Optical track segment intercept apparatus

Claim 2

An optical playback apparatus for reading data recorded on an optical data record (10) in a plurality of spaced-apart data track segments (35, L), including light beam forming means (12, 20, 22) for forming a light beam (18); scanning means (16, 26, 28, 30, 32, 34, 42) for scanning said light beam across said record in a scanning direction (43) from a beginning point to an end point along a scanning path (Sl-S4) to intermittently scan successive track segments (L1-L5), the beginning and end points of successive segments being different, said path having a width corresponding to the width of said track segments, said scanning means having at least one optical element (26, 34, 16) causing said light beam to move along said scanning path to modulate said light beam in accordance with the optical data on said record; and light detector means (14) for detecting said modulated light beam and producing an output signal (150) corresponding thereto, characterized by: track segment intercept means (50, 52, 60) for causing said light beam to intercept a selected one of said track segments at an intercept position to begin scanning said track segment, said intercept means including: deflection means (45, 47) between said beam forming means and said record for deflecting said light beam transversely to the scanning direction; storage means (80) for storing a discrete element of information corresponding to an amount by which said scanning light beam must be deflected transversely (Y) of said scanning path to intercept said selected track segment near the beginning point thereof, said amount including a non-integer multiple of the transverse spacing of the track segments; and adjust means (90) for producing an adjustment signal (120) corresponding to said stored information and briefly applying said signal to said deflection means to cause it to deflect said light beam transversely by said amount to said intercept position so that said light beam intercepts said selected track segment near its beginning point preparatory to the scanning of said selected segment.

Claim 3

Playback apparatus according to claim 1 wherein: the transverse orientation (Y) of said light beam with respect to said track segments (L1-L5) is a function of two independent variables, at least one of said variables defining said non-integer multiple of said spacing; said storage means (80) includes two storage portions (81, 82, 85, 86), each storage portion being adapted to storage of information relating to one of said variables; said adjust means (90) includes two adjustment portions (81, 92, 96), each adjustment portion being connected to one of said storage portions for producing an intermediate adjustment signal (120, 120a, 120b, 120c) corresponding to the information contained in said one storage portion, and summing means (65) for algebraically summing said intermediate adjustment signals together to form the adjustment signal.

Claim 4

Playback apparatus according to claim 2 wherein one of said storage portions comprises an optical alignment storage portion (82) for storing information about the optical alignment of an optical element (34, 26, 16) in said scanning means such that the adjustment portion (92) connected thereto produces an intermediate adjustment signal (120a) to compensate for any optical misalignment of said element from a reference axis, the amount of said misalignment being said non-integer multiple of said spacing and the compensating intermediate adjustment signal being proportional to said misalignment.

Claim 5

Playback apparatus according to claim 2 including: track-following means (50) for receiving said detector output signal while said record is being scanned and producing a tracking signal (110) when said scanning path is out of alignment with the center line of a track segment; and gating means (60) responsive to said detector output signal (150) for alternately gating said adjustment signal (120) and said tracking signal (110) to said deflection means (45, 47) during each scan, so that said deflection means is alternately responsive to said tracking signal to keep said light beam aligned with a track segment as it is being scanned and is selectively responsive to said adjustment signal to reposition said beam to intercept said selected track segment following an interruption of said detector output signal; one of said storage portions comprising a tracking signal storage portion for storing a sampled value (111) of said tracking signal during the scanning of each track segment so that the adjustment portion connected thereto produces an intermediate adjustment signal (120) for gating to the deflector means to shift the light beam by said non-integer multiple of track spacing following the scanning of said track segment.

Claim 6

Playback apparatus according to claim 4 wherein said storage means further includes an address storage portion (85, 86) for storing track segment-identifying information and two of said tracking signal storage portions including: a first tracking signal storage portion (81) for sampling a first said sampled value near the beginning of the scan of one track segment and for holding said first value for the duration of said scan; a second tracking signal storage portion (68) for sampling a second said sampled value and gating a signal corresponding to said value to said deflection means while said light beam is being repositioned to intercept a selected second track segment; said sampled values each being proportional to non-integer multiples of said spacing; the adjust means including an address adjustment portion (96, 97) connected to the address storage portion for producing an intermediate address adjustment signal (120b) proportional to an integer multiple of the transverse spacing of the track segments.

Claim 7

Playback apparatus according to claim 5 including: second storage means (88, 102) connected to the address adjust means for receiving and storing said intermediate address adjustment signal; second adjust means (103) connected to the second storage means for producing a compensating adjustment signal (128) in accordance with the stored intermediate address adjust signal; and second summing means (99) for algebraically summing said compensating adjust signal together with the first sampled value (120) of the tracking signal.

