JP2004126038A - Optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a spindle for driving an optical disk where information is recorded by holography surely insertable into the optical disk. <P>SOLUTION: The optical disk 1 is equipped with a laminated structure 3 formed by laminating a transparent substrate 5, a recording layer 7 for hologram recording, a transparent substrate 9, and a transparent substrate 11 with pits 13 (preformatted area). The shaft insertion member 19 of the optical disk 1 is fixed to the laminated structure 3 while inserted into a through hole 17 provided at the center part of the laminated structure 3. The shaft insertion member 19 has an insertion hole 21 into which the spindle is to be inserted. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical information recording medium on which information is recorded by holography.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a method of recording information at high density on an optical disc in the form of image information by holography. Recording of image information in this method is realized by superimposing the information light carrying the image information and the reference light on the recording layer of the optical disc and writing the interference fringe pattern generated by the interference between the information light and the reference light on the recording layer. Is done. When the reproduction illumination light is applied to the recording layer on which the interference fringe pattern is written, the irradiated light is diffracted by the interference fringe pattern, thereby reproducing image information.
[0003]
A hole is provided in the center of the optical disc. The rotation of the optical disk during recording and reproduction is realized by inserting the spindle (shaft) of the optical disk drive into the hole, fixing the optical disk to the spindle, and rotating the spindle. Therefore, if the hole is inclined while the hole is inserted into the spindle, or if the spindle is not smoothly inserted into the hole, the operation of automatic insertion and automatic removal of the optical disk in the drive device can be facilitated. It becomes impossible.
[0004]
[Problems to be solved by the invention]
The optical disc on which information is recorded by holography has a recording layer sandwiched between a pair of transparent substrates, and another transparent substrate on which a preformat area (emboss pit) in which a sector address, a track address, and the like are recorded is formed. It has a structure of being superposed on one of a pair of transparent substrates. The preformat area may be formed on one of the transparent substrates.
[0005]
In general, an optical disc is manufactured by previously providing a hole for inserting a spindle (shaft) in each of the above-mentioned substrates, and superimposing these substrates. If the positioning accuracy of each substrate is poor at the time of superposition, the center of the hole of each substrate is displaced and the spindle cannot be inserted into the hole of the optical disk. To prevent this, if the hole is formed to be large, large vibration or eccentricity occurs in the optical disk when the optical disk is driven, and accurate recording and reproduction cannot be performed.
[0006]
The present invention has been made in view of such a problem, and an object of the present invention is to provide an optical information recording medium in which a shaft for driving an optical information recording medium can be reliably inserted into the medium.
[0007]
[Means for Solving the Problems]
An optical information recording medium according to the present invention is an optical information recording medium on which information is recorded by holography, and includes a recording layer for hologram recording and a pair of transparent substrates holding the recording layer therebetween, and is preformatted. A laminated structure having a region and a through-hole penetrating the recording layer and a pair of transparent substrates at a location where a shaft for driving the optical information recording medium is inserted, and a laminated structure inserted into the through-hole. A shaft insertion member fixed and having an insertion hole into which the shaft is inserted.
[0008]
According to the optical information recording medium of the present invention, the shaft for driving the optical information recording medium is not inserted into the laminated structure itself, but the insertion hole of the shaft insertion member provided separately from the laminated structure. To be plugged in. Since the dimensions of the insertion hole are not affected by the positioning when the laminated structure is manufactured, the shaft can be securely inserted into the insertion hole.
[0009]
In the optical information recording medium according to the present invention, the shaft insertion member may have a flange fixed to the laminated structure. According to this, even if the shaft insertion member is smaller than the through hole, the shaft insertion member can be fixed to the laminated structure so that the shaft insertion member can be reliably inserted into the through hole of the laminated structure. it can.
[0010]
In the optical information recording medium according to the present invention, the shaft insertion member may have a property of being attracted to the magnet. According to this, the shaft insertion member can be attracted to the shaft for driving the optical information recording medium by magnetic force, and the stability of mounting the optical information recording medium on the shaft can be improved.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of an optical disc (an example of an optical information recording medium) 1 according to this embodiment. Digital information is recorded on the optical disc 1 by holography. As shown in FIG. 1, the optical disc 1 includes a disc-shaped laminated structure 3. The laminated structure 3 has a structure in which a transparent substrate 5, a recording layer 7 for hologram recording, a transparent substrate 9, and a transparent substrate 11 are laminated. The material of the transparent substrate 5 and the transparent substrate 9 is, for example, glass, quartz, diamond, resin (such as polycarbonate). The transparent substrates 5 and 9 may be in a plate shape, a film shape or a transparent coat film shape. The thickness of the transparent substrates 5 and 9 is, for example, 5 to 1200 μm.
