JP2003047906A - Method for manufacturing disc-like recording medium and applying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a disc-like recording medium by applying a coating solution uniformly. SOLUTION: The method for manufacturing the disc recording medium, which uses a system provided with a turntable 2 that is able to mount a disc- like optical disc D and a disc-like component 4 which is mounted in the center part of the optical disc D of which the center part is located at the center part of the turntable 2, comprises spin-coating the coating solution R added dropwise on the surface of the optical disc D with centrifugal force caused by the rotation of the turntable 2 through rotating the turntable 2 in the state that the optical disc D and the disc-like component 4 are being mounted and adding the coating solution R at the dropping position in the proximity of the center part on the upper surface of the disc-like component 4, and the method is characterized by controlling the speed of rotation of the turntable 2 in accordance with the period of time between the predetermined point after initiating to drop the coating solution R and the point at which the coating solution R reaches the first predetermined position prescribed in advance on the disc-like component 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a disc-shaped recording medium in which a coating liquid such as a resin is spin-coated at the time of producing a disc-shaped recording medium such as a CD or a DVD, and a coating liquid for spin coating. It relates to the device.

[0002]

2. Description of the Related Art A disk-shaped recording medium such as a CD and a DVD (hereinafter also referred to as "optical disk") is provided with a protective layer for preventing scratches or corrosion of a recording layer and a reflective layer. This protective layer is formed into a thin film by coating and curing a coating liquid such as a photo-curing resin so as to cover the entire recording layer. Furthermore, recently, as disclosed in, for example, Japanese Patent Application Laid-Open No. 8-235638, a support layer (protective layer) that does not require light transmission, that is, a support layer that does not require an optical thickness is formed by injection molding as a disk substrate. After forming a thick film on the information recording surface side of this disc substrate, a reflective film provided to make it reproducible, or a recording layer made to be recordable, etc. is formed, and then a recording / reproducing laser beam is further formed thereon. An optical disk manufactured by laminating a light transmitting layer made of a transparent resin layer capable of transmitting light has also attracted attention. This light transmitting layer is also formed into a thin film slightly thicker than the above-mentioned protective layer by similarly applying a coating liquid such as a light curable resin and curing it.

In these cases, a spin coating method is generally used as a method for applying the coating liquid. In addition, in a coating apparatus that applies a coating liquid by this spin coating method, generally, a recording medium (or a disk substrate) having a mounting center hole is placed on a turntable that rotates about its central portion as a rotation axis. While placing and rotating, drop the coating liquid at any position on the outer peripheral side of the mounting center hole,
In that state, by controlling the rotation of the turntable, the coating liquid is applied to the entire surface of the recording medium or the like to secure a desired layer thickness. In this case, when the ultraviolet curable resin is applied, the resin layer is formed by subsequently irradiating with ultraviolet rays to solidify the resin.

In addition to such a general resin layer forming apparatus, as one of the characteristic manufacturing methods, a disk-shaped member that covers the mounting center hole of the optical disk is placed and the resin is dropped on it. A method of spin coating has been developed. According to this method, since it is easy to control the layer thickness of the resin layer substantially uniformly in the radial direction, the above-mentioned JP-A-8-23563.
It is also applied to the formation of the light transmitting layer disclosed in Japanese Patent No.

When the coating liquid is applied to the optical disk by the spin coating method, first, the optical disk is placed on the turntable in the application device, and it is not necessary to form a resin layer in the central portion of the placed optical disk. Set a disk-shaped member that covers the large area. Next, for example, the air below the disk-shaped member is sucked by an air pump to draw the disk-shaped member toward the turntable. As a result, the disk-shaped member is placed in close contact with the optical disk on the turntable in an appropriate manner. Next, the turntable in this state is rotated at a rotation speed of 25 rpm, for example, and a prescribed amount of the coating liquid is dropped on the upper surface of the disk-shaped member. At this time, the coating liquid moves on the disk-shaped member in the radial direction of the optical disk (that is, the radial direction of the disk-shaped member) by the centrifugal force generated by the rotation of the turntable. Then, the rotation speed of the turntable is increased to, for example, 2 rpm.
Rotate at a constant rotation speed of 000 rpm for a while. As a result, the coating liquid that has moved on the disk-shaped member moves from the outer edge of the disk-shaped member to the upper surface of the optical disk, and moves its surface toward the outer edge. Further, the excess coating liquid that has reached the outer edge of the optical disc is scattered from the optical disc by the centrifugal force. As a result, the coating liquid is applied in a thin film on the entire surface of the optical disc. After this, stop the turntable,
The optical disk on which the coating liquid has been applied is removed from the coating device, and the coating liquid is cured by a predetermined curing process. As a result, a thin resin layer is formed on the surface of the optical disc, and the optical disc is completed.

