JP2007004851A - Optical recording medium, reproducing method of optical recording medium and reproducing apparatus of optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium wherein two tracks can be simultaneously and consecutively reproduced without jumping tracks in a reproducing apparatus having one main beam, to provide a reproducing method of the optical recording medium and to provide the reproducing apparatus. <P>SOLUTION: The optical recording medium is constituted so that a land track and first and second groove tracks adjacent to the land track are irradiated with the main beam, reflected light from the optical recording medium is detected by a photodetector having a plurality of detection regions and arithmetic operation of output signals of the detection regions is performed to reproduce information recorded in the groove tracks, wherein the first and the second groove tracks have a double spiral structure in which independent spirals are formed, therefore the land track can be followed by the main beam without jumping tracks for every one rotation of the optical recording medium, so that information recorded in the first and the second groove tracks can be simultaneously and consecutively reproduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical recording medium, an optical recording medium reproducing method, and an optical recording medium reproducing apparatus, and more particularly to an optical recording medium, an optical recording medium reproducing method, and an optical recording medium reproducing apparatus that increase the data transfer rate. It is.

One of the development issues of optical recording media is to increase the data transfer rate. In order to increase the data transfer rate, in CD, DVD, etc., the recording / reproducing linear velocity is several times the standard velocity or more. However, the spindle motor that rotates the optical recording medium has a limit on the rotation speed, and if a spindle motor that can rotate at high speed is adopted, the motor becomes large, making it difficult to reduce the size of the apparatus and increasing costs. To face.
Also, since the substrate of the optical recording medium is required to have mechanical characteristics that can withstand high-speed rotation, a manufacturing technique with higher accuracy than before is required for manufacturing the substrate, and as a result, the manufacturing cost of the recording medium also increases. There is a problem.
Another method for improving the transfer rate is a multi-beam method in which a plurality of reading light beams are conventionally used. However, in this method, since the number of optical elements increases, adjustment between the optical elements becomes complicated. Further, since signal processing circuits are required for the number of light beams, signal processing becomes complicated. That is, this method also has problems such as an increase in the cost of the reproducing apparatus and difficulty in downsizing the apparatus.
As a conventional technique, Patent Document 1 discloses that a recording medium is formed with a pit row including a plurality of pits that can be simultaneously scanned by one light beam, and these pits are arranged based on information. Thus, an optical recording medium and a reproducing apparatus that can improve data reading accuracy even when minute information pits exceeding the diffraction limit of light are formed are disclosed. The pit arrangement is specified from the sum signal obtained by adding the signals output in each detection area, and the remaining 2 from the sum output in the two detection areas having a diagonal position relative to each other. This is based on a difference signal obtained by subtracting the sums output from two detection areas.
In Patent Document 2, when three tracks Tr1, Tr2, and Tr3 are accessed simultaneously, Tr2 is used as a redundant track, and a redundant bit is recorded in Tr2, so that a reproduction signal is either Tr1 or Tr3. A recording / reproducing method capable of separately reproducing a recording domain from a recording medium on which information is recorded at a track pitch such that a plurality of tracks are accessed simultaneously is disclosed. .
In Patent Document 3, a multi-beam head having a larger number of beams than that of the copy source head is used, and the head is controlled to jump a predetermined track according to the format of the disk to be copied. In addition to the conventional speed-up means, a technique that enables double-speed high-speed dubbing by copying in parallel is disclosed.
JP 2004-227627 A JP 10-79170 A JP-A-7-272274

The prior arts disclosed in Patent Documents 1 and 2 are all related to high recording density, and there is an advantage that the transfer rate can be improved by increasing the recording density. This is a technique for realizing high-density recording by combining two marks on a track and its adjacent tracks or a set of three marks on three adjacent tracks. Accordingly, information cannot be reproduced accurately unless two or three marks are recorded at the correct positions. However, in a CLV recording method with a constant linear velocity such as CD and DVD, it is difficult to record with the mark positions accurately aligned in the radial direction. For example, in CD-R, DVD-R, etc., when new information is added after information already recorded, a certain degree of overlap is allowed at the joint. In other words, it is difficult to perfectly match the joints. Furthermore, it is difficult to align the mark positions between adjacent tracks with an inexpensive recording / reproducing apparatus, and a high-precision control mechanism is required to achieve this, resulting in an increase in cost.
In addition, since a recording medium on which information is recorded with a plurality of pits aligned in the radial direction as a set is a special recording method, an optical recording medium recorded by this method cannot be reproduced by an existing recording / reproducing apparatus. A compatibility defect occurs.
The prior art disclosed in Patent Document 3 is a track jump method in a multi-beam recording / reproducing apparatus, and cannot be applied to a one-beam recording / reproducing apparatus. When multi-beams are employed in the recording apparatus, the number of light sources, optical systems, and detection systems is required as many as the number of beams, and the assembly and adjustment thereof are complicated, leading to a problem of increasing costs.
In view of the above problems, the present invention provides an optical recording medium, an optical recording medium playback method, and a playback apparatus that can simultaneously play back two tracks without jumping a track in a playback apparatus having one main beam. For the purpose.

