JPH07220281A - Optical disc and optical disc system - Google Patents

Abstract

(57) [Summary] [Object] The present invention has a small recording capacity in a part of a read-only (ROM) disk, but can be easily recorded (R).
(AM) area is provided, information is reproduced by the same optical system as a reproduction-only disc, and a low-cost ROM-RAM mixed disc is obtained. [Structure] Recording is performed by using a heat-sensitive paper and a heating head whose optical characteristics are changed by heat as a medium of a recording unit. For reproduction, the same optical head as in the reproduction-only section is used, and information is reproduced with return light intensity without using autofocus or tracking servo. [Effect] The disk can be manufactured by the same process as the reproduction-only disk, and only the step of sticking the thermal paper is added at the end. Since the reproducing optical system also uses a normal laser and optical system, a recordable disc and a disc system can be constructed at low cost.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an optical disc,
In particular, the present invention relates to a ROM-RAM mixed type optical disc and an optical disc system in which a RAM area capable of recording information is provided in a part of a read-only ROM disc.

[0002]

2. Description of the Related Art A recordable optical disk compatible with a conventional CD (Compact Disk) is disclosed in Japanese Patent Laid-Open No. 2-4.
There is one using an organic film disclosed in Japanese Patent No. 2652. This disc uses a cyanine dye as an organic dye and records information by changing the dye due to substrate deformation and heat change, and the reflectance at the recording point is lowered by the deformation or dye change, and information can be recorded.

Pre-recorded information (ROM)
A disk having a part and a part for adding a recording (RAM) part together can be manufactured by using this material as shown in the above publication. This is the second known example,
JJAP Proc. Int. Symp. on
Optical Memory, 1991, pp. 32
9-331, the ROM information portion forms pits and the RAM portion only the tracking groove is formed by the same process as usual. After this, an organic recording film is applied by spin coating, a reflective film is deposited,
Alternatively, a disk is formed by forming the entire surface with a sputtering ring.

[0004]

The above-mentioned prior art is the second one.
Since the pits are filled with the applied recording film, it is necessary to take measures such as increasing the size of the pits in advance, as described in the prior art. For this reason, there is a problem that the process is different from the normal ROM disk manufacturing process and causes confusion.

Further, for recording, it is necessary to use a laser having a high output 10 times or more that at the time of reproduction, which causes an increase in cost due to the use of the high output laser. Further, in terms of the process, an impurity such as dust is not mixed in, and a highly accurate coating process is required in terms of film thickness, which causes a similar increase in cost.

The conventional technique can be used for a disk and a disk system which require a RAM area having a larger capacity than the cost, but in a system which requires a small recording capacity,
The above cost increase is an important issue.

[0007]

In order to solve the above problems, the present invention adopts a recording method using a heat-sensitive paper or a heat-sensitive material capable of easily recording information. The thermal paper turns black when heat is applied, so that information can be recorded.

Information is reproduced by optically reading this change. Playback is performed with auto focus (A
F) The return light from the pickup is detected without tracking.

In this system, the resolution is small and the recording density is
Lower than the pit. However, if most of the required information is ROM-based information and the information to be recorded is of a memo type, it is possible to record the information more easily than with the method of using a recording medium that causes an increase in cost. The present invention is effective.

Simple recording of information is achieved by the above recording / reproducing method.

[0011]

The thermal paper for recording is attached to a part of the disc. Recording is performed by bringing a heating head into contact with the recording head and applying a recording current corresponding to the information. For reproduction, a read optical head for CD is used, and a voltage is applied to the actuator so that the actuator is moved to an approximate position without using focus servo. If the information recorded at this time is large enough,
The signal intensity due to the returning light can be obtained without autofocusing. Therefore, the information can be read in this state.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a disk system according to the present invention. The disc 1 is composed of a ROM portion 11 in which normal CD-ROM data on the outer peripheral portion is formed by pits, and a RAM portion 12 capable of recording by attaching a thermal paper to the inner periphery of the disc. The optical head 2 uses a semiconductor laser as a light source and an ordinary optical head for CD. The output of this laser is 5mW,
The output on the substrate surface is 0.3 mW at a wavelength of 780 nm.
At the time of data reproduction, an autofocus servo is used to focus on the pit surface on the disc and perform tracking control to read high density data.

On the other hand, at the time of recording, the heating head 3 comes into contact with the thermal paper portion 12 attached to the disc. At this time, according to the information, a recording current is passed through the heat generating head to change the thermal paper by heat, and black and white information is recorded. At this time, recording cannot be performed sufficiently with the normal number of rotations, so the number of rotations is reduced to half and recording is performed.

The optical head 2 is used to read the data recorded on the thermal paper. When reading data from this portion, the optical head moves to the position of the RAM portion 12 of the thermal paper. After that, the data is read by the return light of the semiconductor laser. At this time, neither focus nor tracking is used for servo. A constant voltage is applied to the focus actuator, and the focus position is adjusted so that it is approximately on the thermal paper. In the present embodiment, the focus actuator was adjusted in position by applying a constant voltage to the focus actuator.However, when a system that was previously adjusted to the optimum position by adjusting the spring strength of the actuator was used, adjustment by voltage application was not performed. No need.

Since the data recorded on the thermal paper has a pit area much larger than that of the ROM portion, the data can be read out without the focus and tracking servo.

