Imaging device, and diffraction grating lens for use in the device

An imaging device having a single lens, the device comprising:

• a diffraction grating lens as the single lens;
• an angle-of-view restriction member for defining a viewing angle of the diffraction grating lens;
• and
• an imaging element for receiving light transmitted through the diffraction grating lens, wherein,
• the diffraction grating lens includes
• a lens substrate having a first face and a second face, at least one of the two faces having an aspheric shape, and the lens substrate having a positive power, and
• a diffraction grating formed on one of the two faces of the lens substrate;
• and
• [
• eq
• .
• ⁢
• 15
• ]
• 0.21
• ⁢
• ⁢
• m
• 2
• ⁢
• ⁢
• v
• d
• ⁢
• λ
• ⁢
• f
• h
• max
• <
• Λ
• min
• <
• 0.30
• ⁢
• ⁢
• m
• 2
• ⁢
• v
• d
• ⁢
• λ
• ⁢
• f
• h
• max
• (
• 1
• )
• is satisfied, where:
• is a minimum zonal pitch;
• m is an order of diffraction;
• vd is an Abbe number of the lens substrate material with respect to the d-line;
• λ is a wavelength;
• f is an effective focal length;
• and hmax is an effective radius of the face on which the diffraction grating is formed.