Patent Publication Number: US-2023142677-A1

Title: Vehicle headlight

Description:
TECHNICAL FIELD 
     The present invention relates to a vehicle headlight. 
     BACKGROUND ART 
     Conventionally, a vehicle headlight that changes a light distribution pattern of emitted light on the basis of information from a detection device that detects another vehicle located in front of a vehicle is known. Patent Literature 1 and Patent Literature 2 below describe such vehicle headlights. 
     A vehicle headlight described in Patent Literature 1 below includes a lamp unit having a plurality of LEDs (Light Emitting Diodes) capable of individually changing the amount of light emitted, and a control unit, and irradiation spots irradiated with the light from the respective LEDs are arranged in a horizontal direction. The control unit controls the lamp unit to turn off the LED corresponding to the irradiation spot overlapping with another vehicle based on information from a detection device that detects another vehicle located in front of the host vehicle. With such a configuration, it is possible to suppress dazzling of an occupant of the other vehicle. 
     A vehicle headlight described in Patent Literature 2 below includes a lamp unit including a plurality of LEDs (Light Emitting Diodes) capable of individually changing the amount of light emitted. The vehicle headlight can be switched from a first state in which light having a predetermined light distribution pattern is emitted to a second state in which light having a light distribution pattern in which a light shielding region that is not irradiated with the light from the lamp unit in the predetermined light distribution pattern is formed is emitted. The vehicle headlight is configured such that another vehicle located in front of the vehicle and the light shielding region overlap with each other, thereby suppressing dazzling of an occupant of the other vehicle.
     Patent Literature 1: JP 2015-16773 A   Patent Literature 2: JP 2015-015104 A   

     SUMMARY OF THE INVENTION 
     A vehicle headlight according to a first aspect of the present invention includes: a first lamp unit including a plurality of first light emitting units capable of individually changing an amount of light emitted, the first lamp unit emitting light from the plurality of first light emitting units such that first irradiation spots irradiated with the light from the respective first light emitting units are arranged at least in a horizontal direction; a second lamp unit including a plurality of second light emitting units capable of individually changing an amount of light emitted, the second lamp unit emitting light from the plurality of second light emitting units such that second irradiation spots irradiated with the light from the respective second light emitting units are arranged in a matrix; a region determination unit that determines, based on a signal indicating a state of another vehicle from a detection device that detects the other vehicle located in front of the vehicle, a predetermined region overlapping with a visual recognition portion for allowing a driver of the other vehicle to visually recognize the outside of the vehicle; and a control unit, wherein the second irradiation spots are smaller than the first irradiation spots, and at least one of the first irradiation spots overlaps with at least one of the second irradiation spots, when the predetermined region is not determined by the region determination unit, the control unit controls the first lamp unit such that at least light is emitted from the first lamp unit, and when the predetermined region is determined by the region determination unit, the control unit controls the first lamp unit such that an amount of light emitted from the first light emitting unit corresponding to the first irradiation spot overlapping with the predetermined region is reduced, and controls the second lamp unit such that an amount of light emitted from the second light emitting unit corresponding to the second irradiation spot overlapping with the predetermined region is reduced or becomes zero, and light is emitted from the second light emitting unit corresponding to the second irradiation spot overlapping with the predetermined region and not overlapping with the predetermined region. 
     Here, examples of the visual recognition portion for the driver of the other vehicle to visually recognize the outside of the vehicle include a front window in a case where the other vehicle is an oncoming vehicle, and include a side mirror, a rear-view mirror, an imaging device that images the rear of the vehicle, and the like in a case where the other vehicle is a preceding vehicle. In addition, the fact that the amount of light becomes zero includes that the amount of light is reduced to zero and the amount of light is maintained at zero. 
     In the vehicle headlight of the first aspect, the amount of the light emitted from the first lamp unit and irradiated on the visual recognition portion of the other vehicle is reduced or becomes zero, and the amount of the light emitted from the second lamp unit and irradiated on the visual recognition portion of the other vehicle is reduced or becomes zero. Therefore, according to the vehicle headlight of the first aspect, it is possible to suppress dazzling of an occupant of the other vehicle. Further, in the vehicle headlight of the first aspect, the second irradiation spot overlapping with the first irradiation spot in which the amount of the emitted light is reduced and not overlapping with the predetermined region is irradiated with light. Therefore, the light from the second lamp unit can be irradiated to at least a portion of a region not overlapping with the predetermined region in the first irradiation spot in which the amount of the emitted light is reduced. Therefore, according to the vehicle headlight of the first aspect, the forward visibility can be improved as compared with a case where the second lamp unit is not provided. 
     In the vehicle headlight according to the first aspect, when the predetermined region is determined by the region determination unit, the control unit may control the second lamp unit so that the amount of light emitted from the second light emitting unit corresponding to the second irradiation spot overlapping with the first irradiation spot overlapping with the predetermined region and not overlapping with the predetermined region increases as compared with a case where the predetermined region is not determined by the region determination unit. 
     With such a configuration, as compared with the case where the amount of the light does not increase, the amount of the light from the second lamp unit irradiated to at least a portion of the region not overlapping with the predetermined region in the first irradiation spot in which the amount of the emitted light is reduced can be increased, and the forward visibility can be further improved. 
     In the vehicle headlight according to the first aspect, at least one of the first irradiation spots may overlap with at least two of the second irradiation spots, and when the predetermined region is determined by the region determination unit, the control unit may control the second lamp unit such that the second light emitting unit corresponding to the second irradiation spot closer to the predetermined region among the second irradiation spots overlapping with the first irradiation spot overlapping with the predetermined region and not overlapping with the predetermined region emits a larger amount of light. 
     For example, in the case that a portion of the first irradiation spot in which the amount of the emitted light is reduced and a portion of the other first irradiation spot adjacent to the first irradiation spot overlap with each other, the overlapping region overlapping with the other first irradiation spot in the first irradiation spot in which the amount of the emitted light is reduced is irradiated with the light from the first light emitting unit corresponding to the other first irradiation spot. Here, in the irradiation spot irradiated with light, the intensity of light irradiated from the center side toward the outer edge side tends to decrease. Therefore, the intensity of the light from the first light emitting unit corresponding to another first irradiation spot irradiated to the overlapping region tends to increase toward the predetermined region. In this vehicle headlight, a second irradiation spot closer to a predetermined region among second irradiation spots overlapping with the first irradiation spot in which the amount of the emitted light is reduced and not overlapping with the predetermined region has a higher intensity of the emitted light. For this reason, for example, in a case where the second irradiation spot overlapping with the first irradiation spot in which the amount of the emitted light is reduced and not overlapping with the predetermined region overlaps with the overlapping region, the light intensity in the overlapping region can be made uniform, and the driver can be prevented from feeling uncomfortable about the overlapping region. 
     Alternatively, when the predetermined region is determined by the region determination unit, the control unit may control the second lamp unit such that the amount of light emitted from the second light emitting unit corresponding to the second irradiation spot overlapping with the first irradiation spot overlapping with the predetermined region and not overlapping with the predetermined region does not change from the amount of light when the predetermined region is not determined by the region determination unit. 
     With such a configuration, the control of the second lamp unit by the control unit can be simplified as compared with the case where the amount of the light changes. 
     In the vehicle headlight according to the first aspect, when the predetermined region is not determined by the region determination unit, the control unit may control the first lamp unit and the second lamp unit so that light is emitted from the first lamp unit and the second lamp unit. 
     With such a configuration, in a case where the predetermined region is not determined by the region determination unit, the light distribution pattern is formed by the light including light emitted from the first lamp unit and the light emitted from the second lamp unit. As described above, since at least one first irradiation spot overlaps with at least one second irradiation spot, the region irradiated with the light emitted from the first lamp unit and the region irradiated with the light emitted from the second lamp unit can overlap with each other. Therefore, according to the vehicle headlight of the first aspect, the degree of freedom of the light intensity distribution in the formed light distribution pattern can be improved as compared with the case where the light from the second lamp unit is not emitted in the above case. 
     A vehicle headlight according to a second aspect of the present invention includes: a lamp unit including a plurality of light emitting units capable of individually changing an amount of light emitted and arranged in a matrix, the lamp unit emitting light having a light distribution pattern corresponding to the amount of light emitted from the plurality of light emitting units, wherein the lamp unit can be switched between a first state in which light of a predetermined light distribution pattern is emitted and a second state in which light of a light distribution pattern in which a light amount of a predetermined region in the predetermined light distribution pattern is reduced is emitted, and when the state is switched from the second state to the first state, the light amount in a partial region of the predetermined region is returned to the light amount in the partial region in the first state, and the partial region expands over time. 
     In the vehicle headlight of the second aspect, when the predetermined region overlaps with the visual recognition portion for the driver of another vehicle to visually recognize the outside of the vehicle, switching from the first state to the second state can suppress dazzling of the occupant of the other vehicle. In addition, in the vehicle headlight of the second aspect, it is brightened from a partial region in a predetermined region, and the bright region expands over time. In other words, the region in which the light amount is reduced decreases over time. Therefore, according to the vehicle headlight of the second aspect, it is possible to suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region as compared with the case of instantaneously switching from the second state to the first state. 
     In the vehicle headlight according to the second aspect, the partial region may expand upward from a lower edge of the predetermined region over time. 
     The object to which the driver pays attention includes, for example, a pedestrian, an obstacle, and the like on a road as well as other vehicles. In this vehicle headlight, when the state is switched from the second state to the first state, it can be brightened from the side close to the road in the predetermined region. Therefore, according to the vehicle headlight of the second aspect, for example, in a case where the predetermined region overlaps with a pedestrian, an obstacle, or the like on the road when the state is switched from the second state to the first state, the pedestrian, the obstacle, or the like can be recognized by the driver more quickly. 
     In the vehicle headlight according to the second aspect, the partial region may expand downward from an upper edge of the predetermined region over time. 
     Signs are located above the road. In this vehicle headlight of the second aspect, when the state is switched from the second state to the first state, it is brightened from the upper side in the predetermined region. Therefore, according to the vehicle headlight of the second aspect, for example, when the predetermined region and a sign overlap with each other at the time of switching from the second state to the first state, the sign can be recognized by the driver more quickly. 
     In the vehicle headlight according to the second aspect, the partial region may expand from an edge on one side in a horizontal direction of the predetermined region toward the other side over time. 
     In this vehicle headlight of the second aspect, it is brightened from one side in the horizontal direction of the predetermined region. Therefore, the adjustment of the light emitted from the plurality of light emitting units can be simplified as compared with the case where the light is brightened from both sides in the horizontal direction of the predetermined region. In addition, in a case where the predetermined region and a sign located on the road shoulder side overlap with each other and the partial region extends from the edge on the side where the sign is located in the horizontal direction, the sign can be recognized by the driver quickly. 
     In this case, a center of the predetermined region may be shifted from a center of the predetermined light distribution pattern in the horizontal direction to a predetermined side in the horizontal direction, and the partial region may expand from an edge on a side opposite to the predetermined side in the horizontal direction of the predetermined region toward the predetermined side over time. 
     Generally, the center in the horizontal direction in the light distribution pattern of the emitted light tends to be located on a vertical line passing through the center in the horizontal direction of the vehicle. Therefore, in this vehicle headlight of the second aspect, when switching from the second state to the first state, it can be brightened from the side closer to the vertical line passing through the center of the vehicle of both sides in the horizontal direction of the predetermined region. Therefore, according to the vehicle headlight of the second aspect, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region as compared with the case where it is brightened from the side farther from the vertical line passing through the center of the vehicle of both sides in the horizontal direction of the predetermined region. 
     In the vehicle headlight according to the second aspect, the partial region may expand from an entire circumference of an outer peripheral edge of the predetermined region toward an inner side of the predetermined region over time. 
     With such a configuration, the predetermined region can be brightened faster than a case where the partial region expands from a portion of the outer peripheral edge of the predetermined region. Therefore, a sign or the like overlapping with the predetermined region can be recognized by the driver more quickly. In addition, as compared with a case where a portion of the region extends from a portion of the outer peripheral edge of the predetermined region, it is possible to suppress the driver from feeling uncomfortable and to give the driver a sense of security. 
     The vehicle headlight according to the second aspect, the partial region may expand from an inner side of the predetermined region toward an outer peripheral side of the predetermined region over time. 
     In this vehicle headlight, it is brightened from the inside of the predetermined region. Therefore, according to the vehicle headlight of the second aspect, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region as compared with the case where it is brightened from the outer peripheral side of the predetermined region. 
     In this case, a speed at which the partial region expands downward may be faster than a speed at which the partial region expands upward. 
     In this vehicle headlight of the second aspect, when switching from the second state to the first state, the lower side in the predetermined region can be brightened faster than the upper side. Therefore, according to the vehicle headlight of the second aspect, for example, in a case where the predetermined region overlaps with a pedestrian, an obstacle, or the like on the road when the state is switched from the second state to the first state, the pedestrian, the obstacle, or the like can be recognized by the driver more quickly. 
     Alternatively, a speed at which the partial region expands upward may be faster than a speed at which the partial region expands downward. 
     In this vehicle headlight of the second aspect, when switching from the second state to the first state, the upper side in the predetermined region can be brightened faster than the lower side. Therefore, according to the vehicle headlight of the second aspect, for example, when the predetermined region and a sign overlap with each other at the time of switching from the second state to the first state, the sign can be recognized by the driver more quickly. 
     In the vehicle headlight according to the second aspect, when the state is switched from the second state to the first state, in a region other than the partial region in the predetermined region, a light amount may be increased over time such that an intensity of light decreases as a distance from the partial region increases. 
     As described above, in the vehicle headlight of the second aspect, when the state is switched from the second state to the first state, it is brightened from a partial region in the predetermined region, and the bright region expands over time. For this reason, by adopting the above configuration, it is possible to make the predetermined region darker as the distance from the bright region increases, and to make the boundary between the bright region and the dark region inconspicuous. Therefore, according to the vehicle headlight of the second aspect, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a plan view conceptually illustrating a vehicle including a vehicle headlight according to a first embodiment as a first aspect of the present invention. 
         FIG.  2    is a side view schematically illustrating a first lamp unit illustrated in  FIG.  1   . 
         FIG.  3    is a front view schematically illustrating a light distribution pattern forming unit illustrated in  FIG.  2   . 
         FIG.  4    is a view illustrating first irradiation spots irradiated with light from each light emitting element illustrated in  FIG.  3   . 
         FIG.  5    is a side view schematically illustrating a second lamp unit illustrated in  FIG.  1   . 
         FIG.  6    is a front view schematically illustrating a light distribution pattern forming unit illustrated in  FIG.  5   . 
         FIG.  7    is a diagram illustrating second irradiation spots irradiated with light from each light emitting element illustrated in  FIG.  6   . 
         FIG.  8    is a side view schematically illustrating a third lamp unit illustrated in  FIG.  1   . 
         FIG.  9    is a front view schematically illustrating a light source unit illustrated in  FIG.  8   . 
         FIG.  10    is a diagram illustrating a light distribution pattern of a low beam in the first embodiment. 
         FIG.  11    is a diagram illustrating a light distribution pattern of a high beam in the first embodiment. 
         FIG.  12    is a diagram illustrating an example of a control flowchart of a control unit according to the first embodiment. 
         FIG.  13    is a diagram illustrating an example of a predetermined region determined by a region determination unit. 
         FIG.  14    is an enlarged view of a predetermined region and its vicinity in  FIG.  13   . 
         FIG.  15    is a diagram illustrating an example of a light distribution pattern corresponding to the predetermined region illustrated in  FIG.  14   . 
