In order to achieve the athermalization of conformal optical systms

an infrared imaging system was presented by using the hybrid refractive/diffractive elements made of Si

Ge

and ZnSe and a diffraction surface mounted on the dome’s inner surface. The aberration characteristics of conformal optics and the aberration

thermal and dispersion characteristics of diffractive elements were introduced

then an athermal method by using the thermal compensation characteristics of the diffractive surface on the dome’s inner surface was given.A gimbaled conformal optical system used in mid-IR wavelength was designed. After analyzing the design

it is shown that the conformal optical system makes full use of the charateristics of diffraction elements in good phase compensation

small heat expansion coefficients and big dispersion factors and can work well at -40～70 ℃ while its average MTF value is higher than 0.43 in each Field of Regard (FOR).