Abstract: A light guiding apparatus comprising: a light guiding substrate; a light receiving unit including first and second units provided on a surface of the substrate, the first and second units transmitting received rays along first and second paths in the substrate as first and second light beams, respectively; a first direction changing unit for the first light beam; a second direction changing unit for the second light beam; and a light emitting unit receiving the first and the second light beams, combining the beams for emission and provided on the surface, wherein on the surface the center of the minimum circle encompassing the first unit is located farther away from the light emitting unit than the center of the minimum circle encompassing the second unit and the first path runs through the portion of the substrate on which the second unit is provided.

Abstract: Provided is a wide angle optical imaging system composed of four lenses, the wide angle optical imaging system allowing various types of aberrations including chromatic aberration of magnification to be sufficiently reduced. The wide angle optical imaging system includes the following arranged from the object side to the image plane side: a first lens that is a negative meniscus lens having a convex surface on the object side; a second lens that is negative; a third lens that is positive; an aperture stop; and a fourth lens that is positive, wherein the following expressions are satisfied, where v2, v3, and v4 represent Abbe numbers of materials that form the second to fourth lenses with respect to a d-line, respectively, f2 and f3 represent focal distances of the second and third lenses, respectively, and f represents a focal distance of the whole optical system: v2>35 (1) v3<45 (2) v4>35 (3) v2?v3?10 (4) v4?v3?10 (5) ?2.3?f2/f??1.5 (6) 3.0?f3/f?4.

Abstract: An illuminating device includes a light source and a light receiving surface, first and second light exit surfaces. When a point at the edge of the light emitting surface is P2 and an axis which passes through a center P1 of a light emitting surface and is perpendicular to the light emitting surface is an optical axis, the optical element has a hollow around the optical axis. The first light exit surface is such that x coordinate of a point most distant from the optical axis on the first light exit surface is at least 1.5 times x coordinate of P2, that in 80% or more of an area in which x coordinate of a point is at least the x coordinate of another point P3, an angle of incidence of light emitted at P1 is at least the critical angle and that in 80% or more of an area in which x coordinate of a point is equal to or smaller than x coordinate of another point P4, an angle of incidence of light emitted at P2 is smaller than the critical angle.

Abstract: A vehicular lamp includes a light source, a reflector, a shade, and the projector lens. Light emitted from the light source is reflected by the reflector, and the light is partially blocked by the shade. Light which is not blocked is transmitted through the projector lens, and an object ahead of a vehicle is irradiated with the light. A diffraction grating is provided in a region including an end portion of a light passing region of at least one surface in the projector lens in order to reduce color separation.

Abstract: An illuminating device includes a light source (101) and an optical element including a light receiving surface (203), first and second light exit surfaces (205, 207). When the center of a light emitting surface (201) is designated as P1, a point at the edge of the light emitting surface is designated as P2 and an axis which passes through P1 and is perpendicular to the light emitting surface is designated as an optical axis, the optical element has a hollow around the optical axis with respect to the edge.

Abstract: A vehicular lamp includes a light source, a reflector, a shade, and the projector lens. Light emitted from the light source is reflected by the reflector, and the light is partially blocked by the shade. Light which is not blocked is transmitted through the projector lens, and an object ahead of a vehicle is irradiated with the light. A diffraction grating is provided in a region including an end portion of a light passing region of at least one surface in the projector lens in order to reduce color separation. Magnitude of fD/f/Abbe and a position of the shade on an optical axis are determined according to a correlated color temperature of the light source so as to reduce the color separation caused by a characteristic of the light source. f is a focal distance of the projector lens, with the focal distance of the projector lens being determined by a marginal ray passing through the end portion.