JPH02184801A - Method for reproducing grating - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a grating replication method.

2. Description of the Related Art Conventionally, as a method for duplicating a grating on the surface of an optical information recording medium such as an optical disk, for example, Japanese Patent Application Laid-open No. 1987-
There is one disclosed in the 116105% publication. Taking an optical disk as an example, a method of duplicating a grating using the well-known 2P method will be described with reference to FIGS. 3 to 5. First, a stamper (mold) 3 is fixed on a support plate 2 placed under the U-shaped arm 1, and an ultraviolet curing resin 4 is poured onto the surface of the stamper 3. On the other hand, the acrylic plate 7 is vacuum chucked at the peripheral end of the holder 6 fixed to the upper cylinder 5, and air is inserted between the holder 6 and the acrylic plate 7 to make the acrylic plate 7 into a convex shape. . Then, as shown in FIG. 4, in this state, the acrylic plate 7 is lowered and pressed from above the ultraviolet curing resin 4 to bring the acrylic plate 7 and stamper 3 into close contact, and then the holder 6 is removed. With the acrylic plate 7 and the stamper 3 in close contact with each other in this manner, the acrylic plate 7 is exposed to ultraviolet (UV) light and cured, and then the stamper 3 is peeled off to form a desired optical disc (not shown). Can be duplicated.

Problems to be Solved by the Invention When producing a high-density, deep-groove grating using the 2P method as described above, there are several problems as shown below. First, the ultraviolet curable resin 4 is poured into the stamper 3 with high density and deep grooves, and when it is cured by ultraviolet irradiation in this state, it becomes extremely adhesive, making it difficult to peel off the acrylic plate 7 even if you try to peel it off. It becomes difficult.

As a result, unless the adhesion between the acrylic plate 7 and the ultraviolet curing resin 4 is stronger than the adhesion between the stamper 3 and the ultraviolet curing resin 4, the acrylic plate 7 and the ultraviolet curing resin 4 will not peel off at the time of peeling. The problem arises that it cannot be reproduced. In order to solve this problem, it is possible to use an adhesive (not shown) in order to further strengthen the adhesion between the acrylic plate 7 and the ultraviolet curing resin 4; Adding additional work leads to an increase in the number of steps, resulting in extremely poor production efficiency.

Another problem is that when trying to use the polarization separation characteristics of the replicated grating, that is, when trying to use transmitted light (0th order light) and diffracted light (1st order light), the acrylic plate 7. If the film thickness of the ultraviolet curing resin 4, adhesive, etc. becomes uneven, or if gaps or dust appear at the boundaries, the diffraction angle will change, resulting in a decrease in light utilization efficiency. This causes a decrease in diffraction efficiency.

Means for Solving the Problem Therefore, in order to solve such problems, claim 1
In the described invention, a multifunctional ultraviolet curable resin is poured into a mold fixed to a rotary table in the resin coating process, and the rotary table is rotated in the exposure process and UV exposure is performed at the same time as the rotation or after the rotation is completed. The multifunctional ultraviolet curable resin is gelled or completely cured, and in the groove forming step, the resin coating step and the exposure step are repeated multiple times until a thickness equal to or greater than the desired groove depth is obtained. forming the outermost surface of the polyfunctional ultraviolet curable resin into a gel state, and using a monofunctional ultraviolet curable resin on the outermost surface of the polyfunctional ultraviolet curable resin that has been made into a gel state in the thick film forming step; The exposure step was repeated a plurality of times to duplicate a grating of a desired thickness, and the duplicated grating was peeled off from the mold in a peeling step.

Further, in the invention according to claim 2, the monofunctional ultraviolet curing resin is poured into a mold fixed to a rotary table in the resin coating step, and the rotary table is rotated in the exposure step, and the rotation is completed simultaneously or at the same time as the rotation. Afterwards, the 1-functional ultraviolet curable resin is exposed to ultraviolet light to make it gel-like or completely cured, and in the groove and thick film forming step, the resin coating step and the exposure step are repeated multiple times to obtain the desired groove depth and thickness. The grating formed with the desired thickness was replicated, and the replicated grating was peeled off from the mold in a peeling process.

