to or less than a threshold. Because the illumination range of the wide-area spot lighting is wide, even if the illumination range of the wide-area spot lighting is moved to follow the movement of the illumination target, the driver's perception of flickering is suppressed. This prevents a decrease in visibility of the illumination target.

[0030] Since flickering of spotlight occurs when the illumination range is moved to follow the movement of the illumination target, narrow spotlight may be provided when the illumination target is not moving or is a stationary object even if the distance from the host vehicle 1 to the illumination target 2 is equal to or less than the threshold. Conversely, wide spotlight may be provided at least when the illumination target is moving or is a moving object.

[0031] [Variant 1] If there is a large difference between the illumination range of the wide-area spotlight and the illumination range of the narrow-area spotlight, when the distance between the illumination target and the vehicle 1 changes and the illumination range switches between wide-area spotlight and narrow-area spotlight, the illumination range of the spotlight may change significantly, which may cause the driver to feel uncomfortable.

[0032] In order to suppress this sense of incongruity, when narrow spot lighting is performed (i.e., when the distance from the host vehicle 1 to the illumination target exceeds a threshold), the lighting control unit 12 may gradually widen the illumination range of the narrow spot lighting as the distance from the host vehicle 1 to the illumination target becomes shorter. For example, as shown in Fig. 5 , the area where narrow spot lighting is performed may be divided into multiple areas according to the distance from the host vehicle 1, and as shown in the graph of Fig. 6 , the illumination range of the narrow spot lighting may be widened in multiple stages as the distance from the host vehicle 1 to the illumination target becomes shorter.

[0033] Alternatively, the illumination range of the narrow spotlights may be continuously widened as the distance from the vehicle 1 to the illumination target decreases. In this case, as shown by the solid and dotted lines in the graphs of FIG. 7 , the illumination range of the narrow spotlights immediately before the distance from the vehicle 1 to the illumination target changes from exceeding a threshold to being equal to or less than the threshold may be matched with the illumination range of the wide spotlights immediately after the distance changes to being equal to or less than the threshold. Because the change in the illumination range when switching between the narrow spotlights and the wide spotlights is continuous, the sense of discomfort felt by the driver when switching between the wide spotlights and the narrow spotlights can be further reduced. In particular, if the illumination range is smoothly changed when switching between the wide spotlights and the narrow spotlights, as shown by the dashed line in the graph of FIG. 7 , the sense of discomfort felt by the driver can be minimized.

[0034] Fig. 8 is a flowchart showing the operation of the spot lighting device 10 in this modified example. The flowchart in Fig. 8 is the same as the flowchart in Fig. 4 except that step S201 is added before step S106 in which the lighting control unit 12 performs narrow-area spot lighting. In step S201, the lighting control unit 12 sets the illumination range of the narrow-area spot lighting in accordance with the distance from the vehicle 1 to the illumination target.

[0035] The other steps are the same as those in FIG. 4, and therefore will not be described.

[0036] [Variation 2] If the illumination range of the spotlight is widened, the driver will be able to notice the spotlight more easily, and the driver will be able to quickly recognize the presence of the illuminated target. However, in order to allow the driver to accurately recognize the position of the illuminated target, it is effective to narrow the illumination range of the spotlight and illuminate the illuminated target with pinpoint accuracy. However, as mentioned above, narrowing the illumination range of the spotlight when the distance from the vehicle 1 to the illuminated target is short is not desirable because it causes the driver to feel a flickering sensation.

[0037] Therefore, in this modification, when the distance from the vehicle 1 to the illumination target exceeds a threshold, i.e., when narrow spot illumination is to be implemented, the illumination control unit 12 implements first narrow spot illumination, which has a relatively wide illumination range, at the start of narrow spot illumination, and then, after a certain period of time has elapsed, implements second narrow spot illumination, which has a narrower illumination range than the first narrow spot illumination. The first narrow spot illumination allows the driver to quickly recognize the presence of the illumination target, and the second narrow spot illumination allows the driver to accurately recognize the position of the illumination target. This allows the driver to quickly and accurately recognize the illumination target.

[0038] Here, the diameter of the illumination range of the first narrow-area spotlight is 2 m, and the diameter of the illumination range of the second narrow-area spotlight is 1 m, but the sizes of these illumination ranges may be changed depending on the size, type, moving speed, moving direction, etc. of the illumination target.

