WO2001015149A1

WO2001015149A1 - Optical recording medium and direction detector

Info

Publication number: WO2001015149A1
Application number: PCT/JP2000/005662
Authority: WO
Inventors: Eiji Ueda; Yasumori Hino; Takashi Inoue
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 1999-08-24
Filing date: 2000-08-23
Publication date: 2001-03-01

Abstract

A plurality of servo regions (110) and data regions (120) are alternately arranged along the track center line (102), and the servo regions (110) are each provided with a clock mark (111), a first wobble mark (112) and a second wobble mark (113). The plurality of servo regions (110) constitute a plurality of servo pattern regions (110a to d) radially disposed in a repeated sequence. The plurality of servo pattern regions (110a to d) differ from one another in at least one arrangement selected from an arrangement of the first wobble mark (112) with respect to the clock mark (111) and an arrangement of the second wobble mark (112) with respect to the clock mark (111). The above configuration can easily and accurately detect the relative moving direction of a light spot with respect to an optical recording medium.

Description

Description Optical recording medium and direction detection device

The present invention relates to an optical recording medium for recording and reproducing information using light, and a direction detecting device using the optical recording medium. Background art

In recent years, optical recording media, such as CDs and DVDs, have been widely used as music and video storage media, and their capacity has been further increased. In order to increase the capacity, it is necessary to accurately control the tracking of the optical spot. As a method for performing tracking control, there is an optical recording medium using a sample servo tracking method. The sample servo tracking method is a method in which tracking control is performed based on reproduction signals from servo areas dispersedly arranged on a disk.

An example of a conventional optical recording medium using the sample servo tracking method will be described below. FIG. 14 schematically shows a plan view of an example of the conventional optical recording medium 10. Referring to FIG. 14, a track center line 11 is spirally formed on a conventional optical recording medium 10. Servo areas and data areas are alternately arranged along the track center line 11. The configuration of the servo area 20 and the data area 30 is schematically shown in FIG. In the servo area 20, a clock mark 21, a first wobble mark 22 and a second wobble mark 23 are formed at predetermined intervals. In the data area 30, information is recorded substantially on the track center line 11. The clock mark 21 is composed of the first wobble mark 22 and the second This is a mark for generating a synchronous clock signal used for reproducing the wobble mark 23 and the information recorded in the data area 30. The track center line 11 is a virtual line that continuously connects the centers of the clock marks 21.

The first wobble mark 22 and the second wobble mark 23 are formed at positions radially offset from each other by a predetermined distance in the radial direction with respect to the track center line 11. The first wobble mark 22 and the second wobble mark 23 are a tracking error signal corresponding to the displacement of the optical spot irradiated on the optical recording medium 10 from the track center line 11. Used to detect.

When the light spot deviates from the track center line 11, the reflected light from the first wobble mark 22 or the second wobble mark 23 becomes larger than the other reflected light. In the optical recording medium 10, a tracking error signal can be detected using the difference between the reflected lights.

As described above, in the optical recording medium 10, the tracking error signal is detected based on the synchronous clock signal generated from the clock mark 21. Then, using the tracking error signal, the optical spot on the optical recording medium 10 performs tracking control so that the data information recorded in the data area 30 is accurately scanned, and information recording / reproduction is performed. Done.

However, with the ordinary optical recording medium 10, it is difficult to detect the relative movement direction in the radial direction between the optical recording medium 10 and the optical spot irradiated on the optical recording medium 10. This made it difficult to count the number of trucks being accessed.

To cope with this problem, a new optical disc has been proposed in Japanese Patent Application Laid-Open No. 63-225924. This optical disk is composed of a clock pit, which is a reference pit for information data and at least one pit of a pair of wobbly pits. The optical disk is characterized in that the distance from the optical disc is three or more predetermined steps, and the distance is repeatedly changed in a predetermined order for each of one or more information tracks.

According to this optical disk, it is possible to detect the direction during the access operation of the optical disk and to increase the track count resolution. However, in the above-mentioned conventional optical recording medium, the radial direction of the optical spot with respect to the optical recording medium is It has been found that when detecting the moving direction of the, a detection error may occur. For this reason, there was a problem that the accuracy at the time of access deteriorated. Disclosure of the invention

In order to solve the above-mentioned problems, the present invention provides an optical recording medium capable of detecting an accurate movement direction with respect to a radial relative movement between an optical spot irradiated on the optical recording medium and the optical recording medium, and It is intended to provide a direction detecting device.

In order to achieve the above object, an optical recording medium according to the present invention is a disk-shaped optical recording medium in which a plurality of servo areas and data areas are alternately arranged along a track center line, wherein the servo area includes a clock. A plurality of servo areas, each of which comprises a mark, a first wobble mark, and a second wobble mark, wherein the plurality of servo areas form a plurality of servo pattern areas repeatedly arranged in the radial direction in order; The regions differ from each other in at least one arrangement selected from the arrangement of the first wobble mark with respect to the clock mark and the arrangement of the second wobble mark with respect to the close mark. According to the optical recording medium, the relative movement in the radial direction between the optical recording medium and the optical spot irradiated on the optical recording medium is determined in the moving direction. Can be easily detected. Further, the number of tracks of the light spot moving in the radial direction can be easily counted.

In the above optical recording medium of the present invention, the plurality of servo pattern areas are mutually determined based on a distance between the clock mark and the first wobble mark and a distance between the click mark and the second wobble mark. At least one interval chosen may be different. According to the above configuration, the present invention can be easily applied to an optical recording medium in which the optical spot moves on the track center line at a constant linear velocity.

In the optical recording medium according to the present invention, the plurality of servo pattern areas may include a space between the clock mark and the first wobble mark or a distance between the clock mark and the first wobble mark, between two radially adjacent servo pattern areas. Either of the intervals with the second wobble mark may be substantially equal. According to the above configuration, the moving direction and the number of moving tracks of the light spot in the radial direction with respect to the optical recording medium can be particularly accurately detected.