[0006]

However, the above optical disc manufacturing method has the following problems. That is,
In the above-mentioned manufacturing method, when the coating liquid is applied to the optical disc, a predetermined amount of the coating liquid is dropped on the disk-shaped member, and the turntable is rotated at a constant speed for a while, for example, at a rotation speed of 2000 rpm. , The coating liquid is spread over the entire surface of the optical disc. In this case, the coating liquid used to form the resin layer, depending on the ambient temperature and humidity during coating,
Its viscosity changes sequentially. Therefore, even if a constant amount of the coating liquid is always dropped, the amount of the coating liquid slightly changes due to the change in the viscosity of the coating liquid itself. In addition, when the viscosity of the coating liquid is high and when it is low, how the coating liquid spreads when the turntable is rotated at a rotation speed of 2000 rpm (until the disk-shaped member reaches the outer edge of the optical disc). Time) is different. Therefore, the conventional manufacturing method has a problem that it is difficult to uniformize the film thickness of the resin layer for each product due to the change in the amount of the coating liquid dropped and the viscosity at the time of dropping. .

In this case, for example, an optical disc for inspection is arbitrarily extracted from a large number of optical discs manufactured one after another, the thickness of the resin layer in the optical disc for inspection is measured, and the measured value is obtained. A method of controlling the rotation speed during constant speed rotation can be considered according to. Specifically, when the thickness of the resin layer in the extracted optical disc exceeds the specified value, the reference rotation speed (for example, 2 minutes per minute) during constant-speed rotation is used.
The rotation speed is higher than the standard rotation speed (000 rotations), and when the rotation speed is less than the specified value, the rotation speed is lower than the reference rotation speed when rotating at a constant speed to change the centrifugal force applied to the dropped coating liquid and spread the coating liquid. To control. As a result,
Even if the viscosity at the time of dropping changes, the thickness of the resin layer can be made uniform. However, in this manufacturing method, the thickness measurement of the resin layer in the extracted optical disc for inspection,
Also, regarding the optical disc manufactured while controlling the rotation speed based on the measured value, the thickness of the resin layer is still outside the specified value. Therefore, there is a problem that it is difficult to improve the yield during manufacturing. Even if the optical disc manufacturing line is stopped until the measurement of the resin layer thickness of the optical disc for inspection and the control of the rotation speed based on the measured value are completed, the optical disc manufacturing process that absorbs the measured value and after that The ambient temperature and humidity change during rotation speed control. In such a case, the rotation control based on the measured value does not make sense, and there is a problem that the film thickness cannot be made uniform.

On the other hand, a method is conceivable in which the rotation speed is controlled in real time so that the coating thickness becomes uniform while successively measuring the coating thickness of the coating liquid during spin coating. In this case, in this coating method, it is necessary to measure the coating thickness of the coating liquid with extremely high accuracy using a precision measuring device such as a laser displacement meter. However, when using such a precision measuring device, it is necessary to bring the precision measuring device and the object to be measured very close to each other, and it is necessary to measure the coating thickness using this measuring device while the optical disc is rotating. Is practically difficult.

The present invention has been made in view of the above problems, and provides a manufacturing method and a coating apparatus for a disk-shaped recording medium which can uniformly apply the coating liquid even if the state of the coating liquid changes. The main purpose is.

[0010]

In order to achieve the above object, a method of manufacturing a disk-shaped recording medium according to the present invention comprises a turntable on which a disk-shaped recording medium can be placed, and a central portion of the turntable is the center of the turntable. A disk-shaped member located at a central portion of the recording medium and mounted on the central portion of the recording medium, and rotating the turntable in a state where the recording medium and the disk-shaped member are mounted, and the disk-shaped member. Method for producing a disc-shaped recording medium, in which the coating liquid is spin-coated on the surface of the recording medium by a centrifugal force caused by the rotation of the turntable by dropping the coating liquid at a dropping position near the central portion on the upper surface of The turntable according to a time between a predetermined time point after the start of dropping of the coating solution and a time point when the coating solution reaches a first predetermined position defined in advance on the disk-shaped member. To control the rotation speed.

In this case, a plurality of control patterns for controlling the rotation speed of the turntable are defined in advance in correspondence with the time between the time points, and the control pattern corresponding to the time between the time points is It is preferable to select from a plurality of control patterns and control the rotation speed of the turntable according to the selected control pattern.

Further, it is preferable that each control pattern includes a constant speed rotation pattern for at least a predetermined time.

Further, it is preferable to complete the dropping of the coating liquid at the predetermined time point.

Further, it is preferable that the time point when the coating liquid reaches a second predetermined position defined in advance on the disk-shaped member is the predetermined time point.

Further, it is preferable to predefine the plurality of control patterns so that the rotational speed of the turntable at the constant speed rotation is controlled to be higher as the time between the two points is longer.

Further, at least from the predetermined time to the time when the coating liquid reaches the first predetermined position,
It is preferable to rotate the turntable at a constant speed.

Further, it is preferable to predefine the first predetermined position on the disk-shaped member.

Further, the coating apparatus of the present invention is a coating apparatus for spin-coating the coating liquid on the surface of the disk-shaped recording medium according to the method for manufacturing the disk-shaped recording medium according to claim 1, wherein the turntable comprises: A control unit that drives and controls a rotating motor, a sensor unit that is disposed above the first predetermined position and that detects the coating liquid that has reached the first predetermined position, and the disc-shaped member that has the coating unit. A coating liquid droplet lower portion for dropping the liquid, the control unit detects a time point when the coating liquid reaches the first predetermined position based on a detection signal of the sensor unit, and the predetermined time point, The rotation speed of the turntable is controlled according to the time between when the coating liquid reaches the first predetermined position.

