JPH01277344A - Information recording medium - Google Patents

Abstract

PURPOSE:To reduce the deviations of eccentricity values and coaxial degrees of two boards and to attain sure access even at the time of simultaneously executing information processing on both the faces of a board by positioning both the boards by laser beams so that a boundary between a circular mirror face part and an information recording part of one board coincides with that of the other board and sticking both the boards to each other. CONSTITUTION:The circular mirror face parts 7 having the same radium around a rotational center hole 5 are formed on 1st and 2nd boards 2, 3 adjacently to the information recording parts 8a and both the boards 2, 3 are positioned by using a laser beam a' so that the boundaries 14 between the mirror face parts 7 and the recording parts 8a coincide with each other and stuck to each other. Thereby, the coaxial degrees of the 1st and 2nd boards 2, 3 are logically '0' and the eccentricity values of the 1st and 2nd boards 2, 3 at the time of mounting them on a medium rotating means such as a turn table can be uniformed. Even when information processing to the information recording parts 8 of both the boards 2, 3 is simultaneously executed, sure access can be attained.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an information storage medium having a vertical structure.

(Prior Art) In recent years, various information storage media that are formed by bonding two substrates each having an information recording section on which information can be recorded have been put into practical use as information storage media capable of high-density recording.

Conventionally, this type of information storage medium has been constructed by bonding two substrates together with their rotational center hole as a reference. Furthermore, a guide groove (track) that serves as a guide for laser light is formed in the information recording section where information can be recorded, so that stable information processing can be performed.

(Problem to be Solved by the Invention) However, when the above-mentioned substrates are simply pasted together, a deviation occurs in the eccentricity and coaxiality of the two substrates, and while the information storage medium is rotated, information is recorded on that side substrate. There is a serious problem in that when information processing such as recording/reproducing is performed on a part at the same time, access may not be possible.

The present invention was made based on the above circumstances, and its purpose is to bond two substrates together with little deviation in eccentricity and coaxiality, and to ensure that information processing on both sides is performed simultaneously. The object is to provide an information storage medium with excellent information processing characteristics that can be accessed.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a first lens system having a rotation center hole and an information recording section on which information can be recorded. An information storage medium comprising a second substrate, the information storage medium comprising the first substrate. An annular mirror surface portion having the same radius centered on the rotation center hole is provided on the second substrate adjacent to the information recording section, and a laser beam is used to align the boundary between the annular mirror surface section and the information recording section. and position it first. It is constructed by bonding a second substrate.

(Function) That is, the present invention has the following features. An annular mirror surface portion having the same radius centered on the rotation center hole is provided on the second substrate adjacent to the information recording section, and a laser beam is used to position the annular mirror surface portion so that the boundary between the annular mirror surface portion and the information recording portion coincides with each other. First. Since the second substrate is bonded together, the coaxiality between the first substrate and the second substrate is theoretically 0, and the amount of eccentricity when attached to a media rotation means such as a turntable is both. Both boards can be made the same =, thereby making it possible to reliably access the information recording sections of both boards even when information processing is performed at the same time.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 6.

Fig. 2 schematically shows an information storage medium with a laminated structure and its information processing state, and 1 in the figure shows the information storage medium (
(hereinafter referred to as an optical disk), and this optical disk 1 is made of a transparent synthetic resin material such as polycarbonate (PC).
It has a structure in which a first substrate 2 and a second substrate 3, which are formed from resin into a disk shape of the same size, are bonded together with a reinforcing plate 4 that also serves as a spacer sandwiched therebetween.

Above 1. The second substrates 2.3 each have, for example, an outer diameter of about 130M, a diameter of the rotation center hole 5 formed at the rotation center of about 15211JI, and a thickness of 1 to 2rtm.
Te (tellurium) is formed on the mutually opposing surfaces.
The information recording layer 6 is formed by vapor-depositing a metal such as the like, and is formed in a wide annular shape. As shown in FIG. 3, this information recording layer 6 is formed with a narrow annular mirror surface portion 7 located approximately in the middle and centered on the rotation center hole 5, and this annular mirror surface portion 7 extends in the radial direction. A first information recording section 8a located inside the annular mirror surface section 7 in a state of being divided into two parts, and a first information recording section 8a located inside the annular mirror surface section 7;
A second information recording section 8b located outside is formed.

Further, as shown in FIG. 4, the portions of the substrate 2.3 corresponding to the first information recording section 8a and the second information recording section 8b have a width of, for example, 0.6. o, height 800 people, pitch 186
P guide grooves (tracks) 10 are formed.

Then, a recording/playback head 1 equipped with a semiconductor laser is installed.
The position of the laser beam a of 1 (see FIG. 2) is controlled so that it always faces the guide groove 10. Also,
The optical disk 1 is rotationally driven by a spindle motor 12 as a medium rotation means, and the recording/reproducing head 1
1.11 can be moved in the radial direction.

By irradiating the laser beam a with increased output, the information recording sections 8a and 3b are provided with holes (
bits) etc. are opened and information is recorded. Further, during reproduction, the laser beam a with reduced output is irradiated along the guide grooves 10, and the reflected light (or transmitted light) thereof is detected by means not shown, so that the information recording section 8a
, 8b is reproduced.