[0012]
The recording layer 7 is held between a pair of transparent substrates 5 and 9. When the recording layer 7 is irradiated with laser light serving as information light or reference light for a predetermined period of time, the material of the recording layer 7 has optical characteristics (refractive index, absorptance, transmittance, This is a hologram recording material that changes its fluorescence and reflectivity. Specifically, for example, it is a photopolymer (Photopolymers) HRF-600 (product name) manufactured by Dupont. The thickness of the recording layer 7 is, for example, 4 to 1000 μm.
[0013]
On one surface of the transparent substrate 11, pits 13 indicating servo information, address information of sectors and tracks, and the like are formed. The pits 13 are formed in advance when the optical disc is manufactured. The area where the pits 13 are formed is a preformat area. An aluminum layer (not shown) is formed on the transparent substrate 11 so as to cover the pits 13. This aluminum layer functions as a layer that reflects laser light. The surface of the transparent substrate 11 where the pits 13 are formed is adhered to the transparent substrate 9 by a transparent resin 15.
[0014]
A through hole 17 that penetrates through the laminated structure 3 is formed at the center of the laminated structure 3, that is, at a position where a spindle for driving the optical disc 1 is inserted. The shaft insertion member 19, which is a component of the optical disc 1, is fixed to the laminated structure 3 while being inserted into the through hole 17. The shaft insertion member 19 has a cylindrical shape, and a flange 23 is formed at one end. The diameter D of the flange 23 is larger than the diameter of the through hole 17. By attaching the shaft insertion member 19 to the transparent substrate 11 at the flange 23, the shaft insertion member 19 is fixed to the laminated structure 3.
[0015]
The shaft insertion member 19 has a cylindrical shape as described above, and a space surrounded by the cylinder becomes the insertion hole 21. A spindle (an example of a shaft for driving the optical information recording medium) for driving the optical disc 1 is inserted into the insertion hole 21. As described above, in the optical disc 1 according to the present embodiment, the spindle is reliably inserted into the insertion hole 21 by providing the shaft insertion member 19 having the insertion hole 21 into which the spindle is inserted separately from the laminated structure 3. Like that. The material of the shaft insertion member 19 is a ferromagnetic material such as iron or nickel. In addition, plastic and the like can also be used.
[0016]
Next, a method for recording information on the optical disc 1 using volume holography, which is one mode of holography, will be briefly described with reference to FIG. FIG. 2 is an enlarged view of a part of the laminated structure 3 of the optical disc 1. In FIG. 2, the same elements as those indicated by the reference numerals in FIG. 1 are denoted by the same reference numerals. According to the above recording, the interference fringe pattern can be three-dimensionally written on the recording layer 7 of the optical disk 1, and the recording density can be further increased.
[0017]
An aluminum layer 25 not shown in FIG. 1 is laminated on the pit 13 forming surface of the transparent substrate 11 by, for example, a method such as vapor deposition. The aluminum layer 15 functions as a layer that reflects laser light.
[0018]
The information light L1 and the reference light L2 are laser lights that have passed through the lens 27 of the optical head. The recording layer 7 is simultaneously irradiated with the information light L1 and the reference light L2 from the transparent substrate 5 side to record the interference fringe pattern P on the recording layer 7. The spot on the recording layer 7 where the interference fringe pattern is recorded is called a spot S. FIG. 3 is a plan view of a part of the spot group. By slightly rotating the optical disc 1, a new spot S (in this case, a spot S2) that partially overlaps the spot S (for example, the spot S1) that has been formed earlier in a plane is formed on the recording layer 7. . By repeating this, the interference fringe pattern is multiplex-recorded on the recording layer 7.
[0019]
Next, an example of a method for manufacturing the optical disc 1 will be described in detail with reference to FIGS. FIG. 4 is a schematic sectional view of the optical disc 1 shown in FIG. In FIG. 4, half of the shaft insertion member 19 shows a cross section of the shaft insertion member 19, and the other half shows the appearance.