In order to solve this problem, the present invention provides a land track of an optical recording medium and a first and a second groove track adjacent to the land track by a main beam emitted through an objective lens. And detecting the amount of light reflected from the optical recording medium by a detector having a detection area divided into at least two in the track direction, and the sum of output signals from the detection areas is RF, and the detection areas When the difference between the output signals from PP is PP, the constant is C, the information recorded on the first groove track is RF1, and the information recorded on the second groove track is RF2, the RF1 is RF1 = RF + C. • Recorded on the first and second groove tracks by calculating by PP and calculating RF2 by RF2 = RF−C · PP. In the optical recording medium to read information are, the first and second groove tracks, characterized in that it is a double spiral structure formed as an independent spiral track.
The optical recording medium of the present invention irradiates the main beam to the land track and the first and second groove tracks adjacent thereto, and detects the reflected light from the optical recording medium by a photodetector having a plurality of detection regions. An optical recording medium that reproduces information recorded on each groove track by calculating the output signal of each detection area, and the first and second groove tracks are formed by independent spirals. Due to the double spiral structure, the main beam can follow the land track without causing a track jump every rotation of the optical recording medium, so that information recorded on the first and second groove tracks can be reproduced simultaneously. can do.

According to a second aspect of the present invention, either one of the first and second groove tracks is recorded by meandering in a radial direction corresponding to address information, and the address information is recorded in the adjacent first and second groove tracks. It is shared by a groove track.
The address information is shared by the first and second groove tracks, and the first groove track is recorded by wobbling the groove in the radial direction according to the address information, and the second groove is a straight groove.
According to a third aspect of the present invention, the main beam emitted through the objective lens is irradiated so as to include the land track of the optical recording medium and the first and second groove tracks adjacent to the land track. Is detected by a detector having a detection area divided into at least two in the track direction, the sum of the output signals from each detection area is RF, the difference between the output signals from each detection area is PP, and the constant is C, assuming that the information recorded on the first groove track is RF1, and the information recorded on the second groove track is RF2, the RF1 is calculated by RF1 = RF + C · PP, and the RF2 is RF2 = Reproduction method of optical recording medium for detecting information recorded on first and second groove tracks by calculation using RF-C · PP The first and second groove tracks of the optical recording medium have a double spiral structure formed as a spiral track if they are independent, and address information is recorded as wobbles on the first groove track. A first sub-beam is applied to the first groove track, and the reflected light is detected by a second photodetector having a detection region divided in the track direction; A first step of irradiating the second groove track with the sub-beam and detecting the reflected light by a third photodetector divided in the track direction; and an output signal from each region of the second photodetector And a second step of reading address information recorded on the first groove track by reading the difference signal.
The first sub-beam is irradiated to the first groove track adjacent to the land track irradiated with the main beam, and the second sub-beam is irradiated to the other second groove track. The reflected light from the optical recording medium by the first sub-beam is detected by a second photodetector whose detection area is divided in the track direction, and a difference signal of output signals from each area is generated. The address information is read by detecting.