According to the invention described in claim 1, by peeling from the mold and replicating the grating using only the polyfunctional ultraviolet curable resin and the monofunctional ultraviolet curable resin, it is possible to replace the conventional acrylic plate and ultraviolet curable resin. It is possible to eliminate the peeling phenomenon that occurred during the process. Further, according to the invention as claimed in claim 2, by peeling from the mold and replicating the grating using only the monofunctional ultraviolet curable resin, it is possible to eliminate the problem that occurs between the conventional acrylic plate and the ultraviolet curable resin. Peeling phenomenon can be eliminated.

Embodiment First, an embodiment of the invention as claimed in claim 1 is shown in FIGS. 1 and 2.
This will be explained based on the diagram.

The method for duplicating the grating is shown in step a in Figure 1.
-g will be explained separately. First, in the resin coating step a, a stamper 9 as a mold is fixed on a spinner 8 as a rotating table, and a bifunctional ultraviolet curable resin 10 as a multifunctional ultraviolet curable resin is poured onto the surface of the stamper 9. .

Next, in exposure steps step c, the spinner 8 coated with the bifunctional ultraviolet curing resin 10 is rotated on the stamper 9. Then, at the same time as this rotation or after the rotation is completed, ultraviolet ray exposure is performed, and the bifunctional ultraviolet curing resin 10
gelatinize or completely harden.

Next, in groove forming steps d and e, application of the bifunctional ultraviolet curing resin 10 and exposure to ultraviolet light are repeated multiple times until a desired thickness equal to or greater than the depth of the grooves P of the grating 11 is obtained.

Here, the reason why the application is stopped when the desired depth of the groove P is obtained is that when a polyfunctional resin such as a bifunctional resin is used as the ultraviolet curing resin, the molecular chain of the resulting polymer is It has a bridging structure and is very strongly bonded, making it hard, but on the other hand, it is susceptible to warping and cracking, and as a result, there is a high possibility that it will break when peeled off. Therefore, in order to avoid such a phenomenon, when the thickness of the grating 11 is equal to or greater than the depth of the grooves P,
The coating with the bifunctional ultraviolet curing resin 10 is discontinued. In this case, after repeating such a coating process multiple times, the outermost surface of the bifunctional ultraviolet curable resin 10 is gelled only in the final coating process so that the following treatment can be performed. put.

Next, in the thick film forming step, the same processing as in the groove forming steps d and e is performed. That is, here, coating and exposing the monofunctional cured resin 12 to the surface of the gelled bifunctional cured resin 1o are repeated several times, and finally, sufficient ultraviolet light exposure is performed to completely cure the gelled bifunctional cured resin 1o. Let it harden. As a result, a grating 11 having a desired thickness that is resistant to warpage and cracking is created. In this case, since the adhesion between the monofunctional ultraviolet curing resin 12 and the bifunctional ultraviolet curing resin 10 is performed on the gelled surface, copolymerization occurs on the adhesion surface, increasing the bonding strength. It becomes strong, and
Since the monofunctional ultraviolet curable resin 12 has a linear structure, it is extremely resistant to cracking against warping.

Thereby, the grating 11 with desired grooves and film thickness can be replicated.

Finally, in peeling steps f and g, the surface of the duplicated grating 11 is vacuum chucked and peeled off, thereby obtaining a duplicated product.

As described above, by performing each of steps a to g using the bifunctional ultraviolet curable resin 10 and the monofunctional ultraviolet curable resin 12 formed on the surface, a grating with desired grooves and film thickness is formed. 11 can be easily reproduced, thereby eliminating the need to worry about the peelability between the acrylic plate 7 and the ultraviolet curing resin 4 as in the past. Quality gratings can be reproduced. Moreover, since unevenness in film thickness can be suppressed as much as possible, it is possible to eliminate phenomena such as changes in the diffraction angle and decreases in light utilization efficiency and diffraction efficiency, which are conventional.

In this example, the bifunctional ultraviolet curable resin 10 was used as the polyfunctional ultraviolet curable resin, but it is of course possible to use trifunctional or higher functional resins. In addition, in steps d and e, the number of times it is repeated is:
It can be determined by calculation from the desired thickness setting value of the duplicate product and the film thickness obtained in one operation.

