KR20040104284A - High density optical disc having a difference thickness between information area and clamping area, and optical disc device therof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high density optical disc having a different thickness of an information area and a thickness of a clamping area, and an optical disc device accordingly, wherein a high density optical disc such as a Blu-ray disc (BD) is turned upside down on a turntable provided in the optical disc device. When the lens is inserted into the optical pickup, it is allocated between the clamping area and the information area of the high density optical disc so that the high density optical disc and the objective lens do not collide with each other even if the objective lens OL of the optical pickup is vertically moved up to the maximum movable range OD_Max. In the transition region, a step with a predetermined angle is formed, and the thickness of the information area is made smaller than the thickness of the clamping area, thereby causing damage and a deadly servo due to the collision between the objective lens OL of the optical pickup and the high density optical disk. It is possible to effectively prevent the occurrence of errors, and also to reconstruct high density optical discs. Non-reducing as well as being able to keep the clamping power, it would be very useful inventions are able to be further securely inserted into a high density optical disc in the slot-in (Slot-In) the type of the optical disc drive.

Description

High density optical disc having a difference thickness between the information area and the clamping area, and thus an optical disc device

The present invention, in order to prevent the high-density optical disk and the objective lens of the optical pickup collide when the high-density optical disk, such as a Blu-ray Disc (BD) is inverted in the optical disk device The present invention relates to a high density optical disc having a different thickness of an information region and a thickness of a clamping region, and an optical disc apparatus accordingly.

A typical CD has a disc thickness of 1.2 mm and a disc diameter of 120 mm, a center hole of 15 mm diameter, a turntable and a clamper provided in an optical disc apparatus, as shown in FIG. It is made of a structure having a clamping area of 44 mm diameter to be clamped by).

On the other hand, the data recording layer recorded on the CD in a pit pattern is about 1.2 mm in a direction opposite to an object lens (OL) of an optical pickup included in the optical disk device. The optical pickup for the CD has a value of NA = 0.45 where the numerical aperture (NA) is relatively small.

As shown in FIG. 2, a general DVD includes a turntable and a clamper provided in a 1.2 mm disk thickness, a 120 mm disk diameter, and a 15 mm diameter center hole and an optical disk device. The data recording layer, which is manufactured in a structure having a clamping area of 44 mm diameter to be clamped by the optical disc, has a data recording layer recorded in a pit pattern on the DVD, the objective lens of the optical pickup included in the optical disk device. The optical pickup for the DVD has a value of NA = 0.6 with a relatively large numerical aperture NA formed in a position spaced about 0.6 mm apart in the direction opposite to OL.

On the other hand, high-density optical disks, such as Blu-ray disks (BD), which have been recently discussed for standardization, have a disk thickness of 1.2 mm, a disk diameter of 120 mm, and a central hole of 15 mm diameter, as shown in FIG. Manufactured with a structure having a clamping area of 33 mm diameter clamped by a turntable and a clamper provided in the optical disk device, and a transition area of 42 mm diameter allocated between the clamping area and the information area. do.

The data recording layer recorded on the Blu-ray Disc BD in a pit pattern is spaced about 0.1 mm apart in a direction opposite to the objective lens OL of the optical pickup included in the optical disk device. Formed in a closed position.

The optical pickup for the Blu-ray Disc has, for example, a numerical value of NA = 0.85 where the numerical aperture (NA) is relatively large, and for reproducing or recording pit-shaped data recorded at high density, Compared with (CD) and DVD (DVD), a short wavelength laser beam is used.

Therefore, while the objective lens OL of the optical pickup for the Blu-ray disc is brought closer to the recording layer of the Blu-ray disc, the laser beam of short wavelength is emitted and the numerical aperture NA of the objective lens is increased. This makes it possible to form a laser beam of a larger amount of light into a small beam spot in a pit shape recorded at a high density, and to shorten the light transmitting layer through which the short wavelength laser beam is transmitted to the shortest distance. In addition, it is possible to minimize the change in the properties of the laser beam and the occurrence of aberration.