According to a fourth aspect of the present invention, whether or not two groove tracks to be reproduced share the address information is based on a detection result of a difference signal obtained by subtracting an output signal from each region of the second photodetector. Further, a third step of discriminating is further added.
By monitoring the difference signal from each region detected by the second photodetector, that is, whether the wobble signal has been detected, it can be determined whether the main beam is a land track to be followed.
According to a fifth aspect of the present invention, there is provided an optical recording medium reproducing method for simultaneously reading information recorded on a land track and a groove track. The main beam emitted through an objective lens is adjacent to the land track and the land track of the optical recording medium. Irradiating the boundary region with the groove track to be irradiated, irradiating the land track adjacent to the boundary of the groove track with the first sub beam through the objective lens, and the second sub beam with the land through the objective lens. A first step of irradiating a groove track adjacent to the track boundary; and a detection region in which reflected light from the boundary region between the land track of the optical recording medium and the groove track adjacent thereto is divided into two in the track direction. And detecting the land track and the group by the first photodetector. A second step of detecting reflected light from the probe track by second and third photodetectors each having a detection region divided into two in the track direction; and from each detection region in the second or third photodetector. The third step of performing the tracking control based on the difference signal obtained by subtracting the output signal of, and the sum of the output signals from each detection region is RF, the difference between the output signals from each detection region is PP, the constant is C, When the information recorded on the first groove track is RF1 and the information recorded on the second groove track is RF2, the RF1 is calculated by RF1 = RF + C · PP, and the RF2 is RF2 = RF−. A fourth step of reading information recorded on the land track and the groove track by calculating with C · PP; It is characterized in.
If the difference signal of the second photodetector or the difference signal of the third photodetector is used as a tracking error signal, the center of the main beam can follow the boundary between the land track and the groove track.

According to a sixth aspect of the present invention, in the third step, a signal obtained by inverting the difference signal of the third photodetector is generated, and the signal and the difference signal of the second photodetector are added. Tracking control is performed.
If the light intensity of the sub-beam difference signal is not sufficient, the signal amplitude is increased by using the sum of the difference signal of the first sub-beam and the signal obtained by inverting the difference signal of the second sub-beam as the tracking error signal. Therefore, more stable tracking control can be performed.
According to a seventh aspect of the present invention, there is provided irradiation means for irradiating a main beam emitted through an objective lens so as to include a land track of an optical recording medium and first and second groove tracks adjacent to the land track, and the light Area detection means for detecting the amount of reflected light from the recording medium by a first detector having at least a detection area divided into two in the track direction, and the sum of the output signals from each of the detection areas is RF, and from each of the detection areas The output signal difference is PP, the constant is C, the signal from the pit or mark recorded on the first groove track is RF1, and the signal from the pit or mark recorded on the second groove track is In the case of RF2, the RF1 is calculated by RF1 = RF + C · PP, the RF2 is calculated by RF2 = RF−C · PP, and the first And an information reading means for reading information recorded on the second groove track, wherein the first and second groove tracks of the optical recording medium are independent spiral shapes. An optical recording medium having a double spiral structure formed as a track and having address information recorded as wobble on the first groove track, the first groove track being irradiated with the first sub beam. A first irradiating means; a first detecting means for detecting reflected light from the first groove track by a second photodetector having a detection region divided in the track direction; and a second sub-beam, Second irradiating means for irradiating the second groove track, and third light detection in which the reflected light from the second groove track is divided in the track direction A second detection means for detecting the difference, a difference signal generation means for generating a difference signal obtained by subtracting an output signal from each region of the second photodetector, and the first groove by reading the difference signal. Address reading means for reading address information recorded on the track.
The present invention has the same effect as that of the third aspect.

According to the eighth aspect of the present invention, whether or not two groove tracks to be reproduced share address information is determined based on a detection result of a difference signal obtained by subtracting an output signal from each region of the second photodetector. It further comprises a discrimination means for discriminating.
The present invention has the same effect as that of the fourth aspect.
9. An optical recording medium reproducing apparatus for simultaneously reading information recorded on a land track and a groove track, wherein the main track and the groove track adjacent to the land track via the objective lens by the main beam. Boundary irradiation means for irradiating the boundary area between the first and second regions, land track irradiation means for irradiating a land track adjacent to the boundary of the groove track via the objective lens, and a second sub beam for the objective lens. A groove track irradiating means for irradiating a groove track adjacent to the boundary of the land track through the optical disk, and the reflected light from the boundary area between the land track of the optical recording medium and the groove track adjacent thereto is divided into two in the track direction. Detected by a first photodetector having a defined detection area First detection means; second detection means for detecting reflected light from the land track and groove track by second and third photodetectors each having a detection region divided into two in the track direction; Tracking control means for performing tracking control based on a difference signal obtained by subtracting an output signal from each detection region in the second or third photodetector, and a sum of output signals from the first detection region is RF, The difference in output signal from the first detection area is PP, the constant is C, the signal from the pit or mark recorded in the first groove track is RF1, and the pit is recorded in the second groove track Alternatively, when the signal from the mark is RF2, the RF1 is calculated by RF1 = RF + C · PP, and the RF2 is calculated by RF2 = RF−C · PP. A calculation means for calculation for, characterized by comprising a reading means for reading the information recorded on the land track and groove track.
The present invention has the same effect as that of the fifth aspect.
The tenth aspect of the present invention provides an inverted signal generating unit that generates a signal obtained by inverting the difference signal of the third photodetector, a signal generated by the inverted signal generating unit, and a difference signal of the second photodetector. And a tracking control means for performing tracking control based on the signal generated by the addition signal means.
The present invention has the same effect as that of the sixth aspect.

