Patent ID: 8072847

Claim:
An optical device, comprising: an optical element having a core; the core including: a side surface defining a substantially parabolic outline of the core; and an apex portion having a light emitting surface which is defined by two opening ends and through which light is to be emitted, wherein light having been introduced into the core and having reached the side surface is reflected by the side surface and converged at a focal point of the parabola before being emitted through the light emitting surface, a light guiding unit which is adapted to irradiate the core with light from a light source to make a light spot thereon; and a light introducing portion which is provided at a position on the core at which the light spot is to be formed by the light guiding unit, and is adapted to introduce into the core the light forming the light spot, wherein the light introduced into the core by the light introducing portion travels substantially parallel to an axis of the parabola which passes through the focal point of the parabola and is perpendicular to a directrix of the parabola, wherein a maximum intensity point at which light intensity is maximum within the light spot formed by the light guiding unit on the core is deviated from the axis of the parabola.