Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
2001-08-31
2003-03-11
Pham, Hai (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
Reexamination Certificate
active
06532034
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of writing figures, such as letters and pictures that are visible to the naked eye, on an optical disk, and also to an optical disk apparatus having a function to visibly write figures, such as letters and pictures, on an optical disk.
There are several principles by which information is recorded on a thin film (recording film) by irradiation with a laser beam. Among them, the one which utilizes the change of atomic arrangement by irradiation with a laser beam, such as the phase change (also called phase transition) and photo-darkening of the film material, which is accompanied by very little deformation of the thin film, has the advantage that an optical disk of double-side disk structure, or a multi-layer optical disk having a plurality of information planes, can be obtained by directly bonding together two sheets of disk members. Such conventional optical disks as CD-R, CD-RW, PD, DVD-R, DVD-RW, and DVD-RAM disks reproduce recorded information by using an apparatus with a built-in laser.
The conventional optical disk needs a reproducing apparatus with a built-in laser source for reproduction of information recorded on an optical disk. Also, the content which the user has recorded on an optical disk could not be confirmed unless the optical disk is reproduced by the reproducing apparatus.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an optical disk on which visible letters and marks can be made without requiring a reproducing apparatus. A further object of the present invention is to provide a method of recording visible letters, pictures and marks on an optical disk without requiring a reproducing apparatus.
An optical disk is a discoid-shaped recording medium in which information, which can be reproduced by using a difference in reflectivity, has been recorded or can be recorded. An optical disk comes in various types, such as one which has one layer of recording film, one which has two or more layers of recording film, one which has a ROM region and a RAM region, one which is capable of recording and reproducing many times, and one which is capable of recording once and which permits reproduction many times.
For the recording film of an optical disk, phase-changing materials, such as Ge—Sb—Te, In—Sb—Te, Ag—In—Sb—Te, germanide, antimonide, telluride, indide, etc., are usually used. An optical disk that uses a phase-changing material for the recording film records information by utilizing the fact that the phase-changing material of the recording film becomes crystalline or amorphous in response to irradiation with a laser beam which has been modulated by recording information and performs reproduction of information by utilizing the difference in reflectivity between the crystalline region and amorphous region.
It is also possible to use for the recording film an organic pigment capable of discoloration by light irradiation/heating in addition to the phase-changing material. The optical disk that uses an organic pigment for the recording film performs recording and reproducing by utilizing the fact that the hue changes because the discolored region and the colored region differ in reflectivity at visible wavelengths. The optical disk that uses an organic pigment is the same as the optical disk that uses a phase-changing material as far as the writing method and reproducing method are concerned, except that rewriting is impossible if the amorphous state is replaced by discoloration and the crystalline state is replaced by coloration in the phase-changing material. The present invention can be applied to optical disks of any type, so long as they are optical disks having a recording film or recording region capable of recording by a laser beam.
FIG. 1
is a diagram showing the difference in reflectivity in the case where a typical optical disk recording film material is made crystalline and amorphous, with the abscissa representing wavelength and the ordinate representing reflectivity. Ramo denotes reflectivity when the recording film material is made amorphous and Rcry denotes reflectivity when it is made crystalline. Recording of information in an ordinary optical disk is accomplished by forming amorphous recording marks by laser beam irradiation along the track of the crystalline recording film. And, reproduction of recording information is accomplished by reading off the position of recorded marks or the position of mark edges by utilizing the detected difference in reflectivity between the crystalline region and the amorphous region. The track width of the optical disk is about 0.1-0.8 &mgr;m, and the mark length is about 0.1-8 &mgr;m; and, since recording marks are extremely small, it is impossible to recognize individual recording marks with the naked eye.
The present inventors have turned their attention to the fact that the reflectivity of the crystalline region and amorphous region of the optical disk recording film material greatly varies in the visible region, and they have conceived that, if large letters and pictures crossing a plurality of tracks are depicted as figures in the recording film by connecting amorphous regions, it will be possible to recognize them with the naked eye by a difference in reflectivity between the amorphous region constituting the letters and pictures and the surrounding crystalline region. Thus, the present inventors have developed a method of writing such figures and a figure writing apparatus to carry out the method. Incidentally, the figure writing apparatus can be realized by incorporating a program for figure writing in an ordinary optical disk recording apparatus.
In this specification, “recording” means forming recording marks having “1” and “0” information by changing the atomic arrangement in the recording film of the optical disk by irradiation with light. “Writing” means writing visible letters and pictures in the optical disk by changing the atomic arrangement in the recording film of the optical disk by light irradiation or heating. “Erasing” means erasing information recorded in the optical disk or making invisible letters and pictures written in the optical disk.
By the present invention, the following optical disk, optical disk apparatus, or method for writing figures in the optical disk are provided.
(1) An optical disk having a first region and a second region divided in the radial direction is characterized in that data is recorded in said first region by recording marks, and a visible figure is written in said second region by gathering element regions in which the average reflectivity per area of 0.01 mm×0.01 mm differs more than 5% from the background region at any of the visible wavelengths.
The visible figure includes pictures, letters, symbols, etc. The background region denotes a region other than element regions of the second region, that is, the region which becomes the background of the visible figure formed by gathering element regions.
(2) An optical disk having a plurality of recording films is characterized in that data is recorded in said first recording film by recording marks, and a visible figure is written in said second recording film, which is different from said first recording film, by gathering element regions in which the average reflectivity per area of 0.01 mm×0.01 mm differs more than 5% from the background region at any of the visible wavelengths.
The visible figure includes pictures, letters, symbols, etc. The background region denotes a region other than element regions of the second region, that is, the region which becomes the background of the visible figure formed by gathering element regions.
(3) An optical disk has a region in which data for figure writing by recording marks has been recorded and a region in which a visible figure has been formed by gathering element regions in which the average reflectivity per area of 0.01 mm×0.01 mm differs more than 5% from the background region at any of the visible wavelengths, which is written based on said data for figure
Anzai Yumiko
Hirotsune Akemi
Nishi Yoshiko
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Pham Hai
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