JP2003272257A - Spin coat apparatus for producing optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spin coat apparatus for producing an optical disk in which defective delivery due to blocking of a nozzle tip part can be prevented even on the occurrence of an operation stop for a long period of time and the continuous productivity of forming a pigment recording layer can stably be maintained. <P>SOLUTION: In the spin coat apparatus employing: a transparent resin disk substrate 1 having a center hole; a spindle 2 holding horizontally the center hole of the substrate 1 and fixed; and a nozzle 3 for dropping a pigment solution from the upper part of the substrate 1 to the substrate 1 the dropped pigment solution is spread uniformly on the surface of the substrate 1 by rotation of the spindle 2 to form a pigment recording layer. The apparatus is additionally provided with an automatic replacement function whereby after the apparatus is stopped for a prescribed time, a prescribed amount of the pigment solution is jetted from the nozzle 3 to replace the pigment solution at the nozzle tip with new pigment solution. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a spin coater used for producing an optical disc. 2. Description of the Related Art Conventionally, a recording layer of an optical disk has been formed by:
The spin coating method is used because it is easy and has excellent productivity. Typical optical disks produced using the spin coating method include a CD-R type optical disk having a structure in which a dye recording layer, a reflective layer, and a protective layer are laminated in this order on a disk-shaped transparent resin substrate. A DVD-R type structure having a structure in which a laminate comprising a dye recording layer, a reflective layer, and a protective layer and a disc-shaped transparent resin substrate are adhered on a disc-shaped transparent resin substrate with an adhesive such that the recording layer is on the inside. There is an optical disk. FIG. 2 is a schematic view showing the structure of a spin coating apparatus generally used conventionally. In the spin coating method, the substrate 1 is rotated at a low speed by the motor 4 and the dye solution is dropped on the surface of the substrate 1 by the nozzle 3. afterwards,
The substrate is rotated at a high speed by a motor 4 and the dropped dye solution is diffused and dried thinly by centrifugal force to form a dye recording layer on the substrate. Incidentally, in the optical disk formed by the spin coating method, since the film thickness and the film thickness distribution after the formation of the recording layer affect the recording characteristics of the disk, the desired film thickness and the reproducibility of the film thickness distribution during continuous production are not obtained. It is required and it is important to suppress the film thickness variation between disks during continuous production. [0005] The conventional spin coater as shown in FIG. 2 has to be stopped due to, for example, a failure in a production line or the like, or a systematic supply such as replenishment of a dye solution. If the spin coater is stopped for a relatively long time from the state of continuous operation and then restarted as in the operation, the nozzle tip is blocked by drying of the dye solution, and the dye solution is removed. This makes it difficult to smoothly drop the liquid from the nozzles, which hinders the formation of a recording layer having a desired film thickness and film thickness distribution. In addition, even if the nozzle is not closed, the liquid solution pool that slightly protrudes from the nozzle tip dries and gradually precipitates.
accumulate. As a result, the deposit fell on the film during the formation of the recording layer, causing defects in the recording layer. Conventionally, such problems have been dealt with by temporarily stopping the apparatus and replacing the nozzle body with a new one. There were problems that it could not be completely prevented and that the production efficiency was further reduced. SUMMARY OF THE INVENTION It is an object of the present invention to completely prevent a discharge failure due to blockage of a nozzle tip portion and to stably maintain the continuous productivity of forming a dye recording layer, regardless of a long-time operation stoppage. It is to provide a spin coater for optical disk production that can perform the above. [0007] In order to solve the above-mentioned problems, the present invention provides a disk-shaped transparent resin substrate having a center hole, a spindle having a center hole portion of the substrate held horizontally and fixed. A spin coating apparatus for forming a dye recording layer by uniformly spreading the dropped dye solution on the surface of the substrate by rotating a spindle with a nozzle for dropping the dye solution onto the substrate from above the substrate; After the completion of the dropping of the dye solution from the substrate, after the apparatus is stopped for a predetermined time or more, a predetermined amount of the dye solution is discharged from the nozzle,