In this embodiment, the pit size of the ROM portion is the same as that of a normal CD, the track pitch is 1.6 μm,
The shortest pit length is 0.9 μm. On the other hand, the data recorded on the thermal paper has a track pitch of 1.5 mm and a minimum pit length of 0.1 mm, and the recording density is about 1 / 100,000.
Is.

FIG. 2 shows the ROM and RAM areas on the disk. FIG. 3 schematically shows a state of recording.
The RAM area has a radius of 25 mm to 40 mm and a capacity of about 2 kB. ROM part is 40mm to 6
Up to 0 mm, its capacity is about 400 MB.

In the case of this embodiment, a system is used in which map information is recorded in the ROM area and information indicating a desired point is recorded in the RAM area. In the system of this example, it is used when making a memo of the destination when used for navigation, and about 2B is used for one point information. Therefore, it is possible to record about 1000 points.

When recording the point name, etc., 2
About 0B is required, and in this case, about 100 points and point names can be recorded.

Other simple information recording applications include the memory of the progress of games, the maximum score, etc., the recording of the number of correct answers to problems in educational software, and the personal "bookmark" function in the database. is there. 2B in either case
Since a capacity of about 20B is enough, about 100 to 10
It can be used 00 times.

Furthermore, even if the capacity is exhausted,
It can be done by replacing the thermal paper.

FIG. 4 shows some embodiments of a method for pasting thermal paper.

(A) is a case where it is directly attached to the beam incident surface. In this case, it can be manufactured by the same process as the conventional disk.

(B) is one in which a concave portion is formed on the substrate, and thermal paper is stuck to this portion. In this case, the beam thermal paper surface is lower than the substrate surface and approaches the surface of the ROM section.
This makes it easy to adjust the position of the actuator during reproduction of the RAM section.

In (c), a heat-sensitive material is applied instead of heat-sensitive paper. In this embodiment, as in the case of (a), the beam incident surface is coated. This can be applied to the same position as in (b).

(D) is an example of the case where a heat-sensitive material is formed on the back surface of the substrate by coating. In this case, the thermal paper is RO
Since it is exactly the same as the surface of the M part, the position adjustment is easier. Similarly, the heat-sensitive material can be formed by a printing technique.

The above examples are the thermal papers usually used,
Alternatively, a heat-sensitive material is used, but other than this, for example, a rewritable material using an organic low molecular weight compound and a heat-sensitive recording layer may be used.

FIG. 5 shows another embodiment. In this embodiment, bar code information is recorded on a label attached in advance. This bar code information is a standardized normal bar code, and does not require any special technique for production. The information in this bar code is read by the method according to the invention. According to the present invention, information can be read even if the laser wavelength, tracking characteristics, recording format, etc. are different. Therefore, the disc can be easily discriminated by reading a barcode sticker on which disc information is recorded in advance from the disc.

In this embodiment, information at the time of reproduction is recorded on the disc. The reproduction information is information that the player reproduces based on this, and information such as repeatedly reproducing a chapter recorded on the disc, arbitrarily setting the reproduction order of chapters, or automatically repeating one side is recorded. Is. This information was manually input when performing a demonstration, but according to the present embodiment, since the reproduction of the desired program is automatically started after the disc is inserted, a person who does not have knowledge of the disc Even if it is set, a predetermined demonstration can be done.

[0030]

According to the present invention, normal reproduction only (RO
M) It is possible to provide a disc having an information recordable (RAM) area while using the disc manufacturing process.

Further, since the same optical head as the ROM disk is used as the optical head, cost reduction can be achieved as a recording / reproducing system.

[Brief description of drawings]

FIG. 1 is a diagram showing an optical disc system according to the present invention.

FIG. 2 is a diagram showing a configuration of an optical disc according to the present invention.

FIG. 3 is a diagram showing a state in which information is recorded on an optical disc according to the present invention.

FIG. 4 is a diagram showing a disc structure according to the present invention.

FIG. 5 is a diagram showing another configuration of the optical disc according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Disk, 2 ... Optical head, 3 ... Heating head, 11 ... ROM part, 12 ... RAM part 21 ... Optical head control part 31 ... Heating head control part.

Claims (5)

[Claims] 1. An optical disc in which pits corresponding to information are formed on a substrate, and an autofocus function for condensing laser light on the disc using the optical head.
A system that has a tracking servo function to trace over data pits and reads the data on the disc by the intensity of the returned light of the focused laser beam, and forms optical binary information on the disc separately from the data pits. An optical disc system comprising a data reading optical head and a reading system without using a tracking servo or an autofocus servo. 2. The system according to claim 1, wherein
As optical binary information, optical binary information consisting of a substantially black-and-white pattern directly formed on a disc by using a technique such as coating or printing, or an optical binary information consisting of a substantially black-and-white pattern printed on paper. An optical disc characterized by being formed. 3. The optical disk system according to claim 1, wherein a material whose optical characteristics are changed by heat is formed on a disk in a region other than the data pits on the disk, and the heat for recording is formed. Using a heating head that generates
An optical disk system characterized in that a heating head is brought into contact with or in proximity to record optical binary information in black and white, and this signal is read by the optical head. 4. The disk according to claim 3, wherein
An optical disk system characterized in that a thermal paper is pasted on a disk as a material whose optical characteristics are changed, a heating head is used to record a black and white signal, and the signal is read by the optical head. 5. Information of a disc is recorded on a black and white signal,
An optical disc system characterized by performing disc discrimination and reproduction control by reading this information at the start of reading.