Further, the coating apparatus of the present invention is a coating apparatus for spin-coating the coating liquid on the surface of the disk-shaped recording medium according to the method for manufacturing the disk-shaped recording medium according to any one of claims 2 to 8. A control unit for driving and controlling a motor for rotating the turntable; a storage unit for storing a plurality of control pattern data corresponding to the plurality of control patterns; and a storage unit disposed above the first predetermined position. And a lower part of the coating liquid drop that drops the coating liquid onto the disk-shaped member, and the control unit includes a detection signal of the sensor unit. The time when the coating liquid reaches the first predetermined position is detected based on the above, and when the predetermined time and the coating liquid are the first
The control pattern corresponding to the time between when the predetermined position is reached is selected from the storage unit and read out, and the rotation speed of the turntable is controlled according to the read control pattern.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a method for manufacturing a disk-shaped recording medium according to the present invention and a coating apparatus for manufacturing the disk-shaped recording medium according to the manufacturing method will be described below with reference to the accompanying drawings. To do.

First, the structure of the coating apparatus 1 will be described with reference to the drawings.

As shown in FIG. 1, the coating apparatus 1 includes a turntable 2, a vertical movement mechanism 3, a disk-shaped member 4, a motor 5,
Nozzle 6, resin supply unit 7, sensor 8, control unit 9, RAM
10 and ROM 11. In this case, the coating liquid R
Disk D, which is the target of application of
It is formed in a disk shape of about m, and at the center thereof, a mounting center hole having a diameter of about 15 mm for mounting the optical disc D in the recording / reproducing apparatus is formed. A recording area is formed on the outer peripheral portion of the mounting center hole in the optical disc D, and various data are recorded in the recording area in advance from the beginning of manufacture or afterwards. In addition, a width of 1 mm is provided between the recording layer and the mounting center hole.
A donut-shaped chucking area (unrecorded area) of about 0 mm is formed. On the other hand, turntable 2
As shown in FIG. 2, the disk-shaped base 2a has a flat upper surface on which an optical disc D can be mounted, and a shaft 2b connected to the center of the lower surface of the base 2a. The turntable 2 is not limited to having a flat upper surface, and a convex portion is formed along the circumferential direction on the innermost peripheral portion and the outermost peripheral portion, and the optical disc D is mounted on the convex portion. It is also possible to adopt a configuration in which the light incident surface side opposite to the recording area is prevented from being scratched due to contact by being placed. A motor 5 for rotating the turntable 2 is connected to the shaft 2b. The vertical movement mechanism 3 moves the disk-shaped member 4 and the sensor 8 onto the turntable 2 under the control of the control unit 9.

As shown in FIG. 2, the disk-shaped member 4 comprises a disk-shaped member main body 4a having a diameter of about 35 mm, and a shaft 4b erected at the center of the upper surface of the disk-shaped member main body 4a. When the coating liquid R is applied to the optical disc D, the coating liquid R is placed on the central portion of the upper surface of the optical disc D such that the central portion is located at the central portion of the turntable 2. In this case, it is preferable that the central parts of the three members are aligned. The disk-shaped member body 4a is, for example,
The lower surface in contact with the upper surface of the optical disc D is formed into a flat surface. However, the structure is not limited to this, and the disk-shaped member body 4a
It is also possible to adopt a configuration in which only the outer peripheral edge portion of the optical disc D contacts the upper surface of the optical disc D. In addition, the disk-shaped member body 4a,
Positioning (positioning) with the center of the turntable 2
A cylindrical convex portion 12 for the purpose is formed on the lower surface. Further, as will be described later, the disc-shaped member 4 is placed on the turntable 2 while the shaft 4b is held by the vertical movement mechanism 3, and in this state, the air below the disc-shaped member main body 4a is removed. The air is sucked toward the turntable 2 by being sucked by an air pump (not shown). Here, since the optical disc D is positioned by the protrusion that slightly protrudes toward the upper surface side of the center of the turntable 2, the optical disc D and the disc shape are positioned by the disc-shaped member 4 and the turntable 2. Positioning with the member 4 is completed at the same time. Since the structure for sucking the disk-shaped member 4 (the structure for the air pump and the suction) is known, its illustration and detailed description are omitted.

The motor 5 is drive-controlled by the controller 9 to rotate the turntable 2 at a predetermined rotation speed. The nozzle 6 discharges the coating liquid R supplied by the resin supply unit 7 onto the disk-shaped member 4 from its tip. This nozzle 6
Is moved up and down with respect to the disk-shaped member 4 by a vertical movement mechanism (not shown). The resin supply unit 7 constitutes the lower part of the coating liquid droplet in the present invention together with the nozzle 6, and supplies the coating liquid R to the nozzle 6 under the control of the control unit 9. In addition, the resin supply unit 7
Is provided with a liquid feed pump for feeding the coating liquid R from a coating liquid tank (not shown), and an electromagnetic valve that is opened and closed under the control of the control unit 9 (both not shown). The sensor 8 corresponds to the sensor unit in the present invention, and detects the arrival of the coating liquid R dropped on the disk-shaped member 4. The sensor 8 is composed of an infrared sensor and is arranged above the outer edge portion of the disc-shaped member 4 (a position corresponding to the upper side of the first predetermined position in the present invention), and by the vertical movement mechanism 3, the disc-shaped member 4 is provided. Moved up and down with 4. The control unit 9 drives and controls the vertical movement mechanism 3, the motor 5, and the resin supply unit 7. The RAM 10 corresponds to a storage unit in the present invention, and temporarily stores rotation control data of the motor 5 by the control unit 9 (data corresponding to control pattern data in the present invention) and calculation results of the control unit 9. The ROM 11 stores the operation program of the control unit 9.

