Patent ID: 8493644

Claim:
An optical writing device which outputs image light to be recorded to a display recording medium, comprising a spatial light modulating element in which a plurality of pixels that spatially modulate image forming light emitted from a surface-type light source section into the image light are arranged in matrix within a plane, and an optical element which allows the image light to make incident on the display recording medium by restricting an emission angle range of the image light emitted from the spatial light modulating element, wherein: the optical element includes a two-dimensional periodic structural body in which transparent layers that transmit the image light and light absorption layers that restrict a range of emitted directions of the image light that transmits through the transparent layer are alternately arranged within the plane in a repeated manner; the two-dimensional periodic structural body includes a plurality of periodic structure sections along a direction that is orthogonal to the direction along which the transparent layers and the light absorption layers are arranged alternately in a repeated manner; at least a part of the plurality of periodic structure sections is in a periodic structure in which the transparent layers and the light absorption layers are arranged alternately in a repeated manner by varying phases of spatial frequencies of the transparent layers that are neighboring to each other in the orthogonal direction; and repeated period pitches of the transparent layers and the light absorption layers in the two orthogonal directions of the two-dimensional periodic structural body are set to match with each other, and the repeated period pitches are set to be narrower than a layout pitch of the pixels of the spatial light modulating element.