Illumination device and projector

An illumination device comprising:

• a light emitting element configured to emit first light in a first wavelength band;
• a wavelength conversion element configured to convert the first light into second light in a second wavelength band different from the first wavelength band;
• a first optical element configured to reflect one of the first light and the second light, transmit another of the first light and the second light, and make the first light enter the wavelength conversion element;
• a second optical element having a first area configured to transmit the second light, and a second area configured to transmit a part of the first light and reflect another part of the first light;
• and
• a third optical element having a third area configured to transmit the second light, and a fourth area configured to transmit a part of the first light and reflect another part of the first light, wherein
• in the second optical element, a transmittance of the first light in the first area is higher than a transmittance of the first light in the second area,
• a position of the second optical element is made switchable between a first position where the second light which is transmitted or reflected by the first optical element enters the first area, and the first light emitted from the wavelength conversion element enters the second area, and a second position where the second light which is transmitted or reflected by the first optical element fails to enter the first area, and the first light emitted from the wavelength conversion element fails to enter the second area,
• in the third optical element, a transmittance of the first light in the third area is higher than a transmittance of the first light in the fourth area,
• a position of the third optical element is made switchable between a third position where the second light which is transmitted or reflected by the first optical element enters the third area, and the first light emitted from the wavelength conversion element enters the fourth area, and a fourth position where the second light which is transmitted or reflected by the first optical element fails to enter the third area, and the first light emitted from the wavelength conversion element fails to enter the fourth area, and
• the transmittance of the first light in the fourth area of the third optical element is different from the transmittance of the first light in the second area of the second optical element.