Patent ID: 7168826

Claim:
A light guiding apparatus which guides emitted light emitted from a light source, comprising: a first transparent member which is solid; a second transparent member which is solid and is moved relatively to the first transparent member to take a contact position where the second transparent member is in contact with the first transparent member or a separate position where the second transparent member is separated from the first transparent member; and a transparent member holding portion which moves the second transparent member relatively to the first transparent member, and holds the second transparent member in one of the contact or separate position, wherein the first transparent member is provided with a light entry surface into which the emitted light enters, a first side surface in which light guidance is performed to the emitted light entering the light entry surface by way of complete reflection by an inner surface thereof when the second transparent member is in the separate position, and in which the emitted light is transmitted into the second transparent member when the second transparent member is in contact, and a first light emitting end surface which emits the emitted light which is guided, and wherein the second transparent member is provided with a second side surface which faces the first side surface so that the second side surface can contact the first side surface, and a third side surface in which, when the second side surface and the first side surface are in contact with each other, light guidance toward at least the first light emitting end surface is performed to the emitted light which is entering the second side surface by way of complete reflection by an inner surface thereof.