[0039] Fig. 9 is a flowchart showing the operation of the spot lighting device 10 in this modified example. The flowchart in Fig. 9 is obtained by replacing step S106 in the flowchart in Fig. 4 with steps S301 to S304. Steps S101 to S105 are the same as those in Fig. 4, so their description will be omitted.

[0040] In this modification, when the distance from the vehicle 1 to the illumination target is greater than the threshold (when the determination in step S104 is NO), the illumination control unit 12 first checks whether the second narrow-area spot illumination is being performed (step S301). If the second narrow-area spot illumination is not being performed (when the determination in step S301 is NO), the illumination control unit 12 performs the first narrow-area spot illumination (step S302).

[0041] The illumination control unit 12 then checks whether a certain time has elapsed since the start of narrow spot illumination (here, first narrow spot illumination) (step S303). If the certain time has not elapsed since the start of narrow spot illumination (NO in step S303), the process returns to step S101. If the certain time has elapsed since the start of narrow spot illumination (YES in step S303), the illumination control unit 12 performs second narrow spot illumination (step S304), and then returns to step S101.

[0042] After the second narrow-area spotlighting is started, the determination in step S301 is YES, and the process proceeds from step S301 to step S304, so that the second narrow-area spotlighting continues.

[0043] The switching from the first narrow-band spotlight to the second narrow-band spotlight may be performed instantly, or may be performed gradually over a period of time so as not to cause discomfort to the driver.

[0044] [Variation 3] It is known that bluish light appears brighter in dimly lit environments. Therefore, if spotlighting is performed using bluish light, it is expected that the driver will be more likely to notice the spotlight. In addition, it is known that warm-colored light (reddish or yellowish) provides high visibility. Therefore, if spotlighting is performed using warm-colored light, it is expected that the driver will be more likely to recognize the illuminated object.

[0045] Therefore, in this modification, when the distance from the vehicle 1 to the illumination target exceeds a threshold, i.e., when narrow spot illumination is to be performed, the illumination control unit 12 performs narrow spot illumination with bluish light when narrow spot illumination begins, and then performs narrow spot illumination with warm light after a certain period of time has elapsed. Narrow spot illumination with bluish light allows the driver to quickly recognize the presence of the illumination target, and narrow spot illumination with warm light enhances the driver's recognition of the illumination target. This allows the driver to quickly and accurately recognize the illumination target.

[0046] Fig. 10 is a flowchart showing the operation of the spot lighting device 10 in this modified example. The flowchart in Fig. 10 is obtained by replacing step S106 in the flowchart in Fig. 4 with steps S401 to S404. Steps S101 to S105 are the same as those in Fig. 4, and therefore their explanation will be omitted.

[0047] In this modification, when the distance from the vehicle 1 to the illumination target is greater than the threshold (when the determination in step S104 is NO), the illumination control unit 12 first checks whether narrow-band spot illumination is being performed with warm-colored light (step S401). If narrow-band spot illumination with warm-colored light is not being performed (when the determination in step S401 is NO), the illumination control unit 12 performs narrow-band spot illumination with bluish light (step S402).

[0048] The illumination control unit 12 then checks whether a certain time has elapsed since the start of narrow spotlighting (step S403). If the certain time has not elapsed since the start of narrow spotlighting (NO in step S403), the process returns to step S101. If the certain time has elapsed since the start of narrow spotlighting (YES in step S403), the illumination control unit 12 performs narrow spotlighting with warm-colored light (step S404), and then returns to step S101.

[0049] After the narrow-area spotlighting with warm-colored light has started, a YES determination is made in step S401, and the process proceeds from step S401 to step S404, so that the narrow-area spotlighting with warm-colored light continues.

[0050] [Variation 4] This variation combines Variations 2 and 3. That is, in a state where the distance from the vehicle 1 to the illumination target exceeds a threshold, i.e., in a state where narrow spot illumination is to be performed, the illumination control unit 12 performs first narrow spot illumination with bluish light when narrow spot illumination begins, and then performs second narrow spot illumination with warm light after a certain period of time has elapsed. The first narrow spot illumination with bluish light allows the driver to quickly recognize the presence of the illumination target, and the second narrow spot illumination with warm light allows the driver to accurately recognize the position of the illumination target. This allows the driver to quickly and accurately recognize the illumination target.

