Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
226 words
An optical information recording and reproducing apparatus, in which a disc-like information carrier (5) having an information recording and storing surface (R) provided previously with guide tracks (8, 30) in a concentric or spiral pattern is driven to be rotated, said information recording and storing surface (R) being irradiated with a light beam (2) under the guidance of said guide tracks (8, 30) for recording or reproducing information, while said light beam (2) is caused to be moved in a predetermined radial direction over said information recording and storing surface (R) for searching a location (57) to be irradiated with said light beam, whereby output signals (34a, 34b) produced from photoelectric detector means (19a, 19b) upon every traversal of said guide tracks (8, 30) by said light beam (2) are sequentially counted, to thereby determine said location (57) in accordance with the counted value; comprising the improvement in which, for sealing the location (57) on said information carrier to be irradiated with said light beam (2), the traversal direction in which said light beam (2) traverses said guide track (8, 30) is detected, and the signals produced upon every traversal of said track (8, 30) by said light beam (2) are sequentially counted up or down (by 49) in dependence on said traversal direction, whereby said location is determined in accordance with the resultant count value.
Claim 2
Dependent Claim
226 words
An optical information recording and reproducing apparatus, in which a disc-like information carrier (5) having an information recording and storing surface (R) provided previously with guide tracks (8, 30) in a concentric or spiral pattern is driven to be rotated, said information recording and storing surface (R) being irradiated with a light beam (2) under the guidance of said guide tracks (8, 30) for recording or reproducing information, while said light beam (2) is caused to be moved in a predetermined radial direction over said information recording and storing surface (R) for searching a location (57) to be irradiated with said light beam, whereby output signals (34a, 34b) produced from photoelectric detector means (19a, 19b) upon every traversal of said guide tracks (8, 30) by said light beam (2) are sequentially counted, to thereby determine said location (57) in accordance with the counted value; comprising the improvement in which, for sealing the location (57) on said information carrier to be irradiated with said light beam (2), the traversal direction in which said light beam (2) traverses said guide track (8, 30) is detected, and the signals produced upon every traversal of said track (8, 30) by said light beam (2) are sequentially counted up or down (by 49) in dependence on said traversal direction, whereby said location is determined in accordance with the resultant count value.
Claim 3
Dependent Claim
117 words
An optical information recording and reproducing apparatus according to claim 1, wherein detection of the direction in which said light beam (2) traverses said guide track (8, 30) is effected by introducing simultaneously light rays (17b) of said light beam (2) transmitted through or reflected from said information carrier to a photoelectric detector (19) divided into halves (19a, 19b) along the longitudinal direction of said guide track (8, 30), and a difference signal (23) and a sum signal (28) are derived from the output signals (34a, 34b) from said photoelectric detector halves (19a, 19b), whereby said traversal direction is determined on the basis of difference in phase between said difference signal (23) and said sum signal (28).
Claim 4
Dependent Claim
118 words
An optical information recording and reproducing apparatus according to claim 1, said information carrier (5) having information recorded, wherein detection of the direction in which said light beam (27) traverses said guide track (8, 30) is effected by introducing simultaneously light rays (17b) of said light beam transmitted through or reflected from said information carrier (5) to a photoelectric detector (19) divided into halves (19a, 19b) along the longitudinal direction of said guide track, and a difference signal (a) is derived from the output signals from said photoelectric detector halves (19a, 19b), whereby said traversal direction is determined on the basis of difference in phase between said difference signal (a) and a reproduced signal (c) of said information.