         FIG.  16    is a cross-sectional view along a vertical direction schematically illustrating a second lamp unit according to a modification. 
         FIG.  17    is a plan view conceptually illustrating a vehicle including a vehicle headlight according to a third embodiment as a second aspect of the present invention. 
         FIG.  18    is a diagram illustrating a light distribution pattern of a high beam in a third embodiment. 
         FIG.  19    is a diagram illustrating an example of a control flowchart of a control unit according to the third embodiment. 
         FIG.  20    is a diagram illustrating an example of a light distribution pattern of light emitted when a preceding vehicle is detected as another vehicle by a detection device. 
         FIG.  21    is a diagram for explaining an example of a state in which a light distribution pattern changes according to another vehicle in the third embodiment. 
         FIG.  22    is a diagram for explaining an example of a state in which a light distribution pattern changes according to another vehicle in a fourth embodiment. 
         FIG.  23    is a diagram for explaining an example of a state in which a light distribution pattern changes according to another vehicle in a fifth embodiment. 
         FIG.  24    is a diagram for explaining an example of a state in which a light distribution pattern changes according to another vehicle in a sixth embodiment. 
         FIG.  25    is a diagram for explaining an example of a state in which a light distribution pattern changes according to another vehicle in a seventh embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments for implementing a vehicle headlight according to the present invention will be illustrated together with the accompanying drawings. The embodiments exemplified below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved from the following embodiments without departing from the gist thereof. In the accompanying drawings, the dimensions of each member may be exaggerated for easy understanding. 
     First Embodiment 
     A first embodiment as a first aspect of the present invention will be described.  FIG.  1    is a plan view conceptually illustrating a vehicle including a vehicle headlight of the present embodiment. As illustrated in  FIG.  1   , a vehicle  100  includes a vehicle headlight  1 , a detection device  110 , and a light switch  120 . 
     The vehicle headlight  1  of the present embodiment is a headlight for an automobile. The vehicle headlight  1  includes a pair of left and right lamp units  5 , a control unit CO, a determination unit  50 , a region determination unit  55 , and a pair of power supply circuits  60  as main components. In the present specification, unless otherwise specified, “right” means the right side from the viewpoint of the driver of the vehicle  100  that is the host vehicle, and “left” means the left side from the viewpoint of the driver of the vehicle  100  that is the host vehicle. 
     In the present embodiment, the pair of lamp units  5  have substantially symmetrical shapes in the horizontal direction of the vehicle  100 , and emit light of a light distribution pattern changeable toward the front of the vehicle  100 . In addition, the configuration of one of the lamp units  5  is the same as the configuration of the other lamp unit  5  except that the shape is substantially symmetrical. Therefore, one of the lamp units  5  will be described below, and the description of the other lamp unit  5  will be omitted. 
     The lamp unit  5  of the present embodiment includes a first lamp unit  10 , a second lamp unit  20 , and a third lamp unit  30 . These lamp units  10 ,  20 , and  30  are arranged side by side, the second lamp unit  20  is arranged on the most center side of the vehicle  100 , the third lamp unit  30  is arranged on the outermost side of the vehicle  100 , and the first lamp unit  10  is arranged between the second lamp unit  20  and the third lamp unit  30 . 
       FIG.  2    is a side view schematically illustrating the first lamp unit  10  illustrated in  FIG.  1   . As illustrated in  FIG.  1   , the first lamp unit  10  mainly includes a light distribution pattern forming unit  12 , a projection lens  15 , and a housing  16 . In  FIG.  2   , the housing  16  is illustrated in a vertical cross-section. 
     The housing  16  mainly includes a lamp housing  17 , a front cover  18 , and a back cover  19 . The front of the lamp housing  17  is opened, and the front cover  18  is fixed to the lamp housing  17  so as to close the opening. An opening smaller than that in the front is formed behind the lamp housing  17 , and the back cover  19  is fixed to the lamp housing  17  so as to close the opening. 
     A space formed by the lamp housing  17 , the front cover  18  closing the front opening of the lamp housing  17 , and the back cover  19  closing the rear opening of the lamp housing  17  is a lamp chamber  10 R, and the light distribution pattern forming unit  12  and the projection lens  15  are accommodated in the lamp chamber  10 R. 
       FIG.  3    is a front view schematically illustrating the light distribution pattern forming unit  12  illustrated in  FIG.  2   . As illustrated in  FIGS.  2  and  3   , the light distribution pattern forming unit  12  of the present embodiment includes a plurality of light emitting elements  13   a  to  13   h  as first light emitting units that emit light, and a circuit board  14  on which the plurality of light emitting elements  13   a  to  13   h  is mounted. The plurality of light emitting elements  13   a  to  13   h  are arranged in a line in the horizontal direction, and emit light forward. The plurality of light emitting elements  13   a  to  13   h  can individually change the amount of emitted light. In the present embodiment, the light emitting elements  13   a  to  13   h  are substantially rectangular LEDs whose light emission surfaces are elongated in the vertical direction, and the light distribution pattern forming unit  12  is a so-called LED array, and eight LEDs are arranged. Note that the type and number of light emitting elements are not particularly limited. 
     Such a light distribution pattern forming unit  12  can form a predetermined light distribution pattern by selecting the light emitting elements  13   a  to  13   h  that emit light. In addition, the light distribution pattern forming unit  12  can adjust the light intensity distribution in a predetermined light distribution pattern by adjusting the amount of light emitted from each of the light emitting elements  13   a  to  13   h . That is, it can be understood that the light distribution pattern forming unit  12  forms a predetermined light distribution pattern according to the amount of light emitted from the plurality of light emitting elements  13   a  to  13   h.    
     The projection lens  15  is a lens that adjusts a divergence angle of incident light. The projection lens  15  is disposed in front of the light distribution pattern forming unit  12 , light emitted from the light distribution pattern forming unit  12  is incident thereon, and a divergence angle of the light is adjusted by the projection lens  15 . The projection lens  15  is a lens in which an incident surface and an emission surface are formed in a convex shape. The optical axis of the projection lens  15  passes between the light emitting element  13   d  and the light emitting element  13   e  in the light distribution pattern forming unit  12 , and the rear focal point of the projection lens  15  is located on or near the surface including the light emission surface of the light emitting element  13   d . The light whose divergence angle is adjusted by the projection lens  15  is emitted from the first lamp unit  10  toward the front of the vehicle  100  via the front cover  18 . 
       FIG.  4    is a diagram illustrating first irradiation spots irradiated with the light from the light emitting elements  13   a  to  13   h  illustrated in  FIG.  3   . First irradiation spots S 1   a  to S 1   h  illustrated in  FIG.  4    are regions irradiated with the light from the light emitting elements  13   a  to  13   h  on a virtual vertical screen arranged 25 meters ahead of the vehicle  100 . In  FIG.  4   , S represents a horizontal line, and V represents a vertical line passing through the center of the vehicle  100  in the horizontal direction. As described above, because the plurality of light emitting elements  13   a  to  13   h  are arranged in line in the horizontal direction, the first irradiation spots S 1   a  to S 1   h  are arranged in line in the horizontal direction. Therefore, it can be understood that the first lamp unit  10  emits the light from the plurality of light emitting elements  13   a  to  13   h  such that the first irradiation spots S 1   a  to S 1   h  irradiated with the light from the light emitting elements  13   a  to  13   h  are aligned in the horizontal direction. The first irradiation spot S 1   a  corresponds to the light emitting element  13   a , and when light is emitted from light emitting element  13   a , the first irradiation spot S 1   a  is irradiated with the light. The first irradiation spot S 1   b  corresponds to the light emitting element  13   b , the first irradiation spot Sic corresponds to the light emitting element  13   c , the first irradiation spot S 1   d  corresponds to the light emitting element  13   d , the first irradiation spot S 1   e  corresponds to the light emitting element  13   e , the first irradiation spot Sif corresponds to the light emitting element  13   f , the first irradiation spot S 1   g  corresponds to the light emitting element  13   g , and the first irradiation spot S 1   h  corresponds to the light emitting element  13   h.    
     These first irradiation spots S 1   a  to S 1   h  have substantially the same size and have rectangular shapes elongated in the vertical direction. The adjacent first irradiation spots partially overlap with each other. For example, a portion of the first irradiation spot S 1   a  and a portion of the first irradiation spot S 1   b  overlap with each other, and another portion of the first irradiation spot S 1   b  and a portion of the first irradiation spot Sic overlap with each other. The first irradiation spots S 1   a  to S 1   h  overlap with the horizontal line S, and the two first irradiation spots S 1   d  and S 1   e  overlap with the vertical line V. In other words, the positions and the like of the light emitting elements  13   a  to  13   h  are adjusted such that the first irradiation spots S 1   a  to S 1   h  are arranged in this manner. The adjacent first irradiation spots may be in contact with each other or may be separated from each other to form a gap. However, it is preferable that these first irradiation spots S 1   a  to S 1   h  are arranged without a gap in the horizontal direction. The shapes of the first irradiation spots S 1   a  to S 1   h  are not particularly limited. 
       FIG.  5    is a side view schematically illustrating the second lamp unit  20  illustrated in  FIG.  1   . As illustrated in  FIG.  5   , the second lamp unit  20  mainly includes a light distribution pattern forming unit  22 , a projection lens  25 , and a housing  26 . In  FIG.  5   , the housing  26  is illustrated in a vertical cross-section. The housing  26  has a configuration similar to that of the housing  16  of the first lamp unit  10 , and mainly includes a lamp housing  27 , a front cover  28 , and a back cover  29 , and the light distribution pattern forming unit  22  and the projection lens  25  are accommodated in a lamp chamber  20 R formed by the housing  26 . 
       FIG.  6    is a front view schematically illustrating the light distribution pattern forming unit  22  illustrated in  FIG.  5   . As illustrated in  FIGS.  5  and  6   , the light distribution pattern forming unit  22  of the present embodiment includes a plurality of light emitting elements  23  as second light emitting units that emit light, and a circuit board  24  on which the plurality of light emitting elements  23  is mounted. The plurality of light emitting elements  23  are arranged in a matrix to form rows in the vertical direction and the horizontal direction, and emit light forward. These light emitting elements  23  are smaller than the light emitting elements  13   a  to  13   h  in the first lamp unit  10 , and can individually change the amount of emitted light. In the present embodiment, the light distribution pattern forming unit  22  has thirty-two light emitting element groups each including ninety-six light emitting elements  23  arranged in the horizontal direction, and these light emitting element groups are arranged in the vertical direction. In addition, these light emitting elements  23  are micro LEDs, and the light distribution pattern forming unit  22  is a so-called micro LED array. Note that the number of light emitting elements  23  in each light emitting element group and the number of light emitting element groups are not particularly limited. 
     Such a light distribution pattern forming unit  22  can form a predetermined light distribution pattern by selecting the light emitting elements  23  that emit light. In addition, the light distribution pattern forming unit  22  can adjust the light intensity distribution in a predetermined light distribution pattern by adjusting the amount of light emitted from each of the light emitting elements  23 . That is, it can be understood that the light distribution pattern forming unit  22  forms a predetermined light distribution pattern according to the amount of light emitted from the plurality of light emitting elements  23 . 
     Similarly to the projection lens  15 , the projection lens  25  is a lens that adjusts a divergence angle of incident light. The projection lens  25  is disposed in front of the light distribution pattern forming unit  22 , light emitted from the light distribution pattern forming unit  22  is incident thereon, and a divergence angle of the light is adjusted by the projection lens  25 . The projection lens  25  is a lens in which the incident surface and the emission surface are formed in a convex shape, and the rear focal point of the projection lens  25  is located on or near the light emission surface of any one of the light emitting elements  23  in the light distribution pattern forming unit  22 . The light whose divergence angle is adjusted by the projection lens  25  is emitted from the second lamp unit  20  toward the front of the vehicle  100  via the front cover  28 . 
       FIG.  7    is a diagram illustrating second irradiation spots irradiated with the light from the light emitting elements  23  illustrated in  FIG.  6   . The second irradiation spot S 2  illustrated in  FIG.  7    is a region irradiated with the light from the light emitting element  23  on a virtual vertical screen arranged 25 meters ahead of the vehicle  100 . In  FIG.  7   , S represents a horizontal line, V represents a vertical line passing through the center of the vehicle  100  in the horizontal direction, and the first irradiation spots S 1   a  to S 1   h  are indicated by broken lines. Since the plurality of light emitting elements  23  in the light distribution pattern forming unit  22  are arranged in a matrix as described above, the second irradiation spots S 2  irradiated with the light from the respective light emitting elements  23  are arranged in a matrix in front of the vehicle  100 . Therefore, it can be understood that the second lamp unit  20  emits light from the plurality of light emitting elements  23  such that the second irradiation spots S 2  irradiated with the light from the respective light emitting elements  23  are arranged in a matrix. For easy understanding, the number of the plurality of second irradiation spots S 2  is reduced in  FIG.  7   . Each second irradiation spot S 2  corresponds to one light emitting element  23 , and the relative position of a specific light emitting element  23  in the plurality of light emitting elements  23  and the relative position of the specific second irradiation spot S 2  corresponding to the specific light emitting element  23  in the plurality of second irradiation spots S 2  are reversed vertically and horizontally. For example, the second irradiation spot S 2  corresponding to the light emitting element  23  located at the upper right end of the viewpoint of the driver of the vehicle  100  is located at the lower left end of the viewpoint of the driver of the vehicle  100 . 
     These second irradiation spots S 2  have square shapes of substantially the same size. In  FIG.  7   , for easy understanding, the plurality of second irradiation spots S 2  are illustrated such that adjacent second irradiation spots S 2  are in contact with each other, but adjacent second irradiation spots S 2  overlap with each other. The region  70  formed by the whole second irradiation spots S 2  has a rectangular shape elongated in the horizontal direction. That is, it can be understood that the region  70  is a region that can be irradiated with light from the second lamp unit  20 . The region  70  overlaps with the horizontal line S and the vertical line V, and also overlaps with the six first irradiation spots S 1   b  to S 1   g . Each of the six first irradiation spots S 1   b  to S 1   g  overlaps with at least one of the second irradiation spots S 2 , and in the present embodiment, overlaps with the plurality of second irradiation spots S 2 . In other words, the orientation and the like of the second lamp unit  20  are adjusted such that the region  70  formed by the second irradiation spots S 2  is arranged in this manner. Adjacent second irradiation spots S 2  may be in contact with each other or may be separated from each other to form a gap. However, it is preferable that the plurality of second irradiation spots S 2  are arranged in a matrix without a gap. The shape of the second irradiation spot S 2  is not particularly limited as long as the second irradiation spot S 2  is smaller than the first irradiation spots S 1   a  to S 1   h . The plurality of second irradiation spots S 2  may include second irradiation spots S 2  having different sizes and shapes. At least one first irradiation spot among the eight first irradiation spots S 1   a  to S 1   h  may overlap with at least one second irradiation spot S 2 , and all the irradiation spots S 1   a  to S 1   h  may overlap with the second irradiation spot S 2 . 
       FIG.  8    is a side view schematically illustrating the third lamp unit  30  illustrated in  FIG.  1   . As illustrated in  FIG.  8   , the third lamp unit  30  mainly includes a light source unit  32 , a shade  33 , a projection lens  35 , and a housing  36 . In  FIG.  8   , the housing  36  is illustrated in a vertical cross-section. The housing  36  has a configuration similar to that of the housing  16  of the first lamp unit  10 , and mainly includes a lamp housing  37 , a front cover  38 , and a back cover  39 . The light source unit  32 , the shade  33 , and the projection lens  35  are accommodated in a lamp chamber  30 R formed by the housing  36 . 