In the optical recording medium according to the present invention, the plurality of servo pattern areas include a first servo pattern area, a second servo pattern area, a third servo pattern area, and a fourth servo pattern area, The first servo pattern area and the second servo pattern area have substantially equal intervals between the clock mark and the second servo mark area, and the second servo pattern area and the third servo pattern The area is substantially equal in interval between the clock mark and the first wobble mark, and the third servo pattern area and the fourth servo pattern area are equal to the clock mark and the second servo pattern area. The first servo pattern area and the fourth servo pattern area have substantially the same distance between the clock mark and the first wobble mark. It may be substantially equal the distance between. According to the above configuration, the length of the service area can be reduced, so that high-density information recording is possible. Thus, an efficient optical recording medium can be obtained.

In the optical recording medium, a plurality of the servo areas may be radially arranged, and a circumferential length of the servo area may be constant. According to the above configuration, the proportion of the area occupied by the service area can be reduced, so that an optical recording medium capable of recording information with high density can be obtained.

In the above optical recording medium, the plurality of servo pattern areas are formed from a center angle formed by the clock mark and the first wobble mark and a center angle formed by the clock mark and the second wobble mark. At least one selected central angle may be different. According to the above configuration, the present invention can be easily applied to an optical recording medium that records and reproduces information by rotating the optical recording medium at a constant rotational angular velocity.

In the optical recording medium, the plurality of servo pattern areas may include a central angle formed by the clock mark and the first pebble mark between two servo pattern areas radially adjacent to each other, or a center angle formed by the clock mark and the second servo mark area. May be substantially equal to each other. The optical recording medium, wherein the plurality of servo pattern areas include a first servo pattern area, a second servo pattern area, a third servo pattern area, and a fourth servo pattern area; The servo pattern area and the second servo pattern area have substantially the same center angle between the clock mark and the second wobble mark, and the second servo pattern area and the third servo pattern area have the same center angle. The servo pattern area has substantially the same central angle between the clock mark and the first pebble mark, and the third servo pattern area and the fourth servo pattern area have the clock mark and the second servo pattern area. The first servo pattern area and the fourth servo pattern area have substantially the same central angle formed by the double mark and the clock mark and the first double mark. Even if the central angles formed by Good.

Further, the direction detecting device of the present invention detects a relative moving direction in a radial direction between an optical recording medium and a light spot irradiated on the optical recording medium for reading information recorded on the optical recording medium. The optical recording medium comprises a servo area forming a plurality of servo pattern areas in which a clock pit, a first wobble pit, and a second wobble pit are formed. An optical recording medium according to the invention, comprising: a detection unit for detecting the clock mark; a timing signal generation unit for generating a timing signal in accordance with the clock mark detected by the detection unit; and using the timing signal. A position detecting means for detecting a position of the first wobble mark and a position of the second wobble mark and outputting a detection signal; An identification unit that identifies the type of the service area using the detection signal, and outputs an identification signal; and detects a relative movement direction of the optical spot and the optical recording medium in a radial direction from a change in the identification signal. And a direction signal generating means for outputting a direction signal. According to the direction detecting device, the moving direction can be easily detected with respect to the relative movement in the radial direction between the optical recording medium and the light spot. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view schematically showing one example of the optical recording medium of the present invention.

FIG. 2 is a plan view schematically showing a configuration of a servo area in the optical recording medium shown in FIG.

FIG. 3 is a diagram schematically showing the structure of the optical recording medium shown in FIG.

FIG. 4 shows another example of the servo area of the optical recording medium of the present invention. It is a top view shown typically.

FIG. 5 is a plan view schematically showing another example of the optical recording medium of the present invention.

FIG. 6 is a plan view schematically showing a configuration of a servo area in the optical recording medium shown in FIG.

FIG. 7 is a schematic diagram showing an example of the configuration of the direction detecting device of the present invention.

FIG. 8 is a schematic diagram showing an example of the operation of the double mark position detection circuit in the direction detection device of the present invention.

FIG. 9 is a schematic diagram showing another example of the operation of the double mark position detection circuit in the direction detection device of the present invention.

FIG. 10 is a schematic diagram showing another example of the operation of the double mark position detecting circuit in the direction detecting device of the present invention.

FIG. 11 is a schematic diagram showing another example of the operation of the double mark position detecting circuit in the direction detecting device of the present invention.

FIG. 12 is a diagram showing an example of the operation of the direction detecting device of the present invention.

FIG. 13 is a diagram showing another example of the operation of the direction detecting device of the present invention.

FIG. 14 is a plan view schematically showing an example of a conventional optical recording medium.

FIG. 15 is a schematic diagram showing an example of a servo area and a data area in a conventional optical recording medium. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. An optical recording medium according to the present invention is a disk-shaped optical recording medium in which a plurality of servo areas and data areas are alternately arranged along a track center line, and the servo area includes a clock mark and a first wobble mark. A plurality of servo regions are provided, and the plurality of servo regions constitute a plurality of servo pattern regions that are repeatedly arranged in the radial direction in order. The plurality of servo pattern areas differ from each other in at least one arrangement selected from the arrangement of the first wobble mark with respect to the clock mark and the arrangement of the second wobble mark with respect to the clock mark. In Embodiments 1 and 2, the optical recording medium of the present invention will be described with an example.

(Embodiment 1)

In the first embodiment, an example of the optical recording medium of the present invention will be described. In the optical recording medium 100 of the first embodiment, the arrangement of the click mark and the wobble mark is defined by the distance between them.

A plan view of the optical recording medium 100 is schematically shown in FIG. The optical recording medium 100 has a disk shape. The disc center 101 in FIG. 1 is a virtual point located at the center of the disc-shaped optical recording medium 100. In the center of the optical recording medium 100, a through hole 101h is formed. The optical recording medium 100 is provided with a virtual track center line 102 in a spiral shape.