On the other hand, as shown in FIG. 4, when the Blu-ray disc 10 is normally inserted and seated on the turntable 11 provided in the optical disc apparatus, a normal servo operation, for example, a spindle motor ( 12) and the objective lens OL of the optical pickup 14 is rotated at a high speed by servo operation by the motor driver 13 and the servo controller 15. By a focusing operation of moving up and down with the above, a reading or writing operation of data that is high-density recorded in a pit shape after being focused is normally performed.

However, as shown in FIG. 5, when the Blu-ray disc 10 is inserted in an error state in an inverted state on the turntable 11 provided in the optical disc apparatus, as described above, the Blu-ray disc 10 may be used. The disk 10 is rotated at high speed by the servo operation by the spindle motor 12, the motor driver 13, and the servo controller 15. At this time, the recording layer of the erroneously inserted Blu-ray disc is normally inserted. Compared to the recording layer of the seated Blu-ray Disc, the optical film 14 is located at least 1.1 mm further from the objective lens OL of the optical pickup 14.

Therefore, the normal data reading or writing operation is not performed by the normal focusing operation in which the objective lens OL of the optical pickup 14 is moved up and down, thereby controlling the focusing operation. In the controller 15, the objective lens OL of the optical pickup continues to move vertically in the direction of the recording layer of the Blu-ray disc 10 until the maximum movable range OD_Max. The Blu-ray Disc 10 collides with each other, causing the Blu-ray Disc or the optical lens of the optical pickup to be broken, or a fatal error in the servo operation.

The present invention has been made to solve the above problems, and when the high density optical disc such as a Blu-ray disc (BD) is misinserted in an inverted state in the optical disc apparatus, the objective lens (OL) of the optical pickup is operated at maximum. High density optical discs having different thicknesses of the information area and the clamping area so that the objective lens OL and the high density optical disc of the optical pickup do not collide with each other even if they are vertically moved to the recording layer of the high density optical disc up to the range OD_Max. And to provide an optical disk device accordingly, the purpose is to.

1 shows a disc structure for a typical CD (CD),

2 shows a disc structure for a general DVD (DVD),

3 shows a disc structure for a typical Blu-ray disc (BD),

4 and 5 illustrate a state in which a Blu-ray disc is normally inserted and a state in which a Blu-ray disc is normally inserted into a general optical disc device.

6 illustrates a cross-sectional view of a high density optical disc according to the present invention,

7 illustrates a state in which an objective lens is not collided due to a slope step according to the present invention.

8 illustrates a state in which the high density optical disc according to the present invention is normally inserted into the optical disc apparatus.

9 illustrates a state in which a high density optical disc according to the present invention is misinserted into an optical disc apparatus.

10 to 15 show embodiments of the high-density optical disk and the experimental results according to the present invention,

* Explanation of symbols for main parts of the drawings

10,20 Blu-ray Disc 11: Turntable

12: spindle motor 13: motor driver

14 optical pickup 15 servo controller

In order to achieve the above object, a high-density optical disc having a thickness different from that of an information region and a clamping region according to the present invention is a high-density optical disc in which a high-density pit-shaped data recording layer is formed to be shifted from one side of the center of the disc thickness. The thickness of the information area of the high-density optical disk is smaller than the thickness of the clamping area.

In addition, in the high density optical disc in which the thickness of the information area and the clamping area are different from each other, the high density optical disc has a high-density pit-shaped data recording layer formed to be offset from one side of the center of the disc thickness. In the transition region allocated between the clamping region and the information region, a step having an inclination of a predetermined angle is formed so that the thickness of the information region is smaller than the thickness of the clamping region,

In addition, an optical disc apparatus according to the present invention comprises: an optical pickup for reading data recorded on a high density optical disc; Servo means for performing a servo operation on the high density optical disc and an optical pickup; And signal processing means for processing a reproduction signal of data read by the optical pickup, wherein the optical pickup reads data recorded in a program area having a thickness smaller than that of a clamping area of the high density optical disk. It is characterized by shipping.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a high-density optical disc and an optical disc apparatus according to the present invention, in which the thickness of the information area and the thickness of the clamping area are different from each other, will be described in detail with reference to the accompanying drawings.