       FIG.  9    is a front view schematically illustrating the light source unit  32  illustrated in  FIG.  8   . Note that the shade  33  is also illustrated in  FIG.  9   . As illustrated in  FIGS.  8  and  9   , the light source unit  32  of the present embodiment includes a light emitting element  32   a  that emits light and a circuit board  32   b  on which the light emitting element  32   a  is mounted. In the present embodiment, the light emitting element  32   a  is a substantially rectangular LED whose light emission surface is long in the horizontal direction, and emits light forward. 
     The shade  33  includes a light shielding portion  33   a  and a fixing portion  33   b . In the present embodiment, the light shielding portion  33   a  and the fixing portion  33   b  are integrally formed by bending a plate-shaped member. The light shielding portion  33   a  extends in the horizontal direction in front of the light emitting element  32   a  of the light source unit  32 , and the fixing portion  33   b  is connected to a lower end portion thereof. The fixing portion  33   b  extends rearward from a lower end portion of the light shielding portion  33   a , and an end portion of the fixing portion  33   b  on a side opposite to the light shielding portion  33   a  side is fixed to the circuit board  32   b . The upper edge of the light shielding portion  33   a  includes a first edge portion  33   e   1 , a second edge portion  33   e   2 , and a third edge portion  33   e   3 . The first edge portion  33   e   1  extends in a substantially horizontal direction. The second edge portion  33   e   2  extends linearly and downward from an end on one side of the first edge portion  33   e   1  toward the side opposite to the first edge portion  33   e   1 . The third edge portion  33   e   3  extends in the substantially horizontal direction from the end of the second edge portion  33   e   2  on the side opposite to the first edge portion  33   e   1  toward the side opposite to the first edge portion  33   e   1 . The light shielding portion  33   a  of such a shade  33  shields a portion of the light emitted from the light emitting element  32   a.    
     Similarly to the projection lens  15 , the projection lens  35  is a lens that adjusts a divergence angle of incident light. In the present embodiment, the projection lens  35  is a lens in which the incident surface and the emission surface are formed in a convex shape, and is disposed in front of the shade  33 . The rear focal point of the projection lens  35  is located on or near the upper edge of the light shielding portion  33   a  of the shade  33 . As described above, a portion of the light emitted from the light emitting element  32   a  is shielded by the light shielding portion  33   a  of the shade  33 , another portion of the light emitted from the light emitting element  32   a  is incident on the projection lens  35 , and light of a specific light distribution pattern corresponding to the shape of the light shielding portion  33   a  is emitted from the projection lens  35 . Note that this specific light distribution pattern is a light distribution pattern in which a light distribution pattern when a portion of light is shielded by the light shielding portion  33   a  is reversed vertically and horizontally. As described above, the light having the specific light distribution pattern emitted from the projection lens  35  is emitted from the third lamp unit  30  toward the front of the vehicle  100  via the front cover  38 . 
     Next, as the control unit CO illustrated in  FIG.  1   , for example, an integrated circuit such as a microcontroller, an integrated circuit (IC), a large-scale integrated circuit (LSI), or an application specific integrated circuit (ASIC), or a numerical control (NC) device can be used. In addition, when the NC device is used, the control unit CO may use a machine learning device or may not use a machine learning device. As described later, the control unit CO controls the first lamp unit  10 , the second lamp unit  20 , and the third lamp unit  30 . 
     The light switch  120  included in the vehicle  100  is connected to the control unit CO. The light switch  120  of the present embodiment is a switch that selects one of emission of a low beam, emission of a high beam, and non-emission of light. For example, the light switch  120  outputs a signal indicating emission of a low beam to the control unit CO in a case where emission of a low beam is selected, and outputs a signal indicating emission of a high beam to the control unit CO in a case where emission of a high beam is selected. In addition, the light switch  120  does not output a signal to the control unit CO when non-emission of light is selected. 
     The detection device  110  of the present embodiment detects another vehicle located in front of the vehicle  100 . When detecting another vehicle, the detection device  110  outputs a signal indicating detection of the other vehicle to the region determination unit  55  via the determination unit  50 . The detection device  110  also detects the state of another vehicle detected, and outputs a signal indicating the state of the other vehicle to the region determination unit  55  via the determination unit  50 . Note that the detection device  110  may directly output these signals to the region determination unit  55 . Examples of the state of the other vehicle include a position of the other vehicle with respect to the vehicle  100 , whether the other vehicle is a preceding vehicle or an oncoming vehicle, a distance from the vehicle  100  to the other vehicle, and the like. The detection device  110  includes, for example, a camera, a detection unit, and the like (not illustrated). The camera is attached to the front portion of the vehicle  100 , and captures an image of the front of the vehicle  100  at predetermined time intervals, for example, 1/30 second intervals. The captured image captured by the camera includes at least a portion of a region irradiated with light emitted from the pair of lamp units  5 . The detection unit detects another vehicle located in front of the vehicle  100  and detects a state of the other vehicle from the captured image captured by the camera. 
     For example, when the other vehicle is an oncoming vehicle, a pair of white light spots due to light emitted from a headlight of the oncoming vehicle appear in the captured image. The detection unit outputs a signal indicating detection of another vehicle and a signal indicating that the other vehicle is an oncoming vehicle to the determination unit  50 , assuming that the pair of white light spots correspond to light from the headlight of the oncoming vehicle. The detection unit may output a signal indicating that the other vehicle is an oncoming vehicle assuming that the signal indicating that the other vehicle is an oncoming vehicle includes detection of the other vehicle. In addition, the detection unit calculates the distance from the vehicle  100  to the oncoming vehicle on the basis of the distance between the pair of white light spots and the like. Then, the detection unit outputs a signal indicating the positions of a pair of white light spots in the captured image as a signal indicating the position of the oncoming vehicle with respect to the vehicle  100  and a signal indicating the calculated distance to the determination unit  50 . In addition, in a case where the other vehicle is a preceding vehicle, a pair of red light spots due to light emitted from the tail light of the preceding vehicle appear in the captured image. The detection unit outputs a signal indicating detection of another vehicle and a signal indicating that the other vehicle is a preceding vehicle to the determination unit  50 , assuming that a pair of red light spots correspond to light from the tail light of the preceding vehicle. The detection unit may output a signal indicating that the other vehicle is a preceding vehicle assuming that the signal indicating that the other vehicle is a preceding vehicle includes detection of the other vehicle. In addition, the detection unit calculates the distance from the vehicle  100  to the preceding vehicle on the basis of the distance between the pair of red light spots and the like. Then, the detection unit outputs, to the determination unit  50 , a signal indicating the positions of a pair of red light spots in the captured image as a signal indicating the position of the preceding vehicle with respect to the vehicle  100 , and a signal indicating the calculated distance. 
     On the other hand, when the detection unit does not detect another vehicle located in front of the vehicle  100 , the detection unit does not output a signal to determination unit  50 . 
     Examples of the configuration of the detection unit include a configuration similar to that of the control unit CO, and examples of the camera include a complementary metal oxide semiconductor (C-MOS) camera and a charged coupled device (CCD) camera. 
     Note that the configuration of the detection device  110 , the method of detecting another vehicle by the detection device  110 , the method of calculating the distance from the vehicle  100  to the other vehicle, the method of identifying an oncoming vehicle and a preceding vehicle, and the signal indicating the state of the other vehicle output from the detection device  110  to the determination unit  50  are not particularly limited. For example, the detection device  110  may further include an image processing unit that performs image processing on the captured image captured by the camera, and the detection unit may detect another vehicle and detect the state of the other vehicle from the information subjected to the image processing by the image processing unit. Furthermore, the detection device  110  may further include a millimeter-wave radar, a LIDAR, or the like capable of detecting an object located in front of the vehicle  100 , and may detect another vehicle located in front of the vehicle  100  and detect a state of the other vehicle on the basis of a captured image captured by a camera and a signal input from the millimeter-wave radar, the LIDAR, or the like. 
     The determination unit  50  determines whether the detected other vehicle satisfies a predetermined requirement based on a signal indicating a state of the other vehicle from detection device  110  that detects the other vehicle located in front of the vehicle  100 . Examples of the predetermined requirement include that a distance between another vehicle and the vehicle  100  is less than a predetermined distance, a headlight of an oncoming vehicle is turned on, a tail light of a preceding vehicle is turned on, and at least two of these requirements are satisfied. The predetermined requirement of the present embodiment is that a distance between another vehicle and the vehicle  100  is less than a predetermined distance, and the predetermined distance is, for example, 100 m. The predetermined distance may be different between a case where the other vehicle is a preceding vehicle and a case where the other vehicle is an oncoming vehicle. In a case where the other vehicle satisfies the predetermined requirement, the determination unit  50  of the present embodiment outputs, as a signal indicating the state of the other vehicle, a signal indicating information such as a captured image obtained by capturing the other vehicle and an existing position of the other vehicle in the captured image to the region determination unit  55 . In addition, when the other vehicle does not satisfy the predetermined requirement and when no signal is input from the detection device  110  to the determination unit  50 , the determination unit  50  does not output a signal to the region determination unit  55 . Therefore, the determination by the determination unit  50  can be understood as changing the signal to be output in a case-by-case manner according to the signal input from the detection device  110  as described above. Examples of the configuration of the determination unit  50  include the same configuration as the control unit CO. 
     Based on the signal indicating the state of the other vehicle output from the detection device  110  via the determination unit  50 , the region determination unit  55  determines a predetermined region overlapping with a visual recognition portion for the driver of the other vehicle to visually recognize the outside of the vehicle, and outputs a signal indicating the predetermined region to the control unit CO. Therefore, this predetermined region is not a region determined in advance. However, the region determination unit  55  may select a region to be the predetermined region from a plurality of predetermined regions based on a signal indicating a state of another vehicle from the determination unit  50 , and determine the region as the predetermined region. Examples of the visual recognition portion for the driver of the other vehicle to visually recognize the outside of the vehicle include a front window in a case where the other vehicle is an oncoming vehicle, and include a side mirror, a rear-view mirror, and an imaging device that images the rear of the vehicle in a case where the other vehicle is a preceding vehicle. The predetermined region preferably overlaps with the entire visual recognition portion of such another vehicle. In the present embodiment, the region determination unit  55  determines a rectangular region including the entire other vehicle as a predetermined region on a virtual vertical screen arranged 25 meters ahead of the vehicle  100 . A predetermined gap is formed between the outer edge of the predetermined region and the outer edge of another vehicle. The region determination unit  55  determines such a predetermined region. On the other hand, when the signal indicating the state of the other vehicle is not input, the region determination unit  55  does not output a signal to the control unit CO. In this case, the region determination unit  55  may output a signal indicating that the predetermined region is not determined to the control unit CO. Examples of the configuration of the region determination unit  55  include the same configuration as the control unit CO. Note that the region determination unit  55  may also serve as the determination unit  50 . The shape of the predetermined region is not particularly limited. 
     One power supply circuit  60  corresponds to one lamp unit  5 , and the other power supply circuit  60  corresponds to the other lamp unit  5 . Each of the power supply circuits  60  includes a driver, and when a signal is input from the control unit CO, the driver adjusts power supplied to each of the light emitting elements  13   a  to  13   h  of the first lamp unit  10 , each of the light emitting elements  23  of the second lamp unit  20 , and the light emitting element  32   a  of the third lamp unit  30 . In this way, the amount of light emitted from each of the light emitting elements  13   a  to  13   h ,  23 , and  32   a  is adjusted. The driver of the power supply circuit  60  may adjust the power supplied to each of the light emitting elements  13   a  to  13   h ,  23 , and  32   a  by pulse width modulation (PWM) control. In this case, the amount of light emitted from each of the light emitting elements  13   a  to  13   h ,  23 , and  32   a  is adjusted by adjusting the duty cycle. 
     Next, a low beam emitted from the vehicle headlight  1  will be described. 
     In the present embodiment, a light distribution pattern of a low beam is formed by the light emitted from the second lamp unit  20  and the light emitted from the third lamp unit  30 . 
       FIG.  10    is a diagram illustrating a light distribution pattern of a low beam in the present embodiment. In  FIG.  10   , S indicates a horizontal line, V indicates a vertical line passing through the center of the vehicle  100  in the horizontal direction, and a light distribution pattern PL of a low beam formed on a virtual vertical screen arranged 25 meters ahead of the vehicle  100  is indicated by a thick line. In  FIG.  10   , a region  70  that can be irradiated with the light from the second lamp unit  20  is indicated by a broken line. 
     The light distribution pattern PL of the low beam of the present embodiment has cutoff lines CL 1 , CL 2 , and CL 3  at the upper edge. The cutoff line CL 1  extends in the horizontal direction to the right side, which is one side in the horizontal direction, from an elbow point EP located below the horizontal line S and on or near the vertical line V. The cutoff line CL 2  extends obliquely upward from the elbow point EP to the left side which is the other side in the horizontal direction, and an end of the cutoff line CL 2  on the side opposite to the elbow point EP is located above the horizontal line S. The cutoff line CL 3  extends in the horizontal direction from an end of the cutoff line CL 2  opposite to the elbow point EP side to the other side in the horizontal direction. In addition, a hot zone HZL, which is a region having the highest light intensity in the light distribution pattern PL of the low beam, is located in the vicinity of the elbow point EP. In a country or an area where right-hand traffic of the vehicle is used, the light distribution pattern of the low beam has a substantially symmetrical shape with the light distribution pattern PL of the low beam illustrated in  FIG.  10   , the cutoff line CL 1  extends horizontally to the left from the elbow point EP, and the cutoff line CL 2  extends obliquely upward to the right from the elbow point EP. 
     The shape of the upper end of the light shielding portion  33   a  of the shade  33  in the third lamp unit  30  corresponds to the upper edge of the light distribution pattern PL of the low beam, and the outer shape of the specific light distribution pattern of the light emitted from the third lamp unit  30  substantially matches the outer shape of the light distribution pattern PL of the low beam. In addition, in the light distribution pattern PL of the low beam, the hot zone HZL is included in an overlapping region  71  overlapping with the region  70  that can be irradiated with the light from the second lamp unit  20 , and the overlapping region  71  is irradiated with the light from the second lamp unit  20 . In other words, light is emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  located in the overlapping region  71 , and the overlapping region  71  is irradiated with the light from the second lamp unit  20  and the light from the third lamp unit  30 . The light intensity distribution in the overlapping region  71  is, for example, a distribution in which the intensity decreases as the distance from the hot zone HZL increases. The amount of the light emitted from each light emitting element  23  is adjusted by the control unit CO so that the light intensity distribution in the overlapping region  71  has such a distribution. As described above, light is emitted from the second lamp unit  20  and the third lamp unit  30 , whereby a low beam is emitted from the vehicle headlight  1 . 
     Next, the high beam emitted from the vehicle headlight  1  will be described. 
     In the present embodiment, a light distribution pattern of a high beam is formed by the light emitted from the first lamp unit  10 , the light emitted from the second lamp unit  20 , and the light emitted from the third lamp unit  30 . 
       FIG.  11    is a diagram illustrating a light distribution pattern of a high beam in the present embodiment. In  FIG.  11   , S indicates a horizontal line, V indicates a vertical line passing through the center of the vehicle  100  in the horizontal direction, and a light distribution pattern PH of a high beam formed on a virtual vertical screen arranged 25 meters ahead of the vehicle  100  is indicated by a thick line. In  FIG.  11   , a region  70  that can be irradiated with the light from the second lamp unit  20  is indicated by a broken line together with the first irradiation spots S 1   a  to S 1   h . In the present embodiment, the hot zone HZH, which is the region having the highest light intensity in the light distribution pattern PH of the high beam, is located on or near the intersection of the horizontal line S and the vertical line V, and overlaps with the two first irradiation spots S 1   d  and S 1   e  and the region  70 . 
