JP2007052893A - Optical information recording medium and method and apparatus for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing an optical information recording medium which can suppress unevenness in the thickness of a radiation curable resin rising by surface tension near the outer circumferential edge part of a substrate and suppress generation of burr to the outside of the substrate, when the radiation curable resin is applied on the substrate. <P>SOLUTION: The method for manufacturing the optical information recording medium including the substrate having at least one layer of signal recording layer and a resin layer transmitting light includes a step of applying the radiation curable resin on the substrate and a step of reducing the rotation speed after accelerating the substrate up to a first rotation speed and performing irradiation with radiation during the reduction of the rotation speed to cure at least a part of the radiation curable resin, thereby forming the resin layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical information recording medium manufacturing method and manufacturing apparatus, and an optical information recording medium, and in particular, a high density in which the thickness of an intermediate layer, a light transmission layer, a protective layer, and the like made of a radiation curable resin is reduced. The present invention relates to a method for manufacturing an optical information recording medium.

  In recent years, research on various optical information recording has been advanced in the field of information recording. This optical information recording can be densified, can be recorded / reproduced in a non-contact manner, and is being realized in a wide range of applications as a method that can be realized at low cost. Current optical discs include a structure in which an information layer is provided on a transparent resin substrate with a thickness of 1.2 mm and protected by an overcoat (compact disc (CD)), or one or both of a 0.6 mm transparent resin substrate A structure (digital versatile disk (DVD)) in which an information layer is provided on the two and these two sheets are bonded together is used.

  In recent years, methods for increasing the numerical aperture (NA) of an objective lens and methods for shortening the wavelength of a laser to be used have been studied as methods for increasing the recording density of an optical disk. At this time, if the thickness of the recording / reproducing side base material (the substrate on which the laser beam is incident) is thinner, the influence of the aberration received by the laser spot can be reduced, and the allowable value of the tilt angle (tilt) of the disk can be increased. Therefore, it has been proposed that the thickness of the recording / reproducing side base material is about 0.1 mm, the NA is about 0.85, and the laser wavelength is about 400 nm (Blu-ray disc) (for example, (See Patent Document 1). However, at this time, it is preferable that the thickness variation of the recording / reproducing side base material is suppressed to within 5% from the influence of the recording / reproducing light on the focus and spherical aberration. In such an optical disc having a recording / reproducing side base material of 0.1 mm, the thickness is preferably 1.2 mm as in the case of CD and DVD from the viewpoint of compatibility.

  Such a Blu-ray disc recording / reproducing side substrate is as thin as about 0.1 mm and cannot be produced by injection molding that has been used in the production of conventional optical discs. In general, in the case of a substrate having a diameter of about 12 cm, if the thickness is less than 0.3 mm, it is very difficult to form by injection molding. Further, the recording / reproducing side base material is required to have a very high thickness accuracy. Therefore, a method in which a sheet produced using a method such as casting is punched into a disk shape and bonded to a substrate has become the mainstream. However, in this method, the material cost of the sheet is very high, and the optical disk becomes expensive.

  Therefore, it has been proposed to form a recording / reproducing side base material by applying a radiation curable resin using a method such as spin coating and curing it (see, for example, Patent Document 2).

  However, since the recording / reproducing side substrate is required to have a very high thickness accuracy, a high technique is also required for spin coating. In particular, when a liquid UV resin is applied, if the rotation of the substrate is stopped after application, the UV resin rises due to surface tension at the outer peripheral portion of the circular substrate. In order to solve this, it has been proposed to cure the UV resin by performing UV irradiation while accelerating the number of rotations of the substrate (see, for example, Patent Document 3).

  Furthermore, in order to ensure the beauty of the vicinity of the outer peripheral edge of the optical disk, it has also been proposed to cure the UV resin while shielding the outer peripheral edge of the substrate (see, for example, Patent Documents 4 and 5).

Japanese Patent Laid-Open No. 08-235638 Japanese Patent Laid-Open No. 10-289489 International Patent Publication No. WO02 / 101737 Pamphlet Japanese Patent No. 2924255 JP-A-10-199056

  However, in each of the above methods, it is impossible to achieve both high thickness accuracy required for the recording / reproducing side base material and aesthetics in the vicinity of the outer peripheral edge of the optical disc, and to manufacture an optical disc that is stable at the mass production level. It was difficult.

  For example, after applying resin to the substrate, when UV irradiation is performed while rotating the substrate at a constant rotation speed, the thickness becomes extremely thin near the outer peripheral edge of the substrate, or the resin protrudes from the outer peripheral edge of the substrate There was a problem of being cured as it was.

  In addition, when UV irradiation is performed while accelerating the number of rotations of the substrate, uniform thickness accuracy can be realized, but if UV irradiation is performed before the excess resin on the outer peripheral edge of the substrate is completely shaken off, the film is shaken off. In some cases, burring occurred on the outside of the substrate. If the acceleration is too large, not only the excess resin but also the resin slightly inside the outer peripheral edge of the substrate (that is, the vicinity of the outer peripheral edge) is shaken off, and the resin coating thickness near the outer peripheral edge of the substrate is thin. There was a problem that it might become.

  Accordingly, an object of the present invention is to manufacture an optical information recording medium having a light transmission layer, an intermediate layer, and a protective layer made of a radiation curable resin, and when the radiation curable resin is applied to the substrate, An object of the present invention is to provide an optical information recording medium manufacturing method and manufacturing apparatus capable of suppressing the thickness unevenness of the radiation curable resin raised by the surface tension in the vicinity of the end and suppressing the occurrence of burrs on the outside of the substrate.

In order to solve the above problems, an optical information recording medium manufacturing method according to the present invention is a method for manufacturing an optical information recording medium including a substrate having at least one signal recording layer and a light-transmitting resin layer. ,
Applying a radiation curable resin on the substrate;
After accelerating the number of revolutions of the substrate and reaching the first number of revolutions, the number of revolutions is decelerated and radiation is applied during the deceleration of the number of revolutions to cure at least a portion of the radiation curable resin. And a step of forming a resin layer. According to this method for producing an optical information recording medium, an optical information recording medium having a light transmission layer and an intermediate layer made of a radiation curable resin that is very uniform in thickness up to the vicinity of the outer peripheral edge and can be produced.

  Further, in the step of forming the resin layer, after reaching a second rotational speed lower than the first rotational speed, the resin layer is irradiated with radiation to cure at least a part of the radiation curable resin. May be formed.