[0051] Fig. 11 is a flowchart showing the operation of the spot lighting device 10 in this modified example. The flowchart in Fig. 11 is obtained by replacing step S106 in the flowchart in Fig. 4 with steps S501 to S504. Steps S101 to S105 are the same as those in Fig. 4, and therefore their explanation will be omitted.

[0052] In this modification, when the distance from the vehicle 1 to the illumination target is greater than the threshold (when the determination in step S104 is NO), the illumination control unit 12 first checks whether the second narrow-band spot illumination is being performed (step S501). If the second narrow-band spot illumination is not being performed (when the determination in step S501 is NO), the illumination control unit 12 performs the first narrow-band spot illumination with blue light (step S502).

[0053] The illumination control unit 12 then checks whether a certain time has elapsed since the start of narrow-area spotlighting (here, first narrow-area spotlighting) (step S503). If the certain time has not elapsed since the start of narrow-area spotlighting (NO in step S503), the process returns to step S101. If the certain time has elapsed since the start of narrow-area spotlighting (YES in step S503), the illumination control unit 12 performs second narrow-area spotlighting with warm-colored light (step S504), and then returns to step S101.

[0054] After the second narrow-area spotlighting with warm-colored light is started, a YES determination is made in step S501, and the process proceeds from step S501 to step S504, so that the narrow-area spotlighting with warm-colored light continues.

[0055] [Variation 5] In Variation 4, the switching from the first narrow-band spotlight to the second narrow-band spotlight and the switching from bluish light to warm-colored light are performed simultaneously, but a time lag may be provided between the two.

[0056] For example, Fig. 12 is a flowchart showing a case where the first narrow-band spotlight is switched to the second narrow-band spotlight, and then the bluish light is switched to the warm-colored light. In the flowchart of Fig. 12, step S106 in the flowchart of Fig. 4 is replaced with steps S601 to S607.

[0057] 12, when the distance from the vehicle 1 to the illumination target is greater than the threshold (when the determination in step S104 is NO), the illumination control unit 12 first checks whether the second narrow-band spot illumination is being performed (step S601). If the second narrow-band spot illumination is not being performed (when the determination in step S601 is NO), the illumination control unit 12 performs the first narrow-band spot illumination with bluish light (step S602).

[0058] Then, the illumination control unit 12 checks whether a certain time has elapsed since the start of narrow spot illumination (here, first narrow spot illumination) (step S603). If the certain time has not elapsed since the start of narrow spot illumination (NO in step S603), the process returns to step S101. If the certain time has elapsed since the start of narrow spot illumination (YES in step S603), the illumination control unit 12 performs second narrow spot illumination while maintaining bluish light (step S604).

[0059] Next, the illumination control unit 12 checks whether a certain time has elapsed since the start of the second narrow-band spotlight (step S605). If the certain time has not elapsed since the start of the second narrow-band spotlight (NO in step S605), the illumination control unit 12 continues the second narrow-band spotlight with blue light (step S606) and returns to step S101. If the certain time has elapsed since the start of the second narrow-band spotlight (YES in step S605), the illumination control unit 12 performs the second narrow-band spotlight with warm light (step S607) and returns to step S101.

[0060] After the second narrow-area spotlighting with warm-colored light is started, the result of step S601 is determined to be YES, and the result of step S605 is also determined to be YES, so that the second narrow-area spotlighting with warm-colored light continues.

[0061] 13 is a flowchart showing a case where the first narrow-band spotlight is switched to the second narrow-band spotlight first, and then the bluish light is switched to the warm-colored light after that. The flowchart in FIG. 13 is obtained by replacing step S106 in the flowchart in FIG. 4 with steps S701 to S707.

[0062] 13 , when the distance from the vehicle 1 to the illumination target is greater than the threshold (when the determination in step S104 is NO), the illumination control unit 12 first checks whether the narrow-band spot illumination is being performed with warm-colored light (step S701). If the narrow-band spot illumination is not being performed with warm-colored light (when the determination in step S701 is NO), the illumination control unit 12 performs the first narrow-band spot illumination with bluish light (step S702).