Next, a method of applying the coating liquid R onto the optical disc D by the coating device 1 will be described with reference to the drawings.

First, as shown in FIG. 4, the optical disk D is positioned and suction-mounted on the turntable 2 with the coating surface of the coating liquid R facing upward. Next, the controller 9 drives the vertical movement mechanism 3 to move the disk-shaped member 4 downward,
As shown in FIG. 5, the lower surface of the disk-shaped member body 4a is brought into contact with the central portion of the optical disc D. At this time, the protrusion 12 of the disk-shaped member 4 is inserted into the mounting center hole of the optical disc D. Further, in this state, the disk-shaped member body 4a of the disk-shaped member 4 covers the mounting center hole and the chucking area of the optical disk D. Next, the control unit 9
The disk-shaped member 4 is driven by driving an air pump (not shown).
To the turntable 2 side.

Next, the control unit 9 drives and controls the motor 5 to rotate the turntable 2 at a constant rotation speed of, for example, about 25 rotations per minute, as shown in FIG.
Next, the control unit 9 moves the nozzle 6 downward and drives and controls the resin supply unit 7 to supply the coating liquid R to the nozzle 6. At this time, the tip of the nozzle 6 is arranged near the central portion of the disk-shaped member 4 (in the vicinity of the shaft 4b; a position corresponding to the dropping position in the present invention). By supplying the coating liquid R by the resin supply unit 7 in this state, the coating liquid R is dripped from the tip portion of the nozzle 6 to the vicinity of the central portion on the upper surface of the disk-shaped member 4, as shown in FIG. At this time, since the coating liquid R has a certain degree of viscosity, the coating liquid R is located in the vicinity of the shaft 4b on the disk-shaped member 4 immediately after being dropped from the nozzle 6. In this case, the control unit 9 starts the dropping of the coating liquid R (time t0 in FIG. 3) from
Until the completion of the dropping of the coating liquid R (time t1 in the figure), for example, 7
The coating liquid R is supplied from the resin supply unit 7 to the nozzle 6 over a time period of about 2 seconds.

On the other hand, the coating liquid R dropped on the disk-shaped member 4
7 flows out toward the outer edge of the disk-shaped member 4 due to the centrifugal force that accompanies the rotation of the turntable 2, as shown in FIG. At this time, the control unit 9 detects that the coating liquid R that has flown out has reached just below the sensor 8 based on the sensor signal output from the sensor 8. In this case, the coating liquid R is
The time required to reach directly below the sensor 8 (in the vicinity of the outer edge of the disk-shaped member 4) varies depending on the viscosity depending on the temperature and humidity at the time of dropping, within a range of about 2 to 3 seconds. Therefore, the control unit 9 completes the dropping of the coating liquid R (time t in FIG. 3).
From 1) to the time when the sensor signal of the sensor 8 is input (time t2, time t2a or time t2b in the figure), the rotation control data corresponding to the time is read from the RAM 10, and the rotation control data is read according to the rotation control data. At time t3, which is a predetermined time after the time t0, the rotation speed of the motor 5, that is, the rotation speed of the turntable 2 is controlled to increase.

Specifically, when the viscosity of the dropped coating liquid R is in a predetermined state or a state in which the viscosity is substantially similar, the control section 9 outputs the rotation control data corresponding to the time from time t1 to time t2. It is read from the RAM 10 and, as shown in FIG. 3, the maximum rotation speed of the turntable 2 is increased to the reference rotation speed, for example, 2000 rotations per minute, according to the rotation control data. On the other hand, when the viscosity of the dropped coating liquid R is relatively low and easily flows out, from the time when the dropping of the coating liquid R is completed (time t1) to the time when it reaches just below the sensor 8 (for example, time t2a in FIG. 3). The time is relatively short.
In this case, the control unit 9 selects and reads the rotation control data corresponding to the time from the time t1 to the time t2a from the RAM 10, and sets the maximum rotation speed of the turntable 2 as the reference rotation according to the rotation control data. The speed is increased to 1980 rpm which is slightly lower than the speed. On the contrary, when the viscosity of the dropped coating liquid R is relatively high and it is difficult for the liquid to flow out, from the time when the dropping of the coating liquid R is completed (time t1) to the time when it reaches just below the sensor 8 (for example, time t2b in the same figure). Will take a relatively long time. In this case, the control unit 9 selects and reads the rotation control data corresponding to the time from time t1 to time t2b from the RAM 10, and sets the maximum rotation speed of the turntable 2 as the reference rotation according to the rotation control data. The speed is increased to a speed slightly higher than the speed, for example, 2020 rpm. As described above, in the coating apparatus 1, the coating liquid R
The time from the completion of dropping of the ink to the time when it reaches just below the sensor 8 is measured. When the measurement time is short, the maximum rotation speed of the turntable is controlled to be slightly lower than the reference rotation speed, and when the measurement time is long. By controlling the maximum rotation speed of the turntable to be slightly higher than the reference rotation speed, the centrifugal force accompanying the rotation of the turntable 2 is finely adjusted. Therefore, even if the viscosity of the coating liquid R changes, the maximum rotation speed of the turntable 2 is controlled so that the way the coating liquid R spreads (moves on the disk-shaped member 4 and the optical disc D) becomes constant. To be done.