According to the first aspect of the present invention, since the groove track has a double spiral structure, the information recorded on the first and second groove tracks can be continuously recorded without jumping the track every rotation of the recording medium. Simultaneous playback is possible.
Further, since the address information is shared by the first and second groove tracks, the address information can be reproduced even at a narrow track pitch.
According to the third aspect of the present invention, since the first sub beam is irradiated to the wobbled first groove track, the address information can be read from the detection signal of the reflected light.
According to the fourth aspect of the present invention, since it is determined whether or not the wobble signal has been detected from the difference signal of the second photodetector, it can be determined whether or not the main beam is a land track to be followed.
According to the fifth aspect of the present invention, since the main beam is irradiated on the boundary between the land track and the groove track and the two tracks are reproduced simultaneously, the tracks are recorded on the land track and the groove track without jumping each time the recording medium is rotated. Can be played back simultaneously.
Further, in claim 6, since the sum of the difference signal of the first sub-beam and the signal obtained by inverting the difference signal of the second sub-beam is used as a tracking error signal, a sufficient signal amplitude can be obtained and stable tracking control can be performed. It can be carried out.
According to the seventh aspect of the present invention, since the groove track has a double spiral structure, information recorded on the first and second groove tracks is continuously reproduced simultaneously without performing a track jump every rotation of the recording medium. be able to.
Further, in the eighth aspect, since it is determined whether or not the wobble signal is detected from the difference signal of the second photodetector, it is possible to determine whether or not the main beam is a land track to be followed.
According to the ninth aspect of the invention, since the main beam is applied to the boundary between the land track and the groove track and the two tracks are reproduced simultaneously, the information recorded on the land track and the groove track without jumping the track every rotation of the recording medium. Can be reproduced simultaneously.
Further, in claim 10, since the sum of the difference signal of the first sub-beam and the signal obtained by inverting the difference signal of the second sub-beam is used as a tracking error signal, a sufficient signal amplitude can be obtained and stable tracking control can be performed. It can be carried out.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
First, the gist of the present invention will be described. In order to solve the conventional problems, the present inventors have invented a reproduction method capable of improving the data transfer rate without increasing the reproduction linear velocity. It irradiates one light spot so as to include two adjacent tracks, detects the reflected light from the optical recording medium with a photodetector having a plurality of detection areas, and calculates the output signal of each detection area In this way, the information recorded on each track is reproduced. According to this reproduction method, the pits or marks that are simultaneously read may not be aligned in the radial direction. Therefore, information recorded on two adjacent tracks can be separated and reproduced without considering the positional accuracy of the pits or marks in the radial direction during recording. The method of separating the signals from each track uses the following equation.
RF1 = (IA + IB + IC + ID) + C · (IA + IB−IC−ID) (1)
RF2 = (IA + IB + IC + ID) −C · (IA + IB−IC−ID) (2)
Here, RF1 is a signal from the pit of the track 1 (hereinafter referred to as Tr1), RF2 is a signal from the pit of the track 2 (hereinafter referred to as Tr2), C is a constant, and IA to ID are detections of the detectors. Signals from regions A to D.
Although the data transfer rate at the time of reproduction is improved by the above reproducing method, a track jump occurs every time the recording medium rotates as shown in FIG. An area 42 that cannot be reproduced is generated because it takes a certain time from the jump to the next track until the information of the track is reproduced. If this area is set as a gap area where recording / reproduction is not performed, the problem can be solved. However, if a gap area is provided for each track, recording capacity will be reduced.
The optical recording medium of the present invention irradiates the main beam to the land track and the first and second groove tracks adjacent thereto, and detects the reflected light from the optical recording medium by a photodetector having a plurality of detection regions. An optical recording medium that reproduces information recorded on each groove track by calculating the output signal of each detection area, and the first and second groove tracks are formed by independent spirals. Due to the double spiral structure, the main beam can follow the land track without causing a track jump every rotation of the optical recording medium, so that information recorded on the first and second groove tracks can be reproduced simultaneously. it can.