[0063] The illumination control unit 12 then checks whether a certain time has elapsed since the start of narrow spotlighting (here, first narrow spotlighting) (step S703). If the certain time has not elapsed since the start of narrow spotlighting (NO in step S703), the process returns to step S101. If the certain time has elapsed since the start of narrow spotlighting (YES in step S703), the illumination control unit 12 performs the first narrow spotlighting with warm light (step S704).

[0064] Next, the illumination control unit 12 checks whether a certain time has elapsed since the start of spot illumination with warm-colored light (here, second narrow-area spot illumination) (step S705). If the certain time has not elapsed since the start of spot illumination with warm-colored light (NO in step S705), the illumination control unit 12 continues the first narrow-area spot illumination with warm-colored light (step S706) and returns to step S101. If the certain time has elapsed since the start of spot illumination with warm-colored light (YES in step S705), the illumination control unit 12 performs the second narrow-area spot illumination with warm-colored light (step S707) and returns to step S101.

[0065] After the second narrow-area spotlighting with warm-colored light is started, a YES determination is made in step S701 and a YES determination is made in step S705, so that the second narrow-area spotlighting with warm-colored light continues.

[0066] [Variation 6] In Variation 2, the condition for switching from the start of the first narrow-band spotlighting to the second narrow-band spotlighting is that a certain time has elapsed since the start of the first narrow-band spotlighting. Furthermore, in Variation 3, the condition for switching from the start of the narrow-band spotlighting with bluish light to the spotlighting with warm-colored light is that a certain time has elapsed since the start of the narrow-band spotlighting with bluish light. This certain time is assumed to be the time required for the driver to recognize the presence of an illuminated target.

[0067] Therefore, in this modified example, the spot lighting device 10 determines whether the driver has actually recognized the presence of the illumination target, and if it is determined that the driver has recognized the presence of the illumination target, switches from the first narrow-band spot lighting to the second narrow-band spot lighting, or switches from blue light to warm-colored light.

[0068] Fig. 14 is a block diagram showing the configuration of a spot lighting system according to this modification. The configuration of the spot lighting system in Fig. 14 is obtained by adding a driver monitoring system (DMS) 23 connected to the spot lighting device 10 and by adding a driver information acquisition unit 13 within the spot lighting device 10 to the configuration in Fig. 1.

[0069] The DMS 23 monitors the state of the driver of the vehicle 1. The driver information acquisition unit 13 acquires from the DMS 23 at least information relating to the driver's line of sight (for example, the direction of the line of sight, the direction of the face, etc.).

[0070] In this embodiment, the lighting control unit 12 determines the position at which the driver is gazing (hereinafter referred to as the "gaze position") based on information acquired by the driver information acquisition unit 13 from the DMS 23, and determines whether the driver's gaze position is within a predetermined range that includes the illumination target. When the driver's gaze position is within the illumination range of the spotlight, the lighting control unit 12 determines that the driver has recognized the illumination target, and switches from the first narrow-band spotlight to the second narrow-band spotlight, or switches from bluish light to warm-colored light.

[0071] According to this modified example, the first narrow spotlight or narrow spotlight with blue light, which is easy for the driver to notice, is continuously provided until it is determined that the driver has recognized the illuminated object, thereby more reliably allowing the driver to recognize the illuminated object.

[0072] In addition, in the flowchart of the operation of the spot lighting device 10 according to this modified example, the determination of "Has a certain amount of time elapsed since the start of narrow-area spot lighting?" in step S303 of FIG. 9, step S403 of FIG. 10, step S503 of FIG. 11, step S603 of FIG. 12, and step S703 of FIG. 13 is replaced with a determination of "Is the driver's gaze position within the illumination range of the narrow-area spot lighting?"

[0073] <Embodiment 2> In embodiment 2, the lighting control unit 12 of the spot lighting device 10 detects the movement direction of the lighting target based on information related to the position of the lighting target, and when the lighting target is moving, the lighting range of the spot lighting (narrow spot lighting and wide spot lighting) is expanded toward the movement direction of the lighting target compared to when the lighting target is not moving.

[0074] 15 compares the illumination range 3 of the spotlight when the illumination target 2 is stationary with the illumination range 3 of the spotlight when the illumination target 2 is moving. As shown in FIG. 15, when the illumination target 2 (pedestrian) is moving to the right, the illumination range 3 of the spotlight is expanded to the right. The direction of movement of the illumination target may be included in the illumination target information acquired from the periphery detection device 22, or may be determined by the illumination control unit 12 from the position history of the illumination target. It is preferable that the expansion width of the illumination range be equal to or greater than the amount of movement of the illumination target.

