Abstract: An optical unit includes a light source configured to irradiate an object with light, a first polarizing element configured to convert emitted light emitted from the light source to linearly polarized light, a second polarizing element configured to cause reflection light from the object to transmit through the second polarizing element, a polarization axis of the second polarizing element being 90° orthogonal to a polarization axis of the first polarizing element, a first wavelength plate disposed to overlap with the first polarizing element and configured to convert the emitted light from the light source to circularly polarized light or elliptically polarized light, and a second wavelength plate disposed to overlap with the second polarizing element, a phase difference of the second wavelength plate being equal to a phase difference of the first wavelength plate. The first wavelength plate is revolvable and/or the second polarizing element is revolvable.

Abstract: Provided is a lighting device including: a support portion disposed in front of a forehead of a head of a wearer; a light source unit provided to the support portion, the light source unit including a light source which irradiates an object with light, and a condensing lens which condenses the light emitted from the light source; and a transmission member configured to transmit reflected light from the object so as to allow the wearer to visually recognize the reflected light, the transmission member being provided to the support portion and disposed in front of an eye of the wearer, wherein the light source unit includes a first polarizing element which converts emitted light emitted from the light source to linearly polarized light, and the transmission member includes a second polarizing element which is disposed 90° orthogonal to a polarization axis of the first polarizing element.

Abstract: By providing a surface light source that planarly emits first illuminating light FL in the blue wavelength region of 400 to 500 nm and second illuminating light SL in the red wavelength region of 600 to 660 nm, and by emitting illuminating light in these specific wavelength region, it makes it possible to visually identify the position of veins easily.