Optical recording medium, optical recording method, optical reproducing method, optical recording device, optical reproducing device, and optical recording/reproducing device

An optical recording method for performing additional recording by thermal recording such that the reflectance is changed due to the change of property of reflective film by irradiating laser beam modulated by additional recording information signal on optical medium, said optical medium having an information layer with a reflective film on which an information recording portion is formed by physical change of shape at least in one direction of thickness and track width, said reflective film having such a structure that additional recording can be performed by thermal recording, and that the reflectance of said reflective film changes in the range of 0.5%<(|R0−R1|/R0)×100%<17%, where R0 is reflectance of non-recording state and R1 is reflectance of recording state for reproducing beam.

An optical reproducing method for performing reproduction of additional recording such that fine change of return beam is performed due to the change of reflectance by irradiating laser beam on optical medium, said optical medium having an information layer with a reflective film on which an information recording portion is formed by physical change of shape at least in one direction of thickness and track width,

• wherein,
• said reflective film having such a structure that additional recording can be performed by thermal recording, and that the reflectance of said reflective film changes in the range of 0.5%<(|R0−R1|/R0)×100%<17%, where R0 is reflectance of non-recording state and R1 is reflectance of recording state for reproducing beam.

An optical recording apparatus comprising optical recording means for optical medium, said optical medium having an information layer with a reflective film on which an information recording portion is formed by physical change of shape at least in one direction of thickness and track width, said reflective film having such a structure that additional recording can be performed by thermal recording, and that the reflectance of said reflective film changes in the range of 0.5%<(|R0−R1|/R0)×100%<17%, where R0 is reflectance of non-recording state and R1 is reflectance of recording state for reproducing beam,

• wherein,
• said optical recording means has irradiation means for irradiating on optical medium laser beam which can be modulated in response to additional recording information to perform additional recording by thermal recording such that the reflectance is changed due to the change of property of reflective film by the irradiation of laser beam.

An optical reproducing apparatus comprising optical reproducing means for optical medium, said optical medium having an information layer with a reflective film on which an information recording portion is formed by physical change of shape at least in one direction of thickness and track width, said reflective film having such a structure that additional recording can be performed by thermal recording, and that the reflectance of said reflective film changes in the range of 0.5%<(|R0−R1|/R0)×100%<17%, where R0 is reflectance of non-recording state and R1 is reflectance of recording state for reproducing beam,

• wherein,
• said optical reproducing means has irradiation means for irradiating reproducing beam on optical medium and detecting means for detecting return beam from said reflective film, fine change of detecting output from said detecting means being reproduction signal of said additional recording.

An optical recording and reproducing apparatus comprising optical recording means and optical reproducing means for optical medium, said optical medium having an information layer with a reflective film on which an information recording portion is formed by physical change of shape at least in one direction of thickness and track width, said reflective film having such a structure that additional recording can be performed by thermal recording, and that the reflectance of said reflective film changes in the range of 0.5%<(|R0−R1|/R0)×100%<17%, where R0 is reflectance of non-recording state and R1 is reflectance of recording state for reproducing beam

• wherein,
• said optical recording means has irradiation means for irradiating reproducing beam on optical medium and detecting means for detecting return beam from said reflective film, fine change of detecting output from said detecting means being reproduction signal of said additional recording, said optical reproducing means has irradiation means for irradiating reproducing mean on optical medium and detecting means for detecting return beam from said reflective film, fine change of detecting output from said detecting means being reproduction signal of said additional recording.