     In the present embodiment, when a high beam is emitted from the vehicle headlight  1 , light is emitted from all the light emitting elements  13   a  to  13   h  in the first lamp unit  10  and from all the light emitting elements  23  in the second lamp unit  20 . Therefore, the first irradiation spots S 1   a  to S 1   h  are irradiated with the light from the corresponding light emitting elements  13   a  to  13   h , and the region  70  is irradiated with the light from the light emitting element  23 . In addition, the third lamp unit  30  emits the same light as when forming the low beam. The light intensity distribution in the region overlapping with the region  70  in the light distribution pattern PH of the high beam is, for example, a distribution in which the intensity decreases as the distance from the hot zone HZH increases. The amount of light emitted from each light emitting element  23  is adjusted by the control unit CO so that the intensity of light in the region  70  has such a distribution. As described above, light is emitted from the first lamp unit  10 , the second lamp unit  20 , and the third lamp unit  30 , whereby a high beam is emitted from the vehicle headlight  1 . 
     Next, the operation of the vehicle headlight  1  of the present embodiment will be described.  FIG.  12    is a diagram illustrating an example of a control flowchart of the control unit according to the present embodiment. As illustrated in  FIG.  12   , the control flow of the present embodiment includes steps SP 11  to SP 17 . 
     (Step SP 11 ) 
     First, the control unit CO determines whether a signal indicating emission of a low beam is input from the light switch  120 . When this signal is input to the control unit CO, the control unit CO advances the control flow to step SP 12 . On the other hand, when this signal is not input to the control unit CO, the control unit CO advances the control flow to step SP 13 . For this reason, the determination of the control unit CO can be understood as changing the step to proceed to the next in a case-by-case manner according to the input signal. 
     (Step SP 12 ) 
     In this step, the control unit CO controls the first lamp unit  10 , the second lamp unit  20 , and the third lamp unit  30  so that a low beam is emitted from the vehicle headlight  1 . Specifically, the control unit CO outputs a predetermined control signal corresponding to the low beam to the power supply circuit  60 . As a result, the supply of power to all the light emitting elements  13   a  to  13   h  is stopped by the driver of the power supply circuit  60 , and the power supplied to the light emitting elements  32   a  is adjusted to be predetermined power, and the power supplied to each light emitting element  23  is adjusted to be power corresponding to a low beam. Therefore, light to be a portion of the low beam is emitted from the second lamp unit  20 , and light to be another portion of the low beam is emitted from the third lamp unit  30 , so that the low beam is emitted from the vehicle headlight  1 . Then, the control unit CO returns the control flow to step SP 11 . 
     (Step SP 13 ) 
     In this step, the control unit CO determines whether or not a signal indicating emission of a high beam is input from the light switch  120 . When this signal is input to the control unit CO, the control unit CO advances the control flow to step SP 14 . On the other hand, when this signal is not input to the control unit CO, the control unit CO advances the control flow to step SP 17 . 
     (Step SP 14 ) 
     In this step, the control unit CO determines whether the predetermined region is determined by the region determination unit  55  based on the signal input from the region determination unit  55 . In a case where the signal is not input from the region determination unit  55  to the control unit CO, the control unit CO advances the control flow to step SP 15 . On the other hand, when a signal is input from the region determination unit  55  to the control unit CO, the control unit CO advances the control flow to step SP 16 . 
     (Step SP 15 ) 
     In this step, the control unit CO controls the first lamp unit  10 , the second lamp unit  20 , and the third lamp unit  30  so that a high beam is emitted from the vehicle headlight  1 . Specifically, the control unit CO outputs a predetermined control signal corresponding to the high beam to the power supply circuit  60 . As a result, the driver of the power supply circuit  60  adjusts the power supplied to each of the light emitting elements  13   a  to  13   h  of the light distribution pattern forming unit  12  to a predetermined power, the power supplied to the light emitting element  32   a  of the light source unit  32  to a predetermined power, and the power supplied to each of the light emitting elements  23  of the light distribution pattern forming unit  22  to a power corresponding to a high beam. Therefore, light to be a portion of the high beam is emitted from the first lamp unit  10 , light to be another portion of the high beam is emitted from the second lamp unit  20 , and light to be another portion of the high beam is emitted from the third lamp unit  30 , whereby the low beam is emitted from the vehicle headlight  1 . Then, the control unit CO returns the control flow to step SP 11 . As described above, the light distribution pattern of the light emitted from the third lamp unit  30  is the same specific light distribution pattern as the light distribution pattern of the light emitted from the third lamp unit  30  when a low beam is emitted from the vehicle headlight  1 . 
     (Step SP 16 ) 
     In this step, the control unit CO controls the first lamp unit  10 , the second lamp unit  20 , and the third lamp unit  30  so that the light distribution pattern of the light emitted from the vehicle headlight  1  becomes a light distribution pattern corresponding to the predetermined region determined by the region determination unit  55 . Then, the control unit CO returns the control flow to step SP 11 . 
       FIG.  13    is a diagram illustrating an example of a predetermined region  80  determined by the region determination unit  55 , and is a diagram illustrating an example of the predetermined region  80  determined when the other vehicle  90  that is an oncoming vehicle is detected by the detection device  110  and the determination unit  50  determines that the other vehicle  90  satisfies a predetermined requirement.  FIG.  14    is an enlarged view of the predetermined region  80  and its vicinity in  FIG.  13   . In  FIG.  13   , S indicates a horizontal line, V indicates a vertical line passing through the center of the vehicle  100  in the horizontal direction, and the predetermined region  80  on a virtual vertical screen arranged 25 meters ahead of the vehicle  100  is indicated by a thick line. In  FIG.  13   , the first irradiation spots S 1   a  to S 1   h  are indicated by alternate long and short dash lines, and the region  70  is indicated by a broken line. In  FIG.  14   , the second irradiation spots S 2  are indicated by a thin line. For easy understanding, the number of second irradiation spots S 2  is reduced in  FIG.  14   . The plurality of second irradiation spots S 2  are illustrated such that adjacent second irradiation spots S 2  are in contact with each other, but adjacent second irradiation spots S 2  overlap with each other. 
     As described above, in the present embodiment, the predetermined region  80  has a rectangular shape including the entire other vehicle  90  that is an oncoming vehicle, and a predetermined gap is formed between the outer edge of the predetermined region  80  and the outer edge of the other vehicle  90 . For this reason, the predetermined region  80  overlaps with a front window  91  as a visual recognition portion for the driver of the other vehicle  90 , which is an oncoming vehicle, to visually recognize the outside of the vehicle. The control unit CO controls the first lamp unit  10  according to the positional relationship between the predetermined region  80  and the first irradiation spots S 1   a  to S 1   h . Specifically, the control unit CO controls the light emitting elements  13   e  and  13   f  such that the amount of light emitted from the light emitting elements  13   e  and  13   f  corresponding to the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  is reduced or becomes 0 as compared with the amount of light when a high beam is emitted. In addition, the control unit CO controls the light emitting elements  13   a  to  13   d ,  13   g , and  13   h  such that the amount of light emitted from the light emitting elements  13   a  to  13   d ,  13   g , and  13   h  corresponding to the first irradiation spots S 1   a  to S 1   d , S 1   g , and S 1   h  not overlapping with the predetermined region  80  becomes the amount of light when a high beam is emitted. Specifically, the control unit CO outputs a control signal to the power supply circuit  60  so that the amount of the light emitted from each of the light emitting elements  13   a  to  13   h  becomes such a light amount, and the power supplied to each of the light emitting elements  13   a  to  13   h  is adjusted by the driver of the power supply circuit  60 . In the present embodiment, the control unit CO controls the first lamp unit  10  so that the amount of light emitted from the light emitting elements  13   e  and  13   f  becomes zero. 
     Further, the control unit CO controls the second lamp unit  20  according to the positional relationship between the predetermined region  80  and the second irradiation spot S 2 . Specifically, the control unit CO controls the light emitting element  23  such that the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  overlapping with the predetermined region  80  is smaller than the light amount when a high beam is emitted. In addition, the control unit CO controls the light emitting element  23  so that light is emitted from the light emitting element  23  corresponding to the hatched second irradiation spot S 2  made up of a plurality of points in  FIG.  14   . The hatched second irradiation spot S 2  overlaps with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  and does not overlap with the predetermined region  80 . Further, the control unit CO controls the light emitting element  23  such that the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  not overlapping with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  becomes the same as the light amount when a high beam is emitted. Specifically, the control unit CO outputs a control signal to the power supply circuit  60  such that the amount of light emitted from each light emitting element  23  becomes as described above, and the power supplied to each light emitting element  23  is adjusted by the driver of the power supply circuit  60 . In the present embodiment, the control unit CO controls the second lamp unit  20  so that the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  overlapping with the predetermined region  80  becomes zero, and the amount of the light from the light emitting element  23  corresponding to the hatched second irradiation spot S 2  becomes the same as the light amount when a high beam is emitted. However, the amount of the light from the light emitting element  23  corresponding to the hatched second irradiation spot S 2  may be different from the light amount when a high beam is emitted. 
     Further, the control unit CO controls the third lamp unit  30  so that light having the same specific light distribution pattern as the light distribution pattern of the light emitted from the third lamp unit  30  is emitted when a high beam is emitted regardless of the predetermined region  80 . 
       FIG.  15    is a diagram illustrating an example of the light distribution pattern corresponding to the predetermined region  80  illustrated in  FIG.  14   . In  FIG.  15   , S indicates a horizontal line, V indicates a vertical line passing through the center of the vehicle  100  in the horizontal direction, and a light distribution pattern  200  on a virtual vertical screen arranged 25 meters ahead of the vehicle  100  is indicated by a thick line. As described above, the amount of the light emitted from the light emitting elements  13   a  to  13   d ,  13   g , and  13   h  corresponding to the first irradiation spots S 1   a  to S 1   d , S 1   g , and S 1   h  other than the first irradiation spots S 1   e  and Sif and the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  not overlapping with the first irradiation spots S 1   e  and Sif are the same as the light amount when a high beam is emitted. The light emitted from the third lamp unit  30  is the same as the light when a high beam is emitted. Therefore, the light distribution pattern  200  is a light distribution pattern in which the light intensity distribution in the region overlapping with the first irradiation spots S 1   e  and Sif changes in the light distribution pattern PH of the high beam. As described above, the amount of the light emitted from the light emitting elements  13   e  and  13   e  corresponding to the first irradiation spots S 1   e  and Sif overlapping with the predetermined region  80  and the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  overlapping with the predetermined region  80  are smaller than the light amount when a high beam is emitted. Therefore, the light distribution pattern  200  includes the predetermined region  80  and has a light reduction region  81  in which the light amount is reduced as compared with the case of emitting a high beam, and the light reduction region  81  overlaps with the front window  91  as the visual recognition portion in the other vehicle  90 . 
     (Step SP 17 ) 
     In this step, no signal is input from the light switch  120  to the control unit CO. Therefore, non-emission of light is selected in the light switch  120 . The control unit CO controls the lamp units  10 ,  20 , and  30  so that no light is emitted from the first lamp unit  10 , the second lamp unit  20 , and the third lamp unit  30 . Specifically, the control unit CO outputs a predetermined signal to the power supply circuit  60 , causes the power supply circuit  60  to stop the supply of power to all the light emitting elements  13   a  to  13   h , all the light emitting elements  23 , and the light emitting element  32   a , and does not emit light from the vehicle headlight  1 . Then, the control flow returns to step SP 11 . 
     As described above, in the vehicle headlight  1  of the present embodiment, the light distribution pattern PH of the emitted high beam is changed to a light distribution pattern  200  having the light reduction region  81  when the predetermined region  80  is determined by the region determination unit  55 . Note that the control flow of the control unit CO is not particularly limited. 
     By the way, in the vehicle headlight described in Patent Literature 1 described above, light is not emitted to a surrounding region together with other vehicles, and thus forward visibility tends to decrease. 
     Therefore, the vehicle headlight  1  of the present embodiment includes the first lamp unit  10 , the second lamp unit  20 , the region determination unit  55 , and the control unit CO. The first lamp unit  10  includes a plurality of light emitting elements  13   a  to  13   h  capable of individually changing the amount of light emitted, and emits light from the plurality of light emitting elements  13   a  to  13   h  such that first irradiation spots S 1   a  to S 1   h  irradiated with the light from the respective light emitting elements  13   a  to  13   h  are aligned in the horizontal direction. The second lamp unit  20  includes a plurality of light emitting elements  23  capable of individually changing the amount of light emitted, and emits light from the plurality of light emitting elements  23  so that second irradiation spots S 2  irradiated with the light from the respective light emitting elements  23  are arranged in a matrix. The region determination unit  55  determines a predetermined region  80  that overlaps with a visual recognition portion for the driver of the other vehicle  100  to visually recognize the outside of the vehicle when a signal indicating detection of the other vehicle  90  located in front of the vehicle  90  is input from the detection device  110 . The second irradiation spot S 2  is smaller than the first irradiation spots S 1   a  to S 1   h , and the first irradiation spots S 1   b  to S 1   g  overlap with a plurality of second irradiation spots S 2 . When the predetermined region  80  is not determined by the region determination unit  55 , the control unit CO controls the first lamp unit  10  and the second lamp unit  20  so that light is emitted from the first lamp unit  10  and the second lamp unit  20 . Further, when the predetermined region  80  is determined by the region determination unit  55 , the control unit CO controls the first lamp unit  10  so that the amount of light emitted from the light emitting elements  13   e  and  13   f  corresponding to the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  is reduced or becomes zero. In this case, the control unit CO controls the second lamp unit  20  so that the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  overlapping with the predetermined region  80  is reduced or becomes zero, and the light is emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  overlapping with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  and not overlapping with the predetermined region  80 . 
     In the vehicle headlight  1  of the present embodiment, the amount of light emitted from the first lamp unit  10  and irradiated on the visual recognition portion of the other vehicle  90  is reduced or becomes zero, and the amount of light emitted from the second lamp unit  20  and irradiated on the visual recognition portion of the other vehicle  90  is reduced or becomes zero. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress dazzling of the occupant of the other vehicle  90 . In addition, in the vehicle headlight  1  of the present embodiment, the second irradiation spot S 2  overlapping with the first irradiation spots S 1   e  and S 1   f  in which the amount of the emitted light is reduced and not overlapping with the predetermined region  80  is irradiated with light. Therefore, at least a portion of the region that does not overlap with the predetermined region  80  among the first irradiation spots S 1   e  and S 1   f  in which the amount of the emitted light is reduced can be irradiated with the light from the second lamp unit  20 . Therefore, according to the vehicle headlight  1  of the present embodiment, the forward visibility can be improved as compared with the case where the second lamp unit  20  is not provided. 
     In the vehicle headlight  1  of the present embodiment, when the predetermined region  80  is determined by the region determination unit  55 , the control unit CO controls the second lamp unit  20  so that the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  overlapping with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  and not overlapping with the predetermined region  80  does not change from the light amount when the predetermined region  80  is not determined by the region determination unit  55 . Therefore, according to the vehicle headlight  1  of the present embodiment, the control of the second lamp unit  20  by the control unit CO can be simplified as compared with the case where the amount of the light changes. 
