JPH04129075A - Optical memory incorporating rotary recording medium - Google Patents

Abstract

PURPOSE:To effectively prevent flaws of a disk recording face due to collision with the case side by providing a thick projecting part in a position distant from an information recording part. CONSTITUTION:A projecting part 2 is produced in non-information recording part on the inside of upper and lower faces of a disk 1 as one-body forming. Therefore, step coverage is prevented to attain uniform film formation when a recording film is formed by sputtering or vacuum deposition, and consequently, a problem that information of recording, erasing, and reproducing signal are damaged is eliminated. Since the side of the projecting part 2 is detained on the case inside wall surface when the disk 1 is storage in a case, the recording face of the disk 1 is effectively prevented from being flawed by collision with the case side. Thus, the recording face of the disk is prevented from coming into contact with the casing inside to read out information with a high precision.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention includes an optical recording medium that rotates around a central axis inside a case, and a laser beam is focused on the optical disk through the case by rotating the optical disk. An optical memory that has a built-in optical disk and has a recording layer on which information is recorded, reproduced, or erased through any or all of the processes such as recording, reproducing, or erasing information, and the non-information recording area inside the optical disk is accessed from other parts. The present invention relates to an optical memory in which the information recording surface is held in a non-contact state within a case by using a thick protrusion, thereby preventing the information recording surface from being damaged when the optical disk is not rotated or rotated.

[Conventional technology]

Conventionally, various information sources have been used, such as record discs with grooves formed on the surface to record information, compact discs (CDs) and laser discs (LDs) with bits formed on the substrate, and information recorded magnetically. A large number of floppy disks (FD) and recording/playback (DRAW) disks have been developed and used.

By the way, these disks are usually housed in a certain container when they are not in use, in order to prevent dirt, dust, etc. from adhering to them from the outside, or from damaging them. Namely, as such containers, for example, bag-shaped containers, square casings, and the like are known, and the disk can be taken out from inside the container when used.

However, with this type of disc, when the disc is taken out and used, there is a risk that the disc may be accidentally hit against something and damaged, which poses a problem.

Therefore, nine containers have been proposed and developed in which the disk can be used with the disk inside (hereinafter referred to as a closed type). That is, bag-shaped containers, such as those for floppy disks (FD), are known as such containers, and such containers are designed to rotatably store disks inside. Information is read through a partially opened portion of the container.

However, in a container having such a structure, the recording surface of the disk comes into direct contact with the inner wall surface of the container during handling, so that the recording surface is easily scratched and the accuracy of the read information is impaired.

Therefore, as a known example to solve this problem, JP-A-1-22
No. 3681 and JP-A-2-61872. These contents include providing a thicker protrusion in the non-information recording portion on the outer peripheral edge side of the disk than in other information recording portions so that the recording surface does not come into direct contact with the casing.

[Problem to be solved by the invention]

However, such a conventional disk shape has the following problems. (1) Since the information recording part is lower than the non-information recording part, when a recording film is formed by sputtering or vacuum evaporation, step coverage occurs and uniform film formation cannot be achieved6. , there is a problem that information in the reproduced signal is lost. To prevent this, the information recording section should be separated from the non-information recording section.

A new problem arises in which the recording density decreases. (2) The protrusion is manufactured by integral molding. Therefore, since the wall thickness is locally different between the information recording portion and the non-information recording portion, the amount of shrinkage of the resin differs in this portion when the resin solidifies, and the substrate is deformed. Deformation of the substrate causes tracking error and focus error, resulting in a problem in which information cannot be read.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical memory that prevents the recording surface of a disk from coming into contact with the inside of a casing and allows information to be read with high precision.

[Means to solve the problem]

In order to achieve the above object, the present invention provides (1) a thicker protrusion in the non-information recording area inside the disk than in other areas. That is, the inner side of the disk has a larger space than the outer circumference in order to provide a hub for clamping the disk to the spindle motor. Furthermore, since there is a limit to how close the optical head can be to the center of the disk, the space inevitably becomes large. The present invention is characterized in that it takes advantage of this human pace, and a thick protrusion is provided at a position away from the information recording section. Regarding (2), the difference in level between the protrusion and other parts was eliminated and a taper was added.

[Effect]

By using the above means of the present invention, as for (1), since the thick protrusion is provided at a position away from the information recording section, step coverage is reduced when the recording film is formed by sputtering and vacuum evaporation. can be prevented and uniform film formation can be obtained. Therefore, record.

