JP2008165914A - Manufacturing method of optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical disk which can form film a light transmission layer with a uniform thickness on an entire surface of an optical disk. <P>SOLUTION: The manufacturing method of the optical disk is used for manufacturing the optical disk D which is formed by sequentially laminating a recording layer 4 and a light transmission layer 6 on a substrate 2 for at least either recording or reproduction an information signal by light incoming from the light transmission layer 6 side. This method comprises steps of; spreading the ultraviolet curing resin on the surface of the recording layer 4 by dropping a liquefied ultraviolet curing resin on the recording layer 4 of the substrate 2 while rotating the substrate 2 around the center of the substrate 2; forming the light transmission layer 6 by curing the spread ultraviolet curing resin, and controlling at least either of a rotation state of the substrate 2 or a temperature distribution state on the substrate 2 according to the result of measurement while measuring the film thickness of the ultraviolet curing film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present application relates to a method of manufacturing an optical disc such as a DVD (Digital Versatile Disc) and a BD (Blue-Ray Disc).

  In recent years, an optical disk such as a DVD exists as a kind of data storage medium. The optical disc is, for example, formed by sequentially laminating a recording layer and a light transmission layer on a substrate, and at least one of recording and reproduction of an information signal is performed by light incident from the light transmission layer side. The light transmission layer is formed by forming a cured film on the surface of a substrate on which a recording layer is formed using an ultraviolet curable resin.

  The light transmission layer is manufactured by, for example, a spin coating method, a film transfer method, a sheet method, or the like. As an example, in the spin coating method, a liquid resin is dropped on the surface of the base material while rotating the base material, so that the entire surface of the base material is uniformly stretched by the centrifugal force of rotation. By extending, a cured film is formed over the entire surface of one side of the substrate (for example, Patent Document 1 or 2).

JP 2003-33713 A JP 2003-233936 A

  However, in the conventional spin coating method, it is difficult to maintain uniformity over the entire surface of the disk due to various circumstances such as changes in the viscosity of the ultraviolet curable resin depending on the manufacturing environment, and the like. The film thickness tends to be non-uniform. For this reason, an optical aberration occurs during recording / reproduction, and there is a problem that information signals cannot be reproduced or recorded stably.

  Therefore, in order to solve an example of such a problem, an object of the present application is to provide a method of manufacturing an optical disc capable of forming the light transmission layer uniformly over the entire surface of the optical disc.

  In order to solve the above-described problem, an optical disk manufacturing method according to claim 1 of the present invention is formed by sequentially laminating a recording layer (4) and a light transmission layer (6) on a substrate (2), and the light transmission A method of manufacturing an optical disc (D) in which at least one of recording and reproduction of an information signal is performed by light incident from a layer side, wherein a liquid ultraviolet curable resin is dropped on the recording layer of the substrate, A step of diffusing the ultraviolet curable resin on the surface of the recording layer while rotating the substrate around a rotation axis; and a step of forming the light transmission layer by curing the diffused ultraviolet curable resin. And a control step of controlling at least one of the rotation state of the substrate or the temperature distribution state on the substrate according to the measurement result while measuring the film thickness of the ultraviolet curable resin. Have And wherein the door.

  The optical disk manufacturing method according to claim 2 of the present invention is such that a recording layer and a light transmission layer are sequentially laminated on a substrate, and information signals are recorded and reproduced by light incident from the light transmission layer side. A method of manufacturing an optical disc in which at least one of them is performed, wherein a liquid ultraviolet curable resin is dropped on a recording layer of the substrate, and the substrate is rotated with the center of the substrate as a rotation axis. A step of diffusing to the surface of the layer, a step of curing the diffused ultraviolet curable resin to form the light transmissive layer, and a step of measuring the film thickness of the ultraviolet curable resin in the process of forming the light transmissive layer. And at least one of a rotation state of the substrate, a dripping state of the ultraviolet curable resin, or a temperature distribution state on the substrate according to the measurement result of the film thickness measured previously. Characterized in that further comprises a control step of controlling One.

  Hereinafter, the best embodiment of the present application will be described with reference to the accompanying drawings.

  First, an optical disk manufactured by the optical disk manufacturing method of the present application will be described with reference to FIG.