  Furthermore, in the step of forming the resin layer, the substrate is irradiated with radiation while rotating the substrate at the second rotation speed for a predetermined time, and at least a part of the radiation curable resin is cured to form a resin layer. Also good.

  Still further, in the step of forming the resin layer, a light shielding mask having a circular hole having an inner diameter equal to or smaller than the outer diameter of the substrate, the hole of the light shielding mask being concentric with the substrate. The resin layer may be formed by irradiating the substrate with radiation through the light shielding mask and curing at least a part of the radiation curable resin.

  Further, after the step of forming the resin layer, a step of accelerating the number of revolutions of the substrate to a predetermined number of revolutions higher than the first number of revolutions, and shaking off the radiation curable resin at the outer peripheral end of the substrate. May further be included.

  Further, after the step of shaking off the radiation curable resin at the outer peripheral end of the substrate, the method further includes the step of irradiating the outer peripheral end of the substrate with radiation to cure the radiation curable resin at the outer peripheral end of the substrate. But you can.

  In addition, you may perform the application | coating process of the said radiation curable resin by a spin coat method.

  Further, in the step of applying the radiation curable resin, a substrate having a center hole may be used to close the center hole and apply the radiation curable resin to the substrate.

  Further, the resin layer may be a light transmission layer provided on the signal recording layer. Alternatively, the resin layer may be a protective layer. The resin layer may be an intermediate layer provided between a plurality of signal recording layers.

Furthermore, after the step of forming the resin layer,
A step of applying a stamper having grooves or concave and convex pits to the radiation curable resin obtained by curing at least a part of the substrate, and further irradiating with radiation to cure the radiation curable resin to form an intermediate layer. Further, it may be included.

An apparatus for manufacturing an optical information recording medium according to the present invention includes a turntable for rotatably holding a substrate having a surface coated with a radiation curable resin,
A motor for rotating the rotary table;
A radiation lamp for irradiating the radiation curable resin on the substrate with radiation to cure at least a part of the radiation curable resin;
A controller that controls the number of rotations of the motor and the irradiation timing of the radiation lamp.

  And a radiation mask having a circular hole having an inner diameter equal to or smaller than the outer diameter of the substrate, wherein the radiation lamp is not in contact with the substrate between the substrate and the radiation lamp. The light shielding mask may be further provided so that the hole is concentric with the substrate when viewed from the side. In this case, the substrate is irradiated with radiation from the radiation lamp through the light shielding mask.

  Further, the control unit accelerates the rotational speed of the motor, and after the first rotational speed is reached, decelerates the radiation curable composition on the substrate from the radiation lamp during the deceleration of the rotational speed. The resin may be irradiated with radiation.

  Still further, the control unit accelerates the rotational speed of the motor, reaches the first rotational speed, decelerates, reaches the second rotational speed lower than the first rotational speed, and then Radiation may be emitted from a radiation lamp.

The optical information recording medium according to the present invention is an optical information recording medium manufactured by the manufacturing method,
The thickness of the resin layer in the vicinity of the outer peripheral edge of the substrate is 10 μm or more thinner than the average thickness of the entire resin layer on the substrate.

  According to the method for producing an optical information recording medium according to the present invention, even when a light transmission layer is produced from a liquid material such as a radiation curable resin, the thickness accuracy is high and there is no burr on the outside of the substrate, and the appearance is excellent An optical information recording medium can be produced.

  An optical information recording medium manufacturing apparatus and manufacturing method according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals. In the drawings, if the central axis is bilaterally symmetric, only one side from the symmetrical axis is shown, and the other may be omitted.

(Embodiment 1)
An optical information recording medium manufacturing apparatus and manufacturing method according to Embodiment 1 of the present invention will be described. FIG. 1 is a block diagram showing a configuration of an optical information recording medium manufacturing apparatus according to Embodiment 1 of the present invention. The optical information recording medium manufacturing apparatus includes a rotary table 20 that rotatably holds a substrate 11 coated with a radiation curable resin 18, a motor 30 that rotates the rotary table 20, and radiation curable on the substrate 11. A radiation lamp 40 that irradiates the resin 18 with radiation 15 and cures at least a part of the radiation curable resin 18, and a control unit 50 that controls the rotation speed of the motor 30 and the irradiation timing of the radiation lamp 40 are provided. Further, the manufacturing apparatus may further include a light shielding mask 60 disposed between the substrate 11 and the radiation lamp 30 in a non-contact manner with respect to the substrate 11. As shown in FIG. 2A, the light shielding mask 60 has a circular hole having an inner diameter equal to or smaller than the outer diameter of the substrate 11, and the hole is viewed from the radiation lamp 40 side. And are arranged so as to be concentric. In this case, the radiation 15 is irradiated from the radiation lamp 40 to the radiation curable resin 18 on the substrate 11 through the light shielding mask 60.

Each member constituting the optical information recording medium manufacturing apparatus will be described.
First, as the radiation lamp 40, any radiation lamp that can irradiate radiation for curing the radiation curable resin 18 may be used. For example, a circular lamp can be used as the radiation lamp 40. The circular radiation lamp 40 can irradiate the entire radiation curable resin on the substrate 11 with radiation. The shape of the radiation lamp 40 is not limited to a circle, and may be another shape. Further, in order to cure the radiation curable resin 18 during the rotation of the substrate 11, it is preferable that the radiation curable resin 18 can be cured in as short a time as possible. For example, in the case where a UV lamp is used as the radiation lamp 40, the radiation curable resin 18 can be cured to such an extent that it is not stretched by a rotation of about 1200 rpm by irradiating one pulse of ultraviolet light. For example, as the radiation lamp 40, a UV irradiator of a type capable of performing pulse irradiation (RC-747 manufactured by Xenon) can be used. According to this UV irradiator, ultraviolet irradiation of one pulse and several tens of ms can be performed. The term “radiation” as used herein is a concept that includes all electromagnetic waves that can cure the radiation curable resin 18, such as infrared rays, visible rays, ultraviolet rays, and X-rays.

