Light irradiating device and sensor

A light irradiating device comprising:

• a light source;
• and
• a liquid crystal hologram element,
• wherein light that originates from the light source and is incident on the liquid crystal hologram element is diffracted by the liquid crystal hologram element in a plurality of different directions as the light passes therethrough,
• the liquid crystal hologram element includes a liquid crystal hologram layer,
• the liquid crystal hologram layer is a layer that consists of a computer generated hologram and is formed of a composition including a liquid crystal compound,
• the liquid crystal hologram layer includes a plurality of regions in which directions of optical axes derived from the liquid crystal compound are different from each other,
• the computer generated hologram is formed by two-dimensionally arranging the plurality of regions so that a dot pattern is projected to an object to be detected, and
• the light irradiating device further comprises a polarization switching element provided between the light source and the liquid crystal hologram element, wherein the light from the light source is polarized and the polarization switching element switches a polarization state of the light emitted from the light source.