JPH02177027A - Optical disk - Google Patents

Abstract

PURPOSE:To enhance the ratio of a recorded area to the area of an optical disk and to accomplish the large capacity of the disk by constituting both a land surface and a groove surface as the recorded area in the optical disk where the land surface and the groove surface having different heights are alternately arranged in a radial direction. CONSTITUTION:The dimensions of the respective widths of the land surface 2 and the groove surface 3 are the same and the surfaces 2 and 3 are formed in the dimension where recording is possible so as to constitute both of them as the recorded area. By positioning an optical pickup at a position opposed to the land surface 2, a pit 5 is formed to perform recording and also readout is performed with reflected light from the pit 5. Next, by positioning the optical pickup at a position opposed to the groove surface 3, the recording and readout are performed in the same way. At such a time, an inclined surface 4 serves as a guard. Thus, the ratio of the recorded area to the area of the disk is enhanced and the large capacity of the disk is accomplished by performing recording on both surfaces 2 and 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical disc that has a land surface and a groove surface.

[Summary of the Invention] The present invention provides an optical disc in which land surfaces and groove surfaces of different heights are arranged alternately in the radial direction, and by configuring both the land surface and the groove surface as a recording area, The ratio of the recording area increases, resulting in a large capacity.

[Prior Art] An optical disk has land surfaces and groove surfaces alternately formed in the radial direction in a concentric or spiral shape. Conventional examples of such optical disks are shown in FIGS. 3 and 4, respectively, and FIGS. 3 and 4 are partial sectional views of the optical disk cut in the radial direction, respectively.

In FIG. 3, high-position land surfaces 2 and low-position groove surfaces 3 are alternately arranged, and an inclined surface 4 is formed between each adjacent land surface 2 and groove surface 3. The land surface 2 is formed to have a recordable width, and the groove surface 3 is formed to have a narrower width d.
is configured as a recording area. Similarly, in FIG. 4, land surfaces 2 and groove surfaces 3 are arranged alternately, and an inclined surface 4 is formed between each adjacent land surface 2 and groove surface 3. However, unlike FIG. 3, the groove surface 3 is formed to have a recordable width, and the land surface 2 is formed to have a narrower width d, and the groove surface 3 is configured as a recording area.

An optical pickup is positioned opposite the land surface 2 or groove surface 3 configured as a recording area, and recording and reading are performed using laser light output from the optical pickup. Slanted surfaces 4 located on both sides of the land surface 2 or groove surface 3, which is irradiated with laser light, serve as guards during recording and reading using laser light.

[Problems to be Solved by the Invention] L7 However, in the above two conventional examples, only one of the land surface 2 and the groove surface 3 is configured as a recording area, and the other surface is not used for recording. Therefore, the ratio of the recording area to the disk area is low, making it unsuitable for large capacity storage.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical disc that has a high ratio of recording area to disc area and is suitable for increasing capacity.

[Means for Solving the Problems] In order to achieve the above object, the optical disc of the present invention has a land surface and a groove surface that are formed concentrically or spirally with respect to the center of rotation and have different heights. The land surfaces and groove surfaces are arranged alternately in the direction, and the land surfaces and groove surfaces are each provided with a recordable width, and each is configured as a recording area.

[Operation] Since recording is performed on both the land surface and the groove surface, the ratio of the recording area to the disk area is high.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

One embodiment of the invention is shown in FIGS. 1 and 2.

In FIG. 2, a center hole 1 is formed at the center of the optical disk, and a recording section of a constant width is formed on the upper surface (or upper and lower surfaces) of the optical disk with the center hole 1 as the center.

The optical pickup of the drive device is configured to be movable in the radial direction of the optical disc, and is displaced within the recording section I7. In this recording section, a land surface 2 and a groove surface 3 are formed concentrically or spirally around the center hole 1, and the detailed structure thereof is shown in FIG.

FIG. 2 shows a perspective view with a cross section in the radial direction (detailed cross-sectional structure is omitted). 1
They are arranged alternately in the direction of the arrow in the figure). The land surface 2 and the groove surface 3 have the same width and are formed to a recordable size, and both the land surface 2 and the groove surface 3 are configured as a recording area. Furthermore, a certain interval is placed between the adjacent land surface 2 and groove surface 3, and this portion is formed as an inclined surface 4. The angle of inclination and height difference of the inclined surface 4 are determined in consideration of the ability of the optical pickup so as not to be influenced by the adjacent land surface 2 or groove surface 3 during recording/reading of the optical pickup. In addition, if the inclination angle 4 is not formed between the adjacent land surfaces 2 and groove surfaces 3, the width of each land surface 2 and groove surface 3 is recorded.
It is necessary to make it wide so as not to be affected by the adjacent land surface 2 or groove surface 3 during reading.

The operation of the above configuration will be explained below.

An optical pickup is positioned opposite the land surface 2, and a bit 5 is formed to perform recording, and reading is performed using reflected light from the bit 5. Next, the optical pickup is positioned opposite the groove surface 3, and recording and reading are performed in the same manner. During this recording/reading, the inclined surfaces 4 located on both sides of the land surface 2 or the groove surface 3 to which the laser beam is irradiated serve as guards. In this way, since it is possible to record on both the land surface 2 and the groove surface 3, the ratio of the recording area to the disk area is large.

Further, the order of recording on the land surface 2 and recording on the groove surface 3 may be in the same direction from the inner circumferential side to the outer circumferential side or may be in different directions. Furthermore, the recording on the land surface 2 and the recording on the groove surface 3 may be performed alternately, and the rotation directions may be either the same or opposite directions. Furthermore,
Can be applied to both recording methods (optical recording and magneto-optical recording).

[Effects of the Invention] As described above, according to the present invention, in an optical disc in which land surfaces and groove surfaces having different heights are arranged alternately in the radial direction, both the land surface and the groove surface are configured as a recording area. Therefore, the ratio of the recording area to the disk area is high and the capacity can be increased.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, FIG. 1 is a partial perspective view of an optical disk having a radial cross section, and FIG.
This figure is a plan view of an optical disk, FIG. 3 is a partial sectional view of an optical disk showing a conventional example, and FIG. 4 is a partial sectional view of an optical disk showing another conventional example. 2...Land surface, 3...Groove surface. No. 1 Plan of the nine-task disk Fig. 2

Claims (1)

[Claims] (1) Land surfaces and groove surfaces of different heights formed concentrically or spirally with respect to the center of rotation are arranged alternately in the radial direction, and these land surfaces and groove surfaces can be recorded respectively. An optical disc characterized in that the optical disc is provided across the width of the disc, each of which is configured as a recording area.