  As shown in FIG. 1, the optical disc D has an annular substrate 2 having a hole 2a in the center. The substrate 2 is made of resin material such as acrylic resin, polycarbonate (PC) resin, polyolefin resin, or glass. It is made of materials. On one surface of the substrate 2, pits or grooves asperities 2 b corresponding to information signals are formed by injection molding, and the surface on which the pits or grooves are formed is a recording surface. On the recording surface, for example, a recording layer 4 made of any one of an rewritable optical recording layer, a write once optical recording layer, and a phase change optical recording layer is provided.

  Further, the light transmission layer 6 is formed on the surface of the recording layer 4 by, for example, spin coating. In the light transmission layer 6, an ultraviolet curable resin is formed on the entire surface of the optical disk D with a uniform film thickness.

  The optical disc D formed by sequentially laminating the recording layer 4 and the light transmission layer 6 on the substrate 2 performs at least one of recording and reproduction of information signals by light incident from the light transmission layer 6 side. It has come to be. In addition, since the optical transmission layer 6 is formed with a uniform film thickness over the entire surface of the substrate 2, the optical disc D can stably reproduce or reproduce an information signal during recording and reproduction. Recording is possible.

  Next, an optical disk manufacturing apparatus for forming a light transmission layer will be described with reference to FIG.

  The optical disk manufacturing apparatus S of the present embodiment rotates the substrate 2 on which the recording layer 4 is formed, and drops a liquid resin made of an ultraviolet curable resin onto the surface of the substrate 2 to form a cured film made of the light transmission layer 6. This is an apparatus for forming a uniform film thickness over the entire surface of the optical disk D.

  As shown in FIG. 2, the optical disc manufacturing apparatus S includes a stage 11 on which a substrate 2 on which a recording layer 4 is formed, a rotating mechanism unit 14 that rotates the stage 11, and UV curing on the substrate 2. A resin dripping part 16 for dripping resin, a resin heating part 18 for heating the ultraviolet curable resin, a resin curing part 20 for curing the ultraviolet curable resin, and a film thickness of the light transmission layer formed by the ultraviolet curable resin. And a film thickness measuring unit 25 that measures the above. Each unit 14, 16, 18, 20, 25 is controlled by the system control unit 30.

  The stage 11 is formed in a substantially circular shape, and a projection formed in substantially the same shape as the inner diameter of the substrate 2 is provided at the center thereof. The protrusion is provided with a fixing means for fixing the substrate 2, and the substrate 2 is detachably fixed.

  The rotation mechanism unit 14 includes a spindle motor for rotating the stage, and is connected to the stage 11 via a bearing (not shown). The rotation mechanism unit 14 is managed by the system control unit 30 and controls the rotation speed of the spindle motor by controlling the rotation speed of the spindle motor. Thereby, the rotation state of the substrate 2 can be controlled.

  The resin dripping unit 16 includes a tank for storing an ultraviolet curable resin (not shown), a supply nozzle 16a for guiding the ultraviolet curable resin to a specified position on the substrate, and a predetermined amount of the ultraviolet curable resin from the tank (not shown) to the supply nozzle 16a. And a supply amount adjusting means to be supplied. The resin dropping unit 16 is managed by the system control unit 30 and controls the supply amount adjusting means to control the dropping amount of the ultraviolet curable resin dropped onto the substrate 2 from the supply nozzle 16a. Yes. Thereby, the dripping state of the ultraviolet curable resin can be controlled.

  The resin heating unit 18 includes, for example, an IR heater 18 a that irradiates far infrared rays, and is disposed above the substrate 2.

  The resin curing unit 20 includes a UV lamp 20 a that irradiates ultraviolet rays, and is disposed above the substrate 2.

  Although not shown, the IR heater 18a or the UV lamp 20a includes an irradiating unit that irradiates far infrared rays or ultraviolet rays having a predetermined light amount and an adjusting unit that adjusts the light amount. Further, the IR heater 18a or the UV lamp 20a has a plurality of types such as a type that irradiates a predetermined amount of light to a partial region of the substrate 2, and a type that irradiates the entire radial direction of the substrate or the entire substrate. Is appropriately selected according to the application and used.