[0075] Fig. 16 is a flowchart showing the operation of spot lighting device 10 according to embodiment 2. In the flowchart of Fig. 16, steps S105 and S106 of the flowchart of Fig. 4 are replaced with steps S801 and S802, respectively.

[0076] Step S801 is performed when the distance from the vehicle 1 to the illumination target is equal to or less than a threshold value (when a determination of YES is made in step S104). In step S801, the illumination control unit 12 performs wide-area spot illumination with an illumination range expanded in the direction of movement of the illumination target. That is, in step S801, wide-area spot illumination is performed toward the illumination target, and if the illumination target is moving at that time, the illumination range of the wide-area spot illumination is expanded in the direction of movement. Note that if the illumination target is not moving, wide-area spot illumination similar to that in embodiment 1 may be performed.

[0077] Step S802 is performed when the distance from the vehicle 1 to the illumination target exceeds a threshold (when step S104 is determined as NO). In step S802, the illumination control unit 12 performs narrow spot illumination with an expanded illumination range in the direction of movement of the illumination target. That is, in step S802, narrow spot illumination is performed toward the illumination target, and if the illumination target is moving at that time, the illumination range of the narrow spot illumination is expanded in the direction of movement. If the illumination target is not moving, narrow spot illumination similar to that in embodiment 1 may be performed.

[0078] According to the spot lighting device 10 of embodiment 2, the illumination range of the spot lighting is expanded in the direction of movement of the illuminated object, so that even if the illuminated object moves, it is less likely to leave the illumination range of the spot lighting, making it easier for the driver of the vehicle 1 to follow the moving illuminated object with his or her eyes.

[0079] Third Embodiment In spot lighting, it is necessary to move the illumination range of the spot lighting so as to follow the movement of the illumination target. In the third embodiment, the illumination control unit 12 slows down the movement speed of the end portion of the illumination range of the spot lighting (narrow spot lighting and wide spot lighting) on ​​the opposite side of the movement direction compared to the movement speed of the end portion on the movement direction side.

[0080] Fig. 17 shows how the illumination range 3 of the spotlight changes as the illumination target 2 moves. When the illumination target 2 moves to the right as shown in Fig. 17, the right end of the illumination range 3 of the spotlight expands to the right at the same speed as the illumination target 2, but the left end of the illumination range 3 of the spotlight gradually shrinks at a slower speed than the illumination target 2. As a result, the illumination range 3 of the spotlight extends in the left-right direction, but its left end becomes dark. In other words, as shown in the graph in Fig. 17, the brightness of the illumination range 3 of the spotlight trails off in the opposite direction to the movement of the illumination target 2.

[0081] Fig. 18 is a flowchart showing the operation of spot lighting device 10 according to embodiment 3. The flowchart in Fig. 18 is obtained by adding steps S801a and S802b after steps S801 and S802, respectively, in the flowchart in Fig. 16.

[0082] In step S801a, the illumination control unit 12 gradually reduces (gradually darkens) the illumination range of the wide spotlight applied in step S801 on the opposite side of the movement direction of the illumination target. In step S801b, the illumination control unit 12 gradually reduces (gradually darkens) the illumination range of the narrow spotlight applied in step S802 on the opposite side of the movement direction of the illumination target.

[0083] That is, in this embodiment, after wide-area spotlighting with an expanded illumination range in the direction of movement of the illumination target is performed in step S801, the end of the illumination range on the opposite side to the direction of movement of the illumination target is gradually reduced in step S801a, so that the brightness of the illumination range of the wide-area spotlight is reduced to a tail on the opposite side to the direction of movement of the illumination target.

[0084] Similarly, after narrow spotlighting with an expanded illumination range in the direction of movement of the illumination target is performed in step S802, the end of the illumination range on the opposite side to the direction of movement of the illumination target is gradually reduced in step S802a, causing the brightness of the illumination range of the narrow spotlight to trail on the opposite side to the direction of movement of the illumination target.