Next, the coating liquid R that has passed beneath the sensor 8
At the time when the rotation speed of the turntable 2 reaches the maximum rotation speed according to the rotation control data (time t4, time t in FIG. 3).
At 4a or time t4b), the outer edge of the disk-shaped member 4 is reached. After that, the coating liquid R that has reached the outer edge portion moves from the outer edge portion toward the upper surface of the optical disc, as shown in FIG. Next, as shown in FIG. 9, the coating liquid R that has flowed to the upper surface of the optical disc D moves along the upper surface toward the outer edge portion of the optical disc D. In this case, the coating liquid R moving on the upper surface of the optical disc D maintains the contour in a plan view shape in a circular shape, and the contour is rapidly expanded and stretched (stretched). Further, the excess coating liquid R reaching the outer edge of the optical disc D is scattered from the optical disc D by the centrifugal force applied to the optical disc D.

Subsequently, the control section 9 defines a predetermined time (predetermined time in the present invention: 6 seconds, for example, as a constant speed rotation pattern included as a part of the read rotation control data, in FIG. From time t4 to time t5), the motor 5 is rotated at a constant speed at the maximum rotation speed. Therefore, the specified time for rotating the turntable 2 at a constant speed is controlled according to the time from the completion of the dropping of the coating liquid R to the time when it reaches just below the sensor 8. Specifically, when the time from the completion of the dropping of the coating liquid R to the time immediately below the sensor 8 is short, that is, when the viscosity of the coating liquid R is low, the coating liquid when the resin supply unit 7 is constantly driven. The supply amount of R tends to be larger than the specified amount. Therefore, the control unit 9
According to the specified time for the constant speed rotation pattern included in the read rotation control data, a time slightly longer than the specified time for the constant speed rotation specified when the viscosity of the coating liquid R is a standard value (see FIG. At time t4a to time t5a), the turntable 2 is rotated at a constant speed. As a result, the unnecessary coating liquid R is surely scattered, and as shown in FIG. 10, a uniform layer of the coating liquid R is formed from the inner circumference to the outer circumference on the upper surface of the optical disc D. On the other hand, when the time from the completion of the dropping of the coating liquid R to the point of time immediately below the sensor 8 is long, that is, when the viscosity of the coating liquid R is high,
The supply amount of the coating liquid R when the resin supply unit 7 is steadily driven tends to be smaller than the specified amount. Therefore, at this time, the control unit 9 follows the specified time for the constant speed rotation pattern and is slightly shorter than the specified time for the constant speed rotation specified when the viscosity of the coating liquid R is the standard value (the same value). Turntable 2 at time t4b to time t5b in the figure)
Rotate at a constant speed. As a result, the coating liquid R is prevented from splashing more than necessary, and the coating liquid R is applied uniformly at the target coating thickness from the inner circumference to the outer circumference on the upper surface of the optical disc D.
Layers are formed.

Next, the control unit 9 expires the constant speed rotation time defined for each rotation control data (correctly, constant speed rotation pattern) (time t5, time t5a or time t5b in FIG. 3). Then, the turntable 2 is stopped by executing deceleration and stop control for the motor 5. Next, as shown in FIG. 11, the vertical movement mechanism 3 is drive-controlled to move the disk-shaped member 4 upward, and then the optical disk D on which the coating liquid R has been applied is removed from the coating apparatus 1. After that, by curing the coating liquid R by a predetermined curing treatment,
The resin layer (protective layer) is formed, and the optical disc D is completed.

As described above, according to the coating apparatus 1, the coating liquid R is dripped in the vicinity of the shaft 4b of the disk-shaped member 4 (dripping position in the present invention) and immediately below the sensor 8 (first in the present invention). When the time to reach the predetermined position) is short, that is, when the viscosity of the coating liquid R is low,
The turntable 2 is rotated at a speed lower than the reference rotation speed, and when the time from the time when the coating liquid R is dripped near the shaft 4b of the disk-shaped member 4 to the time immediately below the sensor 8 is long, that is, the coating is performed. When the viscosity of the liquid R is high, the turntable 2 is rotated at a speed higher than the reference rotational speed to control the centrifugal force exerted on the coating liquid R, so that even if the viscosity changes, a uniform target coating thickness can be obtained. The liquid R can be spin-coated. Therefore, the yield at the time of manufacturing the optical disc D can be improved. Further, according to the coating apparatus 1, unlike the method of controlling the rotation speed by measuring the thickness of the resin layer of the optical disc extracted for every predetermined number of sheets, for example, the optical disc D itself coated with the coating liquid R is Since the coating thickness can be controlled in real time, the yield at the time of manufacturing the optical disc D can be further improved.