Claim 8

An optical playback apparatus for reading data recorded on a nonrotating optical data record (10) in a plurality of spaced apart data track segments (L1-L5), including light beam forming means (12, 20, 22) for forming a light beam (18); scanning means (16, 26, 28, 30, 32, 34, 42) for scanning said light beam across said record in a scanning direction (43) along a scanning path (S1-S4) of a width corresponding to the width of said track segment, said scanning means having at least one optical element (26, 34, 16) causing said light beam to move along said scanning path to modulate said light beam in accordance with the optical data on said record; light detector means (14) for detecting said modulated light beam and producing an output signal (150) corresponding thereto, characterized by: track segment intercept means (48, 52, 60) for causing said light beam to intercept a selected one of said track segments at an intercept position, said intercept means including: deflection means (45, 47) between said beam forming means and said record for deflecting said light beam transversely (Y) to the scanning direction (X); storage means (80) for storing information corresponding to an amount by which said scanning light beam must be deflected transversely (Y) of said scanning path to intercept said selected track segment; adjust means (90) for producing an adjustment signal (120) corresponding to said stored information and applying said signal to said deflection means to cause it to deflect said light beam so that said light beam intercepts said selected track segment preparatory to the scanning of said segment; timing means (70) for producing a timing signal; gating means (60) responsive to said timing signal for gating said adjustment signal (120) to said deflection means (45, 47) so that said deflection means is selectably responsive to said adjustment signal; said scanning means including multiple sets of optical elements (26, 34, 16) for successively scanning track segments; said storage means including means (81, 82) for storing unique information about the optical alignment of each set of optical elements, the optical alignment including an amount of misalignment which is a non-integer multiple of the spacing of said track segments; said adjust means (90, 92) employing said unique information to produce an adjustment signal (120a) to successively adjust the transverse position of said light beam as each set of optical elements begins scanning said record to compensate for said misalignment; and said timing means including means (70a) responsive to a transition of scanning from a first set of optical elements to a second set thereof for causing the storage means (80, 82) to output said unique information for said second set to the adjust means (90, 92) to cause generation of said adjustment signal before said second set begins to scan a track segment.

Claim 9

An optical playback apparatus for reading data recorded on a nonrotating optical data record (10) in a plurality of spaced apart data track segments (L1-L5), including light beam forming means (12, 20, 22) for forming a light beam (18); scanning means (16, 26, 28, 30, 32, 34, 42) for scanning said light beam across said record in a scanning direction (43) along a scanning path (S1-S4) of a width corresponding to the width of said track segment, said scanning means having at least one optical element (26, 34, 16) causing said light beam to move along said scanning path to modulate said light beam in accordance with the optical data on said record; light detector means (14) for detecting said modulated light beam and producing an output signal (150) corresponding thereto, characterized by: track segment intercept means (48, 52, 60) for causing said light beam to intercept a selected one of said track segments at an intercept position, said intercept means including: deflection means (45, 47) between said beam forming means and said record for deflecting said light beam transversely (Y) to the scanning direction (X); storage means (80) for storing information corresponding to an amount by which said scanning light beam must be deflected transversely (Y) of said scanning path to intercept said selected track segment; adjust means (90) for producing an adjustment signal (120) corresponding to said stored information and applying said signal to said deflection means to cause it to deflect said light beam so that said light beam intercepts said selected track segment preparatory to the scanning of said segment; timing means (70) for producing a timing signal; gating means (60) responsive to said timing signal for gating said adjustment signal (120) to said deflection means (45, 47) so that said deflection means is selectably responsive to said adjustment signal; said scanning means including multiple sets of optical elements (26, 34, 16) for successively scanning track segments; said storage means including means (81, 82) for storing unique information about the optical alignment of each set of optical elements, the optical alignment including an amount of misalignment which is a non-integer multiple of the spacing of said track segments; said adjust means (90, 92) employing said unique information to produce an adjustment signal (120a) to successively adjust the transverse position of said light beam as each set of optical elements begins scanning said record to compensate for said misalignment; and said timing means including means (70a) responsive to a transition of scanning from a first set of optical elements to a second set thereof for causing the storage means (80, 82) to output said unique information for said second set to the adjust means (90, 92) to cause generation of said adjustment signal before said second set begins to scan a track segment.

Claim 10

Playback apparatus according to claim 7, wherein said scanning means includes mark means (38) for uniquely identifying one of said sets of optical elements and second detector means (40) for detecting said mark means and producing an output signal (170) corresponding thereto.

Claim 11

Playback apparatus according to claim 8, wherein said second detector means output signal (170) is input to one of said storage and adjust means (80, 82, 83, 90, 92) and causes said storage and adjust means to produce a selected adjustment signal (120a) for positioning said light beam on a track segment preparatory to said identified set of optical elements scanning said light beam across said record.

Claim 12

Intercept control apparatus according to claim 7 wherein said stored information includes a digital signal having an equivalent analog value which is proportional to the amount of transverse misalignment of the scanning light beam relative to a reference position.