  Next, the light shielding mask 60 will be described with reference to FIG. 2A is a plan view showing the positional relationship between the light shielding mask 60 and the substrate 11, and FIG. 2B is a schematic sectional view of FIG. The light shielding mask 60 has a circular hole having an inner diameter equal to or smaller than the outer diameter of the substrate 11, and has a donut-shaped light shielding portion on the outer side thereof. The light shielding mask 60 is disposed so that the hole is concentric with the substrate 11 when viewed from the radiation lamp 40 side, and shields only the outer peripheral edge of the substrate 11. For example, the inner diameter of the donut-shaped light shielding mask 60 may be 118 mm in diameter. Since the radiation curable resin 18 on the substrate 11 is irradiated with radiation through the light shielding mask 60, the outer peripheral edge of the substrate 11 is not irradiated with radiation. Therefore, the radiation curable resin 18 that is about to be shaken off by rotation from the outer peripheral end portion of the substrate 11 is not irradiated with radiation and is not cured, so that it can be shaken off as it is. Further, if the light shielding mask 60 is used, it is possible to reliably prevent the radiation curable resin 18 shaken off from the substrate 11 from being exposed to the radiation 18, so that there is an advantage that extra radiation curable resin can be recycled.

  The position where the light shielding mask 60 is provided is preferably close to the substrate 11. On the other hand, if the radiation curable resin 18 adheres to the light shielding mask 60, the thickness unevenness of the resin layer increases. Therefore, the light shielding mask 60 is preferably provided at a predetermined distance without being brought into contact with the radiation curable resin 18 on the substrate 11. For example, the shortest distance between the light shielding mask 60 and the substrate 11 is set to about 500 μm.

  The light shielding mask 60 can be used as long as it can shield radiation. Specifically, a mask made of a metal material can be used as the light shielding mask 60. More specifically, for example, it may be made from a metal whose main material is Al. Alternatively, SUS or the like may be used. When the radiation 15 is reflected by the light shielding mask 60, the surface of the light shielding mask 60 may be coated or colored.

  Further, the light shielding mask 60 may be a light shielding mask 60 whose lower surface has a cross section parallel to the substrate 11 as shown in FIG. 3A, and from the substrate 11 toward the outer peripheral side as shown in FIG. 3B. The light-shielding mask 60a may have a cross section that is cut obliquely so as to move away. The light shielding mask 60 preferably has a shape in which the outer peripheral end portion of the substrate 11 is sufficiently shielded from light and the radiation curable resin 18 to be shaken off does not adhere to the light shielding mask 60.

  The light shielding mask 60 is not necessarily an essential member in the optical recording medium manufacturing apparatus. The light shielding mask 60 is provided so that the radiation curable resin 18 at the outer peripheral edge of the substrate 11 is not irradiated with the radiation 15. Therefore, for example, by using a linear light source or the like as the radiation lamp 40, the radiation 15 is irradiated only to the radiation curable resin 18 on the substrate 11, and is not irradiated to the radiation curable resin 18 at the outer peripheral edge of the substrate 11. By doing so, the light shielding mask 60 may not be used.

  Moreover, the control part 50 is realizable with a computer as a physical structure, for example, The operation | movement is realizable with a computer program. The controller 50 controls the rotation speed of the motor 30 and the radiation irradiation timing of the radiation lamp 40. For example, in the control unit 50, the rotational speed of the motor 30 is accelerated to the first rotational speed and then decelerated, and the radiation 15 is transferred from the radiation lamp 40 to the radiation curable resin 18 on the substrate 11 during the deceleration of the rotational speed. Can be irradiated. Further, the controller 50 may accelerate the motor 30 to the first rotational speed, decelerate it, reach the second rotational speed lower than the first rotational speed, and then irradiate the radiation 15. Good.

Next, a method for manufacturing the optical information recording medium according to Embodiment 1 will be described using the flowchart of FIG. 4 and the time chart of FIG. FIG. 4 is a flowchart of the method for manufacturing the optical information recording medium according to the first embodiment. FIG. 5 is a time chart showing the relationship between the number of rotations of the substrate 11 and time in the method for manufacturing an optical information recording medium according to Embodiment 1 of the present invention.
(1) A radiation curable resin 18 is applied on the substrate 11 (S01). For example, the radiation curable resin 18 dropped while rotating the substrate 11 may be stretched and applied onto the substrate 11 (spin coating).
(2) Next, the number of rotations of the substrate 11 is accelerated to reach a predetermined number of rotations (for example, FIG. 5: number of rotations 1200 rpm) and then decelerated to reduce the number of rotations of the substrate 11 (for example, At a rotation speed of 900 rpm, the radiation curable resin 18 on the substrate 11 is irradiated with radiation 15 from the radiation lamp 40 through the light shielding mask 60 to cure the radiation curable resin 18 (S02). For example, in the time chart of FIG. 5, 4 seconds after the acceleration, the rotation speed reaches 1200 rpm, and then the vehicle is decelerated, and after 1 second from the deceleration, the radiation 15 is irradiated at the rotation speed of 900 rpm. This is also called spin cure.
(3) The number of rotations of the substrate 11 is accelerated, and the excess radiation curable resin 18 at the outer peripheral end is shaken off (S03). In the example of FIG. 5, for example, the radiation curable resin 18 is shaken off by accelerating to a rotational speed of 1500 rpm.
(4) The light-shielding mask 60 is removed, and the radiation 15 is irradiated to the uncured radiation curable resin 18 at the outer peripheral edge of the substrate 11 (FIG. 5: rotation speed 0). Curing (final curing) (S04).
The optical information recording medium can be manufactured by the above procedure.

Next, step S01 for applying the radiation curable resin 18 on the substrate 11 will be described with reference to FIG.
(A) First, a substrate 11 having a signal recording layer 12 is prepared. As this substrate 11, for example, as shown in FIG. 6A, a substrate 11 having a thickness of approximately 1.1 mm, a diameter of approximately 120 mm, and a center hole diameter of approximately 15 mm can be used. The substrate 11 is made of polycarbonate and is formed by injection molding. In addition, the board | substrate 11 may be formed from another resin materials, such as an acryl and polyolefin, for example other than a polycarbonate. The signal recording layer 12 is made of an Ag alloy or a thin film such as Al having a thickness of about 40 nm on the pit formed on the substrate 11.
(B) Next, as shown in FIG. 6B, the substrate 11 is set on the turntable 20, and the center hole of the substrate 11 is closed with a cap 17.
(C) Next, about 2 g of radiation curable resin 18 having a viscosity of about 2000 mPa · s is dropped on the cap 17, and the rotation speed of the substrate 11 is extended at about 3300 rpm for about 1.5 seconds.
(D) Thereafter, the rotation of the substrate 11 is stopped, and after the application of the radiation curable resin 18 by stretching (also referred to as spin coating) is completed, the cap 17 is removed.
By the above procedure, the step of applying the radiation curable resin 18 on the substrate 11 can be performed. In this case, as shown in FIG. 6C, in the state where the number of rotations of the substrate 11 is stopped after the stretching of the radiation curable resin 18, the outer periphery is caused by the surface tension of the radiation curable resin 18 on the substrate 11. The swell of the resin 18 may occur in a region near the end.