Further, according to this coating apparatus 1, since the sensor 8 is arranged in the vicinity of the outer edge portion of the disk-shaped member 4,
For example, unlike the configuration in which the sensor 8 is disposed in the vicinity of the shaft 4b, the distance from the dropping position of the coating liquid R to directly below the sensor 8 (the first predetermined position in the present invention) can be defined to be relatively long. Therefore, when the coating liquid R flows out due to the centrifugal force caused by the rotation of the turntable 2, the time difference until it reaches right below the sensor 8 increases depending on the viscosity of the coating liquid R. As a result, the viscosity of the coating liquid R increases. The appropriate control can be executed. Further, according to the coating apparatus 1, by disposing the sensor 8 on the disc-shaped member 4, for example, unlike the configuration in which the sensor 8 is disposed above the optical disc D, the coating liquid R is the disc-shaped member. Since the control data can be read out by controlling the rotation speed of the turntable 2 at the stage of being positioned on the optical disc 4, the coating thickness can be made uniform over the entire area from the inner peripheral portion to the outer peripheral portion of the optical disc D. it can. Further, according to the coating device 1, the turntable 2 is rotated at a constant speed from the time when the dropping of the coating liquid R is completed to the time when it reaches the position right below the sensor 8, thereby changing the rotation speed of the turntable 2. Since it is possible to avoid variations in the flowing out of the coating liquid R, it is possible to obtain an accurate arrival time according to the viscosity, and as a result, it is possible to more accurately control the rotation speed of the turntable 2.

The present invention is not limited to the above-described embodiments of the invention, and can be modified as appropriate. For example, in the embodiment of the present invention, the example in which the sensor 8 is arranged in the vicinity of the outer edge portion of the disk-shaped member 4 has been described.
The predetermined position (position of the sensor portion) is not limited to this, and as shown in FIG. 12, a position closer to the central portion in the radial direction of the disk-shaped member 4 (position of the sensor 8a in the figure), disk-shaped. Position of outer edge of member 4 (disc-shaped member 4 and optical disc D
It may be defined in the boundary portion with the position, the position of the sensor 8b in the figure) or the position on the optical disc D (the position of the sensor 8c in the figure). In addition, in the embodiment of the present invention, the rotation speed of the turntable 2 is increased from the time t3 when a predetermined time has passed after the coating liquid R dropped on the disk-shaped member 4 has reached right below the sensor 8. Although an example has been described, for example, the rotation speed of the turntable 2 may be started to increase at the time when it is detected that the coating liquid R has reached just below the sensor 8. Furthermore, the time (acceleration) from the time when the rotation speed of the turntable 2 starts to increase to the time when the rotation speed specified by the rotation control data is reached can be appropriately changed and controlled.

Further, after the constant speed rotation control at the maximum rotation speed of the turntable 2 is completed (from the start time of the stop control)
The time (deceleration) until the turntable 2 is completely stopped is not limited to the example shown in the embodiment of the present invention. For example, even when the viscosity of the coating liquid R is different by controlling the deceleration in a shorter time as the completion time of the constant speed rotation control of the turntable 2 is delayed,
The time from the start of rotation of the turntable 2 to the stop thereof can be controlled to a fixed time. According to this control method, the time required for the coating process of the coating liquid R on one optical disc D can be always regulated to a constant value. The optical disc D can be smoothly transferred between them.

Further, in addition to the sensor 8, the sensor 8a shown in FIG. 12 is arranged above the second predetermined position on the disk-shaped member body 4a, and when the sensor 8a detects the arrival of the coating liquid R. From the (predetermined time), the sensor 8 applies the coating liquid R
It is also possible to select a control pattern in accordance with the time until the arrival of is reached and to control the rotation speed of the turntable 2 in accordance with the selected control pattern. According to this configuration, the rotation speed of the turntable 2 can be controlled more accurately according to how the coating liquid R flows out, that is, the viscosity of the coating liquid R. The target film thickness can be made uniform. Further, in the embodiment of the present invention, the time between the predetermined time point after the start of the dropping of the coating solution R and the time point when the coating solution R reaches the first predetermined position previously defined on the disk-shaped member 4. As an example of controlling the rotation speed of the turntable 2 according to the above, an example of controlling according to the rotation control data (control pattern) has been described, but the present invention is not limited to this. For example, at a predetermined time after the start of dropping the coating liquid R,
The coating liquid R is placed on the disk-shaped member 4 at a predetermined first predetermined position.
It is also possible to calculate the rotation speed of the turntable 2 according to a predetermined mathematical expression based on the time between when the rotation speed reaches and the rotation speed of the turntable 2 is controlled according to the calculation result. However, when the method of controlling according to the rotation control data is adopted, the time required for the control can be shortened because the calculation is not necessary, so that the optical disc D (disc-shaped recording medium) coated with the coating liquid R can be used. The coating thickness can be reliably controlled in real time.