Claim 13

In an optical playback apparatus for reading data recorded on a non-rotating optical data record (10) in a plurality of spaced-apart data track segments (L1-L5) each extending from side to side across the record from a beginning point to an ending point at opposite sides of the record; the playback apparatus including scanning means (16, 26, 28, 30, 32, 34, 42) for scanning a light beam (18) across the record along said track segments (Ll-L5) to modulate the light beam in accordance with the data recorded thereon, light detector means (14) for detecting the modulated light beam (46) and producing an output signal (150) corresponding thereto, the scanning means including an optical element (26, 34, 16) for transmitting said beam to the record, the playback apparatus being subject to errors in the transverse alignment of the beam with the track segments when the beam is shifted from the end point of one track segment following scanning thereof to the beginning point of the next successive track segment to commence scanning said next segment, said errors including a non-integer-multiple of the center-to-center transverse spacing of the track segments, characterized by: track intercept means (48, 52, 60) for positioning the light beam transversely of the track segments to intercept each successive track segment at substantially the beginning point thereof, said track intercept means comprising: deflection means (48) in the path of said light beam for deflecting the light beam transversely of said track segments; adjust means (90) for producing an adjustment signal for controlling the deflection means to transversely (Y) reposition the light beam a distance from its position at the end point of a first track segment at one side of the record (10) so as to intercept a second track segment at substantially the beginning point thereof on the opposite side of the record and thereby compensate for said alignment errors, said distance including a non-integer multiple of said track spacing; timing means (70) responsive to a transition from scanning said first segment to the scanning of said second segment for producing a timing signal; and gating means (60) responsive to the timing signal to briefly apply the adjustment signal (120) to the deflection means (47, 45) in time to reposition the beam for scanning a beginning portion of said second track segment.

Claim 14

In an optical playback apparatus for reading data recorded on a non-rotating optical data record (10) in a plurality of spaced-apart data track segments (L1-L5) each extending from side to side across the record from a beginning point to an ending point at opposite sides of the record; the playback apparatus including scanning means (16, 26, 28, 30, 32, 34, 42) for scanning a light beam (18) across the record along said track segments (Ll-L5) to modulate the light beam in accordance with the data recorded thereon, light detector means (14) for detecting the modulated light beam (46) and producing an output signal (150) corresponding thereto, the scanning means including an optical element (26, 34, 16) for transmitting said beam to the record, the playback apparatus being subject to errors in the transverse alignment of the beam with the track segments when the beam is shifted from the end point of one track segment following scanning thereof to the beginning point of the next successive track segment to commence scanning said next segment, said errors including a non-integer-multiple of the center-to-center transverse spacing of the track segments, characterized by: track intercept means (48, 52, 60) for positioning the light beam transversely of the track segments to intercept each successive track segment at substantially the beginning point thereof, said track intercept means comprising: deflection means (48) in the path of said light beam for deflecting the light beam transversely of said track segments; adjust means (90) for producing an adjustment signal for controlling the deflection means to transversely (Y) reposition the light beam a distance from its position at the end point of a first track segment at one side of the record (10) so as to intercept a second track segment at substantially the beginning point thereof on the opposite side of the record and thereby compensate for said alignment errors, said distance including a non-integer multiple of said track spacing; timing means (70) responsive to a transition from scanning said first segment to the scanning of said second segment for producing a timing signal; and gating means (60) responsive to the timing signal to briefly apply the adjustment signal (120) to the deflection means (47, 45) in time to reposition the beam for scanning a beginning portion of said second track segment.

Claim 15

Optical playback apparatus according to claim 11 including at least two of said optical elements (16, 16'), the second element (16') being positioned to scan the light beam along the second track segment following scanning of the light beam along the first track segment by the first element (16), in which: the track intercept means includes optical alignment storage means (80, 82) for storing an optical alignment signal corresponding to each of said optical elements and for outputting said alignment signal in response to the timing signal; the adjust means (90, 92) being connected to the storage means for producing said adjustment signal in accordance with said stored alignment signal upon occurrence of said timing signal.

Claim 16

Optical playback apparatus according to claim 11 including a track-following means (50) for providing a tracking signal (110) to the deflection means during the scanning of each of said tracking segments, in which: the track intercept means includes a tracking signal storage means (80, 81) for sampling and storing a sampled value of the tracking signal during the scanning of each track segment; the timing means (70) including first timing means (72, 73) for controlling the tracking signal storage portion to sample and store said sampled value during the scanning of a beginning portion of the first track segment and second timing means (71) for controlling the gating means (60) to apply the adjustment signal (120) including said sampled value to the deflection means (48) following completion of scanning of the first track segment.

Claim 17

Optical playback apparatus according to claim 13 wherein the timing means (70) includes means (51) responsive to a temporary interruption of the light detector means output signal upon completion of scanning of said first-scanned track segment to cause said deflection means (48) to reposition said light beam according to said adjustment signal prior to sampling a second value of said tracking signal for a second track segment.