In the optical recording medium 100, a plurality of servo areas 110 and data areas 120 are alternately arranged along a track center line 102. In FIG. 1, one servo area 110 and one data area 120 are indicated by oblique lines. Each of the servo area 110 and the data area 120 is arranged in a single track (one round) with about 500 to 300 pieces. The plurality of servo areas 110 and the plurality of data areas 120 are arranged at the same angle in all tracks. In this case, multiple servo areas 110 and multiple data The overnight area 120 is arranged almost radially. Optical recording medium 100

The circumferential length of all servo areas 110 is constant.

The track center line 102 is a virtual line along which the optical spot should move when reading data recorded on the optical recording medium 100. The servo area 110 is an area for mainly performing tracking control. The data overnight area 120 is an area for recording and reproducing information. The servo area 110 forms a plurality of servo pattern areas having different arrangement patterns of the pebble marks. FIG. 2 schematically shows an example of a specific configuration in the case where the servo area 110 includes four servo pattern areas. In FIG. 2, the horizontal direction indicates the circumferential direction of the optical recording medium 100, and the vertical direction indicates the radial direction of the optical recording medium 100. Light spot L S is an optical recording medium

Move in the direction of the arrow with respect to 100.

Each servo area 110 includes a clock mark 111, a first wobble mark 112, and a second wobble mark 113. The servo area 110 shares one of the first and second wobbled marks 112 and 113 with the servo area 110 of a radially adjacent track. Therefore, in the optical recording medium 100, tracks 102a and tracks 102b having different polarities of the tracking error signal are alternately arranged in the radial direction.

The clock mark 1 1 1 is formed on the track center line 102.

It is used to generate a synchronous clock signal used for reproducing the information recorded in the data area 112 and the information recorded in the data area 120. The first wobbled mark 112 and the second wobbled mark 113 are pairs and are used for detecting a tracking error. The first wobbled mark 1 1 2 and the second wobbled mark 1 1 3 are opposite to each other across the track center line 102 by a half track pitch. It is located at a shifted position. Note that the track pitch is a distance between radially adjacent tracks, for example, 0.6 m.

As shown in FIG. 2, the plurality of servo areas 110 constitute a plurality of servo pattern areas 110a to 110d repeatedly arranged in the radial direction. Further, the support pattern areas 110 a to d are mutually spaced apart from each other by an interval between the clock mark 111 and the first wobbled mark 112, and between the clock mark 111 and the second wobbled mark 111. At least one interval selected from the intervals between and is different.

More specifically, in the optical recording medium 100, the servo area 1 1 0 A, the first servo pattern area 1 10a, the second servo pattern area 1 110b, third servo pattern area 110c, fourth servo pattern area 110d, first servo pattern area 110a, second servo pattern area 110 It is arranged repeatedly in the order of b · · ·. The first servo pattern area 110a is formed over n1 tracks in the radial direction (nl is, for example, a natural number of 30 or less, preferably 15 to 25). The second servo pattern area 110b is formed over n2 tracks (n2 is, for example, preferably a natural number of 30 or less, preferably 15 to 25). The third servo pattern area 110c is formed over n3 tracks (n3 is, for example, a natural number of 30 or less, preferably 15 to 25). The fourth support pattern area 110d is formed over n4 tracks (n4 is, for example, a natural number of 30 or less, preferably 15 to 25). In all the first servo pattern areas 110a, n1 may be the same or n1 may be changed according to the distance from the disk center (n2, n3 and n4 The same is true for.). Also nl ~! 14 may be the same or different. The above nl, n2, n3, and n4 can be determined according to the expected magnitude of the relative movement between the optical recording medium and the optical spot (the same applies to the following embodiments). . In other words, when the relative movement in the radial direction is large, n 1 to n 4 are preferably large, and when the relative movement in the radial direction is small, n 1 to n 4 is smaller. Is preferred. Specifically, the sum of nl, n2, n3 and n4 is preferably 100 or less. FIG. 2 shows a case where nl = 3, n2 = 5, n3 = 3, and n4 = 5 as an example.

Here, as shown in FIG. 2, the clock marks 111 formed in the servo pattern areas 110a to 110d are referred to as clock marks 111a to d, respectively. Similarly, the first wobbled mark 112 and the second wobbled mark 113 formed in the servo pattern area 110a to d are respectively replaced with the first wobbled mark 112 and the second wobbled mark 112. Wobble mark 1 1 3 a to d.

Further, as shown in FIG. 2, the intervals between the clock marks 111 a to d and the first double marks 112 a to d are L 1 a to L 1 d, respectively. The intervals between the clock marks 111 a to d and the second pebble marks 113 a to d are L 2 a to L 2 d, respectively. At this time, they satisfy the following relationship.

That is, the first servo pattern area 110a and the second servo pattern area 110b are substantially equal in distance between the clock mark 111 and the second double mark 113 (L2 a ^ L 2 b). Also, the distance between the clock mark 111 and the first double mark 111 is substantially equal between the second servo pattern area 110b and the third servo pattern area 110c (L 1b = Llc). Further, the third servo pattern area 110c and the fourth servo pattern area 110d are defined by the clock mark 111 and the second servo pattern area. The distance from the mark 1 1 3 is approximately equal (L 2 c L 2 d). In addition, the distance between the click mark 1 1 1 and the first double mark 1 1 2 is approximately equal between the first servo pattern area 110a and the fourth servo pattern area 110d. 1 a = L 1 d).

As described above, the first wobble mark 112 and the second wobble mark 113 can take two types of arrangements, each having a different distance from the click mark 111. Further, at least one arrangement selected from the arrangement of the first wobbled marks 112 and the arrangement of the second wobbled marks 113 differs from each other in the servo pattern areas 110a to 110d.