FIG. 1 is an enlarged view of an optical recording medium substrate having a double spiral structure according to a first embodiment of the present invention. Information is recorded on the first groove track 1 and the second groove track 2. The main beam is applied to the land track 4 between the first and second groove tracks 1 and 2 as indicated by a dotted line 3 in FIG. The condensing position of the main beam on the land track 4a reaches the second land track 4b when the optical recording medium makes one rotation, so that the first and second groove tracks 1 are continuously recorded without performing a track jump. 2 can be reproduced simultaneously.
FIG. 2 is a diagram for explaining address information. The address information is shared between the first and second groove tracks 1 and 2 as shown in FIG. 2, and the first groove track 1 is recorded by wobbling the groove in the radial direction according to the address information. The second groove is a straight groove. The first groove beam 1 adjacent to the land track irradiated with the main beam MB is irradiated with the first sub beam SB1, and the other second groove track 2 is irradiated with the second sub beam SB2.
FIG. 3 is a diagram showing a positional relationship among a plurality of detectors. The reflected light from the optical recording medium by the first sub-beam SB1 is detected by the second photodetector 11 in which the detection region shown in FIG. 3 is divided in the track direction, and output signals IA2 and IB2 from the regions A2 and B2 are detected. And the address information is read by detecting the difference signal. Further, by monitoring this difference signal, that is, whether or not the wobble signal has been detected, it can be determined whether or not the main beam MB is a land track to be followed.
In order to simultaneously reproduce information recorded on the first and second groove tracks 1 and 2 of this optical recording medium, the following method is used. The main beam MB is irradiated so as to include a land track and two adjacent groove tracks, and the reflected light from the optical recording medium is detected by the photodetector 10 having a plurality of detection regions. In this method, the information recorded in each track is reproduced by arithmetically processing the output signals IA and IB from the area B according to the equations (1) and (2).
RF1 = (IA + IB) + C (IA-IB) (3)
RF2 = (IA + IB) -C (IA-IB) (4)
Here, RF1 is a signal from the second groove track, RF2 is a signal from the first groove track, and C is a constant. By this method, two main tracks MB can be reproduced simultaneously and continuously without a track jump by using one main beam MB without using multiple beams.

Next, examples of the present invention will be described. As the optical recording medium, a phase change optical disc capable of recording with a laser beam having a wavelength of 405 nm and an objective lens NA of 0.65 was used. The substrate is made of polycarbonate having a diameter of 120 mm and a thickness of 0.6 mm, and a double spiral groove track is formed on the substrate surface by injection molding. On this substrate, a dielectric film, a phase change recording film mainly composed of Ge—Sb—Te, a dielectric film, and a reflective film were sequentially laminated to produce a phase change optical disk.
FIG. 4 is a diagram showing a track configuration of the recording medium according to the embodiment of the present invention. The same components will be described with the same reference numerals. As shown in FIG. 4, repetitive data 20 having a mark and space length of 0.30 μm is recorded on the first groove track 1 of this optical recording medium, and a mark and space length of 1.0 μm is recorded on the second groove track 2. Repeat data 21 was recorded. The main track MB is irradiated to the land track 4 between the first and second groove tracks 1 and 2 and the reflected light is detected by the photodetector 10 in which the detection areas are divided into A and B. The output signals IA and IB in the areas A and B were sampled with a digital oscilloscope.
FIG. 5 is a diagram illustrating RF2 and RF1 as a result of calculating Expressions (3) and (4) using the sampling results of IA + IB, IA +, and IB. From FIG. 5, the first and second groove tracks 1 and 2 are simultaneously irradiated with the main beam MB, and the detection results of the reflected light are calculated as follows by calculating Equations (3) and (4). It was confirmed that the information recorded on the second groove tracks 1 and 2 could be taken out.
The reproducing method of the optical recording medium according to the second embodiment of the present invention is a method applied to a land and groove recording method for recording information on land tracks and groove tracks, and as shown in FIG. The beam 25 is irradiated to the boundary between the land track 26 and the groove track 27 adjacent thereto, and the reflected light from the optical recording medium is detected by a photodetector in which the detection area is divided in the track direction, and the output of each detection area This is a method of reading information recorded on the land track 26 and the groove track 27 by performing arithmetic processing on the signal. As can be seen from the trajectory of the main beam indicated by the dotted line in FIG. 6, the main beam 25 is made to follow the boundary between the land track 26 and the groove track 27 so that the track jump does not occur every rotation of the optical recording medium. Thus, the information recorded on the land track and the groove track can be reproduced simultaneously.

