JP3449848B2 - Apparatus and method for forming light transmitting layer in optical disc - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for forming a light transmitting layer in a novel optical disc. More specifically, the present invention relates to a technique for accurately forming a light transmission layer that covers a signal surface of an optical disc in a short time.

[0002]

2. Description of the Related Art FIG. 1 shows the structure of an optical disc 1.

Pits (representing a signal by unevenness) 3 are formed on one surface of a transparent substrate 2 formed of a transparent synthetic resin, for example, a polycarbonate resin,
A surface (hereinafter referred to as "signal surface") 4 on which the pits 3 are formed is covered with a reflective film 5 made of aluminum or the like. The reflective film 5 is covered with a transparent protective light transmission layer 6.

Then, the optical pickup is adapted to receive the laser light emitted from the optical pickup and reflected by the reflection film 5 to read the pits 3.

[0005]

Conventionally, signal reading by an optical pickup is performed by irradiating laser light from the substrate 2 side (see FIG. 2).

By the way, with the increase in recording density of optical discs, the influence of substrate warpage cannot be ignored. The influence of the warp of the medium in which the laser light advances can be made smaller as the thickness of the medium becomes thinner, but normally the thickness of the substrate 2 is about 1.2 mm, and it is not possible to make it as thin as about 0.6 mm. It is possible, but it is technically difficult to make it thinner.

Therefore, it is conceivable to irradiate the laser beam from the side of the light transmitting layer 6 formed so as to cover the signal surface 4 (see FIG. 3). Conventionally, the surface of the light transmitting layer 6 is uniform. In addition, there is a possibility that accurate signal reading and / or writing cannot be performed.

Therefore, an object of the present invention is to make it possible to form a light transmitting layer that covers a signal surface of an optical disc with high precision and in a short time.

[0009]

In order to solve the above-mentioned problems, an apparatus for forming a light-transmitting layer in an optical disc of the present invention comprises a substrate rotating means for rotating a substrate and a signal of the substrate rotated by the substrate rotating means. Ultraviolet curable resin supply means for dropping liquid ultraviolet curable resin near the center of the surface and supplying it in a ring shape, and irradiating ultraviolet rays to the ultraviolet curable resin distributed so as to cover the signal surface by centrifugal force due to rotation of the substrate. and a UV supply means for curing, ultraviolet supply hand
The step irradiates the ultraviolet spot light and the ultraviolet spot
Light is moved from the center side of the substrate to the outer peripheral side.
Further, the method for forming a light transmitting layer in the optical disc of the present invention comprises a step of dropping a liquid ultraviolet curable resin near the center of the signal surface of the substrate while rotating the substrate and supplying it in a ring shape,
Rotating the substrate to which the ultraviolet curable resin is supplied in an annular shape near the center of the signal surface and diffusing the ultraviolet curable resin entirely from the center side to the outer peripheral side by the centrifugal force due to the rotation, and from the center side to the outer peripheral side the ultraviolet diffused ultraviolet curing resin on the entire irradiated have a curing the ultraviolet curing resin to a predetermined thickness, ultraviolet light of the ultraviolet curable resin
The process of firing was diffused from the center side to the outer side
Substrate spinning UV spot light on UV curable resin
While moving from the center side to the outer side of the
The cured resin is cured from the center side to the outer side in order to a specified thickness.
It is something that goes .

Therefore, according to the present invention, the substrate is rotated, and the liquid ultraviolet curing resin, which is annularly supplied near the center by the centrifugal force, is diffused so as to cover the entire signal surface,
Since it is irradiated with ultraviolet rays to cure it to a predetermined thickness,
The light transmission layer covering the signal surface can be formed with high precision, that is, without unevenness on the surface and with a uniform film thickness, and in a short time.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an apparatus and method for forming a light transmitting layer in an optical disc of the present invention will be described below with reference to the accompanying drawings. In the following description, the light transmission layer 6 in the read-only optical disc 1 is formed.

Device 7 for forming a light transmitting layer in an optical disk
Has a motor 9 supported on the machine base 8, and the output shaft 9 of the motor 9
a extends upward. A substrate mounting table 10 is fixed to the upper end of the motor output shaft 9a, and the substrate 2 is supported on the upper surface of the substrate mounting table 10 with the signal surface 4 facing upward. The motor 9, the output shaft 9a, and the substrate mounting table 10 constitute a substrate rotating means.

