Imaging optical system, projection display device, and imaging apparatus

An imaging optical system consisting of, in order from a magnification side to a reduction side:

• a first optical system that has at least one lens and forms an intermediate image at a position conjugate to a magnification side imaging surface;
• and
• a second optical system that has at least one lens and re-forms the intermediate image on a reduction side imaging surface,
• wherein the imaging optical system is configured to be telecentric on the reduction side, and
• wherein assuming that
• a height of a principal ray with a maximum angle of view on a lens surface closest to the magnification side in the second optical system is hkc2,
• a height of the principal ray with the maximum angle of view on a lens surface closest to the reduction side in the first optical system is hrc1,
• a height of an on-axis marginal ray of the lens surface closest to the magnification side in the second optical system is hkm2, and
• a height of the on-axis marginal ray at a position where the principal ray with the maximum angle of view intersects with an optical axis in the second optical system is hs,
• Conditional Expressions (1-1) and (2) are satisfied,
• 1.9≤hkc2/hrc1<2.5 (1-1)
• hkm2/hs<0.8 (2).