| 摘要 |
A diffractive optical element disclosed in the present application includes: a base which is made of a first optical material containing a first resin and which has a diffraction grating in its surface; and an optical adjustment layer which is made of a second optical material containing a second resin and inorganic particles and which is provided on the base so as to cover the diffraction grating, whereinΔSP which is defined by a formula shown below is not less than−0.7 and not more than +0.7 [cal/cm3]1/2:ΔSP=[a solubility parameter of the second resin]−[a solubility parameter of the first resin], and a design order of diffraction caused by the diffraction grating is nth order, and unwanted order diffracted light of n+1th order in a wavelength range of not less than 400 nm and not more than 700 nm is not more than 7%. |
