Illumination device having wedge prisms and driving portion with multiple gears

An illumination device comprising:

• a light source to emit light;
• a pair of wedge prisms to receive the light and deflect the received light;
• and
• a driving portion including a first gear and a second gear, the driving portion causing the pair of wedge prisms to rotate about a first rotation axis of the pair of wedge prisms by using the first gear and the second gear,
• wherein the pair of wedge prisms include a first wedge prism held by a first barrel and a second wedge prism held by a second barrel;
• wherein the first barrel is disposed inside the second barrel;
• wherein a third gear whose center axis is the first rotation axis is provided on an outer periphery of the first barrel;
• wherein a fourth gear whose center axis is the first rotation axis is provided on an inner periphery of the second barrel;
• wherein the first gear is disposed on an outer peripheral side of the third gear and meshes with the third gear;
• and
• wherein the second gear is disposed on an inner peripheral side of the fourth gear and meshes with the fourth gear.