Next, the structure of the optical recording medium 100 will be described. FIG. 3 schematically shows a partial cross-sectional view of the optical recording medium 100 along the line XX (on the track center line 102). Referring to FIG. 3, the optical recording medium 15 1 includes a substrate 15 1, a layer 15 2 formed on the substrate 15 1, and a protective layer 15 3 formed on the layer 15 2. And

Light for recording and reproducing information is generally applied from the substrate 15 1 side. The clock mark 11 1, the first wobbled mark 112, and the second wobbled mark 113 are formed as recesses (pre-pits) on the substrate 151. The mark can be of various shapes. Note that the clock mark 111 may be any mark as long as it can generate a synchronous clock signal. For example, when a groove (pre-group) is formed in the substrate 151 located in the data area 120, the edge of the groove may be used as a clock mark.

As the substrate 151, for example, a substrate made of a transparent resin such as a polycarbonate resin or a polyolefin resin can be used. For the protective layer 153, for example, an ultraviolet curing resin such as an epoxy ultraviolet curing resin or a urethane ultraviolet curing resin can be used. Layer 1 5 2 is optical recording Various layers can be used depending on the type of the medium, and there is no particular limitation. For example, in the case of a read-only optical recording medium, a layer made of a metal such as aluminum can be used. In the case of an optical recording medium on which information can be recorded, a layer made of a write-once type recording material, a phase change type recording material, or a magnetic recording type recording material can be used.

The substrate 151 can be formed by, for example, an injection molding method or a photopolymer method. The layer 152 can be formed by, for example, an evaporation method or a sputtering method according to a material to be formed. The protective layer 153 can be formed by using, for example, a spin coating method.

In the optical recording medium 100, the distance between the clock mark and the pebble mark is different for each servo pattern area. For this reason, as described in Embodiment 3, with respect to the relative movement in the radial direction between the optical recording medium 100 and the light spot irradiated on the optical recording medium 100, the moving direction of the optical spot is changed. Can be detected.

In the optical recording medium 100, the circumferential length of the servo area 110 is constant regardless of the distance from the disk center 101. As a result, the ratio of the area occupied by the servo area 110 in the outer peripheral portion decreases, and the area occupied by the data area 120 increases. Therefore, in the optical recording medium 101, the data recording capacity can be increased.

Further, in the optical recording medium 100, an interval between the clock mark 111 and the first double mark 112 or a clock mark 111 between two radially adjacent servo pattern areas. Either of the intervals between 1 and the second wobble mark 1 13 is substantially equal. In other words, between two radially adjacent servo pattern regions, only one of the arrangement of the first wobbled mark 112 and the arrangement of the second wobbled mark 113 changes. According to this configuration, near the boundary between two radially adjacent servo pattern areas. Even when a light spot passes by the side, information from one of the two servo pattern areas can be obtained. Therefore, according to the optical recording medium 100, the movement direction of the optical spot can be detected particularly accurately. Between the two radially adjacent servo pattern areas, the first and second wobbled marks 1 can be detected. FIG. 4 shows the configuration of the servo area 110 m in the case where both 12 and 11 are changed. The servo area 110m in FIG. 4 includes three servo pattern areas 110ac. Between the servo pattern area 110a and the servo pattern area 110c, both the arrangement of the first double mark 112 and the arrangement of the second double mark 113 change. At this time, a region 110n that does not belong to any servo pattern region is generated at the boundary between the servo pattern region 110a and the servo pattern region 110c. Therefore, in the servo area 110 m, ambiguity may occur in the detection of the moving direction of the optical spot. On the other hand, in the optical recording medium 100 shown in FIG. 2, there is no ambiguity in the servo pattern area, and the moving direction of the optical spot can be accurately detected.

(Embodiment 2)

In Embodiment 2, another example of the optical recording medium of the present invention will be described. The optical recording medium 200 according to the second embodiment differs from the optical recording medium 100 according to the first embodiment only in the configuration of the servo area, and therefore, duplicate description may be omitted. In the optical recording medium 200, the arrangement of the clock mark and the arrangement of the wobbled mark are defined by the central angle between them.

A plan view of the optical recording medium 200 is schematically shown in FIG. The optical recording medium 200 has a disk shape. The disc center 201, the through hole 201h, and the track center line 202 are the same as the disc center 101, the through hole 101h, and the track center line 102, respectively. In the optical recording medium 200, a plurality of servo areas 210 and data areas 220 are alternately arranged along a track center line 202. Each of the servo area 210 and the data area 220 is arranged with about 500 to 300 pieces on one track (one round). The plurality of servo areas 210 and the plurality of data areas 220 are arranged at the same angle in all tracks. That is, a plurality of servo areas 210 and a plurality of data areas 220 are radially and alternately arranged. In the optical recording medium 200, the center angle formed by both ends of each of the service areas 210 is constant in all areas. Therefore, the circumferential length of the servo area 210 becomes longer toward the outer circumference. The servo area 210 is an area for mainly performing tracking control. The data area 220 is an area for recording and reproducing information. The servo area 210 forms a plurality of servo pattern areas having different arrangement patterns of the pebble marks. FIG. 6 schematically shows an example of a specific configuration in the case where the servo area 210 has four servo pattern areas.

Each servo area 2 10 includes a clock mark 2 21, a first wobble mark 2 22 and a second wobble mark 2 23. Note that the servo area 210 shares one of a pair of pebble marks between the servo areas 210 of the tracks adjacent in the radial direction. Therefore, in the optical recording medium 200, tracks 202a and tracks 202b having different tracking error signal polarities are alternately arranged in the radial direction.

The click mark 2 2 1 is the same as the clock mark 1 2 1.

The pair of wobble marks is used to detect a tracking error. The first and second wobbled marks 2 2 2 and 2 2 3 are halved in opposite directions with respect to the track center line 202. They are arranged at positions shifted by the pitch.