[0020]
The through holes 17 a and 17 b of the transparent substrates 5 and 9 are passed through the shaft insertion member 19, and are disposed to face each other with a gap corresponding to the thickness of the recording layer 7. The shaft insertion member 19 has a function of aligning the transparent substrates 5 and 9. Since the through holes 17a and 17b become the through holes 17, their diameters are the same as the diameter of the through holes 17. The recording layer 7 is formed by filling the gap with a liquid or gel hologram recording material. By arranging a spacer (not shown) around the gap, the hologram recording material is prevented from leaking out of the gap.
[0021]
A transparent substrate 11 having pits 13 and through holes 17c is prepared. The diameter of the through hole 17c is the same as the diameter of the through hole 17 because the through hole 17c becomes the through hole 17. A liquid transparent resin 15 functioning as an adhesive is applied to the surface of the transparent substrate 11 on which the pits 13 are formed. Then, by inserting the shaft insertion member 19 into the through hole 17c of the transparent substrate 11 and the through holes 17a and 17b of the laminate of the transparent substrate 5, the recording layer 7 and the transparent substrate 9, the laminate and the transparent The laminated structure 3 is formed by aligning the substrate 11 and bonding the transparent substrate 11 to the transparent substrate 9 with the transparent resin 15. Then, the optical disk 1 is completed by bonding the flange 23 to the transparent substrate 11 and fixing the shaft insertion member 19 to the laminated structure 3.
[0022]
Note that the outer diameter d of the shaft insertion member 19 causes a gap between the outer peripheral surface 29 of the shaft insertion member 19 and the side surface of the through hole 17 when the shaft insertion member 19 is inserted into the through hole 17. The dimensions. Although the outer peripheral surface and the side surface are expressed as being in contact with each other in FIG. 1, the gap is actually formed. Due to the above gap, the shaft insertion member 19 can be reliably inserted into the through hole 17 even if the positioning accuracy of the transparent substrates 5, 9, 11 is somewhat poor. In this embodiment, the shaft insertion member 19 is attached to the laminated structure 3 by bonding the flange 23 to the transparent substrate 11. Therefore, the shaft insertion member 19 can be fixed to the laminated structure 3 even if the above gap is formed. Note that a cylindrical shaft insertion member having no flange 23 may be inserted into the through hole 17 to fill the gap with resin or the like.
[0023]
In the case of a type in which a spindle for driving the optical disk 1 is inserted into the through-hole 17 like a conventional optical disk, the diameter of the through-hole 17 is made larger than the diameter of the spindle, so that the transparent substrates 5, 9, 11 The spindle can be inserted into the through-hole 17 even if the positioning accuracy of is slightly poor. However, when the optical disk is driven, large vibration or eccentricity occurs in the optical disk, and accurate recording and reproduction cannot be performed.
[0024]
On the other hand, according to the optical disc 1 of the present embodiment, the spindle is not inserted into the laminated structure 3 itself, but is inserted into the insertion hole 21 of the shaft insertion member 19 provided separately from the laminated structure 3. I try to insert it. Since the diameter of the insertion hole 21 is not affected by the alignment of the transparent substrates 5, 9, and 11 when the laminated structure 3 is manufactured, the spindle can be reliably inserted into the insertion hole 21.
[0025]
In this embodiment, the shaft insertion member 19 is used as a member for positioning the transparent substrates 5, 9, and 11, but this positioning member and the shaft insertion member 19 are separate members. It may be. Alternatively, a mark may be provided in advance on each of the transparent substrates 5, 9, and 11, and alignment may be performed using the mark as a mark.
[0026]
Next, a device (hereinafter, referred to as a drive device) 31 for recording / reproducing information on / from the optical information recording medium according to the present embodiment will be described. FIG. 5 is a block diagram showing the configuration of the drive device 31. The drive device 31 has at least one of a recording function and a reproducing function.
[0027]
The drive device 31 includes a motor 37 in which a spindle 35 (an example of a shaft for driving an optical information recording medium) is fixed to a rotating shaft 33. The optical disc 1 is fixed to the spindle 35 by inserting the spindle 35 into the insertion hole of the shaft insertion member 19 of the optical disc 1 according to the present embodiment, and the optical disc 1 is rotated by the rotation of the spindle 35.
