JPH0212680A - Optical floppy disk - Google Patents

Abstract

PURPOSE:To avoid any flaw onto a recording face of an optical disk and a recording medium, to attain thin profile and to improve the performance of storage and carrying by forming the inside of a cartridge opposite to a nonrecording part of an optical disk without provision of any optical recording medium high as a step. CONSTITUTION:The optical recording medium 12 is adhered to the recording part of a transparent disk base 11 of the optical disk 10 and a circular hole 10a is provided to the center. The nonrecording part 10b without provision of the optical recording medium is provided to the inner circumferential part and the outer circumferential part of the transparent base 11. Two large/small ring steps 13c, 13d in with the inner wall in press contact onto the nonrecording part 10b of the optical disk 10 is formed higher than the other part are provided to the inner side of the upper case 13a and the lower case 13b of the cartridge 13. Thus, even if an external force is applied to the cartridge 13 and deformed, the possibility of the damage caused by the contact between the optical recording medium 12 in contact with the inner wall of the cartridge 13 is precluded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical F7 disc that can record information by irradiating it with a laser beam and reproduce the information optically.

[Conventional technology] In recent years, compact discs and write-once discs have become popular.

Research and development and commercialization of optical information recording and reproducing systems such as erasable magneto-optical disks and optical disks using phase change materials are actively being carried out, and optical record carriers are being made smaller, more portable, and have larger storage capacity. Increased capacity is required.

FIG. 4(a) is a plan view of the optical disc 1, and FIG. 4(b) is a plan view of the optical disc 1.
FIG. 2 is a cross-sectional view of the optical disc l taken along line AA' of FIG. The optical disc 1 is a disc having a circular hole 1a at the center through which the shaft of a spindle motor is inserted, and has a non-recording portion 1b at the inner and outer peripheries. This optical disc 1 has a disk-shaped transparent substrate 2 and a back plate 3 with holes 2a and 3a in the center, respectively, and two large and small ring-shaped spacers 4 at the inner and outer circumference parts corresponding to the non-recording area 1b. It is pasted together. Information tracks are carved concentrically or spirally on the inner surface of the transparent substrate 2, and the optical recording medium 5 is provided on the information tracks. between the optical recording medium 5 and the back plate 3.

An air layer S having a thickness of about 0.4 mm is provided in order to prevent the recording sensitivity from decreasing when the back plate 3 and the optical recording medium 5 come into close contact. Furthermore, when an optical recording medium 5 made of an inorganic material is generally used, it is preferable that the optical recording medium 5 is sealed because the characteristics change due to humidity. However, recently developed optical recording media based on organic materials do not change their properties against humidity and do not need to be sealed.

Recording and reproduction of information on the optical recording medium 5 is performed by making a laser beam enter the light incident surface 2b of the transparent substrate 2 and forming a spot of 1 to several pm on the optical recording medium 5. Therefore, if scratches or dirt adhere to the light incident surface 2b of the transparent substrate 2, the accuracy during recording and reproduction will be affected, so a cartridge 6 for housing the optical disc 1 as shown in FIG. 5 has been developed.

FIG. 5(a) is a perspective view of the cartridge 6 when the optical disc l is stored in the cartridge 6, and FIG. 5(b) is a perspective view of the cartridge 6 shown in FIG.
It is a sectional view taken along line B'. The cartridge 6 has a rectangular upper case 6b and a lower case 6c with a hole 6a in the center.
It is manufactured by gluing or screwing, and houses the optical disc 1 inside. Optical disc l in cartridge 6
A long hole-shaped window 6d for recording and reproducing information is provided in the portion where the information is located, and a shutter 6e is provided in this window 6d so as to be openable and closable. The shutter 6e has a mechanism that opens when the cartridge 6 is installed in the information reading device and closes when it is removed, and prevents dust from entering and the user from accidentally touching the optical disc. There is.

However, in the optical disc 1, the transparent substrate 2 and the back plate 3 must be strictly adhered with the spacer 4 in between, which increases the number of manufacturing steps and increases the cost. Further, when the cartridge 6 is used, its thickness is about 10 mm, which makes it difficult to carry and requires a lot of space for storage.

[Objective of the Invention] The object of the present invention is to change the material of the optical recording medium and the internal structure of the cartridge so as not to damage the recording surface of the optical disc and the recording medium, and to reduce the thickness. An object of the present invention is to provide an optical floppy disk with improved storage and portability.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to provide an optical floppy disk in which an optical disk having an optical recording medium is housed in a cartridge, and a non-recording portion of the optical disk in which the optical recording medium is not provided. The optical floppy disk is characterized in that the inner side of the cartridge facing the cartridge is formed in a stepped manner.

[Embodiments of the Invention] The present invention will be described in detail based on embodiments illustrated in FIGS. 1 to 3.

tJIJ1 Figure (a) is a perspective view of an embodiment of the optical proppy disc according to the present invention, and (b) is a sectional view taken along line cc' in (a). The optical disc 1O has a disc-shaped transparent substrate 1
An optical recording medium 12 is attached to one recording section, and a circular hole 10a is provided in the center thereof. This transparent substrate 11
A non-recording portion lOb, in which no optical recording medium is disposed, is provided at the inner and outer circumferential portions of the recording medium. Cartridge 13
Inside the upper case 13a and the lower case 13b, there are two ring-shaped stepped portions 13c, one large and one small, in which the inner wall portion that contacts the non-recorded portion 10b of the optical disc 10 is higher than the other portions.
13d is provided. In addition, a window section 13 for recording and reproduction is provided.
As in the case of FIG. 5, a shutter 13f for closing the window 13e and the window 13e are provided. The stepped portions 13c and 13d prevent the optical recording medium 12 from coming into contact with the inner wall of the cartridge 13 and being damaged even if the cartridge 2 13 is deformed by external force.