FIG. 7 is an enlarged view of a land and groove recording type optical recording medium substrate. The same components will be described with the same reference numerals. The main beam MB is applied to the boundary between the land track 26 and the groove track 27, and the first sub beam SB1 is applied to the center of the groove track 27 that is separated from the center of the main beam MB in the quarter radial direction of the track pitch. The second sub beam SB2 is applied to the center of the land track 26 which is separated in the opposite direction by the same distance as the first sub beam SB1. Reflected light from the optical recording medium by the main beam MB and the first and second sub beams SB1 and SB2 is detected by photodetectors whose detection areas are divided in the track direction, respectively.
FIG. 8 is a diagram showing a difference signal output from each photodetector when the main beam and the sub beam cross the land and groove tracks. 8 (1) is a cross-sectional view of the optical recording medium, FIG. 8 (2) is a difference signal of the first photodetector, FIG. 8 (3) is a difference signal of the second photodetector, and FIG. 8 (4). Is the difference signal of the third photodetector. Comparing the sectional view of the optical recording medium with the difference signal of each photodetector, the difference signal of the second photodetector in FIG. 8 (3) or the difference signal of the third photodetector in FIG. 8 (4). Is used as a tracking error signal, it can be seen that the center of the main beam can follow the boundary between the land track and the groove track. If the light intensity of the sub-beam difference signal is not sufficient, the signal amplitude is increased by using the sum of the difference signal of the first sub-beam and the signal obtained by inverting the difference signal of the second sub-beam as the tracking error signal. Therefore, more stable tracking control can be performed.

FIG. 9 is a block diagram showing an example of an optical recording medium recording / reproducing apparatus of the present invention. The same components will be described with the same reference numerals. The recording / reproducing apparatus 100 includes a spindle motor 31 that supports and rotates the optical recording medium 30, and an optical pickup that irradiates the optical recording medium 30 with the light beam and detects the reflected light beam for photoelectric conversion. 32, photodetectors 10, 11, and 12 that detect the amount of reflected light from the optical pickup 32, a signal control unit 13 that performs arithmetic processing on output signals from the photodetectors 10, 11, and 12, and a signal processing result 13 are stored. And a memory 35.
The signal control unit 13 outputs a recording signal based on the recording data to the laser driving circuit 34, and the laser driving circuit 34 drives the laser light source of the optical pickup 32 accordingly to record the data. The signal control unit 13 generates a track error signal, a focus error signal, and a wobble signal from output signals from the photodetectors 10, 11, and 12.

As described above, according to the present invention, since the groove tracks 1 and 2 have a double spiral structure, they are recorded on the first and second groove tracks 1 and 2 without performing track jump every rotation of the recording medium. Can be played back simultaneously.
Since the address information is shared by the first and second groove tracks 1 and 2, the address information can be reproduced even at a narrow track pitch.
Further, since the first sub beam SB1 is irradiated to the wobbled first groove track 1, the address information can be read from the detection signal of the reflected light.
Further, since it is determined whether or not the wobble signal has been detected from the difference signal of the second photodetector 11, it can be determined whether or not the main beam MB is a land track to be followed.
In addition, since the main beam MB is applied to the boundary between the land track 4 and the groove tracks 1 and 2 and two tracks are reproduced simultaneously, the land track 4 and the groove track 1, 2 can be reproduced simultaneously and continuously.
Further, since the sum of the difference signal of the first sub-beam SB1 and the signal obtained by inverting the difference signal of the second sub-beam SB2 is used as a tracking error signal, a sufficient signal amplitude is obtained and stable tracking control is performed. Can do.
In addition, since the groove track has a double spiral structure, information recorded on the first and second groove tracks 1 and 2 can be reproduced simultaneously and continuously without jumping the track every rotation of the recording medium. Can do.
Further, since it is determined whether or not the wobble signal is detected from the difference signal of the second photodetector 11, it is possible to determine whether or not the main beam is a land track to be followed.