Next, after accelerating the number of rotations of the substrate 11, after reaching a predetermined number of rotations, decelerating and irradiating radiation during the deceleration of the number of rotations to cure the radiation curable resin, the flowchart of FIG. It explains using.
(A) First, the rotational speed of the substrate 11 is accelerated (S11).
(B) It is determined whether or not the rotational speed has reached a predetermined rotational speed (S12). When the rotation speed of the substrate 11 has reached the predetermined rotation speed, the process proceeds to the next step S13. On the other hand, when the rotation speed of the substrate 11 does not reach the predetermined rotation speed, the process returns to the acceleration step S11 again.
(C) If the rotation speed of the substrate 11 has reached the predetermined rotation speed, the rotation speed is decelerated (S13). By accelerating the number of rotations of the substrate 11 to a predetermined number of rotations, it is possible to suppress the swell of the resin 18 that occurs in the region near the outer peripheral end described above.
(D) While the rotational speed of the substrate 11 is being reduced, the radiation curable resin 18 on the substrate 11 is irradiated with radiation 15 from the radiation lamp 40 through the light shielding mask 60 to cure the radiation curable resin 18 (S14). ). In addition, when a radiation is irradiated during the acceleration of the rotation speed of the substrate 11 as in the prior art, a thorn-like burr may occur at the outer peripheral end. This is presumably because the radiation curable resin 18 at the outer peripheral edge of the substrate 11 is irradiated with the radiation while it is about to be shaken off by the acceleration of the rotation speed of the substrate 11 and cured. In the method for manufacturing an optical information recording medium according to the present invention, the radiation curable resin 18 is cured by irradiating radiation while the rotational speed of the substrate 11 is reduced as described above. It is considered that the generation of burrs can be suppressed. Further, in the method for manufacturing an optical information recording medium of the present invention, the radiation curable resin 18 on the substrate 11 is irradiated with the radiation 15 through the light shielding mask 60 so that the outer peripheral edge of the substrate 11 is not irradiated with the radiation. Shielded from light. As a result, the radiation curable resin 18 that is about to be shaken off at the outer peripheral end portion of the substrate 11 is shaken off without being cured, so that it is considered that the generation of the burr can be suppressed.
By the above procedure, step S02 can be performed in which the radiation curable resin 18 is cured by irradiation with radiation while the rotational speed of the substrate 11 is reduced.

  Although the light shielding mask 60 is used here, it is not always necessary to use the light shielding mask 60 in the method for manufacturing an optical information recording medium according to the present invention. For example, by using a linear light source or the like as the radiation lamp 40, the radiation 15 is irradiated only to the radiation curable resin 18 on the substrate 11, so that the radiation curable resin 18 at the outer peripheral edge of the substrate 11 is not irradiated. For example, the light shielding mask 60 may not be used. When the light shielding mask 60 is used, it is possible to reliably prevent the radiation curable resin 18 shaken off from the substrate 11 from being exposed to the radiation 18, so that the excess radiation curable resin 18 can be recycled. Benefits are gained.

Further, the step S03 of shaking off the excess radiation curable resin 18 at the outer peripheral end of the substrate 11 will be described with reference to the flowchart of FIG.
(A) The number of rotations of the substrate 11 is accelerated again (S21).
(B) It is determined whether or not the rotational speed of the substrate 11 has reached a predetermined rotational speed (S22). If the predetermined rotational speed has not been reached, the process returns to step S21 to further accelerate the rotational speed of the substrate 11. On the other hand, if the rotational speed has reached the predetermined rotational speed, the process proceeds to the next step S23. The predetermined number of rotations is preferably higher than the number of rotations during resin application or radiation irradiation. For example, it is 1500 rpm-10000 rpm, More preferably, it is 2000 rpm-9000 rpm.
(C) If the number of rotations of the substrate 11 reaches a predetermined number of rotations, the excess radiation curable resin 18 at the outer peripheral end of the substrate 11 can be shaken off (S23).
As described above, the step S03 of shaking off the excess radiation curable resin 18 at the outer peripheral end of the substrate 11 can be performed.

  This swing-off process will be further described. Although the above-described step of curing the radiation curable resin 18 by irradiation with radiation while the rotation speed of the substrate 11 is being reduced, a substantial portion of the swell of the radiation curable resin 18 in FIG. 6C is removed, but FIG. As shown in FIG. 4B, there are cases where the radiation curable resin 18 that is uncured and has an excess of radiation is formed in the vicinity of the outer peripheral edge of the substrate 11 that has not been irradiated with radiation by the light shielding mask 60. In some cases, the protrusions having a convex shape are approximately 50 μm. If such a protrusion is present, if a load is applied to this portion when the optical information recording medium is handled, the light transmission layer may be peeled off. Therefore, in the swing-off step S03, the rotation speed of the substrate 11 is accelerated again, and the extra radiation curable resin 18 is shaken off by further high-speed rotation. By performing the swing-off, a light transmission layer having a uniform thickness can be formed up to the vicinity of the outer peripheral end portion of the substrate 11, and a highly reliable optical information recording medium can be provided.

  Depending on the amount of resin to be shaken off, a light transmission layer having a step near the outer peripheral end of the substrate 11 can be formed as shown in FIG. 9B. In this case, it is preferable that the radiation curable resin 18 in the vicinity of the outer peripheral end portion of the substrate 11 does not completely disappear even after the shaking is performed. Further, since the strength decreases even if the thickness of the light transmission layer is too thin, the thickness of the light transmission layer in the vicinity of the outer peripheral edge is preferably 3 μm or more, more preferably 10 μm or more and 90 μm or less. In addition, the said level | step difference can be 10 micrometers or more, for example. Furthermore, if the reflective film or the like formed on the signal recording layer is exposed to the atmosphere, the risk of corrosion due to oxidation or the like becomes very high. Therefore, the step is preferably outside the signal area, that is, a radius of 58.6 mm or more, and more preferably 59.0 mm or more. Further, it is preferable that the signal recording layer 12 is covered with the resin 18 having a slight thickness even after the resin 18 is shaken off.