A spin coating apparatus for producing an optical disk, which has an automatic replacement function of replacing a dye solution at a nozzle tip with a new one. [0008] As described above, if the apparatus is stopped for a predetermined time or more and the standby state continues after the discharge of the dye solution from the nozzle to the substrate and the formation of the recording layer are completed, the nozzle is restarted when the apparatus is restarted. Since a predetermined amount of the dye solution is preferably discharged only once and the dye solution at the nozzle tip is replaced with a new one, it is possible to reliably prevent the dye solution from being blocked at the nozzle tip by drying. That is,
For example, if the spin coater has been forced to stop for some reason, such as a production line failure,
Even if the apparatus is stopped for a relatively long time from a state of continuous operation, such as a scheduled work such as a replenishment of a dye solution, it is possible to prevent a discharge failure due to blockage of a nozzle tip portion, The formation of the recording layer having the desired film thickness can be reliably restarted. This makes it possible to provide a spin coater capable of stably maintaining the continuous productivity of forming the recording layer. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a spin coater according to the present invention. A disk-shaped transparent resin substrate 1 having a center hole fixed to a spindle 2 in FIG. 1 is rotated at a low speed by a motor 4. Then, a predetermined amount of the dye solution is dropped from the nozzle 3 onto the surface of the substrate 1. Thereafter, the substrate 1 is rotated at a high speed by the motor 4, and the dropped dye solution is diffused and dried by centrifugal force to form a dye recording layer on the substrate 1. Here, if the spin coater has to be stopped for some reason (for example, maintenance due to a failure of the production line, etc.), or the scheduled operation such as replenishment of the dye solution is continued. If you shut down for a relatively long period of time after it was running,
The timer 7 measures the stop time of the apparatus. When the stop time exceeds a predetermined time, when the device is started again, the replacement function of the present invention is automatically operated,
A predetermined amount of the dye solution is discharged only once from the nozzle, and the dye solution at the nozzle tip is replaced with a new one. Thereby, the blockage of the nozzle tip is removed, and the dye solution is smoothly dropped on the surface of the substrate 1 by the nozzle 3,
By the rotation of the motor 4, a recording layer having a desired film thickness is formed on the substrate 1. Next, a method of producing an optical disk by using the spin coater having the automatic replacement function as described above will be described. As an optical disc, a CD-R type optical disc having a structure in which a dye recording layer, a reflective layer, and a protective layer are laminated in this order on a disc-shaped transparent resin substrate, and a dye recording layer, a reflection layer, There is a DVD-R type optical disk having a structure in which a laminate composed of a protective layer and a disc-shaped transparent resin substrate are bonded together with an adhesive such that the recording layer is on the inside. As a substrate material, for example, acrylic resin,
There are plastics such as polycarbonate resin and polyethylene resin, glass, and the like. Particularly preferred substrates include injection-molded polycarbonate resin substrates from the viewpoints of wet heat resistance, mass productivity, and price. Note that a tracking groove is formed in a spiral shape on the substrate. The material of the dye recording layer is not particularly limited as long as it absorbs a recording laser beam and converts it into heat, and general examples include cyanine dyes, phthalocyanine dyes, and the like. Organic dyes such as an azo dye, a pyromethene dye, a porphyrin dye, and an azaporphyrin dye are exemplified. As the solvent for the dye solution for forming the dye recording layer, various known solvents can be used. The solvent is not particularly limited as long as it does not attack the substrate surface. For example, ethylcyclohexane, 1,2- Dimethylcyclohexane,
Methylcyclohexane, octane and the like can be mentioned. Au, Ag, C
Metals such as u and Al are used, and these reflective layers are usually formed by a sputtering method. Also, as the protective layer,
Although not particularly limited, an acrylic ultraviolet curable resin is preferable in consideration of durability and versatility in mass production. Examples of the present invention and comparative examples will be described below. (Embodiment) FIG. 1 is a schematic view of a spin coating apparatus according to an embodiment of the present invention, in which a spindle 2 in which a center hole of a disc-shaped transparent resin substrate 1 having a center hole is horizontally held and fixed.
A motor 4 for rotating the substrate 1 placed on the spindle 2, a discharge pump 5 and a nozzle 3 for dropping a dye solution from above the substrate 1 onto the substrate 1, and a discharge control mechanism 6 for controlling the same. It comprises a timer 7 for measuring the stop time of the device. As the dye solution used for forming the recording layer, a solution obtained by dissolving a phthalocyanine dye in 1,2-dimethylcyclohexane was used. Next, the operation of the present embodiment will be described.
First, when the substrate 1 having the center hole mounted and fixed on the spindle 2 is rotated at a low speed by the motor 4, the discharge pump 5 is rotated.