[0028]
FIG. 6 is a sectional view showing a state where the spindle 35 is inserted into the insertion hole 21 of the shaft insertion member 19. The spindle 35 has a cylindrical portion 39 inserted into the insertion hole 21, and a flange 41 is formed on a side portion on the motor 37 side. The flange 41 functions as a turntable on which the optical disc is placed. A magnet 43 is mounted on the upper surface of the flange 41. Since the material of the shaft insertion member 19 is a ferromagnetic material such as iron or nickel, the shaft insertion member 19 of the optical disc 1 can be attracted to the magnet 43 of the spindle 35. Therefore, the rotation stability of the optical disc 1 during recording and reproduction can be improved, and the characteristics of the drive device 31 such as recording and reproduction can be improved. The flange 41 may be a ferromagnetic material and the shaft insertion member 19 may be a magnet, or the shaft insertion member 19 may be a magnet and a magnet may be attached to the flange 41.
[0029]
Other configurations of the drive device 31 will be briefly described. The spindle servo circuit 45 controls the motor 37 so as to keep the rotation speed of the spindle 35 at an appropriate value. The optical head 47 includes a semiconductor laser and various optical devices (lens, mirror, and the like). During recording, the optical head 47 irradiates the optical disc 1 with information light and reference light. At the time of reproduction, the optical head 47 irradiates the optical disk 1 with light similar to the reference light and detects image information reproduced thereby. These lights are shown as light L in FIG. The moving mechanism 49 moves the optical head 47 in the radial direction of the optical disc 1 with the spindle 35 inserted into the shaft insertion member 19 of the optical disc 1.
[0030]
The control circuit 51 performs various controls such as focus servo control, tracking servo control, tracking servo control, and slide servo control. The focus servo control is control for adjusting the focus of the optical head 47 on the optical disc 1. The tracking servo control is a control for performing tracking adjustment of the optical head 47 with respect to the optical disc 1. The tracking servo control is a control for causing the optical head 47 to follow the irradiation positions of the information light and the reference light so as not to be shifted for a predetermined time. These controls are performed by moving the lens of the optical head 47. The slide servo control is control for moving the optical head 47 in the radial direction of the optical disc 1 by the moving mechanism 49.
[0031]
There are several modifications in the present embodiment, which will be described with reference to FIGS. In these drawings, the same elements as those indicated by the reference numerals in FIGS. 1 and 6 are denoted by the same reference numerals. FIG. 7 is a schematic sectional view of an optical disc 61 according to a first modification. 1 in that the flange 23 of the shaft insertion member 19 is located on the transparent substrate 5 side. FIG. 8 is a schematic sectional view showing a state where the optical disk 61 of FIG. 7 is fixed to the spindle 35.
[0032]
FIG. 9 is a schematic sectional view of an optical disc 63 according to a second modification. FIG. 10 is an enlarged view of the shaft insertion member 65 of the optical disk 63. A half of the shaft insertion member 65 shows a cross section of the shaft insertion member 65, and the other half shows an appearance. The difference from the optical disc 61 in FIG. 7 is that the diameter of the opening 67 is smaller than the diameter of the insertion hole 21 at the end of the shaft insertion member 65 opposite to the flange 23. FIG. 11 is a schematic sectional view showing a state where the optical disk 63 of FIG. A magnet 69 is mounted on an end of the spindle 35 opposite to the flange 41. A portion defining the opening 67 of the shaft insertion member 65 is attracted to the magnet 69. Note that the flange 23 of the shaft insertion member 65 may be located on the transparent substrate 11 side, as in the optical disc 71 of the third modification shown in FIG.
[0033]
FIG. 13 is a schematic sectional view of an optical disc 73 according to a fourth modification. 1 is different from the optical disc 1 of FIG. 1 in that a pit 75 is formed on the transparent substrate 9 and an aluminum layer (not shown) serving as a reflection layer is formed on the transparent substrate 9 so as to cover the pit 75. That is, the protective layer 77 made of resin is laminated.