As shown in FIG. 6, the plurality of servo regions 210 constitute a plurality of servo pattern regions 210a to 210d repeatedly arranged in the radial direction. Then, the servo pattern areas 2110 a to d are respectively formed by the center angle formed by the clock mark 2 21 and the first wobble mark 222, and the clock mark 2 21 and the second wobble mark 2 2 3 At least one central angle selected from the central angles formed by the two is different.

More specifically, in the optical recording medium 200, the servo area 210, the first servo pattern area 210a, and the second servo pattern area from the inner circumference to the outer circumference of the disk. 210b, third servo pattern area 210c, fourth servo pattern area 210d, first servo pattern area 210a, second servo pattern area 210b It is arranged repeatedly in the order of · ·. The first servo pattern area 210a is formed over the m1 tracks in the radial direction (m1 is, for example, a natural number of 30 or less, preferably 15 to 25). The second servo pattern area 210b is formed over m2 tracks (m2 is, for example, preferably a natural number of 30 or less, preferably 15 to 25). The third servo pattern area 210c is formed over m3 tracks (m3 is, for example, a natural number of 30 or less, preferably 15 to 25). The fourth servo pattern area 210d is formed over m4 tracks (m4 is, for example, a natural number of 30 or less, preferably 15 to 25). The method of selecting ml to m4 is the same as the method of selecting n1 to n4.

The clock marks 111 formed in the servo pattern areas 210 a to d are referred to as clock marks 211 a to d, respectively. Similarly, the first and second wobbled marks 1 12 and 2 13 formed in the servo pattern areas 210 a to d are respectively Marks 2 1 2 a to 2 d and second double mark 2 13 a to d. Here, as shown in FIG. 6, the central angles formed by the clock marks 222 a to d and the first wobbled marks 222 a to d are α 1 a to d, respectively. In addition, the center angles formed by the clock marks 222 a to d and the second pebble marks 222 a to d are α 2 a to d, respectively. At this time, they satisfy the following relationship.

That is, the first servo pattern area 210a and the second servo pattern area 210b are defined by the clock mark 2 21 and the second

The central angles formed by 23 are substantially equal (α 2 a = α 2 b). The second servo pattern area 210 b and the third servo pattern area 210 c have substantially the same central angle formed by the clock mark 2 21 and the first wobble mark 222. (Alb = alc). Also, the third servo pattern area 210c and the fourth servo pattern area 210d are defined by the clock mark 222 and the fourth servo pattern area 210d.

The center angles formed by the two wobble marks 2 2 and 3 are substantially equal (α 2 c and 2 d). The first servo pattern area 210a and the fourth servo pattern area 210d are defined by the clock mark 2 21 and the first double mark 2 2

The central angles formed by 2 are approximately equal (α 1 a α 1 d).

In the optical recording medium 200, the central angle formed by the clock mark and the pebble mark is different for each servo pattern area. Therefore, as described in the third embodiment, the movement direction of the optical spot is detected with respect to the relative movement in the radial direction between the optical recording medium 200 and the optical spot irradiated on the optical recording medium 200. can do.

In the optical recording medium 200, the central angle formed by the click mark 2 21 and the first double mark 2 22 or the clock mark 2 2 between two radially adjacent servo pattern areas 1 and 2nd wobble mark 2 2

One of the central angles formed by 3 is substantially equal. That is, radially adjacent Between the two servo pattern areas, only one of the arrangement of the wobbled marks 222 and the arrangement of the wobbled marks 223 changes. According to this configuration, even when the optical spot passes near the boundary between two radially adjacent servo pattern areas, information from one of the two servo pattern areas can be obtained. Therefore, according to the optical recording medium 200, the movement direction of the optical spot can be detected particularly accurately.

(Embodiment 3)

In a third embodiment, an example of the direction detection device of the present invention will be described. FIG. 7 schematically shows an example of the configuration of a direction detecting device 300 of Embodiment 3 using the optical recording medium of the present invention. In the following description, the case where the optical recording medium 100 described in the first embodiment is used will be described, but another optical recording medium of the present invention may be used.

Referring to FIG. 7, the direction detection device 300 includes a detection circuit 301, a clock mark detection circuit 302, a comparator 303, a timing signal generator 304, and a signal. And a generation circuit 305. The signal generation circuit 300 includes a double mark position detection circuit 303, a first latch circuit (identification circuit) 300a, a second latch circuit 300, and a direction signal generation circuit 300. 8 is provided.

In order to read the data signal recorded in the data area 120, the optical recording medium 100 is irradiated with an optical spot along the track center line 102. However, if the center of the disk of the optical recording medium 100 and the center of the data area are eccentric, the light spot and the optical recording medium 100 rotate when the optical recording medium 100 rotates. Accordingly, it relatively moves in the radial direction. The light spot and the optical recording medium 100 also move relative to each other in the radial direction due to an impact or the like. Also, at the time of access, the light spot and the optical recording medium 100 relatively move in the strange direction. The direction detection device 300 of the present invention This is an apparatus for detecting the moving direction of such a light spot in the radial direction with respect to the recording medium 100.

The detection circuit 301 includes a semiconductor laser or the like that generates a light spot irradiated on the optical recording medium 100 in order to read information, and reflected light detection means that detects reflected light from the optical recording medium 100. And The detection circuit 301 outputs a reproduction signal DRF corresponding to the detected reflected light. That is, the detection circuit 301 functions as clock mark detection means and double mark detection means. The output reproduction signal DRF is input to the clock mark detection circuit 302 and the comparator 303.

The clock mark detection circuit 302 detects the clock mark 111 of the optical recording medium 100 and outputs a clock mark detection signal CD. Here, since the servo area 110 and the data area 120 are alternately arranged in the circumferential direction on the optical recording medium 100, the data is always read before the servo area 110. Evening area is 120. Further, since no mark is arranged in the data area 120, the clock mark 111 can be easily detected by detecting the first mark among the consecutive marks as the clock mark 111. The output clock mark detection signal CD is input to the timing signal generator 304.