  The IR heater 18a of the present embodiment uses a type that irradiates far infrared rays to a partial region in the radial direction of the substrate 2 and moves the IR heater main body from the inside to the outside of the substrate 2. The apparatus further includes means. The IR heater 18a is managed by the system control unit 30, and irradiates the substrate 2 with far infrared rays with a predetermined amount of light while moving the IR heater body from the inside to the outside of the substrate 2, thereby It is possible to irradiate far-infrared rays over the entire radial direction. Thus, the substrate can be heated to a predetermined temperature separately for each predetermined region, and the temperature distribution state on the substrate 2 can be managed (controlled). In addition, by heating the substrate 2, the fluidity of the ultraviolet curable resin dropped on the substrate 2 can be increased.

  Further, the UV lamp 20a of the present embodiment further includes a moving means for moving the UV lamp main body in the vertical direction of the substrate 2. The UV lamp 20 a is managed by the system control unit 30, and the irradiation area to the substrate 2 can be changed by irradiating the substrate 2 with ultraviolet rays while moving the UV lamp main body closer to or away from the substrate 2. It is possible. Further, by changing the ultraviolet irradiation region and irradiating the ultraviolet curable resin with ultraviolet rays separately for each predetermined region, the ultraviolet curable resin can be cured for each region. The temperature distribution state can also be managed (controlled).

  As described above, the IR heater 18a and the UV lamp 20a are managed by the system control unit 30, and the position and amount of light of the IR heater 18a or the UV lamp 20a are controlled. The infrared irradiation range and irradiation amount are controlled.

  The film thickness measurement unit 25 includes, for example, sensors 25 a to 25 c including an irradiation unit that irradiates a substrate with infrared light and a light receiving unit that receives infrared light reflected from the substrate. The film thickness of the light transmission layer 6 is measured by reading the difference between the reflection of the surface of the film and the reflection of the sputter surface below it.

  The sensors 25a to 25c are provided to measure the film thickness of the light transmission layer 6 at a plurality of arbitrary points in the radial direction of the substrate 2, for example, in the radial direction of the substrate 2 as shown in FIG. Are provided above the inner peripheral region, the central region, and the outer peripheral region, respectively. And each sensor 25a-25c is managed by the system control part 30, and each is started, Each film | membrane of the light transmissive layer 6 corresponding to three area | regions of an inner peripheral area | region, a center area | region, and an outer peripheral area | region by each sensor 25a-25c. The thickness is measured.

  The sensor 25a-25c is provided with a moving means for moving the sensor 25 in the radial direction of the substrate 2, and one sensor is controlled at a predetermined speed to move from the inside to the outside. The film thickness of the layer 6 may be measured.

  The system control unit 30 includes a central processing unit (CPU) having a calculation function, a working RAM, and a ROM that stores various data and programs. The CPU executes various programs stored in the ROM, for example, thereby controlling each part and overall controlling the entire optical disc manufacturing apparatus S.

  Based on the film thickness measured by each of the sensors 25a to 25c of the film thickness measurement unit 25, the system control unit 30 determines the light amount, position, and position of the IR heater and UV lamp so as to obtain a uniform film thickness over the entire surface of the optical disc D. Parameters that determine the operating speed and operating time, parameters that determine the amount of UV-curing resin dripped onto the substrate 2 and timing of dropping, parameters that determine the rotational speed, operating time, and operating timing of the spindle motor are optimal. It corrects to a value and controls each part 14, 16, 18, 20, 25 using the correction value.

  Specifically, in this embodiment, the system control unit 30 adjusts the supply amount of the ultraviolet curable resin dripped onto the substrate 2 while controlling the rotation of the stage 11 with a predetermined value, and the IR heater. Of the light-transmitting layer 6 formed of an ultraviolet curable resin by sequentially driving the sensors 25a to 25c provided from the radially inner peripheral region to the outer peripheral region of the substrate 2. Measure the film thickness. Then, based on the film thickness state of the light transmission layer 6, the values of the respective parameters are corrected so that the film thickness of the light transmission layer 6 is uniform over the entire optical disk, and each part is used using the correction value. 14, 16, 18, 20, 25 are controlled.