Further, a process S04 in which the light shielding mask 60 is removed and the uncured radiation curable resin 18 at the outer peripheral edge of the substrate 11 is irradiated with radiation to be cured will be described. As described above, after accelerating the number of rotations of the substrate 11 and shaking off the excess radiation curable resin at the outer peripheral edge of the substrate, it is located under the light shielding mask 60 and is not present at the outer peripheral edge of the substrate 11. It is necessary to cure the curing radiation curable resin 18. For this purpose, after removing the light shielding mask 60, the outer peripheral edge of the substrate 11 is irradiated with radiation 15 to cure the uncured radiation curable resin (final curing). For example, in the example of the timing chart of FIG. 5, after the number of rotations of the substrate is set to 0, radiation is irradiated and final curing is performed. In addition, the timing which irradiates a radiation for final hardening is not restricted to the case of said example.
As described above, the step S04 of irradiating and curing the uncured radiation curable resin 18 at the outer peripheral edge of the substrate 11 can be performed.

  Through the above steps S01 to S04, the method for manufacturing an optical information recording medium according to the present invention can be performed. In the method for manufacturing an optical information recording medium according to the present invention, the radiation curable resin 18 is cured by irradiating with radiation during the step S01 of applying the radiation curable resin 18 on the substrate 11 and the rotation speed of the substrate 11 being reduced. The step S02 is essential, but the step S03 of shaking off the radiation curable resin 18 is not essential. That is, in the step S02 in which the radiation curable resin is cured by irradiating radiation while the number of rotations of the substrate 11 is reduced, if the resin 18 can be sufficiently shaken off by the first acceleration, the shaking off step S03 is performed. There is no need. In this case, it is not necessary to perform the step S04 of irradiating and curing the uncured radiation curable resin 18 on the outer peripheral edge of the substrate 11 thereafter.

Further, another example of the method for manufacturing the optical information recording medium will be described with reference to the flowchart of FIG. Compared with the case of FIG. 7, the manufacturing method of the optical information recording medium of this other example is compared with the case of FIG. 7 in the step S02 in which the radiation curable resin is cured by irradiating radiation while the rotation speed of the substrate 11 in FIG. The difference is that the radiation is irradiated after decelerating from the first rotational speed to the second rotational speed.
(A) First, the rotational speed of the substrate 11 is accelerated (S31).
(B) It is determined whether or not the rotational speed has reached the first rotational speed (S32). When the rotation speed of the substrate 11 has reached the first rotation speed, the process proceeds to the next step S33. On the other hand, when the rotation speed of the substrate 11 has not reached the first rotation speed, the process returns to the acceleration step S31 again.
(C) If the rotation speed of the substrate 11 has reached the first rotation speed, the rotation speed is decelerated (S33). By accelerating the rotation speed of the substrate 11 to the first rotation speed, it is possible to suppress the swell of the resin 18 that occurs in the region near the outer peripheral edge described above.
(D) It is determined whether or not the rotational speed has reached the second rotational speed (S34). When the rotation speed of the substrate 11 has reached the second rotation speed, the process proceeds to the next step S35. On the other hand, when the rotation speed of the substrate 11 has not reached the second rotation speed, the process returns to the deceleration step S33 again. In this case, feedback control is performed instantaneously, and the second rotational speed is quickly reached.
(E) After the number of rotations of the substrate 11 is reduced to the second number of rotations, the radiation curable resin 18 on the substrate 11 is irradiated with the radiation 15 from the radiation lamp 40 through the light shielding mask 60, and radiation curable. The resin 18 is cured (S35).
By the above procedure, after the rotation speed of the substrate 11 is reduced from the first rotation speed to the second rotation speed, the radiation curing resin 18 can be cured by irradiating with radiation S02.

  In this another example of the method for manufacturing an optical information recording medium, after the rotational speed of the substrate 11 is reduced from the first rotational speed to the second rotational speed as described above, the radiation curable resin 18 is irradiated with radiation. Harden. Hereinafter, the first and second rotation speeds (irradiation timing) and the thickness unevenness of the radiation curable resin at the outer peripheral edge of the substrate will be considered.

  First, the effect of using a light shielding mask will be described. When the light shielding mask 60 is used, if the radiation curable resin 18 is cured while rotating the substrate 11, the air is directed further outward from the inner peripheral side of the substrate 11 through the outer periphery of the substrate 11 and the light shielding mask 60. May occur. At that time, since the space between the light shielding mask 60 and the outer periphery of the substrate 11 is narrow, the flow of air becomes strong, and the radiation curable resin 18 is thinned near the outer peripheral end of the substrate 11 by the force of the air flow. The tendency to become is seen.

  Next, the case of irradiating radiation while accelerating the rotation speed of the substrate 11 according to the prior art will be described. When the irradiation timing for irradiating the radiation during the acceleration of the rotation speed is variously changed, when the light shielding mask 60 is not used, burrs are generated at the outer peripheral edge of the substrate as described above. On the other hand, when the light shielding mask 60 is used, the air flow is added to the rotation of the substrate 11 due to the influence of the light shielding mask 60 as described above, and the force for pushing the radiation curable resin 18 toward the outer periphery of the substrate becomes too strong. The radiation curable resin 18 is considered to have a shape as shown in FIG. In this case, with respect to the irradiation timing during acceleration, the radiation irradiation was performed with the magnitude of the acceleration and the number of rotations lowered, but there is a tendency that the thickness unevenness increases. For example, when curing is performed by UV irradiation when the rotational speed reaches approximately 800 rpm when accelerating at 200 rpm / second, as shown in FIG. 11B, the thickness near the shading mask is increased, but immediately after stretching. In addition, the bulge in FIG. 11 (b) generated at the outer peripheral portion of the substrate is not sufficiently eliminated.

  Therefore, in another example of the method for manufacturing an optical information recording medium according to the present invention, after reducing the number of rotations of the substrate from the first number of rotations to the second number of rotations, the radiation is irradiated through the light shielding mask 60 and the radiation is irradiated. The first rotation speed and the second rotation speed when the curable resin is cured will be examined. In the above example, after accelerating at 300 rpm / second and rotating until the rotational speed reaches 1200 rpm (first rotational speed), the speed is reduced at −300 rpm / second and the rotational speed is 900 rpm (second rotational speed). ) When it reaches). FIG. 11C shows a state in the vicinity of the outer peripheral edge of the substrate at that time. In this case, the thickness unevenness seen in FIGS. 11A and 11B is eliminated, and a very uniform layer is formed. This is once accelerated to 1200 rpm (first rotation speed), so that the swell of the resin 18 on the outer peripheral portion of the substrate 11 is eliminated by centrifugal force or the like (state of FIG. 11A), and further 900 rpm (second speed). It is considered that the radiation curable resin 18 below the light-shielding mask 60 is pulled back in the inner peripheral direction of the substrate 11 by decelerating the rotation speed to the rotation speed.