[0034]
FIG. 14 is a schematic sectional view of an optical disk 79 according to a fifth modification. 13 is that the flange 23 of the shaft insertion member 19 is located on the transparent substrate 5 side. FIG. 15 is a schematic cross-sectional view of an optical disk 81 according to a sixth modification, which differs from the optical disk 73 of FIG. 13 in that a shaft insertion member 65 shown in FIG. 12 is used as a shaft insertion member. . FIG. 16 is a schematic cross-sectional view of an optical disc 83 according to a seventh modification, which differs from the optical disc 81 shown in FIG. 15 in that the flange 23 of the shaft insertion member 65 is located on the transparent substrate 5 side.
[0035]
The optical disk (optical information recording medium) according to the present embodiment may have a disk shape, for example, a triangular shape, a square shape, a hexagonal shape, or the like, and a card-like container approximately the size of a business card. The present embodiment can be applied to an optical information recording medium having a disk-shaped recording area.
[0036]
【The invention's effect】
As described above, according to the optical information recording medium of the present invention, apart from the laminated structure of the optical information recording medium, the optical information recording medium is provided with the shaft insertion member provided with the insertion hole. An axis for driving the medium can be reliably inserted into the optical information recording medium.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an optical disc according to an embodiment.
FIG. 2 is an enlarged view of a part of a laminated structure of the optical disk of FIG.
FIG. 3 is a plan view of a part of a spot group formed on a recording layer of the optical disc according to the embodiment.
FIG. 4 is a schematic sectional view of the optical disk of FIG. 1 exploded.
FIG. 5 is a block diagram showing a configuration of an apparatus for recording and reproducing information on an optical information recording medium according to the embodiment.
6 is a sectional view showing a state where the spindle of FIG. 5 is inserted into an insertion hole of a shaft insertion member of the optical disc of FIG. 1;
FIG. 7 is a schematic sectional view of an optical disc according to a first modification of the embodiment.
8 is a schematic sectional view showing a state where the optical disk of FIG. 7 is fixed to a spindle.
FIG. 9 is a schematic sectional view of an optical disc according to a second modified example of the embodiment.
FIG. 10 is an enlarged view of a shaft insertion member of the optical disc of FIG. 9;
FIG. 11 is a schematic cross-sectional view showing a state where the optical disk of FIG. 9 is fixed to a spindle.
FIG. 12 is a schematic sectional view of an optical disc according to a third modification of the embodiment.
FIG. 13 is a schematic sectional view of an optical disc according to a fourth modification of the embodiment.
FIG. 14 is a schematic cross-sectional view of an optical disc according to a fifth modification of the present embodiment.
FIG. 15 is a schematic sectional view of an optical disc according to a sixth modification of the embodiment.
FIG. 16 is a schematic sectional view of an optical disc according to a seventh modification of the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical disk, 3 ... Laminated structure, 5 ... Transparent substrate, 7 ... Recording layer, 9 ... Transparent substrate, 11 ... Transparent substrate, 13 ... Pit (Preformat Area), 15: transparent resin, 17, 17a, 17b, 17c: through hole, 19: shaft insertion member, 21: insertion hole, 23: flange, 25 ... Aluminum layer, 27 lens, 29 outer peripheral surface, 31 drive device for optical information recording medium, 33 rotating shaft, 35 spindle, 37 motor, 39. Cylinder, 41 Flange, 43 Magnet, 45 Spindle servo circuit, 47 Optical head, 49 Moving mechanism, 51 Control circuit, 61 Optical disk , 63 ... optical disk, 65 ... shaft insertion member, 67 ... opening, 6 ... magnet, 71 ... optical disk, 73 ... optical disk, 75 ... Pit, 77 ... protective layer, 79 ... optical disk, 81 ... optical disk, 83 ... optical disk

Claims (3)

An optical information recording medium on which information is recorded by holography,
Including a recording layer for hologram recording and a pair of transparent substrates holding the recording layer in between, having a pre-format area and at the location where the axis for driving the optical information recording medium is inserted, the recording layer and the A laminated structure having a through-hole penetrating a pair of transparent substrates,
A shaft insertion member fixed to the laminated structure while being inserted into the through hole, and having an insertion hole into which the shaft is inserted,
An optical information recording medium comprising: The optical information recording medium according to claim 1, wherein the shaft insertion member has a flange fixed to the laminated structure. 3. The optical information recording medium according to claim 1, wherein the shaft insertion member has a property of being attracted to a magnet.

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