JPH0430650Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information recording medium that records and reproduces information using light such as a laser beam and thermal energy.

[Prior art]

The recording film on the substrate is melted and evaporated by irradiation with an energy beam such as a laser beam, forming pits.
In an information recording medium for recording information, as shown in a cross-sectional perspective view in FIG. 9, in order to protect the recording film,
The two transparent substrates 2 on which the recording films 1 are formed are fixed concentrically through a ring-shaped inner spacer 3 and an outer spacer 4 with the recording films 1 facing each other. Sanderch structure with air gap 5 (Japanese Patent Application Laid-Open No. 172551/1983)
It is becoming.

Therefore, the recording film 1 is completely isolated from the outside, protected from dust, and is free from scratches. However, since the transparent substrate 2 must transmit laser light for recording and reproducing information, it cannot be made too thick, and inner spacers 3 are arranged at the inner and outer circumferences of the transparent substrate 2. Also, sufficient mechanical strength cannot be obtained with only the outer spacer 4, and the outer periphery of the recording medium may sag due to its own weight.
Large warpage or waviness occurs.

Therefore, the present applicant filed an application for an information recording medium having a structure as shown in FIG. This information recording medium consists of two transparent substrates 2, 2 on which a recording film 1 is formed, a ring member 4 having approximately the same outer diameter as the substrate 2, and a disk member 3 having a smaller diameter than the inner diameter of the ring member 4. The transparent substrates 2, 2 are arranged concentrically and faced to each other, and are fixed at the inner and outer peripheral portions of the transparent substrates 2, 2. A holding member 6 is provided between the ring member 4 and the disc member 3, and is attached to the ring member 4 and slidably supports the outer peripheral end of the disc member 3. The occurrence of warping or waviness of the information recording medium is greatly suppressed.

[Problem that the invention attempts to solve]

Although the information recording medium configured in this way can prevent warping, the weight of each part in the circumferential direction of the information recording medium is There is a problem that the weight is not uniform and the weight is unbalanced in the circumferential direction. and,
If such a weight imbalance is large, abnormal vibrations will occur in the information reading device and the tracking servo will be adversely affected.

[Means for solving problems]

In order to solve the above-mentioned problem, the present invention aims to improve the size of the holding member for slidably holding the ring member between the ring member and the disk member arranged between two substrates facing each other. It is an object of the present invention to provide an information recording medium in which warpage and weight imbalance do not occur by adjusting the weight imbalance caused by the ring member and the disc member by using different materials.

The information recording medium of the present invention has two substrates arranged concentrically facing each other with a spacer interposed therebetween, and an information recording film is formed on at least one of the opposing surfaces of the substrates without contacting the spacer. In the recording medium, a ring member having substantially the same outer diameter as the substrate and a disk member having a smaller diameter than the inner diameter of the ring member are disposed between the substrates facing each other, and the ring member and the disk A plurality of holding members are provided in the circumferential direction of the ring member to slidably hold the disc member across the ring member, and the holding members have different dimensions or materials to balance the weight of the information recording medium. It is characterized by having a

[Effect]

Since the ring member and the disk member are arranged concentrically between the two substrates and support the outer and inner circumferential portions of the substrates, warping or waviness does not occur in the information recording medium. Further, since a holding member having different dimensions or materials is provided between the ring member and the disc member, the imbalance in the weight of the information recording medium is eliminated.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof. FIG. 1 is a sectional view of an information recording medium according to the present invention, and FIGS. 2 to 7 are external perspective views of a holding member used for the information recording medium according to the present invention.

In FIG. 1, two transparent substrates 20, 20 on which a recording film 10 is laminated are connected to a ring member 30 having approximately the same outer diameter as this substrate 20, and a ring member 30 which is arranged concentrically therewith. A disc member 31 having a diameter smaller than the inner diameter is sandwiched between the disc members 31 and is bonded to face each other.

The disc member 31 has a thinner portion except for its center, that is, the portion facing the recording film 10.
It is formed so as not to come into contact with the recording film 10.
Further, the outer diameter of the disk member 31 is the same as that of the ring member 30.
Since the diameter is smaller than the inner diameter of the ring member 30, an appropriate gap G is formed between the disc member 31 and the ring member 30.