First, FIG. 6 shows a cross-sectional view of a high density optical disc according to the present invention. The high density optical disc, for example, the Blu-ray disc 20, has a disc thickness of 1.2 mm as described above with reference to FIG. A disc diameter of 120 mm and a clamping area of 33 mm diameter clamped by a 15 mm diameter center hole and a turntable and clamper provided in the optical disc device, and between the clamping area and the information area. It is made of a structure having a transition area of 42 mm diameter assigned.

In addition, the data recording layer recorded in the Pit Pattern is formed at a position spaced about 0.1 mm apart in a direction opposite to the objective lens OL of the optical pickup included in the optical disk device. The thickness of the clamping region and the thickness of the information region are formed differently, for example, as shown in FIG. 6, in the disc cross-sectional direction opposite to the recording layer, 0.1 to 0.6 mm in a portion of the transition region. A step having a predetermined thickness is formed so that the thickness of the information area is smaller by 0.1 to 0.6 mm in thickness than the thickness of the transition area.

When the Blu-ray disc 20 is inverted and seated on a turntable provided in the optical disc apparatus, the step is moved vertically to the maximum movable range OD_Max for focusing. In order to ensure that the Blu-ray disc 20 and the objective lens do not collide with each other, to ensure a separation distance between the Blu-ray disc and the objective lens of the optical pickup, the Blu-ray disc 20 and the objective lens are formed with a step of 0.1 to 0.6 mm in thickness. As shown in FIG. 5, the slope type step is formed from the end of the clamping region to the part before the start of the information region.

On the other hand, as shown in Fig. 7, the Blu-ray disc is flipped over and inserted into the device while the slope type step is formed from the end of the clamping area of 33 mm diameter to the start of the information area of 42 mm diameter. In Example 1, the optical pickup and the high-density optical disk collide due to the maximum horizontal moving range of the objective lens OL.

Therefore, in the preferred embodiment of the present invention, the slope type step is formed in a portion of the transition region, for example, from the end of the clamping region of 33 mm diameter, 2.0 mm before the beginning of the information region of 42 mm diameter. By forming the slope type step only up to the portion, as shown in FIG. 7, even when the Blu-ray disc is flipped into the apparatus and inserted incorrectly (Example 2), the optical pickup can be operated by the maximum horizontal movement range of the objective lens OL. It is possible to prevent the collision between the high-density optical disk and the optical disk.

In addition, a slope of up to 3.5 mm (= (40-33) / 2) can be formed in a disc width direction based on the center hole of the optical disc, and the clamping area can be extended even after a diameter of 33 mm. Considering this, it can have a minimum slope length of 1.8 mm (= (40-36.4) / 2) in the width direction. The minimum slope length of 1.0 mm (= (40-38) / 2) should be set in consideration of the optical disc manufacturing deviation. In the embodiment of the present invention, a slope length of 1.0 mm or more and 3.5 mm or less is preferably set in the width direction.

On the other hand, when the Blu-ray disc 20 is normally inserted on the turntable 11 provided in the optical disk apparatus as shown in FIG. 8, the clamping region is normally seated on the turntable 11 and clamped. At this time, since there is no change in the thickness of the clamping region, it is possible to maintain a stable clamping power (Clamping Power) as it is, as well as the thickness of the information region is thin, so that the centrifugal force is relatively generated at high speed rotation, more stable The clamping power can be secured.

Further, in the state where the spindle motor 12, the motor driver 13 and the servo controller 15 are rotated at high speed by the normal servo operation, the objective lens OL of the optical pickup 14 has a predetermined movable range. (OD) A focusing operation that is moved up and down with the OD is performed to normally read or write data that is high density and then recorded in a pit shape after being focused.

On the other hand, as shown in FIG. 9, when the Blu-ray disc 20 is incorrectly inserted in an inverted state on the turntable 11 provided in the optical disc apparatus, the Blu-ray disc 20 As described above, the clamping region is mounted between the end face of the clamping area seated on the turntable 11 and the end face of the clamping area seated on the turntable 11 due to the slope type step formed in the transition area. A separation distance of 0.1 mm to 0.6 mm occurs.