  Further, some studies are made on the number of rotations when the light shielding mask 60 is used. The rotational speed is changed while maintaining the principle that the rotational speed is once accelerated and then decelerated and then cured. In the embodiment described above, the irradiation is performed by increasing the rotation to 1200 rpm in 4 seconds and then decreasing the rotation to 900 rpm in 1 second. On the other hand, for example, the rotation is increased to 1500 rpm in 4 seconds, and then the rotation is decreased to 800 rpm. In addition, since the absolute value of thickness will become small depending on the combination of rotation speed, the thickness to apply | coat is adjusted beforehand so that the absolute value of thickness obtained in each combination may become substantially the same. When searching for a condition in which the thickness distribution is, for example, 4 μm or less by a plurality of combinations, the thickness is determined by how much the rotational speed is lowered (second rotational speed) rather than the rotational speed that is once increased (first rotational speed). It can be seen that it has a great effect on unevenness. Since it is naturally assumed that the rotation speeds (first and second rotation speeds) vary depending on the viscosity of the radiation curable resin to be used, it is preferable to select an optimum range according to the viscosity. In the case of the viscosity of about 2000 mPa · s used in this example, the rotation speed (second rotation speed) at the time of radiation irradiation is preferably 400 rpm or more and 1000 rpm or less.

  Next, the time required to increase the rotational speed up to the first rotational speed is also examined. In this case, the same result can be obtained for all combinations of the above rotational speeds. That is, if the time for increasing the rotation speed is too short (acceleration is too large), the force due to acceleration increases, and the radiation curable resin at the outer peripheral edge of the substrate tends to be shaken off too much, resulting in uneven thickness. NG. On the other hand, even if it takes time to increase the rotation, the thickness unevenness is not affected. In addition, since the absolute value of thickness will become small when rotation speed is too large, the thickness to apply | coat is adjusted beforehand so that the absolute value of thickness obtained in each combination may become substantially the same.

  Furthermore, with regard to the time required to reduce the rotational speed from the first rotational speed to the second rotational speed, if the time is too short, that is, if the deceleration is too early, the effect of reducing the rotational speed is less likely to appear. . On the other hand, if the time is too long, that is, if the deceleration is too slow, the effect of increasing the number of revolutions once fades, so there is an optimum range. In this embodiment, the time from when reaching the maximum number of rotations (first number of rotations) until reaching the second number of rotations (at the time of radiation irradiation) is 0.3 seconds or more and less than 2 seconds. It is preferable. In producing an optical information recording medium, it is preferable that a high quality product can be produced with as short a tact as possible and stably. For example, if the combination is as shown in FIGS. 12A and 12B, production can be performed with a high yield. In the example of FIG. 12A, the first rotation speed is 1000 rpm (after 3 seconds), and the second rotation speed is 700 rpm (after 4 seconds from the beginning, after 1 second from the first rotation speed). It is. In the example of FIG. 12B, the first rotation speed is 1500 rpm (after 1.5 seconds), and the second rotation speed is 700 rpm (after 2 seconds from the beginning, from the first rotation speed to 0. 0). 5 seconds later).

  As yet another example, the substrate 11 may be irradiated with radiation while the number of rotations of the substrate 11 is decelerated to the second number of rotations and then held at the second number of rotations (here, 900 rpm) for a certain period of time. In this case, there is a tendency that the effect of uniforming the thickness unevenness is lost little by little as the time from the time when the speed is changed to the constant speed state becomes longer. Therefore, the radiation curable resin 18 may be cured by irradiating the radiation 15 while maintaining a certain rotational speed after the rotational speed of the substrate 11 is reduced. More preferably, the radiation curable resin 18 is cured by irradiating 15.

  In this embodiment, the radiation curable resin 18 having a viscosity of 2000 mPa · s was used. However, the viscosity of the radiation curable resin 18 to be used is not limited to the above case, and the desired thickness of the light transmission layer and the recording film What is necessary is just to select suitably according to the magnitude | size of an unevenness | corrugation. Moreover, what is necessary is just to determine the rotation speed at the time of extending | stretching (spin coating), hardening (spin cure), and resin shaking according to the viscosity of the radiation curable resin 18 to be used. When the viscosity of the resin 18 is high, the rotational speed may be several hundred rpm to about 10,000 rpm. When using radiation curable resins 18 having different viscosities, it is preferable to select an optimum rotation speed and rotation time in accordance with the viscosities.

  The light transmission layer is preferably substantially transparent to the wavelength of the laser that performs recording / reproduction. The optical information recording medium of the present embodiment performs recording / reproduction with a laser having a wavelength of about 405 nm, and a medium having a transmittance of 90% or more with respect to this wavelength can be used.

  Here, as an example, a read-only optical information recording medium is shown in which a reflective film made of Al or Ag alloy or a light transmission layer is laminated on a substrate on which pits are formed. However, the present invention is not limited to these examples. . The optical information recording medium manufacturing method according to the present invention includes, for example, a rewritable recording / reproducing type in which a thin film such as a phase change recording film and a light transmission layer are laminated on a substrate on which pits or groove grooves are formed, It can also be applied to the production of a write-once type optical information recording medium capable of recording only once.

(Embodiment 2)
A method for manufacturing an optical information recording medium according to Embodiment 2 of the present invention will be described. This optical information recording medium manufacturing method is different from the optical information recording medium manufacturing method according to Embodiment 1 in that a protective layer made of a radiation curable resin is formed instead of a light transmitting layer. Note that overlapping description of portions similar to those described in Embodiment 1 is omitted. When the light transmission layer is formed of a radiation curable resin as in the optical information recording medium manufactured in Embodiment 1, in order to reduce the warp of the optical information recording medium due to the curing shrinkage of the radiation curable resin, It is conceivable to design the radiation curable resin softly, for example, with a pencil hardness of about HB or B. At this time, it is assumed that the light transmission layer is too soft and the surface of the light transmission layer is damaged when the optical information recording medium is handled, thereby affecting the recording / reproduction characteristics. Therefore, as shown in FIG. 13, it is preferable to provide a protective layer 21 on the light transmission layer 13. The hardness of the protective layer 21 is preferably pencil hardness H or more from the viewpoint of preventing scratches, and is excellent in antifouling properties so that fingerprints and the like do not adhere. Here, the pencil hardness can be determined based on whether the tip of the pencil is sharpened, pressed with a load of 1 kg at an angle of 45 degrees, and the pencil is pulled while the load is applied to determine whether or not the scratch is made. The pencil hardness is measured according to JIS-K5400.

