JPH02239463A - Optical disk device - Google Patents

Abstract

PURPOSE:To shorten the access time by keeping the revolving speed of a disk faster at the time of recording and reproducing information in a retrieval area than in a recording area. CONSTITUTION:The disk revolving speed at the time of recording and reproducing the information in the retrieval area 1 is kept faster than at the time of recording and reproducing the information in the recording area 2. In other words, when the information is recorded and reproduced on an optical disk, the number of revolutions of the disk is changed between the retrieval area 1 and the recording area 2, so as to be at a high speed at the recording and reproducing the retrieval area 1, and to be at a low speed as slow as a CD. Consequently, the area of a recording bit is reduced as much as possible by lowering the revolving speed at the time of recording and reproducing the information on the recording area 2 to enable the recording density to be promoted. By this method, the access time can be shortened.

Description

[Detailed Description of the Invention] [Summary] With respect to an optical disc having a search area and a recording area within the same disc, the purpose of this invention is to reduce the access time by using a disc when recording and reproducing information in a search area. Configuring an optical disc device to keep the rotational speed faster than when recording and reproducing information in a recording area [Field of Industrial Application] The present invention relates to an optical disc that shortens information retrieval time.

Optical disks include compact disks (abbreviated as CDs), which have a reflective film made of a thin metal film on a disk-shaped resin substrate and record information in the form of bits on the substrate. (Read On
It is called ly memory (abbreviated as ROM).

In addition, there are optical disks in which a recording film is formed on a substrate using a material that is easily melted and removed, such as tellurium (Te), and information is formed in the form of bits on the recording film, and the information is detected by the presence or absence of pits. Write once memory
Men+ory).

In addition, magneto-optical discs use the fact that the recording film is made of a perpendicularly magnetized magnetic film and the rotation direction of polarized light differs depending on the magnetization direction to record and reproduce information. There are also phase-change optical disks that record and reproduce information using changes in the reflectance of the recording film, and these are called rewritable memories. As described above, there are various types of optical disks, but they can be broadly divided into read-only memories such as CDs, and writable memories such as write-once memories and rewritable memories. The present invention relates to a usage method applicable to such various optical discs.

[Conventional technology]

As mentioned earlier, there are different types of optical disks, and depending on the purpose, read-only memory or writable memory is used. In some cases, these optical discs are used to record information in series, but in most cases there is a search area at the start of recording, followed by a recording area, and the search area is It is configured to facilitate access to desired information by detecting information. For example, in the case of a CD, there is a search area at the start of playback.
ID such as the sector number and track number of the recording area where music is recorded.
n) information is recorded, and when the user specifies the song number, the optical head tracking along the guide groove detects the required ID information from the reflected laser light and immediately It is configured to jump to the sector of the specified track and start playback while counting the track number. The same applies to book discs that contain a large number of documents; ID information for each recording area in which documents are recorded is recorded in the search area at the beginning of the book, and by detecting the ID information, It is structured to allow quick access to documents.

However, as the use of optical disks increases, there is a demand for further reduction in access time.

[Problem to be solved by the invention]

As mentioned above, when reproducing necessary information from a large amount of information recorded on an optical disc, conventionally, a search area and a recording area are provided on the inner and outer periphery of the optical disc, and the recording area is used to record information. ID information of the information is recorded in the search area, and when reproducing the information, the optical head accesses the sector in which the information is recorded by detecting the [0 information in the search area and reproduces the information. However, the challenge is to shorten the access speed even more than currently. (Means for solving the problem) The above problem is to record the rotational speed of the disk when recording and reproducing information in the search area in an optical disk that has an information search area and a recording area in the radial direction of the disk. This problem can be solved by configuring the optical disk device so that the speed is maintained faster than when recording and reproducing information in the area.

(Function) As a method of shortening access time, the present invention changes the number of rotations of the disc between the search area and the recording area when recording and reproducing information on an optical disc. Also, when recording and reproducing information in the recording area, the speed is as low as that of a CD.The reason why the rotation speed is increased when recording and reproducing information on the search disk is to shorten the access time. The reason why the rotational speed is lowered when recording and reproducing information in the recording area is to reduce the area of recording bits as much as possible and increase the recording density.

〔Example〕

FIG. 1 is a schematic diagram of an optical disc used in the present invention,
The diameter of the disc is 12 cm, and the data recordable area is 46 m to 116 lm in the radial direction from the center.
Therein, guide grooves are spirally formed at a pitch of 1.6μ. Then, measure from the center to 4
The area from 6- to 501II1 is the search area l,
The area from 50 mm to 116 cm is the recording area 2.

This embodiment is a phase change type optical disc, and the recording film is selenium indium antimony (SeI
nSb) thin film is used. In other words, it takes advantage of the fact that the crystal state changes depending on the presence or absence of laser irradiation, resulting in a difference in reflectance. As a method of driving an optical disc, the linear velocity is kept constant, and when recording and reproducing the search area, the linear velocity is set to 3.6 m/s, and when recording and reproducing the recording area, the linear velocity is set to 3.6 m/s. The speed was set at 1.2 m/sec, which is comparable to a CD. With this, the linear velocity when recording and reproducing the search area is set to 3.6.
m/s, the information transfer speed is 528K B/s, and 176K B/s when recording and reproducing the recording area.
It is three times the second. The rotational speed of the disk is changed when playing back, and the former is faster, and the latter is slower than a CD when recording and playing.By implementing the present invention, it is possible to increase the recording density and reduce the access time. It becomes possible to shorten the length.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram illustrating an optical disc according to the present invention, It is. In the figure, 1 is the search area, and 2 is the record nod area. 〔Effect of the invention〕

Claims (1)

[Scope of Claims] In an optical disc that has an information search area and a recording area in the radial direction of the disc, the rotational speed of the disc when recording and reproducing information in the search area is determined by recording and reproducing information in the recording area. An optical disc device characterized by being able to maintain speed faster than when it is used.