[0038]

As described above, according to the method for manufacturing a disk-shaped recording medium of the present invention, the predetermined time point after the start of the dropping of the coating liquid and the first predetermined position defined in advance on the disk-shaped member. By controlling the rotation speed of the turntable according to the time between the time when the coating liquid reaches and the rotation speed of the turntable is measured, for example, the coating thickness of the disk-shaped recording medium on which the coating liquid has been applied is measured. Unlike the manufacturing method that controls the speed, since the coating thickness of the disk-shaped recording medium on which the coating liquid is applied can be controlled in real time, the yield can be improved, resulting in the manufacturing cost of the disk-shaped recording medium. Can be sufficiently reduced. Moreover, since the structure can be simply configured without using a precision measuring device, the manufacturing cost of the disc-shaped recording medium can be further reduced.

Further, according to the disc-shaped recording medium manufacturing method of the present invention, a plurality of control patterns for controlling the rotation speed of the turntable are defined in advance, and the predetermined time point after the start of the dropping of the coating liquid is set. , The control pattern corresponding to the time between the time when the coating liquid reaches the first predetermined position defined in advance on the disk-shaped member or the disk-shaped recording medium is selected from the plurality of control patterns, and is selected. By controlling the rotation speed of the turntable according to the control pattern, the coating thickness of the disc-shaped recording medium to which the coating liquid is applied can be reliably controlled in real time, so that the yield can be improved. It is possible to sufficiently reduce the manufacturing cost of the recording medium.

Further, according to the method for manufacturing the disk-shaped recording medium of the present invention, by including the constant speed rotation pattern of at least the predetermined time in each control pattern, the expansion and contraction control of the predetermined time allows the coating. The coating liquid can be spin-coated so that the target coating thickness is uniform even if the viscosity of the liquid changes. Therefore, the yield at the time of manufacturing the disc-shaped recording medium can be sufficiently improved.

Further, according to the method for manufacturing the disk-shaped recording medium of the present invention, the rotation speed of the turntable is controlled with the completion of the dropping of the coating liquid as a predetermined time point, whereby the first coating liquid is formed.
It is possible to clearly specify the starting time when measuring the time required to reach the predetermined position.

Further, according to the method for manufacturing the disc-shaped recording medium of the present invention, the rotation speed of the turntable is defined as a predetermined time when the coating liquid reaches the second predetermined position defined on the disc-shaped member. The rotation speed of the turntable can be controlled more accurately in accordance with the viscosity of the coating liquid by controlling the above, so that the coating film of the coating liquid can be made more uniform.

Further, according to the method for manufacturing a disc-shaped recording medium of the present invention, a plurality of rotational speeds of the turntable during the constant speed rotation are controlled to be higher as the time between both time points is longer. By predefining the control pattern, the centrifugal force exerted on the coating liquid can be controlled, so that the coating liquid can be spin-coated so as to obtain a uniform coating thickness even if the viscosity changes, resulting in a disk shape. The yield at the time of manufacturing the recording medium can be further improved.

Further, according to the method for manufacturing a disk-shaped recording medium of the present invention, the coating liquid is first applied from at least a predetermined time point.
Since the turntable is rotated at a constant speed until it reaches the predetermined position of, it is possible to avoid variations in the flowing out of the coating liquid due to fluctuations in the rotation speed of the turntable. As a result, the rotation speed of the turntable can be controlled more accurately.

Further, according to the method for manufacturing a disc-shaped recording medium of the present invention, the first predetermined position is defined in advance on the disc-shaped member, so that, for example, the first disc is formed on the disc-shaped recording medium.
Different from the configuration for defining the predetermined position, the coating thickness can be made uniform over the entire area from the inner peripheral portion to the outer peripheral portion of the disk-shaped recording medium.

Further, according to the coating apparatus of the present invention, the control unit detects the time when the coating liquid reaches the first predetermined position based on the detection signal of the sensor unit, and detects the predetermined time and the coating liquid. By controlling the rotation speed of the turntable according to the time between when the disk reaches the first predetermined position, the coating thickness of the disk-shaped recording medium to which the coating liquid is applied can be controlled in real time. As a result, the yield can be improved, and as a result, the manufacturing cost of the disk-shaped recording medium can be sufficiently reduced. Moreover, since the structure can be simply configured without using a precision measuring device, the manufacturing cost of the disc-shaped recording medium can be further reduced.

Further, according to the coating apparatus of the present invention,
The control unit detects the time when the coating liquid reaches the first predetermined position based on the detection signal of the sensor unit, and the time between the predetermined time and the time when the coating liquid reaches the first predetermined position. The control pattern corresponding to the above is selected and read from the storage unit, and the rotation speed of the turntable is controlled according to the read control pattern, so that the coating thickness of the disk-shaped recording medium to which the coating liquid is applied can be reliably controlled in real time. Therefore, the yield can be improved, and as a result, the manufacturing cost of the disk-shaped recording medium can be sufficiently reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a coating device 1 according to an embodiment of the present invention.

FIG. 2 is a side sectional view of a turntable 2 and a disk-shaped member 4 and a side view of a sensor 8 on which an optical disc D is placed.