Also, 1st. The second substrate 2.3 is bonded together so that the annular mirror surface portions 7.7 formed at the same radius around the rotation center hole 5 are aligned as will be described later, and the relative eccentricity and The configuration is such that the coaxiality is theoretically "0".

FIG. 1 shows a first example using the annular mirror surfaces 7, 7. A positioning means 13 for positioning the second substrate 2.3 is shown, and this positioning means 13 is connected to the first information recording section 8a (or second information recording section 8b) having the guide groove 10.
A plurality of (four sets in this example) laser optical systems 15a, 15b, 15 are arranged so that the boundary 14 between
c.

15d for positioning. Laser optical systems 15a, 15b, 15c, and 15d include laser light sources 16 arranged on a circle having the same diameter as the boundary 14 and at equal intervals.
It consists of a half mirror 17 provided directly below this laser light source 16, and a photodetector 18 provided in the direction of reflection of this half mirror 17.

First, the second substrate 3 is held by a second substrate holding and moving means (not shown) and positioned below the positioning means 13, and the four laser optical systems 15a, 15b, 15c,
Laser light a emitted from laser light source 16 of 15d
'... is irradiated onto the second substrate 3, and the reflected light a'...
. is reflected by the half mirror 17 and guided to the photodetector 18 . . . and the second substrate holding and moving means is moved in the X-Y direction. Then, all the laser optical systems 15a to 15d stop when detecting the boundary 14 of the second substrate 3 to maintain this state.

Next, the first substrate 2 held by the first substrate holding and moving means (not shown) is interposed on the upper surface side of the second substrate 3, and all the laser beams a are removed as in the case of the second substrate 3 described above.
'... stops when it detects the boundary 14 and maintains this state.

As a result, the annular mirror portions 7.7 of the same radius formed on the first substrate 2 and the second substrate 3 are brought into alignment, and the relative eccentricity and coaxiality of the side substrates 2.3 are theoretically Actually, it is in the state of "0".

FIGS. 5(a) and 5(b) show the principle of detecting the boundary 14 using laser light. FIG. 5(a) shows in red the state in which the boundary 14 between the annular mirror surface part 7 and the information recording part 8a having the guide groove 10 is irradiated with the laser beam a', and FIG. 5(b) shows
The output level from the mirror surface section 7 to the information recording section 8a in the photodetector 18 is shown. Photodetector 1
The reflected light a' detected at 8 is smaller at the information recording section 8a (or 8b) having the guide groove 10 than at the annular mirror surface section 7 due to the diffraction effect, so if we take the point where the light intensity changes, we can find it there. It can be determined that is the boundary 14.

In addition, as shown in FIG. 6, each photodetector 18.
... are connected to the control device 20, and when the control device 20 determines that the alignment of the side substrates 2.3 is completed, an operation start signal is sent to the bonding device 21,
3 are bonded together with the reinforcing plate 4 interposed therebetween.

The optical disc 1 configured in this way includes two substrates 2.
3 is "0", and the eccentricity of the guide groove 10 with respect to the rotation center hole 5 of the side substrate 2.3 is the same. For example, if the eccentricity of the first substrate 2 when the rotation center hole 5 of the first substrate 2 is attached to the spindle motor 12 of an information processing device such as an optical disk device is 307151, then the second substrate The eccentricity of 3 is 30. It becomes n. In this way, the eccentricity of the side substrates 2.3 becomes equal, and as shown in FIG. This is very effective when simultaneously recording/reproducing information on the second substrate 2.3.

In the above embodiment, the annular mirror surface section 7 is present between the information recording sections 8a and 8b which are divided into two in the radial direction. However, the present invention is not limited to this. For example, as shown in FIG. The substrate 21 has an annular mirror surface 7 formed along the outer periphery of the information recording section 8 as shown in FIG. Alternatively, as shown in FIG. 8, substrates 2' and 3' having an annular mirror surface 7 formed along the inner periphery of the information recording section 8 may be formed, and these may be bonded to each other.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist thereof.

[Effects of the Invention] As explained above, the present invention has the effect of being able to provide a bonded information storage medium.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the positioning principle of the base and buttock in the process of making an embodiment of the information recording medium of the present invention, and Figure 2 is a diagram showing the information storage medium and its information processing state.
Figure 3 is a plan view of the substrate of the information storage medium viewed from the information recording layer side, Figure 4 is an enlarged sectional view of the main parts, Figure 5 is an explanatory diagram showing the boundary detection principle, and Figure 6 is the control system. The block diagrams shown in FIGS. 7 and 8 are diagrams showing other different examples of the substrate. DESCRIPTION OF SYMBOLS 1... Information storage medium (optical disk), 2... First substrate, 3... Second substrate, 5... Rotation center hole, 7...
... Annular mirror surface section, 8.8a, 8b... Information recording section, 1
4... Boundary, a'... Laser light. Applicant's agent Patent attorney Takehiko Suzue 5a Figure 1 Figure 2 - Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] An information storage medium comprising first and second substrates each having a rotation center hole and having an information recording section on which information can be recorded, the first and second substrates having a rotation center hole centered on the rotation center hole. An annular mirror surface portion having the same radius is provided adjacent to the information recording section, and a laser beam is used to position the annular mirror surface portion so that the boundary between the annular mirror surface portion and the information recording portion coincide with each other, and the first and second substrates are An information storage medium characterized by being constructed by pasting together.