DIFFRACTION OPTICAL ELEMENT, OPTICAL SYSTEM WITH THE SAME, IMAGE CAPTURING DEVICE, AND LENS DEVICE

Japanese Patent JP2018004914

A

PROBLEM TO BE SOLVED: To provide a diffraction optical element capable of reducing flare while maintaining optical performance.SOLUTION: A diffraction optical element 10 comprises a substrate 1, a first diffraction grating 4, and a second diffraction grating 5. A refractive index of the first diffraction grating 4 for the d-ray is greater than that of the second diffraction grating 5 for the d-ray. A refractive index Nof the substrate 1 for the d-ray and the refractive index Nof the first diffraction grating 4 for the d-ray satisfy conditions expressed as: 1.45