  In the method for manufacturing an optical information recording medium according to Embodiment 2 of the present invention, as in the case of forming a light transmission layer made of a radiation curable resin in the method for manufacturing an optical information recording medium according to Embodiment 1, A protective layer 21 made of a radiation curable resin can be formed.

(Embodiment 3)
A method for manufacturing an optical information recording medium according to Embodiment 3 of the present invention will be described. This optical information recording medium manufacturing method is different from the optical information recording medium manufacturing method according to the first embodiment in that it is a manufacturing method of a multilayer optical information recording medium having a plurality of signal recording layers. . That is, in this method for manufacturing an optical information recording medium, in the same manner as the formation of the light transmission layer made of a radiation curable resin in the method for manufacturing the optical information recording medium according to Embodiment 1, a plurality of signal recording layers are provided. An intermediate layer can be formed. In addition, the overlapping description is abbreviate | omitted about the part similar to the part demonstrated in Embodiment 1 and 2. FIG.

  In the above embodiments, a so-called single-layer optical information recording medium having only one signal recording layer has been described. However, a so-called multilayer optical information recording having two or more signal recording layers. The method for producing an optical information recording medium according to the present invention is also effective for the medium. For example, FIG. 14A is a cross-sectional view showing the configuration of a two-layer optical information recording medium. This two-layer type optical information recording medium has an intermediate layer 309 of about 25 μm between the signal recording layers 302 and 312, and the thickness of the light transmission layer 303 is about 75 μm. FIG. 14B is a schematic cross-sectional view showing a configuration of an optical information recording medium of a four-layer type optical information recording medium. This four-layer type optical information recording medium has intermediate layers 309, 319, and 329 of about 15 μm between the signal recording layers 302, 312, 322, and 332, and the thickness of the light transmission layer 303 is about 55 μm. In the two-layer optical information recording medium and the four-layer optical information recording medium, not only the light transmission layer 303 but also the intermediate layers 309, 319, and 329 can be formed by the same method as in the first embodiment. it can.

Next, specific examples of the method for manufacturing the optical information recording medium will be described below.
(A) First, a radiation curable resin 308 is applied on the signal recording layer 302 of the substrate 301. Here, a radiation curable resin of about 200 mPa · s is used, and stretching is performed for about 3 seconds at about 2000 rpm using the cap 17 as in the first embodiment.
(B) Next, the substrate 301 is accelerated to a predetermined rotational speed, decelerated, and radiation is irradiated through the light shielding mask 60 while the rotational speed is decelerated to cure at least a part of the radiation curable resin. For example, a light shielding mask 60 having a hole with a diameter of φ118 mm is used. Further, the substrate 301 is accelerated at 150 rpm / second by rotating the substrate 301 up to 600 rpm, and then irradiated with radiation when the rotation speed is reduced to −150 rpm / second and then reaches 400 rpm. In this embodiment, a pulse irradiation type UV irradiator (Xenon RC-747 type) is used, and one pulse is irradiated for several tens of ms. In addition, in order to transfer a signal to this radiation curable resin, at this time, it is necessary that the radiation curable resin is not completely cured and the surface remains uncured. For example, the surface can be brought into an uncured state by lowering the intensity of radiation, but if it is still hardened, the degree of curing can be adjusted by changing the atmosphere irradiated with radiation. Since the radiation curable resin used in this example has a property that the curing is inhibited in an oxygen-excessive atmosphere, an uncured state can be stably produced by increasing the oxygen concentration in the atmosphere.
(C) A stamper 310 having grooves and uneven pits to be formed is pressed against the uncured surface of the radiation curable resin as shown in FIG. For example, the stamper 310 and the substrate 301 can be brought into close contact with each other by using a roller or the like. In this case, when bubbles are mixed between the stamper 310 and the substrate 301, it is preferable to press both in a vacuum.
(D) Radiation is irradiated while pressing the stamper 310 to completely cure the radiation curable resin 308.
(E) After the radiation curable resin 308 is completely cured, the stamper 310 is peeled off to form an intermediate layer 309 having a thickness of about 25 μm as shown in FIG. A polyolefin substrate that is transparent to radiation can be used as the stamper 310. Note that the stamper 310 may not be transparent as long as the substrate 301 and the signal recording layer 302 formed in advance on the substrate 301 are transparent to radiation. For example, a metal stamper can be used.
(F) After the stamper 310 is peeled off, a signal recording layer can be formed by forming a metal film or the like on the formed grooves and irregularities.
(G) Thereafter, the above steps (a) to (f) are repeated to produce the light transmission layer 303, whereby a multilayer optical information recording medium can be produced.

  In addition, application | coating conditions can be changed or the viscosity of the radiation curable resin to be used can be changed with the thickness of the light transmission layer and intermediate | middle layer to produce. Further, in the present embodiment, after applying the radiation curable resin, once irradiated with radiation, the radiation curable resin was partially cured and then a stamper was applied, and further irradiated with radiation and completely cured, It is not limited to this. For example, after applying the radiation curable resin, a stamper may be attached without irradiating the radiation, and then the radiation curable resin may be cured by irradiating the radiation.

  In this method for manufacturing an optical information recording medium, a protective layer made of a radiation curable resin may be further formed in the same manner as the method for manufacturing an optical information recording medium described in the second embodiment. Furthermore, these multilayer optical information recording media are of a rewritable recording / reproducing type, a write-once type that can be recorded only once, or a reproduction-only type in which the reflective layer is mainly composed of Al or Ag. May be.

  The embodiments of the present invention have been described above by way of examples. However, the present invention is not limited to the above embodiments, and can be applied to other embodiments based on the technical idea of the present invention.

  The method for producing an optical information recording medium and the optical information recording medium according to the present invention are useful for a method for producing an optical information recording medium having a light transmission layer, an intermediate layer, a protective layer and the like made of a radiation curable resin.