An ultraviolet curable resin supplier 12 having a resin supply nozzle 11 as an ultraviolet curable resin supply means for supplying liquid ultraviolet curable resin onto the signal surface 4 of the substrate 2 is provided above the machine base 8. There is. The resin supply nozzle 1
1 is positioned so as to point to a position slightly deviated from the rotation center of the substrate mounting table 10.

Further, as an ultraviolet ray supplying means for irradiating the ultraviolet ray spot light to the liquid ultraviolet ray curable resin supplied so as to cover the signal surface 4 of the substrate 2 supported on the substrate mounting table 10 above the machine table 8. A UV irradiator 14 having a UV nozzle 13 is arranged. Then, the UV irradiator 14 moves from a position where the UV nozzle 13 is directed near the center of the substrate 2 supported on the substrate mounting table 10 to a position where it is directed outside the outer periphery of the substrate 2. Has been made possible.

A method of forming the light transmission layer 6 covering the signal surface 4 of the substrate 2 by using the light transmission layer forming device 7 of the optical disk will be described below.

First, the substrate 2 is placed on the substrate platform 10 with the signal surface 4 facing up (see FIG. 5). Then, the resin supply nozzle 11 is positioned so as to direct the boundary portion 15 between the inner peripheral edge of the reflective film 5 and the central portion of the substrate. When the ultraviolet curable resin supply device 12 is fixedly provided, the resin supply nozzle 11 directs the boundary portion 15 when the substrate 2 is mounted on the substrate mounting table 10. It will be.

Next, the motor 9 is driven to drive the substrate mounting table 1
0, that is, while rotating the substrate 2 at a low speed, the ultraviolet curable resin 16 is dropped from the resin supply nozzle 11 to supply the ultraviolet curable resin 16 in an annular shape on the boundary portion 15 (see FIG. 6).

Then, the substrate 2 is rotated at a high speed and a centrifugal force is applied to the ultraviolet curable resin 16 supplied in the above annular shape, so that the ultraviolet curable resin 16 goes from the central portion to the outer peripheral portion in the entire area of the signal surface 4. It is diffused so as to extend (see FIG. 7).

Then, the UV irradiator 14 is moved to move U
The V nozzle 13 is directed toward the inner peripheral edge of the ultraviolet curable resin 16 diffused so as to cover the entire signal surface 4, and the ultraviolet spot light 1 is emitted from the UV nozzle 13 while rotating the substrate 2.
7 is irradiated to cure the ultraviolet curable resin 16. That is,
The UV curable resin 16 is layered by moving the UV nozzle 13 from the inner peripheral side to the outer peripheral side of the ultraviolet curable resin 16.
Is sequentially cured from the inner peripheral side to the outer peripheral side (see FIG. 8). At this time, the ultraviolet curable resin 16 is cured in a state where the layer has a predetermined thickness. For this purpose, if the film to be cured next is thin,
The rotation speed of the substrate 2 is reduced to weaken the centrifugal force acting,
On the contrary, if the film thickness is thick, it is advisable to cure the substrate 2 from the point where the film thickness appears, while controlling the rotation speed of the substrate 2 to increase the centrifugal force that acts.

As described above, by appropriately selecting various conditions such as the amount of the ultraviolet curable resin 16 to be dropped, the rotation speed of the substrate 2, etc., the signal surface 4 can be covered thinly (0.1 to 0.2 m).
m) and the light transmitting layer 6 having a uniform film thickness over the entire surface can be efficiently formed.

In the above-mentioned embodiment, the ultraviolet curing resin is irradiated with ultraviolet spot light from the inner peripheral side to the outer peripheral side. However, this is not a spot type one. Alternatively, for example, the entire surface of the ultraviolet curable resin may be irradiated with ultraviolet rays using a surface irradiation type ultraviolet irradiation device.

In the above example, the read-only optical disc 1 is used.
Although the case where the light transmission layer is formed in the above is described, it is needless to say that the present invention can be applied to the formation of the light transmission layer of a readable / writable optical disc.

