An optical device includes a reflector-section that includes a light-ingress surface for receiving light from a light source, a reflector surface for reflecting the light based on total internal reflection, and a light-egress surface through which the reflected light exits the optical device. When the light source is at a predetermined position with respect to the optical device, an angle of incidence (θi) of the light at the light-egress surface is a polarization angle at which a p-polarized component of the light is transmitted through the light-egress surface without being reflected by the light-egress surface. Thus, unwanted reflections at the light-egress surface can be reduced and thereby unwanted scattering of light is reduced while having good transmitting efficacy.