     When the predetermined region  80  is determined by the region determination unit  55 , the control unit CO may control the second lamp unit  20  so that the amount of light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  overlapping with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  and not overlapping with the predetermined region  80  increases as compared with the case where the predetermined region  80  is not determined by the region determination unit  55 . In this case, as compared with the case where the amount of the light does not increase, it is possible to increase the amount of the light from the second lamp unit  20  irradiated to at least a portion of the region that does not overlap with the predetermined region  80  among the first irradiation spots S 1   e  and S 1   f  in which the amount of the emitted light is reduced, and it is possible to further improve the forward visibility. When the predetermined region  80  is not determined by the region determination unit  55 , the amount of the light is preferably a total light amount obtained by adding the amount of the light from the first lamp unit  10  and the amount of the light from the second lamp unit irradiated to the second irradiation spot S 2  overlapping with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  and not overlapping with the predetermined region  80 . With such a configuration, it is possible to suppress the driver of the vehicle  100  from feeling uncomfortable about a region overlapping with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  and not overlapping with the predetermined region  80 . 
     When at least one first irradiation spot overlaps with at least two second irradiation spots as in the present embodiment, the control unit CO may control the second lamp unit  20  such that the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  closer to the predetermined region  80  among the second irradiation spots S 2  overlapping with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  and not overlapping with the predetermined region  80  is larger when the predetermined region  80  is not determined by the region determination unit  55 . 
     For example, as in the present embodiment, when a portion of the first irradiation spot S 1   f  in which the amount of the emitted light is reduced and a portion of the other first irradiation spot S 1   g  adjacent to the first irradiation spot S 1   f  overlap with each other, as illustrated in  FIG.  14   , the overlapping region SA overlapping with the other first irradiation spot S 1   g  among the first irradiation spots Sif in which the amount of the emitted light is reduced is irradiated with the light from the light emitting element  13   g  corresponding to the other first irradiation spot S 1   g . Here, in the irradiation spot irradiated with light, the intensity of light irradiated from the center side toward the outer edge side tends to decrease. Therefore, the intensity of the light from the light emitting element  13   g  corresponding to another first irradiation spot S 1   g  irradiated to the overlapping region SA tends to increase toward the predetermined region  80 . In the vehicle headlight as described above, among the second irradiation spots S 2  overlapping with the first irradiation spots S 1   e  and Sif in which the amount of the emitted light is reduced and not overlapping with the predetermined region  80 , the second irradiation spot S 2  closer to the predetermined region  80  has higher intensity of the emitted light. For this reason, for example, when second irradiation spot S 2  overlapping with the first irradiation spot Sif in which the amount of the emitted light is reduced and not overlapping with the predetermined region  80  overlaps with the overlapping region SA, the light intensity in the overlapping region SA can be made uniform, and the driver can be prevented from feeling uncomfortable about the overlapping region SA. 
     In addition, in the vehicle headlight  1  of the present embodiment, when the predetermined region  80  is not determined by the region determination unit  55 , the control unit CO controls the first lamp unit  10  and the second lamp unit  20  so that light is emitted from the first lamp unit  10  and the second lamp unit  20 . Therefore, in this case, the light distribution pattern PH of the high beam is formed by the light including the light emitted from the first lamp unit  10  and the light emitted from the second lamp unit. As described above, at least one first irradiation spot overlaps with at least one second irradiation spot. Therefore, the region irradiated with the light emitted from the first lamp unit  10  and the region irradiated with the light emitted from the second lamp unit  20  can overlap with each other. Therefore, according to the vehicle headlight  1  of the present embodiment, the degree of freedom of the light intensity distribution in the formed light distribution pattern PH of the high beam can be improved as compared with the case where the light from the second lamp unit  20  is not emitted in the above case. In addition, according to the vehicle headlight  1  of the present embodiment, the amount of light emitted from the light emitting element  23  can be reduced or the number of the light emitting elements  23  can be reduced as compared with the case where the light distribution pattern PH of the high beam is formed only by the second lamp unit  20 . Therefore, the heat generated in the light emitting element  23  can be easily dispersed, and the light emitting element  23  can be suppressed from being overheated. 
     In addition, the vehicle headlight  1  of the present embodiment further includes the determination unit  50  that determines whether or not another vehicle is in a state of satisfying a predetermined requirement on the basis of information from the detection device  110 . This predetermined requirement is that the distance between the other vehicle and the vehicle  100  is less than the predetermined distance, and the region determination unit  55  determines the predetermined region  80  as described above when the determination unit  50  determines that the other vehicle satisfies the predetermined requirement, and the first lamp unit  10  and the second lamp unit  20  are controlled by the control unit CO as described above. When the distance between the other vehicle and the vehicle  100  increases, dazzling of an occupant of the other vehicle tends to be less likely to occur. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress a change in the light distribution pattern PH of the high beam when dazzling of an occupant of another vehicle is unlikely to occur. Note that the region determination unit  55  may determine the predetermined region  80  as described above when a signal indicating detection of another vehicle is input from the detection device  110  regardless of the determination of the determination unit  50 , and the vehicle headlight  1  may not include the determination unit  50 . In this case, for example, when detecting another vehicle, the detection device  110  directly outputs a signal indicating detection of the other vehicle and a signal indicating a state of the other vehicle to the region determination unit  55 . 
     Second Embodiment 
     Next, a second embodiment as a first aspect of the present invention will be described in detail. Note that the same or equivalent components as those of the first embodiment are denoted by the same reference numerals and redundant description is omitted unless otherwise specified. 
     The vehicle headlight  1  of the present embodiment is mainly different from the vehicle headlight  1  of the first embodiment in that a light distribution pattern PH of a high beam is formed by light emitted from a first lamp unit  10  and light emitted from a third lamp unit  30 . Therefore, the operation of the vehicle headlight  1  of the present embodiment is different from the operation of the vehicle headlight  1  of the first embodiment. Although the control flowchart of the control unit in the present embodiment is the same as that in the first embodiment, the operation of the control unit CO in steps SP 15  and SP 16  is different. Therefore, steps SP 15  and SP 16  will be described, and description of the other steps SP 11  to SP 14  and SP 17  will be omitted. 
     (Step SP 15 ) 
     In step SP 15  of the present embodiment, the control unit CO controls the lamp units  10 ,  20   30 , and  20  so that light is emitted from the first lamp unit  10  and the third lamp unit  30  and light is not emitted from the second lamp unit so that a high beam is emitted from the vehicle headlight  1 . Specifically, the control unit CO outputs a predetermined signal to the power supply circuit  60  to cause the power supply circuit  60  to supply predetermined power to all the light emitting elements  13   a  to  13   h , stop the supply of power to all the light emitting elements  23 , and supply predetermined power to the light emitting element  32   a . Then, the control unit CO returns the control flow to step SP 11 . Therefore, the first lamp unit  10  emits light similar to that in step SP 15  of the first embodiment, the third lamp unit  30  emits light similar to that in step SP 15  of the first embodiment, and the light from the second lamp unit  20  is not emitted. Therefore, a high-beam light distribution pattern having the same outer shape as the high-beam light distribution pattern PH illustrated in  FIG.  11    is formed. Note that the light intensity distribution in the region overlapping with the region  70  in the light distribution pattern of the high beam is different from the light intensity distribution in the region overlapping with the region  70  in the light distribution pattern PH of the high beam illustrated in  FIG.  11   . 
     (Step SP 16 ) 
     In step SP 16  of the present embodiment, for example, in a case where the predetermined region  80  illustrated in  FIGS.  13  and  14    is formed by the region determination unit  55 , the control unit CO controls the plurality of light emitting elements  13   a  to  13   h  of the first lamp unit  10  similarly to the first embodiment. Therefore, the control unit CO controls the light emitting elements  13   e  and  13   f  so that the amount of the light emitted from the light emitting elements  13   e  and  13   e  corresponding to the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  is smaller than the light amount when a high beam is emitted. In addition, the control unit CO controls the light emitting elements  13   a  to  13   d ,  13   g , and  13   h  such that the amount of light emitted from the light emitting elements  13   a  to  13   d ,  13   g , and  13   h  corresponding to the first irradiation spots S 1   a  to S 1   d , S 1   g , and S 1   h  not overlapping with the predetermined region  80  becomes the amount of light when a high beam is emitted. In the present embodiment, the amount of light emitted from the light emitting elements  13   e  and  13   f  is zero. 
     Here, in the present embodiment, when a high beam is emitted, the light from the second lamp unit  20  is not emitted. The control unit CO controls the light emitting element  23  such that the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  overlapping with the predetermined region  80  becomes zero similarly to the case of emitting the high beam. Further, the control unit CO controls the light emitting element  23  so that light is emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  hatched in  FIG.  14   . Further, the control unit CO controls the light emitting element  23  so that the amount of the light emitted from the light emitting element  23  corresponding to the second irradiation spot S 2  not overlapping with the first irradiation spots S 1   e  and S 1   f  overlapping with the predetermined region  80  becomes zero similarly to the case of emitting the high beam. Specifically, the control unit CO outputs a control signal to the power supply circuit  60  such that the amount of light emitted from each light emitting element  23  becomes as described above, and the power supplied to each light emitting element  23  is adjusted by the driver of the power supply circuit  60 . In the present embodiment, the control unit CO controls the light emitting element  23  corresponding to the hatched second irradiation spot S 2  so that the amount of the light from the light emitting element  23  corresponding to the hatched second irradiation spot S 2  becomes the same as the amount of the light from the first lamp unit  10  irradiated to the second irradiation spot S 2  when a high beam is emitted. 
     Further, similarly to the first embodiment, the control unit CO controls the third lamp unit  30  so that light having the same specific light distribution pattern as the light distribution pattern of the light emitted from the third lamp unit  30  when emitting the high beam is emitted regardless of the predetermined region  80 . 
     As described above, the first lamp unit  10 , the second lamp unit  20 , and the third lamp unit  30  are controlled by the control unit CO so that a light distribution pattern having the same outer shape as the light distribution pattern  200  illustrated in  FIG.  15    and having the light reduction region  81  overlapping with the front window  91  as the visual recognition portion of the other vehicle  90  while the light amount is reduced as compared with the case of emitting the high beam is formed. The light intensity distribution in this light distribution pattern is different from the light distribution pattern  200  illustrated in  FIG.  15   . 
     In the vehicle headlight  1  of the present embodiment, similarly to the first embodiment, the amount of the light emitted from the first lamp unit  10  and irradiated on the visual recognition portion of the other vehicle  90  is reduced, and the amount of the light emitted from the second lamp unit  20  and irradiated on the visual recognition portion of the other vehicle  90  is reduced. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress dazzling of the occupant of the other vehicle  90 . In addition, in the vehicle headlight  1  of the present embodiment, similarly to the first embodiment, the second irradiation spot S 2  overlapping with the first irradiation spots S 1   e  and S 1   f  in which the amount of the emitted light is reduced and not overlapping with the predetermined region  80  is irradiated with light. Therefore, at least a portion of the region that does not overlap with the predetermined region  80  among the first irradiation spots S 1   e  and S 1   f  in which the amount of the emitted light is reduced can be irradiated with the light from the second lamp unit  20 . Therefore, according to the vehicle headlight  1  of the present embodiment, similarly to the first embodiment, the forward visibility can be improved as compared with the case where the second lamp unit  20  is not provided. 
     Although the first aspect of the present invention has been described by taking the first and second embodiments as an example, the first aspect of the present invention is not limited thereto. 
     For example, in the first and second embodiments, the first lamp unit  10  has been described by taking as an example the first lamp unit  10  that emits light from the plurality of light emitting elements  13   a  to  13   h  such that the first irradiation spots S 1   a  to S 1   h  irradiated with the light from the light emitting elements  13   a  to  13   h  are arranged in a line in the horizontal direction. However, the first lamp unit may emit light from the plurality of light emitting elements such that the first irradiation spots are arranged at least in the horizontal direction. For example, the first lamp unit may emit light from a plurality of light emitting elements so that the first irradiation spots are arranged vertically and horizontally, or may emit light from a plurality of light emitting elements so that the first irradiation spots are arranged in a plurality of rows in the horizontal direction. Examples of the configuration of such a first lamp unit include a configuration including a plurality of light emitting elements in which light distribution pattern forming units are arranged in a matrix in the first embodiment. 
     In the first and second embodiments, the second lamp unit  20  including the plurality of light emitting elements  23  capable of individually changing the amount of the emitted light and emitting the light from the plurality of light emitting elements  23  such that the second irradiation spots irradiated with the light from the respective light emitting elements  23  are arranged in a matrix has been described as an example. However, the second lamp unit  20  may have a configuration as illustrated in  FIG.  16   . 
       FIG.  16    is a cross-sectional view along a vertical direction schematically illustrating a second lamp unit according to a modification. As illustrated in  FIG.  16   , the second lamp unit  20  of the present modification is mainly different from the first lamp unit  10  of the above embodiment in that a light source  41 , a reflector  42 , a reflection device  43 , and a light absorbing plate  45  are provided as main components instead of the light distribution pattern forming unit  12 . 
     The light source  41  is a light emitting element that emits light. In the present modification, the light source  41  is disposed to emit light forward. Examples of the light source  41  include LEDs. 
     The reflector  42  is configured to reflect light emitted from the light source  41  by a reflecting surface  42   r  and irradiate a reflection control surface of the reflection device  43  described later with the light. In the present modification, the reflector  42  is a curved plate-like member, and is disposed so as to cover the light source  41  from the front side. A surface of the reflector  42  on the light source  41  side is the reflecting surface  42   r . The reflecting surface  42   r  is curved so as to be concave on the side opposite to the light source  41  side, and is configured, for example, to condense the light emitted from the light source  41  based on a spheroidal curved surface and irradiate the reflection control surface with the light. 
     The reflection device  43  of the present modification is a so-called digital mirror device (DMD), has a reflection control surface  43   r  that reflects incident light, and is configured to be able to form a predetermined light distribution pattern by the light reflected by the reflection control surface  43   r . The reflection device  43  is disposed above the light source  41  and behind the reflector  42  such that the reflection control surface  43   r  faces the front side. The reflection control surface  43   r  is irradiated with light emitted from the light source  41  and reflected by the reflector  42 . The reflection control surface  43   r  includes reflection surfaces of a plurality of reflective elements arranged in a matrix, and these reflective elements are supported on the substrate so as to be individually tiltable. The plurality of reflective elements can be individually switched between a first tilted state in which light from the reflector  42  is reflected toward the projection lens  15  and a second tilted state in which light from the reflector  42  is reflected toward the light absorbing plate  45  described later. Such a reflection device  43  can form a predetermined light distribution pattern by the light from the reflection control surface  43   r  toward the projection lens  15  by controlling the tilted state of the reflective element. In addition, by controlling the tilted state of these reflective elements over time, the light intensity distribution of a predetermined light distribution pattern can be set to a desired intensity distribution. That is, it can be understood that the plurality of reflective elements of the reflection device  43  are arranged in a matrix in which the amount of light emitted in the direction toward the projection lens  15  can be individually changed, and the reflection device  43  forms a predetermined light distribution pattern according to the amount of light emitted from the reflection surfaces of the plurality of reflective elements. Further, irradiation spots irradiated with light emitted from the respective reflective elements of the reflection device  43  in a direction toward the projection lens  15  are arranged in a matrix. 
     The light absorbing plate  45  is a plate-like member having a light absorbing property, and is configured to convert most of incident light into heat. In the present modification, the light absorbing plate  45  is disposed in front of and above the reflection device  43 , and light traveling from the reflection control surface  43   r  toward the light absorbing plate  45  enters the light absorbing plate  45 , and most of the light is converted into heat. Examples of the light absorbing plate  45  include a plate-like member made of metal such as aluminum and having a surface subjected to black alumite processing or the like. 