[0085] According to the spot lighting device 10 of embodiment 3, the brightness of the illumination range of the spot lighting leaves a trail on the opposite side of the direction of movement of the illuminated object, making it easier for the driver of the vehicle 1 to follow the moving illuminated object with his or her eyes.

[0086] <Embodiment 4> In embodiment 4, the lighting control unit 12 changes the lighting mode (e.g., brightness, hue, flashing cycle, etc.) of spot lighting (narrow spot lighting and wide spot lighting) depending on the degree of danger to the vehicle 1 of the illuminated object.

[0087] Fig. 19 is a block diagram showing the configuration of a spot lighting system according to this modification. The configuration of the spot lighting system in Fig. 19 is different from the configuration in Fig. 14 in that a vehicle state detection device 24 connected to the spot lighting device 10 is added, and a risk calculation unit 14 is added within the spot lighting device 10.

[0088] The vehicle state detection device 24 detects information about the driving state of the host vehicle 1, such as the driving speed, acceleration, steering angle, and whether or not the brakes are being operated, of the host vehicle 1. The vehicle state detection device 24 may be a sensor that detects the state of the host vehicle 1, or an ECU (Electronic Control Unit) that collects information detected by the sensor and controls the driving of the host vehicle 1.

[0089] The risk calculation unit 14 calculates the risk of the illuminated target to the host vehicle 1 based on the illumination target information acquired by the illumination target information acquisition unit 11 and the state of the host vehicle 1 detected by the vehicle state detection device 24. For example, if the illumination target is a pedestrian, a pedestrian crossing the road ahead of the host vehicle 1 or a pedestrian attempting to enter the roadway from the sidewalk is likely to collide with the host vehicle 1 and is therefore judged to be at high risk. The risk calculation also takes into account the traveling speed of the host vehicle 1 and the position of the illuminated target, and the shorter the time until the host vehicle 1 collides with the illuminated target and the higher the likelihood of a collision, the higher the risk of the illuminated target.

[0090] The lighting control unit 12 sets the lighting mode of the spotlight in accordance with the danger level of the lighting target calculated by the danger level calculation unit 14. Specifically, when the danger level of the lighting target is high, the lighting control unit 12 sets the lighting mode of the spotlight to be more conspicuous (i.e., more noticeable) than when the danger level of the lighting target is low.

[0091] Highly conspicuous spotlights include reddish light spotlights and flashing spotlights, but any type that catches the driver's eye may be used.

[0092] According to the spot lighting device 10 of the fourth embodiment, highly conspicuous spot lighting is performed on the illumination target with a high degree of danger, so that the driver can be made aware of the illumination target with a high degree of danger early on.

[0093] Fifth Embodiment In the first to fourth embodiments, examples have been shown in which individual spot lighting is performed on each illumination target. In the fifth embodiment, when an assembly of multiple illumination targets is detected by the illumination target information acquisition unit 11, the illumination control unit 12 regards the assembly as a single illumination target and performs spot lighting on the assembly collectively.

[0094] For example, as shown in Fig. 20 , when the periphery detection device 22 detects a state in which three pedestrians 2a, 2b, and 2c, which are illumination targets 2, are walking in a group, the illumination control unit 12 regards the group, i.e., the collection of pedestrians 2a, 2b, and 2c, as a single illumination target, sets a single illumination range 3 for the group, and performs collective spot lighting. In this case, the size and shape of the illumination range 3 of the spot lighting are set so that the entire group (all pedestrians 2a, 2b, and 2c) is illuminated. In Fig. 20 , the pedestrians 2a, 2b, and 2c are lined up horizontally as seen from the host vehicle 1, so the illumination range 3 of the spot lighting is set to a horizontally elongated shape. However, if the pedestrians 2a, 2b, and 2c are lined up vertically, the illumination range 3 of the spot lighting may be set to a vertically elongated shape.

[0095] When applying this embodiment to the fourth embodiment, the risk calculation unit 14 may calculate the risk level of an entire group of illumination targets, or may calculate the risk level of each individual illumination target included in the group. In particular, when the illumination range of the spotlight is set to be wide (e.g., a diameter of 4 m or more), the risk calculation unit 14 may calculate the risk level of each individual illumination target included in the group, and the illumination control unit 12 may perform collective spotlighting while illuminating a portion of the illumination range where illumination targets with a high risk level are located with a higher degree of conspicuous illumination than a portion where illumination targets with a low risk level are located. For example, in the example of FIG. 20 , if a group of pedestrians 2a, 2b, and 2c, which are illumination targets 2, are walking toward the roadway, the leading pedestrian 2a is closest to the roadway and therefore has a high risk level. In this case, as shown in FIG. 21 , the portion of the illumination range 3 of the spotlight where the pedestrian 2a is located is illuminated with a high degree of conspicuous illumination.