1 is an enlarged view of an optical recording medium substrate having a double spiral structure according to a first embodiment of the present invention. It is a figure explaining address information. It is a figure which shows the positional relationship of a some detector. It is a figure which shows the track structure of the recording medium based on the Example of this invention. It is a figure which shows RF2 and RF1 of the result of calculating Formula (3) and Formula (4) using the sampling result of IA + IB, IA +, and IB. It is an enlarged view of an optical recording medium substrate having a double spiral structure according to a second embodiment of the present invention. FIG. 2 is an enlarged view of a land & groove recording type optical recording medium substrate. It is a figure which shows the difference signal output from each photodetector, when a main beam and a sub beam cross a land and a groove track. It is a block diagram which shows an example of the optical recording medium recording / reproducing apparatus of this invention. It is a figure which shows the mode of the conventional track jump.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10, 11, 12 Photo detector, 13 Signal control part, 30 Optical recording medium (optical disk), 31 Spindle motor, 32 Optical pick-up, 33 Feed motor, 34 Laser drive circuit, 35 Memory, 100 Recording / reproducing apparatus

Claims (10)

  The main beam emitted through the objective lens is irradiated so as to include the land track of the optical recording medium and the first and second groove tracks adjacent to the land track, and the amount of light reflected from the optical recording medium is at least Detection is performed by a detector having a detection region divided into two in the track direction, the sum of the output signals from each detection region is RF, the difference between the output signals from each detection region is PP, the constant is C, and the first When the information recorded on the groove track is RF1 and the information recorded on the second groove track is RF2, the RF1 is calculated by RF1 = RF + C · PP, and the RF2 is RF2 = RF−C · PP. In the optical recording medium that reads the information recorded in the first and second groove tracks, the first Preliminary second groove track, the optical recording medium, which is a double spiral structure formed as an independent spiral track.   Either one of the first and second groove tracks is recorded by meandering in a radial direction corresponding to the address information, and the address information is shared by the adjacent first and second groove tracks. The optical recording medium according to claim 1. The main beam emitted through the objective lens is irradiated so as to include the land track of the optical recording medium and the first and second groove tracks adjacent to the land track, and the amount of light reflected from the optical recording medium is at least Detection is performed by a detector having a detection region divided into two in the track direction, the sum of the output signals from each detection region is RF, the difference between the output signals from each detection region is PP, the constant is C, and the first When the information recorded on the groove track is RF1 and the information recorded on the second groove track is RF2, the RF1 is calculated by RF1 = RF + C · PP, and the RF2 is RF2 = RF−C · PP. In the reproducing method of the optical recording medium for detecting the information recorded on the first and second groove tracks by calculating
The first and second groove tracks of the optical recording medium have a double spiral structure formed as independent spiral tracks, and the address information is recorded as wobble on the first groove track. A recording medium, wherein the first sub-beam is irradiated to the first groove track, the reflected light is detected by a second photodetector having a detection region divided in the track direction, and the second sub-beam is detected. A first step of irradiating the second groove track and detecting the reflected light by a third photodetector divided in the track direction;
And a second step of reading address information recorded on the first groove track by reading a difference signal of output signals from each region of the second photodetector. Media playback method.   Whether or not two groove tracks to be reproduced share the address information is determined based on the detection result of the difference signal obtained by subtracting the output signal from each region of the second photodetector. 4. The method of reproducing an optical recording medium according to claim 3, further comprising a step. In a method for reproducing an optical recording medium that simultaneously reads information recorded on a land track and a groove track,
The main beam emitted through the objective lens irradiates the boundary region between the land track of the optical recording medium and the groove track adjacent to the land track, and the first sub beam is emitted through the objective lens to the groove track. Irradiating a land track adjacent to the boundary of the first track, and irradiating a groove track adjacent to the boundary of the land track through the objective lens with a second sub beam;
Reflected light from a boundary region between a land track of the optical recording medium and a groove track adjacent thereto is detected by a first photodetector having a detection region divided into two in the track direction, and the land track and groove A second step of detecting reflected light from the track by second and third photodetectors each having a detection region divided into two in the track direction;
A third step of performing tracking control based on a difference signal obtained by subtracting an output signal from each detection region in the second or third photodetector;
