according to the present disclosure , a first optical system includes a first light source and emits a first illumination light . a second optical system includes a second light source and emits a second illumination light . a controller controls turning - on / off of the first light source and the second light source . the first optical system and the second optical system are configured such that a first illumination standard is satisfied by the first illumination light and the second illumination light . the first optical system is configured such that a second illumination standard is satisfied by the first illumination light . the controller allows the turning - on of the first light source when the turning - on of the second light source is disabled , and prohibits the turning - on of the second light source when the turning - on of the first light source is disabled .