[0023]

As is apparent from the above description, the apparatus for forming the light transmitting layer in the optical disc of the present invention is
Substrate rotating means for rotating the substrate, ultraviolet curable resin supply means for dripping liquid ultraviolet curable resin in the vicinity of the center of the signal surface of the substrate being rotated by the substrate rotating means and supplying it in an annular shape, and centrifugal force due to rotation of the substrate and a UV supply means for curing by irradiating ultraviolet rays to the ultraviolet curing resin is distributed to cover the signal surface by UV supply means
Irradiating the ultraviolet spot light and the ultraviolet spot light
Is moved from the center side of the substrate to the outer peripheral side, and the method for forming the light transmitting layer in the optical disc of the present invention is
While rotating the substrate, a step of dropping a liquid ultraviolet curable resin near the center of the signal surface and supplying the liquid in an annular shape, and rotating the substrate on which the ultraviolet curable resin is annularly supplied near the center of the signal surface, The process of diffusing the UV curable resin entirely from the center side to the outer peripheral side by the centrifugal force due to rotation, and irradiating the UV curable resin diffused from the center side to the outer peripheral side with ultraviolet rays to a predetermined thickness. possess and curing, the irradiation with ultraviolet rays to the ultraviolet curing resin
Ultraviolet light diffused throughout the process from the center side to the outer side
The center of the substrate rotating the UV spot light on the cured resin
UV curing resin by irradiating while moving from the side to the outer side
Is sequentially hardened to a predetermined thickness from the center side to the outer peripheral side .

Therefore, according to the present invention, the substrate is rotated, and the liquid ultraviolet curable resin which is circularly supplied near the center by the centrifugal force is diffused so as to cover the entire signal surface,
Since it is irradiated with ultraviolet rays to cure it to a predetermined thickness,
The light transmission layer covering the signal surface can be formed with high precision, that is, without unevenness on the surface and with a uniform film thickness, and in a short time.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of an optical disc with the thickness of each portion emphasized.

FIG. 2 is a diagram showing one method of signal reading.

FIG. 3 is a diagram showing another signal reading method.

FIG. 4 is a vertical sectional side view showing an outline of a light transmission layer forming apparatus.

FIG. 5 is a schematic view showing a method of forming a light transmitting layer in an optical disc according to the present invention, together with FIGS. 6 to 8, and showing a state in which a substrate is placed on a substrate placing table.

FIG. 6 shows a step of annularly supplying an ultraviolet curable resin onto a substrate.

FIG. 7 shows a step of diffusing an ultraviolet curable resin over the entire signal surface.

FIG. 8 shows a step of irradiating the ultraviolet curable resin diffused over the entire signal surface with an ultraviolet spot light.

[Explanation of reference numerals] 1 optical disk 2 substrate 4 signal surface 6 light transmission layer 7 light transmission layer forming device 9 motor (substrate rotation means) 9a output shaft (substrate rotation means) 10 substrate mounting table (substrate rotation means) 12 ultraviolet curable resin Supply machine (UV curable resin supply means) 14 UV irradiation machine (UV supply means) 16 Liquid UV curable resin 17 UV spot light

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-56-13534 (JP, A) JP-A-7-14217 (JP, A) JP-A-9-161334 (JP, A) JP-A-62- 41006 (JP, A) JP-A-4-283434 (JP, A) JP-A-3-173954 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 7/26

Claims (2)

(57) [Claims] 1. A device for forming a light-transmitting layer covering a surface of a substrate on which a signal is formed (hereinafter, referred to as “signal surface”), the substrate rotating means rotating the substrate, and the substrate rotating means. Ultraviolet curing resin supply means that drips liquid ultraviolet curing resin near the center of the signal surface of the rotating substrate and supplies it in an annular shape, and ultraviolet curing that is distributed so as to cover the signal surface by the centrifugal force due to the rotation of the substrate. and a UV supply means for curing the ultraviolet resin is irradiated, the ultraviolet supply means when irradiated with ultraviolet spot light co
Move the ultraviolet spot light from the center side of the substrate to the outer peripheral side
An apparatus for forming a light-transmitting layer in an optical disc, which is characterized in that: 2. A light transmitting layer is formed to cover the signal surface of the substrate.
The method is to rotate liquid crystal near the center of the signal plane while rotating the substrate.
The step of dropping the external-curing resin and supplying it in a ring shape, and the ultraviolet-curing resin was supplied in a ring shape near the center of the signal surface.
The substrate is rotated, and the centrifugal force generated by the rotation causes ultraviolet light.
Process to diffuse the cured resin from the center side to the outer periphery side
And UV curable resin diffused throughout from the center side to the outer side
UV light is applied to the resin to cure the UV curable resin to a specified thickness.
The step of irradiating the above ultraviolet curable resin with ultraviolet rays has a step of
To the UV curable resin that has been diffused all the way from the
Line spot light is rotating from the center of the rotating substrate to the outer periphery
Irradiate while moving to remove the UV curable resin from the center side.
It is intended to go by sequentially cured to a predetermined thickness to the peripheral side
And a method for forming a light-transmitting layer in an optical disc.