     Even with such a configuration of the second lamp unit  20 , similarly to the first and second embodiments, it is possible to improve the forward visibility while suppressing dazzling of the occupant of the other vehicle. Although not described, the light distribution pattern forming unit may be, for example, a liquid crystal on silicon (LCOS) or a diffraction grating that diffracts incident light to emit light of a predetermined light distribution pattern. Further, the first lamp unit  10  may have such a configuration. 
     In the first and second embodiments, the vehicle headlight  1  including the third lamp unit  30  has been described as an example. However, the vehicle headlight  1  may not include the third lamp unit  30 . The configuration of the third lamp unit  30  is not particularly limited. The third lamp unit  30  may be, for example, a parabolic lamp or a direct lens lamp, or may have a configuration in which the light distribution pattern of emitted light cannot be changed. In the above embodiment, the low beam is formed by the light emitted from the second lamp unit  20  and the light emitted from the third lamp unit  30 . However, the low beam may be formed only by the light emitted from the third lamp unit  30 . 
     In the first and second embodiments, the lamp units  10 ,  20 , and  30  each including the housings  16 ,  26 , and  36  have been described as an example. However, these lamp units  10 ,  20 , and  30  may share one housing, and other members different from the housings of the respective lamp units  10 ,  20 , and  30  may be accommodated in a lamp chamber in one housing. 
     Third Embodiment 
     Next, a third embodiment as a second aspect of the present invention will be described. Note that the same or equivalent components as those of the first embodiment are denoted by the same reference numerals and redundant description is omitted unless otherwise specified. 
       FIG.  17    is a plan view conceptually illustrating a vehicle including a vehicle headlight of the present embodiment. As illustrated in  FIG.  17   , the vehicle headlight  1  of the present embodiment is different from the vehicle headlight  1  of the first embodiment mainly in that it does not include the region determination unit  55 , includes a memory ME separate from the control unit CO, and does not include the first lamp unit  10  in each lamp unit  5 . 
     When detecting another vehicle, the detection device  110  of the present embodiment outputs a signal indicating detection of the other vehicle and a signal indicating a state of the other vehicle to the control unit CO via the determination unit  50 . Note that the detection device  110  may directly output these signals to the control unit CO. 
     When the other vehicle satisfies the predetermined requirement, the determination unit  50  of the present embodiment outputs, to the control unit CO, a signal indicating the distance from the vehicle  100  to the other vehicle and a signal indicating the position of the other vehicle with respect to the vehicle  100  as signals indicating the state of the other vehicle. In addition, the determination unit  50  stores the information indicating the distance and the position in the memory ME to be described later. These pieces of information stored in the memory ME are rewritten each time the information is stored. In addition, the determination unit  50  does not output a signal to the control unit CO when the other vehicle does not satisfy the predetermined requirement or when a signal is not input from the detection device  110  to the determination unit  50 . 
     The memory ME is configured to store information and read the stored information. The memory ME is, for example, a non-transitory recording medium, and is preferably a semiconductor recording medium such as a random access memory (RAM) or a read only memory (ROM), but may include a recording medium of any format such as an optical recording medium or a magnetic recording medium. Note that the “non-transitory” recording medium includes all computer-readable recording media except for a transitory propagating signal, and does not exclude a volatile recording medium. 
     The memory ME stores a table in which information on the light distribution pattern formed by the light emitted from the second lamp unit  20  is associated with the state of the other vehicle detected by the detection device  110 . Examples of the information on the light distribution pattern formed by the light emitted from the first lamp unit  10  include information on power supplied to each light emitting element  23  of the light distribution pattern forming unit  22 . Examples of the information on the power supplied to each light emitting element  23  include information on the power supplied to each light emitting element  23  when a light distribution pattern of a low beam described later is formed, when a light distribution pattern of a high beam is formed, when a light distribution pattern corresponding to another vehicle is formed, and when a light distribution pattern corresponding to another vehicle is changed to a light distribution pattern of a high beam. In addition, examples of the state of the other vehicle detected by the detection device  110  include the distance from the vehicle  100  to the other vehicle, the position of the other vehicle with respect to the vehicle  100 , and the like. The memory ME also stores information on predetermined power supplied to the light emitting element  32   a  of the third lamp unit  30  and a reference value. The reference value is a value that is referred to by the control unit CO and rewritten by the control unit CO in the control of the second lamp unit  20  and the third lamp unit  30  to be described later. In the present embodiment, the reference value is either zero or 1, and the initial value is zero. 
     In the present embodiment, when the signal indicating the emission of the low beam is input from the light switch  120 , the control unit CO refers to the information stored in the memory ME, and outputs a signal based on the power supplied to each light emitting element  23  in the light distribution pattern of the low beam and the predetermined power supplied to the light emitting element  32   a  to the power supply circuit  60 . As a result, power supplied to each light emitting element  23  is adjusted by the driver of the power supply circuit  60 , and predetermined power is supplied to the light emitting element  32   a . Then, light that becomes a low beam is emitted from the vehicle headlight  1 . The light distribution pattern PL of the low beam in the present embodiment is the same as the light distribution pattern PL of the low beam in the first embodiment. 
     In the present embodiment, a light distribution pattern of a high beam is formed by the light emitted from the second lamp unit  20  and the light emitted from the third lamp unit  30 . When the signal indicating the emission of the high beam is input from the light switch  120 , the control unit CO refers to the information stored in the memory ME, and outputs a signal based on the power supplied to each light emitting element  23  in the light distribution pattern of the high beam and the predetermined power supplied to the light emitting element  32   a  to the power supply circuit  60 . As a result, power supplied to each light emitting element  23  is adjusted by the driver of the power supply circuit  60 , and predetermined power is supplied to the light emitting element  32   a . Then, light that becomes a high beam is emitted from the vehicle headlight  1 . In the present embodiment, the light emitted from the third lamp unit  30  is the same as the light emitted from the second lamp unit  20  when a low beam is emitted. 
       FIG.  18    is a diagram illustrating a light distribution pattern of a high beam in the present embodiment. In  FIG.  18   , S indicates a horizontal line, V indicates a vertical line passing through the center of the vehicle  100  in the horizontal direction, and a light distribution pattern PH of a high beam formed on a virtual vertical screen arranged 25 meters ahead of the vehicle  100  is indicated by a thick line. In  FIG.  18   , a region  70  that can be irradiated with light from the second lamp unit  20  is indicated by a broken line. In the present embodiment, the outer shape of the region  70  is a rectangle elongated in the horizontal direction similarly to the outer shape of the region  70  in the first embodiment. However, the region  70  of the present embodiment is expanded to the right side, the left side, and the upper side from the region  70  of the first embodiment. That is, the light distribution pattern forming unit  22  and the projection lens  25  of the second lamp unit  20  are adjusted in such a manner. The hot zone HZH, which is a region having the highest light intensity in the light distribution pattern PH of the high beam, is located on or near the intersection of the horizontal line S and the vertical line V, and overlaps with the region  70 . In addition, the light distribution pattern PH of the high beam is substantially symmetrical, and the center of the light distribution pattern PH of the high beam in the horizontal direction is located on or near the vertical line V. Although not particularly illustrated, the hot zone HZL in the light distribution pattern PL of the low beam is included in the overlapping region  71  overlapping with the region  70  in the light distribution pattern PL of the low beam similarly to the first embodiment. 
     In the present embodiment, when a high beam is emitted from the vehicle headlight  1 , light is emitted from all the light emitting elements  23  in the second lamp unit  20 . Therefore, the region  70  is irradiated with the light from the light emitting element  23 . The light intensity distribution in the region overlapping with the region  70  in the light distribution pattern PH of the high beam is, for example, a distribution in which the intensity decreases as the distance from the hot zone HZH increases. In other words, the power supplied to each light emitting element  23  is adjusted by the control unit CO, and the amount of the light emitted from each light emitting element  23  is adjusted so that the intensity of the light in the region  70  has such a distribution. When light is emitted from the second lamp unit  20  and the third lamp unit  30  in this manner, a high beam is emitted from the vehicle headlight  1 . In the present embodiment, the light distribution pattern of the light emitted from the vehicle headlight  1  is switched between the light distribution pattern of the high beam and the light distribution pattern corresponding to the other vehicle in response to the detection of the other vehicle by the detection device  110 . 
     Next, an operation in which a light distribution pattern of light emitted from the vehicle headlight  1  of the present embodiment is switched between a light distribution pattern of a high beam and a light distribution pattern corresponding to another vehicle will be described.  FIG.  19    is a diagram illustrating an example of a control flowchart of the control unit CO according to the present embodiment. As illustrated in  FIG.  19   , the control flow of the present embodiment includes steps SP 21  to SP 24 . 
     (Step SP 21 ) 
     Emission of a high beam is selected by the light switch  120 , and a signal indicating emission of a high beam is input from the light switch  120  to the control unit CO. In  FIG.  19   , this state is a start state. The reference value stored in the memory ME is zero as an initial value. 
     In this step, the control unit CO determines whether or not another vehicle is detected by the detection device  110  and the other vehicle satisfies a predetermined requirement based on the signal input from the determination unit  50 . As described above, when detecting another vehicle, the detection device  110  outputs a signal indicating detection of the other vehicle to the control unit CO via the determination unit  50 . When the other vehicle detected by the detection device  110  satisfies the predetermined requirement, the determination unit  50  outputs, to the control unit CO, a signal indicating the distance from the vehicle  100  to the other vehicle and a signal indicating the position of the other vehicle with respect to the vehicle  100  as signals indicating the state of the other vehicle. Therefore, when the signal indicating the detection of the other vehicle and the signal indicating the state of the other vehicle are input from the determination unit  50 , the control unit CO determines that the other vehicle satisfies the predetermined requirement, and advances the control flow to step SP 22 . On the other hand, when the signal indicating the state of the other vehicle is not input from the determination unit  50 , the control unit CO determines that the other vehicle does not satisfy the predetermined requirement, and advances the control flow to step SP 23 . When no other vehicle is detected by the detection device  110 , a signal indicating the state of the other vehicle is not input to the determination unit  50 , and a signal indicating the detection of the other vehicle is not input to the control unit CO. Therefore, also in such a case, the control flow proceeds to step SP 13 . 
     (Step SP 22 ) 
     In this step, the control unit CO controls the second lamp unit  20  and the third lamp unit  30  so that a light distribution pattern of light emitted from the vehicle headlight  1  becomes a light distribution pattern corresponding to another vehicle detected by the detection device  110 . Specifically, the control unit CO refers to the table stored in the memory ME based on a signal indicating the distance from the vehicle  100  to another vehicle and a signal indicating the position of the other vehicle with respect to the vehicle  100 . Then, the control unit CO outputs, to the power supply circuit  60 , a signal based on the power supplied to each light emitting element  23  in the light distribution pattern according to the information on the state of the other vehicle and the predetermined power supplied to the light emitting element  32   a . As a result, the driver of the power supply circuit  60  adjusts the power supplied to each light emitting element  23  so as to generate light of a light distribution pattern corresponding to the information on the state of another vehicle, and supplies predetermined power to the light emitting element  32   a . As a result, light having the light distribution pattern is emitted from the vehicle headlight  1 . Then, the control unit CO stores the distance from the vehicle  100  to the other vehicle and the information on the position of the other vehicle with respect to the vehicle  100  in the memory ME, rewrites the reference value stored in the memory ME to 1, and advances the control flow to step SP 24 . Therefore, when the reference value is 1, it can be understood that the vehicle headlight  1  is in a state of emitting light of a light distribution pattern corresponding to another vehicle, and when the reference value is zero, it can be understood that the vehicle headlight  1  is in a state of not emitting light of a light distribution pattern corresponding to another vehicle. 
       FIG.  20    is a diagram illustrating an example of a light distribution pattern of light emitted when a preceding vehicle is detected as another vehicle by the detection device  110 . In  FIG.  20   , S indicates a horizontal line, V indicates a vertical line passing through the center of the vehicle  100  in the horizontal direction, and a light distribution pattern  300  formed on a virtual vertical screen arranged 25 meters ahead of the vehicle  100  is indicated by a thick line. 
     In the present embodiment, the shape of the light distribution pattern  300  is the same as the shape of the light distribution pattern PH of the high beam illustrated in  FIG.  18   . However, the amount of the light from the second lamp unit  20  in a predetermined region  310  of the light distribution pattern  300  is smaller than the amount of the light from the second lamp unit  20  irradiated on the region corresponding to the predetermined region  310  in the high-beam light distribution pattern PH, and the intensity of the light in the predetermined region  310  is lower than a predetermined reference intensity. In the present embodiment, the intensity of light in the predetermined region  310  is substantially constant. Note that the predetermined region  310  may be a region that is not irradiated with light. As described above, in the predetermined region  310 , the amount of the light from the second lamp unit  20  is reduced as compared with the case where the determination unit  50  determines that the other vehicle does not satisfy the predetermined requirement. On the other hand, the light intensity distribution in the region other than the predetermined region  310  in the light distribution pattern  300  is substantially the same as the light intensity distribution in the region other than the region corresponding to the predetermined region  310  in the light distribution pattern PH. Therefore, the region other than the predetermined region  310  in the light distribution pattern  300  is a region where the amount of the light from the second lamp unit  20  is not reduced, and is brighter than the predetermined region  310 . The light distribution pattern  300  is a light distribution pattern in which the amount of light from the second lamp unit  20  in the predetermined region  310  in the high-beam light distribution pattern PH is reduced. 
     The predetermined region  310  is located in the region  70  that can be irradiated with the light from the second lamp unit  20 , and overlaps with a visual recognition portion for a driver of another vehicle detected by the detection device  110  to visually recognize the outside of the vehicle. The predetermined region  310  preferably overlaps with the entire visual recognition portion of another vehicle. In the example illustrated in  FIG.  20   , the predetermined region  310  has a rectangular shape including the entire other vehicle  90  detected by the detection device  110 , and a side mirror and a rear-view mirror as visual recognition portions are located in the predetermined region  310 . 
     Next, step SP 23  indicating the operation of the control unit CO when the other vehicle detected by the detection device  110  does not satisfy the predetermined requirement will be described. 
     (Step SP 23 ) 
     In this step, the control unit CO controls the second lamp unit  20  and the third lamp unit  30  so that a high beam is emitted from the vehicle headlight  1 . Note that the control of the second lamp unit  20  by the control unit CO differs depending on whether the reference value stored in the memory ME is zero or 1. First, a case where the reference value stored in the memory ME is zero, which is an initial value, will be described. 
     The control unit CO refers to the reference value stored in the memory ME, and refers to the information on the light distribution pattern of the high beam stored in the memory ME when the reference value is zero. Then, as described above, the control unit CO outputs a signal based on the power supplied to each light emitting element  23  in the light distribution pattern of the high beam and the predetermined power supplied to the light emitting element  32   a  to the power supply circuit  60 . As a result, the driver of the power supply circuit  60  adjusts the power supplied to each light emitting element  23  so as to generate the light having the light distribution pattern PH of the high beam, and the light having the light distribution pattern PH of the high beam is emitted from the vehicle headlight  1 . Then, the control unit CO advances the control flow to step SP 24 . 
