Abstract: A lighting apparatus includes a light source and a light beam separating member to separate light emitted from the light source into at least two different directions. The light beam separating member has a light incident plane on which light emitted from the light source is incident and a light output plane from which the light is output after being transmitted through the light beam separating member. In this structure, output light from the light beam separating member is clearly separated. Further, output light from the light beam separating member has characteristics that an angular width of each separated light beam is narrow.

Abstract: An information retrieving system in which information arranged by a series of more than one character is inputted and data corresponding to said input information is read out from a disk-shaped recording medium, such that every time the characters of the input information are successively inputted, a head is seeked for a direction of a recording position of the data on the disk-shaped recording medium, corresponding to the input information, and also the head is located at the recording position of the data upon completion of the entry operation of the input information.

Abstract: An optical apparatus for an optical information recording medium including a light source, two acoustooptical elements for modulating the light beam emitted from the light source and an objective lens for focusing the light beam emitted from the acoustooptical elements to the optical information recording medium, the acoustooptical elements being provided in an optical path extending from the light source to the objective lens arranged such that directions of travel of supersonic waves generated in the respective acoustooptical elements are crossed to each other.

Abstract: An optical information recording medium having a sharp front face of an optical information recording pit to thereby reduce jitter of a reproduced optical signal. The front and back end portions of a pit are made to have a sharp edge and a wider portion. In a cutting operation for an original medium used for mass production of medium, the light exposure amount to a photoresist on the original medium is controlled to increase it at the front and back edge portions of a pit.