Next, an embodiment of the invention according to claim 2 will be described. In this example, polyfunctionality was not used in the ultraviolet curing resin.
This is an example in which only the functional ultraviolet curing resin 12 is used. Therefore, in this case, all the resins to be applied, exposed and cured in steps a-g are monofunctional ultraviolet curing resin 1
2, and as in the above-mentioned embodiments, it is possible to obtain a grating 11 that is resistant to warping and has high reliability and is resistant to unevenness in film thickness. By using only the monofunctional cured resin 12 in this manner, the grating 11 can be replicated with a simpler process than in the embodiments described above.

Incidentally, the working steps of these two embodiments are shown in a flowchart as shown in FIG. 2. In this case, in step C, when creating the monofunctional ultraviolet curable resin 12 from the polyfunctional (bifunctional) ultraviolet curable resin 10 as in the invention described in claim 1, the route is gelled. Follow the steps on the right.

Effects of the Invention In the invention described in claim 1, by replicating a grating using a multifunctional ultraviolet curable resin and a monofunctional ultraviolet curable resin, a grating with desired grooves and film thickness can be easily reproduced. As a result, there is no need to worry about the peelability between the acrylic plate and the ultraviolet curable resin as in the past, and it is possible to reproduce reliable, high-quality gratings that are less likely to have uneven film thickness. be. Moreover, since unevenness in film thickness can be suppressed as much as possible, it is possible to eliminate phenomena such as changes in the diffraction angle and decreases in light utilization efficiency and diffraction efficiency, which are conventional.

Further, in the invention according to claim 2, by replicating the grating using only a monofunctional ultraviolet curable resin, it is possible to further simplify the work process and perform processing compared to the invention according to claim 1.

In addition, in this case as well, it is possible to reproduce a highly reliable, high-quality grating that is less likely to cause film thickness unevenness, and because it is possible to suppress film thickness unevenness as much as possible, the diffraction angle does not change as in conventional methods. It is possible to eliminate phenomena such as a decrease in light utilization efficiency and diffraction efficiency.

[Brief explanation of the drawing]

1(a) to (g) are process diagrams showing a grating duplication process, FIG. 2 is a flowchart thereof, FIGS. 3 and 4 are explanatory diagrams showing a duplication method using a conventional grating duplication apparatus, and FIG. FIG. 5 is an explanatory view showing how the resin is cured on the stamper side by the exposure. 8... Turntable, 9... Mold, 10... Multi(2) functional ultraviolet curing resin, 1-1... Grating, 1
2... monofunctional ultraviolet curing resin, a... resin coating process, b, c... exposure process, d, e... groove forming process (
Thick film creation process) f. G...Peeling process, P...Groove L Go 1 four enemies...J, Z diagram

Claims (1)

[Claims] 1. In the resin coating process, a polyfunctional ultraviolet curable resin is poured into a mold fixed on a rotary table, and in the exposure process, the rotary table is rotated and ultraviolet rays are applied at the same time or after the rotation. Exposure is performed to make the multifunctional ultraviolet curable resin gel-like or completely cured, and in the groove forming step, the resin coating step and the exposure step are repeated multiple times until a thickness equal to or greater than the desired groove depth is obtained. The outermost surface of the multifunctional ultraviolet curable resin is formed into a gel state, and the monofunctional ultraviolet curable resin is used on the outermost surface of the multifunctional ultraviolet curable resin that has been made into a gel state in the thick film forming process. A gray color characterized in that the resin coating step and the exposure step are repeated a plurality of times to duplicate a grating with a desired film thickness, and the duplicated grating is peeled off from the mold in a peeling step. Teing replication method. 2. In the resin coating step, a monofunctional ultraviolet curable resin is poured into a mold fixed on a rotating table, and in the exposure step, the rotating table is rotated and UV exposure is carried out simultaneously with or after the rotation, and the monofunctional ultraviolet curable resin is The UV curable resin is gelled or completely cured, and the resin coating step and the exposure step are repeated multiple times in the groove and thick film forming step to form a gray layer with the desired groove depth and desired film thickness. 1. A grating duplication method, comprising: duplicating a grating, and peeling the duplicated grating from the mold in a peeling step.