     On the other hand, a case where the reference value is 1 is a case where the vehicle headlight  1  emits light of the light distribution pattern  300  corresponding to another vehicle as described above. Therefore, this is a state in which the vehicle headlight  1  emits light of the light distribution pattern  300  corresponding to the other vehicle even though the other vehicle detected by the detection device  110  does not satisfy the predetermined requirement or the other vehicle is not detected by the detection device  110 . Examples of such a state include a case where another vehicle detected by the detection device  110  is not detected. In a case where the other vehicle is a preceding vehicle, for example, when the preceding vehicle and the vehicle  100  are traveling on an uphill, the preceding vehicle exceeds the top of the uphill, and the preceding vehicle is not detected by the detection device  110 . In a case where the other vehicle is an oncoming vehicle, for example, there is a case where the oncoming vehicle is hidden behind a building or the like due to the oncoming vehicle entering a parking lot or the like, and the oncoming vehicle is not detected by the detection device  110 . 
     As described above, when the other vehicle satisfies the predetermined requirement, the determination unit  50  stores information indicating the distance from the vehicle  100  to the other vehicle and the position of the other vehicle with respect to the vehicle  100  in the memory ME. Therefore, information indicating the state of the other vehicle immediately before the other vehicle no longer satisfies the predetermined requirement is stored in the memory ME. The control unit CO refers to the reference value stored in the memory ME, and when the reference value is 1, refers to the table stored in the memory ME based on the information indicating the state of the other vehicle stored in the memory ME. Then, the control unit CO outputs, to the power supply circuit  60 , a signal based on the power supplied to each light emitting element  23  when the light distribution pattern  300  corresponding to the information indicating the state of the other vehicle is changed to the high-beam light distribution pattern PH. The control unit CO also outputs a signal based on predetermined power supplied to the light emitting element  32   a  to the power supply circuit  60 . As a result, the power supplied to each light emitting element  23  is adjusted by the driver of the power supply circuit  60  so that the light distribution pattern  300  according to the information on another vehicle changes to the light distribution pattern PH of the high beam, and predetermined power is supplied to the light emitting element  32   a . As a result, the light distribution pattern  300  corresponding to another vehicle changes to the high-beam light distribution pattern PH, and light that becomes the high-beam light distribution pattern PH is emitted from the vehicle headlight  1 . Therefore, it can be understood that the vehicle headlight  1  is switched from the second state to the first state when the state of emitting the light of the light distribution pattern PH of the high beam is the first state and the state of emitting the light of the light distribution pattern  300  corresponding to another vehicle is the second state. Then, the control unit CO rewrites the reference value stored in the memory ME to zero, and advances the control flow to step SP 24 . 
       FIG.  21    is a view for explaining an example of a state in which the light distribution pattern  300  according to another vehicle in the present embodiment changes, and is an enlarged view of a predetermined region  310  and the vicinity thereof in the light distribution pattern  300 . Note that the state illustrated in  FIG.  21    is a state in which, for example, when the vehicle  100  that emits light having the light distribution pattern  300  illustrated in  FIG.  20    and a preceding vehicle are traveling on an uphill, the preceding vehicle exceeds the top of the uphill, and the preceding vehicle is no longer detected by the detection device  110 . In the present embodiment, first, the amount of light from the second lamp unit  20  in the predetermined region  310  is increased over time. Then, as illustrated in  FIG.  21   , the light amount in the region  311  that is a partial region of the predetermined region  310  is returned to the light amount in the region corresponding to the region  311  in the high-beam light distribution pattern PH illustrated in  FIG.  18   . That is, the region  311  can be understood as a region returned to the light amount in the first state in which the light distribution pattern PH of the high beam is emitted from the vehicle headlight  1 . In the present embodiment, the amount of the light from the second lamp unit  20  in the predetermined region  310  is increased over time so that the intensity of the light from the second lamp unit  20  decreases upward from the lower edge DE of the predetermined region  310 . In addition, the region  311  returned to the light amount in the first state is a rectangular region extending along the lower edge DE of the predetermined region  310 . The region  311  may be in contact with the lower edge DE, and the shape of the region  311  is not particularly limited. Furthermore, in  FIG.  21   , the region  311  is hatched for easy understanding. 
     Next, the amount of the light from the second lamp unit  20  is further increased over time in a region other than the region  311  returned to the light amount in the first state in the predetermined region  310  so that the region  311  returned to the light amount in the first state expands upward. In the present embodiment, the amount of the light from the second lamp unit  20  is increased over time such that the intensity of the light from the second lamp unit  20  decreases as the distance from the region  311  increases. For this reason, while a brighter state is maintained in a region close to the region  311  than in a region far from the region  311 , both regions become brighter over time. Then, the region  311  is returned to the light amount in the first state in order from the region close to the region  311 , and the region  311  expands. Then, the entire predetermined region  310  becomes the region  311  returned to the light amount in the first state, so that the light distribution pattern of the light emitted from the vehicle headlight  1  becomes the high-beam light distribution pattern PH. 
     Note that the region  311  returned to the light amount in the first state may expand upward from the lower edge DE of the predetermined region  310  over time. For example, when the amount of light from the second lamp unit  20  is increased over time in a region other than the region  311  in the predetermined region  310 , the amount of light may increase in the entire region, or the amount of light may increase in a portion of the region. 
     As described above, in this step, when the vehicle headlight  1  is in the second state, the region  311  returned to the light amount in the first state expands over time, so that the region where the light amount has been reduced becomes smaller over time, and the region where the light amount has been reduced disappears, so that the vehicle headlight  1  is switched from the second state to the first state. 
     (Step SP 24 ) 
     In this step, the control unit CO determines whether or not a signal indicating emission of a high beam is input from the light switch  120 . When this signal is input to the control unit CO, the control unit CO returns the control flow to step SP 21 . On the other hand, in a case where this signal is not input to the control unit CO, the control unit CO outputs a predetermined signal to the power supply circuit  60 , causes the power supply circuit  60  to stop the supply of power to each light emitting element  23  and the supply of power to the light emitting element  32   a , does not emit light from the vehicle headlight  1 , and ends this control. 
     As described above, in the present embodiment, the state of the vehicle headlight  1  is switched between a state of emitting a high beam and a state of emitting light of a light distribution pattern corresponding to another vehicle according to whether another vehicle is in a state of satisfying a predetermined requirement. The control flow of the control unit CO is not limited to the control flow illustrated in  FIG.  19   . 
     Meanwhile, Patent Literature 2 described above describes that the state of a vehicle headlight is switched from a first state in which light having a predetermined light distribution pattern is emitted to a second state in which light having a light distribution pattern in which a light shielding region is formed in the predetermined light distribution pattern is emitted, but does not describe that the state is switched from the second state to the first state. For example, in a case where the state is instantaneously switched from the second state to the first state, the entire light shielding region is suddenly irradiated with light, and thus the driver may feel uncomfortable. 
     Therefore, the vehicle headlight  1  of the present embodiment includes the second lamp unit  20 . The second lamp unit  20  includes the plurality of light emitting elements  23  that can individually change the amount of light emitted and are arranged in a matrix, and emits light having a light distribution pattern corresponding to the amount of light emitted from the plurality of light emitting elements  23 . In addition, the vehicle headlight  1  of the present embodiment can be switched between a first state in which a high beam that is light of a predetermined light distribution pattern is emitted and a second state in which light of the light distribution pattern  300  in which the light amount of the predetermined region  310  in the light distribution pattern PH of the high beam is reduced is emitted. In the vehicle headlight  1  of the present embodiment, the predetermined region  310  overlaps with a visual recognition portion for a driver of another vehicle to view the outside of the vehicle. Therefore, according to the vehicle headlight  1  of the present embodiment, switching from the first state to the second state can suppress dazzling of an occupant of another vehicle. In addition, in the vehicle headlight  1  of the present embodiment, when the state is switched from the first state to the second state, the amount of light in a partial region  311  of the predetermined region  310  is returned to the amount of light in the region  311  in the first state, and the region  311  expands over time. Therefore, in the vehicle headlight  1  of the present embodiment, the region  311  in the predetermined region  310  becomes bright, and the bright region  311  expands over time. In other words, the region where the amount of the light is reduced becomes smaller over time. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310  as compared with the case of instantaneously switching from the second state to the first state. 
     In the vehicle headlight  1  of the present embodiment, the region  311  expands upward from the lower edge DE of the predetermined region  310  over time. The object to which the driver pays attention includes, for example, a pedestrian, an obstacle, and the like on a road as well as other vehicles. In the vehicle headlight  1  of the present embodiment, when switching from the second state to the first state, it can be brightened from the side close to the road in the predetermined region  310 . Therefore, according to the vehicle headlight  1  of the present embodiment, for example, when a predetermined region overlaps with a pedestrian, an obstacle, or the like on a road at the time of switching from the second state to the first state, the pedestrian, the obstacle, or the like can be recognized by the driver more quickly. 
     In the vehicle headlight  1  of the present embodiment, when switching from the second state to the first state, in a region other than the region  311  in the predetermined region  310 , the amount of the light is increased over time such that the intensity of the light decreases as the distance from the region  311  increases. As described above, in the vehicle headlight  1  of the present embodiment, when the state is switched from the second state to the first state, the region  311  in the predetermined region  310  becomes bright, and the bright region  311  expands over time. Therefore, with the above configuration, it is possible to make the predetermined region  310  darker with increasing distance from the bright region, and to make the boundary between the bright region and the dark region inconspicuous. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     In addition, the vehicle headlight  1  of the present embodiment further includes the determination unit  50  that determines whether or not another vehicle is in a state of satisfying a predetermined requirement on the basis of information from the detection device  110 . The predetermined requirement is that the distance between the other vehicle and the vehicle  100  is less than the predetermined distance, and the control unit CO controls the second lamp unit  20  as described above when the determination unit  50  determines that the other vehicle satisfies the predetermined requirement. When the distance between the other vehicle and the vehicle  100  increases, dazzling of an occupant of the other vehicle tends to be less likely to occur. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress a change in the light distribution pattern PH of the high beam when dazzling of an occupant of another vehicle is unlikely to occur. Note that the control unit CO may control the second lamp unit  20  as described above when a signal indicating detection of another vehicle is input from the detection device  110  regardless of the determination of the determination unit  50 , and the vehicle headlight  1  may not include the determination unit  50 . In this case, for example, when detecting another vehicle, the detection device  110  directly outputs a signal indicating detection of the other vehicle and a signal indicating the state of the other vehicle to the control unit CO, and stores information indicating the state of the other vehicle in the memory ME. 
     Fourth Embodiment 
     Next, a fourth embodiment as a second aspect of the present invention will be described in detail. Note that the same or equivalent components as those of the third embodiment are denoted by the same reference numerals, and redundant description is omitted unless otherwise specified. The present embodiment is different from the third embodiment in the manner of changing the light amount in the predetermined region  310  when the state is switched from the second state to the first state.  FIG.  22    is a view for explaining an example of a state in which the light distribution pattern  200  according to another vehicle in the present embodiment changes, and is an enlarged view of a predetermined region  310  and the vicinity thereof in the light distribution pattern  300 . 
     In the present embodiment, similarly to the third embodiment, the amount of light from the second lamp unit  20  in the predetermined region  310  is increased over time. Then, as illustrated in  FIG.  22   , the light amount in the region  311  that is a partial region of the predetermined region  310  is returned to the light amount in the region corresponding to the region  311  in the high-beam light distribution pattern PH illustrated in  FIG.  18   . However, in the present embodiment, the amount of the light from the second lamp unit  20  in the predetermined region  310  is increased over time so that the intensity of the light from the second lamp unit  20  decreases downward from the upper edge UE of the predetermined region  310 . In addition, the region  311  returned to the light amount in the first state is a rectangular region extending along the upper edge UE of the predetermined region  310 . Note that the region  311  only needs to be in contact with the upper edge UE, and the shape of the region  311  is not particularly limited. Then, the amount of the light from the second lamp unit  20  is further increased over time in a region other than the region  311  returned to the light amount in the first state in the predetermined region  310  such that the region  311  returned to the light amount in the first state expands downward. In the present embodiment, similarly to the third embodiment, the amount of the light from the second lamp unit  20  is increased over time such that the intensity of the light from the second lamp unit  20  decreases as the distance from the region  311  increases. For this reason, while the state in which the region close to the region  311  is brighter than the region far from the region  311  is maintained, both regions become brighter over time. Then, the region  311  is returned to the light amount in the first state in order from the region close to the region  311 , and the region  311  expands. Then, the entire predetermined region  310  becomes the region  311  returned to the light amount in the first state, whereby the second state is switched to the first state. In  FIG.  22   , the region  311  is hatched for easy understanding. 
     Note that the region  311  returned to the light amount in the first state may expand downward from the upper edge UE of the predetermined region  310  as time passes. For example, when the amount of light from the second lamp unit  20  is increased over time in a region other than the region  311  in the predetermined region  310 , the amount of light may increase in the entire region, or the amount of light may increase in a portion of the region. 
     In the vehicle headlight  1  of the present embodiment, when switching from the second state to the first state, as in the third embodiment, the region  311  in the predetermined region  310  becomes bright, and the bright region  311  expands over time. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     In the present embodiment, when the state is switched from the second state to the first state, the region  311  expands from the upper edge UE of the predetermined region  310  toward the lower side over time, and thus becomes brighter from the upper side of the predetermined region  310 . Here, a sign is located above the road. Therefore, according to the vehicle headlight  1  of the present embodiment, for example, when the predetermined region  310  and the sign overlap with each other at the time of switching from the second state to the first state, the sign can be recognized by the driver more quickly. 
     In the vehicle headlight  1  of the present embodiment, as in the third embodiment, when the state is switched from the second state to the first state, in a region other than the region  311  in the predetermined region  310 , the light amount is increased over time such that the intensity of light decreases as the distance from the region  311  increases. Therefore, according to the vehicle headlight  1  of the present embodiment, similarly to the third embodiment, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     Fifth Embodiment 
     Next, a fifth embodiment as a second aspect of the present invention will be described in detail. Note that the same or equivalent components as those of the third embodiment are denoted by the same reference numerals, and redundant description is omitted unless otherwise specified. The present embodiment is different from the third embodiment in the manner of changing the light amount in the predetermined region  310  when the state is switched from the second state to the first state.  FIG.  23    is a view for explaining an example of a state in which the light distribution pattern  300  according to another vehicle in the present embodiment changes, and is an enlarged view of a predetermined region  310  and the vicinity thereof in the light distribution pattern  300 . 
     In the present embodiment, similarly to the third embodiment, the amount of light from the second lamp unit  20  in the predetermined region  310  is increased over time. Then, as illustrated in  FIG.  23   , the light amount in the region  311  that is a partial region of the predetermined region  310  is returned to the light amount in the region corresponding to the region  311  in the high-beam light distribution pattern PH illustrated in  FIG.  18   . However, in the present embodiment, the amount of the light from the second lamp unit  20  in the predetermined region  310  is increased over time so that the intensity of the light from the second lamp unit  20  decreases from the right edge RE of the predetermined region  310  toward the left side. In addition, the region  311  returned to the light amount in the first state is a rectangular region extending along the right edge RE of the predetermined region  310 . Note that the region  311  may be in contact with the right edge RE, and the shape of the region  311  is not particularly limited. Then, the amount of the light from the first lamp unit  10  is further increased over time in a region other than the region  311  returned to the light amount in the first state in the predetermined region  310  such that the region  311  returned to the light amount in the first state expands to the left side. In the present embodiment, similarly to the third embodiment, the amount of the light from the second lamp unit  20  is increased over time such that the intensity of the light from the second lamp unit  20  decreases as the distance from the region  311  increases. For this reason, while a brighter state is maintained in a region close to the region  311  than in a region far from the region  311 , both regions become brighter over time. Then, the region  311  is returned to the light amount in the first state in order from the region close to the region  311 , and the region  311  expands. Then, the entire predetermined region  310  becomes the region  311  returned to the light amount in the first state, whereby the second state is switched to the first state. In  FIG.  23   , the region  311  is hatched for easy understanding. 