It is a block diagram which shows the structure of the manufacturing apparatus of the optical information recording medium which concerns on Embodiment 1 of this invention. (A) It is a top view which shows the positional relationship of a light shielding mask and a board | substrate, (b) is a schematic sectional drawing of (a). (A) And (b) is a schematic sectional drawing which shows the positional relationship with a board | substrate at the time of using the light shielding mask from which a shape differs. It is a flowchart of the manufacturing method which concerns on Embodiment 1 of this invention. It is a time chart which shows the relationship between the time in the manufacturing method which concerns on Embodiment 1 of this invention, and the rotation speed of a board | substrate. (A)-(c) is a schematic sectional drawing which shows the application | coating process of the radiation curable resin of step S01 of FIG. It is a flowchart which shows the detail of the process of irradiating a radiation while decelerating the rotation speed of the board | substrate of FIG.4 S02, and hardening | curing radiation-curable resin. It is a flowchart of the swing-off process of step S03 of FIG. (A) is sectional drawing which shows the state of the radiation curable resin in the outer peripheral end vicinity of the optical information recording medium before performing the swing-off process in the manufacturing method of the optical information recording medium which concerns on Embodiment 1 of this invention. FIG. 6B is a cross-sectional view showing the state of the radiation curable resin in the vicinity of the outer peripheral end portion of the optical information recording medium after performing the swing-off process. It is a flowchart of another example of step S02 in the manufacturing method of the optical information recording medium which concerns on Embodiment 1 of this invention. (A)-(c) is sectional drawing which shows the mode of distribution of the radiation-curable resin in the outer periphery edge part vicinity of the optical information recording medium in Embodiment 1 of this invention. (A) And (b) is each time chart in the case of performing radiation irradiation, changing acceleration and deceleration of the rotation speed of a board | substrate. It is sectional drawing of the optical information recording medium in which the protective layer in Embodiment 2 of this invention was formed. (A) is sectional drawing which shows an example of the two-layer type optical information recording medium in Embodiment 3 of this invention, (b) is sectional drawing which shows an example of a four-layer type optical information recording medium It is. (A)-(b) is sectional drawing which shows each process of intermediate | middle layer formation in the manufacturing method of the optical information recording medium based on Embodiment 3 of this invention.

Explanation of symbols

11, 301 Substrate 12, 302, 312, 322, 332 Signal recording layer 13, 303 Light transmission layer 15 Radiation 17 Cap 18 Radiation curable resin 20 Rotary table 21 Protective layer 30 Motor 40 Radiation lamp 50 Control unit 60, 60a Light shielding mask 304 Groove or uneven pit 308 Partially cured radiation curable resin 309, 319, 329 Intermediate layer 310 Stamper

Claims (17)

A method for producing an optical information recording medium comprising a substrate having at least one signal recording layer and a resin layer that transmits light,
Applying a radiation curable resin on the substrate;
After accelerating the number of revolutions of the substrate and reaching the first number of revolutions, the number of revolutions is decelerated and radiation is applied during the deceleration of the number of revolutions to cure at least a portion of the radiation curable resin. Forming a resin layer, and a method for manufacturing an optical information recording medium.   In the step of forming the resin layer, after reaching a second rotational speed lower than the first rotational speed, the resin layer is formed by irradiating with radiation to cure at least a part of the radiation curable resin. The method of manufacturing an optical information recording medium according to claim 1.   In the step of forming the resin layer, the resin layer is formed by irradiating with radiation while rotating the substrate at the second rotation speed for a predetermined time to cure at least a part of the radiation curable resin. The method for producing an optical information recording medium according to claim 2.   In the step of forming the resin layer, a light shielding mask having a circular hole having an inner diameter equal to or smaller than the outer diameter of the substrate is arranged such that the hole of the light shielding mask is concentrically arranged with the substrate. The optical information recording medium according to claim 1, wherein the substrate is irradiated with radiation through the light shielding mask to cure at least a part of the radiation curable resin to form a resin layer. Production method.   After the step of forming the resin layer, a step of accelerating the number of rotations of the substrate to a predetermined number of rotations higher than the first number of rotations and further shaking off the radiation curable resin at the outer peripheral edge of the substrate The method of manufacturing an optical information recording medium according to claim 4, comprising:   After the step of shaking off the radiation curable resin at the outer peripheral end of the substrate, the method further includes the step of irradiating the outer peripheral end of the substrate with radiation to cure the radiation curable resin at the outer peripheral end of the substrate. 6. The method of manufacturing an optical information recording medium according to claim 5,   The method for manufacturing an optical information recording medium according to claim 1, wherein the step of applying the radiation curable resin is performed by a spin coating method.   2. The optical information recording according to claim 1, wherein, in the step of applying the radiation curable resin, the substrate having a central hole is used to block the central hole and apply the radiation curable resin to the substrate. A method for producing a medium.   The method for producing an optical information recording medium according to claim 1, wherein the resin layer is a light transmission layer provided on the signal recording layer.   The method for producing an optical information recording medium according to claim 1, wherein the resin layer is a protective layer.   The method for producing an optical information recording medium according to claim 1, wherein the resin layer is an intermediate layer provided between a plurality of signal recording layers. After the step of forming the resin layer,
A step of applying a stamper having grooves or concave and convex pits to the radiation curable resin obtained by curing at least a part of the substrate, and further irradiating with radiation to cure the radiation curable resin to form an intermediate layer. The method of manufacturing an optical information recording medium according to claim 11, further comprising: A turntable for rotatably holding a substrate coated with radiation curable resin on the surface;
A motor for rotating the rotary table;
A radiation lamp for irradiating the radiation curable resin on the substrate with radiation to cure at least a part of the radiation curable resin;
An apparatus for manufacturing an optical information recording medium, comprising: a control unit that controls a rotation speed of the motor and an irradiation timing of radiation of the radiation lamp. A light-shielding mask having a circular hole having an inner diameter equal to or smaller than the outer diameter of the substrate, and is viewed from the radiation lamp without being in contact with the substrate between the substrate and the radiation lamp. A light-shielding mask arranged so that the hole is concentric with the substrate,
The optical information recording medium manufacturing apparatus according to claim 13, wherein the substrate is irradiated with radiation from the radiation lamp through the light shielding mask.   The controller accelerates the rotational speed of the motor, reaches the first rotational speed, decelerates, and reduces the radiation lamp to the radiation curable resin on the substrate during the rotational speed reduction. The apparatus for producing an optical information recording medium according to claim 13, wherein radiation is irradiated.   The controller accelerates the rotational speed of the motor, reaches the first rotational speed, decelerates, reaches a second rotational speed lower than the first rotational speed, and then from the radiation lamp. The apparatus for producing an optical information recording medium according to claim 13, wherein radiation is irradiated. An optical information recording medium manufactured by the manufacturing method according to claim 1,
The optical information recording medium according to claim 1, wherein a thickness of the resin layer in the vicinity of an outer peripheral end portion of the substrate is 10 μm or more thinner than an average thickness of the entire resin layer on the substrate.

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