The sum of the output signals from each detection area is RF, the difference between the output signals from each detection area is PP, the constant is C, the information recorded in the first groove track is RF1, and the second groove track is When the recorded information is RF2, the RF1 is calculated by RF1 = RF + C · PP, and the RF2 is calculated by RF2 = RF−C · PP, thereby being recorded on the land track and groove track. A method for reproducing an optical recording medium, comprising: a fourth step of reading information. In the third step,
The tracking control is performed based on a signal obtained by generating a signal obtained by inverting the difference signal of the third photodetector and adding the difference signal of the second photodetector. 5. A method for reproducing an optical recording medium according to 5. Irradiation means for irradiating a main beam emitted through the objective lens so as to include a land track of the optical recording medium and first and second groove tracks adjacent to the land track, and reflection from the optical recording medium An area detection means for detecting the amount of light by a first detector having a detection area divided into at least two in the track direction, the sum of the output signals from each detection area is RF, and the difference between the output signals from each detection area Is PP, the constant is C, the signal from the pit or mark recorded in the first groove track is RF1, and the signal from the pit or mark recorded in the second groove track is RF2, The RF1 is calculated by RF1 = RF + C · PP, the RF2 is calculated by RF2 = RF−C · PP, and the first and second groups are calculated. And information reading means for reading information recorded on Butorakku, in the reproduction apparatus for an optical recording medium having a,
The first and second groove tracks of the optical recording medium have a double spiral structure formed as independent spiral tracks, and the address information is recorded as wobble on the first groove track. A recording medium, a second irradiating means for irradiating the first groove track with a first sub-beam, and a detection area in which reflected light from the first groove track is divided in the track direction. A first detecting means for detecting by the photodetector, a second irradiating means for irradiating the second groove track with the second sub-beam, and a reflected light from the second groove track in the track direction. Second detection means for detecting by the third photodetector, and difference signal generation means for generating a difference signal by subtracting an output signal from each region of the second photodetector. , Reproducing apparatus for an optical recording medium, characterized in that and an address reading means for reading the address information recorded on the first groove track by reading the difference signal.   Discriminating means for discriminating whether or not two groove tracks to be reproduced share address information based on a detection result of a difference signal obtained by subtracting an output signal from each region of the second photodetector. The optical recording medium reproducing device according to claim 7, further comprising: In an optical recording medium reproducing device that simultaneously reads information recorded on a land track and a groove track,
Boundary irradiating means for irradiating a boundary region between a land track of the optical recording medium and a groove track adjacent to the land track by the main beam emitted through the objective lens, and a first sub beam through the objective lens Land track irradiation means for irradiating a land track adjacent to the boundary of the groove track; Groove track irradiation means for irradiating a groove track adjacent to the boundary of the land track through the objective lens with a second sub beam;
First detection means for detecting reflected light from a boundary region between a land track of the optical recording medium and a groove track adjacent thereto by a first photodetector having a detection region divided in two in the track direction; Second detection means for detecting reflected light from the land track and groove track by second and third photodetectors each having a detection region divided into two in the track direction;
Tracking control means for performing tracking control based on a difference signal obtained by subtracting an output signal from each detection region in the second or third photodetector;
The sum of the output signals from the first detection area is RF, the difference between the output signals from the first detection area is PP, the constant is C, and from the pit or mark recorded in the first groove track When the signal is RF1 and the signal from the pit or mark recorded on the second groove track is RF2, the RF1 is calculated by RF1 = RF + C · PP, and the RF2 is calculated by RF2 = RF−C · PP. A calculation means for calculating;
An optical recording medium reproducing apparatus, comprising: a reading unit that reads information recorded on the land track and the groove track.   Inverted signal generating means for generating a signal obtained by inverting the difference signal of the third photodetector, and a signal obtained by adding the signal generated by the inverted signal generating means and the difference signal of the second photodetector 10. An optical recording medium reproducing apparatus according to claim 9, further comprising: an addition signal unit that generates a tracking signal; and a tracking control unit that performs tracking control based on a signal generated by the addition signal unit.

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