The timing signal generator 304 predicts the timing at which the reproduction signal DRF of the first and second wobble marks 112 and 113 will be generated based on the input clock mark detection signal CD. Outputs the imaging signals P1, P2, P3 and P4. Further, the timing signal generator 304 outputs an output signal PL1 obtained by delaying the input clock mark detection signal CD by a predetermined time. As described above, the timing signal generator 304 functions as timing signal generating means. The output signal PL1 is output from the first latch circuit 307a and the second latch circuit Input to 30 b.

As shown in the configuration diagram of the support area 110 in FIG. 2, the place where the reproduction signal DRF of the first double mark 111 is generated is at an interval L1a (L1a) from the clock mark 111. d) and the timing shifted from the clock mark 111 by the interval Lib (L1c). Therefore, two types of timing signals, P1 and P2, are required as timing signals for detecting the first wobble mark 112.

The timing signal P1 is used to detect a first double mark 111a or 112d that is shifted from the clock mark 111 by an interval L1a. Further, the timing signal P2 is used to detect the first double mark 112b or 112c which is shifted from the clock mark 111 by an interval L1b.

Also, as shown in FIG. 2, the reproduction signal DRF of the second double mark 113 is generated at a timing shifted from the clock mark 111 by an interval L2a (= L2b), These are two points with the timing shifted from the mark 1 1 1 by the interval L 2 c (= L 2 d). For this reason, two types of timing signals, P3 and P4, are required as timing signals for detecting the second pebble mark 113.

The timing signal P 3 is used to detect a second cobble mark 1 13 a or 1 13 b that is offset from the clock mark 11 1 by an interval L 2 a, and the timing signal P 4 is used to detect the clock mark 11 It is used to detect a second pebble mark 1 13 c or 1 13 d that is shifted from L 1 c by L 2 c.

As described above, the timing signals P1, P2, P3 and P4 are output by the timing signal generator 304.

The comparator 303 binarizes the reproduction signal DRF and outputs the output signal DF. Output. That is, the reproduction signal DRF is equal to a predetermined value (here, the average value of the reproduction signal DRF in the data area 120 and the average value of the reproduction signal DRF at the position of the first wobbled mark 112 or the second wobbled mark 113) If the playback signal DRF is smaller than a predetermined value, "H" (here, "L" indicates a low voltage level) is output. "H" stands for high voltage level). Marks such as the clock mark 111, the first wobbled mark 112, and the second wobbled mark 113 are formed by the concave / convex shape of the reflection film in the optical recording medium 100. Therefore, when the optical spot passes in the vicinity of these marks, the amount of reflected light is lower than that in the area without these marks, and the reproduction signal DRF is smaller. In particular, when the light spot is located at the center of the pebble mark, the amount of reflected light is the minimum value.

Therefore, the output signal DF of the comparator 303 becomes an "H" signal in the vicinity of the clock mark 111, the first wobbled mark 112, and the second wobbled mark 113.

The output signal DF of the comparator 303 is input to the double mark position detection circuit 303. The timing signals P 1, P 2, P 3 and P 4 output from the timing signal generator 304 are also input to the double mark position detection circuit 303.

The double mark position detection circuit 303 is a circuit that functions as double mark position detection means. Using the timing signals P 1, P 2, P 3 and P 4, the output signal DF of the comparator 303 is sampled by the wobbled mark position detection circuit 306, and the wobbled mark position signals J 1, J 2 , J 3 and J 4 are output. The double mark position signals J1, J2, J3 and J4 are input to a first latch circuit 307a. Here, the double mark position detection circuit 300 is composed of four latch circuits 3 06a, 306b, 306c and 306d are provided.

The latch circuit 306a latches the output signal DF of the comparator 303 with the timing signal P1 of the timing signal generator 304, and outputs the latch result as an output signal J1. Specifically, when the playback signal DRF of the first double mark 112 is generated at the timing of the timing signal P1, an "H" signal is output as the output signal J1 of the latch circuit 310a. When the reproduction signal DRF of the first double mark 1 12 does not occur at the timing of the timing signal P 1, an “L” signal is output as the output signal J 1 of the latch circuit 106 a. Is done. That is, if the first wobbled mark 112 is present at a position separated from the clock mark 111 by the interval L1a (if the first wobbled mark 211a or 221d is present), The output signal J 1 is an “H” signal. On the other hand, if the first double mark 112 does not exist at that position, the output signal J 1 becomes an “L” signal.

Similarly, the latch circuit 306b also outputs the output signal J 2 with the signal of “H” when the first double mark 1 1 2 exists at a position L 1 b away from the click mark 1 1 1. Become. On the other hand, when the first wobble mark 112 does not exist at that position, the output signal J 2 becomes an “L” signal.

Similarly, when the latch circuit 303c has the second double mark 113 at a position separated by the interval L2a from the click mark 111, the output signal J3 is a signal of "H". Becomes On the other hand, if the second wobble mark 113 does not exist at that position, the output signal J 3 becomes an “L” signal.

Similarly, the latch circuit 303d is output when the second double mark 113 is located at a position L2c away from the click mark 111. The force signal J 4 is a “H” signal. On the other hand, if the second wobble mark 113 does not exist at that position, the output signal J4 becomes an "L" signal.

The operation of the double mark position detection circuit 303 when the detection circuit 301 passes through the first servo pattern area 110a will be described with reference to FIG.

When the optical spot passes through the first servo pattern area 110a, the amount of reflected light decreases when passing through each mark, and as shown in Fig. 8, the reproduction signal DRF is shifted downward at the position corresponding to each mark. It has a convex waveform.

The reproduction signal DRF is input to the comparator 303, and the output signal DF is output from the comparator 303. The timing signal generator 304 outputs timing signals PI, P2, P3, and P4.