     When the amount of the light from the second lamp unit  20  is increased over time in the region other than the region  311  in the predetermined region  310 , the light amount may increase in the entire region, or the light amount may increase in a portion of the region. 
     In the vehicle headlight  1  of the present embodiment, when switching from the second state to the first state, as in the third embodiment, the region  311  in the predetermined region  310  becomes brighter, and the brightened region  311  expands over time. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     In the vehicle headlight  1  of the present embodiment, as in the third embodiment, when switching from the second state to the first state, in a region other than the region  311  in the predetermined region  310 , the amount of the light is increased over time so that the intensity of the light decreases as the distance from the region  311  increases. Therefore, according to the vehicle headlight  1  of the present embodiment, similarly to the third embodiment, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     In the vehicle headlight  1  of the present embodiment, when switching from the second state to the first state, the region  311  expands from the right edge RE of the predetermined region  310  toward the left side over time, and thus, becomes bright from the right side of the predetermined region  310 . Therefore, the adjustment of the light emitted from the plurality of light emitting elements  23  can be simplified and the control of the plurality of light emitting elements  23  by the control unit CO can be simplified as compared with the case where the light is brighter from both sides in the horizontal direction of the predetermined region  310 . From the viewpoint of simplifying the control of the plurality of light emitting elements  23 , when the state is switched from the second state to the first state, the region  311  may expand from the edge on one side in the horizontal direction of the predetermined region  310  toward the other side over time. For example, the region  311  may expand from the left edge LE of the predetermined region  310  toward the right side over time. Further, as described above, in the configuration in which the region  311  expands from the edge on one side in the horizontal direction of the predetermined region  310  toward the other side over time, when the predetermined region  310  and the sign located on the shoulder side overlap with each other and the region  311  expands from the edge on the side where the sign is located in the horizontal direction, the driver can recognize the sign quickly. 
     In the present embodiment, the center of the predetermined region  310  in the horizontal direction is located on the left side of the vertical line V. As described above, since the center of the light distribution pattern PH of the high beam in the horizontal direction is located on or near the vertical line V, the center of the predetermined region  310  in the horizontal direction is shifted to the left from the center of the light distribution pattern PH of the high beam in the horizontal direction. Then, when the state is switched from the second state to the first state, the region  311  expands leftward from the right edge RE in the predetermined region  310 . Note that, although illustration is omitted, in the vehicle headlight  1  of the present embodiment, in a case where the center in the horizontal direction of the predetermined region  310  is shifted to the right from the center in the horizontal direction of the light distribution pattern PH of the high beam, when the state is switched from the second state to the first state, the region  311  expands from the left edge LE to the right in the predetermined region  310 . Therefore, it can be understood that the center of the predetermined region  310  is shifted to a predetermined side in the horizontal direction from the center in the horizontal direction of the light distribution pattern PH of the high beam, and the region  311  expands from the edge on the opposite side to the predetermined side in the horizontal direction of the predetermined region  310  toward the predetermined side over time. In the vehicle headlight  1  of the present embodiment having such a configuration, when the state is switched from the second state to the first state, it can be brightened from the side close to the vertical line V passing through the center of the vehicle  100  among both sides in the horizontal direction of the predetermined region  310 . Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310  as compared with the case where the brightness is brighter from the side farther from the vertical line V passing through the center of the vehicle  100  among both sides in the horizontal direction of the predetermined region  310 . 
     Sixth Embodiment 
     Next, a sixth embodiment as a second aspect of the present invention will be described in detail. Note that the same or equivalent components as those of the third embodiment are denoted by the same reference numerals, and redundant description is omitted unless otherwise specified. The present embodiment is different from the third embodiment in the manner of changing the light amount in the predetermined region  310  when the state is switched from the second state to the first state.  FIG.  24    is a view for explaining an example of a state in which the light distribution pattern  300  according to another vehicle in the present embodiment changes, and is an enlarged view of a predetermined region  310  and the vicinity thereof in the light distribution pattern  300 . 
     In the present embodiment, similarly to the third embodiment, the amount of light from the second lamp unit  20  in the predetermined region  310  is increased over time. Then, as illustrated in  FIG.  24   , the light amount in the region  311  that is a partial region of the predetermined region  310  is returned to the light amount in the region corresponding to the region  311  in the high-beam light distribution pattern PH illustrated in  FIG.  18   . However, in the present embodiment, the amount of the light from the second lamp unit  20  in the predetermined region  310  is increased over time so that the intensity of the light from the second lamp unit  20  decreases from the entire circumference of the outer peripheral edge including the upper, lower, left, and right edges UE, DE, LE, and RE of the predetermined region  310  toward the inside of the predetermined region  310 . The region  311  returned to the light amount in the first state is an annular region extending along the entire circumference of the outer peripheral edge of the predetermined region  310 . Note that the region  311  may be in contact with the entire circumference of the outer peripheral edge of the predetermined region  310 , and the shape of the region  311  is not particularly limited. Then, the amount of the light from the second lamp unit  20  is further increased over time in a region other than the region  311  returned to the light amount in the first state in the predetermined region  310  such that the region  311  returned to the light amount in the first state expands toward the inside of the predetermined region  310 . In the present embodiment, similarly to the third embodiment, the amount of the light from the second lamp unit  20  is increased over time such that the intensity of the light from the second lamp unit  20  decreases as the distance from the region  311  increases. For this reason, while the state in which the region close to the region  311  is brighter than the region far from the region  311  is maintained, both regions become brighter over time. Then, the region  311  is returned to the light amount in the first state in order from the region close to the region  311 , and the region  311  expands. Then, the entire predetermined region  310  becomes the region  311  returned to the light amount in the first state, whereby the second state is switched to the first state. In  FIG.  24   , the region  311  is hatched for easy understanding. 
     In the vehicle headlight  1  of the present embodiment, when switching from the second state to the first state, in the region  311 , the predetermined region  310  expands from the entire circumference of the outer peripheral edge toward the inner side of the predetermined region  310  over time. Therefore, as compared with the case where the region  311  expands from a portion of the outer peripheral edge of the predetermined region  310 , the predetermined region  310  can be brightened quickly. Therefore, a sign or the like overlapping with the predetermined region  310  can be recognized by the driver more quickly. In addition, as compared with a case where the region  311  extends from a portion of the outer peripheral edge of the predetermined region  310 , it is possible to suppress the driver from feeling uncomfortable and to give the driver a sense of security. Note that the region  311  returned to the light amount in the first state may expand from the entire circumference of the outer peripheral edge of the predetermined region  310  toward the inner side of the predetermined region  310  over time. For example, when the amount of light from the second lamp unit  20  is increased over time in a region other than the region  311  in the predetermined region  310 , the amount of light may increase in the entire region, or the amount of light may increase in a portion of the region. 
     In the vehicle headlight  1  of the present embodiment, when switching from the second state to the first state, as in the third embodiment, the region  311  in the predetermined region  310  becomes brighter, and the brightened region  311  expands over time. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     In the vehicle headlight  1  of the present embodiment, as in the third embodiment, when the state is switched from the second state to the first state, in a region other than the region  311  in the predetermined region  310 , the light amount is increased over time such that the intensity of light decreases as the distance from the region  311  increases. Therefore, according to the vehicle headlight  1  of the present embodiment, similarly to the third embodiment, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     Note that how the region  311  expands is not particularly limited. For example, the region  311  may expand from the left and right edges LE and RE of the predetermined region  310  toward the inside of the predetermined region  310 , or may expand from the upper and lower edges UE and DE of the predetermined region  310  toward the inside of the predetermined region  310 . Even if the region  311  expands in this manner, it is possible to suppress the driver from feeling uncomfortable about the change in brightness of the predetermined region  310  as in the third embodiment. 
     Seventh Embodiment 
     Next, a seventh embodiment as a second aspect of the present invention will be described in detail. Note that the same or equivalent components as those of the third embodiment are denoted by the same reference numerals, and redundant description is omitted unless otherwise specified. The present embodiment is different from the third embodiment in the manner of changing the light amount in the predetermined region  310  when the state is switched from the second state to the first state.  FIG.  25    is a view for explaining an example of a state in which the light distribution pattern  300  according to another vehicle in the present embodiment changes, and is an enlarged view of a predetermined region  310  and the vicinity thereof in the light distribution pattern  300 . 
     In the present embodiment, similarly to the third embodiment, the amount of light from the second lamp unit  20  in the predetermined region  310  is increased over time. Then, as illustrated in  FIG.  25   , the light amount in the region  311  that is a partial region of the predetermined region  310  is returned to the light amount in the region corresponding to the region  311  in the high-beam light distribution pattern PH illustrated in  FIG.  18   . However, in the present embodiment, the amount of the light from the second lamp unit  20  in the predetermined region  310  is increased over time such that the intensity of the light from the second lamp unit  20  decreases from the inner side of the predetermined region  310  toward the outer peripheral side of the predetermined region  310 . In addition, the region  311  returned to the light amount in the first state is a rectangular region located inside the outer peripheral edge of the predetermined region  310  and overlapping with the center of the predetermined region  310 . Note that the region  311  only needs to be separated from the outer peripheral edge of the predetermined region  310 , and the shape and position of the region  311  are not particularly limited. Then, the amount of the light from the second lamp unit  20  is further increased over time in a region other than the region  311  returned to the light amount in the first state in the predetermined region  310  such that the region  311  returned to the light amount in the first state expands toward the outer peripheral side of the predetermined region  310 . In the present embodiment, similarly to the third embodiment, the amount of the light from the second lamp unit  20  is increased over time such that the intensity of the light from the second lamp unit  20  decreases as the distance from the region  311  increases. For this reason, while the state in which the region close to the region  311  is brighter than the region far from the region  311  is maintained, both regions become brighter over time. Then, the region  311  is returned to the light amount in the first state in order from the region close to the region  311 , and the region  311  expands. Then, the entire predetermined region  310  becomes the region  311  returned to the light amount in the first state, whereby the second state is switched to the first state. In  FIG.  25   , the region  311  is hatched for easy understanding. 
     Note that the region  311  returned to the light amount in the first state may expand from the inner side of the predetermined region  310  toward the outer side of the predetermined region  310  over time. For example, when the amount of light from the second lamp unit  20  is increased over time in a region other than the region  311  in the predetermined region  310 , the amount of light may increase in the entire region, or the amount of light may increase in a portion of the region. 
     In the vehicle headlight  1  of the present embodiment, when switching from the second state to the first state, as in the third embodiment, the region  311  in the predetermined region  310  becomes brighter, and the brightened region  311  expands over time. Therefore, according to the vehicle headlight  1  of the present embodiment, it is possible to suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     In the vehicle headlight  1  of the present embodiment, as in the third embodiment, when the state is switched from the second state to the first state, in a region other than the region  311  in the predetermined region  310 , the light amount is increased over time such that the intensity of light decreases as the distance from the region  311  increases. Therefore, according to the vehicle headlight  1  of the present embodiment, similarly to the third embodiment, it is possible to further suppress the driver from feeling uncomfortable about the change in brightness in the predetermined region  310 . 
     In the present embodiment, the speed at which the region  311  expands downward is substantially the same as the speed at which the region  311  expands upward, but may be faster than the speed at which the region  311  expands upward. With such a configuration, when the state is switched from the second state to the first state, the lower side in the predetermined region  310  can be brighter than the upper side. Therefore, according to such a vehicle headlight, for example, when the predetermined region  310  overlaps with a pedestrian, an obstacle, or the like on the road at the time of switching from the second state to the first state, the pedestrian, the obstacle, or the like can be recognized by the driver more quickly. 
     Alternatively, the speed at which the region  311  expands upward may be faster than the speed at which the region  311  expands downward. With such a configuration, when the state is switched from the second state to the first state, the upper side in the predetermined region  310  can be brighter than the lower side. Therefore, according to such a vehicle headlight, for example, when the predetermined region  310  and the sign overlap with each other at the time of switching from the second state to the first state, the driver can recognize the sign more quickly. 
     In the present embodiment, the entire outer peripheral edge of the predetermined region  310  simultaneously coincides with the outer peripheral edge of the predetermined region  310 . However, the upper side of the outer peripheral edge of the region  311  may coincide with the outer peripheral edge of the predetermined region  310  before the lower side. Alternatively, the lower side of the outer peripheral edge of the region  311  may coincide with the outer peripheral edge of the predetermined region  310  before the upper side. 
     Although the second aspect of the present invention has been described by taking the third to seventh embodiments as an example, the second aspect of the present invention is not limited thereto. 
     For example, also in the second aspect, the second lamp unit  20  may have a configuration as illustrated in  FIG.  16    described above. 
     In the third to seventh embodiments, the vehicle headlight  1  including the third lamp unit  30  has been described as an example. However, the vehicle headlight  1  may not include the third lamp unit  30 . In this case, for example, the region  70  that can be irradiated with the light emitted from the second lamp unit  20  is expanded by increasing the number of the light emitting elements  23 , and the light distribution pattern of the high beam, the light distribution pattern of the low beam, and the light distribution pattern corresponding to another vehicle are formed by the light from the second lamp unit  20 . The configuration of the third lamp unit  30  is not particularly limited. The third lamp unit  30  may be, for example, a parabolic lamp. 
     In the third to seventh embodiments, the lamp units  20  and  30  each including the housings  26  and  36  have been described as an example. However, these lamp units  20  and  30  may share one housing, and members other than the housing of each of the lamp units  20  and  30  may be accommodated in the lamp chamber in one housing. 
     In the third to seventh embodiments, the predetermined region  310  not connected to the outer edge of the light distribution pattern  300  has been described as an example. However, the predetermined region  310  may be connected to the outer edge of the light distribution pattern  300 . Furthermore, the intensity of light in the predetermined region  310  may change according to, for example, a distance from the vehicle  100  to another vehicle. Furthermore, the width of the predetermined region  310  in the horizontal direction may change according to the distance from the vehicle  100  to another vehicle, for example. 
     In the third to seventh embodiments, the vehicle headlight  1  capable of switching between the first state in which the light of the high-beam light distribution pattern PH is emitted and the second state in which the light of the light distribution pattern  200  in which the light amount of the predetermined region  310  in the high-beam light distribution pattern PH is reduced is emitted has been described as an example. However, the vehicle headlight  1  only needs to be switchable between a first state in which light of a predetermined light distribution pattern is emitted and a second state in which light of a light distribution pattern in which the light amount of a predetermined region in the predetermined light distribution pattern is reduced is emitted. 
     In the third to seventh embodiments, the case where the preceding vehicle as another vehicle is detected by the detection device  110  has been described as an example. However, the third to seventh embodiments can also be applied to a case where an oncoming vehicle as another vehicle is detected by the detection device  110 . 
     In the third to seventh embodiments, the control unit CO controls the power supplied to each light emitting element  23  with reference to the table stored in the memory ME. However, the control unit CO may calculate information on the power supplied to each light emitting element  23  on the basis of the information input from the determination unit  50 , and control the power supplied to each light emitting element  23  on the basis of this information. 
     According to a first aspect of the present invention, there is provided a vehicle headlight capable of improving forward visibility of a vehicle while suppressing dazzling of an occupant of another vehicle, and according to a second aspect of the present invention, there is provided a vehicle headlight capable of suppressing a driver from feeling uncomfortable, and the vehicle headlight can be used in the field of vehicle headlights such as automobiles.