Therefore, in the state of being rotated at high speed by the normal servo operation by the spindle motor 12, the motor driver 13 and the servo controller 15, the objective lens OL of the optical pickup 14 is the maximum for focusing. Even if it is vertically moved to the movable range OD_Max, it is possible to prevent the Blu-ray disc 20 and the objective lens OL from colliding with each other.

In addition, since the recording layers of the data recorded in the pit shape are spaced far from each other and thus the normal focusing operation cannot be performed, the Blu-ray disc 20 and the object lens OL collide with each other. It can be prevented efficiently.

Further, by widening the maximum movable range OD_Max for the objective lens OL to focus, the number of focusing error detections caused by the limitation of the maximum movable range can be greatly reduced, and the information of the Blu-ray disc By making the thickness of the area smaller than 1.2 mm, it is possible to reduce the material cost required to manufacture the disc, and when the user pushes the Blu-ray disc into a slot-in type optical disc drive by hand, Even when a collision occurs due to the step, the impact is minimized due to the slope shape, so that smooth insertion is possible.

Meanwhile, the reason why it is preferable to form the slope step in the transition region of 0.1 to 0.6 mm will be described in detail as follows. As shown in FIG. 10, the maximum thickness of the clamping region of the Blu-ray disc BD is 1.3. Except for a 0.1 mm thick cover layer, the thickness of the injection substrate may be 1.2 mm.

And, when the information area and the rim area are made thinner than the thickness of the clamping area by placing a step on the opposite side of the cover layer, the transferability of the grooves or pits formed on the recording surface at the time of injection is different from the thickness of the ejection substrate of the general DVD. Since it is the same, no problem occurs.

Therefore, even in the case of a Blu-ray disc, an injection substrate having a minimum thickness of 0.6 mm can be manufactured without any problem in injection. As shown in FIG. 10, a step of the Blu-ray disc is formed, and the thickness of the clamping region is increased. When the thickness is 1.2 mm, the substrate thicknesses of the information region and the rim region can be manufactured up to 0.6 mm without problems of injection characteristics and transfer characteristics, and the step can be sufficiently up to 0.6 mm.

At this time, when a cover layer having a thickness of 0.1 mm is manufactured on the recording surface side, a Blu-ray disc having a thickness of 1.3 mm for the clamping area and 0.7 mm for the information area and the rim area can be manufactured. Is at least 1.15mm, if the step is 0.6mm, the thickness of the information area and the rim area is 0.55mm, and after subtracting the thickness of 0.1mm of the cover layer, the thickness of the injection substrate is 0.45mm, in this case 0.45mm thickness It is also possible to fabricate the injection substrate of the.

On the other hand, the reason for setting the minimum value of the step is 0.1mm, as shown in Fig. 11, the working range (WD) of the Blu-ray Disc objective lens having a numerical aperture (NA) of 0.85 is about 0.5 If the size is larger than mm, collision prevention can be performed even at a minimum step of about 0.1 mm. That is, since the distance that can be moved up and down for the focusing operation of the objective lens can be up to + 0.5mm to at least -0.5mm from the focusing position basis, it is possible to secure a mechanical margin to prevent collision. In the case where the movable range WD is small, the effect of collision avoidance becomes larger as the step of the disc becomes larger, and when the movable range is larger, the collision can be avoided even when the step is smaller.

For example, as shown in Figure 12, using a polycarbonate material, a 1.1mm / 0.8mm thickness of the injection substrate is fabricated, a cover layer of 100um is produced, the clamping area thickness 1.2mm, information When the area and rim area thickness are 0.9 mm, the radial angular deviation (α) is the normal test conditions defined in the Blu-ray disc, that is, the temperature 23 ± 2 ° C., relative It satisfies the maximum angular deviation (α = 0.70 degrees) required at relative humidity of 45% to 55% and atmospheric pressure of 86kPa to 106kPa.