  The optical disk D formed in this way measures the film thickness of the light transmission layer 6, corrects the value of each parameter according to the measurement result, and uses the correction value to each of the parts 14, 16, 18, 20 25, the thickness of the light transmission layer 6 can be uniformly formed over the entire surface of the optical disc D, and the quality depends on the room temperature of the manufacturing work place and the viscosity of the resin. The quality can be made uniform without any problems.

  Next, an example of forming a light transmission layer on an optical disc using an optical disc manufacturing apparatus will be described.

<Example 1>
In the first embodiment, parameters for controlling the respective units 14, 16, 18, 20, 25 are defined in advance, and the respective units 14, 16, 18, 20, 25 are controlled based on the parameters to control the optical disc D. When the light transmission layer 6 is formed, the thickness of the light transmission layer 6 is measured in the formation process of the light transmission layer 6, and the light transmission layer 6 is applied to the entire surface of the substrate 2 based on the measurement result. The above parameters are corrected so as to obtain a uniform film thickness, and the optical disk D is manufactured by controlling the respective parts 14, 16, 18, 20, and 25 according to the corrected values.

  First, in FIG. 2, the system control unit 30 defines in advance a state in which the substrate 2 on which the recording layer 4 having a concavo-convex portion is formed is attached to the stage 11 with the film formation surface facing upward. While the spindle motor is driven at the rotated speed (low speed) and the substrate 2 is rotated, the dropping amount of the liquid UV curable resin dropped on the recording surface by the resin dropping portion 16, the light amount of the IR heater, and the irradiation of infrared rays Control the time. Thereby, a liquid ultraviolet curable resin is dropped on the recording layer 4 of the substrate 2, and the ultraviolet curable resin is diffused on the surface of the recording layer 4 by the centrifugal force generated by the rotation of the substrate 2.

  Next, the system control unit 30 drives the motor at a predetermined number of rotations (high speed), and further diffuses the ultraviolet curable resin to the outside of the substrate 2, while the sensors 25 a to 25 c of the film thickness measurement unit 25. Is controlled to start measuring the film thickness of the light transmission layer 6. Specifically, the film thickness of the light transmission layer 6 is measured in the order of the inner peripheral region, the central region, and the outer peripheral region of the substrate 2 by the sensors 25a to 25c.

  Next, based on the measurement result, the system control unit 30 sets the parameters for controlling the units 14, 16, 18, 20, and 25 to the optimum correction values so as to make the film thickness of the light transmission layer 6 uniform. The portions 14, 16, 18, 20, and 25 are controlled by the correction values, the diffused ultraviolet curable resin is cured to form the light transmission layer 6, and the process is terminated.

  Specifically, first, the film thickness of the light transmission layer 6 in the inner peripheral region of the substrate 2 is measured, and when the film thickness reaches a predetermined reference value, the inner peripheral region is irradiated with ultraviolet rays by a UV lamp, and ultraviolet curing is performed. The resin is cured. Thereby, even if the substrate 2 continues to rotate, the ultraviolet curable resin does not flow outward, so that the light transmission film 6 in the inner peripheral region maintains the film thickness when the ultraviolet curable resin is cured. Similarly, by forming the light transmission layer 6 in the order of the central region and the outer region, it becomes possible to make the film thickness uniform over the entire surface of the optical disc D.

  As described above, instead of correcting the parameters as appropriate when manufacturing the optical disc D for each sheet, a predetermined number of lots is defined in advance, and the parameters are corrected for each number of lots. It doesn't matter.

<Example 2>
While the first embodiment corrects the parameters for controlling the units 14, 16, 18, 20, and 25 to appropriate parameters for each optical disc D when the light transmission layer is formed, the second embodiment Then, after measuring the film thickness distribution of the light transmission layer 6 in the formation process of the light transmission layer 6 and manufacturing the optical disc D using parameters specified in advance, the measurement result of the film thickness distribution of the light transmission layer 6 Based on the above, the parameter is corrected to an optimum value so that the light transmission layer 6 has a uniform film thickness over the entire surface of the substrate 2, and the respective parts 14, 16, 18, 20, 25 are changed according to the corrected value. The subsequent optical disc D is manufactured under control.