By the operation described above, a predetermined amount of the dye solution is dropped onto the substrate 1 from the nozzle 3. Next, the substrate 1 mounted and fixed on the spindle 2 is rotated at high speed by the motor 4, and the dye solution dropped on the substrate 1 is diffused and dried on the surface of the substrate 1 by centrifugal force, and the entire surface of the substrate 1 is dried. When the dye recording layer is formed, the rotation of the motor 3 is stopped. The substrate 1 on which the recording layer is formed is taken out by a transport mechanism (not shown) and transported to the next step. Next, when the next substrate is placed on the spindle 2 by another transport mechanism (not shown) from the previous process, the rotation of the spindle 2 and the dropping of the dye solution from the nozzle are performed in the same manner as described above.
A recording layer is formed on the entire surface of the substrate 1, and the substrate 1 is taken out again by the transport mechanism and transported to the next step. In this way, the formation of the dye recording layer on the surface of the substrate 1 is continuously repeated. Here, the spin coater has been continuously operated, for example, suddenly stopped due to some cause (for example, maintenance due to failure or the like) or planned work such as replenishment of the dye solution. When the apparatus is stopped from the state for a relatively long time, the apparatus enters a standby state from the previous process until the next substrate is transported, and at the same time, the timer 7 is operated to start measuring the stop time of the apparatus. Then, when the measured stop time of the spin coating apparatus has passed a predetermined time, a signal for operating the replacement function is transmitted to the ejection control mechanism 6, and this signal is stored until the apparatus is restarted. Will be retained. The predetermined time set in advance is a time longer than the production tact time. Then, the spin coater is restarted,
When the next substrate is placed on the spindle 2 again by the transport mechanism from the previous process, the discharge control mechanism 6 sends the next substrate to the discharge pump 5.
The discharge pump 5 receives a signal from the discharge control mechanism 6 to activate the replacement function, and discharges a predetermined amount of the dye solution from the nozzle 3 only once based on the signal. However, the predetermined amount discharged from the nozzle 3 is such that the dye solution remaining at the tip of the nozzle is completely replaced with a new one. As a result, the dye solution at the tip of the nozzle is replaced with a new one, and the blockage at the tip of the nozzle can be reliably removed and prevented. Therefore, the ejection of the substrate 1 mounted on the spindle 2 can be prevented without causing a discharge failure. The formation of a dye recording layer having a desired film thickness on the surface can be restarted. Comparative Example A recording layer was continuously formed in the same manner except that a conventional spin coater having no automatic replacement function of the present invention was used. That is, even if the apparatus was stopped for some reason and the tip of the nozzle was closed, the recording layer of the optical disk was continuously formed without removing it. In each of the examples and comparative examples, the thickness of the recording layer formed continuously was measured by measuring the absorbance with an inspection device attached to the apparatus, and the change was monitored. When 1,000 dye recording layers of an optical disk were continuously produced according to the comparative example, the film thickness of the recording layers fluctuated greatly, and the production could not be maintained stably. On the other hand, when 1,000 dye recording layers are continuously produced according to the embodiment, the fluctuation of the film thickness of the recording layer in the continuous production can be suppressed, and the formation of the recording layer of the optical disc having a desired film thickness can be stably maintained. I was able to. According to the present invention, the spin coater is continuously stopped as in a case where the spin coater has to be stopped for some reason or a planned operation such as replenishment of a dye solution. Even if the apparatus is stopped for a relatively long time from the operation state, it is possible to prevent the ejection failure due to the blockage of the nozzle tip, so that the formation of the dye recording layer having the desired film thickness can be reliably restarted. Can be done. Thereby, the continuous productivity of forming the recording layer can be stably maintained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a spin coater according to an embodiment of the present invention. FIG. 2 is a schematic view showing a conventional spin coater. [Description of Signs] 1 Disc-shaped transparent resin substrate 2 Spindle 3 Nozzle 4 Motor 5 Discharge pump 6 Discharge control mechanism 7 Timer

Claims (1)

Claims: 1. A disc-shaped transparent resin substrate having a center hole,
A spindle that horizontally holds and fixes the center hole of the substrate, and a nozzle for dropping the dye solution onto the substrate from above the substrate, uniformly apply the dropped dye solution to the surface of the substrate by rotating the spindle. In a spin coater to form a dye recording layer by spreading the dye solution after completion of the dropping of the dye solution from the nozzle to the substrate, after stopping the device for a predetermined time or more, discharge a predetermined amount of the dye solution from the nozzle,
A spin coater for producing optical disks, having an automatic replacement function for replacing a dye solution at a nozzle tip with a new one.