This eliminates the problem of erasure and loss of information in the reproduced signal. When the disc of the present invention is placed in the case, the protrusion side is locked to the inner wall of the case, so that
This can effectively prevent the disc recording surface from colliding with the case side and causing scratches. Further, when the disk is clamped to the spindle motor, the protrusion 8 is set without contacting the inner wall of the case, so that it can rotate freely. Regarding (2), since the step between the protrusion 8 and other parts is eliminated and a taper is added, extreme deformation of the board is eliminated, and tracking errors and focusing errors can be prevented.

This solves the problem of loss of information in recorded, erased, and reproduced signals.

〔Example〕

Examples of the present invention will be described. FIG. 1 is a plan view of a disk according to an embodiment of the present invention (a) and a sectional view taken along line B-B (b).
shows. A protrusion 2 according to the present invention is provided in a non-information recording area inside the disc 1.

The protrusions 2 are provided on both the upper and lower surfaces of the disk and are manufactured by integral molding. In FIG. 2, the size of the disk is 2 inches, the thickness is 0.5 m, and the step of the protrusion 2 has a thickness of 0.1 mm and is provided at a position 311I11 away from the information recording section. The hub 4 is provided in the center, and the plan view and B-
A cross-sectional view taken along line B is shown. The size of the card used was credit card size (54 x 85 mm). When the disk is not rotating as seen from the cross-sectional view taken along the line B-B, the protruding portion 2, which is a non-information recording portion, is in contact with the inner surface of the case, but the information recording portions other than the protruding portion 2 are not in contact. Figure 3 is a cross-sectional view of the spindle motor 5 and the clamped card B shown in Figure 2.
-A cross-sectional view taken along line B is shown. The disc is clamped onto the hub (
magnetic material) is attracted and clamped. In this case, the protrusion 2 is set so as not to come into contact with the inner surface of the card case. It is rotated by a spindle motor 5. Fourth
The figure shows a cross-sectional view of the boundary between the protrusion 2 of the present invention and other parts (information recording parts) of the disc 1. A characteristic feature is that the boundary between the protrusion 2 and other parts is tapered.

According to the present invention, the difference in the amount of shrinkage during solidification of the resin is alleviated, and deformation of the substrate is suppressed. Further, by tapering, step coverage is relaxed, the information recording section can be brought closer to the protrusion 2, the recording area is expanded, and the recording density is improved. FIG. 5 shows a modification of the protrusion 2. As shown in FIG. The shape of the protrusion 2 may be locally provided as shown in the figure.

〔Effect of the invention〕

According to the present invention, since the thick protrusion is provided at a position away from the information recording section, when a recording film is formed by sputtering or vacuum evaporation, step coverage can be prevented and uniform formation can be achieved. A membrane is obtained.

Further, when the disc is housed in the case, the protrusion side is locked to the case inner wall surface, thereby effectively preventing the disc recording surface from colliding with the case side and causing scratches. Furthermore, the difference in level between the protrusion and other parts has been eliminated and it has been tapered.

We were able to suppress the deformation of the board.

[Brief explanation of drawings]

Fig. 1 is a plan view (a) and a sectional view (b) of a disk according to an embodiment of the present invention, and Fig. 2 is a plan view (a) and a cross-sectional view of a card containing the disk in a credit card size. '
3 is a sectional view of the spindle motor and a sectional view taken along the line A-A' shown in FIG. Cross-sectional view of the boundary of , 5th
The figure shows a sectional view of a modified example of the protrusion. 1... Disk, 2... Protrusion, 3... Card,
4...Hub, 5...Hub, 6...Spindle motor, 7...Objective lens.

Claims (1)

[Claims] 1. A hub for connecting to an external rotational drive source is provided in a pair of cases with retention properties, an optical recording medium that rotates about a central axis is housed, and the transparent case is 1. An optical memory in which recording and reproduction is performed by irradiating a laser beam onto the disk, characterized in that a non-information recording portion inside the disk is provided with a thicker protruding portion than other portions. 2. The disk according to claim 1, wherein the protruding portion is integrally molded in the shape of a thick ring. 3. The disk according to claim 1, wherein the protruding portion protrudes above and below other parts. 4. The disk according to claim 1, wherein the disk is housed in a case and has a height that allows the disk to rotate without contacting the protrusions. 5. The optical memory according to claim 1, wherein the case has a credit size and the disc is housed in the case.