  First, in FIG. 2, the system control unit 30 defines in advance a state in which the substrate 2 on which the recording layer 4 having a concavo-convex portion is formed is attached to the stage 11 with the film formation surface facing upward. While the spindle motor is driven at the rotated speed (low speed) and the substrate 2 is rotated, the dropping amount of the liquid UV curable resin dropped on the recording surface by the resin dropping portion 16, the light amount of the IR heater, and the irradiation of infrared rays Control the time. Thereby, a liquid ultraviolet curable resin is dropped on the recording layer of the substrate 2, and the ultraviolet curable resin is diffused on the surface of the recording layer 4 by the centrifugal force generated by the rotation of the substrate 2.

  Next, the system control unit 30 drives the motor at a predetermined number of rotations (high speed), and further diffuses the ultraviolet curable resin to the outside of the substrate 2, while the sensors 25 a to 25 c of the film thickness measurement unit 25. Is controlled to start measuring the film thickness of the light transmission layer 6. Specifically, the film thickness of the light transmission layer 6 is measured in the order of the inner peripheral region, the central region, and the outer peripheral region of the substrate 2 by the sensors 25a to 25c.

  Next, the system control unit 30 controls the UV lamp to cure the ultraviolet curable resin diffused on the substrate 2 to form the light transmission layer 6.

  Next, the system control unit 30 is configured to make each film thickness of the light transmission layer 6 uniform over the entire substrate 2 based on the measurement results of the film thickness of the light transmission layer 6 by the sensors 25a to 25c. The parameters for controlling 14, 16, 18, 20, and 25 are corrected to optimum correction values, and the process is terminated. In the subsequent optical disk D, the light transmission layer 6 is formed by controlling the respective parts 14, 16, 18, 20, 25 with the optimum correction value.

  In addition, this embodiment is one form and is not limited to this form. For example, in the present embodiment, the film thickness measuring unit 25 measures three points on the inside, the center, and the outside of the substrate 2 by the sensors 25a to 25c. If many film thicknesses in the radial direction 2 are measured, it is possible to increase the accuracy with which the film thickness can be controlled uniformly. In addition, the components may be appropriately combined and integrated, or may be changed to a commonly used component.

It is sectional drawing which shows the optical disk manufactured by the optical disk manufacturing method of this application. It is a figure which shows the schematic structural example of an optical disk manufacturing apparatus.

Explanation of symbols

D Optical disk 2 Substrate 4 Recording layer 6 Light transmission layer

Claims (3)

A method of manufacturing an optical disc, wherein a recording layer and a light transmission layer are sequentially laminated on a substrate, and at least one of recording and reproduction of an information signal is performed by light incident from the light transmission layer side,
Dropping a liquid ultraviolet curable resin on the recording layer of the substrate and diffusing the ultraviolet curable resin on the surface of the recording layer while rotating the substrate around the center of the substrate;
Curing the diffused ultraviolet curable resin to form the light transmission layer;
Comprising
The method further includes a control step of controlling at least one of the rotation state of the substrate or the temperature distribution state on the substrate according to the measurement result while measuring the film thickness of the ultraviolet curable resin. An optical disc manufacturing method. A method of manufacturing an optical disc, wherein a recording layer and a light transmission layer are sequentially laminated on a substrate, and at least one of recording and reproduction of an information signal is performed by light incident from the light transmission layer side,
Dropping a liquid ultraviolet curable resin on the recording layer of the substrate and diffusing the ultraviolet curable resin on the surface of the recording layer while rotating the substrate around the center of the substrate;
Curing the diffused ultraviolet curable resin to form the light transmission layer;
Measuring the film thickness of the ultraviolet curable resin in the process of forming the light transmission layer;
Comprising
The method further includes a control step of controlling at least one of the rotation state of the substrate, the dripping state of the ultraviolet curable resin, or the temperature distribution state on the substrate according to the measurement result of the film thickness measured previously. A method of manufacturing an optical disc, wherein   3. The method of manufacturing an optical disk according to claim 1, wherein the measurement of the film thickness is at least three points out of an inner peripheral area, a central area, and an outer peripheral area of the substrate.

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