Abstract: In a midst of switching light distribution patterns from a first light distribution pattern to a second light distribution pattern, in the event that a situation is detected in which the first light distribution pattern needs to be switched to a third light distribution pattern which differs from the second light distribution pattern, and in switching from the second light distribution pattern to the third light distribution pattern, in the event that in a plurality of partial areas which make up the third light distribution pattern, there exist a plurality of switching partial areas where an upward trend in illuminance changes to a downward trend, a control unit of a vehicle lamp system controls the drive of semiconductor light emitting devices which illuminate the plurality of switching partial areas so that the switching to the third light distribution pattern can be executed within a predetermined length of time.

Abstract: In a midst of switching light distribution patterns from a first light distribution pattern to a second light distribution pattern, in the event that a situation is detected in which the first light distribution pattern needs to be switched to a third light distribution pattern which differs from the second light distribution pattern, and in switching from the second light distribution pattern to the third light distribution pattern, in the event that in a plurality of partial areas which make up the third light distribution pattern, there exist a plurality of switching partial areas where an upward trend in illuminance changes to a downward trend, a control unit of a vehicle lamp system controls the drive of semiconductor light emitting devices which illuminate the plurality of switching partial areas so that the switching to the third light distribution pattern can be executed within a predetermined length of time.