Projection optical system, image projection apparatus, and image projection system

An image projection apparatus comprising:

• a light source;
• and
• a projection optical system that projects an image on a basis of light from the light source,
• the projection optical system including, in order from a side on which the light source is located to a projection side along an optical axis:
• a first lens group that includes one or more lenses, has a positive focal length, and condenses light from the light source on a primary image-forming point that is an image of the light source,
• a deflector that scans light from the first lens group, and
• a second lens group that includes one or more lenses, has a positive focal length, and forms an image of light from the deflector at a position of a secondary image-forming point that is an image of the primary image-forming point, and
• the first lens group forming the primary image-forming point between the first lens group and the second lens group along the optical axis.

An image projection system comprising:

• a light source;
• a projection optical system that projects an image on a basis of light from the light source;
• and
• an eyepiece optical system for viewing of a projected image by the projection optical system,
• the projection optical system including, in order from a side on which the light source is located to a projection side along an optical axis:
• a first lens group that includes one or more lenses, has a positive focal length, and condenses light from the light source on a primary image-forming point that is an image of the light source,
• a deflector that scans light from the first lens group, and
• a second lens group that includes one or more lenses, has a positive focal length, and forms an image of light from the deflector at a position of a secondary image-forming point that is an image of the primary image-forming point, and
• the first lens group forming the primary image-forming point between the first lens group and the second lens group along the optical axis.