In the first servo pattern area 110a, the latch circuit 303a latches the output signal DF at the timing of the timing signal P1, so that the "H" signal is output at the timing of the timing signal P1. Become. In the latch circuit 306b, the output signal DF is latched at the timing of the timing signal P2, so that the signal becomes “L”. In the latch circuit 306c, the output signal DF is latched at the timing of the evening timing signal P3, so that the signal becomes "H" at the timing of the timing signal P3. Since the output signal DF is latched at the timing of the timing signal P4 in the latch circuit 360d, the signal becomes "L".

Therefore, the output signals J 1, J 2, J 3 and J 4 when passing through the first servo pattern area 110 a are “H”, “L”, “H” and “L”, respectively. Become. From the output signals J1, J2, J3 and J4, it can be detected that the signal has passed the first servo pattern area 110a.

Similarly, the detection circuit 310 passes through the second servo pattern area 110b. In this case, the double mark position detection circuit 306 operates as follows. In the second servo pattern area 110b, the latch circuit 306a latches the output signal DF at the timing of the timing signal P1, so that the signal becomes "L". In the latch circuit 306b, the output signal DF is latched at the timing of the timing signal P2, so that the signal becomes “H” at the timing of the timing signal P2. In the latch circuit 306c, the output signal DF is latched at the evening of the evening timing signal P3, so that the signal becomes "H" at the timing of the timing signal P3. In the latch circuit 306d, the output signal DF is latched at the timing of the timing signal P4, so that the signal becomes “L”.

Therefore, as shown in FIG. 9, the output signals J 1, J 2, J 3 and J 4 when the light spot passes through the second servo pattern area 110 b are “L” and “H”, respectively. "," H "and" L ". From the output signals J 1, J 2, J 3 and J 4, it can be detected that the second servo pattern area 110 b has passed.

As shown in FIG. 10, when the light spot passes through the third servo pattern area 110c, the output signals J1, J2, J3 and J4 are each "L". , "H", "shi", "H". From the output signals J 1, J 2, J 3 and J 4, it can be detected that the signal has passed the third servo pattern area 110 c.

As shown in FIG. 11, the output signals J 1, J 2, J 3 and J 4 when the optical spot passes through the fourth servo pattern area 110 d are respectively “ H "," L "," S ", and" H ". From the output signals J 1, J 2, J 3 and J 4, it can be detected that the signal passes through the fourth servo pattern area 110 d.

The first latch circuit (identification circuit) 307 a has a Output signals J 1, J 2, J 3 and J 4 from the output circuit 303 are input. The output signal PL 1 from the timing signal generator 304 is input to each of the first latch circuit 307 a and the second latch circuit 307.

The first latch circuit 307 a holds the state of the output signals J 1, J 2, J 3, and J 4 of the wobbled mark position detection circuit 303 at the evening of the output signal PL 1 and outputs the timing signal J Outputs the identification signal JS1 corresponding to 1, J2, J3, and J4. Specifically, when the timing signals J1, J2, J3, and J4 are "H", ": L", "H", and "L", respectively (the first servo pattern area 110) outputs a value of "1" as the identification signal JS1. When the timing signals J1, J2, J3, and J4 are "L", "H", "H", and "L" respectively (the second servo pattern area 110b) ), A value of "2" is output as the identification signal JS1. In addition, when the timing signals J 1, J 2, J 3, and 4, respectively, are “HI”, “H”, “L” and “H” (corresponding to the third servo pattern area 110 c) Then, a value of "3" is output as the identification signal JS1. When the timing signals J 1, J 2, J 3, and J 4 are “H”, “L”, “L”, and “H”, respectively (corresponding to the fourth servo pattern area 110 d) ) Outputs a value of "4" as the identification signal JS1. As described above, the first latch circuit (identification circuit) 307a functions as identification means for identifying the type of the service area using the detection signal of the double mark position detection means 303 and outputting an identification signal. I do.

The second latch circuit 307b holds the value of the identification signal JS1 at the timing of the output signal PL1 of the timing signal generator 304 and outputs it as the identification signal JS2. That is, the identification signal JS2 of the second latch circuit 307b is one timing before the identification signal JS1 of the first latch circuit 307a. Value.

The output signals J 1 and J of the double mark position detection circuit 310 when the optical spot irradiated on the optical recording medium 100 moves in the outer peripheral direction in each of the servo pattern areas of the optical recording medium 100. FIG. 12 shows changes in 2, J 3 and J 4 and changes in the identification signals JS 1 and JS 2. Also, the output signal J l of the double mark position detection circuit 310 when the light spot irradiated on the optical recording medium 100 moves in the inner circumferential direction in each servo pattern area of the optical recording medium 100. , J2, J3, and J4, and the changes in the identification signals JS1 and JS2 are shown in FIG.

As shown in FIGS. 12 and 13, the identification signal JS 2 of the second latch circuit 3 07 b is used to indicate the value of the identification signal JS 1 of the first latch circuit 3 07 a one timing before. The direction signal generation circuit 308 determines whether the optical spot is moving in the inner circumferential direction or the outer circumferential direction by comparing the values of the identification signals JS 1 and JS 2. it can. Then, the direction signal generation circuit 308 outputs the result of the determination as the direction signal DR. That is, the direction signal generation circuit 308 functions as a direction signal generation unit that detects the relative movement direction of the optical spot and the optical recording medium in the radial direction from the change in the identification signal, and outputs a direction signal.

When an optical recording medium having a different number of servo pattern areas from that of the optical recording medium 100 is used, the number of timing signals and the number of latch circuits may be changed according to the configuration of the servo pattern area.

