Method of recording information on an optical information recording medium

Abstract

An optical information recording medium includes a substrate having disposed thereon a recording layer that is recordable by irradiating the recording layer with a laser having a wavelength of 450 nm or less. The recording layer contains a specific phthalocyanine derivative. An optical information recording method uses the medium.

Description

[0001] This is a divisional of application Ser. No. 10 / 180,099 filed Jun. 27, 2002. The entire disclosure of the prior application, application Ser. No. 10 / 180,099 incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an optical information recording method, in which information is recorded and played back with a laser, and to an optical information recording medium used in the method. In particular, the invention relates to a heat-mode optical information recording medium on which information is recorded by irradiating the medium with a shortwave laser having a wavelength of 450 nm or shorter, and to an optical information recording method using the medium. [0004] 2. Description of the Related Art [0005] A CD-R is a writable, optical information recording medium (optical disc) on which information can be written only once by irradiation with a laser, and has conventionally been known. A CD-R typically c...

AI Technical Summary

Benefits of technology

[0011] It is an object of the present invention to provide an optical information recording method and a medium used therein, with which information can be recorded and played back by irradiating the medium with a shortwave laser having a wavelength of 450 nm, and in particular a highly versatile semiconductor laser having a wavelength in the vicinity of 405 nm, and that exhibit excellent recording characteristics.

[0012] It is a second object of the invention to provide an optical information recording method and medium used therein, in which information recorded on the medium can be stored over a long period of time by designing a recording layer that is stable with respect to high temperature and high humidity.

[0013] It is a third object of the invention to provide a highly versatile optical information recording method and medium used therein, with which information can be recorded and played back by irradiating the medium with both a shortwave laser having a wavelength of 450 nm or less and a laser having a wavelength of 750 to 850 nm that is used in a conventional CD-R.

[0018] A third aspect of the invention is an optical information recording medium used in a method of recording information by irradiating the medium with a laser having a wavelength no greater than 450 nm, wherein a recording layer of the optical information recording medium contains a phthalocyanine derivative having a substituent at an α-position thereof. The phthalocyanine derivative has a main absorption band of around 700 nm and a sub-absorption band of around 340 nm. By using the phthalocyanine derivative as the recording material for the recording layer, an optical information recording medium that has high sensitivity to a laser having a short wavelength of 450 nm or less, good recording and playback characteristics, high reflectance, and high percentage modulation is obtained. The optical information recording medium also has high sensitivity to a laser having a wavelength of 750 to 850 nm, good recording and playback characteristics, high reflectance, and high percentage modulation.

Problems solved by technology

While DVD-Rs have to a certain extent secured a position as large-capacity recording media, they still do not possess a sufficiently large recording capacity to meet the demands of the future.

However, the present inventors have ascertained that further improvement is needed because, when information is recorded on the above-described conventional optical discs by irradiating the discs with a shortwave laser having a wavelength of 450 nm or less, recording characteristics, such as reflectance and percentage modulation, are not satisfactory and storage stability is insufficient.

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