[0096] <Hardware Configuration Example> FIGS. 22 and 23 are diagrams illustrating an example of the hardware configuration of the spot lighting device 10. The functions of the components of the spot lighting device 10 illustrated in FIGS. 1, 14, or 19 are realized, for example, by a processing circuit 50 illustrated in FIG. 22. That is, the spot lighting device 10 includes a processing circuit 50 that provides spot lighting toward an illumination target located at least closer to the host vehicle 1 than the illumination distance of the host vehicle's passing lights, acquires information related to the position of the illumination target, and, when the illumination target is moving and the distance from the host vehicle 1 to the illumination target is equal to or less than a predetermined threshold, widens the illumination range of the spot lighting toward the illumination target compared to when the distance exceeds the threshold. The processing circuit 50 may be dedicated hardware, or may be configured using a processor (also referred to as a central processing unit (CPU), processing device, arithmetic device, microprocessor, microcomputer, or DSP (Digital Signal Processor)) that executes a program stored in a memory.

[0097] When the processing circuitry 50 is dedicated hardware, the processing circuitry 50 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. The functions of the components of the spot lighting device 10 may be realized by individual processing circuits, or these functions may be collectively realized by a single processing circuit.

[0098] FIG. 23 shows an example of the hardware configuration of the spot lighting device 10 when the processing circuit 50 is configured using a processor 51 that executes a program. In this case, the functions of the components of the spot lighting device 10 are realized by software, etc. (software, firmware, or a combination of software and firmware). The software, etc. is written as a program and stored in the memory 52. ​​The processor 51 realizes the functions of each part by reading and executing the program stored in the memory 52. ​​That is, the spot lighting device 10 includes the memory 52 for storing a program that, when executed by the processor 51, results in the following: providing spot lighting to an illumination target located at least closer to the vehicle 1 than the illumination distance of the vehicle's passing lights; acquiring information related to the position of the illumination target; and widening the illumination range of the spot lighting on the illumination target when the illumination target is moving and the distance from the vehicle 1 to the illumination target is equal to or less than a predetermined threshold value compared to when the distance exceeds the threshold value. In other words, the program causes a computer to execute the procedures and methods of the operation of the components of the spot lighting device 10.

[0099] Here, the memory 52 may be, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read Only Memory), a HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), and a drive device for such a disk, or any other storage medium that will be used in the future.

[0100] The above describes a configuration in which the functions of the components of the spot lighting device 10 are realized either by hardware or software, etc. However, the present invention is not limited to this configuration, and the spot lighting device 10 may be configured such that some of the components are realized by dedicated hardware and other components are realized by software, etc. For example, the functions of some of the components may be realized by the processing circuit 50 as dedicated hardware, and the functions of other components may be realized by the processing circuit 50 as the processor 51 reading and executing a program stored in the memory 52.

[0101] As described above, the spotlight device 10 can realize the above-described functions by hardware, software, or a combination of these.

[0102] It is possible to freely combine the embodiments, and to modify or omit the embodiments as appropriate.

[0103] The above description is illustrative in all respects, and it is understood that countless variations not illustrated can be envisioned.

[0104] REFERENCE SIGNS LIST 1 Vehicle, 2 Illumination target, 3 Spot lighting range, 10 Spot lighting device, 11 Illumination target information acquisition unit, 12 Illumination control unit, 13 Driver information acquisition unit, 14 Risk calculation unit, 21 Lighting device, 22 Surroundings detection device, 23 DMS, 24 Vehicle state detection device

Claims

1. A spot lighting device that provides spot lighting toward an illumination target that is located at least closer to the vehicle than the lighting distance of the vehicle's passing lights, the spot lighting device comprising: an illumination target information acquisition unit that acquires information related to the position of the illumination target; and an illumination control unit that widens the illumination range of the spot lighting for the illumination target when the illumination target is moving and the distance from the vehicle to the illumination target is equal to or less than a predetermined threshold value, compared to when the distance exceeds the threshold value.