In the third embodiment, the case where the light spot and the optical recording medium relatively move at a constant linear velocity has been described. However, the present invention can be applied to a case where information is recorded / reproduced while rotating the optical recording medium at a constant angular velocity. In this case, the relative movement speed of the light spot becomes higher toward the outer periphery of the disk. For this reason, detection information from optical recording media or mechanical detection The position of the optical spot may be detected by the detector, and the time for generating the timing signal may be changed according to the radial position. Further, by using these methods, the present invention can be applied to an optical recording medium in which the rotational angular velocity or the linear velocity of the optical recording medium is changed every fixed area.

Further, the direction detection device may further include a circuit for counting the number of tracks moved in the radial direction of the optical spot. This circuit is composed of a memory for storing the number of tracks nl to n4 in the servo pattern areas 110a to d, and a circuit for counting the servo pattern area to which the optical spot has moved. This circuit can speed up the operation when the optical spot accesses a predetermined position on the optical recording medium. Further, when the light spot moves due to an impact or the like, it becomes easy to detect the position of the light spot.

As described above, an example of the embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and can be applied to various embodiments based on the technical idea of the present invention.

For example, in the above embodiment, the optical recording medium mainly provided with four types of servo pattern areas has been described. However, even in the case of an optical recording medium having three or five or more types of servo pattern areas, the movement direction of the relative movement between the optical spot and the optical recording medium can be similarly detected. In this case, the direction detection device may change the number of timing signals output from the timing signal generator and the number of latch circuits according to the optical recording medium to be used.

Further, the direction detection device of the present invention may perform the direction detection process by directly converting the reproduced signal from analog to digital. In this case, it is needless to say that the same effect can be obtained.

Further, the optical recording medium of the present invention provides an optical recording medium between a servo area and a data area. Another area such as an address area where a dress mark is formed may be provided.

Industrial applicability

The optical recording medium of the present invention can be applied to an optical recording medium that reproduces information using light, such as a CD, CD-R, CD-RW, DVD, and MD. According to the optical recording medium of the present invention, it is possible to easily and accurately detect the relative movement direction of the light spot with respect to the optical recording medium. Further, according to the optical recording medium of the present invention, the number of radially moving tracks of the optical spot with respect to the optical recording medium can be easily counted.

Further, according to the direction detection device of the present invention, the relative movement direction of the light spot with respect to the optical recording medium of the present invention can be detected easily and accurately. This direction detecting device can be used for a recording / reproducing device such as an optical disk drive.

Claims

The scope of the claims

1. A disk-shaped optical recording medium in which a plurality of servo areas and data areas are alternately arranged along a track center line,

The service area includes a clock mark, a first wobble mark, and a second wobble mark,

A plurality of servo areas constitute a plurality of servo pattern areas which are repeatedly arranged in the radial direction in order,

An optical recording medium in which the plurality of servo pattern areas are different from each other in at least one arrangement selected from an arrangement of the first wobble mark with respect to the clock mark and an arrangement of the second wobble mark with respect to the clock mark.

2. The plurality of servo pattern regions are different from each other in at least one interval selected from the interval between the clock mark and the first wobbled mark and the interval between the clock mark and the second wobbled mark. The optical recording medium according to claim 1.

3. The plurality of servo pattern regions are formed between two servo pattern regions radially adjacent to each other, the distance between the click mark and the first wobble mark, or the distance between the click mark and the second wobble mark. 3. The optical recording medium according to claim 2, wherein one of the distances is substantially equal.

4. The plurality of servo pattern areas include a first servo pattern area, a second servo pattern area, a third servo pattern area, and a fourth servo pattern area,

The first servo pattern area and the second servo pattern area have substantially equal intervals between the clock mark and the second wobble mark. The second servo pattern area and the third servo pattern area have substantially equal intervals between the clock mark and the first wobble mark, and the third servo pattern area and the fourth servo pattern area The distance between the clock mark and the second wobble mark is substantially equal, and the distance between the clock mark and the first wobble mark is substantially the same between the first servo pattern region and the fourth servo pattern region. The optical recording medium according to claim 3.

5. The optical recording medium according to claim 4, wherein a plurality of the servo areas are radially arranged, and a circumferential length of the servo area is constant.

6. The plurality of servo pattern regions are at least selected from a central angle formed by the clock mark and the first pebble mark, and a central angle formed by the clock mark and the second pebble mark. 2. The optical recording medium according to claim 1, wherein both the central angles are different.

7. The plurality of servo pattern regions may be formed such that a central angle formed by the click mark and the first double mark between two radially adjacent servo pattern regions, or the click mark and the second mark 7. The optical recording medium according to claim 6, wherein one of central angles formed by the wobbled marks is substantially equal.

8. The plurality of servo pattern areas include a first servo pattern area, a second servo pattern area, a third servo pattern area, and a fourth servo pattern area,

The first servo pattern area and the second servo pattern area have substantially the same central angle between the click mark and the second wobble mark,

The second support pattern region and the third support pattern region , The center angle between the click mark and the first wobble mark is approximately equal,

The third support pattern area and the fourth support pattern area have substantially the same central angle between the clock mark and the second wobble mark,

8. The optical recording medium according to claim 7, wherein the first servo pattern region and the fourth servo pattern region have substantially the same central angle between a click mark and a first double mark.

9. A direction detection device for detecting a radial relative movement direction of an optical recording medium and an optical spot irradiated on the optical recording medium for reading information recorded on the optical recording medium, ,

The optical recording medium according to any one of claims 1 to 8, wherein the optical recording medium includes a service area in which a clock pit, a first double pit, and a second double pit are formed to form a plurality of support pattern areas. And

Detecting means for detecting the clock mark;

Timing signal generating means for generating an evening signal in response to the clock mark detected by the detecting means;

Using the timing signal, a double mark position detecting means for detecting the position of the first double mark and the position of the second double mark and outputting a detection signal;

Identification means for identifying the type of the service area using the detection signal and outputting an identification signal;

A direction detection device comprising: a direction signal generation unit that detects a relative movement direction of the optical spot and the optical recording medium in a radial direction from a change in the identification signal and outputs a direction signal.