Projection optical system and image projector

An image projector for projecting an image ray bundle onto a projection surface,

• the image projector comprising:
• an image display element that forms the image ray bundle;
• and
• a projection optical system that includes
• a transmissive optical system positioned on a side of an emission surface of the image display element, the transmissive optical system having positive power, and
• a reflective optical system including at least one mirror for reflecting, toward the projection surface, light rays emitted from the transmissive optical system,
• wherein
• the transmissive optical system includes:
• an aperture stop;
• at least one positive lens disposed closer to the image display element than the aperture stop is;
• a first positive lens having a meniscus shape, the first positive lens being disposed closer to the projection surface than the aperture stop is;
• a negative lens disposed closer to the projection surface than the aperture stop is;
• and
• a second positive lens having a meniscus shape, the second positive lens being disposed closer to the projection surface than the aperture stop is,
• the first positive lens and the second positive lens are disposed so that a concave surface of the first positive lens and a concave surface of the second positive lens face each other,
• the negative lens is disposed between the first positive lens and the second positive lens, and
• during focusing, a spacing between the first positive lens and the negative lens and a spacing between the second positive lens and the negative lens remain unchanged.