In addition, as shown in FIG. 13, when polycarbonate is used as the injection substrate, the Blu-ray disc conditions in the Sudden Change Test (ie, the Sudden Change Test) up to 0.9 mm in thickness, that is, 95% relative humidity and 25 ° C relative humidity, are measured. Changed from 45% RH to 25 ° C, and 45% RH, from 25 ° C to 30.0% RH and 70 ° C with Absolute Humidity at a constant level. When the angular deviation in the conditions (α = 0.80 degrees) is satisfied, but thinner than 0.9 mm, it is difficult to meet the above conditions, so that the minimum thickness of the disc when the plastic material of the injection substrate is used is polycarbonate. Is preferably set to 0.9mm. However, when using a plastic material having a higher rigidity than polycarbonate as the injection substrate material, the thickness can be made thinner than 0.9mm. do.

As shown in FIG. 14, when there is no tray, such as a slot-in-type drive, and a disc needs to be directly loaded or unloaded into a drive, there is a vertical step. Although the disk may be stepped by the mechanism and the loading may fail, as shown in FIG. 15, when the disc is made to be inclined at about 30 degrees (= 0.6 mm / 1.0 mm) or less, It is possible to prevent the step in advance.

As described above, the above-described preferred embodiment of the present invention is disclosed for the purpose of illustration, and the step formed in the transition region may have various other shapes in addition to the slope type, and those skilled in the art will disclose the following appended claims. Within the spirit and scope of the present invention, various other embodiments may be improved, changed, replaced or added.

The high-density optical disc having different heights at the upper and lower surfaces of the clamping area according to the present invention, which is configured as described above, has a high-density optical disc such as a Blu-ray disc (HD-DVD), which is misinserted with the turntable provided in the optical disc apparatus. In the case of Error Insertion, even if the objective lens OL of the optical pickup is vertically moved to the maximum movable range OD_Max, the upper and lower surfaces of the clamping region of the high density optical disk are prevented from colliding with each other. By forming a different height relative to the center of the disk thickness, it is possible to further secure a predetermined separation distance between the high-density optical disk and the objective lens of the optical pickup, the objective lens (OL) and the high-density optical disk of the optical pickup It is a very useful invention that can prevent the damage caused by the collision between and the occurrence of fatal servo error at the source.

Claims (10)

In a high-density optical disc in which a high-density pit-shaped data recording layer is formed by shifting from the center of the disc thickness to one side, And a thickness of the information area and a thickness of the clamping area are different from each other, wherein a thickness of the information area of the high density optical disc is smaller than that of the clamping area. The method of claim 1, And a step is formed in the transition region allocated between the clamping region and the information region of the high density optical disk, wherein the thickness of the information region and the thickness of the clamping region are different from each other. The method of claim 2, And wherein the step is formed at a predetermined angle from the end of the clamping region to the part before the start of the information region, wherein the thickness of the information region and the thickness of the clamping region are different from each other. The method of claim 3, wherein The step is formed from an end of the clamping region with an inclination of a predetermined angle, the thickness of the information region and the clamping region of the information region, characterized in that formed at least 2.0 mm before the portion where the information region begins. High density optical discs with different thicknesses. The method of claim 2, And the height of the step is 0.1 mm to 0.6 mm, wherein the thickness of the information area and the thickness of the clamping area are different from each other. In a high-density optical disc in which a high-density pit-shaped data recording layer is formed by shifting from the center of the disc thickness to one side, A thickness having an inclination of a predetermined angle is formed in the transition region allocated between the clamping region and the information region of the high density optical disk, so that the thickness of the information region is smaller than the thickness of the clamping region. And a high density optical disc having different thicknesses of the clamping region. The method of claim 6, The high density optical disc is a Blu-ray disc, wherein the step is formed in a portion of the transition region of the Blu-ray disc with an inclination of a predetermined angle, characterized in that formed in the step height of 0.1 mm to 0.6 mm A high density optical disc formed with a thickness different from that of the clamping region. The method of claim 2, And said step is formed with respect to the disk surface located far from the optical disk recording layer. Optical pickup for reading data recorded on the high density optical disk; Servo means for performing a servo operation on the high density optical disc and an optical pickup; And A signal processing means for processing a reproduction signal of data read by the optical pickup, And the optical pickup reads out data recorded in a program area having a thickness smaller than that of the clamping area of the high density optical disc. The method of claim 9, And the servo means extends and controls the maximum moving range of the objective lens provided in the optical pickup to a position higher than a planar position of the clamping region of the high density optical disk mounted in the apparatus.