Here, to explain the manufacturing method of this optical disc 10 by giving an example, as shown in FIG.
A pre-format such as a track and a pre-pit 14 such as a clock are provided on a disc-shaped transparent substrate 11 provided with a preformat 14 using a conventional technique such as injection, compression, or 2P method, as shown in FIG. 2(b). Pre-pits 1 are formed on the optical recording medium 12 by means such as coating or vapor deposition.
Provided on top of 4. In this case, if an organic material-based medium whose characteristics change little with humidity is used for the inner and outer circumferential parts of the optical recording medium 12, it is possible to seal the optical recording medium 12 by using spacers, back plates, etc., as in the past. This makes it possible to realize a thin optical disc 10.

In addition, the material of the transparent substrate 11 is preferably a material such as polycarbonate or polymethyl methacrylate (PMMA), which has optical precision with respect to the laser beam, and the material of the optical recording medium 12 is preferably a material that has small changes in characteristics due to humidity. anthraquinone derivatives, dioxazine compounds and their derivatives, triphuedithiazine compounds, phenanthrene derivatives, cyanine compounds, merocyanine compounds, biryllium compounds, xanthine compounds, triphenylmethane compounds, croconium dyes, azo dyes, crocon compounds,
Preferred are azines, indigoids, mitin dyes, azulenes, squalium derivatives, and the like.

Figure 3 is a blower showing a method for recording and reproducing information on an optical disc.
2 is a circuit configuration diagram, and the optical disc 10 is a cartridge 1.
3, the motor 21 is inserted into the hole 10a in the center.
By inserting the shaft portion 21a of the cartridge 1,
The shutter 13 is rotatably mounted inside the shutter 13.
f is brought into an open state by a mechanism not shown. Further, above the window portion 13e of the cartridge 13, an optical head 22 for recording and reproducing is installed, which includes a semiconductor laser, an objective lens, an actuator, a detector, a beam splitter, and the like. This optical head 22 has a feed screw 23.
A head drive motor 24 is connected to the head drive motor 24 via a guide shaft 2 for guiding the direction of drive by the feed screw 23.
5 are provided parallel to the radial direction of the optical disc.

A laser drive circuit 26 is provided at the recording signal input section of the optical head 22.
, modulation circuit 27 are connected in sequence. On the other hand, the reproduction signal output section of the optical head 22 includes an amplifier circuit 28 and a demodulation circuit 2.
9 are connected in sequence, and a servo circuit 30 for controlling autofocusing, autotracking, etc. is connected to the reproduction signal output section, and the control signal output of the servo circuit 23 is connected to an actuator in the optical head 22. .

With such a configuration, in response to the rotational movement of the optical disc 10 driven by the motor 21, the optical disc 22 is moved along the guide shaft 25 on the feed screw 23 by the head drive motor 24.
Since it is possible to move in the radial direction of the optical disk lO along
Optical head 2 for any track on optical disk 10
2 positions can be set.

When recording information on the optical disk 10, the information signal is modulated by MFM, FM, 2-7 conversion, etc. in the modulation circuit 27, and then sent to the semiconductor laser oscillator inside the optical head 22 via the laser drive circuit 26. It will be done. Then, a laser beam spot is focused on the surface of the optical recording medium 12 through the transparent substrate 11 of the optical disk 10 to a diameter of 1 to several μm, and information is transmitted by changing the shape or composition of the surface of the optical recording medium 12. Record.

Conversely, when reproducing information recorded on the optical disc 10, a laser beam of a certain level is applied to the optical recording medium 1.
This is done by detecting the reflected light obtained by irradiating the two surfaces with a detector within the optical head 22. The output signal of the detector is converted into an electric signal, amplified by an amplifier circuit 28, and then returned to the original signal by a demodulation circuit 29 to become a reproduced signal.

Control signals necessary for autofocusing and autotracking are processed by the servo circuit 30 and then sent to the actuator in the optical radar 22 to control the minute laser beam spot to scan a desired track.

Note that it is also possible to record information on both sides of the optical disc 10 if information is recorded and reproduced not from the transparent substrate 11 but from the opposite recording surface side.

[Effects of the Invention] As explained above, the optical floppy disk according to the present invention has a stepped portion on the inner wall of the cartridge that houses the optical disk so that only the non-recorded portion comes into contact with the inner wall of the cartridge to prevent scratches or the like on the recording surface of the optical disk. This has the advantage that the structure is simple and the manufacturing cost is low.

[Brief explanation of the drawing]

1 to 3 show an embodiment of an optical floppy disk according to the present invention, FIG. 1(a) is a perspective view of the embodiment, and FIG. 1(b) is a perspective view of the embodiment.
is a sectional view taken along the line CC' in (a), and Figure 2 (
a) and (b) are cross-sectional views of the optical disc manufacturing method;
The figure is a block circuit configuration diagram for recording and reproducing information on an optical disk, and FIG. 4(a) is a plan view of a conventional optical disk, and FIG. , 5th
Figure (a) is a perspective view of a conventional optical floppy disk, (b)
is a sectional view taken along line BB' in (a). Reference numeral 10 is an optical disk, 11 is a transparent substrate, 12 is an optical recording medium, 13 is a cartridge, and 13c and 13d are stepped portions. Patent applicant: Canon Corporation Figure 1 (CI) (b Figure 3 Figure 4 @ (b)

Claims (1)

[Claims] 1. An optical floppy disk in which an optical disk having an optical recording medium is housed in a cartridge, characterized in that the inner side of the cartridge facing the non-recording portion of the optical disk where the optical recording medium is not provided is formed high in a stepped manner. An optical floppy disk.