FIG. 3 is a control pattern diagram showing an example of rotation speed control of the turntable 2 by the coating device 1.

FIG. 4 is a side sectional view showing a state in which an optical disc D is placed on the turntable 2.

5 is a side sectional view of the disk-shaped member 4 placed on the optical disc D in the state of FIG.

6 is a shaft 4 of the disk-shaped member 4 in the state of FIG.
It is a side surface sectional view of the state where the coating liquid R was dropped near b.

FIG. 7 shows that the coating liquid R in the state of FIG.
It is a side sectional view in a state where it has expanded to just below.

8 is a side sectional view showing a state in which the coating liquid R in the state of FIG. 7 has flowed out onto the optical disc D. FIG.

9 is a side sectional view showing a state in which the coating liquid R in the state of FIG. 8 has spread to the outer edge of the optical disc D. FIG.

10 is a side cross-sectional view showing a state where the optical disc D in the state of FIG. 9 is temporarily rotated at a maximum rotation speed at a constant speed.

FIG. 11 is a side sectional view when the application of the coating liquid R is completed.

FIG. 12 is a side sectional view of the turntable 2 and the disk-shaped member 4, and a side view of the sensors 8a to 8b whose arrangement positions are changed.

[Explanation of symbols]

1 coating device 2 turntable 3 Vertical movement mechanism 4 Disc-shaped member 5 motor 6 nozzles 7 Resin supply section 8, 8a-8c sensor 9 control unit 10 RAM 11 ROM D optical disc R coating liquid

Claims (10)

[Claims] 1. A turntable on which a disc-shaped recording medium can be placed, and a disc-shaped member whose central portion is located at the central portion of the turntable and which is placed on the central portion of the recording medium. The turntable is rotated with the recording medium and the disk-shaped member placed, and the coating liquid is dropped at a dropping position near the central portion on the upper surface of the disk-shaped member, whereby the dropped coating is performed. A method for manufacturing a disc-shaped recording medium, wherein a liquid is spin-coated on the surface of the recording medium by a centrifugal force caused by the rotation of the turntable, wherein a predetermined time point after the start of the dropping of the coating liquid and the disc-shaped member. A method for manufacturing a disk-shaped recording medium, wherein the rotation speed of the turntable is controlled according to the time between when the coating liquid reaches the first predetermined position defined in advance. 2. A plurality of control patterns for controlling the rotation speed of the turntable corresponding to the time between the two time points are defined in advance, and the plurality of control patterns corresponding to the time between the two time points are defined. 2. The method for manufacturing a disc-shaped recording medium according to claim 1, wherein the rotation speed of the turntable is controlled according to the selected control pattern. 3. The method for manufacturing a disk-shaped recording medium according to claim 2, wherein a constant speed rotation pattern for at least a predetermined time is included in each of the control patterns. 4. The method for manufacturing a disk-shaped recording medium according to claim 1, wherein the completion of dropping of the coating liquid is the predetermined time. 5. The disk-shaped recording medium according to claim 1, wherein the time when the coating liquid reaches a second predetermined position defined in advance on the disk-shaped member is the predetermined time. Production method. 6. The plurality of control patterns are defined in advance so that the rotational speed of the turntable during the constant speed rotation is controlled to be higher as the time between the two points is longer. A method for manufacturing a disc-shaped recording medium according to any one of 1. 7. The disk according to claim 1, wherein the turntable is rotated at a constant speed at least from the predetermined time to the time when the coating liquid reaches the first predetermined position. Recording medium manufacturing method. 8. The method for manufacturing a disc-shaped recording medium according to claim 1, wherein the first predetermined position is defined in advance on the disc-shaped member. 9. A coating device for spin-coating the coating liquid on the surface of the disk-shaped recording medium according to the method for manufacturing a disk-shaped recording medium according to claim 1, wherein a motor for rotating the turntable is driven and controlled. A control unit, a sensor unit that is disposed above the first predetermined position and detects the coating liquid that has reached the first predetermined position, and a coating liquid droplet that drops the coating liquid onto the disk-shaped member. The control unit detects a time point when the coating liquid reaches the first predetermined position based on a detection signal of the sensor unit, and the predetermined time point and the coating liquid is the first time. The coating device for controlling the rotation speed of the turntable according to the time between when the predetermined position is reached. 10. A coating device for spin-coating the coating liquid onto the surface of the disk-shaped recording medium according to the method for manufacturing the disk-shaped recording medium according to claim 2, wherein the turntable is rotated. A control unit for driving and controlling the motor, a storage unit for storing a plurality of control pattern data respectively corresponding to the plurality of control patterns, and a first predetermined position provided above the first predetermined position. A sensor unit for detecting the coating liquid that has reached, and a coating liquid droplet lower portion for dropping the coating liquid onto the disk-shaped member, wherein the control unit is the first unit based on a detection signal of the sensor unit. A time point when the coating liquid reaches a predetermined position is detected, and the control pattern corresponding to the time between the predetermined time point and the time point when the coating liquid reaches the first predetermined position is stored in the storage unit. Select and read And, coating apparatus for controlling the rotational speed of the turntable in accordance with the read control pattern.