The holding members 40s and 40l are cylindrical pins, one end of which is inserted from the outer surface to the inner surface of the ring member 30, and the other end is fixed to the ring member 30. It is slidably inserted into a hole 31a formed from the outer peripheral surface toward the center thereof.

The holding members 40l and 40s are selected and disposed at predetermined positions with predetermined dimensions or predetermined weights, taking into consideration the weight imbalance in the circumferential direction of the information recording medium.

FIG. 1 shows an information recording medium whose weight is unbalanced in the circumferential direction, with the right side of the figure being heavier and the left side being lighter.
Therefore, a short and light holding member 40s made of the same material and the same diameter is placed on the right side of the information recording medium, and a similarly long and heavy holding member 40l is placed on the left side to balance the weight. We are trying to Note that the holding members 40l and 40s are arranged, for example, eight times in the circumferential direction of the ring member 30, but this is just one example, and the equal intervals are appropriately selected depending on the state of weight imbalance.

FIGS. 2 and 3 show the holding members 40s and 40.
FIG. 1 is a perspective view of a cylindrical tube, showing a short columnar column and a long columnar column.

FIG. 4 shows the short and long holding members 40s, 4.
It is a perspective view of 40 m of holding members of intermediate length of 0l, and is cylindrical like the above-mentioned.

5 and 6 are perspective views of threaded holding members 50s and 50l each having a groove 50a on one end and a threaded portion 50b formed thereon.
7 is a perspective view of a similar holding member 50m having a length intermediate between the holding members 50s and 50l.

Such screw-shaped holding members 50s, 50l,
50m is provided with a screw hole 30a in the ring member 30 as shown in the enlarged view of the main part in FIG.
Install by screwing in from the outer circumferential side of 0 using a tool.

By the way, the specific dimensions of the information recording medium of this example are as follows. The transparent substrate 20 is made of resin such as acrylic or polycarbonate, and has a diameter of 30 cm and a thickness of 1.2 to 1.5 mm. Ring member 30
The disc member 31 and the transparent substrate 20 are made of the same material, and the gap therebetween is 1 to 2 mm.

For this information recording medium, the balance state of the weight by the spacer is measured, and a long holding member of 40 l is used for the holding member placed in the light part, and a short size holding member is used for the holding member placed in the heavy part. Holding member 40s
Alternatively, by using 40 m to balance the weight, an information recording medium with balanced weight can be easily obtained. In addition, in order to balance the weight,
Although holding members having different dimensions and weights may be used, the holding members may be made of different materials. Furthermore, the balance can be further improved by using holding members whose weights are more minutely varied by making different materials and dimensions.

〔effect〕

As described in detail above, according to the present invention, it is possible to prevent the occurrence of changes in shape such as warping or waviness, and to provide a good information recording medium without weight imbalance. Furthermore, since the information recording medium has a balanced weight, it has the advantage that abnormal vibrations do not occur during rotation during use, and the tracking servo is not adversely affected.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an information recording medium according to the present invention;
2 to 7 are perspective views of a holding member used in the information recording medium of the present invention, FIG. 8 is an enlarged cross-sectional view of main parts with different holding members, and FIG. 9 is a cross-sectional perspective view of a conventional information recording medium. FIG. 10 is an enlarged sectional view of a conventional information recording medium. 10... Recording film, 20... Transparent substrate, 30...
Ring member, 31...Disc member, 40l, 40
s, 40m...Holding member (cylindrical), 50l, 5
0s, 50m...Holding member (screw shape).

Claims (1)

[Claims for Utility Model Registration] 1. Two substrates are placed concentrically facing each other with a spacer in between, and an information recording film is formed on at least one of the opposing surfaces of the substrates without contacting the spacer. In the information recording medium, a ring member having substantially the same outer diameter as the substrate and a disk member having a smaller diameter than the inner diameter of the ring member are disposed between the substrates facing each other, and the ring member and the circle A plurality of holding members are provided in the circumferential direction of the ring member to slidably hold the disc member while straddling the plate member, and the dimensions or materials of the holding members are varied to balance the weight of the information recording medium. An information recording medium characterized by the following. 2. The information recording medium according to claim 1, wherein the holding member has a cylindrical shape and is attached to the ring member by being inserted in its radial direction. 3. The information recording medium according to claim 1, wherein the holding member has a thread groove and is attached to the ring member by being screwed into the ring member in the radial direction thereof.