2. The spot lighting device according to claim 1, wherein, when the distance from the vehicle to the lighting target exceeds the threshold, the lighting control unit starts the spot lighting on the lighting target and then narrows the lighting range of the spot lighting when a specific condition is satisfied.

3. The spot lighting device of claim 2, wherein, when the distance from the vehicle to the lighting target exceeds the threshold, the lighting control unit starts the spot lighting on the lighting target with bluish light, and when a certain time has elapsed since narrowing the lighting range of the spot lighting, changes the color of the light of the spot lighting to a warm color.

4. The spot lighting device according to claim 2, further comprising a driver information acquisition unit that acquires information related to the driver's line of sight, wherein the specific condition is that the driver's gaze position is within the lighting range of the spot lighting.

5. The spot lighting device of claim 1, wherein, when the distance from the vehicle to the lighting target exceeds the threshold, the lighting control unit starts the spot lighting on the lighting target with bluish light, and when a specific condition is satisfied, changes the color of the spot lighting light to a warm color.

6. The spot lighting device according to claim 5, wherein, when the distance from the vehicle to the lighting target exceeds the threshold, the lighting control unit narrows the lighting range of the spot lighting after a certain time has elapsed since changing the color of the light of the spot lighting to a warm color.

7. The spot lighting device according to claim 5, further comprising a driver information acquisition unit that acquires information related to the driver's line of sight, wherein the specific condition is that the driver's gaze position is within the lighting range of the spot lighting.

8. The spot lighting device of claim 1, wherein, when the distance from the vehicle to the lighting target exceeds the threshold value, the lighting control unit starts the spot lighting on the lighting target with bluish light, and when a specific condition is satisfied, changes the color of the light of the spot lighting to a warm color and narrows the lighting range of the spot lighting.

9. The spot lighting device according to claim 8, further comprising a driver information acquisition unit that acquires information related to the driver's line of sight, wherein the specific condition is that the driver's gaze position is within the lighting range of the spot lighting.

10. The spot lighting device of claim 1, wherein, when the distance from the vehicle to the lighting target exceeds the threshold, the lighting control unit gradually widens the lighting range of the spot lighting as the distance from the vehicle to the lighting target becomes shorter.

11. The spot lighting device of claim 10, wherein the lighting control unit matches the lighting range of the spot lighting immediately before the distance from the vehicle to the lighting target changes from exceeding the threshold to being below the threshold, with the lighting range of the spot lighting immediately after the distance changes to being below the threshold.

12. The spot lighting device according to claim 1, wherein the lighting control unit expands the lighting range of the spot lighting in the direction of movement of the lighting target when the lighting target is moving compared to when the lighting target is not moving.

13. The spot lighting device of claim 1, wherein when the lighting range of the spot lighting is moved to follow the movement of the lighting target, the lighting control unit slows down the movement speed of the end of the lighting range of the spot lighting on the opposite side of the movement direction compared to the movement speed of the end of the lighting range on the movement direction side.

14. The spot lighting device of claim 1, wherein the lighting control unit further includes a risk calculation unit that calculates a risk level of the illuminated object to the vehicle, and the lighting control unit performs the spot lighting of the illuminated object in a manner that is more conspicuous when the risk level is high compared to when the risk level is low.

15. The spot lighting device of claim 14, wherein when a collection of a plurality of the illumination targets is detected, the lighting control unit applies the spot lighting to the collection of the plurality of the illumination targets collectively, and illuminates in a manner that is more conspicuous in a portion of the illumination range of the spot lighting where the illumination targets having a high level of danger are located compared to a portion where the illumination targets having a low level of danger are located.

16. A spot lighting method, comprising: a spot lighting device providing spot lighting toward an illumination target located at least closer to the vehicle than the illumination distance of the vehicle's passing lights; an illumination target information acquisition unit of the spot lighting device acquiring information relating to the position of the illumination target; and, when the illumination target is moving and the distance from the vehicle to the illumination target is equal to or less than a predetermined threshold, a lighting control unit of the spot lighting device widening the illumination range of the spot lighting for the illumination target compared to when the distance exceeds the threshold.

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